udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2009 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  * Copyright (C) 2009 Canonical Ltd.
   5  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stdbool.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <fcntl.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <dirent.h>
  34 #include <sys/time.h>
  35 #include <sys/prctl.h>
  36 #include <sys/socket.h>
  37 #include <sys/signalfd.h>
  38 #include <sys/select.h>
  39 #include <sys/poll.h>
  40 #include <sys/wait.h>
  41 #include <sys/stat.h>
  42 #include <sys/ioctl.h>
  43 #include <sys/inotify.h>
  44
  45 #include "udev.h"
  46
  47 #define UDEVD_PRIORITY                  -4
  48 #define UDEV_PRIORITY                   -2
  49
  50 static bool debug;
  51
  52 static void log_fn(struct udev *udev, int priority,
  53                    const char *file, int line, const char *fn,
  54                    const char *format, va_list args)
  55 {
  56         if (debug) {
  57                 char buf[1024];
  58                 struct timeval tv;
  59                 struct timezone tz;
  60
  61                 vsnprintf(buf, sizeof(buf), format, args);
  62                 gettimeofday(&tv, &tz);
  63                 fprintf(stderr, "%llu.%06u [%u] %s: %s",
  64                         (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
  65                         (int) getpid(), fn, buf);
  66         } else {
  67                 vsyslog(priority, format, args);
  68         }
  69 }
  70
  71 static bool debug_trace;
  72 static struct udev_rules *rules;
  73 static struct udev_queue_export *udev_queue_export;
  74 static struct udev_ctrl *udev_ctrl;
  75 static struct udev_monitor *monitor;
  76 static int worker_watch[2];
  77 static pid_t settle_pid;
  78 static bool stop_exec_queue;
  79 static bool reload_config;
  80 static int max_childs;
  81 static int childs;
  82 static sigset_t orig_sigmask;
  83 static struct udev_list_node event_list;
  84 static struct udev_list_node worker_list;
  85 static bool udev_exit;
  86 static volatile sig_atomic_t worker_exit;
  87
  88 enum poll_fd {
  89         FD_CONTROL,
  90         FD_NETLINK,
  91         FD_INOTIFY,
  92         FD_SIGNAL,
  93         FD_WORKER,
  94 };
  95
  96 static struct pollfd pfd[] = {
  97         [FD_NETLINK] = { .events = POLLIN },
  98         [FD_WORKER] =  { .events = POLLIN },
  99         [FD_SIGNAL] =  { .events = POLLIN },
 100         [FD_INOTIFY] = { .events = POLLIN },
 101         [FD_CONTROL] = { .events = POLLIN },
 102 };
 103
 104 enum event_state {
 105         EVENT_UNDEF,
 106         EVENT_QUEUED,
 107         EVENT_RUNNING,
 108 };
 109
 110 struct event {
 111         struct udev_list_node node;
 112         struct udev *udev;
 113         struct udev_device *dev;
 114         enum event_state state;
 115         int exitcode;
 116         unsigned long long int delaying_seqnum;
 117         unsigned long long int seqnum;
 118         const char *devpath;
 119         size_t devpath_len;
 120         const char *devpath_old;
 121         dev_t devnum;
 122         bool is_block;
 123 };
 124
 125 static struct event *node_to_event(struct udev_list_node *node)
 126 {
 127         char *event;
 128
 129         event = (char *)node;
 130         event -= offsetof(struct event, node);
 131         return (struct event *)event;
 132 }
 133
 134 enum worker_state {
 135         WORKER_UNDEF,
 136         WORKER_RUNNING,
 137         WORKER_IDLE,
 138         WORKER_KILLED,
 139 };
 140
 141 struct worker {
 142         struct udev_list_node node;
 143         struct udev *udev;
 144         int refcount;
 145         pid_t pid;
 146         struct udev_monitor *monitor;
 147         enum worker_state state;
 148         struct event *event;
 149 };
 150
 151 /* passed from worker to main process */
 152 struct worker_message {
 153         pid_t pid;
 154         int exitcode;
 155 };
 156
 157 static struct worker *node_to_worker(struct udev_list_node *node)
 158 {
 159         char *worker;
 160
 161         worker = (char *)node;
 162         worker -= offsetof(struct worker, node);
 163         return (struct worker *)worker;
 164 }
 165
 166 static void event_queue_delete(struct event *event)
 167 {
 168         udev_list_node_remove(&event->node);
 169
 170         /* mark as failed, if "add" event returns non-zero */
 171         if (event->exitcode != 0 && strcmp(udev_device_get_action(event->dev), "add") == 0)
 172                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 173         else
 174                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 175
 176         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 177         udev_device_unref(event->dev);
 178         free(event);
 179 }
 180
 181 static void event_sig_handler(int signum)
 182 {
 183         switch (signum) {
 184         case SIGALRM:
 185                 _exit(1);
 186                 break;
 187         case SIGTERM:
 188                 worker_exit = true;
 189                 break;
 190         }
 191 }
 192
