sysdeps/unix/sysv/linux/clock_nanosleep.c

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <time.h>
  20
  21 #include <sysdep-cancel.h>
  22 #include "kernel-features.h"
  23
  24
  25 #ifdef __ASSUME_POSIX_TIMERS
  26 /* We can simply use the syscall.  The CPU clocks are not supported
  27    with this function.  */
  28 int
  29 clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
  30                  struct timespec *rem)
  31 {
  32   INTERNAL_SYSCALL_DECL (err);
  33   int r;
  34
  35   if (SINGLE_THREAD_P)
  36     r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req, rem);
  37   else
  38     {
  39       int oldstate = LIBC_CANCEL_ASYNC ();
  40
  41       r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req,
  42                             rem);
  43
  44       LIBC_CANCEL_RESET (oldstate);
  45     }
  46
  47   return (INTERNAL_SYSCALL_ERROR_P (r, err)
  48           ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
  49 }
  50
  51 #else
  52 # ifdef __NR_clock_nanosleep
  53 /* Is the syscall known to exist?  */
  54 extern int __libc_missing_posix_timers attribute_hidden;
  55
  56 /* The REALTIME and MONOTONIC clock might be available.  Try the
  57    syscall first.  */
  58 #  define SYSDEP_NANOSLEEP \
  59   if (!__libc_missing_posix_timers)                                           \
  60     {                                                                         \
  61       INTERNAL_SYSCALL_DECL (err);                                            \
  62                                                                               \
  63       int oldstate = LIBC_CANCEL_ASYNC ();                                    \
  64                                                                               \
  65       int r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags,     \
  66                                 req, rem);                                    \
  67                                                                               \
  68       LIBC_CANCEL_RESET (oldstate);                                           \
  69                                                                               \
  70       if (!INTERNAL_SYSCALL_ERROR_P (r, err))                                 \
  71         return 0;                                                             \
  72                                                                               \
  73       if (INTERNAL_SYSCALL_ERRNO (r, err) != ENOSYS)                          \
  74         return INTERNAL_SYSCALL_ERRNO (r, err);                               \
  75                                                                               \
  76       __libc_missing_posix_timers = 1;                                        \
  77     }
  78 # endif
  79
  80 # include <sysdeps/unix/clock_nanosleep.c>
  81 #endif