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_ctrl *udev_ctrl;
  69 static struct udev_monitor *kernel_monitor;
  70 static volatile sig_atomic_t sigchilds_waiting;
  71 static volatile sig_atomic_t udev_exit;
  72 static volatile sig_atomic_t reload_config;
  73 static volatile sig_atomic_t signal_received;
  74 static volatile pid_t settle_pid;
  75 static int run_exec_q;
  76 static int stop_exec_q;
  77 static int max_childs;
  78 static int childs;
  79 static struct udev_list_node event_list;
  80
  81 enum event_state {
  82         EVENT_QUEUED,
  83         EVENT_FINISHED,
  84         EVENT_FAILED,
  85 };
  86
  87 static struct udev_event *node_to_event(struct udev_list_node *node)
  88 {
  89         char *event;
  90
  91         event = (char *)node;
  92         event -= offsetof(struct udev_event, node);
  93         return (struct udev_event *)event;
  94 }
  95
  96 static void export_event_state(struct udev_event *event, enum event_state state)
  97 {
  98         char filename[UTIL_PATH_SIZE];
  99         char filename_failed[UTIL_PATH_SIZE];
 100         char *s;
 101         size_t l;
 102
 103         /* location of queue file */
 104         snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu",
 105                  udev_get_dev_path(event->udev), udev_device_get_seqnum(event->dev));
 106
 107         /* location of failed file */
 108         s = filename_failed;
 109         l = util_strpcpyl(&s, sizeof(filename_failed), udev_get_dev_path(event->udev), "/.udev/failed/", NULL);
 110         util_path_encode(udev_device_get_devpath(event->dev), s, l);
 111
 112         switch (state) {
 113         case EVENT_QUEUED:
 114                 if(unlink(filename_failed) == 0)
 115                         util_delete_path(event->udev, filename_failed);
 116                 util_create_path(event->udev, filename);
 117                 udev_selinux_setfscreatecon(event->udev, filename, S_IFLNK);
 118                 symlink(udev_device_get_devpath(event->dev), filename);
 119                 udev_selinux_resetfscreatecon(event->udev);
 120                 break;
 121         case EVENT_FINISHED:
 122                 if (udev_device_get_devpath_old(event->dev) != NULL) {
 123                         /* "move" event - rename failed file to current name, do not delete failed */
 124                         char filename_failed_old[UTIL_PATH_SIZE];
 125
 126                         s = filename_failed_old;
 127                         l = util_strpcpyl(&s, sizeof(filename_failed_old), udev_get_dev_path(event->udev), "/.udev/failed/", NULL);
 128                         util_path_encode(udev_device_get_devpath_old(event->dev), s, l);
 129                         if (rename(filename_failed_old, filename_failed) == 0)
 130                                 info(event->udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 131                                      udev_device_get_devpath_old(event->dev), udev_device_get_devpath(event->dev));
 132                 } else {
 133                         if (unlink(filename_failed) == 0)
 134                                 util_delete_path(event->udev, filename_failed);
 135                 }
 136
 137                 unlink(filename);
 138
 139                 /* clean up possibly empty queue directory */
 140                 if (udev_list_is_empty(&event_list))
 141                         util_delete_path(event->udev, filename);
 142                 break;
 143         case EVENT_FAILED:
 144                 /* move failed event to the failed directory */
 145                 util_create_path(event->udev, filename_failed);
 146                 rename(filename, filename_failed);
 147
 148                 /* clean up possibly empty queue directory */
 149                 if (udev_list_is_empty(&event_list))
 150                         util_delete_path(event->udev, filename);
 151                 break;
 152         }
 153
 154         return;
 155 }
 156
 157 static void event_queue_delete(struct udev_event *event)
 158 {
 159         udev_list_node_remove(&event->node);
 160
 161         /* mark as failed, if "add" event returns non-zero */
 162         if (event->exitstatus && strcmp(udev_device_get_action(event->dev), "add") == 0)
 163                 export_event_state(event, EVENT_FAILED);
 164         else
 165                 export_event_state(event, EVENT_FINISHED);
 166
 167         udev_device_unref(event->dev);
 168         udev_event_unref(event);
 169 }
 170
 171 static void event_sig_handler(int signum)
 172 {
 173         if (signum == SIGALRM)
 174                 _exit(1);
 175 }
 176
 177 static void event_fork(struct udev_event *event)
 178 {
 179         pid_t pid;
 180         struct sigaction act;
 181         int err;
 182
 183 #if 0
