udev/lib/libudev-device.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <dirent.h>
  27 #include <fcntl.h>
  28 #include <sys/stat.h>
  29
  30 #include "libudev.h"
  31 #include "libudev-private.h"
  32
  33 struct udev_device {
  34         int refcount;
  35         struct udev *udev;
  36         struct udev_device *parent_device;
  37         char *syspath;
  38         const char *devpath;
  39         const char *sysname;
  40         char *devnode;
  41         char *subsystem;
  42         struct list_node devlink_list;
  43         struct list_node properties_list;
  44         char *action;
  45         int event_timeout;
  46         char *driver;
  47         char *devpath_old;
  48         char *physdevpath;
  49         int timeout;
  50         dev_t devnum;
  51         unsigned long long int seqnum;
  52         int num_fake_partitions;
  53         int devlink_priority;
  54         int ignore_remove;
  55         struct list_node attr_list;
  56         int info_loaded;
  57 };
  58
  59 static size_t syspath_to_db_path(struct udev_device *udev_device, char *filename, size_t len)
  60 {
  61         size_t start;
  62
  63         /* translate to location of db file */
  64         util_strlcpy(filename, udev_get_dev_path(udev_device->udev), len);
  65         start = util_strlcat(filename, "/.udev/db/", len);
  66         util_strlcat(filename, udev_device->devpath, len);
  67         return util_path_encode(&filename[start], len - start);
  68 }
  69
  70 static int device_read_db(struct udev_device *udev_device)
  71 {
  72         struct stat stats;
  73         char filename[UTIL_PATH_SIZE];
  74         char line[UTIL_LINE_SIZE];
  75         FILE *f;
  76
  77         syspath_to_db_path(udev_device, filename, sizeof(filename));
  78
  79         if (lstat(filename, &stats) != 0) {
  80                 info(udev_device->udev, "no db file to read %s: %m\n", filename);
  81                 return -1;
  82         }
  83         if ((stats.st_mode & S_IFMT) == S_IFLNK) {
  84                 char target[UTIL_PATH_SIZE];
  85                 int target_len;
  86
  87                 target_len = readlink(filename, target, sizeof(target));
  88                 if (target_len > 0)
  89                         target[target_len] = '\0';
  90                 else {
  91                         info(udev_device->udev, "error reading db link %s: %m\n", filename);
  92                         return -1;
  93                 }
  94                 if (asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
  95                         return -ENOMEM;
  96                 info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
  97                 return 0;
  98         }
  99
 100         f = fopen(filename, "r");
 101         if (f == NULL) {
 102                 info(udev_device->udev, "error reading db file %s: %m\n", filename);
 103                 return -1;
 104         }
 105         while (fgets(line, sizeof(line), f)) {
 106                 ssize_t len;
 107                 const char *val;
 108
 109                 len = strlen(line);
 110                 if (len < 4)
 111                         break;
 112                 line[len-1] = '\0';
 113                 val = &line[2];
 114
 115                 switch(line[0]) {
 116                 case 'N':
 117                         asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), val);
 118                         break;
 119                 case 'S':
 120                         util_strlcpy(filename, udev_get_dev_path(udev_device->udev), sizeof(filename));
 121                         util_strlcat(filename, "/", sizeof(filename));
 122                         util_strlcat(filename, val, sizeof(filename));
 123                         device_add_devlink(udev_device, filename);
 124                         break;
 125                 case 'L':
 126                         device_set_devlink_priority(udev_device, atoi(val));
 127                         break;
 128                 case 'T':
 129                         device_set_event_timeout(udev_device, atoi(val));
 130                         break;
 131                 case 'A':
 132                         device_set_num_fake_partitions(udev_device, atoi(val));
 133                         break;
 134                 case 'R':
 135                         device_set_ignore_remove(udev_device, atoi(val));
 136                         break;
 137                 case 'E':
 138                         device_add_property_from_string(udev_device, val);
 139                         break;
 140                 }
 141         }
 142         fclose(f);
 143
 144         info(udev_device->udev, "device %p filled with db file data\n", udev_device);
 145         return 0;
 146 }
 147
