| 1 | /* |
| 2 | * Copyright (C) 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License, version 2 only, |
| 6 | * as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License along |
| 14 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 16 | */ |
| 17 | |
| 18 | #define _LGPL_SOURCE |
| 19 | #include <assert.h> |
| 20 | |
| 21 | #include <common/hashtable/hashtable.h> |
| 22 | #include <common/common.h> |
| 23 | #include <common/utils.h> |
| 24 | #include <pthread.h> |
| 25 | |
| 26 | #include "lttng-sessiond.h" |
| 27 | #include "health-sessiond.h" |
| 28 | #include "testpoint.h" |
| 29 | #include "utils.h" |
| 30 | #include "ht-cleanup.h" |
| 31 | |
| 32 | static int ht_cleanup_quit_pipe[2] = { -1, -1 }; |
| 33 | |
| 34 | /* |
| 35 | * Check if the ht_cleanup thread quit pipe was triggered. |
| 36 | * |
| 37 | * Return true if it was triggered else false; |
| 38 | */ |
| 39 | static bool check_quit_pipe(int fd, uint32_t events) |
| 40 | { |
| 41 | return (fd == ht_cleanup_quit_pipe[0] && (events & LPOLLIN)); |
| 42 | } |
| 43 | |
| 44 | static int init_pipe(int *pipe_fds) |
| 45 | { |
| 46 | int ret, i; |
| 47 | |
| 48 | ret = pipe(pipe_fds); |
| 49 | if (ret < 0) { |
| 50 | PERROR("ht_cleanup thread quit pipe"); |
| 51 | goto error; |
| 52 | } |
| 53 | |
| 54 | for (i = 0; i < 2; i++) { |
| 55 | ret = fcntl(pipe_fds[i], F_SETFD, FD_CLOEXEC); |
| 56 | if (ret < 0) { |
| 57 | PERROR("fcntl ht_cleanup_quit_pipe"); |
| 58 | goto error; |
| 59 | } |
| 60 | } |
| 61 | error: |
| 62 | return ret; |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set. |
| 67 | */ |
| 68 | static int set_pollset(struct lttng_poll_event *events, size_t size) |
| 69 | { |
| 70 | int ret; |
| 71 | |
| 72 | ret = lttng_poll_create(events, size, LTTNG_CLOEXEC); |
| 73 | if (ret < 0) { |
| 74 | goto error; |
| 75 | } |
| 76 | |
| 77 | ret = lttng_poll_add(events, ht_cleanup_quit_pipe[0], |
| 78 | LPOLLIN | LPOLLERR); |
| 79 | if (ret < 0) { |
| 80 | goto error; |
| 81 | } |
| 82 | |
| 83 | ret = lttng_poll_add(events, ht_cleanup_pipe[0], LPOLLIN | LPOLLERR); |
| 84 | if (ret < 0) { |
| 85 | DBG("[ht-thread] lttng_poll_add error %d.", ret); |
| 86 | goto error; |
| 87 | } |
| 88 | |
| 89 | return 0; |
| 90 | |
| 91 | error: |
| 92 | return ret; |
| 93 | } |
| 94 | |
| 95 | static void cleanup_ht_cleanup_thread(void *data) |
| 96 | { |
| 97 | utils_close_pipe(ht_cleanup_quit_pipe); |
| 98 | utils_close_pipe(ht_cleanup_pipe); |
| 99 | } |
| 100 | |
| 101 | static void *thread_ht_cleanup(void *data) |
| 102 | { |
| 103 | int ret, i, pollfd, err = -1; |
| 104 | ssize_t size_ret; |
| 105 | uint32_t revents, nb_fd; |
| 106 | struct lttng_poll_event events; |
| 107 | |
| 108 | DBG("[ht-thread] startup."); |
| 109 | |
| 110 | rcu_register_thread(); |
| 111 | rcu_thread_online(); |
| 112 | |
| 113 | health_register(health_sessiond, HEALTH_SESSIOND_TYPE_HT_CLEANUP); |
| 114 | |
| 115 | if (testpoint(sessiond_thread_ht_cleanup)) { |
| 116 | DBG("[ht-thread] testpoint."); |
| 117 | goto error_testpoint; |
| 118 | } |
| 119 | |
| 120 | health_code_update(); |
| 121 | |
| 122 | ret = set_pollset(&events, 2); |
| 123 | if (ret < 0) { |
| 124 | DBG("[ht-thread] sessiond_set_ht_cleanup_thread_pollset error %d.", ret); |
| 125 | goto error_poll_create; |
| 126 | } |
| 127 | |
| 128 | health_code_update(); |
| 129 | |
| 130 | while (1) { |
| 131 | restart: |
| 132 | DBG3("[ht-thread] Polling."); |
| 133 | health_poll_entry(); |
| 134 | ret = lttng_poll_wait(&events, -1); |
| 135 | DBG3("[ht-thread] Returning from poll on %d fds.", |
| 136 | LTTNG_POLL_GETNB(&events)); |
| 137 | health_poll_exit(); |
| 138 | if (ret < 0) { |
| 139 | /* |
| 140 | * Restart interrupted system call. |
| 141 | */ |
| 142 | if (errno == EINTR) { |
| 143 | continue; |
| 144 | } |
| 145 | goto error; |
| 146 | } |
