udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2008 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/select.h>
  34 #include <sys/poll.h>
  35 #include <sys/wait.h>
  36 #include <sys/stat.h>
  37 #include <sys/ioctl.h>
  38 #ifdef HAVE_INOTIFY
  39 #include <sys/inotify.h>
  40 #endif
  41
  42 #include "udev.h"
  43
  44 #define UDEVD_PRIORITY                  -4
  45 #define UDEV_PRIORITY                   -2
  46
  47 /* maximum limit of forked childs */
  48 #define UDEVD_MAX_CHILDS                256
  49
  50 static int 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                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  58                 vfprintf(stderr, format, args);
  59         } else {
  60                 vsyslog(priority, format, args);
  61         }
  62 }
  63
  64 static void reap_sigchilds(void);
  65
  66 static int debug_trace;
  67 static struct udev_rules *rules;
  68 static struct udev_queue_export *udev_queue_export;
  69 static struct udev_ctrl *udev_ctrl;
  70 static struct udev_monitor *kernel_monitor;
  71 static volatile sig_atomic_t sigchilds_waiting;
  72 static volatile sig_atomic_t udev_exit;
  73 static volatile sig_atomic_t reload_config;
  74 static volatile sig_atomic_t signal_received;
  75 static volatile pid_t settle_pid;
  76 static int run_exec_q;
  77 static int stop_exec_q;
  78 static int max_childs;
  79 static int childs;
  80 static struct udev_list_node event_list;
  81
  82 static struct udev_event *node_to_event(struct udev_list_node *node)
  83 {
  84         char *event;
  85
  86         event = (char *)node;
  87         event -= offsetof(struct udev_event, node);
  88         return (struct udev_event *)event;
  89 }
  90
  91 static void event_queue_delete(struct udev_event *event)
  92 {
  93         udev_list_node_remove(&event->node);
  94
  95         /* mark as failed, if "add" event returns non-zero */
  96         if (event->exitstatus && strcmp(udev_device_get_action(event->dev), "add") == 0)
  97                 udev_queue_export_device_failed(udev_queue_export, event->dev);
  98         else
  99                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 100
 101         udev_device_unref(event->dev);
 102         udev_event_unref(event);
 103 }
 104
 105 static void event_sig_handler(int signum)
 106 {
 107         if (signum == SIGALRM)
 108                 _exit(1);
 109 }
 110
 111 static void event_fork(struct udev_event *event)
 112 {
 113         pid_t pid;
 114         struct sigaction act;
 115         int err;
 116
 117 #if 0
 118         /* single process, no forking, just for testing/profiling */
 119         err = udev_event_execute_rules(event, rules);
 120         if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 121                 udev_event_execute_run(event);
 122         info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 123         event_queue_delete(event);
 124         return;
 125 #endif
 126
 127         if (debug_trace) {
 128                 event->trace = 1;
 129                 fprintf(stderr, "fork %s (%llu)\n",
 130                        udev_device_get_syspath(event->dev),
 131                        udev_device_get_seqnum(event->dev));
 132         }
 133
 134         pid = fork();
 135         switch (pid) {
 136         case 0:
 137                 /* child */
 138                 udev_queue_export_unref(udev_queue_export);
 139                 udev_ctrl_unref(udev_ctrl);
 140                 logging_close();
 141                 logging_init("udevd-event");
 142                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 143
 144                 /* set signal handlers */
 145                 memset(&act, 0x00, sizeof(act));
 146                 act.sa_handler = event_sig_handler;
 147                 sigemptyset (&act.sa_mask);
 148                 act.sa_flags = 0;
 149                 sigaction(SIGALRM, &act, NULL);
 150
 151                 /* reset to default */
 152                 act.sa_handler = SIG_DFL;
 153                 sigaction(SIGINT, &act, NULL);
 154                 sigaction(SIGTERM, &act, NULL);
 155                 sigaction(SIGCHLD, &act, NULL);
 156                 sigaction(SIGHUP, &act, NULL);
 157
 158                 /* set timeout to prevent hanging processes */
 159                 alarm(UDEV_EVENT_TIMEOUT);
 160
 161                 /* apply rules, create node, symlinks */
 162                 err = udev_event_execute_rules(event, rules);
 163
 164                 /* rules may change/disable the timeout */
 165                 if (udev_device_get_event_timeout(event->dev) >= 0)
 166                         alarm(udev_device_get_event_timeout(event->dev));
 167
 168                 /* execute RUN= */
 169                 if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 170                         udev_event_execute_run(event);
 171
 172                 /* apply/restore inotify watch */
 173                 if (err == 0 && event->inotify_watch) {
