lib/libthr/thread/thr_cond.c

   1 /*
   2  * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #include "namespace.h"
  30 #include <stdlib.h>
  31 #include <errno.h>
  32 #include <string.h>
  33 #include <pthread.h>
  34 #include <limits.h>
  35 #include "un-namespace.h"
  36
  37 #include "thr_private.h"
  38
  39 /*
  40  * Prototypes
  41  */
  42 int     __pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex);
  43 int     __pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
  44                        const struct timespec * abstime);
  45 static int cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr);
  46 static int cond_wait_common(pthread_cond_t *cond, pthread_mutex_t *mutex,
  47                     const struct timespec *abstime, int cancel);
  48 static int cond_signal_common(pthread_cond_t *cond, int broadcast);
  49
  50 /*
  51  * Double underscore versions are cancellation points.  Single underscore
  52  * versions are not and are provided for libc internal usage (which
  53  * shouldn't introduce cancellation points).
  54  */
  55 __weak_reference(__pthread_cond_wait, pthread_cond_wait);
  56 __weak_reference(__pthread_cond_timedwait, pthread_cond_timedwait);
  57
  58 __weak_reference(_pthread_cond_init, pthread_cond_init);
  59 __weak_reference(_pthread_cond_destroy, pthread_cond_destroy);
  60 __weak_reference(_pthread_cond_signal, pthread_cond_signal);
  61 __weak_reference(_pthread_cond_broadcast, pthread_cond_broadcast);
  62
  63 static int
  64 cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
  65 {
  66         pthread_cond_t  pcond;
  67         int             rval = 0;
  68
  69         if ((pcond = (pthread_cond_t)
  70             calloc(1, sizeof(struct pthread_cond))) == NULL) {
  71                 rval = ENOMEM;
  72         } else {
  73                 /*
  74                  * Initialise the condition variable structure:
  75                  */
  76                 if (cond_attr == NULL || *cond_attr == NULL) {
  77                         pcond->c_pshared = 0;
  78                         pcond->c_clockid = CLOCK_REALTIME;
  79                 } else {
  80                         pcond->c_pshared = (*cond_attr)->c_pshared;
  81                         pcond->c_clockid = (*cond_attr)->c_clockid;
  82                 }
  83                 _thr_umutex_init(&pcond->c_lock);
  84                 *cond = pcond;
  85         }
  86         /* Return the completion status: */
  87         return (rval);
  88 }
  89
  90 static int
  91 init_static(struct pthread *thread, pthread_cond_t *cond)
  92 {
  93         int ret;
  94
  95         THR_LOCK_ACQUIRE(thread, &_cond_static_lock);
  96
  97         if (*cond == NULL)
  98                 ret = cond_init(cond, NULL);
  99         else
 100                 ret = 0;
 101
 102         THR_LOCK_RELEASE(thread, &_cond_static_lock);
 103
 104         return (ret);
 105 }
 106
 107 #define CHECK_AND_INIT_COND                                                     \
 108         if (__predict_false((cv = (*cond)) <= THR_COND_DESTROYED)) {            \
 109                 if (cv == THR_COND_INITIALIZER) {                               \
 110                         int ret;                                                \
 111                         ret = init_static(_get_curthread(), cond);              \
 112                         if (ret)                                                \
 113                                 return (ret);                                   \
 114                 } else if (cv == THR_COND_DESTROYED) {                          \
 115                         return (EINVAL);                                        \
 116                 }                                                               \
 117                 cv = *cond;                                                     \
 118         }
 119
 120 int
 121 _pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
 122 {
 123
 124         *cond = NULL;
 125         return (cond_init(cond, cond_attr));
 126 }
 127
 128 int
 129 _pthread_cond_destroy(pthread_cond_t *cond)
 130 {
 131         struct pthread          *curthread = _get_curthread();
 132         struct pthread_cond     *cv;
 133         int                     rval = 0;
 134
 135         if ((cv = *cond) == THR_COND_INITIALIZER)
 136                 rval = 0;
 137         else if (cv == THR_COND_DESTROYED)
 138                 rval = EINVAL;
 139         else {
 140                 cv = *cond;
 141                 THR_UMUTEX_LOCK(curthread, &cv->c_lock);
 142                 *cond = THR_COND_DESTROYED;
 143                 THR_UMUTEX_UNLOCK(curthread, &cv->c_lock);
 144
 145                 /*