 193 static struct worker *worker_ref(struct worker *worker)
 194 {
 195         worker->refcount++;
 196         return worker;
 197 }
 198
 199 static void worker_unref(struct worker *worker)
 200 {
 201         worker->refcount--;
 202         if (worker->refcount > 0)
 203                 return;
 204
 205         udev_list_node_remove(&worker->node);
 206         udev_monitor_unref(worker->monitor);
 207         childs--;
 208         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 209         free(worker);
 210 }
 211
 212 static void worker_new(struct event *event)
 213 {
 214         struct worker *worker;
 215         struct udev_monitor *worker_monitor;
 216         pid_t pid;
 217         struct sigaction act;
 218
 219         /* listen for new events */
 220         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 221         if (worker_monitor == NULL)
 222                 return;
 223         /* allow the main daemon netlink address to send devices to the worker */
 224         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 225         udev_monitor_enable_receiving(worker_monitor);
 226         util_set_fd_cloexec(udev_monitor_get_fd(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                         /* execute RUN= */
 297                         if (err == 0 && !udev_event->ignore_device && udev_get_run(udev_event->udev))
 298                                 failed = udev_event_execute_run(udev_event,
 299                                                                 &orig_sigmask);
 300
 301                         /* reset alarm */
 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 back 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                 childs++;
 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)
 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 (childs >= max_childs) {
 393                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 394                 return;
 395         }
 396
 397         /* start new worker and pass initial device */
 398         worker_new(event);
 399 }
 400
 401 static void event_queue_insert(struct udev_device *dev)
 402 {
 403         struct event *event;
 404
 405         event = calloc(1, sizeof(struct event));
 406         if (event == NULL)
 407                 return;
 408
 409         event->udev = udev_device_get_udev(dev);
 410         event->dev = dev;
 411         event->seqnum = udev_device_get_seqnum(dev);
 412         event->devpath = udev_device_get_devpath(dev);
 413         event->devpath_len = strlen(event->devpath);
 414         event->devpath_old = udev_device_get_devpath_old(dev);
 415         event->devnum = udev_device_get_devnum(dev);
 416         event->is_block = (strcmp("block", udev_device_get_subsystem(dev)) == 0);
 417
 418         udev_queue_export_device_queued(udev_queue_export, dev);
 419         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 420              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 421
 422         event->state = EVENT_QUEUED;
 423         udev_list_node_append(&event->node, &event_list);
 424
 425         /* run all events with a timeout set immediately */
 426         if (udev_device_get_timeout(dev) > 0) {
 427                 worker_new(event);
 428                 return;
 429         }
 430 }
 431
 432 static void worker_kill(struct udev *udev, int retain)
 433 {
 434         struct udev_list_node *loop;
 435         int max;
 436
 437         if (childs <= retain)
 438                 return;
 439
 440         max = childs - retain;
 441
 442         udev_list_node_foreach(loop, &worker_list) {
 443                 struct worker *worker = node_to_worker(loop);
 444
 445                 if (max-- <= 0)
 446                         break;
 447
 448                 if (worker->state == WORKER_KILLED)
 449                         continue;
 450
 451                 worker->state = WORKER_KILLED;
 452                 kill(worker->pid, SIGTERM);
 453         }
 454 }
 455
 456 static int mem_size_mb(void)
 457 {
 458         FILE *f;
 459         char buf[4096];
 460         long int memsize = -1;
 461
 462         f = fopen("/proc/meminfo", "r");
 463         if (f == NULL)
 464                 return -1;
 465
 466         while (fgets(buf, sizeof(buf), f) != NULL) {
 467                 long int value;
 468
 469                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 470                         memsize = value / 1024;
 471                         break;
 472                 }
 473         }
 474
 475         fclose(f);
 476         return memsize;
 477 }
 478
 479 /* lookup event for identical, parent, child device */
 480 static bool is_devpath_busy(struct event *event)
 481 {
 482         struct udev_list_node *loop;
 483         size_t common;
 484
 485         /* check if queue contains events we depend on */
 486         udev_list_node_foreach(loop, &event_list) {
 487                 struct event *loop_event = node_to_event(loop);
 488
 489                 /* we already found a later event, earlier can not block us, no need to check again */
