NAME

       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, sd_device_get_diskseq - Returns various fields of device
       objects

SYNOPSIS

       #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_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);

DESCRIPTION

       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_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".

RETURN VALUE

       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.

NOTES

       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.

HISTORY

       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.

SEE ALSO

       systemd(1)

systemd 255                                                                             SD_DEVICE_GET_SYSPATH(3)