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         [LXC_NS_CGROUP] = {"cgroup", CLONE_NEWCGROUP}
  87 };
  88
  89 extern void mod_all_rdeps(struct lxc_container *c, bool inc);
  90 static bool do_destroy_container(struct lxc_conf *conf);
  91 static int lxc_rmdir_onedev_wrapper(void *data);
  92 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
  93                                             const char *name);
  94
  95 static void print_top_failing_dir(const char *path)
  96 {
  97         size_t len = strlen(path);
  98         char *copy = alloca(len + 1), *p, *e, saved;
  99         strcpy(copy, path);
 100
 101         p = copy;
 102         e = copy + len;
 103         while (p < e) {
 104                 while (p < e && *p == '/')
 105                         p++;
 106                 while (p < e && *p != '/')
 107                         p++;
 108                 saved = *p;
 109                 *p = '\0';
 110                 if (access(copy, X_OK)) {
 111                         SYSERROR("could not access %s.  Please grant it 'x' " \
 112                               "access, or add an ACL for the container root.",
 113                               copy);
 114                         return;
 115                 }
 116                 *p = saved;
 117         }
 118 }
 119
 120 static void close_ns(int ns_fd[LXC_NS_MAX]) {
 121         int i;
 122
 123         for (i = 0; i < LXC_NS_MAX; i++) {
 124                 if (ns_fd[i] > -1) {
 125                         close(ns_fd[i]);
 126                         ns_fd[i] = -1;
 127                 }
 128         }
 129 }
 130
 131 /*
 132  * preserve_ns: open /proc/@pid/ns/@ns for each namespace specified
 133  * in clone_flags.
 134  * Return true on success, false on failure.  On failure, leave an error
 135  * message in *errmsg, which caller must free.
 136  */
 137 static bool preserve_ns(int ns_fd[LXC_NS_MAX], int clone_flags, pid_t pid,
 138                         char **errmsg)
 139 {
 140         int i, ret;
 141         char path[MAXPATHLEN];
 142
 143         for (i = 0; i < LXC_NS_MAX; i++)
 144                 ns_fd[i] = -1;
 145
 146         snprintf(path, MAXPATHLEN, "/proc/%d/ns", pid);
 147         if (access(path, X_OK)) {
 148                 if (asprintf(errmsg, "Kernel does not support setns.") == -1)
 149                         *errmsg = NULL;
 150                 return false;
 151         }
 152
 153         for (i = 0; i < LXC_NS_MAX; i++) {
 154                 if ((clone_flags & ns_info[i].clone_flag) == 0)
 155                         continue;
 156                 snprintf(path, MAXPATHLEN, "/proc/%d/ns/%s", pid,
 157                          ns_info[i].proc_name);
 158                 ns_fd[i] = open(path, O_RDONLY | O_CLOEXEC);
 159                 if (ns_fd[i] < 0)
 160                         goto error;
 161         }
 162
 163         return true;
 164
 165 error:
 166         if (errno == ENOENT) {
 167                 ret = asprintf(errmsg, "Kernel does not support setns for %s",
 168                         ns_info[i].proc_name);
 169         } else {
 170                 ret = asprintf(errmsg, "Failed to open %s: %s",
 171                         path, strerror(errno));
 172         }
 173         if (ret == -1)
 174                 *errmsg = NULL;
 175         close_ns(ns_fd);
 176         return false;
 177 }
 178
 179 static int attach_ns(const int ns_fd[LXC_NS_MAX]) {
 180         int i;
 181
 182         for (i = 0; i < LXC_NS_MAX; i++) {
 183                 if (ns_fd[i] < 0)
 184                         continue;
 185
 186                 if (setns(ns_fd[i], 0) != 0)
 187                         goto error;
 188         }
 189         return 0;
 190
 191 error:
 192         SYSERROR("failed to set namespace '%s'", ns_info[i].proc_name);
 193         return -1;
 194 }
 195
 196 static int match_fd(int fd)
 197 {
 198         return (fd == 0 || fd == 1 || fd == 2);
 199 }
 200
 201 /*
 202  * Check for any fds we need to close
 203  * * if fd_to_ignore != -1, then if we find that fd open we will ignore it.
 204  * * By default we warn about open fds we find.
 205  * * If closeall is true, we will close open fds.
 206  * * If lxc-start was passed "-C", then conf->close_all_fds will be true,
 207  *     in which case we also close all open fds.
 208  * * A daemonized container will always pass closeall=true.
 209  */
 210 int lxc_check_inherited(struct lxc_conf *conf, bool closeall, int fd_to_ignore)
 211 {
 212         struct dirent dirent, *direntp;
 213         int fd, fddir;
 214         DIR *dir;
 215
 216         if (conf && conf->close_all_fds)
 217                 closeall = true;
 218
 219 restart:
 220         dir = opendir("/proc/self/fd");
 221         if (!dir) {
 222                 WARN("failed to open directory: %m");
 223                 return -1;
 224         }
 225
 226         fddir = dirfd(dir);
 227
 228         while (!readdir_r(dir, &dirent, &direntp)) {
 229                 if (!direntp)
 230                         break;
 231
 232                 if (!strcmp(direntp->d_name, "."))
 233                         continue;
 234
 235                 if (!strcmp(direntp->d_name, ".."))
