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                 udev_log_close();
 217                 udev_log_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                 udev_log_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                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 311                 break;
 312         }
 313 }
 314
 315 static void event_run(struct event *event)
 316 {
 317         struct udev_list_node *loop;
 318
 319         udev_list_node_foreach(loop, &worker_list) {
 320                 struct worker *worker = node_to_worker(loop);
 321                 ssize_t count;
 322
 323                 if (worker->state != WORKER_IDLE)
 324                         continue;
 325
 326                 worker->event = event;
 327                 worker->state = WORKER_RUNNING;
 328                 event->state = EVENT_RUNNING;
 329                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 330                 if (count < 0) {
 331                         err(event->udev, "worker [%u] did not accept message, kill it\n", worker->pid);
 332                         event->state = EVENT_QUEUED;
 333                         worker->state = WORKER_KILLED;
 334                         kill(worker->pid, SIGKILL);
 335                         continue;
 336                 }
 337                 return;
 338         }
 339
 340         if (childs >= max_childs) {
 341                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 342                 return;
 343         }
 344
 345         /* start new worker and pass initial device */
 346         worker_new(event);
 347 }
 348
 349 static void event_queue_insert(struct udev_device *dev)
 350 {
 351         struct event *event;
 352
 353         event = calloc(1, sizeof(struct event));
 354         if (event == NULL)
 355                 return;
 356
 357         event->udev = udev_device_get_udev(dev);
 358         event->dev = dev;
 359         event->seqnum = udev_device_get_seqnum(dev);
 360         event->devpath = udev_device_get_devpath(dev);
 361         event->devpath_len = strlen(event->devpath);
 362         event->devpath_old = udev_device_get_devpath_old(dev);
 363
 364         udev_queue_export_device_queued(udev_queue_export, dev);
 365         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 366              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 367
 368         event->state = EVENT_QUEUED;
 369         udev_list_node_append(&event->node, &event_list);
 370
 371         /* run all events with a timeout set immediately */
 372         if (udev_device_get_timeout(dev) > 0) {
 373                 worker_new(event);
 374                 return;
 375         }
 376 }
 377
 378 static void worker_kill(int retain)
 379 {
 380         struct udev_list_node *loop;
 381         int max;
 382
 383         if (childs <= retain)
 384                 return;
 385
 386         max = childs - retain;
 387
 388         udev_list_node_foreach(loop, &worker_list) {
 389                 struct worker *worker = node_to_worker(loop);
 390
 391                 if (max-- <= 0)
 392                         break;
 393
 394                 if (worker->state == WORKER_KILLED)
 395                         continue;
 396
 397                 worker->state = WORKER_KILLED;
 398                 kill(worker->pid, SIGTERM);
 399         }
 400 }
 401
 402 static int mem_size_mb(void)
 403 {
 404         FILE *f;
 405         char buf[4096];
 406         long int memsize = -1;
 407
 408         f = fopen("/proc/meminfo", "r");
 409         if (f == NULL)
 410                 return -1;
 411
 412         while (fgets(buf, sizeof(buf), f) != NULL) {
 413                 long int value;
 414
 415                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 416                         memsize = value / 1024;
 417                         break;
 418                 }
 419         }
 420
 421         fclose(f);
 422         return memsize;
 423 }
 424
 425 /* lookup event for identical, parent, child device */
 426 static int devpath_busy(struct event *event)
 427 {
 428         struct udev_list_node *loop;
 429         size_t common;
 430
 431         /* check if queue contains events we depend on */
 432         udev_list_node_foreach(loop, &event_list) {
 433                 struct event *loop_event = node_to_event(loop);
 434
 435                 /* we already found a later event, earlier can not block us, no need to check again */
 436                 if (loop_event->seqnum < event->delaying_seqnum)
 437                         continue;
 438
 439                 /* event we checked earlier still exists, no need to check again */
 440                 if (loop_event->seqnum == event->delaying_seqnum)
 441                         return 2;
 442
 443                 /* found ourself, no later event can block us */
 444                 if (loop_event->seqnum >= event->seqnum)
 445                         break;
 446
 447                 /* check our old name */
