src/lxc/start.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  * Serge Hallyn <serge@hallyn.com>
   9  * Christian Brauner <christian.brauner@ubuntu.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #define _GNU_SOURCE
  27 #include "config.h"
  28
  29 #include <alloca.h>
  30 #include <dirent.h>
  31 #include <errno.h>
  32 #include <fcntl.h>
  33 #include <grp.h>
  34 #include <poll.h>
  35 #include <signal.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40 #include <sys/file.h>
  41 #include <sys/mount.h>
  42 #include <sys/param.h>
  43 #include <sys/prctl.h>
  44 #include <sys/socket.h>
  45 #include <sys/stat.h>
  46 #include <sys/syscall.h>
  47 #include <sys/types.h>
  48 #include <sys/un.h>
  49 #include <sys/wait.h>
  50
  51 #if HAVE_LIBCAP
  52 #include <sys/capability.h>
  53 #endif
  54
  55 #ifndef HAVE_DECL_PR_CAPBSET_DROP
  56 #define PR_CAPBSET_DROP 24
  57 #endif
  58
  59 #ifndef HAVE_DECL_PR_SET_NO_NEW_PRIVS
  60 #define PR_SET_NO_NEW_PRIVS 38
  61 #endif
  62
  63 #ifndef HAVE_DECL_PR_GET_NO_NEW_PRIVS
  64 #define PR_GET_NO_NEW_PRIVS 39
  65 #endif
  66
  67 #include "af_unix.h"
  68 #include "caps.h"
  69 #include "cgroup.h"
  70 #include "commands.h"
  71 #include "commands_utils.h"
  72 #include "conf.h"
  73 #include "confile_utils.h"
  74 #include "console.h"
  75 #include "error.h"
  76 #include "log.h"
  77 #include "lxccontainer.h"
  78 #include "lxclock.h"
  79 #include "lxcseccomp.h"
  80 #include "mainloop.h"
  81 #include "monitor.h"
  82 #include "namespace.h"
  83 #include "network.h"
  84 #include "start.h"
  85 #include "storage.h"
  86 #include "storage_utils.h"
  87 #include "sync.h"
  88 #include "utils.h"
  89 #include "lsm/lsm.h"
  90
  91 lxc_log_define(lxc_start, lxc);
  92
  93 extern void mod_all_rdeps(struct lxc_container *c, bool inc);
  94 static bool do_destroy_container(struct lxc_handler *handler);
  95 static int lxc_rmdir_onedev_wrapper(void *data);
  96 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
  97                                             const char *name);
  98
  99 static void print_top_failing_dir(const char *path)
 100 {
 101         size_t len = strlen(path);
 102         char *copy = alloca(len + 1), *p, *e, saved;
 103         strcpy(copy, path);
 104
 105         p = copy;
 106         e = copy + len;
 107         while (p < e) {
 108                 while (p < e && *p == '/')
 109                         p++;
 110                 while (p < e && *p != '/')
 111                         p++;
 112                 saved = *p;
 113                 *p = '\0';
 114                 if (access(copy, X_OK)) {
 115                         SYSERROR("Could not access %s. Please grant it x "
 116                                  "access, or add an ACL for the container "
 117                                  "root.", copy);
 118                         return;
 119                 }
 120                 *p = saved;
 121         }
 122 }
 123
 124 static void close_ns(int ns_fd[LXC_NS_MAX])
 125 {
 126         int i;
 127
 128         for (i = 0; i < LXC_NS_MAX; i++) {
 129                 if (ns_fd[i] > -1) {
 130                         close(ns_fd[i]);
 131                         ns_fd[i] = -1;
 132                 }
 133         }
 134 }
 135
 136 /* preserve_ns: open /proc/@pid/ns/@ns for each namespace specified
 137  * in clone_flags.
 138  * Return true on success, false on failure.
 139  */
 140 static bool preserve_ns(int ns_fd[LXC_NS_MAX], int clone_flags, pid_t pid)
 141 {
 142         int i, ret;
 143
 144         for (i = 0; i < LXC_NS_MAX; i++)
 145                 ns_fd[i] = -1;
 146
 147         ret = lxc_preserve_ns(pid, "");
 148         if (ret < 0) {
 149                 SYSERROR("Kernel does not support attaching to namespaces.");
 150                 return false;
 151         } else {
 152                 close(ret);
 153         }
 154
 155         for (i = 0; i < LXC_NS_MAX; i++) {
 156                 if ((clone_flags & ns_info[i].clone_flag) == 0)
 157                         continue;
 158                 ns_fd[i] = lxc_preserve_ns(pid, ns_info[i].proc_name);
 159                 if (ns_fd[i] < 0)
 160                         goto error;
 161         }
 162
 163         return true;
 164
 165 error:
 166         if (errno == ENOENT)
 167                 SYSERROR("Kernel does not support attaching to %s namespaces.", ns_info[i].proc_name);
 168         else
 169                 SYSERROR("Failed to open file descriptor for %s namespace: %s.", ns_info[i].proc_name, strerror(errno));
 170         close_ns(ns_fd);
 171         return false;
 172 }
 173
 174 static int attach_ns(const int ns_fd[LXC_NS_MAX]) {
 175         int i;
 176
 177         for (i = 0; i < LXC_NS_MAX; i++) {
 178                 if (ns_fd[i] < 0)
 179                         continue;
 180
 181                 if (setns(ns_fd[i], 0) != 0)
 182                         goto error;
 183         }
 184         return 0;
 185
 186 error:
 187         SYSERROR("Failed to attach %s namespace.", ns_info[i].proc_name);
 188         return -1;
 189 }
 190
 191 static int match_fd(int fd)
 192 {
 193         return (fd == 0 || fd == 1 || fd == 2);
 194 }
 195
 196 int lxc_check_inherited(struct lxc_conf *conf, bool closeall,
 197                         int *fds_to_ignore, size_t len_fds)
 198 {
 199         struct dirent *direntp;
 200         int fd, fddir;
 201         size_t i;
 202         DIR *dir;
 203
 204         if (conf && conf->close_all_fds)
 205                 closeall = true;
 206
 207 restart:
 208         dir = opendir("/proc/self/fd");
 209         if (!dir) {
 210                 WARN("Failed to open directory: %s.", strerror(errno));
 211                 return -1;
 212         }
 213
 214         fddir = dirfd(dir);
 215
 216         while ((direntp = readdir(dir))) {
 217                 if (!direntp)
 218                         break;
 219
 220                 if (!strcmp(direntp->d_name, "."))
 221                         continue;
 222
 223                 if (!strcmp(direntp->d_name, ".."))
 224                         continue;
 225
 226                 if (lxc_safe_int(direntp->d_name, &fd) < 0) {
 227                         INFO("Could not parse file descriptor for: %s", direntp->d_name);
 228                         continue;
 229                 }
 230
 231                 for (i = 0; i < len_fds; i++)
 232                         if (fds_to_ignore[i] == fd)
 233                                 break;
 234
 235                 if (fd == fddir || fd == lxc_log_fd ||
 236                     (i < len_fds && fd == fds_to_ignore[i]))
 237                         continue;
 238
 239                 if (conf) {
 240                         for (i = 0; i < LXC_NS_MAX; i++)
 241                                 if (conf->inherit_ns_fd[i] == fd)
 242                                         break;
 243
 244                         if (i < LXC_NS_MAX)
 245                                 continue;
 246                 }
 247
 248                 if (current_config && fd == current_config->logfd)
 249                         continue;
 250
 251                 if (match_fd(fd))
 252                         continue;
 253
 254                 if (closeall) {
 255                         close(fd);
 256                         closedir(dir);
 257                         INFO("Closed inherited fd: %d.", fd);
 258                         goto restart;
 259                 }
 260                 WARN("Inherited fd: %d.", fd);
 261         }
 262
 263         /* Only enable syslog at this point to avoid the above logging function
 264          * to open a new fd and make the check_inherited function enter an
 265          * infinite loop.
