Refactor relayd main/set_options/cleanup

- 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>

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 428e61361cc3625df776f88f3af1979571738b6b..4963043edbe390d1f78d70a90656441e67f24bab 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -94,7 +94,7 @@ static uint64_t last_relay_viewer_session_id;
  * Cleanup the daemon
  */
 static
-void cleanup(void)
+void cleanup_relayd_live(void)
 {
        DBG("Cleaning up");
 
@@ -345,20 +345,22 @@ int notify_thread_pipe(int wpipe)
  * Stop all threads by closing the thread quit pipe.
  */
 static
-void stop_threads(void)
+int stop_threads(void)
 {
-       int ret;
+       int ret, retval = 0;
 
        /* Stopping all threads */
        DBG("Terminating all live threads");
        ret = notify_thread_pipe(thread_quit_pipe[1]);
        if (ret < 0) {
                ERR("write error on thread quit pipe");
+               retval = -1;
        }
 
        /* Dispatch thread */
        CMM_STORE_SHARED(live_dispatch_thread_exit, 1);
        futex_nto1_wake(&viewer_conn_queue.futex);
+       return retval;
 }
 
 /*
@@ -595,7 +597,9 @@ error_sock_control:
        }
        health_unregister(health_relayd);
        DBG("Live viewer listener thread cleanup complete");
-       stop_threads();
+       if (stop_threads()) {
+               ERR("Error stopping live threads");
+       }
        return NULL;
 }
 
@@ -672,7 +676,9 @@ error_testpoint:
        }
        health_unregister(health_relayd);
        DBG("Live viewer dispatch thread dying");
-       stop_threads();
+       if (stop_threads()) {
+               ERR("Error stopping live threads");
+       }
        return NULL;
 }
 
@@ -2046,7 +2052,9 @@ error_testpoint:
                ERR("Health error occurred in %s", __func__);
        }
        health_unregister(health_relayd);
-       stop_threads();
+       if (stop_threads()) {
+               ERR("Error stopping live threads");
+       }
        rcu_unregister_thread();
        return NULL;
 }
@@ -2057,55 +2065,59 @@ error_testpoint:
  */
 static int create_conn_pipe(void)
 {
-       int ret;
-
-       ret = utils_create_pipe_cloexec(live_conn_pipe);
+       return utils_create_pipe_cloexec(live_conn_pipe);
+}
 
-       return ret;
+int relayd_live_stop(void)
+{
+       return stop_threads();
 }
 
-void live_stop_threads(void)
+int relayd_live_join(void)
 {
-       int ret;
+       int ret, retval = 0;
        void *status;
 
-       stop_threads();
-
        ret = pthread_join(live_listener_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live listener");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
 
        ret = pthread_join(live_worker_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live worker");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
 
        ret = pthread_join(live_dispatcher_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live dispatcher");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
 
-       cleanup();
+       cleanup_relayd_live();
 
-error:
-       return;
+       return retval;
 }
 
 /*
  * main
  */
-int live_start_threads(struct lttng_uri *uri,
+int relayd_live_create(struct lttng_uri *uri,
                struct relay_local_data *relay_ctx)
 {
-       int ret = 0;
+       int ret = 0, retval = 0;
        void *status;
        int is_root;
 
-       assert(uri);
+       if (!uri) {
+               retval = -1;
+               goto exit_init_data;
+       }
        live_uri = uri;
 
        /* Check if daemon is UID = 0 */
@@ -2114,14 +2126,15 @@ int live_start_threads(struct lttng_uri *uri,
        if (!is_root) {
                if (live_uri->port < 1024) {
                        ERR("Need to be root to use ports < 1024");
-                       ret = -1;
-                       goto exit;
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
        /* Setup the thread apps communication pipe. */
-       if ((ret = create_conn_pipe()) < 0) {
-               goto exit;
+       if (create_conn_pipe()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Init relay command queue. */
@@ -2133,55 +2146,65 @@ int live_start_threads(struct lttng_uri *uri,
        /* Setup the dispatcher thread */
        ret = pthread_create(&live_dispatcher_thread, NULL,
                        thread_dispatcher, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create viewer dispatcher");
-               goto exit_dispatcher;
+               retval = -1;
+               goto exit_dispatcher_thread;
        }
 
