udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2009 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  * Copyright (C) 2009 Canonical Ltd.
   5  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stdbool.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <fcntl.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <dirent.h>
  34 #include <sys/time.h>
  35 #include <sys/prctl.h>
  36 #include <sys/socket.h>
  37 #include <sys/signalfd.h>
  38 #include <sys/select.h>
  39 #include <sys/poll.h>
  40 #include <sys/wait.h>
  41 #include <sys/stat.h>
  42 #include <sys/ioctl.h>
  43 #include <sys/inotify.h>
  44
  45 #include "udev.h"
  46
  47 #define UDEVD_PRIORITY                  -4
  48 #define UDEV_PRIORITY                   -2
  49
  50 static bool debug;
  51
  52 static void log_fn(struct udev *udev, int priority,
  53                    const char *file, int line, const char *fn,
  54                    const char *format, va_list args)
  55 {
  56         if (debug) {
  57                 char buf[1024];
  58                 struct timeval tv;
  59                 struct timezone tz;
  60
  61                 vsnprintf(buf, sizeof(buf), format, args);
  62                 gettimeofday(&tv, &tz);
  63                 fprintf(stderr, "%llu.%06u [%u] %s: %s",
  64                         (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
  65                         (int) getpid(), fn, buf);
  66         } else {
  67                 vsyslog(priority, format, args);
  68         }
  69 }
  70
  71 static bool debug_trace;
  72 static struct udev_rules *rules;
  73 static struct udev_queue_export *udev_queue_export;
  74 static struct udev_ctrl *udev_ctrl;
  75 static struct udev_monitor *monitor;
  76 static int worker_watch[2];
  77 static pid_t settle_pid;
  78 static bool stop_exec_queue;
  79 static bool reload_config;
  80 static int max_childs;
  81 static int childs;
  82 static sigset_t orig_sigmask;
  83 static struct udev_list_node event_list;
  84 static struct udev_list_node worker_list;
  85 static bool udev_exit;
  86 static volatile sig_atomic_t worker_exit;
  87
  88 enum poll_fd {
  89         FD_CONTROL,
  90         FD_NETLINK,
  91         FD_INOTIFY,
  92         FD_SIGNAL,
  93         FD_WORKER,
  94 };
  95
  96 static struct pollfd pfd[] = {
  97         [FD_NETLINK] = { .events = POLLIN },
  98         [FD_WORKER] =  { .events = POLLIN },
  99         [FD_SIGNAL] =  { .events = POLLIN },
 100         [FD_INOTIFY] = { .events = POLLIN },
 101         [FD_CONTROL] = { .events = POLLIN },
 102 };
 103
 104 enum event_state {
 105         EVENT_UNDEF,
 106         EVENT_QUEUED,
 107         EVENT_RUNNING,
 108 };
 109
 110 struct event {
 111         struct udev_list_node node;
 112         struct udev *udev;
 113         struct udev_device *dev;
 114         enum event_state state;
 115         int exitcode;
 116         unsigned long long int delaying_seqnum;
 117         unsigned long long int seqnum;
 118         const char *devpath;
 119         size_t devpath_len;
 120         const char *devpath_old;
 121 };
 122
 123 static struct event *node_to_event(struct udev_list_node *node)
 124 {
 125         char *event;
 126
 127         event = (char *)node;
 128         event -= offsetof(struct event, node);
 129         return (struct event *)event;
 130 }
 131
 132 enum worker_state {
 133         WORKER_UNDEF,
 134         WORKER_RUNNING,
 135         WORKER_IDLE,
 136         WORKER_KILLED,
 137 };
 138
 139 struct worker {
 140         struct udev_list_node node;
 141         struct udev *udev;
 142         int refcount;
 143         pid_t pid;
 144         struct udev_monitor *monitor;
 145         enum worker_state state;
 146         struct event *event;
 147 };
 148
 149 /* passed from worker to main process */
 150 struct worker_message {
 151         pid_t pid;
 152         int exitcode;
 153 };
 154
 155 static struct worker *node_to_worker(struct udev_list_node *node)
 156 {
 157         char *worker;
 158
 159         worker = (char *)node;
 160         worker -= offsetof(struct worker, node);
 161         return (struct worker *)worker;
 162 }
 163
 164 static void event_queue_delete(struct event *event)
 165 {
 166         udev_list_node_remove(&event->node);
 167
 168         /* mark as failed, if "add" event returns non-zero */
 169         if (event->exitcode != 0 && strcmp(udev_device_get_action(event->dev), "add") == 0)
 170                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 171         else
 172                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 173
 174         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 175         udev_device_unref(event->dev);
 176         free(event);
 177 }
 178
 179 static void event_sig_handler(int signum)
 180 {
 181         switch (signum) {
 182         case SIGALRM:
 183                 _exit(1);
 184                 break;
 185         case SIGTERM:
 186                 worker_exit = true;
 187                 break;
 188         }
 189 }
 190
 191 static struct worker *worker_ref(struct worker *worker)
 192 {
 193         worker->refcount++;
 194         return worker;
 195 }
 196
 197 static void worker_unref(struct worker *worker)
 198 {
