[PATCH v2 0/68] war on sprintf

[PATCH v2 0/68] war on sprintf

[Jeff King]

This is a revised version of the series I sent earlier[1].

For those just joining us, the goal is to remove sprintf, strcpy, etc,
to make it easier to audit the code base for buffer overflows. I've been
addressing review comments for individual patches as the discussion
progressed, so there's nothing here that hasn't been on the list (and I
think I've addressed all of the comments from the first round of
review).

Here's a list of the commits, with an overview[2] of the changes from v1
(patches without comment are the same as in v1):

  [01/68]: show-branch: avoid segfault with --reflog of unborn branch
  [02/68]: mailsplit: fix FILE* leak in split_maildir
  [03/68]: archive-tar: fix minor indentation violation
  [04/68]: fsck: don't fsck alternates for connectivity-only check
  [05/68]: add xsnprintf helper function
  [06/68]: add git_path_buf helper function
  [07/68]: strbuf: make strbuf_complete_line more generic

    Docstring now makes clear the behavior when the strbuf is empty.

  [08/68]: add reentrant variants of sha1_to_hex and find_unique_abbrev

    These are now called sha1_to_hex_r, etc. The re-entrancy conditions
    are documented.

  [09/68]: fsck: use strbuf to generate alternate directories
  [10/68]: mailsplit: make PATH_MAX buffers dynamic

    Use xstrfmt consistently instead of sometimes using a strbuf.

  [11/68]: trace: use strbuf for quote_crnl output

    Further cleanup of "p2" variable in quote_crnl.

  [12/68]: progress: store throughput display in a strbuf
  [13/68]: test-dump-cache-tree: avoid overflow of cache-tree name
  [14/68]: compat/inet_ntop: fix off-by-one in inet_ntop4
  [15/68]: convert trivial sprintf / strcpy calls to xsnprintf

    Prefer "fixed-size" to "static" for clarity in commit message.

  [16/68]: archive-tar: use xsnprintf for trivial formatting
  [17/68]: use xsnprintf for generating git object headers
  [18/68]: find_short_object_filename: convert sprintf to xsnprintf
  [19/68]: stop_progress_msg: convert sprintf to xsnprintf

    Ditto on "fixed-size" versus "static".

  [20/68]: compat/hstrerror: convert sprintf to snprintf
  [21/68]: grep: use xsnprintf to format failure message
  [22/68]: entry.c: convert strcpy to xsnprintf
  [23/68]: add_packed_git: convert strcpy into xsnprintf

    Drop useless comment. Add comment on magic strlen().

  [24/68]: http-push: replace strcat with xsnprintf
  [25/68]: receive-pack: convert strncpy to xsnprintf
  [26/68]: replace trivial malloc + sprintf / strcpy calls with xstrfmt

    Include NUL in base64 of imap-send cram response. My guess is this
    is a bug in what we send that is overlooked by most servers, but I'd
    prefer to be conservative here and keep the behavior the same.

  [27/68]: config: use xstrfmt in normalize_value
  [28/68]: fetch: replace static buffer with xstrfmt
  [29/68]: use strip_suffix and xstrfmt to replace suffix
  [30/68]: ref-filter: drop sprintf and strcpy calls
  [31/68]: help: drop prepend function in favor of xstrfmt
  [32/68]: mailmap: replace strcpy with xstrdup
  [33/68]: read_branches_file: simplify string handling

    This goes much further than the original in cleaning up the use of a
    static buffer. From what I sent earlier during review, I dropped
    strbuf_read_file in favor of strbuf_getline, to keep the behavior
    identical to the original.

  [34/68]: read_remotes_file: simplify string handling

    New in this iteration; cleanups to match those in 33/68.

  [35/68]: resolve_ref: use strbufs for internal buffers
  [36/68]: upload-archive: convert sprintf to strbuf
  [37/68]: remote-ext: simplify git pkt-line generation

    The v1 of this patch was totally buggy. This is a rewrite to use
    packet_write(), which has several advantages, and includes tests.

  [38/68]: http-push: use strbuf instead of fwrite_buffer
  [39/68]: http-walker: store url in a strbuf
  [40/68]: sha1_get_pack_name: use a strbuf
  [41/68]: init: use strbufs to store paths
  [42/68]: apply: convert root string to strbuf
  [43/68]: transport: use strbufs for status table "quickref" strings
  [44/68]: merge-recursive: convert malloc / strcpy to strbuf
  [45/68]: enter_repo: convert fixed-size buffers to strbufs
  [46/68]: remove_leading_path: use a strbuf for internal storage
  [47/68]: write_loose_object: convert to strbuf

    Clarify comment on subtle mkstemp behavior.

  [48/68]: diagnose_invalid_index_path: use strbuf to avoid strcpy/strcat
  [49/68]: fetch-pack: use argv_array for index-pack / unpack-objects
  [50/68]: http-push: use an argv_array for setup_revisions
  [51/68]: stat_tracking_info: convert to argv_array
  [52/68]: daemon: use cld->env_array when re-spawning
  [53/68]: use sha1_to_hex_r() instead of strcpy

    Use "_r" versions to match change in patch 8.

  [54/68]: drop strcpy in favor of raw sha1_to_hex

    More history in the commit message, courtesy of Eric.

  [55/68]: color: add overflow checks for parsing colors

    Be more careful with OUT() macro.

  [56/68]: use alloc_ref rather than hand-allocating "struct ref"
  [57/68]: avoid sprintf and strcpy with flex arrays

    Trivial typo-fix in comment.

  [58/68]: receive-pack: simplify keep_arg computation

    Another s/static/fixed-size/.

  [59/68]: help: clean up kfmclient munging
  [60/68]: prefer memcpy to strcpy
  [61/68]: color: add color_set helper for copying raw colors
  [62/68]: notes: document length of fanout path with a constant
  [63/68]: convert strncpy to memcpy
  [64/68]: fsck: drop inode-sorting code
  [65/68]: Makefile: drop D_INO_IN_DIRENT build knob
  [66/68]: fsck: use for_each_loose_file_in_objdir
  [67/68]: use strbuf_complete to conditionally append slash

    Drop bogus conversion from imap-send.

  [68/68]: name-rev: use strip_suffix to avoid magic numbers

Hopefully that makes reviewing v2 a little less painful for those who
already slogged through v1. Thanks for your patience. :)

-Peff

[1] Gmane seems down, but once it's back up you should be able to get to
    v1 at: http://mid.gmane.org/20150915152125.GA27504@sigill.intra.peff.net

[2] Keeping track of the tweaks to this many patches would have been
    near impossible without Thomas Rast's git-tbdiff tool:

      https://github.com/trast/tbdiff

    I highly recommend it for people handling multiple versions of a
    long series.

[PATCH 01/68] show-branch: avoid segfault with --reflog of unborn branch

[Jeff King]

When no branch is given to the "--reflog" option, we resolve
HEAD to get the default branch. However, if HEAD points to
an unborn branch, resolve_ref returns NULL, and we later
segfault trying to access it.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/show-branch.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 408ce70..092b59b 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -743,6 +743,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 			fake_av[1] = NULL;
 			av = fake_av;
 			ac = 1;
+			if (!*av)
+				die("no branches given, and HEAD is not valid");
 		}
 		if (ac != 1)
 			die("--reflog option needs one branch name");
-- 
2.6.0.rc3.454.g204ad51

[PATCH 02/68] mailsplit: fix FILE* leak in split_maildir

[Jeff King]

If we encounter an error while splitting a maildir, we exit
the function early, leaking the open filehandle. This isn't
a big deal, since we exit the program soon after, but it's
easy enough to be careful.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/mailsplit.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/builtin/mailsplit.c b/builtin/mailsplit.c
index 8e02ea1..9de06e3 100644
--- a/builtin/mailsplit.c
+++ b/builtin/mailsplit.c
@@ -150,6 +150,7 @@ static int split_maildir(const char *maildir, const char *dir,
 {
 	char file[PATH_MAX];
 	char name[PATH_MAX];
+	FILE *f = NULL;
 	int ret = -1;
 	int i;
 	struct string_list list = STRING_LIST_INIT_DUP;
@@ -160,7 +161,6 @@ static int split_maildir(const char *maildir, const char *dir,
 		goto out;
 
 	for (i = 0; i < list.nr; i++) {
-		FILE *f;
 		snprintf(file, sizeof(file), "%s/%s", maildir, list.items[i].string);
 		f = fopen(file, "r");
 		if (!f) {
@@ -177,10 +177,13 @@ static int split_maildir(const char *maildir, const char *dir,
 		split_one(f, name, 1);
 
 		fclose(f);
+		f = NULL;
 	}
 
 	ret = skip;
 out:
+	if (f)
+		fclose(f);
 	string_list_clear(&list, 1);
 	return ret;
 }
-- 
2.6.0.rc3.454.g204ad51

[PATCH 03/68] archive-tar: fix minor indentation violation

[Jeff King]

This looks like a simple omission from 8539070 (archive-tar:
unindent write_tar_entry by one level, 2012-05-03).

Signed-off-by: Jeff King <peff@peff.net>
---
 archive-tar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/archive-tar.c b/archive-tar.c
index 0d1e6bd..b6b30bb 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -233,7 +233,7 @@ static int write_tar_entry(struct archiver_args *args,
 		size_t rest = pathlen - plen - 1;
 		if (plen > 0 && rest <= sizeof(header.name)) {
 			memcpy(header.prefix, path, plen);
-				memcpy(header.name, path + plen + 1, rest);
+			memcpy(header.name, path + plen + 1, rest);
 		} else {
 			sprintf(header.name, "%s.data",
 				sha1_to_hex(sha1));
-- 
2.6.0.rc3.454.g204ad51

[PATCH 04/68] fsck: don't fsck alternates for connectivity-only check

[Jeff King]

Commit 02976bf (fsck: introduce `git fsck --connectivity-only`,
2015-06-22) recently gave fsck an option to perform only a
subset of the checks, by skipping the fsck_object_dir()
call. However, it does so only for the local object
directory, and we still do expensive checks on any alternate
repos. We should skip them in this case, too.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fsck.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 0794703..46c7235 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -678,16 +678,17 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 	git_config(fsck_config, NULL);
 
 	fsck_head_link();
-	if (!connectivity_only)
+	if (!connectivity_only) {
 		fsck_object_dir(get_object_directory());
 
-	prepare_alt_odb();
-	for (alt = alt_odb_list; alt; alt = alt->next) {
-		char namebuf[PATH_MAX];
-		int namelen = alt->name - alt->base;
-		memcpy(namebuf, alt->base, namelen);
-		namebuf[namelen - 1] = 0;
-		fsck_object_dir(namebuf);
+		prepare_alt_odb();
+		for (alt = alt_odb_list; alt; alt = alt->next) {
+			char namebuf[PATH_MAX];
+			int namelen = alt->name - alt->base;
+			memcpy(namebuf, alt->base, namelen);
+			namebuf[namelen - 1] = 0;
+			fsck_object_dir(namebuf);
+		}
 	}
 
 	if (check_full) {
-- 
2.6.0.rc3.454.g204ad51

[PATCH 05/68] add xsnprintf helper function

[Jeff King]

There are a number of places in the code where we call
sprintf(), with the assumption that the output will fit into
the buffer. In many cases this is true (e.g., formatting a
number into a large buffer), but it is hard to tell
immediately from looking at the code. It would be nice if we
had some run-time check to make sure that our assumption is
correct (and to communicate to readers of the code that we
are not blindly calling sprintf, but have actually thought
about this case).

This patch introduces xsnprintf, which behaves just like
snprintf, except that it dies whenever the output is
truncated. This acts as a sort of assert() for these cases,
which can help find places where the assumption is violated
(as opposed to truncating and proceeding, which may just
silently give a wrong answer).

Signed-off-by: Jeff King <peff@peff.net>
---
 git-compat-util.h |  3 +++
 wrapper.c         | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/git-compat-util.h b/git-compat-util.h
index f649e81..348b9dc 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -744,6 +744,9 @@ static inline size_t xsize_t(off_t len)
 	return (size_t)len;
 }
 
+__attribute__((format (printf, 3, 4)))
+extern int xsnprintf(char *dst, size_t max, const char *fmt, ...);
+
 /* in ctype.c, for kwset users */
 extern const unsigned char tolower_trans_tbl[256];
 
diff --git a/wrapper.c b/wrapper.c
index 0e22d43..6fcaa4d 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -621,6 +621,22 @@ char *xgetcwd(void)
 	return strbuf_detach(&sb, NULL);
 }
 
+int xsnprintf(char *dst, size_t max, const char *fmt, ...)
+{
+	va_list ap;
+	int len;
+
+	va_start(ap, fmt);
+	len = vsnprintf(dst, max, fmt, ap);
+	va_end(ap);
+
+	if (len < 0)
+		die("BUG: your snprintf is broken");
+	if (len >= max)
+		die("BUG: attempt to snprintf into too-small buffer");
+	return len;
+}
+
 static int write_file_v(const char *path, int fatal,
 			const char *fmt, va_list params)
 {
-- 
2.6.0.rc3.454.g204ad51

[PATCH 06/68] add git_path_buf helper function

[Jeff King]

If you have a function that uses git_path a lot, but would
prefer to avoid the static buffers, it's useful to keep a
single scratch buffer locally and reuse it for each call.
You used to be able to do this with git_snpath:

  char buf[PATH_MAX];

  foo(git_snpath(buf, sizeof(buf), "foo"));
  bar(git_snpath(buf, sizeof(buf), "bar"));

but since 1a83c24, git_snpath has been replaced with
strbuf_git_path. This is good, because it removes the
arbitrary PATH_MAX limit. But using strbuf_git_path is more
awkward for two reasons:

  1. It adds to the buffer, rather than replacing it. This
     is consistent with other strbuf functions, but makes
     reuse of a single buffer more tedious.

  2. It doesn't return the buffer, so you can't format
     as part of a function's arguments.

The new git_path_buf solves both of these, so you can use it
like:

  struct strbuf buf = STRBUF_INIT;

  foo(git_path_buf(&buf, "foo"));
  bar(git_path_buf(&buf, "bar"));

  strbuf_release(&buf);

Signed-off-by: Jeff King <peff@peff.net>
---
 cache.h |  2 ++
 path.c  | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/cache.h b/cache.h
index 79066e5..e231e47 100644
--- a/cache.h
+++ b/cache.h
@@ -723,6 +723,8 @@ extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
 extern void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 	__attribute__((format (printf, 2, 3)));
+extern char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
+	__attribute__((format (printf, 2, 3)));
 extern void strbuf_git_path_submodule(struct strbuf *sb, const char *path,
 				      const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
diff --git a/path.c b/path.c
index 95acbaf..46a4d27 100644
--- a/path.c
+++ b/path.c
@@ -175,6 +175,16 @@ static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
 	strbuf_cleanup_path(buf);
 }
 
+char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
+{
+	va_list args;
+	strbuf_reset(buf);
+	va_start(args, fmt);
+	do_git_path(buf, fmt, args);
+	va_end(args);
+	return buf->buf;
+}
+
 void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 {
 	va_list args;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 07/68] strbuf: make strbuf_complete_line more generic

[Jeff King]

The strbuf_complete_line function makes sure that a buffer
ends in a newline. But we may want to do this for any
character (e.g., "/" on the end of a path). Let's factor out
a generic version, and keep strbuf_complete_line as a thin
wrapper.

Signed-off-by: Jeff King <peff@peff.net>
---
 strbuf.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/strbuf.h b/strbuf.h
index aef2794..43f27c3 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -491,10 +491,21 @@ extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *
  */
 extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
 
+/**
+ * "Complete" the contents of `sb` by ensuring that either it ends with the
+ * character `term`, or it is empty.  This can be used, for example,
+ * to ensure that text ends with a newline, but without creating an empty
+ * blank line if there is no content in the first place.
+ */
+static inline void strbuf_complete(struct strbuf *sb, char term)
+{
+	if (sb->len && sb->buf[sb->len - 1] != term)
+		strbuf_addch(sb, term);
+}
+
 static inline void strbuf_complete_line(struct strbuf *sb)
 {
-	if (sb->len && sb->buf[sb->len - 1] != '\n')
-		strbuf_addch(sb, '\n');
+	strbuf_complete(sb, '\n');
 }
 
 extern int strbuf_branchname(struct strbuf *sb, const char *name);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 08/68] add reentrant variants of sha1_to_hex and find_unique_abbrev

[Jeff King]

The sha1_to_hex and find_unique_abbrev functions always
write into reusable static buffers. There are a few problems
with this:

  - future calls overwrite our result. This is especially
    annoying with find_unique_abbrev, which does not have a
    ring of buffers, so you cannot even printf() a result
    that has two abbreviated sha1s.

  - if you want to put the result into another buffer, we
    often strcpy, which looks suspicious when auditing for
    overflows.

This patch introduces sha1_to_hex_r and find_unique_abbrev_r,
which write into a user-provided buffer. Of course this is
just punting on the overflow-auditing, as the buffer
obviously needs to be GIT_SHA1_HEXSZ + 1 bytes. But it is
much easier to audit, since that is a well-known size.

We retain the non-reentrant forms, which just become thin
wrappers around the reentrant ones. This patch also adds a
strbuf variant of find_unique_abbrev, which will be handy in
later patches.

Signed-off-by: Jeff King <peff@peff.net>
---
 cache.h     | 31 ++++++++++++++++++++++++++++++-
 hex.c       | 13 +++++++++----
 sha1_name.c | 16 +++++++++++-----
 strbuf.c    |  9 +++++++++
 strbuf.h    |  8 ++++++++
 5 files changed, 67 insertions(+), 10 deletions(-)

diff --git a/cache.h b/cache.h
index e231e47..030b880 100644
--- a/cache.h
+++ b/cache.h
@@ -785,7 +785,24 @@ extern char *sha1_pack_name(const unsigned char *sha1);
  */
 extern char *sha1_pack_index_name(const unsigned char *sha1);
 
-extern const char *find_unique_abbrev(const unsigned char *sha1, int);
+/*
+ * Return an abbreviated sha1 unique within this repository's object database.
+ * The result will be at least `len` characters long, and will be NUL
+ * terminated.
+ *
+ * The non-`_r` version returns a static buffer which will be overwritten by
+ * subsequent calls.
+ *
+ * The `_r` variant writes to a buffer supplied by the caller, which must be at
+ * least `GIT_SHA1_HEXSZ + 1` bytes. The return value is the number of bytes
+ * written (excluding the NUL terminator).
+ *
+ * Note that while this version avoids the static buffer, it is not fully
+ * reentrant, as it calls into other non-reentrant git code.
+ */
+extern const char *find_unique_abbrev(const unsigned char *sha1, int len);
+extern int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len);
+
 extern const unsigned char null_sha1[GIT_SHA1_RAWSZ];
 
 static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
@@ -1067,6 +1084,18 @@ extern int for_each_abbrev(const char *prefix, each_abbrev_fn, void *);
 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 extern int get_oid_hex(const char *hex, struct object_id *sha1);
 
+/*
+ * Convert a binary sha1 to its hex equivalent. The `_r` variant is reentrant,
+ * and writes the NUL-terminated output to the buffer `out`, which must be at
+ * least `GIT_SHA1_HEXSZ + 1` bytes, and returns a pointer to out for
+ * convenience.
+ *
+ * The non-`_r` variant returns a static buffer, but uses a ring of 4
+ * buffers, making it safe to make multiple calls for a single statement, like:
+ *
+ *   printf("%s -> %s", sha1_to_hex(one), sha1_to_hex(two));
+ */
+extern char *sha1_to_hex_r(char *out, const unsigned char *sha1);
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern char *oid_to_hex(const struct object_id *oid);	/* same static buffer as sha1_to_hex */
 
diff --git a/hex.c b/hex.c
index 899b74a..0519f85 100644
--- a/hex.c
+++ b/hex.c
@@ -61,12 +61,10 @@ int get_oid_hex(const char *hex, struct object_id *oid)
 	return get_sha1_hex(hex, oid->hash);
 }
 
-char *sha1_to_hex(const unsigned char *sha1)
+char *sha1_to_hex_r(char *buffer, const unsigned char *sha1)
 {
-	static int bufno;
-	static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
 	static const char hex[] = "0123456789abcdef";
-	char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
+	char *buf = buffer;
 	int i;
 
 	for (i = 0; i < GIT_SHA1_RAWSZ; i++) {
@@ -79,6 +77,13 @@ char *sha1_to_hex(const unsigned char *sha1)
 	return buffer;
 }
 
+char *sha1_to_hex(const unsigned char *sha1)
+{
+	static int bufno;
+	static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
+	return sha1_to_hex_r(hexbuffer[3 & ++bufno], sha1);
+}
+
 char *oid_to_hex(const struct object_id *oid)
 {
 	return sha1_to_hex(oid->hash);
diff --git a/sha1_name.c b/sha1_name.c
index da6874c..c58b477 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -368,14 +368,13 @@ int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 	return ds.ambiguous;
 }
 
-const char *find_unique_abbrev(const unsigned char *sha1, int len)
+int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 {
 	int status, exists;
-	static char hex[41];
 
-	memcpy(hex, sha1_to_hex(sha1), 40);
+	sha1_to_hex_r(hex, sha1);
 	if (len == 40 || !len)
-		return hex;
+		return 40;
 	exists = has_sha1_file(sha1);
 	while (len < 40) {
 		unsigned char sha1_ret[20];
@@ -384,10 +383,17 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
 		    ? !status
 		    : status == SHORT_NAME_NOT_FOUND) {
 			hex[len] = 0;
-			return hex;
+			return len;
 		}
 		len++;
 	}
+	return len;
+}
+
+const char *find_unique_abbrev(const unsigned char *sha1, int len)
+{
+	static char hex[GIT_SHA1_HEXSZ + 1];
+	find_unique_abbrev_r(hex, sha1, len);
 	return hex;
 }
 
diff --git a/strbuf.c b/strbuf.c
index 29df55b..f3c44fb 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -743,3 +743,12 @@ void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
 	}
 	strbuf_setlen(sb, sb->len + len);
 }
+
+void strbuf_add_unique_abbrev(struct strbuf *sb, const unsigned char *sha1,
+			      int abbrev_len)
+{
+	int r;
+	strbuf_grow(sb, GIT_SHA1_HEXSZ + 1);
+	r = find_unique_abbrev_r(sb->buf + sb->len, sha1, abbrev_len);
+	strbuf_setlen(sb, sb->len + r);
+}
diff --git a/strbuf.h b/strbuf.h
index 43f27c3..0f9c8a7 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -475,6 +475,14 @@ static inline struct strbuf **strbuf_split(const struct strbuf *sb,
 extern void strbuf_list_free(struct strbuf **);
 
 /**
+ * Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
+ * the strbuf `sb`.
+ */
+extern void strbuf_add_unique_abbrev(struct strbuf *sb,
+				     const unsigned char *sha1,
+				     int abbrev_len);
+
+/**
  * Launch the user preferred editor to edit a file and fill the buffer
  * with the file's contents upon the user completing their editing. The
  * third argument can be used to set the environment which the editor is
-- 
2.6.0.rc3.454.g204ad51

[PATCH 09/68] fsck: use strbuf to generate alternate directories

[Jeff King]

When fsck-ing alternates, we make a copy of the alternate
directory in a fixed PATH_MAX buffer. We memcpy directly,
without any check whether we are overflowing the buffer.
This is OK if PATH_MAX is a true representation of the
maximum path on the system, because any path here will have
already been vetted by the alternates subsystem. But that is
not true on every system, so we should be more careful.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fsck.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 46c7235..a019f4a 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -683,11 +683,12 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 
 		prepare_alt_odb();
 		for (alt = alt_odb_list; alt; alt = alt->next) {
-			char namebuf[PATH_MAX];
-			int namelen = alt->name - alt->base;
-			memcpy(namebuf, alt->base, namelen);
-			namebuf[namelen - 1] = 0;
-			fsck_object_dir(namebuf);
+			/* directory name, minus trailing slash */
+			size_t namelen = alt->name - alt->base - 1;
+			struct strbuf name = STRBUF_INIT;
+			strbuf_add(&name, alt->base, namelen);
+			fsck_object_dir(name.buf);
+			strbuf_release(&name);
 		}
 	}
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 10/68] mailsplit: make PATH_MAX buffers dynamic

[Jeff King]

There are several PATH_MAX-sized buffers in mailsplit, along
with some questionable uses of sprintf.  These are not
really of security interest, as local mailsplit pathnames
are not typically under control of an attacker, and you
could generally only overflow a few numbers at the end of a
path that approaches PATH_MAX (a longer path would choke
mailsplit long before). But it does not hurt to be careful,
and as a bonus we lift some limits for systems with
too-small PATH_MAX varibles.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/mailsplit.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/builtin/mailsplit.c b/builtin/mailsplit.c
index 9de06e3..104277a 100644
--- a/builtin/mailsplit.c
+++ b/builtin/mailsplit.c
@@ -98,30 +98,37 @@ static int populate_maildir_list(struct string_list *list, const char *path)
 {
 	DIR *dir;
 	struct dirent *dent;
-	char name[PATH_MAX];
+	char *name = NULL;
 	char *subs[] = { "cur", "new", NULL };
 	char **sub;
+	int ret = -1;
 
 	for (sub = subs; *sub; ++sub) {
-		snprintf(name, sizeof(name), "%s/%s", path, *sub);
+		free(name);
+		name = xstrfmt("%s/%s", path, *sub);
 		if ((dir = opendir(name)) == NULL) {
 			if (errno == ENOENT)
 				continue;
 			error("cannot opendir %s (%s)", name, strerror(errno));
-			return -1;
+			goto out;
 		}
 
 		while ((dent = readdir(dir)) != NULL) {
 			if (dent->d_name[0] == '.')
 				continue;
-			snprintf(name, sizeof(name), "%s/%s", *sub, dent->d_name);
+			free(name);
+			name = xstrfmt("%s/%s", *sub, dent->d_name);
 			string_list_insert(list, name);
 		}
 
 		closedir(dir);
 	}
 
-	return 0;
+	ret = 0;
+
+out:
+	free(name);
+	return ret;
 }
 
 static int maildir_filename_cmp(const char *a, const char *b)
@@ -148,8 +155,7 @@ static int maildir_filename_cmp(const char *a, const char *b)
 static int split_maildir(const char *maildir, const char *dir,
 	int nr_prec, int skip)
 {
-	char file[PATH_MAX];
-	char name[PATH_MAX];
+	char *file = NULL;
 	FILE *f = NULL;
 	int ret = -1;
 	int i;
@@ -161,7 +167,11 @@ static int split_maildir(const char *maildir, const char *dir,
 		goto out;
 
 	for (i = 0; i < list.nr; i++) {
-		snprintf(file, sizeof(file), "%s/%s", maildir, list.items[i].string);
+		char *name;
+
+		free(file);
+		file = xstrfmt("%s/%s", maildir, list.items[i].string);
+
 		f = fopen(file, "r");
 		if (!f) {
 			error("cannot open mail %s (%s)", file, strerror(errno));
@@ -173,8 +183,9 @@ static int split_maildir(const char *maildir, const char *dir,
 			goto out;
 		}
 
-		sprintf(name, "%s/%0*d", dir, nr_prec, ++skip);
+		name = xstrfmt("%s/%0*d", dir, nr_prec, ++skip);
 		split_one(f, name, 1);
+		free(name);
 
 		fclose(f);
 		f = NULL;
@@ -184,6 +195,7 @@ static int split_maildir(const char *maildir, const char *dir,
 out:
 	if (f)
 		fclose(f);
+	free(file);
 	string_list_clear(&list, 1);
 	return ret;
 }
@@ -191,7 +203,6 @@ out:
 static int split_mbox(const char *file, const char *dir, int allow_bare,
 		      int nr_prec, int skip)
 {
-	char name[PATH_MAX];
 	int ret = -1;
 	int peek;
 
@@ -218,8 +229,9 @@ static int split_mbox(const char *file, const char *dir, int allow_bare,
 	}
 
 	while (!file_done) {
-		sprintf(name, "%s/%0*d", dir, nr_prec, ++skip);
+		char *name = xstrfmt("%s/%0*d", dir, nr_prec, ++skip);
 		file_done = split_one(f, name, allow_bare);
+		free(name);
 	}
 
 	if (f != stdin)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 11/68] trace: use strbuf for quote_crnl output

[Jeff King]

When we output GIT_TRACE_SETUP paths, we quote any
meta-characters. But our buffer to hold the result is only
PATH_MAX bytes, and we could double the size of the input
path (if every character needs quoting). We could use a
2*PATH_MAX buffer, if we assume the input will never be more
than PATH_MAX. But it's easier still to just switch to a
strbuf and not worry about whether the input can exceed
PATH_MAX or not.

The original copied the "p2" pointer to "p1", advancing
both. Since this gets rid of "p1", let's also drop "p2",
whose name is now confusing. We can just advance the
original "path" pointer.

Signed-off-by: Jeff King <peff@peff.net>
---
 trace.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/trace.c b/trace.c
index 7393926..4aeea60 100644
--- a/trace.c
+++ b/trace.c
@@ -277,25 +277,24 @@ void trace_performance_fl(const char *file, int line, uint64_t nanos,
 
 static const char *quote_crnl(const char *path)
 {
-	static char new_path[PATH_MAX];
-	const char *p2 = path;
-	char *p1 = new_path;
+	static struct strbuf new_path = STRBUF_INIT;
 
 	if (!path)
 		return NULL;
 
-	while (*p2) {
-		switch (*p2) {
-		case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
-		case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
-		case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
+	strbuf_reset(&new_path);
+
+	while (*path) {
+		switch (*path) {
+		case '\\': strbuf_addstr(&new_path, "\\\\"); break;
+		case '\n': strbuf_addstr(&new_path, "\\n"); break;
+		case '\r': strbuf_addstr(&new_path, "\\r"); break;
 		default:
-			*p1++ = *p2;
+			strbuf_addch(&new_path, *path);
 		}
-		p2++;
+		path++;
 	}
-	*p1 = '\0';
-	return new_path;
+	return new_path.buf;
 }
 
 /* FIXME: move prefix to startup_info struct and get rid of this arg */
-- 
2.6.0.rc3.454.g204ad51

[PATCH 12/68] progress: store throughput display in a strbuf

[Jeff King]

Coverity noticed that we strncpy() into a fixed-size buffer
without making sure that it actually ended up
NUL-terminated. This is unlikely to be a bug in practice,
since throughput strings rarely hit 32 characters, but it
would be nice to clean it up.

The most obvious way to do so is to add a NUL-terminator.
But instead, this patch switches the fixed-size buffer out
for a strbuf. At first glance this seems much less
efficient, until we realize that filling in the fixed-size
buffer is done by writing into a strbuf and copying the
result!

By writing straight to the buffer, we actually end up more
efficient:

  1. We avoid an extra copy of the bytes.

  2. Rather than malloc/free each time progress is shown, we
     can strbuf_reset and use the same buffer each time.

Signed-off-by: Jeff King <peff@peff.net>
---
 progress.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/progress.c b/progress.c
index 2e31bec..a3efcfd 100644
--- a/progress.c
+++ b/progress.c
@@ -25,7 +25,7 @@ struct throughput {
 	unsigned int last_bytes[TP_IDX_MAX];
 	unsigned int last_misecs[TP_IDX_MAX];
 	unsigned int idx;
-	char display[32];
+	struct strbuf display;
 };
 
 struct progress {
@@ -98,7 +98,7 @@ static int display(struct progress *progress, unsigned n, const char *done)
 	}
 
 	progress->last_value = n;
-	tp = (progress->throughput) ? progress->throughput->display : "";
+	tp = (progress->throughput) ? progress->throughput->display.buf : "";
 	eol = done ? done : "   \r";
 	if (progress->total) {
 		unsigned percent = n * 100 / progress->total;
@@ -129,6 +129,7 @@ static int display(struct progress *progress, unsigned n, const char *done)
 static void throughput_string(struct strbuf *buf, off_t total,
 			      unsigned int rate)
 {
+	strbuf_reset(buf);
 	strbuf_addstr(buf, ", ");
 	strbuf_humanise_bytes(buf, total);
 	strbuf_addstr(buf, " | ");
@@ -141,7 +142,6 @@ void display_throughput(struct progress *progress, off_t total)
 	struct throughput *tp;
 	uint64_t now_ns;
 	unsigned int misecs, count, rate;
-	struct strbuf buf = STRBUF_INIT;
 
 	if (!progress)
 		return;
@@ -154,6 +154,7 @@ void display_throughput(struct progress *progress, off_t total)
 		if (tp) {
 			tp->prev_total = tp->curr_total = total;
 			tp->prev_ns = now_ns;
+			strbuf_init(&tp->display, 0);
 		}
 		return;
 	}
@@ -193,9 +194,7 @@ void display_throughput(struct progress *progress, off_t total)
 	tp->last_misecs[tp->idx] = misecs;
 	tp->idx = (tp->idx + 1) % TP_IDX_MAX;
 
-	throughput_string(&buf, total, rate);
-	strncpy(tp->display, buf.buf, sizeof(tp->display));
-	strbuf_release(&buf);
+	throughput_string(&tp->display, total, rate);
 	if (progress->last_value != -1 && progress_update)
 		display(progress, progress->last_value, NULL);
 }
@@ -250,12 +249,9 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 
 		bufp = (len < sizeof(buf)) ? buf : xmalloc(len + 1);
 		if (tp) {
-			struct strbuf strbuf = STRBUF_INIT;
 			unsigned int rate = !tp->avg_misecs ? 0 :
 					tp->avg_bytes / tp->avg_misecs;
-			throughput_string(&strbuf, tp->curr_total, rate);
-			strncpy(tp->display, strbuf.buf, sizeof(tp->display));
-			strbuf_release(&strbuf);
+			throughput_string(&tp->display, tp->curr_total, rate);
 		}
 		progress_update = 1;
 		sprintf(bufp, ", %s.\n", msg);
@@ -264,6 +260,8 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 			free(bufp);
 	}
 	clear_progress_signal();
+	if (progress->throughput)
+		strbuf_release(&progress->throughput->display);
 	free(progress->throughput);
 	free(progress);
 }
-- 
2.6.0.rc3.454.g204ad51

[PATCH 13/68] test-dump-cache-tree: avoid overflow of cache-tree name

[Jeff King]

When dumping a cache-tree, we sprintf sub-tree names directly
into a fixed-size buffer, which can overflow. We can
trivially fix this by converting to xsnprintf to at least
notice and die.

This probably should handle arbitrary-sized names, but
there's not much point. It's used only by the test scripts,
so the trivial fix is enough.

Signed-off-by: Jeff King <peff@peff.net>
---
 test-dump-cache-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-dump-cache-tree.c b/test-dump-cache-tree.c
index 54c0872..bb53c0a 100644
--- a/test-dump-cache-tree.c
+++ b/test-dump-cache-tree.c
@@ -47,7 +47,7 @@ static int dump_cache_tree(struct cache_tree *it,
 		struct cache_tree_sub *rdwn;
 
 		rdwn = cache_tree_sub(ref, down->name);
-		sprintf(path, "%s%.*s/", pfx, down->namelen, down->name);
+		xsnprintf(path, sizeof(path), "%s%.*s/", pfx, down->namelen, down->name);
 		if (dump_cache_tree(down->cache_tree, rdwn->cache_tree, path))
 			errs = 1;
 	}
-- 
2.6.0.rc3.454.g204ad51

[PATCH 14/68] compat/inet_ntop: fix off-by-one in inet_ntop4

[Jeff King]

Our compat inet_ntop4 function writes to a temporary buffer
with snprintf, and then uses strcpy to put the result into
the final "dst" buffer. We check the return value of
snprintf against the size of "dst", but fail to account for
the NUL terminator. As a result, we may overflow "dst" with
a single NUL. In practice, this doesn't happen because the
output of inet_ntop is limited, and we provide buffers that
are way oversized.

We can fix the off-by-one check easily, but while we are
here let's also use strlcpy for increased safety, just in
case there are other bugs lurking.

As a side note, this compat code seems to be BSD-derived.
Searching for "vixie inet_ntop" turns up NetBSD's latest
version of the same code, which has an identical fix (and
switches to strlcpy, too!).

Signed-off-by: Jeff King <peff@peff.net>
---
 compat/inet_ntop.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/compat/inet_ntop.c b/compat/inet_ntop.c
index 90b7cc4..6830726 100644
--- a/compat/inet_ntop.c
+++ b/compat/inet_ntop.c
@@ -53,11 +53,11 @@ inet_ntop4(const u_char *src, char *dst, size_t size)
 	nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
 	if (nprinted < 0)
 		return (NULL);	/* we assume "errno" was set by "snprintf()" */
-	if ((size_t)nprinted > size) {
+	if ((size_t)nprinted >= size) {
 		errno = ENOSPC;
 		return (NULL);
 	}
-	strcpy(dst, tmp);
+	strlcpy(dst, tmp, size);
 	return (dst);
 }
 
@@ -154,7 +154,7 @@ inet_ntop6(const u_char *src, char *dst, size_t size)
 		errno = ENOSPC;
 		return (NULL);
 	}
-	strcpy(dst, tmp);
+	strlcpy(dst, tmp, size);
 	return (dst);
 }
 #endif
-- 
2.6.0.rc3.454.g204ad51

[PATCH 15/68] convert trivial sprintf / strcpy calls to xsnprintf

[Jeff King]

We sometimes sprintf into fixed-size buffers when we know
that the buffer is large enough to fit the input (either
because it's a constant, or because it's numeric input that
is bounded in size). Likewise with strcpy of constant
strings.

