src/lxc/start.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #define _GNU_SOURCE
  25 #include "config.h"
  26
  27 #include <alloca.h>
  28 #include <dirent.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <grp.h>
  32 #include <poll.h>
  33 #include <signal.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38 #include <sys/file.h>
  39 #include <sys/mount.h>
  40 #include <sys/param.h>
  41 #include <sys/prctl.h>
  42 #include <sys/socket.h>
  43 #include <sys/stat.h>
  44 #include <sys/syscall.h>
  45 #include <sys/types.h>
  46 #include <sys/un.h>
  47 #include <sys/wait.h>
  48
  49 #if HAVE_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 "af_unix.h"
  58 #include "caps.h"
  59 #include "cgroup.h"
  60 #include "commands.h"
  61 #include "conf.h"
  62 #include "console.h"
  63 #include "error.h"
  64 #include "log.h"
  65 #include "lxclock.h"
  66 #include "lxcseccomp.h"
  67 #include "lxcutmp.h"
  68 #include "mainloop.h"
  69 #include "monitor.h"
  70 #include "namespace.h"
  71 #include "start.h"
  72 #include "sync.h"
  73 #include "utils.h"
  74 #include "bdev/bdev.h"
  75 #include "lsm/lsm.h"
  76
  77 lxc_log_define(lxc_start, lxc);
  78
  79 const struct ns_info ns_info[LXC_NS_MAX] = {
  80         [LXC_NS_MNT] = {"mnt", CLONE_NEWNS},
  81         [LXC_NS_PID] = {"pid", CLONE_NEWPID},
  82         [LXC_NS_UTS] = {"uts", CLONE_NEWUTS},
  83         [LXC_NS_IPC] = {"ipc", CLONE_NEWIPC},
  84         [LXC_NS_USER] = {"user", CLONE_NEWUSER},
  85         [LXC_NS_NET] = {"net", CLONE_NEWNET}
  86 };
  87
  88 extern void mod_all_rdeps(struct lxc_container *c, bool inc);
  89 static bool do_destroy_container(struct lxc_conf *conf);
  90 static int lxc_rmdir_onedev_wrapper(void *data);
  91 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
  92                                             const char *name);
  93
  94 static void print_top_failing_dir(const char *path)
  95 {
  96         size_t len = strlen(path);
  97         char *copy = alloca(len + 1), *p, *e, saved;
  98         strcpy(copy, path);
  99
 100         p = copy;
 101         e = copy + len;
 102         while (p < e) {
 103                 while (p < e && *p == '/')
 104                         p++;
 105                 while (p < e && *p != '/')
 106                         p++;
 107                 saved = *p;
 108                 *p = '\0';
 109                 if (access(copy, X_OK)) {
 110                         SYSERROR("could not access %s.  Please grant it 'x' " \
 111                               "access, or add an ACL for the container root.",
 112                               copy);
 113                         return;
 114                 }
 115                 *p = saved;
 116         }
 117 }
 118
 119 static void close_ns(int ns_fd[LXC_NS_MAX]) {
 120         int i;
 121
 122         for (i = 0; i < LXC_NS_MAX; i++) {
 123                 if (ns_fd[i] > -1) {
 124                         close(ns_fd[i]);
 125                         ns_fd[i] = -1;
 126                 }
 127         }
 128 }
 129
 130 /*
 131  * preserve_ns: open /proc/@pid/ns/@ns for each namespace specified
 132  * in clone_flags.
 133  * Return true on success, false on failure.  On failure, leave an error
 134  * message in *errmsg, which caller must free.
 135  */
 136 static bool preserve_ns(int ns_fd[LXC_NS_MAX], int clone_flags, pid_t pid,
 137                         char **errmsg)
 138 {
 139         int i, ret;
 140         char path[MAXPATHLEN];
 141
 142         for (i = 0; i < LXC_NS_MAX; i++)
 143                 ns_fd[i] = -1;
 144
 145         snprintf(path, MAXPATHLEN, "/proc/%d/ns", pid);
 146         if (access(path, X_OK)) {
 147                 if (asprintf(errmsg, "Kernel does not support setns.") == -1)
 148                         *errmsg = NULL;
 149                 return false;
 150         }
 151
 152         for (i = 0; i < LXC_NS_MAX; i++) {
 153                 if ((clone_flags & ns_info[i].clone_flag) == 0)
 154                         continue;
 155                 snprintf(path, MAXPATHLEN, "/proc/%d/ns/%s", pid,
 156                          ns_info[i].proc_name);
 157                 ns_fd[i] = open(path, O_RDONLY | O_CLOEXEC);
 158                 if (ns_fd[i] < 0)
 159                         goto error;
 160         }
 161
 162         return true;
 163
 164 error:
 165         if (errno == ENOENT) {
 166                 ret = asprintf(errmsg, "Kernel does not support setns for %s",
 167                         ns_info[i].proc_name);
 168         } else {
 169                 ret = asprintf(errmsg, "Failed to open %s: %s",
 170                         path, strerror(errno));
 171         }
 172         if (ret == -1)
 173                 *errmsg = NULL;
 174         close_ns(ns_fd);
 175         return false;
 176 }
 177
 178 static int attach_ns(const int ns_fd[LXC_NS_MAX]) {
 179         int i;
 180
 181         for (i = 0; i < LXC_NS_MAX; i++) {
 182                 if (ns_fd[i] < 0)
 183                         continue;
 184
 185                 if (setns(ns_fd[i], 0) != 0)
 186                         goto error;
 187         }
 188         return 0;
 189
 190 error:
 191         SYSERROR("failed to set namespace '%s'", ns_info[i].proc_name);
 192         return -1;
 193 }
 194
 195 static int match_fd(int fd)
 196 {
 197         return (fd == 0 || fd == 1 || fd == 2);
 198 }
 199
 200 /*
 201  * Check for any fds we need to close
 202  * * if fd_to_ignore != -1, then if we find that fd open we will ignore it.
 203  * * By default we warn about open fds we find.
 204  * * If closeall is true, we will close open fds.
 205  * * If lxc-start was passed "-C", then conf->close_all_fds will be true,
 206  *     in which case we also close all open fds.
 207  * * A daemonized container will always pass closeall=true.
 208  */
 209 int lxc_check_inherited(struct lxc_conf *conf, bool closeall, int fd_to_ignore)
 210 {
 211         struct dirent dirent, *direntp;
 212         int fd, fddir;
 213         DIR *dir;
 214
 215         if (conf && conf->close_all_fds)
 216                 closeall = true;
 217
 218 restart:
 219         dir = opendir("/proc/self/fd");
 220         if (!dir) {
 221                 WARN("failed to open directory: %m");
 222                 return -1;
 223         }
 224
 225         fddir = dirfd(dir);
 226
 227         while (!readdir_r(dir, &dirent, &direntp)) {
 228                 if (!direntp)
 229                         break;
 230
 231                 if (!strcmp(direntp->d_name, "."))
