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Systemd/src/core/shutdown.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 ProFUSION embedded systems
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/reboot.h>
#include <linux/reboot.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/syscall.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "missing.h"
#include "log.h"
#include "umount.h"
#include "util.h"
#include "mkdir.h"
#include "virt.h"
#include "watchdog.h"
#include "killall.h"
#define FINALIZE_ATTEMPTS 50
static int prepare_new_root(void) {
static const char dirs[] =
"/run/initramfs/oldroot\0"
"/run/initramfs/proc\0"
"/run/initramfs/sys\0"
"/run/initramfs/dev\0"
"/run/initramfs/run\0";
const char *dir;
if (mount("/run/initramfs", "/run/initramfs", NULL, MS_BIND, NULL) < 0) {
log_error("Failed to mount bind /run/initramfs on /run/initramfs: %m");
return -errno;
}
if (mount(NULL, "/run/initramfs", NULL, MS_PRIVATE, NULL) < 0) {
log_error("Failed to make /run/initramfs private mount: %m");
return -errno;
}
NULSTR_FOREACH(dir, dirs)
if (mkdir_p_label(dir, 0755) < 0 && errno != EEXIST) {
log_error("Failed to mkdir %s: %m", dir);
return -errno;
}
if (mount("/sys", "/run/initramfs/sys", NULL, MS_BIND, NULL) < 0) {
log_error("Failed to mount bind /sys on /run/initramfs/sys: %m");
return -errno;
}
if (mount("/proc", "/run/initramfs/proc", NULL, MS_BIND, NULL) < 0) {
log_error("Failed to mount bind /proc on /run/initramfs/proc: %m");
return -errno;
}
if (mount("/dev", "/run/initramfs/dev", NULL, MS_BIND, NULL) < 0) {
log_error("Failed to mount bind /dev on /run/initramfs/dev: %m");
return -errno;
}
if (mount("/run", "/run/initramfs/run", NULL, MS_BIND, NULL) < 0) {
log_error("Failed to mount bind /run on /run/initramfs/run: %m");
return -errno;
}
return 0;
}
static int pivot_to_new_root(void) {
if (chdir("/run/initramfs") < 0) {
log_error("Failed to change directory to /run/initramfs: %m");
return -errno;
}
/* Work-around for a kernel bug: for some reason the kernel
* refuses switching root if any file systems are mounted
* MS_SHARED. Hence remount them MS_PRIVATE here as a
* work-around.
*
* https://bugzilla.redhat.com/show_bug.cgi?id=847418 */
if (mount(NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL) < 0)
log_warning("Failed to make \"/\" private mount: %m");
if (pivot_root(".", "oldroot") < 0) {
log_error("pivot failed: %m");
/* only chroot if pivot root succeeded */
return -errno;
}
chroot(".");
setsid();
make_console_stdio();
log_info("Successfully changed into root pivot.");
return 0;
}
int main(int argc, char *argv[]) {
int cmd, r;
unsigned retries;
bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
bool in_container, use_watchdog = false;
char *arguments[3];
log_parse_environment();
log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
log_open();
umask(0022);
if (getpid() != 1) {
log_error("Not executed by init (pid 1).");
r = -EPERM;
goto error;
}
if (argc != 2) {
log_error("Invalid number of arguments.");
r = -EINVAL;
goto error;
}
in_container = detect_container(NULL) > 0;
if (streq(argv[1], "reboot"))
cmd = RB_AUTOBOOT;
else if (streq(argv[1], "poweroff"))
cmd = RB_POWER_OFF;
else if (streq(argv[1], "halt"))
cmd = RB_HALT_SYSTEM;
else if (streq(argv[1], "kexec"))
cmd = LINUX_REBOOT_CMD_KEXEC;
else {
log_error("Unknown action '%s'.", argv[1]);
r = -EINVAL;
goto error;
}
use_watchdog = !!getenv("WATCHDOG_USEC");
/* lock us into memory */
mlockall(MCL_CURRENT|MCL_FUTURE);
log_info("Sending SIGTERM to remaining processes...");