 184         /* single process, no forking, just for testing/profiling */
 185         err = udev_event_execute_rules(event, rules);
 186         if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 187                 udev_event_execute_run(event);
 188         info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 189         event_queue_delete(event);
 190         return;
 191 #endif
 192
 193         if (debug_trace) {
 194                 event->trace = 1;
 195                 fprintf(stderr, "fork %s (%llu)\n",
 196                        udev_device_get_syspath(event->dev),
 197                        udev_device_get_seqnum(event->dev));
 198         }
 199
 200         pid = fork();
 201         switch (pid) {
 202         case 0:
 203                 /* child */
 204                 udev_ctrl_unref(udev_ctrl);
 205                 logging_close();
 206                 logging_init("udevd-event");
 207                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 208
 209                 /* set signal handlers */
 210                 memset(&act, 0x00, sizeof(act));
 211                 act.sa_handler = event_sig_handler;
 212                 sigemptyset (&act.sa_mask);
 213                 act.sa_flags = 0;
 214                 sigaction(SIGALRM, &act, NULL);
 215
 216                 /* reset to default */
 217                 act.sa_handler = SIG_DFL;
 218                 sigaction(SIGINT, &act, NULL);
 219                 sigaction(SIGTERM, &act, NULL);
 220                 sigaction(SIGCHLD, &act, NULL);
 221                 sigaction(SIGHUP, &act, NULL);
 222
 223                 /* set timeout to prevent hanging processes */
 224                 alarm(UDEV_EVENT_TIMEOUT);
 225
 226                 /* apply rules, create node, symlinks */
 227                 err = udev_event_execute_rules(event, rules);
 228
 229                 /* rules may change/disable the timeout */
 230                 if (udev_device_get_event_timeout(event->dev) >= 0)
 231                         alarm(udev_device_get_event_timeout(event->dev));
 232
 233                 /* execute RUN= */
 234                 if (err == 0 && !event->ignore_device && udev_get_run(event->udev))
 235                         udev_event_execute_run(event);
 236
 237                 /* apply/restore inotify watch */
 238                 if (err == 0 && event->inotify_watch) {
 239                         udev_watch_begin(event->udev, event->dev);
 240                         udev_device_update_db(event->dev);
 241                 }
 242
 243                 /* send processed event back to the kernel netlink socket */
 244                 udev_monitor_send_device(kernel_monitor, event->dev);
 245
 246                 info(event->udev, "seq %llu exit with %i\n", udev_device_get_seqnum(event->dev), err);
 247                 logging_close();
 248                 if (err != 0)
 249                         exit(1);
 250                 exit(0);
 251         case -1:
 252                 err(event->udev, "fork of child failed: %m\n");
 253                 event_queue_delete(event);
 254                 break;
 255         default:
 256                 /* get SIGCHLD in main loop */
 257                 info(event->udev, "seq %llu forked, pid [%d], '%s' '%s', %ld seconds old\n",
 258                      udev_device_get_seqnum(event->dev),
 259                      pid,
 260                      udev_device_get_action(event->dev),
 261                      udev_device_get_subsystem(event->dev),
 262                      time(NULL) - event->queue_time);
 263                 event->pid = pid;
 264                 childs++;
 265         }
 266 }
 267
 268 static void event_queue_insert(struct udev_event *event)
 269 {
 270         char filename[UTIL_PATH_SIZE];
 271         int fd;
 272
 273         event->queue_time = time(NULL);
 274
 275         export_event_state(event, EVENT_QUEUED);
 276         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(event->dev),
 277              udev_device_get_action(event->dev), udev_device_get_subsystem(event->dev));
 278
 279         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(event->udev), "/.udev/uevent_seqnum", NULL);
 280         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 281         if (fd >= 0) {
 282                 char str[32];
 283                 int len;
 284
 285                 len = sprintf(str, "%llu\n", udev_device_get_seqnum(event->dev));
 286                 write(fd, str, len);
 287                 close(fd);
 288         }
 289
 290
 291         udev_list_node_append(&event->node, &event_list);
 292         run_exec_q = 1;
 293
 294         /* run all events with a timeout set immediately */
 295         if (udev_device_get_timeout(event->dev) > 0) {