 148 static int device_read_uevent_file(struct udev_device *udev_device)
 149 {
 150         char filename[UTIL_PATH_SIZE];
 151         FILE *f;
 152         char line[UTIL_LINE_SIZE];
 153         int maj = 0;
 154         int min = 0;
 155
 156         util_strlcpy(filename, udev_device->syspath, sizeof(filename));
 157         util_strlcat(filename, "/uevent", sizeof(filename));
 158         f = fopen(filename, "r");
 159         if (f == NULL)
 160                 return -1;
 161
 162         while (fgets(line, sizeof(line), f)) {
 163                 char *pos;
 164
 165                 pos = strchr(line, '\n');
 166                 if (pos == NULL)
 167                         continue;
 168                 pos[0] = '\0';
 169
 170                 if (strncmp(line, "MAJOR=", 6) == 0)
 171                         maj = strtoull(&line[6], NULL, 10);
 172                 else if (strncmp(line, "MINOR=", 6) == 0)
 173                         min = strtoull(&line[6], NULL, 10);
 174
 175                 device_add_property_from_string(udev_device, line);
 176         }
 177
 178         udev_device->devnum = makedev(maj, min);
 179
 180         fclose(f);
 181         return 0;
 182 }
 183
 184 static void device_load_info(struct udev_device *device)
 185 {
 186         device_read_uevent_file(device);
 187         device_read_db(device);
 188         device->info_loaded = 1;
 189 }
 190
 191 void device_set_info_loaded(struct udev_device *device)
 192 {
 193         device->info_loaded = 1;
 194 }
 195
 196 struct udev_device *device_init(struct udev *udev)
 197 {
 198         struct udev_device *udev_device;
 199
 200         if (udev == NULL)
 201                 return NULL;
 202
 203         udev_device = malloc(sizeof(struct udev_device));
 204         if (udev_device == NULL)
 205                 return NULL;
 206         memset(udev_device, 0x00, sizeof(struct udev_device));
 207         udev_device->refcount = 1;
 208         udev_device->udev = udev;
 209         list_init(&udev_device->devlink_list);
 210         list_init(&udev_device->properties_list);
 211         list_init(&udev_device->attr_list);
 212         info(udev_device->udev, "udev_device: %p created\n", udev_device);
 213         return udev_device;
 214 }
 215
 216 /**
 217  * udev_device_new_from_syspath:
 218  * @udev: udev library context
 219  * @syspath: sys device path including sys directory
 220  *
 221  * Create new udev device, and fill in information from the sys
 222  * device and the udev database entry. The sypath is the absolute
 223  * path to the device, including the sys mount point.
 224  *
 225  * The initial refcount is 1, and needs to be decremented to
 226  * release the ressources of the udev device.
 227  *
 228  * Returns: a new udev device, or #NULL, if it does not exist
 229  **/
 230 struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
 231 {
 232         size_t len;
 233         const char *subdir;
 234         const char *pos;
 235         char path[UTIL_PATH_SIZE];
 236         struct stat statbuf;
 237         struct udev_device *udev_device;
 238
 239         if (udev == NULL)
 240                 return NULL;
 241         if (syspath == NULL)
 242                 return NULL;
 243
 244         /* path starts in sys */
 245         len = strlen(udev_get_sys_path(udev));
 246         if (strncmp(syspath, udev_get_sys_path(udev), len) != 0) {
 247                 info(udev, "not in sys :%s\n", syspath);
 248                 return NULL;
 249         }
 250
 251         /* path is not a root directory */
 252         subdir = &syspath[len+1];
 253         pos = strrchr(subdir, '/');
 254         if (pos == NULL || pos < &subdir[2]) {
 255                 info(udev, "not a subdir :%s\n", syspath);
 256                 return NULL;
 257         }
 258
 259         /* resolve possible symlink to real path */
 260         util_strlcpy(path, syspath, sizeof(path));
 261         util_resolve_sys_link(udev, path, sizeof(path));
 262
 263         /* path exists in sys */
 264         if (strncmp(&syspath[len], "/devices/", 9) == 0 ||
 265             strncmp(&syspath[len], "/class/", 7) == 0 ||
 266             strncmp(&syspath[len], "/block/", 7) == 0) {
 267                 char file[UTIL_PATH_SIZE];
 268
 269                 /* all "devices" require a "uevent" file */
 270                 util_strlcpy(file, path, sizeof(file));
 271                 util_strlcat(file, "/uevent", sizeof(file));
 272                 if (stat(file, &statbuf) != 0) {
 273                         info(udev, "not a device: %s\n", syspath);
 274                         return NULL;
 275                 }
 276         } else {
 277                 /* everything else just needs to be a directory */
 278                 if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode)) {
