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 #include "config.h"
  25
  26 #include <stdio.h>
  27 #undef _GNU_SOURCE
  28 #include <string.h>
  29 #include <stdlib.h>
  30 #include <dirent.h>
  31 #include <errno.h>
  32 #include <unistd.h>
  33 #include <signal.h>
  34 #include <fcntl.h>
  35 #include <termios.h>
  36 #include <sys/param.h>
  37 #include <sys/file.h>
  38 #include <sys/mount.h>
  39 #include <sys/stat.h>
  40 #include <sys/types.h>
  41 #include <sys/socket.h>
  42 #include <sys/prctl.h>
  43 #include <sys/types.h>
  44 #include <sys/wait.h>
  45 #include <sys/un.h>
  46 #include <sys/poll.h>
  47 #include <sys/syscall.h>
  48
  49 #if HAVE_SYS_CAPABILITY_H
  50 #include <sys/capability.h>
  51 #endif
  52
  53 #if !HAVE_DECL_PR_CAPBSET_DROP
  54 #define PR_CAPBSET_DROP 24
  55 #endif
  56
  57 #include "start.h"
  58 #include "conf.h"
  59 #include "log.h"
  60 #include "cgroup.h"
  61 #include "error.h"
  62 #include "af_unix.h"
  63 #include "mainloop.h"
  64 #include "utils.h"
  65 #include "lxcutmp.h"
  66 #include "monitor.h"
  67 #include "commands.h"
  68 #include "console.h"
  69 #include "sync.h"
  70 #include "namespace.h"
  71 #include "apparmor.h"
  72 #include "lxcseccomp.h"
  73 #include "caps.h"
  74
  75 lxc_log_define(lxc_start, lxc);
  76
  77 static int match_fd(int fd)
  78 {
  79         return (fd == 0 || fd == 1 || fd == 2);
  80 }
  81
  82 int lxc_check_inherited(struct lxc_conf *conf, int fd_to_ignore)
  83 {
  84         struct dirent dirent, *direntp;
  85         int fd, fddir;
  86         DIR *dir;
  87
  88 restart:
  89         dir = opendir("/proc/self/fd");
  90         if (!dir) {
  91                 WARN("failed to open directory: %m");
  92                 return -1;
  93         }
  94
  95         fddir = dirfd(dir);
  96
  97         while (!readdir_r(dir, &dirent, &direntp)) {
  98                 if (!direntp)
  99                         break;
 100
 101                 if (!strcmp(direntp->d_name, "."))
 102                         continue;
 103
 104                 if (!strcmp(direntp->d_name, ".."))
 105                         continue;
 106
 107                 fd = atoi(direntp->d_name);
 108
 109                 if (fd == fddir || fd == lxc_log_fd || fd == fd_to_ignore)
 110                         continue;
 111
 112                 if (match_fd(fd))
 113                         continue;
 114
 115                 if (conf->close_all_fds) {
 116                         close(fd);
 117                         closedir(dir);
 118                         INFO("closed inherited fd %d", fd);
 119                         goto restart;
 120                 }
 121                 WARN("inherited fd %d", fd);
 122         }
 123
 124         closedir(dir); /* cannot fail */
 125         return 0;
 126 }
 127
 128 static int setup_signal_fd(sigset_t *oldmask)
 129 {
 130         sigset_t mask;
 131         int fd;
 132
 133         /* Block everything except serious error signals */
 134         if (sigfillset(&mask) ||
 135             sigdelset(&mask, SIGILL) ||
 136             sigdelset(&mask, SIGSEGV) ||
 137             sigdelset(&mask, SIGBUS) ||
 138             sigdelset(&mask, SIGWINCH) ||
 139             sigprocmask(SIG_BLOCK, &mask, oldmask)) {
 140                 SYSERROR("failed to set signal mask");
 141                 return -1;
 142         }
 143
 144         fd = signalfd(-1, &mask, 0);
 145         if (fd < 0) {
 146                 SYSERROR("failed to create the signal fd");
 147                 return -1;
 148         }
 149
 150         if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
 151                 SYSERROR("failed to set sigfd to close-on-exec");
 152                 close(fd);
 153                 return -1;
 154         }
 155
 156         DEBUG("sigchild handler set");
 157
 158         return fd;
 159 }
 160
 161 static int signal_handler(int fd, void *data,
 162                            struct lxc_epoll_descr *descr)
 163 {
 164         struct signalfd_siginfo siginfo;
 165         siginfo_t info;
 166         int ret;
 167         pid_t *pid = data;
 168         bool init_died = false;
 169
 170         ret = read(fd, &siginfo, sizeof(siginfo));
 171         if (ret < 0) {
 172                 ERROR("failed to read signal info");
 173                 return -1;
 174         }
 175
 176         if (ret != sizeof(siginfo)) {
