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