 279                         info(udev, "directory not found: %s\n", syspath);
 280                         return NULL;
 281                 }
 282         }
 283
 284         udev_device = device_init(udev);
 285         if (udev_device == NULL)
 286                 return NULL;
 287
 288         device_set_syspath(udev_device, path);
 289         info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
 290
 291         return udev_device;
 292 }
 293
 294 struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 295 {
 296         char path[UTIL_PATH_SIZE];
 297         const char *type_str;
 298         struct udev_enumerate *udev_enumerate;
 299         struct udev_list_entry *list_entry;
 300         struct udev_device *device = NULL;
 301
 302         if (type == 'b')
 303                 type_str = "block";
 304         else if (type == 'c')
 305                 type_str = "char";
 306         else
 307                 return NULL;
 308
 309         /* /sys/dev/{block,char}/<maj>:<min> link */
 310         snprintf(path, sizeof(path), "%s/dev/%s/%u:%u", udev_get_sys_path(udev),
 311                  type_str, major(devnum), minor(devnum));
 312         if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
 313                 return udev_device_new_from_syspath(udev, path);
 314
 315         udev_enumerate = udev_enumerate_new(udev);
 316         if (udev_enumerate == NULL)
 317                 return NULL;
 318
 319         /* fallback to search sys devices for the major/minor */
 320         if (type == 'b')
 321                 udev_enumerate_add_match_subsystem(udev_enumerate, "block");
 322         else if (type == 'c')
 323                 udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
 324         udev_enumerate_scan_devices(udev_enumerate);
 325         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
 326                 struct udev_device *device_loop;
 327
 328                 device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
 329                 if (device_loop != NULL) {
 330                         if (udev_device_get_devnum(device_loop) == devnum) {
 331                                 if (type == 'b' && strcmp(udev_device_get_subsystem(device_loop), "block") != 0)
 332                                         continue;
 333                                 if (type == 'c' && strcmp(udev_device_get_subsystem(device_loop), "block") == 0)
 334                                         continue;
 335                                 device = device_loop;
 336                                 break;
 337                         }
 338                         udev_device_unref(device_loop);
 339                 }
 340         }
 341         udev_enumerate_unref(udev_enumerate);
 342         return device;
 343 }
 344
 345 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 346 {
 347         struct udev_device *udev_device_parent = NULL;
 348         char path[UTIL_PATH_SIZE];
 349         const char *subdir;
 350
 351         /* follow "device" link in deprecated sys layout */
 352         if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 353             strncmp(udev_device->devpath, "/block/", 7) == 0) {
 354                 util_strlcpy(path, udev_device->syspath, sizeof(path));
 355                 util_strlcat(path, "/device", sizeof(path));
 356                 if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0)
 357                         udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 358                 return udev_device_parent;
 359         }
 360
 361         util_strlcpy(path, udev_device->syspath, sizeof(path));
 362         subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
 363         while (1) {
 364                 char *pos;
 365
 366                 pos = strrchr(subdir, '/');
 367                 if (pos == NULL || pos < &subdir[2])
 368                         break;
 369                 pos[0] = '\0';
 370                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 371                 if (udev_device_parent != NULL)
 372                         return udev_device_parent;
 373         }
 374         return NULL;
 375 }
 376
 377 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 378 {
 379         if (udev_device == NULL)
 380                 return NULL;
 381
 382         if (udev_device->parent_device != NULL) {
 383                 info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
 384                 return udev_device->parent_device;
 385         }
 386         udev_device->parent_device = device_new_from_parent(udev_device);
 387         return udev_device->parent_device;
 388 }
 389
 390 /**
 391  * udev_device_get_udev:
 392  * @udev_device: udev device
 393  *
 394  * Retrieve the udev library context the device was created with.