 490                 if (loop_event->seqnum < event->delaying_seqnum)
 491                         continue;
 492
 493                 /* event we checked earlier still exists, no need to check again */
 494                 if (loop_event->seqnum == event->delaying_seqnum)
 495                         return true;
 496
 497                 /* found ourself, no later event can block us */
 498                 if (loop_event->seqnum >= event->seqnum)
 499                         break;
 500
 501                 /* check major/minor */
 502                 if (major(event->devnum) != 0 && event->devnum == loop_event->devnum && event->is_block == loop_event->is_block)
 503                         return true;
 504
 505                 /* check our old name */
 506                 if (event->devpath_old != NULL && strcmp(loop_event->devpath, event->devpath_old) == 0) {
 507                         event->delaying_seqnum = loop_event->seqnum;
 508                         return true;
 509                 }
 510
 511                 /* compare devpath */
 512                 common = MIN(loop_event->devpath_len, event->devpath_len);
 513
 514                 /* one devpath is contained in the other? */
 515                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 516                         continue;
 517
 518                 /* identical device event found */
 519                 if (loop_event->devpath_len == event->devpath_len) {
 520                         event->delaying_seqnum = loop_event->seqnum;
 521                         return true;
 522                 }
 523
 524                 /* parent device event found */
 525                 if (event->devpath[common] == '/') {
 526                         event->delaying_seqnum = loop_event->seqnum;
 527                         return true;
 528                 }
 529
 530                 /* child device event found */
 531                 if (loop_event->devpath[common] == '/') {
 532                         event->delaying_seqnum = loop_event->seqnum;
 533                         return true;
 534                 }
 535
 536                 /* no matching device */
 537                 continue;
 538         }
 539
 540         return false;
 541 }
 542
 543 static void events_start(struct udev *udev)
 544 {
 545         struct udev_list_node *loop;
 546
 547         udev_list_node_foreach(loop, &event_list) {
 548                 struct event *event = node_to_event(loop);
 549
 550                 if (event->state != EVENT_QUEUED)
 551                         continue;
 552
 553                 /* do not start event if parent or child event is still running */
 554                 if (is_devpath_busy(event)) {
 555                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 556                         continue;
 557                 }
 558
 559                 event_run(event);
 560         }
 561 }
 562
 563 static void worker_returned(void)
 564 {
 565         while (1) {
 566                 struct worker_message msg;
 567                 ssize_t size;
 568                 struct udev_list_node *loop;
 569
 570                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 571                 if (size != sizeof(struct worker_message))
 572                         break;
 573
 574                 /* lookup worker who sent the signal */
 575                 udev_list_node_foreach(loop, &worker_list) {
 576                         struct worker *worker = node_to_worker(loop);
 577
 578                         if (worker->pid != msg.pid)
 579                                 continue;
 580
 581                         /* worker returned */
 582                         worker->event->exitcode = msg.exitcode;
 583                         event_queue_delete(worker->event);
 584                         worker->event = NULL;
 585                         if (worker->state != WORKER_KILLED)
 586                                 worker->state = WORKER_IDLE;
 587                         worker_unref(worker);
 588                         break;
 589                 }
 590         }
 591 }
 592
 593 /* receive the udevd message from userspace */
 594 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 595 {
 596         struct udev *udev = udev_ctrl_get_udev(uctrl);
 597         struct udev_ctrl_msg *ctrl_msg;
 598         const char *str;
 599         int i;
 600
 601         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 602         if (ctrl_msg == NULL)
 603                 return;
 604
 605         i = udev_ctrl_get_set_log_level(ctrl_msg);
 606         if (i >= 0) {
 607                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 608                 udev_set_log_priority(udev, i);
 609                 worker_kill(udev, 0);
 610         }
 611
 612         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 613                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 614                 stop_exec_queue = true;
 615         }
 616
 617         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 618                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 619                 stop_exec_queue = false;
