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_scan_devices(udev_enumerate, "block", NULL);
 322         else if (type == 'c')
 323                 udev_enumerate_scan_devices(udev_enumerate, "!block", NULL);
 324         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
 325                 struct udev_device *device_loop;
 326
 327                 device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
 328                 if (device_loop != NULL) {
 329                         if (udev_device_get_devnum(device_loop) == devnum) {
 330                                 const char *subsystem;
 331
 332                                 subsystem = udev_device_get_subsystem(device_loop);
 333                                 if (type == 'b' && strcmp(subsystem, "block") != 0)
 334                                         continue;
 335                                 if (type == 'c' && strcmp(subsystem, "block") == 0)
 336                                         continue;
 337                                 device = device_loop;
 338                                 break;
 339                         }
 340                         udev_device_unref(device_loop);
 341                 }
 342         }
 343         udev_enumerate_unref(udev_enumerate);
 344         return device;
 345 }
 346
 347 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 348 {
 349         struct udev_device *udev_device_parent = NULL;
 350         char path[UTIL_PATH_SIZE];
 351         const char *subdir;
 352
 353         /* follow "device" link in deprecated sys layout */
 354         if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 355             strncmp(udev_device->devpath, "/block/", 7) == 0) {
 356                 util_strlcpy(path, udev_device->syspath, sizeof(path));
 357                 util_strlcat(path, "/device", sizeof(path));
 358                 if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0)
 359                         udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 360                 return udev_device_parent;
 361         }
 362
 363         util_strlcpy(path, udev_device->syspath, sizeof(path));
 364         subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
 365         while (1) {
 366                 char *pos;
 367
 368                 pos = strrchr(subdir, '/');
 369                 if (pos == NULL || pos < &subdir[2])
 370                         break;
 371                 pos[0] = '\0';
 372                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 373                 if (udev_device_parent != NULL)
 374                         return udev_device_parent;
 375         }
 376         return NULL;
 377 }
 378
 379 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 380 {
 381         if (udev_device == NULL)
 382                 return NULL;
 383
 384         if (udev_device->parent_device != NULL) {
 385                 info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
 386                 return udev_device->parent_device;
 387         }
 388         udev_device->parent_device = device_new_from_parent(udev_device);
 389         return udev_device->parent_device;
 390 }
 391
 392 /**
 393  * udev_device_get_udev:
 394  * @udev_device: udev device
 395  *
 396  * Retrieve the udev library context the device was created with.
 397  *
 398  * Returns: the udev library context
 399  **/
 400 struct udev *udev_device_get_udev(struct udev_device *udev_device)
 401 {
 402         if (udev_device == NULL)
 403                 return NULL;
 404         return udev_device->udev;
 405 }
 406
 407 /**
 408  * udev_device_ref:
 409  * @udev_device: udev device
 410  *
 411  * Take a reference of a udev device.
 412  *
 413  * Returns: the passed udev device
 414  **/
 415 struct udev_device *udev_device_ref(struct udev_device *udev_device)
 416 {
 417         if (udev_device == NULL)
 418                 return NULL;
 419         udev_device->refcount++;
 420         return udev_device;
 421 }
 422
 423 /**
 424  * udev_device_unref:
 425  * @udev_device: udev device
 426  *
 427  * Drop a reference of a udev device. If the refcount reaches zero,
 428  * the ressources of the device will be released.
 429  *
 430  **/
 431 void udev_device_unref(struct udev_device *udev_device)
 432 {
 433         if (udev_device == NULL)
 434                 return;
 435         udev_device->refcount--;
 436         if (udev_device->refcount > 0)
 437                 return;
 438         if (udev_device->parent_device != NULL)
 439                 udev_device_unref(udev_device->parent_device);
 440         free(udev_device->syspath);
 441         free(udev_device->devnode);
 442         free(udev_device->subsystem);
 443         list_cleanup(udev_device->udev, &udev_device->devlink_list);
 444         list_cleanup(udev_device->udev, &udev_device->properties_list);
 445         free(udev_device->action);
 446         free(udev_device->driver);
 447         free(udev_device->devpath_old);
 448         free(udev_device->physdevpath);
 449         list_cleanup(udev_device->udev, &udev_device->attr_list);
 450         info(udev_device->udev, "udev_device: %p released\n", udev_device);
 451         free(udev_device);
 452 }
 453
 454 /**
 455  * udev_device_get_devpath:
 456  * @udev_device: udev device
 457  *
 458  * Retrieve the kernel devpath value of the udev device. The path
 459  * does not contain the sys mount point, and starts with a '/'.
