qemu-thread-posix.c

   1 /*
   2  * Wrappers around mutex/cond/thread functions
   3  *
   4  * Copyright Red Hat, Inc. 2009
   5  *
   6  * Author:
   7  *  Marcelo Tosatti <mtosatti@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <errno.h>
  16 #include <time.h>
  17 #include <signal.h>
  18 #include <stdint.h>
  19 #include <string.h>
  20 #include <limits.h>
  21 #include <unistd.h>
  22 #include <sys/time.h>
  23 #include "qemu/thread.h"
  24
  25 static void error_exit(int err, const char *msg)
  26 {
  27     fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err));
  28     abort();
  29 }
  30
  31 void qemu_mutex_init(QemuMutex *mutex)
  32 {
  33     int err;
  34     pthread_mutexattr_t mutexattr;
  35
  36     pthread_mutexattr_init(&mutexattr);
  37     pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_ERRORCHECK);
  38     err = pthread_mutex_init(&mutex->lock, &mutexattr);
  39     pthread_mutexattr_destroy(&mutexattr);
  40     if (err)
  41         error_exit(err, __func__);
  42 }
  43
  44 void qemu_mutex_destroy(QemuMutex *mutex)
  45 {
  46     int err;
  47
  48     err = pthread_mutex_destroy(&mutex->lock);
  49     if (err)
  50         error_exit(err, __func__);
  51 }
  52
  53 void qemu_mutex_lock(QemuMutex *mutex)
  54 {
  55     int err;
  56
  57     err = pthread_mutex_lock(&mutex->lock);
  58     if (err)
  59         error_exit(err, __func__);
  60 }
  61
  62 int qemu_mutex_trylock(QemuMutex *mutex)
  63 {
  64     return pthread_mutex_trylock(&mutex->lock);
  65 }
  66
  67 void qemu_mutex_unlock(QemuMutex *mutex)
  68 {
  69     int err;
  70
  71     err = pthread_mutex_unlock(&mutex->lock);
  72     if (err)
  73         error_exit(err, __func__);
  74 }
  75
  76 void qemu_cond_init(QemuCond *cond)
  77 {
  78     int err;
  79
  80     err = pthread_cond_init(&cond->cond, NULL);
  81     if (err)
  82         error_exit(err, __func__);
  83 }
  84
  85 void qemu_cond_destroy(QemuCond *cond)
  86 {
  87     int err;
  88
  89     err = pthread_cond_destroy(&cond->cond);
  90     if (err)
  91         error_exit(err, __func__);
  92 }
  93
  94 void qemu_cond_signal(QemuCond *cond)
  95 {
  96     int err;
  97
  98     err = pthread_cond_signal(&cond->cond);
  99     if (err)
 100         error_exit(err, __func__);
 101 }
 102
 103 void qemu_cond_broadcast(QemuCond *cond)
 104 {
 105     int err;
 106
 107     err = pthread_cond_broadcast(&cond->cond);
 108     if (err)
 109         error_exit(err, __func__);
 110 }
 111
 112 void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex)
 113 {
 114     int err;
 115
 116     err = pthread_cond_wait(&cond->cond, &mutex->lock);
 117     if (err)
 118         error_exit(err, __func__);
 119 }
 120
 121 void qemu_sem_init(QemuSemaphore *sem, int init)
 122 {
 123     int rc;
 124
 125 #if defined(__APPLE__) || defined(__NetBSD__)
 126     rc = pthread_mutex_init(&sem->lock, NULL);
 127     if (rc != 0) {
 128         error_exit(rc, __func__);
 129     }
 130     rc = pthread_cond_init(&sem->cond, NULL);
 131     if (rc != 0) {
 132         error_exit(rc, __func__);
 133     }
 134     if (init < 0) {
 135         error_exit(EINVAL, __func__);
 136     }
 137     sem->count = init;
 138 #else
 139     rc = sem_init(&sem->sem, 0, init);
 140     if (rc < 0) {
 141         error_exit(errno, __func__);
 142     }
 143 #endif
 144 }
 145
 146 void qemu_sem_destroy(QemuSemaphore *sem)
 147 {
 148     int rc;
 149
 150 #if defined(__APPLE__) || defined(__NetBSD__)
 151     rc = pthread_cond_destroy(&sem->cond);
 152     if (rc < 0) {
 153         error_exit(rc, __func__);
 154     }
 155     rc = pthread_mutex_destroy(&sem->lock);
 156     if (rc < 0) {
 157         error_exit(rc, __func__);
 158     }
 159 #else
 160     rc = sem_destroy(&sem->sem);
 161     if (rc < 0) {
 162         error_exit(errno, __func__);
 163     }
 164 #endif
 165 }
 166
 167 void qemu_sem_post(QemuSemaphore *sem)
 168 {
 169     int rc;
 170
 171 #if defined(__APPLE__) || defined(__NetBSD__)
 172     pthread_mutex_lock(&sem->lock);
 173     if (sem->count == INT_MAX) {
 174         rc = EINVAL;
 175     } else if (sem->count++ < 0) {
