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  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #define _GNU_SOURCE
  25 #include "config.h"
  26
  27 #include <alloca.h>
  28 #include <dirent.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <grp.h>
  32 #include <poll.h>
  33 #include <signal.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38 #include <sys/file.h>
  39 #include <sys/mount.h>
  40 #include <sys/param.h>
  41 #include <sys/prctl.h>
  42 #include <sys/socket.h>
  43 #include <sys/stat.h>
  44 #include <sys/syscall.h>
  45 #include <sys/types.h>
  46 #include <sys/un.h>
  47 #include <sys/wait.h>
  48
  49 #if HAVE_LIBCAP
  50 #include <sys/capability.h>
  51 #endif
  52
  53 #ifndef HAVE_DECL_PR_CAPBSET_DROP
  54 #define PR_CAPBSET_DROP 24
  55 #endif
  56
  57 #ifndef HAVE_DECL_PR_SET_NO_NEW_PRIVS
  58 #define PR_SET_NO_NEW_PRIVS 38
  59 #endif
  60
  61 #ifndef HAVE_DECL_PR_GET_NO_NEW_PRIVS
  62 #define PR_GET_NO_NEW_PRIVS 39
  63 #endif
  64
  65 #include "af_unix.h"
  66 #include "caps.h"
  67 #include "cgroup.h"
  68 #include "commands.h"
  69 #include "commands_utils.h"
  70 #include "conf.h"
  71 #include "confile_utils.h"
  72 #include "console.h"
  73 #include "error.h"
  74 #include "log.h"
  75 #include "lxccontainer.h"
  76 #include "lxclock.h"
  77 #include "lxcseccomp.h"
  78 #include "mainloop.h"
  79 #include "monitor.h"
  80 #include "namespace.h"
  81 #include "network.h"
  82 #include "start.h"
  83 #include "storage.h"
  84 #include "storage_utils.h"
  85 #include "sync.h"
  86 #include "utils.h"
  87 #include "lsm/lsm.h"
  88
  89 lxc_log_define(lxc_start, lxc);
  90
  91 extern void mod_all_rdeps(struct lxc_container *c, bool inc);
  92 static bool do_destroy_container(struct lxc_handler *handler);
  93 static int lxc_rmdir_onedev_wrapper(void *data);
  94 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
  95                                             const char *name);
  96
  97 static void print_top_failing_dir(const char *path)
  98 {
  99         size_t len = strlen(path);
 100         char *copy = alloca(len + 1), *p, *e, saved;
 101         strcpy(copy, path);
 102
 103         p = copy;
 104         e = copy + len;
 105         while (p < e) {
 106                 while (p < e && *p == '/')
 107                         p++;
 108                 while (p < e && *p != '/')
 109                         p++;
 110                 saved = *p;
 111                 *p = '\0';
 112                 if (access(copy, X_OK)) {
 113                         SYSERROR("Could not access %s. Please grant it x "
 114                                  "access, or add an ACL for the container "
 115                                  "root.", copy);
 116                         return;
 117                 }
 118                 *p = saved;
 119         }
 120 }
 121
 122 static void close_ns(int ns_fd[LXC_NS_MAX])
 123 {
 124         int i;
 125
 126         for (i = 0; i < LXC_NS_MAX; i++) {
 127                 if (ns_fd[i] > -1) {
 128                         close(ns_fd[i]);
 129                         ns_fd[i] = -1;
 130                 }
 131         }
 132 }
 133
 134 /* preserve_ns: open /proc/@pid/ns/@ns for each namespace specified
 135  * in clone_flags.
 136  * Return true on success, false on failure.
 137  */
 138 static bool preserve_ns(int ns_fd[LXC_NS_MAX], int clone_flags, pid_t pid)
 139 {
 140         int i, ret;
 141
 142         for (i = 0; i < LXC_NS_MAX; i++)
 143                 ns_fd[i] = -1;
 144
 145         ret = lxc_preserve_ns(pid, "");
 146         if (ret < 0) {
 147                 SYSERROR("Kernel does not support attaching to namespaces.");
 148                 return false;
 149         } else {
 150                 close(ret);
 151         }
 152
 153         for (i = 0; i < LXC_NS_MAX; i++) {
 154                 if ((clone_flags & ns_info[i].clone_flag) == 0)
 155                         continue;
 156                 ns_fd[i] = lxc_preserve_ns(pid, ns_info[i].proc_name);
 157                 if (ns_fd[i] < 0)
 158                         goto error;
 159         }
 160
 161         return true;
 162
 163 error:
 164         if (errno == ENOENT)
 165                 SYSERROR("Kernel does not support attaching to %s namespaces.", ns_info[i].proc_name);
 166         else
 167                 SYSERROR("Failed to open file descriptor for %s namespace: %s.", ns_info[i].proc_name, strerror(errno));
 168         close_ns(ns_fd);
 169         return false;
 170 }
 171
 172 static int attach_ns(const int ns_fd[LXC_NS_MAX]) {
 173         int i;
 174
 175         for (i = 0; i < LXC_NS_MAX; i++) {
 176                 if (ns_fd[i] < 0)
 177                         continue;
 178
 179                 if (setns(ns_fd[i], 0) != 0)
 180                         goto error;
 181         }
 182         return 0;
 183
 184 error:
 185         SYSERROR("Failed to attach %s namespace.", ns_info[i].proc_name);
 186         return -1;
 187 }
 188
 189 static int match_fd(int fd)
 190 {
 191         return (fd == 0 || fd == 1 || fd == 2);
 192 }
 193
 194 int lxc_check_inherited(struct lxc_conf *conf, bool closeall,
 195                         int *fds_to_ignore, size_t len_fds)
 196 {
 197         struct dirent *direntp;
 198         int fd, fddir;
 199         size_t i;
 200         DIR *dir;
 201
 202         if (conf && conf->close_all_fds)
 203                 closeall = true;
 204
 205 restart:
 206         dir = opendir("/proc/self/fd");
 207         if (!dir) {
 208                 WARN("Failed to open directory: %s.", strerror(errno));
 209                 return -1;
 210         }
 211
 212         fddir = dirfd(dir);
 213
 214         while ((direntp = readdir(dir))) {
 215                 if (!direntp)
 216                         break;
 217
 218                 if (!strcmp(direntp->d_name, "."))
 219                         continue;
 220
 221                 if (!strcmp(direntp->d_name, ".."))
 222                         continue;
 223
 224                 if (lxc_safe_int(direntp->d_name, &fd) < 0) {
 225                         INFO("Could not parse file descriptor for: %s", direntp->d_name);
 226                         continue;
 227                 }
 228
 229                 for (i = 0; i < len_fds; i++)
 230                         if (fds_to_ignore[i] == fd)
 231                                 break;
 232
 233                 if (fd == fddir || fd == lxc_log_fd ||
 234                     (i < len_fds && fd == fds_to_ignore[i]))
 235                         continue;
 236
 237                 if (current_config && fd == current_config->logfd)
 238                         continue;
 239
 240                 if (match_fd(fd))
 241                         continue;
 242
 243                 if (closeall) {
 244                         close(fd);
 245                         closedir(dir);
 246                         INFO("Closed inherited fd: %d.", fd);
 247                         goto restart;
 248                 }
 249                 WARN("Inherited fd: %d.", fd);
 250         }
 251
 252         /* Only enable syslog at this point to avoid the above logging function
 253          * to open a new fd and make the check_inherited function enter an
 254          * infinite loop.
