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 int exec_delay;
  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         children--;
 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                         if (exec_delay > 0)
 290                                 udev_event->exec_delay = exec_delay;
 291
 292                         /* apply rules, create node, symlinks */
 293                         err = udev_event_execute_rules(udev_event, rules);
 294
 295                         /* rules may change/disable the timeout */
 296                         if (udev_device_get_event_timeout(dev) >= 0)
 297                                 alarm(udev_device_get_event_timeout(dev));
 298
 299                         if (err == 0)
 300                                 failed = udev_event_execute_run(udev_event, &orig_sigmask);
 301
 302                         alarm(0);
 303
 304                         /* apply/restore inotify watch */
 305                         if (err == 0 && udev_event->inotify_watch) {
 306                                 udev_watch_begin(udev_event->udev, dev);
 307                                 udev_device_update_db(dev);
 308                         }
 309
 310                         /* send processed event back to libudev listeners */
 311                         udev_monitor_send_device(worker_monitor, NULL, dev);
 312
 313                         /* send udevd the result of the event execution */
 314                         if (err != 0)
 315                                 msg.exitcode = err;
 316                         else if (failed != 0)
 317                                 msg.exitcode = failed;
 318                         msg.pid = getpid();
 319                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 320
 321                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 322                         udev_event_unref(udev_event);
 323                         udev_device_unref(dev);
 324                         dev = NULL;
 325
 326                         /* wait for more device messages or signal from udevd */
 327                         while (!worker_exit) {
 328                                 int fdcount;
 329
 330                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 331                                 if (fdcount < 0)
 332                                         continue;
 333
 334                                 if (pmon.revents & POLLIN) {
 335                                         dev = udev_monitor_receive_device(worker_monitor);
 336                                         if (dev != NULL)
 337                                                 break;
 338                                 }
 339                         }
 340                 } while (dev != NULL);
 341
 342                 udev_monitor_unref(worker_monitor);
 343                 udev_log_close();
 344                 exit(0);
 345         }
 346         case -1:
 347                 udev_monitor_unref(worker_monitor);
 348                 event->state = EVENT_QUEUED;
 349                 free(worker);
 350                 err(event->udev, "fork of child failed: %m\n");
 351                 break;
 352         default:
 353                 /* close monitor, but keep address around */
 354                 udev_monitor_disconnect(worker_monitor);
 355                 worker->monitor = worker_monitor;
 356                 worker->pid = pid;
 357                 worker->state = WORKER_RUNNING;
 358                 worker->event = event;
 359                 event->state = EVENT_RUNNING;
 360                 udev_list_node_append(&worker->node, &worker_list);
 361                 children++;
 362                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 363                 break;
 364         }
 365 }
 366
 367 static void event_run(struct event *event, bool force)
 368 {
 369         struct udev_list_node *loop;
 370
 371         udev_list_node_foreach(loop, &worker_list) {
 372                 struct worker *worker = node_to_worker(loop);
 373                 ssize_t count;
 374
 375                 if (worker->state != WORKER_IDLE)
 376                         continue;
 377
 378                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 379                 if (count < 0) {
 380                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 381                         kill(worker->pid, SIGKILL);
 382                         worker->state = WORKER_KILLED;
 383                         continue;
 384                 }
 385                 worker_ref(worker);
 386                 worker->event = event;
 387                 worker->state = WORKER_RUNNING;
 388                 event->state = EVENT_RUNNING;
 389                 return;
 390         }
 391
 392         if (!force && children >= children_max) {
 393                 if (children_max > 1)
 394                         info(event->udev, "maximum number (%i) of children reached\n", children);
 395                 return;
 396         }
 397
 398         /* start new worker and pass initial device */
 399         worker_new(event);
 400 }
 401
 402 static void event_queue_insert(struct udev_device *dev)
 403 {
 404         struct event *event;
 405
 406         event = calloc(1, sizeof(struct event));
 407         if (event == NULL)
 408                 return;
 409
 410         event->udev = udev_device_get_udev(dev);
 411         event->dev = dev;