 177                 ERROR("unexpected siginfo size");
 178                 return -1;
 179         }
 180
 181         // check whether init is running
 182         info.si_pid = 0;
 183         ret = waitid(P_PID, *pid, &info, WEXITED | WNOWAIT | WNOHANG);
 184         if (ret == 0 && info.si_pid == *pid) {
 185                 init_died = true;
 186         }
 187
 188         if (siginfo.ssi_signo != SIGCHLD) {
 189                 kill(*pid, siginfo.ssi_signo);
 190                 INFO("forwarded signal %d to pid %d", siginfo.ssi_signo, *pid);
 191                 return init_died ? 1 : 0;
 192         }
 193
 194         if (siginfo.ssi_code == CLD_STOPPED ||
 195             siginfo.ssi_code == CLD_CONTINUED) {
 196                 INFO("container init process was stopped/continued");
 197                 return init_died ? 1 : 0;
 198         }
 199
 200         /* more robustness, protect ourself from a SIGCHLD sent
 201          * by a process different from the container init
 202          */
 203         if (siginfo.ssi_pid != *pid) {
 204                 WARN("invalid pid for SIGCHLD");
 205                 return init_died ? 1 : 0;
 206         }
 207
 208         DEBUG("container init process exited");
 209         return 1;
 210 }
 211
 212 int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
 213 {
 214         handler->state = state;
 215         lxc_monitor_send_state(name, state, handler->lxcpath);
 216         return 0;
 217 }
 218
 219 int lxc_poll(const char *name, struct lxc_handler *handler)
 220 {
 221         int sigfd = handler->sigfd;
 222         int pid = handler->pid;
 223         struct lxc_epoll_descr descr;
 224
 225         if (lxc_mainloop_open(&descr)) {
 226                 ERROR("failed to create mainloop");
 227                 goto out_sigfd;
 228         }
 229
 230         if (lxc_mainloop_add_handler(&descr, sigfd, signal_handler, &pid)) {
 231                 ERROR("failed to add handler for the signal");
 232                 goto out_mainloop_open;
 233         }
 234
 235         if (lxc_console_mainloop_add(&descr, handler)) {
 236                 ERROR("failed to add console handler to mainloop");
 237                 goto out_mainloop_open;
 238         }
 239
 240         if (lxc_cmd_mainloop_add(name, &descr, handler)) {
 241                 ERROR("failed to add command handler to mainloop");
 242                 goto out_mainloop_open;
 243         }
 244
 245         if (handler->conf->need_utmp_watch) {
 246                 #if HAVE_SYS_CAPABILITY_H
 247                 if (lxc_utmp_mainloop_add(&descr, handler)) {
 248                         ERROR("failed to add utmp handler to mainloop");
 249                         goto out_mainloop_open;
 250                 }
 251                 #else
 252                         DEBUG("not starting utmp handler as cap_sys_boot cannot be dropped without capabilities support\n");
 253                 #endif
 254         }
 255
 256         return lxc_mainloop(&descr, -1);
 257
 258 out_mainloop_open:
 259         lxc_mainloop_close(&descr);
 260 out_sigfd:
 261         close(sigfd);
 262         return -1;
 263 }
 264
 265 struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char *lxcpath)
 266 {
 267         struct lxc_handler *handler;
 268
 269         handler = malloc(sizeof(*handler));
 270         if (!handler)
 271                 return NULL;
 272
 273         memset(handler, 0, sizeof(*handler));
 274
 275         handler->conf = conf;
 276         handler->lxcpath = lxcpath;
 277         handler->pinfd = -1;
 278
 279         apparmor_handler_init(handler);
 280         handler->name = strdup(name);
 281         if (!handler->name) {
 282                 ERROR("failed to allocate memory");
 283                 goto out_free;
 284         }
 285
 286         if (lxc_cmd_init(name, handler, lxcpath))
 287                 goto out_free_name;
 288
 289         if (lxc_read_seccomp_config(conf) != 0) {
 290                 ERROR("failed loading seccomp policy");
 291                 goto out_close_maincmd_fd;
 292         }
 293
 294         /* Begin by setting the state to STARTING */
 295         if (lxc_set_state(name, handler, STARTING)) {
 296                 ERROR("failed to set state '%s'", lxc_state2str(STARTING));
 297                 goto out_close_maincmd_fd;
 298         }
 299
