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/time.h>
  35 #include <sys/prctl.h>
  36 #include <sys/socket.h>
  37 #include <sys/signalfd.h>
  38 #include <sys/select.h>
  39 #include <sys/poll.h>
  40 #include <sys/wait.h>
  41 #include <sys/stat.h>
  42 #include <sys/ioctl.h>
  43 #include <sys/inotify.h>
  44
  45 #include "udev.h"
  46
  47 #define UDEVD_PRIORITY                  -4
  48 #define UDEV_PRIORITY                   -2
  49
  50 static bool debug;
  51
  52 static void log_fn(struct udev *udev, int priority,
  53                    const char *file, int line, const char *fn,
  54                    const char *format, va_list args)
  55 {
  56         if (debug) {
  57                 char buf[1024];
  58                 struct timeval tv;
  59                 struct timezone tz;
  60
  61                 vsnprintf(buf, sizeof(buf), format, args);
  62                 gettimeofday(&tv, &tz);
  63                 fprintf(stderr, "%llu.%06u [%u] %s: %s",
  64                         (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
  65                         (int) getpid(), fn, buf);
  66         } else {
  67                 vsyslog(priority, format, args);
  68         }
  69 }
  70
  71 static bool debug_trace;
  72 static struct udev_rules *rules;
  73 static struct udev_queue_export *udev_queue_export;
  74 static struct udev_ctrl *udev_ctrl;
  75 static struct udev_monitor *monitor;
  76 static int worker_watch[2];
  77 static pid_t settle_pid;
  78 static bool stop_exec_queue;
  79 static bool reload_config;
  80 static int max_childs;
  81 static int childs;
  82 static sigset_t orig_sigmask;
  83 static struct udev_list_node event_list;
  84 static struct udev_list_node worker_list;
  85 static bool udev_exit;
  86 static volatile sig_atomic_t worker_exit;
  87
  88 enum poll_fd {
  89         FD_CONTROL,
  90         FD_NETLINK,
  91         FD_INOTIFY,
  92         FD_SIGNAL,
  93         FD_WORKER,
  94 };
  95
  96 static struct pollfd pfd[] = {
  97         [FD_NETLINK] = { .events = POLLIN },
  98         [FD_WORKER] =  { .events = POLLIN },
  99         [FD_SIGNAL] =  { .events = POLLIN },
 100         [FD_INOTIFY] = { .events = POLLIN },
 101         [FD_CONTROL] = { .events = POLLIN },
 102 };
 103
 104 enum event_state {
 105         EVENT_UNDEF,
 106         EVENT_QUEUED,
 107         EVENT_RUNNING,
 108 };
 109
 110 struct event {
 111         struct udev_list_node node;
 112         struct udev *udev;
 113         struct udev_device *dev;
 114         enum event_state state;
 115         int exitcode;
 116         unsigned long long int delaying_seqnum;
 117         unsigned long long int seqnum;
 118         const char *devpath;
 119         size_t devpath_len;
 120         const char *devpath_old;
 121         dev_t devnum;
 122         bool is_block;
 123 };
 124
 125 static struct event *node_to_event(struct udev_list_node *node)
 126 {
 127         char *event;
 128
 129         event = (char *)node;
 130         event -= offsetof(struct event, node);
 131         return (struct event *)event;
 132 }
 133
 134 enum worker_state {
 135         WORKER_UNDEF,
 136         WORKER_RUNNING,
 137         WORKER_IDLE,
 138         WORKER_KILLED,
 139 };
 140
 141 struct worker {
 142         struct udev_list_node node;
 143         struct udev *udev;
 144         int refcount;
 145         pid_t pid;
 146         struct udev_monitor *monitor;
 147         enum worker_state state;
 148         struct event *event;
 149 };
 150
 151 /* passed from worker to main process */
 152 struct worker_message {
 153         pid_t pid;
 154         int exitcode;
 155 };
 156
 157 static struct worker *node_to_worker(struct udev_list_node *node)
 158 {
 159         char *worker;
 160
 161         worker = (char *)node;
 162         worker -= offsetof(struct worker, node);
 163         return (struct worker *)worker;
 164 }
 165
 166 static void event_queue_delete(struct event *event)
 167 {
 168         udev_list_node_remove(&event->node);
 169
 170         /* mark as failed, if "add" event returns non-zero */
 171         if (event->exitcode != 0 && strcmp(udev_device_get_action(event->dev), "add") == 0)
 172                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 173         else
 174                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 175
 176         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 177         udev_device_unref(event->dev);
 178         free(event);
 179 }
 180
 181 static void event_sig_handler(int signum)
 182 {
 183         switch (signum) {
 184         case SIGALRM:
 185                 _exit(1);
 186                 break;
 187         case SIGTERM:
 188                 worker_exit = true;
 189                 break;
 190         }
 191 }
 192
 193 static struct worker *worker_ref(struct worker *worker)
 194 {
 195         worker->refcount++;
 196         return worker;
 197 }
 198
 199 static void worker_unref(struct worker *worker)
 200 {
 201         worker->refcount--;
 202         if (worker->refcount > 0)
 203                 return;
 204
 205         udev_list_node_remove(&worker->node);
 206         udev_monitor_unref(worker->monitor);
 207         childs--;
 208         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 209         free(worker);
