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 bool debug_trace;
  73 static struct udev_rules *rules;
  74 static struct udev_queue_export *udev_queue_export;
  75 static struct udev_ctrl *udev_ctrl;
  76 static struct udev_monitor *monitor;
  77 static int worker_watch[2];
  78 static pid_t settle_pid;
  79 static bool stop_exec_queue;
  80 static bool reload_config;
  81 static int max_childs;
  82 static int childs;
  83 static sigset_t orig_sigmask;
  84 static struct udev_list_node event_list;
  85 static struct udev_list_node worker_list;
  86 static bool udev_exit;
  87 static volatile sig_atomic_t worker_exit;
  88
  89 enum poll_fd {
  90         FD_CONTROL,
  91         FD_NETLINK,
  92         FD_INOTIFY,
  93         FD_SIGNAL,
  94         FD_WORKER,
  95 };
  96
  97 static struct pollfd pfd[] = {
  98         [FD_NETLINK] = { .events = POLLIN },
  99         [FD_WORKER] =  { .events = POLLIN },
 100         [FD_SIGNAL] =  { .events = POLLIN },
 101         [FD_INOTIFY] = { .events = POLLIN },
 102         [FD_CONTROL] = { .events = POLLIN },
 103 };
 104
 105 enum event_state {
 106         EVENT_UNDEF,
 107         EVENT_QUEUED,
 108         EVENT_RUNNING,
 109 };
 110
 111 struct event {
 112         struct udev_list_node node;
 113         struct udev *udev;
 114         struct udev_device *dev;
 115         enum event_state state;
 116         int exitcode;
 117         unsigned long long int delaying_seqnum;
 118         unsigned long long int seqnum;
 119         const char *devpath;
 120         size_t devpath_len;
 121         const char *devpath_old;
 122         dev_t devnum;
 123         bool is_block;
 124 };
 125
 126 static struct event *node_to_event(struct udev_list_node *node)
 127 {
 128         char *event;
 129
 130         event = (char *)node;
 131         event -= offsetof(struct event, node);
 132         return (struct event *)event;
 133 }
 134
 135 enum worker_state {
 136         WORKER_UNDEF,
 137         WORKER_RUNNING,
 138         WORKER_IDLE,
 139         WORKER_KILLED,
 140 };
 141
 142 struct worker {
 143         struct udev_list_node node;
 144         struct udev *udev;
 145         int refcount;
 146         pid_t pid;
 147         struct udev_monitor *monitor;
 148         enum worker_state state;
 149         struct event *event;
 150 };
 151
 152 /* passed from worker to main process */
 153 struct worker_message {
 154         pid_t pid;
 155         int exitcode;
 156 };
 157
 158 static struct worker *node_to_worker(struct udev_list_node *node)
 159 {
 160         char *worker;
 161
 162         worker = (char *)node;
 163         worker -= offsetof(struct worker, node);
 164         return (struct worker *)worker;
 165 }
 166
 167 static void event_queue_delete(struct event *event)
 168 {
 169         udev_list_node_remove(&event->node);
 170
 171         /* mark as failed, if "add" event returns non-zero */
 172         if (event->exitcode != 0 && strcmp(udev_device_get_action(event->dev), "remove") != 0)
 173                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 174         else
 175                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 176
 177         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 178         udev_device_unref(event->dev);
 179         free(event);
 180 }
 181
 182 static void event_sig_handler(int signum)
 183 {
 184         switch (signum) {
 185         case SIGALRM:
 186                 _exit(1);
 187                 break;
 188         case SIGTERM:
 189                 worker_exit = true;
 190                 break;
 191         }
 192 }
 193
 194 static struct worker *worker_ref(struct worker *worker)
 195 {
 196         worker->refcount++;
 197         return worker;
 198 }
 199
 200 static void worker_unref(struct worker *worker)
 201 {
 202         worker->refcount--;
 203         if (worker->refcount > 0)
 204                 return;
 205
 206         udev_list_node_remove(&worker->node);
 207         udev_monitor_unref(worker->monitor);
 208         childs--;
 209         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 210         free(worker);
 211 }
 212
 213 static void worker_new(struct event *event)
 214 {
 215         struct worker *worker;
 216         struct udev_monitor *worker_monitor;
 217         pid_t pid;
 218         struct sigaction act;
 219
 220         /* listen for new events */
 221         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 222         if (worker_monitor == NULL)
 223                 return;
 224         /* allow the main daemon netlink address to send devices to the worker */
 225         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 226         udev_monitor_enable_receiving(worker_monitor);
 227
 228         worker = calloc(1, sizeof(struct worker));
 229         if (worker == NULL)
 230                 return;
 231         /* worker + event reference */
 232         worker->refcount = 2;
 233         worker->udev = event->udev;
 234
 235         pid = fork();
 236         switch (pid) {
 237         case 0: {
 238                 sigset_t sigmask;
 239                 struct udev_device *dev;
 240                 struct pollfd pmon = {
 241                         .fd = udev_monitor_get_fd(worker_monitor),
 242                         .events = POLLIN,
 243                 };
 244
 245                 udev_queue_export_unref(udev_queue_export);
 246                 udev_monitor_unref(monitor);
 247                 udev_ctrl_unref(udev_ctrl);
 248                 close(pfd[FD_SIGNAL].fd);
 249                 close(worker_watch[READ_END]);
 250                 udev_log_close();
 251                 udev_log_init("udevd-work");
 252                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 253
 254                 /* set signal handlers */
 255                 memset(&act, 0x00, sizeof(act));
 256                 act.sa_handler = event_sig_handler;
 257                 sigemptyset (&act.sa_mask);
 258                 act.sa_flags = 0;
