nptl/lll_timedlock_wait.c

   1 /* Timed low level locking for pthread library.  Generic futex-using version.
   2    Copyright (C) 2003-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <atomic.h>
  21 #include <errno.h>
  22 #include <lowlevellock.h>
  23 #include <sys/time.h>
  24 #include <time.h>
  25
  26
  27 int
  28 __lll_clocklock_wait (int *futex, int val, clockid_t clockid,
  29                       const struct timespec *abstime, int private)
  30 {
  31   struct timespec ts, *tsp = NULL;
  32
  33   if (abstime != NULL)
  34     {
  35       /* Reject invalid timeouts.  */
  36       if (! valid_nanoseconds (abstime->tv_nsec))
  37         return EINVAL;
  38
  39       /* Get the current time. This can only fail if clockid is not valid.  */
  40       if (__glibc_unlikely (__clock_gettime (clockid, &ts) != 0))
  41         return EINVAL;
  42
  43       /* Compute relative timeout.  */
  44       ts.tv_sec = abstime->tv_sec - ts.tv_sec;
  45       ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
  46       if (ts.tv_nsec < 0)
  47         {
  48           ts.tv_nsec += 1000000000;
  49           --ts.tv_sec;
  50         }
  51
  52       if (ts.tv_sec < 0)
  53         return ETIMEDOUT;
  54
  55       tsp = &ts;
  56     }
  57
  58   /* If *futex == val, wait until woken or timeout.  */
  59   lll_futex_timed_wait (futex, val, tsp, private);
  60
  61   return 0;
  62 }