ltt-sessiond teardown cleanup
[lttng-tools.git] / ltt-sessiond / main.c
index cb8b98c7b7141ec4b9492738ee3d87abf846d4b5..98bdb6a4d6912c8a97117a59c114a6d54ee065ae 100644 (file)
@@ -99,6 +99,8 @@ static sem_t kconsumerd_sem;
 
 static pthread_mutex_t kconsumerd_pid_mutex;   /* Mutex to control kconsumerd pid assignation */
 
+static int modprobe_remove_kernel_modules(void);
+
 /*
  * Pointer initialized before thread creation.
  *
@@ -144,10 +146,18 @@ static void teardown_kernel_session(struct ltt_session *session)
        }
 }
 
+static void stop_threads(void)
+{
+       /* Stopping all threads */
+       DBG("Terminating all threads");
+       close(thread_quit_pipe[0]);
+       close(thread_quit_pipe[1]);
+}
+
 /*
  * Cleanup the daemon
  */
-static void cleanup()
+static void cleanup(void)
 {
        int ret;
        char *cmd;
@@ -161,11 +171,6 @@ static void cleanup()
                27, 1, 31, 27, 0, 27, 1, 33, 27, 0);
        /* </fun> */
 
-       /* Stopping all threads */
-       DBG("Terminating all threads");
-       close(thread_quit_pipe[0]);
-       close(thread_quit_pipe[1]);
-
        DBG("Removing %s directory", LTTNG_RUNDIR);
        ret = asprintf(&cmd, "rm -rf " LTTNG_RUNDIR);
        if (ret < 0) {
@@ -195,6 +200,9 @@ static void cleanup()
 
        DBG("Closing kernel fd");
        close(kernel_tracer_fd);
+
+       DBG("Unloading kernel modules");
+       modprobe_remove_kernel_modules();
 }
 
 /*
@@ -857,6 +865,23 @@ error:
        return ret;
 }
 
+static int join_kconsumerd_thread(void)
+{
+       void *status;
+       int ret;
+
+       if (kconsumerd_pid != 0) {
+               ret = kill(kconsumerd_pid, SIGTERM);
+               if (ret) {
+                       ERR("Error killing kconsumerd");
+                       return ret;
+               }
+               return pthread_join(kconsumerd_thread, &status);
+       } else {
+               return 0;
+       }
+}
+
 /*
  * Fork and exec a kernel consumer daemon (kconsumerd).
  *
@@ -944,22 +969,67 @@ error:
  */
 static int modprobe_kernel_modules(void)
 {
-       int ret = 0, i = 0;
+       int ret = 0, i;
        char modprobe[256];
 
-       while (kernel_modules_list[i] != NULL) {
-               ret = snprintf(modprobe, sizeof(modprobe), "/sbin/modprobe %s",
-                               kernel_modules_list[i]);
+       for (i = 0; i < ARRAY_SIZE(kernel_modules_list); i++) {
+               ret = snprintf(modprobe, sizeof(modprobe),
+                       "/sbin/modprobe %s%s",
+                       kernel_modules_list[i].required ? "" : "--quiet ",
+                       kernel_modules_list[i].name);
                if (ret < 0) {
                        perror("snprintf modprobe");
                        goto error;
                }
+               modprobe[sizeof(modprobe) - 1] = '\0';
                ret = system(modprobe);
+               if (ret == -1) {
+                       ERR("Unable to launch modprobe for module %s",
+                               kernel_modules_list[i].name);
+               } else if (kernel_modules_list[i].required
+                          && WEXITSTATUS(ret) != 0) {
+                       ERR("Unable to load module %s",
+                               kernel_modules_list[i].name);
+               } else {
+                       DBG("Modprobe successfully %s",
+                               kernel_modules_list[i].name);
+               }
+       }
+
+error:
+       return ret;
+}
+
+/*
+ * modprobe_remove_kernel_modules
+ * Remove modules in reverse load order.
+ */
+static int modprobe_remove_kernel_modules(void)
+{
+       int ret = 0, i;
+       char modprobe[256];
+
+       for (i = ARRAY_SIZE(kernel_modules_list) - 1; i >= 0; i--) {
+               ret = snprintf(modprobe, sizeof(modprobe),
+                       "/sbin/modprobe --remove --quiet %s",
+                       kernel_modules_list[i].name);
                if (ret < 0) {
-                       ERR("Unable to load module %s", kernel_modules_list[i]);
+                       perror("snprintf modprobe --remove");
+                       goto error;
+               }
+               modprobe[sizeof(modprobe) - 1] = '\0';
+               ret = system(modprobe);
+               if (ret == -1) {
+                       ERR("Unable to launch modprobe --remove for module %s",
+                               kernel_modules_list[i].name);
+               } else if (kernel_modules_list[i].required
+                          && WEXITSTATUS(ret) != 0) {
+                       ERR("Unable to remove module %s",
+                               kernel_modules_list[i].name);
+               } else {
+                       DBG("Modprobe removal successful %s",
+                               kernel_modules_list[i].name);
                }
-               DBG("Modprobe successfully %s", kernel_modules_list[i]);
-               i++;
        }
 
