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                         event->state = EVENT_QUEUED;
 332                         worker->event = NULL;
 333                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 334                         worker->state = WORKER_KILLED;
 335                         kill(worker->pid, SIGKILL);
 336                         continue;
 337                 }
 338                 return;
 339         }
 340
 341         if (childs >= max_childs) {
 342                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 343                 return;
 344         }
 345
 346         /* start new worker and pass initial device */
 347         worker_new(event);
 348 }
 349
 350 static void event_queue_insert(struct udev_device *dev)
 351 {
 352         struct event *event;
 353
 354         event = calloc(1, sizeof(struct event));
 355         if (event == NULL)
 356                 return;
 357
 358         event->udev = udev_device_get_udev(dev);
 359         event->dev = dev;
 360         event->seqnum = udev_device_get_seqnum(dev);
 361         event->devpath = udev_device_get_devpath(dev);
 362         event->devpath_len = strlen(event->devpath);
 363         event->devpath_old = udev_device_get_devpath_old(dev);
 364
 365         udev_queue_export_device_queued(udev_queue_export, dev);
 366         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 367              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 368
 369         event->state = EVENT_QUEUED;
 370         udev_list_node_append(&event->node, &event_list);
 371
 372         /* run all events with a timeout set immediately */
 373         if (udev_device_get_timeout(dev) > 0) {
 374                 worker_new(event);
 375                 return;
 376         }
 377 }
 378
 379 static void worker_kill(int retain)
 380 {
 381         struct udev_list_node *loop;
 382         int max;
 383
 384         if (childs <= retain)
 385                 return;
 386
 387         max = childs - retain;
 388
 389         udev_list_node_foreach(loop, &worker_list) {
 390                 struct worker *worker = node_to_worker(loop);
 391
 392                 if (max-- <= 0)
 393                         break;
 394
 395                 if (worker->state == WORKER_KILLED)
 396                         continue;
 397
 398                 worker->state = WORKER_KILLED;
 399                 kill(worker->pid, SIGTERM);
 400         }
 401 }
 402
 403 static int mem_size_mb(void)
 404 {
 405         FILE *f;
 406         char buf[4096];
 407         long int memsize = -1;
 408
 409         f = fopen("/proc/meminfo", "r");
 410         if (f == NULL)
 411                 return -1;
 412
 413         while (fgets(buf, sizeof(buf), f) != NULL) {
 414                 long int value;
 415
 416                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 417                         memsize = value / 1024;
 418                         break;
 419                 }
 420         }
 421
 422         fclose(f);
 423         return memsize;
 424 }
 425
 426 /* lookup event for identical, parent, child device */
 427 static int devpath_busy(struct event *event)
 428 {
 429         struct udev_list_node *loop;
 430         size_t common;
 431
 432         /* check if queue contains events we depend on */
 433         udev_list_node_foreach(loop, &event_list) {
 434                 struct event *loop_event = node_to_event(loop);
 435
 436                 /* we already found a later event, earlier can not block us, no need to check again */
 437                 if (loop_event->seqnum < event->delaying_seqnum)
 438                         continue;
 439
 440                 /* event we checked earlier still exists, no need to check again */
 441                 if (loop_event->seqnum == event->delaying_seqnum)
 442                         return 2;
 443
 444                 /* found ourself, no later event can block us */
 445                 if (loop_event->seqnum >= event->seqnum)
 446                         break;
 447
 448                 /* check our old name */
 449                 if (event->devpath_old != NULL)
 450                         if (strcmp(loop_event->devpath, event->devpath_old) == 0) {
 451                                 event->delaying_seqnum = loop_event->seqnum;
 452                                 return 3;
 453                         }
 454
 455                 /* compare devpath */
 456                 common = MIN(loop_event->devpath_len, event->devpath_len);
 457
 458                 /* one devpath is contained in the other? */
 459                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 460                         continue;
 461
 462                 /* identical device event found */
 463                 if (loop_event->devpath_len == event->devpath_len) {
 464                         event->delaying_seqnum = loop_event->seqnum;
 465                         return 4;
 466                 }
 467
 468                 /* parent device event found */
 469                 if (event->devpath[common] == '/') {
 470                         event->delaying_seqnum = loop_event->seqnum;
 471                         return 5;
 472                 }
 473
 474                 /* child device event found */
 475                 if (loop_event->devpath[common] == '/') {
 476                         event->delaying_seqnum = loop_event->seqnum;
 477                         return 6;
 478                 }
 479
 480                 /* no matching device */
 481                 continue;
 482         }
 483
 484         return 0;
 485 }
 486
 487 static void events_start(struct udev *udev)
 488 {
 489         struct udev_list_node *loop;
 490
 491         udev_list_node_foreach(loop, &event_list) {
 492                 struct event *event = node_to_event(loop);
 493
