| 1 | /* |
| 2 | * Copyright (C) 2011 EfficiOS Inc. |
| 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0-only |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | #include "manage-apps.h" |
| 11 | #include "testpoint.h" |
| 12 | #include "health-sessiond.h" |
| 13 | #include "utils.h" |
| 14 | #include "thread.h" |
| 15 | |
| 16 | struct thread_notifiers { |
| 17 | struct lttng_pipe *quit_pipe; |
| 18 | int apps_cmd_pipe_read_fd; |
| 19 | }; |
| 20 | |
| 21 | static void cleanup_application_management_thread(void *data) |
| 22 | { |
| 23 | struct thread_notifiers *notifiers = data; |
| 24 | |
| 25 | lttng_pipe_destroy(notifiers->quit_pipe); |
| 26 | free(notifiers); |
| 27 | } |
| 28 | |
| 29 | /* |
| 30 | * This thread receives application command sockets (FDs) on the |
| 31 | * apps_cmd_pipe and waits (polls) on them until they are closed |
| 32 | * or an error occurs. |
| 33 | * |
| 34 | * At that point, it flushes the data (tracing and metadata) associated |
| 35 | * with this application and tears down ust app sessions and other |
| 36 | * associated data structures through ust_app_unregister(). |
| 37 | * |
| 38 | * Note that this thread never sends commands to the applications |
| 39 | * through the command sockets; it merely listens for hang-ups |
| 40 | * and errors on those sockets and cleans-up as they occur. |
| 41 | */ |
| 42 | static void *thread_application_management(void *data) |
| 43 | { |
| 44 | int i, ret, pollfd, err = -1; |
| 45 | ssize_t size_ret; |
| 46 | uint32_t revents, nb_fd; |
| 47 | struct lttng_poll_event events; |
| 48 | struct thread_notifiers *notifiers = data; |
| 49 | const int quit_pipe_read_fd = lttng_pipe_get_readfd( |
| 50 | notifiers->quit_pipe); |
| 51 | |
| 52 | DBG("[thread] Manage application started"); |
| 53 | |
| 54 | rcu_register_thread(); |
| 55 | rcu_thread_online(); |
| 56 | |
| 57 | health_register(the_health_sessiond, HEALTH_SESSIOND_TYPE_APP_MANAGE); |
| 58 | |
| 59 | if (testpoint(sessiond_thread_manage_apps)) { |
| 60 | goto error_testpoint; |
| 61 | } |
| 62 | |
| 63 | health_code_update(); |
| 64 | |
| 65 | ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); |
| 66 | if (ret < 0) { |
| 67 | goto error_poll_create; |
| 68 | } |
| 69 | |
| 70 | ret = lttng_poll_add(&events, notifiers->apps_cmd_pipe_read_fd, |
| 71 | LPOLLIN | LPOLLRDHUP); |
| 72 | if (ret < 0) { |
| 73 | goto error; |
| 74 | } |
| 75 | |
| 76 | ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN | LPOLLERR); |
| 77 | if (ret < 0) { |
| 78 | goto error; |
| 79 | } |
| 80 | |
| 81 | if (testpoint(sessiond_thread_manage_apps_before_loop)) { |
| 82 | goto error; |
| 83 | } |
| 84 | |
| 85 | health_code_update(); |
| 86 | |
| 87 | while (1) { |
| 88 | DBG("Apps thread polling"); |
| 89 | |
| 90 | /* Inifinite blocking call, waiting for transmission */ |
| 91 | restart: |
| 92 | health_poll_entry(); |
| 93 | ret = lttng_poll_wait(&events, -1); |
| 94 | DBG("Apps thread return from poll on %d fds", |
| 95 | LTTNG_POLL_GETNB(&events)); |
| 96 | health_poll_exit(); |
| 97 | if (ret < 0) { |
| 98 | /* |
| 99 | * Restart interrupted system call. |
| 100 | */ |
| 101 | if (errno == EINTR) { |
| 102 | goto restart; |
| 103 | } |
| 104 | goto error; |
| 105 | } |
| 106 | |
| 107 | nb_fd = ret; |
| 108 | |
| 109 | for (i = 0; i < nb_fd; i++) { |
| 110 | /* Fetch once the poll data */ |
| 111 | revents = LTTNG_POLL_GETEV(&events, i); |
| 112 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 113 | |
| 114 | health_code_update(); |
| 115 | |
| 116 | if (pollfd == quit_pipe_read_fd) { |
| 117 | err = 0; |
| 118 | goto exit; |
| 119 | } else if (pollfd == notifiers->apps_cmd_pipe_read_fd) { |
| 120 | /* Inspect the apps cmd pipe */ |
| 121 | if (revents & LPOLLIN) { |