 error:
@@ -1271,6 +1341,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
        case LTTNG_CREATE_SESSION:
        case LTTNG_LIST_SESSIONS:
        case LTTNG_LIST_TRACEPOINTS:
+       case LTTNG_CALIBRATE:
                break;
        default:
                DBG("Getting session %s by name", cmd_ctx->lsm->session.name);
@@ -1291,7 +1362,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
        }
 
        /*
-        * Check domain type for specifif "pre-action".
+        * Check domain type for specific "pre-action".
         */
        switch (cmd_ctx->lsm->domain.type) {
        case LTTNG_DOMAIN_KERNEL:
@@ -1305,21 +1376,27 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
                }
 
                /* Need a session for kernel command */
-               if (cmd_ctx->lsm->cmd_type != LTTNG_LIST_TRACEPOINTS &&
-                               cmd_ctx->session->kernel_session == NULL) {
-
-                       ret = create_kernel_session(cmd_ctx->session);
-                       if (ret < 0) {
-                               ret = LTTCOMM_KERN_SESS_FAIL;
-                               goto error;
-                       }
-
-                       /* Start the kernel consumer daemon */
-                       if (kconsumerd_pid == 0) {
-                               ret = start_kconsumerd();
+               switch (cmd_ctx->lsm->cmd_type) {
+               case LTTNG_CREATE_SESSION:
+               case LTTNG_LIST_SESSIONS:
+               case LTTNG_LIST_TRACEPOINTS:
+               case LTTNG_CALIBRATE:
+                       break;
+               default:
+                       if (cmd_ctx->session->kernel_session == NULL) {
+                               ret = create_kernel_session(cmd_ctx->session);
                                if (ret < 0) {
+                                       ret = LTTCOMM_KERN_SESS_FAIL;
                                        goto error;
                                }
+
+                               /* Start the kernel consumer daemon */
+                               if (kconsumerd_pid == 0) {
+                                       ret = start_kconsumerd();
+                                       if (ret < 0) {
+                                               goto error;
+                                       }
+                               }
                        }
                }
                break;
@@ -1999,6 +2076,37 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
                ret = LTTCOMM_OK;
                break;
        }
+
+       case LTTNG_CALIBRATE:
+       {
+               /* Setup lttng message with no payload */
+               ret = setup_lttng_msg(cmd_ctx, 0);
+               if (ret < 0) {
+                       goto setup_error;
+               }
+
+               switch (cmd_ctx->lsm->domain.type) {
+               case LTTNG_DOMAIN_KERNEL:
+               {
+                       struct lttng_kernel_calibrate kcalibrate;
+
+                       kcalibrate.type = cmd_ctx->lsm->u.calibrate.type;
+                       ret = kernel_calibrate(kernel_tracer_fd, &kcalibrate);
+                       if (ret < 0) {
+                               ret = LTTCOMM_KERN_ENABLE_FAIL;
+                               goto error;
+                       }
+                       break;
+               }
+               default:
+                       /* TODO: Userspace tracing */
+                       ret = LTTCOMM_NOT_IMPLEMENTED;
+                       goto error;
+               }
+               ret = LTTCOMM_OK;
+               break;
+       }
+
        default:
                /* Undefined command */
                ret = setup_lttng_msg(cmd_ctx, 0);
@@ -2259,7 +2367,7 @@ static int parse_args(int argc, char **argv)
  *         apps_sock - The communication socket for all UST apps.
  *         client_sock - The communication of the cli tool (lttng).
  */
-static int init_daemon_socket()
+static int init_daemon_socket(void)
 {
        int ret = 0;
        mode_t old_umask;
@@ -2306,7 +2414,7 @@ end:
 /*
  * Check if the global socket is available.  If yes, error is returned.
  */
-static int check_existing_daemon()
+static int check_existing_daemon(void)
 {
        int ret;
 
