Move UST registry into sessiond and implement notifiers
[lttng-tools.git] / src / bin / lttng-sessiond / ust-thread.c
CommitLineData
d0b96690
DG
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
18#include <assert.h>
19
20#include <common/common.h>
21#include <common/utils.h>
22
23#include "fd-limit.h"
24#include "lttng-sessiond.h"
25#include "ust-thread.h"
26
27/*
28 * This thread manage application notify communication.
29 */
30void *ust_thread_manage_notify(void *data)
31{
32 int i, ret, pollfd;
33 uint32_t revents, nb_fd;
34 struct lttng_poll_event events;
35
36 DBG("[ust-thread] Manage application notify command");
37
38 rcu_register_thread();
39 rcu_thread_online();
40
41 ret = sessiond_set_thread_pollset(&events, 2);
42 if (ret < 0) {
43 goto error_poll_create;
44 }
45
46 /* Add notify pipe to the pollset. */
47 ret = lttng_poll_add(&events, apps_cmd_notify_pipe[0], LPOLLIN | LPOLLERR);
48 if (ret < 0) {
49 goto error;
50 }
51
52 while (1) {
53 DBG3("[ust-thread] Manage notify polling on %d fds",
54 LTTNG_POLL_GETNB(&events));
55
56 /* Inifinite blocking call, waiting for transmission */
57restart:
58 ret = lttng_poll_wait(&events, -1);
59 if (ret < 0) {
60 /*
61 * Restart interrupted system call.
62 */
63 if (errno == EINTR) {
64 goto restart;
65 }
66 goto error;
67 }
68
69 nb_fd = ret;
70
71 for (i = 0; i < nb_fd; i++) {
72 /* Fetch once the poll data */
73 revents = LTTNG_POLL_GETEV(&events, i);
74 pollfd = LTTNG_POLL_GETFD(&events, i);
75
76 /* Thread quit pipe has been closed. Killing thread. */
77 ret = sessiond_check_thread_quit_pipe(pollfd, revents);
78 if (ret) {
79 goto exit;
80 }
81
82 /* Inspect the apps cmd pipe */
83 if (pollfd == apps_cmd_notify_pipe[0]) {
84 int sock;
85
86 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
87 ERR("Apps notify command pipe error");
88 goto error;
89 } else if (!(revents & LPOLLIN)) {
90 /* No POLLIN and not a catched error, stop the thread. */
91 ERR("Notify command pipe failed. revent: %u", revents);
92 goto error;
93 }
94
95 do {
96 /* Get socket from dispatch thread. */
97 ret = read(apps_cmd_notify_pipe[0], &sock, sizeof(sock));
98 } while (ret < 0 && errno == EINTR);
99 if (ret < 0 || ret < sizeof(sock)) {
100 PERROR("read apps notify pipe");
101 goto error;
102 }
103
104 ret = lttng_poll_add(&events, sock,
105 LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
106 if (ret < 0) {
107 /*
108 * It's possible we've reached the max poll fd allowed.
109 * Let's close the socket but continue normal execution.
110 */
111 ret = close(sock);
112 if (ret) {
113 PERROR("close notify socket %d", sock);
114 }
115 lttng_fd_put(LTTNG_FD_APPS, 1);
116 continue;
117 }
118 DBG3("UST thread notify added sock %d to pollset", sock);
119 } else {
120 /*
121 * At this point, we know that a registered application
122 * triggered the event.
123 */
124 if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
125 /* Removing from the poll set */
126 ret = lttng_poll_del(&events, pollfd);
127 if (ret < 0) {
128 goto error;
129 }
130
131 ret = close(pollfd);
132 if (ret < 0) {
133 PERROR("close sock %d", pollfd);
134 }
135 lttng_fd_put(LTTNG_FD_APPS, 1);
136 } else if (revents & (LPOLLIN | LPOLLPRI)) {
137 ret = ust_app_recv_notify(pollfd);
138 if (ret < 0) {
139 ret = lttng_poll_del(&events, pollfd);
140 if (ret < 0) {
141 goto error;
142 }
143
144 ret = close(pollfd);
145 if (ret < 0) {
146 PERROR("close sock %d", pollfd);
147 }
148 lttng_fd_put(LTTNG_FD_APPS, 1);
149 }
150 } else {
151 ERR("Unknown poll events %u for sock %d", revents, pollfd);
152 continue;
153 }
154 }
155 }
156 }
157
158exit:
159error:
160 lttng_poll_clean(&events);
161error_poll_create:
162 utils_close_pipe(apps_cmd_notify_pipe);
163 apps_cmd_notify_pipe[0] = apps_cmd_notify_pipe[1] = -1;
164 DBG("Application notify communication apps thread cleanup complete");
165 rcu_thread_offline();
166 rcu_unregister_thread();
167 return NULL;
168}
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