src/bin/lttng-relayd/health-relayd.c

   1 /*
   2  * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <fcntl.h>
  10 #include <getopt.h>
  11 #include <grp.h>
  12 #include <limits.h>
  13 #include <pthread.h>
  14 #include <signal.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <sys/ipc.h>
  19 #include <sys/resource.h>
  20 #include <sys/shm.h>
  21 #include <sys/socket.h>
  22 #include <sys/stat.h>
  23 #include <sys/types.h>
  24 #include <urcu/list.h>
  25 #include <poll.h>
  26 #include <unistd.h>
  27 #include <sys/mman.h>
  28 #include <urcu/compiler.h>
  29 #include <inttypes.h>
  30
  31 #include <common/defaults.h>
  32 #include <common/common.h>
  33 #include <common/consumer/consumer.h>
  34 #include <common/consumer/consumer-timer.h>
  35 #include <common/compat/poll.h>
  36 #include <common/sessiond-comm/sessiond-comm.h>
  37 #include <common/utils.h>
  38 #include <common/compat/getenv.h>
  39 #include <common/fd-tracker/utils.h>
  40
  41 #include "lttng-relayd.h"
  42 #include "health-relayd.h"
  43
  44 /* Global health check unix path */
  45 static
  46 char health_unix_sock_path[PATH_MAX];
  47
  48 int health_quit_pipe[2] = { -1, -1 };
  49
  50 /*
  51  * Check if the thread quit pipe was triggered.
  52  *
  53  * Return 1 if it was triggered else 0;
  54  */
  55 static
  56 int check_health_quit_pipe(int fd, uint32_t events)
  57 {
  58         if (fd == health_quit_pipe[0] && (events & LPOLLIN)) {
  59                 return 1;
  60         }
  61
  62         return 0;
  63 }
  64
  65 /*
  66  * Send data on a unix socket using the liblttsessiondcomm API.
  67  *
  68  * Return lttcomm error code.
  69  */
  70 static int send_unix_sock(int sock, void *buf, size_t len)
  71 {
  72         /* Check valid length */
  73         if (len == 0) {
  74                 return -1;
  75         }
  76
  77         return lttcomm_send_unix_sock(sock, buf, len);
  78 }
  79
  80 static int create_lttng_rundir_with_perm(const char *rundir)
  81 {
  82         int ret;
  83
  84         DBG3("Creating LTTng run directory: %s", rundir);
  85
  86         ret = mkdir(rundir, S_IRWXU);
  87         if (ret < 0) {
  88                 if (errno != EEXIST) {
  89                         ERR("Unable to create %s", rundir);
  90                         goto error;
  91                 } else {
  92                         ret = 0;
  93                 }
  94         } else if (ret == 0) {
  95                 int is_root = !getuid();
  96
  97                 if (is_root) {
  98                         gid_t gid;
  99
 100                         ret = utils_get_group_id(tracing_group_name, true, &gid);
 101                         if (ret) {
 102                                 /* Default to root group. */
 103                                 gid = 0;
 104                         }
 105
 106                         ret = chown(rundir, 0, gid);
 107                         if (ret < 0) {
 108                                 ERR("Unable to set group on %s", rundir);
 109                                 PERROR("chown");
 110                                 ret = -1;
 111                                 goto error;
 112                         }
 113
 114                         ret = chmod(rundir,
 115                                         S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
 116                         if (ret < 0) {
 117                                 ERR("Unable to set permissions on %s", health_unix_sock_path);
 118                                 PERROR("chmod");
 119                                 ret = -1;
 120                                 goto error;
 121                         }
 122                 }
 123         }
 124
 125 error:
 126         return ret;
 127 }
 128
 129 static
 130 int parse_health_env(void)
 131 {
 132         const char *health_path;
