[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) {
		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);

	/*
	 * Attach JUL application to a UST app object if one exists.
	 *
	 * FIXME: This implies that the UST app object exists and created before
	 * JUL registration. Must confirm or else JUL app will leak until socket is
	 * closed by the application.
	 */
	jul_attach_app(app);

	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;
				}

				/*
				 * FIXME: Should we try to invalidate the JUL socket in the
				 * associated ust app.
				 */
				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
4d076222 DG	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"
f20baf8e DG	29	#include "session.h"
f20baf8e DG	30	#include "utils.h"
4d076222 DG	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
f20baf8e DG	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
4d076222 DG	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	goto error;
	145	}
	146
	147	ret = sock->ops->listen(sock, -1);
	148	if (ret < 0) {
	149	goto error;
	150	}
	151
	152	DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
	153	sock->fd);
	154
	155	return sock;
	156
	157	error:
	158	if (sock) {
	159	lttcomm_destroy_sock(sock);
	160	}
	161	return NULL;
	162	}
	163
	164	/*
	165	* Close and destroy the given TCP socket.
	166	*/
	167	static void destroy_tcp_socket(struct lttcomm_sock *sock)
	168	{
	169	assert(sock);
	170
	171	DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);
	172
	173	/* This will return gracefully if fd is invalid. */
	174	sock->ops->close(sock);
	175	lttcomm_destroy_sock(sock);
176	}
177
f20baf8e DG	178	/*
	179	* Handle a new JUL registration using the reg socket. After that, a new JUL
	180	* application is added to the global hash table and attach to an UST app
	181	* object.
	182	*
	183	* Return the new FD created upon accept() on success or else a negative errno
	184	* value.
	185	*/
	186	static int handle_registration(struct lttcomm_sock *reg_sock)
	187	{
	188	int ret;
	189	pid_t pid;
	190	ssize_t size;
	191	struct jul_app *app;
	192	struct jul_register_msg msg;
	193	struct lttcomm_sock *new_sock;
	194
	195	assert(reg_sock);
	196
	197	new_sock = reg_sock->ops->accept(reg_sock);
	198	if (!new_sock) {
	199	ret = -ENOTCONN;
	200	goto error;
	201	}
	202
	203	size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
	204	if (size < sizeof(msg)) {
	205	ret = -errno;
	206	goto error_socket;
	207	}
	208	pid = be32toh(msg.pid);
	209
	210	DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
	211	new_sock->fd);
	212
	213	app = jul_create_app(pid, new_sock);
	214	if (!app) {
	215	ret = -ENOMEM;
	216	goto error_socket;
	217	}
	218
	219	/*
	220	* Add before assigning the socket value to the UST app so it can be found
	221	* concurrently.
	222	*/
	223	jul_add_app(app);
	224
	225	/*
	226	* Attach JUL application to a UST app object if one exists.
	227	*
	228	* FIXME: This implies that the UST app object exists and created before
	229	* JUL registration. Must confirm or else JUL app will leak until socket is
	230	* closed by the application.
	231	*/
	232	jul_attach_app(app);
	233
	234	return new_sock->fd;
	235
	236	error_socket:
	237	new_sock->ops->close(new_sock);
	238	lttcomm_destroy_sock(new_sock);
	239	error:
	240	return ret;
	241	}
242
4d076222 DG	243	/*
	244	* This thread manage application notify communication.
	245	*/
	246	void jul_thread_manage_registration(void data)
	247	{
	248	int i, ret, pollfd;
	249	uint32_t revents, nb_fd;