 174                         udev_watch_begin(event->udev, event->dev);
 175                         udev_device_update_db(event->dev);
 176                 }
 177
 178                 /* send processed event back to the kernel netlink socket */
 179                 udev_monitor_send_device(kernel_monitor, event->dev);
 180
 181                 info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 182                 logging_close();
 183                 if (err != 0)
 184                         exit(1);
 185                 exit(0);
 186         case -1:
 187                 err(event->udev, "fork of child failed: %m\n");
 188                 event_queue_delete(event);
 189                 break;
 190         default:
 191                 /* get SIGCHLD in main loop */
 192                 info(event->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 193                      udev_device_get_seqnum(event->dev),
 194                      pid,
 195                      udev_device_get_action(event->dev),
 196                      udev_device_get_subsystem(event->dev),
 197                      time(NULL) - event->queue_time);
 198                 event->pid = pid;
 199                 childs++;
 200         }
 201 }
 202
 203 static void event_queue_insert(struct udev_event *event)
 204 {
 205         event->queue_time = time(NULL);
 206
 207         udev_queue_export_device_queued(udev_queue_export, event->dev);
 208         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(event->dev),
 209              udev_device_get_action(event->dev), udev_device_get_subsystem(event->dev));
 210
 211         udev_list_node_append(&event->node, &event_list);
 212         run_exec_q = 1;
 213
 214         /* run all events with a timeout set immediately */
 215         if (udev_device_get_timeout(event->dev) > 0) {
 216                 event_fork(event);
 217                 return;
 218         }
 219 }
 220
 221 static int mem_size_mb(void)
 222 {
 223         FILE *f;
 224         char buf[4096];
 225         long int memsize = -1;
 226
 227         f = fopen("/proc/meminfo", "r");
 228         if (f == NULL)
 229                 return -1;
 230
 231         while (fgets(buf, sizeof(buf), f) != NULL) {
 232                 long int value;
 233
 234                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 235                         memsize = value / 1024;
 236                         break;
 237                 }
 238         }
 239
 240         fclose(f);
 241         return memsize;
 242 }
 243
 244 static int compare_devpath(const char *running, const char *waiting)
 245 {
 246         int i = 0;
 247
 248         while (running[i] != '\0' && running[i] == waiting[i])
 249                 i++;
 250
 251         /* identical device event found */
 252         if (running[i] == '\0' && waiting[i] == '\0')
 253                 return 1;
 254
 255         /* parent device event found */
 256         if (running[i] == '\0' && waiting[i] == '/')
 257                 return 2;
 258
 259         /* child device event found */
 260         if (running[i] == '/' && waiting[i] == '\0')
 261                 return 3;
 262
 263         /* no matching event */
 264         return 0;
 265 }
 266
 267 /* lookup event for identical, parent, child device */
 268 static int devpath_busy(struct udev_event *event)
 269 {
 270         struct udev_list_node *loop;
 271
 272         /* check if queue contains events we depend on */
 273         udev_list_node_foreach(loop, &event_list) {
 274                 struct udev_event *loop_event = node_to_event(loop);
 275
 276                 /* we already found a later event, earlier can not block us, no need to check again */
 277                 if (udev_device_get_seqnum(loop_event->dev) < event->delaying_seqnum)
 278                         continue;
 279
 280                 /* event we checked earlier still exists, no need to check again */
 281                 if (udev_device_get_seqnum(loop_event->dev) == event->delaying_seqnum)
 282                         return 2;
 283
 284                 /* found ourself, no later event can block us */
 285                 if (udev_device_get_seqnum(loop_event->dev) >= udev_device_get_seqnum(event->dev))
 286                         break;
 287
 288                 /* check our old name */
 289                 if (udev_device_get_devpath_old(event->dev) != NULL)
 290                         if (strcmp(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath_old(event->dev)) == 0) {
 291                                 event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 292                                 return 3;
 293                         }
 294
 295                 /* check identical, parent, or child device event */
 296                 if (compare_devpath(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath(event->dev)) != 0) {
 297                         dbg(event->udev, "%llu, device event still pending %llu (%s)\n",
