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  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <stddef.h>
  20 #include <signal.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <ctype.h>
  27 #include <fcntl.h>
  28 #include <time.h>
  29 #include <getopt.h>
  30 #include <sys/select.h>
  31 #include <sys/wait.h>
  32 #include <sys/stat.h>
  33 #include <sys/ioctl.h>
  34 #ifdef HAVE_INOTIFY
  35 #include <sys/inotify.h>
  36 #endif
  37
  38 #include "udev.h"
  39
  40 #define UDEVD_PRIORITY                  -4
  41 #define UDEV_PRIORITY                   -2
  42
  43 /* maximum limit of forked childs */
  44 #define UDEVD_MAX_CHILDS                256
  45
  46 static int debug;
  47
  48 static void log_fn(struct udev *udev, int priority,
  49                    const char *file, int line, const char *fn,
  50                    const char *format, va_list args)
  51 {
  52         if (debug) {
  53                 fprintf(stderr, "[%d] %s: ", (int) getpid(), fn);
  54                 vfprintf(stderr, format, args);
  55         } else {
  56                 vsyslog(priority, format, args);
  57         }
  58 }
  59
  60 static int debug_trace;
  61 static struct udev_rules *rules;
  62 static struct udev_ctrl *udev_ctrl;
  63 static struct udev_monitor *kernel_monitor;
  64 static int inotify_fd = -1;
  65 static int signal_pipe[2] = {-1, -1};
  66 static volatile int sigchilds_waiting;
  67 static volatile int udev_exit;
  68 static volatile int reload_config;
  69 static int run_exec_q;
  70 static int stop_exec_q;
  71 static int max_childs;
  72 static int childs;
  73 static struct udev_list_node event_list;
  74
  75 enum event_state {
  76         EVENT_QUEUED,
  77         EVENT_FINISHED,
  78         EVENT_FAILED,
  79 };
  80
  81 static struct udev_event *node_to_event(struct udev_list_node *node)
  82 {
  83         char *event;
  84
  85         event = (char *)node;
  86         event -= offsetof(struct udev_event, node);
  87         return (struct udev_event *)event;
  88 }
  89
  90 static void export_event_state(struct udev_event *event, enum event_state state)
  91 {
  92         char filename[UTIL_PATH_SIZE];
  93         char filename_failed[UTIL_PATH_SIZE];
  94         size_t start;
  95
  96         /* location of queue file */
  97         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu",
  98                  udev_get_dev_path(event->udev), udev_device_get_seqnum(event->dev));
  99
 100         /* location of failed file */
 101         util_strlcpy(filename_failed, udev_get_dev_path(event->udev), sizeof(filename_failed));
 102         util_strlcat(filename_failed, "/", sizeof(filename_failed));
 103         start = util_strlcat(filename_failed, ".udev/failed/", sizeof(filename_failed));
 104         util_strlcat(filename_failed, udev_device_get_devpath(event->dev), sizeof(filename_failed));
 105         util_path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 106
 107         switch (state) {
 108         case EVENT_QUEUED:
 109                 if(unlink(filename_failed) == 0)
 110                         util_delete_path(event->udev, filename_failed);
 111                 util_create_path(event->udev, filename);
 112                 udev_selinux_setfscreatecon(event->udev, filename, S_IFLNK);
 113                 symlink(udev_device_get_devpath(event->dev), filename);
 114                 udev_selinux_resetfscreatecon(event->udev);
 115                 break;
 116         case EVENT_FINISHED:
 117                 if (udev_device_get_devpath_old(event->dev) != NULL) {
 118                         /* "move" event - rename failed file to current name, do not delete failed */
 119                         char filename_failed_old[UTIL_PATH_SIZE];
 120
 121                         util_strlcpy(filename_failed_old, udev_get_dev_path(event->udev), sizeof(filename_failed_old));
 122                         util_strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 123                         start = util_strlcat(filename_failed_old, ".udev/failed/", sizeof(filename_failed_old));
 124                         util_strlcat(filename_failed_old, udev_device_get_devpath_old(event->dev), sizeof(filename_failed_old));
 125                         util_path_encode(&filename_failed_old[start], sizeof(filename) - start);
 126
 127                         if (rename(filename_failed_old, filename_failed) == 0)
 128                                 info(event->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 129                                      udev_device_get_devpath_old(event->dev), udev_device_get_devpath(event->dev));
 130                 } else {
 131                         if (unlink(filename_failed) == 0)
 132                                 util_delete_path(event->udev, filename_failed);
 133                 }
 134
 135                 unlink(filename);
