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

/*
 * Copyright (C) 2013 - David Goulet <dgoulet@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.
 */

#define _GNU_SOURCE
#include <assert.h>

#include <common/common.h>
#include <common/sessiond-comm/sessiond-comm.h>
#include <common/uri.h>
#include <common/utils.h>

#include "fd-limit.h"
#include "jul-thread.h"
#include "lttng-sessiond.h"
#include "session.h"
#include "utils.h"

/*
 * Note that there is not port here. It's set after this URI is parsed so we
 * can let the user define a custom one. However, localhost is ALWAYS the
 * default listening address.
 */
static const char *default_reg_uri = "tcp://localhost";

/*
 * Update JUL application using the given socket. This is done just after
 * registration was successful.
 *
 * This is a quite heavy call in terms of locking since the session list lock
 * AND session lock are acquired.
 */
static void update_jul_app(int sock)
{
	struct ltt_session *session, *stmp;
	struct ltt_session_list *list;

	list = session_get_list();
	assert(list);

	session_lock_list();
	cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
		session_lock(session);
		if (session->ust_session) {
			jul_update(&session->ust_session->domain_jul, sock);
		}
		session_unlock(session);
	}
	session_unlock_list();
}

/*
 * Destroy a JUL application by socket.
 */
static void destroy_jul_app(int sock)
{
	struct jul_app *app;

	assert(sock >= 0);

	/*
	 * Not finding an application is a very important error that should NEVER
	 * happen. The hash table deletion is ONLY done through this call even on
	 * thread cleanup.
	 */
	rcu_read_lock();
	app = jul_find_app_by_sock(sock);
	assert(app);
	rcu_read_unlock();

	/* RCU read side lock is taken in this function call. */
	jul_delete_app(app);

	/* The application is freed in a RCU call but the socket is closed here. */
	jul_destroy_app(app);
}

/*
 * Cleanup remaining JUL apps in the hash table. This should only be called in
 * the exit path of the thread.
 */
static void clean_jul_apps_ht(void)
{
	struct lttng_ht_node_ulong *node;
	struct lttng_ht_iter iter;

	DBG3("[jul-thread] Cleaning JUL apps ht");

	rcu_read_lock();
	cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, node, node) {
		struct jul_app *app;

		app = caa_container_of(node, struct jul_app, node);
		destroy_jul_app(app->sock->fd);
	}
	rcu_read_unlock();
}

/*
 * Create and init socket from uri.
 */
static struct lttcomm_sock *init_tcp_socket(void)
{
	int ret;
	struct lttng_uri *uri = NULL;
	struct lttcomm_sock *sock = NULL;

	/*
	 * This should never fail since the URI is hardcoded and the port is set
	 * before this thread is launched.
	 */
	ret = uri_parse(default_reg_uri, &uri);
	assert(ret);
	assert(jul_tcp_port);
	uri->port = jul_tcp_port;

	sock = lttcomm_alloc_sock_from_uri(uri);
	uri_free(uri);
	if (sock == NULL) {
		ERR("[jul-thread] JUL allocating TCP socket");
		goto error;
	}

	ret = lttcomm_create_sock(sock);
	if (ret < 0) {
		goto error;
	}

	ret = sock->ops->bind(sock);
	if (ret < 0) {
		WARN("An other session daemon is using this JUL port. JUL support "
				"will be deactivated not interfering with the tracing.");
		goto error;
	}

	ret = sock->ops->listen(sock, -1);
	if (ret < 0) {
		goto error;
	}

	DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
			sock->fd);

	return sock;

error:
	if (sock) {
		lttcomm_destroy_sock(sock);
	}
	return NULL;
}

/*
 * Close and destroy the given TCP socket.
 */
static void destroy_tcp_socket(struct lttcomm_sock *sock)
{
	assert(sock);

	DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);

	/* This will return gracefully if fd is invalid. */
	sock->ops->close(sock);
	lttcomm_destroy_sock(sock);
}