 298                             udev_device_get_seqnum(event->dev),
 299                             udev_device_get_seqnum(loop_event->dev),
 300                             udev_device_get_devpath(loop_event->dev));
 301                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 302                         return 4;
 303                 }
 304
 305                 /* check for our major:minor number */
 306                 if (major(udev_device_get_devnum(event->dev)) > 0 &&
 307                     udev_device_get_devnum(loop_event->dev) == udev_device_get_devnum(event->dev) &&
 308                     strcmp(udev_device_get_subsystem(event->dev), udev_device_get_subsystem(loop_event->dev)) == 0) {
 309                         dbg(event->udev, "%llu, device event still pending %llu (%d:%d)\n",
 310                             udev_device_get_seqnum(event->dev),
 311                             udev_device_get_seqnum(loop_event->dev),
 312                             major(udev_device_get_devnum(loop_event->dev)), minor(udev_device_get_devnum(loop_event->dev)));
 313                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 314                         return 5;
 315                 }
 316         }
 317         return 0;
 318 }
 319
 320 /* serializes events for the identical and parent and child devices */
 321 static void event_queue_manager(struct udev *udev)
 322 {
 323         struct udev_list_node *loop;
 324         struct udev_list_node *tmp;
 325
 326 start_over:
 327         if (udev_list_is_empty(&event_list)) {
 328                 if (childs > 0) {
 329                         err(udev, "event list empty, but childs count is %i", childs);
 330                         childs = 0;
 331                 }
 332                 return;
 333         }
 334
 335         udev_list_node_foreach_safe(loop, tmp, &event_list) {
 336                 struct udev_event *loop_event = node_to_event(loop);
 337
 338                 if (childs >= max_childs) {
 339                         info(udev, "maximum number (%i) of childs reached\n", childs);
 340                         break;
 341                 }
 342
 343                 if (loop_event->pid != 0)
 344                         continue;
 345
 346                 /* do not start event if parent or child event is still running */
 347                 if (devpath_busy(loop_event) != 0) {
 348                         dbg(udev, "delay seq %llu (%s)\n",
 349                             udev_device_get_seqnum(loop_event->dev),
 350                             udev_device_get_devpath(loop_event->dev));
 351                         continue;
 352                 }
 353
 354                 event_fork(loop_event);
 355                 dbg(udev, "moved seq %llu to running list\n", udev_device_get_seqnum(loop_event->dev));
 356
 357                 /* retry if events finished in the meantime */
 358                 if (sigchilds_waiting) {
 359                         sigchilds_waiting = 0;
 360                         reap_sigchilds();
 361                         goto start_over;
 362                 }
 363         }
 364 }
 365
 366 /* receive the udevd message from userspace */
 367 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 368 {
 369         struct udev *udev = udev_ctrl_get_udev(uctrl);
 370         struct udev_ctrl_msg *ctrl_msg;
 371         const char *str;
 372         int i;
 373
 374         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 375         if (ctrl_msg == NULL)
 376                 return;
 377
 378         i = udev_ctrl_get_set_log_level(ctrl_msg);
 379         if (i >= 0) {
 380                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 381                 udev_set_log_priority(udev, i);
 382         }
 383
 384         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 385                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 386                 stop_exec_q = 1;
 387         }
 388
 389         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 390                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 391                 stop_exec_q = 0;
 392                 event_queue_manager(udev);
 393         }
 394
 395         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 396                 info(udev, "udevd message (RELOAD_RULES) received\n");
 397                 reload_config = 1;
 398         }
 399
 400         str = udev_ctrl_get_set_env(ctrl_msg);
 401         if (str != NULL) {
 402                 char *key;
 403
 404                 key = strdup(str);
 405                 if (key != NULL) {
 406                         char *val;
 407
 408                         val = strchr(key, '=');
 409                         if (val != NULL) {
 410                                 val[0] = '\0';
 411                                 val = &val[1];
 412                                 if (val[0] == '\0') {
