sysdeps/unix/sysv/linux/clock_settime.c

   1 /* Copyright (C) 2003, 2004, 2006, 2010 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 <errno.h>
  19 #include <sysdep.h>
  20
  21 #include "kernel-posix-cpu-timers.h"
  22 #include <kernel-features.h>
  23
  24 #ifndef HAVE_CLOCK_GETRES_VSYSCALL
  25 # undef INTERNAL_VSYSCALL
  26 # define INTERNAL_VSYSCALL INTERNAL_SYSCALL
  27 # undef INLINE_VSYSCALL
  28 # define INLINE_VSYSCALL INLINE_SYSCALL
  29 #else
  30 # include <bits/libc-vdso.h>
  31 #endif
  32
  33 #if __ASSUME_POSIX_CPU_TIMERS <= 0 && defined __NR_clock_settime
  34 extern int __libc_missing_posix_timers attribute_hidden;
  35 extern int __libc_missing_posix_cpu_timers attribute_hidden;
  36
  37 static int
  38 maybe_syscall_settime_cpu (clockid_t clock_id, const struct timespec *tp)
  39 {
  40   int e = EINVAL;
  41
  42   if (!__libc_missing_posix_cpu_timers)
  43     {
  44       INTERNAL_SYSCALL_DECL (err);
  45       int r = INTERNAL_SYSCALL (clock_settime, err, 2, clock_id, tp);
  46       if (!INTERNAL_SYSCALL_ERROR_P (r, err))
  47         return 0;
  48
  49       e = INTERNAL_SYSCALL_ERRNO (r, err);
  50 # ifndef __ASSUME_POSIX_TIMERS
  51       if (e == ENOSYS)
  52         {
  53           __libc_missing_posix_timers = 1;
  54           __libc_missing_posix_cpu_timers = 1;
  55           e = EINVAL;
  56         }
  57       else
  58 # endif
  59         {
  60           if (e == EINVAL)
  61             {
  62               /* Check whether the kernel supports CPU clocks at all.
  63                  If not, record it for the future.  */
  64               r = INTERNAL_VSYSCALL (clock_getres, err, 2,
  65                                      MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED),
  66                                      NULL);
  67               if (INTERNAL_SYSCALL_ERROR_P (r, err))
  68                 __libc_missing_posix_cpu_timers = 1;
  69             }
  70         }
  71     }
  72
  73   return e;
  74 }
  75 #endif
  76
  77
  78 #ifdef __ASSUME_POSIX_TIMERS
  79 /* This means the REALTIME clock is definitely supported in the
  80    kernel.  */
  81 # define SYSDEP_SETTIME \
  82   case CLOCK_REALTIME:                                                        \
  83     retval = INLINE_SYSCALL (clock_settime, 2, clock_id, tp);                 \
  84     break
  85 #elif defined __NR_clock_settime
  86 /* Is the syscall known to exist?  */
  87 extern int __libc_missing_posix_timers attribute_hidden;
  88
  89 /* The REALTIME clock might be available.  Try the syscall first.  */
  90 # define SYSDEP_SETTIME \
  91   case CLOCK_REALTIME:                                                        \
  92   case CLOCK_REALTIME_COARSE:                                                 \
  93     {                                                                         \
  94       int e = EINVAL;                                                         \
  95                                                                               \
  96       if (!__libc_missing_posix_timers)                                       \
  97         {                                                                     \
  98           INTERNAL_SYSCALL_DECL (err);                                        \
  99           int r = INTERNAL_SYSCALL (clock_settime, err, 2, clock_id, tp);     \
 100           if (!INTERNAL_SYSCALL_ERROR_P (r, err))                             \
 101             {                                                                 \
 102               retval = 0;                                                     \
 103               break;                                                          \
 104             }                                                                 \
 105                                                                               \
 106           e = INTERNAL_SYSCALL_ERRNO (r, err);                                \
 107           if (e == ENOSYS)                                                    \
 108             {                                                                 \
 109               __libc_missing_posix_timers = 1;                                \
 110               e = EINVAL;                                                     \
 111             }                                                                 \
 112         }                                                                     \
 113                                                                               \
 114       /* Fallback code.  */                                                   \
 115       if (e == EINVAL && clock_id == CLOCK_REALTIME)                          \
 116         HANDLE_REALTIME;                                                      \
 117       else                                                                    \
 118         {                                                                     \
 119           __set_errno (e);                                                    \
 120           retval = -1;                                                        \
 121         }                                                                     \
 122     }                                                                         \
 123     break
 124 #endif
 125
 126 #ifdef __NR_clock_settime
 127 /* We handled the REALTIME clock here.  */
 128 # define HANDLED_REALTIME       1
 129 #endif
 130
 131 #if __ASSUME_POSIX_CPU_TIMERS > 0
 132 # define HANDLED_CPUTIME 1
 133 # define SYSDEP_SETTIME_CPU \
 134   retval = INLINE_SYSCALL (clock_settime, 2, clock_id, tp)
 135 #elif defined __NR_clock_settime
 136 # define SYSDEP_SETTIME_CPU \
 137   retval = maybe_syscall_settime_cpu (clock_id, tp);                          \
 138   if (retval == 0)                                                            \
 139     break;                                                                    \
 140   if (retval != EINVAL || !__libc_missing_posix_cpu_timers)                   \
 141     {                                                                         \
 142       __set_errno (retval);                                                   \
 143       retval = -1;                                                            \
 144       break;                                                                  \
 145     }                                                                         \
 146   do { } while (0)
 147 #endif
 148
 149 #include <sysdeps/unix/clock_settime.c>