udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  * Copyright (C) 2009 Canonical Ltd.
   5  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <fcntl.h>
  30 #include <time.h>
  31 #include <getopt.h>
  32 #include <dirent.h>
  33 #include <sys/select.h>
  34 #include <sys/poll.h>
  35 #include <sys/wait.h>
  36 #include <sys/stat.h>
  37 #include <sys/ioctl.h>
  38 #ifdef HAVE_INOTIFY
  39 #include <sys/inotify.h>
  40 #endif
  41
  42 #include "udev.h"
  43
  44 #define UDEVD_PRIORITY                  -4
  45 #define UDEV_PRIORITY                   -2
  46
  47 /* maximum limit of forked childs */
  48 #define UDEVD_MAX_CHILDS                256
  49
  50 static int debug;
  51
  52 static void log_fn(struct udev *udev, int priority,
  53                    const char *file, int line, const char *fn,
  54                    const char *format, va_list args)
  55 {
  56         if (debug) {
  57                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  58                 vfprintf(stderr, format, args);
  59         } else {
  60                 vsyslog(priority, format, args);
  61         }
  62 }
  63
  64 static void reap_sigchilds(void);
  65
  66 static int debug_trace;
  67 static struct udev_rules *rules;
  68 static struct udev_ctrl *udev_ctrl;
  69 static struct udev_monitor *kernel_monitor;
  70 static volatile sig_atomic_t sigchilds_waiting;
  71 static volatile sig_atomic_t udev_exit;
  72 static volatile sig_atomic_t reload_config;
  73 static volatile sig_atomic_t signal_received;
  74 static volatile pid_t settle_pid;
  75 static int run_exec_q;
  76 static int stop_exec_q;
  77 static int max_childs;
  78 static int childs;
  79 static struct udev_list_node event_list;
  80
  81 enum event_state {
  82         EVENT_QUEUED,
  83         EVENT_FINISHED,
  84         EVENT_FAILED,
  85 };
  86
  87 static struct udev_event *node_to_event(struct udev_list_node *node)
  88 {
  89         char *event;
  90
  91         event = (char *)node;
  92         event -= offsetof(struct udev_event, node);
  93         return (struct udev_event *)event;
  94 }
  95
  96 static void export_event_state(struct udev_event *event, enum event_state state)
  97 {
  98         char filename[UTIL_PATH_SIZE];
  99         char filename_failed[UTIL_PATH_SIZE];
 100         char *s;
 101         size_t l;
 102
 103         /* location of queue file */
 104         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu",
 105                  udev_get_dev_path(event->udev), udev_device_get_seqnum(event->dev));
 106
 107         /* location of failed file */
 108         s = filename_failed;
 109         l = util_strpcpyl(&s, sizeof(filename_failed), udev_get_dev_path(event->udev), "/.udev/failed/", NULL);
 110         util_path_encode(udev_device_get_devpath(event->dev), s, l);
 111
 112         switch (state) {
 113         case EVENT_QUEUED:
 114                 if(unlink(filename_failed) == 0)
 115                         util_delete_path(event->udev, filename_failed);
 116                 util_create_path(event->udev, filename);
 117                 udev_selinux_setfscreatecon(event->udev, filename, S_IFLNK);
 118                 symlink(udev_device_get_devpath(event->dev), filename);
 119                 udev_selinux_resetfscreatecon(event->udev);
 120                 break;
 121         case EVENT_FINISHED:
 122                 if (udev_device_get_devpath_old(event->dev) != NULL) {
 123                         /* "move" event - rename failed file to current name, do not delete failed */
 124                         char filename_failed_old[UTIL_PATH_SIZE];
 125
 126                         s = filename_failed_old;
 127                         l = util_strpcpyl(&s, sizeof(filename_failed_old), udev_get_dev_path(event->udev), "/.udev/failed/", NULL);
 128                         util_path_encode(udev_device_get_devpath_old(event->dev), s, l);
 129                         if (rename(filename_failed_old, filename_failed) == 0)
 130                                 info(event->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 131                                      udev_device_get_devpath_old(event->dev), udev_device_get_devpath(event->dev));
 132                 } else {
 133                         if (unlink(filename_failed) == 0)
 134                                 util_delete_path(event->udev, filename_failed);
 135                 }
 136
 137                 unlink(filename);
 138
 139                 /* clean up possibly empty queue directory */
 140                 if (udev_list_is_empty(&event_list))
 141                         util_delete_path(event->udev, filename);
 142                 break;
 143         case EVENT_FAILED:
 144                 /* move failed event to the failed directory */
 145                 util_create_path(event->udev, filename_failed);
 146                 rename(filename, filename_failed);
 147
 148                 /* clean up possibly empty queue directory */