 413                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 414                                         udev_add_property(udev, key, NULL);
 415                                 } else {
 416                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 417                                         udev_add_property(udev, key, val);
 418                                 }
 419                         } else {
 420                                 err(udev, "wrong key format '%s'\n", key);
 421                         }
 422                         free(key);
 423                 }
 424         }
 425
 426         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 427         if (i >= 0) {
 428                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 429                 max_childs = i;
 430         }
 431
 432         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 433         if (settle_pid > 0) {
 434                 info(udev, "udevd message (SETTLE) received\n");
 435         }
 436         udev_ctrl_msg_unref(ctrl_msg);
 437 }
 438
 439 /* read inotify messages */
 440 static int handle_inotify(struct udev *udev)
 441 {
 442         int nbytes, pos;
 443         char *buf;
 444         struct inotify_event *ev;
 445
 446         if ((ioctl(inotify_fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 447                 return 0;
 448
 449         buf = malloc(nbytes);
 450         if (buf == NULL) {
 451                 err(udev, "error getting buffer for inotify, disable watching\n");
 452                 close(inotify_fd);
 453                 inotify_fd = -1;
 454                 return 0;
 455         }
 456
 457         read(inotify_fd, buf, nbytes);
 458
 459         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 460                 struct udev_device *dev;
 461
 462                 ev = (struct inotify_event *)(buf + pos);
 463                 if (ev->len) {
 464                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 465                         reload_config = 1;
 466                         continue;
 467                 }
 468
 469                 dev = udev_watch_lookup(udev, ev->wd);
 470                 if (dev != NULL) {
 471                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 472                         if (ev->mask & IN_CLOSE_WRITE) {
 473                                 char filename[UTIL_PATH_SIZE];
 474                                 int fd;
 475
 476                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 477                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 478                                 fd = open(filename, O_WRONLY);
 479                                 if (fd < 0 || write(fd, "change", 6) < 0)
 480                                         info(udev, "error writing uevent: %m\n");
 481                                 close(fd);
 482                         }
 483                         if (ev->mask & IN_IGNORED)
 484                                 udev_watch_end(udev, dev);
 485
 486                         udev_device_unref(dev);
 487                 }
 488
 489         }
 490
 491         free (buf);
 492         return 0;
 493 }
 494
 495 static void sig_handler(int signum)
 496 {
 497         switch (signum) {
 498                 case SIGINT:
 499                 case SIGTERM:
 500                         udev_exit = 1;
 501                         break;
 502                 case SIGCHLD:
 503                         /* set flag, then write to pipe if needed */
 504                         sigchilds_waiting = 1;
 505                         break;
 506                 case SIGHUP:
 507                         reload_config = 1;
 508                         break;
 509         }
 510
 511         signal_received = 1;
 512 }
 513
 514 static void udev_done(int pid, int exitstatus)
 515 {
 516         struct udev_list_node *loop;
 517
 518         /* find event associated with pid and delete it */
 519         udev_list_node_foreach(loop, &event_list) {
 520                 struct udev_event *loop_event = node_to_event(loop);
 521
 522                 if (loop_event->pid == pid) {
 523                         info(loop_event->udev, "seq %llu cleanup, pid [%d], status %i, %ld seconds old\n",
 524                              udev_device_get_seqnum(loop_event->dev), loop_event->pid,
 525                              exitstatus, time(NULL) - loop_event->queue_time);
 526                         loop_event->exitstatus = exitstatus;
 527                         if (debug_trace)
 528                                 fprintf(stderr, "exit %s (%llu)\n",
 529                                        udev_device_get_syspath(loop_event->dev),
 530                                        udev_device_get_seqnum(loop_event->dev));
 531                         event_queue_delete(loop_event);
 532                         childs--;
 533
 534                         /* there may be dependent events waiting */
 535                         run_exec_q = 1;
