[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://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS;

/*
 * 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("Another session daemon is using this JUL port. JUL support "
				"will be deactivated to prevent 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. If r_app is not NULL, the created app is set to the pointer.
 *
 * Return the new FD created upon accept() on success or else a negative errno
 * value.
 */
static int handle_registration(struct lttcomm_sock *reg_sock,
		struct jul_app **r_app)
{
	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.
	 */

	if (r_app) {
		*r_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;
				}

				destroy_jul_app(pollfd);
			} else if (revents & (LPOLLIN)) {
				int new_fd;
				struct jul_app *app = NULL;

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

				new_fd = handle_registration(reg_sock, &app);
				if (new_fd < 0) {
					WARN("[jul-thread] JUL registration failed. Ignoring.");
					/* Somehow the communication failed. Just continue. */
					continue;
				}
				/* Should not have a NULL app on success. */
				assert(app);

				/* 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);

				/* On failure, the poll will detect it and clean it up. */
				(void) jul_send_registration_done(app);
			} 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	*/
fa91dc52 MD	37	static const char *default_reg_uri =
fa91dc52 MD	38	"tcp://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS;
4d076222	39
f20baf8e DG	40	/*
	41	* Update JUL application using the given socket. This is done just after
	42	* registration was successful.
	43	*
	44	* This is a quite heavy call in terms of locking since the session list lock
	45	* AND session lock are acquired.
	46	*/
	47	static void update_jul_app(int sock)
	48	{
	49	struct ltt_session session, stmp;
	50	struct ltt_session_list *list;
	51
	52	list = session_get_list();
	53	assert(list);
	54
	55	session_lock_list();
	56	cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
	57	session_lock(session);
	58	if (session->ust_session) {
	59	jul_update(&session->ust_session->domain_jul, sock);
	60	}
	61	session_unlock(session);
	62	}
	63	session_unlock_list();
	64	}
	65
	66	/*
	67	* Destroy a JUL application by socket.
	68	*/
	69	static void destroy_jul_app(int sock)
	70	{
	71	struct jul_app *app;
	72
	73	assert(sock >= 0);
	74
	75	/*
	76	* Not finding an application is a very important error that should NEVER
	77	* happen. The hash table deletion is ONLY done through this call even on
	78	* thread cleanup.
	79	*/
	80	rcu_read_lock();
	81	app = jul_find_app_by_sock(sock);
	82	assert(app);
	83	rcu_read_unlock();
	84
	85	/* RCU read side lock is taken in this function call. */
	86	jul_delete_app(app);
	87
	88	/* The application is freed in a RCU call but the socket is closed here. */
	89	jul_destroy_app(app);
	90	}
	91
	92	/*
	93	* Cleanup remaining JUL apps in the hash table. This should only be called in
	94	* the exit path of the thread.
	95	*/
	96	static void clean_jul_apps_ht(void)
	97	{
	98	struct lttng_ht_node_ulong *node;
	99	struct lttng_ht_iter iter;
	100
	101	DBG3("[jul-thread] Cleaning JUL apps ht");
	102
	103	rcu_read_lock();
104	cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, node, node) {
105	struct jul_app *app;
106
107	app = caa_container_of(node, struct jul_app, node);
108	destroy_jul_app(app->sock->fd);
109	}
110	rcu_read_unlock();
111	}
112
4d076222 DG	113	/*
	114	* Create and init socket from uri.
	115	*/
	116	static struct lttcomm_sock *init_tcp_socket(void)