 448                 if (event->devpath_old != NULL)
 449                         if (strcmp(loop_event->devpath, event->devpath_old) == 0) {
 450                                 event->delaying_seqnum = loop_event->seqnum;
 451                                 return 3;
 452                         }
 453
 454                 /* compare devpath */
 455                 common = MIN(loop_event->devpath_len, event->devpath_len);
 456
 457                 /* one devpath is contained in the other? */
 458                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 459                         continue;
 460
 461                 /* identical device event found */
 462                 if (loop_event->devpath_len == event->devpath_len) {
 463                         event->delaying_seqnum = loop_event->seqnum;
 464                         return 4;
 465                 }
 466
 467                 /* parent device event found */
 468                 if (event->devpath[common] == '/') {
 469                         event->delaying_seqnum = loop_event->seqnum;
 470                         return 5;
 471                 }
 472
 473                 /* child device event found */
 474                 if (loop_event->devpath[common] == '/') {
 475                         event->delaying_seqnum = loop_event->seqnum;
 476                         return 6;
 477                 }
 478
 479                 /* no matching device */
 480                 continue;
 481         }
 482
 483         return 0;
 484 }
 485
 486 static void events_start(struct udev *udev)
 487 {
 488         struct udev_list_node *loop;
 489
 490         udev_list_node_foreach(loop, &event_list) {
 491                 struct event *event = node_to_event(loop);
 492
 493                 if (event->state != EVENT_QUEUED)
 494                         continue;
 495
 496                 /* do not start event if parent or child event is still running */
 497                 if (devpath_busy(event) != 0) {
 498                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 499                         continue;
 500                 }
 501
 502                 event_run(event);
 503         }
 504 }
 505
 506 static void worker_returned(void)
 507 {
 508         while (1) {
 509                 struct worker_message msg;
 510                 ssize_t size;
 511                 struct udev_list_node *loop;
 512
 513                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 514                 if (size != sizeof(struct worker_message))
 515                         break;
 516
 517                 /* lookup worker who sent the signal */
 518                 udev_list_node_foreach(loop, &worker_list) {
 519                         struct worker *worker = node_to_worker(loop);
 520
 521                         if (worker->pid != msg.pid)
 522                                 continue;
 523
 524                         /* worker returned */
 525                         worker->event->exitcode = msg.exitcode;
 526                         event_queue_delete(worker->event);
 527                         worker->event = NULL;
 528                         worker->state = WORKER_IDLE;
 529                         break;
 530                 }
 531         }
 532 }
 533
 534 /* receive the udevd message from userspace */
 535 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 536 {
 537         struct udev *udev = udev_ctrl_get_udev(uctrl);
 538         struct udev_ctrl_msg *ctrl_msg;
 539         const char *str;
 540         int i;
 541
 542         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 543         if (ctrl_msg == NULL)
 544                 return;
 545
 546         i = udev_ctrl_get_set_log_level(ctrl_msg);
 547         if (i >= 0) {
 548                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 549                 udev_set_log_priority(udev, i);
 550                 worker_kill(0);
 551         }
 552
 553         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 554                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 555                 stop_exec_queue = 1;
 556         }
 557
 558         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 559                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 560                 stop_exec_queue = 0;
 561         }
 562
 563         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 564                 info(udev, "udevd message (RELOAD_RULES) received\n");
 565                 reload_config = 1;
 566         }
 567
 568         str = udev_ctrl_get_set_env(ctrl_msg);
 569         if (str != NULL) {
 570                 char *key;
 571
 572                 key = strdup(str);
 573                 if (key != NULL) {
 574                         char *val;
 575
 576                         val = strchr(key, '=');
 577                         if (val != NULL) {
 578                                 val[0] = '\0';
 579                                 val = &val[1];