 536                         return;
 537                 }
 538         }
 539 }
 540
 541 static void reap_sigchilds(void)
 542 {
 543         pid_t pid;
 544         int status;
 545
 546         while (1) {
 547                 pid = waitpid(-1, &status, WNOHANG);
 548                 if (pid <= 0)
 549                         break;
 550                 if (WIFEXITED(status))
 551                         status = WEXITSTATUS(status);
 552                 else if (WIFSIGNALED(status))
 553                         status = WTERMSIG(status) + 128;
 554                 else
 555                         status = 0;
 556                 udev_done(pid, status);
 557         }
 558 }
 559
 560 static void startup_log(struct udev *udev)
 561 {
 562         FILE *f;
 563         char path[UTIL_PATH_SIZE];
 564         struct stat statbuf;
 565
 566         f = fopen("/dev/kmsg", "w");
 567         if (f != NULL)
 568                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 569
 570         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 571         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 572                 const char *depr_str =
 573                         "udev: missing sysfs features; please update the kernel "
 574                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 575                         "udev may fail to work correctly";
 576
 577                 if (f != NULL)
 578                         fprintf(f, "<3>%s\n", depr_str);
 579                 err(udev, "%s\n", depr_str);
 580                 sleep(3);
 581         }
 582
 583         if (f != NULL)
 584                 fclose(f);
 585 }
 586
 587 int main(int argc, char *argv[])
 588 {
 589         struct udev *udev;
 590         int fd;
 591         struct sigaction act;
 592         const char *value;
 593         int daemonize = 0;
 594         int resolve_names = 1;
 595         static const struct option options[] = {
 596                 { "daemon", no_argument, NULL, 'd' },
 597                 { "debug-trace", no_argument, NULL, 't' },
 598                 { "debug", no_argument, NULL, 'D' },
 599                 { "help", no_argument, NULL, 'h' },
 600                 { "version", no_argument, NULL, 'V' },
 601                 { "resolve-names", required_argument, NULL, 'N' },
 602                 {}
 603         };
 604         int rc = 1;
 605
 606         udev = udev_new();
 607         if (udev == NULL)
 608                 goto exit;
 609
 610         logging_init("udevd");
 611         udev_set_log_fn(udev, log_fn);
 612         info(udev, "version %s\n", VERSION);
 613         udev_selinux_init(udev);
 614
 615         while (1) {
 616                 int option;
 617
 618                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 619                 if (option == -1)
 620                         break;
 621
 622                 switch (option) {
 623                 case 'd':
 624                         daemonize = 1;
 625                         break;
 626                 case 't':
 627                         debug_trace = 1;
 628                         break;
 629                 case 'D':
 630                         debug = 1;
 631                         if (udev_get_log_priority(udev) < LOG_INFO)
 632                                 udev_set_log_priority(udev, LOG_INFO);
 633                         break;
 634                 case 'N':
 635                         if (strcmp (optarg, "early") == 0) {
 636                                 resolve_names = 1;
 637                         } else if (strcmp (optarg, "late") == 0) {
 638                                 resolve_names = 0;
 639                         } else if (strcmp (optarg, "never") == 0) {
 640                                 resolve_names = -1;
 641                         } else {
 642                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 643                                 err(udev, "resolve-names must be early, late or never\n");
 644                                 goto exit;
 645                         }
 646                         break;
 647                 case 'h':
 648                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 649                                "[--resolve-names=early|late|never] [--version]\n");
 650                         goto exit;
 651                 case 'V':
 652                         printf("%s\n", VERSION);
 653                         goto exit;
 654                 default:
 655                         goto exit;
 656                 }
 657         }
 658
 659         if (getuid() != 0) {
 660                 fprintf(stderr, "root privileges required\n");
 661                 err(udev, "root privileges required\n");
 662                 goto exit;
 663         }
 664
 665         /* make sure std{in,out,err} fd's are in a sane state */
 666         fd = open("/dev/null", O_RDWR);
 667         if (fd < 0) {
 668                 fprintf(stderr, "cannot open /dev/null\n");
