Refactor consumerd main/cleanup
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Thu, 18 Dec 2014 01:45:23 +0000 (20:45 -0500)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Wed, 7 Jan 2015 20:53:53 +0000 (15:53 -0500)
- Enforce symmetry between allocation and teardown,
- Handle all errors,
- Return all errors as EXIT_FAILURE,
- Standardize on zero being success, nonzero being error,
  (rather than < 0 being error),
- Fix pthread PERROR: we need to store ret into errno before
  calling PERROR, since pthread API does not set errno,
- Join errors now fall-through, rather than rely on the OS
  to teardown the rest.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
src/bin/lttng-consumerd/lttng-consumerd.c

index d0d83988c7beceb6d3196d523260b55feb0a30a9..b43e8f1503869c857889f85ba177fd95357ec9b6 100644 (file)
@@ -294,12 +294,20 @@ static void set_ulimit(void)
  */
 int main(int argc, char **argv)
 {
-       int ret = 0;
+       int ret = 0, retval = 0;
        void *status;
 
+       if (set_signal_handler()) {
+               retval = -1;
+               goto exit_set_signal_handler;
+       }
+
        /* Parse arguments */
        progname = argv[0];
-       parse_args(argc, argv);
+       if (parse_args(argc, argv)) {
+               retval = -1;
+               goto exit_options;
+       }
 
        /* Daemonize */
        if (opt_daemon) {
@@ -313,7 +321,8 @@ int main(int argc, char **argv)
                ret = daemon(0, 0);
                if (ret < 0) {
                        PERROR("daemon");
-                       goto error;
+                       retval = -1;
+                       goto exit_options;
                }
                /*
                 * We are in the child. Make sure all other file
@@ -325,36 +334,65 @@ int main(int argc, char **argv)
                }
        }
 
+       /*
+        * Starting from here, we can create threads. This needs to be after
+        * lttng_daemonize due to RCU.
+        */
+
+       health_consumerd = health_app_create(NR_HEALTH_CONSUMERD_TYPES);
+       if (!health_consumerd) {
+               retval = -1;
+               goto exit_health_consumerd_cleanup;
+       }
+
        /* Set up max poll set size */
        lttng_poll_set_max_size();
 
        if (*command_sock_path == '\0') {
                switch (opt_type) {
                case LTTNG_CONSUMER_KERNEL:
-                       snprintf(command_sock_path, PATH_MAX, DEFAULT_KCONSUMERD_CMD_SOCK_PATH,
+                       ret = snprintf(command_sock_path, PATH_MAX,
+                                       DEFAULT_KCONSUMERD_CMD_SOCK_PATH,
                                        DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                case LTTNG_CONSUMER64_UST:
-                       snprintf(command_sock_path, PATH_MAX,
-                                       DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH, DEFAULT_LTTNG_RUNDIR);
+                       ret = snprintf(command_sock_path, PATH_MAX,
+                                       DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH,
+                                       DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                case LTTNG_CONSUMER32_UST:
-                       snprintf(command_sock_path, PATH_MAX,
-                                       DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH, DEFAULT_LTTNG_RUNDIR);
+                       ret = snprintf(command_sock_path, PATH_MAX,
+                                       DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH,
+                                       DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                default:
-                       WARN("Unknown consumerd type");
-                       goto error;
+                       ERR("Unknown consumerd type");
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
        /* Init */
-       if (lttng_consumer_init() < 0) {
-               goto error;
+       if (lttng_consumer_init()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
-       /* Init socket timeouts */
+       /* Initialize communication library */
        lttcomm_init();
+       /* Initialize TCP timeout values */
        lttcomm_inet_init();
 
        if (!getuid()) {
@@ -362,47 +400,58 @@ int main(int argc, char **argv)
                set_ulimit();
        }
 
-       health_consumerd = health_app_create(NR_HEALTH_CONSUMERD_TYPES);
-       if (!health_consumerd) {
-               goto error;
-       }
-
        /* create the consumer instance with and assign the callbacks */
        ctx = lttng_consumer_create(opt_type, lttng_consumer_read_subbuffer,
                NULL, lttng_consumer_on_recv_stream, NULL);
-       if (ctx == NULL) {
-               goto error;
+       if (!ctx) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        lttng_consumer_set_command_sock_path(ctx, command_sock_path);
        if (*error_sock_path == '\0') {
                switch (opt_type) {
                case LTTNG_CONSUMER_KERNEL:
-                       snprintf(error_sock_path, PATH_MAX, DEFAULT_KCONSUMERD_ERR_SOCK_PATH,
+                       ret = snprintf(error_sock_path, PATH_MAX,
+                                       DEFAULT_KCONSUMERD_ERR_SOCK_PATH,
                                        DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                case LTTNG_CONSUMER64_UST:
-                       snprintf(error_sock_path, PATH_MAX,
-                                       DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH, DEFAULT_LTTNG_RUNDIR);
+                       ret = snprintf(error_sock_path, PATH_MAX,
+                                       DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH,
+                                       DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                case LTTNG_CONSUMER32_UST:
-                       snprintf(error_sock_path, PATH_MAX,
-                                       DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH, DEFAULT_LTTNG_RUNDIR);
+                       ret = snprintf(error_sock_path, PATH_MAX,
+                                       DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH,
+                                       DEFAULT_LTTNG_RUNDIR);
+                       if (ret < 0) {
+                               retval = -1;
+                               goto exit_init_data;
+                       }
                        break;
                default:
-                       WARN("Unknown consumerd type");
-                       goto error;
+                       ERR("Unknown consumerd type");
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
-       if (set_signal_handler() < 0) {
-               goto error;
-       }
-
        /* Connect to the socket created by lttng-sessiond to report errors */
        DBG("Connecting to error socket %s", error_sock_path);
        ret = lttcomm_connect_unix_sock(error_sock_path);
-       /* not a fatal error, but all communication with lttng-sessiond will fail */
+       /*
+        * Not a fatal error, but all communication with lttng-sessiond will
+        * fail.
+        */
        if (ret < 0) {
                WARN("Cannot connect to error socket (is lttng-sessiond started?)");
        }
@@ -412,21 +461,26 @@ int main(int argc, char **argv)
         * Block RT signals used for UST periodical metadata flush and the live
         * timer in main, and create a dedicated thread to handle these signals.
         */
-       consumer_signal_init();
+       if (consumer_signal_init()) {
+               retval = -1;
+               goto exit_init_data;
+       }
 
        ctx->type = opt_type;
 
