src/libudev/libudev-device.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
   6   Copyright 2015 Tom Gundersen <teg@jklm.no>
   7 ***/
   8
   9 #include <ctype.h>
  10 #include <dirent.h>
  11 #include <errno.h>
  12 #include <fcntl.h>
  13 #include <linux/sockios.h>
  14 #include <net/if.h>
  15 #include <stdbool.h>
  16 #include <stddef.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <sys/ioctl.h>
  21 #include <sys/socket.h>
  22 #include <sys/stat.h>
  23 #include <unistd.h>
  24
  25 #include "libudev.h"
  26 #include "sd-device.h"
  27
  28 #include "alloc-util.h"
  29 #include "device-private.h"
  30 #include "device-util.h"
  31 #include "libudev-device-internal.h"
  32 #include "libudev-private.h"
  33 #include "parse-util.h"
  34
  35 /**
  36  * SECTION:libudev-device
  37  * @short_description: kernel sys devices
  38  *
  39  * Representation of kernel sys devices. Devices are uniquely identified
  40  * by their syspath, every device has exactly one path in the kernel sys
  41  * filesystem. Devices usually belong to a kernel subsystem, and have
  42  * a unique name inside that subsystem.
  43  */
  44
  45 /**
  46  * udev_device_get_seqnum:
  47  * @udev_device: udev device
  48  *
  49  * This is only valid if the device was received through a monitor. Devices read from
  50  * sys do not have a sequence number.
  51  *
  52  * Returns: the kernel event sequence number, or 0 if there is no sequence number available.
  53  **/
  54 _public_ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
  55 {
  56         const char *seqnum;
  57         unsigned long long ret;
  58         int r;
  59
  60         assert_return_errno(udev_device, 0, EINVAL);
  61
  62         r = sd_device_get_property_value(udev_device->device, "SEQNUM", &seqnum);
  63         if (r == -ENOENT)
  64                 return 0;
  65         else if (r < 0) {
  66                 errno = -r;
  67                 return 0;
  68         }
  69
  70         r = safe_atollu(seqnum, &ret);
  71         if (r < 0) {
  72                 errno = -r;
  73                 return 0;
  74         }
  75
  76         return ret;
  77 }
  78
  79 /**
  80  * udev_device_get_devnum:
  81  * @udev_device: udev device
  82  *
  83  * Get the device major/minor number.
  84  *
  85  * Returns: the dev_t number.
  86  **/
  87 _public_ dev_t udev_device_get_devnum(struct udev_device *udev_device)
  88 {
  89         dev_t devnum;
  90         int r;
  91
  92         assert_return_errno(udev_device, makedev(0, 0), EINVAL);
  93
  94         r = sd_device_get_devnum(udev_device->device, &devnum);
  95         if (r < 0) {
  96                 errno = -r;
  97                 return makedev(0, 0);
  98         }
  99
 100         return devnum;
 101 }
 102
 103 /**
 104  * udev_device_get_driver:
 105  * @udev_device: udev device
 106  *
 107  * Get the kernel driver name.
 108  *
 109  * Returns: the driver name string, or #NULL if there is no driver attached.
 110  **/
 111 _public_ const char *udev_device_get_driver(struct udev_device *udev_device)
 112 {
 113         const char *driver;
 114         int r;
 115
 116         assert_return_errno(udev_device, NULL, EINVAL);
 117
 118         r = sd_device_get_driver(udev_device->device, &driver);
 119         if (r < 0) {
 120                 errno = -r;
 121                 return NULL;
 122         }
 123
 124         return driver;
 125 }
 126
 127 /**
 128  * udev_device_get_devtype:
 129  * @udev_device: udev device
 130  *
 131  * Retrieve the devtype string of the udev device.
 132  *
 133  * Returns: the devtype name of the udev device, or #NULL if it cannot be determined
 134  **/
 135 _public_ const char *udev_device_get_devtype(struct udev_device *udev_device)
 136 {
 137         const char *devtype;
 138         int r;
 139
 140         assert_return_errno(udev_device, NULL, EINVAL);
 141
 142         r = sd_device_get_devtype(udev_device->device, &devtype);
 143         if (r < 0) {
 144                 errno = -r;
 145                 return NULL;
 146         }
 147
 148         return devtype;
 149 }
 150
 151 /**
 152  * udev_device_get_subsystem:
 153  * @udev_device: udev device
 154  *
 155  * Retrieve the subsystem string of the udev device. The string does not
 156  * contain any "/".
