Test fix: use temp file sync. of test app
[lttng-tools.git] / src / bin / lttng-sessiond / jul-thread.c
CommitLineData
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1/*
2 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
3 *
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.
7 *
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
11 * more details.
12 *
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.
16 */
17
18#define _GNU_SOURCE
19#include <assert.h>
20
21#include <common/common.h>
22#include <common/sessiond-comm/sessiond-comm.h>
23#include <common/uri.h>
24#include <common/utils.h>
25
26#include "fd-limit.h"
27#include "jul-thread.h"
28#include "lttng-sessiond.h"
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29#include "session.h"
30#include "utils.h"
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31
32/*
33 * Note that there is not port here. It's set after this URI is parsed so we
34 * can let the user define a custom one. However, localhost is ALWAYS the
35 * default listening address.
36 */
37static const char *default_reg_uri = "tcp://localhost";
38
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39/*
40 * Update JUL application using the given socket. This is done just after
41 * registration was successful.
42 *
43 * This is a quite heavy call in terms of locking since the session list lock
44 * AND session lock are acquired.
45 */
46static void update_jul_app(int sock)
47{
48 struct ltt_session *session, *stmp;
49 struct ltt_session_list *list;
50
51 list = session_get_list();
52 assert(list);
53
54 session_lock_list();
55 cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
56 session_lock(session);
57 if (session->ust_session) {
58 jul_update(&session->ust_session->domain_jul, sock);
59 }
60 session_unlock(session);
61 }
62 session_unlock_list();
63}
64
65/*
66 * Destroy a JUL application by socket.
67 */
68static void destroy_jul_app(int sock)
69{
70 struct jul_app *app;
71
72 assert(sock >= 0);
73
74 /*
75 * Not finding an application is a very important error that should NEVER
76 * happen. The hash table deletion is ONLY done through this call even on
77 * thread cleanup.
78 */
79 rcu_read_lock();
80 app = jul_find_app_by_sock(sock);
81 assert(app);
82 rcu_read_unlock();
83
84 /* RCU read side lock is taken in this function call. */
85 jul_delete_app(app);
86
87 /* The application is freed in a RCU call but the socket is closed here. */
88 jul_destroy_app(app);
89}
90
91/*
92 * Cleanup remaining JUL apps in the hash table. This should only be called in
93 * the exit path of the thread.
94 */
95static void clean_jul_apps_ht(void)
96{
97 struct lttng_ht_node_ulong *node;
98 struct lttng_ht_iter iter;
99
100 DBG3("[jul-thread] Cleaning JUL apps ht");
101
102 rcu_read_lock();
103 cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, node, node) {
104 struct jul_app *app;
105
106 app = caa_container_of(node, struct jul_app, node);
107 destroy_jul_app(app->sock->fd);
108 }
109 rcu_read_unlock();
110}
111
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112/*
113 * Create and init socket from uri.
114 */
115static struct lttcomm_sock *init_tcp_socket(void)
116{
117 int ret;
118 struct lttng_uri *uri = NULL;
119 struct lttcomm_sock *sock = NULL;
120
121 /*
122 * This should never fail since the URI is hardcoded and the port is set
123 * before this thread is launched.
124 */
125 ret = uri_parse(default_reg_uri, &uri);
126 assert(ret);
127 assert(jul_tcp_port);
128 uri->port = jul_tcp_port;
129
130 sock = lttcomm_alloc_sock_from_uri(uri);
131 uri_free(uri);
132 if (sock == NULL) {
133 ERR("[jul-thread] JUL allocating TCP socket");
134 goto error;
135 }
136
137 ret = lttcomm_create_sock(sock);
138 if (ret < 0) {
139 goto error;
140 }
141
142 ret = sock->ops->bind(sock);
143 if (ret < 0) {
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144 WARN("An other session daemon is using this JUL port. JUL support "
145 "will be deactivated not interfering with the tracing.");
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146 goto error;
147 }
148
149 ret = sock->ops->listen(sock, -1);
150 if (ret < 0) {
151 goto error;
152 }
153
154 DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
155 sock->fd);
156
157 return sock;
158
159error:
160 if (sock) {
161 lttcomm_destroy_sock(sock);
162 }
163 return NULL;
164}
165
166/*
167 * Close and destroy the given TCP socket.
168 */
169static void destroy_tcp_socket(struct lttcomm_sock *sock)
170{
171 assert(sock);
172
173 DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);
174
175 /* This will return gracefully if fd is invalid. */
176 sock->ops->close(sock);
177 lttcomm_destroy_sock(sock);
178}
179
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180/*
181 * Handle a new JUL registration using the reg socket. After that, a new JUL
182 * application is added to the global hash table and attach to an UST app
183 * object.
184 *
185 * Return the new FD created upon accept() on success or else a negative errno
186 * value.