 199         worker->refcount--;
 200         if (worker->refcount > 0)
 201                 return;
 202
 203         udev_list_node_remove(&worker->node);
 204         udev_monitor_unref(worker->monitor);
 205         childs--;
 206         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 207         free(worker);
 208 }
 209
 210 static void worker_new(struct event *event)
 211 {
 212         struct worker *worker;
 213         struct udev_monitor *worker_monitor;
 214         pid_t pid;
 215         struct sigaction act;
 216
 217         /* listen for new events */
 218         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 219         if (worker_monitor == NULL)
 220                 return;
 221         /* allow the main daemon netlink address to send devices to the worker */
 222         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 223         udev_monitor_enable_receiving(worker_monitor);
 224         util_set_fd_cloexec(udev_monitor_get_fd(worker_monitor));
 225
 226         worker = calloc(1, sizeof(struct worker));
 227         if (worker == NULL)
 228                 return;
 229         /* worker + event reference */
 230         worker->refcount = 2;
 231         worker->udev = event->udev;
 232
 233         pid = fork();
 234         switch (pid) {
 235         case 0: {
 236                 sigset_t sigmask;
 237                 struct udev_device *dev;
 238                 struct pollfd pmon = {
 239                         .fd = udev_monitor_get_fd(worker_monitor),
 240                         .events = POLLIN,
 241                 };
 242
 243                 udev_queue_export_unref(udev_queue_export);
 244                 udev_monitor_unref(monitor);
 245                 udev_ctrl_unref(udev_ctrl);
 246                 close(pfd[FD_SIGNAL].fd);
 247                 close(worker_watch[READ_END]);
 248                 udev_log_close();
 249                 udev_log_init("udevd-work");
 250                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 251
 252                 /* set signal handlers */
 253                 memset(&act, 0x00, sizeof(act));
 254                 act.sa_handler = event_sig_handler;
 255                 sigemptyset (&act.sa_mask);
 256                 act.sa_flags = 0;
 257                 sigaction(SIGTERM, &act, NULL);
 258                 sigaction(SIGALRM, &act, NULL);
 259
 260                 /* unblock SIGALRM */
 261                 sigfillset(&sigmask);
 262                 sigdelset(&sigmask, SIGALRM);
 263                 sigprocmask(SIG_SETMASK, &sigmask, NULL);
 264                 /* SIGTERM is unblocked in ppoll() */
 265                 sigdelset(&sigmask, SIGTERM);
 266
 267                 /* request TERM signal if parent exits */
 268                 prctl(PR_SET_PDEATHSIG, SIGTERM);
 269
 270                 /* initial device */
 271                 dev = event->dev;
 272
 273                 do {
 274                         struct udev_event *udev_event;
 275                         struct worker_message msg = {};
 276                         int err;
 277                         int failed = 0;
 278
 279                         info(event->udev, "seq %llu running\n", udev_device_get_seqnum(dev));
 280                         udev_event = udev_event_new(dev);
 281                         if (udev_event == NULL)
 282                                 _exit(3);
 283
 284                         /* set timeout to prevent hanging processes */
 285                         alarm(UDEV_EVENT_TIMEOUT);
 286
 287                         /* apply rules, create node, symlinks */
 288                         err = udev_event_execute_rules(udev_event, rules);
 289
 290                         /* rules may change/disable the timeout */
 291                         if (udev_device_get_event_timeout(dev) >= 0)
 292                                 alarm(udev_device_get_event_timeout(dev));
 293
 294                         /* execute RUN= */
 295                         if (err == 0 && !udev_event->ignore_device && udev_get_run(udev_event->udev))
 296                                 failed = udev_event_execute_run(udev_event,
 297                                                                 &orig_sigmask);
 298
 299                         /* reset alarm */
 300                         alarm(0);
 301
 302                         /* apply/restore inotify watch */
 303                         if (err == 0 && udev_event->inotify_watch) {
 304                                 udev_watch_begin(udev_event->udev, dev);
 305                                 udev_device_update_db(dev);
 306                         }
 307
 308                         /* send processed event back to libudev listeners */
 309                         udev_monitor_send_device(worker_monitor, NULL, dev);
 310
 311                         /* send back the result of the event execution */
 312                         if (err != 0)
 313                                 msg.exitcode = err;
 314                         else if (failed != 0)
 315                                 msg.exitcode = failed;
 316                         msg.pid = getpid();
 317                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 318