 236                         continue;
 237
 238                 fd = atoi(direntp->d_name);
 239
 240                 if (fd == fddir || fd == lxc_log_fd || fd == fd_to_ignore)
 241                         continue;
 242
 243                 if (current_config && fd == current_config->logfd)
 244                         continue;
 245
 246                 if (match_fd(fd))
 247                         continue;
 248
 249                 if (closeall) {
 250                         close(fd);
 251                         closedir(dir);
 252                         INFO("closed inherited fd %d", fd);
 253                         goto restart;
 254                 }
 255                 WARN("inherited fd %d", fd);
 256         }
 257
 258         closedir(dir); /* cannot fail */
 259         return 0;
 260 }
 261
 262 static int setup_signal_fd(sigset_t *oldmask)
 263 {
 264         sigset_t mask;
 265         int fd;
 266
 267         /* Block everything except serious error signals */
 268         if (sigfillset(&mask) ||
 269             sigdelset(&mask, SIGILL) ||
 270             sigdelset(&mask, SIGSEGV) ||
 271             sigdelset(&mask, SIGBUS) ||
 272             sigdelset(&mask, SIGWINCH) ||
 273             sigprocmask(SIG_BLOCK, &mask, oldmask)) {
 274                 SYSERROR("failed to set signal mask");
 275                 return -1;
 276         }
 277
 278         fd = signalfd(-1, &mask, 0);
 279         if (fd < 0) {
 280                 SYSERROR("failed to create the signal fd");
 281                 return -1;
 282         }
 283
 284         if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {
 285                 SYSERROR("failed to set sigfd to close-on-exec");
 286                 close(fd);
 287                 return -1;
 288         }
 289
 290         DEBUG("sigchild handler set");
 291
 292         return fd;
 293 }
 294
 295 static int signal_handler(int fd, uint32_t events, void *data,
 296                           struct lxc_epoll_descr *descr)
 297 {
 298         struct signalfd_siginfo siginfo;
 299         siginfo_t info;
 300         int ret;
 301         pid_t *pid = data;
 302         bool init_died = false;
 303
 304         ret = read(fd, &siginfo, sizeof(siginfo));
 305         if (ret < 0) {
 306                 ERROR("failed to read signal info");
 307                 return -1;
 308         }
 309
 310         if (ret != sizeof(siginfo)) {
 311                 ERROR("unexpected siginfo size");
 312                 return -1;
 313         }
 314
 315         // check whether init is running
 316         info.si_pid = 0;
 317         ret = waitid(P_PID, *pid, &info, WEXITED | WNOWAIT | WNOHANG);
 318         if (ret == 0 && info.si_pid == *pid) {
 319                 init_died = true;
 320         }
 321
 322         if (siginfo.ssi_signo != SIGCHLD) {
 323                 kill(*pid, siginfo.ssi_signo);
 324                 INFO("forwarded signal %d to pid %d", siginfo.ssi_signo, *pid);
 325                 return init_died ? 1 : 0;
 326         }
 327
 328         if (siginfo.ssi_code == CLD_STOPPED ||
 329             siginfo.ssi_code == CLD_CONTINUED) {
 330                 INFO("container init process was stopped/continued");
 331                 return init_died ? 1 : 0;
 332         }
 333
 334         /* more robustness, protect ourself from a SIGCHLD sent
 335          * by a process different from the container init
 336          */
 337         if (siginfo.ssi_pid != *pid) {
 338                 WARN("invalid pid for SIGCHLD");
 339                 return init_died ? 1 : 0;
 340         }
 341
 342         DEBUG("container init process exited");
 343         return 1;
 344 }
 345
 346 int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
 347 {
 348         handler->state = state;
 349         lxc_monitor_send_state(name, state, handler->lxcpath);
 350         return 0;
 351 }
 352
 353 int lxc_poll(const char *name, struct lxc_handler *handler)
 354 {
 355         int sigfd = handler->sigfd;
 356         int pid = handler->pid;
 357         struct lxc_epoll_descr descr;
 358
 359         if (lxc_mainloop_open(&descr)) {
 360                 ERROR("failed to create mainloop");
 361                 goto out_sigfd;
 362         }
 363
 364         if (lxc_mainloop_add_handler(&descr, sigfd, signal_handler, &pid)) {
 365                 ERROR("failed to add handler for the signal");
 366                 goto out_mainloop_open;
 367         }
 368
 369         if (lxc_console_mainloop_add(&descr, handler->conf)) {
 370                 ERROR("failed to add console handler to mainloop");
 371                 goto out_mainloop_open;
 372         }
 373
 374         if (lxc_cmd_mainloop_add(name, &descr, handler)) {
 375                 ERROR("failed to add command handler to mainloop");
 376                 goto out_mainloop_open;
 377         }
 378
 379         if (handler->conf->need_utmp_watch) {
 380                 #if HAVE_SYS_CAPABILITY_H
 381                 if (lxc_utmp_mainloop_add(&descr, handler)) {
 382                         ERROR("failed to add utmp handler to mainloop");
 383                         goto out_mainloop_open;
 384                 }
 385                 #else
 386                         DEBUG("not starting utmp handler as cap_sys_boot cannot be dropped without capabilities support");
 387                 #endif
 388         }
 389
 390         return lxc_mainloop(&descr, -1);
 391
 392 out_mainloop_open:
 393         lxc_mainloop_close(&descr);
 394 out_sigfd:
 395         close(sigfd);
 396         return -1;
 397 }
 398
 399 struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char *lxcpath)
 400 {
 401         int i;
 402         struct lxc_handler *handler;
 403
 404         handler = malloc(sizeof(*handler));
 405         if (!handler)
 406                 return NULL;
 407
 408         memset(handler, 0, sizeof(*handler));
 409
 410         handler->ttysock[0] = handler->ttysock[1] = -1;
 411         handler->conf = conf;
 412         handler->lxcpath = lxcpath;
 413         handler->pinfd = -1;
 414
 415         for (i = 0; i < LXC_NS_MAX; i++)
 416                 handler->nsfd[i] = -1;
 417
 418         lsm_init();
 419
 420         handler->name = strdup(name);
 421         if (!handler->name) {
 422                 ERROR("failed to allocate memory");
 423                 goto out_free;
 424         }
 425
 426         if (lxc_cmd_init(name, handler, lxcpath))
 427                 goto out_free_name;
 428
 429         if (lxc_read_seccomp_config(conf) != 0) {
 430                 ERROR("failed loading seccomp policy");
 431                 goto out_close_maincmd_fd;
 432         }
 433
 434         /* Begin by setting the state to STARTING */
 435         if (lxc_set_state(name, handler, STARTING)) {
 436                 ERROR("failed to set state '%s'", lxc_state2str(STARTING));