 259                 sigaction(SIGTERM, &act, NULL);
 260                 sigaction(SIGALRM, &act, NULL);
 261
 262                 /* unblock SIGALRM */
 263                 sigfillset(&sigmask);
 264                 sigdelset(&sigmask, SIGALRM);
 265                 sigprocmask(SIG_SETMASK, &sigmask, NULL);
 266                 /* SIGTERM is unblocked in ppoll() */
 267                 sigdelset(&sigmask, SIGTERM);
 268
 269                 /* request TERM signal if parent exits */
 270                 prctl(PR_SET_PDEATHSIG, SIGTERM);
 271
 272                 /* initial device */
 273                 dev = event->dev;
 274
 275                 do {
 276                         struct udev_event *udev_event;
 277                         struct worker_message msg = {};
 278                         int err;
 279                         int failed = 0;
 280
 281                         info(event->udev, "seq %llu running\n", udev_device_get_seqnum(dev));
 282                         udev_event = udev_event_new(dev);
 283                         if (udev_event == NULL)
 284                                 _exit(3);
 285
 286                         /* set timeout to prevent hanging processes */
 287                         alarm(UDEV_EVENT_TIMEOUT);
 288
 289                         /* apply rules, create node, symlinks */
 290                         err = udev_event_execute_rules(udev_event, rules);
 291
 292                         /* rules may change/disable the timeout */
 293                         if (udev_device_get_event_timeout(dev) >= 0)
 294                                 alarm(udev_device_get_event_timeout(dev));
 295
 296                         if (err == 0)
 297                                 failed = udev_event_execute_run(udev_event, &orig_sigmask);
 298
 299                         alarm(0);
 300
 301                         /* apply/restore inotify watch */
 302                         if (err == 0 && udev_event->inotify_watch) {
 303                                 udev_watch_begin(udev_event->udev, dev);
 304                                 udev_device_update_db(dev);
 305                         }
 306
 307                         /* send processed event back to libudev listeners */
 308                         udev_monitor_send_device(worker_monitor, NULL, dev);
 309
 310                         /* send udevd the result of the event execution */
 311                         if (err != 0)
 312                                 msg.exitcode = err;
 313                         else if (failed != 0)
 314                                 msg.exitcode = failed;
 315                         msg.pid = getpid();
 316                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 317
 318                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 319                         udev_event_unref(udev_event);
 320                         udev_device_unref(dev);
 321                         dev = NULL;
 322
 323                         /* wait for more device messages or signal from udevd */
 324                         while (!worker_exit) {
 325                                 int fdcount;
 326
 327                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 328                                 if (fdcount < 0)
 329                                         continue;
 330
 331                                 if (pmon.revents & POLLIN) {
 332                                         dev = udev_monitor_receive_device(worker_monitor);
 333                                         if (dev != NULL)
 334                                                 break;
 335                                 }
 336                         }
 337                 } while (dev != NULL);
 338
 339                 udev_monitor_unref(worker_monitor);
 340                 udev_log_close();
 341                 exit(0);
 342         }
 343         case -1:
 344                 udev_monitor_unref(worker_monitor);
 345                 event->state = EVENT_QUEUED;
 346                 free(worker);
 347                 err(event->udev, "fork of child failed: %m\n");
 348                 break;
 349         default:
 350                 /* close monitor, but keep address around */
 351                 udev_monitor_disconnect(worker_monitor);
 352                 worker->monitor = worker_monitor;
 353                 worker->pid = pid;
 354                 worker->state = WORKER_RUNNING;
 355                 worker->event = event;
 356                 event->state = EVENT_RUNNING;
 357                 udev_list_node_append(&worker->node, &worker_list);
 358                 childs++;
 359                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 360                 break;
 361         }
 362 }
 363
 364 static void event_run(struct event *event, bool force)
 365 {
 366         struct udev_list_node *loop;
 367
 368         udev_list_node_foreach(loop, &worker_list) {
 369                 struct worker *worker = node_to_worker(loop);
 370                 ssize_t count;
 371
 372                 if (worker->state != WORKER_IDLE)
 373                         continue;
 374
 375                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 376                 if (count < 0) {
 377                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 378                         kill(worker->pid, SIGKILL);
 379                         worker->state = WORKER_KILLED;
 380                         continue;
 381                 }
 382                 worker_ref(worker);
 383                 worker->event = event;
 384                 worker->state = WORKER_RUNNING;
 385                 event->state = EVENT_RUNNING;
 386                 return;
 387         }
 388
 389         if (!force && childs >= max_childs) {
 390                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 391                 return;
 392         }
 393
 394         /* start new worker and pass initial device */
 395         worker_new(event);
 396 }
 397
