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 #include <sys/utsname.h>
  45
  46 #include "udev.h"
  47
  48 #define UDEVD_PRIORITY                  -4
  49 #define UDEV_PRIORITY                   -2
  50
  51 static bool debug;
  52
  53 static void log_fn(struct udev *udev, int priority,
  54                    const char *file, int line, const char *fn,
  55                    const char *format, va_list args)
  56 {
  57         if (debug) {
  58                 char buf[1024];
  59                 struct timeval tv;
  60                 struct timezone tz;
  61
  62                 vsnprintf(buf, sizeof(buf), format, args);
  63                 gettimeofday(&tv, &tz);
  64                 fprintf(stderr, "%llu.%06u [%u] %s: %s",
  65                         (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
  66                         (int) getpid(), fn, buf);
  67         } else {
  68                 vsyslog(priority, format, args);
  69         }
  70 }
  71
  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 children;
  81 static int children_max;
  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), "remove") != 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         children--;
 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                         if (err == 0)
 296                                 failed = udev_event_execute_run(udev_event, &orig_sigmask);
 297
 298                         alarm(0);
 299
 300                         /* apply/restore inotify watch */
 301                         if (err == 0 && udev_event->inotify_watch) {
 302                                 udev_watch_begin(udev_event->udev, dev);
 303                                 udev_device_update_db(dev);
 304                         }
 305
 306                         /* send processed event back to libudev listeners */
 307                         udev_monitor_send_device(worker_monitor, NULL, dev);
 308
 309                         /* send udevd the result of the event execution */
 310                         if (err != 0)
 311                                 msg.exitcode = err;
 312                         else if (failed != 0)
 313                                 msg.exitcode = failed;
 314                         msg.pid = getpid();
 315                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 316
 317                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 318                         udev_event_unref(udev_event);
 319                         udev_device_unref(dev);
 320                         dev = NULL;
 321
 322                         /* wait for more device messages or signal from udevd */
 323                         while (!worker_exit) {
 324                                 int fdcount;
 325
 326                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 327                                 if (fdcount < 0)
 328                                         continue;
 329
 330                                 if (pmon.revents & POLLIN) {
 331                                         dev = udev_monitor_receive_device(worker_monitor);
 332                                         if (dev != NULL)
 333                                                 break;
 334                                 }
 335                         }
 336                 } while (dev != NULL);
 337
 338                 udev_monitor_unref(worker_monitor);
 339                 udev_log_close();
 340                 exit(0);
 341         }
 342         case -1:
 343                 udev_monitor_unref(worker_monitor);
 344                 event->state = EVENT_QUEUED;
 345                 free(worker);
 346                 err(event->udev, "fork of child failed: %m\n");
 347                 break;
 348         default:
 349                 /* close monitor, but keep address around */
 350                 udev_monitor_disconnect(worker_monitor);
 351                 worker->monitor = worker_monitor;
 352                 worker->pid = pid;
 353                 worker->state = WORKER_RUNNING;
 354                 worker->event = event;
 355                 event->state = EVENT_RUNNING;
 356                 udev_list_node_append(&worker->node, &worker_list);
 357                 children++;
 358                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 359                 break;
 360         }
 361 }
 362
 363 static void event_run(struct event *event, bool force)
 364 {
 365         struct udev_list_node *loop;
 366
 367         udev_list_node_foreach(loop, &worker_list) {
 368                 struct worker *worker = node_to_worker(loop);
 369                 ssize_t count;
 370
 371                 if (worker->state != WORKER_IDLE)
 372                         continue;
 373
 374                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 375                 if (count < 0) {
 376                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 377                         kill(worker->pid, SIGKILL);
 378                         worker->state = WORKER_KILLED;
 379                         continue;
 380                 }
 381                 worker_ref(worker);
 382                 worker->event = event;
 383                 worker->state = WORKER_RUNNING;
 384                 event->state = EVENT_RUNNING;
 385                 return;
 386         }
 387
 388         if (!force && children >= children_max) {
 389                 info(event->udev, "maximum number (%i) of children reached\n", children);
 390                 return;
 391         }
 392