 133
 134         health_path = lttng_secure_getenv(LTTNG_RELAYD_HEALTH_ENV);
 135         if (health_path) {
 136                 strncpy(health_unix_sock_path, health_path,
 137                         PATH_MAX);
 138                 health_unix_sock_path[PATH_MAX - 1] = '\0';
 139         }
 140
 141         return 0;
 142 }
 143
 144 static
 145 int setup_health_path(void)
 146 {
 147         int is_root, ret = 0;
 148         const char *home_path = NULL;
 149         char *rundir = NULL, *relayd_path = NULL;
 150
 151         ret = parse_health_env();
 152         if (ret) {
 153                 return ret;
 154         }
 155
 156         is_root = !getuid();
 157
 158         if (is_root) {
 159                 rundir = strdup(DEFAULT_LTTNG_RUNDIR);
 160                 if (!rundir) {
 161                         ret = -ENOMEM;
 162                         goto end;
 163                 }
 164         } else {
 165                 /*
 166                  * Create rundir from home path. This will create something like
 167                  * $HOME/.lttng
 168                  */
 169                 home_path = utils_get_home_dir();
 170
 171                 if (home_path == NULL) {
 172                         /* TODO: Add --socket PATH option */
 173                         ERR("Can't get HOME directory for sockets creation.");
 174                         ret = -EPERM;
 175                         goto end;
 176                 }
 177
 178                 ret = asprintf(&rundir, DEFAULT_LTTNG_HOME_RUNDIR, home_path);
 179                 if (ret < 0) {
 180                         ret = -ENOMEM;
 181                         goto end;
 182                 }
 183         }
 184
 185         ret = asprintf(&relayd_path, DEFAULT_RELAYD_PATH, rundir);
 186         if (ret < 0) {
 187                 ret = -ENOMEM;
 188                 goto end;
 189         }
 190
 191         ret = create_lttng_rundir_with_perm(rundir);
 192         if (ret < 0) {
 193                 goto end;
 194         }
 195
 196         ret = create_lttng_rundir_with_perm(relayd_path);
 197         if (ret < 0) {
 198                 goto end;
 199         }
 200
 201         if (is_root) {
 202                 if (strlen(health_unix_sock_path) != 0) {
 203                         goto end;
 204                 }
 205                 snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
 206                         DEFAULT_GLOBAL_RELAY_HEALTH_UNIX_SOCK,
 207                         (int) getpid());
 208         } else {
 209                 /* Set health check Unix path */
 210                 if (strlen(health_unix_sock_path) != 0) {
 211                         goto end;
 212                 }
 213
 214                 snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
 215                         DEFAULT_HOME_RELAY_HEALTH_UNIX_SOCK,
 216                         home_path, (int) getpid());
 217         }
 218
 219 end:
 220         free(rundir);
 221         free(relayd_path);
 222         return ret;
 223 }
 224
 225 static
 226 int accept_unix_socket(void *data, int *out_fd)
 227 {
 228         int ret;
 229         int accepting_sock = *((int *) data);
 230
 231         ret = lttcomm_accept_unix_sock(accepting_sock);
 232         if (ret < 0) {
 233                 goto end;
 234         }
 235
 236         *out_fd = ret;
 237         ret = 0;
 238 end:
 239         return ret;
 240 }
 241
 242 static
 243 int open_unix_socket(void *data, int *out_fd)
 244 {
 245         int ret;
 246         const char *path = data;
 247
 248         ret = lttcomm_create_unix_sock(path);
 249         if (ret < 0) {
 250                 goto end;
 251         }
 252
 253         *out_fd = ret;
 254         ret = 0;
 255 end:
 256         return ret;
 257 }
 258
 259 /*
 260  * Thread managing health check socket.