 398 static void event_queue_insert(struct udev_device *dev)
 399 {
 400         struct event *event;
 401
 402         event = calloc(1, sizeof(struct event));
 403         if (event == NULL)
 404                 return;
 405
 406         event->udev = udev_device_get_udev(dev);
 407         event->dev = dev;
 408         event->seqnum = udev_device_get_seqnum(dev);
 409         event->devpath = udev_device_get_devpath(dev);
 410         event->devpath_len = strlen(event->devpath);
 411         event->devpath_old = udev_device_get_devpath_old(dev);
 412         event->devnum = udev_device_get_devnum(dev);
 413         event->is_block = (strcmp("block", udev_device_get_subsystem(dev)) == 0);
 414
 415         udev_queue_export_device_queued(udev_queue_export, dev);
 416         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 417              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 418
 419         event->state = EVENT_QUEUED;
 420         udev_list_node_append(&event->node, &event_list);
 421
 422         /* run all events with a timeout set immediately */
 423         if (udev_device_get_timeout(dev) > 0) {
 424                 event_run(event, true);
 425                 return;
 426         }
 427 }
 428
 429 static void worker_kill(struct udev *udev, int retain)
 430 {
 431         struct udev_list_node *loop;
 432         int max;
 433
 434         if (childs <= retain)
 435                 return;
 436
 437         max = childs - retain;
 438
 439         udev_list_node_foreach(loop, &worker_list) {
 440                 struct worker *worker = node_to_worker(loop);
 441
 442                 if (max-- <= 0)
 443                         break;
 444
 445                 if (worker->state == WORKER_KILLED)
 446                         continue;
 447
 448                 worker->state = WORKER_KILLED;
 449                 kill(worker->pid, SIGTERM);
 450         }
 451 }
 452
 453 /* lookup event for identical, parent, child device */
 454 static bool is_devpath_busy(struct event *event)
 455 {
 456         struct udev_list_node *loop;
 457         size_t common;
 458
 459         /* check if queue contains events we depend on */
 460         udev_list_node_foreach(loop, &event_list) {
 461                 struct event *loop_event = node_to_event(loop);
 462
 463                 /* we already found a later event, earlier can not block us, no need to check again */
 464                 if (loop_event->seqnum < event->delaying_seqnum)
 465                         continue;
 466
 467                 /* event we checked earlier still exists, no need to check again */
 468                 if (loop_event->seqnum == event->delaying_seqnum)
 469                         return true;
 470
 471                 /* found ourself, no later event can block us */
 472                 if (loop_event->seqnum >= event->seqnum)
 473                         break;
 474
 475                 /* check major/minor */
 476                 if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
 477                         return true;
 478
 479                 /* check our old name */
 480                 if (event->devpath_old != NULL && strcmp(loop_event->devpath, event->devpath_old) == 0) {
 481                         event->delaying_seqnum = loop_event->seqnum;
 482                         return true;
 483                 }
 484
 485                 /* compare devpath */
 486                 common = MIN(loop_event->devpath_len, event->devpath_len);
 487
 488                 /* one devpath is contained in the other? */
 489                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 490                         continue;
 491
 492                 /* identical device event found */
 493                 if (loop_event->devpath_len == event->devpath_len) {
 494                         event->delaying_seqnum = loop_event->seqnum;
 495                         return true;
 496                 }
 497
 498                 /* parent device event found */
 499                 if (event->devpath[common] == '/') {
 500                         event->delaying_seqnum = loop_event->seqnum;
 501                         return true;
 502                 }
 503
 504                 /* child device event found */
 505                 if (loop_event->devpath[common] == '/') {
 506                         event->delaying_seqnum = loop_event->seqnum;
 507                         return true;
 508                 }
 509
 510                 /* no matching device */
 511                 continue;
 512         }
 513
 514         return false;
 515 }
 516
 517 static void events_start(struct udev *udev)
 518 {
 519         struct udev_list_node *loop;
 520
 521         udev_list_node_foreach(loop, &event_list) {
 522                 struct event *event = node_to_event(loop);
 523
 524                 if (event->state != EVENT_QUEUED)
 525                         continue;
 526
 527                 /* do not start event if parent or child event is still running */
 528                 if (is_devpath_busy(event)) {
 529                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 530                         continue;
 531                 }
 532
 533                 event_run(event, false);
 534         }
 535 }
 536
 537 static void worker_returned(void)
 538 {
 539         for (;;) {
 540                 struct worker_message msg;
 541                 ssize_t size;
 542                 struct udev_list_node *loop;
 543
 544                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 545                 if (size != sizeof(struct worker_message))
 546                         break;
 547
 548                 /* lookup worker who sent the signal */
 549                 udev_list_node_foreach(loop, &worker_list) {
 550                         struct worker *worker = node_to_worker(loop);
 551
 552                         if (worker->pid != msg.pid)
 553                                 continue;
 554
 555                         /* worker returned */