 319                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 320                         udev_event_unref(udev_event);
 321                         udev_device_unref(dev);
 322                         dev = NULL;
 323
 324                         /* wait for more device messages or signal from udevd */
 325                         while (!worker_exit) {
 326                                 int fdcount;
 327
 328                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 329                                 if (fdcount < 0)
 330                                         continue;
 331
 332                                 if (pmon.revents & POLLIN) {
 333                                         dev = udev_monitor_receive_device(worker_monitor);
 334                                         if (dev != NULL)
 335                                                 break;
 336                                 }
 337                         }
 338                 } while (dev != NULL);
 339
 340                 udev_monitor_unref(worker_monitor);
 341                 udev_log_close();
 342                 exit(0);
 343         }
 344         case -1:
 345                 udev_monitor_unref(worker_monitor);
 346                 event->state = EVENT_QUEUED;
 347                 free(worker);
 348                 err(event->udev, "fork of child failed: %m\n");
 349                 break;
 350         default:
 351                 /* close monitor, but keep address around */
 352                 udev_monitor_disconnect(worker_monitor);
 353                 worker->monitor = worker_monitor;
 354                 worker->pid = pid;
 355                 worker->state = WORKER_RUNNING;
 356                 worker->event = event;
 357                 event->state = EVENT_RUNNING;
 358                 udev_list_node_append(&worker->node, &worker_list);
 359                 childs++;
 360                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 361                 break;
 362         }
 363 }
 364
 365 static void event_run(struct event *event)
 366 {
 367         struct udev_list_node *loop;
 368
 369         udev_list_node_foreach(loop, &worker_list) {
 370                 struct worker *worker = node_to_worker(loop);
 371                 ssize_t count;
 372
 373                 if (worker->state != WORKER_IDLE)
 374                         continue;
 375
 376                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 377                 if (count < 0) {
 378                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 379                         kill(worker->pid, SIGKILL);
 380                         worker->state = WORKER_KILLED;
 381                         continue;
 382                 }
 383                 worker_ref(worker);
 384                 worker->event = event;
 385                 worker->state = WORKER_RUNNING;
 386                 event->state = EVENT_RUNNING;
 387                 return;
 388         }
 389
 390         if (childs >= max_childs) {
 391                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 392                 return;
 393         }
 394
 395         /* start new worker and pass initial device */
 396         worker_new(event);
 397 }
 398
 399 static void event_queue_insert(struct udev_device *dev)
 400 {
 401         struct event *event;
 402
 403         event = calloc(1, sizeof(struct event));
 404         if (event == NULL)
 405                 return;
 406
 407         event->udev = udev_device_get_udev(dev);
 408         event->dev = dev;
 409         event->seqnum = udev_device_get_seqnum(dev);
 410         event->devpath = udev_device_get_devpath(dev);
 411         event->devpath_len = strlen(event->devpath);
 412         event->devpath_old = udev_device_get_devpath_old(dev);
 413
 414         udev_queue_export_device_queued(udev_queue_export, dev);
 415         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 416              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 417
 418         event->state = EVENT_QUEUED;
 419         udev_list_node_append(&event->node, &event_list);
 420
 421         /* run all events with a timeout set immediately */
 422         if (udev_device_get_timeout(dev) > 0) {
 423                 worker_new(event);
 424                 return;
 425         }
 426 }
 427
 428 static void worker_kill(struct udev *udev, int retain)
 429 {
 430         struct udev_list_node *loop;
 431         int max;
 432
 433         if (childs <= retain)
 434                 return;
 435
 436         max = childs - retain;
 437
 438         udev_list_node_foreach(loop, &worker_list) {
 439                 struct worker *worker = node_to_worker(loop);
 440
 441                 if (max-- <= 0)
 442                         break;
 443
 444                 if (worker->state == WORKER_KILLED)
 445                         continue;
 446
 447                 worker->state = WORKER_KILLED;
 448                 kill(worker->pid, SIGTERM);
 449         }
 450 }
 451
 452 static int mem_size_mb(void)
 453 {
 454         FILE *f;
 455         char buf[4096];
 456         long int memsize = -1;
 457
 458         f = fopen("/proc/meminfo", "r");
 459         if (f == NULL)
 460                 return -1;
 461
