glibc/nptl/lll_timedlock_wait.c

/* Timed low level locking for pthread library.  Generic futex-using version.
   Copyright (C) 2003-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <atomic.h>
#include <errno.h>
#include <lowlevellock.h>
#include <sys/time.h>
#include <time.h>


int
__lll_clocklock_wait (int *futex, int val, clockid_t clockid,
		      const struct timespec *abstime, int private)
{
  struct timespec ts, *tsp = NULL;

  if (abstime != NULL)
    {
      /* Reject invalid timeouts.  */
      if (! valid_nanoseconds (abstime->tv_nsec))
        return EINVAL;

      /* Get the current time. This can only fail if clockid is not valid.  */
      if (__glibc_unlikely (__clock_gettime (clockid, &ts) != 0))
        return EINVAL;

      /* Compute relative timeout.  */
      ts.tv_sec = abstime->tv_sec - ts.tv_sec;
      ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
      if (ts.tv_nsec < 0)
        {
	  ts.tv_nsec += 1000000000;
	  --ts.tv_sec;
        }

      if (ts.tv_sec < 0)
        return ETIMEDOUT;

      tsp = &ts;
    }

  /* If *futex == val, wait until woken or timeout.  */
  lll_futex_timed_wait (futex, val, tsp, private);

  return 0;
}