 300         /* Start of environment variable setup for hooks */
 301         if (setenv("LXC_NAME", name, 1)) {
 302                 SYSERROR("failed to set environment variable for container name");
 303         }
 304         if (setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
 305                 SYSERROR("failed to set environment variable for config path");
 306         }
 307         if (setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
 308                 SYSERROR("failed to set environment variable for rootfs mount");
 309         }
 310         if (setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
 311                 SYSERROR("failed to set environment variable for rootfs mount");
 312         }
 313         if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
 314                 SYSERROR("failed to set environment variable for console path");
 315         }
 316         if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
 317                 SYSERROR("failed to set environment variable for console log");
 318         }
 319         /* End of environment variable setup for hooks */
 320
 321         if (run_lxc_hooks(name, "pre-start", conf, handler->lxcpath, NULL)) {
 322                 ERROR("failed to run pre-start hooks for container '%s'.", name);
 323                 goto out_aborting;
 324         }
 325
 326         if (lxc_create_tty(name, conf)) {
 327                 ERROR("failed to create the ttys");
 328                 goto out_aborting;
 329         }
 330
 331         /* the signal fd has to be created before forking otherwise
 332          * if the child process exits before we setup the signal fd,
 333          * the event will be lost and the command will be stuck */
 334         handler->sigfd = setup_signal_fd(&handler->oldmask);
 335         if (handler->sigfd < 0) {
 336                 ERROR("failed to set sigchild fd handler");
 337                 goto out_delete_tty;
 338         }
 339
 340         /* do this after setting up signals since it might unblock SIGWINCH */
 341         if (lxc_console_create(conf)) {
 342                 ERROR("failed to create console");
 343                 goto out_restore_sigmask;
 344         }
 345
 346         INFO("'%s' is initialized", name);
 347         return handler;
 348
 349 out_restore_sigmask:
 350         sigprocmask(SIG_SETMASK, &handler->oldmask, NULL);
 351 out_delete_tty:
 352         lxc_delete_tty(&conf->tty_info);
 353 out_aborting:
 354         lxc_set_state(name, handler, ABORTING);
 355 out_close_maincmd_fd:
 356         close(conf->maincmd_fd);
 357         conf->maincmd_fd = -1;
 358 out_free_name:
 359         free(handler->name);
 360         handler->name = NULL;
 361 out_free:
 362         free(handler);
 363         return NULL;
 364 }
 365
 366 static void lxc_fini(const char *name, struct lxc_handler *handler)
 367 {
 368         /* The STOPPING state is there for future cleanup code
 369          * which can take awhile
 370          */
 371         lxc_set_state(name, handler, STOPPING);
 372         lxc_set_state(name, handler, STOPPED);
 373
 374         if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL))
 375                 ERROR("failed to run post-stop hooks for container '%s'.", name);
 376
 377         /* reset mask set by setup_signal_fd */
 378         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
 379                 WARN("failed to restore sigprocmask");
 380
 381         lxc_console_delete(&handler->conf->console);
 382         lxc_delete_tty(&handler->conf->tty_info);
 383         close(handler->conf->maincmd_fd);
 384         handler->conf->maincmd_fd = -1;
 385         free(handler->name);
 386         if (handler->cgroup) {
 387                 lxc_cgroup_destroy_desc(handler->cgroup);
 388                 handler->cgroup = NULL;
 389         }
 390         free(handler);
 391 }
 392
 393 void lxc_abort(const char *name, struct lxc_handler *handler)
 394 {
 395         int ret, status;
 396
 397         lxc_set_state(name, handler, ABORTING);
 398         if (handler->pid > 0)
 399                 kill(handler->pid, SIGKILL);
 400         while ((ret = waitpid(-1, &status, 0)) > 0) ;
 401 }
 402
 403 #include <sys/reboot.h>
 404 #include <linux/reboot.h>
 405
 406 /*
 407  * reboot(LINUX_REBOOT_CMD_CAD_ON) will return -EINVAL
 408  * in a child pid namespace if container reboot support exists.
