| /* sem_timedwait -- wait on a semaphore. Generic futex-using version. |
| Copyright (C) 2003-2014 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <sysdep.h> |
| #include <lowlevellock.h> |
| #include <internaltypes.h> |
| #include <semaphore.h> |
| |
| #include <pthreadP.h> |
| #include <shlib-compat.h> |
| |
| |
| extern void __sem_wait_cleanup (void *arg) attribute_hidden; |
| |
| /* This is in a seperate function in order to make sure gcc |
| puts the call site into an exception region, and thus the |
| cleanups get properly run. */ |
| static int |
| __attribute__ ((noinline)) |
| do_futex_timed_wait (struct new_sem *isem, struct timespec *rt) |
| { |
| int err, oldtype = __pthread_enable_asynccancel (); |
| |
| err = lll_futex_timed_wait (&isem->value, 0, rt, |
| isem->private ^ FUTEX_PRIVATE_FLAG); |
| |
| __pthread_disable_asynccancel (oldtype); |
| return err; |
| } |
| |
| int |
| sem_timedwait (sem_t *sem, const struct timespec *abstime) |
| { |
| struct new_sem *isem = (struct new_sem *) sem; |
| int err; |
| |
| if (atomic_decrement_if_positive (&isem->value) > 0) |
| return 0; |
| |
| if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) |
| { |
| __set_errno (EINVAL); |
| return -1; |
| } |
| |
| atomic_increment (&isem->nwaiters); |
| |
| pthread_cleanup_push (__sem_wait_cleanup, isem); |
| |
| while (1) |
| { |
| struct timeval tv; |
| struct timespec rt; |
| int sec, nsec; |
| |
| /* Get the current time. */ |
| __gettimeofday (&tv, NULL); |
| |
| /* Compute relative timeout. */ |
| sec = abstime->tv_sec - tv.tv_sec; |
| nsec = abstime->tv_nsec - tv.tv_usec * 1000; |
| if (nsec < 0) |
| { |
| nsec += 1000000000; |
| --sec; |
| } |
| |
| /* Already timed out? */ |
| if (sec < 0) |
| { |
| __set_errno (ETIMEDOUT); |
| err = -1; |
| break; |
| } |
| |
| /* Do wait. */ |
| rt.tv_sec = sec; |
| rt.tv_nsec = nsec; |
| err = do_futex_timed_wait(isem, &rt); |
| if (err != 0 && err != -EWOULDBLOCK) |
| { |
| __set_errno (-err); |
| err = -1; |
| break; |
| } |
| |
| if (atomic_decrement_if_positive (&isem->value) > 0) |
| { |
| err = 0; |
| break; |
| } |
| } |
| |
| pthread_cleanup_pop (0); |
| |
| atomic_decrement (&isem->nwaiters); |
| |
| return err; |
| } |