 149                 if (udev_list_is_empty(&event_list))
 150                         util_delete_path(event->udev, filename);
 151                 break;
 152         }
 153
 154         return;
 155 }
 156
 157 static void event_queue_delete(struct udev_event *event)
 158 {
 159         udev_list_node_remove(&event->node);
 160
 161         /* mark as failed, if "add" event returns non-zero */
 162         if (event->exitstatus && strcmp(udev_device_get_action(event->dev), "add") == 0)
 163                 export_event_state(event, EVENT_FAILED);
 164         else
 165                 export_event_state(event, EVENT_FINISHED);
 166
 167         udev_device_unref(event->dev);
 168         udev_event_unref(event);
 169 }
 170
 171 static void event_sig_handler(int signum)
 172 {
 173         if (signum == SIGALRM)
 174                 _exit(1);
 175 }
 176
 177 static void event_fork(struct udev_event *event)
 178 {
 179         pid_t pid;
 180         struct sigaction act;
 181         int err;
 182
 183         if (debug_trace) {
 184                 event->trace = 1;
 185                 fprintf(stderr, "fork %s (%llu)\n",
 186                        udev_device_get_syspath(event->dev),
 187                        udev_device_get_seqnum(event->dev));
 188         }
 189
 190         pid = fork();
 191         switch (pid) {
 192         case 0:
 193                 /* child */
 194                 udev_ctrl_unref(udev_ctrl);
 195                 logging_close();
 196                 logging_init("udevd-event");
 197                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 198
 199                 /* set signal handlers */
 200                 memset(&act, 0x00, sizeof(act));
 201                 act.sa_handler = event_sig_handler;
 202                 sigemptyset (&act.sa_mask);
 203                 act.sa_flags = 0;
 204                 sigaction(SIGALRM, &act, NULL);
 205
 206                 /* reset to default */
 207                 act.sa_handler = SIG_DFL;
 208                 sigaction(SIGINT, &act, NULL);
 209                 sigaction(SIGTERM, &act, NULL);
 210                 sigaction(SIGCHLD, &act, NULL);
 211                 sigaction(SIGHUP, &act, NULL);
 212
 213                 /* set timeout to prevent hanging processes */
 214                 alarm(UDEV_EVENT_TIMEOUT);
 215
 216                 /* apply rules, create node, symlinks */
 217                 err = udev_event_execute_rules(event, rules);
 218
 219                 /* rules may change/disable the timeout */
 220                 if (udev_device_get_event_timeout(event->dev) >= 0)
 221                         alarm(udev_device_get_event_timeout(event->dev));
 222
 223                 /* execute RUN= */
 224                 if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 225                         udev_event_execute_run(event);
 226
 227                 /* apply/restore inotify watch */
 228                 if (err == 0 && event->inotify_watch) {
 229                         udev_watch_begin(event->udev, event->dev);
 230                         udev_device_update_db(event->dev);
 231                 }
 232
 233                 /* send processed event back to the kernel netlink socket */
 234                 udev_monitor_send_device(kernel_monitor, event->dev);
 235
 236                 info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 237                 logging_close();
 238                 if (err != 0)
 239                         exit(1);
 240                 exit(0);
 241         case -1:
 242                 err(event->udev, "fork of child failed: %m\n");
 243                 event_queue_delete(event);
 244                 break;
 245         default:
 246                 /* get SIGCHLD in main loop */
 247                 info(event->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 248                      udev_device_get_seqnum(event->dev),
 249                      pid,
 250                      udev_device_get_action(event->dev),
 251                      udev_device_get_subsystem(event->dev),
 252                      time(NULL) - event->queue_time);
 253                 event->pid = pid;
 254                 childs++;
 255         }
 256 }
 257
 258 static void event_queue_insert(struct udev_event *event)
 259 {
 260         char filename[UTIL_PATH_SIZE];
 261         int fd;
 262
 263         event->queue_time = time(NULL);
 264
 265         export_event_state(event, EVENT_QUEUED);
 266         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(event->dev),
 267              udev_device_get_action(event->dev), udev_device_get_subsystem(event->dev));
 268
 269         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(event->udev), "/.udev/uevent_seqnum", NULL);
 270         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 271         if (fd >= 0) {
 272                 char str[32];
 273                 int len;
 274
 275                 len = sprintf(str, "%llu\n", udev_device_get_seqnum(event->dev));