 261  */
 262 void *thread_manage_health(void *data)
 263 {
 264         int sock = -1, new_sock = -1, ret, i, pollfd, err = -1;
 265         uint32_t revents, nb_fd;
 266         struct lttng_poll_event events;
 267         struct health_comm_msg msg;
 268         struct health_comm_reply reply;
 269         int is_root;
 270         char *sock_name;
 271
 272         DBG("[thread] Manage health check started");
 273
 274         setup_health_path();
 275
 276         rcu_register_thread();
 277
 278         /* We might hit an error path before this is created. */
 279         lttng_poll_init(&events);
 280
 281         /* Create unix socket */
 282         ret = asprintf(&sock_name, "Unix socket @ %s", health_unix_sock_path);
 283         if (ret == -1) {
 284                 PERROR("Failed to allocate unix socket name");
 285                 err = -1;
 286                 goto error;
 287         }
 288         ret = fd_tracker_open_unsuspendable_fd(the_fd_tracker, &sock,
 289                         (const char **) &sock_name, 1, open_unix_socket,
 290                         health_unix_sock_path);
 291         free(sock_name);
 292         if (ret < 0) {
 293                 ERR("Unable to create health check Unix socket");
 294                 err = -1;
 295                 goto error;
 296         }
 297
 298         is_root = !getuid();
 299         if (is_root) {
 300                 /* lttng health client socket path permissions */
 301                 gid_t gid;
 302
 303                 ret = utils_get_group_id(tracing_group_name, true, &gid);
 304                 if (ret) {
 305                         /* Default to root group. */
 306                         gid = 0;
 307                 }
 308
 309                 ret = chown(health_unix_sock_path, 0, gid);
 310                 if (ret < 0) {
 311                         ERR("Unable to set group on %s", health_unix_sock_path);
 312                         PERROR("chown");
 313                         err = -1;
 314                         goto error;
 315                 }
 316
 317                 ret = chmod(health_unix_sock_path,
 318                                 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 319                 if (ret < 0) {
 320                         ERR("Unable to set permissions on %s", health_unix_sock_path);
 321                         PERROR("chmod");
 322                         err = -1;
 323                         goto error;
 324                 }
 325         }
 326
 327         /*
 328          * Set the CLOEXEC flag. Return code is useless because either way, the
 329          * show must go on.
 330          */
 331         (void) utils_set_fd_cloexec(sock);
 332
 333         ret = lttcomm_listen_unix_sock(sock);
 334         if (ret < 0) {
 335                 goto error;
 336         }
 337
 338         /* Size is set to 2 for the unix socket and quit pipe. */
 339         ret = fd_tracker_util_poll_create(the_fd_tracker,
 340                         "Health management thread epoll", &events, 2,
 341                         LTTNG_CLOEXEC);
 342         if (ret < 0) {
 343                 ERR("Poll set creation failed");
 344                 goto error;
 345         }
 346
 347         ret = lttng_poll_add(&events, health_quit_pipe[0], LPOLLIN);
 348         if (ret < 0) {
 349                 goto error;
 350         }
 351
 352         /* Add the application registration socket */
 353         ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLPRI);
 354         if (ret < 0) {
 355                 goto error;
 356         }
 357
 358         lttng_relay_notify_ready();
 359
 360         while (1) {
 361                 char *accepted_socket_name;
 362
 363                 DBG("Health check ready");
 364
 365                 /* Inifinite blocking call, waiting for transmission */
 366 restart:
 367                 ret = lttng_poll_wait(&events, -1);
 368                 if (ret < 0) {
 369                         /*
 370                          * Restart interrupted system call.