 580                                 if (val[0] == '\0') {
 581                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 582                                         udev_add_property(udev, key, NULL);
 583                                 } else {
 584                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 585                                         udev_add_property(udev, key, val);
 586                                 }
 587                         } else {
 588                                 err(udev, "wrong key format '%s'\n", key);
 589                         }
 590                         free(key);
 591                 }
 592                 worker_kill(0);
 593         }
 594
 595         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 596         if (i >= 0) {
 597                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 598                 max_childs = i;
 599         }
 600
 601         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 602         if (settle_pid > 0) {
 603                 info(udev, "udevd message (SETTLE) received\n");
 604                 kill(settle_pid, SIGUSR1);
 605                 settle_pid = 0;
 606         }
 607         udev_ctrl_msg_unref(ctrl_msg);
 608 }
 609
 610 /* read inotify messages */
 611 static int handle_inotify(struct udev *udev)
 612 {
 613         ssize_t nbytes, pos;
 614         char *buf;
 615         struct inotify_event *ev;
 616
 617         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 618                 return 0;
 619
 620         buf = malloc(nbytes);
 621         if (buf == NULL) {
 622                 err(udev, "error getting buffer for inotify\n");
 623                 return -1;
 624         }
 625
 626         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 627
 628         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 629                 struct udev_device *dev;
 630
 631                 ev = (struct inotify_event *)(buf + pos);
 632                 if (ev->len) {
 633                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 634                         reload_config = 1;
 635                         continue;
 636                 }
 637
 638                 dev = udev_watch_lookup(udev, ev->wd);
 639                 if (dev != NULL) {
 640                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 641                         if (ev->mask & IN_CLOSE_WRITE) {
 642                                 char filename[UTIL_PATH_SIZE];
 643                                 int fd;
 644
 645                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 646                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 647                                 fd = open(filename, O_WRONLY);
 648                                 if (fd < 0 || write(fd, "change", 6) < 0)
 649                                         info(udev, "error writing uevent: %m\n");
 650                                 close(fd);
 651                         }
 652                         if (ev->mask & IN_IGNORED)
 653                                 udev_watch_end(udev, dev);
 654
 655                         udev_device_unref(dev);
 656                 }
 657
 658         }
 659
 660         free(buf);
 661         return 0;
 662 }
 663
 664 static void handle_signal(struct udev *udev, int signo)
 665 {
 666         switch (signo) {
 667         case SIGINT:
 668         case SIGTERM:
 669                 udev_exit = 1;
 670                 break;
 671         case SIGCHLD:
 672                 while (1) {
 673                         pid_t pid;
 674                         int status;
 675                         struct udev_list_node *loop, *tmp;
 676
 677                         pid = waitpid(-1, &status, WNOHANG);
 678                         if (pid <= 0)
 679                                 break;
 680
 681                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 682                                 struct worker *worker = node_to_worker(loop);
 683
 684                                 if (worker->pid != pid)
 685                                         continue;
 686
 687                                 /* fail event, if worker died unexpectedly */
 688                                 if (worker->event != NULL) {
 689                                         int exitcode;
 690
 691                                         if (WIFEXITED(status))
 692                                                 exitcode = WEXITSTATUS(status);
 693                                         else if (WIFSIGNALED(status))
 694                                                 exitcode = WTERMSIG(status) + 128;
 695                                         else
 696                                                 exitcode = 0;
 697                                         worker->event->exitcode = exitcode;
 698                                         err(udev, "worker [%u] unexpectedly returned with %i\n", pid, exitcode);
