4 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
5 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; only
10 * version 2.1 of the License.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include <sys/types.h>
23 #include <sys/socket.h>
26 #include <ust/lttng-ust-abi.h>
27 #include <lttng-ust-comm.h>
28 #include <ust/usterr-signal-safe.h>
30 #include <semaphore.h>
33 #include <urcu/uatomic.h>
36 * communication thread mutex. Held when handling a command, also held
37 * by fork() to deal with removal of threads, and by exit path.
39 static pthread_mutex_t lttng_ust_comm_mutex
= PTHREAD_MUTEX_INITIALIZER
;
41 /* Should the ust comm thread quit ? */
42 static int lttng_ust_comm_should_quit
;
45 * Wait for either of these before continuing to the main
47 * - the register_done message from sessiond daemon
48 * (will let the sessiond daemon enable sessions before main
50 * - sessiond daemon is not reachable.
51 * - timeout (ensuring applications are resilient to session
54 static sem_t constructor_wait
;
55 static int sem_count
= { 2 };
58 * Info about socket and associated listener thread.
62 char sock_path
[PATH_MAX
];
64 pthread_t ust_listener
; /* listener thread */
68 /* Socket from app (connect) to session daemon (listen) for communication */
69 struct sock_info global_apps
= {
71 .sock_path
= DEFAULT_GLOBAL_APPS_UNIX_SOCK
,
76 /* TODO: allow global_apps_sock_path override */
78 struct sock_info local_apps
= {
85 int setup_local_apps_socket(void)
89 home_dir
= (const char *) getenv("HOME");
92 snprintf(local_apps
.sock_path
, PATH_MAX
,
93 DEFAULT_HOME_APPS_UNIX_SOCK
, home_dir
);
98 int register_app_to_sessiond(int socket
)
108 reg_msg
.major
= LTTNG_UST_COMM_VERSION_MAJOR
;
109 reg_msg
.minor
= LTTNG_UST_COMM_VERSION_MINOR
;
110 reg_msg
.pid
= getpid();
111 reg_msg
.uid
= getuid();
113 ret
= lttcomm_send_unix_sock(socket
, ®_msg
, sizeof(reg_msg
));
114 if (ret
>= 0 && ret
!= sizeof(reg_msg
))
120 int send_reply(int sock
, struct lttcomm_ust_reply
*lur
)
124 len
= lttcomm_send_unix_sock(sock
, lur
, sizeof(*lur
));
127 DBG("message successfully sent");
130 if (errno
== ECONNRESET
) {
131 printf("remote end closed connection\n");
136 printf("incorrect message size: %zd\n", len
);
142 int handle_register_done(void)
146 ret
= uatomic_add_return(&sem_count
, -1);
148 ret
= sem_post(&constructor_wait
);
155 int handle_message(struct sock_info
*sock_info
,
156 int sock
, struct lttcomm_ust_msg
*lum
)
159 const struct objd_ops
*ops
;
160 struct lttcomm_ust_reply lur
;
162 pthread_mutex_lock(<tng_ust_comm_mutex
);
164 memset(&lur
, 0, sizeof(lur
));
166 if (lttng_ust_comm_should_quit
) {
171 ops
= objd_ops(lum
->handle
);
178 case LTTNG_UST_REGISTER_DONE
:
179 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
180 ret
= handle_register_done();
184 case LTTNG_UST_RELEASE
:
185 if (lum
->handle
== LTTNG_UST_ROOT_HANDLE
)
188 ret
= objd_unref(lum
->handle
);
192 ret
= ops
->cmd(lum
->handle
, lum
->cmd
,
193 (unsigned long) &lum
->u
);
200 lur
.handle
= lum
->handle
;
204 lur
.ret_code
= LTTCOMM_OK
;
206 lur
.ret_code
= LTTCOMM_SESSION_FAIL
;
208 ret
= send_reply(sock
, &lur
);
210 pthread_mutex_unlock(<tng_ust_comm_mutex
);
215 void cleanup_sock_info(struct sock_info
*sock_info
)
219 if (sock_info
->socket
!= -1) {
220 ret
= close(sock_info
->socket
);
222 ERR("Error closing local apps socket");
224 sock_info
->socket
= -1;
226 if (sock_info
->root_handle
!= -1) {
227 ret
= objd_unref(sock_info
->root_handle
);
229 ERR("Error unref root handle");
231 sock_info
->root_handle
= -1;
236 * This thread does not allocate any resource, except within
237 * handle_message, within mutex protection. This mutex protects against
239 * The other moment it allocates resources is at socket connexion, which
240 * is also protected by the mutex.
243 void *ust_listener_thread(void *arg
)
245 struct sock_info
*sock_info
= arg
;
248 /* Restart trying to connect to the session daemon */
250 pthread_mutex_lock(<tng_ust_comm_mutex
);
252 if (lttng_ust_comm_should_quit
) {
253 pthread_mutex_unlock(<tng_ust_comm_mutex
);
257 if (sock_info
->socket
!= -1) {
258 ret
= close(sock_info
->socket
);
260 ERR("Error closing %s apps socket", sock_info
->name
);
262 sock_info
->socket
= -1;
265 /* Check for sessiond availability with pipe TODO */
268 ret
= lttcomm_connect_unix_sock(sock_info
->sock_path
);
270 ERR("Error connecting to %s apps socket", sock_info
->name
);
272 * If we cannot find the sessiond daemon, don't delay
273 * constructor execution.
