From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 01/12] for_each_alternate_ref: handle failure from real_pathdup()
Date: Wed, 25 Jan 2017 10:26:36 -0800 [thread overview]
Message-ID: <xmqqziifatcz.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170124003827.l2rimgitsyxsvtly@sigill.intra.peff.net> (Jeff King's message of "Mon, 23 Jan 2017 19:38:27 -0500")
Jeff King <peff@peff.net> writes:
> In older versions of git, if real_path() failed to resolve
> the alternate object store path, we would die() with an
> error. However, since 4ac9006f8 (real_path: have callers use
> real_pathdup and strbuf_realpath, 2016-12-12) we use the
> real_pathdup() function, which may return NULL. Since we
> don't check the return value, we can segfault.
>
> This is hard to trigger in practice, since we check that the
> path is accessible before creating the alternate_object_database
> struct. But it could be removed racily, or we could see a
> transient filesystem error.
>
> We could restore the original behavior by switching back to
> xstrdup(real_path()). However, dying is probably not the
> best option here. This whole function is best-effort
> already; there might not even be a repository around the
> shared objects at all. And if the alternate store has gone
> away, there are no objects to show.
>
> So let's just quietly return, as we would if we failed to
> open "refs/", or if upload-pack failed to start, etc.
That's sensible, methinks.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> transport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/transport.c b/transport.c
> index c86ba2eb8..74d0e45bd 100644
> --- a/transport.c
> +++ b/transport.c
> @@ -1215,6 +1215,8 @@ static int refs_from_alternate_cb(struct alternate_object_database *e,
> struct alternate_refs_data *cb = data;
>
> other = real_pathdup(e->path);
> + if (!other)
> + return 0;
> len = strlen(other);
>
> while (other[len-1] == '/')
next prev parent reply other threads:[~2017-01-25 18:26 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-24 0:37 [PATCH 0/12] reducing resource usage of for_each_alternate_ref Jeff King
2017-01-24 0:38 ` [PATCH 01/12] for_each_alternate_ref: handle failure from real_pathdup() Jeff King
2017-01-25 18:26 ` Junio C Hamano [this message]
2017-01-24 0:39 ` [PATCH 02/12] for_each_alternate_ref: stop trimming trailing slashes Jeff King
2017-01-24 0:40 ` [PATCH 03/12] for_each_alternate_ref: use strbuf for path allocation Jeff King
2017-01-25 18:29 ` Junio C Hamano
2017-01-25 18:40 ` Jeff King
2017-01-24 0:40 ` [PATCH 04/12] for_each_alternate_ref: pass name/oid instead of ref struct Jeff King
2017-01-24 0:44 ` [PATCH 05/12] for_each_alternate_ref: replace transport code with for-each-ref Jeff King
2017-01-25 19:00 ` Junio C Hamano
2017-01-24 0:45 ` [PATCH 06/12] clone: disable save_commit_buffer Jeff King
2017-01-25 19:11 ` Junio C Hamano
2017-01-25 19:27 ` Jeff King
2017-01-25 19:35 ` Jeff King
2017-01-25 21:07 ` Jeff King
2017-01-24 0:45 ` [PATCH 07/12] fetch-pack: cache results of for_each_alternate_ref Jeff King
2017-01-25 19:21 ` Junio C Hamano
2017-01-25 19:47 ` Jeff King
2017-01-24 0:46 ` [PATCH 08/12] add oidset API Jeff King
2017-01-24 20:26 ` Ramsay Jones
2017-01-24 20:35 ` Jeff King
2017-01-24 0:47 ` [PATCH 09/12] receive-pack: use oidset to de-duplicate .have lines Jeff King
2017-01-25 19:32 ` Junio C Hamano
2017-01-25 19:54 ` Jeff King
2017-01-24 0:47 ` [PATCH 10/12] receive-pack: fix misleading namespace/.have comment Jeff King
2017-01-24 0:48 ` [PATCH 11/12] receive-pack: treat namespace .have lines like alternates Jeff King
2017-01-25 19:51 ` Junio C Hamano
2017-01-25 19:58 ` Jeff King
2017-01-27 17:45 ` Lukas Fleischer
2017-01-27 17:58 ` Jeff King
2017-01-27 20:42 ` Junio C Hamano
2017-01-24 0:48 ` [PATCH 12/12] receive-pack: avoid duplicates between our refs and alternates Jeff King
2017-01-25 20:02 ` Junio C Hamano
2017-01-25 20:05 ` Jeff King
2017-01-24 1:33 ` [PATCH 0/12] reducing resource usage of for_each_alternate_ref Brandon Williams
2017-01-24 2:12 ` Jeff King
2017-02-08 20:52 ` [PATCH v2 0/11] " Jeff King
2017-02-08 20:52 ` [PATCH v2 01/11] for_each_alternate_ref: handle failure from real_pathdup() Jeff King
2017-02-08 20:52 ` [PATCH v2 02/11] for_each_alternate_ref: stop trimming trailing slashes Jeff King
2017-02-08 20:52 ` [PATCH v2 03/11] for_each_alternate_ref: use strbuf for path allocation Jeff King
2017-02-08 20:52 ` [PATCH v2 04/11] for_each_alternate_ref: pass name/oid instead of ref struct Jeff King
2017-02-08 20:53 ` [PATCH v2 05/11] for_each_alternate_ref: replace transport code with for-each-ref Jeff King
2017-02-08 20:53 ` [PATCH v2 06/11] fetch-pack: cache results of for_each_alternate_ref Jeff King
2017-02-08 20:53 ` [PATCH v2 07/11] add oidset API Jeff King
2017-02-08 20:53 ` [PATCH v2 08/11] receive-pack: use oidset to de-duplicate .have lines Jeff King
2017-02-08 20:53 ` [PATCH v2 09/11] receive-pack: fix misleading namespace/.have comment Jeff King
2017-02-08 20:53 ` [PATCH v2 10/11] receive-pack: treat namespace .have lines like alternates Jeff King
2017-02-08 20:53 ` [PATCH v2 11/11] receive-pack: avoid duplicates between our refs and alternates Jeff King
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