 395  *
 396  * Returns: the udev library context
 397  **/
 398 struct udev *udev_device_get_udev(struct udev_device *udev_device)
 399 {
 400         if (udev_device == NULL)
 401                 return NULL;
 402         return udev_device->udev;
 403 }
 404
 405 /**
 406  * udev_device_ref:
 407  * @udev_device: udev device
 408  *
 409  * Take a reference of a udev device.
 410  *
 411  * Returns: the passed udev device
 412  **/
 413 struct udev_device *udev_device_ref(struct udev_device *udev_device)
 414 {
 415         if (udev_device == NULL)
 416                 return NULL;
 417         udev_device->refcount++;
 418         return udev_device;
 419 }
 420
 421 /**
 422  * udev_device_unref:
 423  * @udev_device: udev device
 424  *
 425  * Drop a reference of a udev device. If the refcount reaches zero,
 426  * the ressources of the device will be released.
 427  *
 428  **/
 429 void udev_device_unref(struct udev_device *udev_device)
 430 {
 431         if (udev_device == NULL)
 432                 return;
 433         udev_device->refcount--;
 434         if (udev_device->refcount > 0)
 435                 return;
 436         if (udev_device->parent_device != NULL)
 437                 udev_device_unref(udev_device->parent_device);
 438         free(udev_device->syspath);
 439         free(udev_device->devnode);
 440         free(udev_device->subsystem);
 441         list_cleanup(udev_device->udev, &udev_device->devlink_list);
 442         list_cleanup(udev_device->udev, &udev_device->properties_list);
 443         free(udev_device->action);
 444         free(udev_device->driver);
 445         free(udev_device->devpath_old);
 446         free(udev_device->physdevpath);
 447         list_cleanup(udev_device->udev, &udev_device->attr_list);
 448         info(udev_device->udev, "udev_device: %p released\n", udev_device);
 449         free(udev_device);
 450 }
 451
 452 /**
 453  * udev_device_get_devpath:
 454  * @udev_device: udev device
 455  *
 456  * Retrieve the kernel devpath value of the udev device. The path
 457  * does not contain the sys mount point, and starts with a '/'.
 458  *
 459  * Returns: the devpath of the udev device
 460  **/
 461 const char *udev_device_get_devpath(struct udev_device *udev_device)
 462 {
 463         if (udev_device == NULL)
 464                 return NULL;
 465         return udev_device->devpath;
 466 }
 467
 468 /**
 469  * udev_device_get_syspath:
 470  * @udev_device: udev device
 471  *
 472  * Retrieve the sys path of the udev device. The path is an
 473  * absolute path and starts with the sys mount point.
 474  *
 475  * Returns: the sys path of the udev device
 476  **/
 477 const char *udev_device_get_syspath(struct udev_device *udev_device)
 478 {
 479         if (udev_device == NULL)
 480                 return NULL;
 481         return udev_device->syspath;
 482 }
 483
 484 const char *udev_device_get_sysname(struct udev_device *udev_device)
 485 {
 486         if (udev_device == NULL)
 487                 return NULL;
 488         return udev_device->sysname;
 489 }
 490
 491 /**
 492  * udev_device_get_devnode:
 493  * @udev_device: udev device
 494  *
 495  * Retrieve the device node file name belonging to the udev device.
 496  * The path is an absolute path, and starts with the device directory.
