consumerd: send a buffer static sample on flush command
[lttng-tools.git] / src / bin / lttng-sessiond / agent-thread.cpp
CommitLineData
4d076222 1/*
ab5be9fa 2 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
4d076222 3 *
ab5be9fa 4 * SPDX-License-Identifier: GPL-2.0-only
4d076222 5 *
4d076222
DG
6 */
7
6c1c0768 8#define _LGPL_SOURCE
4d076222 9
c9e313bc
SM
10#include <common/common.hpp>
11#include <common/sessiond-comm/sessiond-comm.hpp>
12#include <common/uri.hpp>
13#include <common/utils.hpp>
14
15#include <common/compat/endian.hpp>
16
17#include "fd-limit.hpp"
18#include "agent-thread.hpp"
19#include "agent.hpp"
20#include "lttng-sessiond.hpp"
21#include "session.hpp"
22#include "utils.hpp"
23#include "thread.hpp"
4d076222 24
f1494934 25namespace {
c78d8e86
JG
26struct thread_notifiers {
27 struct lttng_pipe *quit_pipe;
28 sem_t ready;
29};
30
733c9165
JG
31struct agent_app_id {
32 pid_t pid;
33 enum lttng_domain_type domain;
34};
35
36struct agent_protocol_version {
37 unsigned int major, minor;
38};
39
f1494934 40int agent_tracing_enabled = -1;
f28f9e44 41
4d076222
DG
42/*
43 * Note that there is not port here. It's set after this URI is parsed so we
44 * can let the user define a custom one. However, localhost is ALWAYS the
45 * default listening address.
46 */
f1494934
JG
47const char *default_reg_uri = "tcp://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS;
48} /* namespace */
4d076222 49
f20baf8e 50/*
022d91ba 51 * Update agent application using the given socket. This is done just after
f20baf8e
DG
52 * registration was successful.
53 *
733c9165
JG
54 * This will acquire the various sessions' lock; none must be held by the
55 * caller.
56 * The caller must hold the session list lock.
f20baf8e 57 */
733c9165 58static void update_agent_app(const struct agent_app *app)
f20baf8e
DG
59{
60 struct ltt_session *session, *stmp;
61 struct ltt_session_list *list;
44760c20
JR
62 struct agent *trigger_agent;
63 struct lttng_ht_iter iter;
f20baf8e
DG
64
65 list = session_get_list();
a0377dfe 66 LTTNG_ASSERT(list);
f20baf8e 67
f20baf8e 68 cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
e32d7f27
JG
69 if (!session_get(session)) {
70 continue;
71 }
72
f20baf8e
DG
73 session_lock(session);
74 if (session->ust_session) {
733c9165 75 const struct agent *agt;
fefd409b 76
4da703ad 77 rcu_read_lock();
fefd409b
DG
78 agt = trace_ust_find_agent(session->ust_session, app->domain);
79 if (agt) {
733c9165 80 agent_update(agt, app);
fefd409b 81 }
4da703ad 82 rcu_read_unlock();
f20baf8e
DG
83 }
84 session_unlock(session);
e32d7f27 85 session_put(session);
f20baf8e 86 }
44760c20
JR
87
88 rcu_read_lock();
89 /*
90 * We are protected against the addition of new events by the session
91 * list lock being held.
92 */
412d7227
SM
93 cds_lfht_for_each_entry(the_trigger_agents_ht_by_domain->ht,
94 &iter.iter, trigger_agent, node.node) {
44760c20
JR
95 agent_update(trigger_agent, app);
96 }
97 rcu_read_unlock();
f20baf8e
DG
98}
99
4d076222
DG
100/*
101 * Create and init socket from uri.
102 */
103static struct lttcomm_sock *init_tcp_socket(void)
104{
105 int ret;
106 struct lttng_uri *uri = NULL;
107 struct lttcomm_sock *sock = NULL;
2288467f
JG
108 unsigned int port;
109 bool bind_succeeded = false;
4d076222
DG
110
111 /*
112 * This should never fail since the URI is hardcoded and the port is set
113 * before this thread is launched.