 157  *
 158  * Returns: the subsystem name of the udev device, or #NULL if it cannot be determined
 159  **/
 160 _public_ const char *udev_device_get_subsystem(struct udev_device *udev_device)
 161 {
 162         const char *subsystem;
 163         int r;
 164
 165         assert_return_errno(udev_device, NULL, EINVAL);
 166
 167         r = sd_device_get_subsystem(udev_device->device, &subsystem);
 168         if (r < 0) {
 169                 errno = -r;
 170                 return NULL;
 171         } else if (!subsystem)
 172                 errno = ENODATA;
 173
 174         return subsystem;
 175 }
 176
 177 /**
 178  * udev_device_get_property_value:
 179  * @udev_device: udev device
 180  * @key: property name
 181  *
 182  * Get the value of a given property.
 183  *
 184  * Returns: the property string, or #NULL if there is no such property.
 185  **/
 186 _public_ const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key)
 187 {
 188         const char *value = NULL;
 189         int r;
 190
 191         assert_return_errno(udev_device && key, NULL, EINVAL);
 192
 193         r = sd_device_get_property_value(udev_device->device, key, &value);
 194         if (r < 0) {
 195                 errno = -r;
 196                 return NULL;
 197         }
 198
 199         return value;
 200 }
 201
 202 struct udev_device *udev_device_new(struct udev *udev) {
 203         struct udev_device *udev_device;
 204
 205         assert_return_errno(udev, NULL, EINVAL);
 206
 207         udev_device = new0(struct udev_device, 1);
 208         if (!udev_device) {
 209                 errno = ENOMEM;
 210                 return NULL;
 211         }
 212         udev_device->refcount = 1;
 213         udev_device->udev = udev;
 214         udev_list_init(udev, &udev_device->properties, true);
 215         udev_list_init(udev, &udev_device->tags, true);
 216         udev_list_init(udev, &udev_device->sysattrs, true);
 217         udev_list_init(udev, &udev_device->devlinks, true);
 218
 219         return udev_device;
 220 }
 221
 222 /**
 223  * udev_device_new_from_syspath:
 224  * @udev: udev library context
 225  * @syspath: sys device path including sys directory
 226  *
 227  * Create new udev device, and fill in information from the sys
 228  * device and the udev database entry. The syspath is the absolute
 229  * path to the device, including the sys mount point.
 230  *
 231  * The initial refcount is 1, and needs to be decremented to
 232  * release the resources of the udev device.
 233  *
 234  * Returns: a new udev device, or #NULL, if it does not exist
 235  **/
 236 _public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath) {
 237         struct udev_device *udev_device;
 238         int r;
 239
 240         udev_device = udev_device_new(udev);
 241         if (!udev_device)
 242                 return NULL;
 243
 244         r = sd_device_new_from_syspath(&udev_device->device, syspath);
 245         if (r < 0) {
 246                 errno = -r;
 247                 udev_device_unref(udev_device);
 248                 return NULL;
 249         }
 250
 251         return udev_device;
 252 }
 253
 254 /**
 255  * udev_device_new_from_devnum:
 256  * @udev: udev library context
 257  * @type: char or block device
 258  * @devnum: device major/minor number
 259  *
 260  * Create new udev device, and fill in information from the sys
 261  * device and the udev database entry. The device is looked-up
 262  * by its major/minor number and type. Character and block device
 263  * numbers are not unique across the two types.
 264  *
 265  * The initial refcount is 1, and needs to be decremented to
 266  * release the resources of the udev device.