 437                 goto out_close_maincmd_fd;
 438         }
 439
 440         /* Start of environment variable setup for hooks */
 441         if (name && setenv("LXC_NAME", name, 1)) {
 442                 SYSERROR("failed to set environment variable for container name");
 443         }
 444         if (conf->rcfile && setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
 445                 SYSERROR("failed to set environment variable for config path");
 446         }
 447         if (conf->rootfs.mount && setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
 448                 SYSERROR("failed to set environment variable for rootfs mount");
 449         }
 450         if (conf->rootfs.path && setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
 451                 SYSERROR("failed to set environment variable for rootfs mount");
 452         }
 453         if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
 454                 SYSERROR("failed to set environment variable for console path");
 455         }
 456         if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
 457                 SYSERROR("failed to set environment variable for console log");
 458         }
 459         if (setenv("LXC_CGNS_AWARE", "1", 1)) {
 460                 SYSERROR("failed to set LXC_CGNS_AWARE environment variable");
 461         }
 462         /* End of environment variable setup for hooks */
 463
 464         if (run_lxc_hooks(name, "pre-start", conf, handler->lxcpath, NULL)) {
 465                 ERROR("failed to run pre-start hooks for container '%s'.", name);
 466                 goto out_aborting;
 467         }
 468
 469         /* the signal fd has to be created before forking otherwise
 470          * if the child process exits before we setup the signal fd,
 471          * the event will be lost and the command will be stuck */
 472         handler->sigfd = setup_signal_fd(&handler->oldmask);
 473         if (handler->sigfd < 0) {
 474                 ERROR("failed to set sigchild fd handler");
 475                 goto out_delete_tty;
 476         }
 477
 478         /* do this after setting up signals since it might unblock SIGWINCH */
 479         if (lxc_console_create(conf)) {
 480                 ERROR("failed to create console");
 481                 goto out_restore_sigmask;
 482         }
 483
 484         if (ttys_shift_ids(conf) < 0) {
 485                 ERROR("Failed to shift tty into container");
 486                 goto out_restore_sigmask;
 487         }
 488
 489         INFO("'%s' is initialized", name);
 490         return handler;
 491
 492 out_restore_sigmask:
 493         sigprocmask(SIG_SETMASK, &handler->oldmask, NULL);
 494 out_delete_tty:
 495         lxc_delete_tty(&conf->tty_info);
 496 out_aborting:
 497         lxc_set_state(name, handler, ABORTING);
 498 out_close_maincmd_fd:
 499         close(conf->maincmd_fd);
 500         conf->maincmd_fd = -1;
 501 out_free_name:
 502         free(handler->name);
 503         handler->name = NULL;
 504 out_free:
 505         free(handler);
 506         return NULL;
 507 }
 508
 509 void lxc_fini(const char *name, struct lxc_handler *handler)
 510 {
 511         int i, rc;
 512         pid_t self = getpid();
 513         char *namespaces[LXC_NS_MAX+1];
 514         size_t namespace_count = 0;
 515
 516         /* The STOPPING state is there for future cleanup code
 517          * which can take awhile
 518          */
 519         lxc_set_state(name, handler, STOPPING);
 520
 521         for (i = 0; i < LXC_NS_MAX; i++) {
 522                 if (handler->nsfd[i] != -1) {
 523                         rc = asprintf(&namespaces[namespace_count], "%s:/proc/%d/fd/%d",
 524                                       ns_info[i].proc_name, self, handler->nsfd[i]);
 525                         if (rc == -1) {
 526                                 SYSERROR("failed to allocate memory");
 527                                 break;
 528                         }
 529                         ++namespace_count;
 530                 }
 531         }
 532         namespaces[namespace_count] = NULL;
 533
 534         if (handler->conf->reboot && setenv("LXC_TARGET", "reboot", 1)) {
 535                 SYSERROR("failed to set environment variable for stop target");
 536         }
 537         if (!handler->conf->reboot && setenv("LXC_TARGET", "stop", 1)) {
 538                 SYSERROR("failed to set environment variable for stop target");
 539         }
 540
 541         if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath, namespaces))
 542                 ERROR("failed to run stop hooks for container '%s'.", name);
 543
 544         while (namespace_count--)
 545                 free(namespaces[namespace_count]);
 546         for (i = 0; i < LXC_NS_MAX; i++) {
 547                 if (handler->nsfd[i] != -1) {
 548                         close(handler->nsfd[i]);
 549                         handler->nsfd[i] = -1;
 550                 }
 551         }
 552         lxc_set_state(name, handler, STOPPED);
 553
 554         if (run_lxc_hooks(name, "post-stop", handler->conf, handler->lxcpath, NULL)) {
 555                 ERROR("failed to run post-stop hooks for container '%s'.", name);
 556                 if (handler->conf->reboot) {
 557                         WARN("Container will be stopped instead of rebooted.");
 558                         handler->conf->reboot = 0;
 559                         setenv("LXC_TARGET", "stop", 1);
 560                 }
 561         }
 562
 563         /* reset mask set by setup_signal_fd */
 564         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
 565                 WARN("failed to restore sigprocmask");
 566
 567         lxc_console_delete(&handler->conf->console);
 568         lxc_delete_tty(&handler->conf->tty_info);
 569         close(handler->conf->maincmd_fd);
 570         handler->conf->maincmd_fd = -1;
 571         free(handler->name);
 572         if (handler->ttysock[0] != -1) {
 573                 close(handler->ttysock[0]);
 574                 close(handler->ttysock[1]);
 575         }
 576
 577         if (handler->conf->ephemeral == 1 && handler->conf->reboot != 1)
 578                 lxc_destroy_container_on_signal(handler, name);
 579
 580         cgroup_destroy(handler);
 581         free(handler);
 582 }
 583
 584 void lxc_abort(const char *name, struct lxc_handler *handler)
 585 {
 586         int ret, status;
 587
 588         lxc_set_state(name, handler, ABORTING);
 589         if (handler->pid > 0)
 590                 kill(handler->pid, SIGKILL);
 591         while ((ret = waitpid(-1, &status, 0)) > 0) ;
 592 }
 593
 594 #include <sys/reboot.h>
 595 #include <linux/reboot.h>
 596
 597 /*
 598  * reboot(LINUX_REBOOT_CMD_CAD_ON) will return -EINVAL
 599  * in a child pid namespace if container reboot support exists.
 600  * Otherwise, it will either succeed or return -EPERM.
