Initial import of qemu-2.4.1HEADmaster

1 files changed, 509 insertions, 0 deletions

diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
new file mode 100644
index 00000000..ba67cec6
--- /dev/null
+++ b/util/qemu-thread-posix.c
@@ -0,0 +1,509 @@
+/*
+ * 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"
+#include "qemu/notify.h"
+
+static bool name_threads;
+
+void qemu_thread_naming(bool enable)
+{
+    name_threads = enable;
+
+#ifndef CONFIG_THREAD_SETNAME_BYTHREAD
+    /* This is a debugging option, not fatal */
+    if (enable) {
+        fprintf(stderr, "qemu: thread naming not supported on this host\n");
+    }
+#endif
+}
+
+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;
+
+    err = pthread_mutex_init(&mutex->lock, NULL);
+    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)
+{
+    pthread_mutex_lock(&ev->lock);
+    if (n == 1) {
+        pthread_cond_signal(&ev->cond);
+    } else {
+        pthread_cond_broadcast(&ev->cond);
+    }
+    pthread_mutex_unlock(&ev->lock);
+}
+
+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);
+    }
+}
+
+static pthread_key_t exit_key;
+
+union NotifierThreadData {
+    void *ptr;
+    NotifierList list;
+};
+QEMU_BUILD_BUG_ON(sizeof(union NotifierThreadData) != sizeof(void *));
+
+void qemu_thread_atexit_add(Notifier *notifier)
+{
+    union NotifierThreadData ntd;
+    ntd.ptr = pthread_getspecific(exit_key);
+    notifier_list_add(&ntd.list, notifier);
+    pthread_setspecific(exit_key, ntd.ptr);
+}
+
+void qemu_thread_atexit_remove(Notifier *notifier)
+{
+    union NotifierThreadData ntd;
+    ntd.ptr = pthread_getspecific(exit_key);
+    notifier_remove(notifier);
+    pthread_setspecific(exit_key, ntd.ptr);
+}
+
+static void qemu_thread_atexit_run(void *arg)
+{
+    union NotifierThreadData ntd = { .ptr = arg };
+    notifier_list_notify(&ntd.list, NULL);
+}
+
+static void __attribute__((constructor)) qemu_thread_atexit_init(void)
+{
+    pthread_key_create(&exit_key, qemu_thread_atexit_run);
+}
+
+
+/* Attempt to set the threads name; note that this is for debug, so
+ * we're not going to fail if we can't set it.
+ */
+static void qemu_thread_set_name(QemuThread *thread, const char *name)
+{
+#ifdef CONFIG_PTHREAD_SETNAME_NP
+    pthread_setname_np(thread->thread, name);
+#endif
+}
+
+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__);
+
+    if (name_threads) {
+        qemu_thread_set_name(thread, name);
+    }
+
+    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;
+}