 393         /* start new worker and pass initial device */
 394         worker_new(event);
 395 }
 396
 397 static void event_queue_insert(struct udev_device *dev)
 398 {
 399         struct event *event;
 400
 401         event = calloc(1, sizeof(struct event));
 402         if (event == NULL)
 403                 return;
 404
 405         event->udev = udev_device_get_udev(dev);
 406         event->dev = dev;
 407         event->seqnum = udev_device_get_seqnum(dev);
 408         event->devpath = udev_device_get_devpath(dev);
 409         event->devpath_len = strlen(event->devpath);
 410         event->devpath_old = udev_device_get_devpath_old(dev);
 411         event->devnum = udev_device_get_devnum(dev);
 412         event->is_block = (strcmp("block", udev_device_get_subsystem(dev)) == 0);
 413
 414         udev_queue_export_device_queued(udev_queue_export, dev);
 415         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 416              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 417
 418         event->state = EVENT_QUEUED;
 419         udev_list_node_append(&event->node, &event_list);
 420
 421         /* run all events with a timeout set immediately */
 422         if (udev_device_get_timeout(dev) > 0) {
 423                 event_run(event, true);
 424                 return;
 425         }
 426 }
 427
 428 static void worker_kill(struct udev *udev, int retain)
 429 {
 430         struct udev_list_node *loop;
 431         int max;
 432
 433         if (children <= retain)
 434                 return;
 435
 436         max = children - retain;
 437
 438         udev_list_node_foreach(loop, &worker_list) {
 439                 struct worker *worker = node_to_worker(loop);
 440
 441                 if (max-- <= 0)
 442                         break;
 443
 444                 if (worker->state == WORKER_KILLED)
 445                         continue;
 446
 447                 worker->state = WORKER_KILLED;
 448                 kill(worker->pid, SIGTERM);
 449         }
 450 }
 451
 452 /* lookup event for identical, parent, child device */
 453 static bool is_devpath_busy(struct event *event)
 454 {
 455         struct udev_list_node *loop;
 456         size_t common;
 457
 458         /* check if queue contains events we depend on */
 459         udev_list_node_foreach(loop, &event_list) {
 460                 struct event *loop_event = node_to_event(loop);
 461
 462                 /* we already found a later event, earlier can not block us, no need to check again */
 463                 if (loop_event->seqnum < event->delaying_seqnum)
 464                         continue;
 465
 466                 /* event we checked earlier still exists, no need to check again */
 467                 if (loop_event->seqnum == event->delaying_seqnum)
 468                         return true;
 469
 470                 /* found ourself, no later event can block us */
 471                 if (loop_event->seqnum >= event->seqnum)
 472                         break;
 473
 474                 /* check major/minor */
 475                 if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
 476                         return true;
 477
 478                 /* check our old name */
 479                 if (event->devpath_old != NULL && strcmp(loop_event->devpath, event->devpath_old) == 0) {
 480                         event->delaying_seqnum = loop_event->seqnum;
 481                         return true;
 482                 }
 483
 484                 /* compare devpath */
 485                 common = MIN(loop_event->devpath_len, event->devpath_len);
 486
 487                 /* one devpath is contained in the other? */
 488                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 489                         continue;
 490
 491                 /* identical device event found */
 492                 if (loop_event->devpath_len == event->devpath_len) {
 493                         event->delaying_seqnum = loop_event->seqnum;
 494                         return true;
 495                 }
 496
 497                 /* parent device event found */
 498                 if (event->devpath[common] == '/') {
 499                         event->delaying_seqnum = loop_event->seqnum;
 500                         return true;
 501                 }
 502
 503                 /* child device event found */
 504                 if (loop_event->devpath[common] == '/') {
 505                         event->delaying_seqnum = loop_event->seqnum;
 506                         return true;
 507                 }
 508
 509                 /* no matching device */
 510                 continue;
 511         }
 512
 513         return false;
 514 }
 515
 516 static void events_start(struct udev *udev)
 517 {
 518         struct udev_list_node *loop;
 519
 520         udev_list_node_foreach(loop, &event_list) {
 521                 struct event *event = node_to_event(loop);
 522
 523                 if (event->state != EVENT_QUEUED)
 524                         continue;
 525
 526                 /* do not start event if parent or child event is still running */
 527                 if (is_devpath_busy(event)) {
 528                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 529                         continue;
 530                 }
 531
 532                 event_run(event, false);
 533         }
 534 }
 535
 536 static void worker_returned(void)
 537 {
 538         for (;;) {
 539                 struct worker_message msg;
 540                 ssize_t size;
 541                 struct udev_list_node *loop;
 542