 267  *
 268  * Returns: a new udev device, or #NULL, if it does not exist
 269  **/
 270 _public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 271 {
 272         struct udev_device *udev_device;
 273         int r;
 274
 275         udev_device = udev_device_new(udev);
 276         if (!udev_device)
 277                 return NULL;
 278
 279         r = sd_device_new_from_devnum(&udev_device->device, type, devnum);
 280         if (r < 0) {
 281                 errno = -r;
 282                 udev_device_unref(udev_device);
 283                 return NULL;
 284         }
 285
 286         return udev_device;
 287 }
 288
 289 /**
 290  * udev_device_new_from_device_id:
 291  * @udev: udev library context
 292  * @id: text string identifying a kernel device
 293  *
 294  * Create new udev device, and fill in information from the sys
 295  * device and the udev database entry. The device is looked-up
 296  * by a special string:
 297  *   b8:2          - block device major:minor
 298  *   c128:1        - char device major:minor
 299  *   n3            - network device ifindex
 300  *   +sound:card29 - kernel driver core subsystem:device name
 301  *
 302  * The initial refcount is 1, and needs to be decremented to
 303  * release the resources of the udev device.
 304  *
 305  * Returns: a new udev device, or #NULL, if it does not exist
 306  **/
 307 _public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id)
 308 {
 309         struct udev_device *udev_device;
 310         int r;
 311
 312         udev_device = udev_device_new(udev);
 313         if (!udev_device)
 314                 return NULL;
 315
 316         r = sd_device_new_from_device_id(&udev_device->device, id);
 317         if (r < 0) {
 318                 errno = -r;
 319                 udev_device_unref(udev_device);
 320                 return NULL;
 321         }
 322
 323         return udev_device;
 324 }
 325
 326 /**
 327  * udev_device_new_from_subsystem_sysname:
 328  * @udev: udev library context
 329  * @subsystem: the subsystem of the device
 330  * @sysname: the name of the device
 331  *
 332  * Create new udev device, and fill in information from the sys device
 333  * and the udev database entry. The device is looked up by the subsystem
 334  * and name string of the device, like "mem" / "zero", or "block" / "sda".
 335  *
 336  * The initial refcount is 1, and needs to be decremented to
 337  * release the resources of the udev device.
 338  *
 339  * Returns: a new udev device, or #NULL, if it does not exist
 340  **/
 341 _public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 342 {
 343         struct udev_device *udev_device;
 344         int r;
 345
 346         udev_device = udev_device_new(udev);
 347         if (!udev_device)
 348                 return NULL;
 349
 350         r = sd_device_new_from_subsystem_sysname(&udev_device->device, subsystem, sysname);
 351         if (r < 0) {
 352                 errno = -r;
 353                 udev_device_unref(udev_device);
 354                 return NULL;
 355         }
 356
 357         return udev_device;
 358 }
 359
 360 /**
 361  * udev_device_new_from_environment
 362  * @udev: udev library context
 363  *
 364  * Create new udev device, and fill in information from the
 365  * current process environment. This only works reliable if
 366  * the process is called from a udev rule. It is usually used
 367  * for tools executed from IMPORT= rules.
 368  *
 369  * The initial refcount is 1, and needs to be decremented to
 370  * release the resources of the udev device.
 371  *
 372  * Returns: a new udev device, or #NULL, if it does not exist
 373  **/
 374 _public_ struct udev_device *udev_device_new_from_environment(struct udev *udev)
 375 {
 376         struct udev_device *udev_device;
 377         int r;
 378
 379         udev_device = udev_device_new(udev);
 380         if (!udev_device)
 381                 return NULL;
 382
 383         r = device_new_from_strv(&udev_device->device, environ);
 384         if (r < 0) {
 385                 errno = -r;
 386                 udev_device_unref(udev_device);
 387                 return NULL;
 388         }
 389
 390         return udev_device;
 391 }
 392
 393 static struct udev_device *device_new_from_parent(struct udev_device *child)
 394 {
 395         struct udev_device *parent;
 396         int r;
 397
 398         assert_return_errno(child, NULL, EINVAL);
 399
 400         parent = udev_device_new(child->udev);
 401         if (!parent)
 402                 return NULL;
 403
 404         r = sd_device_get_parent(child->device, &parent->device);
 405         if (r < 0) {
 406                 errno = -r;
 407                 udev_device_unref(parent);
 408                 return NULL;
 409         }
 410
 411         /* the parent is unref'ed with the child, so take a ref from libudev as well */
 412         sd_device_ref(parent->device);
 413
 414         return parent;
 415 }
 416
 417 /**
 418  * udev_device_get_parent:
 419  * @udev_device: the device to start searching from
 420  *
 421  * Find the next parent device, and fill in information from the sys
 422  * device and the udev database entry.