However, these sites make it hard to audit sprintf and
strcpy calls for buffer overflows, as a reader has to
cross-reference the size of the array with the input. Let's
use xsnprintf instead, which communicates to a reader that
we don't expect this to overflow (and catches the mistake in
case we do).

Signed-off-by: Jeff King <peff@peff.net>
---
 archive-tar.c             |  2 +-
 builtin/gc.c              |  2 +-
 builtin/init-db.c         | 11 ++++++-----
 builtin/ls-tree.c         |  9 +++++----
 builtin/merge-index.c     |  2 +-
 builtin/merge-recursive.c |  2 +-
 builtin/read-tree.c       |  2 +-
 builtin/unpack-file.c     |  2 +-
 compat/mingw.c            |  8 +++++---
 compat/winansi.c          |  2 +-
 connect.c                 |  2 +-
 convert.c                 |  3 ++-
 daemon.c                  |  4 ++--
 diff.c                    | 12 ++++++------
 http-push.c               |  2 +-
 http.c                    |  6 +++---
 ll-merge.c                | 12 ++++++------
 refs.c                    |  8 ++++----
 sideband.c                |  4 ++--
 strbuf.c                  |  4 ++--
 20 files changed, 52 insertions(+), 47 deletions(-)

diff --git a/archive-tar.c b/archive-tar.c
index b6b30bb..d543f93 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -301,7 +301,7 @@ static int write_global_extended_header(struct archiver_args *args)
 	memset(&header, 0, sizeof(header));
 	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 	mode = 0100666;
-	strcpy(header.name, "pax_global_header");
+	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
 	prepare_header(args, &header, mode, ext_header.len);
 	write_blocked(&header, sizeof(header));
 	write_blocked(ext_header.buf, ext_header.len);
diff --git a/builtin/gc.c b/builtin/gc.c
index 0ad8d30..57584bc 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -194,7 +194,7 @@ static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 		return NULL;
 
 	if (gethostname(my_host, sizeof(my_host)))
-		strcpy(my_host, "unknown");
+		xsnprintf(my_host, sizeof(my_host), "unknown");
 
 	pidfile_path = git_pathdup("gc.pid");
 	fd = hold_lock_file_for_update(&lock, pidfile_path,
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 69323e1..e7d0e31 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -262,7 +262,8 @@ static int create_default_files(const char *template_path)
 	}
 
 	/* This forces creation of new config file */
-	sprintf(repo_version_string, "%d", GIT_REPO_VERSION);
+	xsnprintf(repo_version_string, sizeof(repo_version_string),
+		  "%d", GIT_REPO_VERSION);
 	git_config_set("core.repositoryformatversion", repo_version_string);
 
 	path[len] = 0;
@@ -414,13 +415,13 @@ int init_db(const char *template_dir, unsigned int flags)
 		 */
 		if (shared_repository < 0)
 			/* force to the mode value */
-			sprintf(buf, "0%o", -shared_repository);
+			xsnprintf(buf, sizeof(buf), "0%o", -shared_repository);
 		else if (shared_repository == PERM_GROUP)
-			sprintf(buf, "%d", OLD_PERM_GROUP);
+			xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_GROUP);
 		else if (shared_repository == PERM_EVERYBODY)
-			sprintf(buf, "%d", OLD_PERM_EVERYBODY);
+			xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 		else
-			die("oops");
+			die("BUG: invalid value for shared_repository");
 		git_config_set("core.sharedrepository", buf);
 		git_config_set("receive.denyNonFastforwards", "true");
 	}
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index 3b04a0f..0e30d86 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -96,12 +96,13 @@ static int show_tree(const unsigned char *sha1, struct strbuf *base,
 			if (!strcmp(type, blob_type)) {
 				unsigned long size;
 				if (sha1_object_info(sha1, &size) == OBJ_BAD)
-					strcpy(size_text, "BAD");
+					xsnprintf(size_text, sizeof(size_text),
+						  "BAD");
 				else
-					snprintf(size_text, sizeof(size_text),
-						 "%lu", size);
+					xsnprintf(size_text, sizeof(size_text),
+						  "%lu", size);
 			} else
-				strcpy(size_text, "-");
+				xsnprintf(size_text, sizeof(size_text), "-");
 			printf("%06o %s %s %7s\t", mode, type,
 			       find_unique_abbrev(sha1, abbrev),
 			       size_text);
diff --git a/builtin/merge-index.c b/builtin/merge-index.c
index 1a1eafa..1d66111 100644
--- a/builtin/merge-index.c
+++ b/builtin/merge-index.c
@@ -23,7 +23,7 @@ static int merge_entry(int pos, const char *path)
 			break;
 		found++;
 		strcpy(hexbuf[stage], sha1_to_hex(ce->sha1));
-		sprintf(ownbuf[stage], "%o", ce->ce_mode);
+		xsnprintf(ownbuf[stage], sizeof(ownbuf[stage]), "%o", ce->ce_mode);
 		arguments[stage] = hexbuf[stage];
 		arguments[stage + 4] = ownbuf[stage];
 	} while (++pos < active_nr);
diff --git a/builtin/merge-recursive.c b/builtin/merge-recursive.c
index a90f28f..491efd5 100644
--- a/builtin/merge-recursive.c
+++ b/builtin/merge-recursive.c
@@ -14,7 +14,7 @@ static const char *better_branch_name(const char *branch)
 
 	if (strlen(branch) != 40)
 		return branch;
-	sprintf(githead_env, "GITHEAD_%s", branch);
+	xsnprintf(githead_env, sizeof(githead_env), "GITHEAD_%s", branch);
 	name = getenv(githead_env);
 	return name ? name : branch;
 }
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 2379e11..8c693e7 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -90,7 +90,7 @@ static int debug_merge(const struct cache_entry * const *stages,
 	debug_stage("index", stages[0], o);
 	for (i = 1; i <= o->merge_size; i++) {
 		char buf[24];
-		sprintf(buf, "ent#%d", i);
+		xsnprintf(buf, sizeof(buf), "ent#%d", i);
 		debug_stage(buf, stages[i], o);
 	}
 	return 0;
diff --git a/builtin/unpack-file.c b/builtin/unpack-file.c
index 1920029..6fc6bcd 100644
--- a/builtin/unpack-file.c
+++ b/builtin/unpack-file.c
@@ -12,7 +12,7 @@ static char *create_temp_file(unsigned char *sha1)
 	if (!buf || type != OBJ_BLOB)
 		die("unable to read blob object %s", sha1_to_hex(sha1));
 
-	strcpy(path, ".merge_file_XXXXXX");
+	xsnprintf(path, sizeof(path), ".merge_file_XXXXXX");
 	fd = xmkstemp(path);
 	if (write_in_full(fd, buf, size) != size)
 		die_errno("unable to write temp-file");
diff --git a/compat/mingw.c b/compat/mingw.c
index f74da23..a168800 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2133,9 +2133,11 @@ int uname(struct utsname *buf)
 {
 	DWORD v = GetVersion();
 	memset(buf, 0, sizeof(*buf));
-	strcpy(buf->sysname, "Windows");
-	sprintf(buf->release, "%u.%u", v & 0xff, (v >> 8) & 0xff);
+	xsnprintf(buf->sysname, sizeof(buf->sysname), "Windows");
+	xsnprintf(buf->release, sizeof(buf->release),
+		 "%u.%u", v & 0xff, (v >> 8) & 0xff);
 	/* assuming NT variants only.. */
-	sprintf(buf->version, "%u", (v >> 16) & 0x7fff);
+	xsnprintf(buf->version, sizeof(buf->version),
+		  "%u", (v >> 16) & 0x7fff);
 	return 0;
 }
diff --git a/compat/winansi.c b/compat/winansi.c
index efc5bb3..ceff55b 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -539,7 +539,7 @@ void winansi_init(void)
 		return;
 
 	/* create a named pipe to communicate with the console thread */
-	sprintf(name, "\\\\.\\pipe\\winansi%lu", GetCurrentProcessId());
+	xsnprintf(name, sizeof(name), "\\\\.\\pipe\\winansi%lu", GetCurrentProcessId());
 	hwrite = CreateNamedPipe(name, PIPE_ACCESS_OUTBOUND,
 		PIPE_TYPE_BYTE | PIPE_WAIT, 1, BUFFER_SIZE, 0, 0, NULL);
 	if (hwrite == INVALID_HANDLE_VALUE)
diff --git a/connect.c b/connect.c
index c0144d8..1d5c5e0 100644
--- a/connect.c
+++ b/connect.c
@@ -332,7 +332,7 @@ static const char *ai_name(const struct addrinfo *ai)
 	static char addr[NI_MAXHOST];
 	if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 			NI_NUMERICHOST) != 0)
-		strcpy(addr, "(unknown)");
+		xsnprintf(addr, sizeof(addr), "(unknown)");
 
 	return addr;
 }
diff --git a/convert.c b/convert.c
index f3bd3e9..814e814 100644
--- a/convert.c
+++ b/convert.c
@@ -1289,7 +1289,8 @@ static struct stream_filter *ident_filter(const unsigned char *sha1)
 {
 	struct ident_filter *ident = xmalloc(sizeof(*ident));
 
-	sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
+	xsnprintf(ident->ident, sizeof(ident->ident),
+		  ": %s $", sha1_to_hex(sha1));
 	strbuf_init(&ident->left, 0);
 	ident->filter.vtbl = &ident_vtbl;
 	ident->state = 0;
diff --git a/daemon.c b/daemon.c
index f9eb296..5218a3f 100644
--- a/daemon.c
+++ b/daemon.c
@@ -901,7 +901,7 @@ static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 		inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 		break;
 	default:
-		strcpy(ip, "<unknown>");
+		xsnprintf(ip, sizeof(ip), "<unknown>");
 	}
 	return ip;
 }
@@ -916,7 +916,7 @@ static int setup_named_sock(char *listen_addr, int listen_port, struct socketlis
 	int gai;
 	long flags;
 
-	sprintf(pbuf, "%d", listen_port);
+	xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = AF_UNSPEC;
 	hints.ai_socktype = SOCK_STREAM;
diff --git a/diff.c b/diff.c
index 08508f6..788e371 100644
--- a/diff.c
+++ b/diff.c
@@ -2880,7 +2880,7 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 	temp->name = get_tempfile_path(&temp->tempfile);
 	strcpy(temp->hex, sha1_to_hex(sha1));
 	temp->hex[40] = 0;
-	sprintf(temp->mode, "%06o", mode);
+	xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
 	strbuf_release(&buf);
 	strbuf_release(&template);
 	free(path_dup);
@@ -2897,8 +2897,8 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 		 * a '+' entry produces this for file-1.
 		 */
 		temp->name = "/dev/null";
-		strcpy(temp->hex, ".");
-		strcpy(temp->mode, ".");
+		xsnprintf(temp->hex, sizeof(temp->hex), ".");
+		xsnprintf(temp->mode, sizeof(temp->mode), ".");
 		return temp;
 	}
 
@@ -2935,7 +2935,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 			 * !(one->sha1_valid), as long as
 			 * DIFF_FILE_VALID(one).
 			 */
-			sprintf(temp->mode, "%06o", one->mode);
+			xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
 		}
 		return temp;
 	}
@@ -4081,9 +4081,9 @@ const char *diff_unique_abbrev(const unsigned char *sha1, int len)
 	if (abblen < 37) {
 		static char hex[41];
 		if (len < abblen && abblen <= len + 2)
-			sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
+			xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
 		else
-			sprintf(hex, "%s...", abbrev);
+			xsnprintf(hex, sizeof(hex), "%s...", abbrev);
 		return hex;
 	}
 	return sha1_to_hex(sha1);
diff --git a/http-push.c b/http-push.c
index c98dad2..154e67b 100644
--- a/http-push.c
+++ b/http-push.c
@@ -881,7 +881,7 @@ static struct remote_lock *lock_remote(const char *path, long timeout)
 	strbuf_addf(&out_buffer.buf, LOCK_REQUEST, escaped);
 	free(escaped);
 
-	sprintf(timeout_header, "Timeout: Second-%ld", timeout);
+	xsnprintf(timeout_header, sizeof(timeout_header), "Timeout: Second-%ld", timeout);
 	dav_headers = curl_slist_append(dav_headers, timeout_header);
 	dav_headers = curl_slist_append(dav_headers, "Content-Type: text/xml");
 
diff --git a/http.c b/http.c
index 9dce380..7b02259 100644
--- a/http.c
+++ b/http.c
@@ -1104,7 +1104,7 @@ static void write_accept_language(struct strbuf *buf)
 		     decimal_places++, max_q *= 10)
 			;
 
-		sprintf(q_format, ";q=0.%%0%dd", decimal_places);
+		xsnprintf(q_format, sizeof(q_format), ";q=0.%%0%dd", decimal_places);
 
 		strbuf_addstr(buf, "Accept-Language: ");
 
@@ -1601,7 +1601,7 @@ struct http_pack_request *new_http_pack_request(
 			fprintf(stderr,
 				"Resuming fetch of pack %s at byte %ld\n",
 				sha1_to_hex(target->sha1), prev_posn);
-		sprintf(range, "Range: bytes=%ld-", prev_posn);
+		xsnprintf(range, sizeof(range), "Range: bytes=%ld-", prev_posn);
 		preq->range_header = curl_slist_append(NULL, range);
 		curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
 			preq->range_header);
@@ -1761,7 +1761,7 @@ struct http_object_request *new_http_object_request(const char *base_url,
 			fprintf(stderr,
 				"Resuming fetch of object %s at byte %ld\n",
 				hex, prev_posn);
-		sprintf(range, "Range: bytes=%ld-", prev_posn);
+		xsnprintf(range, sizeof(range), "Range: bytes=%ld-", prev_posn);
 		range_header = curl_slist_append(range_header, range);
 		curl_easy_setopt(freq->slot->curl,
 				 CURLOPT_HTTPHEADER, range_header);
diff --git a/ll-merge.c b/ll-merge.c
index fc3c049..56f73b3 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -142,11 +142,11 @@ static struct ll_merge_driver ll_merge_drv[] = {
 	{ "union", "built-in union merge", ll_union_merge },
 };
 
-static void create_temp(mmfile_t *src, char *path)
+static void create_temp(mmfile_t *src, char *path, size_t len)
 {
 	int fd;
 
-	strcpy(path, ".merge_file_XXXXXX");
+	xsnprintf(path, len, ".merge_file_XXXXXX");
 	fd = xmkstemp(path);
 	if (write_in_full(fd, src->ptr, src->size) != src->size)
 		die_errno("unable to write temp-file");
@@ -187,10 +187,10 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
 
 	result->ptr = NULL;
 	result->size = 0;
-	create_temp(orig, temp[0]);
-	create_temp(src1, temp[1]);
-	create_temp(src2, temp[2]);
-	sprintf(temp[3], "%d", marker_size);
+	create_temp(orig, temp[0], sizeof(temp[0]));
+	create_temp(src1, temp[1], sizeof(temp[1]));
+	create_temp(src2, temp[2], sizeof(temp[2]));
+	xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
 
 	strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
 
diff --git a/refs.c b/refs.c
index 4e15f60..d5c8b2f 100644
--- a/refs.c
+++ b/refs.c
@@ -3326,10 +3326,10 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	msglen = msg ? strlen(msg) : 0;
 	maxlen = strlen(committer) + msglen + 100;
 	logrec = xmalloc(maxlen);
-	len = sprintf(logrec, "%s %s %s\n",
-		      sha1_to_hex(old_sha1),
-		      sha1_to_hex(new_sha1),
-		      committer);
+	len = xsnprintf(logrec, maxlen, "%s %s %s\n",
+			sha1_to_hex(old_sha1),
+			sha1_to_hex(new_sha1),
+			committer);
 	if (msglen)
 		len += copy_msg(logrec + len - 1, msg) - 1;
 
diff --git a/sideband.c b/sideband.c
index 7f9dc22..fde8adc 100644
--- a/sideband.c
+++ b/sideband.c
@@ -137,11 +137,11 @@ ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet
 		if (packet_max - 5 < n)
 			n = packet_max - 5;
 		if (0 <= band) {
-			sprintf(hdr, "%04x", n + 5);
+			xsnprintf(hdr, sizeof(hdr), "%04x", n + 5);
 			hdr[4] = band;
 			write_or_die(fd, hdr, 5);
 		} else {
-			sprintf(hdr, "%04x", n + 4);
+			xsnprintf(hdr, sizeof(hdr), "%04x", n + 4);
 			write_or_die(fd, hdr, 4);
 		}
 		write_or_die(fd, p, n);
diff --git a/strbuf.c b/strbuf.c
index f3c44fb..107c45d 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -245,8 +245,8 @@ void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size
 	static char prefix2[2];
 
 	if (prefix1[0] != comment_line_char) {
-		sprintf(prefix1, "%c ", comment_line_char);
-		sprintf(prefix2, "%c", comment_line_char);
+		xsnprintf(prefix1, sizeof(prefix1), "%c ", comment_line_char);
+		xsnprintf(prefix2, sizeof(prefix2), "%c", comment_line_char);
 	}
 	add_lines(out, prefix1, prefix2, buf, size);
 }
-- 
2.6.0.rc3.454.g204ad51

[PATCH 16/68] archive-tar: use xsnprintf for trivial formatting

[Jeff King]

When we generate tar headers, we sprintf() values directly
into a struct with the fixed-size header values. For the
most part this is fine, as we are formatting small values
(e.g., the octal format of "mode & 0x7777" is of fixed
length). But it's still a good idea to use xsnprintf here.
It communicates to readers what our expectation is, and it
provides a run-time check that we are not overflowing the
buffers.

The one exception here is the mtime, which comes from the
epoch time of the commit we are archiving. For sane values,
this fits into the 12-byte value allocated in the header.
But since git can handle 64-bit times, if I claim to be a
visitor from the year 10,000 AD, I can overflow the buffer.
This turns out to be harmless, as we simply overflow into
the chksum field, which is then overwritten.

This case is also best as an xsnprintf. It should never come
up, short of extremely malformed dates, and in that case we
are probably better off dying than silently truncating the
date value (and we cannot expand the size of the buffer,
since it is dictated by the ustar format). Our friends in
the year 5138 (when we legitimately flip to a 12-digit
epoch) can deal with that problem then.

Signed-off-by: Jeff King <peff@peff.net>
---
 archive-tar.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/archive-tar.c b/archive-tar.c
index d543f93..501ca97 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -167,21 +167,21 @@ static void prepare_header(struct archiver_args *args,
 			   struct ustar_header *header,
 			   unsigned int mode, unsigned long size)
 {
-	sprintf(header->mode, "%07o", mode & 07777);
-	sprintf(header->size, "%011lo", S_ISREG(mode) ? size : 0);
-	sprintf(header->mtime, "%011lo", (unsigned long) args->time);
+	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
+	xsnprintf(header->size, sizeof(header->size), "%011lo", S_ISREG(mode) ? size : 0);
+	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
 
-	sprintf(header->uid, "%07o", 0);
-	sprintf(header->gid, "%07o", 0);
+	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
+	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
 	strlcpy(header->uname, "root", sizeof(header->uname));
 	strlcpy(header->gname, "root", sizeof(header->gname));
-	sprintf(header->devmajor, "%07o", 0);
-	sprintf(header->devminor, "%07o", 0);
+	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
+	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
 
 	memcpy(header->magic, "ustar", 6);
 	memcpy(header->version, "00", 2);
 
-	sprintf(header->chksum, "%07o", ustar_header_chksum(header));
+	snprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
 }
 
 static int write_extended_header(struct archiver_args *args,
@@ -193,7 +193,7 @@ static int write_extended_header(struct archiver_args *args,
 	memset(&header, 0, sizeof(header));
 	*header.typeflag = TYPEFLAG_EXT_HEADER;
 	mode = 0100666;
-	sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
+	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", sha1_to_hex(sha1));
 	prepare_header(args, &header, mode, size);
 	write_blocked(&header, sizeof(header));
 	write_blocked(buffer, size);
@@ -235,8 +235,8 @@ static int write_tar_entry(struct archiver_args *args,
 			memcpy(header.prefix, path, plen);
 			memcpy(header.name, path + plen + 1, rest);
 		} else {
-			sprintf(header.name, "%s.data",
-				sha1_to_hex(sha1));
+			xsnprintf(header.name, sizeof(header.name), "%s.data",
+				  sha1_to_hex(sha1));
 			strbuf_append_ext_header(&ext_header, "path",
 						 path, pathlen);
 		}
@@ -259,8 +259,8 @@ static int write_tar_entry(struct archiver_args *args,
 
 	if (S_ISLNK(mode)) {
 		if (size > sizeof(header.linkname)) {
-			sprintf(header.linkname, "see %s.paxheader",
-			        sha1_to_hex(sha1));
+			xsnprintf(header.linkname, sizeof(header.linkname),
+				  "see %s.paxheader", sha1_to_hex(sha1));
 			strbuf_append_ext_header(&ext_header, "linkpath",
 			                         buffer, size);
 		} else
-- 
2.6.0.rc3.454.g204ad51

[PATCH 17/68] use xsnprintf for generating git object headers

[Jeff King]

We generally use 32-byte buffers to format git's "type size"
header fields. These should not generally overflow unless
you can produce some truly gigantic objects (and our types
come from our internal array of constant strings). But it is
a good idea to use xsnprintf to make sure this is the case.

Note that we slightly modify the interface to
write_sha1_file_prepare, which nows uses "hdrlen" as an "in"
parameter as well as an "out" (on the way in it stores the
allocated size of the header, and on the way out it returns
the ultimate size of the header).

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/index-pack.c |  2 +-
 bulk-checkin.c       |  4 ++--
 fast-import.c        |  4 ++--
 http-push.c          |  2 +-
 sha1_file.c          | 13 +++++++------
 5 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 3431de2..1ad1bde 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -441,7 +441,7 @@ static void *unpack_entry_data(unsigned long offset, unsigned long size,
 	int hdrlen;
 
 	if (!is_delta_type(type)) {
-		hdrlen = sprintf(hdr, "%s %lu", typename(type), size) + 1;
+		hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), size) + 1;
 		git_SHA1_Init(&c);
 		git_SHA1_Update(&c, hdr, hdrlen);
 	} else
diff --git a/bulk-checkin.c b/bulk-checkin.c
index 7cffc3a..4347f5c 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -200,8 +200,8 @@ static int deflate_to_pack(struct bulk_checkin_state *state,
 	if (seekback == (off_t) -1)
 		return error("cannot find the current offset");
 
-	header_len = sprintf((char *)obuf, "%s %" PRIuMAX,
-			     typename(type), (uintmax_t)size) + 1;
+	header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
+			       typename(type), (uintmax_t)size) + 1;
 	git_SHA1_Init(&ctx);
 	git_SHA1_Update(&ctx, obuf, header_len);
 
diff --git a/fast-import.c b/fast-import.c
index 6c7c3c9..d0c2502 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1035,8 +1035,8 @@ static int store_object(
 	git_SHA_CTX c;
 	git_zstream s;
 
-	hdrlen = sprintf((char *)hdr,"%s %lu", typename(type),
-		(unsigned long)dat->len) + 1;
+	hdrlen = xsnprintf((char *)hdr, sizeof(hdr), "%s %lu",
+			   typename(type), (unsigned long)dat->len) + 1;
 	git_SHA1_Init(&c);
 	git_SHA1_Update(&c, hdr, hdrlen);
 	git_SHA1_Update(&c, dat->buf, dat->len);
diff --git a/http-push.c b/http-push.c
index 154e67b..1f3788f 100644
--- a/http-push.c
+++ b/http-push.c
@@ -361,7 +361,7 @@ static void start_put(struct transfer_request *request)
 	git_zstream stream;
 
 	unpacked = read_sha1_file(request->obj->sha1, &type, &len);
-	hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
+	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
 
 	/* Set it up */
 	git_deflate_init(&stream, zlib_compression_level);
diff --git a/sha1_file.c b/sha1_file.c
index d295a32..f106091 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1464,7 +1464,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 		return -1;
 
 	/* Generate the header */
-	hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1;
+	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 
 	/* Sha1.. */
 	git_SHA1_Init(&c);
@@ -2930,7 +2930,7 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
 	git_SHA_CTX c;
 
 	/* Generate the header */
-	*hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
+	*hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
 
 	/* Sha1.. */
 	git_SHA1_Init(&c);
@@ -2993,7 +2993,7 @@ int hash_sha1_file(const void *buf, unsigned long len, const char *type,
                    unsigned char *sha1)
 {
 	char hdr[32];
-	int hdrlen;
+	int hdrlen = sizeof(hdr);
 	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
 	return 0;
 }
@@ -3139,7 +3139,7 @@ static int freshen_packed_object(const unsigned char *sha1)
 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
 {
 	char hdr[32];
-	int hdrlen;
+	int hdrlen = sizeof(hdr);
 
 	/* Normally if we have it in the pack then we do not bother writing
 	 * it out into .git/objects/??/?{38} file.
@@ -3157,7 +3157,8 @@ int hash_sha1_file_literally(const void *buf, unsigned long len, const char *typ
 	int hdrlen, status = 0;
 
 	/* type string, SP, %lu of the length plus NUL must fit this */
-	header = xmalloc(strlen(type) + 32);
+	hdrlen = strlen(type) + 32;
+	header = xmalloc(hdrlen);
 	write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
 
 	if (!(flags & HASH_WRITE_OBJECT))
@@ -3185,7 +3186,7 @@ int force_object_loose(const unsigned char *sha1, time_t mtime)
 	buf = read_packed_sha1(sha1, &type, &len);
 	if (!buf)
 		return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
-	hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
+	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
 	ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
 	free(buf);
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 18/68] find_short_object_filename: convert sprintf to xsnprintf

[Jeff King]

We use sprintf() to format some hex data into a buffer. The
buffer is clearly long enough, and using snprintf here is
not necessary. And in fact, it does not really make anything
easier to audit, as the size we feed to snprintf accounts
for the magic extra 42 bytes found in each alt->name field
of struct alternate_object_database (which is there exactly
to do this formatting).

Still, it is nice to remove an sprintf call and replace it
with an xsnprintf and explanatory comment, which makes it
easier to audit the code base for overflows.

Signed-off-by: Jeff King <peff@peff.net>
---
 sha1_name.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sha1_name.c b/sha1_name.c
index c58b477..80753b6 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -96,11 +96,15 @@ static void find_short_object_filename(int len, const char *hex_pfx, struct disa
 	}
 	fakeent->next = alt_odb_list;
 
-	sprintf(hex, "%.2s", hex_pfx);
+	xsnprintf(hex, sizeof(hex), "%.2s", hex_pfx);
 	for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 		struct dirent *de;
 		DIR *dir;
-		sprintf(alt->name, "%.2s/", hex_pfx);
+		/*
+		 * every alt_odb struct has 42 extra bytes after the base
+		 * for exactly this purpose
+		 */
+		xsnprintf(alt->name, 42, "%.2s/", hex_pfx);
 		dir = opendir(alt->base);
 		if (!dir)
 			continue;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 19/68] stop_progress_msg: convert sprintf to xsnprintf

[Jeff King]

The usual arguments for using xsnprintf over sprintf apply,
but this case is a little tricky. We print to a fixed-size
buffer if we have room, and otherwise to an allocated
buffer. So there should be no overflow here, but it is still
good to communicate our intention, as well as to check our
earlier math for how much space the string will need.

Signed-off-by: Jeff King <peff@peff.net>
---
 progress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/progress.c b/progress.c
index a3efcfd..353bd37 100644
--- a/progress.c
+++ b/progress.c
@@ -254,7 +254,7 @@ void stop_progress_msg(struct progress **p_progress, const char *msg)
 			throughput_string(&tp->display, tp->curr_total, rate);
 		}
 		progress_update = 1;
-		sprintf(bufp, ", %s.\n", msg);
+		xsnprintf(bufp, len + 1, ", %s.\n", msg);
 		display(progress, progress->last_value, bufp);
 		if (buf != bufp)
 			free(bufp);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 20/68] compat/hstrerror: convert sprintf to snprintf

[Jeff King]

This is a trivially correct use of sprintf, as our error
number should not be excessively long. But it's still nice
to drop an sprintf call.

Note that we cannot use xsnprintf here, because this is
compat code which does not load git-compat-util.h.

Signed-off-by: Jeff King <peff@peff.net>
---
 compat/hstrerror.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/hstrerror.c b/compat/hstrerror.c
index 069c555..b85a2fa 100644
--- a/compat/hstrerror.c
+++ b/compat/hstrerror.c
@@ -16,6 +16,6 @@ const char *githstrerror(int err)
 	case TRY_AGAIN:
 		return "Non-authoritative \"host not found\", or SERVERFAIL";
 	}
-	sprintf(buffer, "Name resolution error %d", err);
+	snprintf(buffer, sizeof(buffer), "Name resolution error %d", err);
 	return buffer;
 }
-- 
2.6.0.rc3.454.g204ad51

[PATCH 21/68] grep: use xsnprintf to format failure message

[Jeff King]

This looks at first glance like the sprintf can overflow our
buffer, but it's actually fine; the p->origin string is
something constant and small, like "command line" or "-e
option".

Signed-off-by: Jeff King <peff@peff.net>
---
 grep.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/grep.c b/grep.c
index b58c7c6..6c68d5b 100644
--- a/grep.c
+++ b/grep.c
@@ -306,9 +306,9 @@ static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 	char where[1024];
 
 	if (p->no)
-		sprintf(where, "In '%s' at %d, ", p->origin, p->no);
+		xsnprintf(where, sizeof(where), "In '%s' at %d, ", p->origin, p->no);
 	else if (p->origin)
-		sprintf(where, "%s, ", p->origin);
+		xsnprintf(where, sizeof(where), "%s, ", p->origin);
 	else
 		where[0] = 0;
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 22/68] entry.c: convert strcpy to xsnprintf

[Jeff King]

This particular conversion is non-obvious, because nobody
has passed our function the length of the destination
buffer. However, the interface to checkout_entry specifies
that the buffer must be at least TEMPORARY_FILENAME_LENGTH
bytes long, so we can check that (meaning the existing code
was not buggy, but merely worrisome to somebody reading it).

Signed-off-by: Jeff King <peff@peff.net>
---
 entry.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/entry.c b/entry.c
index 1eda8e9..582c400 100644
--- a/entry.c
+++ b/entry.c
@@ -96,8 +96,8 @@ static int open_output_fd(char *path, const struct cache_entry *ce, int to_tempf
 {
 	int symlink = (ce->ce_mode & S_IFMT) != S_IFREG;
 	if (to_tempfile) {
-		strcpy(path, symlink
-		       ? ".merge_link_XXXXXX" : ".merge_file_XXXXXX");
+		xsnprintf(path, TEMPORARY_FILENAME_LENGTH, "%s",
+			  symlink ? ".merge_link_XXXXXX" : ".merge_file_XXXXXX");
 		return mkstemp(path);
 	} else {
 		return create_file(path, !symlink ? ce->ce_mode : 0666);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 23/68] add_packed_git: convert strcpy into xsnprintf

[Jeff King]

We have the path "foo.idx", and we create a buffer big
enough to hold "foo.pack" and "foo.keep", and then strcpy
straight into it. This isn't a bug (we have enough space),
but it's very hard to tell from the strcpy that this is so.

Let's instead use strip_suffix to take off the ".idx",
record the size of our allocation, and use xsnprintf to make
sure we don't violate our assumptions.

Signed-off-by: Jeff King <peff@peff.net>
---
 cache.h     |  2 +-
 sha1_file.c | 21 +++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/cache.h b/cache.h
index 030b880..d206d64 100644
--- a/cache.h
+++ b/cache.h
@@ -1309,7 +1309,7 @@ extern void close_pack_windows(struct packed_git *);
 extern void unuse_pack(struct pack_window **);
 extern void free_pack_by_name(const char *);
 extern void clear_delta_base_cache(void);
-extern struct packed_git *add_packed_git(const char *, int, int);
+extern struct packed_git *add_packed_git(const char *path, size_t path_len, int local);
 
 /*
  * Return the SHA-1 of the nth object within the specified packfile.
diff --git a/sha1_file.c b/sha1_file.c
index f106091..592226e 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1146,11 +1146,12 @@ static void try_to_free_pack_memory(size_t size)
 	release_pack_memory(size);
 }
 
-struct packed_git *add_packed_git(const char *path, int path_len, int local)
+struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 {
 	static int have_set_try_to_free_routine;
 	struct stat st;
-	struct packed_git *p = alloc_packed_git(path_len + 2);
+	size_t alloc;
+	struct packed_git *p;
 
 	if (!have_set_try_to_free_routine) {
 		have_set_try_to_free_routine = 1;
@@ -1161,18 +1162,22 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 	 * Make sure a corresponding .pack file exists and that
 	 * the index looks sane.
 	 */
-	path_len -= strlen(".idx");
-	if (path_len < 1) {
-		free(p);
+	if (!strip_suffix_mem(path, &path_len, ".idx"))
 		return NULL;
-	}
+
+	/*
+	 * ".pack" is long enough to hold any suffix we're adding (and
+	 * the use xsnprintf double-checks that)
+	 */
+	alloc = path_len + strlen(".pack") + 1;
+	p = alloc_packed_git(alloc);
 	memcpy(p->pack_name, path, path_len);
 
-	strcpy(p->pack_name + path_len, ".keep");
+	xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 	if (!access(p->pack_name, F_OK))
 		p->pack_keep = 1;
 
-	strcpy(p->pack_name + path_len, ".pack");
+	xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 	if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 		free(p);
 		return NULL;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 24/68] http-push: replace strcat with xsnprintf

[Jeff King]

We account for these strcats in our initial allocation, but
the code is confusing to follow and verify. Let's remember
our original allocation length, and then xsnprintf can
verify that we don't exceed it.

Note that we can't just use xstrfmt here (which would be
even cleaner) because the code tries to grow the buffer only
when necessary.

Signed-off-by: Jeff King <peff@peff.net>
---
 http-push.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/http-push.c b/http-push.c
index 1f3788f..37baff8 100644
--- a/http-push.c
+++ b/http-push.c
@@ -786,21 +786,21 @@ xml_start_tag(void *userData, const char *name, const char **atts)
 {
 	struct xml_ctx *ctx = (struct xml_ctx *)userData;
 	const char *c = strchr(name, ':');
-	int new_len;
+	int old_namelen, new_len;
 
 	if (c == NULL)
 		c = name;
 	else
 		c++;
 
-	new_len = strlen(ctx->name) + strlen(c) + 2;
+	old_namelen = strlen(ctx->name);
+	new_len = old_namelen + strlen(c) + 2;
 
 	if (new_len > ctx->len) {
 		ctx->name = xrealloc(ctx->name, new_len);
 		ctx->len = new_len;
 	}
-	strcat(ctx->name, ".");
-	strcat(ctx->name, c);
+	xsnprintf(ctx->name + old_namelen, ctx->len - old_namelen, ".%s", c);
 
 	free(ctx->cdata);
 	ctx->cdata = NULL;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 25/68] receive-pack: convert strncpy to xsnprintf

[Jeff King]

This strncpy is pointless; we pass the strlen() of the src
string, meaning that it works just like a memcpy. Worse,
though, is that the size has no relation to the destination
buffer, meaning it is a potential overflow.  In practice,
it's not. We pass only short constant strings like
"warning: " and "error: ", which are much smaller than the
destination buffer.

We can make this much simpler by just using xsnprintf, which
will check for overflow and return the size for our next
vsnprintf, without us having to run a separate strlen().

