/
evdev.go
229 lines (192 loc) · 4.85 KB
/
evdev.go
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package evdev
import (
"errors"
"fmt"
"io"
"os"
"syscall"
"unsafe"
"golang.org/x/sys/unix"
)
type Device struct {
file *os.File
Name string
ID InputID
bits []byte
bitsREL, bitsABS, bitsLED, bitsKEY, bitsSW, bitsMSC, bitsFF, bitsSND []byte
}
func Open(path string) (*Device, error) {
file, err := os.Open(path)
if err != nil {
return nil, err
}
d := Device{file: file}
return &d, d.init()
}
func (d *Device) init() error {
conn, err := d.file.SyscallConn()
if err != nil {
return err
}
var buf [256]byte
err = cctl(conn, eviocgname(uintptr(len(buf))), &buf[0])
if err != nil {
return fmt.Errorf("get device name: %w", err)
}
d.Name = fromNTString(buf[:])
err = cctl(conn, eviocgid, &d.ID)
if err != nil {
return fmt.Errorf("get device info: %w", err)
}
var bits [0x1F]byte
err = cctl(conn, eviocgbit(0, uintptr(len(bits))), &bits[0])
if err != nil {
return fmt.Errorf("get device capabilities: %w", err)
}
d.bits = bits[:]
var bitsREL [(relCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(EvRel, uintptr(len(bitsREL)))), &bitsREL[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsREL = bitsREL[:]
var bitsABS [(absCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(EvAbs, uintptr(len(bitsABS)))), &bitsABS[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsABS = bitsABS[:]
var bitsLED [(ledCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(evLed, uintptr(len(bitsLED)))), &bitsLED[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsLED = bitsLED[:]
var bitsKEY [(keyCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(EvKey, uintptr(len(bitsKEY)))), &bitsKEY[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsKEY = bitsKEY[:]
var bitsSW [(swCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(EvSw, uintptr(len(bitsSW)))), &bitsSW[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsSW = bitsSW[:]
var bitsMSC [(mscCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(EvMsc, uintptr(len(bitsMSC)))), &bitsMSC[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsMSC = bitsMSC[:]
var bitsFF [(ffCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(evFf, uintptr(len(bitsFF)))), &bitsFF[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsFF = bitsFF[:]
var bitsSND [(sndCount + wordbits - 1) / 8]byte
err = cctl(conn, uintptr(eviocgbit(evSnd, uintptr(len(bitsSND)))), &bitsSND[0])
if err != nil {
return fmt.Errorf("get type bits: %w", err)
}
d.bitsSND = bitsSND[:]
return nil
}
func (d *Device) Close() error {
return d.file.Close()
}
func (d *Device) typeCodes(t uint16) []byte {
switch t {
case EvKey:
return d.bitsKEY
case EvRel:
return d.bitsREL
case EvAbs:
return d.bitsABS
case EvMsc:
return d.bitsMSC
case EvSw:
return d.bitsSW
case evLed:
return d.bitsLED
case evSnd:
return d.bitsSND
case evFf:
return d.bitsFF
default:
return nil
}
}
func (d *Device) HasEventType(t uint16) bool {
return isBitSet(d.bits, t)
}
func (d *Device) HasEventCode(t, code uint16) bool {
return d.HasEventType(t) && isBitSet(d.typeCodes(t), code)
}
func (d *Device) NextEvent() (InputEvent, error) {
type inputEvent struct {
_ [16]byte // TODO: Add timestamp support.
InputEvent
}
var ev [unsafe.Sizeof(inputEvent{})]byte
_, err := io.ReadFull(d.file, ev[:])
if err != nil {
return InputEvent{}, fmt.Errorf("read: %w", err)
}
return (*inputEvent)(unsafe.Pointer(&ev[0])).InputEvent, nil
}
type InputEvent struct {
Type uint16
Code uint16
Value int32
}
func (ev InputEvent) Is(t, code uint16) bool {
return (ev.Type == t) && (ev.Code == code)
}
type InputID struct {
BusType uint16
Vendor uint16
Product uint16
Version uint16
}
type inputAbsInfo struct {
Value int32
Minimum int32
Maximum int32
Fuzz int32
Flat int32
Resolution int32
}
func control(conn syscall.RawConn, f func(uintptr) error) error {
var ferr error
err := conn.Control(func(fd uintptr) { ferr = f(fd) })
return errors.Join(err, ferr)
}
func ioctl[T any](fd, name uintptr, data *T) unix.Errno {
_, _, err := unix.Syscall(unix.SYS_IOCTL, fd, name, uintptr(unsafe.Pointer(data)))
return err
}
func cctl[T any](conn syscall.RawConn, name uintptr, data *T) error {
return control(conn, func(fd uintptr) error {
return fromErrno(ioctl(fd, name, data))
})
}
func fromErrno(err unix.Errno) error {
if err == 0 {
return nil
}
return err
}
func isBitSet(bits []byte, bit uint16) bool {
return bits[bit/8]&(1<<(bit%8)) != 0
}
func fromNTString(b []byte) string {
for i, c := range b {
if c == 0 {
return unsafe.String(&b[0], i)
}
}
return unsafe.String(&b[0], len(b))
}