 620         }
 621
 622         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 623                 info(udev, "udevd message (RELOAD_RULES) received\n");
 624                 reload_config = true;
 625         }
 626
 627         str = udev_ctrl_get_set_env(ctrl_msg);
 628         if (str != NULL) {
 629                 char *key;
 630
 631                 key = strdup(str);
 632                 if (key != NULL) {
 633                         char *val;
 634
 635                         val = strchr(key, '=');
 636                         if (val != NULL) {
 637                                 val[0] = '\0';
 638                                 val = &val[1];
 639                                 if (val[0] == '\0') {
 640                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 641                                         udev_add_property(udev, key, NULL);
 642                                 } else {
 643                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 644                                         udev_add_property(udev, key, val);
 645                                 }
 646                         } else {
 647                                 err(udev, "wrong key format '%s'\n", key);
 648                         }
 649                         free(key);
 650                 }
 651                 worker_kill(udev, 0);
 652         }
 653
 654         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 655         if (i >= 0) {
 656                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 657                 max_childs = i;
 658         }
 659
 660         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 661         if (settle_pid > 0) {
 662                 info(udev, "udevd message (SETTLE) received\n");
 663                 kill(settle_pid, SIGUSR1);
 664                 settle_pid = 0;
 665         }
 666         udev_ctrl_msg_unref(ctrl_msg);
 667 }
 668
 669 /* read inotify messages */
 670 static int handle_inotify(struct udev *udev)
 671 {
 672         int nbytes, pos;
 673         char *buf;
 674         struct inotify_event *ev;
 675
 676         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 677                 return 0;
 678
 679         buf = malloc(nbytes);
 680         if (buf == NULL) {
 681                 err(udev, "error getting buffer for inotify\n");
 682                 return -1;
 683         }
 684
 685         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 686
 687         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 688                 struct udev_device *dev;
 689
 690                 ev = (struct inotify_event *)(buf + pos);
 691                 if (ev->len) {
 692                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 693                         reload_config = true;
 694                         continue;
 695                 }
 696
 697                 dev = udev_watch_lookup(udev, ev->wd);
 698                 if (dev != NULL) {
 699                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 700                         if (ev->mask & IN_CLOSE_WRITE) {
 701                                 char filename[UTIL_PATH_SIZE];
 702                                 int fd;
 703
 704                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 705                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 706                                 fd = open(filename, O_WRONLY);
 707                                 if (fd < 0 || write(fd, "change", 6) < 0)
 708                                         info(udev, "error writing uevent: %m\n");
 709                                 close(fd);
 710                         }
 711                         if (ev->mask & IN_IGNORED)
 712                                 udev_watch_end(udev, dev);
 713
 714                         udev_device_unref(dev);
 715                 }
 716
 717         }
 718
 719         free(buf);
 720         return 0;
 721 }
 722
 723 static void handle_signal(struct udev *udev, int signo)
 724 {
 725         switch (signo) {
 726         case SIGINT:
 727         case SIGTERM:
 728                 udev_exit = true;
 729                 break;
 730         case SIGCHLD:
 731                 while (1) {
 732                         pid_t pid;
 733                         int status;
 734                         struct udev_list_node *loop, *tmp;
 735
 736                         pid = waitpid(-1, &status, WNOHANG);
 737                         if (pid <= 0)
 738                                 break;
 739
 740                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 741                                 struct worker *worker = node_to_worker(loop);
 742
 743                                 if (worker->pid != pid)
 744                                         continue;
 745
 746                                 info(udev, "worker [%u] exit\n", pid);
 747                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 748                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 749                                         if (worker->event != NULL) {