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/receive-pack.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index e6b93d0..04d2bdf 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -280,10 +280,10 @@ static void rp_warning(const char *err, ...) __attribute__((format (printf, 1, 2
 
 static void report_message(const char *prefix, const char *err, va_list params)
 {
-	int sz = strlen(prefix);
+	int sz;
 	char msg[4096];
 
-	strncpy(msg, prefix, sz);
+	sz = xsnprintf(msg, sizeof(msg), "%s", prefix);
 	sz += vsnprintf(msg + sz, sizeof(msg) - sz, err, params);
 	if (sz > (sizeof(msg) - 1))
 		sz = sizeof(msg) - 1;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 26/68] replace trivial malloc + sprintf / strcpy calls with xstrfmt

[Jeff King]

It's a common pattern to do:

  foo = xmalloc(strlen(one) + strlen(two) + 1 + 1);
  sprintf(foo, "%s %s", one, two);

(or possibly some variant with strcpy()s or a more
complicated length computation).  We can switch these to use
xstrfmt, which is shorter, involves less error-prone manual
computation, and removes many sprintf and strcpy calls which
make it harder to audit the code for real buffer overflows.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/apply.c     |  5 +----
 builtin/ls-remote.c |  8 ++------
 builtin/name-rev.c  | 13 +++++--------
 environment.c       |  7 ++-----
 imap-send.c         |  5 ++---
 reflog-walk.c       |  7 +++----
 remote.c            |  7 +------
 setup.c             | 12 +++---------
 unpack-trees.c      |  4 +---
 9 files changed, 20 insertions(+), 48 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index 4aa53f7..094a20f 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -698,10 +698,7 @@ static char *find_name_common(const char *line, const char *def,
 	}
 
 	if (root) {
-		char *ret = xmalloc(root_len + len + 1);
-		strcpy(ret, root);
-		memcpy(ret + root_len, start, len);
-		ret[root_len + len] = '\0';
+		char *ret = xstrfmt("%s%.*s", root, len, start);
 		return squash_slash(ret);
 	}
 
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 4554dbc..5b6d679 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -93,12 +93,8 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 	if (argv[i]) {
 		int j;
 		pattern = xcalloc(argc - i + 1, sizeof(const char *));
-		for (j = i; j < argc; j++) {
-			int len = strlen(argv[j]);
-			char *p = xmalloc(len + 3);
-			sprintf(p, "*/%s", argv[j]);
-			pattern[j - i] = p;
-		}
+		for (j = i; j < argc; j++)
+			pattern[j - i] = xstrfmt("*/%s", argv[j]);
 	}
 	remote = remote_get(dest);
 	if (!remote) {
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 248a3eb..8a3a0cd 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -56,19 +56,16 @@ copy_data:
 			parents = parents->next, parent_number++) {
 		if (parent_number > 1) {
 			int len = strlen(tip_name);
-			char *new_name = xmalloc(len +
-				1 + decimal_length(generation) +  /* ~<n> */
-				1 + 2 +				  /* ^NN */
-				1);
+			char *new_name;
 
 			if (len > 2 && !strcmp(tip_name + len - 2, "^0"))
 				len -= 2;
 			if (generation > 0)
-				sprintf(new_name, "%.*s~%d^%d", len, tip_name,
-						generation, parent_number);
+				new_name = xstrfmt("%.*s~%d^%d", len, tip_name,
+						   generation, parent_number);
 			else
-				sprintf(new_name, "%.*s^%d", len, tip_name,
-						parent_number);
+				new_name = xstrfmt("%.*s^%d", len, tip_name,
+						   parent_number);
 
 			name_rev(parents->item, new_name, 0,
 				distance + MERGE_TRAVERSAL_WEIGHT, 0);
diff --git a/environment.c b/environment.c
index a533aed..c5b65f5 100644
--- a/environment.c
+++ b/environment.c
@@ -143,11 +143,8 @@ static char *git_path_from_env(const char *envvar, const char *git_dir,
 			       const char *path, int *fromenv)
 {
 	const char *value = getenv(envvar);
-	if (!value) {
-		char *buf = xmalloc(strlen(git_dir) + strlen(path) + 2);
-		sprintf(buf, "%s/%s", git_dir, path);
-		return buf;
-	}
+	if (!value)
+		return xstrfmt("%s/%s", git_dir, path);
 	if (fromenv)
 		*fromenv = 1;
 	return xstrdup(value);
diff --git a/imap-send.c b/imap-send.c
index 37ac4aa..e9faaea 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -889,9 +889,8 @@ static char *cram(const char *challenge_64, const char *user, const char *pass)
 	}
 
 	/* response: "<user> <digest in hex>" */
-	resp_len = strlen(user) + 1 + strlen(hex) + 1;
-	response = xmalloc(resp_len);
-	sprintf(response, "%s %s", user, hex);
+	response = xstrfmt("%s %s", user, hex);
+	resp_len = strlen(response) + 1;
 
 	response_64 = xmalloc(ENCODED_SIZE(resp_len) + 1);
 	encoded_len = EVP_EncodeBlock((unsigned char *)response_64,
diff --git a/reflog-walk.c b/reflog-walk.c
index f8e743a..85b8a54 100644
--- a/reflog-walk.c
+++ b/reflog-walk.c
@@ -56,12 +56,11 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 		}
 	}
 	if (reflogs->nr == 0) {
-		int len = strlen(ref);
-		char *refname = xmalloc(len + 12);
-		sprintf(refname, "refs/%s", ref);
+		char *refname = xstrfmt("refs/%s", ref);
 		for_each_reflog_ent(refname, read_one_reflog, reflogs);
 		if (reflogs->nr == 0) {
-			sprintf(refname, "refs/heads/%s", ref);
+			free(refname);
+			refname = xstrfmt("refs/heads/%s", ref);
 			for_each_reflog_ent(refname, read_one_reflog, reflogs);
 		}
 		free(refname);
diff --git a/remote.c b/remote.c
index 26504b7..5ab0f7f 100644
--- a/remote.c
+++ b/remote.c
@@ -65,7 +65,6 @@ static int valid_remote(const struct remote *remote)
 static const char *alias_url(const char *url, struct rewrites *r)
 {
 	int i, j;
-	char *ret;
 	struct counted_string *longest;
 	int longest_i;
 
@@ -86,11 +85,7 @@ static const char *alias_url(const char *url, struct rewrites *r)
 	if (!longest)
 		return url;
 
-	ret = xmalloc(r->rewrite[longest_i]->baselen +
-		     (strlen(url) - longest->len) + 1);
-	strcpy(ret, r->rewrite[longest_i]->base);
-	strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
-	return ret;
+	return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
 }
 
 static void add_push_refspec(struct remote *remote, const char *ref)
diff --git a/setup.c b/setup.c
index a17c51e..2b64cbb 100644
--- a/setup.c
+++ b/setup.c
@@ -99,10 +99,7 @@ char *prefix_path_gently(const char *prefix, int len,
 			return NULL;
 		}
 	} else {
-		sanitized = xmalloc(len + strlen(path) + 1);
-		if (len)
-			memcpy(sanitized, prefix, len);
-		strcpy(sanitized + len, path);
+		sanitized = xstrfmt("%.*s%s", len, prefix, path);
 		if (remaining_prefix)
 			*remaining_prefix = len;
 		if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
@@ -468,11 +465,8 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
 
 	if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 		size_t pathlen = slash+1 - path;
-		size_t dirlen = pathlen + len - 8;
-		dir = xmalloc(dirlen + 1);
-		strncpy(dir, path, pathlen);
-		strncpy(dir + pathlen, buf + 8, len - 8);
-		dir[dirlen] = '\0';
+		dir = xstrfmt("%.*s%.*s", (int)pathlen, path,
+			      (int)(len - 8), buf + 8);
 		free(buf);
 		buf = dir;
 	}
diff --git a/unpack-trees.c b/unpack-trees.c
index f932e80..8e2032f 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1350,9 +1350,7 @@ static int verify_clean_subdirectory(const struct cache_entry *ce,
 	 * Then we need to make sure that we do not lose a locally
 	 * present file that is not ignored.
 	 */
-	pathbuf = xmalloc(namelen + 2);
-	memcpy(pathbuf, ce->name, namelen);
-	strcpy(pathbuf+namelen, "/");
+	pathbuf = xstrfmt("%.*s/", namelen, ce->name);
 
 	memset(&d, 0, sizeof(d));
 	if (o->dir)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 27/68] config: use xstrfmt in normalize_value

[Jeff King]

We xmalloc a fixed-size buffer and sprintf into it; this is
OK because the size of our formatting types is finite, but
that's not immediately clear to a reader auditing sprintf
calls. Let's switch to xstrfmt, which is shorter and
obviously correct.

Note that just dropping the common xmalloc here causes gcc
to complain with -Wmaybe-uninitialized. That's because if
"types" does not match any of our known types, we never
write anything into the "normalized" pointer. With the
current code, gcc doesn't notice because we always return a
valid pointer (just one which might point to uninitialized
data, but the compiler doesn't know that). In other words,
the current code is potentially buggy if new types are added
without updating this spot.

So let's take this opportunity to clean up the function a
bit more. We can drop the "normalized" pointer entirely, and
just return directly from each code path. And then add an
assertion at the end in case we haven't covered any cases.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/config.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/builtin/config.c b/builtin/config.c
index 71acc44..adc7727 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -246,8 +246,6 @@ free_strings:
 
 static char *normalize_value(const char *key, const char *value)
 {
-	char *normalized;
-
 	if (!value)
 		return NULL;
 
@@ -258,27 +256,21 @@ static char *normalize_value(const char *key, const char *value)
 		 * "~/foobar/" in the config file, and to expand the ~
 		 * when retrieving the value.
 		 */
-		normalized = xstrdup(value);
-	else {
-		normalized = xmalloc(64);
-		if (types == TYPE_INT) {
-			int64_t v = git_config_int64(key, value);
-			sprintf(normalized, "%"PRId64, v);
-		}
-		else if (types == TYPE_BOOL)
-			sprintf(normalized, "%s",
-				git_config_bool(key, value) ? "true" : "false");
-		else if (types == TYPE_BOOL_OR_INT) {
-			int is_bool, v;
-			v = git_config_bool_or_int(key, value, &is_bool);
-			if (!is_bool)
-				sprintf(normalized, "%d", v);
-			else
-				sprintf(normalized, "%s", v ? "true" : "false");
-		}
+		return xstrdup(value);
+	if (types == TYPE_INT)
+		return xstrfmt("%"PRId64, git_config_int64(key, value));
+	if (types == TYPE_BOOL)
+		return xstrdup(git_config_bool(key, value) ?  "true" : "false");
+	if (types == TYPE_BOOL_OR_INT) {
+		int is_bool, v;
+		v = git_config_bool_or_int(key, value, &is_bool);
+		if (!is_bool)
+			return xstrfmt("%d", v);
+		else
+			return xstrdup(v ? "true" : "false");
 	}
 
-	return normalized;
+	die("BUG: cannot normalize type %d", types);
 }
 
 static int get_color_found;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 28/68] fetch: replace static buffer with xstrfmt

[Jeff King]

We parse the INFINITE_DEPTH constant into a static,
fixed-size buffer using sprintf. This buffer is sufficiently
large for the current constant, but it's a suspicious
pattern, as the constant is defined far away, and it's not
immediately obvious that 12 bytes are large enough to hold
it.

We can just use xstrfmt here, which gets rid of any question
of the buffer size. It also removes any concerns with object
lifetime, which means we do not have to wonder why this
buffer deep within a conditional is marked "static" (we
never free our newly allocated result, of course, but that's
OK; it's global that lasts the lifetime of the whole program
anyway).

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fetch.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 9a3869f..4703725 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1156,11 +1156,8 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 			die(_("--depth and --unshallow cannot be used together"));
 		else if (!is_repository_shallow())
 			die(_("--unshallow on a complete repository does not make sense"));
-		else {
-			static char inf_depth[12];
-			sprintf(inf_depth, "%d", INFINITE_DEPTH);
-			depth = inf_depth;
-		}
+		else
+			depth = xstrfmt("%d", INFINITE_DEPTH);
 	}
 
 	/* no need to be strict, transport_set_option() will validate it again */
-- 
2.6.0.rc3.454.g204ad51

[PATCH 29/68] use strip_suffix and xstrfmt to replace suffix

[Jeff King]

When we want to convert "foo.pack" to "foo.idx", we do it by
duplicating the original string and then munging the bytes
in place. Let's use strip_suffix and xstrfmt instead, which
has several advantages:

  1. It's more clear what the intent is.

  2. It does not implicitly rely on the fact that
     strlen(".idx") <= strlen(".pack") to avoid an overflow.

  3. We communicate the assumption that the input file ends
     with ".pack" (and get a run-time check that this is so).

  4. We drop calls to strcpy, which makes auditing the code
     base easier.

Likewise, we can do this to convert ".pack" to ".bitmap",
avoiding some manual memory computation.

Signed-off-by: Jeff King <peff@peff.net>
---
 http.c        |  7 ++++---
 pack-bitmap.c | 13 ++++---------
 sha1_file.c   |  6 ++++--
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/http.c b/http.c
index 7b02259..e0ff876 100644
--- a/http.c
+++ b/http.c
@@ -1511,6 +1511,7 @@ int finish_http_pack_request(struct http_pack_request *preq)
 	struct packed_git **lst;
 	struct packed_git *p = preq->target;
 	char *tmp_idx;
+	size_t len;
 	struct child_process ip = CHILD_PROCESS_INIT;
 	const char *ip_argv[8];
 
@@ -1524,9 +1525,9 @@ int finish_http_pack_request(struct http_pack_request *preq)
 		lst = &((*lst)->next);
 	*lst = (*lst)->next;
 
-	tmp_idx = xstrdup(preq->tmpfile);
-	strcpy(tmp_idx + strlen(tmp_idx) - strlen(".pack.temp"),
-	       ".idx.temp");
+	if (!strip_suffix(preq->tmpfile, ".pack.temp", &len))
+		die("BUG: pack tmpfile does not end in .pack.temp?");
+	tmp_idx = xstrfmt("%.*s.idx.temp", (int)len, preq->tmpfile);
 
 	ip_argv[0] = "index-pack";
 	ip_argv[1] = "-o";
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 637770a..7dfcb34 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -252,16 +252,11 @@ static int load_bitmap_entries_v1(struct bitmap_index *index)
 
 static char *pack_bitmap_filename(struct packed_git *p)
 {
-	char *idx_name;
-	int len;
-
-	len = strlen(p->pack_name) - strlen(".pack");
-	idx_name = xmalloc(len + strlen(".bitmap") + 1);
-
-	memcpy(idx_name, p->pack_name, len);
-	memcpy(idx_name + len, ".bitmap", strlen(".bitmap") + 1);
+	size_t len;
 
-	return idx_name;
+	if (!strip_suffix(p->pack_name, ".pack", &len))
+		die("BUG: pack_name does not end in .pack");
+	return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 }
 
 static int open_pack_bitmap_1(struct packed_git *packfile)
diff --git a/sha1_file.c b/sha1_file.c
index 592226e..2be1afd 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -671,13 +671,15 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
 int open_pack_index(struct packed_git *p)
 {
 	char *idx_name;
+	size_t len;
 	int ret;
 
 	if (p->index_data)
 		return 0;
 
-	idx_name = xstrdup(p->pack_name);
-	strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
+	if (!strip_suffix(p->pack_name, ".pack", &len))
+		die("BUG: pack_name does not end in .pack");
+	idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 	ret = check_packed_git_idx(idx_name, p);
 	free(idx_name);
 	return ret;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 30/68] ref-filter: drop sprintf and strcpy calls

[Jeff King]

The ref-filter code comes from for-each-ref, and inherited a
number of raw sprintf and strcpy calls. These are generally
all safe, as we custom-size the buffers, or are formatting
numbers into sufficiently large buffers. But we can make the
resulting code even simpler and more obviously correct by
using some of our helper functions.

Signed-off-by: Jeff King <peff@peff.net>
---
 ref-filter.c | 70 +++++++++++++++++++-----------------------------------------
 1 file changed, 22 insertions(+), 48 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index f38dee4..1f71870 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -192,9 +192,7 @@ static int grab_objectname(const char *name, const unsigned char *sha1,
 			    struct atom_value *v)
 {
 	if (!strcmp(name, "objectname")) {
-		char *s = xmalloc(41);
-		strcpy(s, sha1_to_hex(sha1));
-		v->s = s;
+		v->s = xstrdup(sha1_to_hex(sha1));
 		return 1;
 	}
 	if (!strcmp(name, "objectname:short")) {
@@ -219,10 +217,8 @@ static void grab_common_values(struct atom_value *val, int deref, struct object
 		if (!strcmp(name, "objecttype"))
 			v->s = typename(obj->type);
 		else if (!strcmp(name, "objectsize")) {
-			char *s = xmalloc(40);
-			sprintf(s, "%lu", sz);
 			v->ul = sz;
-			v->s = s;
+			v->s = xstrfmt("%lu", sz);
 		}
 		else if (deref)
 			grab_objectname(name, obj->sha1, v);
@@ -246,11 +242,8 @@ static void grab_tag_values(struct atom_value *val, int deref, struct object *ob
 			v->s = tag->tag;
 		else if (!strcmp(name, "type") && tag->tagged)
 			v->s = typename(tag->tagged->type);
-		else if (!strcmp(name, "object") && tag->tagged) {
-			char *s = xmalloc(41);
-			strcpy(s, sha1_to_hex(tag->tagged->sha1));
-			v->s = s;
-		}
+		else if (!strcmp(name, "object") && tag->tagged)
+			v->s = xstrdup(sha1_to_hex(tag->tagged->sha1));
 	}
 }
 
@@ -268,32 +261,22 @@ static void grab_commit_values(struct atom_value *val, int deref, struct object
 		if (deref)
 			name++;
 		if (!strcmp(name, "tree")) {
-			char *s = xmalloc(41);
-			strcpy(s, sha1_to_hex(commit->tree->object.sha1));
-			v->s = s;
+			v->s = xstrdup(sha1_to_hex(commit->tree->object.sha1));
 		}
-		if (!strcmp(name, "numparent")) {
-			char *s = xmalloc(40);
+		else if (!strcmp(name, "numparent")) {
 			v->ul = commit_list_count(commit->parents);
-			sprintf(s, "%lu", v->ul);
-			v->s = s;
+			v->s = xstrfmt("%lu", v->ul);
 		}
 		else if (!strcmp(name, "parent")) {
-			int num = commit_list_count(commit->parents);
-			int i;
 			struct commit_list *parents;
-			char *s = xmalloc(41 * num + 1);
-			v->s = s;
-			for (i = 0, parents = commit->parents;
-			     parents;
-			     parents = parents->next, i = i + 41) {
+			struct strbuf s = STRBUF_INIT;
+			for (parents = commit->parents; parents; parents = parents->next) {
 				struct commit *parent = parents->item;
-				strcpy(s+i, sha1_to_hex(parent->object.sha1));
-				if (parents->next)
-					s[i+40] = ' ';
+				if (parents != commit->parents)
+					strbuf_addch(&s, ' ');
+				strbuf_addstr(&s, sha1_to_hex(parent->object.sha1));
 			}
-			if (!i)
-				*s = '\0';
+			v->s = strbuf_detach(&s, NULL);
 		}
 	}
 }
@@ -700,7 +683,6 @@ static void populate_value(struct ref_array_item *ref)
 			else if (!strcmp(formatp, "track") &&
 				 (starts_with(name, "upstream") ||
 				  starts_with(name, "push"))) {
-				char buf[40];
 
 				if (stat_tracking_info(branch, &num_ours,
 						       &num_theirs, NULL))
@@ -708,17 +690,13 @@ static void populate_value(struct ref_array_item *ref)
 
 				if (!num_ours && !num_theirs)
 					v->s = "";
-				else if (!num_ours) {
-					sprintf(buf, "[behind %d]", num_theirs);
-					v->s = xstrdup(buf);
-				} else if (!num_theirs) {
-					sprintf(buf, "[ahead %d]", num_ours);
-					v->s = xstrdup(buf);
-				} else {
-					sprintf(buf, "[ahead %d, behind %d]",
-						num_ours, num_theirs);
-					v->s = xstrdup(buf);
-				}
+				else if (!num_ours)
+					v->s = xstrfmt("[behind %d]", num_theirs);
+				else if (!num_theirs)
+					v->s = xstrfmt("[ahead %d]", num_ours);
+				else
+					v->s = xstrfmt("[ahead %d, behind %d]",
+						       num_ours, num_theirs);
 				continue;
 			} else if (!strcmp(formatp, "trackshort") &&
 				   (starts_with(name, "upstream") ||
@@ -745,12 +723,8 @@ static void populate_value(struct ref_array_item *ref)
 
 		if (!deref)
 			v->s = refname;
-		else {
-			int len = strlen(refname);
-			char *s = xmalloc(len + 4);
-			sprintf(s, "%s^{}", refname);
-			v->s = s;
-		}
+		else
+			v->s = xstrfmt("%s^{}", refname);
 	}
 
 	for (i = 0; i < used_atom_cnt; i++) {
-- 
2.6.0.rc3.454.g204ad51

[PATCH 31/68] help: drop prepend function in favor of xstrfmt

[Jeff King]

This function predates xstrfmt, and its functionality is a
subset. Let's just use xstrfmt.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/help.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/builtin/help.c b/builtin/help.c
index 3422e73..fba8c01 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -295,16 +295,6 @@ static int is_git_command(const char *s)
 		is_in_cmdlist(&other_cmds, s);
 }
 
-static const char *prepend(const char *prefix, const char *cmd)
-{
-	size_t pre_len = strlen(prefix);
-	size_t cmd_len = strlen(cmd);
-	char *p = xmalloc(pre_len + cmd_len + 1);
-	memcpy(p, prefix, pre_len);
-	strcpy(p + pre_len, cmd);
-	return p;
-}
-
 static const char *cmd_to_page(const char *git_cmd)
 {
 	if (!git_cmd)
@@ -312,9 +302,9 @@ static const char *cmd_to_page(const char *git_cmd)
 	else if (starts_with(git_cmd, "git"))
 		return git_cmd;
 	else if (is_git_command(git_cmd))
-		return prepend("git-", git_cmd);
+		return xstrfmt("git-%s", git_cmd);
 	else
-		return prepend("git", git_cmd);
+		return xstrfmt("git%s", git_cmd);
 }
 
 static void setup_man_path(void)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 32/68] mailmap: replace strcpy with xstrdup

[Jeff King]

We want to make a copy of a string without any leading
whitespace. To do so, we allocate a buffer large enough to
hold the original, skip past the whitespace, then copy that.
It's much simpler to just allocate after we've skipped, in
which case we can just copy the remainder of the string,
leaving no question of whether "len" is large enough.

Signed-off-by: Jeff King <peff@peff.net>
---
 mailmap.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mailmap.c b/mailmap.c
index 9e95897..f4a0f1c 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -162,11 +162,10 @@ static void read_mailmap_line(struct string_list *map, char *buffer,
 			char *cp;
 
 			free(*repo_abbrev);
-			*repo_abbrev = xmalloc(len);
 
 			for (cp = buffer + abblen; isspace(*cp); cp++)
 				; /* nothing */
-			strcpy(*repo_abbrev, cp);
+			*repo_abbrev = xstrdup(cp);
 		}
 		return;
 	}
-- 
2.6.0.rc3.454.g204ad51

[PATCH 33/68] read_branches_file: simplify string handling

[Jeff King]

This function does a lot of manual string handling, and has
some unnecessary limits. This patch cleans up a number of
things:

  1. Drop the arbitrary 1000-byte limit on the size of the
     remote name (we do not have such a limit in any of the
     other remote-reading mechanisms).

  2. Replace fgets into a fixed-size buffer with a strbuf,
     eliminating any limits on the length of the URL.

  3. Replace manual whitespace handling with strbuf_trim
     (since we now have a strbuf). This also gets rid
     of a call to strcpy, and the confusing reuse of the "p"
     pointer for multiple purposes.

  4. We currently build up the refspecs over multiple strbuf
     calls. We do this to handle the fact that the URL "frag"
     may not be present. But rather than have multiple
     conditionals, let's just default "frag" to "master".
     This lets us format the refspecs with a single xstrfmt.
     It's shorter, and easier to see what the final string
     looks like.

     We also update the misleading comment in this area (the
     local branch is named after the remote name, not after
     the branch name on the remote side).

Signed-off-by: Jeff King <peff@peff.net>
---
 remote.c | 54 ++++++++++++++++++++----------------------------------
 1 file changed, 20 insertions(+), 34 deletions(-)

diff --git a/remote.c b/remote.c
index 5ab0f7f..22a60fc 100644
--- a/remote.c
+++ b/remote.c
@@ -293,56 +293,42 @@ static void read_remotes_file(struct remote *remote)
 static void read_branches_file(struct remote *remote)
 {
 	char *frag;
-	struct strbuf branch = STRBUF_INIT;
-	int n = 1000;
-	FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
-	char *s, *p;
-	int len;
+	struct strbuf buf = STRBUF_INIT;
+	FILE *f = fopen(git_path("branches/%s", remote->name), "r");
 
 	if (!f)
 		return;
-	s = fgets(buffer, BUF_SIZE, f);
-	fclose(f);
-	if (!s)
-		return;
-	while (isspace(*s))
-		s++;
-	if (!*s)
+
+	strbuf_getline(&buf, f, '\n');
+	strbuf_trim(&buf);
+	if (!buf.len) {
+		strbuf_release(&buf);
 		return;
+	}
+
 	remote->origin = REMOTE_BRANCHES;
-	p = s + strlen(s);
-	while (isspace(p[-1]))
-		*--p = 0;
-	len = p - s;
-	p = xmalloc(len + 1);
-	strcpy(p, s);
 
 	/*
 	 * The branches file would have URL and optionally
 	 * #branch specified.  The "master" (or specified) branch is
-	 * fetched and stored in the local branch of the same name.
+	 * fetched and stored in the local branch matching the
+	 * remote name.
 	 */
-	frag = strchr(p, '#');
-	if (frag) {
+	frag = strchr(buf.buf, '#');
+	if (frag)
 		*(frag++) = '\0';
-		strbuf_addf(&branch, "refs/heads/%s", frag);
-	} else
-		strbuf_addstr(&branch, "refs/heads/master");
+	else
+		frag = "master";
+
+	add_url_alias(remote, strbuf_detach(&buf, NULL));
+	add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
+					  frag, remote->name));
 
-	strbuf_addf(&branch, ":refs/heads/%s", remote->name);
-	add_url_alias(remote, p);
-	add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 	/*
 	 * Cogito compatible push: push current HEAD to remote #branch
 	 * (master if missing)
 	 */
-	strbuf_init(&branch, 0);
-	strbuf_addstr(&branch, "HEAD");
-	if (frag)
-		strbuf_addf(&branch, ":refs/heads/%s", frag);
-	else
-		strbuf_addstr(&branch, ":refs/heads/master");
-	add_push_refspec(remote, strbuf_detach(&branch, NULL));
+	add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
 	remote->fetch_tags = 1; /* always auto-follow */
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 34/68] read_remotes_file: simplify string handling

[Jeff King]

The main motivation for this cleanup is to switch our
line-reading to a strbuf, which removes the use of a
fixed-size buffer (which limited the size of remote URLs).
Since we have the strbuf, we can make use of strbuf_rtrim().

While we're here, we can also simplify the parsing of each
line.  First, we can use skip_prefix() to avoid some magic
numbers.

But second, we can avoid splitting the parsing and actions
for each line into two stages. Right now we figure out which
type of line we have, set an int to a magic number,
skip any intermediate whitespace, and then act on
the resulting value based on the magic number.

Instead, let's factor the whitespace skipping into a
function. That lets us avoid the magic numbers and keep the
actions close to the parsing.

Signed-off-by: Jeff King <peff@peff.net>
---
 remote.c | 55 ++++++++++++++++++-------------------------------------
 1 file changed, 18 insertions(+), 37 deletions(-)

diff --git a/remote.c b/remote.c
index 22a60fc..a01f13a 100644
--- a/remote.c
+++ b/remote.c
@@ -54,9 +54,6 @@ static const char *pushremote_name;
 static struct rewrites rewrites;
 static struct rewrites rewrites_push;
 
-#define BUF_SIZE (2048)
-static char buffer[BUF_SIZE];
-
 static int valid_remote(const struct remote *remote)
 {
 	return (!!remote->url) || (!!remote->foreign_vcs);
@@ -243,50 +240,34 @@ static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 	rewrite->instead_of_nr++;
 }
 
+static const char *skip_spaces(const char *s)
+{
+	while (isspace(*s))
+		s++;
+	return s;
+}
+
 static void read_remotes_file(struct remote *remote)
 {
+	struct strbuf buf = STRBUF_INIT;
 	FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 
 	if (!f)
 		return;
 	remote->origin = REMOTE_REMOTES;
-	while (fgets(buffer, BUF_SIZE, f)) {
-		int value_list;
-		char *s, *p;
-
-		if (starts_with(buffer, "URL:")) {
-			value_list = 0;
-			s = buffer + 4;
-		} else if (starts_with(buffer, "Push:")) {
-			value_list = 1;
-			s = buffer + 5;
-		} else if (starts_with(buffer, "Pull:")) {
-			value_list = 2;
-			s = buffer + 5;
-		} else
-			continue;
-
-		while (isspace(*s))
-			s++;
-		if (!*s)
-			continue;
+	while (strbuf_getline(&buf, f, '\n') != EOF) {
+		const char *v;
 
-		p = s + strlen(s);
-		while (isspace(p[-1]))
-			*--p = 0;
+		strbuf_rtrim(&buf);
 
-		switch (value_list) {
-		case 0:
-			add_url_alias(remote, xstrdup(s));
-			break;
-		case 1:
-			add_push_refspec(remote, xstrdup(s));
-			break;
-		case 2:
-			add_fetch_refspec(remote, xstrdup(s));
-			break;
-		}
+		if (skip_prefix(buf.buf, "URL:", &v))
+			add_url_alias(remote, xstrdup(skip_spaces(v)));
+		else if (skip_prefix(buf.buf, "Push:", &v))
+			add_push_refspec(remote, xstrdup(skip_spaces(v)));
+		else if (skip_prefix(buf.buf, "Pull:", &v))
+			add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
 	}
+	strbuf_release(&buf);
 	fclose(f);
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 35/68] resolve_ref: use strbufs for internal buffers

[Jeff King]

resolve_ref already uses a strbuf internally when generating
pathnames, but it uses fixed-size buffers for storing the
refname and symbolic refs. This means that you cannot
actually point HEAD to a ref that is larger than 256 bytes.

We can lift this limit by using strbufs here, too. Like
sb_path, we pass the the buffers into our helper function,
so that we can easily clean up all output paths. We can also
drop the "unsafe" name from our helper function, as it no
longer uses a single static buffer (but of course
resolve_ref_unsafe is still unsafe, because the static
buffers moved there).

As a bonus, we also get to drop some strcpy calls between
the two fixed buffers (that cannot currently overflow
because the two buffers are sized identically).

Signed-off-by: Jeff King <peff@peff.net>
---
 refs.c                  | 57 ++++++++++++++++++++++++++-----------------------
 t/t1401-symbolic-ref.sh | 29 +++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 27 deletions(-)

diff --git a/refs.c b/refs.c
index d5c8b2f..c2709de 100644
--- a/refs.c
+++ b/refs.c
@@ -1579,16 +1579,15 @@ static int resolve_missing_loose_ref(const char *refname,
 }
 
 /* This function needs to return a meaningful errno on failure */
-static const char *resolve_ref_unsafe_1(const char *refname,
-					int resolve_flags,
-					unsigned char *sha1,
-					int *flags,
-					struct strbuf *sb_path)
+static const char *resolve_ref_1(const char *refname,
+				 int resolve_flags,
+				 unsigned char *sha1,
+				 int *flags,
+				 struct strbuf *sb_refname,
+				 struct strbuf *sb_path,
+				 struct strbuf *sb_contents)
 {
 	int depth = MAXDEPTH;
-	ssize_t len;
-	char buffer[256];
-	static char refname_buffer[256];
 	int bad_name = 0;
 
 	if (flags)
@@ -1654,19 +1653,18 @@ static const char *resolve_ref_unsafe_1(const char *refname,
 
 		/* Follow "normalized" - ie "refs/.." symlinks by hand */
 		if (S_ISLNK(st.st_mode)) {
-			len = readlink(path, buffer, sizeof(buffer)-1);
-			if (len < 0) {
+			strbuf_reset(sb_contents);
+			if (strbuf_readlink(sb_contents, path, 0) < 0) {
 				if (errno == ENOENT || errno == EINVAL)
 					/* inconsistent with lstat; retry */
 					goto stat_ref;
 				else
 					return NULL;
 			}
-			buffer[len] = 0;
-			if (starts_with(buffer, "refs/") &&
-					!check_refname_format(buffer, 0)) {
-				strcpy(refname_buffer, buffer);
-				refname = refname_buffer;
+			if (starts_with(sb_contents->buf, "refs/") &&
+			    !check_refname_format(sb_contents->buf, 0)) {
+				strbuf_swap(sb_refname, sb_contents);
+				refname = sb_refname->buf;
 				if (flags)
 					*flags |= REF_ISSYMREF;
 				if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
@@ -1695,28 +1693,26 @@ static const char *resolve_ref_unsafe_1(const char *refname,
 			else
 				return NULL;
 		}
-		len = read_in_full(fd, buffer, sizeof(buffer)-1);
-		if (len < 0) {
+		strbuf_reset(sb_contents);
+		if (strbuf_read(sb_contents, fd, 256) < 0) {
 			int save_errno = errno;
 			close(fd);
 			errno = save_errno;
 			return NULL;
 		}
 		close(fd);
-		while (len && isspace(buffer[len-1]))
-			len--;
-		buffer[len] = '\0';
+		strbuf_rtrim(sb_contents);
 
 		/*
 		 * Is it a symbolic ref?
 		 */
-		if (!starts_with(buffer, "ref:")) {
+		if (!starts_with(sb_contents->buf, "ref:")) {
 			/*
 			 * Please note that FETCH_HEAD has a second
 			 * line containing other data.
 			 */
-			if (get_sha1_hex(buffer, sha1) ||
-			    (buffer[40] != '\0' && !isspace(buffer[40]))) {
+			if (get_sha1_hex(sb_contents->buf, sha1) ||
+			    (sb_contents->buf[40] != '\0' && !isspace(sb_contents->buf[40]))) {
 				if (flags)
 					*flags |= REF_ISBROKEN;
 				errno = EINVAL;
@@ -1731,10 +1727,12 @@ static const char *resolve_ref_unsafe_1(const char *refname,
 		}
 		if (flags)
 			*flags |= REF_ISSYMREF;
-		buf = buffer + 4;
+		buf = sb_contents->buf + 4;
 		while (isspace(*buf))
 			buf++;
-		refname = strcpy(refname_buffer, buf);
+		strbuf_reset(sb_refname);
+		strbuf_addstr(sb_refname, buf);
+		refname = sb_refname->buf;
 		if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
 			hashclr(sha1);
 			return refname;
@@ -1756,10 +1754,15 @@ static const char *resolve_ref_unsafe_1(const char *refname,
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
+	static struct strbuf sb_refname = STRBUF_INIT;
+	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
-	const char *ret = resolve_ref_unsafe_1(refname, resolve_flags,
-					       sha1, flags, &sb_path);
+	const char *ret;
+
+	ret = resolve_ref_1(refname, resolve_flags, sha1, flags,
+			    &sb_refname, &sb_path, &sb_contents);
 	strbuf_release(&sb_path);
+	strbuf_release(&sb_contents);
 	return ret;
 }
 
diff --git a/t/t1401-symbolic-ref.sh b/t/t1401-symbolic-ref.sh
index 36378b0..20b022a 100755
--- a/t/t1401-symbolic-ref.sh
+++ b/t/t1401-symbolic-ref.sh
@@ -63,4 +63,33 @@ test_expect_success 'symbolic-ref fails to delete real ref' '
 '
 reset_to_sane
 
+test_expect_success 'create large ref name' '
+	# make 256+ character ref; some systems may not handle that,
+	# so be gentle
+	long=0123456789abcdef &&
+	long=$long/$long/$long/$long &&
+	long=$long/$long/$long/$long &&
+	long_ref=refs/heads/$long &&
+	tree=$(git write-tree) &&
+	commit=$(echo foo | git commit-tree $tree) &&
+	if git update-ref $long_ref $commit; then
+		test_set_prereq LONG_REF
+	else
+		echo >&2 "long refs not supported"
+	fi
+'
+
+test_expect_success LONG_REF 'symbolic-ref can point to large ref name' '
+	git symbolic-ref HEAD $long_ref &&
+	echo $long_ref >expect &&
+	git symbolic-ref HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success LONG_REF 'we can parse long symbolic ref' '
+	echo $commit >expect &&
+	git rev-parse --verify HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_done
-- 
2.6.0.rc3.454.g204ad51

[PATCH 36/68] upload-archive: convert sprintf to strbuf

[Jeff King]

When we report an error to the client, we format it into a
fixed-size buffer using vsprintf(). This can't actually
overflow in practice, since we only format a very tame
subset of strings (mostly strerror() output). However, it's
hard to tell immediately, so let's just use a strbuf so
readers do not have to wonder.

We do add an allocation here, but the performance is not
important; the next step is to call die() anyway.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/upload-archive.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/builtin/upload-archive.c b/builtin/upload-archive.c
index 32ab94c..dbfe14f 100644
--- a/builtin/upload-archive.c
+++ b/builtin/upload-archive.c
@@ -49,15 +49,14 @@ int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix)
 __attribute__((format (printf, 1, 2)))
 static void error_clnt(const char *fmt, ...)
 {
-	char buf[1024];
+	struct strbuf buf = STRBUF_INIT;
 	va_list params;
-	int len;
 
 	va_start(params, fmt);
-	len = vsprintf(buf, fmt, params);
+	strbuf_vaddf(&buf, fmt, params);
 	va_end(params);
-	send_sideband(1, 3, buf, len, LARGE_PACKET_MAX);
-	die("sent error to the client: %s", buf);
+	send_sideband(1, 3, buf.buf, buf.len, LARGE_PACKET_MAX);
+	die("sent error to the client: %s", buf.buf);
 }
 
 static ssize_t process_input(int child_fd, int band)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 37/68] remote-ext: simplify git pkt-line generation

[Jeff King]

We format a pkt-line into a heap buffer, which requires
manual computation of the required size, and uses some bare
sprintf calls. We could use a strbuf instead, which would
take care of the computation for us. But it's even easier
still to use packet_write(). Besides handling the formatting
and writing for us, it fixes two things:

  1. Our manual max-size check used 0xFFFF, while technically
     LARGE_PACKET_MAX is slightly smaller than this.

  2. Our packet will now be output as part of
     GIT_TRACE_PACKET debugging.

Unfortunately packet_write() does not let us build up the
buffer progressively, so we do have to repeat ourselves a
little depending on the "vhost" setting, but the end result
is still far more readable than the original.

