sysdeps/unix/sysv/linux/microblaze/pselect32.c

   1 /* Synchronous I/O multiplexing.  Linux/microblaze version.
   2    Copyright (C) 2019-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <time.h>
  22 #include <sys/poll.h>
  23 #include <sysdep-cancel.h>
  24
  25 #ifndef __ASSUME_TIME64_SYSCALL
  26 #include <sysdeps/unix/sysv/linux/pselect32.c>
  27 #elif !defined __ASSUME_PSELECT
  28 int
  29 __pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
  30              fd_set *exceptfds, const struct __timespec64 *timeout,
  31              const sigset_t *sigmask)
  32 {
  33   /* The fallback uses 'select' which shows the race condition regarding
  34      signal mask set/restore, requires two additional syscalls, and has
  35      a worse timeout precision (microseconds instead of nanoseconds).  */
  36
  37   struct timeval tv32, *ptv32 = NULL;
  38   if (timeout != NULL)
  39     {
  40       if (! valid_nanoseconds (timeout->tv_nsec))
  41         {
  42           __set_errno (EINVAL);
  43           return -1;
  44         }
  45
  46       tv32 = valid_timespec64_to_timeval (*timeout);
  47       ptv32 = &tv32;
  48     }
  49
  50   sigset_t savemask;
  51   if (sigmask != NULL)
  52     __sigprocmask (SIG_SETMASK, sigmask, &savemask);
  53
  54   /* select itself is a cancellation entrypoint.  */
  55   int ret = __select (nfds, readfds, writefds, exceptfds, ptv32);
  56
  57   if (sigmask != NULL)
  58     __sigprocmask (SIG_SETMASK, &savemask, NULL);
  59
  60   return ret;
  61 }
  62 #endif /* __ASSUME_PSELECT  */