1 /* Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23 #include <lowlevellock.h>
26 #include <kernel-features.h>
28 #include <shlib-compat.h>
31 /* Cleanup handler, defined in pthread_cond_wait.c. */
32 extern void __condvar_cleanup (void *arg)
33 __attribute__ ((visibility ("hidden")));
35 struct _condvar_cleanup_buffer
39 pthread_mutex_t *mutex;
44 __pthread_cond_timedwait (cond, mutex, abstime)
46 pthread_mutex_t *mutex;
47 const struct timespec *abstime;
49 struct _pthread_cleanup_buffer buffer;
50 struct _condvar_cleanup_buffer cbuffer;
53 /* Catch invalid parameters. */
54 if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
57 int pshared = (cond->__data.__mutex == (void *) ~0l)
58 ? LLL_SHARED : LLL_PRIVATE;
60 /* Make sure we are along. */
61 lll_lock (cond->__data.__lock, pshared);
63 /* Now we can release the mutex. */
64 int err = __pthread_mutex_unlock_usercnt (mutex, 0);
67 lll_unlock (cond->__data.__lock, pshared);
71 /* We have one new user of the condvar. */
72 ++cond->__data.__total_seq;
73 ++cond->__data.__futex;
74 cond->__data.__nwaiters += 1 << COND_NWAITERS_SHIFT;
76 /* Remember the mutex we are using here. If there is already a
77 different address store this is a bad user bug. Do not store
78 anything for pshared condvars. */
79 if (cond->__data.__mutex != (void *) ~0l)
80 cond->__data.__mutex = mutex;
82 /* Prepare structure passed to cancellation handler. */
84 cbuffer.mutex = mutex;
86 /* Before we block we enable cancellation. Therefore we have to
87 install a cancellation handler. */
88 __pthread_cleanup_push (&buffer, __condvar_cleanup, &cbuffer);
90 /* The current values of the wakeup counter. The "woken" counter
91 must exceed this value. */
92 unsigned long long int val;
93 unsigned long long int seq;
94 val = seq = cond->__data.__wakeup_seq;
95 /* Remember the broadcast counter. */
96 cbuffer.bc_seq = cond->__data.__broadcast_seq;
102 #ifdef __NR_clock_gettime
103 INTERNAL_SYSCALL_DECL (err);
105 ret = INTERNAL_SYSCALL (clock_gettime, err, 2,
106 (cond->__data.__nwaiters
107 & ((1 << COND_NWAITERS_SHIFT) - 1)),
109 # ifndef __ASSUME_POSIX_TIMERS
110 if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (ret, err), 0))
113 (void) gettimeofday (&tv, NULL);
115 /* Convert the absolute timeout value to a relative timeout. */
116 rt.tv_sec = abstime->tv_sec - tv.tv_sec;
117 rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
122 /* Convert the absolute timeout value to a relative timeout. */
123 rt.tv_sec = abstime->tv_sec - rt.tv_sec;
124 rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec;
127 /* Get the current time. So far we support only one clock. */
129 (void) gettimeofday (&tv, NULL);
131 /* Convert the absolute timeout value to a relative timeout. */
132 rt.tv_sec = abstime->tv_sec - tv.tv_sec;
133 rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
138 rt.tv_nsec += 1000000000;
141 /* Did we already time out? */
142 if (__builtin_expect (rt.tv_sec < 0, 0))
144 if (cbuffer.bc_seq != cond->__data.__broadcast_seq)
150 unsigned int futex_val = cond->__data.__futex;
152 /* Prepare to wait. Release the condvar futex. */
153 lll_unlock (cond->__data.__lock, pshared);
155 /* Enable asynchronous cancellation. Required by the standard. */
156 cbuffer.oldtype = __pthread_enable_asynccancel ();
158 /* Wait until woken by signal or broadcast. */
159 err = lll_futex_timed_wait (&cond->__data.__futex,
160 futex_val, &rt, pshared);
162 /* Disable asynchronous cancellation. */
163 __pthread_disable_asynccancel (cbuffer.oldtype);
165 /* We are going to look at shared data again, so get the lock. */
166 lll_lock (cond->__data.__lock, pshared);
168 /* If a broadcast happened, we are done. */
169 if (cbuffer.bc_seq != cond->__data.__broadcast_seq)
172 /* Check whether we are eligible for wakeup. */
173 val = cond->__data.__wakeup_seq;
174 if (val != seq && cond->__data.__woken_seq != val)
177 /* Not woken yet. Maybe the time expired? */
178 if (__builtin_expect (err == -ETIMEDOUT, 0))
181 /* Yep. Adjust the counters. */
182 ++cond->__data.__wakeup_seq;
183 ++cond->__data.__futex;
185 /* The error value. */
191 /* Another thread woken up. */
192 ++cond->__data.__woken_seq;
196 cond->__data.__nwaiters -= 1 << COND_NWAITERS_SHIFT;
198 /* If pthread_cond_destroy was called on this variable already,
199 notify the pthread_cond_destroy caller all waiters have left
200 and it can be successfully destroyed. */
201 if (cond->__data.__total_seq == -1ULL
202 && cond->__data.__nwaiters < (1 << COND_NWAITERS_SHIFT))
203 lll_futex_wake (&cond->__data.__nwaiters, 1, pshared);
205 /* We are done with the condvar. */
206 lll_unlock (cond->__data.__lock, pshared);
208 /* The cancellation handling is back to normal, remove the handler. */
209 __pthread_cleanup_pop (&buffer, 0);
211 /* Get the mutex before returning. */
212 err = __pthread_mutex_cond_lock (mutex);
214 return err ?: result;
217 versioned_symbol (libpthread, __pthread_cond_timedwait, pthread_cond_timedwait,