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 #define FINALIZE_CRITICAL_ATTEMPTS 10
  42
  43 static bool ignore_proc(pid_t pid) {
  44         if (pid == 1)
  45                 return true;
  46
  47         /* TODO: add more ignore rules here: device-mapper, etc */
  48
  49         return false;
  50 }
  51
  52 static bool is_kernel_thread(pid_t pid)
  53 {
  54         char buf[PATH_MAX];
  55         FILE *f;
  56         char c;
  57         size_t count;
  58
  59         snprintf(buf, sizeof(buf), "/proc/%lu/cmdline", (unsigned long)pid);
  60         f = fopen(buf, "re");
  61         if (!f)
  62                 return true; /* not really, but has the desired effect */
  63
  64         count = fread(&c, 1, 1, f);
  65         fclose(f);
  66         return count != 1;
  67 }
  68
  69 static int killall(int sign) {
  70         DIR *dir;
  71         struct dirent *d;
  72         unsigned int processes = 0;
  73
  74         if ((dir = opendir("/proc")) == NULL)
  75                 return -errno;
  76
  77         while ((d = readdir(dir))) {
  78                 pid_t pid;
  79
  80                 if (parse_pid(d->d_name, &pid) < 0)
  81                         continue;
  82
  83                 if (is_kernel_thread(pid))
  84                         continue;
  85
  86                 if (ignore_proc(pid))
  87                         continue;
  88
  89                 if (kill(pid, sign) == 0)
  90                         processes++;
  91                 else
  92                         log_warning("Could not kill %d: %m", pid);
  93         }
  94
  95         closedir(dir);
  96
  97         return processes;
  98 }
  99
 100 static int send_signal(int sign) {
 101         sigset_t mask, oldmask;
 102         usec_t until;
 103         int processes;
 104         struct timespec ts;
 105
 106         assert_se(sigemptyset(&mask) == 0);
 107         assert_se(sigaddset(&mask, SIGCHLD) == 0);
 108         if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
 109                 return -errno;
 110
 111         if (kill(-1, SIGSTOP) < 0)
 112                 log_warning("Failed kill(-1, SIGSTOP): %m");
 113
 114         processes = killall(sign);
 115
 116         if (kill(-1, SIGCONT) < 0)
 117                 log_warning("Failed kill(-1, SIGCONT): %m");
 118
 119         if (processes <= 0)
 120                 goto finish;
 121
 122         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 123         for (;;) {
 124                 usec_t n = now(CLOCK_MONOTONIC);
 125                 for (;;) {
 126                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 127                         if (pid == 0)
 128                                 break;
 129                         else if (pid < 0 && errno == ECHILD) {
 130                                 processes = 0;
 131                                 goto finish;
 132                         }
 133
 134                         if (--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                         log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
 144         }
 145
 146 finish:
 147         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 148
 149         return processes;
 150 }
 151
 152 static int rescue_send_signal(int sign) {
 153         sigset_t mask, oldmask;
 154         usec_t until;
 155         struct timespec ts;
 156         int r;
 157
 158         sigemptyset(&mask);
 159         sigaddset(&mask, SIGCHLD);
 160         if (sigprocmask(SIG_BLOCK, &mask, &oldmask) != 0)
 161                 return -errno;
 162
 163         if (kill(-1, SIGSTOP) < 0)
 164                 log_warning("Failed kill(-1, SIGSTOP): %m");
 165
 166         r = kill(-1, sign);
 167         if (r < 0)
 168                 log_warning("Failed kill(-1, %d): %m", sign);
 169
 170         if (kill(-1, SIGCONT) < 0)
 171                 log_warning("Failed kill(-1, SIGCONT): %m");
 172
 173         if (r < 0)
 174                 goto finish;
 175
 176         until = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 177         for (;;) {
 178                 usec_t n = now(CLOCK_MONOTONIC);
 179                 for (;;) {
 180                         pid_t pid = waitpid(-1, NULL, WNOHANG);
 181                         if (pid == 0)
 182                                 break;
 183                         else if (pid < 0 && errno == ECHILD)
 184                                 goto finish;
 185                 }
 186
 187                 if (n >= until)
 188                         goto finish;
 189
 190                 timespec_store(&ts, until - n);
 191                 if (sigtimedwait(&mask, NULL, &ts) != SIGCHLD)
 192                         log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
 193         }
 194
 195 finish:
 196         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 197
 198         return r;
 199 }
 200
 201 int main(int argc, char *argv[]) {
 202         int cmd, r, retries;
 203         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
 204
 205         log_parse_environment();
 206         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
 207         log_open();
 208
 209         if (getpid() != 1) {
 210                 log_error("Not executed by init (pid 1).");
 211                 r = -EPERM;
 212                 goto error;
 213         }
 214
 215         if (argc != 2) {
 216                 log_error("Invalid number of arguments.");
 217                 r = -EINVAL;
 218                 goto error;
 219         }
 220
 221         if (streq(argv[1], "reboot"))
 222                 cmd = RB_AUTOBOOT;
 223         else if (streq(argv[1], "poweroff"))