 266          */
 267         lxc_log_enable_syslog();
 268
 269         closedir(dir); /* cannot fail */
 270         return 0;
 271 }
 272
 273 static int setup_signal_fd(sigset_t *oldmask)
 274 {
 275         sigset_t mask;
 276         int fd;
 277
 278         /* Block everything except serious error signals. */
 279         if (sigfillset(&mask) ||
 280             sigdelset(&mask, SIGILL) ||
 281             sigdelset(&mask, SIGSEGV) ||
 282             sigdelset(&mask, SIGBUS) ||
 283             sigdelset(&mask, SIGWINCH) ||
 284             sigprocmask(SIG_BLOCK, &mask, oldmask)) {
 285                 SYSERROR("Failed to set signal mask.");
 286                 return -1;
 287         }
 288
 289         fd = signalfd(-1, &mask, 0);
 290         if (fd < 0) {
 291                 SYSERROR("Failed to create signal file descriptor.");
 292                 return -1;
 293         }
 294
 295         if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
 296                 SYSERROR("Failed to set FD_CLOEXEC on the signal file descriptor: %d.", fd);
 297                 close(fd);
 298                 return -1;
 299         }
 300
 301         DEBUG("Set SIGCHLD handler with file descriptor: %d.", fd);
 302
 303         return fd;
 304 }
 305
 306 static int signal_handler(int fd, uint32_t events, void *data,
 307                           struct lxc_epoll_descr *descr)
 308 {
 309         struct signalfd_siginfo siginfo;
 310         siginfo_t info;
 311         int ret;
 312         pid_t *pid = data;
 313         bool init_died = false;
 314
 315         ret = read(fd, &siginfo, sizeof(siginfo));
 316         if (ret < 0) {
 317                 ERROR("Failed to read signal info from signal file descriptor: %d.", fd);
 318                 return -1;
 319         }
 320
 321         if (ret != sizeof(siginfo)) {
 322                 ERROR("Unexpected size for siginfo struct.");
 323                 return -1;
 324         }
 325
 326         /* Check whether init is running. */
 327         info.si_pid = 0;
 328         ret = waitid(P_PID, *pid, &info, WEXITED | WNOWAIT | WNOHANG);
 329         if (ret == 0 && info.si_pid == *pid)
 330                 init_died = true;
 331
 332         if (siginfo.ssi_signo != SIGCHLD) {
 333                 kill(*pid, siginfo.ssi_signo);
 334                 INFO("Forwarded signal %d to pid %d.", siginfo.ssi_signo, *pid);
 335                 return init_died ? 1 : 0;
 336         }
 337
 338         if (siginfo.ssi_code == CLD_STOPPED) {
 339                 INFO("Container init process was stopped.");
 340                 return init_died ? 1 : 0;
 341         } else if (siginfo.ssi_code == CLD_CONTINUED) {
 342                 INFO("Container init process was continued.");
 343                 return init_died ? 1 : 0;
 344         }
 345
 346         /* More robustness, protect ourself from a SIGCHLD sent
 347          * by a process different from the container init.
 348          */
 349         if (siginfo.ssi_pid != *pid) {
 350                 NOTICE("Received SIGCHLD from pid %d instead of container init %d.", siginfo.ssi_pid, *pid);
 351                 return init_died ? 1 : 0;
 352         }
 353
 354         DEBUG("Container init process %d exited.", *pid);
 355         return 1;
 356 }
 357
 358 static int lxc_serve_state_clients(const char *name,
 359                                    struct lxc_handler *handler,
 360                                    lxc_state_t state)
 361 {
 362         ssize_t ret;
 363         struct lxc_list *cur, *next;
 364         struct state_client *client;
 365         struct lxc_msg msg = {.type = lxc_msg_state, .value = state};
 366
 367         process_lock();
 368
 369         /* Only set state under process lock held so that we don't cause
 370         *  lxc_cmd_add_state_client() to miss a state.
 371          */
 372         handler->state = state;
 373         TRACE("set container state to %s", lxc_state2str(state));
 374
 375         if (lxc_list_empty(&handler->state_clients)) {
 376                 TRACE("no state clients registered");
 377                 process_unlock();
 378                 lxc_monitor_send_state(name, state, handler->lxcpath);
 379                 return 0;
 380         }
 381
 382         strncpy(msg.name, name, sizeof(msg.name));
 383         msg.name[sizeof(msg.name) - 1] = 0;
 384
 385         lxc_list_for_each_safe(cur, &handler->state_clients, next) {
 386                 client = cur->elem;
 387
 388                 if (!client->states[state]) {
 389                         TRACE("state %s not registered for state client %d",
 390                               lxc_state2str(state), client->clientfd);
 391                         continue;
 392                 }
 393
 394                 TRACE("sending state %s to state client %d",
 395                       lxc_state2str(state), client->clientfd);
 396
 397         again:
 398                 ret = send(client->clientfd, &msg, sizeof(msg), 0);
 399                 if (ret <= 0) {
 400                         if (errno == EINTR) {
 401                                 TRACE("Caught EINTR; retrying");
 402                                 goto again;
 403                         }
 404
 405                         ERROR("failed to send message to client");
 406                 }
 407
 408                 /* kick client from list */
 409                 close(client->clientfd);
 410                 lxc_list_del(cur);
 411                 free(cur->elem);
 412                 free(cur);
 413         }
 414         process_unlock();
 415
 416         return 0;
 417 }
 418
 419 static int lxc_serve_state_socket_pair(const char *name,
 420                                        struct lxc_handler *handler,
 421                                        lxc_state_t state)
 422 {
 423         ssize_t ret;
 424
 425         if (!handler->backgrounded ||
 426             handler->state_socket_pair[1] < 0 ||
 427             state == STARTING)
 428                 return 0;
 429
 430         /* Close read end of the socket pair. */
 431         close(handler->state_socket_pair[0]);
 432         handler->state_socket_pair[0] = -1;
 433
 434 again:
 435         ret = lxc_abstract_unix_send_credential(handler->state_socket_pair[1],
 436                                                 &(int){state}, sizeof(int));
 437         if (ret != sizeof(int)) {
 438                 if (errno == EINTR)
 439                         goto again;
 440                 SYSERROR("Failed to send state to %d",
 441                          handler->state_socket_pair[1]);
 442                 return -1;
 443         }
 444
 445         TRACE("Sent container state \"%s\" to %d", lxc_state2str(state),
 446               handler->state_socket_pair[1]);
 447
 448         /* Close write end of the socket pair. */
 449         close(handler->state_socket_pair[1]);
 450         handler->state_socket_pair[1] = -1;
 451
 452         return 0;
 453 }
 454
 455 int lxc_set_state(const char *name, struct lxc_handler *handler,
 456                   lxc_state_t state)
 457 {
 458         int ret;
 459
 460         ret = lxc_serve_state_socket_pair(name, handler, state);
 461         if (ret < 0) {
 462                 ERROR("Failed to synchronize via anonymous pair of unix sockets");
 463                 return -1;
 464         }
 465
 466         ret = lxc_serve_state_clients(name, handler, state);
 467         if (ret < 0)
 468                 return -1;
 469
 470         /* This function will try to connect to the legacy lxc-monitord state
 471          * server and only exists for backwards compatibility.
