| /* Copyright (C) 2003-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Martin Schwidefsky <schwidefsky@de.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 <endian.h> |
| #include <errno.h> |
| #include <sysdep.h> |
| #include <lowlevellock.h> |
| #include <pthread.h> |
| #include <pthreadP.h> |
| #include <kernel-features.h> |
| |
| #include <shlib-compat.h> |
| |
| #ifndef HAVE_CLOCK_GETTIME_VSYSCALL |
| # undef INTERNAL_VSYSCALL |
| # define INTERNAL_VSYSCALL INTERNAL_SYSCALL |
| # undef INLINE_VSYSCALL |
| # define INLINE_VSYSCALL INLINE_SYSCALL |
| #else |
| # include <bits/libc-vdso.h> |
| #endif |
| |
| /* Cleanup handler, defined in pthread_cond_wait.c. */ |
| extern void __condvar_cleanup (void *arg) |
| __attribute__ ((visibility ("hidden"))); |
| |
| struct _condvar_cleanup_buffer |
| { |
| int oldtype; |
| pthread_cond_t *cond; |
| pthread_mutex_t *mutex; |
| unsigned int bc_seq; |
| }; |
| |
| int |
| __pthread_cond_timedwait (cond, mutex, abstime) |
| pthread_cond_t *cond; |
| pthread_mutex_t *mutex; |
| const struct timespec *abstime; |
| { |
| struct _pthread_cleanup_buffer buffer; |
| struct _condvar_cleanup_buffer cbuffer; |
| int result = 0; |
| |
| /* Catch invalid parameters. */ |
| if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) |
| return EINVAL; |
| |
| int pshared = (cond->__data.__mutex == (void *) ~0l) |
| ? LLL_SHARED : LLL_PRIVATE; |
| |
| #if (defined lll_futex_timed_wait_requeue_pi \ |
| && defined __ASSUME_REQUEUE_PI) |
| int pi_flag = 0; |
| #endif |
| |
| /* Make sure we are alone. */ |
| lll_lock (cond->__data.__lock, pshared); |
| |
| /* Now we can release the mutex. */ |
| int err = __pthread_mutex_unlock_usercnt (mutex, 0); |
| if (err) |
| { |
| lll_unlock (cond->__data.__lock, pshared); |
| return err; |
| } |
| |
| /* We have one new user of the condvar. */ |
| ++cond->__data.__total_seq; |
| ++cond->__data.__futex; |
| cond->__data.__nwaiters += 1 << COND_NWAITERS_SHIFT; |
| |
| /* Work around the fact that the kernel rejects negative timeout values |
| despite them being valid. */ |
| if (__builtin_expect (abstime->tv_sec < 0, 0)) |
| goto timeout; |
| |
| /* Remember the mutex we are using here. If there is already a |
| different address store this is a bad user bug. Do not store |
| anything for pshared condvars. */ |
| if (cond->__data.__mutex != (void *) ~0l) |
| cond->__data.__mutex = mutex; |
| |
| /* Prepare structure passed to cancellation handler. */ |
| cbuffer.cond = cond; |
| cbuffer.mutex = mutex; |
| |
| /* Before we block we enable cancellation. Therefore we have to |
| install a cancellation handler. */ |
| __pthread_cleanup_push (&buffer, __condvar_cleanup, &cbuffer); |
| |
| /* The current values of the wakeup counter. The "woken" counter |
| must exceed this value. */ |
| unsigned long long int val; |
| unsigned long long int seq; |
| val = seq = cond->__data.__wakeup_seq; |
| /* Remember the broadcast counter. */ |
| cbuffer.bc_seq = cond->__data.__broadcast_seq; |
| |
| while (1) |
| { |
| #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \ |
| || !defined lll_futex_timed_wait_bitset) |
| struct timespec rt; |
| { |
| # ifdef __NR_clock_gettime |
| INTERNAL_SYSCALL_DECL (err); |
| (void) INTERNAL_VSYSCALL (clock_gettime, err, 2, |
| (cond->__data.__nwaiters |
| & ((1 << COND_NWAITERS_SHIFT) - 1)), |
| &rt); |
| /* Convert the absolute timeout value to a relative timeout. */ |
| rt.tv_sec = abstime->tv_sec - rt.tv_sec; |
| rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec; |
| # else |
| /* Get the current time. So far we support only one clock. */ |
| struct timeval tv; |
| (void) gettimeofday (&tv, NULL); |
| |
| /* Convert the absolute timeout value to a relative timeout. */ |
| rt.tv_sec = abstime->tv_sec - tv.tv_sec; |
| rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; |