 232                         continue;
 233
 234                 if (!strcmp(direntp->d_name, ".."))
 235                         continue;
 236
 237                 fd = atoi(direntp->d_name);
 238
 239                 if (fd == fddir || fd == lxc_log_fd || fd == fd_to_ignore)
 240                         continue;
 241
 242                 if (current_config && fd == current_config->logfd)
 243                         continue;
 244
 245                 if (match_fd(fd))
 246                         continue;
 247
 248                 if (closeall) {
 249                         close(fd);
 250                         closedir(dir);
 251                         INFO("closed inherited fd %d", fd);
 252                         goto restart;
 253                 }
 254                 WARN("inherited fd %d", fd);
 255         }
 256
 257         closedir(dir); /* cannot fail */
 258         return 0;
 259 }
 260
 261 static int setup_signal_fd(sigset_t *oldmask)
 262 {
 263         sigset_t mask;
 264         int fd;
 265
 266         /* Block everything except serious error signals */
 267         if (sigfillset(&mask) ||
 268             sigdelset(&mask, SIGILL) ||
 269             sigdelset(&mask, SIGSEGV) ||
 270             sigdelset(&mask, SIGBUS) ||
 271             sigdelset(&mask, SIGWINCH) ||
 272             sigprocmask(SIG_BLOCK, &mask, oldmask)) {
 273                 SYSERROR("failed to set signal mask");
 274                 return -1;
 275         }
 276
 277         fd = signalfd(-1, &mask, 0);
 278         if (fd < 0) {
 279                 SYSERROR("failed to create the signal fd");
 280                 return -1;
 281         }
 282
 283         if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
 284                 SYSERROR("failed to set sigfd to close-on-exec");
 285                 close(fd);
 286                 return -1;
 287         }
 288
 289         DEBUG("sigchild handler set");
 290
 291         return fd;
 292 }
 293
 294 static int signal_handler(int fd, uint32_t events, void *data,
 295                           struct lxc_epoll_descr *descr)
 296 {
 297         struct signalfd_siginfo siginfo;
 298         siginfo_t info;
 299         int ret;
 300         pid_t *pid = data;
 301         bool init_died = false;
 302
 303         ret = read(fd, &siginfo, sizeof(siginfo));
 304         if (ret < 0) {
 305                 ERROR("failed to read signal info");
 306                 return -1;
 307         }
 308
 309         if (ret != sizeof(siginfo)) {
 310                 ERROR("unexpected siginfo size");
 311                 return -1;
 312         }
 313
 314         // check whether init is running
 315         info.si_pid = 0;
 316         ret = waitid(P_PID, *pid, &info, WEXITED | WNOWAIT | WNOHANG);
 317         if (ret == 0 && info.si_pid == *pid) {
 318                 init_died = true;
 319         }
 320
 321         if (siginfo.ssi_signo != SIGCHLD) {
 322                 kill(*pid, siginfo.ssi_signo);
 323                 INFO("forwarded signal %d to pid %d", siginfo.ssi_signo, *pid);
 324                 return init_died ? 1 : 0;
 325         }
 326
 327         if (siginfo.ssi_code == CLD_STOPPED ||
 328             siginfo.ssi_code == CLD_CONTINUED) {
 329                 INFO("container init process was stopped/continued");
 330                 return init_died ? 1 : 0;
 331         }
 332
 333         /* more robustness, protect ourself from a SIGCHLD sent
 334          * by a process different from the container init
 335          */
 336         if (siginfo.ssi_pid != *pid) {
 337                 WARN("invalid pid for SIGCHLD");
 338                 return init_died ? 1 : 0;
 339         }
 340
 341         DEBUG("container init process exited");
 342         return 1;
 343 }
 344
 345 int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
 346 {
 347         handler->state = state;
 348         lxc_monitor_send_state(name, state, handler->lxcpath);
 349         return 0;
 350 }
 351
 352 int lxc_poll(const char *name, struct lxc_handler *handler)
 353 {
 354         int sigfd = handler->sigfd;
 355         int pid = handler->pid;
 356         struct lxc_epoll_descr descr;
 357
 358         if (lxc_mainloop_open(&descr)) {
 359                 ERROR("failed to create mainloop");
 360                 goto out_sigfd;
 361         }
 362
 363         if (lxc_mainloop_add_handler(&descr, sigfd, signal_handler, &pid)) {
 364                 ERROR("failed to add handler for the signal");
 365                 goto out_mainloop_open;
 366         }
 367
 368         if (lxc_console_mainloop_add(&descr, handler->conf)) {
 369                 ERROR("failed to add console handler to mainloop");
 370                 goto out_mainloop_open;
 371         }
 372
 373         if (lxc_cmd_mainloop_add(name, &descr, handler)) {
 374                 ERROR("failed to add command handler to mainloop");
 375                 goto out_mainloop_open;
 376         }
 377
 378         if (handler->conf->need_utmp_watch) {
 379                 #if HAVE_SYS_CAPABILITY_H
 380                 if (lxc_utmp_mainloop_add(&descr, handler)) {
 381                         ERROR("failed to add utmp handler to mainloop");
 382                         goto out_mainloop_open;
 383                 }
 384                 #else
 385                         DEBUG("not starting utmp handler as cap_sys_boot cannot be dropped without capabilities support");
 386                 #endif
 387         }
 388
 389         return lxc_mainloop(&descr, -1);
 390
 391 out_mainloop_open:
 392         lxc_mainloop_close(&descr);
 393 out_sigfd:
 394         close(sigfd);
 395         return -1;
 396 }
 397
 398 struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char *lxcpath)
 399 {
 400         int i;
 401         struct lxc_handler *handler;
 402
 403         handler = malloc(sizeof(*handler));
 404         if (!handler)
 405                 return NULL;
 406
 407         memset(handler, 0, sizeof(*handler));
 408
 409         handler->ttysock[0] = handler->ttysock[1] = -1;
 410         handler->conf = conf;
 411         handler->lxcpath = lxcpath;
 412         handler->pinfd = -1;
 413
 414         for (i = 0; i < LXC_NS_MAX; i++)
 415                 handler->nsfd[i] = -1;
 416
 417         lsm_init();
 418
 419         handler->name = strdup(name);
 420         if (!handler->name) {
 421                 ERROR("failed to allocate memory");
 422                 goto out_free;
 423         }
 424
 425         if (lxc_cmd_init(name, handler, lxcpath))
 426                 goto out_free_name;
 427
 428         if (lxc_read_seccomp_config(conf) != 0) {
 429                 ERROR("failed loading seccomp policy");
 430                 goto out_close_maincmd_fd;
 431         }
 432
 433         /* Begin by setting the state to STARTING */
 434         if (lxc_set_state(name, handler, STARTING)) {
 435                 ERROR("failed to set state '%s'", lxc_state2str(STARTING));