        /* Setup the worker thread */
        ret = pthread_create(&live_worker_thread, NULL,
                        thread_worker, relay_ctx);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create viewer worker");
-               goto exit_worker;
+               retval = -1;
+               goto exit_worker_thread;
        }
 
        /* Setup the listener thread */
        ret = pthread_create(&live_listener_thread, NULL,
                        thread_listener, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create viewer listener");
-               goto exit_listener;
+               retval = -1;
+               goto exit_listener_thread;
        }
 
-       ret = 0;
-       goto end;
+       /*
+        * All OK, started all threads.
+        */
+       return retval;
+
 
-exit_listener:
        ret = pthread_join(live_listener_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live listener");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
+exit_listener_thread:
 
-exit_worker:
        ret = pthread_join(live_worker_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live worker");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
+exit_worker_thread:
 
-exit_dispatcher:
        ret = pthread_join(live_dispatcher_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join live dispatcher");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
+exit_dispatcher_thread:
 
-exit:
-       cleanup();
+exit_init_data:
+       cleanup_relayd_live();
 
-end:
-error:
-       return ret;
+       return retval;
 }

diff --git a/src/bin/lttng-relayd/live.h b/src/bin/lttng-relayd/live.h
index 52608a4f7aeddabb87e2303cd2e730c68b33b8d1..5db940b3b915c0528e14d1dc02c7885496fc30ab 100644 (file)
--- a/src/bin/lttng-relayd/live.h
+++ b/src/bin/lttng-relayd/live.h
@@ -23,9 +23,10 @@
 
 #include "lttng-relayd.h"
 
-int live_start_threads(struct lttng_uri *live_uri,
+int relayd_live_create(struct lttng_uri *live_uri,
                struct relay_local_data *relay_ctx);
-void live_stop_threads(void);
+int relayd_live_stop(void);
+int relayd_live_join(void);
 
 struct relay_viewer_stream *live_find_viewer_stream_by_id(uint64_t stream_id);
 

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index e69ddd7d2cf9f7595a4e81d5324243c781aa58be..5147ef786ebc3a1e816ef828e9e95332c9a5a2fd 100644 (file)
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -335,7 +335,7 @@ end:
 static
 int set_options(int argc, char **argv)
 {
-       int c, ret = 0, option_index = 0;
+       int c, ret = 0, option_index = 0, retval = 0;
        int orig_optopt = optopt, orig_optind = optind;
        char *default_address, *optstring;
        const char *config_path = NULL;
@@ -343,7 +343,7 @@ int set_options(int argc, char **argv)
        optstring = utils_generate_optstring(long_options,
                        sizeof(long_options) / sizeof(struct option));
        if (!optstring) {
-               ret = -ENOMEM;
+               retval = -ENOMEM;
                goto exit;
        }
 
@@ -352,7 +352,7 @@ int set_options(int argc, char **argv)
        while ((c = getopt_long(argc, argv, optstring, long_options,
                                        &option_index)) != -1) {
                if (c == '?') {
-                       ret = -EINVAL;
+                       retval = -EINVAL;
                        goto exit;
                } else if (c != 'f') {
                        continue;
@@ -369,8 +369,8 @@ int set_options(int argc, char **argv)
        if (ret) {
                if (ret > 0) {
                        ERR("Invalid configuration option at line %i", ret);
-                       ret = -1;
                }
+               retval = -1;
                goto exit;
        }
 
@@ -385,6 +385,7 @@ int set_options(int argc, char **argv)
 
                ret = set_option(c, optarg, long_options[option_index].name);
                if (ret < 0) {
+                       retval = -1;
                        goto exit;
                }
        }
@@ -396,6 +397,7 @@ int set_options(int argc, char **argv)
                        DEFAULT_NETWORK_CONTROL_PORT);
                if (ret < 0) {
                        PERROR("asprintf default data address");
+                       retval = -1;
                        goto exit;
                }
 
@@ -403,6 +405,7 @@ int set_options(int argc, char **argv)
                free(default_address);
                if (ret < 0) {
                        ERR("Invalid control URI specified");
+                       retval = -1;
                        goto exit;
                }
        }
@@ -412,6 +415,7 @@ int set_options(int argc, char **argv)
                        DEFAULT_NETWORK_DATA_PORT);
                if (ret < 0) {
                        PERROR("asprintf default data address");
+                       retval = -1;
                        goto exit;
                }
 