Since there were no tests covering this feature at all,
we'll add a few into t5802.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/remote-ext.c      | 34 +++++-----------------------------
 t/t5802-connect-helper.sh | 28 ++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/builtin/remote-ext.c b/builtin/remote-ext.c
index 3b8c22c..e3cd25d 100644
--- a/builtin/remote-ext.c
+++ b/builtin/remote-ext.c
@@ -1,6 +1,7 @@
 #include "builtin.h"
 #include "transport.h"
 #include "run-command.h"
+#include "pkt-line.h"
 
 /*
  * URL syntax:
@@ -142,36 +143,11 @@ static const char **parse_argv(const char *arg, const char *service)
 static void send_git_request(int stdin_fd, const char *serv, const char *repo,
 	const char *vhost)
 {
-	size_t bufferspace;
-	size_t wpos = 0;
-	char *buffer;
-
-	/*
-	 * Request needs 12 bytes extra if there is vhost (xxxx \0host=\0) and
-	 * 6 bytes extra (xxxx \0) if there is no vhost.
-	 */
-	if (vhost)
-		bufferspace = strlen(serv) + strlen(repo) + strlen(vhost) + 12;
+	if (!vhost)
+		packet_write(stdin_fd, "%s %s%c", serv, repo, 0);
 	else
-		bufferspace = strlen(serv) + strlen(repo) + 6;
-
-	if (bufferspace > 0xFFFF)
-		die("Request too large to send");
-	buffer = xmalloc(bufferspace);
-
-	/* Make the packet. */
-	wpos = sprintf(buffer, "%04x%s %s%c", (unsigned)bufferspace,
-		serv, repo, 0);
-
-	/* Add vhost if any. */
-	if (vhost)
-		sprintf(buffer + wpos, "host=%s%c", vhost, 0);
-
-	/* Send the request */
-	if (write_in_full(stdin_fd, buffer, bufferspace) < 0)
-		die_errno("Failed to send request");
-
-	free(buffer);
+		packet_write(stdin_fd, "%s %s%chost=%s%c", serv, repo, 0,
+			     vhost, 0);
 }
 
 static int run_child(const char *arg, const char *service)
diff --git a/t/t5802-connect-helper.sh b/t/t5802-connect-helper.sh
index 878faf2..b7a7f9d 100755
--- a/t/t5802-connect-helper.sh
+++ b/t/t5802-connect-helper.sh
@@ -69,4 +69,32 @@ test_expect_success 'update backfilled tag without primary transfer' '
 	test_cmp expect actual
 '
 
+
+test_expect_success 'set up fake git-daemon' '
+	mkdir remote &&
+	git init --bare remote/one.git &&
+	mkdir remote/host &&
+	git init --bare remote/host/two.git &&
+	write_script fake-daemon <<-\EOF &&
+	git daemon --inetd \
+		--informative-errors \
+		--export-all \
+		--base-path="$TRASH_DIRECTORY/remote" \
+		--interpolated-path="$TRASH_DIRECTORY/remote/%H%D" \
+		"$TRASH_DIRECTORY/remote"
+	EOF
+	export TRASH_DIRECTORY &&
+	PATH=$TRASH_DIRECTORY:$PATH
+'
+
+test_expect_success 'ext command can connect to git daemon (no vhost)' '
+	rm -rf dst &&
+	git clone "ext::fake-daemon %G/one.git" dst
+'
+
+test_expect_success 'ext command can connect to git daemon (vhost)' '
+	rm -rf dst &&
+	git clone "ext::fake-daemon %G/two.git %Vhost" dst
+'
+
 test_done
-- 
2.6.0.rc3.454.g204ad51

[PATCH 38/68] http-push: use strbuf instead of fwrite_buffer

[Jeff King]

The http-push code defines an fwrite_buffer function for use
as a curl callback; it just writes to a strbuf. There's no
reason we need to use it ourselves, as we know we have a
strbuf. This lets us format directly into it, rather than
dealing with an extra temporary buffer (which required
manual length computation).

While we're here, let's also remove the literal tabs from
the source in favor of "\t", which is more visually obvious.

Signed-off-by: Jeff King <peff@peff.net>
---
 http-push.c | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/http-push.c b/http-push.c
index 37baff8..e501c28 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1459,8 +1459,6 @@ static void add_remote_info_ref(struct remote_ls_ctx *ls)
 {
 	struct strbuf *buf = (struct strbuf *)ls->userData;
 	struct object *o;
-	int len;
-	char *ref_info;
 	struct ref *ref;
 
 	ref = alloc_ref(ls->dentry_name);
@@ -1484,23 +1482,14 @@ static void add_remote_info_ref(struct remote_ls_ctx *ls)
 		return;
 	}
 
-	len = strlen(ls->dentry_name) + 42;
-	ref_info = xcalloc(len + 1, 1);
-	sprintf(ref_info, "%s	%s\n",
-		sha1_to_hex(ref->old_sha1), ls->dentry_name);
-	fwrite_buffer(ref_info, 1, len, buf);
-	free(ref_info);
+	strbuf_addf(buf, "%s\t%s\n",
+		    sha1_to_hex(ref->old_sha1), ls->dentry_name);
 
 	if (o->type == OBJ_TAG) {
 		o = deref_tag(o, ls->dentry_name, 0);
-		if (o) {
-			len = strlen(ls->dentry_name) + 45;
-			ref_info = xcalloc(len + 1, 1);
-			sprintf(ref_info, "%s	%s^{}\n",
-				sha1_to_hex(o->sha1), ls->dentry_name);
-			fwrite_buffer(ref_info, 1, len, buf);
-			free(ref_info);
-		}
+		if (o)
+			strbuf_addf(buf, "%s\t%s^{}\n",
+				    sha1_to_hex(o->sha1), ls->dentry_name);
 	}
 	free(ref);
 }
-- 
2.6.0.rc3.454.g204ad51

[PATCH 39/68] http-walker: store url in a strbuf

[Jeff King]

We do an unchecked sprintf directly into our url buffer.
This doesn't overflow because we know that it was sized for
"$base/objects/info/http-alternates", and we are writing
"$base/objects/info/alternates", which must be smaller. But
that is not immediately obvious to a reader who is looking
for buffer overflows. Let's switch to a strbuf, so that we
do not have to think about this issue at all.

Signed-off-by: Jeff King <peff@peff.net>
---
 http-walker.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/http-walker.c b/http-walker.c
index 88da546..2c721f0 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -29,7 +29,7 @@ struct object_request {
 struct alternates_request {
 	struct walker *walker;
 	const char *base;
-	char *url;
+	struct strbuf *url;
 	struct strbuf *buffer;
 	struct active_request_slot *slot;
 	int http_specific;
@@ -195,10 +195,11 @@ static void process_alternates_response(void *callback_data)
 
 			/* Try reusing the slot to get non-http alternates */
 			alt_req->http_specific = 0;
-			sprintf(alt_req->url, "%s/objects/info/alternates",
-				base);
+			strbuf_reset(alt_req->url);
+			strbuf_addf(alt_req->url, "%s/objects/info/alternates",
+				    base);
 			curl_easy_setopt(slot->curl, CURLOPT_URL,
-					 alt_req->url);
+					 alt_req->url->buf);
 			active_requests++;
 			slot->in_use = 1;
 			if (slot->finished != NULL)
@@ -312,7 +313,7 @@ static void process_alternates_response(void *callback_data)
 static void fetch_alternates(struct walker *walker, const char *base)
 {
 	struct strbuf buffer = STRBUF_INIT;
-	char *url;
+	struct strbuf url = STRBUF_INIT;
 	struct active_request_slot *slot;
 	struct alternates_request alt_req;
 	struct walker_data *cdata = walker->data;
@@ -338,7 +339,7 @@ static void fetch_alternates(struct walker *walker, const char *base)
 	if (walker->get_verbosely)
 		fprintf(stderr, "Getting alternates list for %s\n", base);
 
-	url = xstrfmt("%s/objects/info/http-alternates", base);
+	strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 
 	/*
 	 * Use a callback to process the result, since another request
@@ -351,10 +352,10 @@ static void fetch_alternates(struct walker *walker, const char *base)
 
 	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+	curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 
 	alt_req.base = base;
-	alt_req.url = url;
+	alt_req.url = &url;
 	alt_req.buffer = &buffer;
 	alt_req.http_specific = 1;
 	alt_req.slot = slot;
@@ -365,7 +366,7 @@ static void fetch_alternates(struct walker *walker, const char *base)
 		cdata->got_alternates = -1;
 
 	strbuf_release(&buffer);
-	free(url);
+	strbuf_release(&url);
 }
 
 static int fetch_indices(struct walker *walker, struct alt_base *repo)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 40/68] sha1_get_pack_name: use a strbuf

[Jeff King]

We do some manual memory computation here, and there's no
check that our 60 is not overflowed by the raw sprintf (it
isn't, because the "which" parameter is never longer than
"pack"). We can simplify this greatly with a strbuf.

Technically the end result is not identical, as the original
took care not to rewrite the object directory on each call
for performance reasons.  We could do that here, too (by
saving the baselen and resetting to it), but it's not worth
the complexity; this function is not called a lot (generally
once per packfile that we open).

Signed-off-by: Jeff King <peff@peff.net>
---
 sha1_file.c | 39 ++++++++++-----------------------------
 1 file changed, 10 insertions(+), 29 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 2be1afd..c26fdcb 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -208,44 +208,25 @@ const char *sha1_file_name(const unsigned char *sha1)
  * provided by the caller.  which should be "pack" or "idx".
  */
 static char *sha1_get_pack_name(const unsigned char *sha1,
-				char **name, char **base, const char *which)
+				struct strbuf *buf,
+				const char *which)
 {
-	static const char hex[] = "0123456789abcdef";
-	char *buf;
-	int i;
-
-	if (!*base) {
-		const char *sha1_file_directory = get_object_directory();
-		int len = strlen(sha1_file_directory);
-		*base = xmalloc(len + 60);
-		sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
-			sha1_file_directory, which);
-		*name = *base + len + 11;
-	}
-
-	buf = *name;
-
-	for (i = 0; i < 20; i++) {
-		unsigned int val = *sha1++;
-		*buf++ = hex[val >> 4];
-		*buf++ = hex[val & 0xf];
-	}
-
-	return *base;
+	strbuf_reset(buf);
+	strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
+		    sha1_to_hex(sha1), which);
+	return buf->buf;
 }
 
 char *sha1_pack_name(const unsigned char *sha1)
 {
-	static char *name, *base;
-
-	return sha1_get_pack_name(sha1, &name, &base, "pack");
+	static struct strbuf buf = STRBUF_INIT;
+	return sha1_get_pack_name(sha1, &buf, "pack");
 }
 
 char *sha1_pack_index_name(const unsigned char *sha1)
 {
-	static char *name, *base;
-
-	return sha1_get_pack_name(sha1, &name, &base, "idx");
+	static struct strbuf buf = STRBUF_INIT;
+	return sha1_get_pack_name(sha1, &buf, "idx");
 }
 
 struct alternate_object_database *alt_odb_list;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 41/68] init: use strbufs to store paths

[Jeff King]

The init code predates strbufs, and uses PATH_MAX-sized
buffers along with many manual checks on intermediate sizes
(some of which make magic assumptions, such as that init
will not create a path inside .git longer than 50
characters).

We can simplify this greatly by using strbufs, which drops
some hard-to-verify strcpy calls.  Note that we need to
update probe_utf8_pathname_composition, too, as it assumes
we are passing a buffer large enough to append its probe
filenames (it now just takes a strbuf, which also gets rid
of the confusing "len" parameter, which was not the length of
"path" but rather the offset to start writing).

Some of the conversion makes new calls to git_path_buf.
While we're in the area, let's also convert existing calls
to git_path to the safer git_path_buf (our existing calls
were passed to pretty tame functions, and so were not a
problem, but it's easy to be consistent and safe here).

Note that we had an explicit test that "git init" rejects
long template directories. This comes from 32d1776 (init: Do
not segfault on big GIT_TEMPLATE_DIR environment variable,
2009-04-18). We can drop the test_must_fail here, as we now
accept this and need only confirm that we don't segfault,
which was the original point of the test.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/init-db.c        | 174 ++++++++++++++++++++---------------------------
 compat/precompose_utf8.c |  12 ++--
 compat/precompose_utf8.h |   2 +-
 git-compat-util.h        |   2 +-
 t/t0001-init.sh          |   4 +-
 5 files changed, 87 insertions(+), 107 deletions(-)

diff --git a/builtin/init-db.c b/builtin/init-db.c
index e7d0e31..cf6a3c8 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -36,10 +36,11 @@ static void safe_create_dir(const char *dir, int share)
 		die(_("Could not make %s writable by group"), dir);
 }
 
-static void copy_templates_1(char *path, int baselen,
-			     char *template, int template_baselen,
+static void copy_templates_1(struct strbuf *path, struct strbuf *template,
 			     DIR *dir)
 {
+	size_t path_baselen = path->len;
+	size_t template_baselen = template->len;
 	struct dirent *de;
 
 	/* Note: if ".git/hooks" file exists in the repository being
@@ -49,77 +50,64 @@ static void copy_templates_1(char *path, int baselen,
 	 * with the way the namespace under .git/ is organized, should
 	 * be really carefully chosen.
 	 */
-	safe_create_dir(path, 1);
+	safe_create_dir(path->buf, 1);
 	while ((de = readdir(dir)) != NULL) {
 		struct stat st_git, st_template;
-		int namelen;
 		int exists = 0;
 
+		strbuf_setlen(path, path_baselen);
+		strbuf_setlen(template, template_baselen);
+
 		if (de->d_name[0] == '.')
 			continue;
-		namelen = strlen(de->d_name);
-		if ((PATH_MAX <= baselen + namelen) ||
-		    (PATH_MAX <= template_baselen + namelen))
-			die(_("insanely long template name %s"), de->d_name);
-		memcpy(path + baselen, de->d_name, namelen+1);
-		memcpy(template + template_baselen, de->d_name, namelen+1);
-		if (lstat(path, &st_git)) {
+		strbuf_addstr(path, de->d_name);
+		strbuf_addstr(template, de->d_name);
+		if (lstat(path->buf, &st_git)) {
 			if (errno != ENOENT)
-				die_errno(_("cannot stat '%s'"), path);
+				die_errno(_("cannot stat '%s'"), path->buf);
 		}
 		else
 			exists = 1;
 
-		if (lstat(template, &st_template))
-			die_errno(_("cannot stat template '%s'"), template);
+		if (lstat(template->buf, &st_template))
+			die_errno(_("cannot stat template '%s'"), template->buf);
 
 		if (S_ISDIR(st_template.st_mode)) {
-			DIR *subdir = opendir(template);
-			int baselen_sub = baselen + namelen;
-			int template_baselen_sub = template_baselen + namelen;
+			DIR *subdir = opendir(template->buf);
 			if (!subdir)
-				die_errno(_("cannot opendir '%s'"), template);
-			path[baselen_sub++] =
-				template[template_baselen_sub++] = '/';
-			path[baselen_sub] =
-				template[template_baselen_sub] = 0;
-			copy_templates_1(path, baselen_sub,
-					 template, template_baselen_sub,
-					 subdir);
+				die_errno(_("cannot opendir '%s'"), template->buf);
+			strbuf_addch(path, '/');
+			strbuf_addch(template, '/');
+			copy_templates_1(path, template, subdir);
 			closedir(subdir);
 		}
 		else if (exists)
 			continue;
 		else if (S_ISLNK(st_template.st_mode)) {
-			char lnk[256];
-			int len;
-			len = readlink(template, lnk, sizeof(lnk));
-			if (len < 0)
-				die_errno(_("cannot readlink '%s'"), template);
-			if (sizeof(lnk) <= len)
-				die(_("insanely long symlink %s"), template);
-			lnk[len] = 0;
-			if (symlink(lnk, path))
-				die_errno(_("cannot symlink '%s' '%s'"), lnk, path);
+			struct strbuf lnk = STRBUF_INIT;
+			if (strbuf_readlink(&lnk, template->buf, 0) < 0)
+				die_errno(_("cannot readlink '%s'"), template->buf);
+			if (symlink(lnk.buf, path->buf))
+				die_errno(_("cannot symlink '%s' '%s'"),
+					  lnk.buf, path->buf);
+			strbuf_release(&lnk);
 		}
 		else if (S_ISREG(st_template.st_mode)) {
-			if (copy_file(path, template, st_template.st_mode))
-				die_errno(_("cannot copy '%s' to '%s'"), template,
-					  path);
+			if (copy_file(path->buf, template->buf, st_template.st_mode))
+				die_errno(_("cannot copy '%s' to '%s'"),
+					  template->buf, path->buf);
 		}
 		else
-			error(_("ignoring template %s"), template);
+			error(_("ignoring template %s"), template->buf);
 	}
 }
 
 static void copy_templates(const char *template_dir)
 {
-	char path[PATH_MAX];
-	char template_path[PATH_MAX];
-	int template_len;
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf template_path = STRBUF_INIT;
+	size_t template_len;
 	DIR *dir;
-	const char *git_dir = get_git_dir();
-	int len = strlen(git_dir);
 	char *to_free = NULL;
 
 	if (!template_dir)
@@ -132,26 +120,23 @@ static void copy_templates(const char *template_dir)
 		free(to_free);
 		return;
 	}
-	template_len = strlen(template_dir);
-	if (PATH_MAX <= (template_len+strlen("/config")))
-		die(_("insanely long template path %s"), template_dir);
-	strcpy(template_path, template_dir);
-	if (template_path[template_len-1] != '/') {
-		template_path[template_len++] = '/';
-		template_path[template_len] = 0;
-	}
-	dir = opendir(template_path);
+
+	strbuf_addstr(&template_path, template_dir);
+	strbuf_complete(&template_path, '/');
+	template_len = template_path.len;
+
+	dir = opendir(template_path.buf);
 	if (!dir) {
 		warning(_("templates not found %s"), template_dir);
 		goto free_return;
 	}
 
 	/* Make sure that template is from the correct vintage */
-	strcpy(template_path + template_len, "config");
+	strbuf_addstr(&template_path, "config");
 	repository_format_version = 0;
 	git_config_from_file(check_repository_format_version,
-			     template_path, NULL);
-	template_path[template_len] = 0;
+			     template_path.buf, NULL);
+	strbuf_setlen(&template_path, template_len);
 
 	if (repository_format_version &&
 	    repository_format_version != GIT_REPO_VERSION) {
@@ -162,17 +147,15 @@ static void copy_templates(const char *template_dir)
 		goto close_free_return;
 	}
 
-	memcpy(path, git_dir, len);
-	if (len && path[len - 1] != '/')
-		path[len++] = '/';
-	path[len] = 0;
-	copy_templates_1(path, len,
-			 template_path, template_len,
-			 dir);
+	strbuf_addstr(&path, get_git_dir());
+	strbuf_complete(&path, '/');
+	copy_templates_1(&path, &template_path, dir);
 close_free_return:
 	closedir(dir);
 free_return:
 	free(to_free);
+	strbuf_release(&path);
+	strbuf_release(&template_path);
 }
 
 static int git_init_db_config(const char *k, const char *v, void *cb)
@@ -199,28 +182,20 @@ static int needs_work_tree_config(const char *git_dir, const char *work_tree)
 
 static int create_default_files(const char *template_path)
 {
-	const char *git_dir = get_git_dir();
-	unsigned len = strlen(git_dir);
-	static char path[PATH_MAX];
 	struct stat st1;
+	struct strbuf buf = STRBUF_INIT;
+	char *path;
 	char repo_version_string[10];
 	char junk[2];
 	int reinit;
 	int filemode;
 
-	if (len > sizeof(path)-50)
-		die(_("insane git directory %s"), git_dir);
-	memcpy(path, git_dir, len);
-
-	if (len && path[len-1] != '/')
-		path[len++] = '/';
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs"), 1);
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs/heads"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs/tags"), 1);
 
 	/* Just look for `init.templatedir` */
 	git_config(git_init_db_config, NULL);
@@ -244,16 +219,16 @@ static int create_default_files(const char *template_path)
 	 */
 	if (shared_repository) {
 		adjust_shared_perm(get_git_dir());
-		adjust_shared_perm(git_path("refs"));
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		adjust_shared_perm(git_path_buf(&buf, "refs"));
+		adjust_shared_perm(git_path_buf(&buf, "refs/heads"));
+		adjust_shared_perm(git_path_buf(&buf, "refs/tags"));
 	}
 
 	/*
 	 * Create the default symlink from ".git/HEAD" to the "master"
 	 * branch, if it does not exist yet.
 	 */
-	strcpy(path + len, "HEAD");
+	path = git_path_buf(&buf, "HEAD");
 	reinit = (!access(path, R_OK)
 		  || readlink(path, junk, sizeof(junk)-1) != -1);
 	if (!reinit) {
@@ -266,10 +241,8 @@ static int create_default_files(const char *template_path)
 		  "%d", GIT_REPO_VERSION);
 	git_config_set("core.repositoryformatversion", repo_version_string);
 
-	path[len] = 0;
-	strcpy(path + len, "config");
-
 	/* Check filemode trustability */
+	path = git_path_buf(&buf, "config");
 	filemode = TEST_FILEMODE;
 	if (TEST_FILEMODE && !lstat(path, &st1)) {
 		struct stat st2;
@@ -290,14 +263,13 @@ static int create_default_files(const char *template_path)
 		/* allow template config file to override the default */
 		if (log_all_ref_updates == -1)
 		    git_config_set("core.logallrefupdates", "true");
-		if (needs_work_tree_config(git_dir, work_tree))
+		if (needs_work_tree_config(get_git_dir(), work_tree))
 			git_config_set("core.worktree", work_tree);
 	}
 
 	if (!reinit) {
 		/* Check if symlink is supported in the work tree */
-		path[len] = 0;
-		strcpy(path + len, "tXXXXXX");
+		path = git_path_buf(&buf, "tXXXXXX");
 		if (!close(xmkstemp(path)) &&
 		    !unlink(path) &&
 		    !symlink("testing", path) &&
@@ -308,31 +280,35 @@ static int create_default_files(const char *template_path)
 			git_config_set("core.symlinks", "false");
 
 		/* Check if the filesystem is case-insensitive */
-		path[len] = 0;
-		strcpy(path + len, "CoNfIg");
+		path = git_path_buf(&buf, "CoNfIg");
 		if (!access(path, F_OK))
 			git_config_set("core.ignorecase", "true");
-		probe_utf8_pathname_composition(path, len);
+		probe_utf8_pathname_composition(path);
 	}
 
+	strbuf_release(&buf);
 	return reinit;
 }
 
 static void create_object_directory(void)
 {
-	const char *object_directory = get_object_directory();
-	int len = strlen(object_directory);
-	char *path = xmalloc(len + 40);
+	struct strbuf path = STRBUF_INIT;
+	size_t baselen;
+
+	strbuf_addstr(&path, get_object_directory());
+	baselen = path.len;
+
+	safe_create_dir(path.buf, 1);
 
-	memcpy(path, object_directory, len);
+	strbuf_setlen(&path, baselen);
+	strbuf_addstr(&path, "/pack");
+	safe_create_dir(path.buf, 1);
 
-	safe_create_dir(object_directory, 1);
-	strcpy(path+len, "/pack");
-	safe_create_dir(path, 1);
-	strcpy(path+len, "/info");
-	safe_create_dir(path, 1);
+	strbuf_setlen(&path, baselen);
+	strbuf_addstr(&path, "/info");
+	safe_create_dir(path.buf, 1);
 
-	free(path);
+	strbuf_release(&path);
 }
 
 int set_git_dir_init(const char *git_dir, const char *real_git_dir,
diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index 95fe849..b4dd3c7 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -36,24 +36,28 @@ static size_t has_non_ascii(const char *s, size_t maxlen, size_t *strlen_c)
 }
 
 
-void probe_utf8_pathname_composition(char *path, int len)
+void probe_utf8_pathname_composition(struct strbuf *path)
 {
 	static const char *auml_nfc = "\xc3\xa4";
 	static const char *auml_nfd = "\x61\xcc\x88";
+	size_t baselen = path->len;
 	int output_fd;
 	if (precomposed_unicode != -1)
 		return; /* We found it defined in the global config, respect it */
-	strcpy(path + len, auml_nfc);
+	strbuf_addstr(path, auml_nfc);
 	output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
 	if (output_fd >= 0) {
 		close(output_fd);
-		strcpy(path + len, auml_nfd);
+		strbuf_setlen(path, baselen);
+		strbuf_addstr(path, auml_nfd);
 		precomposed_unicode = access(path, R_OK) ? 0 : 1;
 		git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
-		strcpy(path + len, auml_nfc);
+		strbuf_setlen(path, baselen);
+		strbuf_addstr(path, auml_nfc);
 		if (unlink(path))
 			die_errno(_("failed to unlink '%s'"), path);
 	}
+	strbuf_setlen(path, baselen);
 }
 
 
diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
index 3b73585..7fc7be5 100644
--- a/compat/precompose_utf8.h
+++ b/compat/precompose_utf8.h
@@ -27,7 +27,7 @@ typedef struct {
 } PREC_DIR;
 
 void precompose_argv(int argc, const char **argv);
-void probe_utf8_pathname_composition(char *, int);
+void probe_utf8_pathname_composition(struct strbuf *path);
 
 PREC_DIR *precompose_utf8_opendir(const char *dirname);
 struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);
diff --git a/git-compat-util.h b/git-compat-util.h
index 348b9dc..712de7f 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -229,7 +229,7 @@ typedef unsigned long uintptr_t;
 #else
 #define precompose_str(in,i_nfd2nfc)
 #define precompose_argv(c,v)
-#define probe_utf8_pathname_composition(a,b)
+#define probe_utf8_pathname_composition(p)
 #endif
 
 #ifdef MKDIR_WO_TRAILING_SLASH
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 7de8d85..f91bbcf 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -202,8 +202,8 @@ test_expect_success 'init honors global core.sharedRepository' '
 	x$(git config -f shared-honor-global/.git/config core.sharedRepository)
 '
 
-test_expect_success 'init rejects insanely long --template' '
-	test_must_fail git init --template=$(printf "x%09999dx" 1) test
+test_expect_success 'init allows insanely long --template' '
+	git init --template=$(printf "x%09999dx" 1) test
 '
 
 test_expect_success 'init creates a new directory' '
-- 
2.6.0.rc3.454.g204ad51

[PATCH 42/68] apply: convert root string to strbuf

[Jeff King]

We use manual computation and strcpy to allocate the "root"
variable. This would be much simpler using xstrfmt.  But
since we store the length, too, we can just use a strbuf,
which handles that for us.

Note that we stop distinguishing between "no root" and
"empty root" in some cases, but that's OK; the results are
the same (e.g., inserting an empty string is a noop).

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/apply.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index 094a20f..1d4d439 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -77,8 +77,7 @@ static enum ws_ignore {
 
 
 static const char *patch_input_file;
-static const char *root;
-static int root_len;
+struct strbuf root = STRBUF_INIT;
 static int read_stdin = 1;
 static int options;
 
@@ -494,8 +493,8 @@ static char *find_name_gnu(const char *line, const char *def, int p_value)
 	}
 
 	strbuf_remove(&name, 0, cp - name.buf);
-	if (root)
-		strbuf_insert(&name, 0, root, root_len);
+	if (root.len)
+		strbuf_insert(&name, 0, root.buf, root.len);
 	return squash_slash(strbuf_detach(&name, NULL));
 }
 
@@ -697,8 +696,8 @@ static char *find_name_common(const char *line, const char *def,
 			return squash_slash(xstrdup(def));
 	}
 
-	if (root) {
-		char *ret = xstrfmt("%s%.*s", root, len, start);
+	if (root.len) {
+		char *ret = xstrfmt("%s%.*s", root.buf, len, start);
 		return squash_slash(ret);
 	}
 
@@ -1274,8 +1273,8 @@ static int parse_git_header(const char *line, int len, unsigned int size, struct
 	 * the default name from the header.
 	 */
 	patch->def_name = git_header_name(line, len);
-	if (patch->def_name && root) {
-		char *s = xstrfmt("%s%s", root, patch->def_name);
+	if (patch->def_name && root.len) {
+		char *s = xstrfmt("%s%s", root.buf, patch->def_name);
 		free(patch->def_name);
 		patch->def_name = s;
 	}
@@ -4498,14 +4497,9 @@ static int option_parse_whitespace(const struct option *opt,
 static int option_parse_directory(const struct option *opt,
 				  const char *arg, int unset)
 {
-	root_len = strlen(arg);
-	if (root_len && arg[root_len - 1] != '/') {
-		char *new_root;
-		root = new_root = xmalloc(root_len + 2);
-		strcpy(new_root, arg);
-		strcpy(new_root + root_len++, "/");
-	} else
-		root = arg;
+	strbuf_reset(&root);
+	strbuf_addstr(&root, arg);
+	strbuf_complete(&root, '/');
 	return 0;
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 43/68] transport: use strbufs for status table "quickref" strings

[Jeff King]

We generate range strings like "1234abcd...5678efab" for use
in the the fetch and push status tables. We use fixed-size
buffers along with strcat to do so. These aren't buggy, as
our manual size computation is correct, but there's nothing
checking that this is so.  Let's switch them to strbufs
instead, which are obviously correct, and make it easier to
audit the code base for problematic calls to strcat().

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fetch.c | 22 ++++++++++++----------
 transport.c     | 13 +++++++------
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 4703725..841880e 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -528,36 +528,38 @@ static int update_local_ref(struct ref *ref,
 	}
 
 	if (in_merge_bases(current, updated)) {
-		char quickref[83];
+		struct strbuf quickref = STRBUF_INIT;
 		int r;
-		strcpy(quickref, find_unique_abbrev(current->object.sha1, DEFAULT_ABBREV));
-		strcat(quickref, "..");
-		strcat(quickref, find_unique_abbrev(ref->new_sha1, DEFAULT_ABBREV));
+		strbuf_add_unique_abbrev(&quickref, current->object.sha1, DEFAULT_ABBREV);
+		strbuf_addstr(&quickref, "..");
+		strbuf_add_unique_abbrev(&quickref, ref->new_sha1, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
 			check_for_new_submodule_commits(ref->new_sha1);
 		r = s_update_ref("fast-forward", ref, 1);
 		strbuf_addf(display, "%c %-*s %-*s -> %s%s",
 			    r ? '!' : ' ',
-			    TRANSPORT_SUMMARY_WIDTH, quickref,
+			    TRANSPORT_SUMMARY_WIDTH, quickref.buf,
 			    REFCOL_WIDTH, remote, pretty_ref,
 			    r ? _("  (unable to update local ref)") : "");
+		strbuf_release(&quickref);
 		return r;
 	} else if (force || ref->force) {
-		char quickref[84];
+		struct strbuf quickref = STRBUF_INIT;
 		int r;
-		strcpy(quickref, find_unique_abbrev(current->object.sha1, DEFAULT_ABBREV));
-		strcat(quickref, "...");
-		strcat(quickref, find_unique_abbrev(ref->new_sha1, DEFAULT_ABBREV));
+		strbuf_add_unique_abbrev(&quickref, current->object.sha1, DEFAULT_ABBREV);
+		strbuf_addstr(&quickref, "...");
+		strbuf_add_unique_abbrev(&quickref, ref->new_sha1, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
 			check_for_new_submodule_commits(ref->new_sha1);
 		r = s_update_ref("forced-update", ref, 1);
 		strbuf_addf(display, "%c %-*s %-*s -> %s  (%s)",
 			    r ? '!' : '+',
-			    TRANSPORT_SUMMARY_WIDTH, quickref,
+			    TRANSPORT_SUMMARY_WIDTH, quickref.buf,
 			    REFCOL_WIDTH, remote, pretty_ref,
 			    r ? _("unable to update local ref") : _("forced update"));
+		strbuf_release(&quickref);
 		return r;
 	} else {
 		strbuf_addf(display, "! %-*s %-*s -> %s  %s",
diff --git a/transport.c b/transport.c
index 2d51348..3b47d49 100644
--- a/transport.c
+++ b/transport.c
@@ -654,23 +654,24 @@ static void print_ok_ref_status(struct ref *ref, int porcelain)
 			"[new branch]"),
 			ref, ref->peer_ref, NULL, porcelain);
 	else {
-		char quickref[84];
+		struct strbuf quickref = STRBUF_INIT;
 		char type;
 		const char *msg;
 
-		strcpy(quickref, status_abbrev(ref->old_sha1));
+		strbuf_addstr(&quickref, status_abbrev(ref->old_sha1));
 		if (ref->forced_update) {
-			strcat(quickref, "...");
+			strbuf_addstr(&quickref, "...");
 			type = '+';
 			msg = "forced update";
 		} else {
-			strcat(quickref, "..");
+			strbuf_addstr(&quickref, "..");
 			type = ' ';
 			msg = NULL;
 		}
-		strcat(quickref, status_abbrev(ref->new_sha1));
+		strbuf_addstr(&quickref, status_abbrev(ref->new_sha1));
 
-		print_ref_status(type, quickref, ref, ref->peer_ref, msg, porcelain);
+		print_ref_status(type, quickref.buf, ref, ref->peer_ref, msg, porcelain);
+		strbuf_release(&quickref);
 	}
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 44/68] merge-recursive: convert malloc / strcpy to strbuf

[Jeff King]

This would be a fairly routine use of xstrfmt, except that
we need to remember the length of the result to pass to
cache_name_pos. So just use a strbuf, which makes this
simple.

As a bonus, this gets rid of confusing references to
"pathlen+1". The "1" is for the trailing slash we added, but
that is automatically accounted for in the strbuf's len
parameter.

Signed-off-by: Jeff King <peff@peff.net>
---
 merge-recursive.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 44d85be..a5e74d8 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -630,25 +630,24 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
 
 static int dir_in_way(const char *path, int check_working_copy)
 {
-	int pos, pathlen = strlen(path);
-	char *dirpath = xmalloc(pathlen + 2);
+	int pos;
+	struct strbuf dirpath = STRBUF_INIT;
 	struct stat st;
 
-	strcpy(dirpath, path);
-	dirpath[pathlen] = '/';
-	dirpath[pathlen+1] = '\0';
+	strbuf_addstr(&dirpath, path);
+	strbuf_addch(&dirpath, '/');
 
-	pos = cache_name_pos(dirpath, pathlen+1);
+	pos = cache_name_pos(dirpath.buf, dirpath.len);
 
 	if (pos < 0)
 		pos = -1 - pos;
 	if (pos < active_nr &&
-	    !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
-		free(dirpath);
+	    !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
+		strbuf_release(&dirpath);
 		return 1;
 	}
 
-	free(dirpath);
+	strbuf_release(&dirpath);
 	return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 45/68] enter_repo: convert fixed-size buffers to strbufs

[Jeff King]

We use two PATH_MAX-sized buffers to represent the repo
path, and must make sure not to overflow them. We do take
care to check the lengths, but the logic is rather hard to
follow, as we use several magic numbers (e.g., "PATH_MAX -
10"). And in fact you _can_ overflow the buffer if you have
a ".git" file with an extremely long path in it.

By switching to strbufs, these problems all go away. We do,
however, retain the check that the initial input we get is
no larger than PATH_MAX. This function is an entry point for
untrusted repo names from the network, and it's a good idea
to keep a sanity check (both to avoid allocating arbitrary
amounts of memory, and also as a layer of defense against
any downstream users of the names).

Signed-off-by: Jeff King <peff@peff.net>
---
 path.c | 57 +++++++++++++++++++++++++++++----------------------------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/path.c b/path.c
index 46a4d27..60e0390 100644
--- a/path.c
+++ b/path.c
@@ -391,8 +391,8 @@ return_null:
  */
 const char *enter_repo(const char *path, int strict)
 {
-	static char used_path[PATH_MAX];
-	static char validated_path[PATH_MAX];
+	static struct strbuf validated_path = STRBUF_INIT;
+	static struct strbuf used_path = STRBUF_INIT;
 
 	if (!path)
 		return NULL;
@@ -407,46 +407,47 @@ const char *enter_repo(const char *path, int strict)
 		while ((1 < len) && (path[len-1] == '/'))
 			len--;
 
+		/*
+		 * We can handle arbitrary-sized buffers, but this remains as a
+		 * sanity check on untrusted input.
+		 */
 		if (PATH_MAX <= len)
 			return NULL;
-		strncpy(used_path, path, len); used_path[len] = 0 ;
-		strcpy(validated_path, used_path);
 
-		if (used_path[0] == '~') {
-			char *newpath = expand_user_path(used_path);
-			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
-				free(newpath);
+		strbuf_reset(&used_path);
+		strbuf_reset(&validated_path);
+		strbuf_add(&used_path, path, len);
+		strbuf_add(&validated_path, path, len);
+
+		if (used_path.buf[0] == '~') {
+			char *newpath = expand_user_path(used_path.buf);
+			if (!newpath)
 				return NULL;
-			}
-			/*
-			 * Copy back into the static buffer. A pity
-			 * since newpath was not bounded, but other
-			 * branches of the if are limited by PATH_MAX
-			 * anyway.
-			 */
-			strcpy(used_path, newpath); free(newpath);
+			strbuf_attach(&used_path, newpath, strlen(newpath),
+				      strlen(newpath));
 		}
-		else if (PATH_MAX - 10 < len)
-			return NULL;
-		len = strlen(used_path);
 		for (i = 0; suffix[i]; i++) {
 			struct stat st;
-			strcpy(used_path + len, suffix[i]);
-			if (!stat(used_path, &st) &&
+			size_t baselen = used_path.len;
+			strbuf_addstr(&used_path, suffix[i]);
+			if (!stat(used_path.buf, &st) &&
 			    (S_ISREG(st.st_mode) ||
-			    (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
-				strcat(validated_path, suffix[i]);
+			    (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
+				strbuf_addstr(&validated_path, suffix[i]);
 				break;
 			}
+			strbuf_setlen(&used_path, baselen);
 		}
 		if (!suffix[i])
 			return NULL;
-		gitfile = read_gitfile(used_path) ;
-		if (gitfile)
-			strcpy(used_path, gitfile);
-		if (chdir(used_path))
+		gitfile = read_gitfile(used_path.buf) ;
+		if (gitfile) {
+			strbuf_reset(&used_path);
+			strbuf_addstr(&used_path, gitfile);
+		}
+		if (chdir(used_path.buf))
 			return NULL;
-		path = validated_path;
+		path = validated_path.buf;
 	}
 	else if (chdir(path))
 		return NULL;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 46/68] remove_leading_path: use a strbuf for internal storage

[Jeff King]

This function strcpy's directly into a PATH_MAX-sized
buffer. There's only one caller, which feeds the git_dir into
it, so it's not easy to trigger in practice (even if you fed
a large $GIT_DIR through the environment or .git file, it
would have to actually exist and be accessible on the
filesystem to get to this point). We can fix it by moving to
a strbuf.