 276                 write(fd, str, len);
 277                 close(fd);
 278         }
 279
 280
 281         udev_list_node_append(&event->node, &event_list);
 282         run_exec_q = 1;
 283
 284         /* run all events with a timeout set immediately */
 285         if (udev_device_get_timeout(event->dev) > 0) {
 286                 event_fork(event);
 287                 return;
 288         }
 289 }
 290
 291 static int mem_size_mb(void)
 292 {
 293         FILE *f;
 294         char buf[4096];
 295         long int memsize = -1;
 296
 297         f = fopen("/proc/meminfo", "r");
 298         if (f == NULL)
 299                 return -1;
 300
 301         while (fgets(buf, sizeof(buf), f) != NULL) {
 302                 long int value;
 303
 304                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 305                         memsize = value / 1024;
 306                         break;
 307                 }
 308         }
 309
 310         fclose(f);
 311         return memsize;
 312 }
 313
 314 static int compare_devpath(const char *running, const char *waiting)
 315 {
 316         int i = 0;
 317
 318         while (running[i] != '\0' && running[i] == waiting[i])
 319                 i++;
 320
 321         /* identical device event found */
 322         if (running[i] == '\0' && waiting[i] == '\0')
 323                 return 1;
 324
 325         /* parent device event found */
 326         if (running[i] == '\0' && waiting[i] == '/')
 327                 return 2;
 328
 329         /* child device event found */
 330         if (running[i] == '/' && waiting[i] == '\0')
 331                 return 3;
 332
 333         /* no matching event */
 334         return 0;
 335 }
 336
 337 /* lookup event for identical, parent, child device */
 338 static int devpath_busy(struct udev_event *event)
 339 {
 340         struct udev_list_node *loop;
 341
 342         if (event->delaying_seqnum > 0) {
 343         }
 344         /* check if queue contains events we depend on */
 345         udev_list_node_foreach(loop, &event_list) {
 346                 struct udev_event *loop_event = node_to_event(loop);
 347
 348                 /* we already found a later event, earlier can not block us, no need to check again */
 349                 if (udev_device_get_seqnum(loop_event->dev) < event->delaying_seqnum)
 350                         continue;
 351
 352                 /* event we checked earlier still exists, no need to check again */
 353                 if (udev_device_get_seqnum(loop_event->dev) == event->delaying_seqnum)
 354                         return 2;
 355
 356                 /* found ourself, no later event can block us */
 357                 if (udev_device_get_seqnum(loop_event->dev) >= udev_device_get_seqnum(event->dev))
 358                         break;
 359
 360                 /* check our old name */
 361                 if (udev_device_get_devpath_old(event->dev) != NULL)
 362                         if (strcmp(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath_old(event->dev)) == 0) {
 363                                 event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 364                                 return 3;
 365                         }
 366
 367                 /* check identical, parent, or child device event */
 368                 if (compare_devpath(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath(event->dev)) != 0) {
 369                         dbg(event->udev, "%llu, device event still pending %llu (%s)\n",
 370                             udev_device_get_seqnum(event->dev),
 371                             udev_device_get_seqnum(loop_event->dev),
 372                             udev_device_get_devpath(loop_event->dev));
 373                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 374                         return 4;
 375                 }
 376
 377                 /* check for our major:minor number */
 378                 if (major(udev_device_get_devnum(event->dev)) > 0 &&
 379                     udev_device_get_devnum(loop_event->dev) == udev_device_get_devnum(event->dev) &&
 380                     strcmp(udev_device_get_subsystem(event->dev), udev_device_get_subsystem(loop_event->dev)) == 0) {
 381                         dbg(event->udev, "%llu, device event still pending %llu (%d:%d)\n",
 382                             udev_device_get_seqnum(event->dev),
 383                             udev_device_get_seqnum(loop_event->dev),
 384                             major(udev_device_get_devnum(loop_event->dev)), minor(udev_device_get_devnum(loop_event->dev)));
 385                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 386                         return 5;
 387                 }
 388         }
 389         return 0;
 390 }
 391
 392 /* serializes events for the identical and parent and child devices */
 393 static void event_queue_manager(struct udev *udev)
 394 {
 395         struct udev_list_node *loop;
