sysdeps/unix/sysv/linux/pselect.c

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