| /* |
| * Wrappers around mutex/cond/thread functions |
| * |
| * Copyright Red Hat, Inc. 2009 |
| * |
| * Author: |
| * Marcelo Tosatti <mtosatti@redhat.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| * See the COPYING file in the top-level directory. |
| * |
| */ |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <errno.h> |
| #include <time.h> |
| #include <signal.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <limits.h> |
| #include <unistd.h> |
| #include <sys/time.h> |
| #ifdef __linux__ |
| #include <sys/syscall.h> |
| #include <linux/futex.h> |
| #endif |
| #include "qemu/thread.h" |
| #include "qemu/atomic.h" |
| |
| static bool name_threads; |
| |
| void qemu_thread_naming(bool enable) |
| { |
| name_threads = enable; |
| } |
| |
| static void error_exit(int err, const char *msg) |
| { |
| fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err)); |
| abort(); |
| } |
| |
| void qemu_mutex_init(QemuMutex *mutex) |
| { |
| int err; |
| pthread_mutexattr_t mutexattr; |
| |
| pthread_mutexattr_init(&mutexattr); |
| pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_ERRORCHECK); |
| err = pthread_mutex_init(&mutex->lock, &mutexattr); |
| pthread_mutexattr_destroy(&mutexattr); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_mutex_destroy(QemuMutex *mutex) |
| { |
| int err; |
| |
| err = pthread_mutex_destroy(&mutex->lock); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_mutex_lock(QemuMutex *mutex) |
| { |
| int err; |
| |
| err = pthread_mutex_lock(&mutex->lock); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| int qemu_mutex_trylock(QemuMutex *mutex) |
| { |
| return pthread_mutex_trylock(&mutex->lock); |
| } |
| |
| void qemu_mutex_unlock(QemuMutex *mutex) |
| { |
| int err; |
| |
| err = pthread_mutex_unlock(&mutex->lock); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_cond_init(QemuCond *cond) |
| { |
| int err; |
| |
| err = pthread_cond_init(&cond->cond, NULL); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_cond_destroy(QemuCond *cond) |
| { |
| int err; |
| |
| err = pthread_cond_destroy(&cond->cond); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_cond_signal(QemuCond *cond) |
| { |
| int err; |
| |
| err = pthread_cond_signal(&cond->cond); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_cond_broadcast(QemuCond *cond) |
| { |
| int err; |
| |
| err = pthread_cond_broadcast(&cond->cond); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex) |
| { |
| int err; |
| |
| err = pthread_cond_wait(&cond->cond, &mutex->lock); |
| if (err) |
| error_exit(err, __func__); |
| } |
| |
| void qemu_sem_init(QemuSemaphore *sem, int init) |
| { |
| int rc; |
| |
| #if 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(__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(__APPLE__) || defined(__NetBSD__) |
| pthread_mutex_lock(&sem->lock); |
| if (sem->count == UINT_MAX) { |
| rc = EINVAL; |
| } else { |
| sem->count++; |
| rc = pthread_cond_signal(&sem->cond); |
| } |
| 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(__APPLE__) || defined(__NetBSD__) |
| rc = 0; |
| compute_abs_deadline(&ts, ms); |
| pthread_mutex_lock(&sem->lock); |
| while (sem->count == 0) { |
| rc = pthread_cond_timedwait(&sem->cond, &sem->lock, &ts); |
| if (rc == ETIMEDOUT) { |
| break; |
| } |
| if (rc != 0) { |
| error_exit(rc, __func__); |
| } |
| } |
| if (rc != ETIMEDOUT) { |
| --sem->count; |
| } |
| pthread_mutex_unlock(&sem->lock); |
| return (rc == ETIMEDOUT ? -1 : 0); |
| #else |
| 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 { |
| compute_abs_deadline(&ts, ms); |
| 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; |
| #endif |
| } |
| |
| void qemu_sem_wait(QemuSemaphore *sem) |
| { |
| int rc; |
| |
| #if defined(__APPLE__) || defined(__NetBSD__) |
| pthread_mutex_lock(&sem->lock); |
| while (sem->count == 0) { |
| rc = pthread_cond_wait(&sem->cond, &sem->lock); |
| if (rc != 0) { |
| error_exit(rc, __func__); |
| } |
| } |
| --sem->count; |
| pthread_mutex_unlock(&sem->lock); |
| #else |
| do { |
| rc = sem_wait(&sem->sem); |
| } while (rc == -1 && errno == EINTR); |
| if (rc < 0) { |
| error_exit(errno, __func__); |
| } |
| #endif |
| } |
| |
| #ifdef __linux__ |