 296                 event_fork(event);
 297                 return;
 298         }
 299 }
 300
 301 static int mem_size_mb(void)
 302 {
 303         FILE *f;
 304         char buf[4096];
 305         long int memsize = -1;
 306
 307         f = fopen("/proc/meminfo", "r");
 308         if (f == NULL)
 309                 return -1;
 310
 311         while (fgets(buf, sizeof(buf), f) != NULL) {
 312                 long int value;
 313
 314                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 315                         memsize = value / 1024;
 316                         break;
 317                 }
 318         }
 319
 320         fclose(f);
 321         return memsize;
 322 }
 323
 324 static int compare_devpath(const char *running, const char *waiting)
 325 {
 326         int i = 0;
 327
 328         while (running[i] != '\0' && running[i] == waiting[i])
 329                 i++;
 330
 331         /* identical device event found */
 332         if (running[i] == '\0' && waiting[i] == '\0')
 333                 return 1;
 334
 335         /* parent device event found */
 336         if (running[i] == '\0' && waiting[i] == '/')
 337                 return 2;
 338
 339         /* child device event found */
 340         if (running[i] == '/' && waiting[i] == '\0')
 341                 return 3;
 342
 343         /* no matching event */
 344         return 0;
 345 }
 346
 347 /* lookup event for identical, parent, child device */
 348 static int devpath_busy(struct udev_event *event)
 349 {
 350         struct udev_list_node *loop;
 351
 352         /* check if queue contains events we depend on */
 353         udev_list_node_foreach(loop, &event_list) {
 354                 struct udev_event *loop_event = node_to_event(loop);
 355
 356                 /* we already found a later event, earlier can not block us, no need to check again */
 357                 if (udev_device_get_seqnum(loop_event->dev) < event->delaying_seqnum)
 358                         continue;
 359
 360                 /* event we checked earlier still exists, no need to check again */
 361                 if (udev_device_get_seqnum(loop_event->dev) == event->delaying_seqnum)
 362                         return 2;
 363
 364                 /* found ourself, no later event can block us */
 365                 if (udev_device_get_seqnum(loop_event->dev) >= udev_device_get_seqnum(event->dev))
 366                         break;
 367
 368                 /* check our old name */
 369                 if (udev_device_get_devpath_old(event->dev) != NULL)
 370                         if (strcmp(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath_old(event->dev)) == 0) {
 371                                 event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 372                                 return 3;
 373                         }
 374
 375                 /* check identical, parent, or child device event */
 376                 if (compare_devpath(udev_device_get_devpath(loop_event->dev), udev_device_get_devpath(event->dev)) != 0) {
 377                         dbg(event->udev, "%llu, device event still pending %llu (%s)\n",
 378                             udev_device_get_seqnum(event->dev),
 379                             udev_device_get_seqnum(loop_event->dev),
 380                             udev_device_get_devpath(loop_event->dev));
 381                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 382                         return 4;
 383                 }
 384
 385                 /* check for our major:minor number */
 386                 if (major(udev_device_get_devnum(event->dev)) > 0 &&
 387                     udev_device_get_devnum(loop_event->dev) == udev_device_get_devnum(event->dev) &&
 388                     strcmp(udev_device_get_subsystem(event->dev), udev_device_get_subsystem(loop_event->dev)) == 0) {
 389                         dbg(event->udev, "%llu, device event still pending %llu (%d:%d)\n",
 390                             udev_device_get_seqnum(event->dev),
 391                             udev_device_get_seqnum(loop_event->dev),
 392                             major(udev_device_get_devnum(loop_event->dev)), minor(udev_device_get_devnum(loop_event->dev)));
 393                         event->delaying_seqnum = udev_device_get_seqnum(loop_event->dev);
 394                         return 5;
 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 start_over:
 407         if (udev_list_is_empty(&event_list)) {
 408                 if (childs > 0) {
 409                         err(udev, "event list empty, but childs count is %i", childs);
 410                         childs = 0;
 411                 }
 412                 return;
 413         }
 414
 415         udev_list_node_foreach_safe(loop, tmp, &event_list) {
