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 void wait_for_children(int n_processes, sigset_t *mask) {
 100         usec_t until;
 101
 102         assert(mask);
 103
 104         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 105         for (;;) {
 106                 struct timespec ts;
 107                 int k;
 108                 usec_t n;
 109
 110                 for (;;) {
 111                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 112
 113                         if (pid == 0)
 114                                 break;
 115
 116                         if (pid < 0 && errno == ECHILD)
 117                                 return;
 118
 119                         if (n_processes > 0)
 120                                 if (--n_processes == 0)
 121                                         return;
 122                 }
 123
 124                 n = now(CLOCK_MONOTONIC);
 125                 if (n >= until)
 126                         return;
 127
 128                 timespec_store(&ts, until - n);
 129
 130                 if ((k = sigtimedwait(mask, NULL, &ts)) != SIGCHLD) {
 131
 132                         if (k < 0 && errno != EAGAIN) {
 133                                 log_error("sigtimedwait() failed: %m");
 134                                 return;
 135                         }
 136
 137                         if (k >= 0)
 138                                 log_warning("sigtimedwait() returned unexpected signal.");
 139                 }
 140         }
 141 }
 142
 143 static void send_signal(int sign) {
 144         sigset_t mask, oldmask;
 145         int n_processes;
 146
 147         assert_se(sigemptyset(&mask) == 0);
 148         assert_se(sigaddset(&mask, SIGCHLD) == 0);
 149         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
 150
 151         if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
 152                 log_warning("kill(-1, SIGSTOP) failed: %m");
 153
 154         n_processes = killall(sign);
 155
 156         if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
 157                 log_warning("kill(-1, SIGCONT) failed: %m");
 158
 159         if (n_processes <= 0)
 160                 goto finish;
 161
 162         wait_for_children(n_processes, &mask);
 163
 164 finish:
 165         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 166 }
 167
 168 static void ultimate_send_signal(int sign) {
 169         sigset_t mask, oldmask;
 170         int r;
 171
 172         assert_se(sigemptyset(&mask) == 0);
 173         assert_se(sigaddset(&mask, SIGCHLD) == 0);
 174         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);
 175
 176         if (kill(-1, SIGSTOP) < 0 && errno != ESRCH)
 177                 log_warning("kill(-1, SIGSTOP) failed: %m");
 178
 179         r = kill(-1, sign);
 180         if (r < 0 && errno != ESRCH)
 181                 log_warning("kill(-1, %s) failed: %m", signal_to_string(sign));
 182
 183         if (kill(-1, SIGCONT) < 0 && errno != ESRCH)
 184                 log_warning("kill(-1, SIGCONT) failed: %m");
 185
 186         if (r < 0)
 187                 goto finish;
 188
 189         wait_for_children(0, &mask);
 190
 191 finish:
 192         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 193 }
 194
 195 int main(int argc, char *argv[]) {
 196         int cmd, r;
 197         unsigned retries;
 198         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
 199         bool killed_everbody = false, in_container;
 200
 201         log_parse_environment();
 202         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
 203         log_open();
 204
 205         if (getpid() != 1) {
 206                 log_error("Not executed by init (pid 1).");
 207                 r = -EPERM;
 208                 goto error;
 209         }
 210
 211         if (argc != 2) {
 212                 log_error("Invalid number of arguments.");
 213                 r = -EINVAL;
 214                 goto error;
 215         }
 216
 217         in_container = detect_container(NULL) > 0;
 218
 219         if (streq(argv[1], "reboot"))
 220                 cmd = RB_AUTOBOOT;
 221         else if (streq(argv[1], "poweroff"))
 222                 cmd = RB_POWER_OFF;
 223         else if (streq(argv[1], "halt"))
 224                 cmd = RB_HALT_SYSTEM;
 225         else if (streq(argv[1], "kexec"))
 226                 cmd = LINUX_REBOOT_CMD_KEXEC;
 227         else {
 228                 log_error("Unknown action '%s'.", argv[1]);
 229                 r = -EINVAL;
 230                 goto error;
 231         }
 232
 233         /* lock us into memory */
 234         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
 235                 log_warning("Cannot lock process memory: %m");
 236
 237         log_info("Sending SIGTERM to remaining processes...");
 238         send_signal(SIGTERM);
 239
 240         log_info("Sending SIGKILL to remaining processes...");
 241         send_signal(SIGKILL);
 242
 243         if (in_container)
 244                 need_swapoff = false;
 245
 246         /* Unmount all mountpoints, swaps, and loopback devices */
 247         for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