Signed-off-by: Jeff King <peff@peff.net>
---
 path.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/path.c b/path.c
index 60e0390..c597473 100644
--- a/path.c
+++ b/path.c
@@ -632,7 +632,7 @@ const char *relative_path(const char *in, const char *prefix,
  */
 const char *remove_leading_path(const char *in, const char *prefix)
 {
-	static char buf[PATH_MAX + 1];
+	static struct strbuf buf = STRBUF_INIT;
 	int i = 0, j = 0;
 
 	if (!prefix || !prefix[0])
@@ -661,11 +661,13 @@ const char *remove_leading_path(const char *in, const char *prefix)
 		return in;
 	while (is_dir_sep(in[j]))
 		j++;
+
+	strbuf_reset(&buf);
 	if (!in[j])
-		strcpy(buf, ".");
+		strbuf_addstr(&buf, ".");
 	else
-		strcpy(buf, in + j);
-	return buf;
+		strbuf_addstr(&buf, in + j);
+	return buf.buf;
 }
 
 /*
-- 
2.6.0.rc3.454.g204ad51

[PATCH 47/68] write_loose_object: convert to strbuf

[Jeff King]

When creating a loose object tempfile, we use a fixed
PATH_MAX-sized buffer, and strcpy directly into it. This
isn't buggy, because we do a rough check of the size, but
there's no verification that our guesstimate of the required
space is enough (in fact, it's several bytes too big for the
current naming scheme).

Let's switch to a strbuf, which makes this much easier to
verify. The allocation overhead should be negligible, since
we are replacing a static buffer with a static strbuf, and
we'll only need to allocate on the first call.

While we're here, we can also document a subtle interaction
with mkstemp that would be easy to overlook.

Signed-off-by: Jeff King <peff@peff.net>
---
 sha1_file.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index c26fdcb..4211af1 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -3011,29 +3011,31 @@ static inline int directory_size(const char *filename)
  * We want to avoid cross-directory filename renames, because those
  * can have problems on various filesystems (FAT, NFS, Coda).
  */
-static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
+static int create_tmpfile(struct strbuf *tmp, const char *filename)
 {
 	int fd, dirlen = directory_size(filename);
 
-	if (dirlen + 20 > bufsiz) {
-		errno = ENAMETOOLONG;
-		return -1;
-	}
-	memcpy(buffer, filename, dirlen);
-	strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
-	fd = git_mkstemp_mode(buffer, 0444);
+	strbuf_reset(tmp);
+	strbuf_add(tmp, filename, dirlen);
+	strbuf_addstr(tmp, "tmp_obj_XXXXXX");
+	fd = git_mkstemp_mode(tmp->buf, 0444);
 	if (fd < 0 && dirlen && errno == ENOENT) {
-		/* Make sure the directory exists */
-		memcpy(buffer, filename, dirlen);
-		buffer[dirlen-1] = 0;
-		if (mkdir(buffer, 0777) && errno != EEXIST)
+		/*
+		 * Make sure the directory exists; note that the contents
+		 * of the buffer are undefined after mkstemp returns an
+		 * error, so we have to rewrite the whole buffer from
+		 * scratch.
+		 */
+		strbuf_reset(tmp);
+		strbuf_add(tmp, filename, dirlen - 1);
+		if (mkdir(tmp->buf, 0777) && errno != EEXIST)
 			return -1;
-		if (adjust_shared_perm(buffer))
+		if (adjust_shared_perm(tmp->buf))
 			return -1;
 
 		/* Try again */
-		strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
-		fd = git_mkstemp_mode(buffer, 0444);
+		strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
+		fd = git_mkstemp_mode(tmp->buf, 0444);
 	}
 	return fd;
 }
@@ -3046,10 +3048,10 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 	git_zstream stream;
 	git_SHA_CTX c;
 	unsigned char parano_sha1[20];
-	static char tmp_file[PATH_MAX];
+	static struct strbuf tmp_file = STRBUF_INIT;
 	const char *filename = sha1_file_name(sha1);
 
-	fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
+	fd = create_tmpfile(&tmp_file, filename);
 	if (fd < 0) {
 		if (errno == EACCES)
 			return error("insufficient permission for adding an object to repository database %s", get_object_directory());
@@ -3098,12 +3100,12 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 		struct utimbuf utb;
 		utb.actime = mtime;
 		utb.modtime = mtime;
-		if (utime(tmp_file, &utb) < 0)
+		if (utime(tmp_file.buf, &utb) < 0)
 			warning("failed utime() on %s: %s",
-				tmp_file, strerror(errno));
+				tmp_file.buf, strerror(errno));
 	}
 
-	return finalize_object_file(tmp_file, filename);
+	return finalize_object_file(tmp_file.buf, filename);
 }
 
 static int freshen_loose_object(const unsigned char *sha1)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 48/68] diagnose_invalid_index_path: use strbuf to avoid strcpy/strcat

[Jeff King]

We dynamically allocate a buffer and then strcpy and strcat
into it. This isn't buggy, but we'd prefer to avoid these
suspicious functions.

This would be a good candidate for converstion to xstrfmt,
but we need to record the length for dealing with index
entries. A strbuf handles that for us.

Signed-off-by: Jeff King <peff@peff.net>
---
 sha1_name.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/sha1_name.c b/sha1_name.c
index 80753b6..3242c5e 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1293,8 +1293,7 @@ static void diagnose_invalid_index_path(int stage,
 	const struct cache_entry *ce;
 	int pos;
 	unsigned namelen = strlen(filename);
-	unsigned fullnamelen;
-	char *fullname;
+	struct strbuf fullname = STRBUF_INIT;
 
 	if (!prefix)
 		prefix = "";
@@ -1314,21 +1313,19 @@ static void diagnose_invalid_index_path(int stage,
 	}
 
 	/* Confusion between relative and absolute filenames? */
-	fullnamelen = namelen + strlen(prefix);
-	fullname = xmalloc(fullnamelen + 1);
-	strcpy(fullname, prefix);
-	strcat(fullname, filename);
-	pos = cache_name_pos(fullname, fullnamelen);
+	strbuf_addstr(&fullname, prefix);
+	strbuf_addstr(&fullname, filename);
+	pos = cache_name_pos(fullname.buf, fullname.len);
 	if (pos < 0)
 		pos = -pos - 1;
 	if (pos < active_nr) {
 		ce = active_cache[pos];
-		if (ce_namelen(ce) == fullnamelen &&
-		    !memcmp(ce->name, fullname, fullnamelen))
+		if (ce_namelen(ce) == fullname.len &&
+		    !memcmp(ce->name, fullname.buf, fullname.len))
 			die("Path '%s' is in the index, but not '%s'.\n"
 			    "Did you mean ':%d:%s' aka ':%d:./%s'?",
-			    fullname, filename,
-			    ce_stage(ce), fullname,
+			    fullname.buf, filename,
+			    ce_stage(ce), fullname.buf,
 			    ce_stage(ce), filename);
 	}
 
@@ -1338,7 +1335,7 @@ static void diagnose_invalid_index_path(int stage,
 		die("Path '%s' does not exist (neither on disk nor in the index).",
 		    filename);
 
-	free(fullname);
+	strbuf_release(&fullname);
 }
 
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 49/68] fetch-pack: use argv_array for index-pack / unpack-objects

[Jeff King]

This cleans up a magic number that must be kept in sync with
the rest of the code (the number of argv slots). It also
lets us drop some fixed buffers and an sprintf (since we
can now use argv_array_pushf).

We do still have to keep one fixed buffer for calling
gethostname, but at least now the size computations for it
are much simpler.

Signed-off-by: Jeff King <peff@peff.net>
---
 fetch-pack.c | 56 +++++++++++++++++++++++++++-----------------------------
 1 file changed, 27 insertions(+), 29 deletions(-)

diff --git a/fetch-pack.c b/fetch-pack.c
index 820251a..2dabee9 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -681,11 +681,10 @@ static int get_pack(struct fetch_pack_args *args,
 		    int xd[2], char **pack_lockfile)
 {
 	struct async demux;
-	const char *argv[22];
-	char keep_arg[256];
-	char hdr_arg[256];
-	const char **av, *cmd_name;
 	int do_keep = args->keep_pack;
+	const char *cmd_name;
+	struct pack_header header;
+	int pass_header = 0;
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	int ret;
 
@@ -705,17 +704,11 @@ static int get_pack(struct fetch_pack_args *args,
 	else
 		demux.out = xd[0];
 
-	cmd.argv = argv;
-	av = argv;
-	*hdr_arg = 0;
 	if (!args->keep_pack && unpack_limit) {
-		struct pack_header header;
 
 		if (read_pack_header(demux.out, &header))
 			die("protocol error: bad pack header");
-		snprintf(hdr_arg, sizeof(hdr_arg),
-			 "--pack_header=%"PRIu32",%"PRIu32,
-			 ntohl(header.hdr_version), ntohl(header.hdr_entries));
+		pass_header = 1;
 		if (ntohl(header.hdr_entries) < unpack_limit)
 			do_keep = 0;
 		else
@@ -723,44 +716,49 @@ static int get_pack(struct fetch_pack_args *args,
 	}
 
 	if (alternate_shallow_file) {
-		*av++ = "--shallow-file";
-		*av++ = alternate_shallow_file;
+		argv_array_push(&cmd.args, "--shallow-file");
+		argv_array_push(&cmd.args, alternate_shallow_file);
 	}
 
 	if (do_keep) {
 		if (pack_lockfile)
 			cmd.out = -1;
-		*av++ = cmd_name = "index-pack";
-		*av++ = "--stdin";
+		cmd_name = "index-pack";
+		argv_array_push(&cmd.args, cmd_name);
+		argv_array_push(&cmd.args, "--stdin");
 		if (!args->quiet && !args->no_progress)
-			*av++ = "-v";
+			argv_array_push(&cmd.args, "-v");
 		if (args->use_thin_pack)
-			*av++ = "--fix-thin";
+			argv_array_push(&cmd.args, "--fix-thin");
 		if (args->lock_pack || unpack_limit) {
-			int s = sprintf(keep_arg,
-					"--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
-			if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
-				strcpy(keep_arg + s, "localhost");
-			*av++ = keep_arg;
+			char hostname[256];
+			if (gethostname(hostname, sizeof(hostname)))
+				xsnprintf(hostname, sizeof(hostname), "localhost");
+			argv_array_pushf(&cmd.args,
+					"--keep=fetch-pack %"PRIuMAX " on %s",
+					(uintmax_t)getpid(), hostname);
 		}
 		if (args->check_self_contained_and_connected)
-			*av++ = "--check-self-contained-and-connected";
+			argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 	}
 	else {
-		*av++ = cmd_name = "unpack-objects";
+		cmd_name = "unpack-objects";
+		argv_array_push(&cmd.args, cmd_name);
 		if (args->quiet || args->no_progress)
-			*av++ = "-q";
+			argv_array_push(&cmd.args, "-q");
 		args->check_self_contained_and_connected = 0;
 	}
-	if (*hdr_arg)
-		*av++ = hdr_arg;
+
+	if (pass_header)
+		argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
+				 ntohl(header.hdr_version),
+				 ntohl(header.hdr_entries));
 	if (fetch_fsck_objects >= 0
 	    ? fetch_fsck_objects
 	    : transfer_fsck_objects >= 0
 	    ? transfer_fsck_objects
 	    : 0)
-		*av++ = "--strict";
-	*av++ = NULL;
+		argv_array_push(&cmd.args, "--strict");
 
 	cmd.in = demux.out;
 	cmd.git_cmd = 1;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 50/68] http-push: use an argv_array for setup_revisions

[Jeff King]

This drops the magic number for the fixed-size argv arrays,
so we do not have to wonder if we are overflowing it. We can
also drop some confusing sha1_to_hex memory allocation
(which seems to predate the ring of buffers allowing
multiple calls), and get rid of an unchecked sprintf call.

Signed-off-by: Jeff King <peff@peff.net>
---
 http-push.c | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/http-push.c b/http-push.c
index e501c28..43a9036 100644
--- a/http-push.c
+++ b/http-push.c
@@ -10,6 +10,7 @@
 #include "remote.h"
 #include "list-objects.h"
 #include "sigchain.h"
+#include "argv-array.h"
 
 #ifdef EXPAT_NEEDS_XMLPARSE_H
 #include <xmlparse.h>
@@ -1856,9 +1857,7 @@ int main(int argc, char **argv)
 	new_refs = 0;
 	for (ref = remote_refs; ref; ref = ref->next) {
 		char old_hex[60], *new_hex;
-		const char *commit_argv[5];
-		int commit_argc;
-		char *new_sha1_hex, *old_sha1_hex;
+		struct argv_array commit_argv = ARGV_ARRAY_INIT;
 
 		if (!ref->peer_ref)
 			continue;
@@ -1937,27 +1936,15 @@ int main(int argc, char **argv)
 		}
 
 		/* Set up revision info for this refspec */
-		commit_argc = 3;
-		new_sha1_hex = xstrdup(sha1_to_hex(ref->new_sha1));
-		old_sha1_hex = NULL;
-		commit_argv[1] = "--objects";
-		commit_argv[2] = new_sha1_hex;
-		if (!push_all && !is_null_sha1(ref->old_sha1)) {
-			old_sha1_hex = xmalloc(42);
-			sprintf(old_sha1_hex, "^%s",
-				sha1_to_hex(ref->old_sha1));
-			commit_argv[3] = old_sha1_hex;
-			commit_argc++;
-		}
-		commit_argv[commit_argc] = NULL;
+		argv_array_push(&commit_argv, ""); /* ignored */
+		argv_array_push(&commit_argv, "--objects");
+		argv_array_push(&commit_argv, sha1_to_hex(ref->new_sha1));
+		if (!push_all && !is_null_sha1(ref->old_sha1))
+			argv_array_pushf(&commit_argv, "^%s",
+					 sha1_to_hex(ref->old_sha1));
 		init_revisions(&revs, setup_git_directory());
-		setup_revisions(commit_argc, commit_argv, &revs, NULL);
+		setup_revisions(commit_argv.argc, commit_argv.argv, &revs, NULL);
 		revs.edge_hint = 0; /* just in case */
-		free(new_sha1_hex);
-		if (old_sha1_hex) {
-			free(old_sha1_hex);
-			commit_argv[1] = NULL;
-		}
 
 		/* Generate a list of objects that need to be pushed */
 		pushing = 0;
@@ -1986,6 +1973,7 @@ int main(int argc, char **argv)
 			printf("%s %s\n", !rc ? "ok" : "error", ref->name);
 		unlock_remote(ref_lock);
 		check_locks();
+		argv_array_clear(&commit_argv);
 	}
 
 	/* Update remote server info if appropriate */
-- 
2.6.0.rc3.454.g204ad51

[PATCH 51/68] stat_tracking_info: convert to argv_array

[Jeff King]

In addition to dropping the magic number for the fixed-size
argv, we can also drop a fixed-length buffer and some
strcpy's into it.

Signed-off-by: Jeff King <peff@peff.net>
---
 remote.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/remote.c b/remote.c
index a01f13a..1101f82 100644
--- a/remote.c
+++ b/remote.c
@@ -8,6 +8,7 @@
 #include "tag.h"
 #include "string-list.h"
 #include "mergesort.h"
+#include "argv-array.h"
 
 enum map_direction { FROM_SRC, FROM_DST };
 
@@ -1997,10 +1998,9 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 {
 	unsigned char sha1[20];
 	struct commit *ours, *theirs;
-	char symmetric[84];
 	struct rev_info revs;
-	const char *rev_argv[10], *base;
-	int rev_argc;
+	const char *base;
+	struct argv_array argv = ARGV_ARRAY_INIT;
 
 	/* Cannot stat unless we are marked to build on top of somebody else. */
 	base = branch_get_upstream(branch, NULL);
@@ -2029,19 +2029,15 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 	}
 
 	/* Run "rev-list --left-right ours...theirs" internally... */
-	rev_argc = 0;
-	rev_argv[rev_argc++] = NULL;
-	rev_argv[rev_argc++] = "--left-right";
-	rev_argv[rev_argc++] = symmetric;
-	rev_argv[rev_argc++] = "--";
-	rev_argv[rev_argc] = NULL;
-
-	strcpy(symmetric, sha1_to_hex(ours->object.sha1));
-	strcpy(symmetric + 40, "...");
-	strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
+	argv_array_push(&argv, ""); /* ignored */
+	argv_array_push(&argv, "--left-right");
+	argv_array_pushf(&argv, "%s...%s",
+			 sha1_to_hex(ours->object.sha1),
+			 sha1_to_hex(theirs->object.sha1));
+	argv_array_push(&argv, "--");
 
 	init_revisions(&revs, NULL);
-	setup_revisions(rev_argc, rev_argv, &revs, NULL);
+	setup_revisions(argv.argc, argv.argv, &revs, NULL);
 	if (prepare_revision_walk(&revs))
 		die("revision walk setup failed");
 
@@ -2061,6 +2057,8 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 	/* clear object flags smudged by the above traversal */
 	clear_commit_marks(ours, ALL_REV_FLAGS);
 	clear_commit_marks(theirs, ALL_REV_FLAGS);
+
+	argv_array_clear(&argv);
 	return 0;
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 52/68] daemon: use cld->env_array when re-spawning

[Jeff King]

This avoids an ugly strcat into a fixed-size buffer. It's
not wrong (the buffer is plenty large enough for an IPv6
address plus some minor formatting), but it takes some
effort to verify that.

Unfortunately we are still stuck with some fixed-size
buffers to hold the output of inet_ntop. But at least we now
pass very easy-to-verify parameters, rather than doing a
manual computation to account for other data in the buffer.

As a side effect, this also fixes the case where we might
pass an uninitialized portbuf buffer through the
environment. This probably couldn't happen in practice, as
it would mean that addr->sa_family was neither AF_INET nor
AF_INET6 (and that is all we are listening on).

Signed-off-by: Jeff King <peff@peff.net>
---
 daemon.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/daemon.c b/daemon.c
index 5218a3f..56679a1 100644
--- a/daemon.c
+++ b/daemon.c
@@ -811,8 +811,6 @@ static char **cld_argv;
 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 {
 	struct child_process cld = CHILD_PROCESS_INIT;
-	char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
-	char *env[] = { addrbuf, portbuf, NULL };
 
 	if (max_connections && live_children >= max_connections) {
 		kill_some_child();
@@ -826,27 +824,23 @@ static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 	}
 
 	if (addr->sa_family == AF_INET) {
+		char buf[128] = "";
 		struct sockaddr_in *sin_addr = (void *) addr;
-		inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
-		    sizeof(addrbuf) - 12);
-		snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
-		    ntohs(sin_addr->sin_port));
+		inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
+		argv_array_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
+		argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
+				 ntohs(sin_addr->sin_port));
 #ifndef NO_IPV6
 	} else if (addr->sa_family == AF_INET6) {
+		char buf[128] = "";
 		struct sockaddr_in6 *sin6_addr = (void *) addr;
-
-		char *buf = addrbuf + 12;
-		*buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
-		inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
-		    sizeof(addrbuf) - 13);
-		strcat(buf, "]");
-
-		snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
-		    ntohs(sin6_addr->sin6_port));
+		inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
+		argv_array_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
+		argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
+				 ntohs(sin6_addr->sin6_port));
 #endif
 	}
 
-	cld.env = (const char **)env;
 	cld.argv = (const char **)cld_argv;
 	cld.in = incoming;
 	cld.out = dup(incoming);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 53/68] use sha1_to_hex_r() instead of strcpy

[Jeff King]

Before sha1_to_hex_r() existed, a simple way to get hex
sha1 into a buffer was with:

  strcpy(buf, sha1_to_hex(sha1));

This isn't wrong (assuming the buf is 41 characters), but it
makes auditing the code base for bad strcpy() calls harder,
as these become false positives.

Let's convert them to sha1_to_hex_r(), and likewise for
some calls to find_unique_abbrev(). While we're here, we'll
double-check that all of the buffers are correctly sized,
and use the more obvious GIT_SHA1_HEXSZ constant.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/blame.c        |  8 ++++----
 builtin/merge-index.c  |  4 ++--
 builtin/merge.c        | 20 ++++++++++----------
 builtin/receive-pack.c | 15 +++++++++------
 builtin/rev-list.c     |  4 ++--
 diff.c                 |  9 ++++-----
 6 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/builtin/blame.c b/builtin/blame.c
index 4db01c1..e253ac0 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1867,9 +1867,9 @@ static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
 	int cnt;
 	const char *cp;
 	struct origin *suspect = ent->suspect;
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 
-	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+	sha1_to_hex_r(hex, suspect->commit->object.sha1);
 	printf("%s %d %d %d\n",
 	       hex,
 	       ent->s_lno + 1,
@@ -1905,11 +1905,11 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	const char *cp;
 	struct origin *suspect = ent->suspect;
 	struct commit_info ci;
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 
 	get_commit_info(suspect->commit, &ci, 1);
-	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+	sha1_to_hex_r(hex, suspect->commit->object.sha1);
 
 	cp = nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
diff --git a/builtin/merge-index.c b/builtin/merge-index.c
index 1d66111..1c3427c 100644
--- a/builtin/merge-index.c
+++ b/builtin/merge-index.c
@@ -9,7 +9,7 @@ static int merge_entry(int pos, const char *path)
 {
 	int found;
 	const char *arguments[] = { pgm, "", "", "", path, "", "", "", NULL };
-	char hexbuf[4][60];
+	char hexbuf[4][GIT_SHA1_HEXSZ + 1];
 	char ownbuf[4][60];
 
 	if (pos >= active_nr)
@@ -22,7 +22,7 @@ static int merge_entry(int pos, const char *path)
 		if (strcmp(ce->name, path))
 			break;
 		found++;
-		strcpy(hexbuf[stage], sha1_to_hex(ce->sha1));
+		sha1_to_hex_r(hexbuf[stage], ce->sha1);
 		xsnprintf(ownbuf[stage], sizeof(ownbuf[stage]), "%o", ce->ce_mode);
 		arguments[stage] = hexbuf[stage];
 		arguments[stage + 4] = ownbuf[stage];
diff --git a/builtin/merge.c b/builtin/merge.c
index a0edaca..a0a9328 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1319,13 +1319,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	if (verify_signatures) {
 		for (p = remoteheads; p; p = p->next) {
 			struct commit *commit = p->item;
-			char hex[41];
+			char hex[GIT_SHA1_HEXSZ + 1];
 			struct signature_check signature_check;
 			memset(&signature_check, 0, sizeof(signature_check));
 
 			check_commit_signature(commit, &signature_check);
 
-			strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+			find_unique_abbrev_r(hex, commit->object.sha1, DEFAULT_ABBREV);
 			switch (signature_check.result) {
 			case 'G':
 				break;
@@ -1415,15 +1415,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		/* Again the most common case of merging one remote. */
 		struct strbuf msg = STRBUF_INIT;
 		struct commit *commit;
-		char hex[41];
 
-		strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
-
-		if (verbosity >= 0)
-			printf(_("Updating %s..%s\n"),
-				hex,
-				find_unique_abbrev(remoteheads->item->object.sha1,
-				DEFAULT_ABBREV));
+		if (verbosity >= 0) {
+			char from[GIT_SHA1_HEXSZ + 1], to[GIT_SHA1_HEXSZ + 1];
+			find_unique_abbrev_r(from, head_commit->object.sha1,
+					      DEFAULT_ABBREV);
+			find_unique_abbrev_r(to, remoteheads->item->object.sha1,
+					      DEFAULT_ABBREV);
+			printf(_("Updating %s..%s\n"), from, to);
+		}
 		strbuf_addstr(&msg, "Fast-forward");
 		if (have_message)
 			strbuf_addstr(&msg,
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 04d2bdf..39eb064 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1071,8 +1071,11 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	const char *dst_name;
 	struct string_list_item *item;
 	struct command *dst_cmd;
-	unsigned char sha1[20];
-	char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
+	unsigned char sha1[GIT_SHA1_RAWSZ];
+	char cmd_oldh[GIT_SHA1_HEXSZ + 1],
+	     cmd_newh[GIT_SHA1_HEXSZ + 1],
+	     dst_oldh[GIT_SHA1_HEXSZ + 1],
+	     dst_newh[GIT_SHA1_HEXSZ + 1];
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
@@ -1103,10 +1106,10 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 
 	dst_cmd->skip_update = 1;
 
-	strcpy(cmd_oldh, find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV));
-	strcpy(cmd_newh, find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV));
-	strcpy(dst_oldh, find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV));
-	strcpy(dst_newh, find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
+	find_unique_abbrev_r(cmd_oldh, cmd->old_sha1, DEFAULT_ABBREV);
+	find_unique_abbrev_r(cmd_newh, cmd->new_sha1, DEFAULT_ABBREV);
+	find_unique_abbrev_r(dst_oldh, dst_cmd->old_sha1, DEFAULT_ABBREV);
+	find_unique_abbrev_r(dst_newh, dst_cmd->new_sha1, DEFAULT_ABBREV);
 	rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 		 " its target '%s' (%s..%s)",
 		 cmd->ref_name, cmd_oldh, cmd_newh,
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index d80d1ed..491d298 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -217,7 +217,7 @@ static void print_var_int(const char *var, int val)
 static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
 {
 	int cnt, flags = info->flags;
-	char hex[41] = "";
+	char hex[GIT_SHA1_HEXSZ + 1] = "";
 	struct commit_list *tried;
 	struct rev_info *revs = info->revs;
 
@@ -242,7 +242,7 @@ static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
 		cnt = reaches;
 
 	if (revs->commits)
-		strcpy(hex, sha1_to_hex(revs->commits->item->object.sha1));
+		sha1_to_hex_r(hex, revs->commits->item->object.sha1);
 
 	if (flags & BISECT_SHOW_ALL) {
 		traverse_commit_list(revs, show_commit, show_object, info);
diff --git a/diff.c b/diff.c
index 788e371..2a37378 100644
--- a/diff.c
+++ b/diff.c
@@ -322,7 +322,7 @@ static struct diff_tempfile {
 	 */
 	const char *name;
 
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 	char mode[10];
 
 	/*
@@ -2878,8 +2878,7 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 		die_errno("unable to write temp-file");
 	close_tempfile(&temp->tempfile);
 	temp->name = get_tempfile_path(&temp->tempfile);
-	strcpy(temp->hex, sha1_to_hex(sha1));
-	temp->hex[40] = 0;
+	sha1_to_hex_r(temp->hex, sha1);
 	xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
 	strbuf_release(&buf);
 	strbuf_release(&template);
@@ -2926,9 +2925,9 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 			/* we can borrow from the file in the work tree */
 			temp->name = name;
 			if (!one->sha1_valid)
-				strcpy(temp->hex, sha1_to_hex(null_sha1));
+				sha1_to_hex_r(temp->hex, null_sha1);
 			else
-				strcpy(temp->hex, sha1_to_hex(one->sha1));
+				sha1_to_hex_r(temp->hex, one->sha1);
 			/* Even though we may sometimes borrow the
 			 * contents from the work tree, we always want
 			 * one->mode.  mode is trustworthy even when
-- 
2.6.0.rc3.454.g204ad51

[PATCH 54/68] drop strcpy in favor of raw sha1_to_hex

[Jeff King]

In some cases where we strcpy() the result of sha1_to_hex(),
there's no need; the result goes directly into a printf
statement, and we can simply pass the return value from
sha1_to_hex() directly.

When this code was originally written, sha1_to_hex used a
single buffer, and it was not safe to use it twice within a
single expression. That changed as of dcb3450 (sha1_to_hex()
usage cleanup, 2006-05-03), but this code ewas never
updated.

History-dug-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Jeff King <peff@peff.net>
---
 http-push.c | 6 ++----
 walker.c    | 5 ++---
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/http-push.c b/http-push.c
index 43a9036..48f39b7 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1856,7 +1856,6 @@ int main(int argc, char **argv)
 
 	new_refs = 0;
 	for (ref = remote_refs; ref; ref = ref->next) {
-		char old_hex[60], *new_hex;
 		struct argv_array commit_argv = ARGV_ARRAY_INIT;
 
 		if (!ref->peer_ref)
@@ -1911,13 +1910,12 @@ int main(int argc, char **argv)
 		}
 		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
 		new_refs++;
-		strcpy(old_hex, sha1_to_hex(ref->old_sha1));
-		new_hex = sha1_to_hex(ref->new_sha1);
 
 		fprintf(stderr, "updating '%s'", ref->name);
 		if (strcmp(ref->name, ref->peer_ref->name))
 			fprintf(stderr, " using '%s'", ref->peer_ref->name);
-		fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
+		fprintf(stderr, "\n  from %s\n  to   %s\n",
+			sha1_to_hex(ref->old_sha1), sha1_to_hex(ref->new_sha1));
 		if (dry_run) {
 			if (helper_status)
 				printf("ok %s\n", ref->name);
diff --git a/walker.c b/walker.c
index 44a936c..cdeb63f 100644
--- a/walker.c
+++ b/walker.c
@@ -17,10 +17,9 @@ void walker_say(struct walker *walker, const char *fmt, const char *hex)
 
 static void report_missing(const struct object *obj)
 {
-	char missing_hex[41];
-	strcpy(missing_hex, sha1_to_hex(obj->sha1));
 	fprintf(stderr, "Cannot obtain needed %s %s\n",
-		obj->type ? typename(obj->type): "object", missing_hex);
+		obj->type ? typename(obj->type): "object",
+		sha1_to_hex(obj->sha1));
 	if (!is_null_sha1(current_commit_sha1))
 		fprintf(stderr, "while processing commit %s.\n",
 			sha1_to_hex(current_commit_sha1));
-- 
2.6.0.rc3.454.g204ad51

[PATCH 55/68] color: add overflow checks for parsing colors

[Jeff King]

Our color parsing is designed to never exceed COLOR_MAXLEN
bytes. But the relationship between that hand-computed
number and the parsing code is not at all obvious, and we
merely hope that it has been computed correctly for all
cases.

Let's mark the expected "end" pointer for the destination
buffer and make sure that we do not exceed it.

Signed-off-by: Jeff King <peff@peff.net>
---
 color.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/color.c b/color.c
index 9027352..22782f8 100644
--- a/color.c
+++ b/color.c
@@ -150,22 +150,24 @@ int color_parse(const char *value, char *dst)
  * already have the ANSI escape code in it. "out" should have enough
  * space in it to fit any color.
  */
-static char *color_output(char *out, const struct color *c, char type)
+static char *color_output(char *out, int len, const struct color *c, char type)
 {
 	switch (c->type) {
 	case COLOR_UNSPECIFIED:
 	case COLOR_NORMAL:
 		break;
 	case COLOR_ANSI:
+		if (len < 2)
+			die("BUG: color parsing ran out of space");
 		*out++ = type;
 		*out++ = '0' + c->value;
 		break;
 	case COLOR_256:
-		out += sprintf(out, "%c8;5;%d", type, c->value);
+		out += xsnprintf(out, len, "%c8;5;%d", type, c->value);
 		break;
 	case COLOR_RGB:
-		out += sprintf(out, "%c8;2;%d;%d;%d", type,
-			       c->red, c->green, c->blue);
+		out += xsnprintf(out, len, "%c8;2;%d;%d;%d", type,
+				 c->red, c->green, c->blue);
 		break;
 	}
 	return out;
@@ -180,12 +182,13 @@ int color_parse_mem(const char *value, int value_len, char *dst)
 {
 	const char *ptr = value;
 	int len = value_len;
+	char *end = dst + COLOR_MAXLEN;
 	unsigned int attr = 0;
 	struct color fg = { COLOR_UNSPECIFIED };
 	struct color bg = { COLOR_UNSPECIFIED };
 
 	if (!strncasecmp(value, "reset", len)) {
-		strcpy(dst, GIT_COLOR_RESET);
+		xsnprintf(dst, end - dst, GIT_COLOR_RESET);
 		return 0;
 	}
 
@@ -224,12 +227,19 @@ int color_parse_mem(const char *value, int value_len, char *dst)
 			goto bad;
 	}
 
+#undef OUT
+#define OUT(x) do { \
+	if (dst == end) \
+		die("BUG: color parsing ran out of space"); \
+	*dst++ = (x); \
+} while(0)
+
 	if (attr || !color_empty(&fg) || !color_empty(&bg)) {
 		int sep = 0;
 		int i;
 
-		*dst++ = '\033';
-		*dst++ = '[';
+		OUT('\033');
+		OUT('[');
 
 		for (i = 0; attr; i++) {
 			unsigned bit = (1 << i);
@@ -237,27 +247,28 @@ int color_parse_mem(const char *value, int value_len, char *dst)
 				continue;
 			attr &= ~bit;
 			if (sep++)
-				*dst++ = ';';
-			dst += sprintf(dst, "%d", i);
+				OUT(';');
+			dst += xsnprintf(dst, end - dst, "%d", i);
 		}
 		if (!color_empty(&fg)) {
 			if (sep++)
-				*dst++ = ';';
+				OUT(';');
 			/* foreground colors are all in the 3x range */
-			dst = color_output(dst, &fg, '3');
+			dst = color_output(dst, end - dst, &fg, '3');
 		}
 		if (!color_empty(&bg)) {
 			if (sep++)
-				*dst++ = ';';
+				OUT(';');
 			/* background colors are all in the 4x range */
-			dst = color_output(dst, &bg, '4');
+			dst = color_output(dst, end - dst, &bg, '4');
 		}
-		*dst++ = 'm';
+		OUT('m');
 	}
-	*dst = 0;
+	OUT(0);
 	return 0;
 bad:
 	return error(_("invalid color value: %.*s"), value_len, value);
+#undef OUT
 }
 
 int git_config_colorbool(const char *var, const char *value)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 56/68] use alloc_ref rather than hand-allocating "struct ref"

[Jeff King]

This saves us some manual computation, and eliminates a call
to strcpy.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fetch.c | 3 +--
 remote-curl.c   | 5 +----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 841880e..ed84963 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -639,8 +639,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 				continue;
 
 			if (rm->peer_ref) {
-				ref = xcalloc(1, sizeof(*ref) + strlen(rm->peer_ref->name) + 1);
-				strcpy(ref->name, rm->peer_ref->name);
+				ref = alloc_ref(rm->peer_ref->name);
 				hashcpy(ref->old_sha1, rm->peer_ref->old_sha1);
 				hashcpy(ref->new_sha1, rm->old_sha1);
 				ref->force = rm->peer_ref->force;
diff --git a/remote-curl.c b/remote-curl.c
index 71fbbb6..cc7a8a6 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -168,10 +168,7 @@ static struct ref *parse_info_refs(struct discovery *heads)
 				    url.buf);
 			data[i] = 0;
 			ref_name = mid + 1;
-			ref = xmalloc(sizeof(struct ref) +
-				      strlen(ref_name) + 1);
-			memset(ref, 0, sizeof(struct ref));
-			strcpy(ref->name, ref_name);
+			ref = alloc_ref(ref_name);
 			get_sha1_hex(start, ref->old_sha1);
 			if (!refs)
 				refs = ref;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 57/68] avoid sprintf and strcpy with flex arrays

[Jeff King]

When we are allocating a struct with a FLEX_ARRAY member, we
generally compute the size of the array and then sprintf or
strcpy into it. Normally we could improve a dynamic allocation
like this by using xstrfmt, but it doesn't work here; we
have to account for the size of the rest of the struct.

But we can improve things a bit by storing the length that
we use for the allocation, and then feeding it to xsnprintf
or memcpy, which makes it more obvious that we are not
writing more than the allocated number of bytes.

It would be nice if we had some kind of helper for
allocating generic flex arrays, but it doesn't work that
well:

 - the call signature is a little bit unwieldy:

      d = flex_struct(sizeof(*d), offsetof(d, path), fmt, ...);

   You need offsetof here instead of just writing to the
   end of the base size, because we don't know how the
   struct is packed (partially this is because FLEX_ARRAY
   might not be zero, though we can account for that; but
   the size of the struct may actually be rounded up for
   alignment, and we can't know that).

 - some sites do clever things, like over-allocating because
   they know they will write larger things into the buffer
   later (e.g., struct packed_git here).

So we're better off to just write out each allocation (or
add type-specific helpers, though many of these are one-off
allocations anyway).