/*
 * Handle a new JUL registration using the reg socket. After that, a new JUL
 * application is added to the global hash table and attach to an UST app
 * object.
 *
 * Return the new FD created upon accept() on success or else a negative errno
 * value.
 */
static int handle_registration(struct lttcomm_sock *reg_sock)
{
	int ret;
	pid_t pid;
	ssize_t size;
	struct jul_app *app;
	struct jul_register_msg msg;
	struct lttcomm_sock *new_sock;

	assert(reg_sock);

	new_sock = reg_sock->ops->accept(reg_sock);
	if (!new_sock) {
		ret = -ENOTCONN;
		goto error;
	}

	size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
	if (size < sizeof(msg)) {
		ret = -errno;
		goto error_socket;
	}
	pid = be32toh(msg.pid);

	DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
			new_sock->fd);

	app = jul_create_app(pid, new_sock);
	if (!app) {
		ret = -ENOMEM;
		goto error_socket;
	}

	/*
	 * Add before assigning the socket value to the UST app so it can be found
	 * concurrently.
	 */
	jul_add_app(app);

	/*
	 * We don't need to attach the JUL app to the app. If we ever do
	 * so, we should consider both registration order of JUL before
	 * app and app before JUL.
	 */

	return new_sock->fd;

error_socket:
	new_sock->ops->close(new_sock);
	lttcomm_destroy_sock(new_sock);
error:
	return ret;
}

/*
 * This thread manage application notify communication.
 */
void *jul_thread_manage_registration(void *data)
{
	int i, ret, pollfd;
	uint32_t revents, nb_fd;
	struct lttng_poll_event events;
	struct lttcomm_sock *reg_sock;

	DBG("[jul-thread] Manage JUL application registration.");

	rcu_register_thread();
	rcu_thread_online();

	/* JUL initialization call MUST be called before starting the thread. */
	assert(jul_apps_ht_by_sock);

	/* Create pollset with size 2, quit pipe and socket. */
	ret = sessiond_set_thread_pollset(&events, 2);
	if (ret < 0) {
		goto error_poll_create;
	}

	reg_sock = init_tcp_socket();
	if (!reg_sock) {
		goto error_tcp_socket;
	}

	/* Add create valid TCP socket to poll set. */
	ret = lttng_poll_add(&events, reg_sock->fd,
			LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
	if (ret < 0) {
		goto error;
	}

	while (1) {
		DBG3("[jul-thread] Manage JUL polling on %d fds",
				LTTNG_POLL_GETNB(&events));

		/* Inifinite blocking call, waiting for transmission */
restart:
		ret = lttng_poll_wait(&events, -1);
		if (ret < 0) {
			/*
			 * Restart interrupted system call.
			 */
			if (errno == EINTR) {
				goto restart;
			}
			goto error;
		}
		nb_fd = ret;
		DBG3("[jul-thread] %d fd ready", nb_fd);

		for (i = 0; i < nb_fd; i++) {
			/* 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. */
			ret = sessiond_check_thread_quit_pipe(pollfd, revents);
			if (ret) {
				goto exit;
			}

			/*
			 * Check first if this is a POLLERR since POLLIN is also included
			 * in an error value thus checking first.
			 */
			if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
				/* Removing from the poll set */
				ret = lttng_poll_del(&events, pollfd);
				if (ret < 0) {
					goto error;
				}

				destroy_jul_app(pollfd);
			} else if (revents & (LPOLLIN)) {
				int new_fd;

				/* Pollin event of JUL app socket should NEVER happen. */
				assert(pollfd == reg_sock->fd);

				new_fd = handle_registration(reg_sock);
				if (new_fd < 0) {
					WARN("[jul-thread] JUL registration failed. Ignoring.");
					/* Somehow the communication failed. Just continue. */
					continue;
				}

				/* Only add poll error event to only detect shutdown. */
				ret = lttng_poll_add(&events, new_fd,
						LPOLLERR | LPOLLHUP | LPOLLRDHUP);
				if (ret < 0) {
					destroy_jul_app(new_fd);
					continue;
				}