 601  */
 602 static int container_reboot_supported(void *arg)
 603 {
 604         int *cmd = arg;
 605         int ret;
 606
 607         ret = reboot(*cmd);
 608         if (ret == -1 && errno == EINVAL)
 609                 return 1;
 610         return 0;
 611 }
 612
 613 static int must_drop_cap_sys_boot(struct lxc_conf *conf)
 614 {
 615         FILE *f;
 616         int ret, cmd, v, flags;
 617         long stack_size = 4096;
 618         void *stack = alloca(stack_size);
 619         int status;
 620         pid_t pid;
 621
 622         f = fopen("/proc/sys/kernel/ctrl-alt-del", "r");
 623         if (!f) {
 624                 DEBUG("failed to open /proc/sys/kernel/ctrl-alt-del");
 625                 return 1;
 626         }
 627
 628         ret = fscanf(f, "%d", &v);
 629         fclose(f);
 630         if (ret != 1) {
 631                 DEBUG("Failed to read /proc/sys/kernel/ctrl-alt-del");
 632                 return 1;
 633         }
 634         cmd = v ? LINUX_REBOOT_CMD_CAD_ON : LINUX_REBOOT_CMD_CAD_OFF;
 635
 636         flags = CLONE_NEWPID | SIGCHLD;
 637         if (!lxc_list_empty(&conf->id_map))
 638                 flags |= CLONE_NEWUSER;
 639
 640 #ifdef __ia64__
 641         pid = __clone2(container_reboot_supported, stack, stack_size, flags,  &cmd);
 642 #else
 643         stack += stack_size;
 644         pid = clone(container_reboot_supported, stack, flags, &cmd);
 645 #endif
 646         if (pid < 0) {
 647                 if (flags & CLONE_NEWUSER)
 648                         ERROR("failed to clone (%#x): %s (includes CLONE_NEWUSER)", flags, strerror(errno));
 649                 else
 650                         ERROR("failed to clone (%#x): %s", flags, strerror(errno));
 651                 return -1;
 652         }
 653         if (wait(&status) < 0) {
 654                 SYSERROR("unexpected wait error: %m");
 655                 return -1;
 656         }
 657
 658         if (WEXITSTATUS(status) != 1)
 659                 return 1;
 660
 661         return 0;
 662 }
 663
 664 /*
 665  * netpipe is used in the unprivileged case to transfer the ifindexes
 666  * from parent to child
 667  */
 668 static int netpipe = -1;
 669
 670 static inline int count_veths(struct lxc_list *network)
 671 {
 672         struct lxc_list *iterator;
 673         struct lxc_netdev *netdev;
 674         int count = 0;
 675
 676         lxc_list_for_each(iterator, network) {
 677                 netdev = iterator->elem;
 678                 if (netdev->type != LXC_NET_VETH)
 679                         continue;
 680                 count++;
 681         }
 682         return count;
 683 }
 684
 685 static int read_unpriv_netifindex(struct lxc_list *network)
 686 {
 687         struct lxc_list *iterator;
 688         struct lxc_netdev *netdev;
 689
 690         if (netpipe == -1)
 691                 return 0;
 692         lxc_list_for_each(iterator, network) {
 693                 netdev = iterator->elem;
 694                 if (netdev->type != LXC_NET_VETH)
 695                         continue;
 696                 if (!(netdev->name = malloc(IFNAMSIZ))) {
 697                         ERROR("Out of memory");
 698                         close(netpipe);
 699                         return -1;
 700                 }
 701                 if (read(netpipe, netdev->name, IFNAMSIZ) != IFNAMSIZ) {
 702                         close(netpipe);
 703                         return -1;
 704                 }
 705         }
 706         close(netpipe);
 707         return 0;
 708 }
 709
 710 static int do_start(void *data)
 711 {
 712         struct lxc_list *iterator;
 713         struct lxc_handler *handler = data;
 714         int devnull_fd = -1, ret;
 715         char path[PATH_MAX];
 716
 717         if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL)) {
 718                 SYSERROR("failed to set sigprocmask");
 719                 return -1;
 720         }
 721
 722         /* This prctl must be before the synchro, so if the parent
 723          * dies before we set the parent death signal, we will detect
 724          * its death with the synchro right after, otherwise we have
 725          * a window where the parent can exit before we set the pdeath
 726          * signal leading to a unsupervized container.
 727          */
 728         if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0)) {
 729                 SYSERROR("failed to set pdeath signal");
 730                 return -1;
 731         }
 732
 733         lxc_sync_fini_parent(handler);
 734
 735         /* don't leak the pinfd to the container */
 736         if (handler->pinfd >= 0) {
 737                 close(handler->pinfd);
 738         }
 739
 740         if (lxc_sync_wait_parent(handler, LXC_SYNC_STARTUP))
 741                 return -1;
 742
 743         /* Unshare CLONE_NEWNET after CLONE_NEWUSER  - see
 744           https://github.com/lxc/lxd/issues/1978 */
 745         if ((handler->clone_flags & (CLONE_NEWNET | CLONE_NEWUSER)) ==
 746                         (CLONE_NEWNET | CLONE_NEWUSER)) {
 747                 ret = unshare(CLONE_NEWNET);
 748                 if (ret < 0) {
 749                         SYSERROR("Error unsharing network namespace");
 750                         goto out_warn_father;
 751                 }
 752         }
 753
 754         /* Tell the parent task it can begin to configure the
 755          * container and wait for it to finish
 756          */
 757         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
 758                 return -1;
 759
 760         if (read_unpriv_netifindex(&handler->conf->network) < 0)
 761                 goto out_warn_father;
 762
 763         /*
 764          * if we are in a new user namespace, become root there to have
 765          * privilege over our namespace. When using lxc-execute we default to root,
 766          * but this can be overriden using the lxc.init_uid and lxc.init_gid
 767          * configuration options.
 768          */
 769         if (!lxc_list_empty(&handler->conf->id_map)) {
 770                 gid_t new_gid = 0;
 771                 if (handler->conf->is_execute && handler->conf->init_gid)
 772                         new_gid = handler->conf->init_gid;
 773
 774                 uid_t new_uid = 0;
 775                 if (handler->conf->is_execute && handler->conf->init_uid)
 776                         new_uid = handler->conf->init_uid;
 777
 778                 NOTICE("switching to gid/uid %d/%d in new user namespace", new_gid, new_uid);
 779                 if (setgid(new_gid)) {
 780                         SYSERROR("setgid");
 781                         goto out_warn_father;
 782                 }
 783                 if (setuid(new_uid)) {
 784                         SYSERROR("setuid");
 785                         goto out_warn_father;
 786                 }
 787                 if (setgroups(0, NULL)) {
 788                         SYSERROR("setgroups");
 789                         goto out_warn_father;
 790                 }
 791         }
 792
 793         if (access(handler->lxcpath, X_OK)) {
 794                 print_top_failing_dir(handler->lxcpath);
 795                 goto out_warn_father;
 796         }
 797
 798         #if HAVE_SYS_CAPABILITY_H
 799         if (handler->conf->need_utmp_watch) {
 800                 if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
 801                         SYSERROR("failed to remove CAP_SYS_BOOT capability");
 802                         goto out_warn_father;
 803                 }
 804                 DEBUG("Dropped cap_sys_boot");
 805         }
 806         #endif
 807
 808         ret = snprintf(path, sizeof(path), "%s/dev/null", handler->conf->rootfs.mount);
 809         if (ret < 0 || ret >= sizeof(path)) {
 810                 SYSERROR("sprintf'd too many chars");
 811                 goto out_warn_father;
 812         }
 813
 814         /* In order to checkpoint restore, we need to have everything in the
 815          * same mount namespace. However, some containers may not have a
 816          * reasonable /dev (in particular, they may not have /dev/null), so we
 817          * can't set init's std fds to /dev/null by opening it from inside the
 818          * container.
