2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 * 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License, version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include <common/futex.h>
24 #include <common/macros.h>
28 #include "testpoint.h"
30 #include "health-sessiond.h"
31 #include "lttng-sessiond.h"
34 struct thread_notifiers
{
35 struct ust_cmd_queue
*ust_cmd_queue
;
36 int apps_cmd_pipe_write_fd
;
37 int apps_cmd_notify_pipe_write_fd
;
38 int dispatch_thread_exit
;
42 * For each tracing session, update newly registered apps. The session list
43 * lock MUST be acquired before calling this.
45 static void update_ust_app(int app_sock
)
47 struct ltt_session
*sess
, *stmp
;
48 const struct ltt_session_list
*session_list
= session_get_list();
50 /* Consumer is in an ERROR state. Stop any application update. */
51 if (uatomic_read(&ust_consumerd_state
) == CONSUMER_ERROR
) {
52 /* Stop the update process since the consumer is dead. */
56 /* For all tracing session(s) */
57 cds_list_for_each_entry_safe(sess
, stmp
, &session_list
->head
, list
) {
60 if (!session_get(sess
)) {
64 if (!sess
->active
|| !sess
->ust_session
) {
69 assert(app_sock
>= 0);
70 app
= ust_app_find_by_sock(app_sock
);
73 * Application can be unregistered before so
74 * this is possible hence simply stopping the
77 DBG3("UST app update failed to find app sock %d",
81 ust_app_global_update(sess
->ust_session
, app
);
91 * Sanitize the wait queue of the dispatch registration thread meaning removing
92 * invalid nodes from it. This is to avoid memory leaks for the case the UST
93 * notify socket is never received.
95 static void sanitize_wait_queue(struct ust_reg_wait_queue
*wait_queue
)
97 int ret
, nb_fd
= 0, i
;
98 unsigned int fd_added
= 0;
99 struct lttng_poll_event events
;
100 struct ust_reg_wait_node
*wait_node
= NULL
, *tmp_wait_node
;
104 lttng_poll_init(&events
);
106 /* Just skip everything for an empty queue. */
107 if (!wait_queue
->count
) {
111 ret
= lttng_poll_create(&events
, wait_queue
->count
, LTTNG_CLOEXEC
);
116 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
117 &wait_queue
->head
, head
) {
118 assert(wait_node
->app
);
119 ret
= lttng_poll_add(&events
, wait_node
->app
->sock
,
120 LPOLLHUP
| LPOLLERR
);
133 * Poll but don't block so we can quickly identify the faulty events and
134 * clean them afterwards from the wait queue.
136 ret
= lttng_poll_wait(&events
, 0);
142 for (i
= 0; i
< nb_fd
; i
++) {
144 uint32_t revents
= LTTNG_POLL_GETEV(&events
, i
);
145 int pollfd
= LTTNG_POLL_GETFD(&events
, i
);
148 /* No activity for this FD (poll implementation). */
152 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
153 &wait_queue
->head
, head
) {
154 if (pollfd
== wait_node
->app
->sock
&&
155 (revents
& (LPOLLHUP
| LPOLLERR
))) {
156 cds_list_del(&wait_node
->head
);
158 ust_app_destroy(wait_node
->app
);
161 * Silence warning of use-after-free in
162 * cds_list_for_each_entry_safe which uses
163 * __typeof__(*wait_node).
168 ERR("Unexpected poll events %u for sock %d", revents
, pollfd
);
175 DBG("Wait queue sanitized, %d node were cleaned up", nb_fd
);
179 lttng_poll_clean(&events
);
183 lttng_poll_clean(&events
);
185 ERR("Unable to sanitize wait queue");
190 * Send a socket to a thread This is called from the dispatch UST registration
191 * thread once all sockets are set for the application.
193 * The sock value can be invalid, we don't really care, the thread will handle
194 * it and make the necessary cleanup if so.
196 * On success, return 0 else a negative value being the errno message of the
199 static int send_socket_to_thread(int fd
, int sock
)
204 * It's possible that the FD is set as invalid with -1 concurrently just
205 * before calling this function being a shutdown state of the thread.
212 ret
= lttng_write(fd
, &sock
, sizeof(sock
));
213 if (ret
< sizeof(sock
)) {
214 PERROR("write apps pipe %d", fd
);
221 /* All good. Don't send back the write positive ret value. */
227 static void cleanup_ust_dispatch_thread(void *data
)
233 * Dispatch request from the registration threads to the application
234 * communication thread.