 543                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 544                 if (size != sizeof(struct worker_message))
 545                         break;
 546
 547                 /* lookup worker who sent the signal */
 548                 udev_list_node_foreach(loop, &worker_list) {
 549                         struct worker *worker = node_to_worker(loop);
 550
 551                         if (worker->pid != msg.pid)
 552                                 continue;
 553
 554                         /* worker returned */
 555                         worker->event->exitcode = msg.exitcode;
 556                         event_queue_delete(worker->event);
 557                         worker->event = NULL;
 558                         if (worker->state != WORKER_KILLED)
 559                                 worker->state = WORKER_IDLE;
 560                         worker_unref(worker);
 561                         break;
 562                 }
 563         }
 564 }
 565
 566 /* receive the udevd message from userspace */
 567 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 568 {
 569         struct udev *udev = udev_ctrl_get_udev(uctrl);
 570         struct udev_ctrl_msg *ctrl_msg;
 571         const char *str;
 572         int i;
 573
 574         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 575         if (ctrl_msg == NULL)
 576                 return;
 577
 578         i = udev_ctrl_get_set_log_level(ctrl_msg);
 579         if (i >= 0) {
 580                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 581                 udev_set_log_priority(udev, i);
 582                 worker_kill(udev, 0);
 583         }
 584
 585         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 586                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 587                 stop_exec_queue = true;
 588         }
 589
 590         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 591                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 592                 stop_exec_queue = false;
 593         }
 594
 595         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 596                 info(udev, "udevd message (RELOAD_RULES) received\n");
 597                 reload_config = true;
 598         }
 599
 600         str = udev_ctrl_get_set_env(ctrl_msg);
 601         if (str != NULL) {
 602                 char *key;
 603
 604                 key = strdup(str);
 605                 if (key != NULL) {
 606                         char *val;
 607
 608                         val = strchr(key, '=');
 609                         if (val != NULL) {
 610                                 val[0] = '\0';
 611                                 val = &val[1];
 612                                 if (val[0] == '\0') {
 613                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 614                                         udev_add_property(udev, key, NULL);
 615                                 } else {
 616                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 617                                         udev_add_property(udev, key, val);
 618                                 }
 619                         } else {
 620                                 err(udev, "wrong key format '%s'\n", key);
 621                         }
 622                         free(key);
 623                 }
 624                 worker_kill(udev, 0);
 625         }
 626
 627         i = udev_ctrl_get_set_children_max(ctrl_msg);
 628         if (i >= 0) {
 629                 info(udev, "udevd message (SET_MAX_CHILDREN) received, children_max=%i\n", i);
 630                 children_max = i;
 631         }
 632
 633         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 634         if (settle_pid > 0) {
 635                 info(udev, "udevd message (SETTLE) received\n");
 636                 kill(settle_pid, SIGUSR1);
 637                 settle_pid = 0;
 638         }
 639         udev_ctrl_msg_unref(ctrl_msg);
 640 }
 641
 642 /* read inotify messages */
 643 static int handle_inotify(struct udev *udev)
 644 {
 645         int nbytes, pos;
 646         char *buf;
 647         struct inotify_event *ev;
 648
 649         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 650                 return 0;
 651
 652         buf = malloc(nbytes);
 653         if (buf == NULL) {
 654                 err(udev, "error getting buffer for inotify\n");
 655                 return -1;
 656         }
 657
 658         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 659
 660         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 661                 struct udev_device *dev;
 662
 663                 ev = (struct inotify_event *)(buf + pos);
 664                 if (ev->len) {
 665                         const char *s;
 666
 667                         info(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 668                         s = strstr(ev->name, ".rules");
 669                         if (s == NULL)
 670                                 continue;
 671                         if (strlen(s) != strlen(".rules"))
 672                                 continue;
 673                         reload_config = true;
 674                         continue;
 675                 }
 676
 677                 dev = udev_watch_lookup(udev, ev->wd);
 678                 if (dev != NULL) {
 679                         info(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 680                         if (ev->mask & IN_CLOSE_WRITE) {
 681                                 char filename[UTIL_PATH_SIZE];