| #define futex(...) syscall(__NR_futex, __VA_ARGS__) |
| |
| static inline void futex_wake(QemuEvent *ev, int n) |
| { |
| futex(ev, FUTEX_WAKE, n, NULL, NULL, 0); |
| } |
| |
| static inline void futex_wait(QemuEvent *ev, unsigned val) |
| { |
| futex(ev, FUTEX_WAIT, (int) val, NULL, NULL, 0); |
| } |
| #else |
| static inline void futex_wake(QemuEvent *ev, int n) |
| { |
| if (n == 1) { |
| pthread_cond_signal(&ev->cond); |
| } else { |
| pthread_cond_broadcast(&ev->cond); |
| } |
| } |
| |
| static inline void futex_wait(QemuEvent *ev, unsigned val) |
| { |
| pthread_mutex_lock(&ev->lock); |
| if (ev->value == val) { |
| pthread_cond_wait(&ev->cond, &ev->lock); |
| } |
| pthread_mutex_unlock(&ev->lock); |
| } |
| #endif |
| |
| /* Valid transitions: |
| * - free->set, when setting the event |
| * - busy->set, when setting the event, followed by futex_wake |
| * - set->free, when resetting the event |
| * - free->busy, when waiting |
| * |
| * set->busy does not happen (it can be observed from the outside but |
| * it really is set->free->busy). |
| * |
| * busy->free provably cannot happen; to enforce it, the set->free transition |
| * is done with an OR, which becomes a no-op if the event has concurrently |
| * transitioned to free or busy. |
| */ |
| |
| #define EV_SET 0 |
| #define EV_FREE 1 |
| #define EV_BUSY -1 |
| |
| void qemu_event_init(QemuEvent *ev, bool init) |
| { |
| #ifndef __linux__ |
| pthread_mutex_init(&ev->lock, NULL); |
| pthread_cond_init(&ev->cond, NULL); |
| #endif |
| |
| ev->value = (init ? EV_SET : EV_FREE); |
| } |
| |
| void qemu_event_destroy(QemuEvent *ev) |
| { |
| #ifndef __linux__ |
| pthread_mutex_destroy(&ev->lock); |
| pthread_cond_destroy(&ev->cond); |
| #endif |
| } |
| |
| void qemu_event_set(QemuEvent *ev) |
| { |
| if (atomic_mb_read(&ev->value) != EV_SET) { |
| if (atomic_xchg(&ev->value, EV_SET) == EV_BUSY) { |
| /* There were waiters, wake them up. */ |
| futex_wake(ev, INT_MAX); |
| } |
| } |
| } |
| |
| void qemu_event_reset(QemuEvent *ev) |
| { |
| if (atomic_mb_read(&ev->value) == EV_SET) { |
| /* |
| * If there was a concurrent reset (or even reset+wait), |
| * do nothing. Otherwise change EV_SET->EV_FREE. |
| */ |
| atomic_or(&ev->value, EV_FREE); |
| } |
| } |
| |
| void qemu_event_wait(QemuEvent *ev) |
| { |
| unsigned value; |
| |
| value = atomic_mb_read(&ev->value); |
| if (value != EV_SET) { |
| if (value == EV_FREE) { |
| /* |
| * Leave the event reset and tell qemu_event_set that there |
| * are waiters. No need to retry, because there cannot be |
| * a concurent busy->free transition. After the CAS, the |
| * event will be either set or busy. |
| */ |
| if (atomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) { |
| return; |
| } |
| } |
| futex_wait(ev, EV_BUSY); |
| } |
| } |
| |
| void qemu_thread_create(QemuThread *thread, const char *name, |
| void *(*start_routine)(void*), |
| void *arg, int mode) |
| { |
| sigset_t set, oldset; |
| int err; |
| pthread_attr_t attr; |
| |
| err = pthread_attr_init(&attr); |
| if (err) { |
| error_exit(err, __func__); |
| } |
| if (mode == QEMU_THREAD_DETACHED) { |
| err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); |
| if (err) { |
| error_exit(err, __func__); |
| } |
| } |
| |
| /* Leave signal handling to the iothread. */ |
| sigfillset(&set); |
| pthread_sigmask(SIG_SETMASK, &set, &oldset); |
| err = pthread_create(&thread->thread, &attr, start_routine, arg); |
| if (err) |
| error_exit(err, __func__); |
| |
| #ifdef _GNU_SOURCE |
| if (name_threads) { |
| pthread_setname_np(thread->thread, name); |
| } |
| #endif |
| |
| pthread_sigmask(SIG_SETMASK, &oldset, NULL); |
| |
| pthread_attr_destroy(&attr); |
| } |
| |
| void qemu_thread_get_self(QemuThread *thread) |
| { |
| thread->thread = pthread_self(); |
| } |
| |
| bool qemu_thread_is_self(QemuThread *thread) |
| { |
| return pthread_equal(pthread_self(), thread->thread); |
| } |
| |
| void qemu_thread_exit(void *retval) |
| { |
| pthread_exit(retval); |
| } |
| |
| void *qemu_thread_join(QemuThread *thread) |
| { |
| int err; |
| void *ret; |
| |
| err = pthread_join(thread->thread, &ret); |
| if (err) { |
| error_exit(err, __func__); |
| } |
| return ret; |
| } |