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                 char *next;
  87
  88                 target_len = readlink(filename, target, sizeof(target));
  89                 if (target_len > 0)
  90                         target[target_len] = '\0';
  91                 else {
  92                         info(udev_device->udev, "error reading db link %s: %m\n", filename);
  93                         return -1;
  94                 }
  95
  96                 next = strchr(target, ' ');
  97                 if (next != NULL) {
  98                         next[0] = '\0';
  99                         next = &next[1];
 100                 }
 101                 if (asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
 102                         return -ENOMEM;
 103                 while (next != NULL) {
 104                         char linkname[UTIL_PATH_SIZE];
 105                         const char *lnk;
 106
 107                         lnk = next;
 108                         next = strchr(next, ' ');
 109                         if (next != NULL) {
 110                                 next[0] = '\0';
 111                                 next = &next[1];
 112                         }
 113                         util_strlcpy(linkname, udev_get_dev_path(udev_device->udev), sizeof(linkname));
 114                         util_strlcat(linkname, "/", sizeof(linkname));
 115                         util_strlcat(linkname, lnk, sizeof(linkname));
 116                         device_add_devlink(udev_device, linkname);
 117                 }
 118                 info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
 119                 return 0;
 120         }
 121
 122         f = fopen(filename, "r");
 123         if (f == NULL) {
 124                 info(udev_device->udev, "error reading db file %s: %m\n", filename);
 125                 return -1;
 126         }
 127         while (fgets(line, sizeof(line), f)) {
 128                 ssize_t len;
 129                 const char *val;
 130
 131                 len = strlen(line);
 132                 if (len < 4)
 133                         break;
 134                 line[len-1] = '\0';
 135                 val = &line[2];
 136
 137                 switch(line[0]) {
 138                 case 'N':
 139                         asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), val);
 140                         break;
 141                 case 'S':
 142                         util_strlcpy(filename, udev_get_dev_path(udev_device->udev), sizeof(filename));
 143                         util_strlcat(filename, "/", sizeof(filename));
 144                         util_strlcat(filename, val, sizeof(filename));
 145                         device_add_devlink(udev_device, filename);
 146                         break;
 147                 case 'L':
 148                         device_set_devlink_priority(udev_device, atoi(val));
 149                         break;
 150                 case 'T':
 151                         device_set_event_timeout(udev_device, atoi(val));
 152                         break;
 153                 case 'A':
 154                         device_set_num_fake_partitions(udev_device, atoi(val));
 155                         break;
 156                 case 'R':
 157                         device_set_ignore_remove(udev_device, atoi(val));
 158                         break;
 159                 case 'E':
 160                         device_add_property_from_string(udev_device, val);
 161                         break;
 162                 }
 163         }
 164         fclose(f);
 165
 166         info(udev_device->udev, "device %p filled with db file data\n", udev_device);
 167         return 0;
 168 }
 169
 170 static int device_read_uevent_file(struct udev_device *udev_device)
 171 {
 172         char filename[UTIL_PATH_SIZE];
 173         FILE *f;
 174         char line[UTIL_LINE_SIZE];
 175         int maj = 0;
 176         int min = 0;
 177
 178         util_strlcpy(filename, udev_device->syspath, sizeof(filename));
 179         util_strlcat(filename, "/uevent", sizeof(filename));
 180         f = fopen(filename, "r");
 181         if (f == NULL)
 182                 return -1;
 183
 184         while (fgets(line, sizeof(line), f)) {
 185                 char *pos;
 186
 187                 pos = strchr(line, '\n');
 188                 if (pos == NULL)
 189                         continue;
 190                 pos[0] = '\0';
 191
 192                 if (strncmp(line, "MAJOR=", 6) == 0)
 193                         maj = strtoull(&line[6], NULL, 10);
 194                 else if (strncmp(line, "MINOR=", 6) == 0)
 195                         min = strtoull(&line[6], NULL, 10);
 196