	117	{
	118	int ret;
	119	struct lttng_uri *uri = NULL;
	120	struct lttcomm_sock *sock = NULL;
	121
	122	/*
	123	* This should never fail since the URI is hardcoded and the port is set
	124	* before this thread is launched.
	125	*/
	126	ret = uri_parse(default_reg_uri, &uri);
	127	assert(ret);
	128	assert(jul_tcp_port);
	129	uri->port = jul_tcp_port;
	130
	131	sock = lttcomm_alloc_sock_from_uri(uri);
	132	uri_free(uri);
	133	if (sock == NULL) {
	134	ERR("[jul-thread] JUL allocating TCP socket");
	135	goto error;
	136	}
	137
	138	ret = lttcomm_create_sock(sock);
	139	if (ret < 0) {
	140	goto error;
	141	}
	142
	143	ret = sock->ops->bind(sock);
	144	if (ret < 0) {
5368d366 MJ	145	WARN("Another session daemon is using this JUL port. JUL support "
5368d366 MJ	146	"will be deactivated to prevent interfering with the tracing.");
4d076222 DG	147	goto error;
	148	}
	149
	150	ret = sock->ops->listen(sock, -1);
	151	if (ret < 0) {
	152	goto error;
	153	}
	154
	155	DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
	156	sock->fd);
	157
	158	return sock;
	159
	160	error:
	161	if (sock) {
	162	lttcomm_destroy_sock(sock);
	163	}
	164	return NULL;
	165	}
	166
	167	/*
	168	* Close and destroy the given TCP socket.
	169	*/
	170	static void destroy_tcp_socket(struct lttcomm_sock *sock)
	171	{
	172	assert(sock);
	173
	174	DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);
	175
	176	/* This will return gracefully if fd is invalid. */
	177	sock->ops->close(sock);
	178	lttcomm_destroy_sock(sock);
	179	}
	180
f20baf8e DG	181	/*
	182	* Handle a new JUL registration using the reg socket. After that, a new JUL
	183	* application is added to the global hash table and attach to an UST app
1b500e7a	184	* object. If r_app is not NULL, the created app is set to the pointer.
f20baf8e DG	185	*
	186	* Return the new FD created upon accept() on success or else a negative errno
	187	* value.
	188	*/
1b500e7a DG	189	static int handle_registration(struct lttcomm_sock *reg_sock,
1b500e7a DG	190	struct jul_app **r_app)
f20baf8e DG	191	{
	192	int ret;
	193	pid_t pid;
	194	ssize_t size;
	195	struct jul_app *app;
	196	struct jul_register_msg msg;
	197	struct lttcomm_sock *new_sock;
	198
	199	assert(reg_sock);
	200
	201	new_sock = reg_sock->ops->accept(reg_sock);
	202	if (!new_sock) {
	203	ret = -ENOTCONN;
	204	goto error;
	205	}
	206
	207	size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
	208	if (size < sizeof(msg)) {
	209	ret = -errno;
	210	goto error_socket;
	211	}
	212	pid = be32toh(msg.pid);
	213
	214	DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
	215	new_sock->fd);
	216
	217	app = jul_create_app(pid, new_sock);
	218	if (!app) {
	219	ret = -ENOMEM;
	220	goto error_socket;
	221	}
	222
	223	/*
	224	* Add before assigning the socket value to the UST app so it can be found
	225	* concurrently.
	226	*/
	227	jul_add_app(app);
	228
	229	/*
6c509840 MD	230	* We don't need to attach the JUL app to the app. If we ever do
	231	* so, we should consider both registration order of JUL before
	232	* app and app before JUL.
f20baf8e	233	*/
f20baf8e	234
1b500e7a DG	235	if (r_app) {
	236	*r_app = app;
	237	}
	238
f20baf8e DG	239	return new_sock->fd;
	240
	241	error_socket:
	242	new_sock->ops->close(new_sock);
	243	lttcomm_destroy_sock(new_sock);
	244	error:
	245	return ret;
	246	}
	247
4d076222 DG	248	/*
	249	* This thread manage application notify communication.
	250	*/
	251	void jul_thread_manage_registration(void data)
	252	{
	253	int i, ret, pollfd;
	254	uint32_t revents, nb_fd;
	255	struct lttng_poll_event events;
	256	struct lttcomm_sock *reg_sock;