 409  * Otherwise, it will either succeed or return -EPERM.
 410  */
 411 static int container_reboot_supported(void *arg)
 412 {
 413         int *cmd = arg;
 414         int ret;
 415
 416         ret = reboot(*cmd);
 417         if (ret == -1 && errno == EINVAL)
 418                 return 1;
 419         return 0;
 420 }
 421
 422 static int must_drop_cap_sys_boot(struct lxc_conf *conf)
 423 {
 424         FILE *f = fopen("/proc/sys/kernel/ctrl-alt-del", "r");
 425         int ret, cmd, v, flags;
 426         long stack_size = 4096;
 427         void *stack = alloca(stack_size);
 428         int status;
 429         pid_t pid;
 430
 431         if (!f) {
 432                 DEBUG("failed to open /proc/sys/kernel/ctrl-alt-del");
 433                 return 1;
 434         }
 435
 436         ret = fscanf(f, "%d", &v);
 437         fclose(f);
 438         if (ret != 1) {
 439                 DEBUG("Failed to read /proc/sys/kernel/ctrl-alt-del");
 440                 return 1;
 441         }
 442         cmd = v ? LINUX_REBOOT_CMD_CAD_ON : LINUX_REBOOT_CMD_CAD_OFF;
 443
 444         flags = CLONE_NEWPID | SIGCHLD;
 445         if (!lxc_list_empty(&conf->id_map))
 446                 flags |= CLONE_NEWUSER;
 447
 448 #ifdef __ia64__
 449         pid = __clone2(container_reboot_supported, stack, stack_size, flags,  &cmd);
 450 #else
 451         stack += stack_size;
 452         pid = clone(container_reboot_supported, stack, flags, &cmd);
 453 #endif
 454         if (pid < 0) {
 455                 SYSERROR("failed to clone\n");
 456                 return -1;
 457         }
 458         if (wait(&status) < 0) {
 459                 SYSERROR("unexpected wait error: %m\n");
 460                 return -1;
 461         }
 462
 463         if (WEXITSTATUS(status) != 1)
 464                 return 1;
 465
 466         return 0;
 467 }
 468
 469 static int do_start(void *data)
 470 {
 471         struct lxc_handler *handler = data;
 472
 473         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL)) {
 474                 SYSERROR("failed to set sigprocmask");
 475                 return -1;
 476         }
 477
 478         /* This prctl must be before the synchro, so if the parent
 479          * dies before we set the parent death signal, we will detect
 480          * its death with the synchro right after, otherwise we have
 481          * a window where the parent can exit before we set the pdeath
 482          * signal leading to a unsupervized container.
 483          */
 484         if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0)) {
 485                 SYSERROR("failed to set pdeath signal");
 486                 return -1;
 487         }
 488
 489         lxc_sync_fini_parent(handler);
 490
 491         /* don't leak the pinfd to the container */
 492         if (handler->pinfd >= 0)
 493                 close(handler->pinfd);
 494
 495         /* Tell the parent task it can begin to configure the
 496          * container and wait for it to finish
 497          */
 498         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
 499                 return -1;
 500
 501         /*
 502          * if we are in a new user namespace, become root there to have
 503          * privilege over our namespace
 504          */
 505         if (!lxc_list_empty(&handler->conf->id_map)) {
 506                 NOTICE("switching to gid/uid 0 in new user namespace");
 507                 if (setgid(0)) {
 508                         SYSERROR("setgid");
 509                         goto out_warn_father;
 510                 }
 511                 if (setuid(0)) {
 512                         SYSERROR("setuid");
 513                         goto out_warn_father;
 514                 }
 515         }
 516
 517         #if HAVE_SYS_CAPABILITY_H
 518         if (handler->conf->need_utmp_watch) {
 519                 if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
 520                         SYSERROR("failed to remove CAP_SYS_BOOT capability");
 521                         goto out_warn_father;
 522                 }
 523                 DEBUG("Dropped cap_sys_boot\n");
 524         }
 525         #endif
 526
 527         /* Setup the container, ip, names, utsname, ... */
 528         if (lxc_setup(handler->name, handler->conf, handler->lxcpath)) {
 529                 ERROR("failed to setup the container");
 530                 goto out_warn_father;
 531         }
 532
 533         /* ask father to setup cgroups and wait for him to finish */
 534         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
 535                 return -1;
 536
 537         if (apparmor_load(handler) < 0)
 538                 goto out_warn_father;
 539
 540         if (lxc_seccomp_load(handler->conf) != 0)
 541                 goto out_warn_father;