 497  *
 498  * Returns: the device node file name of the udev device, or #NULL if no device node exists
 499  **/
 500 const char *udev_device_get_devnode(struct udev_device *udev_device)
 501 {
 502         if (udev_device == NULL)
 503                 return NULL;
 504         if (!udev_device->info_loaded)
 505                 device_load_info(udev_device);
 506         return udev_device->devnode;
 507 }
 508
 509 /**
 510  * udev_device_get_subsystem:
 511  * @udev_device: udev device
 512  *
 513  * Retrieve the subsystem string of the udev device. The string does not
 514  * contain any "/".
 515  *
 516  * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
 517  **/
 518 const char *udev_device_get_subsystem(struct udev_device *udev_device)
 519 {
 520         char subsystem[UTIL_NAME_SIZE];
 521
 522         if (udev_device == NULL)
 523                 return NULL;
 524         if (udev_device->subsystem != NULL)
 525                 return udev_device->subsystem;
 526
 527         /* read "subsytem" link */
 528         if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
 529                 udev_device->subsystem = strdup(subsystem);
 530                 return udev_device->subsystem;
 531         }
 532
 533         /* implicit names */
 534         if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
 535                 udev_device->subsystem = strdup("module");
 536                 return udev_device->subsystem;
 537         }
 538         if (strstr(udev_device->devpath, "/drivers/") != NULL) {
 539                 udev_device->subsystem = strdup("drivers");
 540                 return udev_device->subsystem;
 541         }
 542         if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
 543             strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 544             strncmp(udev_device->devpath, "/bus/", 5) == 0) {
 545                 udev_device->subsystem = strdup("subsystem");
 546                 return udev_device->subsystem;
 547         }
 548         return NULL;
 549 }
 550
 551 /**
 552  * udev_device_get_devlinks_list_entry:
 553  * @udev_device: udev device
 554  *
 555  * Retrieve the list of device links pointing to the device file of
 556  * the udev device. The next list entry can be retrieved with
 557  * udev_list_entry_next(), which returns #NULL if no more entries exist.
 558  * The devlink path can be retrieved from the list entry by
 559  * udev_list_entry_get_name(). The path is an absolute path, and starts with
 560  * the device directory.
 561  *
 562  * Returns: the first entry of the device node link list
 563  **/
 564 struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
 565 {
 566         if (udev_device == NULL)
 567                 return NULL;
 568         if (!udev_device->info_loaded)
 569                 device_load_info(udev_device);
 570         return list_get_entry(&udev_device->devlink_list);
 571 }
 572
 573 /**
 574  * udev_device_get_properties_list_entry:
 575  * @udev_device: udev device
 576  *
 577  * Retrieve the list of key/value device properties of the udev
 578  * device. The next list entry can be retrieved with udev_list_entry_next(),
 579  * which returns #NULL if no more entries exist. The property name
 580  * can be retrieved from the list entry by udev_list_get_name(),
 581  * the property value by udev_list_get_value().
 582  *
 583  * Returns: the first entry of the property list
 584  **/
 585 struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
 586 {
 587         if (udev_device == NULL)
 588                 return NULL;
 589         if (!udev_device->info_loaded)
 590                 device_load_info(udev_device);
 591         return list_get_entry(&udev_device->properties_list);
 592 }
 593
 594 const char *udev_device_get_driver(struct udev_device *udev_device)
 595 {
 596         char driver[UTIL_NAME_SIZE];
 597
 598         if (udev_device == NULL)
 599                 return NULL;
 600         if (udev_device->driver != NULL)
 601                 return udev_device->driver;
 602         if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
 603                 return NULL;
 604         udev_device->driver = strdup(driver);
 605         return udev_device->driver;
 606 }
 607
 608 dev_t udev_device_get_devnum(struct udev_device *udev_device)
 609 {
 610         if (udev_device == NULL)
 611                 return makedev(0, 0);
 612         if (!udev_device->info_loaded)
 613                 device_load_info(udev_device);
 614         return udev_device->devnum;
 615 }
 616