 136
 137                 /* clean up possibly empty queue directory */
 138                 if (udev_list_is_empty(&event_list))
 139                         util_delete_path(event->udev, filename);
 140                 break;
 141         case EVENT_FAILED:
 142                 /* move failed event to the failed directory */
 143                 util_create_path(event->udev, filename_failed);
 144                 rename(filename, filename_failed);
 145
 146                 /* clean up possibly empty queue directory */
 147                 if (udev_list_is_empty(&event_list))
 148                         util_delete_path(event->udev, filename);
 149                 break;
 150         }
 151
 152         return;
 153 }
 154
 155 static void event_queue_delete(struct udev_event *event)
 156 {
 157         udev_list_node_remove(&event->node);
 158
 159         /* mark as failed, if "add" event returns non-zero */
 160         if (event->exitstatus && strcmp(udev_device_get_action(event->dev), "add") == 0)
 161                 export_event_state(event, EVENT_FAILED);
 162         else
 163                 export_event_state(event, EVENT_FINISHED);
 164
 165         udev_device_unref(event->dev);
 166         udev_event_unref(event);
 167 }
 168
 169 static void asmlinkage event_sig_handler(int signum)
 170 {
 171         if (signum == SIGALRM)
 172                 exit(1);
 173 }
 174
 175 static void event_fork(struct udev_event *event)
 176 {
 177         pid_t pid;
 178         struct sigaction act;
 179         int err;
 180
 181         if (debug_trace) {
 182                 event->trace = 1;
 183                 printf("fork %s (%llu)\n",
 184                        udev_device_get_syspath(event->dev),
 185                        udev_device_get_seqnum(event->dev));
 186         }
 187
 188         pid = fork();
 189         switch (pid) {
 190         case 0:
 191                 /* child */
 192                 udev_monitor_unref(kernel_monitor);
 193                 udev_ctrl_unref(udev_ctrl);
 194                 if (inotify_fd >= 0)
 195                         close(inotify_fd);
 196                 close(signal_pipe[READ_END]);
 197                 close(signal_pipe[WRITE_END]);
 198                 logging_close();
 199                 logging_init("udevd-event");
 200                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 201
 202                 /* set signal handlers */
 203                 memset(&act, 0x00, sizeof(act));
 204                 act.sa_handler = (void (*)(int)) event_sig_handler;
 205                 sigemptyset (&act.sa_mask);
 206                 act.sa_flags = 0;
 207                 sigaction(SIGALRM, &act, NULL);
 208
 209                 /* reset to default */
 210                 act.sa_handler = SIG_DFL;
 211                 sigaction(SIGINT, &act, NULL);
 212                 sigaction(SIGTERM, &act, NULL);
 213                 sigaction(SIGCHLD, &act, NULL);
 214                 sigaction(SIGHUP, &act, NULL);
 215
 216                 /* set timeout to prevent hanging processes */
 217                 alarm(UDEV_EVENT_TIMEOUT);
 218
 219                 /* apply rules, create node, symlinks */
 220                 err = udev_event_execute_rules(event, rules);
 221
 222                 /* rules may change/disable the timeout */
 223                 if (udev_device_get_event_timeout(event->dev) >= 0)
 224                         alarm(udev_device_get_event_timeout(event->dev));
 225
 226                 /* execute RUN= */
 227                 if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 228                         udev_event_execute_run(event);
 229
 230                 info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 231                 logging_close();
 232                 if (err != 0)
 233                         exit(1);
 234                 exit(0);
 235         case -1:
 236                 err(event->udev, "fork of child failed: %m\n");
 237                 event_queue_delete(event);
 238                 break;
 239         default:
 240                 /* get SIGCHLD in main loop */
 241                 info(event->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 242                      udev_device_get_seqnum(event->dev),
 243                      pid,
 244                      udev_device_get_action(event->dev),
 245                      udev_device_get_subsystem(event->dev),
 246                      time(NULL) - event->queue_time);
 247                 event->pid = pid;
 248                 childs++;
 249         }
 250 }
 251
 252 static void event_queue_insert(struct udev_event *event)
 253 {
 254         char filename[UTIL_PATH_SIZE];
 255         int fd;
 256
 257         event->queue_time = time(NULL);
 258
 259         export_event_state(event, EVENT_QUEUED);
 260         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(event->dev),