 669                 err(udev, "cannot open /dev/null\n");
 670         }
 671         if (write(STDOUT_FILENO, 0, 0) < 0)
 672                 dup2(fd, STDOUT_FILENO);
 673         if (write(STDERR_FILENO, 0, 0) < 0)
 674                 dup2(fd, STDERR_FILENO);
 675
 676         /* init control socket, bind() ensures, that only one udevd instance is running */
 677         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 678         if (udev_ctrl == NULL) {
 679                 fprintf(stderr, "error initializing control socket");
 680                 err(udev, "error initializing udevd socket");
 681                 rc = 1;
 682                 goto exit;
 683         }
 684
 685         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 686                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 687                 err(udev, "error binding control socket, seems udevd is already running\n");
 688                 rc = 1;
 689                 goto exit;
 690         }
 691
 692         kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 693         if (kernel_monitor == NULL || udev_monitor_enable_receiving(kernel_monitor) < 0) {
 694                 fprintf(stderr, "error initializing netlink socket\n");
 695                 err(udev, "error initializing netlink socket\n");
 696                 rc = 3;
 697                 goto exit;
 698         }
 699         udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 700
 701         rules = udev_rules_new(udev, resolve_names);
 702         if (rules == NULL) {
 703                 err(udev, "error reading rules\n");
 704                 goto exit;
 705         }
 706         udev_list_init(&event_list);
 707         udev_queue_export = udev_queue_export_new(udev);
 708         if (udev_queue_export == NULL) {
 709                 err(udev, "error creating queue file\n");
 710                 goto exit;
 711         }
 712
 713         if (daemonize) {
 714                 pid_t pid;
 715
 716                 pid = fork();
 717                 switch (pid) {
 718                 case 0:
 719                         dbg(udev, "daemonized fork running\n");
 720                         break;
 721                 case -1:
 722                         err(udev, "fork of daemon failed: %m\n");
 723                         rc = 4;
 724                         goto exit;
 725                 default:
 726                         dbg(udev, "child [%u] running, parent exits\n", pid);
 727                         rc = 0;
 728                         goto exit;
 729                 }
 730         }
 731
 732         /* redirect std{out,err} */
 733         if (!debug && !debug_trace) {
 734                 dup2(fd, STDIN_FILENO);
 735                 dup2(fd, STDOUT_FILENO);
 736                 dup2(fd, STDERR_FILENO);
 737         }
 738         if (fd > STDERR_FILENO)
 739                 close(fd);
 740
 741         /* set scheduling priority for the daemon */
 742         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 743
 744         chdir("/");
 745         umask(022);
 746         setsid();
 747
 748         /* OOM_DISABLE == -17 */
 749         fd = open("/proc/self/oom_adj", O_RDWR);
 750         if (fd < 0)
 751                 err(udev, "error disabling OOM: %m\n");
 752         else {
 753                 write(fd, "-17", 3);
 754                 close(fd);
 755         }
 756
 757         startup_log(udev);
 758
 759         /* set signal handlers */
 760         memset(&act, 0x00, sizeof(struct sigaction));
 761         act.sa_handler = sig_handler;
 762         sigemptyset(&act.sa_mask);
 763         act.sa_flags = SA_RESTART;
 764         sigaction(SIGINT, &act, NULL);
 765         sigaction(SIGTERM, &act, NULL);
 766         sigaction(SIGCHLD, &act, NULL);
 767         sigaction(SIGHUP, &act, NULL);
 768
 769         /* watch rules directory */
 770         udev_watch_init(udev);
 771         if (inotify_fd >= 0) {
 772                 if (udev_get_rules_path(udev) != NULL) {
 773                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 774                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 775                 } else {
 776                         char filename[UTIL_PATH_SIZE];
 777
 778                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 779                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 780                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 781                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 782
 783                         /* watch dynamic rules directory */
 784                         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 785                         inotify_add_watch(inotify_fd, filename,
 786                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 787                 }
 788
 789                 udev_watch_restore(udev);
 790         }
 791
 792         /* in trace mode run one event after the other */
