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