2 * Copyright (C) 2011 EfficiOS Inc.
3 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
6 * SPDX-License-Identifier: GPL-2.0-only
13 #include <common/futex.hpp>
14 #include <common/macros.hpp>
16 #include "dispatch.hpp"
17 #include "ust-app.hpp"
18 #include "testpoint.hpp"
19 #include "fd-limit.hpp"
20 #include "health-sessiond.hpp"
21 #include "lttng-sessiond.hpp"
24 struct thread_notifiers
{
25 struct ust_cmd_queue
*ust_cmd_queue
;
26 int apps_cmd_pipe_write_fd
;
27 int apps_cmd_notify_pipe_write_fd
;
28 int dispatch_thread_exit
;
32 * For each tracing session, update newly registered apps. The session list
33 * lock MUST be acquired before calling this.
35 static void update_ust_app(int app_sock
)
37 struct ltt_session
*sess
, *stmp
;
38 const struct ltt_session_list
*session_list
= session_get_list();
41 /* Consumer is in an ERROR state. Stop any application update. */
42 if (uatomic_read(&the_ust_consumerd_state
) == CONSUMER_ERROR
) {
43 /* Stop the update process since the consumer is dead. */
48 LTTNG_ASSERT(app_sock
>= 0);
49 app
= ust_app_find_by_sock(app_sock
);
52 * Application can be unregistered before so
53 * this is possible hence simply stopping the
56 DBG3("UST app update failed to find app sock %d",
61 /* Update all event notifiers for the app. */
62 ust_app_global_update_event_notifier_rules(app
);
64 /* For all tracing session(s) */
65 cds_list_for_each_entry_safe(sess
, stmp
, &session_list
->head
, list
) {
66 if (!session_get(sess
)) {
70 if (!sess
->active
|| !sess
->ust_session
||
71 !sess
->ust_session
->active
) {
75 ust_app_global_update(sess
->ust_session
, app
);
86 * Sanitize the wait queue of the dispatch registration thread meaning removing
87 * invalid nodes from it. This is to avoid memory leaks for the case the UST
88 * notify socket is never received.
90 static void sanitize_wait_queue(struct ust_reg_wait_queue
*wait_queue
)
92 int ret
, nb_fd
= 0, i
;
93 unsigned int fd_added
= 0;
94 struct lttng_poll_event events
;
95 struct ust_reg_wait_node
*wait_node
= NULL
, *tmp_wait_node
;
97 LTTNG_ASSERT(wait_queue
);
99 lttng_poll_init(&events
);
101 /* Just skip everything for an empty queue. */
102 if (!wait_queue
->count
) {
106 ret
= lttng_poll_create(&events
, wait_queue
->count
, LTTNG_CLOEXEC
);
111 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
112 &wait_queue
->head
, head
) {
113 LTTNG_ASSERT(wait_node
->app
);
114 ret
= lttng_poll_add(&events
, wait_node
->app
->sock
,
115 LPOLLHUP
| LPOLLERR
);
128 * Poll but don't block so we can quickly identify the faulty events and
129 * clean them afterwards from the wait queue.
131 ret
= lttng_poll_wait(&events
, 0);
137 for (i
= 0; i
< nb_fd
; i
++) {
139 uint32_t revents
= LTTNG_POLL_GETEV(&events
, i
);
140 int pollfd
= LTTNG_POLL_GETFD(&events
, i
);
142 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
143 &wait_queue
->head
, head
) {
144 if (pollfd
== wait_node
->app
->sock
&&
145 (revents
& (LPOLLHUP
| LPOLLERR
))) {
146 cds_list_del(&wait_node
->head
);
148 ust_app_destroy(wait_node
->app
);
151 * Silence warning of use-after-free in
152 * cds_list_for_each_entry_safe which uses
153 * __typeof__(*wait_node).
158 ERR("Unexpected poll events %u for sock %d", revents
, pollfd
);
165 DBG("Wait queue sanitized, %d node were cleaned up", nb_fd
);
169 lttng_poll_clean(&events
);
173 lttng_poll_clean(&events
);
175 ERR("Unable to sanitize wait queue");
180 * Send a socket to a thread This is called from the dispatch UST registration
181 * thread once all sockets are set for the application.
