[PATCH] gc: use temporary file for editing crontab
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- Aug 23, 2022, 01:01 UTC
- Message-ID
- <20220823010120.25388-1-sandals@crustytoothpaste.net>
- In-Reply-To
- <1dd29f43-1a8e-eb69-3320-7f5140a0e18e@github.com>
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.
Reported-by: Renato Botelho <garga@FreeBSD.org> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> --- My apologies for the delay on this. I forgot when I'd send a patch that I had a wedding out of town.
builtin/gc.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-)
diff --git a/builtin/gc.c b/builtin/gc.c index eeff2b760e..168dbdb5d9 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; get_schedule_cmd(&cmd, NULL); strvec_split(&crontab_list.args, cmd); @@ -2079,6 +2080,15 @@ 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) + return error(_("failed to create crontab temporary file")); + 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 +2096,6 @@ 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 +2129,22 @@ 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: + close_tempfile_gently(tmpedit); return result; }