sysdeps/unix/sysv/linux/pselect.c

   1 /* Copyright (C) 2006-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2006.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <time.h>
  22 #include <sys/poll.h>
  23 #include <kernel-features.h>
  24 #include <sysdep-cancel.h>
  25
  26
  27 #ifdef __NR_pselect6
  28 # ifndef __ASSUME_PSELECT
  29 static int __generic_pselect (int nfds, fd_set *readfds, fd_set *writefds,
  30                               fd_set *exceptfds,
  31                               const struct timespec *timeout,
  32                               const sigset_t *sigmask);
  33 # endif
  34
  35
  36 int
  37 __pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
  38            const struct timespec *timeout, const sigset_t *sigmask)
  39 {
  40   /* The Linux kernel can in some situations update the timeout value.
  41      We do not want that so use a local variable.  */
  42   struct timespec tval;
  43   if (timeout != NULL)
  44     {
  45       tval = *timeout;
  46       timeout = &tval;
  47     }
  48
  49   /* Note: the system call expects 7 values but on most architectures
  50      we can only pass in 6 directly.  If there is an architecture with
  51      support for more parameters a new version of this file needs to
  52      be created.  */
  53   struct
  54   {
  55     __syscall_ulong_t ss;
  56     __syscall_ulong_t ss_len;
  57   } data;
  58
  59   data.ss = (__syscall_ulong_t) (uintptr_t) sigmask;
  60   data.ss_len = _NSIG / 8;
  61
  62   int result;
  63
  64 #ifndef CALL_PSELECT6
  65 # define CALL_PSELECT6(nfds, readfds, writefds, exceptfds, timeout, data) \
  66   SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, timeout, data)
  67 #endif
  68
  69   result = CALL_PSELECT6 (nfds, readfds, writefds, exceptfds, timeout,
  70                           &data);
  71
  72 # ifndef __ASSUME_PSELECT
  73   if (result == -1 && errno == ENOSYS)
  74     result = __generic_pselect (nfds, readfds, writefds, exceptfds, timeout,
  75                                 sigmask);
  76 # endif
  77
  78   return result;
  79 }
  80 weak_alias (__pselect, pselect)
  81
  82 # ifndef __ASSUME_PSELECT
  83 #  define __pselect static __generic_pselect
  84 # endif
  85 #endif
  86
  87 #ifndef __ASSUME_PSELECT
  88 # include <misc/pselect.c>
  89 #endif