 556                         worker->event->exitcode = msg.exitcode;
 557                         event_queue_delete(worker->event);
 558                         worker->event = NULL;
 559                         if (worker->state != WORKER_KILLED)
 560                                 worker->state = WORKER_IDLE;
 561                         worker_unref(worker);
 562                         break;
 563                 }
 564         }
 565 }
 566
 567 /* receive the udevd message from userspace */
 568 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 569 {
 570         struct udev *udev = udev_ctrl_get_udev(uctrl);
 571         struct udev_ctrl_msg *ctrl_msg;
 572         const char *str;
 573         int i;
 574
 575         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 576         if (ctrl_msg == NULL)
 577                 return;
 578
 579         i = udev_ctrl_get_set_log_level(ctrl_msg);
 580         if (i >= 0) {
 581                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 582                 udev_set_log_priority(udev, i);
 583                 worker_kill(udev, 0);
 584         }
 585
 586         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 587                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 588                 stop_exec_queue = true;
 589         }
 590
 591         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 592                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 593                 stop_exec_queue = false;
 594         }
 595
 596         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 597                 info(udev, "udevd message (RELOAD_RULES) received\n");
 598                 reload_config = true;
 599         }
 600
 601         str = udev_ctrl_get_set_env(ctrl_msg);
 602         if (str != NULL) {
 603                 char *key;
 604
 605                 key = strdup(str);
 606                 if (key != NULL) {
 607                         char *val;
 608
 609                         val = strchr(key, '=');
 610                         if (val != NULL) {
 611                                 val[0] = '\0';
 612                                 val = &val[1];
 613                                 if (val[0] == '\0') {
 614                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 615                                         udev_add_property(udev, key, NULL);
 616                                 } else {
 617                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 618                                         udev_add_property(udev, key, val);
 619                                 }
 620                         } else {
 621                                 err(udev, "wrong key format '%s'\n", key);
 622                         }
 623                         free(key);
 624                 }
 625                 worker_kill(udev, 0);
 626         }
 627
 628         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 629         if (i >= 0) {
 630                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 631                 max_childs = i;
 632         }
 633
 634         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 635         if (settle_pid > 0) {
 636                 info(udev, "udevd message (SETTLE) received\n");
 637                 kill(settle_pid, SIGUSR1);
 638                 settle_pid = 0;
 639         }
 640         udev_ctrl_msg_unref(ctrl_msg);
 641 }
 642
 643 /* read inotify messages */
 644 static int handle_inotify(struct udev *udev)
 645 {
 646         int nbytes, pos;
 647         char *buf;
 648         struct inotify_event *ev;
 649
 650         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 651                 return 0;
 652
 653         buf = malloc(nbytes);
 654         if (buf == NULL) {
 655                 err(udev, "error getting buffer for inotify\n");
 656                 return -1;
 657         }
 658
 659         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 660
 661         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 662                 struct udev_device *dev;
 663
 664                 ev = (struct inotify_event *)(buf + pos);
 665                 if (ev->len) {
 666                         const char *s;
 667
 668                         info(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 669                         s = strstr(ev->name, ".rules");
 670                         if (s == NULL)
 671                                 continue;
 672                         if (strlen(s) != strlen(".rules"))
 673                                 continue;
 674                         reload_config = true;
 675                         continue;
 676                 }
 677
 678                 dev = udev_watch_lookup(udev, ev->wd);
 679                 if (dev != NULL) {
 680                         info(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 681                         if (ev->mask & IN_CLOSE_WRITE) {
 682                                 char filename[UTIL_PATH_SIZE];
 683                                 int fd;
 684
 685                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 686                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 687                                 fd = open(filename, O_WRONLY);
 688                                 if (fd < 0 || write(fd, "change", 6) < 0)
 689                                         info(udev, "error writing uevent: %m\n");
 690                                 close(fd);
 691                         }
 692                         if (ev->mask & IN_IGNORED)
 693                                 udev_watch_end(udev, dev);
 694
 695                         udev_device_unref(dev);
 696                 }
 697
 698         }
 699
 700         free(buf);
 701         return 0;
 702 }
 703
 704 static void handle_signal(struct udev *udev, int signo)
 705 {
 706         switch (signo) {
 707         case SIGINT:
 708         case SIGTERM:
 709                 udev_exit = true;