 396         struct udev_list_node *tmp;
 397
 398 start_over:
 399         if (udev_list_is_empty(&event_list)) {
 400                 if (childs > 0) {
 401                         err(udev, "event list empty, but childs count is %i", childs);
 402                         childs = 0;
 403                 }
 404                 return;
 405         }
 406
 407         udev_list_node_foreach_safe(loop, tmp, &event_list) {
 408                 struct udev_event *loop_event = node_to_event(loop);
 409
 410                 if (childs >= max_childs) {
 411                         info(udev, "maximum number (%i) of childs reached\n", childs);
 412                         break;
 413                 }
 414
 415                 if (loop_event->pid != 0)
 416                         continue;
 417
 418                 /* do not start event if parent or child event is still running */
 419                 if (devpath_busy(loop_event) != 0) {
 420                         dbg(udev, "delay seq %llu (%s)\n",
 421                             udev_device_get_seqnum(loop_event->dev),
 422                             udev_device_get_devpath(loop_event->dev));
 423                         continue;
 424                 }
 425
 426                 event_fork(loop_event);
 427                 dbg(udev, "moved seq %llu to running list\n", udev_device_get_seqnum(loop_event->dev));
 428
 429                 /* retry if events finished in the meantime */
 430                 if (sigchilds_waiting) {
 431                         sigchilds_waiting = 0;
 432                         reap_sigchilds();
 433                         goto start_over;
 434                 }
 435         }
 436 }
 437
 438 /* receive the udevd message from userspace */
 439 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 440 {
 441         struct udev *udev = udev_ctrl_get_udev(uctrl);
 442         struct udev_ctrl_msg *ctrl_msg;
 443         const char *str;
 444         int i;
 445
 446         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 447         if (ctrl_msg == NULL)
 448                 return;
 449
 450         i = udev_ctrl_get_set_log_level(ctrl_msg);
 451         if (i >= 0) {
 452                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 453                 udev_set_log_priority(udev, i);
 454         }
 455
 456         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 457                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 458                 stop_exec_q = 1;
 459         }
 460
 461         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 462                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 463                 stop_exec_q = 0;
 464                 event_queue_manager(udev);
 465         }
 466
 467         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 468                 info(udev, "udevd message (RELOAD_RULES) received\n");
 469                 reload_config = 1;
 470         }
 471
 472         str = udev_ctrl_get_set_env(ctrl_msg);
 473         if (str != NULL) {
 474                 char *key;
 475
 476                 key = strdup(str);
 477                 if (key != NULL) {
 478                         char *val;
 479
 480                         val = strchr(key, '=');
 481                         if (val != NULL) {
 482                                 val[0] = '\0';
 483                                 val = &val[1];
 484                                 if (val[0] == '\0') {
 485                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 486                                         udev_add_property(udev, key, NULL);
 487                                 } else {
 488                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 489                                         udev_add_property(udev, key, val);
 490                                 }
 491                         } else {
 492                                 err(udev, "wrong key format '%s'\n", key);
 493                         }
 494                         free(key);
 495                 }
 496         }
 497
 498         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 499         if (i >= 0) {
 500                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 501                 max_childs = i;
 502         }
 503
 504         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 505         if (settle_pid > 0) {
 506                 info(udev, "udevd message (SETTLE) received\n");
 507         }
 508         udev_ctrl_msg_unref(ctrl_msg);
 509 }
 510
 511 /* read inotify messages */
 512 static int handle_inotify(struct udev *udev)
 513 {
 514         int nbytes, pos;
 515         char *buf;
 516         struct inotify_event *ev;
 517
 518         if ((ioctl(inotify_fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 519                 return 0;
 520
 521         buf = malloc(nbytes);
 522         if (buf == NULL) {
 523                 err(udev, "error getting buffer for inotify, disable watching\n");
