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 session_lock(session
);
63 if (session
->ust_session
) {
67 agt
= trace_ust_find_agent(session
->ust_session
, app
->domain
);
69 agent_update(agt
, app
->sock
->fd
);
73 session_unlock(session
);
75 session_unlock_list();
79 * Create and init socket from uri.
81 static struct lttcomm_sock
*init_tcp_socket(void)
84 struct lttng_uri
*uri
= NULL
;
85 struct lttcomm_sock
*sock
= NULL
;
87 bool bind_succeeded
= false;
90 * This should never fail since the URI is hardcoded and the port is set
91 * before this thread is launched.
93 ret
= uri_parse(default_reg_uri
, &uri
);
95 assert(config
.agent_tcp_port
.begin
> 0);
96 uri
->port
= config
.agent_tcp_port
.begin
;
98 sock
= lttcomm_alloc_sock_from_uri(uri
);
101 ERR("[agent-thread] agent allocating TCP socket");
105 ret
= lttcomm_create_sock(sock
);
110 for (port
= config
.agent_tcp_port
.begin
;
111 port
<= config
.agent_tcp_port
.end
; port
++) {
112 ret
= lttcomm_sock_set_port(sock
, (uint16_t) port
);
114 ERR("[agent-thread] Failed to set port %u on socket",
118 DBG3("[agent-thread] Trying to bind on port %u", port
);
119 ret
= sock
->ops
->bind(sock
);
121 bind_succeeded
= true;
125 if (errno
== EADDRINUSE
) {
126 DBG("Failed to bind to port %u since it is already in use",
129 PERROR("Failed to bind to port %u", port
);
134 if (!bind_succeeded
) {
135 if (config
.agent_tcp_port
.begin
== config
.agent_tcp_port
.end
) {
136 WARN("Another process is already using the agent port %i. "
137 "Agent support will be deactivated.",
138 config
.agent_tcp_port
.begin
);
141 WARN("All ports in the range [%i, %i] are already in use. "
142 "Agent support will be deactivated.",
143 config
.agent_tcp_port
.begin
,
144 config
.agent_tcp_port
.end
);
149 ret
= sock
->ops
->listen(sock
, -1);
154 DBG("[agent-thread] Listening on TCP port %u and socket %d",
161 lttcomm_destroy_sock(sock
);
167 * Close and destroy the given TCP socket.
169 static void destroy_tcp_socket(struct lttcomm_sock
*sock
)
176 ret
= lttcomm_sock_get_port(sock
, &port
);
178 ERR("[agent-thread] Failed to get port of agent TCP socket");
182 DBG3("[agent-thread] Destroy TCP socket on port %" PRIu16
,
185 /* This will return gracefully if fd is invalid. */
186 sock
->ops
->close(sock
);
187 lttcomm_destroy_sock(sock
);
191 * Handle a new agent registration using the reg socket. After that, a new
192 * agent application is added to the global hash table and attach to an UST app
193 * object. If r_app is not NULL, the created app is set to the pointer.
195 * Return the new FD created upon accept() on success or else a negative errno
198 static int handle_registration(struct lttcomm_sock
*reg_sock
,
199 struct agent_app
**r_app
)
203 uint32_t major_version
, minor_version
;
205 enum lttng_domain_type domain
;
206 struct agent_app
*app
;
207 struct agent_register_msg msg
;
208 struct lttcomm_sock
*new_sock
;
212 new_sock
= reg_sock
->ops
->accept(reg_sock
);
218 size
= new_sock
->ops
->recvmsg(new_sock
, &msg
, sizeof(msg
), 0);
219 if (size
< sizeof(msg
)) {
223 domain
= be32toh(msg
.domain
);
224 pid
= be32toh(msg
.pid
);
225 major_version
= be32toh(msg
.major_version
);
226 minor_version
= be32toh(msg
.minor_version
);
228 /* Test communication protocol version of the registring agent. */
229 if (major_version
!= AGENT_MAJOR_VERSION
) {
233 if (minor_version
!= AGENT_MINOR_VERSION
) {
238 DBG2("[agent-thread] New registration for pid %d domain %d on socket %d",
239 pid
, domain
, new_sock
->fd
);
241 app
= agent_create_app(pid
, domain
, new_sock
);
248 * Add before assigning the socket value to the UST app so it can be found
254 * We don't need to attach the agent app to the app. If we ever do so, we
255 * should consider both registration order of agent before app and app
266 new_sock
->ops
->close(new_sock
);
267 lttcomm_destroy_sock(new_sock
);
272 bool agent_tracing_is_enabled(void)
276 enabled
= uatomic_read(&agent_tracing_enabled
);
277 assert(enabled
!= -1);
282 * Write agent TCP port using the rundir.