 436                 goto out_close_maincmd_fd;
 437         }
 438
 439         /* Start of environment variable setup for hooks */
 440         if (name && setenv("LXC_NAME", name, 1)) {
 441                 SYSERROR("failed to set environment variable for container name");
 442         }
 443         if (conf->rcfile && setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
 444                 SYSERROR("failed to set environment variable for config path");
 445         }
 446         if (conf->rootfs.mount && setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
 447                 SYSERROR("failed to set environment variable for rootfs mount");
 448         }
 449         if (conf->rootfs.path && setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
 450                 SYSERROR("failed to set environment variable for rootfs mount");
 451         }
 452         if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
 453                 SYSERROR("failed to set environment variable for console path");
 454         }
 455         if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
 456                 SYSERROR("failed to set environment variable for console log");
 457         }
 458         if (setenv("LXC_CGNS_AWARE", "1", 1)) {
 459                 SYSERROR("failed to set LXC_CGNS_AWARE environment variable");
 460         }
 461         /* End of environment variable setup for hooks */
 462
 463         if (run_lxc_hooks(name, "pre-start", conf, handler->lxcpath, NULL)) {
 464                 ERROR("failed to run pre-start hooks for container '%s'.", name);
 465                 goto out_aborting;
 466         }
 467
 468         /* the signal fd has to be created before forking otherwise
 469          * if the child process exits before we setup the signal fd,
 470          * the event will be lost and the command will be stuck */
 471         handler->sigfd = setup_signal_fd(&handler->oldmask);
 472         if (handler->sigfd < 0) {
 473                 ERROR("failed to set sigchild fd handler");
 474                 goto out_delete_tty;
 475         }
 476
 477         /* do this after setting up signals since it might unblock SIGWINCH */
 478         if (lxc_console_create(conf)) {
 479                 ERROR("failed to create console");
 480                 goto out_restore_sigmask;
 481         }
 482
 483         if (ttys_shift_ids(conf) < 0) {
 484                 ERROR("Failed to shift tty into container");
 485                 goto out_restore_sigmask;
 486         }
 487
 488         INFO("'%s' is initialized", name);
 489         return handler;
 490
 491 out_restore_sigmask:
 492         sigprocmask(SIG_SETMASK, &handler->oldmask, NULL);
 493 out_delete_tty:
 494         lxc_delete_tty(&conf->tty_info);
 495 out_aborting:
 496         lxc_set_state(name, handler, ABORTING);
 497 out_close_maincmd_fd:
 498         close(conf->maincmd_fd);
 499         conf->maincmd_fd = -1;
 500 out_free_name:
 501         free(handler->name);
 502         handler->name = NULL;
 503 out_free:
 504         free(handler);
 505         return NULL;
 506 }
 507
 508 void lxc_fini(const char *name, struct lxc_handler *handler)
 509 {
 510         int i, rc;
 511         pid_t self = getpid();
 512         char *namespaces[LXC_NS_MAX+1];
 513         size_t namespace_count = 0;
 514
 515         /* The STOPPING state is there for future cleanup code
 516          * which can take awhile
 517          */
 518         lxc_set_state(name, handler, STOPPING);
 519
 520         for (i = 0; i < LXC_NS_MAX; i++) {
 521                 if (handler->nsfd[i] != -1) {
 522                         rc = asprintf(&namespaces[namespace_count], "%s:/proc/%d/fd/%d",
 523                                       ns_info[i].proc_name, self, handler->nsfd[i]);
 524                         if (rc == -1) {
 525                                 SYSERROR("failed to allocate memory");
 526                                 break;
 527                         }
 528                         ++namespace_count;
 529                 }
 530         }
 531         namespaces[namespace_count] = NULL;
 532
 533         if (handler->conf->reboot && setenv("LXC_TARGET", "reboot", 1)) {
 534                 SYSERROR("failed to set environment variable for stop target");
 535         }
 536         if (!handler->conf->reboot && setenv("LXC_TARGET", "stop", 1)) {
 537                 SYSERROR("failed to set environment variable for stop target");
 538         }
 539
 540         if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath, namespaces))
 541                 ERROR("failed to run stop hooks for container '%s'.", name);
 542
 543         while (namespace_count--)
 544                 free(namespaces[namespace_count]);
 545         for (i = 0; i < LXC_NS_MAX; i++) {
 546                 if (handler->nsfd[i] != -1) {
 547                         close(handler->nsfd[i]);
 548                         handler->nsfd[i] = -1;
 549                 }
 550         }
 551         lxc_set_state(name, handler, STOPPED);
 552
 553         if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL)) {
 554                 ERROR("failed to run post-stop hooks for container '%s'.", name);
 555                 if (handler->conf->reboot) {
 556                         WARN("Container will be stopped instead of rebooted.");
 557                         handler->conf->reboot = 0;
 558                         setenv("LXC_TARGET", "stop", 1);
 559                 }
 560         }
 561
 562         /* reset mask set by setup_signal_fd */
 563         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
 564                 WARN("failed to restore sigprocmask");
 565
 566         lxc_console_delete(&handler->conf->console);
 567         lxc_delete_tty(&handler->conf->tty_info);
 568         close(handler->conf->maincmd_fd);
 569         handler->conf->maincmd_fd = -1;
 570         free(handler->name);
 571         if (handler->ttysock[0] != -1) {
 572                 close(handler->ttysock[0]);
 573                 close(handler->ttysock[1]);
 574         }
 575
 576         if (handler->conf->ephemeral == 1 && handler->conf->reboot != 1)
 577                 lxc_destroy_container_on_signal(handler, name);
 578
 579         cgroup_destroy(handler);
 580         free(handler);
 581 }
 582
 583 void lxc_abort(const char *name, struct lxc_handler *handler)
 584 {
 585         int ret, status;
 586
 587         lxc_set_state(name, handler, ABORTING);
 588         if (handler->pid > 0)
 589                 kill(handler->pid, SIGKILL);
 590         while ((ret = waitpid(-1, &status, 0)) > 0) ;
 591 }
 592
 593 #include <sys/reboot.h>
 594 #include <linux/reboot.h>
 595
 596 /*
 597  * reboot(LINUX_REBOOT_CMD_CAD_ON) will return -EINVAL
 598  * in a child pid namespace if container reboot support exists.
 599  * Otherwise, it will either succeed or return -EPERM.