 261              udev_device_get_action(event->dev), udev_device_get_subsystem(event->dev));
 262
 263         util_strlcpy(filename, udev_get_dev_path(event->udev), sizeof(filename));
 264         util_strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 265         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 266         if (fd >= 0) {
 267                 char str[32];
 268                 int len;
 269
 270                 len = sprintf(str, "%llu\n", udev_device_get_seqnum(event->dev));
 271                 write(fd, str, len);
 272                 close(fd);
 273         }
 274
 275
 276         udev_list_node_append(&event->node, &event_list);
 277         run_exec_q = 1;
 278
 279         /* run all events with a timeout set immediately */
 280         if (udev_device_get_timeout(event->dev) > 0) {
 281                 event_fork(event);
 282                 return;
 283         }
 284 }
 285
 286 static int mem_size_mb(void)
 287 {
 288         FILE* f;
 289         char buf[4096];
 290         long int memsize = -1;
 291
 292         f = fopen("/proc/meminfo", "r");
 293         if (f == NULL)
 294                 return -1;
 295
 296         while (fgets(buf, sizeof(buf), f) != NULL) {
 297                 long int value;
 298
 299                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 300                         memsize = value / 1024;
 301                         break;
 302                 }
 303         }
 304
 305         fclose(f);
 306         return memsize;
 307 }
 308
 309 static int compare_devpath(const char *running, const char *waiting)
 310 {
 311         int i = 0;
 312
 313         while (running[i] != '\0' && running[i] == waiting[i])
 314                 i++;
 315
 316         /* identical device event found */
 317         if (running[i] == '\0' && waiting[i] == '\0')
 318                 return 1;
 319
 320         /* parent device event found */
 321         if (running[i] == '\0' && waiting[i] == '/')
 322                 return 2;
 323
 324         /* child device event found */
 325         if (running[i] == '/' && waiting[i] == '\0')
 326                 return 3;
 327
 328         /* no matching event */
 329         return 0;
 330 }
 331
 332 /* lookup event for identical, parent, child, or physical device */
 333 static int devpath_busy(struct udev_event *event)
 334 {
 335         struct udev_list_node *loop;
 336
 337         if (event->delaying_seqnum > 0) {
 338         }
 339         /* check if queue contains events we depend on */
 340         udev_list_node_foreach(loop, &event_list) {
 341                 struct udev_event *loop_event = node_to_event(loop);
 342
 343                 /* we already found a later event, earlier can not block us, no need to check again */
 344                 if (udev_device_get_seqnum(loop_event->dev) < event->delaying_seqnum)
 345                         continue;
 346
 347                 /* event we checked earlier still exists, no need to check again */
 348                 if (udev_device_get_seqnum(loop_event->dev) == event->delaying_seqnum)
 349                         return 2;
 350
 351                 /* found ourself, no later event can block us */
 352                 if (udev_device_get_seqnum(loop_event->dev) >= udev_device_get_seqnum(event->dev))
 353                         break;
 354
 355                 /* check our old name */
 356                 if (udev_device_get_devpath_old(event->dev) != NULL)
 357                         if (strcmp(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath_old(event->dev)) == 0) {
 358                                 event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 359                                 return 3;
 360                         }
 361
 362                 /* check identical, parent, or child device event */
 363                 if (compare_devpath(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath(event->dev)) != 0) {
 364                         dbg(event->udev, "%llu, device event still pending %llu (%s)\n",
 365                             udev_device_get_seqnum(event->dev),
 366                             udev_device_get_seqnum(loop_event->dev),
 367                             udev_device_get_devpath(loop_event->dev));
 368                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 369                         return 4;
 370                 }
 371
 372                 /* check for our major:minor number */
 373                 if (major(udev_device_get_devnum(event->dev)) > 0 &&
 374                     udev_device_get_devnum(loop_event->dev) == udev_device_get_devnum(event->dev) &&
 375                     strcmp(udev_device_get_subsystem(event->dev), udev_device_get_subsystem(loop_event->dev)) == 0) {
 376                         dbg(event->udev, "%llu, device event still pending %llu (%d:%d)\n",