 416                 struct udev_event *loop_event = node_to_event(loop);
 417
 418                 if (childs >= max_childs) {
 419                         info(udev, "maximum number (%i) of childs reached\n", childs);
 420                         break;
 421                 }
 422
 423                 if (loop_event->pid != 0)
 424                         continue;
 425
 426                 /* do not start event if parent or child event is still running */
 427                 if (devpath_busy(loop_event) != 0) {
 428                         dbg(udev, "delay seq %llu (%s)\n",
 429                             udev_device_get_seqnum(loop_event->dev),
 430                             udev_device_get_devpath(loop_event->dev));
 431                         continue;
 432                 }
 433
 434                 event_fork(loop_event);
 435                 dbg(udev, "moved seq %llu to running list\n", udev_device_get_seqnum(loop_event->dev));
 436
 437                 /* retry if events finished in the meantime */
 438                 if (sigchilds_waiting) {
 439                         sigchilds_waiting = 0;
 440                         reap_sigchilds();
 441                         goto start_over;
 442                 }
 443         }
 444 }
 445
 446 /* receive the udevd message from userspace */
 447 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 448 {
 449         struct udev *udev = udev_ctrl_get_udev(uctrl);
 450         struct udev_ctrl_msg *ctrl_msg;
 451         const char *str;
 452         int i;
 453
 454         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 455         if (ctrl_msg == NULL)
 456                 return;
 457
 458         i = udev_ctrl_get_set_log_level(ctrl_msg);
 459         if (i >= 0) {
 460                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 461                 udev_set_log_priority(udev, i);
 462         }
 463
 464         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 465                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 466                 stop_exec_q = 1;
 467         }
 468
 469         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 470                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 471                 stop_exec_q = 0;
 472                 event_queue_manager(udev);
 473         }
 474
 475         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 476                 info(udev, "udevd message (RELOAD_RULES) received\n");
 477                 reload_config = 1;
 478         }
 479
 480         str = udev_ctrl_get_set_env(ctrl_msg);
 481         if (str != NULL) {
 482                 char *key;
 483
 484                 key = strdup(str);
 485                 if (key != NULL) {
 486                         char *val;
 487
 488                         val = strchr(key, '=');
 489                         if (val != NULL) {
 490                                 val[0] = '\0';
 491                                 val = &val[1];
 492                                 if (val[0] == '\0') {
 493                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 494                                         udev_add_property(udev, key, NULL);
 495                                 } else {
 496                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 497                                         udev_add_property(udev, key, val);
 498                                 }
 499                         } else {
 500                                 err(udev, "wrong key format '%s'\n", key);
 501                         }
 502                         free(key);
 503                 }
 504         }
 505
 506         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 507         if (i >= 0) {
 508                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 509                 max_childs = i;
 510         }
 511
 512         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 513         if (settle_pid > 0) {
 514                 info(udev, "udevd message (SETTLE) received\n");
 515         }
 516         udev_ctrl_msg_unref(ctrl_msg);
 517 }
 518
 519 /* read inotify messages */
 520 static int handle_inotify(struct udev *udev)
 521 {
 522         int nbytes, pos;
 523         char *buf;
 524         struct inotify_event *ev;
 525
 526         if ((ioctl(inotify_fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 527                 return 0;
 528
 529         buf = malloc(nbytes);
 530         if (buf == NULL) {
 531                 err(udev, "error getting buffer for inotify, disable watching\n");
 532                 close(inotify_fd);
 533                 inotify_fd = -1;
 534                 return 0;
 535         }
 536
 537         read(inotify_fd, buf, nbytes);
 538