Signed-off-by: Jeff King <peff@peff.net>
---
 archive.c       | 5 +++--
 builtin/blame.c | 5 +++--
 fast-import.c   | 6 ++++--
 refs.c          | 8 ++++----
 sha1_file.c     | 5 +++--
 submodule.c     | 6 ++++--
 6 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/archive.c b/archive.c
index 01b0899..4ac86c8 100644
--- a/archive.c
+++ b/archive.c
@@ -171,13 +171,14 @@ static void queue_directory(const unsigned char *sha1,
 		unsigned mode, int stage, struct archiver_context *c)
 {
 	struct directory *d;
-	d = xmallocz(sizeof(*d) + base->len + 1 + strlen(filename));
+	size_t len = base->len + 1 + strlen(filename) + 1;
+	d = xmalloc(sizeof(*d) + len);
 	d->up	   = c->bottom;
 	d->baselen = base->len;
 	d->mode	   = mode;
 	d->stage   = stage;
 	c->bottom  = d;
-	d->len = sprintf(d->path, "%.*s%s/", (int)base->len, base->buf, filename);
+	d->len = xsnprintf(d->path, len, "%.*s%s/", (int)base->len, base->buf, filename);
 	hashcpy(d->oid.hash, sha1);
 }
 
diff --git a/builtin/blame.c b/builtin/blame.c
index e253ac0..e70fb6d 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -459,12 +459,13 @@ static void queue_blames(struct scoreboard *sb, struct origin *porigin,
 static struct origin *make_origin(struct commit *commit, const char *path)
 {
 	struct origin *o;
-	o = xcalloc(1, sizeof(*o) + strlen(path) + 1);
+	size_t pathlen = strlen(path) + 1;
+	o = xcalloc(1, sizeof(*o) + pathlen);
 	o->commit = commit;
 	o->refcnt = 1;
 	o->next = commit->util;
 	commit->util = o;
-	strcpy(o->path, path);
+	memcpy(o->path, path, pathlen); /* includes NUL */
 	return o;
 }
 
diff --git a/fast-import.c b/fast-import.c
index d0c2502..895c6b4 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -863,13 +863,15 @@ static void start_packfile(void)
 {
 	static char tmp_file[PATH_MAX];
 	struct packed_git *p;
+	int namelen;
 	struct pack_header hdr;
 	int pack_fd;
 
 	pack_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
 			      "pack/tmp_pack_XXXXXX");
-	p = xcalloc(1, sizeof(*p) + strlen(tmp_file) + 2);
-	strcpy(p->pack_name, tmp_file);
+	namelen = strlen(tmp_file) + 2;
+	p = xcalloc(1, sizeof(*p) + namelen);
+	xsnprintf(p->pack_name, namelen, "%s", tmp_file);
 	p->pack_fd = pack_fd;
 	p->do_not_close = 1;
 	pack_file = sha1fd(pack_fd, p->pack_name);
diff --git a/refs.c b/refs.c
index c2709de..9937a40 100644
--- a/refs.c
+++ b/refs.c
@@ -2695,7 +2695,7 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
 		int namelen = strlen(entry->name) + 1;
 		struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
 		hashcpy(n->sha1, entry->u.value.oid.hash);
-		strcpy(n->name, entry->name);
+		memcpy(n->name, entry->name, namelen); /* includes NUL */
 		n->next = cb->ref_to_prune;
 		cb->ref_to_prune = n;
 	}
@@ -3984,10 +3984,10 @@ void ref_transaction_free(struct ref_transaction *transaction)
 static struct ref_update *add_update(struct ref_transaction *transaction,
 				     const char *refname)
 {
-	size_t len = strlen(refname);
-	struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
+	size_t len = strlen(refname) + 1;
+	struct ref_update *update = xcalloc(1, sizeof(*update) + len);
 
-	strcpy((char *)update->refname, refname);
+	memcpy((char *)update->refname, refname, len); /* includes NUL */
 	ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 	transaction->updates[transaction->nr++] = update;
 	return update;
diff --git a/sha1_file.c b/sha1_file.c
index 4211af1..cc3de24 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1180,9 +1180,10 @@ struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 {
 	const char *path = sha1_pack_name(sha1);
-	struct packed_git *p = alloc_packed_git(strlen(path) + 1);
+	int alloc = strlen(path) + 1;
+	struct packed_git *p = alloc_packed_git(alloc);
 
-	strcpy(p->pack_name, path);
+	memcpy(p->pack_name, path, alloc); /* includes NUL */
 	hashcpy(p->sha1, sha1);
 	if (check_packed_git_idx(idx_path, p)) {
 		free(p);
diff --git a/submodule.c b/submodule.c
index 245ed4d..c480ed5 100644
--- a/submodule.c
+++ b/submodule.c
@@ -122,6 +122,7 @@ static int add_submodule_odb(const char *path)
 	struct strbuf objects_directory = STRBUF_INIT;
 	struct alternate_object_database *alt_odb;
 	int ret = 0;
+	int alloc;
 	const char *git_dir;
 
 	strbuf_addf(&objects_directory, "%s/.git", path);
@@ -142,9 +143,10 @@ static int add_submodule_odb(const char *path)
 					objects_directory.len))
 			goto done;
 
-	alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
+	alloc = objects_directory.len + 42; /* for "12/345..." sha1 */
+	alt_odb = xmalloc(sizeof(*alt_odb) + alloc);
 	alt_odb->next = alt_odb_list;
-	strcpy(alt_odb->base, objects_directory.buf);
+	xsnprintf(alt_odb->base, alloc, "%s", objects_directory.buf);
 	alt_odb->name = alt_odb->base + objects_directory.len;
 	alt_odb->name[2] = '/';
 	alt_odb->name[40] = '\0';
-- 
2.6.0.rc3.454.g204ad51

[PATCH 58/68] receive-pack: simplify keep_arg computation

[Jeff King]

To generate "--keep=receive-pack $pid on $host", we write
progressively into a single buffer, which requires keeping
track of how much we've written so far. But since the result
is destined to go into our argv array, we can simply use
argv_array_pushf.

Unfortunately we still have to have a fixed-size buffer for
the gethostname() call, but at least it now doesn't involve
any extra size computation. And as a bonus, we drop an
sprintf and a strcpy call.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/receive-pack.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 39eb064..bcb624b 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1524,15 +1524,18 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 		if (status)
 			return "unpack-objects abnormal exit";
 	} else {
-		int s;
-		char keep_arg[256];
-
-		s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
-		if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
-			strcpy(keep_arg + s, "localhost");
+		char hostname[256];
 
 		argv_array_pushl(&child.args, "index-pack",
-				 "--stdin", hdr_arg, keep_arg, NULL);
+				 "--stdin", hdr_arg, NULL);
+
+		if (gethostname(hostname, sizeof(hostname)))
+			xsnprintf(hostname, sizeof(hostname), "localhost");
+		argv_array_pushf(&child.args,
+				 "--keep=receive-pack %"PRIuMAX" on %s",
+				 (uintmax_t)getpid(),
+				 hostname);
+
 		if (fsck_objects)
 			argv_array_pushf(&child.args, "--strict%s",
 				fsck_msg_types.buf);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 59/68] help: clean up kfmclient munging

[Jeff King]

When we are going to launch "/path/to/konqueror", we instead
rewrite this into "/path/to/kfmclient" by duplicating the
original string and writing over the ending bits. This can
be done more obviously with strip_suffix and xstrfmt.

Note that we also fix a subtle bug with the "filename"
parameter, which is passed as argv[0] to the child. If the
user has configured a program name with no directory
component, we always pass the string "kfmclient", even if
your program is called something else. But if you give a
full path, we give the basename of that path. But more
bizarrely, if we rewrite "konqueror" to "kfmclient", we
still pass "konqueror".

The history of this function doesn't reveal anything
interesting, so it looks like just an oversight from
combining the suffix-munging with the basename-finding.
Let's just call basename on the munged path, which produces
consistent results (if you gave a program, whether a full
path or not, we pass its basename).

Probably this doesn't matter at all in practice, but it
makes the code slightly less confusing to read.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/help.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/builtin/help.c b/builtin/help.c
index fba8c01..e1650ab 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -140,17 +140,10 @@ static void exec_man_konqueror(const char *path, const char *page)
 
 		/* It's simpler to launch konqueror using kfmclient. */
 		if (path) {
-			const char *file = strrchr(path, '/');
-			if (file && !strcmp(file + 1, "konqueror")) {
-				char *new = xstrdup(path);
-				char *dest = strrchr(new, '/');
-
-				/* strlen("konqueror") == strlen("kfmclient") */
-				strcpy(dest + 1, "kfmclient");
-				path = new;
-			}
-			if (file)
-				filename = file;
+			size_t len;
+			if (strip_suffix(path, "/konqueror", &len))
+				path = xstrfmt("%.*s/kfmclient", (int)len, path);
+			filename = basename((char *)path);
 		} else
 			path = "kfmclient";
 		strbuf_addf(&man_page, "man:%s(1)", page);
-- 
2.6.0.rc3.454.g204ad51

[PATCH 60/68] prefer memcpy to strcpy

[Jeff King]

When we already know the length of a string (e.g., because
we just malloc'd to fit it), it's nicer to use memcpy than
strcpy, as it makes it more obvious that we are not going to
overflow the buffer (because the size we pass matches the
size in the allocation).

This also eliminates calls to strcpy, which make auditing
the code base harder.

Signed-off-by: Jeff King <peff@peff.net>
---
 compat/nedmalloc/nedmalloc.c | 5 +++--
 fast-import.c                | 5 +++--
 revision.c                   | 2 +-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
index 609ebba..a0a16eb 100644
--- a/compat/nedmalloc/nedmalloc.c
+++ b/compat/nedmalloc/nedmalloc.c
@@ -957,8 +957,9 @@ char *strdup(const char *s1)
 {
 	char *s2 = 0;
 	if (s1) {
-		s2 = malloc(strlen(s1) + 1);
-		strcpy(s2, s1);
+		size_t len = strlen(s1) + 1;
+		s2 = malloc(len);
+		memcpy(s2, s1, len);
 	}
 	return s2;
 }
diff --git a/fast-import.c b/fast-import.c
index 895c6b4..cf6d8bc 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -644,8 +644,9 @@ static void *pool_calloc(size_t count, size_t size)
 
 static char *pool_strdup(const char *s)
 {
-	char *r = pool_alloc(strlen(s) + 1);
-	strcpy(r, s);
+	size_t len = strlen(s) + 1;
+	char *r = pool_alloc(len);
+	memcpy(r, s, len);
 	return r;
 }
 
diff --git a/revision.c b/revision.c
index af2a18e..2236463 100644
--- a/revision.c
+++ b/revision.c
@@ -38,7 +38,7 @@ char *path_name(const struct name_path *path, const char *name)
 	}
 	n = xmalloc(len);
 	m = n + len - (nlen + 1);
-	strcpy(m, name);
+	memcpy(m, name, nlen + 1);
 	for (p = path; p; p = p->up) {
 		if (p->elem_len) {
 			m -= p->elem_len + 1;
-- 
2.6.0.rc3.454.g204ad51

[PATCH 61/68] color: add color_set helper for copying raw colors

[Jeff King]

To set up default colors, we sometimes strcpy() from the
default string literals into our color buffers. This isn't a
bug (assuming the destination is COLOR_MAXLEN bytes), but
makes it harder to audit the code for problematic strcpy
calls.

Let's introduce a color_set which copies under the
assumption that there are COLOR_MAXLEN bytes in the
destination (of course you can call it on a smaller buffer,
so this isn't providing a huge amount of safety, but it's
more convenient than calling xsnprintf yourself).

Signed-off-by: Jeff King <peff@peff.net>
---
 color.c |  5 +++++
 color.h |  7 +++++++
 grep.c  | 32 ++++++++++++++++----------------
 3 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/color.c b/color.c
index 22782f8..8f85153 100644
--- a/color.c
+++ b/color.c
@@ -145,6 +145,11 @@ int color_parse(const char *value, char *dst)
 	return color_parse_mem(value, strlen(value), dst);
 }
 
+void color_set(char *dst, const char *color_bytes)
+{
+	xsnprintf(dst, COLOR_MAXLEN, "%s", color_bytes);
+}
+
 /*
  * Write the ANSI color codes for "c" to "out"; the string should
  * already have the ANSI escape code in it. "out" should have enough
diff --git a/color.h b/color.h
index 7fe77fb..e155d13 100644
--- a/color.h
+++ b/color.h
@@ -75,6 +75,13 @@ extern int color_stdout_is_tty;
 int git_color_config(const char *var, const char *value, void *cb);
 int git_color_default_config(const char *var, const char *value, void *cb);
 
+/*
+ * Set the color buffer (which must be COLOR_MAXLEN bytes)
+ * to the raw color bytes; this is useful for initializing
+ * default color variables.
+ */
+void color_set(char *dst, const char *color_bytes);
+
 int git_config_colorbool(const char *var, const char *value);
 int want_color(int var);
 int color_parse(const char *value, char *dst);
diff --git a/grep.c b/grep.c
index 6c68d5b..7b2b96a 100644
--- a/grep.c
+++ b/grep.c
@@ -31,14 +31,14 @@ void init_grep_defaults(void)
 	opt->max_depth = -1;
 	opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
 	opt->extended_regexp_option = 0;
-	strcpy(opt->color_context, "");
-	strcpy(opt->color_filename, "");
-	strcpy(opt->color_function, "");
-	strcpy(opt->color_lineno, "");
-	strcpy(opt->color_match_context, GIT_COLOR_BOLD_RED);
-	strcpy(opt->color_match_selected, GIT_COLOR_BOLD_RED);
-	strcpy(opt->color_selected, "");
-	strcpy(opt->color_sep, GIT_COLOR_CYAN);
+	color_set(opt->color_context, "");
+	color_set(opt->color_filename, "");
+	color_set(opt->color_function, "");
+	color_set(opt->color_lineno, "");
+	color_set(opt->color_match_context, GIT_COLOR_BOLD_RED);
+	color_set(opt->color_match_selected, GIT_COLOR_BOLD_RED);
+	color_set(opt->color_selected, "");
+	color_set(opt->color_sep, GIT_COLOR_CYAN);
 	opt->color = -1;
 }
 
@@ -151,14 +151,14 @@ void grep_init(struct grep_opt *opt, const char *prefix)
 	opt->regflags = def->regflags;
 	opt->relative = def->relative;
 
-	strcpy(opt->color_context, def->color_context);
-	strcpy(opt->color_filename, def->color_filename);
-	strcpy(opt->color_function, def->color_function);
-	strcpy(opt->color_lineno, def->color_lineno);
-	strcpy(opt->color_match_context, def->color_match_context);
-	strcpy(opt->color_match_selected, def->color_match_selected);
-	strcpy(opt->color_selected, def->color_selected);
-	strcpy(opt->color_sep, def->color_sep);
+	color_set(opt->color_context, def->color_context);
+	color_set(opt->color_filename, def->color_filename);
+	color_set(opt->color_function, def->color_function);
+	color_set(opt->color_lineno, def->color_lineno);
+	color_set(opt->color_match_context, def->color_match_context);
+	color_set(opt->color_match_selected, def->color_match_selected);
+	color_set(opt->color_selected, def->color_selected);
+	color_set(opt->color_sep, def->color_sep);
 }
 
 void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 62/68] notes: document length of fanout path with a constant

[Jeff King]

We know that a fanned-out sha1 in a notes tree cannot be
more than "aa/bb/cc/...", and we have an assert() to confirm
that. But let's factor out that length into a constant so we
can be sure it is used consistently. And even though we
assert() earlier, let's replace a strcpy with xsnprintf, so
it is clear to a reader that all cases are covered.

Signed-off-by: Jeff King <peff@peff.net>
---
 notes.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/notes.c b/notes.c
index eacd2a6..db77922 100644
--- a/notes.c
+++ b/notes.c
@@ -539,6 +539,9 @@ static unsigned char determine_fanout(struct int_node *tree, unsigned char n,
 	return fanout + 1;
 }
 
+/* hex SHA1 + 19 * '/' + NUL */
+#define FANOUT_PATH_MAX 40 + 19 + 1
+
 static void construct_path_with_fanout(const unsigned char *sha1,
 		unsigned char fanout, char *path)
 {
@@ -551,7 +554,7 @@ static void construct_path_with_fanout(const unsigned char *sha1,
 		path[i++] = '/';
 		fanout--;
 	}
-	strcpy(path + i, hex_sha1 + j);
+	xsnprintf(path + i, FANOUT_PATH_MAX - i, "%s", hex_sha1 + j);
 }
 
 static int for_each_note_helper(struct notes_tree *t, struct int_node *tree,
@@ -562,7 +565,7 @@ static int for_each_note_helper(struct notes_tree *t, struct int_node *tree,
 	void *p;
 	int ret = 0;
 	struct leaf_node *l;
-	static char path[40 + 19 + 1];  /* hex SHA1 + 19 * '/' + NUL */
+	static char path[FANOUT_PATH_MAX];
 
 	fanout = determine_fanout(tree, n, fanout);
 	for (i = 0; i < 16; i++) {
@@ -595,7 +598,7 @@ redo:
 				/* invoke callback with subtree */
 				unsigned int path_len =
 					l->key_sha1[19] * 2 + fanout;
-				assert(path_len < 40 + 19);
+				assert(path_len < FANOUT_PATH_MAX - 1);
 				construct_path_with_fanout(l->key_sha1, fanout,
 							   path);
 				/* Create trailing slash, if needed */
-- 
2.6.0.rc3.454.g204ad51

[PATCH 63/68] convert strncpy to memcpy

[Jeff King]

strncpy is known to be a confusing function because of its
termination semantics.  These calls are all correct, but it
takes some examination to see why. In particular, every one
of them expects to copy up to the length limit, and then
makes some arrangement for terminating the result.

We can just use memcpy, along with noting explicitly how the
result is terminated (if it is not already obvious). That
should make it more clear to a reader that we are doing the
right thing.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/help.c | 4 ++--
 fast-import.c  | 2 +-
 tag.c          | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/builtin/help.c b/builtin/help.c
index e1650ab..1cd0c1e 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -176,7 +176,7 @@ static void add_man_viewer(const char *name)
 	while (*p)
 		p = &((*p)->next);
 	*p = xcalloc(1, (sizeof(**p) + len + 1));
-	strncpy((*p)->name, name, len);
+	memcpy((*p)->name, name, len); /* NUL-terminated by xcalloc */
 }
 
 static int supported_man_viewer(const char *name, size_t len)
@@ -192,7 +192,7 @@ static void do_add_man_viewer_info(const char *name,
 {
 	struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 
-	strncpy(new->name, name, len);
+	memcpy(new->name, name, len); /* NUL-terminated by xcalloc */
 	new->info = xstrdup(value);
 	new->next = man_viewer_info_list;
 	man_viewer_info_list = new;
diff --git a/fast-import.c b/fast-import.c
index cf6d8bc..4d01efc 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -703,7 +703,7 @@ static struct atom_str *to_atom(const char *s, unsigned short len)
 
 	c = pool_alloc(sizeof(struct atom_str) + len + 1);
 	c->str_len = len;
-	strncpy(c->str_dat, s, len);
+	memcpy(c->str_dat, s, len);
 	c->str_dat[len] = 0;
 	c->next_atom = atom_table[hc];
 	atom_table[hc] = c;
diff --git a/tag.c b/tag.c
index 5b0ac62..5b2a06d 100644
--- a/tag.c
+++ b/tag.c
@@ -82,7 +82,7 @@ int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
 	nl = memchr(bufptr, '\n', tail - bufptr);
 	if (!nl || sizeof(type) <= (nl - bufptr))
 		return -1;
-	strncpy(type, bufptr, nl - bufptr);
+	memcpy(type, bufptr, nl - bufptr);
 	type[nl - bufptr] = '\0';
 	bufptr = nl + 1;
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 64/68] fsck: drop inode-sorting code

[Jeff King]

Fsck tries to access loose objects in order of inode number,
with the hope that this would make cold cache access faster
on a spinning disk. This dates back to 7e8c174 (fsck-cache:
sort entries by inode number, 2005-05-02), which predates
the invention of packfiles.

These days, there's not much point in trying to optimize
cold cache for a large number of loose objects. You are much
better off to simply pack the objects, which will reduce the
disk footprint _and_ provide better locality of data access.

So while you can certainly construct pathological cases
where this code might help, it is not worth the trouble
anymore.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fsck.c | 70 ++--------------------------------------------------------
 1 file changed, 2 insertions(+), 68 deletions(-)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index a019f4a..73c3596 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -39,14 +39,6 @@ static int show_dangling = 1;
 #define ERROR_REACHABLE 02
 #define ERROR_PACK 04
 
-#ifdef NO_D_INO_IN_DIRENT
-#define SORT_DIRENT 0
-#define DIRENT_SORT_HINT(de) 0
-#else
-#define SORT_DIRENT 1
-#define DIRENT_SORT_HINT(de) ((de)->d_ino)
-#endif
-
 static int fsck_config(const char *var, const char *value, void *cb)
 {
 	if (strcmp(var, "fsck.skiplist") == 0) {
@@ -373,64 +365,6 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 	return fsck_obj(obj);
 }
 
-/*
- * This is the sorting chunk size: make it reasonably
- * big so that we can sort well..
- */
-#define MAX_SHA1_ENTRIES (1024)
-
-struct sha1_entry {
-	unsigned long ino;
-	unsigned char sha1[20];
-};
-
-static struct {
-	unsigned long nr;
-	struct sha1_entry *entry[MAX_SHA1_ENTRIES];
-} sha1_list;
-
-static int ino_compare(const void *_a, const void *_b)
-{
-	const struct sha1_entry *a = _a, *b = _b;
-	unsigned long ino1 = a->ino, ino2 = b->ino;
-	return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
-}
-
-static void fsck_sha1_list(void)
-{
-	int i, nr = sha1_list.nr;
-
-	if (SORT_DIRENT)
-		qsort(sha1_list.entry, nr,
-		      sizeof(struct sha1_entry *), ino_compare);
-	for (i = 0; i < nr; i++) {
-		struct sha1_entry *entry = sha1_list.entry[i];
-		unsigned char *sha1 = entry->sha1;
-
-		sha1_list.entry[i] = NULL;
-		if (fsck_sha1(sha1))
-			errors_found |= ERROR_OBJECT;
-		free(entry);
-	}
-	sha1_list.nr = 0;
-}
-
-static void add_sha1_list(unsigned char *sha1, unsigned long ino)
-{
-	struct sha1_entry *entry = xmalloc(sizeof(*entry));
-	int nr;
-
-	entry->ino = ino;
-	hashcpy(entry->sha1, sha1);
-	nr = sha1_list.nr;
-	if (nr == MAX_SHA1_ENTRIES) {
-		fsck_sha1_list();
-		nr = 0;
-	}
-	sha1_list.entry[nr] = entry;
-	sha1_list.nr = ++nr;
-}
-
 static inline int is_loose_object_file(struct dirent *de,
 				       char *name, unsigned char *sha1)
 {
@@ -459,7 +393,8 @@ static void fsck_dir(int i, char *path)
 		if (is_dot_or_dotdot(de->d_name))
 			continue;
 		if (is_loose_object_file(de, name, sha1)) {
-			add_sha1_list(sha1, DIRENT_SORT_HINT(de));
+			if (fsck_sha1(sha1))
+				errors_found |= ERROR_OBJECT;
 			continue;
 		}
 		if (starts_with(de->d_name, "tmp_obj_"))
@@ -573,7 +508,6 @@ static void fsck_object_dir(const char *path)
 		display_progress(progress, i+1);
 	}
 	stop_progress(&progress);
-	fsck_sha1_list();
 }
 
 static int fsck_head_link(void)
-- 
2.6.0.rc3.454.g204ad51

[PATCH 65/68] Makefile: drop D_INO_IN_DIRENT build knob

[Jeff King]

Now that fsck has dropped its inode-sorting, there are no
longer any users of this knob, and it can go away.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile         | 5 -----
 config.mak.uname | 3 ---
 configure.ac     | 7 -------
 3 files changed, 15 deletions(-)

diff --git a/Makefile b/Makefile
index 8d5df7e..2f350ca 100644
--- a/Makefile
+++ b/Makefile
@@ -74,8 +74,6 @@ all::
 # Define HAVE_PATHS_H if you have paths.h and want to use the default PATH
 # it specifies.
 #
-# Define NO_D_INO_IN_DIRENT if you don't have d_ino in your struct dirent.
-#
 # Define NO_D_TYPE_IN_DIRENT if your platform defines DT_UNKNOWN but lacks
 # d_type in struct dirent (Cygwin 1.5, fixed in Cygwin 1.7).
 #
@@ -1160,9 +1158,6 @@ endif
 ifdef NO_D_TYPE_IN_DIRENT
 	BASIC_CFLAGS += -DNO_D_TYPE_IN_DIRENT
 endif
-ifdef NO_D_INO_IN_DIRENT
-	BASIC_CFLAGS += -DNO_D_INO_IN_DIRENT
-endif
 ifdef NO_GECOS_IN_PWENT
 	BASIC_CFLAGS += -DNO_GECOS_IN_PWENT
 endif
diff --git a/config.mak.uname b/config.mak.uname
index 943c439..f34dcaa 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -166,7 +166,6 @@ endif
 ifeq ($(uname_O),Cygwin)
 	ifeq ($(shell expr "$(uname_R)" : '1\.[1-6]\.'),4)
 		NO_D_TYPE_IN_DIRENT = YesPlease
-		NO_D_INO_IN_DIRENT = YesPlease
 		NO_STRCASESTR = YesPlease
 		NO_MEMMEM = YesPlease
 		NO_MKSTEMPS = YesPlease
@@ -370,7 +369,6 @@ ifeq ($(uname_S),Windows)
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	NATIVE_CRLF = YesPlease
 	DEFAULT_HELP_FORMAT = html
-	NO_D_INO_IN_DIRENT = YesPlease
 
 	CC = compat/vcbuild/scripts/clink.pl
 	AR = compat/vcbuild/scripts/lib.pl
@@ -520,7 +518,6 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_INET_NTOP = YesPlease
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	DEFAULT_HELP_FORMAT = html
-	NO_D_INO_IN_DIRENT = YesPlease
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -D_USE_32BIT_TIME_T -DNOGDI -Icompat -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
 	COMPAT_OBJS += compat/mingw.o compat/winansi.o \
diff --git a/configure.ac b/configure.ac
index 14012fa..3fcca61 100644
--- a/configure.ac
+++ b/configure.ac
@@ -767,13 +767,6 @@ elif test x$ac_cv_member_struct_stat_st_mtim_tv_nsec != xyes; then
 	GIT_CONF_SUBST([NO_NSEC])
 fi
 #
-# Define NO_D_INO_IN_DIRENT if you don't have d_ino in your struct dirent.
-AC_CHECK_MEMBER(struct dirent.d_ino,
-[NO_D_INO_IN_DIRENT=],
-[NO_D_INO_IN_DIRENT=YesPlease],
-[#include <dirent.h>])
-GIT_CONF_SUBST([NO_D_INO_IN_DIRENT])
-#
 # Define NO_D_TYPE_IN_DIRENT if your platform defines DT_UNKNOWN but lacks
 # d_type in struct dirent (latest Cygwin -- will be fixed soonish).
 AC_CHECK_MEMBER(struct dirent.d_type,
-- 
2.6.0.rc3.454.g204ad51

[PATCH 66/68] fsck: use for_each_loose_file_in_objdir

[Jeff King]

Since 27e1e22 (prune: factor out loose-object directory
traversal, 2014-10-15), we now have a generic callback
system for iterating over the loose object directories. This
is used by prune, count-objects, etc.

We did not convert git-fsck at the time because it
implemented an inode-sorting scheme that was not part of the
generic code. Now that the inode-sorting code is gone, we
can reuse the generic code.  The result is shorter,
hopefully more readable, and drops some unchecked sprintf
calls.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fsck.c | 69 ++++++++++++++++++++--------------------------------------
 1 file changed, 23 insertions(+), 46 deletions(-)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 73c3596..2fe6a31 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -365,45 +365,6 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 	return fsck_obj(obj);
 }
 
-static inline int is_loose_object_file(struct dirent *de,
-				       char *name, unsigned char *sha1)
-{
-	if (strlen(de->d_name) != 38)
-		return 0;
-	memcpy(name + 2, de->d_name, 39);
-	return !get_sha1_hex(name, sha1);
-}
-
-static void fsck_dir(int i, char *path)
-{
-	DIR *dir = opendir(path);
-	struct dirent *de;
-	char name[100];
-
-	if (!dir)
-		return;
-
-	if (verbose)
-		fprintf(stderr, "Checking directory %s\n", path);
-
-	sprintf(name, "%02x", i);
-	while ((de = readdir(dir)) != NULL) {
-		unsigned char sha1[20];
-
-		if (is_dot_or_dotdot(de->d_name))
-			continue;
-		if (is_loose_object_file(de, name, sha1)) {
-			if (fsck_sha1(sha1))
-				errors_found |= ERROR_OBJECT;
-			continue;
-		}
-		if (starts_with(de->d_name, "tmp_obj_"))
-			continue;
-		fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
-	}
-	closedir(dir);
-}
-
 static int default_refs;
 
 static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1)
@@ -491,9 +452,28 @@ static void get_default_heads(void)
 	}
 }
 
+static int fsck_loose(const unsigned char *sha1, const char *path, void *data)
+{
+	if (fsck_sha1(sha1))
+		errors_found |= ERROR_OBJECT;
+	return 0;
+}
+
+static int fsck_cruft(const char *basename, const char *path, void *data)
+{
+	if (!starts_with(basename, "tmp_obj_"))
+		fprintf(stderr, "bad sha1 file: %s\n", path);
+	return 0;
+}
+
+static int fsck_subdir(int nr, const char *path, void *progress)
+{
+	display_progress(progress, nr + 1);
+	return 0;
+}
+
 static void fsck_object_dir(const char *path)
 {
-	int i;
 	struct progress *progress = NULL;
 
 	if (verbose)
@@ -501,12 +481,9 @@ static void fsck_object_dir(const char *path)
 
 	if (show_progress)
 		progress = start_progress(_("Checking object directories"), 256);
-	for (i = 0; i < 256; i++) {
-		static char dir[4096];
-		sprintf(dir, "%s/%02x", path, i);
-		fsck_dir(i, dir);
-		display_progress(progress, i+1);
-	}
+
+	for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
+				      progress);
 	stop_progress(&progress);
 }
 
-- 
2.6.0.rc3.454.g204ad51

[PATCH 67/68] use strbuf_complete to conditionally append slash

[Jeff King]

When working with paths in strbufs, we frequently want to
ensure that a directory contains a trailing slash before
appending to it. We can shorten this code (and make the
intent more obvious) by calling strbuf_complete.

Most of these cases are trivially identical conversions, but
there are two things to note:

  - in a few cases we did not check that the strbuf is
    non-empty (which would lead to an out-of-bounds memory
    access). These were generally not triggerable in
    practice, either from earlier assertions, or typically
    because we would have just fed the strbuf to opendir(),
    which would choke on an empty path.

  - in a few cases we indexed the buffer with "original_len"
    or similar, rather than the current sb->len, and it is
    not immediately obvious from the diff that they are the
    same. In all of these cases, I manually verified that
    the strbuf does not change between the assignment and
    the strbuf_complete call.

This does not convert cases which look like:

  if (sb->len && !is_dir_sep(sb->buf[sb->len - 1]))
	  strbuf_addch(sb, '/');

as those are obviously semantically different. Some of these
cases arguably should be doing that, but that is out of
scope for this change, which aims purely for cleanup with no
behavior change (and at least it will make such sites easier
to find and examine in the future, as we can grep for
strbuf_complete).

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/clean.c | 6 ++----
 builtin/log.c   | 3 +--
 diff-no-index.c | 6 ++----
 dir.c           | 6 ++----
 path.c          | 3 +--
 refs.c          | 3 +--
 url.c           | 3 +--
 7 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/builtin/clean.c b/builtin/clean.c
index df53def..d7acb94 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -159,8 +159,7 @@ static int is_git_repository(struct strbuf *path)
 	int gitfile_error;
 	size_t orig_path_len = path->len;
 	assert(orig_path_len != 0);
-	if (path->buf[orig_path_len - 1] != '/')
-		strbuf_addch(path, '/');
+	strbuf_complete(path, '/');
 	strbuf_addstr(path, ".git");
 	if (read_gitfile_gently(path->buf, &gitfile_error) || is_git_directory(path->buf))
 		ret = 1;
@@ -206,8 +205,7 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 		return res;
 	}
 
-	if (path->buf[original_len - 1] != '/')
-		strbuf_addch(path, '/');
+	strbuf_complete(path, '/');
 
 	len = path->len;
 	while ((e = readdir(dir)) != NULL) {
diff --git a/builtin/log.c b/builtin/log.c
index a491d3d..dda671d 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -796,8 +796,7 @@ static int reopen_stdout(struct commit *commit, const char *subject,
 		if (filename.len >=
 		    PATH_MAX - FORMAT_PATCH_NAME_MAX - suffix_len)
 			return error(_("name of output directory is too long"));
-		if (filename.buf[filename.len - 1] != '/')
-			strbuf_addch(&filename, '/');
+		strbuf_complete(&filename, '/');
 	}
 
 	if (rev->numbered_files)
diff --git a/diff-no-index.c b/diff-no-index.c
index 0320605..8e0fd27 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -136,15 +136,13 @@ static int queue_diff(struct diff_options *o,
 
 		if (name1) {
 			strbuf_addstr(&buffer1, name1);
-			if (buffer1.len && buffer1.buf[buffer1.len - 1] != '/')
-				strbuf_addch(&buffer1, '/');
+			strbuf_complete(&buffer1, '/');
 			len1 = buffer1.len;
 		}
 
 		if (name2) {
 			strbuf_addstr(&buffer2, name2);
-			if (buffer2.len && buffer2.buf[buffer2.len - 1] != '/')
-				strbuf_addch(&buffer2, '/');
+			strbuf_complete(&buffer2, '/');
 			len2 = buffer2.len;
 		}
 
diff --git a/dir.c b/dir.c
index 7b25634..79fdad8 100644
--- a/dir.c
+++ b/dir.c
@@ -1519,8 +1519,7 @@ static enum path_treatment treat_path_fast(struct dir_struct *dir,
 	}
 	strbuf_addstr(path, cdir->ucd->name);
 	/* treat_one_path() does this before it calls treat_directory() */
-	if (path->buf[path->len - 1] != '/')
-		strbuf_addch(path, '/');
+	strbuf_complete(path, '/');
 	if (cdir->ucd->check_only)
 		/*
 		 * check_only is set as a result of treat_directory() getting
@@ -2126,8 +2125,7 @@ static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
 		else
 			return -1;
 	}
-	if (path->buf[original_len - 1] != '/')
-		strbuf_addch(path, '/');
+	strbuf_complete(path, '/');
 
 	len = path->len;
 	while ((e = readdir(dir)) != NULL) {
diff --git a/path.c b/path.c
index c597473..c105a9e 100644
--- a/path.c
+++ b/path.c
@@ -240,8 +240,7 @@ static void do_submodule_path(struct strbuf *buf, const char *path,
 	const char *git_dir;
 
 	strbuf_addstr(buf, path);
-	if (buf->len && buf->buf[buf->len - 1] != '/')
-		strbuf_addch(buf, '/');
+	strbuf_complete(buf, '/');
 	strbuf_addstr(buf, ".git");
 
 	git_dir = read_gitfile(buf->buf);
diff --git a/refs.c b/refs.c
index 9937a40..b2a9229 100644
--- a/refs.c
+++ b/refs.c
@@ -2193,8 +2193,7 @@ int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 
 	if (!has_glob_specials(pattern)) {
 		/* Append implied '/' '*' if not present. */
-		if (real_pattern.buf[real_pattern.len - 1] != '/')
-			strbuf_addch(&real_pattern, '/');
+		strbuf_complete(&real_pattern, '/');
 		/* No need to check for '*', there is none. */
 		strbuf_addch(&real_pattern, '*');
 	}
diff --git a/url.c b/url.c
index 7ca2a69..2d89ad1 100644
--- a/url.c
+++ b/url.c
@@ -120,8 +120,7 @@ char *url_decode_parameter_value(const char **query)
 void end_url_with_slash(struct strbuf *buf, const char *url)
 {
 	strbuf_addstr(buf, url);
-	if (buf->len && buf->buf[buf->len - 1] != '/')
-		strbuf_addch(buf, '/');
+	strbuf_complete(buf, '/');
 }
 
 void str_end_url_with_slash(const char *url, char **dest) {
-- 
2.6.0.rc3.454.g204ad51

[PATCH 68/68] name-rev: use strip_suffix to avoid magic numbers

[Jeff King]

The manual size computations here are correct, but using
strip_suffix makes that obvious, and hopefully communicates
the intent of the code more clearly.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/name-rev.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 8a3a0cd..0377fc1 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -55,16 +55,15 @@ copy_data:
 			parents;
 			parents = parents->next, parent_number++) {
 		if (parent_number > 1) {
-			int len = strlen(tip_name);
+			size_t len;
 			char *new_name;
 
-			if (len > 2 && !strcmp(tip_name + len - 2, "^0"))
-				len -= 2;
+			strip_suffix(tip_name, "^0", &len);
 			if (generation > 0)
-				new_name = xstrfmt("%.*s~%d^%d", len, tip_name,
+				new_name = xstrfmt("%.*s~%d^%d", (int)len, tip_name,
 						   generation, parent_number);
 			else
-				new_name = xstrfmt("%.*s^%d", len, tip_name,
+				new_name = xstrfmt("%.*s^%d", (int)len, tip_name,
 						   parent_number);
 
 			name_rev(parents->item, new_name, 0,
-- 
2.6.0.rc3.454.g204ad51

Re: [PATCH 54/68] drop strcpy in favor of raw sha1_to_hex

[Eric Sunshine]

On Thu, Sep 24, 2015 at 5:08 PM, Jeff King <peff@peff.net> wrote:
> In some cases where we strcpy() the result of sha1_to_hex(),
> there's no need; the result goes directly into a printf
> statement, and we can simply pass the return value from
> sha1_to_hex() directly.
>
> When this code was originally written, sha1_to_hex used a
> single buffer, and it was not safe to use it twice within a
> single expression. That changed as of dcb3450 (sha1_to_hex()
> usage cleanup, 2006-05-03), but this code ewas never

s/ewas/was/

> updated.
>
> History-dug-by: Eric Sunshine <sunshine@sunshineco.com>
> Signed-off-by: Jeff King <peff@peff.net>

Re: [PATCH 54/68] drop strcpy in favor of raw sha1_to_hex

[Jeff King]

On Thu, Sep 24, 2015 at 07:42:05PM -0400, Eric Sunshine wrote:

> On Thu, Sep 24, 2015 at 5:08 PM, Jeff King <peff@peff.net> wrote:
> > In some cases where we strcpy() the result of sha1_to_hex(),
> > there's no need; the result goes directly into a printf
> > statement, and we can simply pass the return value from
> > sha1_to_hex() directly.
> >
> > When this code was originally written, sha1_to_hex used a
> > single buffer, and it was not safe to use it twice within a
> > single expression. That changed as of dcb3450 (sha1_to_hex()
> > usage cleanup, 2006-05-03), but this code ewas never
> 
> s/ewas/was/

Whoops. New content, new errors. :)

-Peff

Re: [PATCH 66/68] fsck: use for_each_loose_file_in_objdir

[Jeff King]

On Thu, Sep 24, 2015 at 05:08:32PM -0400, Jeff King wrote:

> +static int fsck_subdir(int nr, const char *path, void *progress)
> +{
> +	display_progress(progress, nr + 1);
> +	return 0;
> +}
> +
>  static void fsck_object_dir(const char *path)
>  {
> -	int i;
>  	struct progress *progress = NULL;
>  
>  	if (verbose)
> @@ -501,12 +481,9 @@ static void fsck_object_dir(const char *path)
>  
>  	if (show_progress)
>  		progress = start_progress(_("Checking object directories"), 256);
> -	for (i = 0; i < 256; i++) {
> -		static char dir[4096];
> -		sprintf(dir, "%s/%02x", path, i);
> -		fsck_dir(i, dir);
> -		display_progress(progress, i+1);
> -	}
> +
> +	for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
> +				      progress);
>  	stop_progress(&progress);

I happened to be running git-fsck today and noticed that it finished
with the progress bar still reading 94%. The problem is that we update
the progress when we finish a subdir, but of course we do not
necessarily have all 256 subdirs, and the for_each_loose code only
triggers our callback for ones that exist.