 462         while (fgets(buf, sizeof(buf), f) != NULL) {
 463                 long int value;
 464
 465                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 466                         memsize = value / 1024;
 467                         break;
 468                 }
 469         }
 470
 471         fclose(f);
 472         return memsize;
 473 }
 474
 475 /* lookup event for identical, parent, child device */
 476 static int devpath_busy(struct event *event)
 477 {
 478         struct udev_list_node *loop;
 479         size_t common;
 480
 481         /* check if queue contains events we depend on */
 482         udev_list_node_foreach(loop, &event_list) {
 483                 struct event *loop_event = node_to_event(loop);
 484
 485                 /* we already found a later event, earlier can not block us, no need to check again */
 486                 if (loop_event->seqnum < event->delaying_seqnum)
 487                         continue;
 488
 489                 /* event we checked earlier still exists, no need to check again */
 490                 if (loop_event->seqnum == event->delaying_seqnum)
 491                         return 2;
 492
 493                 /* found ourself, no later event can block us */
 494                 if (loop_event->seqnum >= event->seqnum)
 495                         break;
 496
 497                 /* check our old name */
 498                 if (event->devpath_old != NULL)
 499                         if (strcmp(loop_event->devpath, event->devpath_old) == 0) {
 500                                 event->delaying_seqnum = loop_event->seqnum;
 501                                 return 3;
 502                         }
 503
 504                 /* compare devpath */
 505                 common = MIN(loop_event->devpath_len, event->devpath_len);
 506
 507                 /* one devpath is contained in the other? */
 508                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 509                         continue;
 510
 511                 /* identical device event found */
 512                 if (loop_event->devpath_len == event->devpath_len) {
 513                         event->delaying_seqnum = loop_event->seqnum;
 514                         return 4;
 515                 }
 516
 517                 /* parent device event found */
 518                 if (event->devpath[common] == '/') {
 519                         event->delaying_seqnum = loop_event->seqnum;
 520                         return 5;
 521                 }
 522
 523                 /* child device event found */
 524                 if (loop_event->devpath[common] == '/') {
 525                         event->delaying_seqnum = loop_event->seqnum;
 526                         return 6;
 527                 }
 528
 529                 /* no matching device */
 530                 continue;
 531         }
 532
 533         return 0;
 534 }
 535
 536 static void events_start(struct udev *udev)
 537 {
 538         struct udev_list_node *loop;
 539
 540         udev_list_node_foreach(loop, &event_list) {
 541                 struct event *event = node_to_event(loop);
 542
 543                 if (event->state != EVENT_QUEUED)
 544                         continue;
 545
 546                 /* do not start event if parent or child event is still running */
 547                 if (devpath_busy(event) != 0) {
 548                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 549                         continue;
 550                 }
 551
 552                 event_run(event);
 553         }
 554 }
 555
 556 static void worker_returned(void)
 557 {
 558         while (1) {
 559                 struct worker_message msg;
 560                 ssize_t size;
 561                 struct udev_list_node *loop;
 562
 563                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 564                 if (size != sizeof(struct worker_message))
 565                         break;
 566
 567                 /* lookup worker who sent the signal */
 568                 udev_list_node_foreach(loop, &worker_list) {
 569                         struct worker *worker = node_to_worker(loop);
 570
 571                         if (worker->pid != msg.pid)
 572                                 continue;
 573
 574                         /* worker returned */
 575                         worker->event->exitcode = msg.exitcode;
 576                         event_queue_delete(worker->event);
 577                         worker->event = NULL;
 578                         if (worker->state != WORKER_KILLED)
 579                                 worker->state = WORKER_IDLE;
 580                         worker_unref(worker);
 581                         break;
 582                 }
 583         }
 584 }
 585
 586 /* receive the udevd message from userspace */
 587 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 588 {
 589         struct udev *udev = udev_ctrl_get_udev(uctrl);
 590         struct udev_ctrl_msg *ctrl_msg;
 591         const char *str;
 592         int i;
 593
 594         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 595         if (ctrl_msg == NULL)
 596                 return;
 597
 598         i = udev_ctrl_get_set_log_level(ctrl_msg);
 599         if (i >= 0) {