@@ -419,6 +423,7 @@ int set_options(int argc, char **argv)
                free(default_address);
                if (ret < 0) {
                        ERR("Invalid data URI specified");
+                       retval = -1;
                        goto exit;
                }
        }
@@ -428,6 +433,7 @@ int set_options(int argc, char **argv)
                        DEFAULT_NETWORK_VIEWER_PORT);
                if (ret < 0) {
                        PERROR("asprintf default viewer control address");
+                       retval = -1;
                        goto exit;
                }
 
@@ -435,23 +441,32 @@ int set_options(int argc, char **argv)
                free(default_address);
                if (ret < 0) {
                        ERR("Invalid viewer control URI specified");
+                       retval = -1;
                        goto exit;
                }
        }
 
 exit:
        free(optstring);
-       return ret;
+       return retval;
 }
 
 /*
  * Cleanup the daemon
  */
 static
-void cleanup(void)
+void relayd_cleanup(struct relay_local_data *relay_ctx)
 {
        DBG("Cleaning up");
 
+       if (viewer_streams_ht)
+               lttng_ht_destroy(viewer_streams_ht);
+       if (relay_streams_ht)
+               lttng_ht_destroy(relay_streams_ht);
+       if (relay_ctx && relay_ctx->sessions_ht)
+               lttng_ht_destroy(relay_ctx->sessions_ht);
+       free(relay_ctx);
+
        /* free the dynamically allocated opt_output_path */
        free(opt_output_path);
 
@@ -513,6 +528,11 @@ void stop_threads(void)
        /* Dispatch thread */
        CMM_STORE_SHARED(dispatch_thread_exit, 1);
        futex_nto1_wake(&relay_conn_queue.futex);
+
+       ret = relayd_live_stop();
+       if (ret) {
+               ERR("Error stopping live threads");
+       }
 }
 
 /*
@@ -2724,32 +2744,36 @@ static int create_relay_conn_pipe(void)
  */
 int main(int argc, char **argv)
 {
-       int ret = 0;
+       int ret = 0, retval = 0;
        void *status;
-       struct relay_local_data *relay_ctx;
+       struct relay_local_data *relay_ctx = NULL;
 
        /* Parse arguments */
        progname = argv[0];
-       if ((ret = set_options(argc, argv)) < 0) {
-               goto exit;
+       if (set_options(argc, argv)) {
+               retval = -1;
+               goto exit_options;
        }
 
-       if ((ret = set_signal_handler()) < 0) {
-               goto exit;
+       if (set_signal_handler()) {
+               retval = -1;
+               goto exit_options;
        }
 
        /* Try to create directory if -o, --output is specified. */
        if (opt_output_path) {
                if (*opt_output_path != '/') {
                        ERR("Please specify an absolute path for -o, --output PATH");
-                       goto exit;
+                       retval = -1;
+                       goto exit_options;
                }
 
                ret = utils_mkdir_recursive(opt_output_path, S_IRWXU | S_IRWXG,
                                -1, -1);
                if (ret < 0) {
                        ERR("Unable to create %s", opt_output_path);
-                       goto exit;
+                       retval = -1;
+                       goto exit_options;
                }
        }
 
@@ -2760,7 +2784,8 @@ int main(int argc, char **argv)
                ret = lttng_daemonize(&child_ppid, &recv_child_signal,
                        !opt_background);
                if (ret < 0) {
-                       goto exit;
+                       retval = -1;
+                       goto exit_options;
                }
 
                /*
@@ -2773,9 +2798,19 @@ int main(int argc, char **argv)
                }
        }
 