 197                 device_add_property_from_string(udev_device, line);
 198         }
 199
 200         udev_device->devnum = makedev(maj, min);
 201
 202         fclose(f);
 203         return 0;
 204 }
 205
 206 static void device_load_info(struct udev_device *device)
 207 {
 208         device_read_uevent_file(device);
 209         device_read_db(device);
 210         device->info_loaded = 1;
 211 }
 212
 213 void device_set_info_loaded(struct udev_device *device)
 214 {
 215         device->info_loaded = 1;
 216 }
 217
 218 struct udev_device *device_new(struct udev *udev)
 219 {
 220         struct udev_device *udev_device;
 221
 222         if (udev == NULL)
 223                 return NULL;
 224
 225         udev_device = malloc(sizeof(struct udev_device));
 226         if (udev_device == NULL)
 227                 return NULL;
 228         memset(udev_device, 0x00, sizeof(struct udev_device));
 229         udev_device->refcount = 1;
 230         udev_device->udev = udev;
 231         list_init(&udev_device->devlink_list);
 232         list_init(&udev_device->properties_list);
 233         list_init(&udev_device->attr_list);
 234         info(udev_device->udev, "udev_device: %p created\n", udev_device);
 235         return udev_device;
 236 }
 237
 238 /**
 239  * udev_device_new_from_syspath:
 240  * @udev: udev library context
 241  * @syspath: sys device path including sys directory
 242  *
 243  * Create new udev device, and fill in information from the sys
 244  * device and the udev database entry. The sypath is the absolute
 245  * path to the device, including the sys mount point.
 246  *
 247  * The initial refcount is 1, and needs to be decremented to
 248  * release the ressources of the udev device.
 249  *
 250  * Returns: a new udev device, or #NULL, if it does not exist
 251  **/
 252 struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
 253 {
 254         size_t len;
 255         const char *subdir;
 256         char path[UTIL_PATH_SIZE];
 257         char *pos;
 258         struct stat statbuf;
 259         struct udev_device *udev_device;
 260
 261         if (udev == NULL)
 262                 return NULL;
 263         if (syspath == NULL)
 264                 return NULL;
 265
 266         /* path starts in sys */
 267         len = strlen(udev_get_sys_path(udev));
 268         if (strncmp(syspath, udev_get_sys_path(udev), len) != 0) {
 269                 info(udev, "not in sys :%s\n", syspath);
 270                 return NULL;
 271         }
 272
 273         /* path is not a root directory */
 274         subdir = &syspath[len+1];
 275         pos = strrchr(subdir, '/');
 276         if (pos == NULL || pos < &subdir[2]) {
 277                 info(udev, "not a subdir :%s\n", syspath);
 278                 return NULL;
 279         }
 280
 281         /* resolve possible symlink to real path */
 282         util_strlcpy(path, syspath, sizeof(path));
 283         util_resolve_sys_link(udev, path, sizeof(path));
 284
 285         /* try to resolve the silly block layout if needed */
 286         if (strncmp(&path[len], "/block/", 7) == 0) {
 287                 char block[UTIL_PATH_SIZE];
 288                 char part[UTIL_PATH_SIZE];
 289
 290                 util_strlcpy(block, path, sizeof(block));
 291                 pos = strrchr(block, '/');
 292                 if (pos == NULL)
 293                         return NULL;
 294                 util_strlcpy(part, pos, sizeof(part));
 295                 pos[0] = '\0';
 296                 if (util_resolve_sys_link(udev, block, sizeof(block)) == 0) {
 297                         util_strlcpy(path, block, sizeof(path));
 298                         util_strlcat(path, part, sizeof(path));
 299                 }
 300         }
 301
 302         /* path exists in sys */
 303         if (strncmp(&syspath[len], "/devices/", 9) == 0 ||
 304             strncmp(&syspath[len], "/class/", 7) == 0 ||
 305             strncmp(&syspath[len], "/block/", 7) == 0) {
 306                 char file[UTIL_PATH_SIZE];
 307
 308                 /* all "devices" require a "uevent" file */
 309                 util_strlcpy(file, path, sizeof(file));
 310                 util_strlcat(file, "/uevent", sizeof(file));
 311                 if (stat(file, &statbuf) != 0) {
 312                         info(udev, "not a device: %s\n", syspath);
 313                         return NULL;
 314                 }
 315         } else {
 316                 /* everything else just needs to be a directory */
 317                 if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode)) {
 318                         info(udev, "directory not found: %s\n", syspath);
 319                         return NULL;
 320                 }
 321         }
 322
 323         udev_device = device_new(udev);
