udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2009 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 <stdbool.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <fcntl.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <dirent.h>
  34 #include <sys/prctl.h>
  35 #include <sys/socket.h>
  36 #include <sys/signalfd.h>
  37 #include <sys/select.h>
  38 #include <sys/poll.h>
  39 #include <sys/wait.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <sys/inotify.h>
  43
  44 #include "udev.h"
  45
  46 #define UDEVD_PRIORITY                  -4
  47 #define UDEV_PRIORITY                   -2
  48
  49 static bool debug;
  50
  51 static void log_fn(struct udev *udev, int priority,
  52                    const char *file, int line, const char *fn,
  53                    const char *format, va_list args)
  54 {
  55         if (debug) {
  56                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  57                 vfprintf(stderr, format, args);
  58         } else {
  59                 vsyslog(priority, format, args);
  60         }
  61 }
  62
  63 static bool debug_trace;
  64 static struct udev_rules *rules;
  65 static struct udev_queue_export *udev_queue_export;
  66 static struct udev_ctrl *udev_ctrl;
  67 static struct udev_monitor *monitor;
  68 static int worker_watch[2];
  69 static pid_t settle_pid;
  70 static bool stop_exec_queue;
  71 static bool reload_config;
  72 static int max_childs;
  73 static int childs;
  74 static struct udev_list_node event_list;
  75 static struct udev_list_node worker_list;
  76 static bool udev_exit;
  77 static volatile sig_atomic_t worker_exit;
  78
  79 enum poll_fd {
  80         FD_CONTROL,
  81         FD_NETLINK,
  82         FD_INOTIFY,
  83         FD_SIGNAL,
  84         FD_WORKER,
  85 };
  86
  87 static struct pollfd pfd[] = {
  88         [FD_NETLINK] = { .events = POLLIN },
  89         [FD_WORKER] =  { .events = POLLIN },
  90         [FD_SIGNAL] =  { .events = POLLIN },
  91         [FD_INOTIFY] = { .events = POLLIN },
  92         [FD_CONTROL] = { .events = POLLIN },
  93 };
  94
  95 enum event_state {
  96         EVENT_UNDEF,
  97         EVENT_QUEUED,
  98         EVENT_RUNNING,
  99 };
 100
 101 struct event {
 102         struct udev_list_node node;
 103         struct udev *udev;
 104         struct udev_device *dev;
 105         enum event_state state;
 106         int exitcode;
 107         unsigned long long int delaying_seqnum;
 108         unsigned long long int seqnum;
 109         const char *devpath;
 110         size_t devpath_len;
 111         const char *devpath_old;
 112 };
 113
 114 static struct event *node_to_event(struct udev_list_node *node)
 115 {
 116         char *event;
 117
 118         event = (char *)node;
 119         event -= offsetof(struct event, node);
 120         return (struct event *)event;
 121 }
 122
 123 enum worker_state {
 124         WORKER_UNDEF,
 125         WORKER_RUNNING,
 126         WORKER_IDLE,
 127         WORKER_KILLED,
 128 };
 129
 130 struct worker {
 131         struct udev_list_node node;
 132         struct udev *udev;
 133         int refcount;
 134         pid_t pid;
 135         struct udev_monitor *monitor;
 136         enum worker_state state;
 137         struct event *event;
 138 };
 139
 140 /* passed from worker to main process */
 141 struct worker_message {
 142         pid_t pid;
 143         int exitcode;
 144 };
 145
 146 static struct worker *node_to_worker(struct udev_list_node *node)
 147 {
 148         char *worker;
 149
 150         worker = (char *)node;
 151         worker -= offsetof(struct worker, node);
 152         return (struct worker *)worker;
 153 }
 154
 155 static void event_queue_delete(struct event *event)
 156 {
 157         udev_list_node_remove(&event->node);
 158
 159         /* mark as failed, if "add" event returns non-zero */
 160         if (event->exitcode && strcmp(udev_device_get_action(event->dev), "add") == 0)
 161                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 162         else
 163                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 164
 165         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 166         udev_device_unref(event->dev);
 167         free(event);
 168 }
 169
 170 static void event_sig_handler(int signum)
 171 {
 172         switch (signum) {
 173         case SIGALRM:
 174                 _exit(1);
 175                 break;
 176         case SIGTERM:
 177                 worker_exit = true;
 178                 break;
 179         }
 180 }
 181
 182 static struct worker *worker_ref(struct worker *worker)
 183 {
 184         worker->refcount++;
 185         return worker;
 186 }
 187
 188 static void worker_unref(struct worker *worker)
 189 {
 190         worker->refcount--;
 191         if (worker->refcount > 0)
 192                 return;
 193
 194         udev_list_node_remove(&worker->node);
 195         udev_monitor_unref(worker->monitor);
 196         childs--;
 197         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 198         free(worker);
 199 }
 200
 201 static void worker_new(struct event *event)
