498 lines
16 KiB
C
498 lines
16 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 ProFUSION embedded systems
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/reboot.h>
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#include <linux/reboot.h>
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#include <sys/wait.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mount.h>
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#include <sys/syscall.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <errno.h>
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#include <unistd.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include "missing.h"
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#include "log.h"
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#include "umount.h"
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#include "util.h"
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#include "mkdir.h"
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#include "virt.h"
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#include "watchdog.h"
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#define TIMEOUT_USEC (5 * USEC_PER_SEC)
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#define FINALIZE_ATTEMPTS 50
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static bool ignore_proc(pid_t pid) {
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char buf[PATH_MAX];
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FILE *f;
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char c;
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size_t count;
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uid_t uid;
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int r;
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/* We are PID 1, let's not commit suicide */
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if (pid == 1)
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return true;
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r = get_process_uid(pid, &uid);
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if (r < 0)
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return true; /* not really, but better safe than sorry */
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/* Non-root processes otherwise are always subject to be killed */
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if (uid != 0)
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return false;
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snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long) pid);
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char_array_0(buf);
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f = fopen(buf, "re");
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if (!f)
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return true; /* not really, but has the desired effect */
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count = fread(&c, 1, 1, f);
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fclose(f);
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/* Kernel threads have an empty cmdline */
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if (count <= 0)
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return true;
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/* Processes with argv[0][0] = '@' we ignore from the killing
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* spree.
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*
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* http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons */
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if (count == 1 && c == '@')
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return true;
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return false;
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}
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static int killall(int sign) {
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DIR *dir;
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struct dirent *d;
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unsigned int n_processes = 0;
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dir = opendir("/proc");
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if (!dir)
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return -errno;
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while ((d = readdir(dir))) {
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pid_t pid;
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if (parse_pid(d->d_name, &pid) < 0)
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continue;
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if (ignore_proc(pid))
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continue;
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if (kill(pid, sign) == 0)
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n_processes++;
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else
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log_warning("Could not kill %d: %m", pid);
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}
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closedir(dir);
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return n_processes;
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}
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static void wait_for_children(int n_processes, sigset_t *mask) {
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usec_t until;
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assert(mask);
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until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
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for (;;) {
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struct timespec ts;
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int k;
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usec_t n;
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for (;;) {
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pid_t pid = waitpid(-1, NULL, WNOHANG);
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if (pid == 0)
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break;
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if (pid < 0 && errno == ECHILD)
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return;
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if (n_processes > 0)
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if (--n_processes == 0)
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return;
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}
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n = now(CLOCK_MONOTONIC);
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if (n >= until)
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return;
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timespec_store(&ts, until - n);
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if ((k = sigtimedwait(mask, NULL, &ts)) != SIGCHLD) {
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if (k < 0 && errno != EAGAIN) {
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log_error("sigtimedwait() failed: %m");
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return;
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}
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if (k >= 0)
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log_warning("sigtimedwait() returned unexpected signal.");
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}
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}
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}
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static void send_signal(int sign) {
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sigset_t mask, oldmask;
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int n_processes;
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assert_se(sigemptyset(&mask) == 0);
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assert_se(sigaddset(&mask, SIGCHLD) == 0);
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assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
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if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGSTOP) failed: %m");
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n_processes = killall(sign);
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if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGCONT) failed: %m");
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if (n_processes <= 0)
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goto finish;
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wait_for_children(n_processes, &mask);
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finish:
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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}
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static void ultimate_send_signal(int sign) {
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sigset_t mask, oldmask;
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int r;
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assert_se(sigemptyset(&mask) == 0);
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assert_se(sigaddset(&mask, SIGCHLD) == 0);
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assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
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if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGSTOP) failed: %m");
