2 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
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.
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
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.
21 #include <common/common.h>
22 #include <common/sessiond-comm/sessiond-comm.h>
23 #include <common/uri.h>
24 #include <common/utils.h>
26 #include <common/compat/endian.h>
29 #include "agent-thread.h"
31 #include "lttng-sessiond.h"
35 static int agent_tracing_enabled
= -1;
38 * Note that there is not port here. It's set after this URI is parsed so we
39 * can let the user define a custom one. However, localhost is ALWAYS the
40 * default listening address.
42 static const char *default_reg_uri
=
43 "tcp://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS
;
46 * Update agent application using the given socket. This is done just after
47 * registration was successful.
49 * This is a quite heavy call in terms of locking since the session list lock
50 * AND session lock are acquired.
52 static void update_agent_app(struct agent_app
*app
)
54 struct ltt_session
*session
, *stmp
;
55 struct ltt_session_list
*list
;
57 list
= session_get_list();
61 cds_list_for_each_entry_safe(session
, stmp
, &list
->head
, list
) {
62 if (!session_get(session
)) {
66 session_lock(session
);
67 if (session
->ust_session
) {
71 agt
= trace_ust_find_agent(session
->ust_session
, app
->domain
);
73 agent_update(agt
, app
->sock
->fd
);
77 session_unlock(session
);
80 session_unlock_list();
84 * Create and init socket from uri.
86 static struct lttcomm_sock
*init_tcp_socket(void)
89 struct lttng_uri
*uri
= NULL
;
90 struct lttcomm_sock
*sock
= NULL
;
92 bool bind_succeeded
= false;
95 * This should never fail since the URI is hardcoded and the port is set
96 * before this thread is launched.
98 ret
= uri_parse(default_reg_uri
, &uri
);
100 assert(config
.agent_tcp_port
.begin
> 0);
101 uri
->port
= config
.agent_tcp_port
.begin
;
103 sock
= lttcomm_alloc_sock_from_uri(uri
);
106 ERR("[agent-thread] agent allocating TCP socket");
110 ret
= lttcomm_create_sock(sock
);
115 for (port
= config
.agent_tcp_port
.begin
;
116 port
<= config
.agent_tcp_port
.end
; port
++) {
117 ret
= lttcomm_sock_set_port(sock
, (uint16_t) port
);
119 ERR("[agent-thread] Failed to set port %u on socket",
123 DBG3("[agent-thread] Trying to bind on port %u", port
);
124 ret
= sock
->ops
->bind(sock
);
126 bind_succeeded
= true;
130 if (errno
== EADDRINUSE
) {
131 DBG("Failed to bind to port %u since it is already in use",
134 PERROR("Failed to bind to port %u", port
);
139 if (!bind_succeeded
) {
140 if (config
.agent_tcp_port
.begin
== config
.agent_tcp_port
.end
) {
141 WARN("Another process is already using the agent port %i. "
142 "Agent support will be deactivated.",
143 config
.agent_tcp_port
.begin
);
146 WARN("All ports in the range [%i, %i] are already in use. "
147 "Agent support will be deactivated.",
148 config
.agent_tcp_port
.begin
,
149 config
.agent_tcp_port
.end
);
154 ret
= sock
->ops
->listen(sock
, -1);
159 DBG("[agent-thread] Listening on TCP port %u and socket %d",
166 lttcomm_destroy_sock(sock
);
172 * Close and destroy the given TCP socket.
174 static void destroy_tcp_socket(struct lttcomm_sock
*sock
)
181 ret
= lttcomm_sock_get_port(sock
, &port
);
183 ERR("[agent-thread] Failed to get port of agent TCP socket");
187 DBG3("[agent-thread] Destroy TCP socket on port %" PRIu16
,
190 /* This will return gracefully if fd is invalid. */
191 sock
->ops
->close(sock
);
192 lttcomm_destroy_sock(sock
);
196 * Handle a new agent registration using the reg socket. After that, a new
197 * agent application is added to the global hash table and attach to an UST app
198 * object. If r_app is not NULL, the created app is set to the pointer.
200 * Return the new FD created upon accept() on success or else a negative errno
203 static int handle_registration(struct lttcomm_sock
*reg_sock
,
204 struct agent_app
**r_app
)
208 uint32_t major_version
, minor_version
;
210 enum lttng_domain_type domain
;
211 struct agent_app
*app
;
212 struct agent_register_msg msg
;
213 struct lttcomm_sock
*new_sock
;
217 new_sock
= reg_sock
->ops
->accept(reg_sock
);
223 size
= new_sock
->ops
->recvmsg(new_sock
, &msg
, sizeof(msg
), 0);
224 if (size
< sizeof(msg
)) {
228 domain
= be32toh(msg
.domain
);
229 pid
= be32toh(msg
.pid
);
230 major_version
= be32toh(msg
.major_version
);
231 minor_version
= be32toh(msg
.minor_version
);
233 /* Test communication protocol version of the registring agent. */
234 if (major_version
!= AGENT_MAJOR_VERSION
) {
238 if (minor_version
!= AGENT_MINOR_VERSION
) {
243 DBG2("[agent-thread] New registration for pid %d domain %d on socket %d",
244 pid
, domain
, new_sock
->fd
);
246 app
= agent_create_app(pid
, domain
, new_sock
);
253 * Add before assigning the socket value to the UST app so it can be found
259 * We don't need to attach the agent app to the app. If we ever do so, we
260 * should consider both registration order of agent before app and app
271 new_sock
->ops
->close(new_sock
);
272 lttcomm_destroy_sock(new_sock
);
277 bool agent_tracing_is_enabled(void)
281 enabled
= uatomic_read(&agent_tracing_enabled
);
282 assert(enabled
!= -1);
287 * Write agent TCP port using the rundir.
