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