 819          *
 820          * If that's the case, fall back to using the host's /dev/null. This
 821          * means that migration won't work, but at least we won't spew output
 822          * where it isn't wanted.
 823          */
 824         if (handler->backgrounded && !handler->conf->autodev && access(path, F_OK) < 0) {
 825                 devnull_fd = open_devnull();
 826
 827                 if (devnull_fd < 0)
 828                         goto out_warn_father;
 829                 WARN("using host's /dev/null for container init's std fds, migraiton won't work");
 830         }
 831
 832         /* Setup the container, ip, names, utsname, ... */
 833         if (lxc_setup(handler)) {
 834                 ERROR("failed to setup the container");
 835                 goto out_warn_father;
 836         }
 837
 838         /* ask father to setup cgroups and wait for him to finish */
 839         if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
 840                 goto out_error;
 841
 842         /* Set the label to change to when we exec(2) the container's init */
 843         if (lsm_process_label_set(NULL, handler->conf, 1, 1) < 0)
 844                 goto out_warn_father;
 845
 846         /* Some init's such as busybox will set sane tty settings on stdin,
 847          * stdout, stderr which it thinks is the console. We already set them
 848          * the way we wanted on the real terminal, and we want init to do its
 849          * setup on its console ie. the pty allocated in lxc_console_create()
 850          * so make sure that that pty is stdin,stdout,stderr.
 851          */
 852         if (lxc_console_set_stdfds(handler->conf->console.slave) < 0)
 853                 goto out_warn_father;
 854
 855         /* If we mounted a temporary proc, then unmount it now */
 856         tmp_proc_unmount(handler->conf);
 857
 858         if (lxc_seccomp_load(handler->conf) != 0)
 859                 goto out_warn_father;
 860
 861         if (run_lxc_hooks(handler->name, "start", handler->conf, handler->lxcpath, NULL)) {
 862                 ERROR("failed to run start hooks for container '%s'.", handler->name);
 863                 goto out_warn_father;
 864         }
 865
 866         /* The clearenv() and putenv() calls have been moved here
 867          * to allow us to use environment variables passed to the various
 868          * hooks, such as the start hook above.  Not all of the
 869          * variables like CONFIG_PATH or ROOTFS are valid in this
 870          * context but others are. */
 871         if (clearenv()) {
 872                 SYSERROR("failed to clear environment");
 873                 /* don't error out though */
 874         }
 875
 876         lxc_list_for_each(iterator, &handler->conf->environment) {
 877                 if (putenv((char *)iterator->elem)) {
 878                         SYSERROR("failed to set environment variable '%s'", (char *)iterator->elem);
 879                         goto out_warn_father;
 880                 }
 881         }
 882
 883         if (putenv("container=lxc")) {
 884                 SYSERROR("failed to set environment variable 'container=lxc'");
 885                 goto out_warn_father;
 886         }
 887
 888         if (handler->conf->pty_names) {
 889                 if (putenv(handler->conf->pty_names)) {
 890                         SYSERROR("failed to set environment variable for container ptys");
 891                         goto out_warn_father;
 892                 }
 893         }
 894
 895         close(handler->sigfd);
 896
 897         if (devnull_fd < 0) {
 898                 devnull_fd = open_devnull();
 899
 900                 if (devnull_fd < 0)
 901                         goto out_warn_father;
 902         }
 903
 904         if (handler->backgrounded && set_stdfds(devnull_fd))
 905                 goto out_warn_father;
 906
 907         if (devnull_fd >= 0) {
 908                 close(devnull_fd);
 909                 devnull_fd = -1;
 910         }
 911
 912         if (cgns_supported() && unshare(CLONE_NEWCGROUP) != 0) {
 913                 SYSERROR("Failed to unshare cgroup namespace");
 914                 goto out_warn_father;
 915         }
 916
 917         setsid();
 918
 919         /* after this call, we are in error because this
 920          * ops should not return as it execs */
 921         handler->ops->start(handler, handler->data);
 922
 923 out_warn_father:
 924         /* we want the parent to know something went wrong, so we return a special
 925          * error code. */
 926         lxc_sync_wake_parent(handler, LXC_SYNC_ERROR);
 927
 928 out_error:
 929         if (devnull_fd >= 0)
 930                 close(devnull_fd);
 931
 932         return -1;
 933 }
 934
 935 static int save_phys_nics(struct lxc_conf *conf)
 936 {
 937         struct lxc_list *iterator;
 938         int am_root = (getuid() == 0);
 939
 940         if (!am_root)
 941                 return 0;
 942
 943         lxc_list_for_each(iterator, &conf->network) {
 944                 struct lxc_netdev *netdev = iterator->elem;
 945
 946                 if (netdev->type != LXC_NET_PHYS)
 947                         continue;
 948                 conf->saved_nics = realloc(conf->saved_nics,
 949                                 (conf->num_savednics+1)*sizeof(struct saved_nic));
 950                 if (!conf->saved_nics) {
 951                         SYSERROR("failed to allocate memory");
 952                         return -1;
 953                 }
 954                 conf->saved_nics[conf->num_savednics].ifindex = netdev->ifindex;
 955                 conf->saved_nics[conf->num_savednics].orig_name = strdup(netdev->link);
 956                 if (!conf->saved_nics[conf->num_savednics].orig_name) {
 957                         SYSERROR("failed to allocate memory");
 958                         return -1;
 959                 }
 960                 INFO("stored saved_nic #%d idx %d name %s", conf->num_savednics,
 961                         conf->saved_nics[conf->num_savednics].ifindex,
 962                         conf->saved_nics[conf->num_savednics].orig_name);
 963                 conf->num_savednics++;
 964         }
 965
 966         return 0;
 967 }
 968
 969 static int recv_fd(int sock, int *fd)
 970 {
 971         if (lxc_abstract_unix_recv_fd(sock, fd, NULL, 0) < 0) {
 972                 SYSERROR("Error receiving tty fd from child");
 973                 return -1;
 974         }
 975         if (*fd == -1)
 976                 return -1;
 977         return 0;
 978 }
 979
 980 static int recv_ttys_from_child(struct lxc_handler *handler)
 981 {
 982         struct lxc_conf *conf = handler->conf;
 983         int i, sock = handler->ttysock[1];
 984         struct lxc_tty_info *tty_info = &conf->tty_info;
 985
 986         if (!conf->tty)
 987                 return 0;
 988
 989         tty_info->pty_info = malloc(sizeof(*tty_info->pty_info)*conf->tty);