289 static int write_agent_port(uint16_t port
)
291 return utils_create_pid_file((pid_t
) port
,
292 config
.agent_port_file_path
.value
);
296 * This thread manage application notify communication.
298 void *agent_thread_manage_registration(void *data
)
301 uint32_t revents
, nb_fd
;
302 struct lttng_poll_event events
;
303 struct lttcomm_sock
*reg_sock
;
305 DBG("[agent-thread] Manage agent application registration.");
307 rcu_register_thread();
310 /* Agent initialization call MUST be called before starting the thread. */
311 assert(agent_apps_ht_by_sock
);
313 /* Create pollset with size 2, quit pipe and socket. */
314 ret
= sessiond_set_thread_pollset(&events
, 2);
316 sessiond_notify_ready();
317 goto error_poll_create
;
320 reg_sock
= init_tcp_socket();
324 assert(lttcomm_sock_get_port(reg_sock
, &port
) == 0);
326 ret
= write_agent_port(port
);
328 ERR("[agent-thread] Failed to create agent port file: agent tracing will be unavailable");
329 /* Don't prevent the launch of the sessiond on error. */
330 sessiond_notify_ready();
334 /* Don't prevent the launch of the sessiond on error. */
335 sessiond_notify_ready();
336 goto error_tcp_socket
;
340 * Signal that the agent thread is ready. The command thread
341 * may start to query whether or not agent tracing is enabled.
343 uatomic_set(&agent_tracing_enabled
, 1);
344 sessiond_notify_ready();
346 /* Add TCP socket to poll set. */
347 ret
= lttng_poll_add(&events
, reg_sock
->fd
,
348 LPOLLIN
| LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
);
354 DBG3("[agent-thread] Manage agent polling");
356 /* Inifinite blocking call, waiting for transmission */
358 ret
= lttng_poll_wait(&events
, -1);
359 DBG3("[agent-thread] Manage agent return from poll on %d fds",
360 LTTNG_POLL_GETNB(&events
));
363 * Restart interrupted system call.
365 if (errno
== EINTR
) {
371 DBG3("[agent-thread] %d fd ready", nb_fd
);
373 for (i
= 0; i
< nb_fd
; i
++) {
374 /* Fetch once the poll data */
375 revents
= LTTNG_POLL_GETEV(&events
, i
);
376 pollfd
= LTTNG_POLL_GETFD(&events
, i
);
379 /* No activity for this FD (poll implementation). */
383 /* Thread quit pipe has been closed. Killing thread. */
384 ret
= sessiond_check_thread_quit_pipe(pollfd
, revents
);
389 if (revents
& LPOLLIN
) {
391 struct agent_app
*app
= NULL
;
393 assert(pollfd
== reg_sock
->fd
);
394 new_fd
= handle_registration(reg_sock
, &app
);
398 /* Should not have a NULL app on success. */
402 * Since this is a command socket (write then read),
403 * only add poll error event to only detect shutdown.
405 ret
= lttng_poll_add(&events
, new_fd
,
406 LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
);
408 agent_destroy_app_by_sock(new_fd
);
412 /* Update newly registered app. */
413 update_agent_app(app
);
415 /* On failure, the poll will detect it and clean it up. */
416 ret
= agent_send_registration_done(app
);
418 /* Removing from the poll set */
419 ret
= lttng_poll_del(&events
, new_fd
);
423 agent_destroy_app_by_sock(new_fd
);
426 } else if (revents
& (LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
)) {
427 /* Removing from the poll set */
428 ret
= lttng_poll_del(&events
, pollfd
);
432 agent_destroy_app_by_sock(pollfd
);
434 ERR("Unexpected poll events %u for sock %d", revents
, pollfd
);
441 /* Whatever happens, try to delete it and exit. */
442 (void) lttng_poll_del(&events
, reg_sock
->fd
);
444 destroy_tcp_socket(reg_sock
);
446 lttng_poll_clean(&events
);
448 uatomic_set(&agent_tracing_enabled
, 0);
449 DBG("[agent-thread] is cleaning up and stopping.");
451 rcu_thread_offline();
452 rcu_unregister_thread();