 472          */
 473         lxc_monitor_send_state(name, state, handler->lxcpath);
 474
 475         return 0;
 476 }
 477
 478 int lxc_poll(const char *name, struct lxc_handler *handler)
 479 {
 480         int sigfd = handler->sigfd;
 481         int pid = handler->pid;
 482         struct lxc_epoll_descr descr;
 483
 484         if (lxc_mainloop_open(&descr)) {
 485                 ERROR("Failed to create LXC mainloop.");
 486                 goto out_sigfd;
 487         }
 488
 489         if (lxc_mainloop_add_handler(&descr, sigfd, signal_handler, &pid)) {
 490                 ERROR("Failed to add signal handler with file descriptor %d to LXC mainloop.", sigfd);
 491                 goto out_mainloop_open;
 492         }
 493
 494         if (lxc_console_mainloop_add(&descr, handler->conf)) {
 495                 ERROR("Failed to add console handler to LXC mainloop.");
 496                 goto out_mainloop_open;
 497         }
 498
 499         if (lxc_cmd_mainloop_add(name, &descr, handler)) {
 500                 ERROR("Failed to add command handler to LXC mainloop.");
 501                 goto out_mainloop_open;
 502         }
 503
 504         TRACE("lxc mainloop is ready");
 505
 506         return lxc_mainloop(&descr, -1);
 507
 508 out_mainloop_open:
 509         lxc_mainloop_close(&descr);
 510
 511 out_sigfd:
 512         close(sigfd);
 513
 514         return -1;
 515 }
 516
 517 void lxc_free_handler(struct lxc_handler *handler)
 518 {
 519         if (handler->conf && handler->conf->maincmd_fd)
 520                 close(handler->conf->maincmd_fd);
 521
 522         if (handler->state_socket_pair[0] >= 0)
 523                 close(handler->state_socket_pair[0]);
 524
 525         if (handler->state_socket_pair[1] >= 0)
 526                 close(handler->state_socket_pair[1]);
 527
 528         if (handler->name)
 529                 free(handler->name);
 530
 531         handler->conf = NULL;
 532         free(handler);
 533 }
 534
 535 struct lxc_handler *lxc_init_handler(const char *name, struct lxc_conf *conf,
 536                                      const char *lxcpath, bool daemonize)
 537 {
 538         int i, ret;
 539         struct lxc_handler *handler;
 540
 541         handler = malloc(sizeof(*handler));
 542         if (!handler) {
 543                 ERROR("failed to allocate memory");
 544                 return NULL;
 545         }
 546
 547         memset(handler, 0, sizeof(*handler));
 548
 549         /* Note that am_unpriv() checks the effective uid. We probably don't
 550          * care if we are real root only if we are running as root so this
 551          * should be fine.
 552          */
 553         handler->am_root = !am_unpriv();
 554         handler->data_sock[0] = handler->data_sock[1] = -1;
 555         handler->conf = conf;
 556         handler->lxcpath = lxcpath;
 557         handler->pinfd = -1;
 558         handler->state_socket_pair[0] = handler->state_socket_pair[1] = -1;
 559         lxc_list_init(&handler->state_clients);
 560
 561         for (i = 0; i < LXC_NS_MAX; i++)
 562                 handler->nsfd[i] = -1;
 563
 564         handler->name = strdup(name);
 565         if (!handler->name) {
 566                 ERROR("failed to allocate memory");
 567                 goto on_error;
 568         }
 569
 570         if (daemonize && !handler->conf->reboot) {
 571                 /* Create socketpair() to synchronize on daemonized startup.
 572                  * When the container reboots we don't need to synchronize again
 573                  * currently so don't open another socketpair().
 574                  */
 575                 ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
 576                                  handler->state_socket_pair);
 577                 if (ret < 0) {
 578                         ERROR("Failed to create anonymous pair of unix sockets");
 579                         goto on_error;
 580                 }
 581                 TRACE("Created anonymous pair {%d,%d} of unix sockets",
 582                       handler->state_socket_pair[0],
 583                       handler->state_socket_pair[1]);
 584         }
 585
 586         if (lxc_cmd_init(name, handler, lxcpath)) {
 587                 ERROR("failed to set up command socket");
 588                 goto on_error;
 589         }
 590
 591         TRACE("unix domain socket %d for command server is ready",
 592               handler->conf->maincmd_fd);
 593
 594         return handler;
 595
 596 on_error:
 597         lxc_free_handler(handler);
 598
 599         return NULL;
 600 }
 601
 602 int lxc_init(const char *name, struct lxc_handler *handler)
 603 {
 604         struct lxc_conf *conf = handler->conf;
 605
 606         lsm_init();
 607         TRACE("initialized LSM");
 608
 609         if (lxc_read_seccomp_config(conf) != 0) {
 610                 ERROR("Failed loading seccomp policy.");
 611                 goto out_close_maincmd_fd;
 612         }
 613         TRACE("read seccomp policy");
 614
 615         /* Begin by setting the state to STARTING. */
 616         if (lxc_set_state(name, handler, STARTING)) {
 617                 ERROR("Failed to set state for container \"%s\" to \"%s\".", name, lxc_state2str(STARTING));
 618                 goto out_close_maincmd_fd;
 619         }
 620         TRACE("set container state to \"STARTING\"");
 621
 622         /* Start of environment variable setup for hooks. */
 623         if (name && setenv("LXC_NAME", name, 1))
 624                 SYSERROR("Failed to set environment variable: LXC_NAME=%s.", name);
 625
 626         if (conf->rcfile && setenv("LXC_CONFIG_FILE", conf->rcfile, 1))
 627                 SYSERROR("Failed to set environment variable: LXC_CONFIG_FILE=%s.", conf->rcfile);
 628
 629         if (conf->rootfs.mount && setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1))
 630                 SYSERROR("Failed to set environment variable: LXC_ROOTFS_MOUNT=%s.", conf->rootfs.mount);
 631
 632         if (conf->rootfs.path && setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1))
 633                 SYSERROR("Failed to set environment variable: LXC_ROOTFS_PATH=%s.", conf->rootfs.path);
 634
 635         if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1))
 636                 SYSERROR("Failed to set environment variable: LXC_CONSOLE=%s.", conf->console.path);
 637
 638         if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1))
 639                 SYSERROR("Failed to set environment variable: LXC_CONSOLE_LOGPATH=%s.", conf->console.log_path);
 640
 641         if (setenv("LXC_CGNS_AWARE", "1", 1))
 642                 SYSERROR("Failed to set environment variable LXC_CGNS_AWARE=1.");
 643
 644         if (setenv("LXC_LOG_LEVEL", lxc_log_priority_to_string(handler->conf->loglevel), 1))
 645                 SYSERROR("Failed to set environment variable LXC_CGNS_AWARE=1.");
 646         /* End of environment variable setup for hooks. */
 647
 648         TRACE("set environment variables");
 649
 650         if (run_lxc_hooks(name, "pre-start", conf, handler->lxcpath, NULL)) {
 651                 ERROR("Failed to run lxc.hook.pre-start for container \"%s\".", name);
 652                 goto out_aborting;
 653         }
 654         TRACE("ran pre-start hooks");
 655
 656         /* The signal fd has to be created before forking otherwise if the child
 657          * process exits before we setup the signal fd, the event will be lost
 658          * and the command will be stuck.