				/* Update newly registered app. */
				update_jul_app(new_fd);
			} else {
				ERR("Unknown poll events %u for sock %d", revents, pollfd);
				continue;
			}
		}
	}

exit:
	/* Whatever happens, try to delete it and exit. */
	(void) lttng_poll_del(&events, reg_sock->fd);
error:
	destroy_tcp_socket(reg_sock);
error_tcp_socket:
	lttng_poll_clean(&events);
error_poll_create:
	DBG("[jul-thread] is cleaning up and stopping.");

	if (jul_apps_ht_by_sock) {
		clean_jul_apps_ht();
		lttng_ht_destroy(jul_apps_ht_by_sock);
	}

	rcu_thread_offline();
	rcu_unregister_thread();
	return NULL;
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License, version 2 only, as
	6	* published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along with
	14	* this program; if not, write to the Free Software Foundation, Inc., 51
	15	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	16	*/
	17
	18	#define _GNU_SOURCE
	19	#include <assert.h>
	20
	21	#include <common/common.h>
	22	#include <common/sessiond-comm/sessiond-comm.h>
	23	#include <common/uri.h>
	24	#include <common/utils.h>
	25
	26	#include "fd-limit.h"
	27	#include "jul-thread.h"
	28	#include "lttng-sessiond.h"
	29	#include "session.h"
	30	#include "utils.h"
	31
	32	/*
	33	* Note that there is not port here. It's set after this URI is parsed so we
	34	* can let the user define a custom one. However, localhost is ALWAYS the
	35	* default listening address.
	36	*/
	37	static const char *default_reg_uri = "tcp://localhost";
	38
	39	/*
	40	* Update JUL application using the given socket. This is done just after
	41	* registration was successful.
	42	*
	43	* This is a quite heavy call in terms of locking since the session list lock
	44	* AND session lock are acquired.
	45	*/
	46	static void update_jul_app(int sock)
	47	{
	48	struct ltt_session session, stmp;
	49	struct ltt_session_list *list;
	50
	51	list = session_get_list();
	52	assert(list);
	53
	54	session_lock_list();
	55	cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
	56	session_lock(session);
	57	if (session->ust_session) {
	58	jul_update(&session->ust_session->domain_jul, sock);
	59	}
	60	session_unlock(session);
	61	}
	62	session_unlock_list();
	63	}
	64
	65	/*
	66	* Destroy a JUL application by socket.
	67	*/
	68	static void destroy_jul_app(int sock)
	69	{
	70	struct jul_app *app;
	71
	72	assert(sock >= 0);
	73
	74	/*
	75	* Not finding an application is a very important error that should NEVER
	76	* happen. The hash table deletion is ONLY done through this call even on
	77	* thread cleanup.
	78	*/
	79	rcu_read_lock();
	80	app = jul_find_app_by_sock(sock);
	81	assert(app);
	82	rcu_read_unlock();
	83
	84	/* RCU read side lock is taken in this function call. */
	85	jul_delete_app(app);
	86
	87	/* The application is freed in a RCU call but the socket is closed here. */
	88	jul_destroy_app(app);
	89	}
	90
	91	/*
	92	* Cleanup remaining JUL apps in the hash table. This should only be called in
	93	* the exit path of the thread.
	94	*/
	95	static void clean_jul_apps_ht(void)
	96	{
	97	struct lttng_ht_node_ulong *node;
	98	struct lttng_ht_iter iter;
	99
	100	DBG3("[jul-thread] Cleaning JUL apps ht");
	101
	102	rcu_read_lock();
	103	cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, node, node) {
	104	struct jul_app *app;
	105
	106	app = caa_container_of(node, struct jul_app, node);