 524                 close(inotify_fd);
 525                 inotify_fd = -1;
 526                 return 0;
 527         }
 528
 529         read(inotify_fd, buf, nbytes);
 530
 531         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 532                 struct udev_device *dev;
 533
 534                 ev = (struct inotify_event *)(buf + pos);
 535                 if (ev->len) {
 536                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 537                         reload_config = 1;
 538                         continue;
 539                 }
 540
 541                 dev = udev_watch_lookup(udev, ev->wd);
 542                 if (dev != NULL) {
 543                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 544                         if (ev->mask & IN_CLOSE_WRITE) {
 545                                 char filename[UTIL_PATH_SIZE];
 546                                 int fd;
 547
 548                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 549                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 550                                 fd = open(filename, O_WRONLY);
 551                                 if (fd < 0 || write(fd, "change", 6) < 0)
 552                                         info(udev, "error writing uevent: %m\n");
 553                                 close(fd);
 554                         }
 555                         if (ev->mask & IN_IGNORED)
 556                                 udev_watch_end(udev, dev);
 557
 558                         udev_device_unref(dev);
 559                 }
 560
 561         }
 562
 563         free (buf);
 564         return 0;
 565 }
 566
 567 static void sig_handler(int signum)
 568 {
 569         switch (signum) {
 570                 case SIGINT:
 571                 case SIGTERM:
 572                         udev_exit = 1;
 573                         break;
 574                 case SIGCHLD:
 575                         /* set flag, then write to pipe if needed */
 576                         sigchilds_waiting = 1;
 577                         break;
 578                 case SIGHUP:
 579                         reload_config = 1;
 580                         break;
 581         }
 582
 583         signal_received = 1;
 584 }
 585
 586 static void udev_done(int pid, int exitstatus)
 587 {
 588         struct udev_list_node *loop;
 589
 590         /* find event associated with pid and delete it */
 591         udev_list_node_foreach(loop, &event_list) {
 592                 struct udev_event *loop_event = node_to_event(loop);
 593
 594                 if (loop_event->pid == pid) {
 595                         info(loop_event->udev, "seq %llu cleanup, pid [%d], status %i, %ld seconds old\n",
 596                              udev_device_get_seqnum(loop_event->dev), loop_event->pid,
 597                              exitstatus, time(NULL) - loop_event->queue_time);
 598                         loop_event->exitstatus = exitstatus;
 599                         if (debug_trace)
 600                                 fprintf(stderr, "exit %s (%llu)\n",
 601                                        udev_device_get_syspath(loop_event->dev),
 602                                        udev_device_get_seqnum(loop_event->dev));
 603                         event_queue_delete(loop_event);
 604                         childs--;
 605
 606                         /* there may be dependent events waiting */
 607                         run_exec_q = 1;
 608                         return;
 609                 }
 610         }
 611 }
 612
 613 static void reap_sigchilds(void)
 614 {
 615         pid_t pid;
 616         int status;
 617
 618         while (1) {
 619                 pid = waitpid(-1, &status, WNOHANG);
 620                 if (pid <= 0)
 621                         break;
 622                 if (WIFEXITED(status))
 623                         status = WEXITSTATUS(status);
 624                 else if (WIFSIGNALED(status))
 625                         status = WTERMSIG(status) + 128;
 626                 else
 627                         status = 0;
 628                 udev_done(pid, status);
 629         }
 630 }
 631
 632 static void cleanup_queue_dir(struct udev *udev)
 633 {
 634         char dirname[UTIL_PATH_SIZE];
 635         char filename[UTIL_PATH_SIZE];
 636         DIR *dir;
 637
 638         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/uevent_seqnum", NULL);
 639         unlink(filename);
 640
 641         util_strscpyl(dirname, sizeof(dirname), udev_get_dev_path(udev), "/.udev/queue", NULL);
 642         dir = opendir(dirname);
 643         if (dir != NULL) {
 644                 while (1) {
 645                         struct dirent *dent;
 646
 647                         dent = readdir(dir);
 648                         if (dent == NULL || dent->d_name[0] == '\0')
 649                                 break;
 650                         if (dent->d_name[0] == '.')