 793         if (debug_trace) {
 794                 max_childs = 1;
 795         } else {
 796                 int memsize = mem_size_mb();
 797                 if (memsize > 0)
 798                         max_childs = 128 + (memsize / 4);
 799                 else
 800                         max_childs = UDEVD_MAX_CHILDS;
 801         }
 802         /* possibly overwrite maximum limit of executed events */
 803         value = getenv("UDEVD_MAX_CHILDS");
 804         if (value)
 805                 max_childs = strtoul(value, NULL, 10);
 806         info(udev, "initialize max_childs to %u\n", max_childs);
 807
 808         while (!udev_exit) {
 809                 sigset_t blocked_mask, orig_mask;
 810                 struct pollfd pfd[4];
 811                 struct pollfd *ctrl_poll, *monitor_poll, *inotify_poll = NULL;
 812                 int nfds = 0;
 813                 int fdcount;
 814
 815                 sigfillset(&blocked_mask);
 816                 sigprocmask(SIG_SETMASK, &blocked_mask, &orig_mask);
 817                 if (signal_received) {
 818                         sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 819                         goto handle_signals;
 820                 }
 821
 822                 ctrl_poll = &pfd[nfds++];
 823                 ctrl_poll->fd = udev_ctrl_get_fd(udev_ctrl);
 824                 ctrl_poll->events = POLLIN;
 825
 826                 monitor_poll = &pfd[nfds++];
 827                 monitor_poll->fd = udev_monitor_get_fd(kernel_monitor);
 828                 monitor_poll->events = POLLIN;
 829
 830                 if (inotify_fd >= 0) {
 831                         inotify_poll = &pfd[nfds++];
 832                         inotify_poll->fd = inotify_fd;
 833                         inotify_poll->events = POLLIN;
 834                 }
 835
 836                 fdcount = ppoll(pfd, nfds, NULL, &orig_mask);
 837                 sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 838                 if (fdcount < 0) {
 839                         if (errno == EINTR)
 840                                 goto handle_signals;
 841                         err(udev, "error in select: %m\n");
 842                         continue;
 843                 }
 844
 845                 /* get control message */
 846                 if (ctrl_poll->revents & POLLIN)
 847                         handle_ctrl_msg(udev_ctrl);
 848
 849                 /* get kernel uevent */
 850                 if (monitor_poll->revents & POLLIN) {
 851                         struct udev_device *dev;
 852
 853                         dev = udev_monitor_receive_device(kernel_monitor);
 854                         if (dev != NULL) {
 855                                 struct udev_event *event;
 856
 857                                 event = udev_event_new(dev);
 858                                 if (event != NULL)
 859                                         event_queue_insert(event);
 860                                 else
 861                                         udev_device_unref(dev);
 862                         }
 863                 }
 864
 865                 /* rules directory inotify watch */
 866                 if (inotify_poll && (inotify_poll->revents & POLLIN))
 867                         handle_inotify(udev);
 868
 869 handle_signals:
 870                 signal_received = 0;
 871
 872                 /* rules changed, set by inotify or a HUP signal */
 873                 if (reload_config) {
 874                         struct udev_rules *rules_new;
 875
 876                         reload_config = 0;
 877                         rules_new = udev_rules_new(udev, resolve_names);
 878                         if (rules_new != NULL) {
 879                                 udev_rules_unref(rules);
 880                                 rules = rules_new;
 881                         }
 882                 }
 883
 884                 if (sigchilds_waiting) {
 885                         sigchilds_waiting = 0;
 886                         reap_sigchilds();
 887                 }
 888
 889                 if (run_exec_q) {
 890                         run_exec_q = 0;
 891                         if (!stop_exec_q)
 892                                 event_queue_manager(udev);
 893                 }
 894
 895                 if (settle_pid > 0) {
 896                         kill(settle_pid, SIGUSR1);
 897                         settle_pid = 0;
 898                 }
 899         }
 900         udev_queue_export_cleanup(udev_queue_export);
 901         rc = 0;
 902 exit:
 903
 904         udev_queue_export_unref(udev_queue_export);
 905         udev_rules_unref(rules);
 906         udev_ctrl_unref(udev_ctrl);
 907         if (inotify_fd >= 0)
 908                 close(inotify_fd);
 909         udev_monitor_unref(kernel_monitor);
 910         udev_selinux_exit(udev);
 911         udev_unref(udev);
 912         logging_close();
 913         return rc;
 914 }