From: Florian Weimer <fweimer@redhat.com>
To: Andreas Schwab <schwab@suse.de>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] Avoid concurrency problem in ldconfig (bug 23973)
Date: Thu, 18 Apr 2019 16:47:34 +0200 [thread overview]
Message-ID: <87zhonv08p.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <mvmv9zbpiyl.fsf@suse.de> (Andreas Schwab's message of "Thu, 18 Apr 2019 14:59:46 +0200")
* 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.
Thanks,
Florian
next prev parent reply other threads:[~2019-04-18 14:47 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 [this message]
2019-04-18 15:16 ` Andreas Schwab
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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