| # endif |
| } |
| if (rt.tv_nsec < 0) |
| { |
| rt.tv_nsec += 1000000000; |
| --rt.tv_sec; |
| } |
| /* Did we already time out? */ |
| if (__builtin_expect (rt.tv_sec < 0, 0)) |
| { |
| if (cbuffer.bc_seq != cond->__data.__broadcast_seq) |
| goto bc_out; |
| |
| goto timeout; |
| } |
| #endif |
| |
| unsigned int futex_val = cond->__data.__futex; |
| |
| /* Prepare to wait. Release the condvar futex. */ |
| lll_unlock (cond->__data.__lock, pshared); |
| |
| /* Enable asynchronous cancellation. Required by the standard. */ |
| cbuffer.oldtype = __pthread_enable_asynccancel (); |
| |
| /* REQUEUE_PI was implemented after FUTEX_CLOCK_REALTIME, so it is sufficient |
| to check just the former. */ |
| #if (defined lll_futex_timed_wait_requeue_pi \ |
| && defined __ASSUME_REQUEUE_PI) |
| /* If pi_flag remained 1 then it means that we had the lock and the mutex |
| but a spurious waker raced ahead of us. Give back the mutex before |
| going into wait again. */ |
| if (pi_flag) |
| { |
| __pthread_mutex_cond_lock_adjust (mutex); |
| __pthread_mutex_unlock_usercnt (mutex, 0); |
| } |
| pi_flag = USE_REQUEUE_PI (mutex); |
| |
| if (pi_flag) |
| { |
| unsigned int clockbit = (cond->__data.__nwaiters & 1 |
| ? 0 : FUTEX_CLOCK_REALTIME); |
| err = lll_futex_timed_wait_requeue_pi (&cond->__data.__futex, |
| futex_val, abstime, clockbit, |
| &mutex->__data.__lock, |
| pshared); |
| pi_flag = (err == 0); |
| } |
| else |
| #endif |
| |
| { |
| #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \ |
| || !defined lll_futex_timed_wait_bitset) |
| /* Wait until woken by signal or broadcast. */ |
| err = lll_futex_timed_wait (&cond->__data.__futex, |
| futex_val, &rt, pshared); |
| #else |
| unsigned int clockbit = (cond->__data.__nwaiters & 1 |
| ? 0 : FUTEX_CLOCK_REALTIME); |
| err = lll_futex_timed_wait_bitset (&cond->__data.__futex, futex_val, |
| abstime, clockbit, pshared); |
| #endif |
| } |
| |
| /* Disable asynchronous cancellation. */ |
| __pthread_disable_asynccancel (cbuffer.oldtype); |
| |
| /* We are going to look at shared data again, so get the lock. */ |
| lll_lock (cond->__data.__lock, pshared); |
| |
| /* If a broadcast happened, we are done. */ |
| if (cbuffer.bc_seq != cond->__data.__broadcast_seq) |
| goto bc_out; |
| |
| /* Check whether we are eligible for wakeup. */ |
| val = cond->__data.__wakeup_seq; |
| if (val != seq && cond->__data.__woken_seq != val) |
| break; |
| |
| /* Not woken yet. Maybe the time expired? */ |
| if (__builtin_expect (err == -ETIMEDOUT, 0)) |
| { |
| timeout: |
| /* Yep. Adjust the counters. */ |
| ++cond->__data.__wakeup_seq; |
| ++cond->__data.__futex; |
| |
| /* The error value. */ |
| result = ETIMEDOUT; |
| break; |
| } |
| } |
| |
| /* Another thread woken up. */ |
| ++cond->__data.__woken_seq; |
| |
| bc_out: |
| |
| cond->__data.__nwaiters -= 1 << COND_NWAITERS_SHIFT; |
| |
| /* If pthread_cond_destroy was called on this variable already, |
| notify the pthread_cond_destroy caller all waiters have left |
| and it can be successfully destroyed. */ |
| if (cond->__data.__total_seq == -1ULL |
| && cond->__data.__nwaiters < (1 << COND_NWAITERS_SHIFT)) |
| lll_futex_wake (&cond->__data.__nwaiters, 1, pshared); |
| |
| /* We are done with the condvar. */ |
| lll_unlock (cond->__data.__lock, pshared); |
| |
| /* The cancellation handling is back to normal, remove the handler. */ |
| __pthread_cleanup_pop (&buffer, 0); |
| |
| /* Get the mutex before returning. */ |
| #if (defined lll_futex_timed_wait_requeue_pi \ |
| && defined __ASSUME_REQUEUE_PI) |
| if (pi_flag) |
| { |
| __pthread_mutex_cond_lock_adjust (mutex); |
| err = 0; |
| } |
| else |
| #endif |
| err = __pthread_mutex_cond_lock (mutex); |
| |
| return err ?: result; |
| } |
| |
| versioned_symbol (libpthread, __pthread_cond_timedwait, pthread_cond_timedwait, |
| GLIBC_2_3_2); |