 659          */
 660         handler->sigfd = setup_signal_fd(&handler->oldmask);
 661         if (handler->sigfd < 0) {
 662                 ERROR("Failed to setup SIGCHLD fd handler.");
 663                 goto out_delete_tty;
 664         }
 665         TRACE("set up signal fd");
 666
 667         /* Do this after setting up signals since it might unblock SIGWINCH. */
 668         if (lxc_console_create(conf)) {
 669                 ERROR("Failed to create console for container \"%s\".", name);
 670                 goto out_restore_sigmask;
 671         }
 672         TRACE("created console");
 673
 674         if (lxc_ttys_shift_ids(conf) < 0) {
 675                 ERROR("Failed to shift tty into container.");
 676                 goto out_restore_sigmask;
 677         }
 678         TRACE("shifted tty ids");
 679
 680         INFO("container \"%s\" is initialized", name);
 681         return 0;
 682
 683 out_restore_sigmask:
 684         sigprocmask(SIG_SETMASK, &handler->oldmask, NULL);
 685 out_delete_tty:
 686         lxc_delete_tty(&conf->tty_info);
 687 out_aborting:
 688         lxc_set_state(name, handler, ABORTING);
 689 out_close_maincmd_fd:
 690         close(conf->maincmd_fd);
 691         conf->maincmd_fd = -1;
 692         return -1;
 693 }
 694
 695 void lxc_fini(const char *name, struct lxc_handler *handler)
 696 {
 697         int i, rc;
 698         struct lxc_list *cur, *next;
 699         pid_t self = getpid();
 700         char *namespaces[LXC_NS_MAX + 1];
 701         size_t namespace_count = 0;
 702
 703         /* The STOPPING state is there for future cleanup code which can take
 704          * awhile.
 705          */
 706         lxc_set_state(name, handler, STOPPING);
 707
 708         for (i = 0; i < LXC_NS_MAX; i++) {
 709                 if (handler->nsfd[i] != -1) {
 710                         rc = asprintf(&namespaces[namespace_count], "%s:/proc/%d/fd/%d",
 711                                       ns_info[i].proc_name, self, handler->nsfd[i]);
 712                         if (rc == -1) {
 713                                 SYSERROR("Failed to allocate memory.");
 714                                 break;
 715                         }
 716                         ++namespace_count;
 717                 }
 718         }
 719         namespaces[namespace_count] = NULL;
 720
 721         if (handler->conf->reboot && setenv("LXC_TARGET", "reboot", 1))
 722                 SYSERROR("Failed to set environment variable: LXC_TARGET=reboot.");
 723
 724         if (!handler->conf->reboot && setenv("LXC_TARGET", "stop", 1))
 725                 SYSERROR("Failed to set environment variable: LXC_TARGET=stop.");
 726
 727         if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath, namespaces))
 728                 ERROR("Failed to run lxc.hook.stop for container \"%s\".", name);
 729
 730         while (namespace_count--)
 731                 free(namespaces[namespace_count]);
 732         for (i = 0; i < LXC_NS_MAX; i++) {
 733                 if (handler->nsfd[i] != -1) {
 734                         close(handler->nsfd[i]);
 735                         handler->nsfd[i] = -1;
 736                 }
 737         }
 738
 739         if (handler->netnsfd >= 0) {
 740                 close(handler->netnsfd);
 741                 handler->netnsfd = -1;
 742         }
 743
 744         cgroup_destroy(handler);
 745
 746         lxc_set_state(name, handler, STOPPED);
 747
 748         /* close command socket */
 749         close(handler->conf->maincmd_fd);
 750         handler->conf->maincmd_fd = -1;
 751
 752         if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL)) {
 753                 ERROR("Failed to run lxc.hook.post-stop for container \"%s\".", name);
 754                 if (handler->conf->reboot) {
 755                         WARN("Container will be stopped instead of rebooted.");
 756                         handler->conf->reboot = 0;
 757                         if (setenv("LXC_TARGET", "stop", 1))
 758                                 WARN("Failed to set environment variable: LXC_TARGET=stop.");
 759                 }
 760         }
 761
 762         /* Reset mask set by setup_signal_fd. */
 763         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
 764                 WARN("Failed to restore signal mask.");
 765
 766         lxc_console_delete(&handler->conf->console);
 767         lxc_delete_tty(&handler->conf->tty_info);
 768
 769         /* The command socket is now closed, no more state clients can register
 770          * themselves from now on. So free the list of state clients.
 771          */
 772         lxc_list_for_each_safe(cur, &handler->state_clients, next) {
 773                 struct state_client *client = cur->elem;
 774                 /* close state client socket */
 775                 close(client->clientfd);
 776                 lxc_list_del(cur);
 777                 free(cur->elem);
 778                 free(cur);
 779         }
 780
 781         if (handler->data_sock[0] != -1) {
 782                 close(handler->data_sock[0]);
 783                 close(handler->data_sock[1]);
 784         }
 785
 786         if (handler->conf->ephemeral == 1 && handler->conf->reboot != 1)
 787                 lxc_destroy_container_on_signal(handler, name);
 788
 789         free(handler->name);
 790         free(handler);
 791 }
 792
 793 void lxc_abort(const char *name, struct lxc_handler *handler)
 794 {
 795         int ret, status;
 796
 797         lxc_set_state(name, handler, ABORTING);
 798         if (handler->pid > 0)
 799                 kill(handler->pid, SIGKILL);
 800         while ((ret = waitpid(-1, &status, 0)) > 0) {
 801                 ;
 802         }
 803 }
 804
 805 static int do_start(void *data)
 806 {
 807         struct lxc_list *iterator;
 808         struct lxc_handler *handler = data;
 809         int devnull_fd = -1, ret;
 810         char path[PATH_MAX];
 811
 812         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL)) {
 813                 SYSERROR("Failed to set signal mask.");
 814                 return -1;
 815         }
 816
 817         /* This prctl must be before the synchro, so if the parent dies before
 818          * we set the parent death signal, we will detect its death with the
 819          * synchro right after, otherwise we have a window where the parent can
 820          * exit before we set the pdeath signal leading to a unsupervized
 821          * container.
 822          */
 823         if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0)) {
 824                 SYSERROR("Failed to set PR_SET_PDEATHSIG to SIGKILL.");
 825                 return -1;
 826         }
 827
 828         lxc_sync_fini_parent(handler);
 829
 830         /* Don't leak the pinfd to the container. */
 831         if (handler->pinfd >= 0) {
 832                 close(handler->pinfd);
 833         }
 834
 835         if (lxc_sync_wait_parent(handler, LXC_SYNC_STARTUP))
 836                 return -1;
 837
 838         /* Unshare CLONE_NEWNET after CLONE_NEWUSER. See
 839          * https://github.com/lxc/lxd/issues/1978.
 840          */
 841         if ((handler->clone_flags & (CLONE_NEWNET | CLONE_NEWUSER)) ==
 842             (CLONE_NEWNET | CLONE_NEWUSER)) {
 843                 ret = unshare(CLONE_NEWNET);
 844                 if (ret < 0) {
 845                         SYSERROR("Failed to unshare CLONE_NEWNET.");
 846                         goto out_warn_father;
 847                 }
 848                 INFO("Unshared CLONE_NEWNET.");
 849         }
 850
 851         /* Tell the parent task it can begin to configure the container and wait
 852          * for it to finish.