 210 }
 211
 212 static void worker_new(struct event *event)
 213 {
 214         struct worker *worker;
 215         struct udev_monitor *worker_monitor;
 216         pid_t pid;
 217         struct sigaction act;
 218
 219         /* listen for new events */
 220         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 221         if (worker_monitor == NULL)
 222                 return;
 223         /* allow the main daemon netlink address to send devices to the worker */
 224         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 225         udev_monitor_enable_receiving(worker_monitor);
 226
 227         worker = calloc(1, sizeof(struct worker));
 228         if (worker == NULL)
 229                 return;
 230         /* worker + event reference */
 231         worker->refcount = 2;
 232         worker->udev = event->udev;
 233
 234         pid = fork();
 235         switch (pid) {
 236         case 0: {
 237                 sigset_t sigmask;
 238                 struct udev_device *dev;
 239                 struct pollfd pmon = {
 240                         .fd = udev_monitor_get_fd(worker_monitor),
 241                         .events = POLLIN,
 242                 };
 243
 244                 udev_queue_export_unref(udev_queue_export);
 245                 udev_monitor_unref(monitor);
 246                 udev_ctrl_unref(udev_ctrl);
 247                 close(pfd[FD_SIGNAL].fd);
 248                 close(worker_watch[READ_END]);
 249                 udev_log_close();
 250                 udev_log_init("udevd-work");
 251                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 252
 253                 /* set signal handlers */
 254                 memset(&act, 0x00, sizeof(act));
 255                 act.sa_handler = event_sig_handler;
 256                 sigemptyset (&act.sa_mask);
 257                 act.sa_flags = 0;
 258                 sigaction(SIGTERM, &act, NULL);
 259                 sigaction(SIGALRM, &act, NULL);
 260
 261                 /* unblock SIGALRM */
 262                 sigfillset(&sigmask);
 263                 sigdelset(&sigmask, SIGALRM);
 264                 sigprocmask(SIG_SETMASK, &sigmask, NULL);
 265                 /* SIGTERM is unblocked in ppoll() */
 266                 sigdelset(&sigmask, SIGTERM);
 267
 268                 /* request TERM signal if parent exits */
 269                 prctl(PR_SET_PDEATHSIG, SIGTERM);
 270
 271                 /* initial device */
 272                 dev = event->dev;
 273
 274                 do {
 275                         struct udev_event *udev_event;
 276                         struct worker_message msg = {};
 277                         int err;
 278                         int failed = 0;
 279
 280                         info(event->udev, "seq %llu running\n", udev_device_get_seqnum(dev));
 281                         udev_event = udev_event_new(dev);
 282                         if (udev_event == NULL)
 283                                 _exit(3);
 284
 285                         /* set timeout to prevent hanging processes */
 286                         alarm(UDEV_EVENT_TIMEOUT);
 287
 288                         /* apply rules, create node, symlinks */
 289                         err = udev_event_execute_rules(udev_event, rules);
 290
 291                         /* rules may change/disable the timeout */
 292                         if (udev_device_get_event_timeout(dev) >= 0)
 293                                 alarm(udev_device_get_event_timeout(dev));
 294
 295                         /* execute RUN= */
 296                         if (err == 0 && udev_get_run(udev_event->udev))
 297                                 failed = udev_event_execute_run(udev_event,
 298                                                                 &orig_sigmask);
 299
 300                         /* reset alarm */
 301                         alarm(0);
 302
 303                         /* apply/restore inotify watch */
 304                         if (err == 0 && udev_event->inotify_watch) {
 305                                 udev_watch_begin(udev_event->udev, dev);
 306                                 udev_device_update_db(dev);
 307                         }
 308
 309                         /* send processed event back to libudev listeners */
 310                         udev_monitor_send_device(worker_monitor, NULL, dev);
 311
 312                         /* send back the result of the event execution */
 313                         if (err != 0)
 314                                 msg.exitcode = err;
 315                         else if (failed != 0)
 316                                 msg.exitcode = failed;
 317                         msg.pid = getpid();
 318                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 319
 320                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 321                         udev_event_unref(udev_event);
 322                         udev_device_unref(dev);
 323                         dev = NULL;
 324
 325                         /* wait for more device messages or signal from udevd */
 326                         while (!worker_exit) {
 327                                 int fdcount;
 328