 542
 543         if (run_lxc_hooks(handler->name, "start", handler->conf, handler->lxcpath, NULL)) {
 544                 ERROR("failed to run start hooks for container '%s'.", handler->name);
 545                 goto out_warn_father;
 546         }
 547
 548         /* The clearenv() and putenv() calls have been moved here
 549          * to allow us to use enviroment variables passed to the various
 550          * hooks, such as the start hook above.  Not all of the
 551          * variables like CONFIG_PATH or ROOTFS are valid in this
 552          * context but others are. */
 553         if (clearenv()) {
 554                 SYSERROR("failed to clear environment");
 555                 /* don't error out though */
 556         }
 557
 558         if (putenv("container=lxc")) {
 559                 SYSERROR("failed to set environment variable");
 560                 goto out_warn_father;
 561         }
 562
 563         close(handler->sigfd);
 564
 565         /* after this call, we are in error because this
 566          * ops should not return as it execs */
 567         handler->ops->start(handler, handler->data);
 568
 569 out_warn_father:
 570         /* we want the parent to know something went wrong, so any
 571          * value other than what it expects is ok. */
 572         lxc_sync_wake_parent(handler, LXC_SYNC_POST_CONFIGURE);
 573         return -1;
 574 }
 575
 576 int save_phys_nics(struct lxc_conf *conf)
 577 {
 578         struct lxc_list *iterator;
 579
 580         lxc_list_for_each(iterator, &conf->network) {
 581                 struct lxc_netdev *netdev = iterator->elem;
 582
 583                 if (netdev->type != LXC_NET_PHYS)
 584                         continue;
 585                 conf->saved_nics = realloc(conf->saved_nics,
 586                                 (conf->num_savednics+1)*sizeof(struct saved_nic));
 587                 if (!conf->saved_nics) {
 588                         SYSERROR("failed to allocate memory");
 589                         return -1;
 590                 }
 591                 conf->saved_nics[conf->num_savednics].ifindex = netdev->ifindex;
 592                 conf->saved_nics[conf->num_savednics].orig_name = strdup(netdev->link);
 593                 if (!conf->saved_nics[conf->num_savednics].orig_name) {
 594                         SYSERROR("failed to allocate memory");
 595                         return -1;
 596                 }
 597                 INFO("stored saved_nic #%d idx %d name %s\n", conf->num_savednics,
 598                         conf->saved_nics[conf->num_savednics].ifindex,
 599                         conf->saved_nics[conf->num_savednics].orig_name);
 600                 conf->num_savednics++;
 601         }
 602
 603         return 0;
 604 }
 605
 606 extern bool is_in_subcgroup(int pid, const char *subsystem, struct cgroup_desc *d);
 607 int lxc_spawn(struct lxc_handler *handler)
 608 {
 609         int failed_before_rename = 0;
 610         const char *name = handler->name;
 611
 612         if (lxc_sync_init(handler))
 613                 return -1;
 614
 615         handler->clone_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
 616         if (!lxc_list_empty(&handler->conf->id_map)) {
 617                 INFO("Cloning a new user namespace");
 618                 handler->clone_flags |= CLONE_NEWUSER;
 619         }
 620         if (!lxc_list_empty(&handler->conf->network)) {
 621
 622                 handler->clone_flags |= CLONE_NEWNET;
 623
 624                 /* Find gateway addresses from the link device, which is
 625                  * no longer accessible inside the container. Do this
 626                  * before creating network interfaces, since goto
 627                  * out_delete_net does not work before lxc_clone. */
 628                 if (lxc_find_gateway_addresses(handler)) {
 629                         ERROR("failed to find gateway addresses");
 630                         lxc_sync_fini(handler);
 631                         return -1;
 632                 }
 633
 634                 /* that should be done before the clone because we will
 635                  * fill the netdev index and use them in the child
 636                  */
 637                 if (lxc_create_network(handler)) {
 638                         ERROR("failed to create the network");
 639                         lxc_sync_fini(handler);
 640                         return -1;
 641                 }
 642         }
 643
 644         if (save_phys_nics(handler->conf)) {
 645                 ERROR("failed to save physical nic info");
 646                 goto out_abort;
 647         }
 648
 649         /*
 650          * if the rootfs is not a blockdev, prevent the container from
 651          * marking it readonly.