@@ -2448,26 +2556,27 @@ error:
 
 /*
  * Signal handler for the daemon
+ *
+ * Simply stop all worker threads, leaving main() return gracefully
+ * after joining all threads and calling cleanup().
  */
 static void sighandler(int sig)
 {
        switch (sig) {
-               case SIGPIPE:
-                       DBG("SIGPIPE catched");
-                       return;
-               case SIGINT:
-                       DBG("SIGINT catched");
-                       cleanup();
-                       break;
-               case SIGTERM:
-                       DBG("SIGTERM catched");
-                       cleanup();
-                       break;
-               default:
-                       break;
+       case SIGPIPE:
+               DBG("SIGPIPE catched");
+               return;
+       case SIGINT:
+               DBG("SIGINT catched");
+               stop_threads();
+               break;
+       case SIGTERM:
+               DBG("SIGTERM catched");
+               stop_threads();
+               break;
+       default:
+               break;
        }
-
-       exit(EXIT_SUCCESS);
 }
 
 /*
@@ -2537,14 +2646,14 @@ int main(int argc, char **argv)
        const char *home_path;
 
        /* Create thread quit pipe */
-       if (init_thread_quit_pipe() < 0) {
-               goto exit;
+       if ((ret = init_thread_quit_pipe()) < 0) {
+               goto error;
        }
 
        /* Parse arguments */
        progname = argv[0];
        if ((ret = parse_args(argc, argv) < 0)) {
-               goto exit;
+               goto error;
        }
 
        /* Daemonize */
@@ -2552,7 +2661,7 @@ int main(int argc, char **argv)
                ret = daemon(0, 0);
                if (ret < 0) {
                        perror("daemon");
-                       goto exit;
+                       goto error;
                }
        }
 
@@ -2562,7 +2671,7 @@ int main(int argc, char **argv)
        if (is_root) {
                ret = create_lttng_rundir();
                if (ret < 0) {
-                       goto exit;
+                       goto error;
                }
 
                if (strlen(apps_unix_sock_path) == 0) {
@@ -2579,7 +2688,8 @@ int main(int argc, char **argv)
                if (home_path == NULL) {
                        /* TODO: Add --socket PATH option */
                        ERR("Can't get HOME directory for sockets creation.");
-                       goto exit;
+                       ret = -EPERM;
+                       goto error;
                }
 
                if (strlen(apps_unix_sock_path) == 0) {
@@ -2605,10 +2715,10 @@ int main(int argc, char **argv)
        if ((ret = check_existing_daemon()) == 0) {
                ERR("Already running daemon.\n");
                /*
-                * We do not goto error because we must not cleanup() because a daemon
-                * is already running.
+                * We do not goto exit because we must not cleanup()
+                * because a daemon is already running.
                 */
-               goto exit;
+               goto error;
        }
 
        /* After this point, we can safely call cleanup() so goto error is used */
@@ -2622,7 +2732,7 @@ int main(int argc, char **argv)
        if (is_root) {
                ret = set_kconsumerd_sockets();
                if (ret < 0) {
-                       goto error;
+                       goto exit;
                }
 