 329                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 330                                 if (fdcount < 0)
 331                                         continue;
 332
 333                                 if (pmon.revents & POLLIN) {
 334                                         dev = udev_monitor_receive_device(worker_monitor);
 335                                         if (dev != NULL)
 336                                                 break;
 337                                 }
 338                         }
 339                 } while (dev != NULL);
 340
 341                 udev_monitor_unref(worker_monitor);
 342                 udev_log_close();
 343                 exit(0);
 344         }
 345         case -1:
 346                 udev_monitor_unref(worker_monitor);
 347                 event->state = EVENT_QUEUED;
 348                 free(worker);
 349                 err(event->udev, "fork of child failed: %m\n");
 350                 break;
 351         default:
 352                 /* close monitor, but keep address around */
 353                 udev_monitor_disconnect(worker_monitor);
 354                 worker->monitor = worker_monitor;
 355                 worker->pid = pid;
 356                 worker->state = WORKER_RUNNING;
 357                 worker->event = event;
 358                 event->state = EVENT_RUNNING;
 359                 udev_list_node_append(&worker->node, &worker_list);
 360                 childs++;
 361                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 362                 break;
 363         }
 364 }
 365
 366 static void event_run(struct event *event)
 367 {
 368         struct udev_list_node *loop;
 369
 370         udev_list_node_foreach(loop, &worker_list) {
 371                 struct worker *worker = node_to_worker(loop);
 372                 ssize_t count;
 373
 374                 if (worker->state != WORKER_IDLE)
 375                         continue;
 376
 377                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 378                 if (count < 0) {
 379                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 380                         kill(worker->pid, SIGKILL);
 381                         worker->state = WORKER_KILLED;
 382                         continue;
 383                 }
 384                 worker_ref(worker);
 385                 worker->event = event;
 386                 worker->state = WORKER_RUNNING;
 387                 event->state = EVENT_RUNNING;
 388                 return;
 389         }
 390
 391         if (childs >= max_childs) {
 392                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 393                 return;
 394         }
 395
 396         /* start new worker and pass initial device */
 397         worker_new(event);
 398 }
 399
 400 static void event_queue_insert(struct udev_device *dev)
 401 {
 402         struct event *event;
 403
 404         event = calloc(1, sizeof(struct event));
 405         if (event == NULL)
 406                 return;
 407
 408         event->udev = udev_device_get_udev(dev);
 409         event->dev = dev;
 410         event->seqnum = udev_device_get_seqnum(dev);
 411         event->devpath = udev_device_get_devpath(dev);
 412         event->devpath_len = strlen(event->devpath);
 413         event->devpath_old = udev_device_get_devpath_old(dev);
 414         event->devnum = udev_device_get_devnum(dev);
 415         event->is_block = (strcmp("block", udev_device_get_subsystem(dev)) == 0);
 416
 417         udev_queue_export_device_queued(udev_queue_export, dev);
 418         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 419              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 420
 421         event->state = EVENT_QUEUED;
 422         udev_list_node_append(&event->node, &event_list);
 423
 424         /* run all events with a timeout set immediately */
 425         if (udev_device_get_timeout(dev) > 0) {
 426                 worker_new(event);
 427                 return;
 428         }
 429 }
 430
 431 static void worker_kill(struct udev *udev, int retain)
 432 {
 433         struct udev_list_node *loop;
 434         int max;
 435
 436         if (childs <= retain)
 437                 return;
 438
 439         max = childs - retain;
 440
 441         udev_list_node_foreach(loop, &worker_list) {
 442                 struct worker *worker = node_to_worker(loop);
 443
 444                 if (max-- <= 0)
 445                         break;
 446
 447                 if (worker->state == WORKER_KILLED)
 448                         continue;
 449
 450                 worker->state = WORKER_KILLED;
 451                 kill(worker->pid, SIGTERM);
 452         }
 453 }
 454
 455 static int mem_size_mb(void)
 456 {
 457         FILE *f;
 458         char buf[4096];
 459         long int memsize = -1;
 460
 461         f = fopen("/proc/meminfo", "r");
 462         if (f == NULL)
 463                 return -1;
 464
 465         while (fgets(buf, sizeof(buf), f) != NULL) {
 466                 long int value;
 467
 468                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 469                         memsize = value / 1024;
 470                         break;
 471                 }
 472         }
 473
 474         fclose(f);
