From: Jon Seymour <jon.seymour@gmail.com>
To: Git Mailing List <git@vger.kernel.org>
Subject: [PATCH] Add -i option to cat-file to allow operation on displaced git object files
Date: Sun, 24 Apr 2005 04:27:01 +1000 [thread overview]
Message-ID: <2cfc403205042311272baee82e@mail.gmail.com> (raw)
For the purposes of merging the contents of remote git object
repositories at the filesystem level, it would be helpful to be able
to verify the integrity of a remote git object file before it is
actually copied into the local repository.
To enable this, the option syntax for the usage of the cat-file tool
is extended with a -i option, per the modified usage string quoted
below:
usage: cat-file [-t | tagname] <sha1> [ -i displaced-git-object-file ]
If the -i option is specified, cat-file uses the filename specified on
the command line rather than the derived filename to locate and
process the git object file implied by the sha1 argument.
In addition, the -i option forces cat-file to check the SHA1 signature
of the specified input file against the SHA1 signature specified on
the command line and report an error if there is a mismatch.
Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
--
Index: cache.h
===================================================================
--- e6d3a81c30ad237102e2ca82f3dfc57d0b9f0ddf/cache.h (mode:100644
sha1:bf30ac4741d2eeeb483079f566182505898082f3)
+++ 1b503f0571727a865b413e28641d2be09c8c3304/cache.h (mode:100644
sha1:56eacfa0ab43c93a838efedca429e865c95f16bc)
@@ -121,8 +121,9 @@
extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
extern void * unpack_sha1_file(void *map, unsigned long mapsize,
char *type, unsigned long *size);
extern void * read_sha1_file(const unsigned char *sha1, char *type,
unsigned long *size);
+extern void * read_displaced_sha1_file(char *type, unsigned long
*size, const char *filename);
extern int write_sha1_file(char *buf, unsigned len, unsigned char
*return_sha1);
-extern int check_sha1_signature(unsigned char *sha1, void *buf,
unsigned long size, const char *type);
+extern int check_sha1_signature(const unsigned char *sha1, void *buf,
unsigned long size, const char *type);
/* Read a tree into the cache */
extern int read_tree(void *buffer, unsigned long size, int stage);
Index: cat-file.c
===================================================================
--- e6d3a81c30ad237102e2ca82f3dfc57d0b9f0ddf/cat-file.c (mode:100644
sha1:3c47d79a16305d326a65768fe9f37ee25928510b)
+++ 1b503f0571727a865b413e28641d2be09c8c3304/cat-file.c (mode:100644
sha1:c88df7287b6ce7d6d33d016ffb524cc5a793cad2)
@@ -5,16 +5,32 @@
*/
#include "cache.h"
+static char _usage[]="cat-file [-t | tagname] <sha1> [ -i
displaced-git-object-file ]";
+
int main(int argc, char **argv)
{
unsigned char sha1[20];
char type[20];
- void *buf;
+ void *buf = NULL;
unsigned long size;
- if (argc != 3 || get_sha1_hex(argv[2], sha1))
- usage("cat-file [-t | tagname] <sha1>");
- buf = read_sha1_file(sha1, type, &size);
+ if (argc < 3 || get_sha1_hex(argv[2], sha1))
+ usage(_usage);
+
+ if (argc == 3) {
+ buf = read_sha1_file(sha1, type, &size);
+ } else if (argc == 5 && !strcmp(argv[3], "-i")) {
+ buf = read_displaced_sha1_file(type, &size, argv[4]);
+ if (!buf)
+ die("bad file: %s", argv[4]);
+
+ if (check_sha1_signature(sha1, buf, size, type) < 0)
+ die("signature mismatch for %s", argv[4]);
+
+ } else {
+ usage(_usage);
+ }
+
if (!buf)
die("cat-file %s: bad file", argv[2]);
if (!strcmp("-t", argv[1])) {
Index: sha1_file.c
===================================================================
--- e6d3a81c30ad237102e2ca82f3dfc57d0b9f0ddf/sha1_file.c (mode:100644
sha1:6f7228e106d4e24b18f8416cc6adc2a6fd303eb7)
+++ 1b503f0571727a865b413e28641d2be09c8c3304/sha1_file.c (mode:100644
sha1:25e2e8b22cf9590a6df05f234ce88db8c2cd1030)
@@ -80,7 +80,7 @@
return base;
}
-int check_sha1_signature(unsigned char *sha1, void *map, unsigned
long size, const char *type)
+int check_sha1_signature(const unsigned char *sha1, void *map,
unsigned long size, const char *type)
{
char header[100];
unsigned char real_sha1[20];
@@ -93,13 +93,12 @@
return memcmp(sha1, real_sha1, 20) ? -1 : 0;
}
-void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+static void *map_file(const char *filename, unsigned long *size)
{
- char *filename = sha1_file_name(sha1);
- int fd = open(filename, O_RDONLY);
struct stat st;
void *map;
+ int fd = open(filename, O_RDONLY);
if (fd < 0) {
perror(filename);
return NULL;
@@ -116,6 +115,12 @@
return map;
}
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+{
+ char *filename = sha1_file_name(sha1);
+ return map_file(filename, size);
+}
+
void * unpack_sha1_file(void *map, unsigned long mapsize, char
*type, unsigned long *size)
{
int ret, bytes;
@@ -166,6 +171,20 @@
return NULL;
}
+void * read_displaced_sha1_file(char *type, unsigned long *size,
const char *filename)
+{
+ unsigned long mapsize;
+ void *map, *buf;
+
+ map = map_file(filename, &mapsize);
+ if (map) {
+ buf = unpack_sha1_file(map, mapsize, type, size);
+ munmap(map, mapsize);
+ return buf;
+ }
+ return NULL;
+}
+
void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
unsigned long *size,
unsigned char *tree_sha1_return)
next reply other threads:[~2005-04-23 18:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-23 18:27 Jon Seymour [this message]
2005-04-23 18:48 ` [resend] [PATCH] Add -i option to cat-file to allow operation on displaced git object files Jon Seymour
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