 460  *
 461  * Returns: the devpath of the udev device
 462  **/
 463 const char *udev_device_get_devpath(struct udev_device *udev_device)
 464 {
 465         if (udev_device == NULL)
 466                 return NULL;
 467         return udev_device->devpath;
 468 }
 469
 470 /**
 471  * udev_device_get_syspath:
 472  * @udev_device: udev device
 473  *
 474  * Retrieve the sys path of the udev device. The path is an
 475  * absolute path and starts with the sys mount point.
 476  *
 477  * Returns: the sys path of the udev device
 478  **/
 479 const char *udev_device_get_syspath(struct udev_device *udev_device)
 480 {
 481         if (udev_device == NULL)
 482                 return NULL;
 483         return udev_device->syspath;
 484 }
 485
 486 const char *udev_device_get_sysname(struct udev_device *udev_device)
 487 {
 488         if (udev_device == NULL)
 489                 return NULL;
 490         return udev_device->sysname;
 491 }
 492
 493 /**
 494  * udev_device_get_devnode:
 495  * @udev_device: udev device
 496  *
 497  * Retrieve the device node file name belonging to the udev device.
 498  * The path is an absolute path, and starts with the device directory.
 499  *
 500  * Returns: the device node file name of the udev device, or #NULL if no device node exists
 501  **/
 502 const char *udev_device_get_devnode(struct udev_device *udev_device)
 503 {
 504         if (udev_device == NULL)
 505                 return NULL;
 506         if (!udev_device->info_loaded)
 507                 device_load_info(udev_device);
 508         return udev_device->devnode;
 509 }
 510
 511 /**
 512  * udev_device_get_subsystem:
 513  * @udev_device: udev device
 514  *
 515  * Retrieve the subsystem string of the udev device. The string does not
 516  * contain any "/".
 517  *
 518  * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
 519  **/
 520 const char *udev_device_get_subsystem(struct udev_device *udev_device)
 521 {
 522         char subsystem[UTIL_NAME_SIZE];
 523
 524         if (udev_device == NULL)
 525                 return NULL;
 526         if (udev_device->subsystem != NULL)
 527                 return udev_device->subsystem;
 528
 529         /* read "subsytem" link */
 530         if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
 531                 udev_device->subsystem = strdup(subsystem);
 532                 return udev_device->subsystem;
 533         }
 534
 535         /* implicit names */
 536         if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
 537                 udev_device->subsystem = strdup("module");
 538                 return udev_device->subsystem;
 539         }
 540         if (strstr(udev_device->devpath, "/drivers/") != NULL) {
 541                 udev_device->subsystem = strdup("drivers");
 542                 return udev_device->subsystem;
 543         }
 544         if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
 545             strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 546             strncmp(udev_device->devpath, "/bus/", 5) == 0) {
 547                 udev_device->subsystem = strdup("subsystem");
 548                 return udev_device->subsystem;
 549         }
 550         return NULL;
 551 }
 552
 553 /**
 554  * udev_device_get_devlinks_list_entry:
 555  * @udev_device: udev device
 556  *
 557  * Retrieve the list of device links pointing to the device file of
 558  * the udev device. The next list entry can be retrieved with
 559  * udev_list_entry_next(), which returns #NULL if no more entries exist.
 560  * The devlink path can be retrieved from the list entry by
 561  * udev_list_entry_get_name(). The path is an absolute path, and starts with
 562  * the device directory.
 563  *
 564  * Returns: the first entry of the device node link list
 565  **/
 566 struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
 567 {
 568         if (udev_device == NULL)
 569                 return NULL;
 570         if (!udev_device->info_loaded)
 571                 device_load_info(udev_device);
 572         return list_get_entry(&udev_device->devlink_list);
 573 }
 574
 575 /**
 576  * udev_device_get_properties_list_entry:
 577  * @udev_device: udev device
 578  *
 579  * Retrieve the list of key/value device properties of the udev
 580  * device. The next list entry can be retrieved with udev_list_entry_next(),
 581  * which returns #NULL if no more entries exist. The property name
 582  * can be retrieved from the list entry by udev_list_get_name(),
 583  * the property value by udev_list_get_value().
