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shutdown: Adding binary to shutdown the system

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This functions are working as follows:
   - Send a SIGTERM to all processes that may be finished
   - Send a SIGKILL to all processes that still live and may be finished
   - Try to unmount all mount points
   - Try to remount read-only all mount points that can't be umounted
   - Umount all swap devices
   - Umount and detach all loopback devices
   - Call [poweroff|halt|reboot|kexec]

TODO:
   - Umount device-mapper.
   - Make log work. So far it is being useless as we do not parse
     /etc/systemd/system.conf, kernel command line but just
     environment, however we're executed by init and thus have no
     useful variables. Forcing it to target=kmsg/console and
     level=debug also does not produce any output, however writing to
     /dev/console does work (hack used during debug).
This commit is contained in:
Fabiano Fidencio 2010-10-07 04:24:41 -07:00 committed by Lennart Poettering
parent e347837975
commit b1b2a107d1
2 changed files with 362 additions and 0 deletions
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17
Makefile.am
View File

@ -35,6 +35,7 @@ tmpfilesdir=$(sysconfdir)/tmpfiles.d
# And these are the special ones for /
rootdir=@rootdir@
rootbindir=$(rootdir)/bin
rootsbindir=$(rootdir)/sbin
rootlibexecdir=$(rootdir)/lib/systemd
systemunitdir=$(rootdir)/lib/systemd/system
@ -50,9 +51,11 @@ AM_CPPFLAGS = \
-DSESSION_DATA_UNIT_PATH=\"$(sessionunitdir)\" \
-DCGROUP_AGENT_PATH=\"$(rootlibexecdir)/systemd-cgroups-agent\" \
-DSYSTEMD_BINARY_PATH=\"$(rootbindir)/systemd\" \
-DSYSTEMD_SHUTDOWN_BINARY_PATH=\"$(rootlibexecdir)/systemd-shutdown\" \
-DSYSTEMCTL_BINARY_PATH=\"$(rootbindir)/systemctl\" \
-DRUNTIME_DIR=\"$(localstatedir)/run\" \
-DRANDOM_SEED=\"$(localstatedir)/lib/random-seed\" \
-DKEXEC_BINARY_PATH=\"$(rootsbindir)/kexec\" \
-I $(top_srcdir)/src
if TARGET_GENTOO
@ -96,6 +99,7 @@ rootlibexec_PROGRAMS = \
systemd-update-utmp \
systemd-random-seed \
systemd-shutdownd \
systemd-shutdown \
systemd-modules-load \
systemd-remount-api-vfs \
systemd-kmsg-syslogd \
@ -639,6 +643,19 @@ systemd_shutdownd_CFLAGS = \
systemd_shutdownd_LDADD = \
libsystemd-basic.la
systemd_shutdown_SOURCES = \
src/mount-setup.c \
src/umount.c \
src/shutdown.c
systemd_shutdown_CFLAGS = \
$(AM_CFLAGS) \
$(UDEV_CFLAGS)
systemd_shutdown_LDADD = \
libsystemd-basic.la \
$(UDEV_LIBS)
systemd_modules_load_SOURCES = \
src/modules-load.c