 202 {
 203         struct worker *worker;
 204         struct udev_monitor *worker_monitor;
 205         pid_t pid;
 206         struct sigaction act;
 207
 208         /* listen for new events */
 209         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 210         if (worker_monitor == NULL)
 211                 return;
 212         /* allow the main daemon netlink address to send devices to the worker */
 213         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 214         udev_monitor_enable_receiving(worker_monitor);
 215         util_set_fd_cloexec(udev_monitor_get_fd(worker_monitor));
 216
 217         worker = calloc(1, sizeof(struct worker));
 218         if (worker == NULL)
 219                 return;
 220         /* worker + event reference */
 221         worker->refcount = 2;
 222         worker->udev = event->udev;
 223
 224         pid = fork();
 225         switch (pid) {
 226         case 0: {
 227                 sigset_t sigmask;
 228                 struct udev_device *dev;
 229                 struct pollfd pmon = {
 230                         .fd = udev_monitor_get_fd(worker_monitor),
 231                         .events = POLLIN,
 232                 };
 233
 234                 udev_queue_export_unref(udev_queue_export);
 235                 udev_monitor_unref(monitor);
 236                 udev_ctrl_unref(udev_ctrl);
 237                 close(pfd[FD_SIGNAL].fd);
 238                 close(worker_watch[READ_END]);
 239                 udev_log_close();
 240                 udev_log_init("udevd-work");
 241                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 242
 243                 /* set signal handlers */
 244                 memset(&act, 0x00, sizeof(act));
 245                 act.sa_handler = event_sig_handler;
 246                 sigemptyset (&act.sa_mask);
 247                 act.sa_flags = 0;
 248                 sigaction(SIGTERM, &act, NULL);
 249                 sigaction(SIGALRM, &act, NULL);
 250
 251                 /* unblock SIGALRM */
 252                 sigfillset(&sigmask);
 253                 sigdelset(&sigmask, SIGALRM);
 254                 sigprocmask(SIG_SETMASK, &sigmask, NULL);
 255                 /* SIGTERM is unblocked in ppoll() */
 256                 sigdelset(&sigmask, SIGTERM);
 257
 258                 /* request TERM signal if parent exits */
 259                 prctl(PR_SET_PDEATHSIG, SIGTERM);
 260
 261                 /* initial device */
 262                 dev = event->dev;
 263
 264                 do {
 265                         struct udev_event *udev_event;
 266                         struct worker_message msg;
 267                         int err;
 268
 269                         udev_event = udev_event_new(dev);
 270                         if (udev_event == NULL)
 271                                 _exit(3);
 272
 273                         /* set timeout to prevent hanging processes */
 274                         alarm(UDEV_EVENT_TIMEOUT);
 275
 276                         /* apply rules, create node, symlinks */
 277                         err = udev_event_execute_rules(udev_event, rules);
 278
 279                         /* rules may change/disable the timeout */
 280                         if (udev_device_get_event_timeout(dev) >= 0)
 281                                 alarm(udev_device_get_event_timeout(dev));
 282
 283                         /* execute RUN= */
 284                         if (err == 0 && !udev_event->ignore_device && udev_get_run(udev_event->udev))
 285                                 udev_event_execute_run(udev_event);
 286
 287                         /* reset alarm */
 288                         alarm(0);
 289
 290                         /* apply/restore inotify watch */
 291                         if (err == 0 && udev_event->inotify_watch) {
 292                                 udev_watch_begin(udev_event->udev, dev);
 293                                 udev_device_update_db(dev);
 294                         }
 295
 296                         /* send processed event back to libudev listeners */
 297                         udev_monitor_send_device(worker_monitor, NULL, dev);
 298
 299                         /* send back the result of the event execution */
 300                         msg.exitcode = err;
 301                         msg.pid = getpid();
 302                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 303
 304                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 305                         udev_event_unref(udev_event);
 306                         udev_device_unref(dev);
 307                         dev = NULL;
 308
 309                         /* wait for more device messages or signal from udevd */
 310                         while (!worker_exit) {
 311                                 int fdcount;
 312
 313                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 314                                 if (fdcount < 0)
 315                                         continue;
 316
 317                                 if (pmon.revents & POLLIN) {
