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                         log_warning("Failed: sigtimedwait did not return SIGCHLD: %m");
 144         }
 145
 146 finish:
 147         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 148
 149         return n_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;
 203         unsigned retries;
 204         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
 205         bool killed_everbody = false;
 206
 207         log_parse_environment();
 208         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
 209         log_open();
 210
 211         if (getpid() != 1) {
 212                 log_error("Not executed by init (pid 1).");
 213                 r = -EPERM;
 214                 goto error;
 215         }
 216
 217         if (argc != 2) {
 218                 log_error("Invalid number of arguments.");
 219                 r = -EINVAL;
 220                 goto error;
 221         }
 222
 223         if (streq(argv[1], "reboot"))
 224                 cmd = RB_AUTOBOOT;
 225         else if (streq(argv[1], "poweroff"))
 226                 cmd = RB_POWER_OFF;
 227         else if (streq(argv[1], "halt"))
 228                 cmd = RB_HALT_SYSTEM;
 229         else if (streq(argv[1], "kexec"))
 230                 cmd = LINUX_REBOOT_CMD_KEXEC;
 231         else {
 232                 log_error("Unknown action '%s'.", argv[1]);
 233                 r = -EINVAL;
 234                 goto error;
 235         }
 236
 237         /* lock us into memory */
 238         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
 239                 log_warning("Cannot lock process memory: %m");
 240
 241         log_info("Sending SIGTERM to processes");
 242         r = send_signal(SIGTERM);
 243         if (r < 0)
 244                 log_warning("Cannot send SIGTERM to all process: %s", strerror(r));
 245
 246         log_info("Sending SIGKILL to processes");
 247         r = send_signal(SIGKILL);
 248         if (r < 0)
 249                 log_warning("Cannot send SIGKILL to all process: %s", strerror(r));
 250
 251         /* Unmount all mountpoints, swaps, and loopback devices */
 252         for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
 253                 bool changed = false;
 254
 255                 if (need_umount) {
 256                         log_info("Unmounting filesystems.");
 257                         r = umount_all(&changed);
 258                         if (r == 0)
 259                                 need_umount = false;
 260                         else if (r > 0)
 261                                 log_warning("Not all filesystems unmounted, %d left.", r);
 262                         else
 263                                 log_error("Error unmounting filesystems: %s", strerror(-r));
 264                 }
 265
 266                 if (need_swapoff) {
 267                         log_info("Disabling swaps.");
 268                         r = swapoff_all(&changed);
 269                         if (r == 0)
 270                                 need_swapoff = false;
 271                         else if (r > 0)
 272                                 log_warning("Not all swaps are off, %d left.", r);
 273                         else
 274                                 log_error("Error turning off swaps: %s", strerror(-r));
 275                 }
 276
 277                 if (need_loop_detach) {
 278                         log_info("Detaching loop devices.");
 279                         r = loopback_detach_all(&changed);
 280                         if (r == 0)
 281                                 need_loop_detach = false;
 282                         else if (r > 0)
 283                                 log_warning("Not all loop devices detached, %d left.", r);
 284                         else
 285                                 log_error("Error detaching loop devices: %s", strerror(-r));
 286                 }
 287
 288                 if (need_dm_detach) {
 289                         log_info("Detaching DM devices.");
 290                         r = dm_detach_all(&changed);
 291                         if (r == 0)
 292                                 need_dm_detach = false;
 293                         else if (r > 0)
 294                                 log_warning("Not all dm devices detached, %d left.", r);
 295                         else
 296                                 log_error("Error detaching dm devices: %s", strerror(-r));
 297                 }
 298
 299                 if (!need_umount && !need_swapoff && !need_loop_detach && !need_dm_detach)
 300                         /* Yay, done */
 301                         break;
 302
 303                 /* If in this iteration we didn't manage to
 304                  * unmount/deactivate anything, we either kill more
 305                  * processes, or simply give up */
 306                 if (!changed) {
 307
 308                         if (killed_everbody) {
 309                                 /* Hmm, we already killed everybody,
 310                                  * let's just give up */
 311                                 log_error("Cannot finalize all filesystems and devices, giving up.");
 312                                 break;
 313                         }
 314
 315                         log_warning("Cannot finalize filesystems and devices, trying to kill remaining processes.");
 316                         rescue_send_signal(SIGTERM);
 317                         rescue_send_signal(SIGKILL);
 318                         killed_everbody = true;
 319                 }
 320
 321                 log_debug("Couldn't finalize filesystems and devices after %u retries, trying again.", retries+1);
 322         }
 323
 324         if (retries >= FINALIZE_ATTEMPTS)
 325                 log_error("Too many interations, giving up.");
 326
 327         sync();
 328
 329         if (cmd == LINUX_REBOOT_CMD_KEXEC) {
 330                 /* We cheat and exec kexec to avoid doing all its work */
 331                 pid_t pid = fork();
 332
 333                 if (pid < 0)
 334                         log_error("Could not fork: %m. Falling back to normal reboot.");
 335                 else if (pid > 0) {
 336                         wait_for_terminate_and_warn("kexec", pid);
 337                         log_warning("kexec failed. Falling back to normal reboot.");
 338                 } else {
 339                         /* Child */
 340                         const char *args[5] = { KEXEC_BINARY_PATH, "-e", "-f", "-x", NULL };
 341                         execv(args[0], (char * const *) args);
 342                         return EXIT_FAILURE;
 343                 }
 344
 345                 cmd = RB_AUTOBOOT;
 346         }
 347
 348         reboot(cmd);
 349         log_error("Failed to invoke reboot(): %m");
 350         r = -errno;
 351
 352   error:
 353         sync();
 354         log_error("Critical error while doing system shutdown: %s", strerror(-r));
 355
 356         freeze();
 357         return EXIT_FAILURE;
 358 }