 475         return memsize;
 476 }
 477
 478 /* lookup event for identical, parent, child device */
 479 static bool is_devpath_busy(struct event *event)
 480 {
 481         struct udev_list_node *loop;
 482         size_t common;
 483
 484         /* check if queue contains events we depend on */
 485         udev_list_node_foreach(loop, &event_list) {
 486                 struct event *loop_event = node_to_event(loop);
 487
 488                 /* we already found a later event, earlier can not block us, no need to check again */
 489                 if (loop_event->seqnum < event->delaying_seqnum)
 490                         continue;
 491
 492                 /* event we checked earlier still exists, no need to check again */
 493                 if (loop_event->seqnum == event->delaying_seqnum)
 494                         return true;
 495
 496                 /* found ourself, no later event can block us */
 497                 if (loop_event->seqnum >= event->seqnum)
 498                         break;
 499
 500                 /* check major/minor */
 501                 if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
 502                         return true;
 503
 504                 /* check our old name */
 505                 if (event->devpath_old != NULL && strcmp(loop_event->devpath, event->devpath_old) == 0) {
 506                         event->delaying_seqnum = loop_event->seqnum;
 507                         return true;
 508                 }
 509
 510                 /* compare devpath */
 511                 common = MIN(loop_event->devpath_len, event->devpath_len);
 512
 513                 /* one devpath is contained in the other? */
 514                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 515                         continue;
 516
 517                 /* identical device event found */
 518                 if (loop_event->devpath_len == event->devpath_len) {
 519                         event->delaying_seqnum = loop_event->seqnum;
 520                         return true;
 521                 }
 522
 523                 /* parent device event found */
 524                 if (event->devpath[common] == '/') {
 525                         event->delaying_seqnum = loop_event->seqnum;
 526                         return true;
 527                 }
 528
 529                 /* child device event found */
 530                 if (loop_event->devpath[common] == '/') {
 531                         event->delaying_seqnum = loop_event->seqnum;
 532                         return true;
 533                 }
 534
 535                 /* no matching device */
 536                 continue;
 537         }
 538
 539         return false;
 540 }
 541
 542 static void events_start(struct udev *udev)
 543 {
 544         struct udev_list_node *loop;
 545
 546         udev_list_node_foreach(loop, &event_list) {
 547                 struct event *event = node_to_event(loop);
 548
 549                 if (event->state != EVENT_QUEUED)
 550                         continue;
 551
 552                 /* do not start event if parent or child event is still running */
 553                 if (is_devpath_busy(event)) {
 554                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 555                         continue;
 556                 }
 557
 558                 event_run(event);
 559         }
 560 }
 561
 562 static void worker_returned(void)
 563 {
 564         while (1) {
 565                 struct worker_message msg;
 566                 ssize_t size;
 567                 struct udev_list_node *loop;
 568
 569                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 570                 if (size != sizeof(struct worker_message))
 571                         break;
 572
 573                 /* lookup worker who sent the signal */
 574                 udev_list_node_foreach(loop, &worker_list) {
 575                         struct worker *worker = node_to_worker(loop);
 576
 577                         if (worker->pid != msg.pid)
 578                                 continue;
 579
 580                         /* worker returned */
 581                         worker->event->exitcode = msg.exitcode;
 582                         event_queue_delete(worker->event);
 583                         worker->event = NULL;
 584                         if (worker->state != WORKER_KILLED)
 585                                 worker->state = WORKER_IDLE;
 586                         worker_unref(worker);
 587                         break;
 588                 }
 589         }
 590 }
 591
 592 /* receive the udevd message from userspace */
 593 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 594 {
 595         struct udev *udev = udev_ctrl_get_udev(uctrl);
 596         struct udev_ctrl_msg *ctrl_msg;
 597         const char *str;
 598         int i;
 599
 600         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 601         if (ctrl_msg == NULL)
 602                 return;
 603
 604         i = udev_ctrl_get_set_log_level(ctrl_msg);
 605         if (i >= 0) {
 606                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 607                 udev_set_log_priority(udev, i);
 608                 worker_kill(udev, 0);
 609         }
 610