 371                          */
 372                         if (errno == EINTR) {
 373                                 goto restart;
 374                         }
 375                         goto error;
 376                 }
 377
 378                 nb_fd = ret;
 379
 380                 for (i = 0; i < nb_fd; i++) {
 381                         /* Fetch once the poll data */
 382                         revents = LTTNG_POLL_GETEV(&events, i);
 383                         pollfd = LTTNG_POLL_GETFD(&events, i);
 384
 385                         /* Thread quit pipe has been closed. Killing thread. */
 386                         ret = check_health_quit_pipe(pollfd, revents);
 387                         if (ret) {
 388                                 err = 0;
 389                                 goto exit;
 390                         }
 391
 392                         /* Event on the registration socket */
 393                         if (pollfd == sock) {
 394                                 if (revents & LPOLLIN) {
 395                                         continue;
 396                                 } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
 397                                         ERR("Health socket poll error");
 398                                         goto error;
 399                                 } else {
 400                                         ERR("Unexpected poll events %u for sock %d", revents, pollfd);
 401                                         goto error;
 402                                 }
 403                         }
 404                 }
 405
 406                 ret = asprintf(&accepted_socket_name, "Socket accepted from unix socket @ %s",
 407                                 health_unix_sock_path);
 408                 if (ret == -1) {
 409                         PERROR("Failed to allocate name of accepted socket from unix socket @ %s",
 410                                         health_unix_sock_path);
 411                         goto error;
 412                 }
 413                 ret = fd_tracker_open_unsuspendable_fd(the_fd_tracker, &new_sock,
 414                                 (const char **) &accepted_socket_name, 1,
 415                                 accept_unix_socket, &sock);
 416                 free(accepted_socket_name);
 417                 if (ret < 0) {
 418                         goto error;
 419                 }
 420
 421                 /*
 422                  * Set the CLOEXEC flag. Return code is useless because either way, the
 423                  * show must go on.
 424                  */
 425                 (void) utils_set_fd_cloexec(new_sock);
 426
 427                 DBG("Receiving data from client for health...");
 428                 ret = lttcomm_recv_unix_sock(new_sock, (void *)&msg, sizeof(msg));
 429                 if (ret <= 0) {
 430                         DBG("Nothing recv() from client... continuing");
 431                         ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker,
 432                                         &new_sock, 1, fd_tracker_util_close_fd,
 433                                         NULL);
 434                         if (ret) {
 435                                 PERROR("close");
 436                         }
 437                         new_sock = -1;
 438                         continue;
 439                 }
 440
 441                 rcu_thread_online();
 442
 443                 LTTNG_ASSERT(msg.cmd == HEALTH_CMD_CHECK);
 444
 445                 memset(&reply, 0, sizeof(reply));
 446                 for (i = 0; i < NR_HEALTH_RELAYD_TYPES; i++) {
 447                         /*
 448                          * health_check_state return 0 if thread is in
 449                          * error.
 450                          */
 451                         if (!health_check_state(health_relayd, i)) {
 452                                 reply.ret_code |= 1ULL << i;
 453                         }
 454                 }
 455
 456                 DBG2("Health check return value %" PRIx64, reply.ret_code);
 457
 458                 ret = send_unix_sock(new_sock, (void *) &reply, sizeof(reply));
 459                 if (ret < 0) {
 460                         ERR("Failed to send health data back to client");
 461                 }
 462
 463                 /* End of transmission */
 464                 ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker,
 465                                 &new_sock, 1, fd_tracker_util_close_fd,
 466                                 NULL);
 467                 if (ret) {
 468                         PERROR("close");
 469                 }
 470                 new_sock = -1;
 471         }
 472
 473 error:
 474         lttng_relay_stop_threads();
 475 exit:
 476         if (err) {
 477                 ERR("Health error occurred in %s", __func__);
 478         }
 479         DBG("Health check thread dying");
 480         unlink(health_unix_sock_path);
 481         if (sock >= 0) {
 482                 ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker, &sock,
 483                                 1, fd_tracker_util_close_fd, NULL);
 484                 if (ret) {
 485                         PERROR("close");
 486                 }
 487         }
 488
 489         /*
 490          * We do NOT rmdir rundir nor the relayd path because there are
 491          * other processes using them.
 492          */
 493
 494         (void) fd_tracker_util_poll_clean(the_fd_tracker, &events);
 495
 496         rcu_unregister_thread();
 497         return NULL;
 498 }