From: Andreas Schwab <schwab@suse.de>
To: Florian Weimer <fweimer@redhat.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] Avoid concurrency problem in ldconfig (bug 23973)
Date: Thu, 18 Apr 2019 17:16:01 +0200 [thread overview]
Message-ID: <mvmr29zpcni.fsf@suse.de> (raw)
In-Reply-To: <87zhonv08p.fsf@oldenburg2.str.redhat.com> (Florian Weimer's message of "Thu, 18 Apr 2019 16:47:34 +0200")
On Apr 18 2019, Florian Weimer <fweimer@redhat.com> wrote:
> * Andreas Schwab:
>
>> On Apr 18 2019, Florian Weimer <fweimer@redhat.com> wrote:
>>
>>> * Andreas Schwab:
>>>
>>>> Use a unique name for the temporary file when updating the ld.so cache, so
>>>> that two concurrent runs of ldconfig don't write to the same file.
>>>>
>>>> * elf/cache.c (save_cache): Use unique temporary name.
>>>> (save_aux_cache): Likewise.
>>>
>>> The downside of this change is that if ldconfig is interrupted, the
>>> temporary file never goes away.
>>>
>>> Ideally, we would use O_TMPFILE if supported by the (file) system, but
>>> that can get quite involved.
>>
>> That shortens the window, but won't close it, since we need a name to
>> pass to rename in any case.
>
> The difference is that with a fixed name, the next ldconfig run will use
> the same name and rename, cleaning up. With a random, unique name, that
> automatic cleanup is gone.
O_TMPFILE won't change that.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
next prev parent reply other threads:[~2019-04-18 15:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 16:51 [PATCH] Avoid concurrency problem in ldconfig (bug 23973) Andreas Schwab
2019-04-18 12:01 ` Florian Weimer
2019-04-18 12:09 ` Christian Brauner
2019-04-18 12:11 ` Florian Weimer
2019-04-18 12:59 ` Andreas Schwab
2019-04-18 14:47 ` Florian Weimer
2019-04-18 15:16 ` Andreas Schwab [this message]
2019-04-18 15:52 ` Florian Weimer
2019-04-18 16:04 ` Andreas Schwab
-- strict thread matches above, loose matches on Subject: below --
2019-01-21 15:30 Andreas Schwab
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