Since ee69e7884e (gc: use temporary file for editing crontab,
2022-08-28), we now insist that "argc == 3" (and otherwise return an
error). Coverity notes that this causes some dead code:
if (argc == 3)
fclose(from);
else
fclose(to);
as we will never trigger the else. This also causes a memory leak, since
we'll never close "to".
Now that all paths require 2 arguments, we can just reorganize the
function to check argc up front, and tweak the cleanup to do the right
thing for all cases.
While we're here, we can also notice some minor problems:
- we return a negative int via error() from what is essentially a
main() function; we should return a positive non-zero value for
error. Or better yet, we can just use usage(), which gives a better
message.
- while writing the usage message, we can note the one in the comment
was made out of date by ee69e7884e. But it also had a typo already,
calling the subcommand "cron" and not "crontab"
- we didn't check for an error from fopen(), meaning we would segfault
if the to-be-read file was missing. We can use xfopen() to catch
this.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While cron is specified by POSIX, there are a wide variety of
implementations in use. "git maintenance" assumes that the
"crontab" command can be fed from its standard input the new
contents and the syntax to do so is not to have any filename
argument, as POSIX describes. However, on FreeBSD, the cron
implementation requires a file name argument: if the user wants to
edit standard input, they must specify "-".
Unfortunately, POSIX systems do not have to interpret "-" on the
command line of crontab as a request to read from the standard
input. Blindly adding "-" on the command line would not work as a
general solution.
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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add new subcommands to 'git maintenance' that start or stop background
maintenance using 'cron', when available. This integration is as simple
as I could make it, barring some implementation complications.
The schedule is laid out as follows:
0 1-23 * * * $cmd maintenance run --schedule=hourly
0 0 * * 1-6 $cmd maintenance run --schedule=daily
0 0 * * 0 $cmd maintenance run --schedule=weekly
where $cmd is a properly-qualified 'git for-each-repo' execution:
$cmd=$path/git --exec-path=$path for-each-repo --config=maintenance.repo
where $path points to the location of the Git executable running 'git
maintenance start'. This is critical for systems with multiple versions
of Git. Specifically, macOS has a system version at '/usr/bin/git' while
the version that users can install resides at '/usr/local/bin/git'
(symlinked to '/usr/local/libexec/git-core/git'). This will also use
your locally-built version if you build and run this in your development
environment without installing first.
This conditional schedule avoids having cron launch multiple 'git
for-each-repo' commands in parallel. Such parallel commands would likely
lead to the 'hourly' and 'daily' tasks competing over the object
database lock. This could lead to to some tasks never being run! Since
the --schedule=<frequency> argument will run all tasks with _at least_
the given frequency, the daily runs will also run the hourly tasks.
Similarly, the weekly runs will also run the daily and hourly tasks.
The GIT_TEST_CRONTAB environment variable is not intended for users to
edit, but instead as a way to mock the 'crontab [-l]' command. This
variable is set in test-lib.sh to avoid a future test from accidentally
running anything with the cron integration from modifying the user's
schedule. We use GIT_TEST_CRONTAB='test-tool crontab <file>' in our
tests to check how the schedule is modified in 'git maintenance
(start|stop)' commands.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
