shutdown.c revision d2e54fae5ca7a0f71b5ac8b356a589ff0a09ea0a
/*-*- 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"
#define TIMEOUT_USEC (5 * USEC_PER_SEC)
#define FINALIZE_ATTEMPTS 50
static bool ignore_proc(pid_t pid) {
char buf[PATH_MAX];
FILE *f;
char c;
size_t count;
uid_t uid;
int r;
/* We are PID 1, let's not commit suicide */
if (pid == 1)
return true;
r = get_process_uid(pid, &uid);
if (r < 0)
return true; /* not really, but better safe than sorry */
/* Non-root processes otherwise are always subject to be killed */
if (uid != 0)
return false;
snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long) pid);
char_array_0(buf);
f = fopen(buf, "re");
if (!f)
return true; /* not really, but has the desired effect */
count = fread(&c, 1, 1, f);
fclose(f);
/* Kernel threads have an empty cmdline */
if (count <= 0)
return true;
/* Processes with argv[0][0] = '@' we ignore from the killing
* spree.
*
* http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */
if (count == 1 && c == '@')
return true;
return false;
}
static int killall(int sign) {
DIR *dir;
struct dirent *d;
unsigned int n_processes = 0;
dir = opendir("/proc");
if (!dir)
return -errno;
while ((d = readdir(dir))) {
pid_t pid;
if (parse_pid(d->d_name, &pid) < 0)
continue;
if (ignore_proc(pid))
continue;
if (kill(pid, sign) == 0)
n_processes++;
else
log_warning("Could not kill %d: %m", pid);
}
closedir(dir);
return n_processes;
}
static void wait_for_children(int n_processes, sigset_t *mask) {
usec_t until;
assert(mask);
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
struct timespec ts;
int k;
usec_t n;
for (;;) {
pid_t pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
if (pid < 0 && errno == ECHILD)
return;
if (n_processes > 0)
if (--n_processes == 0)
return;
}
n = now(CLOCK_MONOTONIC);
if (n >= until)
return;
timespec_store(&ts, until - n);
if ((k = sigtimedwait(mask, NULL, &ts)) != SIGCHLD) {
if (k < 0 && errno != EAGAIN) {
log_error("sigtimedwait() failed: %m");
return;
}
if (k >= 0)
log_warning("sigtimedwait() returned unexpected signal.");
}
}
}
static void send_signal(int sign) {
sigset_t mask, oldmask;
int n_processes;
assert_se(sigemptyset(&mask) == 0);
assert_se(sigaddset(&mask, SIGCHLD) == 0);
assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGSTOP) failed: %m");
n_processes = killall(sign);
if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGCONT) failed: %m");
if (n_processes <= 0)
goto finish;
wait_for_children(n_processes, &mask);
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
}
static void ultimate_send_signal(int sign) {
sigset_t mask, oldmask;
int r;
assert_se(sigemptyset(&mask) == 0);
assert_se(sigaddset(&mask, SIGCHLD) == 0);
assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGSTOP) failed: %m");
r = kill(-1, sign);
if (r < 0 && errno != ESRCH)
log_warning("kill(-1, %s) failed: %m", signal_to_string(sign));
if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
log_warning("kill(-1, SIGCONT) failed: %m");
if (r < 0)
goto finish;
wait_for_children(0, &mask);
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
}
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) {
int fd;
chdir("/run/initramfs");
/*
In case some evil process made "/" MS_SHARED
It works for pivot_root, but the ref count for the root device
is not decreasing :-/
*/
if (mount(NULL, "/", NULL, MS_PRIVATE, NULL) < 0) {
log_error("Failed to make \"/\" private mount %m");
return -errno;
}
if (pivot_root(".", "oldroot") < 0) {
log_error("pivot failed: %m");
/* only chroot if pivot root succeded */
return -errno;
}
chroot(".");
log_info("Successfully changed into root pivot.");
fd = open("/dev/console", O_RDWR);
if (fd < 0)
log_error("Failed to open /dev/console: %m");
else {
make_stdio(fd);
/* Initialize the controlling terminal */
setsid();
ioctl(STDIN_FILENO, TIOCSCTTY, NULL);
}
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 killed_everbody = false, 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...");
send_signal(SIGTERM);
log_info("Sending SIGKILL to remaining processes...");
send_signal(SIGKILL);
if (in_container) {
need_swapoff = false;
need_dm_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_warning("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 either kill more
* processes, or simply give up */
if (!changed) {
if (killed_everbody) {
/* Hmm, we already killed everybody,
* let's just give up */
log_error("Cannot finalize remaining file systems and devices, giving up.");
break;
}
log_warning("Cannot finalize remaining file systems and devices, trying to kill remaining processes.");
ultimate_send_signal(SIGTERM);
ultimate_send_signal(SIGKILL);
killed_everbody = true;
}
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 we are in a container, just exit, this will kill our
* container for good. */
if (in_container) {
log_error("Exiting container.");
exit(0);
}
if (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");
}
}
sync();
if (cmd == LINUX_REBOOT_CMD_KEXEC) {
/* 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);
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;
}