shutdown.c revision 35b8ca3aaf8cb044ad76675dfcad89e000dd4a5c
/*-*- 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 General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU 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 <dirent.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "log.h"
#include "umount.h"
#include "util.h"
#define TIMEOUT_USEC (5 * USEC_PER_SEC)
#define FINALIZE_ATTEMPTS 50
static bool ignore_proc(pid_t pid) {
if (pid == 1)
return true;
/* TODO: add more ignore rules here: device-mapper, etc */
return false;
}
static bool is_kernel_thread(pid_t pid)
{
char buf[PATH_MAX];
FILE *f;
char c;
size_t count;
snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long)pid);
f = fopen(buf, "re");
if (!f)
return true; /* not really, but has the desired effect */
count = fread(&c, 1, 1, f);
fclose(f);
return count != 1;
}
static int killall(int sign) {
DIR *dir;
struct dirent *d;
unsigned int n_processes = 0;
if ((dir = opendir("/proc")) == NULL)
return -errno;
while ((d = readdir(dir))) {
pid_t pid;
if (parse_pid(d->d_name, &pid) < 0)
continue;
if (is_kernel_thread(pid))
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 int send_signal(int sign) {
sigset_t mask, oldmask;
usec_t until;
int n_processes;
struct timespec ts;
assert_se(sigemptyset(&mask) == 0);
assert_se(sigaddset(&mask, SIGCHLD) == 0);
if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
return -errno;
if (kill(-1, SIGSTOP) < 0)
log_warning("kill(-1, SIGSTOP) failed: %m");
n_processes = killall(sign);
if (kill(-1, SIGCONT) < 0)
log_warning("kill(-1, SIGCONT) failed: %m");
if (n_processes <= 0)
goto finish;
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
int k;
usec_t n = now(CLOCK_MONOTONIC);
for (;;) {
pid_t pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
else if (pid < 0 && errno == ECHILD) {
n_processes = 0;
goto finish;
}
if (--n_processes == 0)
goto finish;
}
if (n >= until)
goto finish;
timespec_store(&ts, until - n);
if ((k = sigtimedwait(&mask, NULL, &ts)) != SIGCHLD) {
if (k >= 0)
log_warning("sigtimedwait() returned unexpected signal.");
if (k < 0 && errno != EAGAIN)
log_warning("sigtimedwait() failed: %m");
}
}
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return n_processes;
}
static int rescue_send_signal(int sign) {
sigset_t mask, oldmask;
usec_t until;
struct timespec ts;
int r;
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
return -errno;
if (kill(-1, SIGSTOP) < 0)
log_warning("kill(-1, SIGSTOP) failed: %m");
r = kill(-1, sign);
if (r < 0)
log_warning("kill(-1, %d) failed: %m", sign);
if (kill(-1, SIGCONT) < 0)
log_warning("kill(-1, SIGCONT) failed: %m");
if (r < 0)
goto finish;
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
int k;
usec_t n = now(CLOCK_MONOTONIC);
for (;;) {
pid_t pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
else if (pid < 0 && errno == ECHILD)
goto finish;
}
if (n >= until)
goto finish;
timespec_store(&ts, until - n);
if ((k = sigtimedwait(&mask, NULL, &ts)) != SIGCHLD) {
if (k >= 0)
log_warning("sigtimedwait() returned unexpected signal.");
if (k < 0 && errno != EAGAIN)
log_warning("sigtimedwait() failed: %m");
}
}
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return r;
}
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;
log_parse_environment();
log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
log_open();
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;
}
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;
}
/* lock us into memory */
if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
log_warning("Cannot lock process memory: %m");
log_info("Sending SIGTERM to remaining processes...");
r = send_signal(SIGTERM);
if (r < 0)
log_warning("Failed to send SIGTERM to remaining processes: %s", strerror(r));
log_info("Sending SIGKILL to remaining processes...");
r = send_signal(SIGKILL);
if (r < 0)
log_warning("Failed to send SIGKILL to remaining processes: %s", strerror(r));
/* Unmount all mountpoints, swaps, and loopback devices */
for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
bool changed = false;
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)
/* 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.");
rescue_send_signal(SIGTERM);
rescue_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.");
execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, NULL);
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;
}