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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: sundeep.kokkonda@gmail.com
Cc: libc-help@sourceware.org, libc-help-info@sourceware.org,
	libc-alpha@sourceware.org, libc-alpha-info@sourceware.org
Subject: Re: Suspected bug in mq_timedreceive
Date: Thu, 30 Jun 2022 08:10:54 -0300	[thread overview]
Message-ID: <EF4F6D95-CB93-4692-9944-262418851DB3@linaro.org> (raw)
In-Reply-To: <000f01d88c4b$df941790$9ebc46b0$@gmail.com>



> On 30 Jun 2022, at 03:37, sundeep.kokkonda--- via Libc-help <libc-help@sourceware.org> wrote:
> 
> Hello,
> 
> 
> 
> The mq_timedreceive code in
> glibc-2.33/sysdeps/unix/sysv/linux/mq_timedreceive.c does this:
> 
> 
> 
> ssize_t
> 
> _mq_timedreceive_time64 (mqd_t mqdes, char *_restrict msg_ptr, size_t
> msg_len,
> 
>                          unsigned int *__restrict msg_prio,
> 
>                          const struct _timespec64 *_restrict abs_timeout)
> 
> {
> 
> #ifndef __NR_mq_timedreceive_time64
> 
> #define __NR_mq_timedreceive_time64 __NR_mq_timedreceive
> 
> #endif
> 
>  int ret = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
> 
>                            msg_prio, abs_timeout);
> 
> #ifndef __ASSUME_TIME64_SYSCALLS
> 
>  if (ret == 0 || errno != ENOSYS)
> 
>    return ret;
> 
> 
> 
>  struct timespec ts32;
> 
>  if (abs_timeout != NULL)
> 
>    {
> 
>      if (! in_time_t_range (abs_timeout->tv_sec))
> 
> 
> 
> 
> 
> {           __set_errno (EOVERFLOW);           return -1;         }
> 
>      ts32 = valid_timespec64_to_timespec (*abs_timeout);
> 
>    }
> 
> 
> 
>  ret = SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len, msg_prio,
> 
>                        abs_timeout != NULL ? &ts32 : NULL);
> 
> #endif
> 
> 
> 
>  return ret;
> 
> }
> 
> 
> 
> This test is wrong:
> 
> 
> 
>  if (ret == 0 || errno != ENOSYS)
> 
>    return ret;
> 
> 
> 
> That test would be correct if mq_timedreceive returned 0 on success, as is
> the case for mq_timedsend. However, mq_timedreceive actually returns the
> number of bytes read, so the correct test is:
> 
> 
> 
>  If (ret >= 0 || errno != ENOSYS)
> 
>     return ret;

Yeah, this is incorrect.  I will open a bug an fix it on all affected releases.
At least for 2.36 the time64 code path is only used if the target date can not
be fit in 32-bit time_t.

      reply	other threads:[~2022-06-30 11:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-30  6:37 sundeep.kokkonda
2022-06-30 11:10 ` Adhemerval Zanella [this message]

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