 710                 break;
 711         case SIGCHLD:
 712                 for (;;) {
 713                         pid_t pid;
 714                         int status;
 715                         struct udev_list_node *loop, *tmp;
 716
 717                         pid = waitpid(-1, &status, WNOHANG);
 718                         if (pid <= 0)
 719                                 break;
 720
 721                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 722                                 struct worker *worker = node_to_worker(loop);
 723
 724                                 if (worker->pid != pid)
 725                                         continue;
 726
 727                                 info(udev, "worker [%u] exit\n", pid);
 728                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 729                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 730                                         if (worker->event != NULL) {
 731                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 732                                                 worker->event->exitcode = -32;
 733                                                 event_queue_delete(worker->event);
 734                                                 /* drop reference from running event */
 735                                                 worker_unref(worker);
 736                                         }
 737                                 }
 738                                 worker_unref(worker);
 739                                 break;
 740                         }
 741                 }
 742                 break;
 743         case SIGHUP:
 744                 reload_config = true;
 745                 break;
 746         }
 747 }
 748
 749 static void static_dev_create_from_modules(struct udev *udev)
 750 {
 751         struct utsname kernel;
 752         char modules[UTIL_PATH_SIZE];
 753         char buf[4096];
 754         FILE *f;
 755
 756         uname(&kernel);
 757         util_strscpyl(modules, sizeof(modules), "/lib/modules/", kernel.release, "/modules.devname", NULL);
 758         f = fopen(modules, "r");
 759         if (f == NULL)
 760                 return;
 761
 762         while (fgets(buf, sizeof(buf), f) != NULL) {
 763                 char *s;
 764                 const char *modname;
 765                 const char *devname;
 766                 const char *devno;
 767                 int maj, min;
 768                 char type;
 769                 mode_t mode;
 770                 char filename[UTIL_PATH_SIZE];
 771
 772                 if (buf[0] == '#')
 773                         continue;
 774
 775                 modname = buf;
 776                 s = strchr(modname, ' ');
 777                 if (s == NULL)
 778                         continue;
 779                 s[0] = '\0';
 780
 781                 devname = &s[1];
 782                 s = strchr(devname, ' ');
 783                 if (s == NULL)
 784                         continue;
 785                 s[0] = '\0';
 786
 787                 devno = &s[1];
 788                 s = strchr(devno, ' ');
 789                 if (s == NULL)
 790                         s = strchr(devno, '\n');
 791                 if (s != NULL)
 792                         s[0] = '\0';
 793                 if (sscanf(devno, "%c%u:%u", &type, &maj, &min) != 3)
 794                         continue;
 795
 796                 if (type == 'c')
 797                         mode = 0600 | S_IFCHR;
 798                 else if (type == 'b')
 799                         mode = 0600 | S_IFBLK;
 800                 else
 801                         continue;
 802
 803                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/", devname, NULL);
 804                 util_create_path(udev, filename);
 805                 udev_selinux_setfscreatecon(udev, filename, mode);
 806                 info(udev, "mknod '%s' %c%u:%u\n", filename, type, maj, min);
 807                 if (mknod(filename, mode, makedev(maj, min)) < 0 && errno == EEXIST)
 808                         utimensat(AT_FDCWD, filename, NULL, 0);
 809                 udev_selinux_resetfscreatecon(udev);
 810         }
 811
 812         fclose(f);
 813 }
 814
 815 static int copy_dir(struct udev *udev, DIR *dir_from, DIR *dir_to, int maxdepth)
 816 {
 817         struct dirent *dent;
 818
 819         for (dent = readdir(dir_from); dent != NULL; dent = readdir(dir_from)) {
 820                 struct stat stats;
 821
 822                 if (dent->d_name[0] == '.')
 823                         continue;
 824                 if (fstatat(dirfd(dir_from), dent->d_name, &stats, AT_SYMLINK_NOFOLLOW) != 0)
 825                         continue;
 826
 827                 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
 828                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, stats.st_mode & 0777);
 829                         if (mknodat(dirfd(dir_to), dent->d_name, stats.st_mode, stats.st_rdev) == 0) {
 830                                 fchmodat(dirfd(dir_to), dent->d_name, stats.st_mode & 0777, 0);
 831                                 fchownat(dirfd(dir_to), dent->d_name, stats.st_uid, stats.st_gid, 0);
 832                         } else {
 833                                 utimensat(dirfd(dir_to), dent->d_name, NULL, 0);
 834                         }
 835                         udev_selinux_resetfscreatecon(udev);
 836                 } else if (S_ISLNK(stats.st_mode)) {
 837                         char target[UTIL_PATH_SIZE];
 838                         ssize_t len;
 839
 840                         len = readlinkat(dirfd(dir_from), dent->d_name, target, sizeof(target));
 841                         if (len <= 0 || len == (ssize_t)sizeof(target))
 842                                 continue;
 843                         target[len] = '\0';
 844                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFLNK);
