kernel/
ioctl.rs

1// SPDX-License-Identifier: GPL-2.0
2
3//! `ioctl()` number definitions.
4//!
5//! C header: [`include/asm-generic/ioctl.h`](srctree/include/asm-generic/ioctl.h)
6
7#![expect(non_snake_case)]
8
9use crate::build_assert;
10
11/// Build an ioctl number, analogous to the C macro of the same name.
12#[inline(always)]
13const fn _IOC(dir: u32, ty: u32, nr: u32, size: usize) -> u32 {
14    build_assert!(dir <= uapi::_IOC_DIRMASK);
15    build_assert!(ty <= uapi::_IOC_TYPEMASK);
16    build_assert!(nr <= uapi::_IOC_NRMASK);
17    build_assert!(size <= (uapi::_IOC_SIZEMASK as usize));
18
19    (dir << uapi::_IOC_DIRSHIFT)
20        | (ty << uapi::_IOC_TYPESHIFT)
21        | (nr << uapi::_IOC_NRSHIFT)
22        | ((size as u32) << uapi::_IOC_SIZESHIFT)
23}
24
25/// Build an ioctl number for an argumentless ioctl.
26#[inline(always)]
27pub const fn _IO(ty: u32, nr: u32) -> u32 {
28    _IOC(uapi::_IOC_NONE, ty, nr, 0)
29}
30
31/// Build an ioctl number for a read-only ioctl.
32#[inline(always)]
33pub const fn _IOR<T>(ty: u32, nr: u32) -> u32 {
34    _IOC(uapi::_IOC_READ, ty, nr, core::mem::size_of::<T>())
35}
36
37/// Build an ioctl number for a write-only ioctl.
38#[inline(always)]
39pub const fn _IOW<T>(ty: u32, nr: u32) -> u32 {
40    _IOC(uapi::_IOC_WRITE, ty, nr, core::mem::size_of::<T>())
41}
42
43/// Build an ioctl number for a read-write ioctl.
44#[inline(always)]
45pub const fn _IOWR<T>(ty: u32, nr: u32) -> u32 {
46    _IOC(
47        uapi::_IOC_READ | uapi::_IOC_WRITE,
48        ty,
49        nr,
50        core::mem::size_of::<T>(),
51    )
52}
53
54/// Get the ioctl direction from an ioctl number.
55pub const fn _IOC_DIR(nr: u32) -> u32 {
56    (nr >> uapi::_IOC_DIRSHIFT) & uapi::_IOC_DIRMASK
57}
58
59/// Get the ioctl type from an ioctl number.
60pub const fn _IOC_TYPE(nr: u32) -> u32 {
61    (nr >> uapi::_IOC_TYPESHIFT) & uapi::_IOC_TYPEMASK
62}
63
64/// Get the ioctl number from an ioctl number.
65pub const fn _IOC_NR(nr: u32) -> u32 {
66    (nr >> uapi::_IOC_NRSHIFT) & uapi::_IOC_NRMASK
67}
68
69/// Get the ioctl size from an ioctl number.
70pub const fn _IOC_SIZE(nr: u32) -> usize {
71    ((nr >> uapi::_IOC_SIZESHIFT) & uapi::_IOC_SIZEMASK) as usize
72}
kernel/ioctl.rs

kernel/
ioctl.rs