183 * The sock value can be invalid, we don't really care, the thread will handle
184 * it and make the necessary cleanup if so.
186 * On success, return 0 else a negative value being the errno message of the
189 static int send_socket_to_thread(int fd
, int sock
)
194 * It's possible that the FD is set as invalid with -1 concurrently just
195 * before calling this function being a shutdown state of the thread.
202 ret
= lttng_write(fd
, &sock
, sizeof(sock
));
203 if (ret
< sizeof(sock
)) {
204 PERROR("write apps pipe %d", fd
);
211 /* All good. Don't send back the write positive ret value. */
217 static void cleanup_ust_dispatch_thread(void *data
)
223 * Dispatch request from the registration threads to the application
224 * communication thread.
226 static void *thread_dispatch_ust_registration(void *data
)
229 struct cds_wfcq_node
*node
;
230 struct ust_command
*ust_cmd
= NULL
;
231 struct ust_reg_wait_node
*wait_node
= NULL
, *tmp_wait_node
;
232 struct ust_reg_wait_queue wait_queue
= {
236 struct thread_notifiers
*notifiers
= (thread_notifiers
*) data
;
238 rcu_register_thread();
240 health_register(the_health_sessiond
,
241 HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH
);
243 if (testpoint(sessiond_thread_app_reg_dispatch
)) {
244 goto error_testpoint
;
247 health_code_update();
249 CDS_INIT_LIST_HEAD(&wait_queue
.head
);
251 DBG("[thread] Dispatch UST command started");
254 health_code_update();
256 /* Atomically prepare the queue futex */
257 futex_nto1_prepare(¬ifiers
->ust_cmd_queue
->futex
);
259 if (CMM_LOAD_SHARED(notifiers
->dispatch_thread_exit
)) {
264 struct ust_app
*app
= NULL
;
268 * Make sure we don't have node(s) that have hung up before receiving
269 * the notify socket. This is to clean the list in order to avoid
270 * memory leaks from notify socket that are never seen.
272 sanitize_wait_queue(&wait_queue
);
274 health_code_update();
275 /* Dequeue command for registration */
276 node
= cds_wfcq_dequeue_blocking(
277 ¬ifiers
->ust_cmd_queue
->head
,
278 ¬ifiers
->ust_cmd_queue
->tail
);
280 DBG("Woken up but nothing in the UST command queue");
281 /* Continue thread execution */
285 ust_cmd
= caa_container_of(node
, struct ust_command
, node
);
287 DBG("Dispatching UST registration pid:%d ppid:%d uid:%d"
288 " gid:%d sock:%d name:%s (version %d.%d)",
289 ust_cmd
->reg_msg
.pid
, ust_cmd
->reg_msg
.ppid
,
290 ust_cmd
->reg_msg
.uid
, ust_cmd
->reg_msg
.gid
,
291 ust_cmd
->sock
, ust_cmd
->reg_msg
.name
,
292 ust_cmd
->reg_msg
.major
, ust_cmd
->reg_msg
.minor
);
294 if (ust_cmd
->reg_msg
.type
== LTTNG_UST_CTL_SOCKET_CMD
) {
295 wait_node
= zmalloc
<ust_reg_wait_node
>();
297 PERROR("zmalloc wait_node dispatch");
298 ret
= close(ust_cmd
->sock
);
300 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
302 lttng_fd_put(LTTNG_FD_APPS
, 1);
307 CDS_INIT_LIST_HEAD(&wait_node
->head
);
309 /* Create application object if socket is CMD. */
310 wait_node
->app
= ust_app_create(&ust_cmd
->reg_msg
,
312 if (!wait_node
->app
) {
313 ret
= close(ust_cmd
->sock
);
315 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
317 lttng_fd_put(LTTNG_FD_APPS
, 1);
325 * Add application to the wait queue so we can set the notify
326 * socket before putting this object in the global ht.
328 cds_list_add(&wait_node
->head
, &wait_queue
.head
);
334 * We have to continue here since we don't have the notify
335 * socket and the application MUST be added to the hash table
336 * only at that moment.
341 * Look for the application in the local wait queue and set the
342 * notify socket if found.