So we need this on top:

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 2fe6a31..d50efd5 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -484,6 +484,7 @@ static void fsck_object_dir(const char *path)
 
 	for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
 				      progress);
+	display_progress(progress, 256);
 	stop_progress(&progress);
 }
 

to make things pretty.

-Peff

Re: [PATCH 60/68] prefer memcpy to strcpy

[René Scharfe]

Am 24.09.2015 um 23:08 schrieb Jeff King:
> When we already know the length of a string (e.g., because
> we just malloc'd to fit it), it's nicer to use memcpy than
> strcpy, as it makes it more obvious that we are not going to
> overflow the buffer (because the size we pass matches the
> size in the allocation).
>
> This also eliminates calls to strcpy, which make auditing
> the code base harder.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
>   compat/nedmalloc/nedmalloc.c | 5 +++--
>   fast-import.c                | 5 +++--
>   revision.c                   | 2 +-
>   3 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
> index 609ebba..a0a16eb 100644
> --- a/compat/nedmalloc/nedmalloc.c
> +++ b/compat/nedmalloc/nedmalloc.c
> @@ -957,8 +957,9 @@ char *strdup(const char *s1)
>   {
>   	char *s2 = 0;
>   	if (s1) {
> -		s2 = malloc(strlen(s1) + 1);
> -		strcpy(s2, s1);
> +		size_t len = strlen(s1) + 1;
> +		s2 = malloc(len);
> +		memcpy(s2, s1, len);

This leaves the last byte uninitialized; it was set to NUL by strcpy() 
before.

>   	}
>   	return s2;
>   }
> diff --git a/fast-import.c b/fast-import.c
> index 895c6b4..cf6d8bc 100644
> --- a/fast-import.c
> +++ b/fast-import.c
> @@ -644,8 +644,9 @@ static void *pool_calloc(size_t count, size_t size)
>
>   static char *pool_strdup(const char *s)
>   {
> -	char *r = pool_alloc(strlen(s) + 1);
> -	strcpy(r, s);
> +	size_t len = strlen(s) + 1;
> +	char *r = pool_alloc(len);
> +	memcpy(r, s, len);

Same here.

>   	return r;
>   }
>
> diff --git a/revision.c b/revision.c
> index af2a18e..2236463 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -38,7 +38,7 @@ char *path_name(const struct name_path *path, const char *name)
>   	}
>   	n = xmalloc(len);
>   	m = n + len - (nlen + 1);
> -	strcpy(m, name);
> +	memcpy(m, name, nlen + 1);

This copies the NUL byte terminating the string, so it's OK.  However, I 
wonder if using a strbuf for building the path in one go instead would 
simplify this function without too much of a performance impact.

>   	for (p = path; p; p = p->up) {
>   		if (p->elem_len) {
>   			m -= p->elem_len + 1;
>

Re: [PATCH 60/68] prefer memcpy to strcpy

[Torsten Bögershausen]

On 2015-09-27 13.19, René Scharfe wrote:
> Am 24.09.2015 um 23:08 schrieb Jeff King:
>> When we already know the length of a string (e.g., because
>> we just malloc'd to fit it), it's nicer to use memcpy than
>> strcpy, as it makes it more obvious that we are not going to
>> overflow the buffer (because the size we pass matches the
>> size in the allocation).
>>
>> This also eliminates calls to strcpy, which make auditing
>> the code base harder.
>>
>> Signed-off-by: Jeff King <peff@peff.net>
>> ---
>>   compat/nedmalloc/nedmalloc.c | 5 +++--
>>   fast-import.c                | 5 +++--
>>   revision.c                   | 2 +-
>>   3 files changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
>> index 609ebba..a0a16eb 100644
>> --- a/compat/nedmalloc/nedmalloc.c
>> +++ b/compat/nedmalloc/nedmalloc.c
>> @@ -957,8 +957,9 @@ char *strdup(const char *s1)
>>   {
>>       char *s2 = 0;
>>       if (s1) {
>> -        s2 = malloc(strlen(s1) + 1);
>> -        strcpy(s2, s1);
>> +        size_t len = strlen(s1) + 1;
>> +        s2 = malloc(len);
>> +        memcpy(s2, s1, len);
> 
> This leaves the last byte uninitialized; it was set to NUL by strcpy() before.

len is == strlen() +1, which should cover the NUL:

1 byte extra for NUL is allocated,
and memcpy will copy NUL from source.
(Or do I miss somethong ?)

Re: [PATCH 60/68] prefer memcpy to strcpy

[René Scharfe]

Am 27.09.2015 um 15:06 schrieb Torsten Bögershausen:
> On 2015-09-27 13.19, René Scharfe wrote:
>> Am 24.09.2015 um 23:08 schrieb Jeff King:
>>> When we already know the length of a string (e.g., because
>>> we just malloc'd to fit it), it's nicer to use memcpy than
>>> strcpy, as it makes it more obvious that we are not going to
>>> overflow the buffer (because the size we pass matches the
>>> size in the allocation).
>>>
>>> This also eliminates calls to strcpy, which make auditing
>>> the code base harder.
>>>
>>> Signed-off-by: Jeff King <peff@peff.net>
>>> ---
>>>    compat/nedmalloc/nedmalloc.c | 5 +++--
>>>    fast-import.c                | 5 +++--
>>>    revision.c                   | 2 +-
>>>    3 files changed, 7 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
>>> index 609ebba..a0a16eb 100644
>>> --- a/compat/nedmalloc/nedmalloc.c
>>> +++ b/compat/nedmalloc/nedmalloc.c
>>> @@ -957,8 +957,9 @@ char *strdup(const char *s1)
>>>    {
>>>        char *s2 = 0;
>>>        if (s1) {
>>> -        s2 = malloc(strlen(s1) + 1);
>>> -        strcpy(s2, s1);
>>> +        size_t len = strlen(s1) + 1;
>>> +        s2 = malloc(len);
>>> +        memcpy(s2, s1, len);
>>
>> This leaves the last byte uninitialized; it was set to NUL by strcpy() before.
>
> len is == strlen() +1, which should cover the NUL:
>
> 1 byte extra for NUL is allocated,
> and memcpy will copy NUL from source.
> (Or do I miss somethong ?)

No, you're right.  Sorry for the noise.

I fully blame this on lack of coffeine because my electric kettle just 
broke. O_o

René

Re: [PATCH 60/68] prefer memcpy to strcpy

[René Scharfe]

Am 27.09.2015 um 15:13 schrieb René Scharfe:
> Am 27.09.2015 um 15:06 schrieb Torsten Bögershausen:
>> On 2015-09-27 13.19, René Scharfe wrote:
>>> Am 24.09.2015 um 23:08 schrieb Jeff King:
>>>> When we already know the length of a string (e.g., because
>>>> we just malloc'd to fit it), it's nicer to use memcpy than
>>>> strcpy, as it makes it more obvious that we are not going to
>>>> overflow the buffer (because the size we pass matches the
>>>> size in the allocation).
>>>>
>>>> This also eliminates calls to strcpy, which make auditing
>>>> the code base harder.
>>>>
>>>> Signed-off-by: Jeff King <peff@peff.net>
>>>> ---
>>>>    compat/nedmalloc/nedmalloc.c | 5 +++--
>>>>    fast-import.c                | 5 +++--
>>>>    revision.c                   | 2 +-
>>>>    3 files changed, 7 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/compat/nedmalloc/nedmalloc.c
>>>> b/compat/nedmalloc/nedmalloc.c
>>>> index 609ebba..a0a16eb 100644
>>>> --- a/compat/nedmalloc/nedmalloc.c
>>>> +++ b/compat/nedmalloc/nedmalloc.c
>>>> @@ -957,8 +957,9 @@ char *strdup(const char *s1)
>>>>    {
>>>>        char *s2 = 0;
>>>>        if (s1) {
>>>> -        s2 = malloc(strlen(s1) + 1);
>>>> -        strcpy(s2, s1);
>>>> +        size_t len = strlen(s1) + 1;
>>>> +        s2 = malloc(len);
>>>> +        memcpy(s2, s1, len);
>>>
>>> This leaves the last byte uninitialized; it was set to NUL by
>>> strcpy() before.
>>
>> len is == strlen() +1, which should cover the NUL:
>>
>> 1 byte extra for NUL is allocated,
>> and memcpy will copy NUL from source.
>> (Or do I miss somethong ?)
>
> No, you're right.  Sorry for the noise.
>
> I fully blame this on lack of coffeine because my electric kettle just
> broke. O_o

Thinking a bit more about it (slowly): The choice of the variable name 
might have been a factor as well.  When I see "len" for a string then I 
don't expect it to include the trailing NUL.  "size" would be better 
because I expect it to contain the number of bytes needed to store an 
object.

René

Re: [PATCH 60/68] prefer memcpy to strcpy

[Rasmus Villemoes]

On Thu, Sep 24 2015, Jeff King <peff@peff.net> wrote:

> This also eliminates calls to strcpy, which make auditing
> the code base harder.

Maybe may English parser is broken, but this doesn't immediately sound
like what you meant to say. Also, in 29/68 you say "We drop calls to
strcpy, which makes auditing the code base easier." Maybe it's all ok,
since on second reading the first "make" probably refers to the plural
"calls for strcpy", while in the second case "makes" refers to "[the
dropping of] calls to strcpy".

Rasmus

Re: [PATCH 41/68] init: use strbufs to store paths

[Michael Blume]

On Thu, Sep 24, 2015 at 2:07 PM, Jeff King <peff@peff.net> wrote:
> The init code predates strbufs, and uses PATH_MAX-sized
> buffers along with many manual checks on intermediate sizes
> (some of which make magic assumptions, such as that init
> will not create a path inside .git longer than 50
> characters).
>
> We can simplify this greatly by using strbufs, which drops
> some hard-to-verify strcpy calls.  Note that we need to
> update probe_utf8_pathname_composition, too, as it assumes
> we are passing a buffer large enough to append its probe
> filenames (it now just takes a strbuf, which also gets rid
> of the confusing "len" parameter, which was not the length of
> "path" but rather the offset to start writing).
>
> Some of the conversion makes new calls to git_path_buf.
> While we're in the area, let's also convert existing calls
> to git_path to the safer git_path_buf (our existing calls
> were passed to pretty tame functions, and so were not a
> problem, but it's easy to be consistent and safe here).
>
> Note that we had an explicit test that "git init" rejects
> long template directories. This comes from 32d1776 (init: Do
> not segfault on big GIT_TEMPLATE_DIR environment variable,
> 2009-04-18). We can drop the test_must_fail here, as we now
> accept this and need only confirm that we don't segfault,
> which was the original point of the test.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  builtin/init-db.c        | 174 ++++++++++++++++++++---------------------------
>  compat/precompose_utf8.c |  12 ++--
>  compat/precompose_utf8.h |   2 +-
>  git-compat-util.h        |   2 +-
>  t/t0001-init.sh          |   4 +-
>  5 files changed, 87 insertions(+), 107 deletions(-)
>
> diff --git a/builtin/init-db.c b/builtin/init-db.c
> index e7d0e31..cf6a3c8 100644
> --- a/builtin/init-db.c
> +++ b/builtin/init-db.c
> @@ -36,10 +36,11 @@ static void safe_create_dir(const char *dir, int share)
>                 die(_("Could not make %s writable by group"), dir);
>  }
>
> -static void copy_templates_1(char *path, int baselen,
> -                            char *template, int template_baselen,
> +static void copy_templates_1(struct strbuf *path, struct strbuf *template,
>                              DIR *dir)
>  {
> +       size_t path_baselen = path->len;
> +       size_t template_baselen = template->len;
>         struct dirent *de;
>
>         /* Note: if ".git/hooks" file exists in the repository being
> @@ -49,77 +50,64 @@ static void copy_templates_1(char *path, int baselen,
>          * with the way the namespace under .git/ is organized, should
>          * be really carefully chosen.
>          */
> -       safe_create_dir(path, 1);
> +       safe_create_dir(path->buf, 1);
>         while ((de = readdir(dir)) != NULL) {
>                 struct stat st_git, st_template;
> -               int namelen;
>                 int exists = 0;
>
> +               strbuf_setlen(path, path_baselen);
> +               strbuf_setlen(template, template_baselen);
> +
>                 if (de->d_name[0] == '.')
>                         continue;
> -               namelen = strlen(de->d_name);
> -               if ((PATH_MAX <= baselen + namelen) ||
> -                   (PATH_MAX <= template_baselen + namelen))
> -                       die(_("insanely long template name %s"), de->d_name);
> -               memcpy(path + baselen, de->d_name, namelen+1);
> -               memcpy(template + template_baselen, de->d_name, namelen+1);
> -               if (lstat(path, &st_git)) {
> +               strbuf_addstr(path, de->d_name);
> +               strbuf_addstr(template, de->d_name);
> +               if (lstat(path->buf, &st_git)) {
>                         if (errno != ENOENT)
> -                               die_errno(_("cannot stat '%s'"), path);
> +                               die_errno(_("cannot stat '%s'"), path->buf);
>                 }
>                 else
>                         exists = 1;
>
> -               if (lstat(template, &st_template))
> -                       die_errno(_("cannot stat template '%s'"), template);
> +               if (lstat(template->buf, &st_template))
> +                       die_errno(_("cannot stat template '%s'"), template->buf);
>
>                 if (S_ISDIR(st_template.st_mode)) {
> -                       DIR *subdir = opendir(template);
> -                       int baselen_sub = baselen + namelen;
> -                       int template_baselen_sub = template_baselen + namelen;
> +                       DIR *subdir = opendir(template->buf);
>                         if (!subdir)
> -                               die_errno(_("cannot opendir '%s'"), template);
> -                       path[baselen_sub++] =
> -                               template[template_baselen_sub++] = '/';
> -                       path[baselen_sub] =
> -                               template[template_baselen_sub] = 0;
> -                       copy_templates_1(path, baselen_sub,
> -                                        template, template_baselen_sub,
> -                                        subdir);
> +                               die_errno(_("cannot opendir '%s'"), template->buf);
> +                       strbuf_addch(path, '/');
> +                       strbuf_addch(template, '/');
> +                       copy_templates_1(path, template, subdir);
>                         closedir(subdir);
>                 }
>                 else if (exists)
>                         continue;
>                 else if (S_ISLNK(st_template.st_mode)) {
> -                       char lnk[256];
> -                       int len;
> -                       len = readlink(template, lnk, sizeof(lnk));
> -                       if (len < 0)
> -                               die_errno(_("cannot readlink '%s'"), template);
> -                       if (sizeof(lnk) <= len)
> -                               die(_("insanely long symlink %s"), template);
> -                       lnk[len] = 0;
> -                       if (symlink(lnk, path))
> -                               die_errno(_("cannot symlink '%s' '%s'"), lnk, path);
> +                       struct strbuf lnk = STRBUF_INIT;
> +                       if (strbuf_readlink(&lnk, template->buf, 0) < 0)
> +                               die_errno(_("cannot readlink '%s'"), template->buf);
> +                       if (symlink(lnk.buf, path->buf))
> +                               die_errno(_("cannot symlink '%s' '%s'"),
> +                                         lnk.buf, path->buf);
> +                       strbuf_release(&lnk);
>                 }
>                 else if (S_ISREG(st_template.st_mode)) {
> -                       if (copy_file(path, template, st_template.st_mode))
> -                               die_errno(_("cannot copy '%s' to '%s'"), template,
> -                                         path);
> +                       if (copy_file(path->buf, template->buf, st_template.st_mode))
> +                               die_errno(_("cannot copy '%s' to '%s'"),
> +                                         template->buf, path->buf);
>                 }
>                 else
> -                       error(_("ignoring template %s"), template);
> +                       error(_("ignoring template %s"), template->buf);
>         }
>  }
>
>  static void copy_templates(const char *template_dir)
>  {
> -       char path[PATH_MAX];
> -       char template_path[PATH_MAX];
> -       int template_len;
> +       struct strbuf path = STRBUF_INIT;
> +       struct strbuf template_path = STRBUF_INIT;
> +       size_t template_len;
>         DIR *dir;
> -       const char *git_dir = get_git_dir();
> -       int len = strlen(git_dir);
>         char *to_free = NULL;
>
>         if (!template_dir)
> @@ -132,26 +120,23 @@ static void copy_templates(const char *template_dir)
>                 free(to_free);
>                 return;
>         }
> -       template_len = strlen(template_dir);
> -       if (PATH_MAX <= (template_len+strlen("/config")))
> -               die(_("insanely long template path %s"), template_dir);
> -       strcpy(template_path, template_dir);
> -       if (template_path[template_len-1] != '/') {
> -               template_path[template_len++] = '/';
> -               template_path[template_len] = 0;
> -       }
> -       dir = opendir(template_path);
> +
> +       strbuf_addstr(&template_path, template_dir);
> +       strbuf_complete(&template_path, '/');
> +       template_len = template_path.len;
> +
> +       dir = opendir(template_path.buf);
>         if (!dir) {
>                 warning(_("templates not found %s"), template_dir);
>                 goto free_return;
>         }
>
>         /* Make sure that template is from the correct vintage */
> -       strcpy(template_path + template_len, "config");
> +       strbuf_addstr(&template_path, "config");
>         repository_format_version = 0;
>         git_config_from_file(check_repository_format_version,
> -                            template_path, NULL);
> -       template_path[template_len] = 0;
> +                            template_path.buf, NULL);
> +       strbuf_setlen(&template_path, template_len);
>
>         if (repository_format_version &&
>             repository_format_version != GIT_REPO_VERSION) {
> @@ -162,17 +147,15 @@ static void copy_templates(const char *template_dir)
>                 goto close_free_return;
>         }
>
> -       memcpy(path, git_dir, len);
> -       if (len && path[len - 1] != '/')
> -               path[len++] = '/';
> -       path[len] = 0;
> -       copy_templates_1(path, len,
> -                        template_path, template_len,
> -                        dir);
> +       strbuf_addstr(&path, get_git_dir());
> +       strbuf_complete(&path, '/');
> +       copy_templates_1(&path, &template_path, dir);
>  close_free_return:
>         closedir(dir);
>  free_return:
>         free(to_free);
> +       strbuf_release(&path);
> +       strbuf_release(&template_path);
>  }
>
>  static int git_init_db_config(const char *k, const char *v, void *cb)
> @@ -199,28 +182,20 @@ static int needs_work_tree_config(const char *git_dir, const char *work_tree)
>
>  static int create_default_files(const char *template_path)
>  {
> -       const char *git_dir = get_git_dir();
> -       unsigned len = strlen(git_dir);
> -       static char path[PATH_MAX];
>         struct stat st1;
> +       struct strbuf buf = STRBUF_INIT;
> +       char *path;
>         char repo_version_string[10];
>         char junk[2];
>         int reinit;
>         int filemode;
>
> -       if (len > sizeof(path)-50)
> -               die(_("insane git directory %s"), git_dir);
> -       memcpy(path, git_dir, len);
> -
> -       if (len && path[len-1] != '/')
> -               path[len++] = '/';
> -
>         /*
>          * Create .git/refs/{heads,tags}
>          */
> -       safe_create_dir(git_path("refs"), 1);
> -       safe_create_dir(git_path("refs/heads"), 1);
> -       safe_create_dir(git_path("refs/tags"), 1);
> +       safe_create_dir(git_path_buf(&buf, "refs"), 1);
> +       safe_create_dir(git_path_buf(&buf, "refs/heads"), 1);
> +       safe_create_dir(git_path_buf(&buf, "refs/tags"), 1);
>
>         /* Just look for `init.templatedir` */
>         git_config(git_init_db_config, NULL);
> @@ -244,16 +219,16 @@ static int create_default_files(const char *template_path)
>          */
>         if (shared_repository) {
>                 adjust_shared_perm(get_git_dir());
> -               adjust_shared_perm(git_path("refs"));
> -               adjust_shared_perm(git_path("refs/heads"));
> -               adjust_shared_perm(git_path("refs/tags"));
> +               adjust_shared_perm(git_path_buf(&buf, "refs"));
> +               adjust_shared_perm(git_path_buf(&buf, "refs/heads"));
> +               adjust_shared_perm(git_path_buf(&buf, "refs/tags"));
>         }
>
>         /*
>          * Create the default symlink from ".git/HEAD" to the "master"
>          * branch, if it does not exist yet.
>          */
> -       strcpy(path + len, "HEAD");
> +       path = git_path_buf(&buf, "HEAD");
>         reinit = (!access(path, R_OK)
>                   || readlink(path, junk, sizeof(junk)-1) != -1);
>         if (!reinit) {
> @@ -266,10 +241,8 @@ static int create_default_files(const char *template_path)
>                   "%d", GIT_REPO_VERSION);
>         git_config_set("core.repositoryformatversion", repo_version_string);
>
> -       path[len] = 0;
> -       strcpy(path + len, "config");
> -
>         /* Check filemode trustability */
> +       path = git_path_buf(&buf, "config");
>         filemode = TEST_FILEMODE;
>         if (TEST_FILEMODE && !lstat(path, &st1)) {
>                 struct stat st2;
> @@ -290,14 +263,13 @@ static int create_default_files(const char *template_path)
>                 /* allow template config file to override the default */
>                 if (log_all_ref_updates == -1)
>                     git_config_set("core.logallrefupdates", "true");
> -               if (needs_work_tree_config(git_dir, work_tree))
> +               if (needs_work_tree_config(get_git_dir(), work_tree))
>                         git_config_set("core.worktree", work_tree);
>         }
>
>         if (!reinit) {
>                 /* Check if symlink is supported in the work tree */
> -               path[len] = 0;
> -               strcpy(path + len, "tXXXXXX");
> +               path = git_path_buf(&buf, "tXXXXXX");
>                 if (!close(xmkstemp(path)) &&
>                     !unlink(path) &&
>                     !symlink("testing", path) &&
> @@ -308,31 +280,35 @@ static int create_default_files(const char *template_path)
>                         git_config_set("core.symlinks", "false");
>
>                 /* Check if the filesystem is case-insensitive */
> -               path[len] = 0;
> -               strcpy(path + len, "CoNfIg");
> +               path = git_path_buf(&buf, "CoNfIg");
>                 if (!access(path, F_OK))
>                         git_config_set("core.ignorecase", "true");
> -               probe_utf8_pathname_composition(path, len);
> +               probe_utf8_pathname_composition(path);
>         }
>
> +       strbuf_release(&buf);
>         return reinit;
>  }
>
>  static void create_object_directory(void)
>  {
> -       const char *object_directory = get_object_directory();
> -       int len = strlen(object_directory);
> -       char *path = xmalloc(len + 40);
> +       struct strbuf path = STRBUF_INIT;
> +       size_t baselen;
> +
> +       strbuf_addstr(&path, get_object_directory());
> +       baselen = path.len;
> +
> +       safe_create_dir(path.buf, 1);
>
> -       memcpy(path, object_directory, len);
> +       strbuf_setlen(&path, baselen);
> +       strbuf_addstr(&path, "/pack");
> +       safe_create_dir(path.buf, 1);
>
> -       safe_create_dir(object_directory, 1);
> -       strcpy(path+len, "/pack");
> -       safe_create_dir(path, 1);
> -       strcpy(path+len, "/info");
> -       safe_create_dir(path, 1);
> +       strbuf_setlen(&path, baselen);
> +       strbuf_addstr(&path, "/info");
> +       safe_create_dir(path.buf, 1);
>
> -       free(path);
> +       strbuf_release(&path);
>  }
>
>  int set_git_dir_init(const char *git_dir, const char *real_git_dir,
> diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
> index 95fe849..b4dd3c7 100644
> --- a/compat/precompose_utf8.c
> +++ b/compat/precompose_utf8.c
> @@ -36,24 +36,28 @@ static size_t has_non_ascii(const char *s, size_t maxlen, size_t *strlen_c)
>  }
>
>
> -void probe_utf8_pathname_composition(char *path, int len)
> +void probe_utf8_pathname_composition(struct strbuf *path)
>  {
>         static const char *auml_nfc = "\xc3\xa4";
>         static const char *auml_nfd = "\x61\xcc\x88";
> +       size_t baselen = path->len;
>         int output_fd;
>         if (precomposed_unicode != -1)
>                 return; /* We found it defined in the global config, respect it */
> -       strcpy(path + len, auml_nfc);
> +       strbuf_addstr(path, auml_nfc);
>         output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
>         if (output_fd >= 0) {
>                 close(output_fd);
> -               strcpy(path + len, auml_nfd);
> +               strbuf_setlen(path, baselen);
> +               strbuf_addstr(path, auml_nfd);
>                 precomposed_unicode = access(path, R_OK) ? 0 : 1;
>                 git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
> -               strcpy(path + len, auml_nfc);
> +               strbuf_setlen(path, baselen);
> +               strbuf_addstr(path, auml_nfc);
>                 if (unlink(path))
>                         die_errno(_("failed to unlink '%s'"), path);
>         }
> +       strbuf_setlen(path, baselen);
>  }
>
>
> diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
> index 3b73585..7fc7be5 100644
> --- a/compat/precompose_utf8.h
> +++ b/compat/precompose_utf8.h
> @@ -27,7 +27,7 @@ typedef struct {
>  } PREC_DIR;
>
>  void precompose_argv(int argc, const char **argv);
> -void probe_utf8_pathname_composition(char *, int);
> +void probe_utf8_pathname_composition(struct strbuf *path);
>
>  PREC_DIR *precompose_utf8_opendir(const char *dirname);
>  struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 348b9dc..712de7f 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -229,7 +229,7 @@ typedef unsigned long uintptr_t;
>  #else
>  #define precompose_str(in,i_nfd2nfc)
>  #define precompose_argv(c,v)
> -#define probe_utf8_pathname_composition(a,b)
> +#define probe_utf8_pathname_composition(p)
>  #endif
>
>  #ifdef MKDIR_WO_TRAILING_SLASH
> diff --git a/t/t0001-init.sh b/t/t0001-init.sh
> index 7de8d85..f91bbcf 100755
> --- a/t/t0001-init.sh
> +++ b/t/t0001-init.sh
> @@ -202,8 +202,8 @@ test_expect_success 'init honors global core.sharedRepository' '
>         x$(git config -f shared-honor-global/.git/config core.sharedRepository)
>  '
>
> -test_expect_success 'init rejects insanely long --template' '
> -       test_must_fail git init --template=$(printf "x%09999dx" 1) test
> +test_expect_success 'init allows insanely long --template' '
> +       git init --template=$(printf "x%09999dx" 1) test
>  '
>
>  test_expect_success 'init creates a new directory' '
> --
> 2.6.0.rc3.454.g204ad51
>
> --
> To unsubscribe from this list: send the line "unsubscribe git" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

I see compile errors on my mac:

First a whole bunch of

./compat/precompose_utf8.h:30:45: warning: declaration of 'struct
strbuf' will not be visible outside of this function [-Wvisibility]
void probe_utf8_pathname_composition(struct strbuf *path);
                                            ^
1 warning generated.
    CC trace.o
In file included from trace.c:25:
In file included from ./cache.h:4:
In file included from ./git-compat-util.h:228:

and then

compat/precompose_utf8.c:39:6: error: conflicting types for
'probe_utf8_pathname_composition'
void probe_utf8_pathname_composition(struct strbuf *path)
     ^
compat/precompose_utf8.h:30:6: note: previous declaration is here
void probe_utf8_pathname_composition(struct strbuf *path);
     ^
compat/precompose_utf8.c:48:19: warning: incompatible pointer types
passing 'struct strbuf *' to parameter of type 'const char *'
[-Wincompatible-pointer-types]
        output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
                         ^~~~
/usr/include/sys/fcntl.h:470:22: note: passing argument to parameter here
int     open(const char *, int, ...) __DARWIN_ALIAS_C(open);
                         ^
compat/precompose_utf8.c:53:32: warning: incompatible pointer types
passing 'struct strbuf *' to parameter of type 'const char *'
[-Wincompatible-pointer-types]
                precomposed_unicode = access(path, R_OK) ? 0 : 1;
                                             ^~~~
/usr/include/unistd.h:425:25: note: passing argument to parameter here
int      access(const char *, int);
                            ^
compat/precompose_utf8.c:57:14: warning: incompatible pointer types
passing 'struct strbuf *' to parameter of type 'const char *'
[-Wincompatible-pointer-types]
                if (unlink(path))
                           ^~~~
/usr/include/unistd.h:488:25: note: passing argument to parameter here
int      unlink(const char *);
                            ^
compat/precompose_utf8.c:58:42: warning: format specifies type 'char
*' but the argument has type 'struct strbuf *' [-Wformat]
                        die_errno(_("failed to unlink '%s'"), path);
                                                       ~~     ^~~~
5 warnings and 1 error generated.
make: *** [compat/precompose_utf8.o] Error 1

Re: [PATCH 41/68] init: use strbufs to store paths

[Jeff King]

On Tue, Sep 29, 2015 at 04:50:39PM -0700, Michael Blume wrote:

> I see compile errors on my mac:
> 
> First a whole bunch of
> 
> ./compat/precompose_utf8.h:30:45: warning: declaration of 'struct
> strbuf' will not be visible outside of this function [-Wvisibility]
> void probe_utf8_pathname_composition(struct strbuf *path);

Wow, my patch isn't even close to reasonable. I didn't realize because
we do not compile this code at all for non-Mac platforms. Sorry.

It probably needs something like this squashed in (completely untested):

diff --git a/builtin/init-db.c b/builtin/init-db.c
index cf6a3c8..c643054 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -283,7 +283,7 @@ static int create_default_files(const char *template_path)
 		path = git_path_buf(&buf, "CoNfIg");
 		if (!access(path, F_OK))
 			git_config_set("core.ignorecase", "true");
-		probe_utf8_pathname_composition(path);
+		probe_utf8_pathname_composition(&buf);
 	}
 
 	strbuf_release(&buf);
diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index b4dd3c7..d2d2405 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -8,6 +8,7 @@
 #include "cache.h"
 #include "utf8.h"
 #include "precompose_utf8.h"
+#include "strbuf.h"
 
 typedef char *iconv_ibp;
 static const char *repo_encoding = "UTF-8";
@@ -45,17 +46,17 @@ void probe_utf8_pathname_composition(struct strbuf *path)
 	if (precomposed_unicode != -1)
 		return; /* We found it defined in the global config, respect it */
 	strbuf_addstr(path, auml_nfc);
-	output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
+	output_fd = open(path->buf, O_CREAT|O_EXCL|O_RDWR, 0600);
 	if (output_fd >= 0) {
 		close(output_fd);
 		strbuf_setlen(path, baselen);
 		strbuf_addstr(path, auml_nfd);
-		precomposed_unicode = access(path, R_OK) ? 0 : 1;
+		precomposed_unicode = access(path->buf, R_OK) ? 0 : 1;
 		git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
 		strbuf_setlen(path, baselen);
 		strbuf_addstr(path, auml_nfc);
-		if (unlink(path))
-			die_errno(_("failed to unlink '%s'"), path);
+		if (unlink(path->buf))
+			die_errno(_("failed to unlink '%s'"), path->buf);
 	}
 	strbuf_setlen(path, baselen);
 }
diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
index 7fc7be5..229e772 100644
--- a/compat/precompose_utf8.h
+++ b/compat/precompose_utf8.h
@@ -4,6 +4,7 @@
 #include <dirent.h>
 #include <iconv.h>
 
+struct strbuf;
 
 typedef struct dirent_prec_psx {
 	ino_t d_ino;            /* Posix */

Re: [PATCH 41/68] init: use strbufs to store paths

[Junio C Hamano]

Jeff King <peff@peff.net> writes:

> On Tue, Sep 29, 2015 at 04:50:39PM -0700, Michael Blume wrote:
>
>> I see compile errors on my mac:
>> 
>> First a whole bunch of
>> 
>> ./compat/precompose_utf8.h:30:45: warning: declaration of 'struct
>> strbuf' will not be visible outside of this function [-Wvisibility]
>> void probe_utf8_pathname_composition(struct strbuf *path);
>
> Wow, my patch isn't even close to reasonable. I didn't realize because
> we do not compile this code at all for non-Mac platforms. Sorry.

Perhaps the way we completely stub out the platform specific helpers
contributes to this kind of gotchas?  I am wondering how much additional
safety we would gain if we start doing something like this.

Two things to note:

 * "struct strbuf" needs to be visible when the compiler sees this
   part, which is an indication of the same issue shown in the above
   error message, is not addressed.

 * precompose_str() does not seem to be defined or used, hence
   removed.

 git-compat-util.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index 712de7f..6710ff7 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -227,9 +227,11 @@ typedef unsigned long uintptr_t;
 #ifdef PRECOMPOSE_UNICODE
 #include "compat/precompose_utf8.h"
 #else
-#define precompose_str(in,i_nfd2nfc)
-#define precompose_argv(c,v)
-#define probe_utf8_pathname_composition(p)
+static inline void precompose_argv(int, const char **);
+static inline void probe_utf8_pathname_composition(struct strbuf *buf)
+{
+	; /* no-op */
+}
 #endif
 
 #ifdef MKDIR_WO_TRAILING_SLASH

Re: [PATCH 41/68] init: use strbufs to store paths

[Jeff King]

On Wed, Sep 30, 2015 at 01:00:56PM -0700, Junio C Hamano wrote:

> > Wow, my patch isn't even close to reasonable. I didn't realize because
> > we do not compile this code at all for non-Mac platforms. Sorry.
> 
> Perhaps the way we completely stub out the platform specific helpers
> contributes to this kind of gotchas?  I am wondering how much additional
> safety we would gain if we start doing something like this.

I think it is an improvement, but it does not solve all of the problems.
I also botched the implementation of probe_utf8_pathname_composition,
and that does not get compiled on most platforms (though we _could_
compile it and just never call it).

-Peff

Re: [PATCH 41/68] init: use strbufs to store paths

[Torsten Bögershausen]

On 10/01/2015 04:51 AM, Jeff King wrote:
> On Wed, Sep 30, 2015 at 01:00:56PM -0700, Junio C Hamano wrote:
>
>>> Wow, my patch isn't even close to reasonable. I didn't realize because
>>> we do not compile this code at all for non-Mac platforms. Sorry.
>> Perhaps the way we completely stub out the platform specific helpers
>> contributes to this kind of gotchas?  I am wondering how much additional
>> safety we would gain if we start doing something like this.
> I think it is an improvement, but it does not solve all of the problems.
> I also botched the implementation of probe_utf8_pathname_composition,
> and that does not get compiled on most platforms (though we _could_
> compile it and just never call it).
>
> -Peff
>
Peff, are you planing a re-roll ?
Or. Junio, do you plan to fix it ?
Or should I send a patch on top of pu ?