 652          */
 653
 654         handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
 655         if (handler->pinfd == -1) {
 656                 ERROR("failed to pin the container's rootfs");
 657                 goto out_delete_net;
 658         }
 659
 660         /* Create a process in a new set of namespaces */
 661         handler->pid = lxc_clone(do_start, handler, handler->clone_flags);
 662         if (handler->pid < 0) {
 663                 SYSERROR("failed to fork into a new namespace");
 664                 goto out_delete_net;
 665         }
 666
 667         lxc_sync_fini_child(handler);
 668
 669         if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE))
 670                 failed_before_rename = 1;
 671
 672         if ((handler->cgroup = lxc_cgroup_path_create(name)) == NULL)
 673                 goto out_delete_net;
 674
 675         if (setup_cgroup(handler, &handler->conf->cgroup)) {
 676                 ERROR("failed to setup the cgroups for '%s'", name);
 677                 goto out_delete_net;
 678         }
 679
 680         if (lxc_cgroup_enter(handler->cgroup, handler->pid) < 0)
 681                 goto out_delete_net;
 682
 683         if (failed_before_rename)
 684                 goto out_delete_net;
 685
 686         /* Create the network configuration */
 687         if (handler->clone_flags & CLONE_NEWNET) {
 688                 if (lxc_assign_network(&handler->conf->network, handler->pid)) {
 689                         ERROR("failed to create the configured network");
 690                         goto out_delete_net;
 691                 }
 692         }
 693
 694         /* map the container uids - the container became an invalid
 695          * userid the moment it was cloned with CLONE_NEWUSER - this
 696          * call doesn't change anything immediately, but allows the
 697          * container to setuid(0) (0 being mapped to something else on
 698          * the host) later to become a valid uid again */
 699         if (lxc_map_ids(&handler->conf->id_map, handler->pid)) {
 700                 ERROR("failed to set up id mapping");
 701                 goto out_delete_net;
 702         }
 703
 704         /* Tell the child to continue its initialization.  we'll get
 705          * LXC_SYNC_CGROUP when it is ready for us to setup cgroups
 706          */
 707         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
 708                 goto out_delete_net;
 709
 710         if (setup_cgroup_devices(handler, &handler->conf->cgroup)) {
 711                 ERROR("failed to setup the devices cgroup for '%s'", name);
 712                 goto out_delete_net;
 713         }
 714
 715         /* Tell the child to complete its initialization and wait for
 716          * it to exec or return an error.  (the child will never
 717          * return LXC_SYNC_POST_CGROUP+1.  It will either close the
 718          * sync pipe, causing lxc_sync_barrier_child to return
 719          * success, or return a different value, causing us to error
 720          * out).
