32 bits to describe an ioctl: 0-7: NR (command for a given ioctl type) 8-15: TYPE (ioctl type) 16-29: SIZE (payload size) 30-31: DIR (direction of ioctl, can be: none/write/read/write-read)
const (
IocWrite = 1
IocRead = 2
IocNRBits = 8
IocTypeBits = 8
IocSizeBits = 14
IocDirBits = 2
IocNRMask = (1 << IocNRBits) - 1
IocTypeMask = (1 << IocTypeBits) - 1
IocSizeMask = (1 << IocSizeBits) - 1
IocDirMask = (1 << IocDirBits) - 1
IocTypeShift = IocNRBits
IocSizeShift = IocTypeShift + IocTypeBits
IocDirShift = IocSizeShift + IocSizeBits
IocWRBase = (IocRead | IocWrite) << IocDirShift
)
func Ioctl(f *os.File, command int, dataPtr unsafe.Pointer) error
Ioctl makes a syscall described by `command` with data `dataPtr` to device driver file `f`.