/* Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Martin Schwidefsky , 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 . */ #include #include #include #include #include #include #include /* 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 attribute_protected __pthread_cond_timedwait ( 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; /* Make sure we are along. */ 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; /* 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) { struct timespec rt; { #ifdef __NR_clock_gettime INTERNAL_SYSCALL_DECL (err); # ifndef __ASSUME_POSIX_TIMERS int ret = # endif INTERNAL_SYSCALL (clock_gettime, err, 2, (cond->__data.__nwaiters & ((1 << COND_NWAITERS_SHIFT) - 1)), &rt); # ifndef __ASSUME_POSIX_TIMERS if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (ret, err), 0)) { 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; } else # endif { /* 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; } 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 (); /* Wait until woken by signal or broadcast. */ err = lll_futex_timed_wait (&cond->__data.__futex, futex_val, &rt, pshared); /* 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. */ err = __pthread_mutex_cond_lock (mutex); return err ?: result; } weak_alias(__pthread_cond_timedwait, pthread_cond_timedwait)