 377                             udev_device_get_seqnum(event->dev),
 378                             udev_device_get_seqnum(loop_event->dev),
 379                             major(udev_device_get_devnum(loop_event->dev)), minor(udev_device_get_devnum(loop_event->dev)));
 380                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 381                         return 5;
 382                 }
 383
 384                 /* check physical device event (special case of parent) */
 385                 if (udev_device_get_physdevpath(event->dev) != NULL &&
 386                     strcmp(udev_device_get_action(event->dev), "add") == 0)
 387                         if (compare_devpath(udev_device_get_devpath(loop_event->dev),
 388                                             udev_device_get_physdevpath(event->dev)) != 0) {
 389                                 dbg(event->udev, "%llu, physical device event still pending %llu (%s)\n",
 390                                     udev_device_get_seqnum(event->dev),
 391                                     udev_device_get_seqnum(loop_event->dev),
 392                                     udev_device_get_devpath(loop_event->dev));
 393                                 event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 394                                 return 6;
 395                         }
 396         }
 397         return 0;
 398 }
 399
 400 /* serializes events for the identical and parent and child devices */
 401 static void event_queue_manager(struct udev *udev)
 402 {
 403         struct udev_list_node *loop;
 404         struct udev_list_node *tmp;
 405
 406         if (udev_list_is_empty(&event_list)) {
 407                 if (childs > 0) {
 408                         err(udev, "event list empty, but childs count is %i", childs);
 409                         childs = 0;
 410                 }
 411                 return;
 412         }
 413
 414         udev_list_node_foreach_safe(loop, tmp, &event_list) {
 415                 struct udev_event *loop_event = node_to_event(loop);
 416
 417                 if (childs >= max_childs) {
 418                         info(udev, "maximum number (%i) of childs reached\n", childs);
 419                         break;
 420                 }
 421
 422                 if (loop_event->pid != 0)
 423                         continue;
 424
 425                 /* do not start event if parent or child event is still running */
 426                 if (devpath_busy(loop_event) != 0) {
 427                         dbg(udev, "delay seq %llu (%s)\n",
 428                             udev_device_get_seqnum(loop_event->dev),
 429                             udev_device_get_devpath(loop_event->dev));
 430                         continue;
 431                 }
 432
 433                 /* do dendencies, start event */
 434                 event_fork(loop_event);
 435                 dbg(udev, "moved seq %llu to running list\n", udev_device_get_seqnum(loop_event->dev));
 436         }
 437 }
 438
 439 /* receive the udevd message from userspace */
 440 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 441 {
 442         struct udev *udev = udev_ctrl_get_udev(uctrl);
 443         struct udev_ctrl_msg *ctrl_msg;
 444         const char *str;
 445         int i;
 446
 447         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 448         if (ctrl_msg == NULL)
 449                 return;
 450
 451         i = udev_ctrl_get_set_log_level(ctrl_msg);
 452         if (i >= 0) {
 453                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 454                 udev_set_log_priority(udev, i);
 455         }
 456
 457         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 458                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 459                 stop_exec_q = 1;
 460         }
 461
 462         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 463                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 464                 stop_exec_q = 0;
 465                 event_queue_manager(udev);
 466         }
 467
 468         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 469                 info(udev, "udevd message (RELOAD_RULES) received\n");
 470                 reload_config = 1;
 471         }
 472
 473         str = udev_ctrl_get_set_env(ctrl_msg);
 474         if (str != NULL) {
 475                 char *key;
 476
 477                 key = strdup(str);
 478                 if (key != NULL) {
 479                         char *val;
 480
 481                         val = strchr(key, '=');
 482                         if (val != NULL) {
 483                                 val[0] = '\0';
 484                                 val = &val[1];
 485                                 if (val[0] == '\0') {
