shutdown: move shutdown to core since it replaces PID 1

1 files changed, 492 insertions, 0 deletions

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 <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;
+}