	257
	258	DBG("[jul-thread] Manage JUL application registration.");
	259
	260	rcu_register_thread();
	261	rcu_thread_online();
	262
f20baf8e DG	263	/* JUL initialization call MUST be called before starting the thread. */
	264	assert(jul_apps_ht_by_sock);
	265
4d076222 DG	266	/* Create pollset with size 2, quit pipe and socket. */
	267	ret = sessiond_set_thread_pollset(&events, 2);
	268	if (ret < 0) {
	269	goto error_poll_create;
	270	}
	271
	272	reg_sock = init_tcp_socket();
	273	if (!reg_sock) {
	274	goto error_tcp_socket;
	275	}
	276
	277	/* Add create valid TCP socket to poll set. */
	278	ret = lttng_poll_add(&events, reg_sock->fd,
	279	LPOLLIN \| LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	280	if (ret < 0) {
	281	goto error;
	282	}
	283
	284	while (1) {
	285	DBG3("[jul-thread] Manage JUL polling on %d fds",
	286	LTTNG_POLL_GETNB(&events));
	287
	288	/* Inifinite blocking call, waiting for transmission */
	289	restart:
	290	ret = lttng_poll_wait(&events, -1);
	291	if (ret < 0) {
	292	/*
	293	* Restart interrupted system call.
	294	*/
	295	if (errno == EINTR) {
	296	goto restart;
	297	}
	298	goto error;
	299	}
	300	nb_fd = ret;
f20baf8e	301	DBG3("[jul-thread] %d fd ready", nb_fd);
4d076222 DG	302
	303	for (i = 0; i < nb_fd; i++) {
	304	/* Fetch once the poll data */
	305	revents = LTTNG_POLL_GETEV(&events, i);
	306	pollfd = LTTNG_POLL_GETFD(&events, i);
	307
	308	/* Thread quit pipe has been closed. Killing thread. */
	309	ret = sessiond_check_thread_quit_pipe(pollfd, revents);
	310	if (ret) {
	311	goto exit;
	312	}
	313
	314	/*
	315	* Check first if this is a POLLERR since POLLIN is also included
	316	* in an error value thus checking first.
	317	*/
	318	if (revents & (LPOLLERR \| LPOLLHUP \| LPOLLRDHUP)) {
	319	/* Removing from the poll set */
	320	ret = lttng_poll_del(&events, pollfd);
	321	if (ret < 0) {
	322	goto error;
	323	}
	324
f20baf8e DG	325	destroy_jul_app(pollfd);
	326	} else if (revents & (LPOLLIN)) {
	327	int new_fd;
1b500e7a	328	struct jul_app *app = NULL;
f20baf8e DG	329
	330	/* Pollin event of JUL app socket should NEVER happen. */
	331	assert(pollfd == reg_sock->fd);
	332
1b500e7a	333	new_fd = handle_registration(reg_sock, &app);
f20baf8e DG	334	if (new_fd < 0) {
	335	WARN("[jul-thread] JUL registration failed. Ignoring.");
	336	/* Somehow the communication failed. Just continue. */
	337	continue;
	338	}
1b500e7a DG	339	/* Should not have a NULL app on success. */
1b500e7a DG	340	assert(app);
f20baf8e DG	341
	342	/* Only add poll error event to only detect shutdown. */
	343	ret = lttng_poll_add(&events, new_fd,
	344	LPOLLERR \| LPOLLHUP \| LPOLLRDHUP);
	345	if (ret < 0) {
	346	destroy_jul_app(new_fd);
	347	continue;
	348	}
	349
	350	/* Update newly registered app. */
	351	update_jul_app(new_fd);
1b500e7a DG	352
	353	/* On failure, the poll will detect it and clean it up. */
	354	(void) jul_send_registration_done(app);
4d076222 DG	355	} else {
	356	ERR("Unknown poll events %u for sock %d", revents, pollfd);
	357	continue;
	358	}
	359	}
	360	}
	361
	362	exit:
f20baf8e DG	363	/* Whatever happens, try to delete it and exit. */
f20baf8e DG	364	(void) lttng_poll_del(&events, reg_sock->fd);
4d076222 DG	365	error:
	366	destroy_tcp_socket(reg_sock);
	367	error_tcp_socket:
	368	lttng_poll_clean(&events);
	369	error_poll_create:
	370	DBG("[jul-thread] is cleaning up and stopping.");
	371
f20baf8e DG	372	if (jul_apps_ht_by_sock) {
	373	clean_jul_apps_ht();
	374	lttng_ht_destroy(jul_apps_ht_by_sock);
	375	}
	376
4d076222 DG	377	rcu_thread_offline();
	378	rcu_unregister_thread();
	379	return NULL;
	380	}