 611         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 612                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 613                 stop_exec_queue = true;
 614         }
 615
 616         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 617                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 618                 stop_exec_queue = false;
 619         }
 620
 621         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 622                 info(udev, "udevd message (RELOAD_RULES) received\n");
 623                 reload_config = true;
 624         }
 625
 626         str = udev_ctrl_get_set_env(ctrl_msg);
 627         if (str != NULL) {
 628                 char *key;
 629
 630                 key = strdup(str);
 631                 if (key != NULL) {
 632                         char *val;
 633
 634                         val = strchr(key, '=');
 635                         if (val != NULL) {
 636                                 val[0] = '\0';
 637                                 val = &val[1];
 638                                 if (val[0] == '\0') {
 639                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 640                                         udev_add_property(udev, key, NULL);
 641                                 } else {
 642                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 643                                         udev_add_property(udev, key, val);
 644                                 }
 645                         } else {
 646                                 err(udev, "wrong key format '%s'\n", key);
 647                         }
 648                         free(key);
 649                 }
 650                 worker_kill(udev, 0);
 651         }
 652
 653         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 654         if (i >= 0) {
 655                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 656                 max_childs = i;
 657         }
 658
 659         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 660         if (settle_pid > 0) {
 661                 info(udev, "udevd message (SETTLE) received\n");
 662                 kill(settle_pid, SIGUSR1);
 663                 settle_pid = 0;
 664         }
 665         udev_ctrl_msg_unref(ctrl_msg);
 666 }
 667
 668 /* read inotify messages */
 669 static int handle_inotify(struct udev *udev)
 670 {
 671         int nbytes, pos;
 672         char *buf;
 673         struct inotify_event *ev;
 674
 675         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 676                 return 0;
 677
 678         buf = malloc(nbytes);
 679         if (buf == NULL) {
 680                 err(udev, "error getting buffer for inotify\n");
 681                 return -1;
 682         }
 683
 684         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 685
 686         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 687                 struct udev_device *dev;
 688
 689                 ev = (struct inotify_event *)(buf + pos);
 690                 if (ev->len) {
 691                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 692                         reload_config = true;
 693                         continue;
 694                 }
 695
 696                 dev = udev_watch_lookup(udev, ev->wd);
 697                 if (dev != NULL) {
 698                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 699                         if (ev->mask & IN_CLOSE_WRITE) {
 700                                 char filename[UTIL_PATH_SIZE];
 701                                 int fd;
 702
 703                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 704                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 705                                 fd = open(filename, O_WRONLY);
 706                                 if (fd < 0 || write(fd, "change", 6) < 0)
 707                                         info(udev, "error writing uevent: %m\n");
 708                                 close(fd);
 709                         }
 710                         if (ev->mask & IN_IGNORED)
 711                                 udev_watch_end(udev, dev);
 712
 713                         udev_device_unref(dev);
 714                 }
 715
 716         }
 717
 718         free(buf);
 719         return 0;
 720 }
 721
 722 static void handle_signal(struct udev *udev, int signo)
 723 {
 724         switch (signo) {
 725         case SIGINT:
 726         case SIGTERM:
 727                 udev_exit = true;
 728                 break;
 729         case SIGCHLD:
 730                 while (1) {
 731                         pid_t pid;
 732                         int status;
 733                         struct udev_list_node *loop, *tmp;
 734
 735                         pid = waitpid(-1, &status, WNOHANG);
 736                         if (pid <= 0)
 737                                 break;
 738
 739                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 740                                 struct worker *worker = node_to_worker(loop);
 741
 742                                 if (worker->pid != pid)
 743                                         continue;
 744
 745                                 info(udev, "worker [%u] exit\n", pid);
