Re: [PATCH v3 2/3] y2038: linux: Provide __mq_timedsend_time64 implementation

[Lukasz Majewski <lukma at denx dot de>]

Dear All,

> This patch provides new __mq_timedsend_time64 explicit 64 bit
> function for sending messages with absolute timeout.
> Moreover, a 32 bit version - __mq_timedsend has been refactored to
> internally use __mq_timedsend_time64.
> 
> The __mq_timedsend is now supposed to be used on systems still
> supporting 32 bit time (__TIMESIZE != 64) - hence the necessary
> conversion to 64 bit struct __timespec64 from struct timespec.
> 
> The new __mq_timedsend_time64 syscall available from Linux 5.1+ has
> been used, when applicable.
> 
> As this wrapper function is also used internally in the glibc, to
> e.g. provide mq_send implementation, an explicit check for
> abs_timeout being NULL has been added due to conversions between
> struct timespec and struct __timespec64. Before this change the Linux
> kernel handled this NULL pointer.
> 
> Build tests:
> - ./src/scripts/build-many-glibcs.py glibcs
> 
> Run-time tests:
> - Run specific tests on ARM/x86 32bit systems (qemu):
>   https://github.com/lmajewski/meta-y2038 and run tests:
>   https://github.com/lmajewski/y2038-tests/commits/master
> 
> Linux kernel, headers and minimal kernel version for glibc build test
> matrix:
> - Linux v5.1 (with mq_timedsend_time64) and glibc built with v5.1 as a
>   minimal kernel version (--enable-kernel="5.1.0")
>   The __ASSUME_TIME64_SYSCALLS flag defined.
> 
> - Linux v5.1 and default minimal kernel version
>   The __ASSUME_TIME64_SYSCALLS not defined, but kernel supports
>   mq_timedsend_time64 syscall.
> 
> - Linux v4.19 (no mq_timedsend_time64 support) with default minimal
> kernel version for contemporary glibc (3.2.0)
>   This kernel doesn't support mq_timedsend_time64 syscall, so the
> fallback to mq_timedsend is tested.
> 
> Above tests were performed with Y2038 redirection applied as well as
> without (so the __TIMESIZE != 64 execution path is checked as well).
> 

Are there any more comments?

> ---
> Changes for v2:
> - Fix indentation for __mq_timedsend
> - #include <bits/types/struct___timespec64.h> instead of
> <include/time.h> ---
>  include/mqueue.h                       |  9 +++++
>  sysdeps/unix/sysv/linux/mq_timedsend.c | 49
> ++++++++++++++++++++++++-- 2 files changed, 55 insertions(+), 3
> deletions(-)
> 
> diff --git a/include/mqueue.h b/include/mqueue.h
> index 3c66f1711e..81d30dbdf7 100644
> --- a/include/mqueue.h
> +++ b/include/mqueue.h
> @@ -10,4 +10,13 @@ extern __typeof (mq_timedreceive)
> __mq_timedreceive __nonnull ((2, 5)); hidden_proto (__mq_timedreceive)
>  hidden_proto (mq_setattr)
>  # endif
> +#if __TIMESIZE == 64
> +# define __mq_timedsend_time64 __mq_timedsend
> +#else
> +# include <bits/types/struct___timespec64.h>
> +extern int __mq_timedsend_time64 (mqd_t mqdes, const char *msg_ptr,
> +                                  size_t msg_len, unsigned int
> msg_prio,
> +                                  const struct __timespec64
> *abs_timeout); +librt_hidden_proto (__mq_timedsend_time64)
> +#endif
>  #endif
> diff --git a/sysdeps/unix/sysv/linux/mq_timedsend.c
> b/sysdeps/unix/sysv/linux/mq_timedsend.c index 888ec6744a..0d5a860c48
> 100644 --- a/sysdeps/unix/sysv/linux/mq_timedsend.c
> +++ b/sysdeps/unix/sysv/linux/mq_timedsend.c
> @@ -22,12 +22,55 @@
>  /* Add message pointed by MSG_PTR to message queue MQDES, stop
> blocking on full message queue if ABS_TIMEOUT expires.  */
>  int
> -__mq_timedsend (mqd_t mqdes, const char *msg_ptr, size_t msg_len,
> -		unsigned int msg_prio, const struct timespec
> *abs_timeout) +__mq_timedsend_time64 (mqd_t mqdes, const char
> *msg_ptr, size_t msg_len,
> +                       unsigned int msg_prio,
> +                       const struct __timespec64 *abs_timeout)
>  {
> +#ifdef __ASSUME_TIME64_SYSCALLS
> +# ifndef __NR_mq_timedsend_time64
> +#  define __NR_mq_timedsend_time64 __NR_mq_timedsend
> +# endif
> +  return SYSCALL_CANCEL (mq_timedsend_time64, mqdes, msg_ptr,
> msg_len, msg_prio,
> +                         abs_timeout);
> +#else
> +  int ret = SYSCALL_CANCEL (mq_timedsend_time64, mqdes, msg_ptr,
> msg_len,
> +                            msg_prio, abs_timeout);
> +  if (ret == 0 || errno != ENOSYS)
> +    return ret;
> +
> +  struct timespec ts32;
> +  if (abs_timeout)
> +    {
> +      if (! in_time_t_range (abs_timeout->tv_sec))
> +        {
> +          __set_errno (EOVERFLOW);
> +          return -1;
> +        }
> +
> +      ts32 = valid_timespec64_to_timespec (*abs_timeout);
> +    }
> +
>    return SYSCALL_CANCEL (mq_timedsend, mqdes, msg_ptr, msg_len,
> msg_prio,
> -			 abs_timeout);
> +                         abs_timeout ? &ts32 : NULL);
> +#endif
> +}
> +
> +#if __TIMESIZE != 64
> +librt_hidden_def (__mq_timedsend_time64)
> +
> +int
> +__mq_timedsend (mqd_t mqdes, const char *msg_ptr, size_t msg_len,
> +                unsigned int msg_prio, const struct timespec
> *abs_timeout) +{
> +  struct __timespec64 ts64;
> +  if (abs_timeout)
> +    ts64 = valid_timespec_to_timespec64 (*abs_timeout);
> +
> +  return __mq_timedsend_time64 (mqdes, msg_ptr, msg_len, msg_prio,
> +                                abs_timeout ? &ts64 : NULL);
>  }
> +#endif
> +
>  hidden_def (__mq_timedsend)
>  weak_alias (__mq_timedsend, mq_timedsend)
>  hidden_weak (mq_timedsend)




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

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