 651                                 continue;
 652                         unlinkat(dirfd(dir), dent->d_name, 0);
 653                 }
 654                 closedir(dir);
 655                 rmdir(dirname);
 656         }
 657 }
 658
 659 static void export_initial_seqnum(struct udev *udev)
 660 {
 661         char filename[UTIL_PATH_SIZE];
 662         int fd;
 663         char seqnum[32];
 664         ssize_t len = 0;
 665
 666         util_strscpyl(filename, sizeof(filename), udev_get_sys_path(udev), "/kernel/uevent_seqnum", NULL);
 667         fd = open(filename, O_RDONLY);
 668         if (fd >= 0) {
 669                 len = read(fd, seqnum, sizeof(seqnum)-1);
 670                 close(fd);
 671         }
 672         if (len <= 0) {
 673                 strcpy(seqnum, "0\n");
 674                 len = 3;
 675         }
 676         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/uevent_seqnum", NULL);
 677         util_create_path(udev, filename);
 678         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 679         if (fd >= 0) {
 680                 write(fd, seqnum, len);
 681                 close(fd);
 682         }
 683 }
 684
 685 static void startup_log(struct udev *udev)
 686 {
 687         FILE *f;
 688         char path[UTIL_PATH_SIZE];
 689         struct stat statbuf;
 690
 691         f = fopen("/dev/kmsg", "w");
 692         if (f != NULL)
 693                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 694
 695         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 696         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 697                 const char *depr_str =
 698                         "udev: missing sysfs features; please update the kernel "
 699                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 700                         "udev may fail to work correctly";
 701
 702                 if (f != NULL)
 703                         fprintf(f, "<3>%s\n", depr_str);
 704                 err(udev, "%s\n", depr_str);
 705                 sleep(3);
 706         }
 707
 708         if (f != NULL)
 709                 fclose(f);
 710 }
 711
 712 int main(int argc, char *argv[])
 713 {
 714         struct udev *udev;
 715         int fd;
 716         struct sigaction act;
 717         const char *value;
 718         int daemonize = 0;
 719         int resolve_names = 1;
 720         static const struct option options[] = {
 721                 { "daemon", no_argument, NULL, 'd' },
 722                 { "debug-trace", no_argument, NULL, 't' },
 723                 { "debug", no_argument, NULL, 'D' },
 724                 { "help", no_argument, NULL, 'h' },
 725                 { "version", no_argument, NULL, 'V' },
 726                 { "resolve-names", required_argument, NULL, 'N' },
 727                 {}
 728         };
 729         int rc = 1;
 730
 731         udev = udev_new();
 732         if (udev == NULL)
 733                 goto exit;
 734
 735         logging_init("udevd");
 736         udev_set_log_fn(udev, log_fn);
 737         info(udev, "version %s\n", VERSION);
 738         udev_selinux_init(udev);
 739
 740         while (1) {
 741                 int option;
 742
 743                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 744                 if (option == -1)
 745                         break;
 746
 747                 switch (option) {
 748                 case 'd':
 749                         daemonize = 1;
 750                         break;
 751                 case 't':
 752                         debug_trace = 1;
 753                         break;
 754                 case 'D':
 755                         debug = 1;
 756                         if (udev_get_log_priority(udev) < LOG_INFO)
 757                                 udev_set_log_priority(udev, LOG_INFO);
 758                         break;
 759                 case 'N':
 760                         if (strcmp (optarg, "early") == 0) {
 761                                 resolve_names = 1;
 762                         } else if (strcmp (optarg, "late") == 0) {
 763                                 resolve_names = 0;
 764                         } else if (strcmp (optarg, "never") == 0) {
 765                                 resolve_names = -1;
 766                         } else {
 767                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 768                                 err(udev, "resolve-names must be early, late or never\n");
 769                                 goto exit;
 770                         }
 771                         break;
 772                 case 'h':
 773                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 774                                "[--resolve-names=early|late|never] [--version]\n");
 775                         goto exit;
 776                 case 'V':
 777                         printf("%s\n", VERSION);
 778                         goto exit;
 779                 default:
 780                         goto exit;
 781                 }
 782         }
 783