 990         if (!tty_info->pty_info) {
 991                 SYSERROR("failed to allocate pty_info");
 992                 return -1;
 993         }
 994
 995         for (i = 0; i < conf->tty; i++) {
 996                 struct lxc_pty_info *pty_info = &tty_info->pty_info[i];
 997                 pty_info->busy = 0;
 998                 if (recv_fd(sock, &pty_info->slave) < 0 ||
 999                                 recv_fd(sock, &pty_info->master) < 0) {
1000                         ERROR("Error receiving tty info from child");
1001                         return -1;
1002                 }
1003         }
1004         tty_info->nbtty = conf->tty;
1005
1006         return 0;
1007 }
1008
1009 void resolve_clone_flags(struct lxc_handler *handler)
1010 {
1011         handler->clone_flags = CLONE_NEWPID | CLONE_NEWNS;
1012
1013         if (!lxc_list_empty(&handler->conf->id_map)) {
1014                 INFO("Cloning a new user namespace");
1015                 handler->clone_flags |= CLONE_NEWUSER;
1016         }
1017
1018         if (handler->conf->inherit_ns_fd[LXC_NS_NET] == -1) {
1019                 if (!lxc_requests_empty_network(handler))
1020                         handler->clone_flags |= CLONE_NEWNET;
1021         } else {
1022                 INFO("Inheriting a net namespace");
1023         }
1024
1025         if (handler->conf->inherit_ns_fd[LXC_NS_IPC] == -1) {
1026                 handler->clone_flags |= CLONE_NEWIPC;
1027         } else {
1028                 INFO("Inheriting an IPC namespace");
1029         }
1030
1031         if (handler->conf->inherit_ns_fd[LXC_NS_UTS] == -1) {
1032                 handler->clone_flags |= CLONE_NEWUTS;
1033         } else {
1034                 INFO("Inheriting a UTS namespace");
1035         }
1036 }
1037
1038 static int lxc_spawn(struct lxc_handler *handler)
1039 {
1040         int failed_before_rename = 0;
1041         const char *name = handler->name;
1042         char *errmsg = NULL;
1043         bool cgroups_connected = false;
1044         int saved_ns_fd[LXC_NS_MAX];
1045         int preserve_mask = 0, i, flags;
1046         int netpipepair[2], nveths;
1047
1048         netpipe = -1;
1049
1050         for (i = 0; i < LXC_NS_MAX; i++)
1051                 if (handler->conf->inherit_ns_fd[i] != -1)
1052                         preserve_mask |= ns_info[i].clone_flag;
1053
1054         if (lxc_sync_init(handler))
1055                 return -1;
1056
1057         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, handler->ttysock) < 0) {
1058                 lxc_sync_fini(handler);
1059                 return -1;
1060         }
1061
1062         resolve_clone_flags(handler);
1063
1064         if (handler->clone_flags & CLONE_NEWNET) {
1065                 if (!lxc_list_empty(&handler->conf->network)) {
1066
1067                         /* Find gateway addresses from the link device, which is
1068                          * no longer accessible inside the container. Do this
1069                          * before creating network interfaces, since goto
1070                          * out_delete_net does not work before lxc_clone. */
1071                         if (lxc_find_gateway_addresses(handler)) {
1072                                 ERROR("failed to find gateway addresses");
1073                                 lxc_sync_fini(handler);
1074                                 return -1;
1075                         }
1076
1077                         /* that should be done before the clone because we will
1078                          * fill the netdev index and use them in the child
1079                          */
1080                         if (lxc_create_network(handler)) {
1081                                 ERROR("failed to create the network");
1082                                 lxc_sync_fini(handler);
1083                                 return -1;
1084                         }
1085                 }
1086
1087                 if (save_phys_nics(handler->conf)) {
1088                         ERROR("failed to save physical nic info");
1089                         goto out_abort;
1090                 }
1091         }
1092
1093         if (!cgroup_init(handler)) {
1094                 ERROR("failed initializing cgroup support");
1095                 goto out_delete_net;
1096         }
1097
1098         cgroups_connected = true;
1099
1100         if (!cgroup_create(handler)) {
1101                 ERROR("failed creating cgroups");
1102                 goto out_delete_net;
1103         }
1104
1105         /*
1106          * if the rootfs is not a blockdev, prevent the container from
1107          * marking it readonly.
1108          *
1109          * if the container is unprivileged then skip rootfs pinning
1110          */
1111         if (lxc_list_empty(&handler->conf->id_map)) {
1112                 handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
1113                 if (handler->pinfd == -1)
1114                         INFO("failed to pin the container's rootfs");
1115         }
1116
1117         if (!preserve_ns(saved_ns_fd, preserve_mask, getpid(), &errmsg)) {
1118                 SYSERROR("Failed to preserve requested namespaces: %s",
1119                         errmsg ? errmsg : "(Out of memory)");
1120                 free(errmsg);
1121                 goto out_delete_net;
1122         }
1123         if (attach_ns(handler->conf->inherit_ns_fd) < 0)
1124                 goto out_delete_net;
1125
1126         if (am_unpriv() && (nveths = count_veths(&handler->conf->network))) {
1127                 if (pipe(netpipepair) < 0) {
1128                         SYSERROR("Error creating pipe");
1129                         goto out_delete_net;
1130                 }
1131                 /* store netpipe in the global var for do_start's use */
1132                 netpipe = netpipepair[0];
1133         }
1134
1135         /* Create a process in a new set of namespaces */
1136         flags = handler->clone_flags;
1137         if (handler->clone_flags & CLONE_NEWUSER)
1138                 flags &= ~CLONE_NEWNET;
1139         handler->pid = lxc_clone(do_start, handler, handler->clone_flags);
1140         if (handler->pid < 0) {
1141                 SYSERROR("failed to fork into a new namespace");
1142                 goto out_delete_net;
1143         }
1144
1145         if (!preserve_ns(handler->nsfd, handler->clone_flags | preserve_mask, handler->pid, &errmsg)) {
1146                 INFO("Failed to store namespace references for stop hook: %s",
1147                         errmsg ? errmsg : "(Out of memory)");
1148                 free(errmsg);
1149         }
1150
1151         if (attach_ns(saved_ns_fd))
1152                 WARN("failed to restore saved namespaces");
1153
1154         lxc_sync_fini_child(handler);
1155
1156         /* map the container uids - the container became an invalid
1157          * userid the moment it was cloned with CLONE_NEWUSER - this