| 122 | int sock; |
| 123 | |
| 124 | /* Empty pipe */ |
| 125 | size_ret = lttng_read( |
| 126 | notifiers->apps_cmd_pipe_read_fd, |
| 127 | &sock, sizeof(sock)); |
| 128 | if (size_ret < sizeof(sock)) { |
| 129 | PERROR("read apps cmd pipe"); |
| 130 | goto error; |
| 131 | } |
| 132 | |
| 133 | health_code_update(); |
| 134 | |
| 135 | /* |
| 136 | * Since this is a command socket (write then read), |
| 137 | * we only monitor the error events of the socket. |
| 138 | */ |
| 139 | ret = lttng_poll_add(&events, sock, |
| 140 | LPOLLERR | LPOLLHUP | LPOLLRDHUP); |
| 141 | if (ret < 0) { |
| 142 | goto error; |
| 143 | } |
| 144 | |
| 145 | DBG("Apps with sock %d added to poll set", sock); |
| 146 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 147 | ERR("Apps command pipe error"); |
| 148 | goto error; |
| 149 | } else { |
| 150 | ERR("Unknown poll events %u for sock %d", revents, pollfd); |
| 151 | goto error; |
| 152 | } |
| 153 | } else { |
| 154 | /* |
| 155 | * At this point, we know that a registered application made |
| 156 | * the event at poll_wait. |
| 157 | */ |
| 158 | if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 159 | /* Removing from the poll set */ |
| 160 | ret = lttng_poll_del(&events, pollfd); |
| 161 | if (ret < 0) { |
| 162 | goto error; |
| 163 | } |
| 164 | |
| 165 | /* Socket closed on remote end. */ |
| 166 | ust_app_unregister(pollfd); |
| 167 | } else { |
| 168 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); |
| 169 | goto error; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | health_code_update(); |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | exit: |
| 178 | error: |
| 179 | lttng_poll_clean(&events); |
| 180 | error_poll_create: |
| 181 | error_testpoint: |
| 182 | |
| 183 | /* |
| 184 | * We don't clean the UST app hash table here since already registered |
| 185 | * applications can still be controlled so let them be until the session |
| 186 | * daemon dies or the applications stop. |
| 187 | */ |
| 188 | |
| 189 | if (err) { |
| 190 | health_error(); |
| 191 | ERR("Health error occurred in %s", __func__); |
| 192 | } |
| 193 | health_unregister(the_health_sessiond); |
| 194 | DBG("Application communication apps thread cleanup complete"); |
| 195 | rcu_thread_offline(); |
| 196 | rcu_unregister_thread(); |
| 197 | return NULL; |
| 198 | } |
| 199 | |
| 200 | static bool shutdown_application_management_thread(void *data) |
| 201 | { |
| 202 | struct thread_notifiers *notifiers = data; |
| 203 | const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe); |
| 204 | |
| 205 | return notify_thread_pipe(write_fd) == 1; |
| 206 | } |
| 207 | |
| 208 | bool launch_application_management_thread(int apps_cmd_pipe_read_fd) |
| 209 | { |
| 210 | struct lttng_pipe *quit_pipe; |
| 211 | struct thread_notifiers *notifiers = NULL; |
| 212 | struct lttng_thread *thread; |
| 213 | |
| 214 | notifiers = zmalloc(sizeof(*notifiers)); |
| 215 | if (!notifiers) { |
| 216 | goto error_alloc; |
| 217 | } |
| 218 | quit_pipe = lttng_pipe_open(FD_CLOEXEC); |
| 219 | if (!quit_pipe) { |
| 220 | goto error; |
| 221 | } |
| 222 | notifiers->quit_pipe = quit_pipe; |
| 223 | notifiers->apps_cmd_pipe_read_fd = apps_cmd_pipe_read_fd; |
| 224 | |
| 225 | thread = lttng_thread_create("UST application management", |
| 226 | thread_application_management, |
| 227 | shutdown_application_management_thread, |
| 228 | cleanup_application_management_thread, |
| 229 | notifiers); |
| 230 | if (!thread) { |
| 231 | goto error; |
| 232 | } |
| 233 | |
| 234 | lttng_thread_put(thread); |
| 235 | return true; |
| 236 | error: |
| 237 | cleanup_application_management_thread(notifiers); |
| 238 | error_alloc: |
| 239 | return false; |
| 240 | } |