 494                 if (event->state != EVENT_QUEUED)
 495                         continue;
 496
 497                 /* do not start event if parent or child event is still running */
 498                 if (devpath_busy(event) != 0) {
 499                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 500                         continue;
 501                 }
 502
 503                 event_run(event);
 504         }
 505 }
 506
 507 static void worker_returned(void)
 508 {
 509         while (1) {
 510                 struct worker_message msg;
 511                 ssize_t size;
 512                 struct udev_list_node *loop;
 513
 514                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 515                 if (size != sizeof(struct worker_message))
 516                         break;
 517
 518                 /* lookup worker who sent the signal */
 519                 udev_list_node_foreach(loop, &worker_list) {
 520                         struct worker *worker = node_to_worker(loop);
 521
 522                         if (worker->pid != msg.pid)
 523                                 continue;
 524
 525                         if (worker->state != WORKER_RUNNING)
 526                                 break;
 527
 528                         /* worker returned */
 529                         worker->event->exitcode = msg.exitcode;
 530                         event_queue_delete(worker->event);
 531                         worker->event = NULL;
 532                         worker->state = WORKER_IDLE;
 533                         break;
 534                 }
 535         }
 536 }
 537
 538 /* receive the udevd message from userspace */
 539 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 540 {
 541         struct udev *udev = udev_ctrl_get_udev(uctrl);
 542         struct udev_ctrl_msg *ctrl_msg;
 543         const char *str;
 544         int i;
 545
 546         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 547         if (ctrl_msg == NULL)
 548                 return;
 549
 550         i = udev_ctrl_get_set_log_level(ctrl_msg);
 551         if (i >= 0) {
 552                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 553                 udev_set_log_priority(udev, i);
 554                 worker_kill(0);
 555         }
 556
 557         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 558                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 559                 stop_exec_queue = 1;
 560         }
 561
 562         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 563                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 564                 stop_exec_queue = 0;
 565         }
 566
 567         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 568                 info(udev, "udevd message (RELOAD_RULES) received\n");
 569                 reload_config = 1;
 570         }
 571
 572         str = udev_ctrl_get_set_env(ctrl_msg);
 573         if (str != NULL) {
 574                 char *key;
 575
 576                 key = strdup(str);
 577                 if (key != NULL) {
 578                         char *val;
 579
 580                         val = strchr(key, '=');
 581                         if (val != NULL) {
 582                                 val[0] = '\0';
 583                                 val = &val[1];
 584                                 if (val[0] == '\0') {
 585                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 586                                         udev_add_property(udev, key, NULL);
 587                                 } else {
 588                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 589                                         udev_add_property(udev, key, val);
 590                                 }
 591                         } else {
 592                                 err(udev, "wrong key format '%s'\n", key);
 593                         }
 594                         free(key);
 595                 }
 596                 worker_kill(0);
 597         }
 598
 599         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 600         if (i >= 0) {
 601                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 602                 max_childs = i;
 603         }
 604
 605         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 606         if (settle_pid > 0) {
 607                 info(udev, "udevd message (SETTLE) received\n");
 608                 kill(settle_pid, SIGUSR1);
 609                 settle_pid = 0;
 610         }
 611         udev_ctrl_msg_unref(ctrl_msg);
 612 }
 613
 614 /* read inotify messages */
 615 static int handle_inotify(struct udev *udev)
 616 {
 617         ssize_t nbytes, pos;
 618         char *buf;
 619         struct inotify_event *ev;
 620
 621         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 622                 return 0;
 623
 624         buf = malloc(nbytes);
 625         if (buf == NULL) {
 626                 err(udev, "error getting buffer for inotify\n");
 627                 return -1;
 628         }
 629
 630         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 631
 632         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 633                 struct udev_device *dev;
 634
 635                 ev = (struct inotify_event *)(buf + pos);
 636                 if (ev->len) {
 637                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 638                         reload_config = 1;
 639                         continue;
 640                 }
 641
 642                 dev = udev_watch_lookup(udev, ev->wd);
 643                 if (dev != NULL) {
 644                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 645                         if (ev->mask & IN_CLOSE_WRITE) {
 646                                 char filename[UTIL_PATH_SIZE];