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r = kill(-1, sign);
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if (r < 0 && errno != ESRCH)
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log_warning("kill(-1, %s) failed: %m", signal_to_string(sign));
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if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
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log_warning("kill(-1, SIGCONT) failed: %m");
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if (r < 0)
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goto finish;
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wait_for_children(0, &mask);
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finish:
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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}
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static int prepare_new_root(void) {
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static const char dirs[] =
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"/run/initramfs/oldroot\0"
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"/run/initramfs/proc\0"
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"/run/initramfs/sys\0"
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"/run/initramfs/dev\0"
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"/run/initramfs/run\0";
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const char *dir;
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if (mount("/run/initramfs", "/run/initramfs", NULL, MS_BIND, NULL) < 0) {
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log_error("Failed to mount bind /run/initramfs on /run/initramfs: %m");
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return -errno;
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}
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if (mount(NULL, "/run/initramfs", NULL, MS_PRIVATE, NULL) < 0) {
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log_error("Failed to make /run/initramfs private mount: %m");
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return -errno;
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}
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NULSTR_FOREACH(dir, dirs)
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if (mkdir_p(dir, 0755) < 0 && errno != EEXIST) {
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log_error("Failed to mkdir %s: %m", dir);
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return -errno;
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}
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if (mount("/sys", "/run/initramfs/sys", NULL, MS_BIND, NULL) < 0) {
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log_error("Failed to mount bind /sys on /run/initramfs/sys: %m");
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return -errno;
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}
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if (mount("/proc", "/run/initramfs/proc", NULL, MS_BIND, NULL) < 0) {
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log_error("Failed to mount bind /proc on /run/initramfs/proc: %m");
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return -errno;
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}
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if (mount("/dev", "/run/initramfs/dev", NULL, MS_BIND, NULL) < 0) {
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log_error("Failed to mount bind /dev on /run/initramfs/dev: %m");
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return -errno;
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}
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if (mount("/run", "/run/initramfs/run", NULL, MS_BIND, NULL) < 0) {
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log_error("Failed to mount bind /run on /run/initramfs/run: %m");
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return -errno;
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}
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return 0;
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}
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static int pivot_to_new_root(void) {
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int fd;
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chdir("/run/initramfs");
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/*
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In case some evil process made "/" MS_SHARED
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It works for pivot_root, but the ref count for the root device
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is not decreasing :-/
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*/
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if (mount(NULL, "/", NULL, MS_PRIVATE, NULL) < 0) {
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log_error("Failed to make \"/\" private mount %m");
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return -errno;
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}
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if (pivot_root(".", "oldroot") < 0) {
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log_error("pivot failed: %m");
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/* only chroot if pivot root succeded */
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return -errno;
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}
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chroot(".");
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log_info("Successfully changed into root pivot.");
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fd = open("/dev/console", O_RDWR);
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if (fd < 0)
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log_error("Failed to open /dev/console: %m");
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else {
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make_stdio(fd);
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/* Initialize the controlling terminal */
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setsid();
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ioctl(STDIN_FILENO, TIOCSCTTY, NULL);
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}
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return 0;
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}
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int main(int argc, char *argv[]) {
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int cmd, r;
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unsigned retries;
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bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
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bool killed_everbody = false, in_container, use_watchdog = false;
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char *arguments[3];
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log_parse_environment();
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log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
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log_open();
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umask(0022);
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if (getpid() != 1) {
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log_error("Not executed by init (pid 1).");
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r = -EPERM;
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goto error;
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}
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if (argc != 2) {
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log_error("Invalid number of arguments.");
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r = -EINVAL;
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goto error;
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}
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in_container = detect_container(NULL) > 0;
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if (streq(argv[1], "reboot"))
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cmd = RB_AUTOBOOT;
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else if (streq(argv[1], "poweroff"))
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cmd = RB_POWER_OFF;
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else if (streq(argv[1], "halt"))
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cmd = RB_HALT_SYSTEM;
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else if (streq(argv[1], "kexec"))
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cmd = LINUX_REBOOT_CMD_KEXEC;
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else {
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log_error("Unknown action '%s'.", argv[1]);
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r = -EINVAL;
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goto error;
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}
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use_watchdog = !!getenv("WATCHDOG_USEC");
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/* lock us into memory */
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mlockall(MCL_CURRENT|MCL_FUTURE);
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log_info("Sending SIGTERM to remaining processes...");
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send_signal(SIGTERM);