 845                         if (symlinkat(target, dirfd(dir_to), dent->d_name) < 0 && errno == EEXIST)
 846                                 utimensat(dirfd(dir_to), dent->d_name, NULL, AT_SYMLINK_NOFOLLOW);
 847                         udev_selinux_resetfscreatecon(udev);
 848                 } else if (S_ISDIR(stats.st_mode)) {
 849                         DIR *dir2_from, *dir2_to;
 850
 851                         if (maxdepth == 0)
 852                                 continue;
 853
 854                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFDIR|0755);
 855                         mkdirat(dirfd(dir_to), dent->d_name, 0755);
 856                         udev_selinux_resetfscreatecon(udev);
 857
 858                         dir2_to = fdopendir(openat(dirfd(dir_to), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 859                         if (dir2_to == NULL)
 860                                 continue;
 861
 862                         dir2_from = fdopendir(openat(dirfd(dir_from), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 863                         if (dir2_from == NULL) {
 864                                 closedir(dir2_to);
 865                                 continue;
 866                         }
 867
 868                         copy_dir(udev, dir2_from, dir2_to, maxdepth-1);
 869
 870                         closedir(dir2_to);
 871                         closedir(dir2_from);
 872                 }
 873         }
 874
 875         return 0;
 876 }
 877
 878 static void static_dev_create_links(struct udev *udev, DIR *dir)
 879 {
 880         struct stdlinks {
 881                 const char *link;
 882                 const char *target;
 883         };
 884         static const struct stdlinks stdlinks[] = {
 885                 { "core", "/proc/kcore" },
 886                 { "fd", "/proc/self/fd" },
 887                 { "stdin", "/proc/self/fd/0" },
 888                 { "stdout", "/proc/self/fd/1" },
 889                 { "stderr", "/proc/self/fd/2" },
 890         };
 891         unsigned int i;
 892
 893         for (i = 0; i < ARRAY_SIZE(stdlinks); i++) {
 894                 udev_selinux_setfscreateconat(udev, dirfd(dir), stdlinks[i].link, S_IFLNK);
 895                 if (symlinkat(stdlinks[i].target, dirfd(dir), stdlinks[i].link) < 0 && errno == EEXIST)
 896                         utimensat(dirfd(dir), stdlinks[i].link, NULL, AT_SYMLINK_NOFOLLOW);
 897                 udev_selinux_resetfscreatecon(udev);
 898         }
 899 }
 900
 901 static void static_dev_create_from_devices(struct udev *udev, DIR *dir)
 902 {
 903         DIR *dir_from;
 904
 905         dir_from = opendir(LIBEXECDIR "/devices");
 906         if (dir_from == NULL)
 907                 return;
 908         copy_dir(udev, dir_from, dir, 8);
 909         closedir(dir_from);
 910 }
 911
 912 static void static_dev_create(struct udev *udev)
 913 {
 914         DIR *dir;
 915
 916         dir = opendir(udev_get_dev_path(udev));
 917         if (dir == NULL)
 918                 return;
 919
 920         static_dev_create_links(udev, dir);
 921         static_dev_create_from_devices(udev, dir);
 922
 923         closedir(dir);
 924 }
 925
 926 static int mem_size_mb(void)
 927 {
 928         FILE *f;
 929         char buf[4096];
 930         long int memsize = -1;
 931
 932         f = fopen("/proc/meminfo", "r");
 933         if (f == NULL)
 934                 return -1;
 935
 936         while (fgets(buf, sizeof(buf), f) != NULL) {
 937                 long int value;
 938
 939                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 940                         memsize = value / 1024;
 941                         break;
 942                 }
 943         }
 944
 945         fclose(f);
 946         return memsize;
 947 }
 948
 949 int main(int argc, char *argv[])
 950 {
 951         struct udev *udev;
 952         int fd;
 953         FILE *f;
 954         sigset_t mask;
 955         const char *value;
 956         int daemonize = false;
 957         int resolve_names = 1;
 958         static const struct option options[] = {
 959                 { "daemon", no_argument, NULL, 'd' },
 960                 { "debug-trace", no_argument, NULL, 't' },
 961                 { "debug", no_argument, NULL, 'D' },
 962                 { "help", no_argument, NULL, 'h' },
 963                 { "version", no_argument, NULL, 'V' },
 964                 { "resolve-names", required_argument, NULL, 'N' },
 965                 {}
 966         };
 967         int rc = 1;
 968
 969         udev = udev_new();
 970         if (udev == NULL)
 971                 goto exit;
 972
 973         udev_log_init("udevd");
 974         udev_set_log_fn(udev, log_fn);
 975         info(udev, "version %s\n", VERSION);
 976         udev_selinux_init(udev);
 977
 978         for (;;) {
 979                 int option;
 980
 981                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 982                 if (option == -1)
 983                         break;
 984
 985                 switch (option) {
 986                 case 'd':
 987                         daemonize = true;
 988                         break;
 989                 case 't':
 990                         debug_trace = true;
 991                         break;
 992                 case 'D':
 993                         debug = true;
 994                         if (udev_get_log_priority(udev) < LOG_INFO)
 995                                 udev_set_log_priority(udev, LOG_INFO);
 996                         break;
 997                 case 'N':
 998                         if (strcmp (optarg, "early") == 0) {
 999                                 resolve_names = 1;
1000                         } else if (strcmp (optarg, "late") == 0) {
1001                                 resolve_names = 0;
1002                         } else if (strcmp (optarg, "never") == 0) {
1003                                 resolve_names = -1;
1004                         } else {