 412         event->seqnum = udev_device_get_seqnum(dev);
 413         event->devpath = udev_device_get_devpath(dev);
 414         event->devpath_len = strlen(event->devpath);
 415         event->devpath_old = udev_device_get_devpath_old(dev);
 416         event->devnum = udev_device_get_devnum(dev);
 417         event->is_block = (strcmp("block", udev_device_get_subsystem(dev)) == 0);
 418
 419         udev_queue_export_device_queued(udev_queue_export, dev);
 420         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 421              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 422
 423         event->state = EVENT_QUEUED;
 424         udev_list_node_append(&event->node, &event_list);
 425
 426         /* run all events with a timeout set immediately */
 427         if (udev_device_get_timeout(dev) > 0) {
 428                 event_run(event, true);
 429                 return;
 430         }
 431 }
 432
 433 static void worker_kill(struct udev *udev, int retain)
 434 {
 435         struct udev_list_node *loop;
 436         int max;
 437
 438         if (children <= retain)
 439                 return;
 440
 441         max = children - retain;
 442
 443         udev_list_node_foreach(loop, &worker_list) {
 444                 struct worker *worker = node_to_worker(loop);
 445
 446                 if (max-- <= 0)
 447                         break;
 448
 449                 if (worker->state == WORKER_KILLED)
 450                         continue;
 451
 452                 worker->state = WORKER_KILLED;
 453                 kill(worker->pid, SIGTERM);
 454         }
 455 }
 456
 457 /* lookup event for identical, parent, child device */
 458 static bool is_devpath_busy(struct event *event)
 459 {
 460         struct udev_list_node *loop;
 461         size_t common;
 462
 463         /* check if queue contains events we depend on */
 464         udev_list_node_foreach(loop, &event_list) {
 465                 struct event *loop_event = node_to_event(loop);
 466
 467                 /* we already found a later event, earlier can not block us, no need to check again */
 468                 if (loop_event->seqnum < event->delaying_seqnum)
 469                         continue;
 470
 471                 /* event we checked earlier still exists, no need to check again */
 472                 if (loop_event->seqnum == event->delaying_seqnum)
 473                         return true;
 474
 475                 /* found ourself, no later event can block us */
 476                 if (loop_event->seqnum >= event->seqnum)
 477                         break;
 478
 479                 /* check major/minor */
 480                 if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
 481                         return true;
 482
 483                 /* check our old name */
 484                 if (event->devpath_old != NULL && strcmp(loop_event->devpath, event->devpath_old) == 0) {
 485                         event->delaying_seqnum = loop_event->seqnum;
 486                         return true;
 487                 }
 488
 489                 /* compare devpath */
 490                 common = MIN(loop_event->devpath_len, event->devpath_len);
 491
 492                 /* one devpath is contained in the other? */
 493                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 494                         continue;
 495
 496                 /* identical device event found */
 497                 if (loop_event->devpath_len == event->devpath_len) {
 498                         event->delaying_seqnum = loop_event->seqnum;
 499                         return true;
 500                 }
 501
 502                 /* parent device event found */
 503                 if (event->devpath[common] == '/') {
 504                         event->delaying_seqnum = loop_event->seqnum;
 505                         return true;
 506                 }
 507
 508                 /* child device event found */
 509                 if (loop_event->devpath[common] == '/') {
 510                         event->delaying_seqnum = loop_event->seqnum;
 511                         return true;
 512                 }
 513
 514                 /* no matching device */
 515                 continue;
 516         }
 517
 518         return false;
 519 }
 520
 521 static void events_start(struct udev *udev)
 522 {
 523         struct udev_list_node *loop;
 524
 525         udev_list_node_foreach(loop, &event_list) {
 526                 struct event *event = node_to_event(loop);
 527
 528                 if (event->state != EVENT_QUEUED)
 529                         continue;
 530
 531                 /* do not start event if parent or child event is still running */
 532                 if (is_devpath_busy(event)) {
 533                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 534                         continue;
 535                 }
 536
 537                 event_run(event, false);
 538         }
 539 }
 540
 541 static void worker_returned(void)
 542 {
 543         for (;;) {
 544                 struct worker_message msg;
 545                 ssize_t size;
 546                 struct udev_list_node *loop;
 547
 548                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 549                 if (size != sizeof(struct worker_message))
 550                         break;
 551
 552                 /* lookup worker who sent the signal */