 324         if (udev_device == NULL)
 325                 return NULL;
 326
 327         device_set_syspath(udev_device, path);
 328         info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
 329
 330         return udev_device;
 331 }
 332
 333 struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 334 {
 335         char path[UTIL_PATH_SIZE];
 336         const char *type_str;
 337         struct udev_enumerate *udev_enumerate;
 338         struct udev_list_entry *list_entry;
 339         struct udev_device *device = NULL;
 340
 341         if (type == 'b')
 342                 type_str = "block";
 343         else if (type == 'c')
 344                 type_str = "char";
 345         else
 346                 return NULL;
 347
 348         /* /sys/dev/{block,char}/<maj>:<min> link */
 349         snprintf(path, sizeof(path), "%s/dev/%s/%u:%u", udev_get_sys_path(udev),
 350                  type_str, major(devnum), minor(devnum));
 351         if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
 352                 return udev_device_new_from_syspath(udev, path);
 353
 354         udev_enumerate = udev_enumerate_new(udev);
 355         if (udev_enumerate == NULL)
 356                 return NULL;
 357
 358         /* fallback to search sys devices for the major/minor */
 359         if (type == 'b')
 360                 udev_enumerate_add_match_subsystem(udev_enumerate, "block");
 361         else if (type == 'c')
 362                 udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
 363         udev_enumerate_scan_devices(udev_enumerate);
 364         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
 365                 struct udev_device *device_loop;
 366
 367                 device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
 368                 if (device_loop != NULL) {
 369                         if (udev_device_get_devnum(device_loop) == devnum) {
 370                                 if (type == 'b' && strcmp(udev_device_get_subsystem(device_loop), "block") != 0)
 371                                         continue;
 372                                 if (type == 'c' && strcmp(udev_device_get_subsystem(device_loop), "block") == 0)
 373                                         continue;
 374                                 device = device_loop;
 375                                 break;
 376                         }
 377                         udev_device_unref(device_loop);
 378                 }
 379         }
 380         udev_enumerate_unref(udev_enumerate);
 381         return device;
 382 }
 383
 384 struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 385 {
 386         size_t sys_path_len;
 387         char path_full[UTIL_PATH_SIZE];
 388         char *path;
 389         struct stat statbuf;
 390
 391         sys_path_len = util_strlcpy(path_full, udev_get_sys_path(udev), sizeof(path_full));
 392         path = &path_full[sys_path_len];
 393
 394         if (strcmp(subsystem, "subsystem") == 0) {
 395                 util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
 396                 util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 397                 if (stat(path_full, &statbuf) == 0)
 398                         goto found;
 399
 400                 util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
 401                 util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 402                 if (stat(path_full, &statbuf) == 0)
 403                         goto found;
 404
 405                 util_strlcpy(path, "/class/", sizeof(path_full) - sys_path_len);
 406                 util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 407                 if (stat(path_full, &statbuf) == 0)
 408                         goto found;
 409                 goto out;
 410         }
 411
 412         if (strcmp(subsystem, "module") == 0) {
 413                 util_strlcpy(path, "/module/", sizeof(path_full) - sys_path_len);
 414                 util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 415                 if (stat(path_full, &statbuf) == 0)
 416                         goto found;
 417                 goto out;
 418         }
 419
 420         if (strcmp(subsystem, "drivers") == 0) {
 421                 char subsys[UTIL_NAME_SIZE];
 422                 char *driver;
 423
 424                 util_strlcpy(subsys, sysname, sizeof(subsys));
 425                 driver = strchr(subsys, ':');
 426                 if (driver != NULL) {
 427                         driver[0] = '\0';
 428                         driver = &driver[1];
 429                         util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
 430                         util_strlcat(path, subsys, sizeof(path_full) - sys_path_len);