 318                                         dev = udev_monitor_receive_device(worker_monitor);
 319                                         if (dev != NULL)
 320                                                 break;
 321                                 }
 322                         }
 323                 } while (dev != NULL);
 324
 325                 udev_monitor_unref(worker_monitor);
 326                 udev_log_close();
 327                 exit(0);
 328         }
 329         case -1:
 330                 udev_monitor_unref(worker_monitor);
 331                 event->state = EVENT_QUEUED;
 332                 free(worker);
 333                 err(event->udev, "fork of child failed: %m\n");
 334                 break;
 335         default:
 336                 /* close monitor, but keep address around */
 337                 udev_monitor_disconnect(worker_monitor);
 338                 worker->monitor = worker_monitor;
 339                 worker->pid = pid;
 340                 worker->state = WORKER_RUNNING;
 341                 worker->event = event;
 342                 event->state = EVENT_RUNNING;
 343                 udev_list_node_append(&worker->node, &worker_list);
 344                 childs++;
 345                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 346                 break;
 347         }
 348 }
 349
 350 static void event_run(struct event *event)
 351 {
 352         struct udev_list_node *loop;
 353
 354         udev_list_node_foreach(loop, &worker_list) {
 355                 struct worker *worker = node_to_worker(loop);
 356                 ssize_t count;
 357
 358                 if (worker->state != WORKER_IDLE)
 359                         continue;
 360
 361                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 362                 if (count < 0) {
 363                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 364                         kill(worker->pid, SIGKILL);
 365                         worker->state = WORKER_KILLED;
 366                         continue;
 367                 }
 368                 worker_ref(worker);
 369                 worker->event = event;
 370                 worker->state = WORKER_RUNNING;
 371                 event->state = EVENT_RUNNING;
 372                 return;
 373         }
 374
 375         if (childs >= max_childs) {
 376                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 377                 return;
 378         }
 379
 380         /* start new worker and pass initial device */
 381         worker_new(event);
 382 }
 383
 384 static void event_queue_insert(struct udev_device *dev)
 385 {
 386         struct event *event;
 387
 388         event = calloc(1, sizeof(struct event));
 389         if (event == NULL)
 390                 return;
 391
 392         event->udev = udev_device_get_udev(dev);
 393         event->dev = dev;
 394         event->seqnum = udev_device_get_seqnum(dev);
 395         event->devpath = udev_device_get_devpath(dev);
 396         event->devpath_len = strlen(event->devpath);
 397         event->devpath_old = udev_device_get_devpath_old(dev);
 398
 399         udev_queue_export_device_queued(udev_queue_export, dev);
 400         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 401              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 402
 403         event->state = EVENT_QUEUED;
 404         udev_list_node_append(&event->node, &event_list);
 405
 406         /* run all events with a timeout set immediately */
 407         if (udev_device_get_timeout(dev) > 0) {
 408                 worker_new(event);
 409                 return;
 410         }
 411 }
 412
 413 static void worker_kill(struct udev *udev, int retain)
 414 {
 415         struct udev_list_node *loop;
 416         int max;
 417
 418         if (childs <= retain)
 419                 return;
 420
 421         max = childs - retain;
 422
 423         udev_list_node_foreach(loop, &worker_list) {
 424                 struct worker *worker = node_to_worker(loop);
 425
 426                 if (max-- <= 0)
 427                         break;
 428
 429                 if (worker->state == WORKER_KILLED)
 430                         continue;
 431
 432                 worker->state = WORKER_KILLED;
 433                 kill(worker->pid, SIGTERM);
 434         }
 435 }
 436
 437 static int mem_size_mb(void)
 438 {
 439         FILE *f;
 440         char buf[4096];
 441         long int memsize = -1;
 442
 443         f = fopen("/proc/meminfo", "r");
 444         if (f == NULL)
 445                 return -1;
 446
 447         while (fgets(buf, sizeof(buf), f) != NULL) {
 448                 long int value;
 449
 450                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 451                         memsize = value / 1024;
 452                         break;
 453                 }
 454         }
 455
 456         fclose(f);
 457         return memsize;
 458 }
 459
 460 /* lookup event for identical, parent, child device */
 461 static int devpath_busy(struct event *event)
 462 {
 463         struct udev_list_node *loop;
 464         size_t common;
 465
