[lttng-tools.git] / src / bin / lttng-sessiond / register.c

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *               2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stddef.h>
#include <stdlib.h>
#include <urcu.h>
#include <common/futex.h>
#include <common/macros.h>
#include <common/utils.h>
#include <sys/stat.h>

#include "register.h"
#include "lttng-sessiond.h"
#include "testpoint.h"
#include "health-sessiond.h"
#include "fd-limit.h"
#include "shm.h"
#include "utils.h"
#include "thread.h"

struct thread_notifiers {
	struct lttng_pipe *quit_pipe;
	struct ust_cmd_queue *ust_cmd_queue;
	sem_t ready;
	bool running;
};

/*
 * Creates the application socket.
 */
static int create_application_socket(void)
{
	int ret = 0;
	int apps_sock;
	const mode_t old_umask = umask(0);

	/* Create the application unix socket */
	apps_sock = lttcomm_create_unix_sock(config.apps_unix_sock_path.value);
	if (apps_sock < 0) {
		ERR("Create unix sock failed: %s", config.apps_unix_sock_path.value);
		ret = -1;
		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(config.apps_unix_sock_path.value,
			S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
	if (ret < 0) {
		PERROR("Set file permissions failed on %s",
				config.apps_unix_sock_path.value);
		goto end;
	}

	DBG3("Session daemon application socket created (fd = %d) ", apps_sock);
	ret = apps_sock;
end:
	umask(old_umask);
	return ret;
}

/*
 * Notify UST applications using the shm mmap futex.
 */
static int notify_ust_apps(int active, bool is_root)
{
	char *wait_shm_mmap;

	DBG("Notifying applications of session daemon state: %d", active);

	/* See shm.c for this call implying mmap, shm and futex calls */
	wait_shm_mmap = shm_ust_get_mmap(config.wait_shm_path.value, is_root);
	if (wait_shm_mmap == NULL) {
		goto error;
	}

	/* Wake waiting process */
	futex_wait_update((int32_t *) wait_shm_mmap, active);

	/* Apps notified successfully */
	return 0;

error:
	return -1;
}

static void cleanup_application_registration_thread(void *data)
{
	struct thread_notifiers *notifiers = data;

	lttng_pipe_destroy(notifiers->quit_pipe);
	free(notifiers);
}

static void set_thread_status(struct thread_notifiers *notifiers, bool running)
{
	DBG("Marking application registration thread's state as %s", running ? "running" : "error");
	notifiers->running = running;
	sem_post(&notifiers->ready);
}

static bool wait_thread_status(struct thread_notifiers *notifiers)
{
	DBG("Waiting for application registration thread to be ready");
	sem_wait(&notifiers->ready);
	if (notifiers->running) {
		DBG("Application registration thread is ready");
	} else {
		ERR("Initialization of application registration thread failed");
	}

	return notifiers->running;
}

static void thread_init_cleanup(void *data)
{
	struct thread_notifiers *notifiers = data;

	set_thread_status(notifiers, false);
}

/*
 * This thread manage application registration.
 */
static void *thread_application_registration(void *data)
{
	int sock = -1, i, ret, pollfd, err = -1;
	int apps_sock = -1;
	uint32_t revents, nb_fd;
	struct lttng_poll_event events;
	/*
	 * Gets allocated in this thread, enqueued to a global queue, dequeued
	 * and freed in the manage apps thread.
	 */
	struct ust_command *ust_cmd = NULL;
	const bool is_root = (getuid() == 0);
	struct thread_notifiers *notifiers = data;
	const int quit_pipe_read_fd = lttng_pipe_get_readfd(
			notifiers->quit_pipe);

	DBG("[thread] Manage application registration started");

	pthread_cleanup_push(thread_init_cleanup, NULL);
	health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG);

	apps_sock = create_application_socket();
	if (apps_sock < 0) {
		goto error_listen;
	}

	ret = lttcomm_listen_unix_sock(apps_sock);
	if (ret < 0) {
		goto error_listen;
	}

	set_thread_status(notifiers, true);
	pthread_cleanup_pop(0);

	if (testpoint(sessiond_thread_registration_apps)) {
		goto error_create_poll;
	}

	/*
	 * Pass 2 as size here for the thread quit pipe and apps_sock. Nothing
	 * more will be added to this poll set.
	 */
	ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
	if (ret < 0) {
		goto error_create_poll;
	}