1005                                 fprintf(stderr, "resolve-names must be early, late or never\n");
1006                                 err(udev, "resolve-names must be early, late or never\n");
1007                                 goto exit;
1008                         }
1009                         break;
1010                 case 'h':
1011                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
1012                                "[--resolve-names=early|late|never] [--version]\n");
1013                         goto exit;
1014                 case 'V':
1015                         printf("%s\n", VERSION);
1016                         goto exit;
1017                 default:
1018                         goto exit;
1019                 }
1020         }
1021
1022         if (getuid() != 0) {
1023                 fprintf(stderr, "root privileges required\n");
1024                 err(udev, "root privileges required\n");
1025                 goto exit;
1026         }
1027
1028         /* make sure std{in,out,err} fd's are in a sane state */
1029         fd = open("/dev/null", O_RDWR);
1030         if (fd < 0) {
1031                 fprintf(stderr, "cannot open /dev/null\n");
1032                 err(udev, "cannot open /dev/null\n");
1033         }
1034         if (write(STDOUT_FILENO, 0, 0) < 0)
1035                 dup2(fd, STDOUT_FILENO);
1036         if (write(STDERR_FILENO, 0, 0) < 0)
1037                 dup2(fd, STDERR_FILENO);
1038
1039         /* init control socket, bind() ensures, that only one udevd instance is running */
1040         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
1041         if (udev_ctrl == NULL) {
1042                 fprintf(stderr, "error initializing control socket");
1043                 err(udev, "error initializing udevd socket");
1044                 rc = 1;
1045                 goto exit;
1046         }
1047         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
1048                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
1049                 err(udev, "error binding control socket, seems udevd is already running\n");
1050                 rc = 1;
1051                 goto exit;
1052         }
1053         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
1054
1055         monitor = udev_monitor_new_from_netlink(udev, "kernel");
1056         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
1057                 fprintf(stderr, "error initializing netlink socket\n");
1058                 err(udev, "error initializing netlink socket\n");
1059                 rc = 3;
1060                 goto exit;
1061         }
1062         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
1063         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
1064
1065         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
1066         if (pfd[FD_INOTIFY].fd < 0) {
1067                 fprintf(stderr, "error initializing inotify\n");
1068                 err(udev, "error initializing inotify\n");
1069                 rc = 4;
1070                 goto exit;
1071         }
1072
1073         if (udev_get_rules_path(udev) != NULL) {
1074                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
1075                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1076         } else {
1077                 char filename[UTIL_PATH_SIZE];
1078                 struct stat statbuf;
1079
1080                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
1081                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1082                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
1083                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1084
1085                 /* watch dynamic rules directory */
1086                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
1087                 if (stat(filename, &statbuf) != 0) {
1088                         util_create_path(udev, filename);
1089                         udev_selinux_setfscreatecon(udev, filename, S_IFDIR|0755);
1090                         mkdir(filename, 0755);
1091                         udev_selinux_resetfscreatecon(udev);
1092                 }
1093                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
1094                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1095         }
1096         udev_watch_restore(udev);
1097
1098         /* block and listen to all signals on signalfd */
1099         sigfillset(&mask);
1100         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
1101         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
1102         if (pfd[FD_SIGNAL].fd < 0) {
1103                 fprintf(stderr, "error getting signalfd\n");
1104                 err(udev, "error getting signalfd\n");
1105                 rc = 5;
1106                 goto exit;
1107         }
1108
1109         /* unnamed socket from workers to the main daemon */
1110         if (socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, worker_watch) < 0) {
1111                 fprintf(stderr, "error getting socketpair\n");
1112                 err(udev, "error getting socketpair\n");
1113                 rc = 6;
1114                 goto exit;
1115         }
1116         pfd[FD_WORKER].fd = worker_watch[READ_END];
1117
1118         rules = udev_rules_new(udev, resolve_names);
1119         if (rules == NULL) {
1120                 err(udev, "error reading rules\n");
1121                 goto exit;
1122         }
1123
1124         udev_queue_export = udev_queue_export_new(udev);
1125         if (udev_queue_export == NULL) {
1126                 err(udev, "error creating queue file\n");
1127                 goto exit;
1128         }
1129
1130         if (daemonize) {
1131                 pid_t pid;
1132
1133                 pid = fork();
1134                 switch (pid) {
1135                 case 0:
1136                         break;
1137                 case -1:
1138                         err(udev, "fork of daemon failed: %m\n");
1139                         rc = 4;