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log_info("Sending SIGKILL to remaining processes...");
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send_signal(SIGKILL);
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if (in_container) {
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need_swapoff = false;
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need_dm_detach = false;
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}
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/* Unmount all mountpoints, swaps, and loopback devices */
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for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
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bool changed = false;
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if (use_watchdog)
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watchdog_ping();
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if (need_umount) {
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log_info("Unmounting file systems.");
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r = umount_all(&changed);
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if (r == 0)
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need_umount = false;
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else if (r > 0)
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log_info("Not all file systems unmounted, %d left.", r);
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else
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log_error("Failed to unmount file systems: %s", strerror(-r));
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}
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if (need_swapoff) {
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log_info("Disabling swaps.");
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r = swapoff_all(&changed);
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if (r == 0)
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need_swapoff = false;
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else if (r > 0)
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log_info("Not all swaps are turned off, %d left.", r);
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else
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log_error("Failed to turn off swaps: %s", strerror(-r));
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}
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if (need_loop_detach) {
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log_info("Detaching loop devices.");
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r = loopback_detach_all(&changed);
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if (r == 0)
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need_loop_detach = false;
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else if (r > 0)
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log_info("Not all loop devices detached, %d left.", r);
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else
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log_error("Failed to detach loop devices: %s", strerror(-r));
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}
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if (need_dm_detach) {
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log_info("Detaching DM devices.");
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r = dm_detach_all(&changed);
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if (r == 0)
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need_dm_detach = false;
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else if (r > 0)
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log_warning("Not all DM devices detached, %d left.", r);
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else
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log_error("Failed to detach DM devices: %s", strerror(-r));
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}
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if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach) {
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if (retries > 0)
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log_info("All filesystems, swaps, loop devices, DM devices detached.");
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/* Yay, done */
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break;
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}
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/* If in this iteration we didn't manage to
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* unmount/deactivate anything, we either kill more
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* processes, or simply give up */
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if (!changed) {
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if (killed_everbody) {
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/* Hmm, we already killed everybody,
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* let's just give up */
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log_error("Cannot finalize remaining file systems and devices, giving up.");
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break;
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}
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log_warning("Cannot finalize remaining file systems and devices, trying to kill remaining processes.");
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ultimate_send_signal(SIGTERM);
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ultimate_send_signal(SIGKILL);
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killed_everbody = true;
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}
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log_debug("Couldn't finalize remaining file systems and devices after %u retries, trying again.", retries+1);
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}
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if (retries >= FINALIZE_ATTEMPTS)
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log_error("Too many iterations, giving up.");
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arguments[0] = NULL;
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arguments[1] = argv[1];
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arguments[2] = NULL;
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execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, arguments);
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/* If we are in a container, just exit, this will kill our
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* container for good. */
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if (in_container) {
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log_error("Exiting container.");
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exit(0);
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}
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if (access("/run/initramfs/shutdown", X_OK) == 0) {
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if (prepare_new_root() >= 0 &&
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pivot_to_new_root() >= 0) {
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execv("/shutdown", argv);
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log_error("Failed to execute shutdown binary: %m");
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}
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}
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sync();
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if (cmd == LINUX_REBOOT_CMD_KEXEC) {
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/* We cheat and exec kexec to avoid doing all its work */
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pid_t pid = fork();
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if (pid < 0)
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log_error("Could not fork: %m. Falling back to normal reboot.");
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else if (pid > 0) {
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wait_for_terminate_and_warn("kexec", pid);
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log_warning("kexec failed. Falling back to normal reboot.");
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} else {
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/* Child */
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const char *args[3] = { "/sbin/kexec", "-e", NULL };
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execv(args[0], (char * const *) args);
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return EXIT_FAILURE;
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}
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cmd = RB_AUTOBOOT;
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}
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reboot(cmd);
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log_error("Failed to invoke reboot(): %m");
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r = -errno;
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error:
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log_error("Critical error while doing system shutdown: %s", strerror(-r));
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freeze();
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return EXIT_FAILURE;
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}
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