 647                                 int fd;
 648
 649                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 650                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 651                                 fd = open(filename, O_WRONLY);
 652                                 if (fd < 0 || write(fd, "change", 6) < 0)
 653                                         info(udev, "error writing uevent: %m\n");
 654                                 close(fd);
 655                         }
 656                         if (ev->mask & IN_IGNORED)
 657                                 udev_watch_end(udev, dev);
 658
 659                         udev_device_unref(dev);
 660                 }
 661
 662         }
 663
 664         free(buf);
 665         return 0;
 666 }
 667
 668 static void handle_signal(struct udev *udev, int signo)
 669 {
 670         switch (signo) {
 671         case SIGINT:
 672         case SIGTERM:
 673                 udev_exit = 1;
 674                 break;
 675         case SIGCHLD:
 676                 while (1) {
 677                         pid_t pid;
 678                         int status;
 679                         struct udev_list_node *loop, *tmp;
 680
 681                         pid = waitpid(-1, &status, WNOHANG);
 682                         if (pid <= 0)
 683                                 break;
 684
 685                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 686                                 struct worker *worker = node_to_worker(loop);
 687
 688                                 if (worker->pid != pid)
 689                                         continue;
 690
 691                                 /* fail event, if worker died unexpectedly */
 692                                 if (worker->event != NULL) {
 693                                         int exitcode;
 694
 695                                         if (WIFEXITED(status))
 696                                                 exitcode = WEXITSTATUS(status);
 697                                         else if (WIFSIGNALED(status))
 698                                                 exitcode = WTERMSIG(status) + 128;
 699                                         else
 700                                                 exitcode = 0;
 701                                         worker->event->exitcode = exitcode;
 702                                         err(udev, "worker [%u] unexpectedly returned with %i\n", pid, exitcode);
 703                                         event_queue_delete(worker->event);
 704                                 }
 705
 706                                 udev_list_node_remove(&worker->node);
 707                                 worker_unref(worker);
 708                                 childs--;
 709                                 info(udev, "worker [%u] exit\n", pid);
 710                                 break;
 711                         }
 712                 }
 713                 break;
 714         case SIGHUP:
 715                 reload_config = 1;
 716                 break;
 717         }
 718 }
 719
 720 static void startup_log(struct udev *udev)
 721 {
 722         FILE *f;
 723         char path[UTIL_PATH_SIZE];
 724         struct stat statbuf;
 725
 726         f = fopen("/dev/kmsg", "w");
 727         if (f != NULL)
 728                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 729
 730         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 731         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 732                 const char *depr_str =
 733                         "udev: missing sysfs features; please update the kernel "
 734                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 735                         "udev may fail to work correctly";
 736
 737                 if (f != NULL)
 738                         fprintf(f, "<3>%s\n", depr_str);
 739                 err(udev, "%s\n", depr_str);
 740                 sleep(3);
 741         }
 742
 743         if (f != NULL)
 744                 fclose(f);
 745 }
 746
 747 int main(int argc, char *argv[])
 748 {
 749         struct udev *udev;
 750         int fd;
 751         sigset_t mask;
 752         const char *value;
 753         int daemonize = 0;
 754         int resolve_names = 1;
 755         static const struct option options[] = {
 756                 { "daemon", no_argument, NULL, 'd' },
 757                 { "debug-trace", no_argument, NULL, 't' },
 758                 { "debug", no_argument, NULL, 'D' },
 759                 { "help", no_argument, NULL, 'h' },
 760                 { "version", no_argument, NULL, 'V' },
 761                 { "resolve-names", required_argument, NULL, 'N' },
 762                 {}
 763         };
 764         int rc = 1;
 765
 766         udev = udev_new();
 767         if (udev == NULL)
 768                 goto exit;
 769
 770         udev_log_init("udevd");
 771         udev_set_log_fn(udev, log_fn);
 772         info(udev, "version %s\n", VERSION);
 773         udev_selinux_init(udev);
 774
 775         while (1) {
 776                 int option;
 777
 778                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 779                 if (option == -1)
 780                         break;
 781
 782                 switch (option) {
 783                 case 'd':
 784                         daemonize = 1;
 785                         break;
 786                 case 't':
 787                         debug_trace = 1;
 788                         break;
 789                 case 'D':
 790                         debug = 1;
 791                         if (udev_get_log_priority(udev) < LOG_INFO)
 792                                 udev_set_log_priority(udev, LOG_INFO);
 793                         break;
 794                 case 'N':