 682                                 int fd;
 683
 684                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 685                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 686                                 fd = open(filename, O_WRONLY);
 687                                 if (fd < 0 || write(fd, "change", 6) < 0)
 688                                         info(udev, "error writing uevent: %m\n");
 689                                 close(fd);
 690                         }
 691                         if (ev->mask & IN_IGNORED)
 692                                 udev_watch_end(udev, dev);
 693
 694                         udev_device_unref(dev);
 695                 }
 696
 697         }
 698
 699         free(buf);
 700         return 0;
 701 }
 702
 703 static void handle_signal(struct udev *udev, int signo)
 704 {
 705         switch (signo) {
 706         case SIGINT:
 707         case SIGTERM:
 708                 udev_exit = true;
 709                 break;
 710         case SIGCHLD:
 711                 for (;;) {
 712                         pid_t pid;
 713                         int status;
 714                         struct udev_list_node *loop, *tmp;
 715
 716                         pid = waitpid(-1, &status, WNOHANG);
 717                         if (pid <= 0)
 718                                 break;
 719
 720                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 721                                 struct worker *worker = node_to_worker(loop);
 722
 723                                 if (worker->pid != pid)
 724                                         continue;
 725
 726                                 info(udev, "worker [%u] exit\n", pid);
 727                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 728                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 729                                         if (worker->event != NULL) {
 730                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 731                                                 worker->event->exitcode = -32;
 732                                                 event_queue_delete(worker->event);
 733                                                 /* drop reference from running event */
 734                                                 worker_unref(worker);
 735                                         }
 736                                 }
 737                                 worker_unref(worker);
 738                                 break;
 739                         }
 740                 }
 741                 break;
 742         case SIGHUP:
 743                 reload_config = true;
 744                 break;
 745         }
 746 }
 747
 748 static void static_dev_create_from_modules(struct udev *udev)
 749 {
 750         struct utsname kernel;
 751         char modules[UTIL_PATH_SIZE];
 752         char buf[4096];
 753         FILE *f;
 754
 755         uname(&kernel);
 756         util_strscpyl(modules, sizeof(modules), "/lib/modules/", kernel.release, "/modules.devname", NULL);
 757         f = fopen(modules, "r");
 758         if (f == NULL)
 759                 return;
 760
 761         while (fgets(buf, sizeof(buf), f) != NULL) {
 762                 char *s;
 763                 const char *modname;
 764                 const char *devname;
 765                 const char *devno;
 766                 int maj, min;
 767                 char type;
 768                 mode_t mode;
 769                 char filename[UTIL_PATH_SIZE];
 770
 771                 if (buf[0] == '#')
 772                         continue;
 773
 774                 modname = buf;
 775                 s = strchr(modname, ' ');
 776                 if (s == NULL)
 777                         continue;
 778                 s[0] = '\0';
 779
 780                 devname = &s[1];
 781                 s = strchr(devname, ' ');
 782                 if (s == NULL)
 783                         continue;
 784                 s[0] = '\0';
 785
 786                 devno = &s[1];
 787                 s = strchr(devno, ' ');
 788                 if (s == NULL)
 789                         s = strchr(devno, '\n');
 790                 if (s != NULL)
 791                         s[0] = '\0';
 792                 if (sscanf(devno, "%c%u:%u", &type, &maj, &min) != 3)
 793                         continue;
 794
 795                 if (type == 'c')
 796                         mode = 0600 | S_IFCHR;
 797                 else if (type == 'b')
 798                         mode = 0600 | S_IFBLK;
 799                 else
 800                         continue;
 801
 802                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/", devname, NULL);
 803                 util_create_path(udev, filename);
 804                 udev_selinux_setfscreatecon(udev, filename, mode);
 805                 info(udev, "mknod '%s' %c%u:%u\n", filename, type, maj, min);
 806                 if (mknod(filename, mode, makedev(maj, min)) < 0 && errno == EEXIST)
 807                         utimensat(AT_FDCWD, filename, NULL, 0);
 808                 udev_selinux_resetfscreatecon(udev);
 809         }
 810
 811         fclose(f);
 812 }
 813
 814 static int copy_dir(struct udev *udev, DIR *dir_from, DIR *dir_to, int maxdepth)
 815 {
 816         struct dirent *dent;
 817
 818         for (dent = readdir(dir_from); dent != NULL; dent = readdir(dir_from)) {
 819                 struct stat stats;
 820
 821                 if (dent->d_name[0] == '.')
