| 1 | /* |
| 2 | * Copyright (C) 2012 David Goulet <dgoulet@efficios.com> |
| 3 | * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #include "health-sessiond.hpp" |
| 10 | #include "lttng-sessiond.hpp" |
| 11 | #include "thread.hpp" |
| 12 | #include "utils.hpp" |
| 13 | |
| 14 | #include <common/error.hpp> |
| 15 | #include <common/macros.hpp> |
| 16 | #include <common/pipe.hpp> |
| 17 | #include <common/utils.hpp> |
| 18 | |
| 19 | #include <inttypes.h> |
| 20 | #include <sys/stat.h> |
| 21 | |
| 22 | namespace { |
| 23 | struct thread_notifiers { |
| 24 | struct lttng_pipe *quit_pipe; |
| 25 | sem_t ready; |
| 26 | }; |
| 27 | } /* namespace */ |
| 28 | |
| 29 | static void mark_thread_as_ready(struct thread_notifiers *notifiers) |
| 30 | { |
| 31 | DBG("Marking health management thread as ready"); |
| 32 | sem_post(¬ifiers->ready); |
| 33 | } |
| 34 | |
| 35 | static void wait_until_thread_is_ready(struct thread_notifiers *notifiers) |
| 36 | { |
| 37 | DBG("Waiting for health management thread to be ready"); |
| 38 | sem_wait(¬ifiers->ready); |
| 39 | DBG("Health management thread is ready"); |
| 40 | } |
| 41 | |
| 42 | static void cleanup_health_management_thread(void *data) |
| 43 | { |
| 44 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
| 45 | |
| 46 | lttng_pipe_destroy(notifiers->quit_pipe); |
| 47 | sem_destroy(¬ifiers->ready); |
| 48 | free(notifiers); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * Thread managing health check socket. |
| 53 | */ |
| 54 | static void *thread_manage_health(void *data) |
| 55 | { |
| 56 | const bool is_root = (getuid() == 0); |
| 57 | int sock = -1, new_sock = -1, ret, i, err = -1; |
| 58 | uint32_t nb_fd; |
| 59 | struct lttng_poll_event events; |
| 60 | struct health_comm_msg msg; |
| 61 | struct health_comm_reply reply; |
| 62 | /* Thread-specific quit pipe. */ |
| 63 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
| 64 | const auto thread_quit_pipe_fd = lttng_pipe_get_readfd(notifiers->quit_pipe); |
| 65 | |
| 66 | DBG("[thread] Manage health check started"); |
| 67 | |
| 68 | rcu_register_thread(); |
| 69 | |
| 70 | /* |
| 71 | * Created with a size of two for: |
| 72 | * - health client socket |
| 73 | * - thread quit pipe |
| 74 | */ |
| 75 | ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); |
| 76 | if (ret < 0) { |
| 77 | goto error; |
| 78 | } |
| 79 | |
| 80 | /* Create unix socket */ |
| 81 | sock = lttcomm_create_unix_sock(the_config.health_unix_sock_path.value); |
| 82 | if (sock < 0) { |
| 83 | ERR("Unable to create health check Unix socket"); |
| 84 | goto error; |
| 85 | } |
| 86 | |
| 87 | if (is_root) { |
| 88 | /* lttng health client socket path permissions */ |
| 89 | gid_t gid; |
| 90 | |
| 91 | ret = utils_get_group_id(the_config.tracing_group_name.value, true, &gid); |
| 92 | if (ret) { |
| 93 | /* Default to root group. */ |
| 94 | gid = 0; |
| 95 | } |
| 96 | |
| 97 | ret = chown(the_config.health_unix_sock_path.value, 0, gid); |
| 98 | if (ret < 0) { |
| 99 | ERR("Unable to set group on %s", the_config.health_unix_sock_path.value); |
| 100 | PERROR("chown"); |
| 101 | goto error; |
| 102 | } |
| 103 | |
| 104 | ret = chmod(the_config.health_unix_sock_path.value, |
| 105 | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP); |
| 106 | if (ret < 0) { |
| 107 | ERR("Unable to set permissions on %s", |
| 108 | the_config.health_unix_sock_path.value); |
| 109 | PERROR("chmod"); |
| 110 | goto error; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * Set the CLOEXEC flag. Return code is useless because either way, the |
| 116 | * show must go on. |
| 117 | */ |
| 118 | (void) utils_set_fd_cloexec(sock); |
| 119 | |
| 120 | ret = lttcomm_listen_unix_sock(sock); |
| 121 | if (ret < 0) { |
| 122 | goto error; |
| 123 | } |
| 124 | |
| 125 | ret = lttng_poll_add(&events, thread_quit_pipe_fd, LPOLLIN); |
| 126 | if (ret < 0) { |
| 127 | goto error; |
| 128 | } |
| 129 | |
| 130 | /* Add the health client socket. */ |
| 131 | ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLPRI); |
| 132 | if (ret < 0) { |
| 133 | goto error; |
| 134 | } |
| 135 | |
| 136 | mark_thread_as_ready(notifiers); |
| 137 | while (true) { |
| 138 | DBG("Health check ready"); |
| 139 | |
| 140 | /* Infinite blocking call, waiting for transmission */ |
| 141 | restart: |
