From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: <git@vger.kernel.org>
Cc: Junio C Hamano <gitster@pobox.com>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Derrick Stolee <stolee@gmail.com>,
Renato Botelho <garga@FreeBSD.org>
Subject: [PATCH v2] gc: use temporary file for editing crontab
Date: Sun, 28 Aug 2022 21:41:43 +0000 [thread overview]
Message-ID: <20220828214143.754759-1-sandals@crustytoothpaste.net> (raw)
In-Reply-To: <20220823010120.25388-1-sandals@crustytoothpaste.net>
While cron is specified by POSIX, there are a wide variety of
implementations in use. On FreeBSD, the cron implementation requires a
file name argument: if the user wants to edit standard input, they must
specify "-". However, this notation is not specified by POSIX, allowing
the possibility that making such a change may break other, less common
implementations.
Since POSIX tells us that cron must accept a file name argument, let's
solve this problem by specifying a temporary file instead. This will
ensure that we work with the vast majority of implementations.
Note that because delete_tempfile closes the file for us, we should not
call fclose here on the handle, since doing so will introduce a double
free.
Reported-by: Renato Botelho <garga@FreeBSD.org>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
Changes from v1:
* Use `goto out;` in additional places.
* Fix broken test.
* Use `delete_tempfile`.
* Improve commit message to mention `fclose` rationale.
builtin/gc.c | 39 +++++++++++++++++++++++----------------
t/helper/test-crontab.c | 4 ++--
2 files changed, 25 insertions(+), 18 deletions(-)
diff --git a/builtin/gc.c b/builtin/gc.c
index eeff2b760e..0d9e6dabef 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -2065,6 +2065,7 @@ static int crontab_update_schedule(int run_maintenance, int fd)
struct child_process crontab_edit = CHILD_PROCESS_INIT;
FILE *cron_list, *cron_in;
struct strbuf line = STRBUF_INIT;
+ struct tempfile *tmpedit = NULL;
get_schedule_cmd(&cmd, NULL);
strvec_split(&crontab_list.args, cmd);
@@ -2079,6 +2080,17 @@ static int crontab_update_schedule(int run_maintenance, int fd)
/* Ignore exit code, as an empty crontab will return error. */
finish_command(&crontab_list);
+ tmpedit = mks_tempfile_t(".git_cron_edit_tmpXXXXXX");
+ if (!tmpedit) {
+ result = error(_("failed to create crontab temporary file"));
+ goto out;
+ }
+ cron_in = fdopen_tempfile(tmpedit, "w");
+ if (!cron_in) {
+ result = error(_("failed to open temporary file"));
+ goto out;
+ }
+
/*
* Read from the .lock file, filtering out the old
* schedule while appending the new schedule.
@@ -2086,19 +2098,6 @@ static int crontab_update_schedule(int run_maintenance, int fd)
cron_list = fdopen(fd, "r");
rewind(cron_list);
- strvec_split(&crontab_edit.args, cmd);
- crontab_edit.in = -1;
- crontab_edit.git_cmd = 0;
-
- if (start_command(&crontab_edit))
- return error(_("failed to run 'crontab'; your system might not support 'cron'"));
-
- cron_in = fdopen(crontab_edit.in, "w");
- if (!cron_in) {
- result = error(_("failed to open stdin of 'crontab'"));
- goto done_editing;
- }
-
while (!strbuf_getline_lf(&line, cron_list)) {
if (!in_old_region && !strcmp(line.buf, BEGIN_LINE))
in_old_region = 1;
@@ -2132,14 +2131,22 @@ static int crontab_update_schedule(int run_maintenance, int fd)
}
fflush(cron_in);
- fclose(cron_in);
- close(crontab_edit.in);
-done_editing:
+ strvec_split(&crontab_edit.args, cmd);
+ strvec_push(&crontab_edit.args, get_tempfile_path(tmpedit));
+ crontab_edit.git_cmd = 0;
+
+ if (start_command(&crontab_edit)) {
+ result = error(_("failed to run 'crontab'; your system might not support 'cron'"));
+ goto out;
+ }
+
if (finish_command(&crontab_edit))
result = error(_("'crontab' died"));
else
fclose(cron_list);
+out:
+ delete_tempfile(&tmpedit);
return result;
}
diff --git a/t/helper/test-crontab.c b/t/helper/test-crontab.c
index e7c0137a47..2942543046 100644
--- a/t/helper/test-crontab.c
+++ b/t/helper/test-crontab.c
@@ -17,8 +17,8 @@ int cmd__crontab(int argc, const char **argv)
if (!from)
return 0;
to = stdout;
- } else if (argc == 2) {
- from = stdin;
+ } else if (argc == 3) {
+ from = fopen(argv[2], "r");
to = fopen(argv[1], "w");
} else
return error("unknown arguments");
next prev parent reply other threads:[~2022-08-28 21:42 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 13:51 git maintenance broken on FreeBSD Renato Botelho
2022-08-12 14:44 ` Đoàn Trần Công Danh
2022-08-13 3:42 ` Todd Zullinger
2022-08-13 5:02 ` Junio C Hamano
2022-08-13 15:37 ` Đoàn Trần Công Danh
2022-08-13 17:26 ` Junio C Hamano
2022-08-13 17:35 ` brian m. carlson
2022-08-15 13:22 ` Derrick Stolee
2022-08-15 16:09 ` Junio C Hamano
2022-08-23 1:01 ` [PATCH] gc: use temporary file for editing crontab brian m. carlson
2022-08-23 9:12 ` Johannes Schindelin
2022-08-23 17:06 ` Derrick Stolee
2022-08-23 21:15 ` brian m. carlson
2022-08-24 16:06 ` Junio C Hamano
2022-08-28 21:41 ` brian m. carlson [this message]
2022-08-29 6:46 ` [PATCH v2] " Junio C Hamano
2022-08-29 10:52 ` Renato Botelho
2022-08-30 13:27 ` Derrick Stolee
2022-08-30 20:40 ` [PATCH] test-crontab: minor memory and error handling fixes Jeff King
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