 853          */
 854         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
 855                 return -1;
 856
 857         if (lxc_network_recv_veth_names_from_parent(handler) < 0) {
 858                 ERROR("Failed to receive veth names from parent");
 859                 goto out_warn_father;
 860         }
 861
 862         /* If we are in a new user namespace, become root there to have
 863          * privilege over our namespace.
 864          */
 865         if (!lxc_list_empty(&handler->conf->id_map)) {
 866                 if (lxc_switch_uid_gid(0, 0) < 0)
 867                         goto out_warn_father;
 868
 869                 /* Drop groups only after we switched to a valid gid in the new
 870                  * user namespace.
 871                  */
 872                 if (lxc_setgroups(0, NULL) < 0)
 873                         goto out_warn_father;
 874         }
 875
 876         if (access(handler->lxcpath, X_OK)) {
 877                 print_top_failing_dir(handler->lxcpath);
 878                 goto out_warn_father;
 879         }
 880
 881         ret = snprintf(path, sizeof(path), "%s/dev/null", handler->conf->rootfs.mount);
 882         if (ret < 0 || ret >= sizeof(path))
 883                 goto out_warn_father;
 884
 885         /* In order to checkpoint restore, we need to have everything in the
 886          * same mount namespace. However, some containers may not have a
 887          * reasonable /dev (in particular, they may not have /dev/null), so we
 888          * can't set init's std fds to /dev/null by opening it from inside the
 889          * container.
 890          *
 891          * If that's the case, fall back to using the host's /dev/null. This
 892          * means that migration won't work, but at least we won't spew output
 893          * where it isn't wanted.
 894          */
 895         if (handler->backgrounded && !handler->conf->autodev && access(path, F_OK) < 0) {
 896                 devnull_fd = open_devnull();
 897
 898                 if (devnull_fd < 0)
 899                         goto out_warn_father;
 900                 WARN("Using /dev/null from the host for container init's "
 901                      "standard file descriptors. Migration will not work.");
 902         }
 903
 904         /* Ask father to setup cgroups and wait for him to finish. */
 905         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
 906                 goto out_error;
 907
 908         /* Unshare cgroup namespace after we have setup our cgroups. If we do it
 909          * earlier we end up with a wrong view of /proc/self/cgroup. For
 910          * example, assume we unshare(CLONE_NEWCGROUP) first, and then create
 911          * the cgroup for the container, say /sys/fs/cgroup/cpuset/lxc/c, then
 912          * /proc/self/cgroup would show us:
 913          *
 914          *      8:cpuset:/lxc/c
 915          *
 916          * whereas it should actually show
 917          *
 918          *      8:cpuset:/
 919          */
 920         if (cgns_supported()) {
 921                 if (unshare(CLONE_NEWCGROUP) < 0) {
 922                         INFO("Failed to unshare CLONE_NEWCGROUP.");
 923                         goto out_warn_father;
 924                 }
 925                 INFO("Unshared CLONE_NEWCGROUP.");
 926         }
 927
 928         /* Add the requested environment variables to the current environment to
 929          * allow them to be used by the various hooks, such as the start hook
 930          * above.
 931          */
 932         lxc_list_for_each(iterator, &handler->conf->environment) {
 933                 if (putenv((char *)iterator->elem)) {
 934                         SYSERROR("Failed to set environment variable: %s.", (char *)iterator->elem);
 935                         goto out_warn_father;
 936                 }
 937         }
 938
 939         /* Setup the container, ip, names, utsname, ... */
 940         ret = lxc_setup(handler);
 941         close(handler->data_sock[0]);
 942         close(handler->data_sock[1]);
 943         if (ret < 0) {
 944                 ERROR("Failed to setup container \"%s\".", handler->name);
 945                 goto out_warn_father;
 946         }
 947
 948         /* Set the label to change to when we exec(2) the container's init. */
 949         if (lsm_process_label_set(NULL, handler->conf, 1, 1) < 0)
 950                 goto out_warn_father;
 951
 952         /* Set PR_SET_NO_NEW_PRIVS after we changed the lsm label. If we do it
 953          * before we aren't allowed anymore.
 954          */
 955         if (handler->conf->no_new_privs) {
 956                 if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
 957                         SYSERROR("Could not set PR_SET_NO_NEW_PRIVS to block execve() gainable privileges.");
 958                         goto out_warn_father;
 959                 }
 960                 DEBUG("Set PR_SET_NO_NEW_PRIVS to block execve() gainable privileges.");
 961         }
 962
 963         /* Some init's such as busybox will set sane tty settings on stdin,
 964          * stdout, stderr which it thinks is the console. We already set them
 965          * the way we wanted on the real terminal, and we want init to do its
 966          * setup on its console ie. the pty allocated in lxc_console_create() so
 967          * make sure that that pty is stdin,stdout,stderr.
 968          */
 969          if (handler->conf->console.slave >= 0)
 970                  if (set_stdfds(handler->conf->console.slave) < 0) {
 971                         ERROR("Failed to redirect std{in,out,err} to pty file "
 972                               "descriptor %d",
 973                               handler->conf->console.slave);
 974                         goto out_warn_father;
 975                  }
 976
 977         /* If we mounted a temporary proc, then unmount it now. */
 978         tmp_proc_unmount(handler->conf);
 979
 980         if (lxc_seccomp_load(handler->conf) != 0)
 981                 goto out_warn_father;
 982
 983         if (run_lxc_hooks(handler->name, "start", handler->conf, handler->lxcpath, NULL)) {
 984                 ERROR("Failed to run lxc.hook.start for container \"%s\".", handler->name);
 985                 goto out_warn_father;
 986         }
 987
 988         close(handler->sigfd);
 989
 990         if (devnull_fd < 0) {
 991                 devnull_fd = open_devnull();
 992
 993                 if (devnull_fd < 0)
 994                         goto out_warn_father;
 995         }
 996
 997         if (handler->conf->console.slave < 0 && handler->backgrounded)
 998                 if (set_stdfds(devnull_fd) < 0) {
 999                         ERROR("Failed to redirect std{in,out,err} to "
1000                               "\"/dev/null\"");
1001                         goto out_warn_father;
1002                 }
1003
1004         if (devnull_fd >= 0) {
1005                 close(devnull_fd);
1006                 devnull_fd = -1;
1007         }
1008
1009         setsid();
1010
1011         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP_LIMITS))
1012                 goto out_warn_father;
1013
1014         /* Reset the environment variables the user requested in a clear
1015          * environment.
1016          */
1017         if (clearenv()) {
1018                 SYSERROR("Failed to clear environment.");
1019                 /* Don't error out though. */
1020         }
1021
1022         lxc_list_for_each(iterator, &handler->conf->environment) {
1023                 if (putenv((char *)iterator->elem)) {
1024                         SYSERROR("Failed to set environment variable: %s.", (char *)iterator->elem);
1025                         goto out_warn_father;
1026                 }
1027         }
1028
1029         if (putenv("container=lxc")) {
1030                 SYSERROR("Failed to set environment variable: container=lxc.");
1031                 goto out_warn_father;
1032         }
1033
1034         if (handler->conf->pty_names) {
1035                 if (putenv(handler->conf->pty_names)) {
1036                         SYSERROR("Failed to set environment variable for container ptys.");
1037                         goto out_warn_father;
1038                 }
1039         }
1040
1041         /* The container has been setup. We can now switch to an unprivileged
1042          * uid/gid.
