/*-*- 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 <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 <sys/types.h> #include <sys/stat.h> #include <sys/mount.h> #include <sys/syscall.h> #include <fcntl.h> #include <dirent.h> #include <errno.h> #include <unistd.h> #include <signal.h> #include <stdbool.h> #include <stdlib.h> #include <string.h> #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; }