From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>,
Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH 5/8] posix: Do not clobber errno by atfork handlers
Date: Wed, 10 Mar 2021 17:10:35 -0300 [thread overview]
Message-ID: <09b94a9b-905d-db39-3566-767c097f4348@linaro.org> (raw)
In-Reply-To: <87o8fs4mm9.fsf@oldenburg.str.redhat.com>
On 09/03/2021 08:01, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
>
>> Checked on x86_64-linux-gnu.
>> ---
>> posix/fork.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/posix/fork.c b/posix/fork.c
>> index 4c9e60f187..7f27fb8338 100644
>> --- a/posix/fork.c
>> +++ b/posix/fork.c
>> @@ -68,7 +68,7 @@ __libc_fork (void)
>> }
>>
>> pid_t pid = _Fork ();
>> -
>> + int save_errno = errno;
>> if (pid == 0)
>> {
>> /* Reset the lock state in the multi-threaded case. */
>> @@ -107,6 +107,8 @@ __libc_fork (void)
>> __run_fork_handlers (pid == 0 ? atfork_run_child : atfork_run_parent,
>> multiple_threads);
>>
>> + if (pid < 0)
>> + __set_errno (save_errno);
>> return pid;
>> }
>> weak_alias (__libc_fork, __fork)
>
> Why is this condition correct? Shouldn't it be pid >= 0?
But pid >= 0 is a valid call which should not set errno. The idea is
to return the _Fork error value even if some atfork handler in the
parent does clobber it.
>
> I wonder if this should be part of __run_fork_handlers, so that fork
> handlers always observe the original errno value.
I am not sure about it, checking the errno without actually calling a
function that might setting it is error-prone imho.
next prev parent reply other threads:[~2021-03-10 20:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 15:11 [PATCH 1/8] posix: Consolidate register-atfork Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 2/8] linux: Use __libc_single_threaded on fork Adhemerval Zanella
2021-02-02 15:15 ` Andreas Schwab
2021-02-02 16:40 ` Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 3/8] posix: Consolidate fork implementation Adhemerval Zanella
2021-03-09 10:58 ` Florian Weimer
2021-03-10 17:07 ` Adhemerval Zanella
2021-03-11 13:56 ` Andreas Schwab
2021-03-11 13:59 ` Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 4/8] nptl: Move fork into libc Adhemerval Zanella
2021-03-08 13:42 ` Florian Weimer
2021-03-10 17:08 ` Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 5/8] posix: Do not clobber errno by atfork handlers Adhemerval Zanella
2021-03-09 11:01 ` Florian Weimer
2021-03-10 20:10 ` Adhemerval Zanella [this message]
2021-03-11 13:25 ` Florian Weimer
2021-03-11 14:07 ` Adhemerval Zanella
2021-03-11 14:22 ` Andreas Schwab
2021-03-11 14:25 ` Florian Weimer
2021-03-11 15:29 ` Adhemerval Zanella
2021-03-11 15:32 ` Florian Weimer
2021-03-11 17:25 ` Adhemerval Zanella
2021-03-11 19:23 ` Florian Weimer
2021-03-11 19:30 ` Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 6/8] Consolidate pthread_atfork Adhemerval Zanella
2021-03-09 11:09 ` Florian Weimer
2021-03-10 20:15 ` Adhemerval Zanella
2021-02-02 15:11 ` [PATCH 7/8] support: Add xpthread_kill Adhemerval Zanella
2021-03-08 12:13 ` Florian Weimer
2021-02-02 15:11 ` [PATCH 8/8] posix: Add _Fork [BZ #4737] Adhemerval Zanella
2021-02-02 15:48 ` Andreas Schwab
2021-02-02 18:22 ` Joseph Myers
2021-02-11 15:26 ` [PATCH v2] " Adhemerval Zanella
2021-02-11 16:21 ` Andreas Schwab
2021-02-11 17:10 ` Adhemerval Zanella
2021-02-11 17:33 ` Andreas Schwab
2021-02-11 17:36 ` Adhemerval Zanella
2021-03-08 13:04 ` [PATCH 1/8] posix: Consolidate register-atfork Florian Weimer
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