114 */
115 ret = uri_parse(default_reg_uri, &uri);
a0377dfe
FD
116 LTTNG_ASSERT(ret);
117 LTTNG_ASSERT(the_config.agent_tcp_port.begin > 0);
412d7227 118 uri->port = the_config.agent_tcp_port.begin;
4d076222
DG
119
120 sock = lttcomm_alloc_sock_from_uri(uri);
121 uri_free(uri);
122 if (sock == NULL) {
bd0514a5 123 ERR("agent allocating TCP socket");
4d076222
DG
124 goto error;
125 }
126
127 ret = lttcomm_create_sock(sock);
128 if (ret < 0) {
129 goto error;
130 }
131
412d7227
SM
132 for (port = the_config.agent_tcp_port.begin;
133 port <= the_config.agent_tcp_port.end; port++) {
2288467f
JG
134 ret = lttcomm_sock_set_port(sock, (uint16_t) port);
135 if (ret) {
bd0514a5 136 ERR("Failed to set port %u on socket",
2288467f
JG
137 port);
138 goto error;
139 }
bd0514a5 140 DBG3("Trying to bind on port %u", port);
2288467f
JG
141 ret = sock->ops->bind(sock);
142 if (!ret) {
143 bind_succeeded = true;
144 break;
145 }
146
147 if (errno == EADDRINUSE) {
148 DBG("Failed to bind to port %u since it is already in use",
149 port);
150 } else {
151 PERROR("Failed to bind to port %u", port);
152 goto error;
153 }
154 }
155
156 if (!bind_succeeded) {
412d7227
SM
157 if (the_config.agent_tcp_port.begin ==
158 the_config.agent_tcp_port.end) {
2288467f 159 WARN("Another process is already using the agent port %i. "
412d7227
SM
160 "Agent support will be deactivated.",
161 the_config.agent_tcp_port.begin);
2288467f
JG
162 goto error;
163 } else {
164 WARN("All ports in the range [%i, %i] are already in use. "
412d7227
SM
165 "Agent support will be deactivated.",
166 the_config.agent_tcp_port.begin,
167 the_config.agent_tcp_port.end);
2288467f
JG
168 goto error;
169 }
4d076222
DG
170 }
171
172 ret = sock->ops->listen(sock, -1);
173 if (ret < 0) {
174 goto error;
175 }
176
bd0514a5 177 DBG("Listening on TCP port %u and socket %d",
2288467f 178 port, sock->fd);
4d076222
DG
179
180 return sock;
181
182error:
183 if (sock) {
184 lttcomm_destroy_sock(sock);
185 }
186 return NULL;
187}
188
189/*
190 * Close and destroy the given TCP socket.
191 */
192static void destroy_tcp_socket(struct lttcomm_sock *sock)
193{
2288467f
JG
194 int ret;
195 uint16_t port;
196
a0377dfe 197 LTTNG_ASSERT(sock);
4d076222 198
2288467f
JG
199 ret = lttcomm_sock_get_port(sock, &port);
200 if (ret) {
bd0514a5 201 ERR("Failed to get port of agent TCP socket");
2288467f
JG
202 port = 0;
203 }
204
bd0514a5 205 DBG3("Destroy TCP socket on port %" PRIu16,
2288467f 206 port);
4d076222
DG
207
208 /* This will return gracefully if fd is invalid. */
209 sock->ops->close(sock);
210 lttcomm_destroy_sock(sock);
211}
212
733c9165
JG
213static const char *domain_type_str(enum lttng_domain_type domain_type)
214{
215 switch (domain_type) {
216 case LTTNG_DOMAIN_NONE:
217 return "none";
218 case LTTNG_DOMAIN_KERNEL:
219 return "kernel";
220 case LTTNG_DOMAIN_UST:
221 return "ust";
222 case LTTNG_DOMAIN_JUL:
223 return "jul";
224 case LTTNG_DOMAIN_LOG4J:
225 return "log4j";
226 case LTTNG_DOMAIN_PYTHON:
227 return "python";
228 default:
229 return "unknown";
230 }
231}
232
233static bool is_agent_protocol_version_supported(
234 const struct agent_protocol_version *version)
235{
236 const bool is_supported = version->major == AGENT_MAJOR_VERSION &&
237 version->minor == AGENT_MINOR_VERSION;
238
239 if (!is_supported) {
240 WARN("Refusing agent connection: unsupported protocol version %ui.%ui, expected %i.%i",
241 version->major, version->minor,
242 AGENT_MAJOR_VERSION, AGENT_MINOR_VERSION);
243 }
244
245 return is_supported;
246}
247
f20baf8e 248/*
733c9165 249 * Handle a new agent connection on the registration socket.
f20baf8e 250 *
733c9165
JG
251 * Returns 0 on success, or else a negative errno value.