 553                 udev_list_node_foreach(loop, &worker_list) {
 554                         struct worker *worker = node_to_worker(loop);
 555
 556                         if (worker->pid != msg.pid)
 557                                 continue;
 558
 559                         /* worker returned */
 560                         worker->event->exitcode = msg.exitcode;
 561                         event_queue_delete(worker->event);
 562                         worker->event = NULL;
 563                         if (worker->state != WORKER_KILLED)
 564                                 worker->state = WORKER_IDLE;
 565                         worker_unref(worker);
 566                         break;
 567                 }
 568         }
 569 }
 570
 571 /* receive the udevd message from userspace */
 572 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 573 {
 574         struct udev *udev = udev_ctrl_get_udev(uctrl);
 575         struct udev_ctrl_msg *ctrl_msg;
 576         const char *str;
 577         int i;
 578
 579         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 580         if (ctrl_msg == NULL)
 581                 return;
 582
 583         i = udev_ctrl_get_set_log_level(ctrl_msg);
 584         if (i >= 0) {
 585                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 586                 udev_set_log_priority(udev, i);
 587                 worker_kill(udev, 0);
 588         }
 589
 590         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 591                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 592                 stop_exec_queue = true;
 593         }
 594
 595         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 596                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 597                 stop_exec_queue = false;
 598         }
 599
 600         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 601                 info(udev, "udevd message (RELOAD_RULES) received\n");
 602                 reload_config = true;
 603         }
 604
 605         str = udev_ctrl_get_set_env(ctrl_msg);
 606         if (str != NULL) {
 607                 char *key;
 608
 609                 key = strdup(str);
 610                 if (key != NULL) {
 611                         char *val;
 612
 613                         val = strchr(key, '=');
 614                         if (val != NULL) {
 615                                 val[0] = '\0';
 616                                 val = &val[1];
 617                                 if (val[0] == '\0') {
 618                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 619                                         udev_add_property(udev, key, NULL);
 620                                 } else {
 621                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 622                                         udev_add_property(udev, key, val);
 623                                 }
 624                         } else {
 625                                 err(udev, "wrong key format '%s'\n", key);
 626                         }
 627                         free(key);
 628                 }
 629                 worker_kill(udev, 0);
 630         }
 631
 632         i = udev_ctrl_get_set_children_max(ctrl_msg);
 633         if (i >= 0) {
 634                 info(udev, "udevd message (SET_MAX_CHILDREN) received, children_max=%i\n", i);
 635                 children_max = i;
 636         }
 637
 638         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 639         if (settle_pid > 0) {
 640                 info(udev, "udevd message (SETTLE) received\n");
 641                 kill(settle_pid, SIGUSR1);
 642                 settle_pid = 0;
 643         }
 644         udev_ctrl_msg_unref(ctrl_msg);
 645 }
 646
 647 /* read inotify messages */
 648 static int handle_inotify(struct udev *udev)
 649 {
 650         int nbytes, pos;
 651         char *buf;
 652         struct inotify_event *ev;
 653
 654         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 655                 return 0;
 656
 657         buf = malloc(nbytes);
 658         if (buf == NULL) {
 659                 err(udev, "error getting buffer for inotify\n");
 660                 return -1;
 661         }
 662
 663         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 664
 665         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 666                 struct udev_device *dev;
 667
 668                 ev = (struct inotify_event *)(buf + pos);
 669                 if (ev->len) {
 670                         const char *s;
 671
 672                         info(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 673                         s = strstr(ev->name, ".rules");
 674                         if (s == NULL)
 675                                 continue;
 676                         if (strlen(s) != strlen(".rules"))
 677                                 continue;
 678                         reload_config = true;
 679                         continue;
 680                 }
 681
 682                 dev = udev_watch_lookup(udev, ev->wd);
 683                 if (dev != NULL) {
 684                         info(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 685                         if (ev->mask & IN_CLOSE_WRITE) {
 686                                 char filename[UTIL_PATH_SIZE];
 687                                 int fd;
 688