345
src/shutdown.c Normal file
View File

@ -0,0 +1,345 @@
/*-*- 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
#define FINALIZE_CRITICAL_ATTEMPTS 10
_noreturn_ static void freeze(void) {
for (;;)
pause();
}
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 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)
processes++;
else
log_warning("Could not kill %d: %m", pid);
}
closedir(dir);
return processes;
}
static int send_signal(int sign) {
sigset_t mask, oldmask;
usec_t until;
int 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("Failed kill(-1, SIGSTOP): %m");
processes = killall(sign);
if (kill(-1, SIGCONT) < 0)
log_warning("Failed kill(-1, SIGCONT): %m");
if (processes <= 0)
goto finish;
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
usec_t n = now(CLOCK_MONOTONIC);
for (;;) {
pid_t pid = waitpid(-1, NULL, WNOHANG);
if (pid == 0)
break;
else if (pid < 0 && errno == ECHILD) {
processes = 0;
goto finish;
}
if (--processes == 0)
goto finish;
}
if (n >= until)
goto finish;
timespec_store(&ts, until - n);
if (sigtimedwait(&mask, NULL, &ts) != SIGCHLD)
log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
}
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return 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("Failed kill(-1, SIGSTOP): %m");
r = kill(-1, sign);
if (r < 0)
log_warning("Failed kill(-1, %d): %m", sign);
if (kill(-1, SIGCONT) < 0)
log_warning("Failed kill(-1, SIGCONT): %m");
if (r < 0)
goto finish;
until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
for (;;) {
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 (sigtimedwait(&mask, NULL, &ts) != SIGCHLD)
log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
}
finish:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return r;
}
int main(int argc, char *argv[]) {
int cmd, r, retries;
bool need_umount = true, need_swapoff = true, need_loop_detach = true;
log_parse_environment();
log_set_target(LOG_TARGET_KMSG); /* 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 processes");
r = send_signal(SIGTERM);
if (r < 0)
log_warning("Cannot send SIGTERM to all process: %s", strerror(r));
log_info("Sending SIGKILL to processes");
r = send_signal(SIGKILL);
if (r < 0)
log_warning("Cannot send SIGKILL to all process: %s", strerror(r));
/* preventing that we won't block umounts */
if (chdir("/") != 0)
log_warning("Cannot chdir(\"/\"): %m. Unmounts likely to fail.");
/* umount all mountpoints, swaps, and loopback devices */
retries = FINALIZE_ATTEMPTS;
while (need_umount || need_swapoff || need_loop_detach) {
if (need_umount) {
log_info("Unmounting filesystems.");
r = umount_all();
if (r == 0)
need_umount = false;
else if (r > 0)
log_warning("Not all filesystems unmounted, %d left.", r);
else
log_error("Error unmounting filesystems: %s", strerror(-r));
}
if (need_swapoff) {
log_info("Disabling swaps.");
r = swapoff_all();
if (r == 0)
need_swapoff = false;
else if (r > 0)
log_warning("Not all swaps are off, %d left.", r);
else
log_error("Error turning off swaps: %s", strerror(-r));
}
if (need_loop_detach) {
log_info("Detaching loop devices.");
r = loopback_detach_all();
if (r == 0)
need_loop_detach = false;
else if (r > 0)
log_warning("Not all loop devices detached, %d left.", r);
else
log_error("Error detaching loop devices: %s", strerror(-r));
}
if (need_umount || need_swapoff || need_loop_detach) {
retries--;
if (retries <= FINALIZE_CRITICAL_ATTEMPTS) {
log_warning("Approaching critical level to finalize filesystem and devices, try to kill all processes.");
rescue_send_signal(SIGTERM);
rescue_send_signal(SIGKILL);
}
if (retries > 0)
log_info("Action still required, %d tries left", retries);
else {
log_error("Tried enough but still action required need_umount=%d, need_swapoff=%d, need_loop_detach=%d", need_umount, need_swapoff, need_loop_detach);
r = -EBUSY;
goto error;
}
}
}
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 reboot.");
cmd = RB_AUTOBOOT;
} else if (pid > 0) {
waitpid(pid, NULL, 0);
log_warning("Failed %s -e -x -f. Falling back to reboot", KEXEC_BINARY_PATH);
cmd = RB_AUTOBOOT;
} else {
const char *args[5] = {KEXEC_BINARY_PATH, "-e", "-f", "-x", NULL};
execv(args[0], (char * const *) args);
return EXIT_FAILURE;
}
}
reboot(cmd);
r = errno;
error:
sync();
if (r < 0)
r = -r;
log_error("Critical error while doing system shutdown: %s", strerror(r));
freeze();
return 0;
}