 255          */
 256         lxc_log_enable_syslog();
 257
 258         closedir(dir); /* cannot fail */
 259         return 0;
 260 }
 261
 262 static int setup_signal_fd(sigset_t *oldmask)
 263 {
 264         sigset_t mask;
 265         int fd;
 266
 267         /* Block everything except serious error signals. */
 268         if (sigfillset(&mask) ||
 269             sigdelset(&mask, SIGILL) ||
 270             sigdelset(&mask, SIGSEGV) ||
 271             sigdelset(&mask, SIGBUS) ||
 272             sigdelset(&mask, SIGWINCH) ||
 273             sigprocmask(SIG_BLOCK, &mask, oldmask)) {
 274                 SYSERROR("Failed to set signal mask.");
 275                 return -1;
 276         }
 277
 278         fd = signalfd(-1, &mask, 0);
 279         if (fd < 0) {
 280                 SYSERROR("Failed to create signal file descriptor.");
 281                 return -1;
 282         }
 283
 284         if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
 285                 SYSERROR("Failed to set FD_CLOEXEC on the signal file descriptor: %d.", fd);
 286                 close(fd);
 287                 return -1;
 288         }
 289
 290         DEBUG("Set SIGCHLD handler with file descriptor: %d.", fd);
 291
 292         return fd;
 293 }
 294
 295 static int signal_handler(int fd, uint32_t events, void *data,
 296                           struct lxc_epoll_descr *descr)
 297 {
 298         struct signalfd_siginfo siginfo;
 299         siginfo_t info;
 300         int ret;
 301         pid_t *pid = data;
 302         bool init_died = false;
 303
 304         ret = read(fd, &siginfo, sizeof(siginfo));
 305         if (ret < 0) {
 306                 ERROR("Failed to read signal info from signal file descriptor: %d.", fd);
 307                 return -1;
 308         }
 309
 310         if (ret != sizeof(siginfo)) {
 311                 ERROR("Unexpected size for siginfo struct.");
 312                 return -1;
 313         }
 314
 315         /* Check whether init is running. */
 316         info.si_pid = 0;
 317         ret = waitid(P_PID, *pid, &info, WEXITED | WNOWAIT | WNOHANG);
 318         if (ret == 0 && info.si_pid == *pid)
 319                 init_died = true;
 320
 321         if (siginfo.ssi_signo != SIGCHLD) {
 322                 kill(*pid, siginfo.ssi_signo);
 323                 INFO("Forwarded signal %d to pid %d.", siginfo.ssi_signo, *pid);
 324                 return init_died ? 1 : 0;
 325         }
 326
 327         if (siginfo.ssi_code == CLD_STOPPED) {
 328                 INFO("Container init process was stopped.");
 329                 return init_died ? 1 : 0;
 330         } else if (siginfo.ssi_code == CLD_CONTINUED) {
 331                 INFO("Container init process was continued.");
 332                 return init_died ? 1 : 0;
 333         }
 334
 335         /* More robustness, protect ourself from a SIGCHLD sent
 336          * by a process different from the container init.
 337          */
 338         if (siginfo.ssi_pid != *pid) {
 339                 NOTICE("Received SIGCHLD from pid %d instead of container init %d.", siginfo.ssi_pid, *pid);
 340                 return init_died ? 1 : 0;
 341         }
 342
 343         DEBUG("Container init process %d exited.", *pid);
 344         return 1;
 345 }
 346
 347 static int lxc_serve_state_clients(const char *name,
 348                                    struct lxc_handler *handler,
 349                                    lxc_state_t state)
 350 {
 351         ssize_t ret;
 352         struct lxc_list *cur, *next;
 353         struct state_client *client;
 354         struct lxc_msg msg = {.type = lxc_msg_state, .value = state};
 355
 356         process_lock();
 357
 358         /* Only set state under process lock held so that we don't cause
 359         *  lxc_cmd_add_state_client() to miss a state.
 360          */
 361         handler->state = state;
 362         TRACE("set container state to %s", lxc_state2str(state));
 363
 364         if (lxc_list_empty(&handler->state_clients)) {
 365                 TRACE("no state clients registered");
 366                 process_unlock();
 367                 lxc_monitor_send_state(name, state, handler->lxcpath);
 368                 return 0;
 369         }
 370
 371         strncpy(msg.name, name, sizeof(msg.name));
 372         msg.name[sizeof(msg.name) - 1] = 0;
 373
 374         lxc_list_for_each_safe(cur, &handler->state_clients, next) {
 375                 client = cur->elem;
 376
 377                 if (!client->states[state]) {
 378                         TRACE("state %s not registered for state client %d",
 379                               lxc_state2str(state), client->clientfd);
 380                         continue;
 381                 }
 382
 383                 TRACE("sending state %s to state client %d",
 384                       lxc_state2str(state), client->clientfd);
 385
 386         again:
 387                 ret = send(client->clientfd, &msg, sizeof(msg), 0);
 388                 if (ret <= 0) {
 389                         if (errno == EINTR) {
 390                                 TRACE("Caught EINTR; retrying");
 391                                 goto again;
 392                         }
 393
 394                         ERROR("failed to send message to client");
 395                 }
 396
 397                 /* kick client from list */
 398                 close(client->clientfd);
 399                 lxc_list_del(cur);
 400                 free(cur->elem);
 401                 free(cur);
 402         }
 403         process_unlock();
 404
 405         return 0;
 406 }
 407
 408 static int lxc_serve_state_socket_pair(const char *name,
 409                                        struct lxc_handler *handler,
 410                                        lxc_state_t state)
 411 {
 412         ssize_t ret;
 413
 414         if (!handler->backgrounded ||
 415             handler->state_socket_pair[1] < 0 ||
 416             state == STARTING)
 417                 return 0;
 418
 419         /* Close read end of the socket pair. */
 420         close(handler->state_socket_pair[0]);
 421         handler->state_socket_pair[0] = -1;
 422
 423 again:
 424         ret = lxc_abstract_unix_send_credential(handler->state_socket_pair[1],
 425                                                 &(int){state}, sizeof(int));
 426         if (ret != sizeof(int)) {
 427                 if (errno == EINTR)
 428                         goto again;
 429                 SYSERROR("Failed to send state to %d",
 430                          handler->state_socket_pair[1]);
 431                 return -1;
 432         }
 433
 434         TRACE("Sent container state \"%s\" to %d", lxc_state2str(state),
 435               handler->state_socket_pair[1]);
 436
 437         /* Close write end of the socket pair. */
 438         close(handler->state_socket_pair[1]);
 439         handler->state_socket_pair[1] = -1;
 440
 441         return 0;
 442 }
 443
 444 int lxc_set_state(const char *name, struct lxc_handler *handler,
 445                   lxc_state_t state)
 446 {
 447         int ret;
 448
 449         ret = lxc_serve_state_socket_pair(name, handler, state);
 450         if (ret < 0) {
 451                 ERROR("Failed to synchronize via anonymous pair of unix sockets");
 452                 return -1;
 453         }
 454
 455         ret = lxc_serve_state_clients(name, handler, state);
 456         if (ret < 0)
 457                 return -1;
 458
 459         /* This function will try to connect to the legacy lxc-monitord state
 460          * server and only exists for backwards compatibility.