                /* Setup kernel tracer */
@@ -2632,18 +2742,18 @@ int main(int argc, char **argv)
                set_ulimit();
        }
 
-       if (set_signal_handler() < 0) {
-               goto error;
+       if ((ret = set_signal_handler()) < 0) {
+               goto exit;
        }
 
        /* Setup the needed unix socket */
-       if (init_daemon_socket() < 0) {
-               goto error;
+       if ((ret = init_daemon_socket()) < 0) {
+               goto exit;
        }
 
        /* Set credentials to socket */
-       if (is_root && (set_permissions() < 0)) {
-               goto error;
+       if (is_root && ((ret = set_permissions()) < 0)) {
+               goto exit;
        }
 
        /* Get parent pid if -S, --sig-parent is specified. */
@@ -2652,8 +2762,8 @@ int main(int argc, char **argv)
        }
 
        /* Setup the kernel pipe for waking up the kernel thread */
-       if (create_kernel_poll_pipe() < 0) {
-               goto error;
+       if ((ret = create_kernel_poll_pipe()) < 0) {
+               goto exit;
        }
 
        /*
@@ -2662,41 +2772,61 @@ int main(int argc, char **argv)
         */
        session_list_ptr = get_session_list();
 
-       while (1) {
-               /* Create thread to manage the client socket */
-               ret = pthread_create(&client_thread, NULL, thread_manage_clients, (void *) NULL);
-               if (ret != 0) {
-                       perror("pthread_create");
-                       goto error;
-               }
+       /* Create thread to manage the client socket */
+       ret = pthread_create(&client_thread, NULL, thread_manage_clients, (void *) NULL);
+       if (ret != 0) {
+               perror("pthread_create");
+               goto exit_client;
+       }
 
-               /* Create thread to manage application socket */
-               ret = pthread_create(&apps_thread, NULL, thread_manage_apps, (void *) NULL);
-               if (ret != 0) {
-                       perror("pthread_create");
-                       goto error;
-               }
+       /* Create thread to manage application socket */
+       ret = pthread_create(&apps_thread, NULL, thread_manage_apps, (void *) NULL);
+       if (ret != 0) {
+               perror("pthread_create");
+               goto exit_apps;
+       }
 
-               /* Create kernel thread to manage kernel event */
-               ret = pthread_create(&kernel_thread, NULL, thread_manage_kernel, (void *) NULL);
-               if (ret != 0) {
-                       perror("pthread_create");
-                       goto error;
-               }
+       /* Create kernel thread to manage kernel event */
+       ret = pthread_create(&kernel_thread, NULL, thread_manage_kernel, (void *) NULL);
+       if (ret != 0) {
+               perror("pthread_create");
+               goto exit_kernel;
+       }
 
-               ret = pthread_join(client_thread, &status);
-               if (ret != 0) {
-                       perror("pthread_join");
-                       goto error;
-               }
+       ret = pthread_join(kernel_thread, &status);
+       if (ret != 0) {
+               perror("pthread_join");
+               goto error;     /* join error, exit without cleanup */
        }
 
-       cleanup();
-       exit(EXIT_SUCCESS);
+exit_kernel:
+       ret = pthread_join(apps_thread, &status);
+       if (ret != 0) {
+               perror("pthread_join");
+               goto error;     /* join error, exit without cleanup */
+       }
 
-error:
-       cleanup();
+exit_apps:
+       ret = pthread_join(client_thread, &status);
+       if (ret != 0) {
+               perror("pthread_join");
+               goto error;     /* join error, exit without cleanup */
+       }
+
+       ret = join_kconsumerd_thread();
+       if (ret != 0) {
+               perror("join_kconsumerd");
+               goto error;     /* join error, exit without cleanup */
+       }
 
+exit_client:
 exit:
+       /*
+        * cleanup() is called when no other thread is running.
+        */
+       cleanup();
+       if (!ret)
+               exit(EXIT_SUCCESS);
+error:
        exit(EXIT_FAILURE);
 }
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