	107	destroy_jul_app(app->sock->fd);
	108	}
	109	rcu_read_unlock();
	110	}
	111
	112	/*
	113	* Create and init socket from uri.
	114	*/
	115	static struct lttcomm_sock *init_tcp_socket(void)
	116	{
	117	int ret;
	118	struct lttng_uri *uri = NULL;
	119	struct lttcomm_sock *sock = NULL;
	120
	121	/*
	122	* This should never fail since the URI is hardcoded and the port is set
	123	* before this thread is launched.
	124	*/
	125	ret = uri_parse(default_reg_uri, &uri);
	126	assert(ret);
	127	assert(jul_tcp_port);
	128	uri->port = jul_tcp_port;
	129
	130	sock = lttcomm_alloc_sock_from_uri(uri);
	131	uri_free(uri);
	132	if (sock == NULL) {
	133	ERR("[jul-thread] JUL allocating TCP socket");
	134	goto error;
	135	}
	136
	137	ret = lttcomm_create_sock(sock);
	138	if (ret < 0) {
	139	goto error;
	140	}
	141
	142	ret = sock->ops->bind(sock);
	143	if (ret < 0) {
	144	WARN("An other session daemon is using this JUL port. JUL support "
	145	"will be deactivated not interfering with the tracing.");
	146	goto error;
	147	}
	148
	149	ret = sock->ops->listen(sock, -1);
	150	if (ret < 0) {
	151	goto error;
	152	}
	153
	154	DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
	155	sock->fd);
	156
	157	return sock;
	158
	159	error:
	160	if (sock) {
	161	lttcomm_destroy_sock(sock);
	162	}
	163	return NULL;
	164	}
	165
	166	/*
	167	* Close and destroy the given TCP socket.
	168	*/
	169	static void destroy_tcp_socket(struct lttcomm_sock *sock)
	170	{
	171	assert(sock);
	172
	173	DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);
	174
	175	/* This will return gracefully if fd is invalid. */
	176	sock->ops->close(sock);
	177	lttcomm_destroy_sock(sock);
	178	}
	179
	180	/*
	181	* Handle a new JUL registration using the reg socket. After that, a new JUL
	182	* application is added to the global hash table and attach to an UST app
	183	* object.
	184	*
	185	* Return the new FD created upon accept() on success or else a negative errno
	186	* value.
	187	*/
	188	static int handle_registration(struct lttcomm_sock *reg_sock)
	189	{
	190	int ret;
	191	pid_t pid;
	192	ssize_t size;
	193	struct jul_app *app;
	194	struct jul_register_msg msg;
	195	struct lttcomm_sock *new_sock;
	196
	197	assert(reg_sock);
	198
	199	new_sock = reg_sock->ops->accept(reg_sock);
	200	if (!new_sock) {
	201	ret = -ENOTCONN;
	202	goto error;
	203	}
	204
	205	size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
	206	if (size < sizeof(msg)) {
	207	ret = -errno;
	208	goto error_socket;
	209	}
	210	pid = be32toh(msg.pid);
	211
	212	DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
	213	new_sock->fd);
	214
	215	app = jul_create_app(pid, new_sock);
	216	if (!app) {
	217	ret = -ENOMEM;
	218	goto error_socket;
	219	}
	220
	221	/*
	222	* Add before assigning the socket value to the UST app so it can be found
	223	* concurrently.
	224	*/
	225	jul_add_app(app);
	226
	227	/*
	228	* We don't need to attach the JUL app to the app. If we ever do
	229	* so, we should consider both registration order of JUL before
	230	* app and app before JUL.
	231	*/
	232
	233	return new_sock->fd;
	234
	235	error_socket:
	236	new_sock->ops->close(new_sock);
	237	lttcomm_destroy_sock(new_sock);
	238	error:
	239	return ret;
	240	}
	241
	242	/*
	243	* This thread manage application notify communication.
	244	*/
	245	void jul_thread_manage_registration(void data)
