src/shutdown.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 ProFUSION embedded systems
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <sys/mman.h>
  23 #include <sys/types.h>
  24 #include <sys/reboot.h>
  25 #include <linux/reboot.h>
  26 #include <sys/wait.h>
  27 #include <dirent.h>
  28 #include <errno.h>
  29 #include <unistd.h>
  30 #include <signal.h>
  31 #include <stdbool.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "log.h"
  36 #include "umount.h"
  37 #include "util.h"
  38
  39 #define TIMEOUT_USEC (5 * USEC_PER_SEC)
  40 #define FINALIZE_ATTEMPTS 50
  41
  42 static bool ignore_proc(pid_t pid) {
  43         if (pid == 1)
  44                 return true;
  45
  46         /* TODO: add more ignore rules here: device-mapper, etc */
  47
  48         return false;
  49 }
  50
  51 static bool is_kernel_thread(pid_t pid)
  52 {
  53         char buf[PATH_MAX];
  54         FILE *f;
  55         char c;
  56         size_t count;
  57
  58         snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long)pid);
  59         f = fopen(buf, "re");
  60         if (!f)
  61                 return true; /* not really, but has the desired effect */
  62
  63         count = fread(&c, 1, 1, f);
  64         fclose(f);
  65         return count != 1;
  66 }
  67
  68 static int killall(int sign) {
  69         DIR *dir;
  70         struct dirent *d;
  71         unsigned int n_processes = 0;
  72
  73         if ((dir = opendir("/proc")) == NULL)
  74                 return -errno;
  75
  76         while ((d = readdir(dir))) {
  77                 pid_t pid;
  78
  79                 if (parse_pid(d->d_name, &pid) < 0)
  80                         continue;
  81
  82                 if (is_kernel_thread(pid))
  83                         continue;
  84
  85                 if (ignore_proc(pid))
  86                         continue;
  87
  88                 if (kill(pid, sign) == 0)
  89                         n_processes++;
  90                 else
  91                         log_warning("Could not kill %d: %m", pid);
  92         }
  93
  94         closedir(dir);
  95
  96         return n_processes;
  97 }
  98
  99 static int send_signal(int sign) {
 100         sigset_t mask, oldmask;
 101         usec_t until;
 102         int n_processes;
 103         struct timespec ts;
 104
 105         assert_se(sigemptyset(&mask) == 0);
 106         assert_se(sigaddset(&mask, SIGCHLD) == 0);
 107         if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
 108                 return -errno;
 109
 110         if (kill(-1, SIGSTOP) < 0)
 111                 log_warning("Failed kill(-1, SIGSTOP): %m");
 112
 113         n_processes = killall(sign);
 114
 115         if (kill(-1, SIGCONT) < 0)
 116                 log_warning("Failed kill(-1, SIGCONT): %m");
 117
 118         if (n_processes <= 0)
 119                 goto finish;
 120
 121         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 122         for (;;) {
 123                 usec_t n = now(CLOCK_MONOTONIC);
 124                 for (;;) {
 125                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 126
 127                         if (pid == 0)
 128                                 break;
 129                         else if (pid < 0 && errno == ECHILD) {
 130                                 n_processes = 0;
 131                                 goto finish;
 132                         }
 133
 134                         if (--n_processes == 0)
 135                                 goto finish;
 136                 }
 137
 138                 if (n >= until)
 139                         goto finish;
 140
 141                 timespec_store(&ts, until - n);
 142                 if (sigtimedwait(&mask, NULL, &ts) != SIGCHLD)
 143                         if (errno != EAGAIN)
 144                                 log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
 145         }
 146
 147 finish:
 148         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 149
 150         return n_processes;
 151 }
 152
 153 static int rescue_send_signal(int sign) {
 154         sigset_t mask, oldmask;
 155         usec_t until;
 156         struct timespec ts;
 157         int r;
 158
 159         sigemptyset(&mask);
 160         sigaddset(&mask, SIGCHLD);
 161         if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
 162                 return -errno;
 163
 164         if (kill(-1, SIGSTOP) < 0)
 165                 log_warning("Failed kill(-1, SIGSTOP): %m");
 166
 167         r = kill(-1, sign);
 168         if (r < 0)
 169                 log_warning("Failed kill(-1, %d): %m", sign);
 170
 171         if (kill(-1, SIGCONT) < 0)
 172                 log_warning("Failed kill(-1, SIGCONT): %m");
 173
 174         if (r < 0)
 175                 goto finish;
 176
 177         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 178         for (;;) {
 179                 usec_t n = now(CLOCK_MONOTONIC);
 180                 for (;;) {
 181                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 182                         if (pid == 0)
 183                                 break;
 184                         else if (pid < 0 && errno == ECHILD)
 185                                 goto finish;
 186                 }
 187
 188                 if (n >= until)
 189                         goto finish;
 190
 191                 timespec_store(&ts, until - n);
 192                 if (sigtimedwait(&mask, NULL, &ts) != SIGCHLD)
 193                         if (errno != EAGAIN)
 194                                 log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
 195         }
 196
 197 finish:
 198         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 199
 200         return r;
 201 }
 202
 203 int main(int argc, char *argv[]) {
 204         int cmd, r;
 205         unsigned retries;
 206         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
 207         bool killed_everbody = false;
 208
 209         log_parse_environment();
 210         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
 211         log_open();
 212
 213         if (getpid() != 1) {
 214                 log_error("Not executed by init (pid 1).");
 215                 r = -EPERM;
 216                 goto error;