 248                 bool changed = false;
 249
 250                 if (need_umount) {
 251                         log_info("Unmounting file systems.");
 252                         r = umount_all(&changed);
 253                         if (r == 0)
 254                                 need_umount = false;
 255                         else if (r > 0)
 256                                 log_info("Not all file systems unmounted, %d left.", r);
 257                         else
 258                                 log_error("Failed to unmount file systems: %s", strerror(-r));
 259                 }
 260
 261                 if (need_swapoff) {
 262                         log_info("Disabling swaps.");
 263                         r = swapoff_all(&changed);
 264                         if (r == 0)
 265                                 need_swapoff = false;
 266                         else if (r > 0)
 267                                 log_info("Not all swaps are turned off, %d left.", r);
 268                         else
 269                                 log_error("Failed to turn off swaps: %s", strerror(-r));
 270                 }
 271
 272                 if (need_loop_detach) {
 273                         log_info("Detaching loop devices.");
 274                         r = loopback_detach_all(&changed);
 275                         if (r == 0)
 276                                 need_loop_detach = false;
 277                         else if (r > 0)
 278                                 log_info("Not all loop devices detached, %d left.", r);
 279                         else
 280                                 log_error("Failed to detach loop devices: %s", strerror(-r));
 281                 }
 282
 283                 if (need_dm_detach) {
 284                         log_info("Detaching DM devices.");
 285                         r = dm_detach_all(&changed);
 286                         if (r == 0)
 287                                 need_dm_detach = false;
 288                         else if (r > 0)
 289                                 log_warning("Not all DM devices detached, %d left.", r);
 290                         else
 291                                 log_error("Failed to detach DM devices: %s", strerror(-r));
 292                 }
 293
 294                 if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach)
 295                         /* Yay, done */
 296                         break;
 297
 298                 /* If in this iteration we didn't manage to
 299                  * unmount/deactivate anything, we either kill more
 300                  * processes, or simply give up */
 301                 if (!changed) {
 302
 303                         if (killed_everbody) {
 304                                 /* Hmm, we already killed everybody,
 305                                  * let's just give up */
 306                                 log_error("Cannot finalize remaining file systems and devices, giving up.");
 307                                 break;
 308                         }
 309
 310                         log_warning("Cannot finalize remaining file systems and devices, trying to kill remaining processes.");
 311                         ultimate_send_signal(SIGTERM);
 312                         ultimate_send_signal(SIGKILL);
 313                         killed_everbody = true;
 314                 }
 315
 316                 log_debug("Couldn't finalize remaining file systems and devices after %u retries, trying again.", retries+1);
 317         }
 318
 319         if (retries >= FINALIZE_ATTEMPTS)
 320                 log_error("Too many iterations, giving up.");
 321
 322         execute_directory(SYSTEM_SHUTDOWN_PATH, NULL, NULL);
 323
 324         /* If we are in a container, just exit, this will kill our
 325          * container for good. */
 326         if (in_container) {
 327                 log_error("Exiting container.");
 328                 exit(0);
 329         }
 330
 331         sync();
 332
 333         if (cmd == LINUX_REBOOT_CMD_KEXEC) {
 334                 /* We cheat and exec kexec to avoid doing all its work */
 335                 pid_t pid = fork();
 336
 337                 if (pid < 0)
 338                         log_error("Could not fork: %m. Falling back to normal reboot.");
 339                 else if (pid > 0) {
 340                         wait_for_terminate_and_warn("kexec", pid);
 341                         log_warning("kexec failed. Falling back to normal reboot.");
 342                 } else {
 343                         /* Child */
 344                         const char *args[3] = { "/sbin/kexec", "-e", NULL };
 345                         execv(args[0], (char * const *) args);
 346                         return EXIT_FAILURE;
 347                 }
 348
 349                 cmd = RB_AUTOBOOT;
 350         }
 351
 352         reboot(cmd);
 353         log_error("Failed to invoke reboot(): %m");
 354         r = -errno;
 355
 356   error:
 357         log_error("Critical error while doing system shutdown: %s", strerror(-r));
 358
 359         freeze();
 360         return EXIT_FAILURE;
 361 }