X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=a6e4ba35c9a68f9dae607d196f6c640f751c2989;hb=7aa76730706e7d053204a6df44d8cd6b05619476;hp=4d437fc58ac14d651825fe71788a1674a4126db1;hpb=eb8bf36110d807a9bcda2cab45a5de0885e99aa7;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 4d437fc5..a6e4ba35 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -188,6 +188,22 @@ extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
 
+/*
+ * Returns the HOME directory path. Caller MUST NOT free(3) the returned
+ * pointer.
+ */
+static
+const char *get_lttng_home_dir(void)
+{
+       const char *val;
+
+       val = (const char *) getenv("LTTNG_HOME");
+       if (val != NULL) {
+               return val;
+       }
+       return (const char *) getenv("HOME");
+}
+
 /*
  * Force a read (imply TLS fixup for dlopen) of TLS variables.
  */
@@ -209,10 +225,12 @@ void print_cmd(int cmd, int handle)
 {
 	const char *cmd_name = "Unknown";
 
-	if (cmd_name_mapping[cmd]) {
+	if (cmd >= 0 && cmd < LTTNG_ARRAY_SIZE(cmd_name_mapping)
+			&& cmd_name_mapping[cmd]) {
 		cmd_name = cmd_name_mapping[cmd];
 	}
-	DBG("Message Received \"%s\", Handle \"%s\" (%d)", cmd_name,
+	DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
+		cmd_name, cmd,
 		lttng_ust_obj_get_name(handle), handle);
 }
 
@@ -230,7 +248,7 @@ int setup_local_apps(void)
 		assert(local_apps.allowed == 0);
 		return 0;
 	}
-	home_dir = (const char *) getenv("HOME");
+	home_dir = get_lttng_home_dir();
 	if (!home_dir) {
 		WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
 		assert(local_apps.allowed == 0);
@@ -625,6 +643,25 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 {
 	int ret;
 
+	if (sock_info->root_handle != -1) {
+		ret = lttng_ust_objd_unref(sock_info->root_handle, 1);
+		if (ret) {
+			ERR("Error unref root handle");
+		}
+		sock_info->root_handle = -1;
+	}
+	sock_info->constructor_sem_posted = 0;
+
+	/*
+	 * wait_shm_mmap, socket and notify socket are used by listener
+	 * threads outside of the ust lock, so we cannot tear them down
+	 * ourselves, because we cannot join on these threads. Leave
+	 * responsibility of cleaning up these resources to the OS
+	 * process exit.
+	 */
+	if (exiting)
+		return;
+
 	if (sock_info->socket != -1) {
 		ret = ustcomm_close_unix_sock(sock_info->socket);
 		if (ret) {
@@ -639,21 +676,7 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 		}
 		sock_info->notify_socket = -1;
 	}
-	if (sock_info->root_handle != -1) {
-		ret = lttng_ust_objd_unref(sock_info->root_handle, 1);
-		if (ret) {
-			ERR("Error unref root handle");
-		}
-		sock_info->root_handle = -1;
-	}
-	sock_info->constructor_sem_posted = 0;
-	/*
-	 * wait_shm_mmap is used by listener threads outside of the
-	 * ust lock, so we cannot tear it down ourselves, because we
-	 * cannot join on these threads. Leave this task to the OS
-	 * process exit.
-	 */
-	if (!exiting && sock_info->wait_shm_mmap) {
+	if (sock_info->wait_shm_mmap) {
 		ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE));
 		if (ret) {
 			ERR("Error unmapping wait shm");
@@ -682,6 +705,30 @@ int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
 	 */
 	wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0);
 	if (wait_shm_fd >= 0) {
+		int32_t tmp_read;
+		ssize_t len;
+		size_t bytes_read = 0;
+
+		/*
+		 * Try to read the fd. If unable to do so, try opening
+		 * it in write mode.
+		 */
+		do {
+			len = read(wait_shm_fd,
+				&((char *) &tmp_read)[bytes_read],
+				sizeof(tmp_read) - bytes_read);
+			if (len > 0) {
+				bytes_read += len;
+			}
+		} while ((len < 0 && errno == EINTR)
+			|| (len > 0 && bytes_read < sizeof(tmp_read)));
+		if (bytes_read != sizeof(tmp_read)) {
+			ret = close(wait_shm_fd);
+			if (ret) {
+				ERR("close wait_shm_fd");
+			}
+			goto open_write;
+		}
 		goto end;
 	} else if (wait_shm_fd < 0 && errno != ENOENT) {
 		/*
@@ -692,9 +739,11 @@ int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
 		ERR("Error opening shm %s", sock_info->wait_shm_path);
 		goto end;
 	}
+
+open_write:
 	/*
-	 * If the open failed because the file did not exist, try
-	 * creating it ourself.
+	 * If the open failed because the file did not exist, or because
+	 * the file was not truncated yet, try creating it ourself.
 	 */
 	URCU_TLS(lttng_ust_nest_count)++;
 	pid = fork();
@@ -889,8 +938,6 @@ void *ust_listener_thread(void *arg)
 {
 	struct sock_info *sock_info = arg;
 	int sock, ret, prev_connect_failed = 0, has_waited = 0;
-	int open_sock[2];
-	int i;
 	long timeout;
 