1043          */
1044         if (handler->conf->is_execute) {
1045                 bool have_cap_setgid;
1046                 uid_t new_uid = handler->conf->init_uid;
1047                 gid_t new_gid = handler->conf->init_gid;
1048
1049                 /* If we are in a new user namespace we already dropped all
1050                  * groups when we switched to root in the new user namespace
1051                  * further above. Only drop groups if we can, so ensure that we
1052                  * have necessary privilege.
1053                  */
1054                 #if HAVE_LIBCAP
1055                 have_cap_setgid = lxc_proc_cap_is_set(CAP_SETGID, CAP_EFFECTIVE);
1056                 #else
1057                 have_cap_setgid = false;
1058                 #endif
1059                 if (lxc_list_empty(&handler->conf->id_map) && have_cap_setgid) {
1060                         if (lxc_setgroups(0, NULL) < 0)
1061                                 goto out_warn_father;
1062                 }
1063
1064                 if (lxc_switch_uid_gid(new_uid, new_gid) < 0)
1065                         goto out_warn_father;
1066         }
1067
1068         /* After this call, we are in error because this ops should not return
1069          * as it execs.
1070          */
1071         handler->ops->start(handler, handler->data);
1072
1073 out_warn_father:
1074         /* We want the parent to know something went wrong, so we return a
1075          * special error code.
1076          */
1077         lxc_sync_wake_parent(handler, LXC_SYNC_ERROR);
1078
1079 out_error:
1080         if (devnull_fd >= 0)
1081                 close(devnull_fd);
1082
1083         return -1;
1084 }
1085
1086 static int lxc_recv_ttys_from_child(struct lxc_handler *handler)
1087 {
1088         int i;
1089         struct lxc_pty_info *pty_info;
1090         int ret = -1;
1091         int sock = handler->data_sock[1];
1092         struct lxc_conf *conf = handler->conf;
1093         struct lxc_tty_info *tty_info = &conf->tty_info;
1094
1095         if (!conf->tty)
1096                 return 0;
1097
1098         tty_info->pty_info = malloc(sizeof(*tty_info->pty_info) * conf->tty);
1099         if (!tty_info->pty_info)
1100                 return -1;
1101
1102         for (i = 0; i < conf->tty; i++) {
1103                 int ttyfds[2];
1104
1105                 ret = lxc_abstract_unix_recv_fds(sock, ttyfds, 2, NULL, 0);
1106                 if (ret < 0)
1107                         break;
1108
1109                 pty_info = &tty_info->pty_info[i];
1110                 pty_info->busy = 0;
1111                 pty_info->master = ttyfds[0];
1112                 pty_info->slave = ttyfds[1];
1113                 TRACE("Received pty with master fd %d and slave fd %d from "
1114                       "parent", pty_info->master, pty_info->slave);
1115         }
1116         if (ret < 0)
1117                 ERROR("Failed to receive %d ttys from child: %s", conf->tty,
1118                       strerror(errno));
1119         else
1120                 TRACE("Received %d ttys from child", conf->tty);
1121
1122         tty_info->nbtty = conf->tty;
1123
1124         return ret;
1125 }
1126
1127 void resolve_clone_flags(struct lxc_handler *handler)
1128 {
1129         handler->clone_flags = CLONE_NEWNS;
1130
1131         if (!lxc_list_empty(&handler->conf->id_map))
1132                 handler->clone_flags |= CLONE_NEWUSER;
1133
1134         if (handler->conf->inherit_ns_fd[LXC_NS_NET] == -1) {
1135                 if (!lxc_requests_empty_network(handler))
1136                         handler->clone_flags |= CLONE_NEWNET;
1137         } else {
1138                 INFO("Inheriting a NET namespace.");
1139         }
1140
1141         if (handler->conf->inherit_ns_fd[LXC_NS_IPC] == -1)
1142                 handler->clone_flags |= CLONE_NEWIPC;
1143         else
1144                 INFO("Inheriting an IPC namespace.");
1145
1146         if (handler->conf->inherit_ns_fd[LXC_NS_UTS] == -1)
1147                 handler->clone_flags |= CLONE_NEWUTS;
1148         else
1149                 INFO("Inheriting a UTS namespace.");
1150
1151         if (handler->conf->inherit_ns_fd[LXC_NS_PID] == -1)
1152                 handler->clone_flags |= CLONE_NEWPID;
1153         else
1154                 INFO("Inheriting a PID namespace.");
1155 }
1156
1157 /* lxc_spawn() performs crucial setup tasks and clone()s the new process which
1158  * exec()s the requested container binary.
1159  * Note that lxc_spawn() runs in the parent namespaces. Any operations performed
1160  * right here should be double checked if they'd pose a security risk. (For
1161  * example, any {u}mount() operations performed here will be reflected on the
1162  * host!)
1163  */
1164 static int lxc_spawn(struct lxc_handler *handler)
1165 {
1166         int i, flags, ret;
1167         const char *name = handler->name;
1168         bool wants_to_map_ids;
1169         int saved_ns_fd[LXC_NS_MAX];
1170         struct lxc_list *id_map;
1171         int preserve_mask = 0;
1172         bool cgroups_connected = false;
1173
1174         id_map = &handler->conf->id_map;
1175         wants_to_map_ids = !lxc_list_empty(id_map);
1176
1177         for (i = 0; i < LXC_NS_MAX; i++)
1178                 if (handler->conf->inherit_ns_fd[i] != -1)
1179                         preserve_mask |= ns_info[i].clone_flag;
1180
1181         if (lxc_sync_init(handler))
1182                 return -1;
1183
1184         ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
1185                          handler->data_sock);
1186         if (ret < 0) {
1187                 lxc_sync_fini(handler);
1188                 return -1;
1189         }
1190
1191         resolve_clone_flags(handler);
1192
1193         if (handler->clone_flags & CLONE_NEWNET) {
1194                 if (!lxc_list_empty(&handler->conf->network)) {
1195
1196                         /* Find gateway addresses from the link device, which is
1197                          * no longer accessible inside the container. Do this
1198                          * before creating network interfaces, since goto
1199                          * out_delete_net does not work before lxc_clone.
1200                          */
1201                         if (lxc_find_gateway_addresses(handler)) {
1202                                 ERROR("Failed to find gateway addresses.");
1203                                 lxc_sync_fini(handler);
1204                                 return -1;
1205                         }
1206
1207                         /* That should be done before the clone because we will
1208                          * fill the netdev index and use them in the child.
1209                          */
1210                         if (lxc_create_network_priv(handler)) {
1211                                 ERROR("Failed to create the network.");
1212                                 lxc_sync_fini(handler);
1213                                 return -1;
1214                         }
1215                 }
1216         }
1217
1218         if (!cgroup_init(handler)) {
1219                 ERROR("Failed initializing cgroup support.");
1220                 goto out_delete_net;
1221         }
1222
1223         cgroups_connected = true;
1224
1225         if (!cgroup_create(handler)) {
1226                 ERROR("Failed creating cgroups.");
1227                 goto out_delete_net;
1228         }
1229
1230         /* If the rootfs is not a blockdev, prevent the container from marking
1231          * it readonly.
1232          * If the container is unprivileged then skip rootfs pinning.
