Document the locking assumptions of consumerd-relayd socket passing

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

diff --git a/src/bin/lttng-sessiond/consumer.c b/src/bin/lttng-sessiond/consumer.c
index a8c5fb871d9521ba7853ae1019e0ce9e9571c4a7..7c8f4e83093590e61ac4d4e565d8d0bc9ba7b5f1 100644 (file)
--- a/src/bin/lttng-sessiond/consumer.c
+++ b/src/bin/lttng-sessiond/consumer.c
@@ -739,6 +739,7 @@ int consumer_send_fds(struct consumer_socket *sock, int *fds, size_t nb_fd)
        assert(fds);
        assert(sock);
        assert(nb_fd > 0);
+       assert(pthread_mutex_trylock(sock->lock) == EBUSY);
 
        ret = lttcomm_send_fds_unix_sock(*sock->fd_ptr, fds, nb_fd);
        if (ret < 0) {
@@ -763,6 +764,7 @@ int consumer_send_msg(struct consumer_socket *sock,
 
        assert(msg);
        assert(sock);
+       assert(pthread_mutex_trylock(sock->lock) == EBUSY);
 
        ret = consumer_socket_send(sock, msg, sizeof(struct lttcomm_consumer_msg));
        if (ret < 0) {
@@ -985,6 +987,8 @@ error:
 /*
  * Send relayd socket to consumer associated with a session name.
  *
+ * The consumer socket lock must be held by the caller.
+ *
  * On success return positive value. On error, negative value.
  */
 int consumer_send_relayd_socket(struct consumer_socket *consumer_sock,
@@ -1089,7 +1093,11 @@ int consumer_set_subdir(struct consumer_output *consumer,
                goto error;
        }
 
-       strncpy(consumer->subdir, tmp_path, sizeof(consumer->subdir));
+       if (lttng_strncpy(consumer->subdir, tmp_path,
+                       sizeof(consumer->subdir))) {
+               ret = -EINVAL;
+               goto error;
+       }
        DBG2("Consumer subdir set to %s", consumer->subdir);
 
 error:
@@ -1187,6 +1195,38 @@ end:
        return ret;
 }
 
+/*
+ * Send a clear quiescent command to consumer using the given channel key.
+ *
+ * Return 0 on success else a negative value.
+ */
+int consumer_clear_quiescent_channel(struct consumer_socket *socket, uint64_t key)
+{
+       int ret;
+       struct lttcomm_consumer_msg msg;
+
+       assert(socket);
+
+       DBG2("Consumer clear quiescent channel key %" PRIu64, key);
+
+       memset(&msg, 0, sizeof(msg));
+       msg.cmd_type = LTTNG_CONSUMER_CLEAR_QUIESCENT_CHANNEL;
+       msg.u.clear_quiescent_channel.key = key;
+
+       pthread_mutex_lock(socket->lock);
+       health_code_update();
+
+       ret = consumer_send_msg(socket, &msg);
+       if (ret < 0) {
+               goto end;
+       }
+
+end:
+       health_code_update();
+       pthread_mutex_unlock(socket->lock);
+       return ret;
+}
+
 /*
  * Send a close metadata command to consumer using the given channel key.
  * Called with registry lock held.