Class UdevFunctions

java.lang.Object

oshi.ffm.ForeignFunctions

oshi.ffm.linux.UdevFunctions

public final class UdevFunctions
extends ForeignFunctions

FFM bindings for the udev (userspace device management) library.

libudev provides APIs to introspect and enumerate devices on the local Linux system. All udev objects are opaque MemorySegment handles. Callers must unref context, enumerate, and device handles when done.

Loading can be suppressed via the oshi.os.linux.allowudev configuration property.

Field Summary

Fields inherited from class ForeignFunctions

CAPTURE_CALL_STATE, CAPTURED_STATE_LAYOUT, ERRNO_HANDLE, LIBRARY_ARENA, LINKER, NATIVE_LONG_SIZE, NATIVE_POINTER_SIZE, NATIVE_SIZE_T_SIZE, SYMBOL_LOOKUP

Method Summary

Modifier and Type	Method	Description
static int	addMatchSubsystem(MemorySegment enumerate, String subsystem, Arena arena)	Allocates a native UTF-8 string in the given arena and calls udev_enumerate_add_match_subsystem(MemorySegment, MemorySegment).
static MemorySegment	deviceNewFromSyspath(MemorySegment udev, String syspath, Arena arena)	Allocates a native UTF-8 string in the given arena and calls udev_device_new_from_syspath(MemorySegment, MemorySegment).
static MemorySegment	getParentWithSubsystemDevtype(MemorySegment device, String subsystem, String devtype, Arena arena)	Allocates native UTF-8 strings in the given arena and calls udev_device_get_parent_with_subsystem_devtype(MemorySegment, MemorySegment, MemorySegment).
static String	getPropertyValue(MemorySegment device, String key, Arena arena)	Allocates a native UTF-8 string in the given arena and calls udev_device_get_property_value(MemorySegment, MemorySegment).
static String	getString(MemorySegment ptr, Arena arena)	Reads a udev string result (syspath, sysattr, property, etc.) into a Java String, using the provided arena for the reinterpret scope.
static String	getSysattrValue(MemorySegment device, String sysattr, Arena arena)	Allocates native UTF-8 strings in the given arena and calls udev_device_get_sysattr_value(MemorySegment, MemorySegment).
static boolean	isAvailable()	Returns whether libudev was successfully loaded and all symbols bound.
static MemorySegment	udev_device_get_devnode(MemorySegment device)	Gets the devnode of a device (e.g.
static MemorySegment	udev_device_get_devtype(MemorySegment device)	Gets the devtype of a device (e.g.
static MemorySegment	udev_device_get_parent(MemorySegment device)	Gets the parent device.
static MemorySegment	udev_device_get_parent_with_subsystem_devtype(MemorySegment device, MemorySegment subsystem, MemorySegment devtype)	Gets the first parent device matching a subsystem and devtype.
static MemorySegment	udev_device_get_property_value(MemorySegment device, MemorySegment key)	Retrieves a udev property value from a device.
static MemorySegment	udev_device_get_subsystem(MemorySegment device)	Gets the subsystem of a device (e.g.
static MemorySegment	udev_device_get_sysattr_value(MemorySegment device, MemorySegment sysattr)	Retrieves a sysfs attribute value from a device.
static MemorySegment	udev_device_get_sysname(MemorySegment device)	Gets the sysname of a device.
static MemorySegment	udev_device_get_syspath(MemorySegment device)	Gets the syspath of a device.
static MemorySegment	udev_device_new_from_syspath(MemorySegment udev, MemorySegment syspath)	Creates a udev device from a syspath.
static void	udev_device_unref(MemorySegment device)	Drops a reference to a udev device.
static int	udev_enumerate_add_match_subsystem(MemorySegment enumerate, MemorySegment subsystem)	Adds a subsystem filter to the enumerate object.
static MemorySegment	udev_enumerate_get_list_entry(MemorySegment enumerate)	Gets the first list entry from an enumerate object.
static MemorySegment	udev_enumerate_new(MemorySegment udev)	Creates a new udev enumerate object.
static int	udev_enumerate_scan_devices(MemorySegment enumerate)	Scans /sys for devices matching the enumerate filters.
static void	udev_enumerate_unref(MemorySegment enumerate)	Drops a reference to a udev enumerate object.
static MemorySegment	udev_list_entry_get_name(MemorySegment entry)	Gets the name (syspath) of a list entry.
static MemorySegment	udev_list_entry_get_next(MemorySegment entry)	Gets the next entry in a list.
static MemorySegment	udev_new()	Allocates a new udev context.
static void	udev_unref(MemorySegment udev)	Drops a reference to a udev context.