 539         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 540                 struct udev_device *dev;
 541
 542                 ev = (struct inotify_event *)(buf + pos);
 543                 if (ev->len) {
 544                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 545                         reload_config = 1;
 546                         continue;
 547                 }
 548
 549                 dev = udev_watch_lookup(udev, ev->wd);
 550                 if (dev != NULL) {
 551                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 552                         if (ev->mask & IN_CLOSE_WRITE) {
 553                                 char filename[UTIL_PATH_SIZE];
 554                                 int fd;
 555
 556                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 557                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 558                                 fd = open(filename, O_WRONLY);
 559                                 if (fd < 0 || write(fd, "change", 6) < 0)
 560                                         info(udev, "error writing uevent: %m\n");
 561                                 close(fd);
 562                         }
 563                         if (ev->mask & IN_IGNORED)
 564                                 udev_watch_end(udev, dev);
 565
 566                         udev_device_unref(dev);
 567                 }
 568
 569         }
 570
 571         free (buf);
 572         return 0;
 573 }
 574
 575 static void sig_handler(int signum)
 576 {
 577         switch (signum) {
 578                 case SIGINT:
 579                 case SIGTERM:
 580                         udev_exit = 1;
 581                         break;
 582                 case SIGCHLD:
 583                         /* set flag, then write to pipe if needed */
 584                         sigchilds_waiting = 1;
 585                         break;
 586                 case SIGHUP:
 587                         reload_config = 1;
 588                         break;
 589         }
 590
 591         signal_received = 1;
 592 }
 593
 594 static void udev_done(int pid, int exitstatus)
 595 {
 596         struct udev_list_node *loop;
 597
 598         /* find event associated with pid and delete it */
 599         udev_list_node_foreach(loop, &event_list) {
 600                 struct udev_event *loop_event = node_to_event(loop);
 601
 602                 if (loop_event->pid == pid) {
 603                         info(loop_event->udev, "seq %llu cleanup, pid [%d], status %i, %ld seconds old\n",
 604                              udev_device_get_seqnum(loop_event->dev), loop_event->pid,
 605                              exitstatus, time(NULL) - loop_event->queue_time);
 606                         loop_event->exitstatus = exitstatus;
 607                         if (debug_trace)
 608                                 fprintf(stderr, "exit %s (%llu)\n",
 609                                        udev_device_get_syspath(loop_event->dev),
 610                                        udev_device_get_seqnum(loop_event->dev));
 611                         event_queue_delete(loop_event);
 612                         childs--;
 613
 614                         /* there may be dependent events waiting */
 615                         run_exec_q = 1;
 616                         return;
 617                 }
 618         }
 619 }
 620
 621 static void reap_sigchilds(void)
 622 {
 623         pid_t pid;
 624         int status;
 625
 626         while (1) {
 627                 pid = waitpid(-1, &status, WNOHANG);
 628                 if (pid <= 0)
 629                         break;
 630                 if (WIFEXITED(status))
 631                         status = WEXITSTATUS(status);
 632                 else if (WIFSIGNALED(status))
 633                         status = WTERMSIG(status) + 128;
 634                 else
 635                         status = 0;
 636                 udev_done(pid, status);
 637         }
 638 }
 639
 640 static void cleanup_queue_dir(struct udev *udev)
 641 {
 642         char dirname[UTIL_PATH_SIZE];
 643         char filename[UTIL_PATH_SIZE];
 644         DIR *dir;
 645
 646         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/uevent_seqnum", NULL);
 647         unlink(filename);
 648
 649         util_strscpyl(dirname, sizeof(dirname), udev_get_dev_path(udev), "/.udev/queue", NULL);
 650         dir = opendir(dirname);
 651         if (dir != NULL) {
 652                 while (1) {
 653                         struct dirent *dent;
 654
 655                         dent = readdir(dir);
 656                         if (dent == NULL || dent->d_name[0] == '\0')
 657                                 break;
 658                         if (dent->d_name[0] == '.')
