qemu-thread: add API for joinable threads

Split from Jan's original qemu-thread-posix.c patch.  No semantic change,
just introduce the new API that POSIX and Win32 implementations will
conform to.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

cpus.c

@@ -910,7 +910,8 @@ static void qemu_tcg_init_vcpu(void *_env)
         env->halt_cond = g_malloc0(sizeof(QemuCond));
         qemu_cond_init(env->halt_cond);
         tcg_halt_cond = env->halt_cond;
-        qemu_thread_create(env->thread, qemu_tcg_cpu_thread_fn, env);
+        qemu_thread_create(env->thread, qemu_tcg_cpu_thread_fn, env,
+                           QEMU_THREAD_DETACHED);
         while (env->created == 0) {
             qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex);
         }
@@ -926,7 +927,8 @@ static void qemu_kvm_start_vcpu(CPUState *env)
     env->thread = g_malloc0(sizeof(QemuThread));
     env->halt_cond = g_malloc0(sizeof(QemuCond));
     qemu_cond_init(env->halt_cond);
-    qemu_thread_create(env->thread, qemu_kvm_cpu_thread_fn, env);
+    qemu_thread_create(env->thread, qemu_kvm_cpu_thread_fn, env,
+                       QEMU_THREAD_DETACHED);
     while (env->created == 0) {
         qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex);
     }

hw/ccid-card-emulated.c

@@ -541,8 +541,9 @@ static int emulated_initfn(CCIDCardState *base)
         printf("%s: failed to initialize vcard\n", EMULATED_DEV_NAME);
         return -1;
     }
-    qemu_thread_create(&thread_id, event_thread, card);
-    qemu_thread_create(&thread_id, handle_apdu_thread, card);
+    qemu_thread_create(&thread_id, event_thread, card, QEMU_THREAD_DETACHED);
+    qemu_thread_create(&thread_id, handle_apdu_thread, card,
+                       QEMU_THREAD_DETACHED);
     return 0;
 }
 

qemu-thread-posix.c

@@ -117,13 +117,14 @@ void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex)
 
 void qemu_thread_create(QemuThread *thread,
                        void *(*start_routine)(void*),
-                       void *arg)
+                       void *arg, int mode)
 {
+    sigset_t set, oldset;
     int err;
 
-    /* Leave signal handling to the iothread.  */
-    sigset_t set, oldset;
+    assert(mode == QEMU_THREAD_DETACHED);
 
+    /* Leave signal handling to the iothread.  */
     sigfillset(&set);
     pthread_sigmask(SIG_SETMASK, &set, &oldset);
     err = pthread_create(&thread->thread, NULL, start_routine, arg);

qemu-thread-win32.c

@@ -243,10 +243,12 @@ static inline void qemu_thread_init(void)
 
 void qemu_thread_create(QemuThread *thread,
                        void *(*start_routine)(void *),
-                       void *arg)
+                       void *arg, int mode)
 {
     HANDLE hThread;
 
+    assert(mode == QEMU_THREAD_DETACHED);
+
     struct QemuThreadData *data;
     qemu_thread_init();
     data = g_malloc(sizeof *data);

qemu-thread.h

@@ -13,6 +13,9 @@ typedef struct QemuThread QemuThread;
 #include "qemu-thread-posix.h"
 #endif
 
+#define QEMU_THREAD_JOINABLE 0
+#define QEMU_THREAD_DETACHED 1
+
 void qemu_mutex_init(QemuMutex *mutex);
 void qemu_mutex_destroy(QemuMutex *mutex);
 void qemu_mutex_lock(QemuMutex *mutex);
@@ -35,8 +38,9 @@ void qemu_cond_broadcast(QemuCond *cond);
 void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex);
 
 void qemu_thread_create(QemuThread *thread,
-                       void *(*start_routine)(void*),
-                       void *arg);
+                        void *(*start_routine)(void *),
+                        void *arg, int mode);
+void *qemu_thread_join(QemuThread *thread);
 void qemu_thread_get_self(QemuThread *thread);
 int qemu_thread_is_self(QemuThread *thread);
 void qemu_thread_exit(void *retval);

ui/vnc-jobs-async.c

@@ -318,7 +318,7 @@ void vnc_start_worker_thread(void)
         return ;
 
     q = vnc_queue_init();
-    qemu_thread_create(&q->thread, vnc_worker_thread, q);
+    qemu_thread_create(&q->thread, vnc_worker_thread, q, QEMU_THREAD_DETACHED);
     queue = q; /* Set global queue */
 }