 784         if (getuid() != 0) {
 785                 fprintf(stderr, "root privileges required\n");
 786                 err(udev, "root privileges required\n");
 787                 goto exit;
 788         }
 789
 790         /* make sure std{in,out,err} fd's are in a sane state */
 791         fd = open("/dev/null", O_RDWR);
 792         if (fd < 0) {
 793                 fprintf(stderr, "cannot open /dev/null\n");
 794                 err(udev, "cannot open /dev/null\n");
 795         }
 796         if (write(STDOUT_FILENO, 0, 0) < 0)
 797                 dup2(fd, STDOUT_FILENO);
 798         if (write(STDERR_FILENO, 0, 0) < 0)
 799                 dup2(fd, STDERR_FILENO);
 800
 801         /* init control socket, bind() ensures, that only one udevd instance is running */
 802         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 803         if (udev_ctrl == NULL) {
 804                 fprintf(stderr, "error initializing control socket");
 805                 err(udev, "error initializing udevd socket");
 806                 rc = 1;
 807                 goto exit;
 808         }
 809
 810         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 811                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 812                 err(udev, "error binding control socket, seems udevd is already running\n");
 813                 rc = 1;
 814                 goto exit;
 815         }
 816
 817         kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 818         if (kernel_monitor == NULL || udev_monitor_enable_receiving(kernel_monitor) < 0) {
 819                 fprintf(stderr, "error initializing netlink socket\n");
 820                 err(udev, "error initializing netlink socket\n");
 821                 rc = 3;
 822                 goto exit;
 823         }
 824         udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 825
 826         rules = udev_rules_new(udev, resolve_names);
 827         if (rules == NULL) {
 828                 err(udev, "error reading rules\n");
 829                 goto exit;
 830         }
 831         udev_list_init(&event_list);
 832         cleanup_queue_dir(udev);
 833         export_initial_seqnum(udev);
 834
 835         if (daemonize) {
 836                 pid_t pid;
 837
 838                 pid = fork();
 839                 switch (pid) {
 840                 case 0:
 841                         dbg(udev, "daemonized fork running\n");
 842                         break;
 843                 case -1:
 844                         err(udev, "fork of daemon failed: %m\n");
 845                         rc = 4;
 846                         goto exit;
 847                 default:
 848                         dbg(udev, "child [%u] running, parent exits\n", pid);
 849                         rc = 0;
 850                         goto exit;
 851                 }
 852         }
 853
 854         /* redirect std{out,err} */
 855         if (!debug && !debug_trace) {
 856                 dup2(fd, STDIN_FILENO);
 857                 dup2(fd, STDOUT_FILENO);
 858                 dup2(fd, STDERR_FILENO);
 859         }
 860         if (fd > STDERR_FILENO)
 861                 close(fd);
 862
 863         /* set scheduling priority for the daemon */
 864         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 865
 866         chdir("/");
 867         umask(022);
 868         setsid();
 869
 870         /* OOM_DISABLE == -17 */
 871         fd = open("/proc/self/oom_adj", O_RDWR);
 872         if (fd < 0)
 873                 err(udev, "error disabling OOM: %m\n");
 874         else {
 875                 write(fd, "-17", 3);
 876                 close(fd);
 877         }
 878
 879         startup_log(udev);
 880
 881         /* set signal handlers */
 882         memset(&act, 0x00, sizeof(struct sigaction));
 883         act.sa_handler = sig_handler;
 884         sigemptyset(&act.sa_mask);
 885         act.sa_flags = SA_RESTART;
 886         sigaction(SIGINT, &act, NULL);
 887         sigaction(SIGTERM, &act, NULL);
 888         sigaction(SIGCHLD, &act, NULL);
 889         sigaction(SIGHUP, &act, NULL);
 890
 891         /* watch rules directory */
 892         udev_watch_init(udev);
 893         if (inotify_fd >= 0) {
 894                 if (udev_get_rules_path(udev) != NULL) {
 895                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 896                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 897                 } else {
 898                         char filename[UTIL_PATH_SIZE];
 899
 900                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 901                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 902                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 903                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 904
 905                         /* watch dynamic rules directory */
 906                         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 907                         inotify_add_watch(inotify_fd, filename,