 659                                 continue;
 660                         unlinkat(dirfd(dir), dent->d_name, 0);
 661                 }
 662                 closedir(dir);
 663                 rmdir(dirname);
 664         }
 665 }
 666
 667 static void export_initial_seqnum(struct udev *udev)
 668 {
 669         char filename[UTIL_PATH_SIZE];
 670         int fd;
 671         char seqnum[32];
 672         ssize_t len = 0;
 673
 674         util_strscpyl(filename, sizeof(filename), udev_get_sys_path(udev), "/kernel/uevent_seqnum", NULL);
 675         fd = open(filename, O_RDONLY);
 676         if (fd >= 0) {
 677                 len = read(fd, seqnum, sizeof(seqnum)-1);
 678                 close(fd);
 679         }
 680         if (len <= 0) {
 681                 strcpy(seqnum, "0\n");
 682                 len = 3;
 683         }
 684         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/uevent_seqnum", NULL);
 685         util_create_path(udev, filename);
 686         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 687         if (fd >= 0) {
 688                 write(fd, seqnum, len);
 689                 close(fd);
 690         }
 691 }
 692
 693 static void startup_log(struct udev *udev)
 694 {
 695         FILE *f;
 696         char path[UTIL_PATH_SIZE];
 697         struct stat statbuf;
 698
 699         f = fopen("/dev/kmsg", "w");
 700         if (f != NULL)
 701                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 702
 703         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 704         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 705                 const char *depr_str =
 706                         "udev: missing sysfs features; please update the kernel "
 707                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 708                         "udev may fail to work correctly";
 709
 710                 if (f != NULL)
 711                         fprintf(f, "<3>%s\n", depr_str);
 712                 err(udev, "%s\n", depr_str);
 713                 sleep(3);
 714         }
 715
 716         if (f != NULL)
 717                 fclose(f);
 718 }
 719
 720 int main(int argc, char *argv[])
 721 {
 722         struct udev *udev;
 723         int fd;
 724         struct sigaction act;
 725         const char *value;
 726         int daemonize = 0;
 727         int resolve_names = 1;
 728         static const struct option options[] = {
 729                 { "daemon", no_argument, NULL, 'd' },
 730                 { "debug-trace", no_argument, NULL, 't' },
 731                 { "debug", no_argument, NULL, 'D' },
 732                 { "help", no_argument, NULL, 'h' },
 733                 { "version", no_argument, NULL, 'V' },
 734                 { "resolve-names", required_argument, NULL, 'N' },
 735                 {}
 736         };
 737         int rc = 1;
 738
 739         udev = udev_new();
 740         if (udev == NULL)
 741                 goto exit;
 742
 743         logging_init("udevd");
 744         udev_set_log_fn(udev, log_fn);
 745         info(udev, "version %s\n", VERSION);
 746         udev_selinux_init(udev);
 747
 748         while (1) {
 749                 int option;
 750
 751                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 752                 if (option == -1)
 753                         break;
 754
 755                 switch (option) {
 756                 case 'd':
 757                         daemonize = 1;
 758                         break;
 759                 case 't':
 760                         debug_trace = 1;
 761                         break;
 762                 case 'D':
 763                         debug = 1;
 764                         if (udev_get_log_priority(udev) < LOG_INFO)
 765                                 udev_set_log_priority(udev, LOG_INFO);
 766                         break;
 767                 case 'N':
 768                         if (strcmp (optarg, "early") == 0) {
 769                                 resolve_names = 1;
 770                         } else if (strcmp (optarg, "late") == 0) {
 771                                 resolve_names = 0;
 772                         } else if (strcmp (optarg, "never") == 0) {
 773                                 resolve_names = -1;
 774                         } else {
 775                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 776                                 err(udev, "resolve-names must be early, late or never\n");
 777                                 goto exit;
 778                         }
 779                         break;
 780                 case 'h':
 781                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 782                                "[--resolve-names=early|late|never] [--version]\n");
 783                         goto exit;
 784                 case 'V':
 785                         printf("%s\n", VERSION);
 786                         goto exit;
 787                 default:
 788                         goto exit;
 789                 }
 790         }
 791
 792         if (getuid() != 0) {