 461          */
 462         lxc_monitor_send_state(name, state, handler->lxcpath);
 463
 464         return 0;
 465 }
 466
 467 int lxc_poll(const char *name, struct lxc_handler *handler)
 468 {
 469         int sigfd = handler->sigfd;
 470         int pid = handler->pid;
 471         struct lxc_epoll_descr descr;
 472
 473         if (lxc_mainloop_open(&descr)) {
 474                 ERROR("Failed to create LXC mainloop.");
 475                 goto out_sigfd;
 476         }
 477
 478         if (lxc_mainloop_add_handler(&descr, sigfd, signal_handler, &pid)) {
 479                 ERROR("Failed to add signal handler with file descriptor %d to LXC mainloop.", sigfd);
 480                 goto out_mainloop_open;
 481         }
 482
 483         if (lxc_console_mainloop_add(&descr, handler->conf)) {
 484                 ERROR("Failed to add console handler to LXC mainloop.");
 485                 goto out_mainloop_open;
 486         }
 487
 488         if (lxc_cmd_mainloop_add(name, &descr, handler)) {
 489                 ERROR("Failed to add command handler to LXC mainloop.");
 490                 goto out_mainloop_open;
 491         }
 492
 493         TRACE("lxc mainloop is ready");
 494
 495         return lxc_mainloop(&descr, -1);
 496
 497 out_mainloop_open:
 498         lxc_mainloop_close(&descr);
 499
 500 out_sigfd:
 501         close(sigfd);
 502
 503         return -1;
 504 }
 505
 506 void lxc_free_handler(struct lxc_handler *handler)
 507 {
 508         if (handler->conf && handler->conf->maincmd_fd)
 509                 close(handler->conf->maincmd_fd);
 510
 511         if (handler->state_socket_pair[0] >= 0)
 512                 close(handler->state_socket_pair[0]);
 513
 514         if (handler->state_socket_pair[1] >= 0)
 515                 close(handler->state_socket_pair[1]);
 516
 517         if (handler->name)
 518                 free(handler->name);
 519
 520         handler->conf = NULL;
 521         free(handler);
 522 }
 523
 524 struct lxc_handler *lxc_init_handler(const char *name, struct lxc_conf *conf,
 525                                      const char *lxcpath, bool daemonize)
 526 {
 527         int i, ret;
 528         struct lxc_handler *handler;
 529
 530         handler = malloc(sizeof(*handler));
 531         if (!handler) {
 532                 ERROR("failed to allocate memory");
 533                 return NULL;
 534         }
 535
 536         memset(handler, 0, sizeof(*handler));
 537
 538         /* Note that am_unpriv() checks the effective uid. We probably don't
 539          * care if we are real root only if we are running as root so this
 540          * should be fine.
 541          */
 542         handler->am_root = !am_unpriv();
 543         handler->data_sock[0] = handler->data_sock[1] = -1;
 544         handler->conf = conf;
 545         handler->lxcpath = lxcpath;
 546         handler->pinfd = -1;
 547         handler->state_socket_pair[0] = handler->state_socket_pair[1] = -1;
 548         lxc_list_init(&handler->state_clients);
 549
 550         for (i = 0; i < LXC_NS_MAX; i++)
 551                 handler->nsfd[i] = -1;
 552
 553         handler->name = strdup(name);
 554         if (!handler->name) {
 555                 ERROR("failed to allocate memory");
 556                 goto on_error;
 557         }
 558
 559         if (daemonize && !handler->conf->reboot) {
 560                 /* Create socketpair() to synchronize on daemonized startup.
 561                  * When the container reboots we don't need to synchronize again
 562                  * currently so don't open another socketpair().
 563                  */
 564                 ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
 565                                  handler->state_socket_pair);
 566                 if (ret < 0) {
 567                         ERROR("Failed to create anonymous pair of unix sockets");
 568                         goto on_error;
 569                 }
 570                 TRACE("Created anonymous pair {%d,%d} of unix sockets",
 571                       handler->state_socket_pair[0],
 572                       handler->state_socket_pair[1]);
 573         }
 574
 575         if (lxc_cmd_init(name, handler, lxcpath)) {
 576                 ERROR("failed to set up command socket");
 577                 goto on_error;
 578         }
 579
 580         TRACE("unix domain socket %d for command server is ready",
 581               handler->conf->maincmd_fd);
 582
 583         return handler;
 584
 585 on_error:
 586         lxc_free_handler(handler);
 587
 588         return NULL;
 589 }
 590
 591 int lxc_init(const char *name, struct lxc_handler *handler)
 592 {
 593         struct lxc_conf *conf = handler->conf;
 594
 595         lsm_init();
 596         TRACE("initialized LSM");
 597
 598         if (lxc_read_seccomp_config(conf) != 0) {
 599                 ERROR("Failed loading seccomp policy.");
 600                 goto out_close_maincmd_fd;
 601         }
 602         TRACE("read seccomp policy");
 603
 604         /* Begin by setting the state to STARTING. */
 605         if (lxc_set_state(name, handler, STARTING)) {
 606                 ERROR("Failed to set state for container \"%s\" to \"%s\".", name, lxc_state2str(STARTING));
 607                 goto out_close_maincmd_fd;
 608         }
 609         TRACE("set container state to \"STARTING\"");
 610
 611         /* Start of environment variable setup for hooks. */
 612         if (name && setenv("LXC_NAME", name, 1))
 613                 SYSERROR("Failed to set environment variable: LXC_NAME=%s.", name);
 614
 615         if (conf->rcfile && setenv("LXC_CONFIG_FILE", conf->rcfile, 1))
 616                 SYSERROR("Failed to set environment variable: LXC_CONFIG_FILE=%s.", conf->rcfile);
 617
 618         if (conf->rootfs.mount && setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1))
 619                 SYSERROR("Failed to set environment variable: LXC_ROOTFS_MOUNT=%s.", conf->rootfs.mount);
 620
 621         if (conf->rootfs.path && setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1))
 622                 SYSERROR("Failed to set environment variable: LXC_ROOTFS_PATH=%s.", conf->rootfs.path);
 623
 624         if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1))
 625                 SYSERROR("Failed to set environment variable: LXC_CONSOLE=%s.", conf->console.path);
 626
 627         if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1))
 628                 SYSERROR("Failed to set environment variable: LXC_CONSOLE_LOGPATH=%s.", conf->console.log_path);
 629
 630         if (setenv("LXC_CGNS_AWARE", "1", 1))
 631                 SYSERROR("Failed to set environment variable LXC_CGNS_AWARE=1.");
 632         /* End of environment variable setup for hooks. */
 633
 634         TRACE("set environment variables");
 635
 636         if (run_lxc_hooks(name, "pre-start", conf, handler->lxcpath, NULL)) {
 637                 ERROR("Failed to run lxc.hook.pre-start for container \"%s\".", name);
 638                 goto out_aborting;
 639         }
 640         TRACE("ran pre-start hooks");
 641
 642         /* The signal fd has to be created before forking otherwise if the child
 643          * process exits before we setup the signal fd, the event will be lost
 644          * and the command will be stuck.
