sd_device_get_syspath, sd_device_get_devpath, sd_device_get_sysname, sd_device_get_sysnum, sd_device_get_subsystem, sd_device_get_driver_subsystem, sd_device_get_devtype, sd_device_get_devname, sd_device_get_devnum, sd_device_get_ifindex, sd_device_get_driver, sd_device_get_diskseq, sd_device_get_device_id — Returns various fields of device objects
#include <systemd/sd-device.h>
int sd_device_get_syspath( | sd_device *device, |
const char **ret) ; |
int sd_device_get_devpath( | sd_device *device, |
const char **ret) ; |
int sd_device_get_sysname( | sd_device *device, |
const char **ret) ; |
int sd_device_get_sysnum( | sd_device *device, |
const char **ret) ; |
int sd_device_get_subsystem( | sd_device *device, |
const char **ret) ; |
int sd_device_get_driver_subsystem( | sd_device *device, |
const char **ret) ; |
int sd_device_get_devtype( | sd_device *device, |
const char **ret) ; |
int sd_device_get_devname( | sd_device *device, |
const char **ret) ; |
int sd_device_get_devnum( | sd_device *device, |
dev_t *ret) ; |
int sd_device_get_ifindex( | sd_device *device, |
int *ret) ; |
int sd_device_get_driver( | sd_device *device, |
const char **ret) ; |
int sd_device_get_diskseq( | sd_device *device, |
uint64_t *ret) ; |
int sd_device_get_device_id( | sd_device *device, |
uint64_t *ret) ; |
sd_device_get_syspath()
returns the sysfs path of the specified device record,
including the /sys
prefix. Example: /sys/devices/virtual/tty/tty7
sd_device_get_devpath()
returns the sysfs path of the specified device record,
excluding the /sys
prefix. Example: /devices/virtual/tty/tty7
sd_device_get_sysname()
returns the sysfs name of the specified device record,
i.e. the last component of the sysfs path. Example: "tty7
" for the device
/sys/devices/virtual/tty/tty7
sd_device_get_sysnum()
returns the sysfs device number of the specified device
record, i.e. the numeric suffix of the last component of the sysfs path. Example: "7
"
for the device /sys/devices/virtual/tty/tty7
sd_device_get_subsystem()
returns the kernel subsystem of the specified device
record. This is a short string fitting into a filename, and thus does not contain a slash and cannot be
empty. Example: "tty
", "block
" or "net
".
sd_device_get_driver_subsystem()
returns the connected bus type of the devices
loaded by the specified driver device record. For example, when "iwlwifi
" driver device
is specified, which is used by the wireless network interfaces connected to PCI bus, this function returns
"pci
". This function only succeeds when sd_device_get_subsystem()
returns "drivers
". Example: "pci
", "i2c
", or
"hid
".
sd_device_get_devtype()
returns the device type of the specified device
record, if the subsystem manages multiple types of devices. Example: for devices of the
"block
" subsystem this can be "disk
" or "partition
"
sd_device_get_devname()
returns the device node path of the specified device
record if the device has a device node. Example: for /sys/devices/virtual/tty/tty7
the string /dev/tty7
is typically returned.
sd_device_get_devnum()
returns the device node major/minor
(i.e. dev_t) of the specified device record if the device has a device node (i.e. the one
returned by sd_device_get_devname()
). For devices belonging to the
"block
" subsystem this refers to a block device node, in all other cases to a character
device node. Example: for the /sys/devices/virtual/tty/tty7
device this typically
returns the device number with major/minor "4:7
".
sd_device_get_ifindex()
returns the network interface index of the specified
device record, if the device encapsulates a network interface device, i.e. belongs to the
"net
" subsystem. Example: the "lo
" interface typically has interface
index 1.
sd_device_get_driver()
returns the kernel driver name attached to the
device. Note that the driver field is set on the devices consumed by the driver, not on the device
created by it. Example: a PCI device /sys/bus/pci/devices/0000:00:1f.6
might be
attached to a driver "e1000e
".
sd_device_get_diskseq()
returns the kernel disk sequence number of the block
device. This number monotonically increases whenever a backing medium of a block device changes without
the device name changing, and is relevant for block devices encapsulating devices with changing media
(e.g. floppy or CD-ROM), or loopback block devices. Only defined for block devices, i.e. those of
subsystem "block
".
sd_device_get_device_id()
returns the short string that identifies the device
record. When the device ID obtained by the function for a specified device record is passed to
sd_device_new_from_device_id()
, a new instance of the same device record will be
gained. When a block or character device is specified, which has corresponding device node, this returns
"b
" or "c
", respectively, followed by the device node major and minor
numbers separated with a colon. Example: "b259:1
" or "c10:121
". When a
network interface device is specified, this returns "n
" followed by the interface index,
which can be obtained by sd_device_get_ifindex()
. Example: "n1
".
When a device in the "driver
" subsystem is specified, this returns
"+drivers:
" followed by its driver subsystem and sysfs name separated with a colon.
Example: "+drivers:pci:iwlwifi
" for a driver device record whose driver subsystem is
"pci
" and sysfs name is "iwlwifi
",
When an other type of device is specified, this function returns "+
" followed by its
subsystem and sysfs name separated with a colon. Example: "+acpi:ACPI0003:00
",
"+input:input16
", or "+pci:0000:00:1f.6
".
On success, these calls return 0 or a positive integer. On failure, they return a negative errno-style error code.
Functions described here are available as a shared
library, which can be compiled against and linked to with the
libsystemd
pkg-config(1)
file.
The code described here uses
getenv(3),
which is declared to be not multi-thread-safe. This means that the code calling the functions described
here must not call
setenv(3)
from a parallel thread. It is recommended to only do calls to setenv()
from an early phase of the program when no other threads have been started.
sd_device_get_syspath()
,
sd_device_get_devpath()
,
sd_device_get_sysname()
,
sd_device_get_sysnum()
,
sd_device_get_subsystem()
,
sd_device_get_devtype()
,
sd_device_get_devname()
,
sd_device_get_devnum()
,
sd_device_get_ifindex()
,
sd_device_get_driver()
, and
sd_device_get_diskseq()
were added in version 251.
sd_device_get_driver_subsystem()
and
sd_device_get_device_id()
were added in version 257.