 689                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 690                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 691                                 fd = open(filename, O_WRONLY);
 692                                 if (fd < 0 || write(fd, "change", 6) < 0)
 693                                         info(udev, "error writing uevent: %m\n");
 694                                 close(fd);
 695                         }
 696                         if (ev->mask & IN_IGNORED)
 697                                 udev_watch_end(udev, dev);
 698
 699                         udev_device_unref(dev);
 700                 }
 701
 702         }
 703
 704         free(buf);
 705         return 0;
 706 }
 707
 708 static void handle_signal(struct udev *udev, int signo)
 709 {
 710         switch (signo) {
 711         case SIGINT:
 712         case SIGTERM:
 713                 udev_exit = true;
 714                 break;
 715         case SIGCHLD:
 716                 for (;;) {
 717                         pid_t pid;
 718                         int status;
 719                         struct udev_list_node *loop, *tmp;
 720
 721                         pid = waitpid(-1, &status, WNOHANG);
 722                         if (pid <= 0)
 723                                 break;
 724
 725                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 726                                 struct worker *worker = node_to_worker(loop);
 727
 728                                 if (worker->pid != pid)
 729                                         continue;
 730
 731                                 info(udev, "worker [%u] exit\n", pid);
 732                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 733                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 734                                         if (worker->event != NULL) {
 735                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 736                                                 worker->event->exitcode = -32;
 737                                                 event_queue_delete(worker->event);
 738                                                 /* drop reference from running event */
 739                                                 worker_unref(worker);
 740                                         }
 741                                 }
 742                                 worker_unref(worker);
 743                                 break;
 744                         }
 745                 }
 746                 break;
 747         case SIGHUP:
 748                 reload_config = true;
 749                 break;
 750         }
 751 }
 752
 753 static void static_dev_create_from_modules(struct udev *udev)
 754 {
 755         struct utsname kernel;
 756         char modules[UTIL_PATH_SIZE];
 757         char buf[4096];
 758         FILE *f;
 759
 760         uname(&kernel);
 761         util_strscpyl(modules, sizeof(modules), "/lib/modules/", kernel.release, "/modules.devname", NULL);
 762         f = fopen(modules, "r");
 763         if (f == NULL)
 764                 return;
 765
 766         while (fgets(buf, sizeof(buf), f) != NULL) {
 767                 char *s;
 768                 const char *modname;
 769                 const char *devname;
 770                 const char *devno;
 771                 int maj, min;
 772                 char type;
 773                 mode_t mode;
 774                 char filename[UTIL_PATH_SIZE];
 775
 776                 if (buf[0] == '#')
 777                         continue;
 778
 779                 modname = buf;
 780                 s = strchr(modname, ' ');
 781                 if (s == NULL)
 782                         continue;
 783                 s[0] = '\0';
 784
 785                 devname = &s[1];
 786                 s = strchr(devname, ' ');
 787                 if (s == NULL)
 788                         continue;
 789                 s[0] = '\0';
 790
 791                 devno = &s[1];
 792                 s = strchr(devno, ' ');
 793                 if (s == NULL)
 794                         s = strchr(devno, '\n');
 795                 if (s != NULL)
 796                         s[0] = '\0';
 797                 if (sscanf(devno, "%c%u:%u", &type, &maj, &min) != 3)
 798                         continue;
 799
 800                 if (type == 'c')
 801                         mode = 0600 | S_IFCHR;
 802                 else if (type == 'b')
 803                         mode = 0600 | S_IFBLK;
 804                 else
 805                         continue;
 806
 807                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/", devname, NULL);
 808                 util_create_path(udev, filename);
 809                 udev_selinux_setfscreatecon(udev, filename, mode);
 810                 info(udev, "mknod '%s' %c%u:%u\n", filename, type, maj, min);
 811                 if (mknod(filename, mode, makedev(maj, min)) < 0 && errno == EEXIST)
 812                         utimensat(AT_FDCWD, filename, NULL, 0);
 813                 udev_selinux_resetfscreatecon(udev);
 814         }
 815
 816         fclose(f);
 817 }
 818
 819 static int copy_dir(struct udev *udev, DIR *dir_from, DIR *dir_to, int maxdepth)
 820 {
 821         struct dirent *dent;
 822
 823         for (dent = readdir(dir_from); dent != NULL; dent = readdir(dir_from)) {
 824                 struct stat stats;
 825
 826                 if (dent->d_name[0] == '.')