 908                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 909                 }
 910
 911                 udev_watch_restore(udev);
 912         }
 913
 914         /* in trace mode run one event after the other */
 915         if (debug_trace) {
 916                 max_childs = 1;
 917         } else {
 918                 int memsize = mem_size_mb();
 919                 if (memsize > 0)
 920                         max_childs = 128 + (memsize / 4);
 921                 else
 922                         max_childs = UDEVD_MAX_CHILDS;
 923         }
 924         /* possibly overwrite maximum limit of executed events */
 925         value = getenv("UDEVD_MAX_CHILDS");
 926         if (value)
 927                 max_childs = strtoul(value, NULL, 10);
 928         info(udev, "initialize max_childs to %u\n", max_childs);
 929
 930         while (!udev_exit) {
 931                 sigset_t blocked_mask, orig_mask;
 932                 struct pollfd pfd[4];
 933                 struct pollfd *ctrl_poll, *monitor_poll, *inotify_poll = NULL;
 934                 int nfds = 0;
 935                 int fdcount;
 936
 937                 sigfillset(&blocked_mask);
 938                 sigprocmask(SIG_SETMASK, &blocked_mask, &orig_mask);
 939                 if (signal_received) {
 940                         sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 941                         goto handle_signals;
 942                 }
 943
 944                 ctrl_poll = &pfd[nfds++];
 945                 ctrl_poll->fd = udev_ctrl_get_fd(udev_ctrl);
 946                 ctrl_poll->events = POLLIN;
 947
 948                 monitor_poll = &pfd[nfds++];
 949                 monitor_poll->fd = udev_monitor_get_fd(kernel_monitor);
 950                 monitor_poll->events = POLLIN;
 951
 952                 if (inotify_fd >= 0) {
 953                         inotify_poll = &pfd[nfds++];
 954                         inotify_poll->fd = inotify_fd;
 955                         inotify_poll->events = POLLIN;
 956                 }
 957
 958                 fdcount = ppoll(pfd, nfds, NULL, &orig_mask);
 959                 sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 960                 if (fdcount < 0) {
 961                         if (errno == EINTR)
 962                                 goto handle_signals;
 963                         err(udev, "error in select: %m\n");
 964                         continue;
 965                 }
 966
 967                 /* get control message */
 968                 if (ctrl_poll->revents & POLLIN)
 969                         handle_ctrl_msg(udev_ctrl);
 970
 971                 /* get kernel uevent */
 972                 if (monitor_poll->revents & POLLIN) {
 973                         struct udev_device *dev;
 974
 975                         dev = udev_monitor_receive_device(kernel_monitor);
 976                         if (dev != NULL) {
 977                                 struct udev_event *event;
 978
 979                                 event = udev_event_new(dev);
 980                                 if (event != NULL)
 981                                         event_queue_insert(event);
 982                                 else
 983                                         udev_device_unref(dev);
 984                         }
 985                 }
 986
 987                 /* rules directory inotify watch */
 988                 if (inotify_poll && (inotify_poll->revents & POLLIN))
 989                         handle_inotify(udev);
 990
 991 handle_signals:
 992                 signal_received = 0;
 993
 994                 /* rules changed, set by inotify or a HUP signal */
 995                 if (reload_config) {
 996                         struct udev_rules *rules_new;
 997
 998                         reload_config = 0;
 999                         rules_new = udev_rules_new(udev, resolve_names);
1000                         if (rules_new != NULL) {
1001                                 udev_rules_unref(rules);
1002                                 rules = rules_new;
1003                         }
1004                 }
1005
1006                 if (sigchilds_waiting) {
1007                         sigchilds_waiting = 0;
1008                         reap_sigchilds();
1009                 }
1010
1011                 if (run_exec_q) {
1012                         run_exec_q = 0;
1013                         if (!stop_exec_q)
1014                                 event_queue_manager(udev);
1015                 }
1016
1017                 if (settle_pid > 0) {
1018                         kill(settle_pid, SIGUSR1);
1019                         settle_pid = 0;
1020                 }
1021         }
1022         cleanup_queue_dir(udev);
1023         rc = 0;
1024 exit:
1025         udev_rules_unref(rules);
1026         udev_ctrl_unref(udev_ctrl);
1027         if (inotify_fd >= 0)
1028                 close(inotify_fd);
1029         udev_monitor_unref(kernel_monitor);
1030         udev_selinux_exit(udev);
1031         udev_unref(udev);
1032         logging_close();
1033         return rc;
1034 }