 746                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 747                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 748                                         if (worker->event != NULL) {
 749                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 750                                                 worker->event->exitcode = -32;
 751                                                 event_queue_delete(worker->event);
 752                                                 /* drop reference from running event */
 753                                                 worker_unref(worker);
 754                                         }
 755                                 }
 756                                 worker_unref(worker);
 757                                 break;
 758                         }
 759                 }
 760                 break;
 761         case SIGHUP:
 762                 reload_config = true;
 763                 break;
 764         }
 765 }
 766
 767 static void startup_log(struct udev *udev)
 768 {
 769         FILE *f;
 770         char path[UTIL_PATH_SIZE];
 771         struct stat statbuf;
 772
 773         f = fopen("/dev/kmsg", "w");
 774         if (f != NULL)
 775                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 776
 777         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 778         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 779                 const char *depr_str =
 780                         "udev: missing sysfs features; please update the kernel "
 781                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 782                         "udev may fail to work correctly";
 783
 784                 if (f != NULL)
 785                         fprintf(f, "<3>%s\n", depr_str);
 786                 err(udev, "%s\n", depr_str);
 787                 sleep(15);
 788         }
 789
 790         if (f != NULL)
 791                 fclose(f);
 792 }
 793
 794 int main(int argc, char *argv[])
 795 {
 796         struct udev *udev;
 797         int fd;
 798         sigset_t mask;
 799         const char *value;
 800         int daemonize = false;
 801         int resolve_names = 1;
 802         static const struct option options[] = {
 803                 { "daemon", no_argument, NULL, 'd' },
 804                 { "debug-trace", no_argument, NULL, 't' },
 805                 { "debug", no_argument, NULL, 'D' },
 806                 { "help", no_argument, NULL, 'h' },
 807                 { "version", no_argument, NULL, 'V' },
 808                 { "resolve-names", required_argument, NULL, 'N' },
 809                 {}
 810         };
 811         int rc = 1;
 812
 813         udev = udev_new();
 814         if (udev == NULL)
 815                 goto exit;
 816
 817         udev_log_init("udevd");
 818         udev_set_log_fn(udev, log_fn);
 819         info(udev, "version %s\n", VERSION);
 820         udev_selinux_init(udev);
 821
 822         while (1) {
 823                 int option;
 824
 825                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 826                 if (option == -1)
 827                         break;
 828
 829                 switch (option) {
 830                 case 'd':
 831                         daemonize = true;
 832                         break;
 833                 case 't':
 834                         debug_trace = true;
 835                         break;
 836                 case 'D':
 837                         debug = true;
 838                         if (udev_get_log_priority(udev) < LOG_INFO)
 839                                 udev_set_log_priority(udev, LOG_INFO);
 840                         break;
 841                 case 'N':
 842                         if (strcmp (optarg, "early") == 0) {
 843                                 resolve_names = 1;
 844                         } else if (strcmp (optarg, "late") == 0) {
 845                                 resolve_names = 0;
 846                         } else if (strcmp (optarg, "never") == 0) {
 847                                 resolve_names = -1;
 848                         } else {
 849                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 850                                 err(udev, "resolve-names must be early, late or never\n");
 851                                 goto exit;
 852                         }
 853                         break;
 854                 case 'h':
 855                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 856                                "[--resolve-names=early|late|never] [--version]\n");
 857                         goto exit;
 858                 case 'V':
 859                         printf("%s\n", VERSION);
 860                         goto exit;
 861                 default:
 862                         goto exit;
 863                 }
 864         }
 865
 866         if (getuid() != 0) {
 867                 fprintf(stderr, "root privileges required\n");
 868                 err(udev, "root privileges required\n");
 869                 goto exit;
 870         }
 871
 872         /* make sure std{in,out,err} fd's are in a sane state */
 873         fd = open("/dev/null", O_RDWR);
 874         if (fd < 0) {