 645          */
 646         handler->sigfd = setup_signal_fd(&handler->oldmask);
 647         if (handler->sigfd < 0) {
 648                 ERROR("Failed to setup SIGCHLD fd handler.");
 649                 goto out_delete_tty;
 650         }
 651         TRACE("set up signal fd");
 652
 653         /* Do this after setting up signals since it might unblock SIGWINCH. */
 654         if (lxc_console_create(conf)) {
 655                 ERROR("Failed to create console for container \"%s\".", name);
 656                 goto out_restore_sigmask;
 657         }
 658         TRACE("created console");
 659
 660         if (lxc_ttys_shift_ids(conf) < 0) {
 661                 ERROR("Failed to shift tty into container.");
 662                 goto out_restore_sigmask;
 663         }
 664         TRACE("shifted tty ids");
 665
 666         INFO("container \"%s\" is initialized", name);
 667         return 0;
 668
 669 out_restore_sigmask:
 670         sigprocmask(SIG_SETMASK, &handler->oldmask, NULL);
 671 out_delete_tty:
 672         lxc_delete_tty(&conf->tty_info);
 673 out_aborting:
 674         lxc_set_state(name, handler, ABORTING);
 675 out_close_maincmd_fd:
 676         close(conf->maincmd_fd);
 677         conf->maincmd_fd = -1;
 678         return -1;
 679 }
 680
 681 void lxc_fini(const char *name, struct lxc_handler *handler)
 682 {
 683         int i, rc;
 684         struct lxc_list *cur, *next;
 685         pid_t self = getpid();
 686         char *namespaces[LXC_NS_MAX + 1];
 687         size_t namespace_count = 0;
 688
 689         /* The STOPPING state is there for future cleanup code which can take
 690          * awhile.
 691          */
 692         lxc_set_state(name, handler, STOPPING);
 693
 694         for (i = 0; i < LXC_NS_MAX; i++) {
 695                 if (handler->nsfd[i] != -1) {
 696                         rc = asprintf(&namespaces[namespace_count], "%s:/proc/%d/fd/%d",
 697                                       ns_info[i].proc_name, self, handler->nsfd[i]);
 698                         if (rc == -1) {
 699                                 SYSERROR("Failed to allocate memory.");
 700                                 break;
 701                         }
 702                         ++namespace_count;
 703                 }
 704         }
 705         namespaces[namespace_count] = NULL;
 706
 707         if (handler->conf->reboot && setenv("LXC_TARGET", "reboot", 1))
 708                 SYSERROR("Failed to set environment variable: LXC_TARGET=reboot.");
 709
 710         if (!handler->conf->reboot && setenv("LXC_TARGET", "stop", 1))
 711                 SYSERROR("Failed to set environment variable: LXC_TARGET=stop.");
 712
 713         if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath, namespaces))
 714                 ERROR("Failed to run lxc.hook.stop for container \"%s\".", name);
 715
 716         while (namespace_count--)
 717                 free(namespaces[namespace_count]);
 718         for (i = 0; i < LXC_NS_MAX; i++) {
 719                 if (handler->nsfd[i] != -1) {
 720                         close(handler->nsfd[i]);
 721                         handler->nsfd[i] = -1;
 722                 }
 723         }
 724
 725         if (handler->netnsfd >= 0) {
 726                 close(handler->netnsfd);
 727                 handler->netnsfd = -1;
 728         }
 729
 730         cgroup_destroy(handler);
 731
 732         lxc_set_state(name, handler, STOPPED);
 733
 734         /* close command socket */
 735         close(handler->conf->maincmd_fd);
 736         handler->conf->maincmd_fd = -1;
 737
 738         if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL)) {
 739                 ERROR("Failed to run lxc.hook.post-stop for container \"%s\".", name);
 740                 if (handler->conf->reboot) {
 741                         WARN("Container will be stopped instead of rebooted.");
 742                         handler->conf->reboot = 0;
 743                         if (setenv("LXC_TARGET", "stop", 1))
 744                                 WARN("Failed to set environment variable: LXC_TARGET=stop.");
 745                 }
 746         }
 747
 748         /* Reset mask set by setup_signal_fd. */
 749         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
 750                 WARN("Failed to restore signal mask.");
 751
 752         lxc_console_delete(&handler->conf->console);
 753         lxc_delete_tty(&handler->conf->tty_info);
 754
 755         /* The command socket is now closed, no more state clients can register
 756          * themselves from now on. So free the list of state clients.
 757          */
 758         lxc_list_for_each_safe(cur, &handler->state_clients, next) {
 759                 struct state_client *client = cur->elem;
 760                 /* close state client socket */
 761                 close(client->clientfd);
 762                 lxc_list_del(cur);
 763                 free(cur->elem);
 764                 free(cur);
 765         }
 766
 767         if (handler->data_sock[0] != -1) {
 768                 close(handler->data_sock[0]);
 769                 close(handler->data_sock[1]);
 770         }
 771
 772         if (handler->conf->ephemeral == 1 && handler->conf->reboot != 1)
 773                 lxc_destroy_container_on_signal(handler, name);
 774
 775         free(handler->name);
 776         free(handler);
 777 }
 778
 779 void lxc_abort(const char *name, struct lxc_handler *handler)
 780 {
 781         int ret, status;
 782
 783         lxc_set_state(name, handler, ABORTING);
 784         if (handler->pid > 0)
 785                 kill(handler->pid, SIGKILL);
 786         while ((ret = waitpid(-1, &status, 0)) > 0) {
 787                 ;
 788         }
 789 }
 790
 791 static int do_start(void *data)
 792 {
 793         struct lxc_list *iterator;
 794         struct lxc_handler *handler = data;
 795         int devnull_fd = -1, ret;
 796         char path[PATH_MAX];
 797
 798         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL)) {
 799                 SYSERROR("Failed to set signal mask.");
 800                 return -1;
 801         }
 802
 803         /* This prctl must be before the synchro, so if the parent dies before
 804          * we set the parent death signal, we will detect its death with the
 805          * synchro right after, otherwise we have a window where the parent can
 806          * exit before we set the pdeath signal leading to a unsupervized
 807          * container.
 808          */
 809         if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0)) {
 810                 SYSERROR("Failed to set PR_SET_PDEATHSIG to SIGKILL.");
 811                 return -1;
 812         }
 813
 814         lxc_sync_fini_parent(handler);
 815
 816         /* Don't leak the pinfd to the container. */
 817         if (handler->pinfd >= 0) {
 818                 close(handler->pinfd);
 819         }
 820
 821         if (lxc_sync_wait_parent(handler, LXC_SYNC_STARTUP))
 822                 return -1;
 823
 824         /* Unshare CLONE_NEWNET after CLONE_NEWUSER. See
 825          * https://github.com/lxc/lxd/issues/1978.
 826          */
 827         if ((handler->clone_flags & (CLONE_NEWNET | CLONE_NEWUSER)) ==
 828             (CLONE_NEWNET | CLONE_NEWUSER)) {
 829                 ret = unshare(CLONE_NEWNET);
 830                 if (ret < 0) {
 831                         SYSERROR("Failed to unshare CLONE_NEWNET.");
 832                         goto out_warn_father;
 833                 }
 834                 INFO("Unshared CLONE_NEWNET.");
 835         }
 836
 837         /* Tell the parent task it can begin to configure the container and wait
 838          * for it to finish.
 839          */
 840         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
 841                 return -1;
 842
 843         if (lxc_network_recv_veth_names_from_parent(handler) < 0) {
 844                 ERROR("Failed to receive veth names from parent");
 845                 goto out_warn_father;
 846         }
 847
 848         /* If we are in a new user namespace, become root there to have
 849          * privilege over our namespace.