 793                 fprintf(stderr, "root privileges required\n");
 794                 err(udev, "root privileges required\n");
 795                 goto exit;
 796         }
 797
 798         /* make sure std{in,out,err} fd's are in a sane state */
 799         fd = open("/dev/null", O_RDWR);
 800         if (fd < 0) {
 801                 fprintf(stderr, "cannot open /dev/null\n");
 802                 err(udev, "cannot open /dev/null\n");
 803         }
 804         if (write(STDOUT_FILENO, 0, 0) < 0)
 805                 dup2(fd, STDOUT_FILENO);
 806         if (write(STDERR_FILENO, 0, 0) < 0)
 807                 dup2(fd, STDERR_FILENO);
 808
 809         /* init control socket, bind() ensures, that only one udevd instance is running */
 810         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 811         if (udev_ctrl == NULL) {
 812                 fprintf(stderr, "error initializing control socket");
 813                 err(udev, "error initializing udevd socket");
 814                 rc = 1;
 815                 goto exit;
 816         }
 817
 818         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 819                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 820                 err(udev, "error binding control socket, seems udevd is already running\n");
 821                 rc = 1;
 822                 goto exit;
 823         }
 824
 825         kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 826         if (kernel_monitor == NULL || udev_monitor_enable_receiving(kernel_monitor) < 0) {
 827                 fprintf(stderr, "error initializing netlink socket\n");
 828                 err(udev, "error initializing netlink socket\n");
 829                 rc = 3;
 830                 goto exit;
 831         }
 832         udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 833
 834         rules = udev_rules_new(udev, resolve_names);
 835         if (rules == NULL) {
 836                 err(udev, "error reading rules\n");
 837                 goto exit;
 838         }
 839         udev_list_init(&event_list);
 840         cleanup_queue_dir(udev);
 841         export_initial_seqnum(udev);
 842
 843         if (daemonize) {
 844                 pid_t pid;
 845
 846                 pid = fork();
 847                 switch (pid) {
 848                 case 0:
 849                         dbg(udev, "daemonized fork running\n");
 850                         break;
 851                 case -1:
 852                         err(udev, "fork of daemon failed: %m\n");
 853                         rc = 4;
 854                         goto exit;
 855                 default:
 856                         dbg(udev, "child [%u] running, parent exits\n", pid);
 857                         rc = 0;
 858                         goto exit;
 859                 }
 860         }
 861
 862         /* redirect std{out,err} */
 863         if (!debug && !debug_trace) {
 864                 dup2(fd, STDIN_FILENO);
 865                 dup2(fd, STDOUT_FILENO);
 866                 dup2(fd, STDERR_FILENO);
 867         }
 868         if (fd > STDERR_FILENO)
 869                 close(fd);
 870
 871         /* set scheduling priority for the daemon */
 872         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 873
 874         chdir("/");
 875         umask(022);
 876         setsid();
 877
 878         /* OOM_DISABLE == -17 */
 879         fd = open("/proc/self/oom_adj", O_RDWR);
 880         if (fd < 0)
 881                 err(udev, "error disabling OOM: %m\n");
 882         else {
 883                 write(fd, "-17", 3);
 884                 close(fd);
 885         }
 886
 887         startup_log(udev);
 888
 889         /* set signal handlers */
 890         memset(&act, 0x00, sizeof(struct sigaction));
 891         act.sa_handler = sig_handler;
 892         sigemptyset(&act.sa_mask);
 893         act.sa_flags = SA_RESTART;
 894         sigaction(SIGINT, &act, NULL);
 895         sigaction(SIGTERM, &act, NULL);
 896         sigaction(SIGCHLD, &act, NULL);
 897         sigaction(SIGHUP, &act, NULL);
 898
 899         /* watch rules directory */
 900         udev_watch_init(udev);
 901         if (inotify_fd >= 0) {
 902                 if (udev_get_rules_path(udev) != NULL) {
 903                         inotify_add_watch(inotify_fd, udev_get_rules_path(udev),
 904                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 905                 } else {
 906                         char filename[UTIL_PATH_SIZE];
 907
 908                         inotify_add_watch(inotify_fd, UDEV_PREFIX "/lib/udev/rules.d",
 909                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 910                         inotify_add_watch(inotify_fd, SYSCONFDIR "/udev/rules.d",
 911                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 912
 913                         /* watch dynamic rules directory */
 914                         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 915                         inotify_add_watch(inotify_fd, filename,
