Fix: sessiond: client socket not created by the main thread
authorJérémie Galarneau <jeremie.galarneau@efficios.com>
Mon, 7 Oct 2019 22:26:51 +0000 (18:26 -0400)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Mon, 7 Oct 2019 23:33:31 +0000 (19:33 -0400)
The client socket is not created by the session daemon's main thread
which causes calls to umask() to be issued from multiple threads.

Since umask manipulates a process-wide ressource, it should be only be
used by a single thread.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
src/bin/lttng-sessiond/client.c
src/bin/lttng-sessiond/thread.c

index 870277534ec2e1f50dc614b1884f73460f984299..327c1fe1706efabaefdf9dd2a3c5dc7fb4865c3e 100644 (file)
@@ -44,6 +44,7 @@ static bool is_root;
 static struct thread_state {
        sem_t ready;
        bool running;
+       int client_sock;
 } thread_state;
 
 static void set_thread_status(bool running)
@@ -2022,7 +2023,7 @@ static void *thread_manage_clients(void *data)
        uint32_t revents, nb_fd;
        struct command_ctx *cmd_ctx = NULL;
        struct lttng_poll_event events;
-       int client_sock = -1;
+       const int client_sock = thread_state.client_sock;
        struct lttng_pipe *quit_pipe = data;
        const int thread_quit_pipe_fd = lttng_pipe_get_readfd(quit_pipe);
 
@@ -2031,10 +2032,6 @@ static void *thread_manage_clients(void *data)
        is_root = (getuid() == 0);
 
        pthread_cleanup_push(thread_init_cleanup, NULL);
-       client_sock = create_client_sock();
-       if (client_sock < 0) {
-               goto error_listen;
-       }
 
        rcu_register_thread();
 
@@ -2273,11 +2270,9 @@ error:
 error_listen:
 error_create_poll:
        unlink(config.client_unix_sock_path.value);
-       if (client_sock >= 0) {
-               ret = close(client_sock);
-               if (ret) {
-                       PERROR("close");
-               }
+       ret = close(client_sock);
+       if (ret) {
+               PERROR("close");
        }
 
        if (err) {
@@ -2306,7 +2301,8 @@ struct lttng_thread *launch_client_thread(void)
 {
        bool thread_running;
        struct lttng_pipe *client_quit_pipe;
-       struct lttng_thread *thread;
+       struct lttng_thread *thread = NULL;
+       int client_sock_fd = -1;
 
        sem_init(&thread_state.ready, 0, 0);
        client_quit_pipe = lttng_pipe_open(FD_CLOEXEC);
@@ -2314,6 +2310,12 @@ struct lttng_thread *launch_client_thread(void)
                goto error;
        }
 
+       client_sock_fd = create_client_sock();
+       if (client_sock_fd < 0) {
+               goto error;
+       }
+
+       thread_state.client_sock = client_sock_fd;
        thread = lttng_thread_create("Client management",
                        thread_manage_clients,
                        shutdown_client_thread,
@@ -2322,6 +2324,9 @@ struct lttng_thread *launch_client_thread(void)
        if (!thread) {
                goto error;
        }
+       /* The client thread now owns the client sock fd and the quit pipe. */
+       client_sock_fd = -1;
+       client_quit_pipe = NULL;
 
        /*
         * This thread is part of the threads that need to be fully
@@ -2329,11 +2334,16 @@ struct lttng_thread *launch_client_thread(void)
         */
        thread_running = wait_thread_status();
        if (!thread_running) {
-               lttng_thread_put(thread);
-               thread = NULL;
+               goto error;
        }
        return thread;
 error:
+       if (client_sock_fd >= 0) {
+               if (close(client_sock_fd)) {
+                       PERROR("Failed to close client socket");
+               }
+       }
+       lttng_thread_put(thread);
        cleanup_client_thread(client_quit_pipe);
        return NULL;
 }
index c685442ba036e55ec24c413375d5409e50f56daf..ff6c0962f33768390500e7e5da2cedee55311a5f 100644 (file)
@@ -140,6 +140,9 @@ bool lttng_thread_get(struct lttng_thread *thread)
 
 void lttng_thread_put(struct lttng_thread *thread)
 {
+       if (!thread) {
+               return;
+       }
        assert(thread->ref.refcount);
        urcu_ref_put(&thread->ref, lttng_thread_release);
 }
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