 699                                         event_queue_delete(worker->event);
 700                                 }
 701
 702                                 udev_list_node_remove(&worker->node);
 703                                 worker_unref(worker);
 704                                 childs--;
 705                                 info(udev, "worker [%u] exit\n", pid);
 706                                 break;
 707                         }
 708                 }
 709                 break;
 710         case SIGHUP:
 711                 reload_config = 1;
 712                 break;
 713         }
 714 }
 715
 716 static void startup_log(struct udev *udev)
 717 {
 718         FILE *f;
 719         char path[UTIL_PATH_SIZE];
 720         struct stat statbuf;
 721
 722         f = fopen("/dev/kmsg", "w");
 723         if (f != NULL)
 724                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 725
 726         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 727         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 728                 const char *depr_str =
 729                         "udev: missing sysfs features; please update the kernel "
 730                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 731                         "udev may fail to work correctly";
 732
 733                 if (f != NULL)
 734                         fprintf(f, "<3>%s\n", depr_str);
 735                 err(udev, "%s\n", depr_str);
 736                 sleep(3);
 737         }
 738
 739         if (f != NULL)
 740                 fclose(f);
 741 }
 742
 743 int main(int argc, char *argv[])
 744 {
 745         struct udev *udev;
 746         int fd;
 747         sigset_t mask;
 748         const char *value;
 749         int daemonize = 0;
 750         int resolve_names = 1;
 751         static const struct option options[] = {
 752                 { "daemon", no_argument, NULL, 'd' },
 753                 { "debug-trace", no_argument, NULL, 't' },
 754                 { "debug", no_argument, NULL, 'D' },
 755                 { "help", no_argument, NULL, 'h' },
 756                 { "version", no_argument, NULL, 'V' },
 757                 { "resolve-names", required_argument, NULL, 'N' },
 758                 {}
 759         };
 760         int rc = 1;
 761
 762         udev = udev_new();
 763         if (udev == NULL)
 764                 goto exit;
 765
 766         udev_log_init("udevd");
 767         udev_set_log_fn(udev, log_fn);
 768         info(udev, "version %s\n", VERSION);
 769         udev_selinux_init(udev);
 770
 771         while (1) {
 772                 int option;
 773
 774                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 775                 if (option == -1)
 776                         break;
 777
 778                 switch (option) {
 779                 case 'd':
 780                         daemonize = 1;
 781                         break;
 782                 case 't':
 783                         debug_trace = 1;
 784                         break;
 785                 case 'D':
 786                         debug = 1;
 787                         if (udev_get_log_priority(udev) < LOG_INFO)
 788                                 udev_set_log_priority(udev, LOG_INFO);
 789                         break;
 790                 case 'N':
 791                         if (strcmp (optarg, "early") == 0) {
 792                                 resolve_names = 1;
 793                         } else if (strcmp (optarg, "late") == 0) {
 794                                 resolve_names = 0;
 795                         } else if (strcmp (optarg, "never") == 0) {
 796                                 resolve_names = -1;
 797                         } else {
 798                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 799                                 err(udev, "resolve-names must be early, late or never\n");
 800                                 goto exit;
 801                         }
 802                         break;
 803                 case 'h':
 804                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 805                                "[--resolve-names=early|late|never] [--version]\n");
 806                         goto exit;
 807                 case 'V':
 808                         printf("%s\n", VERSION);
 809                         goto exit;
 810                 default:
 811                         goto exit;
 812                 }
 813         }
 814
 815         if (getuid() != 0) {
 816                 fprintf(stderr, "root privileges required\n");
 817                 err(udev, "root privileges required\n");
 818                 goto exit;
 819         }
 820
 821         /* make sure std{in,out,err} fd's are in a sane state */
 822         fd = open("/dev/null", O_RDWR);
 823         if (fd < 0) {
 824                 fprintf(stderr, "cannot open /dev/null\n");
 825                 err(udev, "cannot open /dev/null\n");
 826         }
 827         if (write(STDOUT_FILENO, 0, 0) < 0)