 822                         continue;
 823                 if (fstatat(dirfd(dir_from), dent->d_name, &stats, AT_SYMLINK_NOFOLLOW) != 0)
 824                         continue;
 825
 826                 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
 827                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, stats.st_mode & 0777);
 828                         if (mknodat(dirfd(dir_to), dent->d_name, stats.st_mode, stats.st_rdev) == 0) {
 829                                 fchmodat(dirfd(dir_to), dent->d_name, stats.st_mode & 0777, 0);
 830                                 fchownat(dirfd(dir_to), dent->d_name, stats.st_uid, stats.st_gid, 0);
 831                         } else {
 832                                 utimensat(dirfd(dir_to), dent->d_name, NULL, 0);
 833                         }
 834                         udev_selinux_resetfscreatecon(udev);
 835                 } else if (S_ISLNK(stats.st_mode)) {
 836                         char target[UTIL_PATH_SIZE];
 837                         ssize_t len;
 838
 839                         len = readlinkat(dirfd(dir_from), dent->d_name, target, sizeof(target));
 840                         if (len <= 0 || len == (ssize_t)sizeof(target))
 841                                 continue;
 842                         target[len] = '\0';
 843                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFLNK);
 844                         if (symlinkat(target, dirfd(dir_to), dent->d_name) < 0 && errno == EEXIST)
 845                                 utimensat(dirfd(dir_to), dent->d_name, NULL, AT_SYMLINK_NOFOLLOW);
 846                         udev_selinux_resetfscreatecon(udev);
 847                 } else if (S_ISDIR(stats.st_mode)) {
 848                         DIR *dir2_from, *dir2_to;
 849
 850                         if (maxdepth == 0)
 851                                 continue;
 852
 853                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFDIR|0755);
 854                         mkdirat(dirfd(dir_to), dent->d_name, 0755);
 855                         udev_selinux_resetfscreatecon(udev);
 856
 857                         dir2_to = fdopendir(openat(dirfd(dir_to), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 858                         if (dir2_to == NULL)
 859                                 continue;
 860
 861                         dir2_from = fdopendir(openat(dirfd(dir_from), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 862                         if (dir2_from == NULL) {
 863                                 closedir(dir2_to);
 864                                 continue;
 865                         }
 866
 867                         copy_dir(udev, dir2_from, dir2_to, maxdepth-1);
 868
 869                         closedir(dir2_to);
 870                         closedir(dir2_from);
 871                 }
 872         }
 873
 874         return 0;
 875 }
 876
 877 static void static_dev_create_links(struct udev *udev, DIR *dir)
 878 {
 879         struct stdlinks {
 880                 const char *link;
 881                 const char *target;
 882         };
 883         static const struct stdlinks stdlinks[] = {
 884                 { "core", "/proc/kcore" },
 885                 { "fd", "/proc/self/fd" },
 886                 { "stdin", "/proc/self/fd/0" },
 887                 { "stdout", "/proc/self/fd/1" },
 888                 { "stderr", "/proc/self/fd/2" },
 889         };
 890         unsigned int i;
 891
 892         for (i = 0; i < ARRAY_SIZE(stdlinks); i++) {
 893                 udev_selinux_setfscreateconat(udev, dirfd(dir), stdlinks[i].link, S_IFLNK);
 894                 if (symlinkat(stdlinks[i].target, dirfd(dir), stdlinks[i].link) < 0 && errno == EEXIST)
 895                         utimensat(dirfd(dir), stdlinks[i].link, NULL, AT_SYMLINK_NOFOLLOW);
 896                 udev_selinux_resetfscreatecon(udev);
 897         }
 898 }
 899
 900 static void static_dev_create_from_devices(struct udev *udev, DIR *dir)
 901 {
 902         DIR *dir_from;
 903
 904         dir_from = opendir(LIBEXECDIR "/devices");
 905         if (dir_from == NULL)
 906                 return;
 907         copy_dir(udev, dir_from, dir, 8);
 908         closedir(dir_from);
 909 }
 910
 911 static void static_dev_create(struct udev *udev)
 912 {
 913         DIR *dir;
 914
 915         dir = opendir(udev_get_dev_path(udev));
 916         if (dir == NULL)
 917                 return;
 918
 919         static_dev_create_links(udev, dir);
 920         static_dev_create_from_devices(udev, dir);
 921
 922         closedir(dir);
 923 }
 924
 925 static int mem_size_mb(void)
 926 {
 927         FILE *f;
 928         char buf[4096];
 929         long int memsize = -1;
 930
 931         f = fopen("/proc/meminfo", "r");
 932         if (f == NULL)
 933                 return -1;
 934
 935         while (fgets(buf, sizeof(buf), f) != NULL) {