1158          * call doesn't change anything immediately, but allows the
1159          * container to setuid(0) (0 being mapped to something else on
1160          * the host) later to become a valid uid again */
1161         if (lxc_map_ids(&handler->conf->id_map, handler->pid)) {
1162                 ERROR("failed to set up id mapping");
1163                 goto out_delete_net;
1164         }
1165
1166         if (lxc_sync_wake_child(handler, LXC_SYNC_STARTUP)) {
1167                 failed_before_rename = 1;
1168                 goto out_delete_net;
1169         }
1170
1171         if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE)) {
1172                 failed_before_rename = 1;
1173                 goto out_delete_net;
1174         }
1175
1176         if (!cgroup_create_legacy(handler)) {
1177                 ERROR("failed to setup the legacy cgroups for %s", name);
1178                 goto out_delete_net;
1179         }
1180         if (!cgroup_setup_limits(handler, false)) {
1181                 ERROR("failed to setup the cgroup limits for '%s'", name);
1182                 goto out_delete_net;
1183         }
1184
1185         if (!cgroup_enter(handler))
1186                 goto out_delete_net;
1187
1188         if (!cgroup_chown(handler))
1189                 goto out_delete_net;
1190
1191         if (failed_before_rename)
1192                 goto out_delete_net;
1193
1194         /* Create the network configuration */
1195         if (handler->clone_flags & CLONE_NEWNET) {
1196                 if (lxc_assign_network(handler->lxcpath, handler->name,
1197                                         &handler->conf->network, handler->pid)) {
1198                         ERROR("failed to create the configured network");
1199                         goto out_delete_net;
1200                 }
1201         }
1202
1203         if (netpipe != -1) {
1204                 struct lxc_list *iterator;
1205                 struct lxc_netdev *netdev;
1206
1207                 close(netpipe);
1208                 lxc_list_for_each(iterator, &handler->conf->network) {
1209                         netdev = iterator->elem;
1210                         if (netdev->type != LXC_NET_VETH)
1211                                 continue;
1212                         if (write(netpipepair[1], netdev->name, IFNAMSIZ) != IFNAMSIZ) {
1213                                 ERROR("Error writing veth name to container");
1214                                 goto out_delete_net;
1215                         }
1216                 }
1217                 close(netpipepair[1]);
1218         }
1219
1220         /* Tell the child to continue its initialization.  we'll get
1221          * LXC_SYNC_CGROUP when it is ready for us to setup cgroups
1222          */
1223         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
1224                 goto out_delete_net;
1225
1226         if (!cgroup_setup_limits(handler, true)) {
1227                 ERROR("failed to setup the devices cgroup for '%s'", name);
1228                 goto out_delete_net;
1229         }
1230
1231         cgroup_disconnect();
1232         cgroups_connected = false;
1233
1234         /* read tty fds allocated by child */
1235         if (recv_ttys_from_child(handler) < 0) {
1236                 ERROR("failed to receive tty info from child");
1237                 goto out_delete_net;
1238         }
1239
1240         /* Tell the child to complete its initialization and wait for
1241          * it to exec or return an error.  (the child will never
1242          * return LXC_SYNC_POST_CGROUP+1.  It will either close the
1243          * sync pipe, causing lxc_sync_barrier_child to return
1244          * success, or return a different value, causing us to error
1245          * out).
1246          */
1247         if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
1248                 return -1;
1249
1250         if (detect_shared_rootfs())
1251                 umount2(handler->conf->rootfs.mount, MNT_DETACH);
1252
1253         if (handler->ops->post_start(handler, handler->data))
1254                 goto out_abort;
1255
1256         if (lxc_set_state(name, handler, RUNNING)) {
1257                 ERROR("failed to set state to %s",
1258                               lxc_state2str(RUNNING));
1259                 goto out_abort;
1260         }
1261
1262         lxc_sync_fini(handler);
1263
1264         return 0;
1265
1266 out_delete_net:
1267         if (cgroups_connected)
1268                 cgroup_disconnect();
1269         if (handler->clone_flags & CLONE_NEWNET)
1270                 lxc_delete_network(handler);
1271 out_abort:
1272         lxc_abort(name, handler);
1273         lxc_sync_fini(handler);
1274         if (handler->pinfd >= 0) {
1275                 close(handler->pinfd);
1276                 handler->pinfd = -1;
1277         }
1278
1279         return -1;
1280 }
1281
1282 int get_netns_fd(int pid)
1283 {
1284         char path[MAXPATHLEN];
1285         int ret, fd;
1286
1287         ret = snprintf(path, MAXPATHLEN, "/proc/%d/ns/net", pid);
1288         if (ret < 0 || ret >= MAXPATHLEN) {
1289                 WARN("Failed to pin netns file for pid %d", pid);
1290                 return -1;
1291         }
1292
1293         fd = open(path, O_RDONLY);
1294         if (fd < 0) {
1295                 WARN("Failed to pin netns file %s for pid %d: %s",
1296                                 path, pid, strerror(errno));
1297                 return -1;
1298         }
1299         return fd;
1300 }
1301
1302 int __lxc_start(const char *name, struct lxc_conf *conf,
1303                 struct lxc_operations* ops, void *data, const char *lxcpath,
1304                 bool backgrounded)
1305 {
1306         struct lxc_handler *handler;
1307         int err = -1;
1308         int status;
1309         int netnsfd = -1;
1310
1311         handler = lxc_init(name, conf, lxcpath);
1312         if (!handler) {
1313                 ERROR("failed to initialize the container");
1314                 return -1;
1315         }
1316         handler->ops = ops;
1317         handler->data = data;
1318         handler->backgrounded = backgrounded;
1319
1320         if (must_drop_cap_sys_boot(handler->conf)) {
1321                 #if HAVE_SYS_CAPABILITY_H
1322                 DEBUG("Dropping cap_sys_boot");
1323                 #else
1324                 DEBUG("Can't drop cap_sys_boot as capabilities aren't supported");
1325                 #endif
1326         } else {
1327                 DEBUG("Not dropping cap_sys_boot or watching utmp");
1328                 handler->conf->need_utmp_watch = 0;
1329         }
1330
1331         if (!attach_block_device(handler->conf)) {
1332                 ERROR("Failure attaching block device");
1333                 goto out_fini_nonet;
1334         }
1335
1336         if (geteuid() == 0 && !lxc_list_empty(&conf->id_map)) {
