Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2019-07-08-1' into...

[mirror_qemu.git] / util / qemu-thread-posix.c

diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
index b789cf32e954cdcc7a290b0cdfa86deb1ee49f66..1bf5e65dea8629d0ddec70ca0935f616f530fa83 100644 (file)
--- a/util/qemu-thread-posix.c
+++ b/util/qemu-thread-posix.c
@@ -14,7 +14,7 @@
 #include "qemu/thread.h"
 #include "qemu/atomic.h"
 #include "qemu/notify.h"
-#include "trace.h"
+#include "qemu-thread-common.h"
 
 static bool name_threads;
 
@@ -43,7 +43,7 @@ void qemu_mutex_init(QemuMutex *mutex)
     err = pthread_mutex_init(&mutex->lock, NULL);
     if (err)
         error_exit(err, __func__);
-    mutex->initialized = true;
+    qemu_mutex_post_init(mutex);
 }
 
 void qemu_mutex_destroy(QemuMutex *mutex)
@@ -62,13 +62,11 @@ void qemu_mutex_lock_impl(QemuMutex *mutex, const char *file, const int line)
     int err;
 
     assert(mutex->initialized);
-    trace_qemu_mutex_lock(mutex, file, line);
-
+    qemu_mutex_pre_lock(mutex, file, line);
     err = pthread_mutex_lock(&mutex->lock);
     if (err)
         error_exit(err, __func__);
-
-    trace_qemu_mutex_locked(mutex, file, line);
+    qemu_mutex_post_lock(mutex, file, line);
 }
 
 int qemu_mutex_trylock_impl(QemuMutex *mutex, const char *file, const int line)
@@ -78,7 +76,7 @@ int qemu_mutex_trylock_impl(QemuMutex *mutex, const char *file, const int line)
     assert(mutex->initialized);
     err = pthread_mutex_trylock(&mutex->lock);
     if (err == 0) {
-        trace_qemu_mutex_locked(mutex, file, line);
+        qemu_mutex_post_lock(mutex, file, line);
         return 0;
     }
     if (err != EBUSY) {
@@ -92,11 +90,10 @@ void qemu_mutex_unlock_impl(QemuMutex *mutex, const char *file, const int line)
     int err;
 
     assert(mutex->initialized);
+    qemu_mutex_pre_unlock(mutex, file, line);
     err = pthread_mutex_unlock(&mutex->lock);
     if (err)
         error_exit(err, __func__);
-
-    trace_qemu_mutex_unlock(mutex, file, line);
 }
 
 void qemu_rec_mutex_init(QemuRecMutex *mutex)
@@ -160,9 +157,9 @@ void qemu_cond_wait_impl(QemuCond *cond, QemuMutex *mutex, const char *file, con
     int err;
 
     assert(cond->initialized);
-    trace_qemu_mutex_unlock(mutex, file, line);
+    qemu_mutex_pre_unlock(mutex, file, line);
     err = pthread_cond_wait(&cond->cond, &mutex->lock);
-    trace_qemu_mutex_locked(mutex, file, line);
+    qemu_mutex_post_lock(mutex, file, line);
     if (err)
         error_exit(err, __func__);
 }
@@ -446,43 +443,34 @@ void qemu_event_wait(QemuEvent *ev)
     }
 }
 
-static pthread_key_t exit_key;
-
-union NotifierThreadData {
-    void *ptr;
-    NotifierList list;
-};
-QEMU_BUILD_BUG_ON(sizeof(union NotifierThreadData) != sizeof(void *));
+static __thread NotifierList thread_exit;
 
+/*
+ * Note that in this implementation you can register a thread-exit
+ * notifier for the main thread, but it will never be called.
+ * This is OK because main thread exit can only happen when the
+ * entire process is exiting, and the API allows notifiers to not
+ * be called on process exit.
+ */
 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);
+    notifier_list_add(&thread_exit, notifier);
 }
 
 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)
+static void qemu_thread_atexit_notify(void *arg)
 {
-    pthread_key_create(&exit_key, qemu_thread_atexit_run);
+    /*
+     * Called when non-main thread exits (via qemu_thread_exit()
+     * or by returning from its start routine.)
+     */
+    notifier_list_notify(&thread_exit, NULL);
 }
 
-
-#ifdef CONFIG_PTHREAD_SETNAME_NP
 typedef struct {
     void *(*start_routine)(void *);
     void *arg;
@@ -494,17 +482,27 @@ static void *qemu_thread_start(void *args)
     QemuThreadArgs *qemu_thread_args = args;
     void *(*start_routine)(void *) = qemu_thread_args->start_routine;
     void *arg = qemu_thread_args->arg;
+    void *r;
 
+#ifdef CONFIG_THREAD_SETNAME_BYTHREAD
     /* 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.
      */
-    pthread_setname_np(pthread_self(), qemu_thread_args->name);
+    if (name_threads && qemu_thread_args->name) {
+# if defined(CONFIG_PTHREAD_SETNAME_NP_W_TID)
+        pthread_setname_np(pthread_self(), qemu_thread_args->name);
+# elif defined(CONFIG_PTHREAD_SETNAME_NP_WO_TID)
+        pthread_setname_np(qemu_thread_args->name);
+# endif
+    }
+#endif
     g_free(qemu_thread_args->name);
     g_free(qemu_thread_args);
-    return start_routine(arg);
+    pthread_cleanup_push(qemu_thread_atexit_notify, NULL);
+    r = start_routine(arg);
+    pthread_cleanup_pop(1);
+    return r;
 }
-#endif
-
 
 void qemu_thread_create(QemuThread *thread, const char *name,
                        void *(*start_routine)(void*),
@@ -513,6 +511,7 @@ void qemu_thread_create(QemuThread *thread, const char *name,
     sigset_t set, oldset;
     int err;
     pthread_attr_t attr;
+    QemuThreadArgs *qemu_thread_args;
 
     err = pthread_attr_init(&attr);
     if (err) {
@@ -525,24 +524,20 @@ void qemu_thread_create(QemuThread *thread, const char *name,
 
     /* Leave signal handling to the iothread.  */
     sigfillset(&set);
+    /* Blocking the signals can result in undefined behaviour. */
+    sigdelset(&set, SIGSEGV);
+    sigdelset(&set, SIGFPE);
+    sigdelset(&set, SIGILL);
+    /* TODO avoid SIGBUS loss on macOS */
     pthread_sigmask(SIG_SETMASK, &set, &oldset);
 
-#ifdef CONFIG_PTHREAD_SETNAME_NP
-    if (name_threads) {
-        QemuThreadArgs *qemu_thread_args;
-        qemu_thread_args = g_new0(QemuThreadArgs, 1);
-        qemu_thread_args->name = g_strdup(name);
-        qemu_thread_args->start_routine = start_routine;
-        qemu_thread_args->arg = arg;
-
-        err = pthread_create(&thread->thread, &attr,
-                             qemu_thread_start, qemu_thread_args);
-    } else
-#endif
-    {
-        err = pthread_create(&thread->thread, &attr,
-                             start_routine, arg);
-    }
+    qemu_thread_args = g_new0(QemuThreadArgs, 1);
+    qemu_thread_args->name = g_strdup(name);
+    qemu_thread_args->start_routine = start_routine;
+    qemu_thread_args->arg = arg;
+
+    err = pthread_create(&thread->thread, &attr,
+                         qemu_thread_start, qemu_thread_args);
 
     if (err)
         error_exit(err, __func__);