1233          */
1234         if (!wants_to_map_ids) {
1235                 handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
1236                 if (handler->pinfd == -1)
1237                         INFO("Failed to pin the rootfs for container \"%s\".", handler->name);
1238         }
1239
1240         if (!preserve_ns(saved_ns_fd, preserve_mask, getpid()))
1241                 goto out_delete_net;
1242
1243         if (attach_ns(handler->conf->inherit_ns_fd) < 0)
1244                 goto out_delete_net;
1245
1246         /* Create a process in a new set of namespaces. */
1247         flags = handler->clone_flags;
1248         if (handler->clone_flags & CLONE_NEWUSER) {
1249                 /* If CLONE_NEWUSER and CLONE_NEWNET was requested, we need to
1250                  * clone a new user namespace first and only later unshare our
1251                  * network namespace to ensure that network devices ownership is
1252                  * set up correctly.
1253                  */
1254                 flags &= ~CLONE_NEWNET;
1255         }
1256         handler->pid = lxc_clone(do_start, handler, flags);
1257         if (handler->pid < 0) {
1258                 SYSERROR("Failed to clone a new set of namespaces.");
1259                 goto out_delete_net;
1260         }
1261
1262         for (i = 0; i < LXC_NS_MAX; i++)
1263                 if (flags & ns_info[i].clone_flag)
1264                         INFO("Cloned %s.", ns_info[i].flag_name);
1265
1266         if (!preserve_ns(handler->nsfd, handler->clone_flags | preserve_mask, handler->pid))
1267                 INFO("Failed to preserve namespace for lxc.hook.stop.");
1268
1269         if (attach_ns(saved_ns_fd))
1270                 WARN("Failed to restore saved namespaces.");
1271
1272         lxc_sync_fini_child(handler);
1273
1274         /* Map the container uids. The container became an invalid userid the
1275          * moment it was cloned with CLONE_NEWUSER. This call doesn't change
1276          * anything immediately, but allows the container to setuid(0) (0 being
1277          * mapped to something else on the host.) later to become a valid uid
1278          * again.
1279          */
1280         if (wants_to_map_ids && lxc_map_ids(id_map, handler->pid)) {
1281                 ERROR("Failed to set up id mapping.");
1282                 goto out_delete_net;
1283         }
1284
1285         if (lxc_sync_wake_child(handler, LXC_SYNC_STARTUP))
1286                 goto out_delete_net;
1287
1288         if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE))
1289                 goto out_delete_net;
1290
1291         if (!cgroup_create_legacy(handler)) {
1292                 ERROR("Failed to setup legacy cgroups for container \"%s\".", name);
1293                 goto out_delete_net;
1294         }
1295         if (!cgroup_setup_limits(handler, false)) {
1296                 ERROR("Failed to setup cgroup limits for container \"%s\".", name);
1297                 goto out_delete_net;
1298         }
1299
1300         if (!cgroup_enter(handler))
1301                 goto out_delete_net;
1302
1303         if (!cgroup_chown(handler))
1304                 goto out_delete_net;
1305
1306         handler->netnsfd = lxc_preserve_ns(handler->pid, "net");
1307         if (handler->netnsfd < 0) {
1308                 ERROR("Failed to preserve network namespace");
1309                 goto out_delete_net;
1310         }
1311
1312         /* Create the network configuration. */
1313         if (handler->clone_flags & CLONE_NEWNET) {
1314                 if (lxc_network_move_created_netdev_priv(handler->lxcpath,
1315                                                          handler->name,
1316                                                          &handler->conf->network,
1317                                                          handler->pid)) {
1318                         ERROR("Failed to create the configured network.");
1319                         goto out_delete_net;
1320                 }
1321
1322                 if (lxc_create_network_unpriv(handler->lxcpath, handler->name,
1323                                               &handler->conf->network,
1324                                               handler->pid)) {
1325                         ERROR("Failed to create the configured network.");
1326                         goto out_delete_net;
1327                 }
1328         }
1329
1330         if (lxc_network_send_veth_names_to_child(handler) < 0) {
1331                 ERROR("Failed to send veth names to child");
1332                 goto out_delete_net;
1333         }
1334
1335         /* Tell the child to continue its initialization. We'll get
1336          * LXC_SYNC_CGROUP when it is ready for us to setup cgroups.
1337          */
1338         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
1339                 goto out_delete_net;
1340
1341         if (!lxc_list_empty(&handler->conf->limits) && setup_resource_limits(&handler->conf->limits, handler->pid)) {
1342                 ERROR("failed to setup resource limits for '%s'", name);
1343                 goto out_delete_net;
1344         }
1345
1346         if (lxc_sync_barrier_child(handler, LXC_SYNC_CGROUP_UNSHARE))
1347                 goto out_delete_net;
1348
1349         if (!cgroup_setup_limits(handler, true)) {
1350                 ERROR("Failed to setup the devices cgroup for container \"%s\".", name);
1351                 goto out_delete_net;
1352         }
1353         TRACE("Set up cgroup device limits");
1354
1355         cgroup_disconnect();
1356         cgroups_connected = false;
1357
1358         /* Tell the child to complete its initialization and wait for it to exec
1359          * or return an error. (The child will never return
1360          * LXC_SYNC_POST_CGROUP+1. It will either close the sync pipe, causing
1361          * lxc_sync_barrier_child to return success, or return a different
1362          * value, causing us to error out).
1363          */
1364         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
1365                 return -1;
1366
1367         if (lxc_network_recv_name_and_ifindex_from_child(handler) < 0) {
1368                 ERROR("Failed to receive names and ifindices for network "
1369                       "devices from child");
1370                 goto out_delete_net;
1371         }
1372
1373         /* Now all networks are created, network devices are moved into place,
1374          * and the correct names and ifindeces in the respective namespaces have
1375          * been recorded. The corresponding structs have now all been filled. So
1376          * log them for debugging purposes.
1377          */
1378         lxc_log_configured_netdevs(handler->conf);
1379
1380         /* Read tty fds allocated by child. */
1381         if (lxc_recv_ttys_from_child(handler) < 0) {
1382                 ERROR("Failed to receive tty info from child process.");
1383                 goto out_delete_net;
1384         }
1385
1386         if (handler->ops->post_start(handler, handler->data))
1387                 goto out_abort;
1388
1389         if (lxc_set_state(name, handler, RUNNING)) {
1390                 ERROR("Failed to set state for container \"%s\" to \"%s\".", name,
1391                       lxc_state2str(RUNNING));
1392                 goto out_abort;
1393         }
1394
1395         lxc_sync_fini(handler);
1396
1397         return 0;
1398
1399 out_delete_net:
1400         if (cgroups_connected)
1401                 cgroup_disconnect();
1402
1403         if (handler->clone_flags & CLONE_NEWNET) {
1404                 DEBUG("Tearing down network devices");
1405                 if (!lxc_delete_network_priv(handler))
1406                         DEBUG("Failed tearing down network devices");
1407
1408                 if (!lxc_delete_network_unpriv(handler))
1409                         DEBUG("Failed tearing down network devices");
1410         }
1411
1412 out_abort:
1413         lxc_abort(name, handler);
1414         lxc_sync_fini(handler);
1415         if (handler->pinfd >= 0) {
1416                 close(handler->pinfd);
1417                 handler->pinfd = -1;
1418         }
1419
1420         if (handler->netnsfd >= 0) {
1421                 close(handler->netnsfd);
1422                 handler->netnsfd = -1;
1423         }
1424
1425         return -1;
1426 }
1427
1428 int __lxc_start(const char *name, struct lxc_handler *handler,
1429                 struct lxc_operations* ops, void *data, const char *lxcpath,
1430                 bool backgrounded)
1431 {
1432         int status;
1433         int err = -1;
1434         struct lxc_conf *conf = handler->conf;
1435
1436         if (lxc_init(name, handler) < 0) {
1437                 ERROR("Failed to initialize container \"%s\".", name);
1438                 return -1;
1439         }
1440         handler->ops = ops;
1441         handler->data = data;
1442         handler->backgrounded = backgrounded;
1443         handler->netnsfd = -1;
1444
1445         if (!attach_block_device(handler->conf)) {
1446                 ERROR("Failed to attach block device.");
1447                 goto out_fini_nonet;
1448         }
1449
1450         if (geteuid() == 0 && !lxc_list_empty(&conf->id_map)) {
1451                 /* If the backing store is a device, mount it here and now. */
1452                 if (rootfs_is_blockdev(conf)) {
1453                         if (unshare(CLONE_NEWNS) < 0) {
1454                                 ERROR("Failed to unshare CLONE_NEWNS.");
1455                                 goto out_fini_nonet;
1456                         }
1457                         INFO("Unshared CLONE_NEWNS.");
1458
1459                         remount_all_slave();
1460                         if (do_rootfs_setup(conf, name, lxcpath) < 0) {
1461                                 ERROR("Error setting up rootfs mount as root before spawn.");
1462                                 goto out_fini_nonet;
1463                         }
1464                         INFO("Set up container rootfs as host root.");
1465                 }
1466         }
1467
1468         err = lxc_spawn(handler);
1469         if (err) {
1470                 ERROR("Failed to spawn container \"%s\".", name);
1471                 goto out_detach_blockdev;
1472         }
1473
1474         handler->conf->reboot = 0;
1475
1476         err = lxc_poll(name, handler);
1477         if (err) {
1478                 ERROR("LXC mainloop exited with error: %d.", err);
1479                 goto out_abort;
1480         }
1481
1482         while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
1483                 continue;
1484
1485         /* If the child process exited but was not signaled, it didn't call
1486          * reboot. This should mean it was an lxc-execute which simply exited.
