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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_DEVICE_GET_SYSPATH(3) sd_device_get_syspath SD_DEVICE_GET_SYSPATH(3)
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, const char **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
another 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.
Errors
Returned errors may indicate the following problems:
-EINVAL
A specified parameter is invalid.
Added in version 251.
-ENOENT
The requested field is not present in the device record.
Added in version 251.
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.
systemd(1), sd-device(3)
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
systemd 258~rc2 SD_DEVICE_GET_SYSPATH(3)
Pages that refer to this page: sd-device(3), systemd.directives(7), systemd.index(7), udevadm(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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