1337                 /* if the backing store is a device, mount it here and now */
1338                 if (rootfs_is_blockdev(conf)) {
1339                         if (unshare(CLONE_NEWNS) < 0) {
1340                                 ERROR("Error unsharing mounts");
1341                                 goto out_fini_nonet;
1342                         }
1343                         remount_all_slave();
1344                         if (do_rootfs_setup(conf, name, lxcpath) < 0) {
1345                                 ERROR("Error setting up rootfs mount as root before spawn");
1346                                 goto out_fini_nonet;
1347                         }
1348                         INFO("Set up container rootfs as host root");
1349                 }
1350         }
1351
1352         err = lxc_spawn(handler);
1353         if (err) {
1354                 ERROR("failed to spawn '%s'", name);
1355                 goto out_detach_blockdev;
1356         }
1357
1358         handler->conf->reboot = 0;
1359
1360         netnsfd = get_netns_fd(handler->pid);
1361
1362         err = lxc_poll(name, handler);
1363         if (err) {
1364                 ERROR("mainloop exited with an error");
1365                 if (netnsfd >= 0)
1366                         close(netnsfd);
1367                 goto out_abort;
1368         }
1369
1370         while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
1371                 continue;
1372
1373         /*
1374          * If the child process exited but was not signaled,
1375          * it didn't call reboot.  This should mean it was an
1376          * lxc-execute which simply exited.  In any case, treat
1377          * it as a 'halt'
1378          */
1379         if (WIFSIGNALED(status)) {
1380                 switch(WTERMSIG(status)) {
1381                 case SIGINT: /* halt */
1382                         DEBUG("Container halting");
1383                         break;
1384                 case SIGHUP: /* reboot */
1385                         DEBUG("Container rebooting");
1386                         handler->conf->reboot = 1;
1387                         break;
1388                 case SIGSYS: /* seccomp */
1389                         DEBUG("Container violated its seccomp policy");
1390                         break;
1391                 default:
1392                         DEBUG("unknown exit status for init: %d", WTERMSIG(status));
1393                         break;
1394                 }
1395         }
1396
1397         DEBUG("Pushing physical nics back to host namespace");
1398         lxc_rename_phys_nics_on_shutdown(netnsfd, handler->conf);
1399
1400         DEBUG("Tearing down virtual network devices used by container");
1401         lxc_delete_network(handler);
1402
1403         if (netnsfd >= 0)
1404                 close(netnsfd);
1405
1406         if (handler->pinfd >= 0) {
1407                 close(handler->pinfd);
1408                 handler->pinfd = -1;
1409         }
1410
1411         lxc_monitor_send_exit_code(name, status, handler->lxcpath);
1412         err =  lxc_error_set_and_log(handler->pid, status);
1413 out_fini:
1414         lxc_delete_network(handler);
1415
1416 out_detach_blockdev:
1417         detach_block_device(handler->conf);
1418
1419 out_fini_nonet:
1420         lxc_fini(name, handler);
1421         return err;
1422
1423 out_abort:
1424         lxc_abort(name, handler);
1425         goto out_fini;
1426 }
1427
1428 struct start_args {
1429         char *const *argv;
1430 };
1431
1432 static int start(struct lxc_handler *handler, void* data)
1433 {
1434         struct start_args *arg = data;
1435
1436         NOTICE("exec'ing '%s'", arg->argv[0]);
1437
1438         execvp(arg->argv[0], arg->argv);
1439         SYSERROR("failed to exec %s", arg->argv[0]);
1440         return 0;
1441 }
1442
1443 static int post_start(struct lxc_handler *handler, void* data)
1444 {
1445         struct start_args *arg = data;
1446
1447         NOTICE("'%s' started with pid '%d'", arg->argv[0], handler->pid);
1448         return 0;
1449 }
1450
1451 static struct lxc_operations start_ops = {
1452         .start = start,
1453         .post_start = post_start
1454 };
1455
1456 int lxc_start(const char *name, char *const argv[], struct lxc_conf *conf,
1457               const char *lxcpath, bool backgrounded)
1458 {
1459         struct start_args start_arg = {
1460                 .argv = argv,
1461         };
1462
1463         conf->need_utmp_watch = 1;
1464         return __lxc_start(name, conf, &start_ops, &start_arg, lxcpath, backgrounded);
1465 }
1466
1467 static void lxc_destroy_container_on_signal(struct lxc_handler *handler,
1468                                             const char *name)
1469 {
1470         char destroy[MAXPATHLEN];
1471         bool bret = true;
1472         int ret = 0;
1473         struct lxc_container *c;
1474         if (handler->conf->rootfs.path && handler->conf->rootfs.mount) {
1475                 bret = do_destroy_container(handler->conf);
1476                 if (!bret) {
1477                         ERROR("Error destroying rootfs for %s", name);
1478                         return;
1479                 }
1480         }
1481         INFO("Destroyed rootfs for %s", name);
1482
1483         ret = snprintf(destroy, MAXPATHLEN, "%s/%s", handler->lxcpath, name);
1484         if (ret < 0 || ret >= MAXPATHLEN) {
1485                 ERROR("Error printing path for %s", name);
1486                 ERROR("Error destroying directory for %s", name);
1487                 return;
1488         }
1489
1490         c = lxc_container_new(name, handler->lxcpath);
1491         if (c) {
1492                 if (container_disk_lock(c)) {
1493                         INFO("Could not update lxc_snapshots file");
1494                         lxc_container_put(c);
1495                 } else {
1496                         mod_all_rdeps(c, false);
1497                         container_disk_unlock(c);
1498                         lxc_container_put(c);
1499                 }
1500         }
1501
1502         if (am_unpriv())
1503                 ret = userns_exec_1(handler->conf, lxc_rmdir_onedev_wrapper, destroy);
1504         else
1505                 ret = lxc_rmdir_onedev(destroy, NULL);
1506
1507         if (ret < 0) {
1508                 ERROR("Error destroying directory for %s", name);
1509                 return;
1510         }
1511         INFO("Destroyed directory for %s", name);
1512 }
1513
1514 static int lxc_rmdir_onedev_wrapper(void *data)
1515 {
1516         char *arg = (char *) data;
1517         return lxc_rmdir_onedev(arg, NULL);
1518 }
1519
1520 static bool do_destroy_container(struct lxc_conf *conf) {
1521         if (am_unpriv()) {
1522                 if (userns_exec_1(conf, bdev_destroy_wrapper, conf) < 0)
1523                         return false;
1524                 return true;
1525         }
1526         return bdev_destroy(conf);
1527 }