 750                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 751                                                 worker->event->exitcode = -32;
 752                                                 event_queue_delete(worker->event);
 753                                                 /* drop reference from running event */
 754                                                 worker_unref(worker);
 755                                         }
 756                                 }
 757                                 worker_unref(worker);
 758                                 break;
 759                         }
 760                 }
 761                 break;
 762         case SIGHUP:
 763                 reload_config = true;
 764                 break;
 765         }
 766 }
 767
 768 static void startup_log(struct udev *udev)
 769 {
 770         FILE *f;
 771         char path[UTIL_PATH_SIZE];
 772         struct stat statbuf;
 773
 774         f = fopen("/dev/kmsg", "w");
 775         if (f != NULL)
 776                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 777
 778         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 779         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 780                 const char *depr_str =
 781                         "udev: missing sysfs features; please update the kernel "
 782                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 783                         "udev may fail to work correctly";
 784
 785                 if (f != NULL)
 786                         fprintf(f, "<3>%s\n", depr_str);
 787                 err(udev, "%s\n", depr_str);
 788                 sleep(15);
 789         }
 790
 791         if (f != NULL)
 792                 fclose(f);
 793 }
 794
 795 int main(int argc, char *argv[])
 796 {
 797         struct udev *udev;
 798         int fd;
 799         sigset_t mask;
 800         const char *value;
 801         int daemonize = false;
 802         int resolve_names = 1;
 803         static const struct option options[] = {
 804                 { "daemon", no_argument, NULL, 'd' },
 805                 { "debug-trace", no_argument, NULL, 't' },
 806                 { "debug", no_argument, NULL, 'D' },
 807                 { "help", no_argument, NULL, 'h' },
 808                 { "version", no_argument, NULL, 'V' },
 809                 { "resolve-names", required_argument, NULL, 'N' },
 810                 {}
 811         };
 812         int rc = 1;
 813
 814         udev = udev_new();
 815         if (udev == NULL)
 816                 goto exit;
 817
 818         udev_log_init("udevd");
 819         udev_set_log_fn(udev, log_fn);
 820         info(udev, "version %s\n", VERSION);
 821         udev_selinux_init(udev);
 822
 823         while (1) {
 824                 int option;
 825
 826                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 827                 if (option == -1)
 828                         break;
 829
 830                 switch (option) {
 831                 case 'd':
 832                         daemonize = true;
 833                         break;
 834                 case 't':
 835                         debug_trace = true;
 836                         break;
 837                 case 'D':
 838                         debug = true;
 839                         if (udev_get_log_priority(udev) < LOG_INFO)
 840                                 udev_set_log_priority(udev, LOG_INFO);
 841                         break;
 842                 case 'N':
 843                         if (strcmp (optarg, "early") == 0) {
 844                                 resolve_names = 1;
 845                         } else if (strcmp (optarg, "late") == 0) {
 846                                 resolve_names = 0;
 847                         } else if (strcmp (optarg, "never") == 0) {
 848                                 resolve_names = -1;
 849                         } else {
 850                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 851                                 err(udev, "resolve-names must be early, late or never\n");
 852                                 goto exit;
 853                         }
 854                         break;
 855                 case 'h':
 856                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 857                                "[--resolve-names=early|late|never] [--version]\n");
 858                         goto exit;
 859                 case 'V':
 860                         printf("%s\n", VERSION);
 861                         goto exit;
 862                 default:
 863                         goto exit;
 864                 }
 865         }
 866
 867         if (getuid() != 0) {
 868                 fprintf(stderr, "root privileges required\n");
 869                 err(udev, "root privileges required\n");
 870                 goto exit;
 871         }
 872
 873         /* make sure std{in,out,err} fd's are in a sane state */
 874         fd = open("/dev/null", O_RDWR);
 875         if (fd < 0) {