 	/* Restart trying to connect to the session daemon */
@@ -910,11 +957,6 @@ restart:
 		has_waited = 1;
 		prev_connect_failed = 0;
 	}
-	ust_lock();
-
-	if (lttng_ust_comm_should_quit) {
-		goto quit;
-	}
 
 	if (sock_info->socket != -1) {
 		ret = ustcomm_close_unix_sock(sock_info->socket);
@@ -933,47 +975,40 @@ restart:
 		sock_info->notify_socket = -1;
 	}
 
-	/* Register */
-	for (i = 0; i < 2; i++) {
-		ret = ustcomm_connect_unix_sock(sock_info->sock_path);
-		if (ret < 0) {
-			DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
-			prev_connect_failed = 1;
-			/*
-			 * If we cannot find the sessiond daemon, don't delay
-			 * constructor execution.
-			 */
-			ret = handle_register_done(sock_info);
-			assert(!ret);
-			ust_unlock();
-			goto restart;
-		}
-		open_sock[i] = ret;
-	}
+	/*
+	 * Register. We need to perform both connect and sending
+	 * registration message before doing the next connect otherwise
+	 * we may reach unix socket connect queue max limits and block
+	 * on the 2nd connect while the session daemon is awaiting the
+	 * first connect registration message.
+	 */
+	/* Connect cmd socket */
+	ret = ustcomm_connect_unix_sock(sock_info->sock_path);
+	if (ret < 0) {
+		DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
+		prev_connect_failed = 1;
 
-	sock_info->socket = open_sock[0];
-	sock_info->notify_socket = open_sock[1];
+		ust_lock();
+
+		if (lttng_ust_comm_should_quit) {
+			goto quit;
+		}
 
-	timeout = get_notify_sock_timeout();
-	if (timeout >= 0) {
 		/*
-		 * Give at least 10ms to sessiond to reply to
-		 * notifications.
+		 * If we cannot find the sessiond daemon, don't delay
+		 * constructor execution.
 		 */
-		if (timeout < 10)
-			timeout = 10;
-		ret = ustcomm_setsockopt_rcv_timeout(sock_info->notify_socket,
-				timeout);
-		if (ret < 0) {
-			WARN("Error setting socket receive timeout");
-		}
-		ret = ustcomm_setsockopt_snd_timeout(sock_info->notify_socket,
-				timeout);
-		if (ret < 0) {
-			WARN("Error setting socket send timeout");
-		}
-	} else if (timeout < -1) {
-		WARN("Unsuppoorted timeout value %ld", timeout);
+		ret = handle_register_done(sock_info);
+		assert(!ret);
+		ust_unlock();
+		goto restart;
+	}
+	sock_info->socket = ret;
+
+	ust_lock();
+
+	if (lttng_ust_comm_should_quit) {
+		goto quit;
 	}
 
 	/*
@@ -1004,6 +1039,60 @@ restart:
 		ust_unlock();
 		goto restart;
 	}
+
+	ust_unlock();
+
+	/* Connect notify socket */
+	ret = ustcomm_connect_unix_sock(sock_info->sock_path);
+	if (ret < 0) {
+		DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
+		prev_connect_failed = 1;
+
+		ust_lock();
+
+		if (lttng_ust_comm_should_quit) {
+			goto quit;
+		}
+
+		/*
+		 * If we cannot find the sessiond daemon, don't delay
+		 * constructor execution.
+		 */
+		ret = handle_register_done(sock_info);
+		assert(!ret);
+		ust_unlock();
+		goto restart;
+	}
+	sock_info->notify_socket = ret;
+
+	timeout = get_notify_sock_timeout();
+	if (timeout >= 0) {
+		/*
+		 * Give at least 10ms to sessiond to reply to
+		 * notifications.
+		 */
+		if (timeout < 10)
+			timeout = 10;
+		ret = ustcomm_setsockopt_rcv_timeout(sock_info->notify_socket,
+				timeout);
+		if (ret < 0) {
+			WARN("Error setting socket receive timeout");
+		}
+		ret = ustcomm_setsockopt_snd_timeout(sock_info->notify_socket,
+				timeout);
+		if (ret < 0) {
+			WARN("Error setting socket send timeout");
+		}
+	} else if (timeout < -1) {
+		WARN("Unsupported timeout value %ld", timeout);
+	}
+
+	ust_lock();
+
+	if (lttng_ust_comm_should_quit) {
+		goto quit;
+	}
+
 	ret = register_to_sessiond(sock_info->notify_socket,
 			USTCTL_SOCKET_NOTIFY);
 	if (ret < 0) {