 916                                           IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 917                 }
 918
 919                 udev_watch_restore(udev);
 920         }
 921
 922         /* in trace mode run one event after the other */
 923         if (debug_trace) {
 924                 max_childs = 1;
 925         } else {
 926                 int memsize = mem_size_mb();
 927                 if (memsize > 0)
 928                         max_childs = 128 + (memsize / 4);
 929                 else
 930                         max_childs = UDEVD_MAX_CHILDS;
 931         }
 932         /* possibly overwrite maximum limit of executed events */
 933         value = getenv("UDEVD_MAX_CHILDS");
 934         if (value)
 935                 max_childs = strtoul(value, NULL, 10);
 936         info(udev, "initialize max_childs to %u\n", max_childs);
 937
 938         while (!udev_exit) {
 939                 sigset_t blocked_mask, orig_mask;
 940                 struct pollfd pfd[4];
 941                 struct pollfd *ctrl_poll, *monitor_poll, *inotify_poll = NULL;
 942                 int nfds = 0;
 943                 int fdcount;
 944
 945                 sigfillset(&blocked_mask);
 946                 sigprocmask(SIG_SETMASK, &blocked_mask, &orig_mask);
 947                 if (signal_received) {
 948                         sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 949                         goto handle_signals;
 950                 }
 951
 952                 ctrl_poll = &pfd[nfds++];
 953                 ctrl_poll->fd = udev_ctrl_get_fd(udev_ctrl);
 954                 ctrl_poll->events = POLLIN;
 955
 956                 monitor_poll = &pfd[nfds++];
 957                 monitor_poll->fd = udev_monitor_get_fd(kernel_monitor);
 958                 monitor_poll->events = POLLIN;
 959
 960                 if (inotify_fd >= 0) {
 961                         inotify_poll = &pfd[nfds++];
 962                         inotify_poll->fd = inotify_fd;
 963                         inotify_poll->events = POLLIN;
 964                 }
 965
 966                 fdcount = ppoll(pfd, nfds, NULL, &orig_mask);
 967                 sigprocmask(SIG_SETMASK, &orig_mask, NULL);
 968                 if (fdcount < 0) {
 969                         if (errno == EINTR)
 970                                 goto handle_signals;
 971                         err(udev, "error in select: %m\n");
 972                         continue;
 973                 }
 974
 975                 /* get control message */
 976                 if (ctrl_poll->revents & POLLIN)
 977                         handle_ctrl_msg(udev_ctrl);
 978
 979                 /* get kernel uevent */
 980                 if (monitor_poll->revents & POLLIN) {
 981                         struct udev_device *dev;
 982
 983                         dev = udev_monitor_receive_device(kernel_monitor);
 984                         if (dev != NULL) {
 985                                 struct udev_event *event;
 986
 987                                 event = udev_event_new(dev);
 988                                 if (event != NULL)
 989                                         event_queue_insert(event);
 990                                 else
 991                                         udev_device_unref(dev);
 992                         }
 993                 }
 994
 995                 /* rules directory inotify watch */
 996                 if (inotify_poll && (inotify_poll->revents & POLLIN))
 997                         handle_inotify(udev);
 998
 999 handle_signals:
1000                 signal_received = 0;
1001
1002                 /* rules changed, set by inotify or a HUP signal */
1003                 if (reload_config) {
1004                         struct udev_rules *rules_new;
1005
1006                         reload_config = 0;
1007                         rules_new = udev_rules_new(udev, resolve_names);
1008                         if (rules_new != NULL) {
1009                                 udev_rules_unref(rules);
1010                                 rules = rules_new;
1011                         }
1012                 }
1013
1014                 if (sigchilds_waiting) {
1015                         sigchilds_waiting = 0;
1016                         reap_sigchilds();
1017                 }
1018
1019                 if (run_exec_q) {
1020                         run_exec_q = 0;
1021                         if (!stop_exec_q)
1022                                 event_queue_manager(udev);
1023                 }
1024
1025                 if (settle_pid > 0) {
1026                         kill(settle_pid, SIGUSR1);
1027                         settle_pid = 0;
1028                 }
1029         }
1030         cleanup_queue_dir(udev);
1031         rc = 0;
1032 exit:
1033         udev_rules_unref(rules);
1034         udev_ctrl_unref(udev_ctrl);
1035         if (inotify_fd >= 0)
1036                 close(inotify_fd);
1037         udev_monitor_unref(kernel_monitor);
1038         udev_selinux_exit(udev);
1039         udev_unref(udev);
1040         logging_close();
1041         return rc;
1042 }