 600  */
 601 static int container_reboot_supported(void *arg)
 602 {
 603         int *cmd = arg;
 604         int ret;
 605
 606         ret = reboot(*cmd);
 607         if (ret == -1 && errno == EINVAL)
 608                 return 1;
 609         return 0;
 610 }
 611
 612 static int must_drop_cap_sys_boot(struct lxc_conf *conf)
 613 {
 614         FILE *f;
 615         int ret, cmd, v, flags;
 616         long stack_size = 4096;
 617         void *stack = alloca(stack_size);
 618         int status;
 619         pid_t pid;
 620
 621         f = fopen("/proc/sys/kernel/ctrl-alt-del", "r");
 622         if (!f) {
 623                 DEBUG("failed to open /proc/sys/kernel/ctrl-alt-del");
 624                 return 1;
 625         }
 626
 627         ret = fscanf(f, "%d", &v);
 628         fclose(f);
 629         if (ret != 1) {
 630                 DEBUG("Failed to read /proc/sys/kernel/ctrl-alt-del");
 631                 return 1;
 632         }
 633         cmd = v ? LINUX_REBOOT_CMD_CAD_ON : LINUX_REBOOT_CMD_CAD_OFF;
 634
 635         flags = CLONE_NEWPID | SIGCHLD;
 636         if (!lxc_list_empty(&conf->id_map))
 637                 flags |= CLONE_NEWUSER;
 638
 639 #ifdef __ia64__
 640         pid = __clone2(container_reboot_supported, stack, stack_size, flags,  &cmd);
 641 #else
 642         stack += stack_size;
 643         pid = clone(container_reboot_supported, stack, flags, &cmd);
 644 #endif
 645         if (pid < 0) {
 646                 if (flags & CLONE_NEWUSER)
 647                         ERROR("failed to clone (%#x): %s (includes CLONE_NEWUSER)", flags, strerror(errno));
 648                 else
 649                         ERROR("failed to clone (%#x): %s", flags, strerror(errno));
 650                 return -1;
 651         }
 652         if (wait(&status) < 0) {
 653                 SYSERROR("unexpected wait error: %m");
 654                 return -1;
 655         }
 656
 657         if (WEXITSTATUS(status) != 1)
 658                 return 1;
 659
 660         return 0;
 661 }
 662
 663 /*
 664  * netpipe is used in the unprivileged case to transfer the ifindexes
 665  * from parent to child
 666  */
 667 static int netpipe = -1;
 668
 669 static inline int count_veths(struct lxc_list *network)
 670 {
 671         struct lxc_list *iterator;
 672         struct lxc_netdev *netdev;
 673         int count = 0;
 674
 675         lxc_list_for_each(iterator, network) {
 676                 netdev = iterator->elem;
 677                 if (netdev->type != LXC_NET_VETH)
 678                         continue;
 679                 count++;
 680         }
 681         return count;
 682 }
 683
 684 static int read_unpriv_netifindex(struct lxc_list *network)
 685 {
 686         struct lxc_list *iterator;
 687         struct lxc_netdev *netdev;
 688
 689         if (netpipe == -1)
 690                 return 0;
 691         lxc_list_for_each(iterator, network) {
 692                 netdev = iterator->elem;
 693                 if (netdev->type != LXC_NET_VETH)
 694                         continue;
 695                 if (!(netdev->name = malloc(IFNAMSIZ))) {
 696                         ERROR("Out of memory");
 697                         close(netpipe);
 698                         return -1;
 699                 }
 700                 if (read(netpipe, netdev->name, IFNAMSIZ) != IFNAMSIZ) {
 701                         close(netpipe);
 702                         return -1;
 703                 }
 704         }
 705         close(netpipe);
 706         return 0;
 707 }
 708
 709 static int do_start(void *data)
 710 {
 711         struct lxc_list *iterator;
 712         struct lxc_handler *handler = data;
 713         int devnull_fd = -1, ret;
 714         char path[PATH_MAX];
 715
 716         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL)) {
 717                 SYSERROR("failed to set sigprocmask");
 718                 return -1;
 719         }
 720
 721         /* This prctl must be before the synchro, so if the parent
 722          * dies before we set the parent death signal, we will detect
 723          * its death with the synchro right after, otherwise we have
 724          * a window where the parent can exit before we set the pdeath
 725          * signal leading to a unsupervized container.
 726          */
 727         if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0)) {
 728                 SYSERROR("failed to set pdeath signal");
 729                 return -1;
 730         }
 731
 732         lxc_sync_fini_parent(handler);
 733
 734         /* don't leak the pinfd to the container */
 735         if (handler->pinfd >= 0) {
 736                 close(handler->pinfd);
 737         }
 738
 739         if (lxc_sync_wait_parent(handler, LXC_SYNC_STARTUP))
 740                 return -1;
 741
 742         /* Unshare CLONE_NEWNET after CLONE_NEWUSER  - see
 743           https://github.com/lxc/lxd/issues/1978 */
 744         if ((handler->clone_flags & (CLONE_NEWNET | CLONE_NEWUSER)) ==
 745                         (CLONE_NEWNET | CLONE_NEWUSER)) {
 746                 ret = unshare(CLONE_NEWNET);
 747                 if (ret < 0) {
 748                         SYSERROR("Error unsharing network namespace");
 749                         goto out_warn_father;
 750                 }
 751         }
 752
 753         /* Tell the parent task it can begin to configure the
 754          * container and wait for it to finish
 755          */
 756         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
 757                 return -1;
 758
 759         if (read_unpriv_netifindex(&handler->conf->network) < 0)
 760                 goto out_warn_father;
 761
 762         /*
 763          * if we are in a new user namespace, become root there to have
 764          * privilege over our namespace. When using lxc-execute we default to root,
 765          * but this can be overriden using the lxc.init_uid and lxc.init_gid
 766          * configuration options.
