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("kill(-1, SIGSTOP) failed: %m");
 112
 113         n_processes = killall(sign);
 114
 115         if (kill(-1, SIGCONT) < 0)
 116                 log_warning("kill(-1, SIGCONT) failed: %m");
 117
 118         if (n_processes <= 0)
 119                 goto finish;
 120
 121         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 122         for (;;) {
 123                 int k;
 124                 usec_t n = now(CLOCK_MONOTONIC);
 125
 126                 for (;;) {
 127                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 128
 129                         if (pid == 0)
 130                                 break;
 131                         else if (pid < 0 && errno == ECHILD) {
 132                                 n_processes = 0;
 133                                 goto finish;
 134                         }
 135
 136                         if (--n_processes == 0)
 137                                 goto finish;
 138                 }
 139
 140                 if (n >= until)
 141                         goto finish;
 142
 143                 timespec_store(&ts, until - n);
 144                 if ((k = sigtimedwait(&mask, NULL, &ts)) != SIGCHLD) {
 145                         if (k >= 0)
 146                                 log_warning("sigtimedwait() returned unexpected signal.");
 147                         if (k < 0 && errno != EAGAIN)
 148                                 log_warning("sigtimedwait() failed: %m");
 149                 }
 150         }
 151
 152 finish:
 153         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 154
 155         return n_processes;
 156 }
 157
 158 static int rescue_send_signal(int sign) {
 159         sigset_t mask, oldmask;
 160         usec_t until;
 161         struct timespec ts;
 162         int r;
 163
 164         sigemptyset(&mask);
 165         sigaddset(&mask, SIGCHLD);
 166         if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
 167                 return -errno;
 168
 169         if (kill(-1, SIGSTOP) < 0)
 170                 log_warning("kill(-1, SIGSTOP) failed: %m");
 171
 172         r = kill(-1, sign);
 173         if (r < 0)
 174                 log_warning("kill(-1, %d) failed: %m", sign);
 175
 176         if (kill(-1, SIGCONT) < 0)
 177                 log_warning("kill(-1, SIGCONT) failed: %m");
 178
 179         if (r < 0)
 180                 goto finish;
 181
 182         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 183         for (;;) {
 184                 int k;
 185                 usec_t n = now(CLOCK_MONOTONIC);
 186
 187                 for (;;) {
 188                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 189                         if (pid == 0)
 190                                 break;
 191                         else if (pid < 0 && errno == ECHILD)
 192                                 goto finish;
 193                 }
 194
 195                 if (n >= until)
 196                         goto finish;
 197
 198                 timespec_store(&ts, until - n);
 199                 if ((k = sigtimedwait(&mask, NULL, &ts)) != SIGCHLD) {
 200                         if (k >= 0)
 201                                 log_warning("sigtimedwait() returned unexpected signal.");
 202                         if (k < 0 && errno != EAGAIN)
 203                                 log_warning("sigtimedwait() failed: %m");
 204                 }
 205         }
 206
 207 finish:
 208         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 209
 210         return r;
 211 }
 212
 213 int main(int argc, char *argv[]) {
 214         int cmd, r;
 215         unsigned retries;
 216         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
 217         bool killed_everbody = false;
 218
 219         log_parse_environment();
 220         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
 221         log_open();
 222
 223         if (getpid() != 1) {
 224                 log_error("Not executed by init (pid 1).");
 225                 r = -EPERM;
 226                 goto error;
 227         }
 228
 229         if (argc != 2) {
 230                 log_error("Invalid number of arguments.");
 231                 r = -EINVAL;
 232                 goto error;
 233         }
 234
 235         if (streq(argv[1], "reboot"))
 236                 cmd = RB_AUTOBOOT;
 237         else if (streq(argv[1], "poweroff"))
 238                 cmd = RB_POWER_OFF;
 239         else if (streq(argv[1], "halt"))
 240                 cmd = RB_HALT_SYSTEM;
 241         else if (streq(argv[1], "kexec"))
 242                 cmd = LINUX_REBOOT_CMD_KEXEC;
 243         else {
 244                 log_error("Unknown action '%s'.", argv[1]);
 245                 r = -EINVAL;
 246                 goto error;
 247         }
 248
 249         /* lock us into memory */
 250         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
 251                 log_warning("Cannot lock process memory: %m");
 252
 253         log_info("Sending SIGTERM to remaining processes...");
 254         r = send_signal(SIGTERM);
 255         if (r < 0)
 256                 log_warning("Failed to send SIGTERM to remaining processes: %s", strerror(r));
 257
