#include "agent.h"
#include "ht-cleanup.h"
#include "sessiond-config.h"
+#include "clear.h"
static const char *help_msg =
#ifdef LTTNG_EMBED_HELP
struct lttng_ht *agent_apps_ht_by_sock = NULL;
/*
- * Whether sessiond is ready for commands/notification channel/health check
+ * The initialization of the session daemon is done in multiple phases.
+ *
+ * While all threads are launched near-simultaneously, only some of them
+ * are needed to ensure the session daemon can start to respond to client
* requests.
- * NR_LTTNG_SESSIOND_READY must match the number of calls to
- * sessiond_notify_ready().
+ *
+ * There are two important guarantees that we wish to offer with respect
+ * to the initialisation of the session daemon:
+ * - When the daemonize/background launcher process exits, the sessiond
+ * is fully able to respond to client requests,
+ * - Auto-loaded sessions are visible to clients.
+ *
+ * In order to achieve this, a number of support threads have to be launched
+ * to allow the "client" thread to function properly. Moreover, since the
+ * "load session" thread needs the client thread, we must provide a way
+ * for the "load session" thread to know that the "client" thread is up
+ * and running.
+ *
+ * Hence, the support threads decrement the lttng_sessiond_ready counter
+ * while the "client" threads waits for it to reach 0. Once the "client" thread
+ * unblocks, it posts the message_thread_ready semaphore which allows the
+ * "load session" thread to progress.
+ *
+ * This implies that the "load session" thread is the last to be initialized
+ * and will explicitly call sessiond_signal_parents(), which signals the parents
+ * that the session daemon is fully initialized.
+ *
+ * The three (3) support threads are:
+ * - agent_thread
+ * - notification_thread
+ * - health_thread
*/
-#define NR_LTTNG_SESSIOND_READY 4
-int lttng_sessiond_ready = NR_LTTNG_SESSIOND_READY;
+int lttng_sessiond_ready = 3;
int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
{
/* Notify parents that we are ready for cmd and health check */
LTTNG_HIDDEN
-void sessiond_notify_ready(void)
+void sessiond_signal_parents(void)
{
- if (uatomic_sub_return(<tng_sessiond_ready, 1) == 0) {
- /*
- * Notify parent pid that we are ready to accept command
- * for client side. This ppid is the one from the
- * external process that spawned us.
- */
- if (config.sig_parent) {
- kill(ppid, SIGUSR1);
- }
+ /*
+ * Notify parent pid that we are ready to accept command
+ * for client side. This ppid is the one from the
+ * external process that spawned us.
+ */
+ if (config.sig_parent) {
+ kill(ppid, SIGUSR1);
+ }
- /*
- * Notify the parent of the fork() process that we are
- * ready.
- */
- if (config.daemonize || config.background) {
- kill(child_ppid, SIGUSR1);
- }
+ /*
+ * Notify the parent of the fork() process that we are
+ * ready.
+ */
+ if (config.daemonize || config.background) {
+ kill(child_ppid, SIGUSR1);
}
}
+LTTNG_HIDDEN
+void sessiond_notify_ready(void)
+{
+ /*
+ * The _return variant is used since the implied memory barriers are
+ * required.
+ */
+ (void) uatomic_sub_return(<tng_sessiond_ready, 1);
+}
+
static
int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
int *a_pipe)
*/
utils_close_pipe(thread_quit_pipe);
- /*
- * If config.pid_file_path.value is undefined, the default file will be
- * wiped when removing the rundir.
- */
- if (config.pid_file_path.value) {
- ret = remove(config.pid_file_path.value);
- if (ret < 0) {
- PERROR("remove pidfile %s", config.pid_file_path.value);
- }
+ ret = remove(config.pid_file_path.value);
+ if (ret < 0) {
+ PERROR("remove pidfile %s", config.pid_file_path.value);
}
DBG("Removing sessiond and consumerd content of directory %s",
free(load_info);
}
- /*
- * Cleanup lock file by deleting it and finaly closing it which will
- * release the file system lock.