252 * On success, the resulting socket is returned through `agent_app_socket`
253 * and the application's reported id is updated through `agent_app_id`.
f20baf8e 254 */
733c9165
JG
255static int accept_agent_connection(
256 struct lttcomm_sock *reg_sock,
257 struct agent_app_id *agent_app_id,
258 struct lttcomm_sock **agent_app_socket)
f20baf8e
DG
259{
260 int ret;
733c9165 261 struct agent_protocol_version agent_version;
f20baf8e 262 ssize_t size;
022d91ba 263 struct agent_register_msg msg;
f20baf8e
DG
264 struct lttcomm_sock *new_sock;
265
a0377dfe 266 LTTNG_ASSERT(reg_sock);
f20baf8e
DG
267
268 new_sock = reg_sock->ops->accept(reg_sock);
269 if (!new_sock) {
270 ret = -ENOTCONN;
733c9165 271 goto end;
f20baf8e
DG
272 }
273
274 size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
275 if (size < sizeof(msg)) {
733c9165
JG
276 if (size < 0) {
277 PERROR("Failed to register new agent application");
278 } else if (size != 0) {
279 ERR("Failed to register new agent application: invalid registration message length: expected length = %zu, message length = %zd",
280 sizeof(msg), size);
281 } else {
282 DBG("Failed to register new agent application: connection closed");
283 }
79865500 284 ret = -EINVAL;
733c9165 285 goto error_close_socket;
9474416f 286 }
f20baf8e 287
733c9165
JG
288 agent_version = (struct agent_protocol_version) {
289 be32toh(msg.major_version),
290 be32toh(msg.minor_version),
291 };
f20baf8e 292
733c9165
JG
293 /* Test communication protocol version of the registering agent. */
294 if (!is_agent_protocol_version_supported(&agent_version)) {
295 ret = -EINVAL;
296 goto error_close_socket;
f20baf8e
DG
297 }
298
733c9165 299 *agent_app_id = (struct agent_app_id) {
733c9165 300 .pid = (pid_t) be32toh(msg.pid),
7966af57 301 .domain = (lttng_domain_type) be32toh(msg.domain),
733c9165 302 };
f20baf8e 303
733c9165
JG
304 DBG2("New registration for agent application: pid = %ld, domain = %s, socket fd = %d",
305 (long) agent_app_id->pid,
306 domain_type_str(agent_app_id->domain), new_sock->fd);
1b500e7a 307
733c9165
JG
308 *agent_app_socket = new_sock;
309 new_sock = NULL;
310 ret = 0;
311 goto end;
f20baf8e 312
733c9165 313error_close_socket:
f20baf8e
DG
314 new_sock->ops->close(new_sock);
315 lttcomm_destroy_sock(new_sock);
733c9165 316end:
f20baf8e
DG
317 return ret;
318}
319
f28f9e44
JG
320bool agent_tracing_is_enabled(void)
321{
322 int enabled;
323
324 enabled = uatomic_read(&agent_tracing_enabled);
a0377dfe 325 LTTNG_ASSERT(enabled != -1);
f28f9e44
JG
326 return enabled == 1;
327}
328
2288467f
JG
329/*
330 * Write agent TCP port using the rundir.
331 */
332static int write_agent_port(uint16_t port)
333{
412d7227
SM
334 return utils_create_pid_file(
335 (pid_t) port, the_config.agent_port_file_path.value);
2288467f
JG
336}
337
c78d8e86
JG
338static
339void mark_thread_as_ready(struct thread_notifiers *notifiers)
340{
341 DBG("Marking agent management thread as ready");
342 sem_post(&notifiers->ready);
343}
344
345static
346void wait_until_thread_is_ready(struct thread_notifiers *notifiers)
347{
348 DBG("Waiting for agent management thread to be ready");
349 sem_wait(&notifiers->ready);
350 DBG("Agent management thread is ready");
351}
352
4d076222
DG
353/*
354 * This thread manage application notify communication.