 486                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 487                                         udev_add_property(udev, key, NULL);
 488                                 } else {
 489                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 490                                         udev_add_property(udev, key, val);
 491                                 }
 492                         } else {
 493                                 err(udev, "wrong key format '%s'\n", key);
 494                         }
 495                         free(key);
 496                 }
 497         }
 498
 499         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 500         if (i >= 0) {
 501                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 502                 max_childs = i;
 503         }
 504         udev_ctrl_msg_unref(ctrl_msg);
 505 }
 506
 507 static void asmlinkage sig_handler(int signum)
 508 {
 509         switch (signum) {
 510                 case SIGINT:
 511                 case SIGTERM:
 512                         udev_exit = 1;
 513                         break;
 514                 case SIGCHLD:
 515                         /* set flag, then write to pipe if needed */
 516                         sigchilds_waiting = 1;
 517                         break;
 518                 case SIGHUP:
 519                         reload_config = 1;
 520                         break;
 521         }
 522
 523         /* write to pipe, which will wakeup select() in our mainloop */
 524         write(signal_pipe[WRITE_END], "", 1);
 525 }
 526
 527 static void udev_done(int pid, int exitstatus)
 528 {
 529         struct udev_list_node *loop;
 530
 531         /* find event associated with pid and delete it */
 532         udev_list_node_foreach(loop, &event_list) {
 533                 struct udev_event *loop_event = node_to_event(loop);
 534
 535                 if (loop_event->pid == pid) {
 536                         info(loop_event->udev, "seq %llu cleanup, pid [%d], status %i, %ld seconds old\n",
 537                              udev_device_get_seqnum(loop_event->dev), loop_event->pid,
 538                              exitstatus, time(NULL) - loop_event->queue_time);
 539                         loop_event->exitstatus = exitstatus;
 540                         if (debug_trace)
 541                                 printf("exit %s (%llu)\n",
 542                                        udev_device_get_syspath(loop_event->dev),
 543                                        udev_device_get_seqnum(loop_event->dev));
 544                         event_queue_delete(loop_event);
 545                         childs--;
 546
 547                         /* there may be dependent events waiting */
 548                         run_exec_q = 1;
 549                         return;
 550                 }
 551         }
 552 }
 553
 554 static void reap_sigchilds(void)
 555 {
 556         pid_t pid;
 557         int status;
 558
 559         while (1) {
 560                 pid = waitpid(-1, &status, WNOHANG);
 561                 if (pid <= 0)
 562                         break;
 563                 if (WIFEXITED(status))
 564                         status = WEXITSTATUS(status);
 565                 else if (WIFSIGNALED(status))
 566                         status = WTERMSIG(status) + 128;
 567                 else
 568                         status = 0;
 569                 udev_done(pid, status);
 570         }
 571 }
 572
 573 static void export_initial_seqnum(struct udev *udev)
 574 {
 575         char filename[UTIL_PATH_SIZE];
 576         int fd;
 577         char seqnum[32];
 578         ssize_t len = 0;
 579
 580         util_strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 581         util_strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 582         fd = open(filename, O_RDONLY);
 583         if (fd >= 0) {
 584                 len = read(fd, seqnum, sizeof(seqnum)-1);
 585                 close(fd);
 586         }
 587         if (len <= 0) {
 588                 strcpy(seqnum, "0\n");
 589                 len = 3;
 590         }
 591         util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 592         util_strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 593         util_create_path(udev, filename);
 594         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 595         if (fd >= 0) {
 596                 write(fd, seqnum, len);
 597                 close(fd);
 598         }
 599 }
 600
 601 int main(int argc, char *argv[])
 602 {
 603         struct udev *udev;
 604         int err;
 605         int fd;
 606         struct sigaction act;
 607         fd_set readfds;
 608         const char *value;
 609         int daemonize = 0;
 610         static const struct option options[] = {
 611                 { "daemon", no_argument, NULL, 'd' },