	250	struct lttng_poll_event events;
	251	struct lttcomm_sock *reg_sock;
	252
	253	DBG("[jul-thread] Manage JUL application registration.");
	254
	255	rcu_register_thread();
	256	rcu_thread_online();
	257
f20baf8e DG	258	/* JUL initialization call MUST be called before starting the thread. */
	259	assert(jul_apps_ht_by_sock);
	260
4d076222 DG	261	/* Create pollset with size 2, quit pipe and socket. */
	262	ret = sessiond_set_thread_pollset(&events, 2);
	263	if (ret < 0) {
	264	goto error_poll_create;
	265	}
	266
	267	reg_sock = init_tcp_socket();
	268	if (!reg_sock) {
	269	goto error_tcp_socket;
	270	}
	271
	272	/* Add create valid TCP socket to poll set. */
	273	ret = lttng_poll_add(&events, reg_sock->fd,
	274	LPOLLIN \| LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	275	if (ret < 0) {
	276	goto error;
	277	}
	278
	279	while (1) {
	280	DBG3("[jul-thread] Manage JUL polling on %d fds",
	281	LTTNG_POLL_GETNB(&events));
	282
	283	/* Inifinite blocking call, waiting for transmission */
	284	restart:
	285	ret = lttng_poll_wait(&events, -1);
	286	if (ret < 0) {
	287	/*
	288	* Restart interrupted system call.
	289	*/
	290	if (errno == EINTR) {
	291	goto restart;
	292	}
	293	goto error;
	294	}
	295	nb_fd = ret;
f20baf8e	296	DBG3("[jul-thread] %d fd ready", nb_fd);
4d076222 DG	297
	298	for (i = 0; i < nb_fd; i++) {
	299	/* Fetch once the poll data */
	300	revents = LTTNG_POLL_GETEV(&events, i);
	301	pollfd = LTTNG_POLL_GETFD(&events, i);
	302
	303	/* Thread quit pipe has been closed. Killing thread. */
	304	ret = sessiond_check_thread_quit_pipe(pollfd, revents);
	305	if (ret) {
	306	goto exit;
	307	}
	308
	309	/*
	310	* Check first if this is a POLLERR since POLLIN is also included
	311	* in an error value thus checking first.
	312	*/
	313	if (revents & (LPOLLERR \| LPOLLHUP \| LPOLLRDHUP)) {
	314	/* Removing from the poll set */
	315	ret = lttng_poll_del(&events, pollfd);
	316	if (ret < 0) {
	317	goto error;
	318	}
	319
4d076222	320	/*
f20baf8e DG	321	* FIXME: Should we try to invalidate the JUL socket in the
f20baf8e DG	322	* associated ust app.
4d076222	323	*/
f20baf8e DG	324	destroy_jul_app(pollfd);
	325	} else if (revents & (LPOLLIN)) {
	326	int new_fd;
	327
	328	/* Pollin event of JUL app socket should NEVER happen. */
	329	assert(pollfd == reg_sock->fd);
	330
	331	new_fd = handle_registration(reg_sock);
	332	if (new_fd < 0) {
	333	WARN("[jul-thread] JUL registration failed. Ignoring.");
	334	/* Somehow the communication failed. Just continue. */
	335	continue;
	336	}
	337
	338	/* Only add poll error event to only detect shutdown. */
	339	ret = lttng_poll_add(&events, new_fd,
	340	LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	341	if (ret < 0) {
	342	destroy_jul_app(new_fd);
	343	continue;
	344	}
	345
	346	/* Update newly registered app. */
	347	update_jul_app(new_fd);
4d076222 DG	348	} else {
	349	ERR("Unknown poll events %u for sock %d", revents, pollfd);
	350	continue;
	351	}
	352	}
	353	}
	354
	355	exit:
f20baf8e DG	356	/* Whatever happens, try to delete it and exit. */
f20baf8e DG	357	(void) lttng_poll_del(&events, reg_sock->fd);
4d076222 DG	358	error:
	359	destroy_tcp_socket(reg_sock);
	360	error_tcp_socket:
	361	lttng_poll_clean(&events);
	362	error_poll_create:
	363	DBG("[jul-thread] is cleaning up and stopping.");
	364
f20baf8e DG	365	if (jul_apps_ht_by_sock) {
	366	clean_jul_apps_ht();
	367	lttng_ht_destroy(jul_apps_ht_by_sock);
	368	}
	369
4d076222 DG	370	rcu_thread_offline();
	371	rcu_unregister_thread();
	372	return NULL;
	373	}