1 /* Copyright (C) 2003,2004,2007,2010,2011 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, see
17 <http://www.gnu.org/licenses/>. */
22 #include <lowlevellock.h>
25 #include <kernel-features.h>
27 #include <shlib-compat.h>
29 #ifndef HAVE_CLOCK_GETTIME_VSYSCALL
30 # undef INTERNAL_VSYSCALL
31 # define INTERNAL_VSYSCALL INTERNAL_SYSCALL
32 # undef INLINE_VSYSCALL
33 # define INLINE_VSYSCALL INLINE_SYSCALL
35 # include <bits/libc-vdso.h>
38 /* Cleanup handler, defined in pthread_cond_wait.c. */
39 extern void __condvar_cleanup (void *arg
)
40 __attribute__ ((visibility ("hidden")));
42 struct _condvar_cleanup_buffer
46 pthread_mutex_t
*mutex
;
51 __pthread_cond_timedwait (cond
, mutex
, abstime
)
53 pthread_mutex_t
*mutex
;
54 const struct timespec
*abstime
;
56 struct _pthread_cleanup_buffer buffer
;
57 struct _condvar_cleanup_buffer cbuffer
;
60 /* Catch invalid parameters. */
61 if (abstime
->tv_nsec
< 0 || abstime
->tv_nsec
>= 1000000000)
64 int pshared
= (cond
->__data
.__mutex
== (void *) ~0l)
65 ? LLL_SHARED
: LLL_PRIVATE
;
67 /* Make sure we are alone. */
68 lll_lock (cond
->__data
.__lock
, pshared
);
70 /* Now we can release the mutex. */
71 int err
= __pthread_mutex_unlock_usercnt (mutex
, 0);
74 lll_unlock (cond
->__data
.__lock
, pshared
);
78 /* We have one new user of the condvar. */
79 ++cond
->__data
.__total_seq
;
80 ++cond
->__data
.__futex
;
81 cond
->__data
.__nwaiters
+= 1 << COND_NWAITERS_SHIFT
;
83 /* Remember the mutex we are using here. If there is already a
84 different address store this is a bad user bug. Do not store
85 anything for pshared condvars. */
86 if (cond
->__data
.__mutex
!= (void *) ~0l)
87 cond
->__data
.__mutex
= mutex
;
89 /* Prepare structure passed to cancellation handler. */
91 cbuffer
.mutex
= mutex
;
93 /* Before we block we enable cancellation. Therefore we have to
94 install a cancellation handler. */
95 __pthread_cleanup_push (&buffer
, __condvar_cleanup
, &cbuffer
);
97 /* The current values of the wakeup counter. The "woken" counter
98 must exceed this value. */
99 unsigned long long int val
;
100 unsigned long long int seq
;
101 val
= seq
= cond
->__data
.__wakeup_seq
;
102 /* Remember the broadcast counter. */
103 cbuffer
.bc_seq
= cond
->__data
.__broadcast_seq
;
109 #ifdef __NR_clock_gettime
110 INTERNAL_SYSCALL_DECL (err
);
112 ret
= INTERNAL_VSYSCALL (clock_gettime
, err
, 2,
113 (cond
->__data
.__nwaiters
114 & ((1 << COND_NWAITERS_SHIFT
) - 1)),
116 # ifndef __ASSUME_POSIX_TIMERS
117 if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (ret
, err
), 0))
120 (void) gettimeofday (&tv
, NULL
);
122 /* Convert the absolute timeout value to a relative timeout. */
123 rt
.tv_sec
= abstime
->tv_sec
- tv
.tv_sec
;
124 rt
.tv_nsec
= abstime
->tv_nsec
- tv
.tv_usec
* 1000;
129 /* Convert the absolute timeout value to a relative timeout. */
130 rt
.tv_sec
= abstime
->tv_sec
- rt
.tv_sec
;
131 rt
.tv_nsec
= abstime
->tv_nsec
- rt
.tv_nsec
;
134 /* Get the current time. So far we support only one clock. */
136 (void) gettimeofday (&tv
, NULL
);
138 /* Convert the absolute timeout value to a relative timeout. */
139 rt
.tv_sec
= abstime
->tv_sec
- tv
.tv_sec
;
140 rt
.tv_nsec
= abstime
->tv_nsec
- tv
.tv_usec
* 1000;
145 rt
.tv_nsec
+= 1000000000;
148 /* Did we already time out? */
149 if (__builtin_expect (rt
.tv_sec
< 0, 0))
151 if (cbuffer
.bc_seq
!= cond
->__data
.__broadcast_seq
)
157 unsigned int futex_val
= cond
->__data
.__futex
;
159 /* Prepare to wait. Release the condvar futex. */
160 lll_unlock (cond
->__data
.__lock
, pshared
);
162 /* Enable asynchronous cancellation. Required by the standard. */
163 cbuffer
.oldtype
= __pthread_enable_asynccancel ();
165 /* Wait until woken by signal or broadcast. */
166 err
= lll_futex_timed_wait (&cond
->__data
.__futex
,
167 futex_val
, &rt
, pshared
);
169 /* Disable asynchronous cancellation. */
170 __pthread_disable_asynccancel (cbuffer
.oldtype
);
172 /* We are going to look at shared data again, so get the lock. */
173 lll_lock (cond
->__data
.__lock
, pshared
);
175 /* If a broadcast happened, we are done. */
176 if (cbuffer
.bc_seq
!= cond
->__data
.__broadcast_seq
)
179 /* Check whether we are eligible for wakeup. */
180 val
= cond
->__data
.__wakeup_seq
;
181 if (val
!= seq
&& cond
->__data
.__woken_seq
!= val
)
184 /* Not woken yet. Maybe the time expired? */
185 if (__builtin_expect (err
== -ETIMEDOUT
, 0))
188 /* Yep. Adjust the counters. */
189 ++cond
->__data
.__wakeup_seq
;
190 ++cond
->__data
.__futex
;
192 /* The error value. */
198 /* Another thread woken up. */
199 ++cond
->__data
.__woken_seq
;
203 cond
->__data
.__nwaiters
-= 1 << COND_NWAITERS_SHIFT
;
205 /* If pthread_cond_destroy was called on this variable already,
206 notify the pthread_cond_destroy caller all waiters have left
207 and it can be successfully destroyed. */
208 if (cond
->__data
.__total_seq
== -1ULL
209 && cond
->__data
.__nwaiters
< (1 << COND_NWAITERS_SHIFT
))
210 lll_futex_wake (&cond
->__data
.__nwaiters
, 1, pshared
);
212 /* We are done with the condvar. */
213 lll_unlock (cond
->__data
.__lock
, pshared
);
215 /* The cancellation handling is back to normal, remove the handler. */
216 __pthread_cleanup_pop (&buffer
, 0);
218 /* Get the mutex before returning. */
219 err
= __pthread_mutex_cond_lock (mutex
);
221 return err
?: result
;
224 versioned_symbol (libpthread
, __pthread_cond_timedwait
, pthread_cond_timedwait
,