 612                 { "debug-trace", no_argument, NULL, 't' },
 613                 { "debug", no_argument, NULL, 'D' },
 614                 { "help", no_argument, NULL, 'h' },
 615                 { "version", no_argument, NULL, 'V' },
 616                 {}
 617         };
 618         int rc = 1;
 619         int maxfd;
 620
 621         udev = udev_new();
 622         if (udev == NULL)
 623                 goto exit;
 624
 625         logging_init("udevd");
 626         udev_set_log_fn(udev, log_fn);
 627         info(udev, "version %s\n", VERSION);
 628         udev_selinux_init(udev);
 629
 630         while (1) {
 631                 int option;
 632
 633                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 634                 if (option == -1)
 635                         break;
 636
 637                 switch (option) {
 638                 case 'd':
 639                         daemonize = 1;
 640                         break;
 641                 case 't':
 642                         debug_trace = 1;
 643                         break;
 644                 case 'D':
 645                         debug = 1;
 646                         if (udev_get_log_priority(udev) < LOG_INFO)
 647                                 udev_set_log_priority(udev, LOG_INFO);
 648                         break;
 649                 case 'h':
 650                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] [--version]\n");
 651                         goto exit;
 652                 case 'V':
 653                         printf("%s\n", VERSION);
 654                         goto exit;
 655                 default:
 656                         goto exit;
 657                 }
 658         }
 659
 660         if (getuid() != 0) {
 661                 fprintf(stderr, "root privileges required\n");
 662                 err(udev, "root privileges required\n");
 663                 goto exit;
 664         }
 665
 666         /* make sure std{in,out,err} fd's are in a sane state */
 667         fd = open("/dev/null", O_RDWR);
 668         if (fd < 0) {
 669                 fprintf(stderr, "cannot open /dev/null\n");
 670                 err(udev, "cannot open /dev/null\n");
 671         }
 672         if (write(STDOUT_FILENO, 0, 0) < 0)
 673                 dup2(fd, STDOUT_FILENO);
 674         if (write(STDERR_FILENO, 0, 0) < 0)
 675                 dup2(fd, STDERR_FILENO);
 676
 677         /* init control socket, bind() ensures, that only one udevd instance is running */
 678         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 679         if (udev_ctrl == NULL) {
 680                 fprintf(stderr, "error initializing control socket");
 681                 err(udev, "error initializing udevd socket");
 682                 rc = 1;
 683                 goto exit;
 684         }
 685
 686         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 687                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 688                 err(udev, "error binding control socket, seems udevd is already running\n");
 689                 rc = 1;
 690                 goto exit;
 691         }
 692
 693         kernel_monitor = udev_monitor_new_from_netlink(udev);
 694         if (kernel_monitor == NULL || udev_monitor_enable_receiving(kernel_monitor) < 0) {
 695                 fprintf(stderr, "error initializing netlink socket\n");
 696                 err(udev, "error initializing netlink socket\n");
 697                 rc = 3;
 698                 goto exit;
 699         }
 700         udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 701
 702         err = pipe(signal_pipe);
 703         if (err < 0) {
 704                 err(udev, "error getting pipes: %m\n");
 705                 goto exit;
 706         }
 707
 708         err = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 709         if (err < 0) {
 710                 err(udev, "error fcntl on read pipe: %m\n");
 711                 goto exit;
 712         }
 713         err = fcntl(signal_pipe[READ_END], F_SETFL, err | O_NONBLOCK);
 714         if (err < 0) {
 715                 err(udev, "error fcntl on read pipe: %m\n");
 716                 goto exit;
 717         }
 718
 719         err = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 720         if (err < 0) {
 721                 err(udev, "error fcntl on write pipe: %m\n");
 722                 goto exit;
 723         }
 724         err = fcntl(signal_pipe[WRITE_END], F_SETFL, err | O_NONBLOCK);
 725         if (err < 0) {
 726                 err(udev, "error fcntl on write pipe: %m\n");
 727                 goto exit;
 728         }
 729
 730         rules = udev_rules_new(udev, 1);
 731         if (rules == NULL) {
 732                 err(udev, "error reading rules\n");
 733                 goto exit;
 734         }
 735         udev_list_init(&event_list);