 850          */
 851         if (!lxc_list_empty(&handler->conf->id_map)) {
 852                 if (lxc_switch_uid_gid(0, 0) < 0)
 853                         goto out_warn_father;
 854
 855                 /* Drop groups only after we switched to a valid gid in the new
 856                  * user namespace.
 857                  */
 858                 if (lxc_setgroups(0, NULL) < 0)
 859                         goto out_warn_father;
 860         }
 861
 862         if (access(handler->lxcpath, X_OK)) {
 863                 print_top_failing_dir(handler->lxcpath);
 864                 goto out_warn_father;
 865         }
 866
 867         ret = snprintf(path, sizeof(path), "%s/dev/null", handler->conf->rootfs.mount);
 868         if (ret < 0 || ret >= sizeof(path))
 869                 goto out_warn_father;
 870
 871         /* In order to checkpoint restore, we need to have everything in the
 872          * same mount namespace. However, some containers may not have a
 873          * reasonable /dev (in particular, they may not have /dev/null), so we
 874          * can't set init's std fds to /dev/null by opening it from inside the
 875          * container.
 876          *
 877          * If that's the case, fall back to using the host's /dev/null. This
 878          * means that migration won't work, but at least we won't spew output
 879          * where it isn't wanted.
 880          */
 881         if (handler->backgrounded && !handler->conf->autodev && access(path, F_OK) < 0) {
 882                 devnull_fd = open_devnull();
 883
 884                 if (devnull_fd < 0)
 885                         goto out_warn_father;
 886                 WARN("Using /dev/null from the host for container init's "
 887                      "standard file descriptors. Migration will not work.");
 888         }
 889
 890         /* Ask father to setup cgroups and wait for him to finish. */
 891         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
 892                 goto out_error;
 893
 894         /* Unshare cgroup namespace after we have setup our cgroups. If we do it
 895          * earlier we end up with a wrong view of /proc/self/cgroup. For
 896          * example, assume we unshare(CLONE_NEWCGROUP) first, and then create
 897          * the cgroup for the container, say /sys/fs/cgroup/cpuset/lxc/c, then
 898          * /proc/self/cgroup would show us:
 899          *
 900          *      8:cpuset:/lxc/c
 901          *
 902          * whereas it should actually show
 903          *
 904          *      8:cpuset:/
 905          */
 906         if (cgns_supported()) {
 907                 if (unshare(CLONE_NEWCGROUP) < 0) {
 908                         INFO("Failed to unshare CLONE_NEWCGROUP.");
 909                         goto out_warn_father;
 910                 }
 911                 INFO("Unshared CLONE_NEWCGROUP.");
 912         }
 913
 914         /* Setup the container, ip, names, utsname, ... */
 915         if (lxc_setup(handler)) {
 916                 ERROR("Failed to setup container \"%s\".", handler->name);
 917                 goto out_warn_father;
 918         }
 919
 920         /* Set the label to change to when we exec(2) the container's init. */
 921         if (lsm_process_label_set(NULL, handler->conf, 1, 1) < 0)
 922                 goto out_warn_father;
 923
 924         /* Set PR_SET_NO_NEW_PRIVS after we changed the lsm label. If we do it
 925          * before we aren't allowed anymore.
 926          */
 927         if (handler->conf->no_new_privs) {
 928                 if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
 929                         SYSERROR("Could not set PR_SET_NO_NEW_PRIVS to block execve() gainable privileges.");
 930                         goto out_warn_father;
 931                 }
 932                 DEBUG("Set PR_SET_NO_NEW_PRIVS to block execve() gainable privileges.");
 933         }
 934
 935         /* Some init's such as busybox will set sane tty settings on stdin,
 936          * stdout, stderr which it thinks is the console. We already set them
 937          * the way we wanted on the real terminal, and we want init to do its
 938          * setup on its console ie. the pty allocated in lxc_console_create() so
 939          * make sure that that pty is stdin,stdout,stderr.
 940          */
 941          if (handler->conf->console.slave >= 0)
 942                  if (set_stdfds(handler->conf->console.slave) < 0) {
 943                         ERROR("Failed to redirect std{in,out,err} to pty file "
 944                               "descriptor %d",
 945                               handler->conf->console.slave);
 946                         goto out_warn_father;
 947                  }
 948
 949         /* If we mounted a temporary proc, then unmount it now. */
 950         tmp_proc_unmount(handler->conf);
 951
 952         if (lxc_seccomp_load(handler->conf) != 0)
 953                 goto out_warn_father;
 954
 955         if (run_lxc_hooks(handler->name, "start", handler->conf, handler->lxcpath, NULL)) {
 956                 ERROR("Failed to run lxc.hook.start for container \"%s\".", handler->name);
 957                 goto out_warn_father;
 958         }
 959
 960         /* The container has been setup. We can now switch to an unprivileged
 961          * uid/gid.
 962          */
 963         if (handler->conf->is_execute) {
 964                 bool have_cap_setgid;
 965                 uid_t new_uid = handler->conf->init_uid;
 966                 gid_t new_gid = handler->conf->init_gid;
 967
 968                 /* If we are in a new user namespace we already dropped all
 969                  * groups when we switched to root in the new user namespace
 970                  * further above. Only drop groups if we can, so ensure that we
 971                  * have necessary privilege.
 972                  */
 973                 #if HAVE_LIBCAP
 974                 have_cap_setgid = lxc_proc_cap_is_set(CAP_SETGID, CAP_EFFECTIVE);
 975                 #else
 976                 have_cap_setgid = false;
 977                 #endif
 978                 if (lxc_list_empty(&handler->conf->id_map) && have_cap_setgid) {
 979                         if (lxc_setgroups(0, NULL) < 0)
 980                                 goto out_warn_father;
 981                 }
 982
 983                 if (lxc_switch_uid_gid(new_uid, new_gid) < 0)
 984                         goto out_warn_father;
 985         }
 986
 987         /* The clearenv() and putenv() calls have been moved here to allow us to
 988          * use environment variables passed to the various hooks, such as the
 989          * start hook above. Not all of the variables like CONFIG_PATH or ROOTFS
 990          * are valid in this context but others are.
 991          */
 992         if (clearenv()) {
 993                 SYSERROR("Failed to clear environment.");
 994                 /* Don't error out though. */
 995         }
 996
 997         lxc_list_for_each(iterator, &handler->conf->environment) {
 998                 if (putenv((char *)iterator->elem)) {
 999                         SYSERROR("Failed to set environment variable: %s.", (char *)iterator->elem);
1000                         goto out_warn_father;
1001                 }
1002         }
1003
1004         if (putenv("container=lxc")) {
1005                 SYSERROR("Failed to set environment variable: container=lxc.");
1006                 goto out_warn_father;
1007         }
1008
1009         if (handler->conf->pty_names) {
1010                 if (putenv(handler->conf->pty_names)) {
1011                         SYSERROR("Failed to set environment variable for container ptys.");
1012                         goto out_warn_father;
1013                 }
1014         }
1015
1016         close(handler->sigfd);
1017
1018         if (devnull_fd < 0) {
1019                 devnull_fd = open_devnull();
1020
1021                 if (devnull_fd < 0)
1022                         goto out_warn_father;
1023         }
1024
1025         if (handler->conf->console.slave < 0 && handler->backgrounded)
1026                 if (set_stdfds(devnull_fd) < 0) {
1027                         ERROR("Failed to redirect std{in,out,err} to "
1028                               "\"/dev/null\"");
1029                         goto out_warn_father;
1030                 }
1031
1032         if (devnull_fd >= 0) {
1033                 close(devnull_fd);
1034                 devnull_fd = -1;
1035         }
1036
1037         setsid();
1038
1039         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP_LIMITS))
1040                 goto out_warn_father;
1041
1042         /* After this call, we are in error because this ops should not return
1043          * as it execs.