236 static void *thread_dispatch_ust_registration(void *data
)
239 struct cds_wfcq_node
*node
;
240 struct ust_command
*ust_cmd
= NULL
;
241 struct ust_reg_wait_node
*wait_node
= NULL
, *tmp_wait_node
;
242 struct ust_reg_wait_queue wait_queue
= {
245 struct thread_notifiers
*notifiers
= data
;
247 rcu_register_thread();
249 health_register(health_sessiond
, HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH
);
251 if (testpoint(sessiond_thread_app_reg_dispatch
)) {
252 goto error_testpoint
;
255 health_code_update();
257 CDS_INIT_LIST_HEAD(&wait_queue
.head
);
259 DBG("[thread] Dispatch UST command started");
262 health_code_update();
264 /* Atomically prepare the queue futex */
265 futex_nto1_prepare(¬ifiers
->ust_cmd_queue
->futex
);
267 if (CMM_LOAD_SHARED(notifiers
->dispatch_thread_exit
)) {
272 struct ust_app
*app
= NULL
;
276 * Make sure we don't have node(s) that have hung up before receiving
277 * the notify socket. This is to clean the list in order to avoid
278 * memory leaks from notify socket that are never seen.
280 sanitize_wait_queue(&wait_queue
);
282 health_code_update();
283 /* Dequeue command for registration */
284 node
= cds_wfcq_dequeue_blocking(
285 ¬ifiers
->ust_cmd_queue
->head
,
286 ¬ifiers
->ust_cmd_queue
->tail
);
288 DBG("Woken up but nothing in the UST command queue");
289 /* Continue thread execution */
293 ust_cmd
= caa_container_of(node
, struct ust_command
, node
);
295 DBG("Dispatching UST registration pid:%d ppid:%d uid:%d"
296 " gid:%d sock:%d name:%s (version %d.%d)",
297 ust_cmd
->reg_msg
.pid
, ust_cmd
->reg_msg
.ppid
,
298 ust_cmd
->reg_msg
.uid
, ust_cmd
->reg_msg
.gid
,
299 ust_cmd
->sock
, ust_cmd
->reg_msg
.name
,
300 ust_cmd
->reg_msg
.major
, ust_cmd
->reg_msg
.minor
);
302 if (ust_cmd
->reg_msg
.type
== USTCTL_SOCKET_CMD
) {
303 wait_node
= zmalloc(sizeof(*wait_node
));
305 PERROR("zmalloc wait_node dispatch");
306 ret
= close(ust_cmd
->sock
);
308 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
310 lttng_fd_put(LTTNG_FD_APPS
, 1);
314 CDS_INIT_LIST_HEAD(&wait_node
->head
);
316 /* Create application object if socket is CMD. */
317 wait_node
->app
= ust_app_create(&ust_cmd
->reg_msg
,
319 if (!wait_node
->app
) {
320 ret
= close(ust_cmd
->sock
);
322 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
324 lttng_fd_put(LTTNG_FD_APPS
, 1);
330 * Add application to the wait queue so we can set the notify
331 * socket before putting this object in the global ht.
333 cds_list_add(&wait_node
->head
, &wait_queue
.head
);
338 * We have to continue here since we don't have the notify
339 * socket and the application MUST be added to the hash table
340 * only at that moment.
345 * Look for the application in the local wait queue and set the
346 * notify socket if found.
348 cds_list_for_each_entry_safe(wait_node
, tmp_wait_node
,
349 &wait_queue
.head
, head
) {
350 health_code_update();
351 if (wait_node
->app
->pid
== ust_cmd
->reg_msg
.pid
) {
352 wait_node
->app
->notify_sock
= ust_cmd
->sock
;
353 cds_list_del(&wait_node
->head
);
355 app
= wait_node
->app
;
357 DBG3("UST app notify socket %d is set", ust_cmd
->sock
);
363 * With no application at this stage the received socket is
364 * basically useless so close it before we free the cmd data
365 * structure for good.
368 ret
= close(ust_cmd
->sock
);
370 PERROR("close ust sock dispatch %d", ust_cmd
->sock
);
372 lttng_fd_put(LTTNG_FD_APPS
, 1);
381 * Lock the global session list so from the register up to the
382 * registration done message, no thread can see the application
383 * and change its state.
389 * Add application to the global hash table. This needs to be
390 * done before the update to the UST registry can locate the
395 /* Set app version. This call will print an error if needed. */
396 (void) ust_app_version(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(health_sessiond
);
493 rcu_unregister_thread();
497 static bool shutdown_ust_dispatch_thread(void *data
)
499 struct thread_notifiers
*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(sizeof(*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
);