1 /* Copyright (C) 2003, 2004 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>
27 #include <shlib-compat.h>
30 /* Cleanup handler, defined in pthread_cond_wait.c. */
31 extern void __condvar_cleanup (void *arg
)
32 __attribute__ ((visibility ("hidden")));
34 struct _condvar_cleanup_buffer
38 pthread_mutex_t
*mutex
;
43 __pthread_cond_timedwait (cond
, mutex
, abstime
)
45 pthread_mutex_t
*mutex
;
46 const struct timespec
*abstime
;
48 struct _pthread_cleanup_buffer buffer
;
49 struct _condvar_cleanup_buffer cbuffer
;
52 /* Catch invalid parameters. */
53 if (abstime
->tv_nsec
< 0 || abstime
->tv_nsec
>= 1000000000)
56 /* Make sure we are along. */
57 lll_mutex_lock (cond
->__data
.__lock
);
59 /* Now we can release the mutex. */
60 int err
= __pthread_mutex_unlock_usercnt (mutex
, 0);
63 lll_mutex_unlock (cond
->__data
.__lock
);
67 /* We have one new user of the condvar. */
68 ++cond
->__data
.__total_seq
;
69 ++cond
->__data
.__futex
;
70 cond
->__data
.__nwaiters
+= 1 << COND_CLOCK_BITS
;
72 /* Remember the mutex we are using here. If there is already a
73 different address store this is a bad user bug. Do not store
74 anything for pshared condvars. */
75 if (cond
->__data
.__mutex
!= (void *) ~0l)
76 cond
->__data
.__mutex
= mutex
;
78 /* Prepare structure passed to cancellation handler. */
80 cbuffer
.mutex
= mutex
;
82 /* Before we block we enable cancellation. Therefore we have to
83 install a cancellation handler. */
84 __pthread_cleanup_push (&buffer
, __condvar_cleanup
, &cbuffer
);
86 /* The current values of the wakeup counter. The "woken" counter
87 must exceed this value. */
88 unsigned long long int val
;
89 unsigned long long int seq
;
90 val
= seq
= cond
->__data
.__wakeup_seq
;
91 /* Remember the broadcast counter. */
92 cbuffer
.bc_seq
= cond
->__data
.__broadcast_seq
;
98 #ifdef __NR_clock_gettime
99 INTERNAL_SYSCALL_DECL (err
);
101 ret
= INTERNAL_SYSCALL (clock_gettime
, err
, 2,
102 (cond
->__data
.__nwaiters
103 & ((1 << COND_CLOCK_BITS
) - 1)),
105 # ifndef __ASSUME_POSIX_TIMERS
106 if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (ret
, err
), 0))
109 (void) gettimeofday (&tv
, NULL
);
111 /* Convert the absolute timeout value to a relative timeout. */
112 rt
.tv_sec
= abstime
->tv_sec
- tv
.tv_sec
;
113 rt
.tv_nsec
= abstime
->tv_nsec
- tv
.tv_usec
* 1000;
118 /* Convert the absolute timeout value to a relative timeout. */
119 rt
.tv_sec
= abstime
->tv_sec
- rt
.tv_sec
;
120 rt
.tv_nsec
= abstime
->tv_nsec
- rt
.tv_nsec
;
123 /* Get the current time. So far we support only one clock. */
125 (void) gettimeofday (&tv
, NULL
);
127 /* Convert the absolute timeout value to a relative timeout. */
128 rt
.tv_sec
= abstime
->tv_sec
- tv
.tv_sec
;
129 rt
.tv_nsec
= abstime
->tv_nsec
- tv
.tv_usec
* 1000;
134 rt
.tv_nsec
+= 1000000000;
137 /* Did we already time out? */
138 if (__builtin_expect (rt
.tv_sec
< 0, 0))
140 if (cbuffer
.bc_seq
!= cond
->__data
.__broadcast_seq
)
146 unsigned int futex_val
= cond
->__data
.__futex
;
148 /* Prepare to wait. Release the condvar futex. */
149 lll_mutex_unlock (cond
->__data
.__lock
);
151 /* Enable asynchronous cancellation. Required by the standard. */
152 cbuffer
.oldtype
= __pthread_enable_asynccancel ();
154 /* Wait until woken by signal or broadcast. */
155 err
= lll_futex_timed_wait (&cond
->__data
.__futex
,
158 /* Disable asynchronous cancellation. */
159 __pthread_disable_asynccancel (cbuffer
.oldtype
);
161 /* We are going to look at shared data again, so get the lock. */
162 lll_mutex_lock(cond
->__data
.__lock
);
164 /* If a broadcast happened, we are done. */
165 if (cbuffer
.bc_seq
!= cond
->__data
.__broadcast_seq
)
168 /* Check whether we are eligible for wakeup. */
169 val
= cond
->__data
.__wakeup_seq
;
170 if (val
!= seq
&& cond
->__data
.__woken_seq
!= val
)
173 /* Not woken yet. Maybe the time expired? */
174 if (__builtin_expect (err
== -ETIMEDOUT
, 0))
177 /* Yep. Adjust the counters. */
178 ++cond
->__data
.__wakeup_seq
;
179 ++cond
->__data
.__futex
;
181 /* The error value. */
187 /* Another thread woken up. */
188 ++cond
->__data
.__woken_seq
;
192 cond
->__data
.__nwaiters
-= 1 << COND_CLOCK_BITS
;
194 /* If pthread_cond_destroy was called on this variable already,
195 notify the pthread_cond_destroy caller all waiters have left
196 and it can be successfully destroyed. */
197 if (cond
->__data
.__total_seq
== -1ULL
198 && cond
->__data
.__nwaiters
< (1 << COND_CLOCK_BITS
))
199 lll_futex_wake (&cond
->__data
.__nwaiters
, 1);
201 /* We are done with the condvar. */
202 lll_mutex_unlock (cond
->__data
.__lock
);
204 /* The cancellation handling is back to normal, remove the handler. */
205 __pthread_cleanup_pop (&buffer
, 0);
207 /* Get the mutex before returning. */
208 err
= __pthread_mutex_cond_lock (mutex
);
210 return err
?: result
;
213 versioned_symbol (libpthread
, __pthread_cond_timedwait
, pthread_cond_timedwait
,