+
+       /* Initialize thread health monitoring */
+       health_relayd = health_app_create(NR_HEALTH_RELAYD_TYPES);
+       if (!health_relayd) {
+               PERROR("health_app_create error");
+               retval = -1;
+               goto exit_health_app_create;
+       }
+
        /* Create thread quit pipe */
-       if ((ret = init_thread_quit_pipe()) < 0) {
-               goto error;
+       if (init_thread_quit_pipe()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* We need those values for the file/dir creation. */
@@ -2786,14 +2821,15 @@ int main(int argc, char **argv)
        if (relayd_uid == 0) {
                if (control_uri->port < 1024 || data_uri->port < 1024 || live_uri->port < 1024) {
                        ERR("Need to be root to use ports < 1024");
-                       ret = -1;
-                       goto exit;
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
        /* Setup the thread apps communication pipe. */
-       if ((ret = create_relay_conn_pipe()) < 0) {
-               goto exit;
+       if (create_relay_conn_pipe()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Init relay command queue. */
@@ -2809,134 +2845,139 @@ int main(int argc, char **argv)
        relay_ctx = zmalloc(sizeof(struct relay_local_data));
        if (!relay_ctx) {
                PERROR("relay_ctx");
-               goto exit;
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* tables of sessions indexed by session ID */
        relay_ctx->sessions_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!relay_ctx->sessions_ht) {
-               goto exit_relay_ctx_sessions;
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* tables of streams indexed by stream ID */
        relay_streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!relay_streams_ht) {
-               goto exit_relay_ctx_streams;
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* tables of streams indexed by stream ID */
        viewer_streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
        if (!viewer_streams_ht) {
-               goto exit_relay_ctx_viewer_streams;
-       }
-
-       /* Initialize thread health monitoring */
-       health_relayd = health_app_create(NR_HEALTH_RELAYD_TYPES);
-       if (!health_relayd) {
-               PERROR("health_app_create error");
-               goto exit_health_app_create;
+               retval = -1;
+               goto exit_init_data;
        }
 
        ret = utils_create_pipe(health_quit_pipe);
-       if (ret < 0) {
-               goto error_health_pipe;
+       if (ret) {
+               retval = -1;
+               goto exit_health_quit_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;
        }
 
        /* Setup the dispatcher thread */
        ret = pthread_create(&dispatcher_thread, NULL,
                        relay_thread_dispatcher, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create dispatcher");
-               goto exit_dispatcher;
+               retval = -1;
+               goto exit_dispatcher_thread;
        }
 
        /* Setup the worker thread */
        ret = pthread_create(&worker_thread, NULL,
                        relay_thread_worker, (void *) relay_ctx);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create worker");
-               goto exit_worker;
+               retval = -1;
+               goto exit_worker_thread;
        }
 
        /* Setup the listener thread */
        ret = pthread_create(&listener_thread, NULL,
                        relay_thread_listener, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create listener");
-               goto exit_listener;
+               retval = -1;
+               goto exit_listener_thread;
        }
 
-       ret = live_start_threads(live_uri, relay_ctx);
-       if (ret != 0) {
+       ret = relayd_live_create(live_uri, relay_ctx);
+       if (ret) {
                ERR("Starting live viewer threads");
+               retval = -1;
                goto exit_live;
        }
 
+       /*
+        * This is where we start awaiting program completion (e.g. through
+        * signal that asks threads to teardown).
+        */
+
+       ret = relayd_live_join();
+       if (ret) {
+               retval = -1;
+       }
 exit_live:
+
        ret = pthread_join(listener_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join listener_thread");
+               retval = -1;
        }
 
-exit_listener:
+exit_listener_thread:
        ret = pthread_join(worker_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join worker_thread");
+               retval = -1;
        }
 
-exit_worker:
+exit_worker_thread:
        ret = pthread_join(dispatcher_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join dispatcher_thread");
+               retval = -1;
        }
+exit_dispatcher_thread:
 
-exit_dispatcher:
        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:
 
-       /*
-        * Stop live threads only after joining other threads.
-        */
-       live_stop_threads();
-
-health_error:
        utils_close_pipe(health_quit_pipe);
+exit_health_quit_pipe:
 
-error_health_pipe:
+exit_init_data:
        health_app_destroy(health_relayd);
-
 exit_health_app_create:
-       lttng_ht_destroy(viewer_streams_ht);
-
-exit_relay_ctx_viewer_streams:
-       lttng_ht_destroy(relay_streams_ht);
-
-exit_relay_ctx_streams:
-       lttng_ht_destroy(relay_ctx->sessions_ht);
+exit_options:
+       relayd_cleanup(relay_ctx);
 
-exit_relay_ctx_sessions:
-       free(relay_ctx);
-
-exit:
-       cleanup();
-       if (!ret) {
+       if (!retval) {
                exit(EXIT_SUCCESS);
+       } else {
+               exit(EXIT_FAILURE);
        }
-
-error:
-       exit(EXIT_FAILURE);
 }