	/* Add the application registration socket */
	ret = lttng_poll_add(&events, apps_sock, LPOLLIN | LPOLLRDHUP);
	if (ret < 0) {
		goto error_poll_add;
	}

	/* Add the application registration socket */
	ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN | LPOLLRDHUP);
	if (ret < 0) {
		goto error_poll_add;
	}

	/* Notify all applications to register */
	ret = notify_ust_apps(1, is_root);
	if (ret < 0) {
		ERR("Failed to notify applications or create the wait shared memory.\n"
			"Execution continues but there might be problem for already\n"
			"running applications that wishes to register.");
	}

	while (1) {
		DBG("Accepting application registration");

		/* Inifinite blocking call, waiting for transmission */
	restart:
		health_poll_entry();
		ret = lttng_poll_wait(&events, -1);
		health_poll_exit();
		if (ret < 0) {
			/*
			 * Restart interrupted system call.
			 */
			if (errno == EINTR) {
				goto restart;
			}
			goto error;
		}

		nb_fd = ret;

		for (i = 0; i < nb_fd; i++) {
			health_code_update();

			/* Fetch once the poll data */
			revents = LTTNG_POLL_GETEV(&events, i);
			pollfd = LTTNG_POLL_GETFD(&events, i);

			/* Thread quit pipe has been closed. Killing thread. */
			if (pollfd == quit_pipe_read_fd) {
				err = 0;
				goto exit;
			} else {
				/* Event on the registration socket */
				if (revents & LPOLLIN) {
					sock = lttcomm_accept_unix_sock(apps_sock);
					if (sock < 0) {
						goto error;
					}

					/*
					 * Set socket timeout for both receiving and ending.
					 * app_socket_timeout is in seconds, whereas
					 * lttcomm_setsockopt_rcv_timeout and
					 * lttcomm_setsockopt_snd_timeout expect msec as
					 * parameter.
					 */
					if (config.app_socket_timeout >= 0) {
						(void) lttcomm_setsockopt_rcv_timeout(sock,
								config.app_socket_timeout * 1000);
						(void) lttcomm_setsockopt_snd_timeout(sock,
								config.app_socket_timeout * 1000);
					}

					/*
					 * 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) {
						PERROR("ust command zmalloc");
						ret = close(sock);
						if (ret) {
							PERROR("close");
						}
						goto error;
					}

					/*
					 * Using message-based transmissions to ensure we don't
					 * have to deal with partially received messages.
					 */
					ret = lttng_fd_get(LTTNG_FD_APPS, 1);
					if (ret < 0) {
						ERR("Exhausted file descriptors allowed for applications.");
						free(ust_cmd);
						ret = close(sock);
						if (ret) {
							PERROR("close");
						}
						sock = -1;
						continue;
					}

					health_code_update();
					ret = ust_app_recv_registration(sock, &ust_cmd->reg_msg);
					if (ret < 0) {
						free(ust_cmd);
						/* Close socket of the application. */
						ret = close(sock);
						if (ret) {
							PERROR("close");
						}
						lttng_fd_put(LTTNG_FD_APPS, 1);
						sock = -1;
						continue;
					}
					health_code_update();

					ust_cmd->sock = sock;
					sock = -1;

					DBG("UST registration received with pid:%d ppid:%d uid:%d"
							" gid:%d sock:%d name:%s (version %d.%d)",
							ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid,
							ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid,
							ust_cmd->sock, ust_cmd->reg_msg.name,
							ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor);

					/*
					 * Lock free enqueue the registration request. The red pill
					 * has been taken! This apps will be part of the *system*.
					 */
					cds_wfcq_enqueue(&notifiers->ust_cmd_queue->head,
							&notifiers->ust_cmd_queue->tail,
							&ust_cmd->node);