 736         export_initial_seqnum(udev);
 737
 738         if (daemonize) {
 739                 pid_t pid;
 740
 741                 pid = fork();
 742                 switch (pid) {
 743                 case 0:
 744                         dbg(udev, "daemonized fork running\n");
 745                         break;
 746                 case -1:
 747                         err(udev, "fork of daemon failed: %m\n");
 748                         rc = 4;
 749                         goto exit;
 750                 default:
 751                         dbg(udev, "child [%u] running, parent exits\n", pid);
 752                         rc = 0;
 753                         goto exit;
 754                 }
 755         }
 756
 757         /* redirect std{out,err} */
 758         if (!debug && !debug_trace) {
 759                 dup2(fd, STDIN_FILENO);
 760                 dup2(fd, STDOUT_FILENO);
 761                 dup2(fd, STDERR_FILENO);
 762         }
 763         if (fd > STDERR_FILENO)
 764                 close(fd);
 765
 766         /* set scheduling priority for the daemon */
 767         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 768
 769         chdir("/");
 770         umask(022);
 771         setsid();
 772
 773         /* OOM_DISABLE == -17 */
 774         fd = open("/proc/self/oom_adj", O_RDWR);
 775         if (fd < 0)
 776                 err(udev, "error disabling OOM: %m\n");
 777         else {
 778                 write(fd, "-17", 3);
 779                 close(fd);
 780         }
 781
 782         fd = open("/dev/kmsg", O_WRONLY);
 783         if (fd > 0) {
 784                 const char *ver_str = "<6>udev: starting version " VERSION "\n";
 785                 char path[UTIL_PATH_SIZE];
 786                 struct stat statbuf;
 787
 788                 write(fd, ver_str, strlen(ver_str));
 789                 util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 790                 util_strlcat(path, "/class/mem/null", sizeof(path));
 791                 if (lstat(path, &statbuf) == 0) {
 792                         if (S_ISDIR(statbuf.st_mode)) {
 793                                 const char *depr_str = "<6>udev: deprecated sysfs layout (kernel too old, "
 794                                                         "or CONFIG_SYSFS_DEPRECATED) is unsupported, some "
 795                                                         "udev features may fail\n";
 796
 797                                 write(fd, depr_str, strlen(depr_str));
 798                         }
 799                 }
 800                 close(fd);
 801         }
 802
 803         /* set signal handlers */
 804         memset(&act, 0x00, sizeof(struct sigaction));
 805         act.sa_handler = (void (*)(int)) sig_handler;
 806         sigemptyset(&act.sa_mask);
 807         act.sa_flags = SA_RESTART;
 808         sigaction(SIGINT, &act, NULL);
 809         sigaction(SIGTERM, &act, NULL);
 810         sigaction(SIGCHLD, &act, NULL);
 811         sigaction(SIGHUP, &act, NULL);
 812
 813         /* watch rules directory */
 814         inotify_fd = inotify_init();
 815         if (inotify_fd >= 0) {
 816                 if (udev_get_rules_path(udev) != NULL) {
 817                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 818                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 819                 } else {
 820                         char filename[UTIL_PATH_SIZE];
 821
 822                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 823                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 824                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 825                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 826
 827                         /* watch dynamic rules directory */
 828                         util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 829                         util_strlcat(filename, "/.udev/rules.d", sizeof(filename));
 830                         inotify_add_watch(inotify_fd, filename,
 831                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 832                 }
 833         } else if (errno == ENOSYS)
 834                 err(udev, "the kernel does not support inotify, udevd can't monitor rules file changes\n");
 835         else
 836                 err(udev, "inotify_init failed: %m\n");
 837
 838         /* in trace mode run one event after the other */
 839         if (debug_trace) {
 840                 max_childs = 1;
 841         } else {
 842                 int memsize = mem_size_mb();
 843                 if (memsize > 0)
 844                         max_childs = 128 + (memsize / 4);
 845                 else
 846                         max_childs = UDEVD_MAX_CHILDS;
 847         }
 848         /* possibly overwrite maximum limit of executed events */
 849         value = getenv("UDEVD_MAX_CHILDS");