	246	{
	247	int i, ret, pollfd;
	248	uint32_t revents, nb_fd;
	249	struct lttng_poll_event events;
	250	struct lttcomm_sock *reg_sock;
	251
	252	DBG("[jul-thread] Manage JUL application registration.");
	253
	254	rcu_register_thread();
	255	rcu_thread_online();
	256
	257	/* JUL initialization call MUST be called before starting the thread. */
	258	assert(jul_apps_ht_by_sock);
	259
	260	/* Create pollset with size 2, quit pipe and socket. */
	261	ret = sessiond_set_thread_pollset(&events, 2);
	262	if (ret < 0) {
	263	goto error_poll_create;
	264	}
	265
	266	reg_sock = init_tcp_socket();
	267	if (!reg_sock) {
	268	goto error_tcp_socket;
	269	}
	270
	271	/* Add create valid TCP socket to poll set. */
	272	ret = lttng_poll_add(&events, reg_sock->fd,
	273	LPOLLIN \| LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	274	if (ret < 0) {
	275	goto error;
	276	}
	277
	278	while (1) {
	279	DBG3("[jul-thread] Manage JUL polling on %d fds",
	280	LTTNG_POLL_GETNB(&events));
	281
	282	/* Inifinite blocking call, waiting for transmission */
	283	restart:
	284	ret = lttng_poll_wait(&events, -1);
	285	if (ret < 0) {
	286	/*
	287	* Restart interrupted system call.
	288	*/
	289	if (errno == EINTR) {
	290	goto restart;
	291	}
	292	goto error;
	293	}
	294	nb_fd = ret;
	295	DBG3("[jul-thread] %d fd ready", nb_fd);
	296
	297	for (i = 0; i < nb_fd; i++) {
	298	/* Fetch once the poll data */
	299	revents = LTTNG_POLL_GETEV(&events, i);
	300	pollfd = LTTNG_POLL_GETFD(&events, i);
	301
	302	/* Thread quit pipe has been closed. Killing thread. */
	303	ret = sessiond_check_thread_quit_pipe(pollfd, revents);
	304	if (ret) {
	305	goto exit;
	306	}
	307
	308	/*
	309	* Check first if this is a POLLERR since POLLIN is also included
	310	* in an error value thus checking first.
	311	*/
	312	if (revents & (LPOLLERR \| LPOLLHUP \| LPOLLRDHUP)) {
	313	/* Removing from the poll set */
	314	ret = lttng_poll_del(&events, pollfd);
	315	if (ret < 0) {
	316	goto error;
	317	}
	318
	319	destroy_jul_app(pollfd);
	320	} else if (revents & (LPOLLIN)) {
	321	int new_fd;
	322
	323	/* Pollin event of JUL app socket should NEVER happen. */
	324	assert(pollfd == reg_sock->fd);
	325
	326	new_fd = handle_registration(reg_sock);
	327	if (new_fd < 0) {
	328	WARN("[jul-thread] JUL registration failed. Ignoring.");
	329	/* Somehow the communication failed. Just continue. */
	330	continue;
	331	}
	332
	333	/* Only add poll error event to only detect shutdown. */
	334	ret = lttng_poll_add(&events, new_fd,
	335	LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	336	if (ret < 0) {
	337	destroy_jul_app(new_fd);
	338	continue;
	339	}
	340
	341	/* Update newly registered app. */
	342	update_jul_app(new_fd);
	343	} else {
	344	ERR("Unknown poll events %u for sock %d", revents, pollfd);
	345	continue;
	346	}
	347	}
	348	}
	349
	350	exit:
	351	/* Whatever happens, try to delete it and exit. */
	352	(void) lttng_poll_del(&events, reg_sock->fd);
	353	error:
	354	destroy_tcp_socket(reg_sock);
	355	error_tcp_socket:
	356	lttng_poll_clean(&events);
	357	error_poll_create:
	358	DBG("[jul-thread] is cleaning up and stopping.");
	359
	360	if (jul_apps_ht_by_sock) {
	361	clean_jul_apps_ht();
	362	lttng_ht_destroy(jul_apps_ht_by_sock);
	363	}
	364
	365	rcu_thread_offline();
	366	rcu_unregister_thread();
	367	return NULL;
	368	}