 936                 long int value;
 937
 938                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 939                         memsize = value / 1024;
 940                         break;
 941                 }
 942         }
 943
 944         fclose(f);
 945         return memsize;
 946 }
 947
 948 int main(int argc, char *argv[])
 949 {
 950         struct udev *udev;
 951         int fd;
 952         FILE *f;
 953         sigset_t mask;
 954         int daemonize = false;
 955         int resolve_names = 1;
 956         static const struct option options[] = {
 957                 { "daemon", no_argument, NULL, 'd' },
 958                 { "debug", no_argument, NULL, 'D' },
 959                 { "children-max", required_argument, NULL, 'c' },
 960                 { "resolve-names", required_argument, NULL, 'N' },
 961                 { "help", no_argument, NULL, 'h' },
 962                 { "version", no_argument, NULL, 'V' },
 963                 {}
 964         };
 965         int rc = 1;
 966
 967         udev = udev_new();
 968         if (udev == NULL)
 969                 goto exit;
 970
 971         udev_log_init("udevd");
 972         udev_set_log_fn(udev, log_fn);
 973         info(udev, "version %s\n", VERSION);
 974         udev_selinux_init(udev);
 975
 976         for (;;) {
 977                 int option;
 978
 979                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 980                 if (option == -1)
 981                         break;
 982
 983                 switch (option) {
 984                 case 'd':
 985                         daemonize = true;
 986                         break;
 987                 case 'c':
 988                         children_max = strtoul(optarg, NULL, 10);
 989                         break;
 990                 case 'D':
 991                         debug = true;
 992                         if (udev_get_log_priority(udev) < LOG_INFO)
 993                                 udev_set_log_priority(udev, LOG_INFO);
 994                         break;
 995                 case 'N':
 996                         if (strcmp (optarg, "early") == 0) {
 997                                 resolve_names = 1;
 998                         } else if (strcmp (optarg, "late") == 0) {
 999                                 resolve_names = 0;
1000                         } else if (strcmp (optarg, "never") == 0) {
1001                                 resolve_names = -1;
1002                         } else {
1003                                 fprintf(stderr, "resolve-names must be early, late or never\n");
1004                                 err(udev, "resolve-names must be early, late or never\n");
1005                                 goto exit;
1006                         }
1007                         break;
1008                 case 'h':
1009                         printf("Usage: udevd [--help] [--daemon] [--children-max] [--debug] "
1010                                "[--resolve-names=early|late|never] [--version]\n");
1011                         goto exit;
1012                 case 'V':
1013                         printf("%s\n", VERSION);
1014                         goto exit;
1015                 default:
1016                         goto exit;
1017                 }
1018         }
1019
1020         if (getuid() != 0) {
1021                 fprintf(stderr, "root privileges required\n");
1022                 err(udev, "root privileges required\n");
1023                 goto exit;
1024         }
1025
1026         /* make sure std{in,out,err} fd's are in a sane state */
1027         fd = open("/dev/null", O_RDWR);
1028         if (fd < 0) {
1029                 fprintf(stderr, "cannot open /dev/null\n");
1030                 err(udev, "cannot open /dev/null\n");
1031         }
1032         if (write(STDOUT_FILENO, 0, 0) < 0)
1033                 dup2(fd, STDOUT_FILENO);
1034         if (write(STDERR_FILENO, 0, 0) < 0)
1035                 dup2(fd, STDERR_FILENO);
1036
1037         /* init control socket, bind() ensures, that only one udevd instance is running */
1038         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
1039         if (udev_ctrl == NULL) {
1040                 fprintf(stderr, "error initializing control socket");
1041                 err(udev, "error initializing udevd socket");
1042                 rc = 1;
1043                 goto exit;
1044         }
1045         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
1046                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
1047                 err(udev, "error binding control socket, seems udevd is already running\n");
1048                 rc = 1;
1049                 goto exit;
1050         }
1051         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
1052
1053         monitor = udev_monitor_new_from_netlink(udev, "kernel");
