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authorPaolo Bonzini <pbonzini@redhat.com>2012-11-02 15:43:21 +0100
committerAnthony Liguori <aliguori@us.ibm.com>2012-11-02 13:07:54 -0500
commitc166cb72f1676855816340666c3b618beef4b976 (patch)
tree25fb0c400c873eec5e3c9f4c3021c9a9d025b511 /qemu-thread-posix.c
parent1f001dc7bc9e435bf231a5b0edcad1c7c2bd6214 (diff)
downloadhqemu-c166cb72f1676855816340666c3b618beef4b976.zip
hqemu-c166cb72f1676855816340666c3b618beef4b976.tar.gz
semaphore: implement fallback counting semaphores with mutex+condvar
OpenBSD and Darwin do not have sem_timedwait. Implement a fallback for them. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'qemu-thread-posix.c')
-rw-r--r--qemu-thread-posix.c92
1 files changed, 82 insertions, 10 deletions
diff --git a/qemu-thread-posix.c b/qemu-thread-posix.c
index 6a3d3a1..4ef9c7b 100644
--- a/qemu-thread-posix.c
+++ b/qemu-thread-posix.c
@@ -122,36 +122,106 @@ void qemu_sem_init(QemuSemaphore *sem, int init)
{
int rc;
+#if defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
+ rc = pthread_mutex_init(&sem->lock, NULL);
+ if (rc != 0) {
+ error_exit(rc, __func__);
+ }
+ rc = pthread_cond_init(&sem->cond, NULL);
+ if (rc != 0) {
+ error_exit(rc, __func__);
+ }
+ if (init < 0) {
+ error_exit(EINVAL, __func__);
+ }
+ sem->count = init;
+#else
rc = sem_init(&sem->sem, 0, init);
if (rc < 0) {
error_exit(errno, __func__);
}
+#endif
}
void qemu_sem_destroy(QemuSemaphore *sem)
{
int rc;
+#if defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
+ rc = pthread_cond_destroy(&sem->cond);
+ if (rc < 0) {
+ error_exit(rc, __func__);
+ }
+ rc = pthread_mutex_destroy(&sem->lock);
+ if (rc < 0) {
+ error_exit(rc, __func__);
+ }
+#else
rc = sem_destroy(&sem->sem);
if (rc < 0) {
error_exit(errno, __func__);
}
+#endif
}
void qemu_sem_post(QemuSemaphore *sem)
{
int rc;
+#if defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
+ pthread_mutex_lock(&sem->lock);
+ if (sem->count == INT_MAX) {
+ rc = EINVAL;
+ } else if (sem->count++ < 0) {
+ rc = pthread_cond_signal(&sem->cond);
+ } else {
+ rc = 0;
+ }
+ pthread_mutex_unlock(&sem->lock);
+ if (rc != 0) {
+ error_exit(rc, __func__);
+ }
+#else
rc = sem_post(&sem->sem);
if (rc < 0) {
error_exit(errno, __func__);
}
+#endif
+}
+
+static void compute_abs_deadline(struct timespec *ts, int ms)
+{
+ struct timeval tv;
+ gettimeofday(&tv, NULL);
+ ts->tv_nsec = tv.tv_usec * 1000 + (ms % 1000) * 1000000;
+ ts->tv_sec = tv.tv_sec + ms / 1000;
+ if (ts->tv_nsec >= 1000000000) {
+ ts->tv_sec++;
+ ts->tv_nsec -= 1000000000;
+ }
}
int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
{
int rc;
-
+ struct timespec ts;
+
+#if defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
+ compute_abs_deadline(&ts, ms);
+ pthread_mutex_lock(&sem->lock);
+ --sem->count;
+ while (sem->count < 0) {
+ rc = pthread_cond_timedwait(&sem->cond, &sem->lock, &ts);
+ if (rc == ETIMEDOUT) {
+ break;
+ }
+ if (rc != 0) {
+ error_exit(rc, __func__);
+ }
+ }
+ pthread_mutex_unlock(&sem->lock);
+ return (rc == ETIMEDOUT ? -1 : 0);
+#else
if (ms <= 0) {
/* This is cheaper than sem_timedwait. */
do {
@@ -161,15 +231,7 @@ int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
return -1;
}
} else {
- struct timeval tv;
- struct timespec ts;
- gettimeofday(&tv, NULL);
- ts.tv_nsec = tv.tv_usec * 1000 + (ms % 1000) * 1000000;
- ts.tv_sec = tv.tv_sec + ms / 1000;
- if (ts.tv_nsec >= 1000000000) {
- ts.tv_sec++;
- ts.tv_nsec -= 1000000000;
- }
+ compute_abs_deadline(&ts, ms);
do {
rc = sem_timedwait(&sem->sem, &ts);
} while (rc == -1 && errno == EINTR);
@@ -181,10 +243,19 @@ int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
error_exit(errno, __func__);
}
return 0;
+#endif
}
void qemu_sem_wait(QemuSemaphore *sem)
{
+#if defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
+ pthread_mutex_lock(&sem->lock);
+ --sem->count;
+ while (sem->count < 0) {
+ pthread_cond_wait(&sem->cond, &sem->lock);
+ }
+ pthread_mutex_unlock(&sem->lock);
+#else
int rc;
do {
@@ -193,6 +264,7 @@ void qemu_sem_wait(QemuSemaphore *sem)
if (rc < 0) {
error_exit(errno, __func__);
}
+#endif
}
void qemu_thread_create(QemuThread *thread,
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