284 static int write_agent_port(uint16_t port
)
286 return utils_create_pid_file((pid_t
) port
,
287 config
.agent_port_file_path
.value
);
291 * This thread manage application notify communication.
293 void *agent_thread_manage_registration(void *data
)
296 uint32_t revents
, nb_fd
;
297 struct lttng_poll_event events
;
298 struct lttcomm_sock
*reg_sock
;
300 DBG("[agent-thread] Manage agent application registration.");
302 rcu_register_thread();
305 /* Agent initialization call MUST be called before starting the thread. */
306 assert(agent_apps_ht_by_sock
);
308 /* Create pollset with size 2, quit pipe and socket. */
309 ret
= sessiond_set_thread_pollset(&events
, 2);
311 sessiond_notify_ready();
312 goto error_poll_create
;
315 reg_sock
= init_tcp_socket();
319 assert(lttcomm_sock_get_port(reg_sock
, &port
) == 0);
321 ret
= write_agent_port(port
);
323 ERR("[agent-thread] Failed to create agent port file: agent tracing will be unavailable");
324 /* Don't prevent the launch of the sessiond on error. */
325 sessiond_notify_ready();
329 /* Don't prevent the launch of the sessiond on error. */
330 sessiond_notify_ready();
331 goto error_tcp_socket
;
335 * Signal that the agent thread is ready. The command thread
336 * may start to query whether or not agent tracing is enabled.
338 uatomic_set(&agent_tracing_enabled
, 1);
339 sessiond_notify_ready();
341 /* Add TCP socket to poll set. */
342 ret
= lttng_poll_add(&events
, reg_sock
->fd
,
343 LPOLLIN
| LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
);
349 DBG3("[agent-thread] Manage agent polling");
351 /* Inifinite blocking call, waiting for transmission */
353 ret
= lttng_poll_wait(&events
, -1);
354 DBG3("[agent-thread] Manage agent return from poll on %d fds",
355 LTTNG_POLL_GETNB(&events
));
358 * Restart interrupted system call.
360 if (errno
== EINTR
) {
366 DBG3("[agent-thread] %d fd ready", nb_fd
);
368 for (i
= 0; i
< nb_fd
; i
++) {
369 /* Fetch once the poll data */
370 revents
= LTTNG_POLL_GETEV(&events
, i
);
371 pollfd
= LTTNG_POLL_GETFD(&events
, i
);
374 /* No activity for this FD (poll implementation). */
378 /* Thread quit pipe has been closed. Killing thread. */
379 ret
= sessiond_check_thread_quit_pipe(pollfd
, revents
);
384 if (revents
& LPOLLIN
) {
386 struct agent_app
*app
= NULL
;
388 assert(pollfd
== reg_sock
->fd
);
389 new_fd
= handle_registration(reg_sock
, &app
);
393 /* Should not have a NULL app on success. */
397 * Since this is a command socket (write then read),
398 * only add poll error event to only detect shutdown.
400 ret
= lttng_poll_add(&events
, new_fd
,
401 LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
);
403 agent_destroy_app_by_sock(new_fd
);
407 /* Update newly registered app. */
408 update_agent_app(app
);
410 /* On failure, the poll will detect it and clean it up. */
411 ret
= agent_send_registration_done(app
);
413 /* Removing from the poll set */
414 ret
= lttng_poll_del(&events
, new_fd
);
418 agent_destroy_app_by_sock(new_fd
);
421 } else if (revents
& (LPOLLERR
| LPOLLHUP
| LPOLLRDHUP
)) {
422 /* Removing from the poll set */
423 ret
= lttng_poll_del(&events
, pollfd
);
427 agent_destroy_app_by_sock(pollfd
);
429 ERR("Unexpected poll events %u for sock %d", revents
, pollfd
);
436 /* Whatever happens, try to delete it and exit. */
437 (void) lttng_poll_del(&events
, reg_sock
->fd
);
439 destroy_tcp_socket(reg_sock
);
441 lttng_poll_clean(&events
);
443 uatomic_set(&agent_tracing_enabled
, 0);
444 DBG("[agent-thread] is cleaning up and stopping.");
446 rcu_thread_offline();
447 rcu_unregister_thread();