 423  *
 424  * Returned device is not referenced. It is attached to the child
 425  * device, and will be cleaned up when the child device is cleaned up.
 426  *
 427  * It is not necessarily just the upper level directory, empty or not
 428  * recognized sys directories are ignored.
 429  *
 430  * It can be called as many times as needed, without caring about
 431  * references.
 432  *
 433  * Returns: a new udev device, or #NULL, if it no parent exist.
 434  **/
 435 _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 436 {
 437         assert_return_errno(udev_device, NULL, EINVAL);
 438
 439         if (!udev_device->parent_set) {
 440                 udev_device->parent_set = true;
 441                 udev_device->parent = device_new_from_parent(udev_device);
 442         }
 443
 444         /* TODO: errno will differ here in case parent == NULL */
 445         return udev_device->parent;
 446 }
 447
 448 /**
 449  * udev_device_get_parent_with_subsystem_devtype:
 450  * @udev_device: udev device to start searching from
 451  * @subsystem: the subsystem of the device
 452  * @devtype: the type (DEVTYPE) of the device
 453  *
 454  * Find the next parent device, with a matching subsystem and devtype
 455  * value, and fill in information from the sys device and the udev
 456  * database entry.
 457  *
 458  * If devtype is #NULL, only subsystem is checked, and any devtype will
 459  * match.
 460  *
 461  * Returned device is not referenced. It is attached to the child
 462  * device, and will be cleaned up when the child device is cleaned up.
 463  *
 464  * It can be called as many times as needed, without caring about
 465  * references.
 466  *
 467  * Returns: a new udev device, or #NULL if no matching parent exists.
 468  **/
 469 _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
 470 {
 471         sd_device *parent;
 472         int r;
 473
 474         assert_return_errno(udev_device, NULL, EINVAL);
 475
 476         /* this relies on the fact that finding the subdevice of a parent or the
 477            parent of a subdevice commute */
 478
 479         /* first find the correct sd_device */
 480         r = sd_device_get_parent_with_subsystem_devtype(udev_device->device, subsystem, devtype, &parent);
 481         if (r < 0) {
 482                 errno = -r;
 483                 return NULL;
 484         }
 485
 486         /* then walk the chain of udev_device parents until the corresponding
 487            one is found */
 488         while ((udev_device = udev_device_get_parent(udev_device))) {
 489                 if (udev_device->device == parent)
 490                         return udev_device;
 491         }
 492
 493         errno = ENOENT;
 494         return NULL;
 495 }
 496
 497 /**
 498  * udev_device_get_udev:
 499  * @udev_device: udev device
 500  *
 501  * Retrieve the udev library context the device was created with.
 502  *
 503  * Returns: the udev library context
 504  **/
 505 _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
 506 {
 507         assert_return_errno(udev_device, NULL, EINVAL);
 508
 509         return udev_device->udev;
 510 }
 511
 512 /**
 513  * udev_device_ref:
 514  * @udev_device: udev device
 515  *
 516  * Take a reference of a udev device.
 517  *
 518  * Returns: the passed udev device
 519  **/
 520 _public_ struct udev_device *udev_device_ref(struct udev_device *udev_device)
 521 {
 522         if (udev_device)
 523                 udev_device->refcount++;
 524
 525         return udev_device;
 526 }
 527
 528 /**
 529  * udev_device_unref:
 530  * @udev_device: udev device
 531  *
 532  * Drop a reference of a udev device. If the refcount reaches zero,
 533  * the resources of the device will be released.
 534  *
 535  * Returns: #NULL
 536  **/
 537 _public_ struct udev_device *udev_device_unref(struct udev_device *udev_device)
 538 {
 539         if (udev_device && (-- udev_device->refcount) == 0) {
 540                 sd_device_unref(udev_device->device);
 541                 udev_device_unref(udev_device->parent);
 542
 543                 udev_list_cleanup(&udev_device->properties);
 544                 udev_list_cleanup(&udev_device->sysattrs);
 545                 udev_list_cleanup(&udev_device->tags);
 546                 udev_list_cleanup(&udev_device->devlinks);
 547
 548                 free(udev_device);
 549         }
 550
 551         return NULL;
 552 }
 553
 554 /**
 555  * udev_device_get_devpath:
 556  * @udev_device: udev device
 557  *
 558  * Retrieve the kernel devpath value of the udev device. The path
 559  * does not contain the sys mount point, and starts with a '/'.