 600                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 601                 udev_set_log_priority(udev, i);
 602                 worker_kill(udev, 0);
 603         }
 604
 605         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 606                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 607                 stop_exec_queue = true;
 608         }
 609
 610         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 611                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 612                 stop_exec_queue = false;
 613         }
 614
 615         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 616                 info(udev, "udevd message (RELOAD_RULES) received\n");
 617                 reload_config = true;
 618         }
 619
 620         str = udev_ctrl_get_set_env(ctrl_msg);
 621         if (str != NULL) {
 622                 char *key;
 623
 624                 key = strdup(str);
 625                 if (key != NULL) {
 626                         char *val;
 627
 628                         val = strchr(key, '=');
 629                         if (val != NULL) {
 630                                 val[0] = '\0';
 631                                 val = &val[1];
 632                                 if (val[0] == '\0') {
 633                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 634                                         udev_add_property(udev, key, NULL);
 635                                 } else {
 636                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 637                                         udev_add_property(udev, key, val);
 638                                 }
 639                         } else {
 640                                 err(udev, "wrong key format '%s'\n", key);
 641                         }
 642                         free(key);
 643                 }
 644                 worker_kill(udev, 0);
 645         }
 646
 647         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 648         if (i >= 0) {
 649                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 650                 max_childs = i;
 651         }
 652
 653         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 654         if (settle_pid > 0) {
 655                 info(udev, "udevd message (SETTLE) received\n");
 656                 kill(settle_pid, SIGUSR1);
 657                 settle_pid = 0;
 658         }
 659         udev_ctrl_msg_unref(ctrl_msg);
 660 }
 661
 662 /* read inotify messages */
 663 static int handle_inotify(struct udev *udev)
 664 {
 665         ssize_t nbytes, pos;
 666         char *buf;
 667         struct inotify_event *ev;
 668
 669         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 670                 return 0;
 671
 672         buf = malloc(nbytes);
 673         if (buf == NULL) {
 674                 err(udev, "error getting buffer for inotify\n");
 675                 return -1;
 676         }
 677
 678         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 679
 680         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 681                 struct udev_device *dev;
 682
 683                 ev = (struct inotify_event *)(buf + pos);
 684                 if (ev->len) {
 685                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 686                         reload_config = true;
 687                         continue;
 688                 }
 689
 690                 dev = udev_watch_lookup(udev, ev->wd);
 691                 if (dev != NULL) {
 692                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 693                         if (ev->mask & IN_CLOSE_WRITE) {
 694                                 char filename[UTIL_PATH_SIZE];
 695                                 int fd;
 696
 697                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 698                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 699                                 fd = open(filename, O_WRONLY);
 700                                 if (fd < 0 || write(fd, "change", 6) < 0)
 701                                         info(udev, "error writing uevent: %m\n");
 702                                 close(fd);
 703                         }
 704                         if (ev->mask & IN_IGNORED)
 705                                 udev_watch_end(udev, dev);
 706
 707                         udev_device_unref(dev);
 708                 }
 709
 710         }
 711
 712         free(buf);
 713         return 0;
 714 }
 715
 716 static void handle_signal(struct udev *udev, int signo)
 717 {
 718         switch (signo) {
 719         case SIGINT:
 720         case SIGTERM:
 721                 udev_exit = true;
 722                 break;
 723         case SIGCHLD:
 724                 while (1) {
 725                         pid_t pid;
 726                         int status;
 727                         struct udev_list_node *loop, *tmp;
 728
 729                         pid = waitpid(-1, &status, WNOHANG);
 730                         if (pid <= 0)
 731                                 break;
 732
 733                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 734                                 struct worker *worker = node_to_worker(loop);