 466         /* check if queue contains events we depend on */
 467         udev_list_node_foreach(loop, &event_list) {
 468                 struct event *loop_event = node_to_event(loop);
 469
 470                 /* we already found a later event, earlier can not block us, no need to check again */
 471                 if (loop_event->seqnum < event->delaying_seqnum)
 472                         continue;
 473
 474                 /* event we checked earlier still exists, no need to check again */
 475                 if (loop_event->seqnum == event->delaying_seqnum)
 476                         return 2;
 477
 478                 /* found ourself, no later event can block us */
 479                 if (loop_event->seqnum >= event->seqnum)
 480                         break;
 481
 482                 /* check our old name */
 483                 if (event->devpath_old != NULL)
 484                         if (strcmp(loop_event->devpath, event->devpath_old) == 0) {
 485                                 event->delaying_seqnum = loop_event->seqnum;
 486                                 return 3;
 487                         }
 488
 489                 /* compare devpath */
 490                 common = MIN(loop_event->devpath_len, event->devpath_len);
 491
 492                 /* one devpath is contained in the other? */
 493                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 494                         continue;
 495
 496                 /* identical device event found */
 497                 if (loop_event->devpath_len == event->devpath_len) {
 498                         event->delaying_seqnum = loop_event->seqnum;
 499                         return 4;
 500                 }
 501
 502                 /* parent device event found */
 503                 if (event->devpath[common] == '/') {
 504                         event->delaying_seqnum = loop_event->seqnum;
 505                         return 5;
 506                 }
 507
 508                 /* child device event found */
 509                 if (loop_event->devpath[common] == '/') {
 510                         event->delaying_seqnum = loop_event->seqnum;
 511                         return 6;
 512                 }
 513
 514                 /* no matching device */
 515                 continue;
 516         }
 517
 518         return 0;
 519 }
 520
 521 static void events_start(struct udev *udev)
 522 {
 523         struct udev_list_node *loop;
 524
 525         udev_list_node_foreach(loop, &event_list) {
 526                 struct event *event = node_to_event(loop);
 527
 528                 if (event->state != EVENT_QUEUED)
 529                         continue;
 530
 531                 /* do not start event if parent or child event is still running */
 532                 if (devpath_busy(event) != 0) {
 533                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 534                         continue;
 535                 }
 536
 537                 event_run(event);
 538         }
 539 }
 540
 541 static void worker_returned(void)
 542 {
 543         while (1) {
 544                 struct worker_message msg;
 545                 ssize_t size;
 546                 struct udev_list_node *loop;
 547
 548                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 549                 if (size != sizeof(struct worker_message))
 550                         break;
 551
 552                 /* lookup worker who sent the signal */
 553                 udev_list_node_foreach(loop, &worker_list) {
 554                         struct worker *worker = node_to_worker(loop);
 555
 556                         if (worker->pid != msg.pid)
 557                                 continue;
 558
 559                         /* worker returned */
 560                         worker->event->exitcode = msg.exitcode;
 561                         event_queue_delete(worker->event);
 562                         worker->event = NULL;
 563                         if (worker->state != WORKER_KILLED)
 564                                 worker->state = WORKER_IDLE;
 565                         worker_unref(worker);
 566                         break;
 567                 }
 568         }
 569 }
 570
 571 /* receive the udevd message from userspace */
 572 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 573 {
 574         struct udev *udev = udev_ctrl_get_udev(uctrl);
 575         struct udev_ctrl_msg *ctrl_msg;
 576         const char *str;
 577         int i;
 578
 579         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 580         if (ctrl_msg == NULL)
 581                 return;
 582
 583         i = udev_ctrl_get_set_log_level(ctrl_msg);
 584         if (i >= 0) {
 585                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 586                 udev_set_log_priority(udev, i);
 587                 worker_kill(udev, 0);
 588         }
 589
 590         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 591                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 592                 stop_exec_queue = true;
 593         }
 594
