qemu-thread: add QemuSemaphore
The new thread pool will use semaphores instead of condition
variables, because QemuCond does not have qemu_cond_timedwait.
(I also like it more this way).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/qemu-thread-posix.c b/qemu-thread-posix.c
index 8fbabda..6a3d3a1 100644
--- a/qemu-thread-posix.c
+++ b/qemu-thread-posix.c
@@ -17,6 +17,9 @@
#include <signal.h>
#include <stdint.h>
#include <string.h>
+#include <limits.h>
+#include <unistd.h>
+#include <sys/time.h>
#include "qemu-thread.h"
static void error_exit(int err, const char *msg)
@@ -115,6 +118,83 @@
error_exit(err, __func__);
}
+void qemu_sem_init(QemuSemaphore *sem, int init)
+{
+ int rc;
+
+ rc = sem_init(&sem->sem, 0, init);
+ if (rc < 0) {
+ error_exit(errno, __func__);
+ }
+}
+
+void qemu_sem_destroy(QemuSemaphore *sem)
+{
+ int rc;
+
+ rc = sem_destroy(&sem->sem);
+ if (rc < 0) {
+ error_exit(errno, __func__);
+ }
+}
+
+void qemu_sem_post(QemuSemaphore *sem)
+{
+ int rc;
+
+ rc = sem_post(&sem->sem);
+ if (rc < 0) {
+ error_exit(errno, __func__);
+ }
+}
+
+int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
+{
+ int rc;
+
+ if (ms <= 0) {
+ /* This is cheaper than sem_timedwait. */
+ do {
+ rc = sem_trywait(&sem->sem);
+ } while (rc == -1 && errno == EINTR);
+ if (rc == -1 && errno == EAGAIN) {
+ 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;
+ }
+ do {
+ rc = sem_timedwait(&sem->sem, &ts);
+ } while (rc == -1 && errno == EINTR);
+ if (rc == -1 && errno == ETIMEDOUT) {
+ return -1;
+ }
+ }
+ if (rc < 0) {
+ error_exit(errno, __func__);
+ }
+ return 0;
+}
+
+void qemu_sem_wait(QemuSemaphore *sem)
+{
+ int rc;
+
+ do {
+ rc = sem_wait(&sem->sem);
+ } while (rc == -1 && errno == EINTR);
+ if (rc < 0) {
+ error_exit(errno, __func__);
+ }
+}
+
void qemu_thread_create(QemuThread *thread,
void *(*start_routine)(void*),
void *arg, int mode)