 827                         continue;
 828                 if (fstatat(dirfd(dir_from), dent->d_name, &stats, AT_SYMLINK_NOFOLLOW) != 0)
 829                         continue;
 830
 831                 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
 832                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, stats.st_mode & 0777);
 833                         if (mknodat(dirfd(dir_to), dent->d_name, stats.st_mode, stats.st_rdev) == 0) {
 834                                 fchmodat(dirfd(dir_to), dent->d_name, stats.st_mode & 0777, 0);
 835                                 fchownat(dirfd(dir_to), dent->d_name, stats.st_uid, stats.st_gid, 0);
 836                         } else {
 837                                 utimensat(dirfd(dir_to), dent->d_name, NULL, 0);
 838                         }
 839                         udev_selinux_resetfscreatecon(udev);
 840                 } else if (S_ISLNK(stats.st_mode)) {
 841                         char target[UTIL_PATH_SIZE];
 842                         ssize_t len;
 843
 844                         len = readlinkat(dirfd(dir_from), dent->d_name, target, sizeof(target));
 845                         if (len <= 0 || len == (ssize_t)sizeof(target))
 846                                 continue;
 847                         target[len] = '\0';
 848                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFLNK);
 849                         if (symlinkat(target, dirfd(dir_to), dent->d_name) < 0 && errno == EEXIST)
 850                                 utimensat(dirfd(dir_to), dent->d_name, NULL, AT_SYMLINK_NOFOLLOW);
 851                         udev_selinux_resetfscreatecon(udev);
 852                 } else if (S_ISDIR(stats.st_mode)) {
 853                         DIR *dir2_from, *dir2_to;
 854
 855                         if (maxdepth == 0)
 856                                 continue;
 857
 858                         udev_selinux_setfscreateconat(udev, dirfd(dir_to), dent->d_name, S_IFDIR|0755);
 859                         mkdirat(dirfd(dir_to), dent->d_name, 0755);
 860                         udev_selinux_resetfscreatecon(udev);
 861
 862                         dir2_to = fdopendir(openat(dirfd(dir_to), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 863                         if (dir2_to == NULL)
 864                                 continue;
 865
 866                         dir2_from = fdopendir(openat(dirfd(dir_from), dent->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC));
 867                         if (dir2_from == NULL) {
 868                                 closedir(dir2_to);
 869                                 continue;
 870                         }
 871
 872                         copy_dir(udev, dir2_from, dir2_to, maxdepth-1);
 873
 874                         closedir(dir2_to);
 875                         closedir(dir2_from);
 876                 }
 877         }
 878
 879         return 0;
 880 }
 881
 882 static void static_dev_create_links(struct udev *udev, DIR *dir)
 883 {
 884         struct stdlinks {
 885                 const char *link;
 886                 const char *target;
 887         };
 888         static const struct stdlinks stdlinks[] = {
 889                 { "core", "/proc/kcore" },
 890                 { "fd", "/proc/self/fd" },
 891                 { "stdin", "/proc/self/fd/0" },
 892                 { "stdout", "/proc/self/fd/1" },
 893                 { "stderr", "/proc/self/fd/2" },
 894         };
 895         unsigned int i;
 896
 897         for (i = 0; i < ARRAY_SIZE(stdlinks); i++) {
 898                 udev_selinux_setfscreateconat(udev, dirfd(dir), stdlinks[i].link, S_IFLNK);
 899                 if (symlinkat(stdlinks[i].target, dirfd(dir), stdlinks[i].link) < 0 && errno == EEXIST)
 900                         utimensat(dirfd(dir), stdlinks[i].link, NULL, AT_SYMLINK_NOFOLLOW);
 901                 udev_selinux_resetfscreatecon(udev);
 902         }
 903 }
 904
 905 static void static_dev_create_from_devices(struct udev *udev, DIR *dir)
 906 {
 907         DIR *dir_from;
 908
 909         dir_from = opendir(LIBEXECDIR "/devices");
 910         if (dir_from == NULL)
 911                 return;
 912         copy_dir(udev, dir_from, dir, 8);
 913         closedir(dir_from);
 914 }
 915
 916 static void static_dev_create(struct udev *udev)
 917 {
 918         DIR *dir;
 919
 920         dir = opendir(udev_get_dev_path(udev));
 921         if (dir == NULL)
 922                 return;
 923
 924         static_dev_create_links(udev, dir);
 925         static_dev_create_from_devices(udev, dir);
 926
 927         closedir(dir);
 928 }
 929
 930 static int mem_size_mb(void)
 931 {
 932         FILE *f;
 933         char buf[4096];
 934         long int memsize = -1;
 935
 936         f = fopen("/proc/meminfo", "r");
 937         if (f == NULL)
 938                 return -1;
 939
 940         while (fgets(buf, sizeof(buf), f) != NULL) {
 941                 long int value;
 942
 943                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 944                         memsize = value / 1024;
 945                         break;
 946                 }
 947         }
 948
 949         fclose(f);
 950         return memsize;
 951 }
 952
 953 int main(int argc, char *argv[])
 954 {
 955         struct udev *udev;