 560  *
 561  * Returns: the devpath of the udev device
 562  **/
 563 _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
 564 {
 565         const char *devpath;
 566         int r;
 567
 568         assert_return_errno(udev_device, NULL, EINVAL);
 569
 570         r = sd_device_get_devpath(udev_device->device, &devpath);
 571         if (r < 0) {
 572                 errno = -r;
 573                 return NULL;
 574         }
 575
 576         return devpath;
 577 }
 578
 579 /**
 580  * udev_device_get_syspath:
 581  * @udev_device: udev device
 582  *
 583  * Retrieve the sys path of the udev device. The path is an
 584  * absolute path and starts with the sys mount point.
 585  *
 586  * Returns: the sys path of the udev device
 587  **/
 588 _public_ const char *udev_device_get_syspath(struct udev_device *udev_device)
 589 {
 590         const char *syspath;
 591         int r;
 592
 593         assert_return_errno(udev_device, NULL, EINVAL);
 594
 595         r = sd_device_get_syspath(udev_device->device, &syspath);
 596         if (r < 0) {
 597                 errno = -r;
 598                 return NULL;
 599         }
 600
 601         return syspath;
 602 }
 603
 604 /**
 605  * udev_device_get_sysname:
 606  * @udev_device: udev device
 607  *
 608  * Get the kernel device name in /sys.
 609  *
 610  * Returns: the name string of the device
 611  **/
 612 _public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
 613 {
 614         const char *sysname;
 615         int r;
 616
 617         assert_return_errno(udev_device, NULL, EINVAL);
 618
 619         r = sd_device_get_sysname(udev_device->device, &sysname);
 620         if (r < 0) {
 621                 errno = -r;
 622                 return NULL;
 623         }
 624
 625         return sysname;
 626 }
 627
 628 /**
 629  * udev_device_get_sysnum:
 630  * @udev_device: udev device
 631  *
 632  * Get the instance number of the device.
 633  *
 634  * Returns: the trailing number string of the device name
 635  **/
 636 _public_ const char *udev_device_get_sysnum(struct udev_device *udev_device)
 637 {
 638         const char *sysnum;
 639         int r;
 640
 641         assert_return_errno(udev_device, NULL, EINVAL);
 642
 643         r = sd_device_get_sysnum(udev_device->device, &sysnum);
 644         if (r < 0) {
 645                 errno = -r;
 646                 return NULL;
 647         }
 648
 649         return sysnum;
 650 }
 651
 652 /**
 653  * udev_device_get_devnode:
 654  * @udev_device: udev device
 655  *
 656  * Retrieve the device node file name belonging to the udev device.
 657  * The path is an absolute path, and starts with the device directory.
 658  *
 659  * Returns: the device node file name of the udev device, or #NULL if no device node exists
 660  **/
 661 _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
 662 {
 663         const char *devnode;
 664         int r;
 665
 666         assert_return_errno(udev_device, NULL, EINVAL);
 667
 668         r = sd_device_get_devname(udev_device->device, &devnode);
 669         if (r < 0) {
 670                 errno = -r;
 671                 return NULL;
 672         }
 673
 674         return devnode;
 675 }
 676
 677 /**
 678  * udev_device_get_devlinks_list_entry:
 679  * @udev_device: udev device
 680  *
 681  * Retrieve the list of device links pointing to the device file of
 682  * the udev device. The next list entry can be retrieved with
 683  * udev_list_entry_get_next(), which returns #NULL if no more entries exist.
 684  * The devlink path can be retrieved from the list entry by
 685  * udev_list_entry_get_name(). The path is an absolute path, and starts with
 686  * the device directory.