1054         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
1055                 fprintf(stderr, "error initializing netlink socket\n");
1056                 err(udev, "error initializing netlink socket\n");
1057                 rc = 3;
1058                 goto exit;
1059         }
1060         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
1061         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
1062
1063         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
1064         if (pfd[FD_INOTIFY].fd < 0) {
1065                 fprintf(stderr, "error initializing inotify\n");
1066                 err(udev, "error initializing inotify\n");
1067                 rc = 4;
1068                 goto exit;
1069         }
1070
1071         if (udev_get_rules_path(udev) != NULL) {
1072                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
1073                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1074         } else {
1075                 char filename[UTIL_PATH_SIZE];
1076                 struct stat statbuf;
1077
1078                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
1079                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1080                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
1081                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1082
1083                 /* watch dynamic rules directory */
1084                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
1085                 if (stat(filename, &statbuf) != 0) {
1086                         util_create_path(udev, filename);
1087                         udev_selinux_setfscreatecon(udev, filename, S_IFDIR|0755);
1088                         mkdir(filename, 0755);
1089                         udev_selinux_resetfscreatecon(udev);
1090                 }
1091                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
1092                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1093         }
1094         udev_watch_restore(udev);
1095
1096         /* block and listen to all signals on signalfd */
1097         sigfillset(&mask);
1098         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
1099         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
1100         if (pfd[FD_SIGNAL].fd < 0) {
1101                 fprintf(stderr, "error getting signalfd\n");
1102                 err(udev, "error getting signalfd\n");
1103                 rc = 5;
1104                 goto exit;
1105         }
1106
1107         /* unnamed socket from workers to the main daemon */
1108         if (socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, worker_watch) < 0) {
1109                 fprintf(stderr, "error getting socketpair\n");
1110                 err(udev, "error getting socketpair\n");
1111                 rc = 6;
1112                 goto exit;
1113         }
1114         pfd[FD_WORKER].fd = worker_watch[READ_END];
1115
1116         rules = udev_rules_new(udev, resolve_names);
1117         if (rules == NULL) {
1118                 err(udev, "error reading rules\n");
1119                 goto exit;
1120         }
1121
1122         udev_queue_export = udev_queue_export_new(udev);
1123         if (udev_queue_export == NULL) {
1124                 err(udev, "error creating queue file\n");
1125                 goto exit;
1126         }
1127
1128         if (daemonize) {
1129                 pid_t pid;
1130
1131                 pid = fork();
1132                 switch (pid) {
1133                 case 0:
1134                         break;
1135                 case -1:
1136                         err(udev, "fork of daemon failed: %m\n");
1137                         rc = 4;
1138                         goto exit;
1139                 default:
1140                         rc = 0;
1141                         goto exit;
1142                 }
1143         }
1144
1145         f = fopen("/dev/kmsg", "w");
1146         if (f != NULL) {
1147                 fprintf(f, "<6>udev: starting version " VERSION "\n");
1148                 fclose(f);
1149         }
1150
1151         /* redirect std{out,err} */
1152         if (!debug) {
1153                 dup2(fd, STDIN_FILENO);
1154                 dup2(fd, STDOUT_FILENO);
1155                 dup2(fd, STDERR_FILENO);
1156         }
1157         if (fd > STDERR_FILENO)
1158                 close(fd);
1159
1160         /* set scheduling priority for the daemon */
1161         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1162
1163         chdir("/");
1164         umask(022);
1165         setsid();
1166
1167         /* OOM_DISABLE == -17 */
1168         fd = open("/proc/self/oom_adj", O_RDWR);
1169         if (fd < 0) {
1170                 err(udev, "error disabling OOM: %m\n");
1171         } else {
1172                 write(fd, "-17", 3);
1173                 close(fd);