| 147 | |
| 148 | nb_fd = ret; |
| 149 | for (i = 0; i < nb_fd; i++) { |
| 150 | struct lttng_ht *ht; |
| 151 | |
| 152 | health_code_update(); |
| 153 | |
| 154 | /* Fetch once the poll data */ |
| 155 | revents = LTTNG_POLL_GETEV(&events, i); |
| 156 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 157 | |
| 158 | if (!revents) { |
| 159 | /* No activity for this FD (poll implementation). */ |
| 160 | continue; |
| 161 | } |
| 162 | |
| 163 | if (pollfd != ht_cleanup_pipe[0]) { |
| 164 | continue; |
| 165 | } |
| 166 | |
| 167 | if (revents & LPOLLIN) { |
| 168 | /* Get socket from dispatch thread. */ |
| 169 | size_ret = lttng_read(ht_cleanup_pipe[0], &ht, |
| 170 | sizeof(ht)); |
| 171 | if (size_ret < sizeof(ht)) { |
| 172 | PERROR("ht cleanup notify pipe"); |
| 173 | goto error; |
| 174 | } |
| 175 | health_code_update(); |
| 176 | /* |
| 177 | * The whole point of this thread is to call |
| 178 | * lttng_ht_destroy from a context that is NOT: |
| 179 | * 1) a read-side RCU lock, |
| 180 | * 2) a call_rcu thread. |
| 181 | */ |
| 182 | lttng_ht_destroy(ht); |
| 183 | |
| 184 | health_code_update(); |
| 185 | |
| 186 | /* |
| 187 | * Ensure that we never process the quit pipe |
| 188 | * event while there is still data available |
| 189 | * on the ht clean pipe. |
| 190 | */ |
| 191 | goto restart; |
| 192 | } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { |
| 193 | ERR("ht cleanup pipe error"); |
| 194 | goto error; |
| 195 | } else { |
| 196 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); |
| 197 | goto error; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | for (i = 0; i < nb_fd; i++) { |
| 202 | health_code_update(); |
| 203 | |
| 204 | /* Fetch once the poll data */ |
| 205 | revents = LTTNG_POLL_GETEV(&events, i); |
| 206 | pollfd = LTTNG_POLL_GETFD(&events, i); |
| 207 | |
| 208 | if (!revents) { |
| 209 | /* No activity for this FD (poll implementation). */ |
| 210 | continue; |
| 211 | } |
| 212 | |
| 213 | if (pollfd == ht_cleanup_pipe[0]) { |
| 214 | continue; |
| 215 | } |
| 216 | |
| 217 | /* Thread quit pipe has been closed. Killing thread. */ |
| 218 | ret = check_quit_pipe(pollfd, revents); |
| 219 | if (ret) { |
| 220 | err = 0; |
| 221 | DBG("[ht-cleanup] quit."); |
| 222 | goto exit; |
| 223 | } |
| 224 | } |
| 225 | } |
| 226 | |
| 227 | exit: |
| 228 | error: |
| 229 | lttng_poll_clean(&events); |
| 230 | error_poll_create: |
| 231 | error_testpoint: |
| 232 | DBG("[ht-cleanup] Thread terminates."); |
| 233 | if (err) { |
| 234 | health_error(); |
| 235 | ERR("Health error occurred in %s", __func__); |
| 236 | } |
| 237 | health_unregister(health_sessiond); |
| 238 | rcu_thread_offline(); |
| 239 | rcu_unregister_thread(); |
| 240 | return NULL; |
| 241 | } |
| 242 | |
| 243 | static bool shutdown_ht_cleanup_thread(void *data) |
| 244 | { |
| 245 | int ret; |
| 246 | |
| 247 | ret = notify_thread_pipe(ht_cleanup_quit_pipe[1]); |
| 248 | if (ret < 0) { |
| 249 | ERR("write error on ht_cleanup quit pipe"); |
| 250 | goto end; |
| 251 | } |
| 252 | end: |
| 253 | return ret; |
| 254 | } |
| 255 | |
| 256 | struct lttng_thread *launch_ht_cleanup_thread(void) |
| 257 | { |
| 258 | int ret; |
| 259 | struct lttng_thread *thread; |
| 260 | |
| 261 | ret = init_pipe(ht_cleanup_pipe); |
| 262 | if (ret) { |
| 263 | goto error; |
| 264 | } |
| 265 | |
| 266 | ret = init_pipe(ht_cleanup_quit_pipe); |
| 267 | if (ret) { |
| 268 | goto error; |
| 269 | } |
| 270 | |
| 271 | thread = lttng_thread_create("HT cleanup", |
| 272 | thread_ht_cleanup, |
| 273 | shutdown_ht_cleanup_thread, |
| 274 | cleanup_ht_cleanup_thread, |
| 275 | NULL); |
| 276 | if (!thread) { |
| 277 | ret = -1; |
| 278 | goto error; |
| 279 | } |
| 280 | return thread; |
| 281 | error: |
| 282 | cleanup_ht_cleanup_thread(NULL); |
| 283 | return NULL; |
| 284 | } |