 431                         util_strlcat(path, "/drivers/", sizeof(path_full) - sys_path_len);
 432                         util_strlcat(path, driver, sizeof(path_full) - sys_path_len);
 433                         if (stat(path_full, &statbuf) == 0)
 434                                 goto found;
 435
 436                         util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
 437                         util_strlcat(path, subsys, sizeof(path_full) - sys_path_len);
 438                         util_strlcat(path, "/drivers/", sizeof(path_full) - sys_path_len);
 439                         util_strlcat(path, driver, sizeof(path_full) - sys_path_len);
 440                         if (stat(path_full, &statbuf) == 0)
 441                                 goto found;
 442                 }
 443                 goto out;
 444         }
 445
 446         util_strlcpy(path, "/subsystem/", sizeof(path_full) - sys_path_len);
 447         util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
 448         util_strlcat(path, "/devices/", sizeof(path_full) - sys_path_len);
 449         util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 450         if (stat(path_full, &statbuf) == 0)
 451                 goto found;
 452
 453         util_strlcpy(path, "/bus/", sizeof(path_full) - sys_path_len);
 454         util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
 455         util_strlcat(path, "/devices/", sizeof(path_full) - sys_path_len);
 456         util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 457         if (stat(path_full, &statbuf) == 0)
 458                 goto found;
 459
 460         util_strlcpy(path, "/class/", sizeof(path_full) - sys_path_len);
 461         util_strlcat(path, subsystem, sizeof(path_full) - sys_path_len);
 462         util_strlcat(path, "/", sizeof(path_full) - sys_path_len);
 463         util_strlcat(path, sysname, sizeof(path_full) - sys_path_len);
 464         if (stat(path_full, &statbuf) == 0)
 465                 goto found;
 466 out:
 467         return NULL;
 468 found:
 469         return udev_device_new_from_syspath(udev, path_full);
 470 }
 471
 472 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 473 {
 474         struct udev_device *udev_device_parent = NULL;
 475         char path[UTIL_PATH_SIZE];
 476         const char *subdir;
 477
 478         /* follow "device" link in deprecated sys layout */
 479         if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 480             strncmp(udev_device->devpath, "/block/", 7) == 0) {
 481                 util_strlcpy(path, udev_device->syspath, sizeof(path));
 482                 util_strlcat(path, "/device", sizeof(path));
 483                 if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0)
 484                         udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 485                 return udev_device_parent;
 486         }
 487
 488         util_strlcpy(path, udev_device->syspath, sizeof(path));
 489         subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
 490         while (1) {
 491                 char *pos;
 492
 493                 pos = strrchr(subdir, '/');
 494                 if (pos == NULL || pos < &subdir[2])
 495                         break;
 496                 pos[0] = '\0';
 497                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 498                 if (udev_device_parent != NULL)
 499                         return udev_device_parent;
 500         }
 501         return NULL;
 502 }
 503
 504 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 505 {
 506         if (udev_device == NULL)
 507                 return NULL;
 508
 509         if (udev_device->parent_device != NULL) {
 510                 info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
 511                 return udev_device->parent_device;
 512         }
 513         udev_device->parent_device = device_new_from_parent(udev_device);
 514         return udev_device->parent_device;
 515 }
 516
 517 struct udev_device *udev_device_get_parent_with_subsystem(struct udev_device *udev_device, const char *subsystem)
 518 {
 519         struct udev_device *parent;
 520
 521         parent = udev_device_get_parent(udev_device);
 522         while (parent != NULL) {
 523                 const char *parent_subsystem;
 524
 525                 parent_subsystem = udev_device_get_subsystem(parent);
 526                 if (parent_subsystem != NULL && strcmp(parent_subsystem, subsystem) == 0)
 527                         break;
 528                 parent = udev_device_get_parent(parent);
 529         }
 530         return parent;
 531 }
 532
 533 /**
 534  * udev_device_get_udev:
 535  * @udev_device: udev device
 536  *
 537  * Retrieve the udev library context the device was created with.
