[17/23] linux: Add time64 select support

  The syscall __NR_pselect6_time64 (32-bit) or __NR_pselect6 (64-bit)
is used as default.  For architectures with __ASSUME_TIME64_SYSCALLS
the 32-bit fallback uses __NR_select/__NR__newselect or __NR_pselect6
(it should cover the microblaze case where older kernels do not
provide __NR_pselect6).

Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
kernel).
---
 include/sys/select.h             |  8 +++
 include/time.h                   |  6 ++
 sysdeps/unix/sysv/linux/select.c | 96 +++++++++++++++++++++++---------
 3 files changed, 83 insertions(+), 27 deletions(-)
  

Ping.

On 13/07/2020 14:10, Adhemerval Zanella wrote:
> The syscall __NR_pselect6_time64 (32-bit) or __NR_pselect6 (64-bit)
> is used as default.  For architectures with __ASSUME_TIME64_SYSCALLS
> the 32-bit fallback uses __NR_select/__NR__newselect or __NR_pselect6
> (it should cover the microblaze case where older kernels do not
> provide __NR_pselect6).
> 
> Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
> kernel).
> ---
>  include/sys/select.h             |  8 +++
>  include/time.h                   |  6 ++
>  sysdeps/unix/sysv/linux/select.c | 96 +++++++++++++++++++++++---------
>  3 files changed, 83 insertions(+), 27 deletions(-)
> 
> diff --git a/include/sys/select.h b/include/sys/select.h
> index 460dee9295..370b662ea7 100644
> --- a/include/sys/select.h
> +++ b/include/sys/select.h
> @@ -5,13 +5,21 @@
>  /* Now define the internal interfaces.  */
>  # if __TIMESIZE == 64
>  #  define __pselect64 __pselect
> +#  define __select64  __select
>  #else
>  # include <struct___timespec64.h>
> +# include <struct___timeval64.h>
> +
>  extern int __pselect64 (int __nfds, fd_set *__readfds,
>  			fd_set *__writefds, fd_set *__exceptfds,
>  			const struct __timespec64 *__timeout,
>  			const __sigset_t *__sigmask);
>  libc_hidden_proto (__pselect64)
> +
> +extern int __select64 (int __nfds, fd_set *__readfds,
> +		       fd_set *__writefds, fd_set *__exceptfds,
> +		       struct __timeval64 *__timeout);
> +libc_hidden_proto (__select64)
>  #endif
>  extern int __pselect (int __nfds, fd_set *__readfds,
>  		      fd_set *__writefds, fd_set *__exceptfds,
> diff --git a/include/time.h b/include/time.h
> index fe4da9ca10..936486e206 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -464,6 +464,12 @@ valid_timespec_to_timeval32 (const struct timespec ts)
>    return (struct __timeval32) { (time_t) ts.tv_sec, ts.tv_nsec / 1000 };
>  }
>  
> +static inline struct __timeval64
> +valid_timespec_to_timeval64 (const struct timespec ts)
> +{
> +  return (struct __timeval64) { (time_t) ts.tv_sec, ts.tv_nsec / 1000 };
> +}
> +
>  /* Check if a value is in the valid nanoseconds range. Return true if
>     it is, false otherwise.  */
>  static inline bool
> diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
> index 54c50edba2..df4fcc3362 100644
> --- a/sysdeps/unix/sysv/linux/select.c
> +++ b/sysdeps/unix/sysv/linux/select.c
> @@ -21,6 +21,7 @@
>  #include <sys/select.h>
>  #include <errno.h>
>  #include <sysdep-cancel.h>
> +#include <time64-support.h>
>  
>  /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
>     readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
> @@ -28,43 +29,84 @@
>     after waiting the interval specified therein.  Returns the number of ready
>     descriptors, or -1 for errors.  */
>  
> -#ifdef __NR__newselect
> -# undef __NR_select
> -# define __NR_select __NR__newselect
> -#endif
> -
>  int
> -__select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> -	  struct timeval *timeout)
> +__select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> +	    struct __timeval64 *timeout)
>  {
> -#ifdef __NR_select
> -  return SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds,
> -			 timeout);
> -#else
> -  int result;
> -  struct timespec ts, *tsp = NULL;
> -
> -  if (timeout)
> +  struct __timespec64 ts64, *pts64 = NULL;
> +  if (timeout != NULL)
>      {
> -      TIMEVAL_TO_TIMESPEC (timeout, &ts);
> -      tsp = &ts;
> +      ts64 = timeval64_to_timespec64 (*timeout);
> +      pts64 = &ts64;
>      }
>  
> -  result = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, tsp,
> -			   NULL);
> -
> -  if (timeout)
> +#ifndef __NR_pselect6_time64
> +# define __NR_pselect6_time64 __NR_pselect6
> +#endif
> +  int r;
> +  if (supports_time64 ())
>      {
> -      /* Linux by default will update the timeout after a pselect6 syscall
> -         (though the pselect() glibc call suppresses this behavior).
> -         Since select() on Linux has the same behavior as the pselect6
> -         syscall, we update the timeout here.  */
> -      TIMESPEC_TO_TIMEVAL (timeout, &ts);
> +      r = SYSCALL_CANCEL (pselect6_time64, nfds, readfds, writefds, exceptfds,
> +			  pts64, NULL);
> +      if (r == 0 || errno != ENOSYS)
> +	{
> +	  if (timeout != NULL)
> +	    TIMEVAL_TO_TIMESPEC (timeout, &ts64);
> +	  return r;
> +	}
> +
> +      mark_time64_unsupported ();
>      }
>  
> -  return result;
> +#ifndef __ASSUME_TIME64_SYSCALLS
> +  struct timespec ts32, *pts32 = NULL;
> +  if (timeout != NULL)
> +    {
> +      if (! in_time_t_range (timeout->tv_sec))
> +	{
> +	  __set_errno (EINVAL);
> +	  return -1;
> +	}
> +      ts32 = valid_timespec64_to_timespec (ts64);
> +      pts32 = &ts32;
> +    }
> +# ifndef __ASSUME_PSELECT
> +#  ifdef __NR__newselect
> +#   undef __NR_select
> +#   define __NR_select __NR__newselect
> +#  endif
> +  r = SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds, pts32);
> +# else
> +  r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32,
> +		      NULL);
> +# endif
> +  if (r >= 0 && timeout != NULL)
> +    *timeout = valid_timespec_to_timeval64 (ts32);
>  #endif
> +
> +  return r;
>  }
> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__select64)
> +
> +int
> +__select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> +	  struct timeval *timeout)
> +{
> +  struct __timeval64 tv64, *ptv64 = NULL;
> +  if (timeout != 0)
> +    {
> +      tv64 = valid_timeval_to_timeval64 (*timeout);
> +      ptv64 = &tv64;
> +    }
> +  int r = __select64 (nfds, readfds, writefds, exceptfds, ptv64);
> +  if (r >= 0 && timeout != NULL)
> +    /* The remanining timeout will be always less the input TIMEOUT.  */
> +    *timeout = valid_timeval64_to_timeval (tv64);
> +  return r;
> +}
> +#endif
>  libc_hidden_def (__select)
>  
>  weak_alias (__select, select)
>