 875                 fprintf(stderr, "cannot open /dev/null\n");
 876                 err(udev, "cannot open /dev/null\n");
 877         }
 878         if (write(STDOUT_FILENO, 0, 0) < 0)
 879                 dup2(fd, STDOUT_FILENO);
 880         if (write(STDERR_FILENO, 0, 0) < 0)
 881                 dup2(fd, STDERR_FILENO);
 882
 883         /* init control socket, bind() ensures, that only one udevd instance is running */
 884         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 885         if (udev_ctrl == NULL) {
 886                 fprintf(stderr, "error initializing control socket");
 887                 err(udev, "error initializing udevd socket");
 888                 rc = 1;
 889                 goto exit;
 890         }
 891         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 892                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 893                 err(udev, "error binding control socket, seems udevd is already running\n");
 894                 rc = 1;
 895                 goto exit;
 896         }
 897         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 898
 899         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 900         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 901                 fprintf(stderr, "error initializing netlink socket\n");
 902                 err(udev, "error initializing netlink socket\n");
 903                 rc = 3;
 904                 goto exit;
 905         }
 906         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 907         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 908
 909         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 910         if (pfd[FD_INOTIFY].fd < 0) {
 911                 fprintf(stderr, "error initializing inotify\n");
 912                 err(udev, "error initializing inotify\n");
 913                 rc = 4;
 914                 goto exit;
 915         }
 916
 917         if (udev_get_rules_path(udev) != NULL) {
 918                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 919                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 920         } else {
 921                 char filename[UTIL_PATH_SIZE];
 922                 struct stat statbuf;
 923
 924                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 925                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 926                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 927                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 928
 929                 /* watch dynamic rules directory */
 930                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 931                 if (stat(filename, &statbuf) != 0) {
 932                         util_create_path(udev, filename);
 933                         udev_selinux_setfscreatecon(udev, filename, S_IFDIR|0755);
 934                         mkdir(filename, 0755);
 935                         udev_selinux_resetfscreatecon(udev);
 936                 }
 937                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 938                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 939         }
 940         udev_watch_restore(udev);
 941
 942         /* block and listen to all signals on signalfd */
 943         sigfillset(&mask);
 944         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
 945         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 946         if (pfd[FD_SIGNAL].fd < 0) {
 947                 fprintf(stderr, "error getting signalfd\n");
 948                 err(udev, "error getting signalfd\n");
 949                 rc = 5;
 950                 goto exit;
 951         }
 952
 953         /* unnamed socket from workers to the main daemon */
 954         if (socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, worker_watch) < 0) {
 955                 fprintf(stderr, "error getting socketpair\n");
 956                 err(udev, "error getting socketpair\n");
 957                 rc = 6;
 958                 goto exit;
 959         }
 960         pfd[FD_WORKER].fd = worker_watch[READ_END];
 961
 962         rules = udev_rules_new(udev, resolve_names);
 963         if (rules == NULL) {
 964                 err(udev, "error reading rules\n");
 965                 goto exit;
 966         }
 967
 968         udev_queue_export = udev_queue_export_new(udev);
 969         if (udev_queue_export == NULL) {
 970                 err(udev, "error creating queue file\n");
 971                 goto exit;
 972         }
 973
 974         if (daemonize) {
 975                 pid_t pid;
 976
 977                 pid = fork();
 978                 switch (pid) {
 979                 case 0:
 980                         break;
 981                 case -1:
 982                         err(udev, "fork of daemon failed: %m\n");
 983                         rc = 4;
 984                         goto exit;
 985                 default:
 986                         rc = 0;
 987                         goto exit;
 988                 }
 989         }
 990
 991         startup_log(udev);
 992
 993         /* redirect std{out,err} */
 994         if (!debug && !debug_trace) {
 995                 dup2(fd, STDIN_FILENO);
 996                 dup2(fd, STDOUT_FILENO);
