nptl/sysdeps/unix/sysv/linux/s390/sem_timedwait.c

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
   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 <sysdep.h>
  22 #include <lowlevellock.h>
  23 #include <internaltypes.h>
  24 #include <semaphore.h>
  25
  26 #include <pthreadP.h>
  27 #include <shlib-compat.h>
  28
  29
  30 int
  31 sem_timedwait (sem, abstime)
  32      sem_t *sem;
  33      const struct timespec *abstime;
  34 {
  35   /* First check for cancellation.  */
  36   CANCELLATION_P (THREAD_SELF);
  37
  38   int *futex = (int *) sem;
  39   int oldval;
  40   int newval;
  41   int err;
  42
  43   do
  44     {
  45       /* Atomically decrement semaphore counter if it is > 0.  */
  46       lll_compare_and_swap (futex, oldval, newval,
  47                             "ltr %2,%1; jnp 1f; ahi %2,-1");
  48       /* oldval != newval if the semaphore count has been decremented.  */
  49       if (oldval != newval)
  50         return 0;
  51
  52       /* Check for invalid timeout values.  */
  53       if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
  54         {
  55           __set_errno (EINVAL);
  56           return -1;
  57         }
  58
  59       /* Get the current time.  */
  60       struct timeval tv;
  61       (void) __gettimeofday (&tv, NULL);
  62
  63       /* Compute the relative timeout.  */
  64       struct timespec rt;
  65       rt.tv_sec = abstime->tv_sec - tv.tv_sec;
  66       rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
  67       if (rt.tv_nsec < 0)
  68         {
  69           rt.tv_nsec += 1000000000;
  70           --rt.tv_sec;
  71         }
  72       /* Already timed out.  */
  73       if (rt.tv_sec < 0)
  74         {
  75           __set_errno (ETIMEDOUT);
  76           return -1;
  77         }
  78
  79       /* Enable asynchronous cancellation.  Required by the standard.  */
  80       int oldtype = __pthread_enable_asynccancel ();
  81
  82       /* Do wait.  */
  83       err = lll_futex_timed_wait (futex, 0, &rt);
  84
  85       /* Disable asynchronous cancellation.  */
  86       __pthread_disable_asynccancel (oldtype);
  87
  88       /* Returned after timing out?  */
  89       if (err == -ETIMEDOUT)
  90         {
  91           __set_errno (ETIMEDOUT);
  92           return -1;
  93         }
  94     }
  95   while (err == 0 || err == -EWOULDBLOCK);
  96
  97   __set_errno (-err);
  98   return -1;
  99 }