/*-*- 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 interations, giving up."); 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[5] = { "/sbin/kexec", "-e", "-f", "-x", 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: sync(); log_error("Critical error while doing system shutdown: %s", strerror(-r)); freeze(); return EXIT_FAILURE; }