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a7333da7 JG |
1 | /* |
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> | |
5 | * | |
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. | |
9 | * | |
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. | |
14 | * | |
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. | |
18 | */ | |
19 | ||
20 | #include "lttng-sessiond.h" | |
21 | #include "utils.h" | |
22 | #include <common/utils.h> | |
99d688f2 JG |
23 | #include <pthread.h> |
24 | ||
25 | #define USEC_PER_SEC 1000000 | |
a7333da7 JG |
26 | |
27 | /* | |
28 | * Quit pipe for all threads. This permits a single cancellation point | |
29 | * for all threads when receiving an event on the pipe. | |
30 | */ | |
31 | static int thread_quit_pipe[2] = { -1, -1 }; | |
32 | ||
99d688f2 JG |
33 | /* |
34 | * Allows threads to query the state of the client thread. | |
35 | */ | |
36 | static struct client_thread_state { | |
37 | pthread_cond_t cond; | |
38 | pthread_mutex_t lock; | |
39 | bool is_running; | |
40 | } client_thread_state = { | |
41 | .cond = PTHREAD_COND_INITIALIZER, | |
42 | .lock = PTHREAD_MUTEX_INITIALIZER, | |
43 | .is_running = false | |
44 | }; | |
45 | ||
a7333da7 JG |
46 | /* |
47 | * Init thread quit pipe. | |
48 | * | |
49 | * Return -1 on error or 0 if all pipes are created. | |
50 | */ | |
51 | static int __init_thread_quit_pipe(int *a_pipe) | |
52 | { | |
53 | int ret, i; | |
54 | ||
55 | ret = pipe(a_pipe); | |
56 | if (ret < 0) { | |
57 | PERROR("thread quit pipe"); | |
58 | goto error; | |
59 | } | |
60 | ||
61 | for (i = 0; i < 2; i++) { | |
62 | ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC); | |
63 | if (ret < 0) { | |
64 | PERROR("fcntl"); | |
65 | goto error; | |
66 | } | |
67 | } | |
68 | ||
69 | error: | |
70 | return ret; | |
71 | } | |
72 | ||
73 | int sessiond_init_thread_quit_pipe(void) | |
74 | { | |
75 | return __init_thread_quit_pipe(thread_quit_pipe); | |
76 | } | |
77 | ||
78 | int sessiond_check_thread_quit_pipe(int fd, uint32_t events) | |
79 | { | |
80 | return (fd == thread_quit_pipe[0] && (events & LPOLLIN)); | |
81 | } | |
82 | ||
83 | /* | |
84 | * Wait for a notification on the quit pipe (with a timeout). | |
85 | * | |
99d688f2 JG |
86 | * A timeout value of -1U means no timeout. |
87 | * | |
a7333da7 JG |
88 | * Returns 1 if the caller should quit, 0 if the timeout was reached, and |
89 | * -1 if an error was encountered. | |
90 | */ | |
91 | int sessiond_wait_for_quit_pipe(unsigned int timeout_us) | |
92 | { | |
93 | int ret; | |
94 | fd_set read_fds; | |
95 | struct timeval timeout; | |
96 | ||
97 | FD_ZERO(&read_fds); | |
98 | FD_SET(thread_quit_pipe[0], &read_fds); | |
99 | memset(&timeout, 0, sizeof(timeout)); | |
99d688f2 JG |
100 | timeout.tv_sec = timeout_us / USEC_PER_SEC; |
101 | timeout.tv_usec = timeout_us % USEC_PER_SEC; | |
a7333da7 JG |
102 | |
103 | while (true) { | |
104 | ret = select(thread_quit_pipe[0] + 1, &read_fds, NULL, NULL, | |
99d688f2 | 105 | timeout_us != -1U ? &timeout : NULL); |
a7333da7 JG |
106 | if (ret < 0 && errno == EINTR) { |
107 | /* Retry on interrupt. */ | |
108 | continue; | |
109 | } else { | |
110 | break; | |
111 | } | |
112 | } | |
113 | ||
114 | if (ret > 0) { | |
115 | /* Should quit. */ | |
116 | ret = 1; | |
117 | } else if (ret < 0 && errno != EINTR) { | |
118 | /* Unknown error. */ | |
119 | PERROR("Failed to select() thread quit pipe"); | |
120 | ret = -1; | |
121 | } else { | |
122 | /* Timeout reached. */ | |
123 | ret = 0; | |
124 | } | |
125 | ||
126 | return ret; | |
127 | } | |
128 | ||
129 | int sessiond_notify_quit_pipe(void) | |
130 | { | |
131 | return notify_thread_pipe(thread_quit_pipe[1]); | |
132 | } | |
133 | ||
134 | void sessiond_close_quit_pipe(void) | |
135 | { | |
136 | utils_close_pipe(thread_quit_pipe); | |
137 | } | |
138 | ||
99d688f2 JG |
139 | void sessiond_set_client_thread_state(bool running) |
140 | { | |
141 | pthread_mutex_lock(&client_thread_state.lock); | |
142 | client_thread_state.is_running = running; | |
143 | pthread_cond_broadcast(&client_thread_state.cond); | |
144 | pthread_mutex_unlock(&client_thread_state.lock); | |
145 | } | |
146 | ||
147 | void sessiond_wait_client_thread_stopped(void) | |
148 | { | |
149 | pthread_mutex_lock(&client_thread_state.lock); | |
150 | while (client_thread_state.is_running) { | |
151 | pthread_cond_wait(&client_thread_state.cond, | |
152 | &client_thread_state.lock); | |
153 | } | |
154 | pthread_mutex_unlock(&client_thread_state.lock); | |
155 | } | |
156 | ||
a7333da7 JG |
157 | static |
158 | int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size, | |
159 | int *a_pipe) | |
160 | { | |
161 | int ret; | |
162 | ||
163 | assert(events); | |
164 | ||
165 | ret = lttng_poll_create(events, size, LTTNG_CLOEXEC); | |
166 | if (ret < 0) { | |
167 | goto error; | |
168 | } | |
169 | ||
170 | /* Add quit pipe */ | |
171 | ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR); | |
172 | if (ret < 0) { | |
173 | goto error; | |
174 | } | |
175 | ||
176 | return 0; | |
177 | ||
178 | error: | |
179 | return ret; | |
180 | } | |
181 | ||
182 | /* | |
183 | * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set. | |
184 | */ | |
185 | int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size) | |
186 | { | |
187 | return __sessiond_set_thread_pollset(events, size, thread_quit_pipe); | |
188 | } |