- */
- if (lockfile_fd >= 0) {
- ret = remove(config.lock_file_path.value);
- if (ret < 0) {
- PERROR("remove lock file");
- }
- ret = close(lockfile_fd);
- if (ret < 0) {
- PERROR("close lock file");
- }
- }
-
/*
* We do NOT rmdir rundir because there are other processes
* using it, for instance lttng-relayd, which can start in
if (!cmd_socket_wrapper) {
goto error;
}
+ cmd_socket_wrapper->lock = &consumer_data->lock;
ret = consumer_send_channel_monitor_pipe(cmd_socket_wrapper,
consumer_data->channel_monitor_pipe);
* fallback on the 32-bit one,
*/
DBG3("Looking for a kernel consumer at these locations:");
- DBG3(" 1) %s", config.consumerd64_bin_path.value);
+ DBG3(" 1) %s", config.consumerd64_bin_path.value ? : "NULL");
DBG3(" 2) %s/%s", INSTALL_BIN_PATH, DEFAULT_CONSUMERD_FILE);
- DBG3(" 3) %s", config.consumerd32_bin_path.value);
+ DBG3(" 3) %s", config.consumerd32_bin_path.value ? : "NULL");
if (stat(config.consumerd64_bin_path.value, &st) == 0) {
DBG3("Found location #1");
consumer_to_use = config.consumerd64_bin_path.value;
} else if (stat(INSTALL_BIN_PATH "/" DEFAULT_CONSUMERD_FILE, &st) == 0) {
DBG3("Found location #2");
consumer_to_use = INSTALL_BIN_PATH "/" DEFAULT_CONSUMERD_FILE;
- } else if (stat(config.consumerd32_bin_path.value, &st) == 0) {
+ } else if (config.consumerd32_bin_path.value &&
+ stat(config.consumerd32_bin_path.value, &st) == 0) {
DBG3("Found location #3");
consumer_to_use = config.consumerd32_bin_path.value;
} else {
{
char *tmpnew = NULL;
- if (config.consumerd64_lib_dir.value[0] != '\0') {
+ if (config.consumerd64_lib_dir.value) {
char *tmp;
size_t tmplen;
if (!tmp) {
tmp = "";
}
- tmplen = strlen("LD_LIBRARY_PATH=")
- + strlen(config.consumerd64_lib_dir.value) + 1 /* : */ + strlen(tmp);
+ tmplen = strlen(config.consumerd64_lib_dir.value) + 1 /* : */ + strlen(tmp);
tmpnew = zmalloc(tmplen + 1 /* \0 */);
if (!tmpnew) {
ret = -ENOMEM;
goto error;
}
- strcpy(tmpnew, "LD_LIBRARY_PATH=");
strcat(tmpnew, config.consumerd64_lib_dir.value);
if (tmp[0] != '\0') {
strcat(tmpnew, ":");
strcat(tmpnew, tmp);
}
- ret = putenv(tmpnew);
+ ret = setenv("LD_LIBRARY_PATH", tmpnew, 1);
if (ret) {
ret = -errno;
free(tmpnew);
"--consumerd-err-sock", consumer_data->err_unix_sock_path,
"--group", config.tracing_group_name.value,
NULL);
- if (config.consumerd64_lib_dir.value[0] != '\0') {
- free(tmpnew);
- }
+ free(tmpnew);
break;
}
case LTTNG_CONSUMER32_UST:
{
char *tmpnew = NULL;
- if (config.consumerd32_lib_dir.value[0] != '\0') {
+ if (config.consumerd32_lib_dir.value) {
char *tmp;
size_t tmplen;
if (!tmp) {
tmp = "";
}
- tmplen = strlen("LD_LIBRARY_PATH=")
- + strlen(config.consumerd32_lib_dir.value) + 1 /* : */ + strlen(tmp);
+ tmplen = strlen(config.consumerd32_lib_dir.value) + 1 /* : */ + strlen(tmp);
tmpnew = zmalloc(tmplen + 1 /* \0 */);
if (!tmpnew) {
ret = -ENOMEM;
goto error;
}
- strcpy(tmpnew, "LD_LIBRARY_PATH=");
strcat(tmpnew, config.consumerd32_lib_dir.value);
if (tmp[0] != '\0') {
strcat(tmpnew, ":");
strcat(tmpnew, tmp);
}
- ret = putenv(tmpnew);
+ ret = setenv("LD_LIBRARY_PATH", tmpnew, 1);
if (ret) {
ret = -errno;
free(tmpnew);
