Wait for the destruction of sessions before tearing down main thread

[lttng-tools.git] / src / bin / lttng-sessiond / thread-utils.c

diff --git a/src/bin/lttng-sessiond/thread-utils.c b/src/bin/lttng-sessiond/thread-utils.c
index 99b8298983fa6a7a8f489bcb7222a198b6d217dc..3a8ddb3303639f75d86be3e1b7da7a232d2771ec 100644 (file)
--- a/src/bin/lttng-sessiond/thread-utils.c
+++ b/src/bin/lttng-sessiond/thread-utils.c
@@ -20,6 +20,9 @@
 #include "lttng-sessiond.h"
 #include "utils.h"
 #include <common/utils.h>
+#include <pthread.h>
+
+#define USEC_PER_SEC 1000000
 
 /*
  * Quit pipe for all threads. This permits a single cancellation point
@@ -27,6 +30,19 @@
  */
 static int thread_quit_pipe[2] = { -1, -1 };
 
+/*
+ * Allows threads to query the state of the client thread.
+ */
+static struct client_thread_state {
+       pthread_cond_t cond;
+       pthread_mutex_t lock;
+       bool is_running;
+} client_thread_state = {
+       .cond = PTHREAD_COND_INITIALIZER,
+       .lock = PTHREAD_MUTEX_INITIALIZER,
+       .is_running = false
+};
+
 /*
  * Init thread quit pipe.
  *
@@ -67,6 +83,8 @@ int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
 /*
  * Wait for a notification on the quit pipe (with a timeout).
  *
+ * A timeout value of -1U means no timeout.
+ *
  * Returns 1 if the caller should quit, 0 if the timeout was reached, and
  * -1 if an error was encountered.
  */
@@ -79,11 +97,12 @@ int sessiond_wait_for_quit_pipe(unsigned int timeout_us)
        FD_ZERO(&read_fds);
        FD_SET(thread_quit_pipe[0], &read_fds);
        memset(&timeout, 0, sizeof(timeout));
-       timeout.tv_usec = timeout_us;
+       timeout.tv_sec = timeout_us / USEC_PER_SEC;
+       timeout.tv_usec = timeout_us % USEC_PER_SEC;
 
        while (true) {
                ret = select(thread_quit_pipe[0] + 1, &read_fds, NULL, NULL,
-                               &timeout);
+                               timeout_us != -1U ? &timeout : NULL);
                if (ret < 0 && errno == EINTR) {
                        /* Retry on interrupt. */
                        continue;
@@ -117,6 +136,24 @@ void sessiond_close_quit_pipe(void)
        utils_close_pipe(thread_quit_pipe);
 }
 
+void sessiond_set_client_thread_state(bool running)
+{
+       pthread_mutex_lock(&client_thread_state.lock);
+       client_thread_state.is_running = running;
+       pthread_cond_broadcast(&client_thread_state.cond);
+       pthread_mutex_unlock(&client_thread_state.lock);
+}
+
+void sessiond_wait_client_thread_stopped(void)
+{
+       pthread_mutex_lock(&client_thread_state.lock);
+       while (client_thread_state.is_running) {
+               pthread_cond_wait(&client_thread_state.cond,
+                               &client_thread_state.lock);
+       }
+       pthread_mutex_unlock(&client_thread_state.lock);
+}
+
 static
 int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
                int *a_pipe)