					/*
					 * Wake the registration queue futex. Implicit memory
					 * barrier with the exchange in cds_wfcq_enqueue.
					 */
					futex_nto1_wake(&notifiers->ust_cmd_queue->futex);
				} else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
					ERR("Register apps socket poll error");
					goto error;
				} else {
					ERR("Unexpected poll events %u for sock %d", revents, pollfd);
					goto error;
				}
			}
		}
	}

exit:
error:
	/* Notify that the registration thread is gone */
	notify_ust_apps(0, is_root);

	if (apps_sock >= 0) {
		ret = close(apps_sock);
		if (ret) {
			PERROR("close");
		}
	}
	if (sock >= 0) {
		ret = close(sock);
		if (ret) {
			PERROR("close");
		}
		lttng_fd_put(LTTNG_FD_APPS, 1);
	}
	unlink(config.apps_unix_sock_path.value);

error_poll_add:
	lttng_poll_clean(&events);
error_listen:
error_create_poll:
	DBG("UST Registration thread cleanup complete");
	if (err) {
		health_error();
		ERR("Health error occurred in %s", __func__);
	}
	health_unregister(health_sessiond);
	return NULL;
}

static bool shutdown_application_registration_thread(void *data)
{
	struct thread_notifiers *notifiers = data;
	const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe);

	return notify_thread_pipe(write_fd) == 1;
}

struct lttng_thread *launch_application_registration_thread(
		struct ust_cmd_queue *cmd_queue)
{
	struct lttng_pipe *quit_pipe;
	struct thread_notifiers *notifiers = NULL;
	struct lttng_thread *thread;

	notifiers = zmalloc(sizeof(*notifiers));
	if (!notifiers) {
		goto error_alloc;
	}
	quit_pipe = lttng_pipe_open(FD_CLOEXEC);
	if (!quit_pipe) {
		goto error;
	}
	notifiers->quit_pipe = quit_pipe;
	notifiers->ust_cmd_queue = cmd_queue;
	sem_init(&notifiers->ready, 0, 0);