 735
 736                                 if (worker->pid != pid)
 737                                         continue;
 738
 739                                 info(udev, "worker [%u] exit\n", pid);
 740                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 741                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 742                                         if (worker->event != NULL) {
 743                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 744                                                 worker->event->exitcode = -32;
 745                                                 event_queue_delete(worker->event);
 746                                                 /* drop reference from running event */
 747                                                 worker_unref(worker);
 748                                         }
 749                                 }
 750                                 worker_unref(worker);
 751                                 break;
 752                         }
 753                 }
 754                 break;
 755         case SIGHUP:
 756                 reload_config = true;
 757                 break;
 758         }
 759 }
 760
 761 static void startup_log(struct udev *udev)
 762 {
 763         FILE *f;
 764         char path[UTIL_PATH_SIZE];
 765         struct stat statbuf;
 766
 767         f = fopen("/dev/kmsg", "w");
 768         if (f != NULL)
 769                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 770
 771         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 772         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 773                 const char *depr_str =
 774                         "udev: missing sysfs features; please update the kernel "
 775                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 776                         "udev may fail to work correctly";
 777
 778                 if (f != NULL)
 779                         fprintf(f, "<3>%s\n", depr_str);
 780                 err(udev, "%s\n", depr_str);
 781                 sleep(15);
 782         }
 783
 784         if (f != NULL)
 785                 fclose(f);
 786 }
 787
 788 int main(int argc, char *argv[])
 789 {
 790         struct udev *udev;
 791         int fd;
 792         sigset_t mask;
 793         const char *value;
 794         int daemonize = false;
 795         int resolve_names = 1;
 796         static const struct option options[] = {
 797                 { "daemon", no_argument, NULL, 'd' },
 798                 { "debug-trace", no_argument, NULL, 't' },
 799                 { "debug", no_argument, NULL, 'D' },
 800                 { "help", no_argument, NULL, 'h' },
 801                 { "version", no_argument, NULL, 'V' },
 802                 { "resolve-names", required_argument, NULL, 'N' },
 803                 {}
 804         };
 805         int rc = 1;
 806
 807         udev = udev_new();
 808         if (udev == NULL)
 809                 goto exit;
 810
 811         udev_log_init("udevd");
 812         udev_set_log_fn(udev, log_fn);
 813         info(udev, "version %s\n", VERSION);
 814         udev_selinux_init(udev);
 815
 816         while (1) {
 817                 int option;
 818
 819                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 820                 if (option == -1)
 821                         break;
 822
 823                 switch (option) {
 824                 case 'd':
 825                         daemonize = true;
 826                         break;
 827                 case 't':
 828                         debug_trace = true;
 829                         break;
 830                 case 'D':
 831                         debug = true;
 832                         if (udev_get_log_priority(udev) < LOG_INFO)
 833                                 udev_set_log_priority(udev, LOG_INFO);
 834                         break;
 835                 case 'N':
 836                         if (strcmp (optarg, "early") == 0) {
 837                                 resolve_names = 1;
 838                         } else if (strcmp (optarg, "late") == 0) {
 839                                 resolve_names = 0;
 840                         } else if (strcmp (optarg, "never") == 0) {
 841                                 resolve_names = -1;
 842                         } else {
 843                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 844                                 err(udev, "resolve-names must be early, late or never\n");
 845                                 goto exit;
 846                         }
 847                         break;
 848                 case 'h':
 849                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 850                                "[--resolve-names=early|late|never] [--version]\n");
 851                         goto exit;
 852                 case 'V':
 853                         printf("%s\n", VERSION);
 854                         goto exit;
 855                 default:
 856                         goto exit;
 857                 }
 858         }
 859
 860         if (getuid() != 0) {
 861                 fprintf(stderr, "root privileges required\n");