1044          */
1045         handler->ops->start(handler, handler->data);
1046
1047 out_warn_father:
1048         /* We want the parent to know something went wrong, so we return a
1049          * special error code.
1050          */
1051         lxc_sync_wake_parent(handler, LXC_SYNC_ERROR);
1052
1053 out_error:
1054         if (devnull_fd >= 0)
1055                 close(devnull_fd);
1056
1057         return -1;
1058 }
1059
1060 static int lxc_recv_ttys_from_child(struct lxc_handler *handler)
1061 {
1062         int i;
1063         struct lxc_pty_info *pty_info;
1064         int ret = -1;
1065         int sock = handler->data_sock[1];
1066         struct lxc_conf *conf = handler->conf;
1067         struct lxc_tty_info *tty_info = &conf->tty_info;
1068
1069         if (!conf->tty)
1070                 return 0;
1071
1072         tty_info->pty_info = malloc(sizeof(*tty_info->pty_info) * conf->tty);
1073         if (!tty_info->pty_info)
1074                 return -1;
1075
1076         for (i = 0; i < conf->tty; i++) {
1077                 int ttyfds[2];
1078
1079                 ret = lxc_abstract_unix_recv_fds(sock, ttyfds, 2, NULL, 0);
1080                 if (ret < 0)
1081                         break;
1082
1083                 pty_info = &tty_info->pty_info[i];
1084                 pty_info->busy = 0;
1085                 pty_info->master = ttyfds[0];
1086                 pty_info->slave = ttyfds[1];
1087                 TRACE("Received pty with master fd %d and slave fd %d from "
1088                       "parent", pty_info->master, pty_info->slave);
1089         }
1090         if (ret < 0)
1091                 ERROR("Failed to receive %d ttys from child: %s", conf->tty,
1092                       strerror(errno));
1093         else
1094                 TRACE("Received %d ttys from child", conf->tty);
1095
1096         tty_info->nbtty = conf->tty;
1097
1098         return ret;
1099 }
1100
1101 void resolve_clone_flags(struct lxc_handler *handler)
1102 {
1103         handler->clone_flags = CLONE_NEWPID | CLONE_NEWNS;
1104
1105         if (!lxc_list_empty(&handler->conf->id_map))
1106                 handler->clone_flags |= CLONE_NEWUSER;
1107
1108         if (handler->conf->inherit_ns_fd[LXC_NS_NET] == -1) {
1109                 if (!lxc_requests_empty_network(handler))
1110                         handler->clone_flags |= CLONE_NEWNET;
1111         } else {
1112                 INFO("Inheriting a NET namespace.");
1113         }
1114
1115         if (handler->conf->inherit_ns_fd[LXC_NS_IPC] == -1)
1116                 handler->clone_flags |= CLONE_NEWIPC;
1117         else
1118                 INFO("Inheriting an IPC namespace.");
1119
1120         if (handler->conf->inherit_ns_fd[LXC_NS_UTS] == -1)
1121                 handler->clone_flags |= CLONE_NEWUTS;
1122         else
1123                 INFO("Inheriting a UTS namespace.");
1124 }
1125
1126 /* lxc_spawn() performs crucial setup tasks and clone()s the new process which
1127  * exec()s the requested container binary.
1128  * Note that lxc_spawn() runs in the parent namespaces. Any operations performed
1129  * right here should be double checked if they'd pose a security risk. (For
1130  * example, any {u}mount() operations performed here will be reflected on the
1131  * host!)
1132  */
1133 static int lxc_spawn(struct lxc_handler *handler)
1134 {
1135         int i, flags, ret;
1136         const char *name = handler->name;
1137         bool wants_to_map_ids;
1138         int saved_ns_fd[LXC_NS_MAX];
1139         struct lxc_list *id_map;
1140         int failed_before_rename = 0, preserve_mask = 0;
1141         bool cgroups_connected = false;
1142
1143         id_map = &handler->conf->id_map;
1144         wants_to_map_ids = !lxc_list_empty(id_map);
1145
1146         for (i = 0; i < LXC_NS_MAX; i++)
1147                 if (handler->conf->inherit_ns_fd[i] != -1)
1148                         preserve_mask |= ns_info[i].clone_flag;
1149
1150         if (lxc_sync_init(handler))
1151                 return -1;
1152
1153         ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
1154                          handler->data_sock);
1155         if (ret < 0) {
1156                 lxc_sync_fini(handler);
1157                 return -1;
1158         }
1159
1160         resolve_clone_flags(handler);
1161
1162         if (handler->clone_flags & CLONE_NEWNET) {
1163                 if (!lxc_list_empty(&handler->conf->network)) {
1164
1165                         /* Find gateway addresses from the link device, which is
1166                          * no longer accessible inside the container. Do this
1167                          * before creating network interfaces, since goto
1168                          * out_delete_net does not work before lxc_clone.
1169                          */
1170                         if (lxc_find_gateway_addresses(handler)) {
1171                                 ERROR("Failed to find gateway addresses.");
1172                                 lxc_sync_fini(handler);
1173                                 return -1;
1174                         }
1175
1176                         /* That should be done before the clone because we will
1177                          * fill the netdev index and use them in the child.
1178                          */
1179                         if (lxc_create_network_priv(handler)) {
1180                                 ERROR("Failed to create the network.");
1181                                 lxc_sync_fini(handler);
1182                                 return -1;
1183                         }
1184                 }
1185         }
1186
1187         if (!cgroup_init(handler)) {
1188                 ERROR("Failed initializing cgroup support.");
1189                 goto out_delete_net;
1190         }
1191
1192         cgroups_connected = true;
1193
1194         if (!cgroup_create(handler)) {
1195                 ERROR("Failed creating cgroups.");
1196                 goto out_delete_net;
1197         }
1198
1199         /* If the rootfs is not a blockdev, prevent the container from marking
1200          * it readonly.
1201          * If the container is unprivileged then skip rootfs pinning.
1202          */
1203         if (!wants_to_map_ids) {
1204                 handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
1205                 if (handler->pinfd == -1)
1206                         INFO("Failed to pin the rootfs for container \"%s\".", handler->name);
1207         }
1208
1209         if (!preserve_ns(saved_ns_fd, preserve_mask, getpid()))
1210                 goto out_delete_net;
1211
1212         if (attach_ns(handler->conf->inherit_ns_fd) < 0)
1213                 goto out_delete_net;
1214
1215         /* Create a process in a new set of namespaces. */
1216         flags = handler->clone_flags;
1217         if (handler->clone_flags & CLONE_NEWUSER) {
1218                 /* If CLONE_NEWUSER and CLONE_NEWNET was requested, we need to
1219                  * clone a new user namespace first and only later unshare our
1220                  * network namespace to ensure that network devices ownership is
1221                  * set up correctly.