	thread = lttng_thread_create("UST application registration",
			thread_application_registration,
			shutdown_application_registration_thread,
			cleanup_application_registration_thread,
			notifiers);
	if (!thread) {
		goto error;
	}
	if (!wait_thread_status(notifiers)) {
		lttng_thread_put(thread);
		thread = NULL;
	}
	return thread;
error:
	cleanup_application_registration_thread(notifiers);
error_alloc:
	return NULL;
}
Commit	Line	Data
1785d7f2 JG	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	* 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License, version 2 only,
	8	* as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along
	16	* with this program; if not, write to the Free Software Foundation, Inc.,
	17	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	18	*/
	19
	20	#include <stddef.h>
	21	#include <stdlib.h>
	22	#include <urcu.h>
	23	#include <common/futex.h>
	24	#include <common/macros.h>
	25	#include <common/utils.h>
	26	#include <sys/stat.h>
	27
	28	#include "register.h"
	29	#include "lttng-sessiond.h"
	30	#include "testpoint.h"
	31	#include "health-sessiond.h"
	32	#include "fd-limit.h"
	33	#include "shm.h"
	34	#include "utils.h"
	35	#include "thread.h"
	36
	37	struct thread_notifiers {
	38	struct lttng_pipe *quit_pipe;
	39	struct ust_cmd_queue *ust_cmd_queue;
9c9d917c	40	sem_t ready;
86d0f119	41	bool running;
1785d7f2 JG	42	};
	43
	44	/*
	45	* Creates the application socket.
	46	*/
	47	static int create_application_socket(void)
	48	{
	49	int ret = 0;
	50	int apps_sock;
	51	const mode_t old_umask = umask(0);
	52
	53	/* Create the application unix socket */
	54	apps_sock = lttcomm_create_unix_sock(config.apps_unix_sock_path.value);
	55	if (apps_sock < 0) {
	56	ERR("Create unix sock failed: %s", config.apps_unix_sock_path.value);
	57	ret = -1;
	58	goto end;
	59	}
	60
	61	/* Set the cloexec flag */
	62	ret = utils_set_fd_cloexec(apps_sock);
	63	if (ret < 0) {
	64	ERR("Unable to set CLOEXEC flag to the app Unix socket (fd: %d). "
	65	"Continuing but note that the consumer daemon will have a "
	66	"reference to this socket on exec()", apps_sock);
	67	}
	68
	69	/* File permission MUST be 666 */
	70	ret = chmod(config.apps_unix_sock_path.value,
	71	S_IRUSR \| S_IWUSR \| S_IRGRP \| S_IWGRP \| S_IROTH \| S_IWOTH);
	72	if (ret < 0) {
	73	PERROR("Set file permissions failed on %s",
	74	config.apps_unix_sock_path.value);
	75	goto end;
	76	}
	77
	78	DBG3("Session daemon application socket created (fd = %d) ", apps_sock);
	79	ret = apps_sock;
	80	end:
	81	umask(old_umask);
	82	return ret;
	83	}
	84
	85	/*
	86	* Notify UST applications using the shm mmap futex.
	87	*/
	88	static int notify_ust_apps(int active, bool is_root)
	89	{
	90	char *wait_shm_mmap;
	91
	92	DBG("Notifying applications of session daemon state: %d", active);
	93
	94	/* See shm.c for this call implying mmap, shm and futex calls */
	95	wait_shm_mmap = shm_ust_get_mmap(config.wait_shm_path.value, is_root);
	96	if (wait_shm_mmap == NULL) {
	97	goto error;
	98	}
	99
	100	/* Wake waiting process */
	101	futex_wait_update((int32_t *) wait_shm_mmap, active);
	102
	103	/* Apps notified successfully */
	104	return 0;
	105
106	error:
107	return -1;
108	}
109
110	static void cleanup_application_registration_thread(void *data)
111	{
112	struct thread_notifiers *notifiers = data;
113
114	lttng_pipe_destroy(notifiers->quit_pipe);
115	free(notifiers);
116	}
117
86d0f119	118	static void set_thread_status(struct thread_notifiers *notifiers, bool running)
9c9d917c	119	{
86d0f119 JG	120	DBG("Marking application registration thread's state as %s", running ? "running" : "error");
86d0f119 JG	121	notifiers->running = running;
9c9d917c JG	122	sem_post(&notifiers->ready);
	123	}
	124
86d0f119	125	static bool wait_thread_status(struct thread_notifiers *notifiers)
9c9d917c JG	126	{
	127	DBG("Waiting for application registration thread to be ready");
	128	sem_wait(&notifiers->ready);
86d0f119 JG	129	if (notifiers->running) {
	130	DBG("Application registration thread is ready");
	131	} else {
	132	ERR("Initialization of application registration thread failed");
	133	}
	134