355 */
8a7e4590 356static void *thread_agent_management(void *data)
4d076222
DG
357{
358 int i, ret, pollfd;
359 uint32_t revents, nb_fd;
360 struct lttng_poll_event events;
361 struct lttcomm_sock *reg_sock;
7966af57 362 struct thread_notifiers *notifiers = (thread_notifiers *) data;
c78d8e86
JG
363 const int quit_pipe_read_fd = lttng_pipe_get_readfd(
364 notifiers->quit_pipe);
4d076222 365
bd0514a5 366 DBG("Manage agent application registration.");
4d076222
DG
367
368 rcu_register_thread();
369 rcu_thread_online();
370
022d91ba 371 /* Agent initialization call MUST be called before starting the thread. */
a0377dfe 372 LTTNG_ASSERT(the_agent_apps_ht_by_sock);
f20baf8e 373
8a7e4590
JG
374 /* Create pollset with size 2, quit pipe and registration socket. */
375 ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
4d076222
DG
376 if (ret < 0) {
377 goto error_poll_create;
378 }
379
8a7e4590
JG
380 ret = lttng_poll_add(&events, quit_pipe_read_fd,
381 LPOLLIN | LPOLLERR);
382 if (ret < 0) {
383 goto error_tcp_socket;
384 }
385
4d076222 386 reg_sock = init_tcp_socket();
2288467f
JG
387 if (reg_sock) {
388 uint16_t port;
389
cc3b9644 390 ret = lttcomm_sock_get_port(reg_sock, &port);
a0377dfe 391 LTTNG_ASSERT(ret == 0);
2288467f
JG
392
393 ret = write_agent_port(port);
394 if (ret) {
bd0514a5 395 ERR("Failed to create agent port file: agent tracing will be unavailable");
2288467f 396 /* Don't prevent the launch of the sessiond on error. */
c78d8e86 397 mark_thread_as_ready(notifiers);
2288467f
JG
398 goto error;
399 }
400 } else {
401 /* Don't prevent the launch of the sessiond on error. */
c78d8e86 402 mark_thread_as_ready(notifiers);
2288467f
JG
403 goto error_tcp_socket;
404 }
f28f9e44
JG
405
406 /*
407 * Signal that the agent thread is ready. The command thread
408 * may start to query whether or not agent tracing is enabled.
409 */
2288467f 410 uatomic_set(&agent_tracing_enabled, 1);
c78d8e86 411 mark_thread_as_ready(notifiers);
4d076222 412
733c9165 413 /* Add TCP socket to the poll set. */
4d076222
DG
414 ret = lttng_poll_add(&events, reg_sock->fd,
415 LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
416 if (ret < 0) {
417 goto error;
418 }
419
420 while (1) {
bd0514a5 421 DBG3("Manage agent polling");
4d076222
DG
422
423 /* Inifinite blocking call, waiting for transmission */
424restart:
425 ret = lttng_poll_wait(&events, -1);
bd0514a5 426 DBG3("Manage agent return from poll on %d fds",
7fa2082e 427 LTTNG_POLL_GETNB(&events));
4d076222
DG
428 if (ret < 0) {
429 /*
430 * Restart interrupted system call.
431 */
432 if (errno == EINTR) {
433 goto restart;
434 }
435 goto error;
436 }
437 nb_fd = ret;
bd0514a5 438 DBG3("%d fd ready", nb_fd);
4d076222
DG
439
440 for (i = 0; i < nb_fd; i++) {
441 /* Fetch once the poll data */
442 revents = LTTNG_POLL_GETEV(&events, i);
443 pollfd = LTTNG_POLL_GETFD(&events, i);
444
445 /* Thread quit pipe has been closed. Killing thread. */
8a7e4590 446 if (pollfd == quit_pipe_read_fd) {
4d076222
DG
447 goto exit;
448 }
449
733c9165 450 /* Activity on the registration socket. */
03e43155 451 if (revents & LPOLLIN) {
733c9165
JG
452 struct agent_app_id new_app_id;
453 struct agent_app *new_app = NULL;
454 struct lttcomm_sock *new_app_socket;
455 int new_app_socket_fd;
f20baf8e 456
a0377dfe 457 LTTNG_ASSERT(pollfd == reg_sock->fd);
733c9165
JG
458
459 ret = accept_agent_connection(
460 reg_sock, &new_app_id, &new_app_socket);
461 if (ret < 0) {
462 /* Errors are already logged. */
f20baf8e
DG
463 continue;
464 }
465
03e43155 466 /*
733c9165
JG
467 * new_app_socket's ownership has been
468 * transferred to the new agent app.
03e43155 469 */
733c9165
JG
470 new_app = agent_create_app(new_app_id.pid,
471 new_app_id.domain,
472 new_app_socket);
473 if (!new_app) {
474 new_app_socket->ops->close(
475 new_app_socket);
476 continue;
477 }
478 new_app_socket_fd = new_app_socket->fd;
479 new_app_socket = NULL;
480
481 /*
482 * Since this is a command socket (write then
483 * read), only add poll error event to only
484 * detect shutdown.