 595         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 596                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 597                 stop_exec_queue = false;
 598         }
 599
 600         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 601                 info(udev, "udevd message (RELOAD_RULES) received\n");
 602                 reload_config = true;
 603         }
 604
 605         str = udev_ctrl_get_set_env(ctrl_msg);
 606         if (str != NULL) {
 607                 char *key;
 608
 609                 key = strdup(str);
 610                 if (key != NULL) {
 611                         char *val;
 612
 613                         val = strchr(key, '=');
 614                         if (val != NULL) {
 615                                 val[0] = '\0';
 616                                 val = &val[1];
 617                                 if (val[0] == '\0') {
 618                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 619                                         udev_add_property(udev, key, NULL);
 620                                 } else {
 621                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 622                                         udev_add_property(udev, key, val);
 623                                 }
 624                         } else {
 625                                 err(udev, "wrong key format '%s'\n", key);
 626                         }
 627                         free(key);
 628                 }
 629                 worker_kill(udev, 0);
 630         }
 631
 632         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 633         if (i >= 0) {
 634                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 635                 max_childs = i;
 636         }
 637
 638         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 639         if (settle_pid > 0) {
 640                 info(udev, "udevd message (SETTLE) received\n");
 641                 kill(settle_pid, SIGUSR1);
 642                 settle_pid = 0;
 643         }
 644         udev_ctrl_msg_unref(ctrl_msg);
 645 }
 646
 647 /* read inotify messages */
 648 static int handle_inotify(struct udev *udev)
 649 {
 650         ssize_t nbytes, pos;
 651         char *buf;
 652         struct inotify_event *ev;
 653
 654         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 655                 return 0;
 656
 657         buf = malloc(nbytes);
 658         if (buf == NULL) {
 659                 err(udev, "error getting buffer for inotify\n");
 660                 return -1;
 661         }
 662
 663         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 664
 665         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 666                 struct udev_device *dev;
 667
 668                 ev = (struct inotify_event *)(buf + pos);
 669                 if (ev->len) {
 670                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 671                         reload_config = true;
 672                         continue;
 673                 }
 674
 675                 dev = udev_watch_lookup(udev, ev->wd);
 676                 if (dev != NULL) {
 677                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 678                         if (ev->mask & IN_CLOSE_WRITE) {
 679                                 char filename[UTIL_PATH_SIZE];
 680                                 int fd;
 681
 682                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 683                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 684                                 fd = open(filename, O_WRONLY);
 685                                 if (fd < 0 || write(fd, "change", 6) < 0)
 686                                         info(udev, "error writing uevent: %m\n");
 687                                 close(fd);
 688                         }
 689                         if (ev->mask & IN_IGNORED)
 690                                 udev_watch_end(udev, dev);
 691
 692                         udev_device_unref(dev);
 693                 }
 694
 695         }
 696
 697         free(buf);
 698         return 0;
 699 }
 700
 701 static void handle_signal(struct udev *udev, int signo)
 702 {
 703         switch (signo) {
 704         case SIGINT:
 705         case SIGTERM:
 706                 udev_exit = true;
 707                 break;
 708         case SIGCHLD:
 709                 while (1) {
 710                         pid_t pid;
 711                         int status;
 712                         struct udev_list_node *loop, *tmp;
 713
 714                         pid = waitpid(-1, &status, WNOHANG);
 715                         if (pid <= 0)
 716                                 break;
 717
 718                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 719                                 struct worker *worker = node_to_worker(loop);
 720
 721                                 if (worker->pid != pid)
 722                                         continue;
 723
 724                                 info(udev, "worker [%u] exit\n", pid);