 538  *
 539  * Returns: the udev library context
 540  **/
 541 struct udev *udev_device_get_udev(struct udev_device *udev_device)
 542 {
 543         if (udev_device == NULL)
 544                 return NULL;
 545         return udev_device->udev;
 546 }
 547
 548 /**
 549  * udev_device_ref:
 550  * @udev_device: udev device
 551  *
 552  * Take a reference of a udev device.
 553  *
 554  * Returns: the passed udev device
 555  **/
 556 struct udev_device *udev_device_ref(struct udev_device *udev_device)
 557 {
 558         if (udev_device == NULL)
 559                 return NULL;
 560         udev_device->refcount++;
 561         return udev_device;
 562 }
 563
 564 /**
 565  * udev_device_unref:
 566  * @udev_device: udev device
 567  *
 568  * Drop a reference of a udev device. If the refcount reaches zero,
 569  * the ressources of the device will be released.
 570  *
 571  **/
 572 void udev_device_unref(struct udev_device *udev_device)
 573 {
 574         if (udev_device == NULL)
 575                 return;
 576         udev_device->refcount--;
 577         if (udev_device->refcount > 0)
 578                 return;
 579         if (udev_device->parent_device != NULL)
 580                 udev_device_unref(udev_device->parent_device);
 581         free(udev_device->syspath);
 582         free(udev_device->devnode);
 583         free(udev_device->subsystem);
 584         list_cleanup(udev_device->udev, &udev_device->devlink_list);
 585         list_cleanup(udev_device->udev, &udev_device->properties_list);
 586         free(udev_device->action);
 587         free(udev_device->driver);
 588         free(udev_device->devpath_old);
 589         free(udev_device->physdevpath);
 590         list_cleanup(udev_device->udev, &udev_device->attr_list);
 591         info(udev_device->udev, "udev_device: %p released\n", udev_device);
 592         free(udev_device);
 593 }
 594
 595 /**
 596  * udev_device_get_devpath:
 597  * @udev_device: udev device
 598  *
 599  * Retrieve the kernel devpath value of the udev device. The path
 600  * does not contain the sys mount point, and starts with a '/'.
 601  *
 602  * Returns: the devpath of the udev device
 603  **/
 604 const char *udev_device_get_devpath(struct udev_device *udev_device)
 605 {
 606         if (udev_device == NULL)
 607                 return NULL;
 608         return udev_device->devpath;
 609 }
 610
 611 /**
 612  * udev_device_get_syspath:
 613  * @udev_device: udev device
 614  *
 615  * Retrieve the sys path of the udev device. The path is an
 616  * absolute path and starts with the sys mount point.
 617  *
 618  * Returns: the sys path of the udev device
 619  **/
 620 const char *udev_device_get_syspath(struct udev_device *udev_device)
 621 {
 622         if (udev_device == NULL)
 623                 return NULL;
 624         return udev_device->syspath;
 625 }
 626
 627 const char *udev_device_get_sysname(struct udev_device *udev_device)
 628 {
 629         if (udev_device == NULL)
 630                 return NULL;
 631         return udev_device->sysname;
 632 }
 633
 634 /**
 635  * udev_device_get_devnode:
 636  * @udev_device: udev device
 637  *
 638  * Retrieve the device node file name belonging to the udev device.
 639  * The path is an absolute path, and starts with the device directory.
 640  *
 641  * Returns: the device node file name of the udev device, or #NULL if no device node exists
 642  **/
 643 const char *udev_device_get_devnode(struct udev_device *udev_device)
 644 {
 645         if (udev_device == NULL)
 646                 return NULL;
 647         if (!udev_device->info_loaded)
 648                 device_load_info(udev_device);
 649         return udev_device->devnode;
 650 }
 651
 652 /**
 653  * udev_device_get_subsystem:
 654  * @udev_device: udev device
 655  *
 656  * Retrieve the subsystem string of the udev device. The string does not
 657  * contain any "/".