485 */
486 ret = lttng_poll_add(&events, new_app_socket_fd,
f20baf8e
DG
487 LPOLLERR | LPOLLHUP | LPOLLRDHUP);
488 if (ret < 0) {
733c9165 489 agent_destroy_app(new_app);
f20baf8e
DG
490 continue;
491 }
492
733c9165
JG
493 /*
494 * Prevent sessions from being modified while
495 * the agent application's configuration is
496 * updated.
497 */
498 session_lock_list();
499
500 /*
501 * Update the newly registered applications's
502 * configuration.
503 */
504 update_agent_app(new_app);
1b500e7a 505
733c9165 506 ret = agent_send_registration_done(new_app);
03e43155 507 if (ret < 0) {
733c9165
JG
508 agent_destroy_app(new_app);
509 /* Removing from the poll set. */
510 ret = lttng_poll_del(&events,
511 new_app_socket_fd);
03e43155 512 if (ret < 0) {
733c9165 513 session_unlock_list();
03e43155
MD
514 goto error;
515 }
03e43155
MD
516 continue;
517 }
733c9165
JG
518
519 /* Publish the new agent app. */
520 agent_add_app(new_app);
521
522 session_unlock_list();
03e43155
MD
523 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
524 /* Removing from the poll set */
525 ret = lttng_poll_del(&events, pollfd);
526 if (ret < 0) {
527 goto error;
528 }
529 agent_destroy_app_by_sock(pollfd);
4d076222 530 } else {
03e43155
MD
531 ERR("Unexpected poll events %u for sock %d", revents, pollfd);
532 goto error;
4d076222
DG
533 }
534 }
535 }
536
537exit:
f20baf8e
DG
538 /* Whatever happens, try to delete it and exit. */
539 (void) lttng_poll_del(&events, reg_sock->fd);
4d076222
DG
540error:
541 destroy_tcp_socket(reg_sock);
542error_tcp_socket:
543 lttng_poll_clean(&events);
544error_poll_create:
2288467f 545 uatomic_set(&agent_tracing_enabled, 0);
bd0514a5 546 DBG("Cleaning up and stopping.");
4d076222
DG
547 rcu_thread_offline();
548 rcu_unregister_thread();
549 return NULL;
550}
8a7e4590
JG
551
552static bool shutdown_agent_management_thread(void *data)
553{
7966af57 554 struct thread_notifiers *notifiers = (thread_notifiers *) data;
c78d8e86 555 const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe);
8a7e4590
JG
556
557 return notify_thread_pipe(write_fd) == 1;
558}
559
5b093681
JG
560static void cleanup_agent_management_thread(void *data)
561{
7966af57 562 struct thread_notifiers *notifiers = (thread_notifiers *) data;
5b093681 563
c78d8e86
JG
564 lttng_pipe_destroy(notifiers->quit_pipe);
565 sem_destroy(&notifiers->ready);
566 free(notifiers);
5b093681
JG
567}
568
569bool launch_agent_management_thread(void)
8a7e4590 570{
c78d8e86 571 struct thread_notifiers *notifiers;
8a7e4590
JG
572 struct lttng_thread *thread;
573
64803277 574 notifiers = zmalloc<thread_notifiers>();
c78d8e86 575 if (!notifiers) {
21fa020e 576 goto error_alloc;
c78d8e86
JG
577 }
578
579 sem_init(&notifiers->ready, 0, 0);
580 notifiers->quit_pipe = lttng_pipe_open(FD_CLOEXEC);
581 if (!notifiers->quit_pipe) {
8a7e4590
JG
582 goto error;
583 }
584 thread = lttng_thread_create("Agent management",
585 thread_agent_management,
586 shutdown_agent_management_thread,
5b093681 587 cleanup_agent_management_thread,
c78d8e86 588 notifiers);
8a7e4590
JG
589 if (!thread) {
590 goto error;
591 }
c78d8e86 592 wait_until_thread_is_ready(notifiers);
8a7e4590
JG
593 lttng_thread_put(thread);
594 return true;
595error:
c78d8e86 596 cleanup_agent_management_thread(notifiers);
21fa020e 597error_alloc:
8a7e4590
JG
598 return false;
599}
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