 725                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 726                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 727                                         if (worker->event != NULL) {
 728                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 729                                                 worker->event->exitcode = -32;
 730                                                 event_queue_delete(worker->event);
 731                                                 /* drop reference from running event */
 732                                                 worker_unref(worker);
 733                                         }
 734                                 }
 735                                 worker_unref(worker);
 736                                 break;
 737                         }
 738                 }
 739                 break;
 740         case SIGHUP:
 741                 reload_config = true;
 742                 break;
 743         }
 744 }
 745
 746 static void startup_log(struct udev *udev)
 747 {
 748         FILE *f;
 749         char path[UTIL_PATH_SIZE];
 750         struct stat statbuf;
 751
 752         f = fopen("/dev/kmsg", "w");
 753         if (f != NULL)
 754                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 755
 756         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 757         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 758                 const char *depr_str =
 759                         "udev: missing sysfs features; please update the kernel "
 760                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 761                         "udev may fail to work correctly";
 762
 763                 if (f != NULL)
 764                         fprintf(f, "<3>%s\n", depr_str);
 765                 err(udev, "%s\n", depr_str);
 766                 sleep(3);
 767         }
 768
 769         if (f != NULL)
 770                 fclose(f);
 771 }
 772
 773 int main(int argc, char *argv[])
 774 {
 775         struct udev *udev;
 776         int fd;
 777         sigset_t mask;
 778         const char *value;
 779         int daemonize = false;
 780         int resolve_names = 1;
 781         static const struct option options[] = {
 782                 { "daemon", no_argument, NULL, 'd' },
 783                 { "debug-trace", no_argument, NULL, 't' },
 784                 { "debug", no_argument, NULL, 'D' },
 785                 { "help", no_argument, NULL, 'h' },
 786                 { "version", no_argument, NULL, 'V' },
 787                 { "resolve-names", required_argument, NULL, 'N' },
 788                 {}
 789         };
 790         int rc = 1;
 791
 792         udev = udev_new();
 793         if (udev == NULL)
 794                 goto exit;
 795
 796         udev_log_init("udevd");
 797         udev_set_log_fn(udev, log_fn);
 798         info(udev, "version %s\n", VERSION);
 799         udev_selinux_init(udev);
 800
 801         while (1) {
 802                 int option;
 803
 804                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 805                 if (option == -1)
 806                         break;
 807
 808                 switch (option) {
 809                 case 'd':
 810                         daemonize = true;
 811                         break;
 812                 case 't':
 813                         debug_trace = true;
 814                         break;
 815                 case 'D':
 816                         debug = true;
 817                         if (udev_get_log_priority(udev) < LOG_INFO)
 818                                 udev_set_log_priority(udev, LOG_INFO);
 819                         break;
 820                 case 'N':
 821                         if (strcmp (optarg, "early") == 0) {
 822                                 resolve_names = 1;
 823                         } else if (strcmp (optarg, "late") == 0) {
 824                                 resolve_names = 0;
 825                         } else if (strcmp (optarg, "never") == 0) {
 826                                 resolve_names = -1;
 827                         } else {
 828                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 829                                 err(udev, "resolve-names must be early, late or never\n");
 830                                 goto exit;
 831                         }
 832                         break;
 833                 case 'h':
 834                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 835                                "[--resolve-names=early|late|never] [--version]\n");
 836                         goto exit;
 837                 case 'V':
 838                         printf("%s\n", VERSION);
 839                         goto exit;
 840                 default:
 841                         goto exit;
 842                 }
 843         }
 844
 845         if (getuid() != 0) {
 846                 fprintf(stderr, "root privileges required\n");
 847                 err(udev, "root privileges required\n");
 848                 goto exit;
 849         }
 850
 851         /* make sure std{in,out,err} fd's are in a sane state */