 658  *
 659  * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
 660  **/
 661 const char *udev_device_get_subsystem(struct udev_device *udev_device)
 662 {
 663         char subsystem[UTIL_NAME_SIZE];
 664
 665         if (udev_device == NULL)
 666                 return NULL;
 667         if (udev_device->subsystem != NULL)
 668                 return udev_device->subsystem;
 669
 670         /* read "subsytem" link */
 671         if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
 672                 udev_device->subsystem = strdup(subsystem);
 673                 return udev_device->subsystem;
 674         }
 675
 676         /* implicit names */
 677         if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
 678                 udev_device->subsystem = strdup("module");
 679                 return udev_device->subsystem;
 680         }
 681         if (strstr(udev_device->devpath, "/drivers/") != NULL) {
 682                 udev_device->subsystem = strdup("drivers");
 683                 return udev_device->subsystem;
 684         }
 685         if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
 686             strncmp(udev_device->devpath, "/class/", 7) == 0 ||
 687             strncmp(udev_device->devpath, "/bus/", 5) == 0) {
 688                 udev_device->subsystem = strdup("subsystem");
 689                 return udev_device->subsystem;
 690         }
 691         return NULL;
 692 }
 693
 694 /**
 695  * udev_device_get_devlinks_list_entry:
 696  * @udev_device: udev device
 697  *
 698  * Retrieve the list of device links pointing to the device file of
 699  * the udev device. The next list entry can be retrieved with
 700  * udev_list_entry_next(), which returns #NULL if no more entries exist.
 701  * The devlink path can be retrieved from the list entry by
 702  * udev_list_entry_get_name(). The path is an absolute path, and starts with
 703  * the device directory.
 704  *
 705  * Returns: the first entry of the device node link list
 706  **/
 707 struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
 708 {
 709         if (udev_device == NULL)
 710                 return NULL;
 711         if (!udev_device->info_loaded)
 712                 device_load_info(udev_device);
 713         return list_get_entry(&udev_device->devlink_list);
 714 }
 715
 716 /**
 717  * udev_device_get_properties_list_entry:
 718  * @udev_device: udev device
 719  *
 720  * Retrieve the list of key/value device properties of the udev
 721  * device. The next list entry can be retrieved with udev_list_entry_next(),
 722  * which returns #NULL if no more entries exist. The property name
 723  * can be retrieved from the list entry by udev_list_get_name(),
 724  * the property value by udev_list_get_value().
 725  *
 726  * Returns: the first entry of the property list
 727  **/
 728 struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
 729 {
 730         if (udev_device == NULL)
 731                 return NULL;
 732         if (!udev_device->info_loaded)
 733                 device_load_info(udev_device);
 734         return list_get_entry(&udev_device->properties_list);
 735 }
 736
 737 const char *udev_device_get_driver(struct udev_device *udev_device)
 738 {
 739         char driver[UTIL_NAME_SIZE];
 740
 741         if (udev_device == NULL)
 742                 return NULL;
 743         if (udev_device->driver != NULL)
 744                 return udev_device->driver;
 745         if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
 746                 return NULL;
 747         udev_device->driver = strdup(driver);
 748         return udev_device->driver;
 749 }
 750
 751 dev_t udev_device_get_devnum(struct udev_device *udev_device)
 752 {
 753         if (udev_device == NULL)
 754                 return makedev(0, 0);
 755         if (!udev_device->info_loaded)
 756                 device_load_info(udev_device);
 757         return udev_device->devnum;
 758 }
 759
 760 const char *udev_device_get_action(struct udev_device *udev_device)
 761 {
 762         if (udev_device == NULL)
 763                 return NULL;
 764         return udev_device->action;
 765 }
 766
 767 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 768 {
 769         if (udev_device == NULL)
 770                 return 0;
 771         return udev_device->seqnum;
 772 }
 773