187 */
188static int handle_registration(struct lttcomm_sock *reg_sock)
189{
190 int ret;
191 pid_t pid;
192 ssize_t size;
193 struct jul_app *app;
194 struct jul_register_msg msg;
195 struct lttcomm_sock *new_sock;
196
197 assert(reg_sock);
198
199 new_sock = reg_sock->ops->accept(reg_sock);
200 if (!new_sock) {
201 ret = -ENOTCONN;
202 goto error;
203 }
204
205 size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
206 if (size < sizeof(msg)) {
207 ret = -errno;
208 goto error_socket;
209 }
210 pid = be32toh(msg.pid);
211
212 DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
213 new_sock->fd);
214
215 app = jul_create_app(pid, new_sock);
216 if (!app) {
217 ret = -ENOMEM;
218 goto error_socket;
219 }
220
221 /*
222 * Add before assigning the socket value to the UST app so it can be found
223 * concurrently.
224 */
225 jul_add_app(app);
226
227 /*
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228 * We don't need to attach the JUL app to the app. If we ever do
229 * so, we should consider both registration order of JUL before
230 * app and app before JUL.
f20baf8e 231 */
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232
233 return new_sock->fd;
234
235error_socket:
236 new_sock->ops->close(new_sock);
237 lttcomm_destroy_sock(new_sock);
238error:
239 return ret;
240}
241
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242/*
243 * This thread manage application notify communication.
244 */
245void *jul_thread_manage_registration(void *data)
246{
247 int i, ret, pollfd;
248 uint32_t revents, nb_fd;
249 struct lttng_poll_event events;
250 struct lttcomm_sock *reg_sock;
251
252 DBG("[jul-thread] Manage JUL application registration.");
253
254 rcu_register_thread();
255 rcu_thread_online();
256
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257 /* JUL initialization call MUST be called before starting the thread. */
258 assert(jul_apps_ht_by_sock);
259
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260 /* Create pollset with size 2, quit pipe and socket. */
261 ret = sessiond_set_thread_pollset(&events, 2);
262 if (ret < 0) {
263 goto error_poll_create;
264 }
265
266 reg_sock = init_tcp_socket();
267 if (!reg_sock) {
268 goto error_tcp_socket;
269 }
270
271 /* Add create valid TCP socket to poll set. */
272 ret = lttng_poll_add(&events, reg_sock->fd,
273 LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
274 if (ret < 0) {
275 goto error;
276 }
277
278 while (1) {
279 DBG3("[jul-thread] Manage JUL polling on %d fds",
280 LTTNG_POLL_GETNB(&events));
281
282 /* Inifinite blocking call, waiting for transmission */
283restart:
284 ret = lttng_poll_wait(&events, -1);
285 if (ret < 0) {
286 /*
287 * Restart interrupted system call.
288 */
289 if (errno == EINTR) {
290 goto restart;
291 }
292 goto error;
293 }
294 nb_fd = ret;
f20baf8e 295 DBG3("[jul-thread] %d fd ready", nb_fd);
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296
297 for (i = 0; i < nb_fd; i++) {
298 /* Fetch once the poll data */
299 revents = LTTNG_POLL_GETEV(&events, i);
300 pollfd = LTTNG_POLL_GETFD(&events, i);
301
302 /* Thread quit pipe has been closed. Killing thread. */
303 ret = sessiond_check_thread_quit_pipe(pollfd, revents);
304 if (ret) {
305 goto exit;
306 }
307
308 /*
309 * Check first if this is a POLLERR since POLLIN is also included
310 * in an error value thus checking first.
311 */
312 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
313 /* Removing from the poll set */
314 ret = lttng_poll_del(&events, pollfd);
315 if (ret < 0) {
316 goto error;
317 }
318
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319 destroy_jul_app(pollfd);
320 } else if (revents & (LPOLLIN)) {
321 int new_fd;
322
323 /* Pollin event of JUL app socket should NEVER happen. */
324 assert(pollfd == reg_sock->fd);
325
326 new_fd = handle_registration(reg_sock);
327 if (new_fd < 0) {
328 WARN("[jul-thread] JUL registration failed. Ignoring.");
329 /* Somehow the communication failed. Just continue. */
330 continue;
331 }
332
333 /* Only add poll error event to only detect shutdown. */
334 ret = lttng_poll_add(&events, new_fd,
335 LPOLLERR | LPOLLHUP | LPOLLRDHUP);
336 if (ret < 0) {
337 destroy_jul_app(new_fd);
338 continue;
339 }
340
341 /* Update newly registered app. */
342 update_jul_app(new_fd);
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343 } else {
344 ERR("Unknown poll events %u for sock %d", revents, pollfd);
345 continue;
346 }
347 }
348 }
349
350exit:
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351 /* Whatever happens, try to delete it and exit. */
352 (void) lttng_poll_del(&events, reg_sock->fd);
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353error:
354 destroy_tcp_socket(reg_sock);
355error_tcp_socket:
356 lttng_poll_clean(&events);
357error_poll_create:
358 DBG("[jul-thread] is cleaning up and stopping.");
359
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360 if (jul_apps_ht_by_sock) {
361 clean_jul_apps_ht();
362 lttng_ht_destroy(jul_apps_ht_by_sock);
363 }
364
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365 rcu_thread_offline();
366 rcu_unregister_thread();
367 return NULL;
368}
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