 258         log_info("Sending SIGKILL to remaining processes...");
 259         r = send_signal(SIGKILL);
 260         if (r < 0)
 261                 log_warning("Failed to send SIGKILL to remaining processes: %s", strerror(r));
 262
 263         /* Unmount all mountpoints, swaps, and loopback devices */
 264         for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
 265                 bool changed = false;
 266
 267                 if (need_umount) {
 268                         log_info("Unmounting file systems.");
 269                         r = umount_all(&changed);
 270                         if (r == 0)
 271                                 need_umount = false;
 272                         else if (r > 0)
 273                                 log_info("Not all file systems unmounted, %d left.", r);
 274                         else
 275                                 log_error("Failed to unmount file systems: %s", strerror(-r));
 276                 }
 277
 278                 if (need_swapoff) {
 279                         log_info("Disabling swaps.");
 280                         r = swapoff_all(&changed);
 281                         if (r == 0)
 282                                 need_swapoff = false;
 283                         else if (r > 0)
 284                                 log_info("Not all swaps are turned off, %d left.", r);
 285                         else
 286                                 log_error("Failed to turn off swaps: %s", strerror(-r));
 287                 }
 288
 289                 if (need_loop_detach) {
 290                         log_info("Detaching loop devices.");
 291                         r = loopback_detach_all(&changed);
 292                         if (r == 0)
 293                                 need_loop_detach = false;
 294                         else if (r > 0)
 295                                 log_info("Not all loop devices detached, %d left.", r);
 296                         else
 297                                 log_error("Failed to detach loop devices: %s", strerror(-r));
 298                 }
 299
 300                 if (need_dm_detach) {
 301                         log_info("Detaching DM devices.");
 302                         r = dm_detach_all(&changed);
 303                         if (r == 0)
 304                                 need_dm_detach = false;
 305                         else if (r > 0)
 306                                 log_warning("Not all DM devices detached, %d left.", r);
 307                         else
 308                                 log_error("Failed to detach DM devices: %s", strerror(-r));
 309                 }
 310
 311                 if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach)
 312                         /* Yay, done */
 313                         break;
 314
 315                 /* If in this iteration we didn't manage to
 316                  * unmount/deactivate anything, we either kill more
 317                  * processes, or simply give up */
 318                 if (!changed) {
 319
 320                         if (killed_everbody) {
 321                                 /* Hmm, we already killed everybody,
 322                                  * let's just give up */
 323                                 log_error("Cannot finalize remaining file systems and devices, giving up.");
 324                                 break;
 325                         }
 326
 327                         log_warning("Cannot finalize remaining file systems and devices, trying to kill remaining processes.");
 328                         rescue_send_signal(SIGTERM);
 329                         rescue_send_signal(SIGKILL);
 330                         killed_everbody = true;
 331                 }
 332
 333                 log_debug("Couldn't finalize remaining file systems and devices after %u retries, trying again.", retries+1);
 334         }
 335
 336         if (retries >= FINALIZE_ATTEMPTS)
 337                 log_error("Too many iterations, giving up.");
 338
 339         execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, NULL);
 340
 341         sync();
 342
 343         if (cmd == LINUX_REBOOT_CMD_KEXEC) {
 344                 /* We cheat and exec kexec to avoid doing all its work */
 345                 pid_t pid = fork();
 346
 347                 if (pid < 0)
 348                         log_error("Could not fork: %m. Falling back to normal reboot.");
 349                 else if (pid > 0) {
 350                         wait_for_terminate_and_warn("kexec", pid);
 351                         log_warning("kexec failed. Falling back to normal reboot.");
 352                 } else {
 353                         /* Child */
 354                         const char *args[3] = { "/sbin/kexec", "-e", NULL };
 355                         execv(args[0], (char * const *) args);
 356                         return EXIT_FAILURE;
 357                 }
 358
 359                 cmd = RB_AUTOBOOT;
 360         }
 361
 362         reboot(cmd);
 363         log_error("Failed to invoke reboot(): %m");
 364         r = -errno;
 365
 366   error:
 367         log_error("Critical error while doing system shutdown: %s", strerror(-r));
 368
 369         freeze();
 370         return EXIT_FAILURE;
 371 }