 876                 fprintf(stderr, "cannot open /dev/null\n");
 877                 err(udev, "cannot open /dev/null\n");
 878         }
 879         if (write(STDOUT_FILENO, 0, 0) < 0)
 880                 dup2(fd, STDOUT_FILENO);
 881         if (write(STDERR_FILENO, 0, 0) < 0)
 882                 dup2(fd, STDERR_FILENO);
 883
 884         /* init control socket, bind() ensures, that only one udevd instance is running */
 885         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 886         if (udev_ctrl == NULL) {
 887                 fprintf(stderr, "error initializing control socket");
 888                 err(udev, "error initializing udevd socket");
 889                 rc = 1;
 890                 goto exit;
 891         }
 892         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 893                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 894                 err(udev, "error binding control socket, seems udevd is already running\n");
 895                 rc = 1;
 896                 goto exit;
 897         }
 898         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 899
 900         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 901         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 902                 fprintf(stderr, "error initializing netlink socket\n");
 903                 err(udev, "error initializing netlink socket\n");
 904                 rc = 3;
 905                 goto exit;
 906         }
 907         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 908         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 909
 910         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 911         if (pfd[FD_INOTIFY].fd < 0) {
 912                 fprintf(stderr, "error initializing inotify\n");
 913                 err(udev, "error initializing inotify\n");
 914                 rc = 4;
 915                 goto exit;
 916         }
 917
 918         if (udev_get_rules_path(udev) != NULL) {
 919                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 920                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 921         } else {
 922                 char filename[UTIL_PATH_SIZE];
 923
 924                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 925                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 926                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 927                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 928
 929                 /* watch dynamic rules directory */
 930                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 931                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 932                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 933         }
 934         udev_watch_restore(udev);
 935
 936         /* block and listen to all signals on signalfd */
 937         sigfillset(&mask);
 938         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
 939         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 940         if (pfd[FD_SIGNAL].fd < 0) {
 941                 fprintf(stderr, "error getting signalfd\n");
 942                 err(udev, "error getting signalfd\n");
 943                 rc = 5;
 944                 goto exit;
 945         }
 946
 947         /* unnamed socket from workers to the main daemon */
 948         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 949                 fprintf(stderr, "error getting socketpair\n");
 950                 err(udev, "error getting socketpair\n");
 951                 rc = 6;
 952                 goto exit;
 953         }
 954         pfd[FD_WORKER].fd = worker_watch[READ_END];
 955         util_set_fd_cloexec(worker_watch[WRITE_END]);
 956
 957         rules = udev_rules_new(udev, resolve_names);
 958         if (rules == NULL) {
 959                 err(udev, "error reading rules\n");
 960                 goto exit;
 961         }
 962
 963         udev_queue_export = udev_queue_export_new(udev);
 964         if (udev_queue_export == NULL) {
 965                 err(udev, "error creating queue file\n");
 966                 goto exit;
 967         }
 968
 969         if (daemonize) {
 970                 pid_t pid;
 971
 972                 pid = fork();
 973                 switch (pid) {
 974                 case 0:
 975                         break;
 976                 case -1:
 977                         err(udev, "fork of daemon failed: %m\n");
 978                         rc = 4;
 979                         goto exit;
 980                 default:
 981                         rc = 0;
 982                         goto exit;
 983                 }
 984         }
 985
 986         startup_log(udev);
 987
 988         /* redirect std{out,err} */
 989         if (!debug && !debug_trace) {
 990                 dup2(fd, STDIN_FILENO);
 991                 dup2(fd, STDOUT_FILENO);
 992                 dup2(fd, STDERR_FILENO);
 993         }
 994         if (fd > STDERR_FILENO)
 995                 close(fd);
 996
 997         /* set scheduling priority for the daemon */