	135	return notifiers->running;
	136	}
	137
	138	static void thread_init_cleanup(void *data)
	139	{
	140	struct thread_notifiers *notifiers = data;
	141
	142	set_thread_status(notifiers, false);
9c9d917c JG	143	}
9c9d917c JG	144
1785d7f2 JG	145	/*
	146	* This thread manage application registration.
	147	*/
	148	static void thread_application_registration(void data)
	149	{
	150	int sock = -1, i, ret, pollfd, err = -1;
	151	int apps_sock = -1;
	152	uint32_t revents, nb_fd;
	153	struct lttng_poll_event events;
	154	/*
	155	* Gets allocated in this thread, enqueued to a global queue, dequeued
	156	* and freed in the manage apps thread.
	157	*/
	158	struct ust_command *ust_cmd = NULL;
	159	const bool is_root = (getuid() == 0);
	160	struct thread_notifiers *notifiers = data;
	161	const int quit_pipe_read_fd = lttng_pipe_get_readfd(
	162	notifiers->quit_pipe);
	163
	164	DBG("[thread] Manage application registration started");
	165
86d0f119	166	pthread_cleanup_push(thread_init_cleanup, NULL);
1785d7f2 JG	167	health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG);
1785d7f2 JG	168
1785d7f2 JG	169	apps_sock = create_application_socket();
	170	if (apps_sock < 0) {
	171	goto error_listen;
	172	}
	173
	174	ret = lttcomm_listen_unix_sock(apps_sock);
	175	if (ret < 0) {
	176	goto error_listen;
	177	}
	178
86d0f119 JG	179	set_thread_status(notifiers, true);
	180	pthread_cleanup_pop(0);
	181
	182	if (testpoint(sessiond_thread_registration_apps)) {
	183	goto error_create_poll;
	184	}
9c9d917c	185
1785d7f2 JG	186	/*
	187	* Pass 2 as size here for the thread quit pipe and apps_sock. Nothing
	188	* more will be added to this poll set.
	189	*/
	190	ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
	191	if (ret < 0) {
	192	goto error_create_poll;
	193	}
	194
	195	/* Add the application registration socket */
	196	ret = lttng_poll_add(&events, apps_sock, LPOLLIN \| LPOLLRDHUP);
	197	if (ret < 0) {
	198	goto error_poll_add;
	199	}
	200
	201	/* Add the application registration socket */
	202	ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN \| LPOLLRDHUP);
	203	if (ret < 0) {
	204	goto error_poll_add;
	205	}
	206
	207	/* Notify all applications to register */
	208	ret = notify_ust_apps(1, is_root);
	209	if (ret < 0) {
	210	ERR("Failed to notify applications or create the wait shared memory.\n"
	211	"Execution continues but there might be problem for already\n"
	212	"running applications that wishes to register.");
	213	}
	214
	215	while (1) {
	216	DBG("Accepting application registration");
	217
	218	/* Inifinite blocking call, waiting for transmission */
	219	restart:
	220	health_poll_entry();
	221	ret = lttng_poll_wait(&events, -1);
	222	health_poll_exit();
	223	if (ret < 0) {
	224	/*
	225	* Restart interrupted system call.
	226	*/
	227	if (errno == EINTR) {
	228	goto restart;
	229	}
	230	goto error;
	231	}
	232
	233	nb_fd = ret;
	234
	235	for (i = 0; i < nb_fd; i++) {
	236	health_code_update();
	237
	238	/* Fetch once the poll data */
	239	revents = LTTNG_POLL_GETEV(&events, i);
	240	pollfd = LTTNG_POLL_GETFD(&events, i);
	241
1785d7f2 JG	242	/* Thread quit pipe has been closed. Killing thread. */
	243	if (pollfd == quit_pipe_read_fd) {
	244	err = 0;
	245	goto exit;
	246	} else {
	247	/* Event on the registration socket */
	248	if (revents & LPOLLIN) {
	249	sock = lttcomm_accept_unix_sock(apps_sock);
	250	if (sock < 0) {
	251	goto error;
	252	}
	253
	254	/*
	255	* Set socket timeout for both receiving and ending.
	256	* app_socket_timeout is in seconds, whereas
	257	* lttcomm_setsockopt_rcv_timeout and
	258	* lttcomm_setsockopt_snd_timeout expect msec as
	259	* parameter.
	260	*/
	261	if (config.app_socket_timeout >= 0) {
	262	(void) lttcomm_setsockopt_rcv_timeout(sock,
	263	config.app_socket_timeout * 1000);
	264	(void) lttcomm_setsockopt_snd_timeout(sock,
	265	config.app_socket_timeout * 1000);
	266	}
	267
	268	/*
	269	* Set the CLOEXEC flag. Return code is useless because
	270	* either way, the show must go on.
	271	*/
	272	(void) utils_set_fd_cloexec(sock);
	273
	274	/* Create UST registration command for enqueuing */
	275	ust_cmd = zmalloc(sizeof(struct ust_command));
