Re: [PATCH 14/23] builtin/repack: fix leaking configuration

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 20, 2024, 17:28 UTC
Message-ID: <xmqqr09e2q0m.fsf@gitster.g>
In-Reply-To: <a5f3931eee1e49c60e1d5be214263aeaf3d5c65f.1726484308.git.ps@pks.im>

Patrick Steinhardt <ps@pks.im> writes:

Show 27 quoted lines

> When repacking, we assemble git-pack-objects(1) arguments both for the
> "normal" pack and for the cruft pack. This configuration gets populated
> with a bunch of `OPT_PASSTHRU` options that we end up passing to the
> child process. These options are allocated, but never free'd.
>
> Create a new `pack_objects_args_release()` function that releases the
> memory for us and call it for both sets of options.
>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  builtin/repack.c              | 57 ++++++++++++++++++++++++++---------
>  t/t5329-pack-objects-cruft.sh |  2 ++
>  t/t7700-repack.sh             |  1 +
>  3 files changed, 45 insertions(+), 15 deletions(-)
>
> diff --git a/builtin/repack.c b/builtin/repack.c
> index 3ee8cfa732f..c31d5653f1f 100644
> --- a/builtin/repack.c
> +++ b/builtin/repack.c
> @@ -85,17 +85,34 @@ static int repack_config(const char *var, const char *value,
>  		run_update_server_info = git_config_bool(var, value);
>  		return 0;
>  	}
> -	if (!strcmp(var, "repack.cruftwindow"))
> +	if (!strcmp(var, "repack.cruftwindow")) {
> +		free(cruft_po_args->window);
>  		return git_config_string(&cruft_po_args->window, var, value);

Surely, as git_config_string() gives an allocated string, the ownership rules should be that the receiving variable/struct member is responsible for properly freeing it, which means that the current value must be discarded before the new value is taken. Looking good.

I wonder if any of these targets (like the cruft_po_args->window we see here) can be updated by parsing the command line arguments (with OPT_STRING)? It turns out that this worry is not unfounded but you already covered it ...

>  		if (!cruft_po_args.window)
> -			cruft_po_args.window = po_args.window;
> +			cruft_po_args.window = xstrdup_or_null(po_args.window);

... here, so we are safe.

Looking good.

Thanks.