Methods inherited from class ForeignFunctions

downcall, getByteArrayFromNativePointer, getErrno, getStringFromNativePointer, getStructFromNativePointer, lib, libraryLookup

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

isAvailable

public static boolean isAvailable()

Returns whether libudev was successfully loaded and all symbols bound.

Returns:

true if libudev is available

udev_new

public static MemorySegment udev_new()
                              throws Throwable

Allocates a new udev context. The caller must call udev_unref when done.

Returns:

opaque udev context handle, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_unref

public static void udev_unref(MemorySegment udev)
                       throws Throwable

Drops a reference to a udev context. Once the reference count hits 0, the context is destroyed.

Parameters:

udev - the udev context handle

Throws:

Throwable - if the native call fails

udev_enumerate_new

public static MemorySegment udev_enumerate_new(MemorySegment udev)
                                        throws Throwable

Creates a new udev enumerate object. The caller must call udev_enumerate_unref when done.

Parameters:

udev - the udev context handle

Returns:

opaque enumerate handle, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_enumerate_unref

public static void udev_enumerate_unref(MemorySegment enumerate)
                                 throws Throwable

Drops a reference to a udev enumerate object.

Parameters:

enumerate - the enumerate handle

Throws:

Throwable - if the native call fails

udev_enumerate_add_match_subsystem

public static int udev_enumerate_add_match_subsystem(MemorySegment enumerate,
 MemorySegment subsystem)
                                              throws Throwable

Adds a subsystem filter to the enumerate object.

Parameters:

enumerate - the enumerate handle

subsystem - the subsystem name as a native string segment

Returns:

0 or greater on success

Throws:

Throwable - if the native call fails

udev_enumerate_scan_devices

public static int udev_enumerate_scan_devices(MemorySegment enumerate)
                                       throws Throwable

Scans /sys for devices matching the enumerate filters.

Parameters:

enumerate - the enumerate handle

Returns:

0 or greater on success

Throws:

Throwable - if the native call fails

udev_enumerate_get_list_entry

public static MemorySegment udev_enumerate_get_list_entry(MemorySegment enumerate)
                                                   throws Throwable

Gets the first list entry from an enumerate object.

Parameters:

enumerate - the enumerate handle

Returns:

the first list entry handle, or MemorySegment.NULL if empty

Throws:

Throwable - if the native call fails

udev_list_entry_get_next

public static MemorySegment udev_list_entry_get_next(MemorySegment entry)
                                              throws Throwable

Gets the next entry in a list.

Parameters:

entry - the current list entry handle

Returns:

the next list entry handle, or MemorySegment.NULL if none

Throws:

Throwable - if the native call fails

udev_list_entry_get_name

public static MemorySegment udev_list_entry_get_name(MemorySegment entry)
                                              throws Throwable

Gets the name (syspath) of a list entry.

Parameters:

entry - the list entry handle

Returns:

a native pointer to the name string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_new_from_syspath

public static MemorySegment udev_device_new_from_syspath(MemorySegment udev,
 MemorySegment syspath)
                                                  throws Throwable

Creates a udev device from a syspath. The caller must call udev_device_unref when done.

Parameters:

udev - the udev context handle

syspath - native string segment for the /sys path

Returns:

opaque device handle, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_unref

public static void udev_device_unref(MemorySegment device)
                              throws Throwable

Drops a reference to a udev device.

Parameters:

device - the device handle

Throws:

Throwable - if the native call fails

udev_device_get_parent

public static MemorySegment udev_device_get_parent(MemorySegment device)
                                            throws Throwable

Gets the parent device. The returned handle is owned by the child; do not unref it separately.

Parameters:

device - the device handle

Returns:

the parent device handle, or MemorySegment.NULL if none

Throws:

Throwable - if the native call fails

udev_device_get_parent_with_subsystem_devtype

public static MemorySegment udev_device_get_parent_with_subsystem_devtype(MemorySegment device,
 MemorySegment subsystem,
 MemorySegment devtype)
                                                                   throws Throwable

Gets the first parent device matching a subsystem and devtype. The returned handle is owned by the child; do not unref it separately.

Parameters:

device - the device handle

subsystem - native string segment for the subsystem to match

devtype - native string segment for the devtype to match

Returns:

the matching parent device handle, or MemorySegment.NULL if none

Throws:

Throwable - if the native call fails

udev_device_get_syspath

public static MemorySegment udev_device_get_syspath(MemorySegment device)
                                             throws Throwable

Gets the syspath of a device.