 146                  * Free the memory allocated for the condition
 147                  * variable structure:
 148                  */
 149                 free(cv);
 150         }
 151         return (rval);
 152 }
 153
 154 struct cond_cancel_info
 155 {
 156         pthread_mutex_t *mutex;
 157         pthread_cond_t  *cond;
 158         int             count;
 159 };
 160
 161 static void
 162 cond_cancel_handler(void *arg)
 163 {
 164         struct pthread *curthread = _get_curthread();
 165         struct cond_cancel_info *info = (struct cond_cancel_info *)arg;
 166         pthread_cond_t  cv;
 167
 168         if (info->cond != NULL) {
 169                 cv = *(info->cond);
 170                 THR_UMUTEX_UNLOCK(curthread, &cv->c_lock);
 171         }
 172         _mutex_cv_lock(info->mutex, info->count);
 173 }
 174
 175 static int
 176 cond_wait_common(pthread_cond_t *cond, pthread_mutex_t *mutex,
 177         const struct timespec *abstime, int cancel)
 178 {
 179         struct pthread  *curthread = _get_curthread();
 180         struct timespec ts, ts2, *tsp;
 181         struct cond_cancel_info info;
 182         pthread_cond_t  cv;
 183         int             ret;
 184
 185         /*
 186          * If the condition variable is statically initialized,
 187          * perform the dynamic initialization:
 188          */
 189         CHECK_AND_INIT_COND
 190
 191         cv = *cond;
 192         THR_UMUTEX_LOCK(curthread, &cv->c_lock);
 193         ret = _mutex_cv_unlock(mutex, &info.count);
 194         if (__predict_false(ret != 0)) {
 195                 THR_UMUTEX_UNLOCK(curthread, &cv->c_lock);
 196                 return (ret);
 197         }
 198
 199         info.mutex = mutex;
 200         info.cond  = cond;
 201
 202         if (abstime != NULL) {
 203                 clock_gettime(cv->c_clockid, &ts);
 204                 TIMESPEC_SUB(&ts2, abstime, &ts);
 205                 tsp = &ts2;
 206         } else
 207                 tsp = NULL;
 208
 209         if (cancel) {
 210                 THR_CLEANUP_PUSH(curthread, cond_cancel_handler, &info);
 211                 _thr_cancel_enter_defer(curthread);
 212                 ret = _thr_ucond_wait(&cv->c_kerncv, &cv->c_lock, tsp, 1);
 213                 info.cond = NULL;
 214                 _thr_cancel_leave_defer(curthread, ret);
 215                 THR_CLEANUP_POP(curthread, 0);
 216         } else {
 217                 ret = _thr_ucond_wait(&cv->c_kerncv, &cv->c_lock, tsp, 0);
 218         }
 219         if (ret == EINTR)
 220                 ret = 0;
 221         _mutex_cv_lock(mutex, info.count);
 222         return (ret);
 223 }
 224
 225 int
 226 _pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 227 {
 228
 229         return (cond_wait_common(cond, mutex, NULL, 0));
 230 }
 231
 232 int
 233 __pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 234 {
 235
 236         return (cond_wait_common(cond, mutex, NULL, 1));
 237 }
 238
 239 int
 240 _pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
 241                        const struct timespec * abstime)
 242 {
 243
 244         if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
 245             abstime->tv_nsec >= 1000000000)
 246                 return (EINVAL);
 247
 248         return (cond_wait_common(cond, mutex, abstime, 0));
 249 }
 250
 251 int
 252 __pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
 253                        const struct timespec *abstime)
 254 {
 255
 256         if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
 257             abstime->tv_nsec >= 1000000000)
 258                 return (EINVAL);
 259
 260         return (cond_wait_common(cond, mutex, abstime, 1));
 261 }
 262
 263 static int
 264 cond_signal_common(pthread_cond_t *cond, int broadcast)
 265 {
 266         struct pthread  *curthread = _get_curthread();
 267         pthread_cond_t  cv;
 268         int             ret = 0;
 269
 270         /*
 271          * If the condition variable is statically initialized, perform dynamic
 272          * initialization.
 273          */
 274         CHECK_AND_INIT_COND
 275
 276         THR_UMUTEX_LOCK(curthread, &cv->c_lock);
 277         if (!broadcast)
 278                 ret = _thr_ucond_signal(&cv->c_kerncv);
 279         else
 280                 ret = _thr_ucond_broadcast(&cv->c_kerncv);
 281         THR_UMUTEX_UNLOCK(curthread, &cv->c_lock);
 282         return (ret);
 283 }
 284
 285 int
 286 _pthread_cond_signal(pthread_cond_t * cond)
 287 {
 288
 289         return (cond_signal_common(cond, 0));
 290 }
 291
 292 int
 293 _pthread_cond_broadcast(pthread_cond_t * cond)
 294 {
 295
 296         return (cond_signal_common(cond, 1));
 297 }