 721          */
 722         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
 723                 return -1;
 724
 725         if (detect_shared_rootfs())
 726                 umount2(handler->conf->rootfs.mount, MNT_DETACH);
 727
 728         /* If child is in a fresh user namespace, chown his ptys for
 729          * it */
 730         if (uid_shift_ttys(handler->pid, handler->conf))
 731                 DEBUG("Failed to chown ptys.\n");
 732
 733         if (handler->ops->post_start(handler, handler->data))
 734                 goto out_abort;
 735
 736         if (lxc_set_state(name, handler, RUNNING)) {
 737                 ERROR("failed to set state to %s",
 738                               lxc_state2str(RUNNING));
 739                 goto out_abort;
 740         }
 741
 742         lxc_sync_fini(handler);
 743
 744         return 0;
 745
 746 out_delete_net:
 747         if (handler->clone_flags & CLONE_NEWNET)
 748                 lxc_delete_network(handler);
 749 out_abort:
 750         lxc_abort(name, handler);
 751         lxc_sync_fini(handler);
 752         if (handler->pinfd >= 0) {
 753                 close(handler->pinfd);
 754                 handler->pinfd = -1;
 755         }
 756
 757         return -1;
 758 }
 759
 760 int __lxc_start(const char *name, struct lxc_conf *conf,
 761                 struct lxc_operations* ops, void *data, const char *lxcpath)
 762 {
 763         struct lxc_handler *handler;
 764         int err = -1;
 765         int status;
 766
 767         handler = lxc_init(name, conf, lxcpath);
 768         if (!handler) {
 769                 ERROR("failed to initialize the container");
 770                 return -1;
 771         }
 772         handler->ops = ops;
 773         handler->data = data;
 774
 775         if (must_drop_cap_sys_boot(handler->conf)) {
 776                 #if HAVE_SYS_CAPABILITY_H
 777                 DEBUG("Dropping cap_sys_boot\n");
 778                 #else
 779                 DEBUG("Can't drop cap_sys_boot as capabilities aren't supported\n");
 780                 #endif
 781         } else {
 782                 DEBUG("Not dropping cap_sys_boot or watching utmp\n");
 783                 handler->conf->need_utmp_watch = 0;
 784         }
 785
 786         err = lxc_spawn(handler);
 787         if (err) {
 788                 ERROR("failed to spawn '%s'", name);
 789                 goto out_fini_nonet;
 790         }
 791
 792         err = lxc_poll(name, handler);
 793         if (err) {
 794                 ERROR("mainloop exited with an error");
 795                 goto out_abort;
 796         }
 797
 798         while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
 799                 continue;
 800
 801         /*
 802          * If the child process exited but was not signaled,
 803          * it didn't call reboot.  This should mean it was an
 804          * lxc-execute which simply exited.  In any case, treat
 805          * it as a 'halt'
 806          */
 807         if (WIFSIGNALED(status)) {
 808                 switch(WTERMSIG(status)) {
 809                 case SIGINT: /* halt */
 810                         DEBUG("Container halting");
 811                         break;
 812                 case SIGHUP: /* reboot */
 813                         DEBUG("Container rebooting");
 814                         handler->conf->reboot = 1;
 815                         break;
 816                 default:
 817                         DEBUG("unknown exit status for init: %d\n", WTERMSIG(status));
 818                         break;
 819                 }
 820         }
 821
 822         lxc_rename_phys_nics_on_shutdown(handler->conf);
 823
 824         if (handler->pinfd >= 0) {
 825                 close(handler->pinfd);
 826                 handler->pinfd = -1;
 827         }
 828
 829         err =  lxc_error_set_and_log(handler->pid, status);
 830 out_fini:
 831         lxc_delete_network(handler);
 832
 833 out_fini_nonet:
 834         lxc_fini(name, handler);
 835         return err;
 836
 837 out_abort:
 838         lxc_abort(name, handler);
 839         goto out_fini;
 840 }
 841
 842 struct start_args {
 843         char *const *argv;
 844 };
 845
 846 static int start(struct lxc_handler *handler, void* data)
 847 {
 848         struct start_args *arg = data;
 849
 850         NOTICE("exec'ing '%s'", arg->argv[0]);
 851
 852         execvp(arg->argv[0], arg->argv);
 853         SYSERROR("failed to exec %s", arg->argv[0]);
 854         return 0;
 855 }
 856
 857 static int post_start(struct lxc_handler *handler, void* data)
 858 {
 859         struct start_args *arg = data;
 860
 861         NOTICE("'%s' started with pid '%d'", arg->argv[0], handler->pid);
 862         return 0;
 863 }
 864
 865 static struct lxc_operations start_ops = {
 866         .start = start,
 867         .post_start = post_start
 868 };
 869
 870 int lxc_start(const char *name, char *const argv[], struct lxc_conf *conf,
 871               const char *lxcpath)
 872 {
 873         struct start_args start_arg = {
 874                 .argv = argv,
 875         };
 876
 877         if (lxc_check_inherited(conf, -1))
 878                 return -1;
 879
 880         conf->need_utmp_watch = 1;
 881         return __lxc_start(name, conf, &start_ops, &start_arg, lxcpath);
 882 }