1174         }
1175
1176         if (children_max <= 0) {
1177                 const char *value = getenv("UDEVD_CHILDREN_MAX");
1178
1179                 if (value) {
1180                         children_max = strtoul(value, NULL, 10);
1181                 } else {
1182                         int memsize = mem_size_mb();
1183
1184                         /* set value depending on the amount of RAM */
1185                         if (memsize > 0)
1186                                 children_max = 128 + (memsize / 8);
1187                         else
1188                                 children_max = 128;
1189                 }
1190         }
1191         info(udev, "set children_max to %u\n", children_max);
1192
1193         static_dev_create(udev);
1194         static_dev_create_from_modules(udev);
1195         udev_rules_apply_static_dev_perms(rules);
1196
1197         udev_list_init(&event_list);
1198         udev_list_init(&worker_list);
1199
1200         while (!udev_exit) {
1201                 int fdcount;
1202                 int timeout;
1203
1204                 /* set timeout to kill idle workers */
1205                 if (udev_list_is_empty(&event_list) && children > 2)
1206                         timeout = 3 * 1000;
1207                 else
1208                         timeout = -1;
1209                 /* wait for events */
1210                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1211                 if (fdcount < 0)
1212                         continue;
1213
1214                 /* timeout - kill idle workers */
1215                 if (fdcount == 0)
1216                         worker_kill(udev, 2);
1217
1218                 /* event has finished */
1219                 if (pfd[FD_WORKER].revents & POLLIN)
1220                         worker_returned();
1221
1222                 /* get kernel uevent */
1223                 if (pfd[FD_NETLINK].revents & POLLIN) {
1224                         struct udev_device *dev;
1225
1226                         dev = udev_monitor_receive_device(monitor);
1227                         if (dev != NULL)
1228                                 event_queue_insert(dev);
1229                         else
1230                                 udev_device_unref(dev);
1231                 }
1232
1233                 /* start new events */
1234                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1235                         events_start(udev);
1236
1237                 /* get signal */
1238                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1239                         struct signalfd_siginfo fdsi;
1240                         ssize_t size;
1241
1242                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1243                         if (size == sizeof(struct signalfd_siginfo))
1244                                 handle_signal(udev, fdsi.ssi_signo);
1245                 }
1246
1247                 /* device node and rules directory inotify watch */
1248                 if (pfd[FD_INOTIFY].revents & POLLIN)
1249                         handle_inotify(udev);
1250
1251                 /*
1252                  * get control message
1253                  *
1254                  * This needs to be after the inotify handling, to make sure,
1255                  * that the settle signal is send back after the possibly generated
1256                  * "change" events by the inotify device node watch.
1257                  */
1258                 if (pfd[FD_CONTROL].revents & POLLIN)
1259                         handle_ctrl_msg(udev_ctrl);
1260
1261                 /* rules changed, set by inotify or a HUP signal */
1262                 if (reload_config) {
1263                         struct udev_rules *rules_new;
1264
1265                         worker_kill(udev, 0);
1266                         rules_new = udev_rules_new(udev, resolve_names);
1267                         if (rules_new != NULL) {
1268                                 udev_rules_unref(rules);
1269                                 rules = rules_new;
1270                         }
1271                         reload_config = 0;
1272                 }
1273         }
1274
1275         udev_queue_export_cleanup(udev_queue_export);
1276         rc = 0;
1277 exit:
1278         udev_queue_export_unref(udev_queue_export);
1279         udev_rules_unref(rules);
1280         udev_ctrl_unref(udev_ctrl);
1281         if (pfd[FD_SIGNAL].fd >= 0)
1282                 close(pfd[FD_SIGNAL].fd);
1283         if (worker_watch[READ_END] >= 0)
1284                 close(worker_watch[READ_END]);
1285         if (worker_watch[WRITE_END] >= 0)
1286                 close(worker_watch[WRITE_END]);
1287         udev_monitor_unref(monitor);
1288         udev_selinux_exit(udev);
1289         udev_unref(udev);
1290         udev_log_close();
1291         return rc;
1292 }