 687  *
 688  * Returns: the first entry of the device node link list
 689  **/
 690 _public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
 691 {
 692         assert_return_errno(udev_device, NULL, EINVAL);
 693
 694         if (device_get_devlinks_generation(udev_device->device) != udev_device->devlinks_generation ||
 695             !udev_device->devlinks_read) {
 696                 const char *devlink;
 697
 698                 udev_list_cleanup(&udev_device->devlinks);
 699
 700                 FOREACH_DEVICE_DEVLINK(udev_device->device, devlink)
 701                         udev_list_entry_add(&udev_device->devlinks, devlink, NULL);
 702
 703                 udev_device->devlinks_read = true;
 704                 udev_device->devlinks_generation = device_get_devlinks_generation(udev_device->device);
 705         }
 706
 707         return udev_list_get_entry(&udev_device->devlinks);
 708 }
 709
 710 /**
 711  * udev_device_get_event_properties_entry:
 712  * @udev_device: udev device
 713  *
 714  * Retrieve the list of key/value device properties of the udev
 715  * device. The next list entry can be retrieved with udev_list_entry_get_next(),
 716  * which returns #NULL if no more entries exist. The property name
 717  * can be retrieved from the list entry by udev_list_entry_get_name(),
 718  * the property value by udev_list_entry_get_value().
 719  *
 720  * Returns: the first entry of the property list
 721  **/
 722 _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
 723 {
 724         assert_return_errno(udev_device, NULL, EINVAL);
 725
 726         if (device_get_properties_generation(udev_device->device) != udev_device->properties_generation ||
 727             !udev_device->properties_read) {
 728                 const char *key, *value;
 729
 730                 udev_list_cleanup(&udev_device->properties);
 731
 732                 FOREACH_DEVICE_PROPERTY(udev_device->device, key, value)
 733                         udev_list_entry_add(&udev_device->properties, key, value);
 734
 735                 udev_device->properties_read = true;
 736                 udev_device->properties_generation = device_get_properties_generation(udev_device->device);
 737         }
 738
 739         return udev_list_get_entry(&udev_device->properties);
 740 }
 741
 742 /**
 743  * udev_device_get_action:
 744  * @udev_device: udev device
 745  *
 746  * This is only valid if the device was received through a monitor. Devices read from
 747  * sys do not have an action string. Usual actions are: add, remove, change, online,
 748  * offline.
 749  *
 750  * Returns: the kernel action value, or #NULL if there is no action value available.
 751  **/
 752 _public_ const char *udev_device_get_action(struct udev_device *udev_device) {
 753         const char *action = NULL;
 754         int r;
 755
 756         assert_return_errno(udev_device, NULL, EINVAL);
 757
 758         r = sd_device_get_property_value(udev_device->device, "ACTION", &action);
 759         if (r < 0 && r != -ENOENT) {
 760                 errno = -r;
 761                 return NULL;
 762         }
 763
 764         return action;
 765 }
 766
 767 /**
 768  * udev_device_get_usec_since_initialized:
 769  * @udev_device: udev device
 770  *
 771  * Return the number of microseconds passed since udev set up the
 772  * device for the first time.
 773  *
 774  * This is only implemented for devices with need to store properties
 775  * in the udev database. All other devices return 0 here.
 776  *
 777  * Returns: the number of microseconds since the device was first seen.
 778  **/
 779 _public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device)
 780 {
 781         usec_t ts;
 782         int r;
 783
 784         assert_return(udev_device, -EINVAL);
 785
 786         r = sd_device_get_usec_since_initialized(udev_device->device, &ts);
 787         if (r < 0) {
 788                 errno = EINVAL;
 789                 return 0;
 790         }
 791
 792         return ts;
 793 }
 794
 795 /**
 796  * udev_device_get_sysattr_value:
 797  * @udev_device: udev device
 798  * @sysattr: attribute name
 799  *
 800  * The retrieved value is cached in the device. Repeated calls will return the same
 801  * value and not open the attribute again.