 224                 cmd = RB_POWER_OFF;
 225         else if (streq(argv[1], "halt"))
 226                 cmd = RB_HALT_SYSTEM;
 227         else if (streq(argv[1], "kexec"))
 228                 cmd = LINUX_REBOOT_CMD_KEXEC;
 229         else {
 230                 log_error("Unknown action '%s'.", argv[1]);
 231                 r = -EINVAL;
 232                 goto error;
 233         }
 234
 235         /* lock us into memory */
 236         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
 237                 log_warning("Cannot lock process memory: %m");
 238
 239         log_info("Sending SIGTERM to processes");
 240         r = send_signal(SIGTERM);
 241         if (r < 0)
 242                 log_warning("Cannot send SIGTERM to all process: %s", strerror(r));
 243
 244         log_info("Sending SIGKILL to processes");
 245         r = send_signal(SIGKILL);
 246         if (r < 0)
 247                 log_warning("Cannot send SIGKILL to all process: %s", strerror(r));
 248
 249         /* Unmount all mountpoints, swaps, and loopback devices */
 250         retries = FINALIZE_ATTEMPTS;
 251         for (;;) {
 252                 if (need_umount) {
 253                         log_info("Unmounting filesystems.");
 254                         r = umount_all();
 255                         if (r == 0)
 256                                 need_umount = false;
 257                         else if (r > 0)
 258                                 log_warning("Not all filesystems unmounted, %d left.", r);
 259                         else
 260                                 log_error("Error unmounting filesystems: %s", strerror(-r));
 261                 }
 262
 263                 if (need_swapoff) {
 264                         log_info("Disabling swaps.");
 265                         r = swapoff_all();
 266                         if (r == 0)
 267                                 need_swapoff = false;
 268                         else if (r > 0)
 269                                 log_warning("Not all swaps are off, %d left.", r);
 270                         else
 271                                 log_error("Error turning off swaps: %s", strerror(-r));
 272                 }
 273
 274                 if (need_loop_detach) {
 275                         log_info("Detaching loop devices.");
 276                         r = loopback_detach_all();
 277                         if (r == 0)
 278                                 need_loop_detach = false;
 279                         else if (r > 0)
 280                                 log_warning("Not all loop devices detached, %d left.", r);
 281                         else
 282                                 log_error("Error detaching loop devices: %s", strerror(-r));
 283                 }
 284
 285                 if (need_dm_detach) {
 286                         log_info("Detaching DM devices.");
 287                         r = dm_detach_all();
 288                         if (r == 0)
 289                                 need_dm_detach = false;
 290                         else if (r > 0)
 291                                 log_warning("Not all dm devices detached, %d left.", r);
 292                         else
 293                                 log_error("Error detaching dm devices: %s", strerror(-r));
 294                 }
 295
 296                 if (need_umount || need_swapoff || need_loop_detach || need_dm_detach) {
 297                         retries--;
 298
 299                         if (retries == FINALIZE_CRITICAL_ATTEMPTS) {
 300                                 log_warning("Approaching critical level to finalize filesystem and devices, try to kill all processes.");
 301                                 rescue_send_signal(SIGTERM);
 302                                 rescue_send_signal(SIGKILL);
 303                         }
 304
 305                         if (retries > 0)
 306                                 log_info("Action still required, %d tries left.", retries);
 307                         else {
 308                                 log_error("Giving up. Actions left: Umount=%s, Swap off=%s, Loop detach=%s, dm detach=%s",
 309                                           yes_no(need_umount), yes_no(need_swapoff), yes_no(need_loop_detach), yes_no(need_dm_detach));
 310                                 break;
 311                         }
 312                 } else
 313                         break;
 314         }
 315
 316         sync();
 317
 318         if (cmd == LINUX_REBOOT_CMD_KEXEC) {
 319                 /* we cheat and exec kexec to avoid doing all its work */
 320                 pid_t pid = fork();
 321                 if (pid < 0)
 322                         log_error("Could not fork: %m. Falling back to normal reboot.");
 323                 else if (pid > 0) {
 324                         wait_for_terminate_and_warn("kexec", pid);
 325                         log_warning("kexec failed. Falling back to normal reboot.");
 326                 } else {
 327                         /* Child */
 328                         const char *args[5] = { KEXEC_BINARY_PATH, "-e", "-f", "-x", NULL };
 329                         execv(args[0], (char * const *) args);
 330                         return EXIT_FAILURE;
 331                 }
 332
 333                 cmd = RB_AUTOBOOT;
 334         }
 335
 336         reboot(cmd);
 337         log_error("Failed to invoke reboot(): %m");
 338         r = -errno;
 339
 340   error:
 341         sync();
 342         log_error("Critical error while doing system shutdown: %s", strerror(-r));
 343
 344         freeze();
 345         return EXIT_FAILURE;
 346 }