библиотека идентификации блочного устройства (block device identification library)
Имя (Name)
libblkid - block device identification library
Синопсис (Synopsis)
#include <blkid.h>
cc file.c -lblkid
Описание (Description)
The libblkid library is used to identify block devices (disks) as
to their content (e.g., filesystem type) as well as extracting
additional information such as filesystem labels/volume names,
unique identifiers/serial numbers. A common use is to allow use
of LABEL= and UUID= tags instead of hard-coding specific block
device names into configuration files.
The low-level part of the library also allows the extraction of
information about partitions and block device topology.
The high-level part of the library keeps information about block
devices in a cache file and is verified to still be valid before
being returned to the user (if the user has read permission on
the raw block device, otherwise not). The cache file also allows
unprivileged users (normally anyone other than root, or those not
in the "disk" group) to locate devices by label/id. The standard
location of the cache file can be overridden by the environment
variable BLKID_FILE.
In situations where one is getting information about a single
known device, it does not impact performance whether the cache is
used or not (unless you are not able to read the block device
directly).
The high-level part of the library supports two methods to
evaluate LABEL/UUID. It reads information directly from a block
device or read information from /dev/disk/by-* udev symlinks. The
udev is preferred method by default.
If you are dealing with multiple devices, use of the cache is
highly recommended (even if empty) as devices will be scanned at
most one time and the on-disk cache will be updated if possible.
In some cases (modular kernels), block devices are not even
visible until after they are accessed the first time, so it is
critical that there is some way to locate these devices without
enumerating only visible devices, so the use of the cache file is
required in this situation.
Конфигурационный файл (Config file)
The standard location of the /etc/blkid.conf config file can be
overridden by the environment variable BLKID_CONF. For more
details about the config file see blkid(8) man page.