1222                  */
1223                 flags &= ~CLONE_NEWNET;
1224         }
1225         handler->pid = lxc_clone(do_start, handler, flags);
1226         if (handler->pid < 0) {
1227                 SYSERROR("Failed to clone a new set of namespaces.");
1228                 goto out_delete_net;
1229         }
1230
1231         for (i = 0; i < LXC_NS_MAX; i++)
1232                 if (flags & ns_info[i].clone_flag)
1233                         INFO("Cloned %s.", ns_info[i].flag_name);
1234
1235         if (!preserve_ns(handler->nsfd, handler->clone_flags | preserve_mask, handler->pid))
1236                 INFO("Failed to preserve namespace for lxc.hook.stop.");
1237
1238         if (attach_ns(saved_ns_fd))
1239                 WARN("Failed to restore saved namespaces.");
1240
1241         lxc_sync_fini_child(handler);
1242
1243         /* Map the container uids. The container became an invalid userid the
1244          * moment it was cloned with CLONE_NEWUSER. This call doesn't change
1245          * anything immediately, but allows the container to setuid(0) (0 being
1246          * mapped to something else on the host.) later to become a valid uid
1247          * again.
1248          */
1249         if (wants_to_map_ids && lxc_map_ids(id_map, handler->pid)) {
1250                 ERROR("Failed to set up id mapping.");
1251                 goto out_delete_net;
1252         }
1253
1254         if (lxc_sync_wake_child(handler, LXC_SYNC_STARTUP)) {
1255                 failed_before_rename = 1;
1256                 goto out_delete_net;
1257         }
1258
1259         if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE)) {
1260                 failed_before_rename = 1;
1261                 goto out_delete_net;
1262         }
1263
1264         if (!cgroup_create_legacy(handler)) {
1265                 ERROR("Failed to setup legacy cgroups for container \"%s\".", name);
1266                 goto out_delete_net;
1267         }
1268         if (!cgroup_setup_limits(handler, false)) {
1269                 ERROR("Failed to setup cgroup limits for container \"%s\".", name);
1270                 goto out_delete_net;
1271         }
1272
1273         if (!cgroup_enter(handler))
1274                 goto out_delete_net;
1275
1276         if (!cgroup_chown(handler))
1277                 goto out_delete_net;
1278
1279         if (failed_before_rename)
1280                 goto out_delete_net;
1281
1282         handler->netnsfd = lxc_preserve_ns(handler->pid, "net");
1283         if (handler->netnsfd < 0) {
1284                 ERROR("Failed to preserve network namespace");
1285                 goto out_delete_net;
1286         }
1287
1288         /* Create the network configuration. */
1289         if (handler->clone_flags & CLONE_NEWNET) {
1290                 if (lxc_network_move_created_netdev_priv(handler->lxcpath,
1291                                                          handler->name,
1292                                                          &handler->conf->network,
1293                                                          handler->pid)) {
1294                         ERROR("Failed to create the configured network.");
1295                         goto out_delete_net;
1296                 }
1297
1298                 if (lxc_create_network_unpriv(handler->lxcpath, handler->name,
1299                                               &handler->conf->network,
1300                                               handler->pid)) {
1301                         ERROR("Failed to create the configured network.");
1302                         goto out_delete_net;
1303                 }
1304         }
1305
1306         if (lxc_network_send_veth_names_to_child(handler) < 0) {
1307                 ERROR("Failed to send veth names to child");
1308                 goto out_delete_net;
1309         }
1310
1311         /* Tell the child to continue its initialization. We'll get
1312          * LXC_SYNC_CGROUP when it is ready for us to setup cgroups.
1313          */
1314         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
1315                 goto out_delete_net;
1316
1317         if (!lxc_list_empty(&handler->conf->limits) && setup_resource_limits(&handler->conf->limits, handler->pid)) {
1318                 ERROR("failed to setup resource limits for '%s'", name);
1319                 goto out_delete_net;
1320         }
1321
1322         if (lxc_sync_barrier_child(handler, LXC_SYNC_CGROUP_UNSHARE))
1323                 goto out_delete_net;
1324
1325         if (!cgroup_setup_limits(handler, true)) {
1326                 ERROR("Failed to setup the devices cgroup for container \"%s\".", name);
1327                 goto out_delete_net;
1328         }
1329         TRACE("Set up cgroup device limits");
1330
1331         cgroup_disconnect();
1332         cgroups_connected = false;
1333
1334         /* Tell the child to complete its initialization and wait for it to exec
1335          * or return an error. (The child will never return
1336          * LXC_SYNC_POST_CGROUP+1. It will either close the sync pipe, causing
1337          * lxc_sync_barrier_child to return success, or return a different
1338          * value, causing us to error out).
1339          */
1340         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
1341                 return -1;
1342
1343         if (lxc_network_recv_name_and_ifindex_from_child(handler) < 0) {
1344                 ERROR("Failed to receive names and ifindices for network "
1345                       "devices from child");
1346                 goto out_delete_net;
1347         }
1348
1349         /* Now all networks are created, network devices are moved into place,
1350          * and the correct names and ifindeces in the respective namespaces have
1351          * been recorded. The corresponding structs have now all been filled. So
1352          * log them for debugging purposes.
1353          */
1354         lxc_log_configured_netdevs(handler->conf);
1355
1356         /* Read tty fds allocated by child. */
1357         if (lxc_recv_ttys_from_child(handler) < 0) {
1358                 ERROR("Failed to receive tty info from child process.");
1359                 goto out_delete_net;
1360         }
1361
1362         if (handler->ops->post_start(handler, handler->data))
1363                 goto out_abort;
1364
1365         if (lxc_set_state(name, handler, RUNNING)) {
1366                 ERROR("Failed to set state for container \"%s\" to \"%s\".", name,
1367                       lxc_state2str(RUNNING));
1368                 goto out_abort;
1369         }
1370
1371         lxc_sync_fini(handler);
1372
1373         return 0;
1374
1375 out_delete_net:
1376         if (cgroups_connected)
1377                 cgroup_disconnect();
1378
1379         if (handler->clone_flags & CLONE_NEWNET) {
1380                 DEBUG("Tearing down network devices");
1381                 if (!lxc_delete_network_priv(handler))
1382                         DEBUG("Failed tearing down network devices");
1383
1384                 if (!lxc_delete_network_unpriv(handler))
1385                         DEBUG("Failed tearing down network devices");
1386         }
1387
1388 out_abort:
1389         lxc_abort(name, handler);
1390         lxc_sync_fini(handler);
1391         if (handler->pinfd >= 0) {
1392                 close(handler->pinfd);
1393                 handler->pinfd = -1;
1394         }
1395
1396         if (handler->netnsfd >= 0) {
1397                 close(handler->netnsfd);
1398                 handler->netnsfd = -1;
1399         }
1400
1401         return -1;
1402 }
1403
1404 int __lxc_start(const char *name, struct lxc_handler *handler,
1405                 struct lxc_operations* ops, void *data, const char *lxcpath,
1406                 bool backgrounded)
1407 {
1408         int status;
1409         int err = -1;
1410         struct lxc_conf *conf = handler->conf;
1411
1412         if (lxc_init(name, handler) < 0) {
1413                 ERROR("Failed to initialize container \"%s\".", name);
1414                 return -1;
1415         }
1416         handler->ops = ops;
1417         handler->data = data;
1418         handler->backgrounded = backgrounded;
1419         handler->netnsfd = -1;
1420
1421         if (!attach_block_device(handler->conf)) {
1422                 ERROR("Failed to attach block device.");
1423                 goto out_fini_nonet;
1424         }
1425
1426         if (geteuid() == 0 && !lxc_list_empty(&conf->id_map)) {
1427                 /* If the backing store is a device, mount it here and now. */
1428                 if (rootfs_is_blockdev(conf)) {
1429                         if (unshare(CLONE_NEWNS) < 0) {
1430                                 ERROR("Failed to unshare CLONE_NEWNS.");
1431                                 goto out_fini_nonet;
1432                         }
1433                         INFO("Unshared CLONE_NEWNS.");
1434
1435                         remount_all_slave();
1436                         if (do_rootfs_setup(conf, name, lxcpath) < 0) {
1437                                 ERROR("Error setting up rootfs mount as root before spawn.");
1438                                 goto out_fini_nonet;
1439                         }
1440                         INFO("Set up container rootfs as host root.");
1441                 }
1442         }
1443
1444         err = lxc_spawn(handler);
1445         if (err) {
1446                 ERROR("Failed to spawn container \"%s\".", name);
1447                 goto out_detach_blockdev;
1448         }
1449
1450         handler->conf->reboot = 0;
1451
1452         err = lxc_poll(name, handler);
1453         if (err) {
1454                 ERROR("LXC mainloop exited with error: %d.", err);
1455                 goto out_abort;
1456         }
1457
1458         while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
1459                 continue;
1460
1461         /* If the child process exited but was not signaled, it didn't call
1462          * reboot. This should mean it was an lxc-execute which simply exited.