 862                 err(udev, "root privileges required\n");
 863                 goto exit;
 864         }
 865
 866         /* make sure std{in,out,err} fd's are in a sane state */
 867         fd = open("/dev/null", O_RDWR);
 868         if (fd < 0) {
 869                 fprintf(stderr, "cannot open /dev/null\n");
 870                 err(udev, "cannot open /dev/null\n");
 871         }
 872         if (write(STDOUT_FILENO, 0, 0) < 0)
 873                 dup2(fd, STDOUT_FILENO);
 874         if (write(STDERR_FILENO, 0, 0) < 0)
 875                 dup2(fd, STDERR_FILENO);
 876
 877         /* init control socket, bind() ensures, that only one udevd instance is running */
 878         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 879         if (udev_ctrl == NULL) {
 880                 fprintf(stderr, "error initializing control socket");
 881                 err(udev, "error initializing udevd socket");
 882                 rc = 1;
 883                 goto exit;
 884         }
 885         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 886                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 887                 err(udev, "error binding control socket, seems udevd is already running\n");
 888                 rc = 1;
 889                 goto exit;
 890         }
 891         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 892
 893         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 894         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 895                 fprintf(stderr, "error initializing netlink socket\n");
 896                 err(udev, "error initializing netlink socket\n");
 897                 rc = 3;
 898                 goto exit;
 899         }
 900         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 901         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 902
 903         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 904         if (pfd[FD_INOTIFY].fd < 0) {
 905                 fprintf(stderr, "error initializing inotify\n");
 906                 err(udev, "error initializing inotify\n");
 907                 rc = 4;
 908                 goto exit;
 909         }
 910
 911         if (udev_get_rules_path(udev) != NULL) {
 912                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 913                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 914         } else {
 915                 char filename[UTIL_PATH_SIZE];
 916
 917                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 918                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 919                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 920                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 921
 922                 /* watch dynamic rules directory */
 923                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 924                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 925                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 926         }
 927         udev_watch_restore(udev);
 928
 929         /* block and listen to all signals on signalfd */
 930         sigfillset(&mask);
 931         sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
 932         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 933         if (pfd[FD_SIGNAL].fd < 0) {
 934                 fprintf(stderr, "error getting signalfd\n");
 935                 err(udev, "error getting signalfd\n");
 936                 rc = 5;
 937                 goto exit;
 938         }
 939
 940         /* unnamed socket from workers to the main daemon */
 941         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 942                 fprintf(stderr, "error getting socketpair\n");
 943                 err(udev, "error getting socketpair\n");
 944                 rc = 6;
 945                 goto exit;
 946         }
 947         pfd[FD_WORKER].fd = worker_watch[READ_END];
 948         util_set_fd_cloexec(worker_watch[WRITE_END]);
 949
 950         rules = udev_rules_new(udev, resolve_names);
 951         if (rules == NULL) {
 952                 err(udev, "error reading rules\n");
 953                 goto exit;
 954         }
 955
 956         udev_queue_export = udev_queue_export_new(udev);
 957         if (udev_queue_export == NULL) {
 958                 err(udev, "error creating queue file\n");
 959                 goto exit;
 960         }
 961
 962         if (daemonize) {
 963                 pid_t pid;
 964
 965                 pid = fork();
 966                 switch (pid) {
 967                 case 0:
 968                         break;
 969                 case -1:
 970                         err(udev, "fork of daemon failed: %m\n");
 971                         rc = 4;
 972                         goto exit;
 973                 default:
 974                         rc = 0;
 975                         goto exit;
 976                 }
 977         }
 978
 979         startup_log(udev);
 980
 981         /* redirect std{out,err} */
 982         if (!debug && !debug_trace) {
 983                 dup2(fd, STDIN_FILENO);
 984                 dup2(fd, STDOUT_FILENO);
 985                 dup2(fd, STDERR_FILENO);
