Add a timeout to UST application socket
[lttng-tools.git] / src / bin / lttng-sessiond / main.c
index 9818b39569d9ee77eb84078d15ed5f12ad2f08ad..90f11d648e537fee78cbb88506dc6e026f675909 100644 (file)
@@ -228,6 +228,11 @@ struct health_state health_thread_app_manage;
 struct health_state health_thread_app_reg;
 struct health_state health_thread_kernel;
 
+/*
+ * Socket timeout for receiving and sending in seconds.
+ */
+static int app_socket_timeout;
+
 static
 void setup_consumerd_path(void)
 {
@@ -857,13 +862,6 @@ static void *thread_manage_consumer(void *data)
         */
        health_poll_update(&consumer_data->health);
 
-       health_code_update(&consumer_data->health);
-
-       ret = lttcomm_listen_unix_sock(consumer_data->err_sock);
-       if (ret < 0) {
-               goto error_listen;
-       }
-
        /*
         * Pass 2 as size here for the thread quit pipe and kconsumerd_err_sock.
         * Nothing more will be added to this poll set.
@@ -873,6 +871,11 @@ static void *thread_manage_consumer(void *data)
                goto error_poll;
        }
 
+       /*
+        * The error socket here is already in a listening state which was done
+        * just before spawning this thread to avoid a race between the consumer
+        * daemon exec trying to connect and the listen() call.
+        */
        ret = lttng_poll_add(&events, consumer_data->err_sock, LPOLLIN | LPOLLRDHUP);
        if (ret < 0) {
                goto error;
@@ -928,6 +931,12 @@ restart:
                goto error;
        }
 
+       /*
+        * Set the CLOEXEC flag. Return code is useless because either way, the
+        * show must go on.
+        */
+       (void) utils_set_fd_cloexec(sock);
+
        health_code_update(&consumer_data->health);
 
        DBG2("Receiving code from consumer err_sock");
@@ -1062,7 +1071,6 @@ error:
 
        lttng_poll_clean(&events);
 error_poll:
-error_listen:
        if (err) {
                health_error(&consumer_data->health);
                ERR("Health error occurred in %s", __func__);
@@ -1192,16 +1200,22 @@ static void *thread_manage_apps(void *data)
                                                ust_app_unregister(ust_cmd.sock);
                                        } else {
                                                /*
-                                                * We just need here to monitor the close of the UST
-                                                * socket and poll set monitor those by default.
-                                                * Listen on POLLIN (even if we never expect any
-                                                * data) to ensure that hangup wakes us.
+                                                * We only monitor the error events of the socket. This
+                                                * thread does not handle any incoming data from UST
+                                                * (POLLIN).
                                                 */
-                                               ret = lttng_poll_add(&events, ust_cmd.sock, LPOLLIN);
+                                               ret = lttng_poll_add(&events, ust_cmd.sock,
+                                                               LPOLLERR & LPOLLHUP & LPOLLRDHUP);
                                                if (ret < 0) {
                                                        goto error;
                                                }
 
+                                               /* Set socket timeout for both receiving and ending */
+                                               (void) lttcomm_setsockopt_rcv_timeout(ust_cmd.sock,
+                                                               app_socket_timeout);
+                                               (void) lttcomm_setsockopt_snd_timeout(ust_cmd.sock,
+                                                               app_socket_timeout);
+
                                                DBG("Apps with sock %d added to poll set",
                                                                ust_cmd.sock);
                                        }
@@ -1402,6 +1416,12 @@ static void *thread_registration_apps(void *data)
                                                goto error;
                                        }
 
+                                       /*
+                                        * Set the CLOEXEC flag. Return code is useless because
+                                        * either way, the show must go on.
+                                        */
+                                       (void) utils_set_fd_cloexec(sock);
+
                                        /* Create UST registration command for enqueuing */
                                        ust_cmd = zmalloc(sizeof(struct ust_command));
                                        if (ust_cmd == NULL) {
@@ -1814,7 +1834,17 @@ error:
  */
 static int start_consumerd(struct consumer_data *consumer_data)
 {
-       int ret;
+       int ret, err;
+
+       /*
+        * Set the listen() state on the socket since there is a possible race
+        * between the exec() of the consumer daemon and this call if place in the
+        * consumer thread. See bug #366 for more details.
+        */
+       ret = lttcomm_listen_unix_sock(consumer_data->err_sock);
+       if (ret < 0) {
+               goto error;
+       }
 
        pthread_mutex_lock(&consumer_data->pid_mutex);
        if (consumer_data->pid != 0) {
@@ -1845,6 +1875,13 @@ end:
        return 0;
 
 error:
+       /* Cleanup already created socket on error. */
+       if (consumer_data->err_sock >= 0) {
+               err = close(consumer_data->err_sock);
+               if (err < 0) {
+                       PERROR("close consumer data error socket");
+               }
+       }
        return ret;
 }
 