 617 const char *udev_device_get_action(struct udev_device *udev_device)
 618 {
 619         if (udev_device == NULL)
 620                 return NULL;
 621         return udev_device->action;
 622 }
 623
 624 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 625 {
 626         if (udev_device == NULL)
 627                 return 0;
 628         return udev_device->seqnum;
 629 }
 630
 631 const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
 632 {
 633         struct udev_list_entry *list_entry;
 634         char path[UTIL_PATH_SIZE];
 635         char value[UTIL_NAME_SIZE];
 636         struct stat statbuf;
 637         int fd;
 638         ssize_t size;
 639         const char *val = NULL;
 640
 641         /* look for possibly already cached result */
 642         udev_list_entry_foreach(list_entry, list_get_entry(&udev_device->attr_list)) {
 643                 if (strcmp(udev_list_entry_get_name(list_entry), attr) == 0) {
 644                         info(udev_device->udev, "got '%s' (%s) from cache\n", attr, udev_list_entry_get_value(list_entry));
 645                         return udev_list_entry_get_value(list_entry);
 646                 }
 647         }
 648
 649         util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
 650         util_strlcat(path, "/", sizeof(path));
 651         util_strlcat(path, attr, sizeof(path));
 652
 653         if (lstat(path, &statbuf) != 0) {
 654                 info(udev_device->udev, "stat '%s' failed: %m\n", path);
 655                 goto out;
 656         }
 657
 658         if (S_ISLNK(statbuf.st_mode)) {
 659                 /* links return the last element of the target path */
 660                 char target[UTIL_NAME_SIZE];
 661                 int len;
 662                 char *pos;
 663
 664                 len = readlink(path, target, sizeof(target));
 665                 if (len > 0) {
 666                         target[len] = '\0';
 667                         pos = strrchr(target, '/');
 668                         if (pos != NULL) {
 669                                 pos = &pos[1];
 670                                 info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
 671                                 list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0, 0);
 672                                 val = udev_list_entry_get_value(list_entry);
 673                         }
 674                 }
 675                 goto out;
 676         }
 677
 678         /* skip directories */
 679         if (S_ISDIR(statbuf.st_mode))
 680                 goto out;
 681
 682         /* skip non-readable files */
 683         if ((statbuf.st_mode & S_IRUSR) == 0)
 684                 goto out;
 685
 686         /* read attribute value */
 687         fd = open(path, O_RDONLY);
 688         if (fd < 0) {
 689                 info(udev_device->udev, "attribute '%s' can not be opened\n", path);
 690                 goto out;
 691         }
 692         size = read(fd, value, sizeof(value));
 693         close(fd);
 694         if (size < 0)
 695                 goto out;
 696         if (size == sizeof(value))
 697                 goto out;
 698
 699         /* got a valid value, store it in cache and return it */
 700         value[size] = '\0';
 701         util_remove_trailing_chars(value, '\n');
 702         info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
 703         list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, value, 0, 0);
 704         val = udev_list_entry_get_value(list_entry);
 705 out:
 706         return val;
 707 }
 708 int device_set_syspath(struct udev_device *udev_device, const char *syspath)
 709 {
 710         const char *pos;
 711
 712         udev_device->syspath = strdup(syspath);
 713         if (udev_device->syspath ==  NULL)
 714                 return -ENOMEM;
 715         udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
 716         pos = strrchr(udev_device->syspath, '/');
 717         if (pos == NULL)
 718                 return -EINVAL;
 719         udev_device->sysname = &pos[1];
 720         return 0;
 721 }
 722
 723 int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
 724 {
 725         udev_device->subsystem = strdup(subsystem);
 726         if (udev_device->subsystem == NULL)
 727                 return -1;
 728         return 0;
 729 }
 730
 731 int device_set_devnode(struct udev_device *udev_device, const char *devnode)
 732 {
 733         udev_device->devnode = strdup(devnode);
 734         if (udev_device->devnode == NULL)
 735                 return -ENOMEM;