 956         int fd;
 957         FILE *f;
 958         sigset_t mask;
 959         int daemonize = false;
 960         int resolve_names = 1;
 961         static const struct option options[] = {
 962                 { "daemon", no_argument, NULL, 'd' },
 963                 { "debug", no_argument, NULL, 'D' },
 964                 { "children-max", required_argument, NULL, 'c' },
 965                 { "exec-delay", required_argument, NULL, 'e' },
 966                 { "resolve-names", required_argument, NULL, 'N' },
 967                 { "help", no_argument, NULL, 'h' },
 968                 { "version", no_argument, NULL, 'V' },
 969                 {}
 970         };
 971         int rc = 1;
 972
 973         udev = udev_new();
 974         if (udev == NULL)
 975                 goto exit;
 976
 977         udev_log_init("udevd");
 978         udev_set_log_fn(udev, log_fn);
 979         info(udev, "version %s\n", VERSION);
 980         udev_selinux_init(udev);
 981
 982         for (;;) {
 983                 int option;
 984
 985                 option = getopt_long(argc, argv, "cdeDthV", options, NULL);
 986                 if (option == -1)
 987                         break;
 988
 989                 switch (option) {
 990                 case 'd':
 991                         daemonize = true;
 992                         break;
 993                 case 'c':
 994                         children_max = strtoul(optarg, NULL, 0);
 995                         break;
 996                 case 'e':
 997                         exec_delay = strtoul(optarg, NULL, 0);
 998                         break;
 999                 case 'D':
1000                         debug = true;
1001                         if (udev_get_log_priority(udev) < LOG_INFO)
1002                                 udev_set_log_priority(udev, LOG_INFO);
1003                         break;
1004                 case 'N':
1005                         if (strcmp (optarg, "early") == 0) {
1006                                 resolve_names = 1;
1007                         } else if (strcmp (optarg, "late") == 0) {
1008                                 resolve_names = 0;
1009                         } else if (strcmp (optarg, "never") == 0) {
1010                                 resolve_names = -1;
1011                         } else {
1012                                 fprintf(stderr, "resolve-names must be early, late or never\n");
1013                                 err(udev, "resolve-names must be early, late or never\n");
1014                                 goto exit;
1015                         }
1016                         break;
1017                 case 'h':
1018                         printf("Usage: udevd OPTIONS\n"
1019                                "  --daemon\n"
1020                                "  --debug\n"
1021                                "  --children-max=<maximum number of workers>\n"
1022                                "  --exec-delay=<seconds to wait before executing RUN=>\n"
1023                                "  --resolve-names=early|late|never\n"
1024                                "  --version\n"
1025                                "  --help\n"
1026                                "\n");
1027                         goto exit;
1028                 case 'V':
1029                         printf("%s\n", VERSION);
1030                         goto exit;
1031                 default:
1032                         goto exit;
1033                 }
1034         }
1035
1036         if (getuid() != 0) {
1037                 fprintf(stderr, "root privileges required\n");
1038                 err(udev, "root privileges required\n");
1039                 goto exit;
1040         }
1041
1042         /*
1043          * read the kernel commandline, in case we need to get into debug mode
1044          *   udev.log-priority=<level>              syslog priority
1045          *   udev.children-max=<number of workers>  events are fully serialized if set to 1
1046          *
1047          */
1048         f = fopen("/proc/cmdline", "r");
1049         if (f != NULL) {
1050                 char cmdline[4096];
1051
1052                 if (fgets(cmdline, sizeof(cmdline), f) != NULL) {
1053                         char *pos;
1054
1055                         pos = strstr(cmdline, "udev.log-priority=");
1056                         if (pos != NULL) {
1057                                 pos += strlen("udev.log-priority=");
1058                                 udev_set_log_priority(udev, util_log_priority(pos));
1059                         }
1060
1061                         pos = strstr(cmdline, "udev.children-max=");
1062                         if (pos != NULL) {
1063                                 pos += strlen("udev.children-max=");
1064                                 children_max = strtoul(pos, NULL, 0);
1065                         }
1066
1067                         pos = strstr(cmdline, "udev.exec-delay=");
1068                         if (pos != NULL) {
1069                                 pos += strlen("udev.exec-delay=");
1070                                 exec_delay = strtoul(pos, NULL, 0);
1071                         }
1072                 }
1073                 fclose(f);
1074         }
1075
1076         /* make sure std{in,out,err} fds are in a sane state */
