Re: [PATCH] receive-pack: plug minor memory leak in unpack()

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 13, 2014, 19:08 UTC
Message-ID: <xmqq1tqb4wkm.fsf@gitster.dls.corp.google.com>
In-Reply-To: <20141012015321.GA15272@peff.net>

Jeff King <peff@peff.net> writes:

Show 8 quoted lines

> On Sat, Oct 11, 2014 at 01:00:16PM +0200, René Scharfe wrote:
>
>> The argv_array used in unpack() is never freed.  Instead of adding
>> explicit calls to argv_array_clear() use the args member of struct
>> child_process and let run_command() and friends clean up for us.
>
> Looks good. I notice that the recently added prepare_push_cert_sha1 uses
> an argv_array to create the child_process.env, and we leak the result.

You're right. finish_command() runs argv_array_clear() on cmd->args, but does not care about cmd->env so anybody that use the (optional) "use these environment variable settings while running the command" would leak unless the caller takes care of it.

> I wonder if run-command should provide a managed env array similar
> to the "args" array.

I took a look at a few of them:

 - setup_pager() uses a static set of environment variables that are
   not built with argv_array(); should be easy to convert, though.

 - wt_status_print_submodule_summary() does use two argv_arrays, for
   env and argv.  It can use the managed "args" today, and with such
   a change it can also use the managed "envs".

 - receive-pack.c::prepare_push_cert_sha1() would benefit from
   managed "envs".

 - http-backend.c::run_service() would benefit from managed "envs".

 - daemon.c::handle() uses a static set of environment variables
   that are not built with argv_array().  Same for argv.

It shouldn't be too hard to catch and convert all of them.