 736         return 0;
 737 }
 738
 739 int device_add_devlink(struct udev_device *udev_device, const char *devlink)
 740 {
 741         if (list_entry_add(udev_device->udev, &udev_device->devlink_list, devlink, NULL, 1, 0) == NULL)
 742                 return -ENOMEM;
 743         return 0;
 744 }
 745
 746 int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 747 {
 748         if (list_entry_add(udev_device->udev, &udev_device->properties_list, key, value, 1, 0) == NULL)
 749                 return -ENOMEM;
 750         return 0;
 751 }
 752
 753 int device_add_property_from_string(struct udev_device *udev_device, const char *property)
 754 {
 755         char name[UTIL_PATH_SIZE];
 756         char *val;
 757
 758         strncpy(name, property, sizeof(name));
 759         val = strchr(name, '=');
 760         if (val == NULL)
 761                 return -1;
 762         val[0] = '\0';
 763         val = &val[1];
 764         if (val[0] == '\0')
 765                 val = NULL;
 766         device_add_property(udev_device, name, val);
 767         return 0;
 768 }
 769
 770 int device_set_action(struct udev_device *udev_device, const char *action)
 771 {
 772         udev_device->action = strdup(action);
 773         if (udev_device->action == NULL)
 774                 return -ENOMEM;
 775         return 0;
 776 }
 777
 778 int device_set_driver(struct udev_device *udev_device, const char *driver)
 779 {
 780         udev_device->driver = strdup(driver);
 781         if (udev_device->driver == NULL)
 782                 return -ENOMEM;
 783         return 0;
 784 }
 785
 786 const char *device_get_devpath_old(struct udev_device *udev_device)
 787 {
 788         return udev_device->devpath_old;
 789 }
 790
 791 int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 792 {
 793         udev_device->devpath_old = strdup(devpath_old);
 794         if (udev_device->devpath_old == NULL)
 795                 return -ENOMEM;
 796         return 0;
 797 }
 798
 799 const char *device_get_physdevpath(struct udev_device *udev_device)
 800 {
 801         return udev_device->physdevpath;
 802 }
 803
 804 int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
 805 {
 806         udev_device->physdevpath = strdup(physdevpath);
 807         if (udev_device->physdevpath == NULL)
 808                 return -ENOMEM;
 809         return 0;
 810 }
 811
 812 int device_get_timeout(struct udev_device *udev_device)
 813 {
 814         return udev_device->timeout;
 815 }
 816
 817 int device_set_timeout(struct udev_device *udev_device, int timeout)
 818 {
 819         udev_device->timeout = timeout;
 820         return 0;
 821 }
 822 int device_get_event_timeout(struct udev_device *udev_device)
 823 {
 824         if (!udev_device->info_loaded)
 825                 device_load_info(udev_device);
 826         return udev_device->event_timeout;
 827 }
 828
 829 int device_set_event_timeout(struct udev_device *udev_device, int event_timeout)
 830 {
 831         udev_device->event_timeout = event_timeout;
 832         return 0;
 833 }
 834
 835 int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
 836 {
 837         udev_device->seqnum = seqnum;
 838         return 0;
 839 }
 840
 841 int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
 842 {
 843         udev_device->devnum = devnum;
 844         return 0;
 845 }
 846
 847 int device_get_num_fake_partitions(struct udev_device *udev_device)
 848 {
 849         if (!udev_device->info_loaded)
 850                 device_load_info(udev_device);
 851         return udev_device->num_fake_partitions;
 852 }
 853
 854 int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
 855 {
 856         udev_device->num_fake_partitions = num;
 857         return 0;
 858 }
 859
 860 int device_get_devlink_priority(struct udev_device *udev_device)
 861 {
 862         if (!udev_device->info_loaded)
 863                 device_load_info(udev_device);
 864         return udev_device->devlink_priority;
 865 }
 866
 867 int device_set_devlink_priority(struct udev_device *udev_device, int prio)
 868 {
 869          udev_device->devlink_priority = prio;
 870         return 0;
 871 }
 872
 873 int device_get_ignore_remove(struct udev_device *udev_device)
 874 {
 875         if (!udev_device->info_loaded)
 876                 device_load_info(udev_device);
 877         return udev_device->ignore_remove;
 878 }
 879
 880 int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
 881 {
 882         udev_device->ignore_remove = ignore;
 883         return 0;
 884 }
 885