1487          * In any case, treat it as a 'halt'.
1488          */
1489         if (WIFSIGNALED(status)) {
1490                 switch(WTERMSIG(status)) {
1491                 case SIGINT: /* halt */
1492                         DEBUG("Container \"%s\" is halting.", name);
1493                         break;
1494                 case SIGHUP: /* reboot */
1495                         DEBUG("Container \"%s\" is rebooting.", name);
1496                         handler->conf->reboot = 1;
1497                         break;
1498                 case SIGSYS: /* seccomp */
1499                         DEBUG("Container \"%s\" violated its seccomp policy.", name);
1500                         break;
1501                 default:
1502                         DEBUG("Unknown exit status for container \"%s\" init %d.", name, WTERMSIG(status));
1503                         break;
1504                 }
1505         }
1506
1507         err = lxc_restore_phys_nics_to_netns(handler);
1508         if (err < 0)
1509                 ERROR("Failed to move physical network devices back to parent "
1510                       "network namespace");
1511
1512         if (handler->pinfd >= 0) {
1513                 close(handler->pinfd);
1514                 handler->pinfd = -1;
1515         }
1516
1517         lxc_monitor_send_exit_code(name, status, handler->lxcpath);
1518         err =  lxc_error_set_and_log(handler->pid, status);
1519
1520 out_fini:
1521         DEBUG("Tearing down network devices");
1522         if (!lxc_delete_network_priv(handler))
1523                 DEBUG("Failed tearing down network devices");
1524
1525         if (!lxc_delete_network_unpriv(handler))
1526                 DEBUG("Failed tearing down network devices");
1527
1528         if (handler->netnsfd >= 0) {
1529                 close(handler->netnsfd);
1530                 handler->netnsfd = -1;
1531         }
1532
1533 out_detach_blockdev:
1534         detach_block_device(handler->conf);
1535
1536 out_fini_nonet:
1537         lxc_fini(name, handler);
1538         return err;
1539
1540 out_abort:
1541         lxc_abort(name, handler);
1542         goto out_fini;
1543 }
1544
1545 struct start_args {
1546         char *const *argv;
1547 };
1548
1549 static int start(struct lxc_handler *handler, void* data)
1550 {
1551         struct start_args *arg = data;
1552
1553         NOTICE("Exec'ing \"%s\".", arg->argv[0]);
1554
1555         execvp(arg->argv[0], arg->argv);
1556         SYSERROR("Failed to exec \"%s\".", arg->argv[0]);
1557         return 0;
1558 }
1559
1560 static int post_start(struct lxc_handler *handler, void* data)
1561 {
1562         struct start_args *arg = data;
1563
1564         NOTICE("Started \"%s\" with pid \"%d\".", arg->argv[0], handler->pid);
1565         return 0;
1566 }
1567
1568 static struct lxc_operations start_ops = {
1569         .start = start,
1570         .post_start = post_start
1571 };
1572
1573 int lxc_start(const char *name, char *const argv[], struct lxc_handler *handler,
1574               const char *lxcpath, bool backgrounded)
1575 {
1576         struct start_args start_arg = {
1577                 .argv = argv,
1578         };
1579
1580         return __lxc_start(name, handler, &start_ops, &start_arg, lxcpath, backgrounded);
1581 }
1582
1583 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
1584                                             const char *name)
1585 {
1586         char destroy[MAXPATHLEN];
1587         bool bret = true;
1588         int ret = 0;
1589         struct lxc_container *c;
1590         if (handler->conf->rootfs.path && handler->conf->rootfs.mount) {
1591                 bret = do_destroy_container(handler);
1592                 if (!bret) {
1593                         ERROR("Error destroying rootfs for container \"%s\".", name);
1594                         return;
1595                 }
1596         }
1597         INFO("Destroyed rootfs for container \"%s\".", name);
1598
1599         ret = snprintf(destroy, MAXPATHLEN, "%s/%s", handler->lxcpath, name);
1600         if (ret < 0 || ret >= MAXPATHLEN) {
1601                 ERROR("Error destroying directory for container \"%s\".", name);
1602                 return;
1603         }
1604
1605         c = lxc_container_new(name, handler->lxcpath);
1606         if (c) {
1607                 if (container_disk_lock(c)) {
1608                         INFO("Could not update lxc_snapshots file.");
1609                         lxc_container_put(c);
1610                 } else {
1611                         mod_all_rdeps(c, false);
1612                         container_disk_unlock(c);
1613                         lxc_container_put(c);
1614                 }
1615         }
1616
1617         if (!handler->am_root)
1618                 ret = userns_exec_full(handler->conf, lxc_rmdir_onedev_wrapper,
1619                                        destroy, "lxc_rmdir_onedev_wrapper");
1620         else
1621                 ret = lxc_rmdir_onedev(destroy, NULL);
1622
1623         if (ret < 0) {
1624                 ERROR("Error destroying directory for container \"%s\".", name);
1625                 return;
1626         }
1627         INFO("Destroyed directory for container \"%s\".", name);
1628 }
1629
1630 static int lxc_rmdir_onedev_wrapper(void *data)
1631 {
1632         char *arg = (char *) data;
1633         return lxc_rmdir_onedev(arg, NULL);
1634 }
1635
1636 static bool do_destroy_container(struct lxc_handler *handler) {
1637         int ret;
1638
1639         if (!handler->am_root) {
1640                 ret = userns_exec_full(handler->conf, storage_destroy_wrapper,
1641                                        handler->conf, "storage_destroy_wrapper");
1642                 if (ret < 0)
1643                         return false;
1644
1645                 return true;
1646         }
1647
1648         return storage_destroy(handler->conf);
1649 }