Parameters:

device - the device handle

Returns:

a native pointer to the syspath string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_sysname

public static MemorySegment udev_device_get_sysname(MemorySegment device)
                                             throws Throwable

Gets the sysname of a device.

Parameters:

device - the device handle

Returns:

a native pointer to the sysname string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_devnode

public static MemorySegment udev_device_get_devnode(MemorySegment device)
                                             throws Throwable

Gets the devnode of a device (e.g. /dev/sda).

Parameters:

device - the device handle

Returns:

a native pointer to the devnode string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_devtype

public static MemorySegment udev_device_get_devtype(MemorySegment device)
                                             throws Throwable

Gets the devtype of a device (e.g. "disk", "partition", "usb_device").

Parameters:

device - the device handle

Returns:

a native pointer to the devtype string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_subsystem

public static MemorySegment udev_device_get_subsystem(MemorySegment device)
                                               throws Throwable

Gets the subsystem of a device (e.g. "block", "net", "usb").

Parameters:

device - the device handle

Returns:

a native pointer to the subsystem string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_sysattr_value

public static MemorySegment udev_device_get_sysattr_value(MemorySegment device,
 MemorySegment sysattr)
                                                   throws Throwable

Retrieves a sysfs attribute value from a device.

Parameters:

device - the device handle

sysattr - native string segment for the attribute name

Returns:

a native pointer to the attribute value string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

udev_device_get_property_value

public static MemorySegment udev_device_get_property_value(MemorySegment device,
 MemorySegment key)
                                                    throws Throwable

Retrieves a udev property value from a device.

Parameters:

device - the device handle

key - native string segment for the property key

Returns:

a native pointer to the property value string, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

getString

public static String getString(MemorySegment ptr,
 Arena arena)

Reads a udev string result (syspath, sysattr, property, etc.) into a Java String, using the provided arena for the reinterpret scope.

Parameters:

ptr - the native pointer returned by a udev getter

arena - the arena to scope the reinterpreted segment to

Returns:

the Java string, or null if the pointer is null or MemorySegment.NULL

addMatchSubsystem

public static int addMatchSubsystem(MemorySegment enumerate,
 String subsystem,
 Arena arena)
                             throws Throwable

Allocates a native UTF-8 string in the given arena and calls udev_enumerate_add_match_subsystem(MemorySegment, MemorySegment).

Parameters:

enumerate - the enumerate handle

subsystem - the subsystem name

arena - the arena to allocate the string in

Returns:

0 or greater on success

Throws:

Throwable - if the native call fails

deviceNewFromSyspath

public static MemorySegment deviceNewFromSyspath(MemorySegment udev,
 String syspath,
 Arena arena)
                                          throws Throwable

Allocates a native UTF-8 string in the given arena and calls udev_device_new_from_syspath(MemorySegment, MemorySegment).

Parameters:

udev - the udev context handle

syspath - the syspath string

arena - the arena to allocate the string in

Returns:

opaque device handle, or MemorySegment.NULL on failure

Throws:

Throwable - if the native call fails

getSysattrValue

public static String getSysattrValue(MemorySegment device,
 String sysattr,
 Arena arena)
                              throws Throwable

Allocates native UTF-8 strings in the given arena and calls udev_device_get_sysattr_value(MemorySegment, MemorySegment).

Parameters:

device - the device handle

sysattr - the attribute name

arena - the arena to allocate the string in

Returns:

the attribute value, or null if not found

Throws:

Throwable - if the native call fails

getPropertyValue

public static String getPropertyValue(MemorySegment device,
 String key,
 Arena arena)
                               throws Throwable

Allocates a native UTF-8 string in the given arena and calls udev_device_get_property_value(MemorySegment, MemorySegment).

Parameters:

device - the device handle

key - the property key

arena - the arena to allocate the string in

Returns:

the property value, or null if not found

Throws:

Throwable - if the native call fails

getParentWithSubsystemDevtype

public static MemorySegment getParentWithSubsystemDevtype(MemorySegment device,
 String subsystem,
 String devtype,
 Arena arena)
                                                   throws Throwable

Allocates native UTF-8 strings in the given arena and calls udev_device_get_parent_with_subsystem_devtype(MemorySegment, MemorySegment, MemorySegment).

Parameters:

device - the device handle

subsystem - the subsystem to match

devtype - the devtype to match

arena - the arena to allocate strings in

Returns:

the matching parent device handle, or MemorySegment.NULL if none

Throws:

Throwable - if the native call fails