 828                 dup2(fd, STDOUT_FILENO);
 829         if (write(STDERR_FILENO, 0, 0) < 0)
 830                 dup2(fd, STDERR_FILENO);
 831
 832         /* init control socket, bind() ensures, that only one udevd instance is running */
 833         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 834         if (udev_ctrl == NULL) {
 835                 fprintf(stderr, "error initializing control socket");
 836                 err(udev, "error initializing udevd socket");
 837                 rc = 1;
 838                 goto exit;
 839         }
 840         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 841                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 842                 err(udev, "error binding control socket, seems udevd is already running\n");
 843                 rc = 1;
 844                 goto exit;
 845         }
 846         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 847
 848         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 849         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 850                 fprintf(stderr, "error initializing netlink socket\n");
 851                 err(udev, "error initializing netlink socket\n");
 852                 rc = 3;
 853                 goto exit;
 854         }
 855         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 856         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 857
 858         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 859         if (pfd[FD_INOTIFY].fd < 0) {
 860                 fprintf(stderr, "error initializing inotify\n");
 861                 err(udev, "error initializing inotify\n");
 862                 rc = 4;
 863                 goto exit;
 864         }
 865
 866         if (udev_get_rules_path(udev) != NULL) {
 867                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 868                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 869         } else {
 870                 char filename[UTIL_PATH_SIZE];
 871
 872                 inotify_add_watch(pfd[FD_INOTIFY].fd, UDEV_PREFIX "/lib/udev/rules.d",
 873                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 874                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 875                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 876
 877                 /* watch dynamic rules directory */
 878                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 879                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 880                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 881         }
 882         udev_watch_restore(udev);
 883
 884         /* block and listen to all signals on signalfd */
 885         sigfillset(&mask);
 886         sigprocmask(SIG_SETMASK, &mask, NULL);
 887         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 888         if (pfd[FD_SIGNAL].fd < 0) {
 889                 fprintf(stderr, "error getting signalfd\n");
 890                 err(udev, "error getting signalfd\n");
 891                 rc = 5;
 892                 goto exit;
 893         }
 894
 895         /* unnamed socket from workers to the main daemon */
 896         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 897                 fprintf(stderr, "error getting socketpair\n");
 898                 err(udev, "error getting socketpair\n");
 899                 rc = 6;
 900                 goto exit;
 901         }
 902         pfd[FD_WORKER].fd = worker_watch[READ_END];
 903         util_set_fd_cloexec(worker_watch[WRITE_END]);
 904
 905         rules = udev_rules_new(udev, resolve_names);
 906         if (rules == NULL) {
 907                 err(udev, "error reading rules\n");
 908                 goto exit;
 909         }
 910
 911         udev_queue_export = udev_queue_export_new(udev);
 912         if (udev_queue_export == NULL) {
 913                 err(udev, "error creating queue file\n");
 914                 goto exit;
 915         }
 916
 917         if (daemonize) {
 918                 pid_t pid;
 919
 920                 pid = fork();
 921                 switch (pid) {
 922                 case 0:
 923                         break;
 924                 case -1:
 925                         err(udev, "fork of daemon failed: %m\n");
 926                         rc = 4;
 927                         goto exit;
 928                 default:
 929                         rc = 0;
 930                         goto exit;
 931                 }
 932         }
 933
 934         startup_log(udev);
 935
 936         /* redirect std{out,err} */
 937         if (!debug && !debug_trace) {
 938                 dup2(fd, STDIN_FILENO);
 939                 dup2(fd, STDOUT_FILENO);
 940                 dup2(fd, STDERR_FILENO);
 941         }
 942         if (fd > STDERR_FILENO)
 943                 close(fd);
 944
 945         /* set scheduling priority for the daemon */
 946         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 947