 767          */
 768         if (!lxc_list_empty(&handler->conf->id_map)) {
 769                 gid_t new_gid = 0;
 770                 if (handler->conf->is_execute && handler->conf->init_gid)
 771                         new_gid = handler->conf->init_gid;
 772
 773                 uid_t new_uid = 0;
 774                 if (handler->conf->is_execute && handler->conf->init_uid)
 775                         new_uid = handler->conf->init_uid;
 776
 777                 NOTICE("switching to gid/uid %d/%d in new user namespace", new_gid, new_uid);
 778                 if (setgid(new_gid)) {
 779                         SYSERROR("setgid");
 780                         goto out_warn_father;
 781                 }
 782                 if (setuid(new_uid)) {
 783                         SYSERROR("setuid");
 784                         goto out_warn_father;
 785                 }
 786                 if (setgroups(0, NULL)) {
 787                         SYSERROR("setgroups");
 788                         goto out_warn_father;
 789                 }
 790         }
 791
 792         if (access(handler->lxcpath, X_OK)) {
 793                 print_top_failing_dir(handler->lxcpath);
 794                 goto out_warn_father;
 795         }
 796
 797         #if HAVE_SYS_CAPABILITY_H
 798         if (handler->conf->need_utmp_watch) {
 799                 if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
 800                         SYSERROR("failed to remove CAP_SYS_BOOT capability");
 801                         goto out_warn_father;
 802                 }
 803                 DEBUG("Dropped cap_sys_boot");
 804         }
 805         #endif
 806
 807         ret = snprintf(path, sizeof(path), "%s/dev/null", handler->conf->rootfs.mount);
 808         if (ret < 0 || ret >= sizeof(path)) {
 809                 SYSERROR("sprintf'd too many chars");
 810                 goto out_warn_father;
 811         }
 812
 813         /* In order to checkpoint restore, we need to have everything in the
 814          * same mount namespace. However, some containers may not have a
 815          * reasonable /dev (in particular, they may not have /dev/null), so we
 816          * can't set init's std fds to /dev/null by opening it from inside the
 817          * container.
 818          *
 819          * If that's the case, fall back to using the host's /dev/null. This
 820          * means that migration won't work, but at least we won't spew output
 821          * where it isn't wanted.
 822          */
 823         if (handler->backgrounded && !handler->conf->autodev && access(path, F_OK) < 0) {
 824                 devnull_fd = open_devnull();
 825
 826                 if (devnull_fd < 0)
 827                         goto out_warn_father;
 828                 WARN("using host's /dev/null for container init's std fds, migraiton won't work");
 829         }
 830
 831         /* Setup the container, ip, names, utsname, ... */
 832         if (lxc_setup(handler)) {
 833                 ERROR("failed to setup the container");
 834                 goto out_warn_father;
 835         }
 836
 837         /* ask father to setup cgroups and wait for him to finish */
 838         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
 839                 goto out_error;
 840
 841         /* Set the label to change to when we exec(2) the container's init */
 842         if (lsm_process_label_set(NULL, handler->conf, 1, 1) < 0)
 843                 goto out_warn_father;
 844
 845         /* Some init's such as busybox will set sane tty settings on stdin,
 846          * stdout, stderr which it thinks is the console. We already set them
 847          * the way we wanted on the real terminal, and we want init to do its
 848          * setup on its console ie. the pty allocated in lxc_console_create()
 849          * so make sure that that pty is stdin,stdout,stderr.
 850          */
 851         if (lxc_console_set_stdfds(handler->conf->console.slave) < 0)
 852                 goto out_warn_father;
 853
 854         /* If we mounted a temporary proc, then unmount it now */
 855         tmp_proc_unmount(handler->conf);
 856
 857         if (lxc_seccomp_load(handler->conf) != 0)
 858                 goto out_warn_father;
 859
 860         if (run_lxc_hooks(handler->name, "start", handler->conf, handler->lxcpath, NULL)) {
 861                 ERROR("failed to run start hooks for container '%s'.", handler->name);
 862                 goto out_warn_father;
 863         }
 864
 865         /* The clearenv() and putenv() calls have been moved here
 866          * to allow us to use environment variables passed to the various
 867          * hooks, such as the start hook above.  Not all of the
 868          * variables like CONFIG_PATH or ROOTFS are valid in this
 869          * context but others are. */
 870         if (clearenv()) {
 871                 SYSERROR("failed to clear environment");
 872                 /* don't error out though */
 873         }
 874
 875         lxc_list_for_each(iterator, &handler->conf->environment) {
 876                 if (putenv((char *)iterator->elem)) {
 877                         SYSERROR("failed to set environment variable '%s'", (char *)iterator->elem);
 878                         goto out_warn_father;
 879                 }
 880         }
 881
 882         if (putenv("container=lxc")) {
 883                 SYSERROR("failed to set environment variable 'container=lxc'");
 884                 goto out_warn_father;
 885         }
 886
 887         if (handler->conf->pty_names) {
 888                 if (putenv(handler->conf->pty_names)) {
 889                         SYSERROR("failed to set environment variable for container ptys");
 890                         goto out_warn_father;
 891                 }
 892         }
 893
 894         close(handler->sigfd);
 895
 896         if (devnull_fd < 0) {
 897                 devnull_fd = open_devnull();
 898
 899                 if (devnull_fd < 0)
 900                         goto out_warn_father;
 901         }
 902
 903         if (handler->backgrounded && set_stdfds(devnull_fd))
 904                 goto out_warn_father;
 905
 906         if (devnull_fd >= 0) {
 907                 close(devnull_fd);
 908                 devnull_fd = -1;
 909         }
 910
 911         if (cgns_supported() && unshare(CLONE_NEWCGROUP) != 0) {
 912                 SYSERROR("Failed to unshare cgroup namespace");
 913                 goto out_warn_father;
 914         }
 915
 916         setsid();
 917
 918         /* after this call, we are in error because this
 919          * ops should not return as it execs */
 920         handler->ops->start(handler, handler->data);
 921
 922 out_warn_father:
 923         /* we want the parent to know something went wrong, so we return a special
 924          * error code. */
 925         lxc_sync_wake_parent(handler, LXC_SYNC_ERROR);
 926
 927 out_error:
 928         if (devnull_fd >= 0)
 929                 close(devnull_fd);
 930
 931         return -1;
 932 }
 933
 934 static int save_phys_nics(struct lxc_conf *conf)
 935 {
 936         struct lxc_list *iterator;
 937         int am_root = (getuid() == 0);
 938
 939         if (!am_root)
 940                 return 0;
 941
 942         lxc_list_for_each(iterator, &conf->network) {
 943                 struct lxc_netdev *netdev = iterator->elem;
 944
 945                 if (netdev->type != LXC_NET_PHYS)
 946                         continue;
 947                 conf->saved_nics = realloc(conf->saved_nics,
 948                                 (conf->num_savednics+1)*sizeof(struct saved_nic));
 949                 if (!conf->saved_nics) {
 950                         SYSERROR("failed to allocate memory");
 951                         return -1;
 952                 }
 953                 conf->saved_nics[conf->num_savednics].ifindex = netdev->ifindex;
 954                 conf->saved_nics[conf->num_savednics].orig_name = strdup(netdev->link);
 955                 if (!conf->saved_nics[conf->num_savednics].orig_name) {
 956                         SYSERROR("failed to allocate memory");
 957                         return -1;
 958                 }
 959                 INFO("stored saved_nic #%d idx %d name %s", conf->num_savednics,
 960                         conf->saved_nics[conf->num_savednics].ifindex,
 961                         conf->saved_nics[conf->num_savednics].orig_name);
 962                 conf->num_savednics++;
 963         }
 964
 965         return 0;
 966 }
 967
 968 static int recv_fd(int sock, int *fd)
 969 {
 970         if (lxc_abstract_unix_recv_fd(sock, fd, NULL, 0) < 0) {
 971                 SYSERROR("Error receiving tty fd from child");
 972                 return -1;
 973         }
 974         if (*fd == -1)
 975                 return -1;
 976         return 0;
 977 }
 978
 979 static int recv_ttys_from_child(struct lxc_handler *handler)
 980 {
 981         struct lxc_conf *conf = handler->conf;
 982         int i, sock = handler->ttysock[1];
 983         struct lxc_tty_info *tty_info = &conf->tty_info;
 984
 985         if (!conf->tty)
 986                 return 0;
 987
 988         tty_info->pty_info = malloc(sizeof(*tty_info->pty_info)*conf->tty);
 989         if (!tty_info->pty_info) {
 990                 SYSERROR("failed to allocate pty_info");
 991                 return -1;
 992         }
 993
 994         for (i = 0; i < conf->tty; i++) {
 995                 struct lxc_pty_info *pty_info = &tty_info->pty_info[i];
 996                 pty_info->busy = 0;
 997                 if (recv_fd(sock, &pty_info->slave) < 0 ||
 998                                 recv_fd(sock, &pty_info->master) < 0) {
 999                         ERROR("Error receiving tty info from child");
1000                         return -1;
1001                 }
1002         }
1003         tty_info->nbtty = conf->tty;
1004
1005         return 0;
1006 }
1007
1008 void resolve_clone_flags(struct lxc_handler *handler)
1009 {
1010         handler->clone_flags = CLONE_NEWPID | CLONE_NEWNS;
1011
1012         if (!lxc_list_empty(&handler->conf->id_map)) {
1013                 INFO("Cloning a new user namespace");
1014                 handler->clone_flags |= CLONE_NEWUSER;
1015         }
1016
1017         if (handler->conf->inherit_ns_fd[LXC_NS_NET] == -1) {
1018                 if (!lxc_requests_empty_network(handler))
1019                         handler->clone_flags |= CLONE_NEWNET;
1020         } else {
1021                 INFO("Inheriting a net namespace");
1022         }
1023
1024         if (handler->conf->inherit_ns_fd[LXC_NS_IPC] == -1) {
1025                 handler->clone_flags |= CLONE_NEWIPC;
1026         } else {
1027                 INFO("Inheriting an IPC namespace");
1028         }
1029
1030         if (handler->conf->inherit_ns_fd[LXC_NS_UTS] == -1) {
1031                 handler->clone_flags |= CLONE_NEWUTS;
1032         } else {
1033                 INFO("Inheriting a UTS namespace");
1034         }
1035 }
1036
1037 static int lxc_spawn(struct lxc_handler *handler)
1038 {
1039         int failed_before_rename = 0;
1040         const char *name = handler->name;
1041         char *errmsg = NULL;
1042         bool cgroups_connected = false;
1043         int saved_ns_fd[LXC_NS_MAX];
1044         int preserve_mask = 0, i, flags;
1045         int netpipepair[2], nveths;
1046
1047         netpipe = -1;
1048
1049         for (i = 0; i < LXC_NS_MAX; i++)
1050                 if (handler->conf->inherit_ns_fd[i] != -1)
1051                         preserve_mask |= ns_info[i].clone_flag;
1052
1053         if (lxc_sync_init(handler))
1054                 return -1;
1055
1056         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, handler->ttysock) < 0) {
1057                 lxc_sync_fini(handler);
1058                 return -1;
1059         }
1060
1061         resolve_clone_flags(handler);
1062
1063         if (handler->clone_flags & CLONE_NEWNET) {
1064                 if (!lxc_list_empty(&handler->conf->network)) {
1065
1066                         /* Find gateway addresses from the link device, which is
1067                          * no longer accessible inside the container. Do this
1068                          * before creating network interfaces, since goto
1069                          * out_delete_net does not work before lxc_clone. */
1070                         if (lxc_find_gateway_addresses(handler)) {
1071                                 ERROR("failed to find gateway addresses");
1072                                 lxc_sync_fini(handler);
1073                                 return -1;
1074                         }
1075
1076                         /* that should be done before the clone because we will
1077                          * fill the netdev index and use them in the child
1078                          */
1079                         if (lxc_create_network(handler)) {
1080                                 ERROR("failed to create the network");
1081                                 lxc_sync_fini(handler);
1082                                 return -1;
1083                         }
1084                 }
1085
1086                 if (save_phys_nics(handler->conf)) {
1087                         ERROR("failed to save physical nic info");
1088                         goto out_abort;
1089                 }
1090         }
1091
1092         if (!cgroup_init(handler)) {
1093                 ERROR("failed initializing cgroup support");
1094                 goto out_delete_net;
1095         }
1096
1097         cgroups_connected = true;
1098
1099         if (!cgroup_create(handler)) {
1100                 ERROR("failed creating cgroups");
1101                 goto out_delete_net;
1102         }
1103
1104         /*
1105          * if the rootfs is not a blockdev, prevent the container from
1106          * marking it readonly.
