+/*
+ * Return 0 on success, -1 if should quit.
+ * The lock is taken in both cases.
+ * Signal-safe.
+ */
+int ust_lock(void)
+{
+ sigset_t sig_all_blocked, orig_mask;
+ int ret, oldstate;
+
+ ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+ if (ret) {
+ ERR("pthread_setcancelstate: %s", strerror(ret));
+ }
+ if (oldstate != PTHREAD_CANCEL_ENABLE) {
+ ERR("pthread_setcancelstate: unexpected oldstate");
+ }
+ sigfillset(&sig_all_blocked);
+ ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ if (!URCU_TLS(ust_mutex_nest)++)
+ pthread_mutex_lock(&ust_mutex);
+ ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ if (lttng_ust_comm_should_quit) {
+ return -1;
+ } else {
+ return 0;
+ }
+}
+
+/*
+ * ust_lock_nocheck() can be used in constructors/destructors, because
+ * they are already nested within the dynamic loader lock, and therefore
+ * have exclusive access against execution of liblttng-ust destructor.
+ * Signal-safe.
+ */
+void ust_lock_nocheck(void)
+{
+ sigset_t sig_all_blocked, orig_mask;
+ int ret, oldstate;
+
+ ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+ if (ret) {
+ ERR("pthread_setcancelstate: %s", strerror(ret));
+ }
+ if (oldstate != PTHREAD_CANCEL_ENABLE) {
+ ERR("pthread_setcancelstate: unexpected oldstate");
+ }
+ sigfillset(&sig_all_blocked);
+ ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ if (!URCU_TLS(ust_mutex_nest)++)
+ pthread_mutex_lock(&ust_mutex);
+ ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+}
+
+/*
+ * Signal-safe.
+ */
+void ust_unlock(void)
+{
+ sigset_t sig_all_blocked, orig_mask;
+ int ret, oldstate;
+
+ sigfillset(&sig_all_blocked);
+ ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ if (!--URCU_TLS(ust_mutex_nest))
+ pthread_mutex_unlock(&ust_mutex);
+ ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ ret = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
+ if (ret) {
+ ERR("pthread_setcancelstate: %s", strerror(ret));
+ }
+ if (oldstate != PTHREAD_CANCEL_DISABLE) {
+ ERR("pthread_setcancelstate: unexpected oldstate");
+ }
+}
+