 948         chdir("/");
 949         umask(022);
 950         setsid();
 951
 952         /* OOM_DISABLE == -17 */
 953         fd = open("/proc/self/oom_adj", O_RDWR);
 954         if (fd < 0) {
 955                 err(udev, "error disabling OOM: %m\n");
 956         } else {
 957                 write(fd, "-17", 3);
 958                 close(fd);
 959         }
 960
 961         /* in trace mode run one event after the other */
 962         if (debug_trace) {
 963                 max_childs = 1;
 964         } else {
 965                 int memsize = mem_size_mb();
 966
 967                 if (memsize > 0)
 968                         max_childs = 128 + (memsize / 8);
 969                 else
 970                         max_childs = 128;
 971         }
 972
 973         /* possibly overwrite maximum limit of executed events */
 974         value = getenv("UDEVD_MAX_CHILDS");
 975         if (value)
 976                 max_childs = strtoul(value, NULL, 10);
 977         info(udev, "initialize max_childs to %u\n", max_childs);
 978
 979         udev_list_init(&event_list);
 980         udev_list_init(&worker_list);
 981
 982         while (!udev_exit) {
 983                 int fdcount;
 984                 int timeout;
 985
 986                 /* set timeout to kill idle workers */
 987                 if (udev_list_is_empty(&event_list) && childs > 2)
 988                         timeout = 3 * 1000;
 989                 else
 990                         timeout = -1;
 991                 /* wait for events */
 992                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
 993                 if (fdcount < 0)
 994                         continue;
 995
 996                 /* timeout - kill idle workers */
 997                 if (fdcount == 0)
 998                         worker_kill(2);
 999
1000                 /* event has finished */
1001                 if (pfd[FD_WORKER].revents & POLLIN)
1002                         worker_returned();
1003
1004                 /* get kernel uevent */
1005                 if (pfd[FD_NETLINK].revents & POLLIN) {
1006                         struct udev_device *dev;
1007
1008                         dev = udev_monitor_receive_device(monitor);
1009                         if (dev != NULL)
1010                                 event_queue_insert(dev);
1011                         else
1012                                 udev_device_unref(dev);
1013                 }
1014
1015                 /* start new events */
1016                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1017                         events_start(udev);
1018
1019                 /* get signal */
1020                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1021                         struct signalfd_siginfo fdsi;
1022                         ssize_t size;
1023
1024                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1025                         if (size == sizeof(struct signalfd_siginfo))
1026                                 handle_signal(udev, fdsi.ssi_signo);
1027                 }
1028
1029                 /* device node and rules directory inotify watch */
1030                 if (pfd[FD_INOTIFY].revents & POLLIN)
1031                         handle_inotify(udev);
1032
1033                 /*
1034                  * get control message
1035                  *
1036                  * This needs to be after the inotify handling, to make sure,
1037                  * that the settle signal is send back after the possibly generated
1038                  * "change" events by the inotify device node watch.
1039                  */
1040                 if (pfd[FD_CONTROL].revents & POLLIN)
1041                         handle_ctrl_msg(udev_ctrl);
1042
1043                 /* rules changed, set by inotify or a HUP signal */
1044                 if (reload_config) {
1045                         struct udev_rules *rules_new;
1046
1047                         worker_kill(0);
1048                         rules_new = udev_rules_new(udev, resolve_names);
1049                         if (rules_new != NULL) {
1050                                 udev_rules_unref(rules);
1051                                 rules = rules_new;
1052                         }
1053                         reload_config = 0;
1054                 }
1055         }
1056
1057         udev_queue_export_cleanup(udev_queue_export);
1058         rc = 0;
1059 exit:
1060         udev_queue_export_unref(udev_queue_export);
1061         udev_rules_unref(rules);
1062         udev_ctrl_unref(udev_ctrl);
1063         if (pfd[FD_SIGNAL].fd >= 0)
1064                 close(pfd[FD_SIGNAL].fd);
1065         if (worker_watch[READ_END] >= 0)
1066                 close(worker_watch[READ_END]);
1067         if (worker_watch[WRITE_END] >= 0)
1068                 close(worker_watch[WRITE_END]);
1069         udev_monitor_unref(monitor);
1070         udev_selinux_exit(udev);
1071         udev_unref(udev);
1072         udev_log_close();
1073         return rc;
1074 }