275 ret
= handle_register_done();
277 pthread_mutex_unlock(<tng_ust_comm_mutex
);
282 sock_info
->socket
= sock
= ret
;
285 * Create only one root handle per listener thread for the whole
288 if (sock_info
->root_handle
== -1) {
289 ret
= lttng_abi_create_root_handle();
291 ERR("Error creating root handle");
292 pthread_mutex_unlock(<tng_ust_comm_mutex
);
295 sock_info
->root_handle
= ret
;
298 ret
= register_app_to_sessiond(sock
);
300 ERR("Error registering to %s apps socket", sock_info
->name
);
302 * If we cannot register to the sessiond daemon, don't
303 * delay constructor execution.
305 ret
= handle_register_done();
307 pthread_mutex_unlock(<tng_ust_comm_mutex
);
311 pthread_mutex_unlock(<tng_ust_comm_mutex
);
315 struct lttcomm_ust_msg lum
;
317 len
= lttcomm_recv_unix_sock(sock
, &lum
, sizeof(lum
));
319 case 0: /* orderly shutdown */
320 DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info
->name
);
323 DBG("message received\n");
324 ret
= handle_message(sock_info
, sock
, &lum
);
326 ERR("Error handling message for %s socket", sock_info
->name
);
330 if (errno
== ECONNRESET
) {
331 ERR("%s remote end closed connection\n", sock_info
->name
);
336 ERR("incorrect message size (%s socket): %zd\n", sock_info
->name
, len
);
342 goto restart
; /* try to reconnect */
348 * Return values: -1: don't wait. 0: wait forever. 1: timeout wait.
351 int get_timeout(struct timespec
*constructor_timeout
)
353 long constructor_delay_ms
= LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS
;
357 str_delay
= getenv("UST_REGISTER_TIMEOUT");
359 constructor_delay_ms
= strtol(str_delay
, NULL
, 10);
362 switch (constructor_delay_ms
) {
363 case -1:/* fall-through */
365 return constructor_delay_ms
;
371 * If we are unable to find the current time, don't wait.
373 ret
= clock_gettime(CLOCK_REALTIME
, constructor_timeout
);
377 constructor_timeout
->tv_sec
+= constructor_delay_ms
/ 1000UL;
378 constructor_timeout
->tv_nsec
+=
379 (constructor_delay_ms
% 1000UL) * 1000000UL;
380 if (constructor_timeout
->tv_nsec
>= 1000000000UL) {
381 constructor_timeout
->tv_sec
++;
382 constructor_timeout
->tv_nsec
-= 1000000000UL;
388 * sessiond monitoring thread: monitor presence of global and per-user
389 * sessiond by polling the application common named pipe.
393 void __attribute__((constructor
)) lttng_ust_comm_init(void)
395 struct timespec constructor_timeout
;
401 timeout_mode
= get_timeout(&constructor_timeout
);
403 ret
= sem_init(&constructor_wait
, 0, 0);
406 ret
= setup_local_apps_socket();
408 ERR("Error setting up to local apps socket");
411 ret
= pthread_create(&global_apps
.ust_listener
, NULL
,
412 ust_listener_thread
, &global_apps
);
413 ret
= pthread_create(&local_apps
.ust_listener
, NULL
,
414 ust_listener_thread
, &local_apps
);
416 switch (timeout_mode
) {
417 case 1: /* timeout wait */
419 ret
= sem_timedwait(&constructor_wait
,
420 &constructor_timeout
);
421 } while (ret
< 0 && errno
== EINTR
);
422 if (ret
< 0 && errno
== ETIMEDOUT
) {
423 ERR("Timed out waiting for ltt-sessiond");
428 case -1:/* wait forever */
430 ret
= sem_wait(&constructor_wait
);
431 } while (ret
< 0 && errno
== EINTR
);
434 case 0: /* no timeout */
439 void __attribute__((destructor
)) lttng_ust_comm_exit(void)
444 * Using pthread_cancel here because:
445 * A) we don't want to hang application teardown.
446 * B) the thread is not allocating any resource.
450 * Require the communication thread to quit. Synchronize with
451 * mutexes to ensure it is not in a mutex critical section when
452 * pthread_cancel is later called.
454 pthread_mutex_lock(<tng_ust_comm_mutex
);
455 lttng_ust_comm_should_quit
= 1;
456 pthread_mutex_unlock(<tng_ust_comm_mutex
);
459 ret
= pthread_cancel(global_apps
.ust_listener
);
461 ERR("Error cancelling global ust listener thread");
465 cleanup_sock_info(&global_apps
);
467 ret
= pthread_cancel(local_apps
.ust_listener
);
469 ERR("Error cancelling local ust listener thread");
472 cleanup_sock_info(&local_apps
);
474 lttng_ust_abi_exit();