1140                         goto exit;
1141                 default:
1142                         rc = 0;
1143                         goto exit;
1144                 }
1145         }
1146
1147         f = fopen("/dev/kmsg", "w");
1148         if (f != NULL) {
1149                 fprintf(f, "<6>udev: starting version " VERSION "\n");
1150                 fclose(f);
1151         }
1152
1153         /* redirect std{out,err} */
1154         if (!debug && !debug_trace) {
1155                 dup2(fd, STDIN_FILENO);
1156                 dup2(fd, STDOUT_FILENO);
1157                 dup2(fd, STDERR_FILENO);
1158         }
1159         if (fd > STDERR_FILENO)
1160                 close(fd);
1161
1162         /* set scheduling priority for the daemon */
1163         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1164
1165         chdir("/");
1166         umask(022);
1167         setsid();
1168
1169         /* OOM_DISABLE == -17 */
1170         fd = open("/proc/self/oom_adj", O_RDWR);
1171         if (fd < 0) {
1172                 err(udev, "error disabling OOM: %m\n");
1173         } else {
1174                 write(fd, "-17", 3);
1175                 close(fd);
1176         }
1177
1178         /* in trace mode run one event after the other */
1179         if (debug_trace) {
1180                 max_childs = 1;
1181         } else {
1182                 int memsize = mem_size_mb();
1183
1184                 if (memsize > 0)
1185                         max_childs = 128 + (memsize / 8);
1186                 else
1187                         max_childs = 128;
1188         }
1189
1190         /* possibly overwrite maximum limit of executed events */
1191         value = getenv("UDEVD_MAX_CHILDS");
1192         if (value)
1193                 max_childs = strtoul(value, NULL, 10);
1194         info(udev, "initialize max_childs to %u\n", max_childs);
1195
1196         static_dev_create(udev);
1197         static_dev_create_from_modules(udev);
1198         udev_rules_apply_static_dev_perms(rules);
1199
1200         udev_list_init(&event_list);
1201         udev_list_init(&worker_list);
1202
1203         while (!udev_exit) {
1204                 int fdcount;
1205                 int timeout;
1206
1207                 /* set timeout to kill idle workers */
1208                 if (udev_list_is_empty(&event_list) && childs > 2)
1209                         timeout = 3 * 1000;
1210                 else
1211                         timeout = -1;
1212                 /* wait for events */
1213                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1214                 if (fdcount < 0)
1215                         continue;
1216
1217                 /* timeout - kill idle workers */
1218                 if (fdcount == 0)
1219                         worker_kill(udev, 2);
1220
1221                 /* event has finished */
1222                 if (pfd[FD_WORKER].revents & POLLIN)
1223                         worker_returned();
1224
1225                 /* get kernel uevent */
1226                 if (pfd[FD_NETLINK].revents & POLLIN) {
1227                         struct udev_device *dev;
1228
1229                         dev = udev_monitor_receive_device(monitor);
1230                         if (dev != NULL)
1231                                 event_queue_insert(dev);
1232                         else
1233                                 udev_device_unref(dev);
1234                 }
1235
1236                 /* start new events */
1237                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1238                         events_start(udev);
1239
1240                 /* get signal */
1241                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1242                         struct signalfd_siginfo fdsi;
1243                         ssize_t size;
1244
1245                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1246                         if (size == sizeof(struct signalfd_siginfo))
1247                                 handle_signal(udev, fdsi.ssi_signo);
1248                 }
1249
1250                 /* device node and rules directory inotify watch */
1251                 if (pfd[FD_INOTIFY].revents & POLLIN)
1252                         handle_inotify(udev);
1253
1254                 /*
1255                  * get control message
1256                  *
1257                  * This needs to be after the inotify handling, to make sure,
1258                  * that the settle signal is send back after the possibly generated
1259                  * "change" events by the inotify device node watch.
1260                  */
1261                 if (pfd[FD_CONTROL].revents & POLLIN)
1262                         handle_ctrl_msg(udev_ctrl);
1263
1264                 /* rules changed, set by inotify or a HUP signal */
1265                 if (reload_config) {
1266                         struct udev_rules *rules_new;
1267
1268                         worker_kill(udev, 0);
1269                         rules_new = udev_rules_new(udev, resolve_names);
1270                         if (rules_new != NULL) {
1271                                 udev_rules_unref(rules);
1272                                 rules = rules_new;
1273                         }
1274                         reload_config = 0;
1275                 }
1276         }
1277
1278         udev_queue_export_cleanup(udev_queue_export);
1279         rc = 0;
1280 exit:
1281         udev_queue_export_unref(udev_queue_export);
1282         udev_rules_unref(rules);
1283         udev_ctrl_unref(udev_ctrl);
1284         if (pfd[FD_SIGNAL].fd >= 0)
1285                 close(pfd[FD_SIGNAL].fd);
1286         if (worker_watch[READ_END] >= 0)
1287                 close(worker_watch[READ_END]);
1288         if (worker_watch[WRITE_END] >= 0)
1289                 close(worker_watch[WRITE_END]);
1290         udev_monitor_unref(monitor);
1291         udev_selinux_exit(udev);
1292         udev_unref(udev);
1293         udev_log_close();
1294         return rc;
1295 }