librt/clock_nanosleep.c

   1 /* Copyright (C) 2003, 2004, 2005 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <time.h>
  19 #include <errno.h>
  20
  21 #include <sysdep-cancel.h>
  22 #include <bits/kernel-features.h>
  23 #include "kernel-posix-cpu-timers.h"
  24
  25
  26 #ifdef __ASSUME_POSIX_TIMERS
  27 /* We can simply use the syscall.  The CPU clocks are not supported
  28    with this function.  */
  29 int
  30 clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
  31                  struct timespec *rem)
  32 {
  33   INTERNAL_SYSCALL_DECL (err);
  34   int r;
  35
  36   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
  37     return EINVAL;
  38   if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
  39     clock_id = MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED);
  40
  41   if (SINGLE_THREAD_P)
  42     r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req, rem);
  43   else
  44     {
  45       int oldstate = LIBC_CANCEL_ASYNC ();
  46
  47       r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req,
  48                             rem);
  49
  50       LIBC_CANCEL_RESET (oldstate);
  51     }
  52
  53   return (INTERNAL_SYSCALL_ERROR_P (r, err)
  54           ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
  55 }
  56
  57 #else
  58 # ifdef __NR_clock_nanosleep
  59 /* Is the syscall known to exist?  */
  60 extern int __libc_missing_posix_timers attribute_hidden;
  61
  62 /* The REALTIME and MONOTONIC clock might be available.  Try the
  63    syscall first.  */
  64 #  define SYSDEP_NANOSLEEP \
  65   if (!__libc_missing_posix_timers)                                           \
  66     {                                                                         \
  67       clockid_t syscall_clockid;                                              \
  68       INTERNAL_SYSCALL_DECL (err);                                            \
  69                                                                               \
  70       if (clock_id == CLOCK_THREAD_CPUTIME_ID)                                \
  71         return EINVAL;                                                        \
  72       if (clock_id == CLOCK_PROCESS_CPUTIME_ID)                               \
  73         syscall_clockid = MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED);          \
  74       else                                                                    \
  75         syscall_clockid = clock_id;                                           \
  76                                                                               \
  77       int oldstate = LIBC_CANCEL_ASYNC ();                                    \
  78                                                                               \
  79       int r = INTERNAL_SYSCALL (clock_nanosleep, err, 4,                      \
  80                                 syscall_clockid, flags, req, rem);            \
  81                                                                               \
  82       LIBC_CANCEL_RESET (oldstate);                                           \
  83                                                                               \
  84       if (!INTERNAL_SYSCALL_ERROR_P (r, err))                                 \
  85         return 0;                                                             \
  86                                                                               \
  87       if (INTERNAL_SYSCALL_ERRNO (r, err) != ENOSYS)                          \
  88         return INTERNAL_SYSCALL_ERRNO (r, err);                               \
  89                                                                               \
  90       __libc_missing_posix_timers = 1;                                        \
  91     }
  92 # endif
  93
  94 # include <sysdeps/unix/clock_nanosleep.c>
  95 #endif