The compilation can be tested under Linux like this:

diff --git a/config.mak.uname b/config.mak.uname
index 7486a7e..6d09bd0 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -13,6 +13,9 @@ ifdef MSVC
         uname_O := Windows
  endif

+COMPAT_OBJS += compat/precompose_utf8.o
+BASIC_CFLAGS += -DPRECOMPOSE_UNICODE
+

Re: [PATCH 41/68] init: use strbufs to store paths

[Jeff King]

On Fri, Oct 02, 2015 at 08:00:24AM +0200, Torsten Bögershausen wrote:

> Peff, are you planing a re-roll ?
> Or. Junio, do you plan to fix it ?
> Or should I send a patch on top of pu ?

I am on vacation, so I am hoping that somebody on OS X can confirm that
the patch that I sent earlier does indeed fix it, and that Junio
can squash it in.

Makefile hack similar to what you posted, but I cannot actually on Linux
that the code does what it should).

> The compilation can be tested under Linux like this:

Yeah, I did something similar to see that it at least compiled, but I
don't have an easy way to actually run t3910.

-Peff

Re: [PATCH 41/68] init: use strbufs to store paths

[Torsten Bögershausen]

On 30.09.15 02:23, Jeff King wrote:
> On Tue, Sep 29, 2015 at 04:50:39PM -0700, Michael Blume wrote:
> 
>> I see compile errors on my mac:
>>

This is my attempt, passing the test, but not fully polished.




diff --git a/builtin/init-db.c b/builtin/init-db.c
index 89f2c05..60b559c 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -276,7 +276,9 @@ static int create_default_files(const char *template_path)
 		path = git_path_buf(&buf, "CoNfIg");
 		if (!access(path, F_OK))
 			git_config_set("core.ignorecase", "true");
-		probe_utf8_pathname_composition(path);
+		/* Probe utf-8 normalization withou mangling CoNfIG */
+		path = git_path_buf(&buf, "config");
+		probe_utf8_pathname_composition(path, strlen(path));
 	}
 
 	strbuf_release(&buf);
diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index b4dd3c7..37172a4 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -8,6 +8,7 @@
 #include "cache.h"
 #include "utf8.h"
 #include "precompose_utf8.h"
+#include "strbuf.h"
 
 typedef char *iconv_ibp;
 static const char *repo_encoding = "UTF-8";
@@ -36,28 +37,33 @@ static size_t has_non_ascii(const char *s, size_t maxlen, size_t *strlen_c)
 }
 
 
-void probe_utf8_pathname_composition(struct strbuf *path)
+void probe_utf8_pathname_composition(char *path, int len)
 {
 	static const char *auml_nfc = "\xc3\xa4";
 	static const char *auml_nfd = "\x61\xcc\x88";
-	size_t baselen = path->len;
+	struct strbuf sbuf;
 	int output_fd;
 	if (precomposed_unicode != -1)
 		return; /* We found it defined in the global config, respect it */
-	strbuf_addstr(path, auml_nfc);
-	output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
+	strbuf_init(&sbuf, len+3);
+	strbuf_add(&sbuf, path, len);
+	strbuf_addstr(&sbuf, auml_nfc);
+	output_fd = open(sbuf.buf, O_CREAT|O_EXCL|O_RDWR, 0600);
+	fprintf(stderr, "%s/%s:%d sbuf.buf=%s\n",
+					__FILE__, __FUNCTION__, __LINE__, sbuf.buf);
 	if (output_fd >= 0) {
 		close(output_fd);
-		strbuf_setlen(path, baselen);
-		strbuf_addstr(path, auml_nfd);
+		strbuf_setlen(&sbuf, len);
+		strbuf_addstr(&sbuf, auml_nfd);
+	fprintf(stderr, "%s/%s:%d sbuf.buf=%s\n",
+					__FILE__, __FUNCTION__, __LINE__, sbuf.buf);
 		precomposed_unicode = access(path, R_OK) ? 0 : 1;
 		git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
-		strbuf_setlen(path, baselen);
-		strbuf_addstr(path, auml_nfc);
+		strcpy(path + len, auml_nfc);
 		if (unlink(path))
 			die_errno(_("failed to unlink '%s'"), path);
 	}
-	strbuf_setlen(path, baselen);
+	strbuf_release(&sbuf);
 }
 
 
diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
index 7fc7be5..3b73585 100644
--- a/compat/precompose_utf8.h
+++ b/compat/precompose_utf8.h
@@ -27,7 +27,7 @@ typedef struct {
 } PREC_DIR;
 
 void precompose_argv(int argc, const char **argv);
-void probe_utf8_pathname_composition(struct strbuf *path);
+void probe_utf8_pathname_composition(char *, int);
 
 PREC_DIR *precompose_utf8_opendir(const char *dirname);
 struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);

Re: [PATCH 41/68] init: use strbufs to store paths

[Junio C Hamano]

Torsten Bögershausen <tboegi@web.de> writes:

> On 30.09.15 02:23, Jeff King wrote:
>> On Tue, Sep 29, 2015 at 04:50:39PM -0700, Michael Blume wrote:
>> 
>>> I see compile errors on my mac:
>>>
>
> This is my attempt, passing the test, but not fully polished.

Thanks.

> diff --git a/builtin/init-db.c b/builtin/init-db.c
> index 89f2c05..60b559c 100644
> --- a/builtin/init-db.c
> +++ b/builtin/init-db.c
> @@ -276,7 +276,9 @@ static int create_default_files(const char *template_path)
>  		path = git_path_buf(&buf, "CoNfIg");
>  		if (!access(path, F_OK))
>  			git_config_set("core.ignorecase", "true");
> -		probe_utf8_pathname_composition(path);
> +		/* Probe utf-8 normalization withou mangling CoNfIG */
> +		path = git_path_buf(&buf, "config");
> +		probe_utf8_pathname_composition(path, strlen(path));

Hmph, Peff's quick-fix passed the original "CoNfIg" in &buf directly
to probe_utf8_pathname_composition() without changing its signature.

What is the reason behind these two changes?  i.e. why is it
inappropriate to use "CoNfIg" (and append the auml to it to use for
the checking) and why does the function need to take pointer + len,
only to store it in another strbuf itself?

> diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
> index b4dd3c7..37172a4 100644
> --- a/compat/precompose_utf8.c
> +++ b/compat/precompose_utf8.c
> @@ -8,6 +8,7 @@
>  #include "cache.h"
>  #include "utf8.h"
>  #include "precompose_utf8.h"
> +#include "strbuf.h"
>  
>  typedef char *iconv_ibp;
>  static const char *repo_encoding = "UTF-8";
> @@ -36,28 +37,33 @@ static size_t has_non_ascii(const char *s, size_t maxlen, size_t *strlen_c)
>  }
>  
>  
> -void probe_utf8_pathname_composition(struct strbuf *path)
> +void probe_utf8_pathname_composition(char *path, int len)
>  {
>  	static const char *auml_nfc = "\xc3\xa4";
>  	static const char *auml_nfd = "\x61\xcc\x88";
> -	size_t baselen = path->len;
> +	struct strbuf sbuf;
>  	int output_fd;
>  	if (precomposed_unicode != -1)
>  		return; /* We found it defined in the global config, respect it */
> -	strbuf_addstr(path, auml_nfc);
> -	output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
> +	strbuf_init(&sbuf, len+3);
> +	strbuf_add(&sbuf, path, len);
> +	strbuf_addstr(&sbuf, auml_nfc);
> +	output_fd = open(sbuf.buf, O_CREAT|O_EXCL|O_RDWR, 0600);
> +	fprintf(stderr, "%s/%s:%d sbuf.buf=%s\n",
> +					__FILE__, __FUNCTION__, __LINE__, sbuf.buf);
>  	if (output_fd >= 0) {
>  		close(output_fd);
> -		strbuf_setlen(path, baselen);
> -		strbuf_addstr(path, auml_nfd);
> +		strbuf_setlen(&sbuf, len);
> +		strbuf_addstr(&sbuf, auml_nfd);
> +	fprintf(stderr, "%s/%s:%d sbuf.buf=%s\n",
> +					__FILE__, __FUNCTION__, __LINE__, sbuf.buf);
>  		precomposed_unicode = access(path, R_OK) ? 0 : 1;
>  		git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
> -		strbuf_setlen(path, baselen);
> -		strbuf_addstr(path, auml_nfc);
> +		strcpy(path + len, auml_nfc);
>  		if (unlink(path))
>  			die_errno(_("failed to unlink '%s'"), path);
>  	}
> -	strbuf_setlen(path, baselen);
> +	strbuf_release(&sbuf);
>  }
>  
>  
> diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
> index 7fc7be5..3b73585 100644
> --- a/compat/precompose_utf8.h
> +++ b/compat/precompose_utf8.h
> @@ -27,7 +27,7 @@ typedef struct {
>  } PREC_DIR;
>  
>  void precompose_argv(int argc, const char **argv);
> -void probe_utf8_pathname_composition(struct strbuf *path);
> +void probe_utf8_pathname_composition(char *, int);
>  
>  PREC_DIR *precompose_utf8_opendir(const char *dirname);
>  struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);

Re: [PATCH 41/68] init: use strbufs to store paths

[Torsten Bögershausen]

On 03.10.15 18:54, Junio C Hamano wrote:
> Torsten Bögershausen <tboegi@web.de> writes:
> 
>> On 30.09.15 02:23, Jeff King wrote:
>>> On Tue, Sep 29, 2015 at 04:50:39PM -0700, Michael Blume wrote:
>>>
>>>> I see compile errors on my mac:
>>>>
>>
>> This is my attempt, passing the test, but not fully polished.
> 
> Thanks.
> 
>> diff --git a/builtin/init-db.c b/builtin/init-db.c
>> index 89f2c05..60b559c 100644
>> --- a/builtin/init-db.c
>> +++ b/builtin/init-db.c
>> @@ -276,7 +276,9 @@ static int create_default_files(const char *template_path)
>>  		path = git_path_buf(&buf, "CoNfIg");
>>  		if (!access(path, F_OK))
>>  			git_config_set("core.ignorecase", "true");
>> -		probe_utf8_pathname_composition(path);
>> +		/* Probe utf-8 normalization withou mangling CoNfIG */
>> +		path = git_path_buf(&buf, "config");
>> +		probe_utf8_pathname_composition(path, strlen(path));
> 
> Hmph, Peff's quick-fix passed the original "CoNfIg" in &buf directly
> to probe_utf8_pathname_composition() without changing its signature.
True, ( I was thinking that the test did only work on case insensitive FS).
We can skip that change.

Beside that, I later realized, that a better signature could be:
+void probe_utf8_pathname_composition(const char *path, size_t len)

I can send a proper patch the next days.

Re: [PATCH 41/68] init: use strbufs to store paths

[Jeff King]

On Sat, Oct 03, 2015 at 11:12:13PM +0200, Torsten Bögershausen wrote:

> > Hmph, Peff's quick-fix passed the original "CoNfIg" in &buf directly
> > to probe_utf8_pathname_composition() without changing its signature.
> True, ( I was thinking that the test did only work on case insensitive FS).
> We can skip that change.
> 
> Beside that, I later realized, that a better signature could be:
> +void probe_utf8_pathname_composition(const char *path, size_t len)
> 
> I can send a proper patch the next days.

That is the original signature, before my sprintf series. I do not mind
leaving that as-is, and simply cleaning up probe_utf8_pathname_composition
by using a strbuf internally there. Though I have to wonder if it even
needs us to pass _anything_ at that point. It could just call
git_path_buf("config%s", auml_nfd) itself. The whole reason to pass
anything was to let it reuse the buffer the caller had.

-Peff

Re: [PATCH 41/68] init: use strbufs to store paths

[Torsten Bögershausen]

On 2015-10-04 05.37, Jeff King wrote:
> On Sat, Oct 03, 2015 at 11:12:13PM +0200, Torsten Bögershausen wrote:
>
>>> Hmph, Peff's quick-fix passed the original "CoNfIg" in &buf directly
>>> to probe_utf8_pathname_composition() without changing its signature.
>> True, ( I was thinking that the test did only work on case insensitive FS).
>> We can skip that change.
>>
>> Beside that, I later realized, that a better signature could be:
>> +void probe_utf8_pathname_composition(const char *path, size_t len)
>>
>> I can send a proper patch the next days.
> That is the original signature, before my sprintf series. I do not mind
> leaving that as-is, and simply cleaning up probe_utf8_pathname_composition
> by using a strbuf internally there. Though I have to wonder if it even
> needs us to pass _anything_ at that point. It could just call
> git_path_buf("config%s", auml_nfd) itself. The whole reason to pass
> anything was to let it reuse the buffer the caller had.
>
> -Peff
Makes sense, here is V2:
 git diff  07690109b6a252ac7cbede

diff --git a/builtin/init-db.c b/builtin/init-db.c
index 89f2c05..4892579 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -276,7 +276,7 @@ static int create_default_files(const char *template_path)
         path = git_path_buf(&buf, "CoNfIg");
         if (!access(path, F_OK))
             git_config_set("core.ignorecase", "true");
-        probe_utf8_pathname_composition(path);
+        probe_utf8_pathname_composition();
     }
 
     strbuf_release(&buf);
diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index b4dd3c7..64b85f2 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -8,6 +8,7 @@
 #include "cache.h"
 #include "utf8.h"
 #include "precompose_utf8.h"
+#include "strbuf.h"
 
 typedef char *iconv_ibp;
 static const char *repo_encoding = "UTF-8";
@@ -36,28 +37,27 @@ static size_t has_non_ascii(const char *s, size_t maxlen,
size_t *strlen_c)
 }
 
 
-void probe_utf8_pathname_composition(struct strbuf *path)
+void probe_utf8_pathname_composition(void)
 {
+    struct strbuf sbuf = STRBUF_INIT;
     static const char *auml_nfc = "\xc3\xa4";
     static const char *auml_nfd = "\x61\xcc\x88";
-    size_t baselen = path->len;
+    const char *path;
     int output_fd;
     if (precomposed_unicode != -1)
         return; /* We found it defined in the global config, respect it */
-    strbuf_addstr(path, auml_nfc);
+    path = git_path_buf(&sbuf, "%s", auml_nfc);
     output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
     if (output_fd >= 0) {
         close(output_fd);
-        strbuf_setlen(path, baselen);
-        strbuf_addstr(path, auml_nfd);
+        path = git_path_buf(&sbuf, "%s", auml_nfd);
         precomposed_unicode = access(path, R_OK) ? 0 : 1;
         git_config_set("core.precomposeunicode", precomposed_unicode ? "true" :
"false");
-        strbuf_setlen(path, baselen);
-        strbuf_addstr(path, auml_nfc);
+        path = git_path_buf(&sbuf, "%s", auml_nfc);
         if (unlink(path))
             die_errno(_("failed to unlink '%s'"), path);
     }
-    strbuf_setlen(path, baselen);
+    strbuf_release(&sbuf);
 }
 
 
diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
index 7fc7be5..a94e7c4 100644
--- a/compat/precompose_utf8.h
+++ b/compat/precompose_utf8.h
@@ -27,7 +27,7 @@ typedef struct {
 } PREC_DIR;
 
 void precompose_argv(int argc, const char **argv);
-void probe_utf8_pathname_composition(struct strbuf *path);
+void probe_utf8_pathname_composition(void);
 
 PREC_DIR *precompose_utf8_opendir(const char *dirname);
 struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);


============================

And this is fix for David:


diff --git a/refs.h b/refs.h
index f499093..7dee497 100644
--- a/refs.h
+++ b/refs.h
@@ -670,7 +670,6 @@ typedef int (*ref_transaction_verify_fn)(struct
ref_transaction *transaction,
         unsigned int flags, struct strbuf *err);
 typedef int (*ref_transaction_commit_fn)(struct ref_transaction *transaction,
                      struct strbuf *err);
-typedef void (*ref_transaction_free_fn)(struct ref_transaction *transaction);
 
 /* reflog functions */
 typedef int (*for_each_reflog_ent_fn)(const char *refname,

Re: [PATCH 41/68] init: use strbufs to store paths

[Jeff King]

On Sun, Oct 04, 2015 at 08:31:31AM +0200, Torsten Bögershausen wrote:

> > That is the original signature, before my sprintf series. I do not mind
> > leaving that as-is, and simply cleaning up probe_utf8_pathname_composition
> > by using a strbuf internally there. Though I have to wonder if it even
> > needs us to pass _anything_ at that point. It could just call
> > git_path_buf("config%s", auml_nfd) itself. The whole reason to pass
> > anything was to let it reuse the buffer the caller had.
> >
> > -Peff
> Makes sense, here is V2:

Yeah, I think this is much nicer.

And because it decouples the interface between init-db.c and the
precompose code, it is easy to do it as a separate patch before the
init-db one.

> diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
> index b4dd3c7..64b85f2 100644
> --- a/compat/precompose_utf8.c
> +++ b/compat/precompose_utf8.c
> @@ -8,6 +8,7 @@
>  #include "cache.h"
>  #include "utf8.h"
>  #include "precompose_utf8.h"
> +#include "strbuf.h"

I think this is actually redundant; it is part of cache.h included above
(and the precompose_utf8.h header file does not need to care anymore,
since the strbuf is not part of the interface).

> -void probe_utf8_pathname_composition(struct strbuf *path)
> +void probe_utf8_pathname_composition(void)
>  {
> +    struct strbuf sbuf = STRBUF_INIT;
>      static const char *auml_nfc = "\xc3\xa4";
>      static const char *auml_nfd = "\x61\xcc\x88";
> -    size_t baselen = path->len;
> +    const char *path;

I don't think we need this separate "path"; we can just access the
strbuf directly (that makes the diff a little noisier, but I think the
end result is simpler).

> diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
> index 7fc7be5..a94e7c4 100644
> --- a/compat/precompose_utf8.h
> +++ b/compat/precompose_utf8.h
> @@ -27,7 +27,7 @@ typedef struct {
>  } PREC_DIR;
>  
>  void precompose_argv(int argc, const char **argv);
> -void probe_utf8_pathname_composition(struct strbuf *path);
> +void probe_utf8_pathname_composition(void);

I think we need a similar fix for the compat macro to build on non-Mac
platforms.

Here's a mini-series I came up with, which I hope is polished enough for
Junio to apply as a drop-in replacement for the "init: use strbufs"
patch from my original series. I compiled-tested it on Linux, with and
without precompose_utf8.o support hacked in. I don't have access to an
OS X machine to test on, so I'd appreciate confirmation that t3910 still
passes there.

  [1/3]: precompose_utf8: drop unused variable
  [2/3]: probe_utf8_pathname_composition: use internal strbuf
  [3/3]: init: use strbufs to store paths

-Peff

[PATCH 1/3] precompose_utf8: drop unused variable

[Jeff King]

The result of iconv is assigned to a variable, but we never
use it (instead, we check errno and whether the function
consumed all bytes). Let's drop the assignment, as it
triggers gcc's -Wunused-but-set-variable.

Signed-off-by: Jeff King <peff@peff.net>
---
This is obviously completely optional; I just needed it to get the
"precompose on Linux" hack to build at all with my usual "-Wall -Werror"
settings. I guess clang doesn't have a similar warning, or maybe people
on Macs are not as pedantic as I am.

 compat/precompose_utf8.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index 95fe849..044c686 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -139,9 +139,8 @@ struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *prec_dir)
 				size_t inleft = namelenz;
 				char *outpos = &prec_dir->dirent_nfc->d_name[0];
 				size_t outsz = prec_dir->dirent_nfc->max_name_len;
-				size_t cnt;
 				errno = 0;
-				cnt = iconv(prec_dir->ic_precompose, &cp, &inleft, &outpos, &outsz);
+				iconv(prec_dir->ic_precompose, &cp, &inleft, &outpos, &outsz);
 				if (errno || inleft) {
 					/*
 					 * iconv() failed and errno could be E2BIG, EILSEQ, EINVAL, EBADF
-- 
2.6.0.455.ga3f9923

[PATCH 2/3] probe_utf8_pathname_composition: use internal strbuf

[Jeff King]

When we are initializing a .git directory, we may call
probe_utf8_pathname_composition to detect utf8 mangling. We
pass in a path buffer for it to use, and it blindly
strcpy()s into it, not knowing whether the buffer is large
enough to hold the result or not.

In practice this isn't a big deal, because the buffer we
pass in already contains "$GIT_DIR/config", and we append
only a few extra bytes to it. But we can easily do the right
thing just by calling git_path_buf ourselves. Technically
this results in a different pathname (before we appended our
utf8 characters to the "config" path, and now they get their
own files in $GIT_DIR), but that should not matter for our
purposes.

Signed-off-by: Jeff King <peff@peff.net>
---
I assume that "$GIT_DIR/$auml_nfc" is fine to perform this test based on
Torsten's patch showing the same simplification. If it matters, or if we
simply want to be ultra-conservative, changing the "%s" to "CoNfIg%s"
would yield identical behavior (but if it doesn't matter, I think I
prefer this as a simplification).

 builtin/init-db.c        |  2 +-
 compat/precompose_utf8.c | 18 ++++++++++--------
 compat/precompose_utf8.h |  2 +-
 git-compat-util.h        |  2 +-
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/builtin/init-db.c b/builtin/init-db.c
index e7d0e31..89addda 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -312,7 +312,7 @@ static int create_default_files(const char *template_path)
 		strcpy(path + len, "CoNfIg");
 		if (!access(path, F_OK))
 			git_config_set("core.ignorecase", "true");
-		probe_utf8_pathname_composition(path, len);
+		probe_utf8_pathname_composition();
 	}
 
 	return reinit;
diff --git a/compat/precompose_utf8.c b/compat/precompose_utf8.c
index 044c686..079070f 100644
--- a/compat/precompose_utf8.c
+++ b/compat/precompose_utf8.c
@@ -36,24 +36,26 @@ static size_t has_non_ascii(const char *s, size_t maxlen, size_t *strlen_c)
 }
 
 
-void probe_utf8_pathname_composition(char *path, int len)
+void probe_utf8_pathname_composition(void)
 {
+	struct strbuf path = STRBUF_INIT;
 	static const char *auml_nfc = "\xc3\xa4";
 	static const char *auml_nfd = "\x61\xcc\x88";
 	int output_fd;
 	if (precomposed_unicode != -1)
 		return; /* We found it defined in the global config, respect it */
-	strcpy(path + len, auml_nfc);
-	output_fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600);
+	git_path_buf(&path, "%s", auml_nfc);
+	output_fd = open(path.buf, O_CREAT|O_EXCL|O_RDWR, 0600);
 	if (output_fd >= 0) {
 		close(output_fd);
-		strcpy(path + len, auml_nfd);
-		precomposed_unicode = access(path, R_OK) ? 0 : 1;
+		git_path_buf(&path, "%s", auml_nfd);
+		precomposed_unicode = access(path.buf, R_OK) ? 0 : 1;
 		git_config_set("core.precomposeunicode", precomposed_unicode ? "true" : "false");
-		strcpy(path + len, auml_nfc);
-		if (unlink(path))
-			die_errno(_("failed to unlink '%s'"), path);
+		git_path_buf(&path, "%s", auml_nfc);
+		if (unlink(path.buf))
+			die_errno(_("failed to unlink '%s'"), path.buf);
 	}
+	strbuf_release(&path);
 }
 
 
diff --git a/compat/precompose_utf8.h b/compat/precompose_utf8.h
index 3b73585..a94e7c4 100644
--- a/compat/precompose_utf8.h
+++ b/compat/precompose_utf8.h
@@ -27,7 +27,7 @@ typedef struct {
 } PREC_DIR;
 
 void precompose_argv(int argc, const char **argv);
-void probe_utf8_pathname_composition(char *, int);
+void probe_utf8_pathname_composition(void);
 
 PREC_DIR *precompose_utf8_opendir(const char *dirname);
 struct dirent_prec_psx *precompose_utf8_readdir(PREC_DIR *dirp);
diff --git a/git-compat-util.h b/git-compat-util.h
index 348b9dc..9a3e559 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -229,7 +229,7 @@ typedef unsigned long uintptr_t;
 #else
 #define precompose_str(in,i_nfd2nfc)
 #define precompose_argv(c,v)
-#define probe_utf8_pathname_composition(a,b)
+#define probe_utf8_pathname_composition()
 #endif
 
 #ifdef MKDIR_WO_TRAILING_SLASH
-- 
2.6.0.455.ga3f9923

[PATCH 3/3] init: use strbufs to store paths

[Jeff King]

The init code predates strbufs, and uses PATH_MAX-sized
buffers along with many manual checks on intermediate sizes
(some of which make magic assumptions, such as that init
will not create a path inside .git longer than 50
characters).

We can simplify this greatly by using strbufs, which drops
some hard-to-verify strcpy calls in favor of git_path_buf.
While we're in the area, let's also convert existing calls
to git_path to the safer git_path_buf (our existing calls
were passed to pretty tame functions, and so were not a
problem, but it's easy to be consistent and safe here).

Note that we had an explicit test that "git init" rejects
long template directories. This comes from 32d1776 (init: Do
not segfault on big GIT_TEMPLATE_DIR environment variable,
2009-04-18). We can drop the test_must_fail here, as we now
accept this and need only confirm that we don't segfault,
which was the original point of the test.

Signed-off-by: Jeff King <peff@peff.net>
---
Same as the original, but minus the bits that touch the precompose
probing.

 builtin/init-db.c | 172 +++++++++++++++++++++++-------------------------------
 t/t0001-init.sh   |   4 +-
 2 files changed, 76 insertions(+), 100 deletions(-)

diff --git a/builtin/init-db.c b/builtin/init-db.c
index 89addda..f59f407 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -36,10 +36,11 @@ static void safe_create_dir(const char *dir, int share)
 		die(_("Could not make %s writable by group"), dir);
 }
 
-static void copy_templates_1(char *path, int baselen,
-			     char *template, int template_baselen,
+static void copy_templates_1(struct strbuf *path, struct strbuf *template,
 			     DIR *dir)
 {
+	size_t path_baselen = path->len;
+	size_t template_baselen = template->len;
 	struct dirent *de;
 
 	/* Note: if ".git/hooks" file exists in the repository being
@@ -49,77 +50,64 @@ static void copy_templates_1(char *path, int baselen,
 	 * with the way the namespace under .git/ is organized, should
 	 * be really carefully chosen.
 	 */
-	safe_create_dir(path, 1);
+	safe_create_dir(path->buf, 1);
 	while ((de = readdir(dir)) != NULL) {
 		struct stat st_git, st_template;
-		int namelen;
 		int exists = 0;
 
+		strbuf_setlen(path, path_baselen);
+		strbuf_setlen(template, template_baselen);
+
 		if (de->d_name[0] == '.')
 			continue;
-		namelen = strlen(de->d_name);
-		if ((PATH_MAX <= baselen + namelen) ||
-		    (PATH_MAX <= template_baselen + namelen))
-			die(_("insanely long template name %s"), de->d_name);
-		memcpy(path + baselen, de->d_name, namelen+1);
-		memcpy(template + template_baselen, de->d_name, namelen+1);
-		if (lstat(path, &st_git)) {
+		strbuf_addstr(path, de->d_name);
+		strbuf_addstr(template, de->d_name);
+		if (lstat(path->buf, &st_git)) {
 			if (errno != ENOENT)
-				die_errno(_("cannot stat '%s'"), path);
+				die_errno(_("cannot stat '%s'"), path->buf);
 		}
 		else
 			exists = 1;
 
-		if (lstat(template, &st_template))
-			die_errno(_("cannot stat template '%s'"), template);
+		if (lstat(template->buf, &st_template))
+			die_errno(_("cannot stat template '%s'"), template->buf);
 
 		if (S_ISDIR(st_template.st_mode)) {
-			DIR *subdir = opendir(template);
-			int baselen_sub = baselen + namelen;
-			int template_baselen_sub = template_baselen + namelen;
+			DIR *subdir = opendir(template->buf);
 			if (!subdir)
-				die_errno(_("cannot opendir '%s'"), template);
-			path[baselen_sub++] =
-				template[template_baselen_sub++] = '/';
-			path[baselen_sub] =
-				template[template_baselen_sub] = 0;
-			copy_templates_1(path, baselen_sub,
-					 template, template_baselen_sub,
-					 subdir);
+				die_errno(_("cannot opendir '%s'"), template->buf);
+			strbuf_addch(path, '/');
+			strbuf_addch(template, '/');
+			copy_templates_1(path, template, subdir);
 			closedir(subdir);
 		}
 		else if (exists)
 			continue;
 		else if (S_ISLNK(st_template.st_mode)) {
-			char lnk[256];
-			int len;
-			len = readlink(template, lnk, sizeof(lnk));
-			if (len < 0)
-				die_errno(_("cannot readlink '%s'"), template);
-			if (sizeof(lnk) <= len)
-				die(_("insanely long symlink %s"), template);
-			lnk[len] = 0;
-			if (symlink(lnk, path))
-				die_errno(_("cannot symlink '%s' '%s'"), lnk, path);
+			struct strbuf lnk = STRBUF_INIT;
+			if (strbuf_readlink(&lnk, template->buf, 0) < 0)
+				die_errno(_("cannot readlink '%s'"), template->buf);
+			if (symlink(lnk.buf, path->buf))
+				die_errno(_("cannot symlink '%s' '%s'"),
+					  lnk.buf, path->buf);
+			strbuf_release(&lnk);
 		}
 		else if (S_ISREG(st_template.st_mode)) {
-			if (copy_file(path, template, st_template.st_mode))
-				die_errno(_("cannot copy '%s' to '%s'"), template,
-					  path);
+			if (copy_file(path->buf, template->buf, st_template.st_mode))
+				die_errno(_("cannot copy '%s' to '%s'"),
+					  template->buf, path->buf);
 		}
 		else
-			error(_("ignoring template %s"), template);
+			error(_("ignoring template %s"), template->buf);
 	}
 }
 
 static void copy_templates(const char *template_dir)
 {
-	char path[PATH_MAX];
-	char template_path[PATH_MAX];
-	int template_len;
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf template_path = STRBUF_INIT;
+	size_t template_len;
 	DIR *dir;
-	const char *git_dir = get_git_dir();
-	int len = strlen(git_dir);
 	char *to_free = NULL;
 
 	if (!template_dir)
@@ -132,26 +120,23 @@ static void copy_templates(const char *template_dir)
 		free(to_free);
 		return;
 	}
-	template_len = strlen(template_dir);
-	if (PATH_MAX <= (template_len+strlen("/config")))
-		die(_("insanely long template path %s"), template_dir);
-	strcpy(template_path, template_dir);
-	if (template_path[template_len-1] != '/') {
-		template_path[template_len++] = '/';
-		template_path[template_len] = 0;
-	}
-	dir = opendir(template_path);
+
+	strbuf_addstr(&template_path, template_dir);
+	strbuf_complete(&template_path, '/');
+	template_len = template_path.len;
+
+	dir = opendir(template_path.buf);
 	if (!dir) {
 		warning(_("templates not found %s"), template_dir);
 		goto free_return;
 	}
 
 	/* Make sure that template is from the correct vintage */
-	strcpy(template_path + template_len, "config");
+	strbuf_addstr(&template_path, "config");
 	repository_format_version = 0;
 	git_config_from_file(check_repository_format_version,
-			     template_path, NULL);
-	template_path[template_len] = 0;
+			     template_path.buf, NULL);
+	strbuf_setlen(&template_path, template_len);
 
 	if (repository_format_version &&
 	    repository_format_version != GIT_REPO_VERSION) {
@@ -162,17 +147,15 @@ static void copy_templates(const char *template_dir)
 		goto close_free_return;
 	}
 
-	memcpy(path, git_dir, len);
-	if (len && path[len - 1] != '/')
-		path[len++] = '/';
-	path[len] = 0;
-	copy_templates_1(path, len,
-			 template_path, template_len,
-			 dir);
+	strbuf_addstr(&path, get_git_dir());
+	strbuf_complete(&path, '/');
+	copy_templates_1(&path, &template_path, dir);
 close_free_return:
 	closedir(dir);
 free_return:
 	free(to_free);
+	strbuf_release(&path);
+	strbuf_release(&template_path);
 }
 
 static int git_init_db_config(const char *k, const char *v, void *cb)
@@ -199,28 +182,20 @@ static int needs_work_tree_config(const char *git_dir, const char *work_tree)
 
 static int create_default_files(const char *template_path)
 {
-	const char *git_dir = get_git_dir();
-	unsigned len = strlen(git_dir);
-	static char path[PATH_MAX];
 	struct stat st1;
+	struct strbuf buf = STRBUF_INIT;
+	char *path;
 	char repo_version_string[10];
 	char junk[2];
 	int reinit;
 	int filemode;
 
-	if (len > sizeof(path)-50)
-		die(_("insane git directory %s"), git_dir);
-	memcpy(path, git_dir, len);
-
-	if (len && path[len-1] != '/')
-		path[len++] = '/';
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs"), 1);
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs/heads"), 1);
+	safe_create_dir(git_path_buf(&buf, "refs/tags"), 1);
 
 	/* Just look for `init.templatedir` */
 	git_config(git_init_db_config, NULL);
@@ -244,16 +219,16 @@ static int create_default_files(const char *template_path)
 	 */
 	if (shared_repository) {
 		adjust_shared_perm(get_git_dir());
-		adjust_shared_perm(git_path("refs"));
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		adjust_shared_perm(git_path_buf(&buf, "refs"));
+		adjust_shared_perm(git_path_buf(&buf, "refs/heads"));
+		adjust_shared_perm(git_path_buf(&buf, "refs/tags"));
 	}
 
 	/*
 	 * Create the default symlink from ".git/HEAD" to the "master"
 	 * branch, if it does not exist yet.
 	 */
-	strcpy(path + len, "HEAD");
+	path = git_path_buf(&buf, "HEAD");
 	reinit = (!access(path, R_OK)
 		  || readlink(path, junk, sizeof(junk)-1) != -1);
 	if (!reinit) {
@@ -266,10 +241,8 @@ static int create_default_files(const char *template_path)
 		  "%d", GIT_REPO_VERSION);
 	git_config_set("core.repositoryformatversion", repo_version_string);
 
-	path[len] = 0;
-	strcpy(path + len, "config");
-
 	/* Check filemode trustability */
+	path = git_path_buf(&buf, "config");
 	filemode = TEST_FILEMODE;
 	if (TEST_FILEMODE && !lstat(path, &st1)) {
 		struct stat st2;
@@ -290,14 +263,13 @@ static int create_default_files(const char *template_path)
 		/* allow template config file to override the default */
 		if (log_all_ref_updates == -1)
 		    git_config_set("core.logallrefupdates", "true");
-		if (needs_work_tree_config(git_dir, work_tree))
+		if (needs_work_tree_config(get_git_dir(), work_tree))
 			git_config_set("core.worktree", work_tree);
 	}
 
 	if (!reinit) {
 		/* Check if symlink is supported in the work tree */
-		path[len] = 0;
-		strcpy(path + len, "tXXXXXX");
+		path = git_path_buf(&buf, "tXXXXXX");
 		if (!close(xmkstemp(path)) &&
 		    !unlink(path) &&
 		    !symlink("testing", path) &&
@@ -308,31 +280,35 @@ static int create_default_files(const char *template_path)
 			git_config_set("core.symlinks", "false");
 
 		/* Check if the filesystem is case-insensitive */
-		path[len] = 0;
-		strcpy(path + len, "CoNfIg");
+		path = git_path_buf(&buf, "CoNfIg");
 		if (!access(path, F_OK))
 			git_config_set("core.ignorecase", "true");
 		probe_utf8_pathname_composition();
 	}
 
+	strbuf_release(&buf);
 	return reinit;
 }
 
 static void create_object_directory(void)
 {
-	const char *object_directory = get_object_directory();
-	int len = strlen(object_directory);
-	char *path = xmalloc(len + 40);
+	struct strbuf path = STRBUF_INIT;
+	size_t baselen;
+
+	strbuf_addstr(&path, get_object_directory());
+	baselen = path.len;
+
+	safe_create_dir(path.buf, 1);
 
-	memcpy(path, object_directory, len);
+	strbuf_setlen(&path, baselen);
+	strbuf_addstr(&path, "/pack");
+	safe_create_dir(path.buf, 1);
 
-	safe_create_dir(object_directory, 1);
-	strcpy(path+len, "/pack");
-	safe_create_dir(path, 1);
-	strcpy(path+len, "/info");
-	safe_create_dir(path, 1);
+	strbuf_setlen(&path, baselen);
+	strbuf_addstr(&path, "/info");
+	safe_create_dir(path.buf, 1);
 
-	free(path);
+	strbuf_release(&path);
 }
 
 int set_git_dir_init(const char *git_dir, const char *real_git_dir,
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 7de8d85..f91bbcf 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -202,8 +202,8 @@ test_expect_success 'init honors global core.sharedRepository' '
 	x$(git config -f shared-honor-global/.git/config core.sharedRepository)
 '
 
-test_expect_success 'init rejects insanely long --template' '
-	test_must_fail git init --template=$(printf "x%09999dx" 1) test
+test_expect_success 'init allows insanely long --template' '
+	git init --template=$(printf "x%09999dx" 1) test
 '
 
 test_expect_success 'init creates a new directory' '
-- 
2.6.0.455.ga3f9923

Re: [PATCH 1/3] precompose_utf8: drop unused variable

[Torsten Bögershausen]

On 2015-10-05 05.43, Jeff King wrote:
[]
The whole series looks good, cleans up my mess and passes t3910.
Thanks for that.