| 142 | ret = lttng_poll_wait(&events, -1); |
| 143 | if (ret < 0) { |
| 144 | /* |
| 145 | * Restart interrupted system call. |
| 146 | */ |
| 147 | if (errno == EINTR) { |
| 148 | goto restart; |
| 149 | } |
| 150 | goto error; |
| 151 | } |
| 152 | |
| 153 | nb_fd = ret; |
| 154 | |
| 155 | for (i = 0; i < nb_fd; i++) { |
| 156 | /* Fetch once the poll data */ |
| 157 | const auto revents = LTTNG_POLL_GETEV(&events, i); |
| 158 | const auto pollfd = LTTNG_POLL_GETFD(&events, i); |
| 159 | |
| 160 | /* Activity on thread quit pipe, exiting. */ |
| 161 | if (pollfd == thread_quit_pipe_fd) { |
| 162 | DBG("Activity on thread quit pipe"); |
| 163 | err = 0; |
| 164 | goto exit; |
| 165 | } |
| 166 | |
| 167 | /* Event on the health client socket. */ |
| 168 | if (revents & LPOLLIN) { |
| 169 | continue; |
| 170 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 171 | ERR("Health socket poll error"); |
| 172 | goto error; |
| 173 | } else { |
| 174 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); |
| 175 | goto error; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | new_sock = lttcomm_accept_unix_sock(sock); |
| 180 | if (new_sock < 0) { |
| 181 | goto error; |
| 182 | } |
| 183 | |
| 184 | /* |
| 185 | * Set the CLOEXEC flag. Return code is useless because either way, the |
| 186 | * show must go on. |
| 187 | */ |
| 188 | (void) utils_set_fd_cloexec(new_sock); |
| 189 | |
| 190 | DBG("Receiving data from client for health..."); |
| 191 | ret = lttcomm_recv_unix_sock(new_sock, (void *) &msg, sizeof(msg)); |
| 192 | if (ret <= 0) { |
| 193 | DBG("Nothing recv() from client... continuing"); |
| 194 | ret = close(new_sock); |
| 195 | if (ret) { |
| 196 | PERROR("close"); |
| 197 | } |
| 198 | continue; |
| 199 | } |
| 200 | |
| 201 | rcu_thread_online(); |
| 202 | |
| 203 | memset(&reply, 0, sizeof(reply)); |
| 204 | for (i = 0; i < NR_HEALTH_SESSIOND_TYPES; i++) { |
| 205 | /* |
| 206 | * health_check_state returns 0 if health is |
| 207 | * bad. |
| 208 | */ |
| 209 | if (!health_check_state(the_health_sessiond, i)) { |
| 210 | reply.ret_code |= 1ULL << i; |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | DBG2("Health check return value %" PRIx64, reply.ret_code); |
| 215 | |
| 216 | ret = lttcomm_send_unix_sock(new_sock, (void *) &reply, sizeof(reply)); |
| 217 | if (ret < 0) { |
| 218 | ERR("Failed to send health data back to client"); |
| 219 | } |
| 220 | |
| 221 | /* End of transmission */ |
| 222 | ret = close(new_sock); |
| 223 | if (ret) { |
| 224 | PERROR("close"); |
| 225 | } |
| 226 | } |
| 227 | |
| 228 | exit: |
| 229 | error: |
| 230 | if (err) { |
| 231 | ERR("Health error occurred in %s", __func__); |
| 232 | } |
| 233 | DBG("Health check thread dying"); |
| 234 | unlink(the_config.health_unix_sock_path.value); |
| 235 | if (sock >= 0) { |
| 236 | ret = close(sock); |
| 237 | if (ret) { |
| 238 | PERROR("close"); |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | lttng_poll_clean(&events); |
| 243 | rcu_unregister_thread(); |
| 244 | return nullptr; |
| 245 | } |
| 246 | |
| 247 | static bool shutdown_health_management_thread(void *data) |
| 248 | { |
| 249 | struct thread_notifiers *notifiers = (thread_notifiers *) data; |
| 250 | const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe); |
| 251 | |
| 252 | return notify_thread_pipe(write_fd) == 1; |
| 253 | } |
| 254 | |
| 255 | bool launch_health_management_thread() |
| 256 | { |
| 257 | struct thread_notifiers *notifiers; |
| 258 | struct lttng_thread *thread; |
| 259 | |
| 260 | notifiers = zmalloc<thread_notifiers>(); |
| 261 | if (!notifiers) { |
| 262 | goto error_alloc; |
| 263 | } |
| 264 | |
| 265 | sem_init(¬ifiers->ready, 0, 0); |
| 266 | notifiers->quit_pipe = lttng_pipe_open(FD_CLOEXEC); |
| 267 | if (!notifiers->quit_pipe) { |
| 268 | goto error; |
| 269 | } |
| 270 | thread = lttng_thread_create("Health management", |
| 271 | thread_manage_health, |
| 272 | shutdown_health_management_thread, |
| 273 | cleanup_health_management_thread, |
| 274 | notifiers); |
| 275 | if (!thread) { |
| 276 | goto error; |
| 277 | } |
| 278 | |
| 279 | wait_until_thread_is_ready(notifiers); |
| 280 | lttng_thread_put(thread); |
| 281 | return true; |
| 282 | error: |
| 283 | cleanup_health_management_thread(notifiers); |
| 284 | error_alloc: |
| 285 | return false; |
| 286 | } |