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