1107          *
1108          * if the container is unprivileged then skip rootfs pinning
1109          */
1110         if (lxc_list_empty(&handler->conf->id_map)) {
1111                 handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
1112                 if (handler->pinfd == -1)
1113                         INFO("failed to pin the container's rootfs");
1114         }
1115
1116         if (!preserve_ns(saved_ns_fd, preserve_mask, getpid(), &errmsg)) {
1117                 SYSERROR("Failed to preserve requested namespaces: %s",
1118                         errmsg ? errmsg : "(Out of memory)");
1119                 free(errmsg);
1120                 goto out_delete_net;
1121         }
1122         if (attach_ns(handler->conf->inherit_ns_fd) < 0)
1123                 goto out_delete_net;
1124
1125         if (am_unpriv() && (nveths = count_veths(&handler->conf->network))) {
1126                 if (pipe(netpipepair) < 0) {
1127                         SYSERROR("Error creating pipe");
1128                         goto out_delete_net;
1129                 }
1130                 /* store netpipe in the global var for do_start's use */
1131                 netpipe = netpipepair[0];
1132         }
1133
1134         /* Create a process in a new set of namespaces */
1135         flags = handler->clone_flags;
1136         if (handler->clone_flags & CLONE_NEWUSER)
1137                 flags &= ~CLONE_NEWNET;
1138         handler->pid = lxc_clone(do_start, handler, handler->clone_flags);
1139         if (handler->pid < 0) {
1140                 SYSERROR("failed to fork into a new namespace");
1141                 goto out_delete_net;
1142         }
1143
1144         if (!preserve_ns(handler->nsfd, handler->clone_flags | preserve_mask, handler->pid, &errmsg)) {
1145                 INFO("Failed to store namespace references for stop hook: %s",
1146                         errmsg ? errmsg : "(Out of memory)");
1147                 free(errmsg);
1148         }
1149
1150         if (attach_ns(saved_ns_fd))
1151                 WARN("failed to restore saved namespaces");
1152
1153         lxc_sync_fini_child(handler);
1154
1155         /* map the container uids - the container became an invalid
1156          * userid the moment it was cloned with CLONE_NEWUSER - this
1157          * call doesn't change anything immediately, but allows the
1158          * container to setuid(0) (0 being mapped to something else on
1159          * the host) later to become a valid uid again */
1160         if (lxc_map_ids(&handler->conf->id_map, handler->pid)) {
1161                 ERROR("failed to set up id mapping");
1162                 goto out_delete_net;
1163         }
1164
1165         if (lxc_sync_wake_child(handler, LXC_SYNC_STARTUP)) {
1166                 failed_before_rename = 1;
1167                 goto out_delete_net;
1168         }
1169
1170         if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE)) {
1171                 failed_before_rename = 1;
1172                 goto out_delete_net;
1173         }
1174
1175         if (!cgroup_create_legacy(handler)) {
1176                 ERROR("failed to setup the legacy cgroups for %s", name);
1177                 goto out_delete_net;
1178         }
1179         if (!cgroup_setup_limits(handler, false)) {
1180                 ERROR("failed to setup the cgroup limits for '%s'", name);
1181                 goto out_delete_net;
1182         }
1183
1184         if (!cgroup_enter(handler))
1185                 goto out_delete_net;
1186
1187         if (!cgroup_chown(handler))
1188                 goto out_delete_net;
1189
1190         if (failed_before_rename)
1191                 goto out_delete_net;
1192
1193         /* Create the network configuration */
1194         if (handler->clone_flags & CLONE_NEWNET) {
1195                 if (lxc_assign_network(handler->lxcpath, handler->name,
1196                                         &handler->conf->network, handler->pid)) {
1197                         ERROR("failed to create the configured network");
1198                         goto out_delete_net;
1199                 }
1200         }
1201
1202         if (netpipe != -1) {
1203                 struct lxc_list *iterator;
1204                 struct lxc_netdev *netdev;
1205
1206                 close(netpipe);
1207                 lxc_list_for_each(iterator, &handler->conf->network) {
1208                         netdev = iterator->elem;
1209                         if (netdev->type != LXC_NET_VETH)
1210                                 continue;
1211                         if (write(netpipepair[1], netdev->name, IFNAMSIZ) != IFNAMSIZ) {
1212                                 ERROR("Error writing veth name to container");
1213                                 goto out_delete_net;
1214                         }
1215                 }
1216                 close(netpipepair[1]);
1217         }
1218
1219         /* Tell the child to continue its initialization.  we'll get
1220          * LXC_SYNC_CGROUP when it is ready for us to setup cgroups
1221          */
1222         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
1223                 goto out_delete_net;
1224
1225         if (!cgroup_setup_limits(handler, true)) {
1226                 ERROR("failed to setup the devices cgroup for '%s'", name);
1227                 goto out_delete_net;
1228         }
1229
1230         cgroup_disconnect();
1231         cgroups_connected = false;
1232
1233         /* read tty fds allocated by child */
1234         if (recv_ttys_from_child(handler) < 0) {
1235                 ERROR("failed to receive tty info from child");
1236                 goto out_delete_net;
1237         }
1238
1239         /* Tell the child to complete its initialization and wait for
1240          * it to exec or return an error.  (the child will never
1241          * return LXC_SYNC_POST_CGROUP+1.  It will either close the
1242          * sync pipe, causing lxc_sync_barrier_child to return
1243          * success, or return a different value, causing us to error
1244          * out).
1245          */
1246         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
1247                 return -1;
1248
1249         if (detect_shared_rootfs())
1250                 umount2(handler->conf->rootfs.mount, MNT_DETACH);
1251
1252         if (handler->ops->post_start(handler, handler->data))
1253                 goto out_abort;
1254
1255         if (lxc_set_state(name, handler, RUNNING)) {
1256                 ERROR("failed to set state to %s",
1257                               lxc_state2str(RUNNING));
1258                 goto out_abort;
1259         }
1260
1261         lxc_sync_fini(handler);
1262
1263         return 0;
1264
1265 out_delete_net:
1266         if (cgroups_connected)
1267                 cgroup_disconnect();
1268         if (handler->clone_flags & CLONE_NEWNET)
1269                 lxc_delete_network(handler);
1270 out_abort:
1271         lxc_abort(name, handler);
1272         lxc_sync_fini(handler);
1273         if (handler->pinfd >= 0) {
1274                 close(handler->pinfd);
1275                 handler->pinfd = -1;
1276         }
1277
1278         return -1;
1279 }
1280
1281 int get_netns_fd(int pid)
1282 {
1283         char path[MAXPATHLEN];
1284         int ret, fd;
1285
1286         ret = snprintf(path, MAXPATHLEN, "/proc/%d/ns/net", pid);
1287         if (ret < 0 || ret >= MAXPATHLEN) {
1288                 WARN("Failed to pin netns file for pid %d", pid);
1289                 return -1;
1290         }
1291
1292         fd = open(path, O_RDONLY);
1293         if (fd < 0) {
1294                 WARN("Failed to pin netns file %s for pid %d: %s",
1295                                 path, pid, strerror(errno));
1296                 return -1;
1297         }
1298         return fd;
1299 }
1300
1301 int __lxc_start(const char *name, struct lxc_conf *conf,
1302                 struct lxc_operations* ops, void *data, const char *lxcpath,
1303                 bool backgrounded)
1304 {
1305         struct lxc_handler *handler;
