sysdeps/unix/sysv/linux/pselect.c

   1 /* Copyright (C) 2006, 2007 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <time.h>
  23 #include <sys/poll.h>
  24 #include <kernel-features.h>
  25 #include <sysdep-cancel.h>
  26
  27
  28 #ifdef __NR_pselect6
  29 # ifndef __ASSUME_PSELECT
  30 static int __generic_pselect (int nfds, fd_set *readfds, fd_set *writefds,
  31                               fd_set *exceptfds,
  32                               const struct timespec *timeout,
  33                               const sigset_t *sigmask);
  34 # endif
  35
  36
  37 int
  38 __pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
  39            const struct timespec *timeout, const sigset_t *sigmask)
  40 {
  41   /* The Linux kernel can in some situations update the timeout value.
  42      We do not want that so use a local variable.  */
  43   struct timespec tval;
  44   if (timeout != NULL)
  45     {
  46       tval = *timeout;
  47       timeout = &tval;
  48     }
  49
  50   /* Note: the system call expects 7 values but on most architectures
  51      we can only pass in 6 directly.  If there is an architecture with
  52      support for more parameters a new version of this file needs to
  53      be created.  */
  54   struct
  55   {
  56     const sigset_t *ss;
  57     size_t ss_len;
  58   } data;
  59
  60   data.ss = sigmask;
  61   data.ss_len = _NSIG / 8;
  62
  63   int result;
  64
  65 #ifndef CALL_PSELECT6
  66 # define CALL_PSELECT6(nfds, readfds, writefds, exceptfds, timeout, data) \
  67   INLINE_SYSCALL (pselect6, 6, nfds, readfds, writefds, exceptfds,            \
  68                   timeout, data)
  69 #endif
  70
  71   if (SINGLE_THREAD_P)
  72     result = CALL_PSELECT6 (nfds, readfds, writefds, exceptfds, timeout,
  73                             &data);
  74   else
  75     {
  76       int oldtype = LIBC_CANCEL_ASYNC ();
  77
  78       result = CALL_PSELECT6 (nfds, readfds, writefds, exceptfds, timeout,
  79                               &data);
  80
  81       LIBC_CANCEL_RESET (oldtype);
  82     }
  83
  84 # ifndef __ASSUME_PSELECT
  85   if (result == -1 && errno == ENOSYS)
  86     result = __generic_pselect (nfds, readfds, writefds, exceptfds, timeout,
  87                                 sigmask);
  88 # endif
  89
  90   return result;
  91 }
  92 weak_alias (__pselect, pselect)
  93 strong_alias (__pselect, __libc_pselect)
  94
  95 # ifndef __ASSUME_PSELECT
  96 #  define __pselect static __generic_pselect
  97 # endif
  98 #endif
  99
 100 #ifndef __ASSUME_PSELECT
 101 # include <misc/pselect.c>
 102 #endif