 795                         if (strcmp (optarg, "early") == 0) {
 796                                 resolve_names = 1;
 797                         } else if (strcmp (optarg, "late") == 0) {
 798                                 resolve_names = 0;
 799                         } else if (strcmp (optarg, "never") == 0) {
 800                                 resolve_names = -1;
 801                         } else {
 802                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 803                                 err(udev, "resolve-names must be early, late or never\n");
 804                                 goto exit;
 805                         }
 806                         break;
 807                 case 'h':
 808                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 809                                "[--resolve-names=early|late|never] [--version]\n");
 810                         goto exit;
 811                 case 'V':
 812                         printf("%s\n", VERSION);
 813                         goto exit;
 814                 default:
 815                         goto exit;
 816                 }
 817         }
 818
 819         if (getuid() != 0) {
 820                 fprintf(stderr, "root privileges required\n");
 821                 err(udev, "root privileges required\n");
 822                 goto exit;
 823         }
 824
 825         /* make sure std{in,out,err} fd's are in a sane state */
 826         fd = open("/dev/null", O_RDWR);
 827         if (fd < 0) {
 828                 fprintf(stderr, "cannot open /dev/null\n");
 829                 err(udev, "cannot open /dev/null\n");
 830         }
 831         if (write(STDOUT_FILENO, 0, 0) < 0)
 832                 dup2(fd, STDOUT_FILENO);
 833         if (write(STDERR_FILENO, 0, 0) < 0)
 834                 dup2(fd, STDERR_FILENO);
 835
 836         /* init control socket, bind() ensures, that only one udevd instance is running */
 837         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 838         if (udev_ctrl == NULL) {
 839                 fprintf(stderr, "error initializing control socket");
 840                 err(udev, "error initializing udevd socket");
 841                 rc = 1;
 842                 goto exit;
 843         }
 844         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 845                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 846                 err(udev, "error binding control socket, seems udevd is already running\n");
 847                 rc = 1;
 848                 goto exit;
 849         }
 850         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 851
 852         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 853         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 854                 fprintf(stderr, "error initializing netlink socket\n");
 855                 err(udev, "error initializing netlink socket\n");
 856                 rc = 3;
 857                 goto exit;
 858         }
 859         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 860         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 861
 862         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 863         if (pfd[FD_INOTIFY].fd < 0) {
 864                 fprintf(stderr, "error initializing inotify\n");
 865                 err(udev, "error initializing inotify\n");
 866                 rc = 4;
 867                 goto exit;
 868         }
 869
 870         if (udev_get_rules_path(udev) != NULL) {
 871                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 872                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 873         } else {
 874                 char filename[UTIL_PATH_SIZE];
 875
 876                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 877                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 878                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 879                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 880
 881                 /* watch dynamic rules directory */
 882                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 883                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 884                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 885         }
 886         udev_watch_restore(udev);
 887
 888         /* block and listen to all signals on signalfd */
 889         sigfillset(&mask);
 890         sigprocmask(SIG_SETMASK, &mask, NULL);
 891         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 892         if (pfd[FD_SIGNAL].fd < 0) {
 893                 fprintf(stderr, "error getting signalfd\n");
 894                 err(udev, "error getting signalfd\n");
 895                 rc = 5;
 896                 goto exit;
 897         }
 898
 899         /* unnamed socket from workers to the main daemon */
 900         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 901                 fprintf(stderr, "error getting socketpair\n");
 902                 err(udev, "error getting socketpair\n");
 903                 rc = 6;
 904                 goto exit;
 905         }
 906         pfd[FD_WORKER].fd = worker_watch[READ_END];
 907         util_set_fd_cloexec(worker_watch[WRITE_END]);
 908
 909         rules = udev_rules_new(udev, resolve_names);
 910         if (rules == NULL) {
 911                 err(udev, "error reading rules\n");
 912                 goto exit;
 913         }
 914
 915         udev_queue_export = udev_queue_export_new(udev);
 916         if (udev_queue_export == NULL) {
 917                 err(udev, "error creating queue file\n");
 918                 goto exit;
 919         }
 920
 921         if (daemonize) {
 922                 pid_t pid;
 923
 924                 pid = fork();
 925                 switch (pid) {
 926                 case 0:
 927                         break;
 928                 case -1:
 929                         err(udev, "fork of daemon failed: %m\n");
 930                         rc = 4;
 931                         goto exit;
 932                 default:
 933                         rc = 0;
 934                         goto exit;
 935                 }
 936         }
 937
 938         startup_log(udev);
 939
 940         /* redirect std{out,err} */
 941         if (!debug && !debug_trace) {
 942                 dup2(fd, STDIN_FILENO);
 943                 dup2(fd, STDOUT_FILENO);
 944                 dup2(fd, STDERR_FILENO);
 945         }
 946         if (fd > STDERR_FILENO)
 947                 close(fd);
 948
 949         /* set scheduling priority for the daemon */
 950         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 951
 952         chdir("/");
 953         umask(022);
 954         setsid();
 955
 956         /* OOM_DISABLE == -17 */
 957         fd = open("/proc/self/oom_adj", O_RDWR);
 958         if (fd < 0) {
 959                 err(udev, "error disabling OOM: %m\n");
 960         } else {
 961                 write(fd, "-17", 3);
 962                 close(fd);
 963         }
 964
 965         /* in trace mode run one event after the other */
 966         if (debug_trace) {
 967                 max_childs = 1;
 968         } else {
 969                 int memsize = mem_size_mb();
 970
 971                 if (memsize > 0)
 972                         max_childs = 128 + (memsize / 8);
 973                 else
 974                         max_childs = 128;
 975         }
 976
 977         /* possibly overwrite maximum limit of executed events */
 978         value = getenv("UDEVD_MAX_CHILDS");
 979         if (value)
 980                 max_childs = strtoul(value, NULL, 10);
 981         info(udev, "initialize max_childs to %u\n", max_childs);
 982
 983         udev_list_init(&event_list);
 984         udev_list_init(&worker_list);
 985
 986         while (!udev_exit) {
 987                 int fdcount;
 988                 int timeout;
 989
 990                 /* set timeout to kill idle workers */
 991                 if (udev_list_is_empty(&event_list) && childs > 2)
 992                         timeout = 3 * 1000;
 993                 else
 994                         timeout = -1;
 995                 /* wait for events */
 996                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
 997                 if (fdcount < 0)
 998                         continue;
 999
1000                 /* timeout - kill idle workers */
1001                 if (fdcount == 0)
1002                         worker_kill(2);
1003
1004                 /* event has finished */
1005                 if (pfd[FD_WORKER].revents & POLLIN)
1006                         worker_returned();
1007
1008                 /* get kernel uevent */
1009                 if (pfd[FD_NETLINK].revents & POLLIN) {
1010                         struct udev_device *dev;
1011
1012                         dev = udev_monitor_receive_device(monitor);
1013                         if (dev != NULL)
1014                                 event_queue_insert(dev);
1015                         else
1016                                 udev_device_unref(dev);
1017                 }
1018
1019                 /* start new events */
1020                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1021                         events_start(udev);
1022
1023                 /* get signal */
1024                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1025                         struct signalfd_siginfo fdsi;
1026                         ssize_t size;
1027
1028                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1029                         if (size == sizeof(struct signalfd_siginfo))
1030                                 handle_signal(udev, fdsi.ssi_signo);
1031                 }
1032
1033                 /* device node and rules directory inotify watch */
1034                 if (pfd[FD_INOTIFY].revents & POLLIN)
1035                         handle_inotify(udev);
1036
1037                 /*
1038                  * get control message
1039                  *
1040                  * This needs to be after the inotify handling, to make sure,
1041                  * that the settle signal is send back after the possibly generated
1042                  * "change" events by the inotify device node watch.
1043                  */
1044                 if (pfd[FD_CONTROL].revents & POLLIN)
1045                         handle_ctrl_msg(udev_ctrl);
1046
1047                 /* rules changed, set by inotify or a HUP signal */
1048                 if (reload_config) {
1049                         struct udev_rules *rules_new;
1050
1051                         worker_kill(0);
1052                         rules_new = udev_rules_new(udev, resolve_names);
1053                         if (rules_new != NULL) {
1054                                 udev_rules_unref(rules);
1055                                 rules = rules_new;
1056                         }
1057                         reload_config = 0;
1058                 }
1059         }
1060
1061         udev_queue_export_cleanup(udev_queue_export);
1062         rc = 0;
1063 exit:
1064         udev_queue_export_unref(udev_queue_export);
1065         udev_rules_unref(rules);
1066         udev_ctrl_unref(udev_ctrl);
1067         if (pfd[FD_SIGNAL].fd >= 0)
1068                 close(pfd[FD_SIGNAL].fd);
1069         if (worker_watch[READ_END] >= 0)
1070                 close(worker_watch[READ_END]);
1071         if (worker_watch[WRITE_END] >= 0)
1072                 close(worker_watch[WRITE_END]);
1073         udev_monitor_unref(monitor);
1074         udev_selinux_exit(udev);
1075         udev_unref(udev);
1076         udev_log_close();
1077         return rc;
1078 }