 852         fd = open("/dev/null", O_RDWR);
 853         if (fd < 0) {
 854                 fprintf(stderr, "cannot open /dev/null\n");
 855                 err(udev, "cannot open /dev/null\n");
 856         }
 857         if (write(STDOUT_FILENO, 0, 0) < 0)
 858                 dup2(fd, STDOUT_FILENO);
 859         if (write(STDERR_FILENO, 0, 0) < 0)
 860                 dup2(fd, STDERR_FILENO);
 861
 862         /* init control socket, bind() ensures, that only one udevd instance is running */
 863         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 864         if (udev_ctrl == NULL) {
 865                 fprintf(stderr, "error initializing control socket");
 866                 err(udev, "error initializing udevd socket");
 867                 rc = 1;
 868                 goto exit;
 869         }
 870         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 871                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 872                 err(udev, "error binding control socket, seems udevd is already running\n");
 873                 rc = 1;
 874                 goto exit;
 875         }
 876         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 877
 878         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 879         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 880                 fprintf(stderr, "error initializing netlink socket\n");
 881                 err(udev, "error initializing netlink socket\n");
 882                 rc = 3;
 883                 goto exit;
 884         }
 885         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 886         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 887
 888         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 889         if (pfd[FD_INOTIFY].fd < 0) {
 890                 fprintf(stderr, "error initializing inotify\n");
 891                 err(udev, "error initializing inotify\n");
 892                 rc = 4;
 893                 goto exit;
 894         }
 895
 896         if (udev_get_rules_path(udev) != NULL) {
 897                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 898                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 899         } else {
 900                 char filename[UTIL_PATH_SIZE];
 901
 902                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 903                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 904                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 905                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 906
 907                 /* watch dynamic rules directory */
 908                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 909                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 910                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 911         }
 912         udev_watch_restore(udev);
 913
 914         /* block and listen to all signals on signalfd */
 915         sigfillset(&mask);
 916         sigprocmask(SIG_SETMASK, &mask, NULL);
 917         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 918         if (pfd[FD_SIGNAL].fd < 0) {
 919                 fprintf(stderr, "error getting signalfd\n");
 920                 err(udev, "error getting signalfd\n");
 921                 rc = 5;
 922                 goto exit;
 923         }
 924
 925         /* unnamed socket from workers to the main daemon */
 926         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 927                 fprintf(stderr, "error getting socketpair\n");
 928                 err(udev, "error getting socketpair\n");
 929                 rc = 6;
 930                 goto exit;
 931         }
 932         pfd[FD_WORKER].fd = worker_watch[READ_END];
 933         util_set_fd_cloexec(worker_watch[WRITE_END]);
 934
 935         rules = udev_rules_new(udev, resolve_names);
 936         if (rules == NULL) {
 937                 err(udev, "error reading rules\n");
 938                 goto exit;
 939         }
 940
 941         udev_queue_export = udev_queue_export_new(udev);
 942         if (udev_queue_export == NULL) {
 943                 err(udev, "error creating queue file\n");
 944                 goto exit;
 945         }
 946
 947         if (daemonize) {
 948                 pid_t pid;
 949
 950                 pid = fork();
 951                 switch (pid) {
 952                 case 0:
 953                         break;
 954                 case -1:
 955                         err(udev, "fork of daemon failed: %m\n");
 956                         rc = 4;
 957                         goto exit;
 958                 default:
 959                         rc = 0;
 960                         goto exit;
 961                 }
 962         }
 963
 964         startup_log(udev);
 965
 966         /* redirect std{out,err} */
 967         if (!debug && !debug_trace) {
 968                 dup2(fd, STDIN_FILENO);
 969                 dup2(fd, STDOUT_FILENO);
 970                 dup2(fd, STDERR_FILENO);
 971         }
 972         if (fd > STDERR_FILENO)
 973                 close(fd);
 974
 975         /* set scheduling priority for the daemon */
