Fix: double RCU unlock on event_agent_disable_all
[lttng-tools.git] / src / bin / lttng-sessiond / ust-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#define _GNU_SOURCE
6c1c0768 18#define _LGPL_SOURCE
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19#include <assert.h>
20
21#include <common/common.h>
22#include <common/utils.h>
23
24#include "fd-limit.h"
25#include "lttng-sessiond.h"
26#include "ust-thread.h"
8782cc74 27#include "health-sessiond.h"
9ad42ec1 28#include "testpoint.h"
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29
30/*
31 * This thread manage application notify communication.
32 */
33void *ust_thread_manage_notify(void *data)
34{
380e8d6f 35 int i, ret, pollfd, err = -1;
6cd525e8 36 ssize_t size_ret;
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37 uint32_t revents, nb_fd;
38 struct lttng_poll_event events;
39
40 DBG("[ust-thread] Manage application notify command");
41
42 rcu_register_thread();
43 rcu_thread_online();
44
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45 health_register(health_sessiond,
46 HEALTH_SESSIOND_TYPE_APP_MANAGE_NOTIFY);
380e8d6f 47
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48 if (testpoint(sessiond_thread_app_manage_notify)) {
49 goto error_testpoint;
50 }
51
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52 health_code_update();
53
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54 ret = sessiond_set_thread_pollset(&events, 2);
55 if (ret < 0) {
56 goto error_poll_create;
57 }
58
59 /* Add notify pipe to the pollset. */
60 ret = lttng_poll_add(&events, apps_cmd_notify_pipe[0], LPOLLIN | LPOLLERR);
61 if (ret < 0) {
62 goto error;
63 }
64
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65 health_code_update();
66
d0b96690 67 while (1) {
7fa2082e 68 DBG3("[ust-thread] Manage notify polling");
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69
70 /* Inifinite blocking call, waiting for transmission */
71restart:
380e8d6f 72 health_poll_entry();
d0b96690 73 ret = lttng_poll_wait(&events, -1);
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74 DBG3("[ust-thread] Manage notify return from poll on %d fds",
75 LTTNG_POLL_GETNB(&events));
380e8d6f 76 health_poll_exit();
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77 if (ret < 0) {
78 /*
79 * Restart interrupted system call.
80 */
81 if (errno == EINTR) {
82 goto restart;
83 }
84 goto error;
85 }
86
87 nb_fd = ret;
88
89 for (i = 0; i < nb_fd; i++) {
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90 health_code_update();
91
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92 /* Fetch once the poll data */
93 revents = LTTNG_POLL_GETEV(&events, i);
94 pollfd = LTTNG_POLL_GETFD(&events, i);
95
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96 if (!revents) {
97 /* No activity for this FD (poll implementation). */
98 continue;
99 }
100
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101 /* Thread quit pipe has been closed. Killing thread. */
102 ret = sessiond_check_thread_quit_pipe(pollfd, revents);
103 if (ret) {
380e8d6f 104 err = 0;
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105 goto exit;
106 }
107
108 /* Inspect the apps cmd pipe */
109 if (pollfd == apps_cmd_notify_pipe[0]) {
110 int sock;
111
112 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
113 ERR("Apps notify command pipe error");
114 goto error;
115 } else if (!(revents & LPOLLIN)) {
116 /* No POLLIN and not a catched error, stop the thread. */
117 ERR("Notify command pipe failed. revent: %u", revents);
118 goto error;
119 }
120
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121 /* Get socket from dispatch thread. */
122 size_ret = lttng_read(apps_cmd_notify_pipe[0],
123 &sock, sizeof(sock));
124 if (size_ret < sizeof(sock)) {
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125 PERROR("read apps notify pipe");
126 goto error;
127 }
380e8d6f 128 health_code_update();
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129
130 ret = lttng_poll_add(&events, sock,
131 LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
132 if (ret < 0) {
133 /*
134 * It's possible we've reached the max poll fd allowed.
135 * Let's close the socket but continue normal execution.
136 */
137 ret = close(sock);
138 if (ret) {
139 PERROR("close notify socket %d", sock);
140 }
141 lttng_fd_put(LTTNG_FD_APPS, 1);
142 continue;
143 }
144 DBG3("UST thread notify added sock %d to pollset", sock);
145 } else {
146 /*
147 * At this point, we know that a registered application
148 * triggered the event.
149 */
150 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
151 /* Removing from the poll set */
152 ret = lttng_poll_del(&events, pollfd);
153 if (ret < 0) {
154 goto error;
155 }
156
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157 /* The socket is closed after a grace period here. */
158 ust_app_notify_sock_unregister(pollfd);
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159 } else if (revents & (LPOLLIN | LPOLLPRI)) {
160 ret = ust_app_recv_notify(pollfd);
161 if (ret < 0) {
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162 /*
163 * If the notification failed either the application is
164 * dead or an internal error happened. In both cases,
165 * we can only continue here. If the application is
166 * dead, an unregistration will follow or else the
167 * application will notice that we are not responding
168 * on that socket and will close it.
169 */
170 continue;
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171 }
172 } else {
173 ERR("Unknown poll events %u for sock %d", revents, pollfd);
174 continue;
175 }
380e8d6f 176 health_code_update();
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177 }
178 }
179 }
180
181exit:
182error:
183 lttng_poll_clean(&events);
184error_poll_create:
9ad42ec1 185error_testpoint:
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186 utils_close_pipe(apps_cmd_notify_pipe);
187 apps_cmd_notify_pipe[0] = apps_cmd_notify_pipe[1] = -1;
188 DBG("Application notify communication apps thread cleanup complete");
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189 if (err) {
190 health_error();
191 ERR("Health error occurred in %s", __func__);
192 }
8782cc74 193 health_unregister(health_sessiond);
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194 rcu_thread_offline();
195 rcu_unregister_thread();
196 return NULL;
197}
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