 217         }
 218
 219         if (argc != 2) {
 220                 log_error("Invalid number of arguments.");
 221                 r = -EINVAL;
 222                 goto error;
 223         }
 224
 225         if (streq(argv[1], "reboot"))
 226                 cmd = RB_AUTOBOOT;
 227         else if (streq(argv[1], "poweroff"))
 228                 cmd = RB_POWER_OFF;
 229         else if (streq(argv[1], "halt"))
 230                 cmd = RB_HALT_SYSTEM;
 231         else if (streq(argv[1], "kexec"))
 232                 cmd = LINUX_REBOOT_CMD_KEXEC;
 233         else {
 234                 log_error("Unknown action '%s'.", argv[1]);
 235                 r = -EINVAL;
 236                 goto error;
 237         }
 238
 239         /* lock us into memory */
 240         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
 241                 log_warning("Cannot lock process memory: %m");
 242
 243         log_info("Sending SIGTERM to processes");
 244         r = send_signal(SIGTERM);
 245         if (r < 0)
 246                 log_warning("Cannot send SIGTERM to all process: %s", strerror(r));
 247
 248         log_info("Sending SIGKILL to processes");
 249         r = send_signal(SIGKILL);
 250         if (r < 0)
 251                 log_warning("Cannot send SIGKILL to all process: %s", strerror(r));
 252
 253         /* Unmount all mountpoints, swaps, and loopback devices */
 254         for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
 255                 bool changed = false;
 256
 257                 if (need_umount) {
 258                         log_info("Unmounting filesystems.");
 259                         r = umount_all(&changed);
 260                         if (r == 0)
 261                                 need_umount = false;
 262                         else if (r > 0)
 263                                 log_warning("Not all filesystems unmounted, %d left.", r);
 264                         else
 265                                 log_error("Error unmounting filesystems: %s", strerror(-r));
 266                 }
 267
 268                 if (need_swapoff) {
 269                         log_info("Disabling swaps.");
 270                         r = swapoff_all(&changed);
 271                         if (r == 0)
 272                                 need_swapoff = false;
 273                         else if (r > 0)
 274                                 log_warning("Not all swaps are off, %d left.", r);
 275                         else
 276                                 log_error("Error turning off swaps: %s", strerror(-r));
 277                 }
 278
 279                 if (need_loop_detach) {
 280                         log_info("Detaching loop devices.");
 281                         r = loopback_detach_all(&changed);
 282                         if (r == 0)
 283                                 need_loop_detach = false;
 284                         else if (r > 0)
 285                                 log_warning("Not all loop devices detached, %d left.", r);
 286                         else
 287                                 log_error("Error detaching loop devices: %s", strerror(-r));
 288                 }
 289
 290                 if (need_dm_detach) {
 291                         log_info("Detaching DM devices.");
 292                         r = dm_detach_all(&changed);
 293                         if (r == 0)
 294                                 need_dm_detach = false;
 295                         else if (r > 0)
 296                                 log_warning("Not all dm devices detached, %d left.", r);
 297                         else
 298                                 log_error("Error detaching dm devices: %s", strerror(-r));
 299                 }
 300
 301                 if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach)
 302                         /* Yay, done */
 303                         break;
 304
 305                 /* If in this iteration we didn't manage to
 306                  * unmount/deactivate anything, we either kill more
 307                  * processes, or simply give up */
 308                 if (!changed) {
 309
 310                         if (killed_everbody) {
 311                                 /* Hmm, we already killed everybody,
 312                                  * let's just give up */
 313                                 log_error("Cannot finalize all filesystems and devices, giving up.");
 314                                 break;
 315                         }
 316
 317                         log_warning("Cannot finalize filesystems and devices, trying to kill remaining processes.");
 318                         rescue_send_signal(SIGTERM);
 319                         rescue_send_signal(SIGKILL);
 320                         killed_everbody = true;
 321                 }
 322
 323                 log_debug("Couldn't finalize filesystems and devices after %u retries, trying again.", retries+1);
 324         }
 325
 326         if (retries >= FINALIZE_ATTEMPTS)
 327                 log_error("Too many interations, giving up.");
 328
 329         sync();
 330
 331         if (cmd == LINUX_REBOOT_CMD_KEXEC) {
 332                 /* We cheat and exec kexec to avoid doing all its work */
 333                 pid_t pid = fork();
 334
 335                 if (pid < 0)
 336                         log_error("Could not fork: %m. Falling back to normal reboot.");
 337                 else if (pid > 0) {
 338                         wait_for_terminate_and_warn("kexec", pid);
 339                         log_warning("kexec failed. Falling back to normal reboot.");
 340                 } else {
 341                         /* Child */
 342                         const char *args[5] = { KEXEC_BINARY_PATH, "-e", "-f", "-x", NULL };
 343                         execv(args[0], (char * const *) args);
 344                         return EXIT_FAILURE;
 345                 }
 346
 347                 cmd = RB_AUTOBOOT;
 348         }
 349
 350         reboot(cmd);
 351         log_error("Failed to invoke reboot(): %m");
 352         r = -errno;
 353
 354   error:
 355         sync();
 356         log_error("Critical error while doing system shutdown: %s", strerror(-r));
 357
 358         freeze();
 359         return EXIT_FAILURE;
 360 }