1306         int err = -1;
1307         int status;
1308         int netnsfd = -1;
1309
1310         handler = lxc_init(name, conf, lxcpath);
1311         if (!handler) {
1312                 ERROR("failed to initialize the container");
1313                 return -1;
1314         }
1315         handler->ops = ops;
1316         handler->data = data;
1317         handler->backgrounded = backgrounded;
1318
1319         if (must_drop_cap_sys_boot(handler->conf)) {
1320                 #if HAVE_SYS_CAPABILITY_H
1321                 DEBUG("Dropping cap_sys_boot");
1322                 #else
1323                 DEBUG("Can't drop cap_sys_boot as capabilities aren't supported");
1324                 #endif
1325         } else {
1326                 DEBUG("Not dropping cap_sys_boot or watching utmp");
1327                 handler->conf->need_utmp_watch = 0;
1328         }
1329
1330         if (!attach_block_device(handler->conf)) {
1331                 ERROR("Failure attaching block device");
1332                 goto out_fini_nonet;
1333         }
1334
1335         if (geteuid() == 0 && !lxc_list_empty(&conf->id_map)) {
1336                 /* if the backing store is a device, mount it here and now */
1337                 if (rootfs_is_blockdev(conf)) {
1338                         if (unshare(CLONE_NEWNS) < 0) {
1339                                 ERROR("Error unsharing mounts");
1340                                 goto out_fini_nonet;
1341                         }
1342                         remount_all_slave();
1343                         if (do_rootfs_setup(conf, name, lxcpath) < 0) {
1344                                 ERROR("Error setting up rootfs mount as root before spawn");
1345                                 goto out_fini_nonet;
1346                         }
1347                         INFO("Set up container rootfs as host root");
1348                 }
1349         }
1350
1351         err = lxc_spawn(handler);
1352         if (err) {
1353                 ERROR("failed to spawn '%s'", name);
1354                 goto out_detach_blockdev;
1355         }
1356
1357         handler->conf->reboot = 0;
1358
1359         netnsfd = get_netns_fd(handler->pid);
1360
1361         err = lxc_poll(name, handler);
1362         if (err) {
1363                 ERROR("mainloop exited with an error");
1364                 if (netnsfd >= 0)
1365                         close(netnsfd);
1366                 goto out_abort;
1367         }
1368
1369         while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
1370                 continue;
1371
1372         /*
1373          * If the child process exited but was not signaled,
1374          * it didn't call reboot.  This should mean it was an
1375          * lxc-execute which simply exited.  In any case, treat
1376          * it as a 'halt'
1377          */
1378         if (WIFSIGNALED(status)) {
1379                 switch(WTERMSIG(status)) {
1380                 case SIGINT: /* halt */
1381                         DEBUG("Container halting");
1382                         break;
1383                 case SIGHUP: /* reboot */
1384                         DEBUG("Container rebooting");
1385                         handler->conf->reboot = 1;
1386                         break;
1387                 case SIGSYS: /* seccomp */
1388                         DEBUG("Container violated its seccomp policy");
1389                         break;
1390                 default:
1391                         DEBUG("unknown exit status for init: %d", WTERMSIG(status));
1392                         break;
1393                 }
1394         }
1395
1396         DEBUG("Pushing physical nics back to host namespace");
1397         lxc_rename_phys_nics_on_shutdown(netnsfd, handler->conf);
1398
1399         DEBUG("Tearing down virtual network devices used by container");
1400         lxc_delete_network(handler);
1401
1402         if (netnsfd >= 0)
1403                 close(netnsfd);
1404
1405         if (handler->pinfd >= 0) {
1406                 close(handler->pinfd);
1407                 handler->pinfd = -1;
1408         }
1409
1410         lxc_monitor_send_exit_code(name, status, handler->lxcpath);
1411         err =  lxc_error_set_and_log(handler->pid, status);
1412 out_fini:
1413         lxc_delete_network(handler);
1414
1415 out_detach_blockdev:
1416         detach_block_device(handler->conf);
1417
1418 out_fini_nonet:
1419         lxc_fini(name, handler);
1420         return err;
1421
1422 out_abort:
1423         lxc_abort(name, handler);
1424         goto out_fini;
1425 }
1426
1427 struct start_args {
1428         char *const *argv;
1429 };
1430
1431 static int start(struct lxc_handler *handler, void* data)
1432 {
1433         struct start_args *arg = data;
1434
1435         NOTICE("exec'ing '%s'", arg->argv[0]);
1436
1437         execvp(arg->argv[0], arg->argv);
1438         SYSERROR("failed to exec %s", arg->argv[0]);
1439         return 0;
1440 }
1441
1442 static int post_start(struct lxc_handler *handler, void* data)
1443 {
1444         struct start_args *arg = data;
1445
1446         NOTICE("'%s' started with pid '%d'", arg->argv[0], handler->pid);
1447         return 0;
1448 }
1449
1450 static struct lxc_operations start_ops = {
1451         .start = start,
1452         .post_start = post_start
1453 };
1454
1455 int lxc_start(const char *name, char *const argv[], struct lxc_conf *conf,
1456               const char *lxcpath, bool backgrounded)
1457 {
1458         struct start_args start_arg = {
1459                 .argv = argv,
1460         };
1461
1462         conf->need_utmp_watch = 1;
1463         return __lxc_start(name, conf, &start_ops, &start_arg, lxcpath, backgrounded);
1464 }
1465
1466 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
1467                                             const char *name)
1468 {
1469         char destroy[MAXPATHLEN];
1470         bool bret = true;
1471         int ret = 0;
1472         struct lxc_container *c;
1473         if (handler->conf->rootfs.path && handler->conf->rootfs.mount) {
1474                 bret = do_destroy_container(handler->conf);
1475                 if (!bret) {
1476                         ERROR("Error destroying rootfs for %s", name);
1477                         return;
1478                 }
1479         }
1480         INFO("Destroyed rootfs for %s", name);
1481
1482         ret = snprintf(destroy, MAXPATHLEN, "%s/%s", handler->lxcpath, name);
1483         if (ret < 0 || ret >= MAXPATHLEN) {
1484                 ERROR("Error printing path for %s", name);
1485                 ERROR("Error destroying directory for %s", name);
1486                 return;
1487         }
1488
1489         c = lxc_container_new(name, handler->lxcpath);
1490         if (c) {
1491                 if (container_disk_lock(c)) {
1492                         INFO("Could not update lxc_snapshots file");
1493                         lxc_container_put(c);
1494                 } else {
1495                         mod_all_rdeps(c, false);
1496                         container_disk_unlock(c);
1497                         lxc_container_put(c);
1498                 }
1499         }
1500
1501         if (am_unpriv())
1502                 ret = userns_exec_1(handler->conf, lxc_rmdir_onedev_wrapper, destroy);
1503         else
1504                 ret = lxc_rmdir_onedev(destroy, NULL);
1505
1506         if (ret < 0) {
1507                 ERROR("Error destroying directory for %s", name);
1508                 return;
1509         }
1510         INFO("Destroyed directory for %s", name);
1511 }
1512
1513 static int lxc_rmdir_onedev_wrapper(void *data)
1514 {
1515         char *arg = (char *) data;
1516         return lxc_rmdir_onedev(arg, NULL);
1517 }
1518
1519 static bool do_destroy_container(struct lxc_conf *conf) {
1520         if (am_unpriv()) {
1521                 if (userns_exec_1(conf, bdev_destroy_wrapper, conf) < 0)
1522                         return false;
1523                 return true;
1524         }
1525         return bdev_destroy(conf);
1526 }