344 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
345 &wait_queue
.head
, head
) {
346 health_code_update();
347 if (wait_node
->app
->pid
== ust_cmd
->reg_msg
.pid
) {
348 wait_node
->app
->notify_sock
= ust_cmd
->sock
;
349 cds_list_del(&wait_node
->head
);
351 app
= wait_node
->app
;
354 DBG3("UST app notify socket %d is set", ust_cmd
->sock
);
360 * With no application at this stage the received socket is
361 * basically useless so close it before we free the cmd data
362 * structure for good.
365 ret
= close(ust_cmd
->sock
);
367 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
369 lttng_fd_put(LTTNG_FD_APPS
, 1);
379 * Lock the global session list so from the register up to the
380 * registration done message, no thread can see the application
381 * and change its state.
387 * Add application to the global hash table. This needs to be
388 * done before the update to the UST registry can locate the
393 /* Set app version. This call will print an error if needed. */
394 (void) ust_app_version(app
);
396 (void) ust_app_setup_event_notifier_group(app
);
398 /* Send notify socket through the notify pipe. */
399 ret
= send_socket_to_thread(
400 notifiers
->apps_cmd_notify_pipe_write_fd
,
404 session_unlock_list();
406 * No notify thread, stop the UST tracing. However, this is
407 * not an internal error of the this thread thus setting
408 * the health error code to a normal exit.
415 * Update newly registered application with the tracing
416 * registry info already enabled information.
418 update_ust_app(app
->sock
);
421 * Don't care about return value. Let the manage apps threads
422 * handle app unregistration upon socket close.
424 (void) ust_app_register_done(app
);
427 * Even if the application socket has been closed, send the app
428 * to the thread and unregistration will take place at that
431 ret
= send_socket_to_thread(
432 notifiers
->apps_cmd_pipe_write_fd
,
436 session_unlock_list();
438 * No apps. thread, stop the UST tracing. However, this is
439 * not an internal error of the this thread thus setting
440 * the health error code to a normal exit.
447 session_unlock_list();
449 } while (node
!= NULL
);
452 /* Futex wait on queue. Blocking call on futex() */
453 futex_nto1_wait(¬ifiers
->ust_cmd_queue
->futex
);
456 /* Normal exit, no error */
460 /* Clean up wait queue. */
461 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
462 &wait_queue
.head
, head
) {
463 cds_list_del(&wait_node
->head
);
468 /* Empty command queue. */
470 /* Dequeue command for registration */
471 node
= cds_wfcq_dequeue_blocking(
472 ¬ifiers
->ust_cmd_queue
->head
,
473 ¬ifiers
->ust_cmd_queue
->tail
);
477 ust_cmd
= caa_container_of(node
, struct ust_command
, node
);
478 ret
= close(ust_cmd
->sock
);
480 PERROR("close ust sock exit dispatch %d", ust_cmd
->sock
);
482 lttng_fd_put(LTTNG_FD_APPS
, 1);
487 DBG("Dispatch thread dying");
490 ERR("Health error occurred in %s", __func__
);
492 health_unregister(the_health_sessiond
);
493 rcu_unregister_thread();
497 static bool shutdown_ust_dispatch_thread(void *data
)
499 struct thread_notifiers
*notifiers
= (thread_notifiers
*) data
;
501 CMM_STORE_SHARED(notifiers
->dispatch_thread_exit
, 1);
502 futex_nto1_wake(¬ifiers
->ust_cmd_queue
->futex
);
506 bool launch_ust_dispatch_thread(struct ust_cmd_queue
*cmd_queue
,
507 int apps_cmd_pipe_write_fd
,
508 int apps_cmd_notify_pipe_write_fd
)
510 struct lttng_thread
*thread
;
511 struct thread_notifiers
*notifiers
;
513 notifiers
= zmalloc
<thread_notifiers
>();
517 notifiers
->ust_cmd_queue
= cmd_queue
;
518 notifiers
->apps_cmd_pipe_write_fd
= apps_cmd_pipe_write_fd
;
519 notifiers
->apps_cmd_notify_pipe_write_fd
= apps_cmd_notify_pipe_write_fd
;
521 thread
= lttng_thread_create("UST registration dispatch",
522 thread_dispatch_ust_registration
,
523 shutdown_ust_dispatch_thread
,
524 cleanup_ust_dispatch_thread
,
529 lttng_thread_put(thread
);