@@ -2134,7 +2171,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_LIST_DOMAINS:
        case LTTNG_START_TRACE:
        case LTTNG_STOP_TRACE:
-       case LTTNG_DATA_AVAILABLE:
+       case LTTNG_DATA_PENDING:
                need_domain = 0;
                break;
        default:
@@ -2408,7 +2445,7 @@ skip_domain:
                ret = cmd_add_context(cmd_ctx->session, cmd_ctx->lsm->domain.type,
                                cmd_ctx->lsm->u.context.channel_name,
                                cmd_ctx->lsm->u.context.event_name,
-                               &cmd_ctx->lsm->u.context.ctx);
+                               &cmd_ctx->lsm->u.context.ctx, kernel_poll_pipe[1]);
                break;
        }
        case LTTNG_DISABLE_CHANNEL:
@@ -2829,9 +2866,9 @@ skip_domain:
                                bytecode);
                break;
        }
-       case LTTNG_DATA_AVAILABLE:
+       case LTTNG_DATA_PENDING:
        {
-               ret = cmd_data_available(cmd_ctx->session);
+               ret = cmd_data_pending(cmd_ctx->session);
                break;
        }
        default:
@@ -2882,6 +2919,12 @@ static void *thread_manage_health(void *data)
                goto error;
        }
 
+       /*
+        * Set the CLOEXEC flag. Return code is useless because either way, the
+        * show must go on.
+        */
+       (void) utils_set_fd_cloexec(sock);
+
        ret = lttcomm_listen_unix_sock(sock);
        if (ret < 0) {
                goto error;
@@ -2946,6 +2989,12 @@ restart:
                        goto error;
                }
 
+               /*
+                * Set the CLOEXEC flag. Return code is useless because either way, the
+                * show must go on.
+                */
+               (void) utils_set_fd_cloexec(new_sock);
+
                DBG("Receiving data from client for health...");
                ret = lttcomm_recv_unix_sock(new_sock, (void *)&msg, sizeof(msg));
                if (ret <= 0) {
@@ -3143,6 +3192,12 @@ static void *thread_manage_clients(void *data)
                        goto error;
                }
 
+               /*
+                * Set the CLOEXEC flag. Return code is useless because either way, the
+                * show must go on.
+                */
+               (void) utils_set_fd_cloexec(sock);
+
                /* Set socket option for credentials retrieval */
                ret = lttcomm_setsockopt_creds_unix_sock(sock);
                if (ret < 0) {
@@ -3443,6 +3498,14 @@ static int init_daemon_socket(void)
                goto end;
        }
 
+       /* Set the cloexec flag */
+       ret = utils_set_fd_cloexec(client_sock);
+       if (ret < 0) {
+               ERR("Unable to set CLOEXEC flag to the client Unix socket (fd: %d). "
+                               "Continuing but note that the consumer daemon will have a "
+                               "reference to this socket on exec()", client_sock);
+       }
+
        /* File permission MUST be 660 */
        ret = chmod(client_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
        if (ret < 0) {
@@ -3459,6 +3522,14 @@ static int init_daemon_socket(void)
                goto end;
        }
 
+       /* Set the cloexec flag */
+       ret = utils_set_fd_cloexec(apps_sock);
+       if (ret < 0) {
+               ERR("Unable to set CLOEXEC flag to the app Unix socket (fd: %d). "
+                               "Continuing but note that the consumer daemon will have a "
+                               "reference to this socket on exec()", apps_sock);
+       }
+
        /* File permission MUST be 666 */
        ret = chmod(apps_unix_sock_path,
                        S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
@@ -3468,6 +3539,9 @@ static int init_daemon_socket(void)
                goto end;
        }
 
+       DBG3("Session daemon client socket %d and application socket %d created",
+                       client_sock, apps_sock);
+
 end:
        umask(old_umask);
        return ret;
@@ -3727,7 +3801,7 @@ int main(int argc, char **argv)
 {
        int ret = 0;
        void *status;
-       const char *home_path;
+       const char *home_path, *env_app_timeout;
 
        init_kernel_workarounds();
 
@@ -4007,6 +4081,14 @@ int main(int argc, char **argv)
        health_init(&ustconsumer64_data.health);
        health_poll_update(&ustconsumer64_data.health);
 
+       /* Check for the application socket timeout env variable. */
+       env_app_timeout = getenv(DEFAULT_APP_SOCKET_TIMEOUT_ENV);
+       if (env_app_timeout) {
+               app_socket_timeout = atoi(env_app_timeout);
+       } else {
+               app_socket_timeout = DEFAULT_APP_SOCKET_RW_TIMEOUT;
+       }
+
        /* Create thread to manage the client socket */
        ret = pthread_create(&health_thread, NULL,
                        thread_manage_health, (void *) NULL);
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