"--consumerd-err-sock", consumer_data->err_unix_sock_path,
"--group", config.tracing_group_name.value,
NULL);
- if (config.consumerd32_lib_dir.value[0] != '\0') {
- free(tmpnew);
- }
+ free(tmpnew);
break;
}
default:
- PERROR("unknown consumer type");
+ ERR("unknown consumer type");
exit(EXIT_FAILURE);
}
if (errno != 0) {
case LTTNG_REGENERATE_STATEDUMP:
case LTTNG_REGISTER_TRIGGER:
case LTTNG_UNREGISTER_TRIGGER:
+ case LTTNG_CLEAR_SESSION:
need_domain = 0;
break;
default:
notification_thread_handle);
break;
}
+ case LTTNG_CLEAR_SESSION:
+ {
+ ret = cmd_clear_session(cmd_ctx->session);
+ if (ret != LTTNG_OK) {
+ goto error;
+ }
+ break;
+ }
default:
ret = LTTNG_ERR_UND;
break;
goto error;
}
- sessiond_notify_ready();
ret = sem_post(&load_info->message_thread_ready);
if (ret) {
PERROR("sem_post message_thread_ready");
goto error;
}
+ /*
+ * Wait until all support threads are initialized before accepting
+ * commands.
+ */
+ while (uatomic_read(<tng_sessiond_ready) != 0) {
+ fd_set read_fds;
+ struct timeval timeout;
+
+ FD_ZERO(&read_fds);
+ FD_SET(thread_quit_pipe[0], &read_fds);
+ memset(&timeout, 0, sizeof(timeout));
+ timeout.tv_usec = 1000;
+
+ /*
+ * If a support thread failed to launch, it may signal that
+ * we must exit and the sessiond would never be marked as
+ * "ready".
+ *
+ * The timeout is set to 1ms, which serves as a way to
+ * pace down this check.
+ */
+ ret = select(thread_quit_pipe[0] + 1, &read_fds, NULL, NULL,
+ &timeout);
+ if (ret > 0 || (ret < 0 && errno != EINTR)) {
+ goto exit;
+ }
+ }
+ /*
+ * This barrier is paired with the one in sessiond_notify_ready() to
+ * ensure that loads accessing data initialized by the other threads,
+ * on which this thread was waiting, are not performed before this point.
+ *
+ * Note that this could be a 'read' memory barrier, but a full barrier
+ * is used in case the code changes. The performance implications of
+ * this choice are minimal since this is a slow path.
+ */
+ cmm_smp_mb();
+
/* This testpoint is after we signal readiness to the parent. */
if (testpoint(sessiond_thread_manage_clients)) {
goto error;
} else if (string_match(optname, "no-kernel")) {
config.no_kernel = true;
} else if (string_match(optname, "quiet") || opt == 'q') {
- lttng_opt_quiet = true;
+ config.quiet = true;
} else if (string_match(optname, "verbose") || opt == 'v') {
/* Verbose level can increase using multiple -v */
if (arg) {
ERR("Port overflow in --agent-tcp-port parameter: %s", arg);
return -1;
}
- config.agent_tcp_port = (uint32_t) v;
- DBG3("Agent TCP port set to non default: %u", config.agent_tcp_port);
+ config.agent_tcp_port.begin = config.agent_tcp_port.end = (int) v;
+ DBG3("Agent TCP port set to non default: %i", (int) v);
}
} else if (string_match(optname, "load") || opt == 'l') {
if (!arg || *arg == '\0') {
return ret;
}
+/*
+ * Create lockfile using the rundir and return its fd.
+ */
+static int create_lockfile(void)
+{
+ return utils_create_lock_file(config.lock_file_path.value);
+}
+
/*
* Check if the global socket is available, and if a daemon is answering at the
* other side. If yes, error is returned.