 850         if (value)
 851                 max_childs = strtoul(value, NULL, 10);
 852         info(udev, "initialize max_childs to %u\n", max_childs);
 853
 854         maxfd = udev_ctrl_get_fd(udev_ctrl);
 855         maxfd = UDEV_MAX(maxfd, udev_monitor_get_fd(kernel_monitor));
 856         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
 857         maxfd = UDEV_MAX(maxfd, inotify_fd);
 858         while (!udev_exit) {
 859                 int fdcount;
 860
 861                 FD_ZERO(&readfds);
 862                 FD_SET(signal_pipe[READ_END], &readfds);
 863                 FD_SET(udev_ctrl_get_fd(udev_ctrl), &readfds);
 864                 FD_SET(udev_monitor_get_fd(kernel_monitor), &readfds);
 865                 if (inotify_fd >= 0)
 866                         FD_SET(inotify_fd, &readfds);
 867                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
 868                 if (fdcount < 0) {
 869                         if (errno != EINTR)
 870                                 err(udev, "error in select: %m\n");
 871                         continue;
 872                 }
 873
 874                 /* get control message */
 875                 if (FD_ISSET(udev_ctrl_get_fd(udev_ctrl), &readfds))
 876                         handle_ctrl_msg(udev_ctrl);
 877
 878                 /* get kernel uevent */
 879                 if (FD_ISSET(udev_monitor_get_fd(kernel_monitor), &readfds)) {
 880                         struct udev_device *dev;
 881
 882                         dev = udev_monitor_receive_device(kernel_monitor);
 883                         if (dev != NULL) {
 884                                 struct udev_event *event;
 885
 886                                 event = udev_event_new(dev);
 887                                 if (event != NULL)
 888                                         event_queue_insert(event);
 889                                 else
 890                                         udev_device_unref(dev);
 891                         }
 892                 }
 893
 894                 /* received a signal, clear our notification pipe */
 895                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
 896                         char buf[256];
 897
 898                         read(signal_pipe[READ_END], &buf, sizeof(buf));
 899                 }
 900
 901                 /* rules directory inotify watch */
 902                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
 903                         int nbytes;
 904
 905                         /* discard all possible events, we can just reload the config */
 906                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
 907                                 char *buf;
 908
 909                                 reload_config = 1;
 910                                 buf = malloc(nbytes);
 911                                 if (buf == NULL) {
 912                                         err(udev, "error getting buffer for inotify, disable watching\n");
 913                                         close(inotify_fd);
 914                                         inotify_fd = -1;
 915                                 }
 916                                 read(inotify_fd, buf, nbytes);
 917                                 free(buf);
 918                         }
 919                 }
 920
 921                 /* rules changed, set by inotify or a HUP signal */
 922                 if (reload_config) {
 923                         struct udev_rules *rules_new;
 924
 925                         reload_config = 0;
 926                         rules_new = udev_rules_new(udev, 1);
 927                         if (rules_new != NULL) {
 928                                 udev_rules_unref(rules);
 929                                 rules = rules_new;
 930                         }
 931                 }
 932
 933                 if (sigchilds_waiting) {
 934                         sigchilds_waiting = 0;
 935                         reap_sigchilds();
 936                 }
 937
 938                 if (run_exec_q) {
 939                         run_exec_q = 0;
 940                         if (!stop_exec_q)
 941                                 event_queue_manager(udev);
 942                 }
 943         }
 944         rc = 0;
 945
 946 exit:
 947         udev_rules_unref(rules);
 948
 949         if (signal_pipe[READ_END] >= 0)
 950                 close(signal_pipe[READ_END]);
 951         if (signal_pipe[WRITE_END] >= 0)
 952                 close(signal_pipe[WRITE_END]);
 953
 954         udev_ctrl_unref(udev_ctrl);
 955         if (inotify_fd >= 0)
 956                 close(inotify_fd);
 957         udev_monitor_unref(kernel_monitor);
 958
 959         udev_selinux_exit(udev);
 960         udev_unref(udev);
 961         logging_close();
 962         return rc;
 963 }