 584  *
 585  * Returns: the first entry of the property list
 586  **/
 587 struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
 588 {
 589         if (udev_device == NULL)
 590                 return NULL;
 591         if (!udev_device->info_loaded)
 592                 device_load_info(udev_device);
 593         return list_get_entry(&udev_device->properties_list);
 594 }
 595
 596 const char *udev_device_get_driver(struct udev_device *udev_device)
 597 {
 598         char driver[UTIL_NAME_SIZE];
 599
 600         if (udev_device == NULL)
 601                 return NULL;
 602         if (udev_device->driver != NULL)
 603                 return udev_device->driver;
 604         if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
 605                 return NULL;
 606         udev_device->driver = strdup(driver);
 607         return udev_device->driver;
 608 }
 609
 610 dev_t udev_device_get_devnum(struct udev_device *udev_device)
 611 {
 612         if (udev_device == NULL)
 613                 return makedev(0, 0);
 614         if (!udev_device->info_loaded)
 615                 device_load_info(udev_device);
 616         return udev_device->devnum;
 617 }
 618
 619 const char *udev_device_get_action(struct udev_device *udev_device)
 620 {
 621         if (udev_device == NULL)
 622                 return NULL;
 623         return udev_device->action;
 624 }
 625
 626 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 627 {
 628         if (udev_device == NULL)
 629                 return 0;
 630         return udev_device->seqnum;
 631 }
 632
 633 const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
 634 {
 635         struct udev_list_entry *list_entry;
 636         char path[UTIL_PATH_SIZE];
 637         char value[UTIL_NAME_SIZE];
 638         struct stat statbuf;
 639         int fd;
 640         ssize_t size;
 641         const char *val = NULL;
 642
 643         /* look for possibly already cached result */
 644         udev_list_entry_foreach(list_entry, list_get_entry(&udev_device->attr_list)) {
 645                 if (strcmp(udev_list_entry_get_name(list_entry), attr) == 0) {
 646                         info(udev_device->udev, "got '%s' (%s) from cache\n", attr, udev_list_entry_get_value(list_entry));
 647                         return udev_list_entry_get_value(list_entry);
 648                 }
 649         }
 650
 651         util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
 652         util_strlcat(path, "/", sizeof(path));
 653         util_strlcat(path, attr, sizeof(path));
 654
 655         if (lstat(path, &statbuf) != 0) {
 656                 info(udev_device->udev, "stat '%s' failed: %m\n", path);
 657                 goto out;
 658         }
 659
 660         if (S_ISLNK(statbuf.st_mode)) {
 661                 /* links return the last element of the target path */
 662                 char target[UTIL_NAME_SIZE];
 663                 int len;
 664                 char *pos;
 665
 666                 len = readlink(path, target, sizeof(target));
 667                 if (len > 0) {
 668                         target[len] = '\0';
 669                         pos = strrchr(target, '/');
 670                         if (pos != NULL) {
 671                                 pos = &pos[1];
 672                                 info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
 673                                 list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0, 0);
 674                                 val = udev_list_entry_get_value(list_entry);
 675                         }
 676                 }
 677                 goto out;
 678         }
 679
 680         /* skip directories */
 681         if (S_ISDIR(statbuf.st_mode))
 682                 goto out;
 683
 684         /* skip non-readable files */
 685         if ((statbuf.st_mode & S_IRUSR) == 0)
 686                 goto out;
 687
 688         /* read attribute value */
 689         fd = open(path, O_RDONLY);
 690         if (fd < 0) {
 691                 info(udev_device->udev, "attribute '%s' can not be opened\n", path);
 692                 goto out;
 693         }
 694         size = read(fd, value, sizeof(value));
 695         close(fd);
 696         if (size < 0)
 697                 goto out;
 698         if (size == sizeof(value))
 699                 goto out;
 700
 701         /* got a valid value, store it in cache and return it */
 702         value[size] = '\0';
 703         util_remove_trailing_chars(value, '\n');
 704         info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
 705         list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, value, 0, 0);
 706         val = udev_list_entry_get_value(list_entry);
 707 out:
 708         return val;
 709 }
 710 int device_set_syspath(struct udev_device *udev_device, const char *syspath)
 711 {
 712         const char *pos;
 713
 714         udev_device->syspath = strdup(syspath);
 715         if (udev_device->syspath ==  NULL)
 716                 return -ENOMEM;
 717         udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
 718         pos = strrchr(udev_device->syspath, '/');