1077         fd = open("/dev/null", O_RDWR);
1078         if (fd < 0) {
1079                 fprintf(stderr, "cannot open /dev/null\n");
1080                 err(udev, "cannot open /dev/null\n");
1081         }
1082         if (write(STDOUT_FILENO, 0, 0) < 0)
1083                 dup2(fd, STDOUT_FILENO);
1084         if (write(STDERR_FILENO, 0, 0) < 0)
1085                 dup2(fd, STDERR_FILENO);
1086
1087         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
1088         if (udev_ctrl == NULL) {
1089                 fprintf(stderr, "error initializing control socket");
1090                 err(udev, "error initializing udevd socket");
1091                 rc = 1;
1092                 goto exit;
1093         }
1094         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
1095                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
1096                 err(udev, "error binding control socket, seems udevd is already running\n");
1097                 rc = 1;
1098                 goto exit;
1099         }
1100         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
1101
1102         monitor = udev_monitor_new_from_netlink(udev, "kernel");
1103         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
1104                 fprintf(stderr, "error initializing netlink socket\n");
1105                 err(udev, "error initializing netlink socket\n");
1106                 rc = 3;
1107                 goto exit;
1108         }
1109         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
1110         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
1111
1112         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
1113         if (pfd[FD_INOTIFY].fd < 0) {
1114                 fprintf(stderr, "error initializing inotify\n");
1115                 err(udev, "error initializing inotify\n");
1116                 rc = 4;
1117                 goto exit;
1118         }
1119
1120         if (udev_get_rules_path(udev) != NULL) {
1121                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
1122                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1123         } else {
1124                 char filename[UTIL_PATH_SIZE];
1125                 struct stat statbuf;
1126
1127                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
1128                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1129                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
1130                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1131
1132                 /* watch dynamic rules directory */
1133                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
1134                 if (stat(filename, &statbuf) != 0) {
1135                         util_create_path(udev, filename);
1136                         udev_selinux_setfscreatecon(udev, filename, S_IFDIR|0755);
1137                         mkdir(filename, 0755);
1138                         udev_selinux_resetfscreatecon(udev);
1139                 }
1140                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
1141                                   IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1142         }
1143         udev_watch_restore(udev);
1144
1145         /* block and listen to all signals on signalfd */
1146         sigfillset(&mask);
1147         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
1148         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
1149         if (pfd[FD_SIGNAL].fd < 0) {
1150                 fprintf(stderr, "error getting signalfd\n");
1151                 err(udev, "error getting signalfd\n");
1152                 rc = 5;
1153                 goto exit;
1154         }
1155
1156         /* unnamed socket from workers to the main daemon */
1157         if (socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, worker_watch) < 0) {
1158                 fprintf(stderr, "error getting socketpair\n");
1159                 err(udev, "error getting socketpair\n");
1160                 rc = 6;
1161                 goto exit;
1162         }
1163         pfd[FD_WORKER].fd = worker_watch[READ_END];
1164
1165         rules = udev_rules_new(udev, resolve_names);
1166         if (rules == NULL) {
1167                 err(udev, "error reading rules\n");
1168                 goto exit;
1169         }
1170
1171         udev_queue_export = udev_queue_export_new(udev);
1172         if (udev_queue_export == NULL) {
1173                 err(udev, "error creating queue file\n");
1174                 goto exit;
1175         }
1176
1177         if (daemonize) {
1178                 pid_t pid;
1179
1180                 pid = fork();
1181                 switch (pid) {
1182                 case 0:
1183                         break;
1184                 case -1:
1185                         err(udev, "fork of daemon failed: %m\n");
1186                         rc = 4;
1187                         goto exit;
1188                 default:
1189                         rc = 0;
1190                         goto exit;
1191                 }
1192         }
1193
1194         f = fopen("/dev/kmsg", "w");
1195         if (f != NULL) {
1196                 fprintf(f, "<6>udev: starting version " VERSION "\n");
1197                 fclose(f);
1198         }
1199