+ *
+ * Also attempts to create and hold the lock file.
*/
static int check_existing_daemon(void)
{
+ int ret = 0;
+
/* Is there anybody out there ? */
if (lttng_session_daemon_alive()) {
- return -EEXIST;
+ ret = -EEXIST;
+ goto end;
}
- return 0;
+ lockfile_fd = create_lockfile();
+ if (lockfile_fd < 0) {
+ ret = -EEXIST;
+ goto end;
+ }
+end:
+ return ret;
+}
+
+static void sessiond_cleanup_lock_file(void)
+{
+ int ret;
+
+ /*
+ * Cleanup lock file by deleting it and finaly closing it which will
+ * release the file system lock.
+ */
+ if (lockfile_fd >= 0) {
+ ret = remove(config.lock_file_path.value);
+ if (ret < 0) {
+ PERROR("remove lock file");
+ }
+ ret = close(lockfile_fd);
+ if (ret < 0) {
+ PERROR("close lock file");
+ }
+ }
}
/*
return utils_create_pid_file(getpid(), config.pid_file_path.value);
}
-/*
- * Create lockfile using the rundir and return its fd.
- */
-static int create_lockfile(void)
-{
- return utils_create_lock_file(config.lock_file_path.value);
-}
-
-/*
- * Write agent TCP port using the rundir.
- */
-static int write_agent_port(void)
-{
- return utils_create_pid_file(config.agent_tcp_port,
- config.agent_port_file_path.value);
-}
-
static int set_clock_plugin_env(void)
{
int ret = 0;
goto exit_set_signal_handler;
}
+ /*
+ * Init config from environment variables.
+ * Command line option override env configuration per-doc. Do env first.
+ */
+ sessiond_config_apply_env_config(&config);
+
/*
* Parse arguments and load the daemon configuration file.
*
goto exit_options;
}
- /* Init config from environment variables. */
- sessiond_config_apply_env_config(&config);
-
/*
* Resolve all paths received as arguments, configuration option, or
* through environment variable as absolute paths. This is necessary
sessiond_config_log(&config);
+ if (create_lttng_rundir()) {
+ retval = -1;
+ goto exit_options;
+ }
+
+ /* Abort launch if a session daemon is already running. */
+ if (check_existing_daemon()) {
+ ERR("A session daemon is already running.");
+ retval = -1;
+ goto exit_options;
+ }
+
/* Daemonize */
if (config.daemonize || config.background) {
int i;
/*
* We are in the child. Make sure all other file descriptors are
* closed, in case we are called with more opened file
- * descriptors than the standard ones.
+ * descriptors than the standard ones and the lock file.
*/
for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
+ if (i == lockfile_fd) {
+ continue;
+ }
(void) close(i);
}
}
/* Check if daemon is UID = 0 */
is_root = !getuid();
-
- if (create_lttng_rundir()) {
- retval = -1;
- goto exit_init_data;
- }
-
if (is_root) {
/* Create global run dir with root access */
}
}
- lockfile_fd = create_lockfile();
- if (lockfile_fd < 0) {
- retval = -1;
- goto exit_init_data;
- }
-
/* Set consumer initial state */
kernel_consumerd_state = CONSUMER_STOPPED;
ust_consumerd_state = CONSUMER_STOPPED;
goto exit_init_data;
}
- /*
- * See if daemon already exist.
- */
- if (check_existing_daemon()) {
- ERR("Already running daemon.\n");
- /*
- * We do not goto exit because we must not cleanup()
- * because a daemon is already running.
- */
- retval = -1;
- goto exit_init_data;
- }
-
/*
* Init UST app hash table. Alloc hash table before this point since
* cleanup() can get called after that point.
retval = -1;
goto exit_init_data;
}
- ret = write_agent_port();
- if (ret) {
- ERR("Error in write_agent_port");
- retval = -1;
- goto exit_init_data;
- }
/* Initialize communication library */
lttcomm_init();
exit_create_run_as_worker_cleanup:
exit_options:
+ sessiond_cleanup_lock_file();
sessiond_cleanup_options();
exit_set_signal_handler:
projects / lttng-tools.git / blobdiff