 719         if (pos == NULL)
 720                 return -EINVAL;
 721         udev_device->sysname = &pos[1];
 722         return 0;
 723 }
 724
 725 int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
 726 {
 727         udev_device->subsystem = strdup(subsystem);
 728         if (udev_device->subsystem == NULL)
 729                 return -1;
 730         return 0;
 731 }
 732
 733 int device_set_devnode(struct udev_device *udev_device, const char *devnode)
 734 {
 735         udev_device->devnode = strdup(devnode);
 736         if (udev_device->devnode == NULL)
 737                 return -ENOMEM;
 738         return 0;
 739 }
 740
 741 int device_add_devlink(struct udev_device *udev_device, const char *devlink)
 742 {
 743         if (list_entry_add(udev_device->udev, &udev_device->devlink_list, devlink, NULL, 1, 0) == NULL)
 744                 return -ENOMEM;
 745         return 0;
 746 }
 747
 748 int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 749 {
 750         if (list_entry_add(udev_device->udev, &udev_device->properties_list, key, value, 1, 0) == NULL)
 751                 return -ENOMEM;
 752         return 0;
 753 }
 754
 755 int device_add_property_from_string(struct udev_device *udev_device, const char *property)
 756 {
 757         char name[UTIL_PATH_SIZE];
 758         char *val;
 759
 760         strncpy(name, property, sizeof(name));
 761         val = strchr(name, '=');
 762         if (val == NULL)
 763                 return -1;
 764         val[0] = '\0';
 765         val = &val[1];
 766         if (val[0] == '\0')
 767                 val = NULL;
 768         device_add_property(udev_device, name, val);
 769         return 0;
 770 }
 771
 772 int device_set_action(struct udev_device *udev_device, const char *action)
 773 {
 774         udev_device->action = strdup(action);
 775         if (udev_device->action == NULL)
 776                 return -ENOMEM;
 777         return 0;
 778 }
 779
 780 int device_set_driver(struct udev_device *udev_device, const char *driver)
 781 {
 782         udev_device->driver = strdup(driver);
 783         if (udev_device->driver == NULL)
 784                 return -ENOMEM;
 785         return 0;
 786 }
 787
 788 const char *device_get_devpath_old(struct udev_device *udev_device)
 789 {
 790         return udev_device->devpath_old;
 791 }
 792
 793 int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 794 {
 795         udev_device->devpath_old = strdup(devpath_old);
 796         if (udev_device->devpath_old == NULL)
 797                 return -ENOMEM;
 798         return 0;
 799 }
 800
 801 const char *device_get_physdevpath(struct udev_device *udev_device)
 802 {
 803         return udev_device->physdevpath;
 804 }
 805
 806 int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
 807 {
 808         udev_device->physdevpath = strdup(physdevpath);
 809         if (udev_device->physdevpath == NULL)
 810                 return -ENOMEM;
 811         return 0;
 812 }
 813
 814 int device_get_timeout(struct udev_device *udev_device)
 815 {
 816         return udev_device->timeout;
 817 }
 818
 819 int device_set_timeout(struct udev_device *udev_device, int timeout)
 820 {
 821         udev_device->timeout = timeout;
 822         return 0;
 823 }
 824 int device_get_event_timeout(struct udev_device *udev_device)
 825 {
 826         if (!udev_device->info_loaded)
 827                 device_load_info(udev_device);
 828         return udev_device->event_timeout;
 829 }
 830
 831 int device_set_event_timeout(struct udev_device *udev_device, int event_timeout)
 832 {
 833         udev_device->event_timeout = event_timeout;
 834         return 0;
 835 }
 836
 837 int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
 838 {
 839         udev_device->seqnum = seqnum;
 840         return 0;
 841 }
 842
 843 int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
 844 {
 845         udev_device->devnum = devnum;
 846         return 0;
 847 }
 848
 849 int device_get_num_fake_partitions(struct udev_device *udev_device)
 850 {
 851         if (!udev_device->info_loaded)
 852                 device_load_info(udev_device);
 853         return udev_device->num_fake_partitions;
 854 }
 855
 856 int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
 857 {
 858         udev_device->num_fake_partitions = num;
 859         return 0;
 860 }
 861
 862 int device_get_devlink_priority(struct udev_device *udev_device)
 863 {
 864         if (!udev_device->info_loaded)
 865                 device_load_info(udev_device);
 866         return udev_device->devlink_priority;
 867 }
 868
 869 int device_set_devlink_priority(struct udev_device *udev_device, int prio)
 870 {
 871          udev_device->devlink_priority = prio;
 872         return 0;
 873 }
 874
 875 int device_get_ignore_remove(struct udev_device *udev_device)
 876 {
 877         if (!udev_device->info_loaded)
 878                 device_load_info(udev_device);
 879         return udev_device->ignore_remove;
 880 }
 881
 882 int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
 883 {
 884         udev_device->ignore_remove = ignore;
 885         return 0;
 886 }
 887