	276	if (ust_cmd == NULL) {
	277	PERROR("ust command zmalloc");
	278	ret = close(sock);
	279	if (ret) {
	280	PERROR("close");
	281	}
	282	goto error;
	283	}
	284
	285	/*
	286	* Using message-based transmissions to ensure we don't
	287	* have to deal with partially received messages.
	288	*/
	289	ret = lttng_fd_get(LTTNG_FD_APPS, 1);
	290	if (ret < 0) {
	291	ERR("Exhausted file descriptors allowed for applications.");
	292	free(ust_cmd);
	293	ret = close(sock);
	294	if (ret) {
	295	PERROR("close");
	296	}
	297	sock = -1;
	298	continue;
	299	}
	300
	301	health_code_update();
	302	ret = ust_app_recv_registration(sock, &ust_cmd->reg_msg);
	303	if (ret < 0) {
	304	free(ust_cmd);
	305	/* Close socket of the application. */
306	ret = close(sock);
307	if (ret) {
308	PERROR("close");
309	}
310	lttng_fd_put(LTTNG_FD_APPS, 1);
311	sock = -1;
312	continue;
313	}
314	health_code_update();
315
316	ust_cmd->sock = sock;
317	sock = -1;
318
319	DBG("UST registration received with pid:%d ppid:%d uid:%d"
320	" gid:%d sock:%d name:%s (version %d.%d)",
321	ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid,
322	ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid,
323	ust_cmd->sock, ust_cmd->reg_msg.name,
324	ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor);
325
326	/*
327	* Lock free enqueue the registration request. The red pill
328	* has been taken! This apps will be part of the system.
329	*/
330	cds_wfcq_enqueue(&notifiers->ust_cmd_queue->head,
331	&notifiers->ust_cmd_queue->tail,
332	&ust_cmd->node);
333
334	/*
335	* Wake the registration queue futex. Implicit memory
336	* barrier with the exchange in cds_wfcq_enqueue.
337	*/
338	futex_nto1_wake(&notifiers->ust_cmd_queue->futex);
339	} else if (revents & (LPOLLERR \| LPOLLHUP \| LPOLLRDHUP)) {
340	ERR("Register apps socket poll error");
341	goto error;
342	} else {
343	ERR("Unexpected poll events %u for sock %d", revents, pollfd);
344	goto error;
345	}
346	}
347	}
348	}
349
350	exit:
351	error:
352	/* Notify that the registration thread is gone */
353	notify_ust_apps(0, is_root);
354
355	if (apps_sock >= 0) {
356	ret = close(apps_sock);
357	if (ret) {
358	PERROR("close");
359	}
360	}
361	if (sock >= 0) {
362	ret = close(sock);
363	if (ret) {
364	PERROR("close");
365	}
366	lttng_fd_put(LTTNG_FD_APPS, 1);
367	}
368	unlink(config.apps_unix_sock_path.value);
369
370	error_poll_add:
371	lttng_poll_clean(&events);
372	error_listen:
373	error_create_poll:
1785d7f2 JG	374	DBG("UST Registration thread cleanup complete");
	375	if (err) {
	376	health_error();
	377	ERR("Health error occurred in %s", __func__);
	378	}
	379	health_unregister(health_sessiond);
	380	return NULL;
	381	}
	382
	383	static bool shutdown_application_registration_thread(void *data)
	384	{
	385	struct thread_notifiers *notifiers = data;
	386	const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe);
	387
	388	return notify_thread_pipe(write_fd) == 1;
	389	}
	390
bd9addf7	391	struct lttng_thread *launch_application_registration_thread(
1785d7f2 JG	392	struct ust_cmd_queue *cmd_queue)
	393	{
	394	struct lttng_pipe *quit_pipe;
	395	struct thread_notifiers *notifiers = NULL;
	396	struct lttng_thread *thread;
	397
1785d7f2 JG	398	notifiers = zmalloc(sizeof(*notifiers));
1785d7f2 JG	399	if (!notifiers) {
21fa020e JG	400	goto error_alloc;
	401	}
	402	quit_pipe = lttng_pipe_open(FD_CLOEXEC);
	403	if (!quit_pipe) {
1785d7f2 JG	404	goto error;
	405	}
	406	notifiers->quit_pipe = quit_pipe;
	407	notifiers->ust_cmd_queue = cmd_queue;
9c9d917c	408	sem_init(&notifiers->ready, 0, 0);
1785d7f2 JG	409
	410	thread = lttng_thread_create("UST application registration",
	411	thread_application_registration,
	412	shutdown_application_registration_thread,
	413	cleanup_application_registration_thread,
	414	notifiers);
	415	if (!thread) {
	416	goto error;
	417	}
86d0f119 JG	418	if (!wait_thread_status(notifiers)) {
	419	lttng_thread_put(thread);
	420	thread = NULL;
	421	}
bd9addf7	422	return thread;
1785d7f2 JG	423	error:
1785d7f2 JG	424	cleanup_application_registration_thread(notifiers);
21fa020e	425	error_alloc:
bd9addf7	426	return NULL;
1785d7f2	427	}