 774 const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
 775 {
 776         struct udev_list_entry *list_entry;
 777         char path[UTIL_PATH_SIZE];
 778         char value[UTIL_NAME_SIZE];
 779         struct stat statbuf;
 780         int fd;
 781         ssize_t size;
 782         const char *val = NULL;
 783
 784         /* look for possibly already cached result */
 785         udev_list_entry_foreach(list_entry, list_get_entry(&udev_device->attr_list)) {
 786                 if (strcmp(udev_list_entry_get_name(list_entry), attr) == 0) {
 787                         info(udev_device->udev, "got '%s' (%s) from cache\n", attr, udev_list_entry_get_value(list_entry));
 788                         return udev_list_entry_get_value(list_entry);
 789                 }
 790         }
 791
 792         util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
 793         util_strlcat(path, "/", sizeof(path));
 794         util_strlcat(path, attr, sizeof(path));
 795
 796         if (lstat(path, &statbuf) != 0) {
 797                 info(udev_device->udev, "stat '%s' failed: %m\n", path);
 798                 goto out;
 799         }
 800
 801         if (S_ISLNK(statbuf.st_mode)) {
 802                 /* links return the last element of the target path */
 803                 char target[UTIL_NAME_SIZE];
 804                 int len;
 805                 char *pos;
 806
 807                 len = readlink(path, target, sizeof(target));
 808                 if (len > 0) {
 809                         target[len] = '\0';
 810                         pos = strrchr(target, '/');
 811                         if (pos != NULL) {
 812                                 pos = &pos[1];
 813                                 info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
 814                                 list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0, 0);
 815                                 val = udev_list_entry_get_value(list_entry);
 816                         }
 817                 }
 818                 goto out;
 819         }
 820
 821         /* skip directories */
 822         if (S_ISDIR(statbuf.st_mode))
 823                 goto out;
 824
 825         /* skip non-readable files */
 826         if ((statbuf.st_mode & S_IRUSR) == 0)
 827                 goto out;
 828
 829         /* read attribute value */
 830         fd = open(path, O_RDONLY);
 831         if (fd < 0) {
 832                 info(udev_device->udev, "attribute '%s' can not be opened\n", path);
 833                 goto out;
 834         }
 835         size = read(fd, value, sizeof(value));
 836         close(fd);
 837         if (size < 0)
 838                 goto out;
 839         if (size == sizeof(value))
 840                 goto out;
 841
 842         /* got a valid value, store it in cache and return it */
 843         value[size] = '\0';
 844         util_remove_trailing_chars(value, '\n');
 845         info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
 846         list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, value, 0, 0);
 847         val = udev_list_entry_get_value(list_entry);
 848 out:
 849         return val;
 850 }
 851 int device_set_syspath(struct udev_device *udev_device, const char *syspath)
 852 {
 853         const char *pos;
 854
 855         udev_device->syspath = strdup(syspath);
 856         if (udev_device->syspath ==  NULL)
 857                 return -ENOMEM;
 858         udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
 859         pos = strrchr(udev_device->syspath, '/');
 860         if (pos == NULL)
 861                 return -EINVAL;
 862         udev_device->sysname = &pos[1];
 863         return 0;
 864 }
 865
 866 int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
 867 {
 868         udev_device->subsystem = strdup(subsystem);
 869         if (udev_device->subsystem == NULL)
 870                 return -1;
 871         return 0;
 872 }
 873
 874 int device_set_devnode(struct udev_device *udev_device, const char *devnode)
 875 {
 876         udev_device->devnode = strdup(devnode);
 877         if (udev_device->devnode == NULL)
 878                 return -ENOMEM;
 879         return 0;
 880 }
 881
 882 int device_add_devlink(struct udev_device *udev_device, const char *devlink)
 883 {
 884         if (list_entry_add(udev_device->udev, &udev_device->devlink_list, devlink, NULL, 1, 0) == NULL)