 986         }
 987         if (fd > STDERR_FILENO)
 988                 close(fd);
 989
 990         /* set scheduling priority for the daemon */
 991         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 992
 993         chdir("/");
 994         umask(022);
 995         setsid();
 996
 997         /* OOM_DISABLE == -17 */
 998         fd = open("/proc/self/oom_adj", O_RDWR);
 999         if (fd < 0) {
1000                 err(udev, "error disabling OOM: %m\n");
1001         } else {
1002                 write(fd, "-17", 3);
1003                 close(fd);
1004         }
1005
1006         /* in trace mode run one event after the other */
1007         if (debug_trace) {
1008                 max_childs = 1;
1009         } else {
1010                 int memsize = mem_size_mb();
1011
1012                 if (memsize > 0)
1013                         max_childs = 128 + (memsize / 8);
1014                 else
1015                         max_childs = 128;
1016         }
1017
1018         /* possibly overwrite maximum limit of executed events */
1019         value = getenv("UDEVD_MAX_CHILDS");
1020         if (value)
1021                 max_childs = strtoul(value, NULL, 10);
1022         info(udev, "initialize max_childs to %u\n", max_childs);
1023
1024         udev_list_init(&event_list);
1025         udev_list_init(&worker_list);
1026
1027         while (!udev_exit) {
1028                 int fdcount;
1029                 int timeout;
1030
1031                 /* set timeout to kill idle workers */
1032                 if (udev_list_is_empty(&event_list) && childs > 2)
1033                         timeout = 3 * 1000;
1034                 else
1035                         timeout = -1;
1036                 /* wait for events */
1037                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1038                 if (fdcount < 0)
1039                         continue;
1040
1041                 /* timeout - kill idle workers */
1042                 if (fdcount == 0)
1043                         worker_kill(udev, 2);
1044
1045                 /* event has finished */
1046                 if (pfd[FD_WORKER].revents & POLLIN)
1047                         worker_returned();
1048
1049                 /* get kernel uevent */
1050                 if (pfd[FD_NETLINK].revents & POLLIN) {
1051                         struct udev_device *dev;
1052
1053                         dev = udev_monitor_receive_device(monitor);
1054                         if (dev != NULL)
1055                                 event_queue_insert(dev);
1056                         else
1057                                 udev_device_unref(dev);
1058                 }
1059
1060                 /* start new events */
1061                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1062                         events_start(udev);
1063
1064                 /* get signal */
1065                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1066                         struct signalfd_siginfo fdsi;
1067                         ssize_t size;
1068
1069                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1070                         if (size == sizeof(struct signalfd_siginfo))
1071                                 handle_signal(udev, fdsi.ssi_signo);
1072                 }
1073
1074                 /* device node and rules directory inotify watch */
1075                 if (pfd[FD_INOTIFY].revents & POLLIN)
1076                         handle_inotify(udev);
1077
1078                 /*
1079                  * get control message
1080                  *
1081                  * This needs to be after the inotify handling, to make sure,
1082                  * that the settle signal is send back after the possibly generated
1083                  * "change" events by the inotify device node watch.
1084                  */
1085                 if (pfd[FD_CONTROL].revents & POLLIN)
1086                         handle_ctrl_msg(udev_ctrl);
1087
1088                 /* rules changed, set by inotify or a HUP signal */
1089                 if (reload_config) {
1090                         struct udev_rules *rules_new;
1091
1092                         worker_kill(udev, 0);
1093                         rules_new = udev_rules_new(udev, resolve_names);
1094                         if (rules_new != NULL) {
1095                                 udev_rules_unref(rules);
1096                                 rules = rules_new;
1097                         }
1098                         reload_config = 0;
1099                 }
1100         }
1101
1102         udev_queue_export_cleanup(udev_queue_export);
1103         rc = 0;
1104 exit:
1105         udev_queue_export_unref(udev_queue_export);
1106         udev_rules_unref(rules);
1107         udev_ctrl_unref(udev_ctrl);
1108         if (pfd[FD_SIGNAL].fd >= 0)
1109                 close(pfd[FD_SIGNAL].fd);
1110         if (worker_watch[READ_END] >= 0)
1111                 close(worker_watch[READ_END]);
1112         if (worker_watch[WRITE_END] >= 0)
1113                 close(worker_watch[WRITE_END]);
1114         udev_monitor_unref(monitor);
1115         udev_selinux_exit(udev);
1116         udev_unref(udev);
1117         udev_log_close();
1118         return rc;
1119 }