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