From 146de8175e11c877908f20f8ed1b5a3805455c0a Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 12 Apr 2012 14:18:36 +0200 Subject: shutdown: move shutdown to core since it replaces PID 1 --- src/core/shutdown.c | 492 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 492 insertions(+) create mode 100644 src/core/shutdown.c (limited to 'src/core/shutdown.c') diff --git a/src/core/shutdown.c b/src/core/shutdown.c new file mode 100644 index 0000000000..cd478b0349 --- /dev/null +++ b/src/core/shutdown.c @@ -0,0 +1,492 @@ +/*-*- 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 . +***/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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(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; + + 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 */ + if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0) + log_warning("Cannot lock process memory: %m"); + + 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; + + /* 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."); + + execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, NULL); + + /* 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; +} -- cgit v1.2.3-54-g00ecf