-       ret = utils_create_pipe(health_quit_pipe);
-       if (ret < 0) {
-               goto error_health_pipe;
+       if (utils_create_pipe(health_quit_pipe)) {
+               retval = -1;
+               goto exit_health_pipe;
        }
 
        /* Create thread to manage the client socket */
        ret = pthread_create(&health_thread, NULL,
                        thread_manage_health, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create health");
-               goto health_error;
+               retval = -1;
+               goto exit_health_thread;
        }
 
        /*
@@ -439,35 +493,46 @@ int main(int argc, char **argv)
        cmm_smp_mb();   /* Read ready before following operations */
 
        /* Create thread to manage channels */
-       ret = pthread_create(&channel_thread, NULL, consumer_thread_channel_poll,
+       ret = pthread_create(&channel_thread, NULL,
+                       consumer_thread_channel_poll,
                        (void *) ctx);
-       if (ret != 0) {
-               perror("pthread_create");
-               goto channel_error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create");
+               retval = -1;
+               goto exit_channel_thread;
        }
 
        /* Create thread to manage the polling/writing of trace metadata */
-       ret = pthread_create(&metadata_thread, NULL, consumer_thread_metadata_poll,
+       ret = pthread_create(&metadata_thread, NULL,
+                       consumer_thread_metadata_poll,
                        (void *) ctx);
-       if (ret != 0) {
-               perror("pthread_create");
-               goto metadata_error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create");
+               retval = -1;
+               goto exit_metadata_thread;
        }
 
        /* Create thread to manage the polling/writing of trace data */
        ret = pthread_create(&data_thread, NULL, consumer_thread_data_poll,
                        (void *) ctx);
-       if (ret != 0) {
-               perror("pthread_create");
-               goto data_error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create");
+               retval = -1;
+               goto exit_data_thread;
        }
 
        /* Create the thread to manage the receive of fd */
-       ret = pthread_create(&sessiond_thread, NULL, consumer_thread_sessiond_poll,
+       ret = pthread_create(&sessiond_thread, NULL,
+                       consumer_thread_sessiond_poll,
                        (void *) ctx);
-       if (ret != 0) {
-               perror("pthread_create");
-               goto sessiond_error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create");
+               retval = -1;
+               goto exit_sessiond_thread;
        }
 
        /*
@@ -476,70 +541,86 @@ int main(int argc, char **argv)
         */
        ret = pthread_create(&metadata_timer_thread, NULL,
                        consumer_timer_thread, (void *) ctx);
-       if (ret != 0) {
-               perror("pthread_create");
-               goto metadata_timer_error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create");
+               retval = -1;
+               goto exit_metadata_timer_thread;
        }
 
        ret = pthread_detach(metadata_timer_thread);
        if (ret) {
                errno = ret;
-               perror("pthread_detach");
+               PERROR("pthread_detach");
+               retval = -1;
+               goto exit_metadata_timer_detach;
        }
 
-metadata_timer_error:
+       /*
+        * This is where we start awaiting program completion (e.g. through
+        * signal that asks threads to teardown.
+        */
+
+exit_metadata_timer_detach:
+exit_metadata_timer_thread:
        ret = pthread_join(sessiond_thread, &status);
-       if (ret != 0) {
-               perror("pthread_join");
-               goto error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join sessiond_thread");
+               retval = -1;
        }
+exit_sessiond_thread:
 
-sessiond_error:
        ret = pthread_join(data_thread, &status);
-       if (ret != 0) {
-               perror("pthread_join");
-               goto error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join data_thread");
+               retval = -1;
        }
+exit_data_thread:
 
-data_error:
        ret = pthread_join(metadata_thread, &status);
-       if (ret != 0) {
-               perror("pthread_join");
-               goto error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join metadata_thread");
+               retval = -1;
        }
+exit_metadata_thread:
 
-metadata_error:
        ret = pthread_join(channel_thread, &status);
-       if (ret != 0) {
-               perror("pthread_join");
-               goto error;
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join channel_thread");
+               retval = -1;
        }
+exit_channel_thread:
 
-channel_error:
        ret = pthread_join(health_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join health thread");
-               goto error;     /* join error, exit without cleanup */
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join health_thread");
+               retval = -1;
        }
+exit_health_thread:
 
-health_error:
        utils_close_pipe(health_quit_pipe);
+exit_health_pipe:
 
-error_health_pipe:
-       if (!ret) {
-               ret = EXIT_SUCCESS;
-               goto end;
-       }
-
-error:
-       ret = EXIT_FAILURE;
-
-end:
+exit_init_data:
        lttng_consumer_destroy(ctx);
        lttng_consumer_cleanup();
+
        if (health_consumerd) {
                health_app_destroy(health_consumerd);
        }
+exit_health_consumerd_cleanup:
 
-       return ret;
+exit_options:
+
+exit_set_signal_handler:
+       if (!retval) {
+               exit(EXIT_SUCCESS);
+       } else {
+               exit(EXIT_FAILURE);
+       }
 }
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