1463          * In any case, treat it as a 'halt'.
1464          */
1465         if (WIFSIGNALED(status)) {
1466                 switch(WTERMSIG(status)) {
1467                 case SIGINT: /* halt */
1468                         DEBUG("Container \"%s\" is halting.", name);
1469                         break;
1470                 case SIGHUP: /* reboot */
1471                         DEBUG("Container \"%s\" is rebooting.", name);
1472                         handler->conf->reboot = 1;
1473                         break;
1474                 case SIGSYS: /* seccomp */
1475                         DEBUG("Container \"%s\" violated its seccomp policy.", name);
1476                         break;
1477                 default:
1478                         DEBUG("Unknown exit status for container \"%s\" init %d.", name, WTERMSIG(status));
1479                         break;
1480                 }
1481         }
1482
1483         err = lxc_restore_phys_nics_to_netns(handler);
1484         if (err < 0)
1485                 ERROR("Failed to move physical network devices back to parent "
1486                       "network namespace");
1487
1488         if (handler->pinfd >= 0) {
1489                 close(handler->pinfd);
1490                 handler->pinfd = -1;
1491         }
1492
1493         lxc_monitor_send_exit_code(name, status, handler->lxcpath);
1494         err =  lxc_error_set_and_log(handler->pid, status);
1495
1496 out_fini:
1497         DEBUG("Tearing down network devices");
1498         if (!lxc_delete_network_priv(handler))
1499                 DEBUG("Failed tearing down network devices");
1500
1501         if (!lxc_delete_network_unpriv(handler))
1502                 DEBUG("Failed tearing down network devices");
1503
1504         if (handler->netnsfd >= 0) {
1505                 close(handler->netnsfd);
1506                 handler->netnsfd = -1;
1507         }
1508
1509 out_detach_blockdev:
1510         detach_block_device(handler->conf);
1511
1512 out_fini_nonet:
1513         lxc_fini(name, handler);
1514         return err;
1515
1516 out_abort:
1517         lxc_abort(name, handler);
1518         goto out_fini;
1519 }
1520
1521 struct start_args {
1522         char *const *argv;
1523 };
1524
1525 static int start(struct lxc_handler *handler, void* data)
1526 {
1527         struct start_args *arg = data;
1528
1529         NOTICE("Exec'ing \"%s\".", arg->argv[0]);
1530
1531         execvp(arg->argv[0], arg->argv);
1532         SYSERROR("Failed to exec \"%s\".", arg->argv[0]);
1533         return 0;
1534 }
1535
1536 static int post_start(struct lxc_handler *handler, void* data)
1537 {
1538         struct start_args *arg = data;
1539
1540         NOTICE("Started \"%s\" with pid \"%d\".", arg->argv[0], handler->pid);
1541         return 0;
1542 }
1543
1544 static struct lxc_operations start_ops = {
1545         .start = start,
1546         .post_start = post_start
1547 };
1548
1549 int lxc_start(const char *name, char *const argv[], struct lxc_handler *handler,
1550               const char *lxcpath, bool backgrounded)
1551 {
1552         struct start_args start_arg = {
1553                 .argv = argv,
1554         };
1555
1556         return __lxc_start(name, handler, &start_ops, &start_arg, lxcpath, backgrounded);
1557 }
1558
1559 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
1560                                             const char *name)
1561 {
1562         char destroy[MAXPATHLEN];
1563         bool bret = true;
1564         int ret = 0;
1565         struct lxc_container *c;
1566         if (handler->conf->rootfs.path && handler->conf->rootfs.mount) {
1567                 bret = do_destroy_container(handler);
1568                 if (!bret) {
1569                         ERROR("Error destroying rootfs for container \"%s\".", name);
1570                         return;
1571                 }
1572         }
1573         INFO("Destroyed rootfs for container \"%s\".", name);
1574
1575         ret = snprintf(destroy, MAXPATHLEN, "%s/%s", handler->lxcpath, name);
1576         if (ret < 0 || ret >= MAXPATHLEN) {
1577                 ERROR("Error destroying directory for container \"%s\".", name);
1578                 return;
1579         }
1580
1581         c = lxc_container_new(name, handler->lxcpath);
1582         if (c) {
1583                 if (container_disk_lock(c)) {
1584                         INFO("Could not update lxc_snapshots file.");
1585                         lxc_container_put(c);
1586                 } else {
1587                         mod_all_rdeps(c, false);
1588                         container_disk_unlock(c);
1589                         lxc_container_put(c);
1590                 }
1591         }
1592
1593         if (!handler->am_root)
1594                 ret = userns_exec_1(handler->conf, lxc_rmdir_onedev_wrapper,
1595                                     destroy, "lxc_rmdir_onedev_wrapper");
1596         else
1597                 ret = lxc_rmdir_onedev(destroy, NULL);
1598
1599         if (ret < 0) {
1600                 ERROR("Error destroying directory for container \"%s\".", name);
1601                 return;
1602         }
1603         INFO("Destroyed directory for container \"%s\".", name);
1604 }
1605
1606 static int lxc_rmdir_onedev_wrapper(void *data)
1607 {
1608         char *arg = (char *) data;
1609         return lxc_rmdir_onedev(arg, NULL);
1610 }
1611
1612 static bool do_destroy_container(struct lxc_handler *handler) {
1613         if (!handler->am_root) {
1614                 if (userns_exec_1(handler->conf, storage_destroy_wrapper,
1615                                   handler->conf, "storage_destroy_wrapper") < 0)
1616                         return false;
1617
1618                 return true;
1619         }
1620
1621         return storage_destroy(handler->conf);
1622 }