 976         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 977
 978         chdir("/");
 979         umask(022);
 980         setsid();
 981
 982         /* OOM_DISABLE == -17 */
 983         fd = open("/proc/self/oom_adj", O_RDWR);
 984         if (fd < 0) {
 985                 err(udev, "error disabling OOM: %m\n");
 986         } else {
 987                 write(fd, "-17", 3);
 988                 close(fd);
 989         }
 990
 991         /* in trace mode run one event after the other */
 992         if (debug_trace) {
 993                 max_childs = 1;
 994         } else {
 995                 int memsize = mem_size_mb();
 996
 997                 if (memsize > 0)
 998                         max_childs = 128 + (memsize / 8);
 999                 else
1000                         max_childs = 128;
1001         }
1002
1003         /* possibly overwrite maximum limit of executed events */
1004         value = getenv("UDEVD_MAX_CHILDS");
1005         if (value)
1006                 max_childs = strtoul(value, NULL, 10);
1007         info(udev, "initialize max_childs to %u\n", max_childs);
1008
1009         udev_list_init(&event_list);
1010         udev_list_init(&worker_list);
1011
1012         while (!udev_exit) {
1013                 int fdcount;
1014                 int timeout;
1015
1016                 /* set timeout to kill idle workers */
1017                 if (udev_list_is_empty(&event_list) && childs > 2)
1018                         timeout = 3 * 1000;
1019                 else
1020                         timeout = -1;
1021                 /* wait for events */
1022                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1023                 if (fdcount < 0)
1024                         continue;
1025
1026                 /* timeout - kill idle workers */
1027                 if (fdcount == 0)
1028                         worker_kill(udev, 2);
1029
1030                 /* event has finished */
1031                 if (pfd[FD_WORKER].revents & POLLIN)
1032                         worker_returned();
1033
1034                 /* get kernel uevent */
1035                 if (pfd[FD_NETLINK].revents & POLLIN) {
1036                         struct udev_device *dev;
1037
1038                         dev = udev_monitor_receive_device(monitor);
1039                         if (dev != NULL)
1040                                 event_queue_insert(dev);
1041                         else
1042                                 udev_device_unref(dev);
1043                 }
1044
1045                 /* start new events */
1046                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1047                         events_start(udev);
1048
1049                 /* get signal */
1050                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1051                         struct signalfd_siginfo fdsi;
1052                         ssize_t size;
1053
1054                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1055                         if (size == sizeof(struct signalfd_siginfo))
1056                                 handle_signal(udev, fdsi.ssi_signo);
1057                 }
1058
1059                 /* device node and rules directory inotify watch */
1060                 if (pfd[FD_INOTIFY].revents & POLLIN)
1061                         handle_inotify(udev);
1062
1063                 /*
1064                  * get control message
1065                  *
1066                  * This needs to be after the inotify handling, to make sure,
1067                  * that the settle signal is send back after the possibly generated
1068                  * "change" events by the inotify device node watch.
1069                  */
1070                 if (pfd[FD_CONTROL].revents & POLLIN)
1071                         handle_ctrl_msg(udev_ctrl);
1072
1073                 /* rules changed, set by inotify or a HUP signal */
1074                 if (reload_config) {
1075                         struct udev_rules *rules_new;
1076
1077                         worker_kill(udev, 0);
1078                         rules_new = udev_rules_new(udev, resolve_names);
1079                         if (rules_new != NULL) {
1080                                 udev_rules_unref(rules);
1081                                 rules = rules_new;
1082                         }
1083                         reload_config = 0;
1084                 }
1085         }
1086
1087         udev_queue_export_cleanup(udev_queue_export);
1088         rc = 0;
1089 exit:
1090         udev_queue_export_unref(udev_queue_export);
1091         udev_rules_unref(rules);
1092         udev_ctrl_unref(udev_ctrl);
1093         if (pfd[FD_SIGNAL].fd >= 0)
1094                 close(pfd[FD_SIGNAL].fd);
1095         if (worker_watch[READ_END] >= 0)
1096                 close(worker_watch[READ_END]);
1097         if (worker_watch[WRITE_END] >= 0)
1098                 close(worker_watch[WRITE_END]);
1099         udev_monitor_unref(monitor);
1100         udev_selinux_exit(udev);
1101         udev_unref(udev);
1102         udev_log_close();
1103         return rc;
1104 }