 998         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 999
1000         chdir("/");
1001         umask(022);
1002         setsid();
1003
1004         /* OOM_DISABLE == -17 */
1005         fd = open("/proc/self/oom_adj", O_RDWR);
1006         if (fd < 0) {
1007                 err(udev, "error disabling OOM: %m\n");
1008         } else {
1009                 write(fd, "-17", 3);
1010                 close(fd);
1011         }
1012
1013         /* in trace mode run one event after the other */
1014         if (debug_trace) {
1015                 max_childs = 1;
1016         } else {
1017                 int memsize = mem_size_mb();
1018
1019                 if (memsize > 0)
1020                         max_childs = 128 + (memsize / 8);
1021                 else
1022                         max_childs = 128;
1023         }
1024
1025         /* possibly overwrite maximum limit of executed events */
1026         value = getenv("UDEVD_MAX_CHILDS");
1027         if (value)
1028                 max_childs = strtoul(value, NULL, 10);
1029         info(udev, "initialize max_childs to %u\n", max_childs);
1030
1031         udev_list_init(&event_list);
1032         udev_list_init(&worker_list);
1033
1034         while (!udev_exit) {
1035                 int fdcount;
1036                 int timeout;
1037
1038                 /* set timeout to kill idle workers */
1039                 if (udev_list_is_empty(&event_list) && childs > 2)
1040                         timeout = 3 * 1000;
1041                 else
1042                         timeout = -1;
1043                 /* wait for events */
1044                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1045                 if (fdcount < 0)
1046                         continue;
1047
1048                 /* timeout - kill idle workers */
1049                 if (fdcount == 0)
1050                         worker_kill(udev, 2);
1051
1052                 /* event has finished */
1053                 if (pfd[FD_WORKER].revents & POLLIN)
1054                         worker_returned();
1055
1056                 /* get kernel uevent */
1057                 if (pfd[FD_NETLINK].revents & POLLIN) {
1058                         struct udev_device *dev;
1059
1060                         dev = udev_monitor_receive_device(monitor);
1061                         if (dev != NULL)
1062                                 event_queue_insert(dev);
1063                         else
1064                                 udev_device_unref(dev);
1065                 }
1066
1067                 /* start new events */
1068                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1069                         events_start(udev);
1070
1071                 /* get signal */
1072                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1073                         struct signalfd_siginfo fdsi;
1074                         ssize_t size;
1075
1076                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1077                         if (size == sizeof(struct signalfd_siginfo))
1078                                 handle_signal(udev, fdsi.ssi_signo);
1079                 }
1080
1081                 /* device node and rules directory inotify watch */
1082                 if (pfd[FD_INOTIFY].revents & POLLIN)
1083                         handle_inotify(udev);
1084
1085                 /*
1086                  * get control message
1087                  *
1088                  * This needs to be after the inotify handling, to make sure,
1089                  * that the settle signal is send back after the possibly generated
1090                  * "change" events by the inotify device node watch.
1091                  */
1092                 if (pfd[FD_CONTROL].revents & POLLIN)
1093                         handle_ctrl_msg(udev_ctrl);
1094
1095                 /* rules changed, set by inotify or a HUP signal */
1096                 if (reload_config) {
1097                         struct udev_rules *rules_new;
1098
1099                         worker_kill(udev, 0);
1100                         rules_new = udev_rules_new(udev, resolve_names);
1101                         if (rules_new != NULL) {
1102                                 udev_rules_unref(rules);
1103                                 rules = rules_new;
1104                         }
1105                         reload_config = 0;
1106                 }
1107         }
1108
1109         udev_queue_export_cleanup(udev_queue_export);
1110         rc = 0;
1111 exit:
1112         udev_queue_export_unref(udev_queue_export);
1113         udev_rules_unref(rules);
1114         udev_ctrl_unref(udev_ctrl);
1115         if (pfd[FD_SIGNAL].fd >= 0)
1116                 close(pfd[FD_SIGNAL].fd);
1117         if (worker_watch[READ_END] >= 0)
1118                 close(worker_watch[READ_END]);
1119         if (worker_watch[WRITE_END] >= 0)
1120                 close(worker_watch[WRITE_END]);
1121         udev_monitor_unref(monitor);
1122         udev_selinux_exit(udev);
1123         udev_unref(udev);
1124         udev_log_close();
1125         return rc;
1126 }