 176         rc = pthread_cond_signal(&sem->cond);
 177     } else {
 178         rc = 0;
 179     }
 180     pthread_mutex_unlock(&sem->lock);
 181     if (rc != 0) {
 182         error_exit(rc, __func__);
 183     }
 184 #else
 185     rc = sem_post(&sem->sem);
 186     if (rc < 0) {
 187         error_exit(errno, __func__);
 188     }
 189 #endif
 190 }
 191
 192 static void compute_abs_deadline(struct timespec *ts, int ms)
 193 {
 194     struct timeval tv;
 195     gettimeofday(&tv, NULL);
 196     ts->tv_nsec = tv.tv_usec * 1000 + (ms % 1000) * 1000000;
 197     ts->tv_sec = tv.tv_sec + ms / 1000;
 198     if (ts->tv_nsec >= 1000000000) {
 199         ts->tv_sec++;
 200         ts->tv_nsec -= 1000000000;
 201     }
 202 }
 203
 204 int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
 205 {
 206     int rc;
 207     struct timespec ts;
 208
 209 #if defined(__APPLE__) || defined(__NetBSD__)
 210     compute_abs_deadline(&ts, ms);
 211     pthread_mutex_lock(&sem->lock);
 212     --sem->count;
 213     while (sem->count < 0) {
 214         rc = pthread_cond_timedwait(&sem->cond, &sem->lock, &ts);
 215         if (rc == ETIMEDOUT) {
 216             ++sem->count;
 217             break;
 218         }
 219         if (rc != 0) {
 220             error_exit(rc, __func__);
 221         }
 222     }
 223     pthread_mutex_unlock(&sem->lock);
 224     return (rc == ETIMEDOUT ? -1 : 0);
 225 #else
 226     if (ms <= 0) {
 227         /* This is cheaper than sem_timedwait.  */
 228         do {
 229             rc = sem_trywait(&sem->sem);
 230         } while (rc == -1 && errno == EINTR);
 231         if (rc == -1 && errno == EAGAIN) {
 232             return -1;
 233         }
 234     } else {
 235         compute_abs_deadline(&ts, ms);
 236         do {
 237             rc = sem_timedwait(&sem->sem, &ts);
 238         } while (rc == -1 && errno == EINTR);
 239         if (rc == -1 && errno == ETIMEDOUT) {
 240             return -1;
 241         }
 242     }
 243     if (rc < 0) {
 244         error_exit(errno, __func__);
 245     }
 246     return 0;
 247 #endif
 248 }
 249
 250 void qemu_sem_wait(QemuSemaphore *sem)
 251 {
 252 #if defined(__APPLE__) || defined(__NetBSD__)
 253     pthread_mutex_lock(&sem->lock);
 254     --sem->count;
 255     while (sem->count < 0) {
 256         pthread_cond_wait(&sem->cond, &sem->lock);
 257     }
 258     pthread_mutex_unlock(&sem->lock);
 259 #else
 260     int rc;
 261
 262     do {
 263         rc = sem_wait(&sem->sem);
 264     } while (rc == -1 && errno == EINTR);
 265     if (rc < 0) {
 266         error_exit(errno, __func__);
 267     }
 268 #endif
 269 }
 270
 271 void qemu_thread_create(QemuThread *thread,
 272                        void *(*start_routine)(void*),
 273                        void *arg, int mode)
 274 {
 275     sigset_t set, oldset;
 276     int err;
 277     pthread_attr_t attr;
 278
 279     err = pthread_attr_init(&attr);
 280     if (err) {
 281         error_exit(err, __func__);
 282     }
 283     if (mode == QEMU_THREAD_DETACHED) {
 284         err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 285         if (err) {
 286             error_exit(err, __func__);
 287         }
 288     }
 289
 290     /* Leave signal handling to the iothread.  */
 291     sigfillset(&set);
 292     pthread_sigmask(SIG_SETMASK, &set, &oldset);
 293     err = pthread_create(&thread->thread, &attr, start_routine, arg);
 294     if (err)
 295         error_exit(err, __func__);
 296
 297     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 298
 299     pthread_attr_destroy(&attr);
 300 }
 301
 302 void qemu_thread_get_self(QemuThread *thread)
 303 {
 304     thread->thread = pthread_self();
 305 }
 306
 307 bool qemu_thread_is_self(QemuThread *thread)
 308 {
 309    return pthread_equal(pthread_self(), thread->thread);
 310 }
 311
 312 void qemu_thread_exit(void *retval)
 313 {
 314     pthread_exit(retval);
 315 }
 316
 317 void *qemu_thread_join(QemuThread *thread)
 318 {
 319     int err;
 320     void *ret;
 321
 322     err = pthread_join(thread->thread, &ret);
 323     if (err) {
 324         error_exit(err, __func__);
 325     }
 326     return ret;
 327 }