 997                 dup2(fd, STDERR_FILENO);
 998         }
 999         if (fd > STDERR_FILENO)
1000                 close(fd);
1001
1002         /* set scheduling priority for the daemon */
1003         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1004
1005         chdir("/");
1006         umask(022);
1007         setsid();
1008
1009         /* OOM_DISABLE == -17 */
1010         fd = open("/proc/self/oom_adj", O_RDWR);
1011         if (fd < 0) {
1012                 err(udev, "error disabling OOM: %m\n");
1013         } else {
1014                 write(fd, "-17", 3);
1015                 close(fd);
1016         }
1017
1018         /* in trace mode run one event after the other */
1019         if (debug_trace) {
1020                 max_childs = 1;
1021         } else {
1022                 int memsize = mem_size_mb();
1023
1024                 if (memsize > 0)
1025                         max_childs = 128 + (memsize / 8);
1026                 else
1027                         max_childs = 128;
1028         }
1029
1030         /* possibly overwrite maximum limit of executed events */
1031         value = getenv("UDEVD_MAX_CHILDS");
1032         if (value)
1033                 max_childs = strtoul(value, NULL, 10);
1034         info(udev, "initialize max_childs to %u\n", max_childs);
1035
1036         udev_list_init(&event_list);
1037         udev_list_init(&worker_list);
1038
1039         while (!udev_exit) {
1040                 int fdcount;
1041                 int timeout;
1042
1043                 /* set timeout to kill idle workers */
1044                 if (udev_list_is_empty(&event_list) && childs > 2)
1045                         timeout = 3 * 1000;
1046                 else
1047                         timeout = -1;
1048                 /* wait for events */
1049                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1050                 if (fdcount < 0)
1051                         continue;
1052
1053                 /* timeout - kill idle workers */
1054                 if (fdcount == 0)
1055                         worker_kill(udev, 2);
1056
1057                 /* event has finished */
1058                 if (pfd[FD_WORKER].revents & POLLIN)
1059                         worker_returned();
1060
1061                 /* get kernel uevent */
1062                 if (pfd[FD_NETLINK].revents & POLLIN) {
1063                         struct udev_device *dev;
1064
1065                         dev = udev_monitor_receive_device(monitor);
1066                         if (dev != NULL)
1067                                 event_queue_insert(dev);
1068                         else
1069                                 udev_device_unref(dev);
1070                 }
1071
1072                 /* start new events */
1073                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1074                         events_start(udev);
1075
1076                 /* get signal */
1077                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1078                         struct signalfd_siginfo fdsi;
1079                         ssize_t size;
1080
1081                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1082                         if (size == sizeof(struct signalfd_siginfo))
1083                                 handle_signal(udev, fdsi.ssi_signo);
1084                 }
1085
1086                 /* device node and rules directory inotify watch */
1087                 if (pfd[FD_INOTIFY].revents & POLLIN)
1088                         handle_inotify(udev);
1089
1090                 /*
1091                  * get control message
1092                  *
1093                  * This needs to be after the inotify handling, to make sure,
1094                  * that the settle signal is send back after the possibly generated
1095                  * "change" events by the inotify device node watch.
1096                  */
1097                 if (pfd[FD_CONTROL].revents & POLLIN)
1098                         handle_ctrl_msg(udev_ctrl);
1099
1100                 /* rules changed, set by inotify or a HUP signal */
1101                 if (reload_config) {
1102                         struct udev_rules *rules_new;
1103
1104                         worker_kill(udev, 0);
1105                         rules_new = udev_rules_new(udev, resolve_names);
1106                         if (rules_new != NULL) {
1107                                 udev_rules_unref(rules);
1108                                 rules = rules_new;
1109                         }
1110                         reload_config = 0;
1111                 }
1112         }
1113
1114         udev_queue_export_cleanup(udev_queue_export);
1115         rc = 0;
1116 exit:
1117         udev_queue_export_unref(udev_queue_export);
1118         udev_rules_unref(rules);
1119         udev_ctrl_unref(udev_ctrl);
1120         if (pfd[FD_SIGNAL].fd >= 0)
1121                 close(pfd[FD_SIGNAL].fd);
1122         if (worker_watch[READ_END] >= 0)
1123                 close(worker_watch[READ_END]);
1124         if (worker_watch[WRITE_END] >= 0)
1125                 close(worker_watch[WRITE_END]);
1126         udev_monitor_unref(monitor);
1127         udev_selinux_exit(udev);
1128         udev_unref(udev);
1129         udev_log_close();
1130         return rc;
1131 }