broadcast_signal(SIGTERM, true);
log_info("Sending SIGKILL to remaining processes...");
broadcast_signal(SIGKILL, true);
if (in_container) {
need_swapoff = false;
need_dm_detach = false;
need_loop_detach = false;
}
/* Unmount all mountpoints, swaps, and loopback devices */
for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
bool changed = false;
if (use_watchdog)
watchdog_ping();
if (need_umount) {
log_info("Unmounting file systems.");
r = umount_all(&changed);
if (r == 0)
need_umount = false;
else if (r > 0)
log_info("Not all file systems unmounted, %d left.", r);
else
log_error("Failed to unmount file systems: %s", strerror(-r));
}
if (need_swapoff) {
log_info("Disabling swaps.");
r = swapoff_all(&changed);
if (r == 0)
need_swapoff = false;
else if (r > 0)
log_info("Not all swaps are turned off, %d left.", r);
else
log_error("Failed to turn off swaps: %s", strerror(-r));
}
if (need_loop_detach) {
log_info("Detaching loop devices.");
r = loopback_detach_all(&changed);
if (r == 0)
need_loop_detach = false;
else if (r > 0)
log_info("Not all loop devices detached, %d left.", r);
else
log_error("Failed to detach loop devices: %s", strerror(-r));
}
if (need_dm_detach) {
log_info("Detaching DM devices.");
r = dm_detach_all(&changed);
if (r == 0)
need_dm_detach = false;
else if (r > 0)
log_info("Not all DM devices detached, %d left.", r);
else
log_error("Failed to detach DM devices: %s", strerror(-r));
}
if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach) {
if (retries > 0)
log_info("All filesystems, swaps, loop devices, DM devices detached.");
/* Yay, done */
break;
}
/* If in this iteration we didn't manage to
* unmount/deactivate anything, we simply give up */
if (!changed) {
log_error("Cannot finalize remaining file systems and devices, giving up.");
break;
}
log_debug("Couldn't finalize remaining file systems and devices after %u retries, trying again.", retries+1);
}
if (retries >= FINALIZE_ATTEMPTS)
log_error("Too many iterations, giving up.");
arguments[0] = NULL;
arguments[1] = argv[1];
arguments[2] = NULL;
execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, arguments);
if (!in_container && !in_initrd() &&
access("/run/initramfs/shutdown", X_OK) == 0) {
if (prepare_new_root() >= 0 &&
pivot_to_new_root() >= 0) {
execv("/shutdown", argv);
log_error("Failed to execute shutdown binary: %m");
}
}
/* The kernel will automaticall flush ATA disks and suchlike
* on reboot(), but the file systems need to be synce'd
* explicitly in advance. So let's do this here, but not
* needlessly slow down containers. */
if (!in_container)
sync();
if (cmd == LINUX_REBOOT_CMD_KEXEC) {
if (!in_container) {
/* We cheat and exec kexec to avoid doing all its work */
pid_t pid = fork();
if (pid < 0)
log_error("Could not fork: %m. Falling back to normal reboot.");
else if (pid > 0) {
wait_for_terminate_and_warn("kexec", pid);
log_warning("kexec failed. Falling back to normal reboot.");
} else {
/* Child */
const char *args[3] = { "/sbin/kexec", "-e", NULL };
execv(args[0], (char * const *) args);
return EXIT_FAILURE;
}
}
cmd = RB_AUTOBOOT;
}
reboot(cmd);
if (errno == EPERM && in_container) {
/* If we are in a container, and we lacked
* CAP_SYS_BOOT just exit, this will kill our
* container for good. */
log_error("Exiting container.");
exit(0);
}
log_error("Failed to invoke reboot(): %m");
r = -errno;
error:
log_error("Critical error while doing system shutdown: %s", strerror(-r));
freeze();
return EXIT_FAILURE;
}
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