 802  *
 803  * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
 804  **/
 805 _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
 806 {
 807         const char *value;
 808         int r;
 809
 810         assert_return_errno(udev_device, NULL, EINVAL);
 811
 812         r = sd_device_get_sysattr_value(udev_device->device, sysattr, &value);
 813         if (r < 0) {
 814                 errno = -r;
 815                 return NULL;
 816         }
 817
 818         return value;
 819 }
 820
 821 /**
 822  * udev_device_set_sysattr_value:
 823  * @udev_device: udev device
 824  * @sysattr: attribute name
 825  * @value: new value to be set
 826  *
 827  * Update the contents of the sys attribute and the cached value of the device.
 828  *
 829  * Returns: Negative error code on failure or 0 on success.
 830  **/
 831 _public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value)
 832 {
 833         int r;
 834
 835         assert_return(udev_device, -EINVAL);
 836
 837         r = sd_device_set_sysattr_value(udev_device->device, sysattr, value);
 838         if (r < 0)
 839                 return r;
 840
 841         return 0;
 842 }
 843
 844 /**
 845  * udev_device_get_sysattr_list_entry:
 846  * @udev_device: udev device
 847  *
 848  * Retrieve the list of available sysattrs, with value being empty;
 849  * This just return all available sysfs attributes for a particular
 850  * device without reading their values.
 851  *
 852  * Returns: the first entry of the property list
 853  **/
 854 _public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
 855 {
 856         assert_return_errno(udev_device, NULL, EINVAL);
 857
 858         if (!udev_device->sysattrs_read) {
 859                 const char *sysattr;
 860
 861                 udev_list_cleanup(&udev_device->sysattrs);
 862
 863                 FOREACH_DEVICE_SYSATTR(udev_device->device, sysattr)
 864                         udev_list_entry_add(&udev_device->sysattrs, sysattr, NULL);
 865
 866                 udev_device->sysattrs_read = true;
 867         }
 868
 869         return udev_list_get_entry(&udev_device->sysattrs);
 870 }
 871
 872 /**
 873  * udev_device_get_is_initialized:
 874  * @udev_device: udev device
 875  *
 876  * Check if udev has already handled the device and has set up
 877  * device node permissions and context, or has renamed a network
 878  * device.
 879  *
 880  * This is only implemented for devices with a device node
 881  * or network interfaces. All other devices return 1 here.
 882  *
 883  * Returns: 1 if the device is set up. 0 otherwise.
 884  **/
 885 _public_ int udev_device_get_is_initialized(struct udev_device *udev_device)
 886 {
 887         int r, initialized;
 888
 889         assert_return(udev_device, -EINVAL);
 890
 891         r = sd_device_get_is_initialized(udev_device->device, &initialized);
 892         if (r < 0) {
 893                 errno = -r;
 894
 895                 return 0;
 896         }
 897
 898         return initialized;
 899 }
 900
 901 /**
 902  * udev_device_get_tags_list_entry:
 903  * @udev_device: udev device
 904  *
 905  * Retrieve the list of tags attached to the udev device. The next
 906  * list entry can be retrieved with udev_list_entry_get_next(),
 907  * which returns #NULL if no more entries exist. The tag string
 908  * can be retrieved from the list entry by udev_list_entry_get_name().
 909  *
 910  * Returns: the first entry of the tag list
 911  **/
 912 _public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device)
 913 {
 914         assert_return_errno(udev_device, NULL, EINVAL);
 915
 916         if (device_get_tags_generation(udev_device->device) != udev_device->tags_generation ||
 917             !udev_device->tags_read) {
 918                 const char *tag;
 919
 920                 udev_list_cleanup(&udev_device->tags);
 921
 922                 FOREACH_DEVICE_TAG(udev_device->device, tag)
 923                         udev_list_entry_add(&udev_device->tags, tag, NULL);
 924
 925                 udev_device->tags_read = true;
 926                 udev_device->tags_generation = device_get_tags_generation(udev_device->device);
 927         }
 928
 929         return udev_list_get_entry(&udev_device->tags);
 930 }
 931
 932 /**
 933  * udev_device_has_tag:
 934  * @udev_device: udev device
 935  * @tag: tag name
 936  *
 937  * Check if a given device has a certain tag associated.
 938  *
 939  * Returns: 1 if the tag is found. 0 otherwise.
 940  **/
 941 _public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag)
 942 {
 943         assert_return(udev_device, 0);
 944
 945         return sd_device_has_tag(udev_device->device, tag);
 946 }