1200         if (!debug) {
1201                 dup2(fd, STDIN_FILENO);
1202                 dup2(fd, STDOUT_FILENO);
1203                 dup2(fd, STDERR_FILENO);
1204         }
1205         if (fd > STDERR_FILENO)
1206                 close(fd);
1207
1208         /* set scheduling priority for the main daemon process */
1209         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1210
1211         chdir("/");
1212         umask(022);
1213         setsid();
1214
1215         /* OOM_DISABLE == -17 */
1216         fd = open("/proc/self/oom_adj", O_RDWR);
1217         if (fd < 0) {
1218                 err(udev, "error disabling OOM: %m\n");
1219         } else {
1220                 write(fd, "-17", 3);
1221                 close(fd);
1222         }
1223
1224         if (children_max <= 0) {
1225                 int memsize = mem_size_mb();
1226
1227                 /* set value depending on the amount of RAM */
1228                 if (memsize > 0)
1229                         children_max = 128 + (memsize / 8);
1230                 else
1231                         children_max = 128;
1232         }
1233         info(udev, "set children_max to %u\n", children_max);
1234
1235         static_dev_create(udev);
1236         static_dev_create_from_modules(udev);
1237         udev_rules_apply_static_dev_perms(rules);
1238
1239         udev_list_init(&event_list);
1240         udev_list_init(&worker_list);
1241
1242         while (!udev_exit) {
1243                 int fdcount;
1244                 int timeout;
1245
1246                 /* set timeout to kill idle workers */
1247                 if (udev_list_is_empty(&event_list) && children > 2)
1248                         timeout = 3 * 1000;
1249                 else
1250                         timeout = -1;
1251                 /* wait for events */
1252                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1253                 if (fdcount < 0)
1254                         continue;
1255
1256                 /* timeout - kill idle workers */
1257                 if (fdcount == 0)
1258                         worker_kill(udev, 2);
1259
1260                 /* event has finished */
1261                 if (pfd[FD_WORKER].revents & POLLIN)
1262                         worker_returned();
1263
1264                 /* get kernel uevent */
1265                 if (pfd[FD_NETLINK].revents & POLLIN) {
1266                         struct udev_device *dev;
1267
1268                         dev = udev_monitor_receive_device(monitor);
1269                         if (dev != NULL)
1270                                 event_queue_insert(dev);
1271                         else
1272                                 udev_device_unref(dev);
1273                 }
1274
1275                 /* start new events */
1276                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1277                         events_start(udev);
1278
1279                 /* get signal */
1280                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1281                         struct signalfd_siginfo fdsi;
1282                         ssize_t size;
1283
1284                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1285                         if (size == sizeof(struct signalfd_siginfo))
1286                                 handle_signal(udev, fdsi.ssi_signo);
1287                 }
1288
1289                 /* device node and rules directory inotify watch */
1290                 if (pfd[FD_INOTIFY].revents & POLLIN)
1291                         handle_inotify(udev);
1292
1293                 /*
1294                  * get control message
1295                  *
1296                  * This needs to be after the inotify handling, to make sure,
1297                  * that the settle signal is send back after the possibly generated
1298                  * "change" events by the inotify device node watch.
1299                  */
1300                 if (pfd[FD_CONTROL].revents & POLLIN)
1301                         handle_ctrl_msg(udev_ctrl);
1302
1303                 /* rules changed, set by inotify or a HUP signal */
1304                 if (reload_config) {
1305                         struct udev_rules *rules_new;
1306
1307                         worker_kill(udev, 0);
1308                         rules_new = udev_rules_new(udev, resolve_names);
1309                         if (rules_new != NULL) {
1310                                 udev_rules_unref(rules);
1311                                 rules = rules_new;
1312                         }
1313                         reload_config = 0;
1314                 }
1315         }
1316
1317         udev_queue_export_cleanup(udev_queue_export);
1318         rc = 0;
1319 exit:
1320         udev_queue_export_unref(udev_queue_export);
1321         udev_rules_unref(rules);
1322         udev_ctrl_unref(udev_ctrl);
1323         if (pfd[FD_SIGNAL].fd >= 0)
1324                 close(pfd[FD_SIGNAL].fd);
1325         if (worker_watch[READ_END] >= 0)
1326                 close(worker_watch[READ_END]);
1327         if (worker_watch[WRITE_END] >= 0)
1328                 close(worker_watch[WRITE_END]);
1329         udev_monitor_unref(monitor);
1330         udev_selinux_exit(udev);
1331         udev_unref(udev);
1332         udev_log_close();
1333         return rc;
1334 }