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