 885                 return -ENOMEM;
 886         return 0;
 887 }
 888
 889 int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 890 {
 891         if (list_entry_add(udev_device->udev, &udev_device->properties_list, key, value, 1, 0) == NULL)
 892                 return -ENOMEM;
 893         return 0;
 894 }
 895
 896 int device_add_property_from_string(struct udev_device *udev_device, const char *property)
 897 {
 898         char name[UTIL_PATH_SIZE];
 899         char *val;
 900
 901         strncpy(name, property, sizeof(name));
 902         val = strchr(name, '=');
 903         if (val == NULL)
 904                 return -1;
 905         val[0] = '\0';
 906         val = &val[1];
 907         if (val[0] == '\0')
 908                 val = NULL;
 909         device_add_property(udev_device, name, val);
 910         return 0;
 911 }
 912
 913 int device_set_action(struct udev_device *udev_device, const char *action)
 914 {
 915         udev_device->action = strdup(action);
 916         if (udev_device->action == NULL)
 917                 return -ENOMEM;
 918         return 0;
 919 }
 920
 921 int device_set_driver(struct udev_device *udev_device, const char *driver)
 922 {
 923         udev_device->driver = strdup(driver);
 924         if (udev_device->driver == NULL)
 925                 return -ENOMEM;
 926         return 0;
 927 }
 928
 929 const char *device_get_devpath_old(struct udev_device *udev_device)
 930 {
 931         return udev_device->devpath_old;
 932 }
 933
 934 int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 935 {
 936         udev_device->devpath_old = strdup(devpath_old);
 937         if (udev_device->devpath_old == NULL)
 938                 return -ENOMEM;
 939         return 0;
 940 }
 941
 942 const char *device_get_physdevpath(struct udev_device *udev_device)
 943 {
 944         return udev_device->physdevpath;
 945 }
 946
 947 int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
 948 {
 949         udev_device->physdevpath = strdup(physdevpath);
 950         if (udev_device->physdevpath == NULL)
 951                 return -ENOMEM;
 952         return 0;
 953 }
 954
 955 int device_get_timeout(struct udev_device *udev_device)
 956 {
 957         return udev_device->timeout;
 958 }
 959
 960 int device_set_timeout(struct udev_device *udev_device, int timeout)
 961 {
 962         udev_device->timeout = timeout;
 963         return 0;
 964 }
 965 int device_get_event_timeout(struct udev_device *udev_device)
 966 {
 967         if (!udev_device->info_loaded)
 968                 device_load_info(udev_device);
 969         return udev_device->event_timeout;
 970 }
 971
 972 int device_set_event_timeout(struct udev_device *udev_device, int event_timeout)
 973 {
 974         udev_device->event_timeout = event_timeout;
 975         return 0;
 976 }
 977
 978 int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
 979 {
 980         udev_device->seqnum = seqnum;
 981         return 0;
 982 }
 983
 984 int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
 985 {
 986         udev_device->devnum = devnum;
 987         return 0;
 988 }
 989
 990 int device_get_num_fake_partitions(struct udev_device *udev_device)
 991 {
 992         if (!udev_device->info_loaded)
 993                 device_load_info(udev_device);
 994         return udev_device->num_fake_partitions;
 995 }
 996
 997 int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
 998 {
 999         udev_device->num_fake_partitions = num;
1000         return 0;
1001 }
1002
1003 int device_get_devlink_priority(struct udev_device *udev_device)
1004 {
1005         if (!udev_device->info_loaded)
1006                 device_load_info(udev_device);
1007         return udev_device->devlink_priority;
1008 }
1009
1010 int device_set_devlink_priority(struct udev_device *udev_device, int prio)
1011 {
1012          udev_device->devlink_priority = prio;
1013         return 0;
1014 }
1015
1016 int device_get_ignore_remove(struct udev_device *udev_device)
1017 {
1018         if (!udev_device->info_loaded)
1019                 device_load_info(udev_device);
1020         return udev_device->ignore_remove;
1021 }
1022
1023 int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
1024 {
1025         udev_device->ignore_remove = ignore;
1026         return 0;
1027 }
1028