ea76e08f4d
Add simple 1:1 wrappers of the C ioctl number manipulation functions. Since these are macros we cannot bindgen them directly, and since they should be usable in const context we cannot use helper wrappers, so we'll have to reimplement them in Rust. Thankfully, the C headers do declare defines for the relevant bitfield positions, so we don't need to duplicate that. Signed-off-by: Asahi Lina <lina@asahilina.net> Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-2-bca5fb4d4a12@asahilina.net [ Moved the `#![allow(non_snake_case)]` to the usual place. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
73 lines
2.0 KiB
Rust
73 lines
2.0 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! ioctl() number definitions
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//!
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//! C header: [`include/asm-generic/ioctl.h`](../../../../include/asm-generic/ioctl.h)
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#![allow(non_snake_case)]
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use crate::build_assert;
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/// Build an ioctl number, analogous to the C macro of the same name.
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#[inline(always)]
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const fn _IOC(dir: u32, ty: u32, nr: u32, size: usize) -> u32 {
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build_assert!(dir <= uapi::_IOC_DIRMASK);
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build_assert!(ty <= uapi::_IOC_TYPEMASK);
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build_assert!(nr <= uapi::_IOC_NRMASK);
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build_assert!(size <= (uapi::_IOC_SIZEMASK as usize));
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(dir << uapi::_IOC_DIRSHIFT)
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| (ty << uapi::_IOC_TYPESHIFT)
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| (nr << uapi::_IOC_NRSHIFT)
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| ((size as u32) << uapi::_IOC_SIZESHIFT)
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}
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/// Build an ioctl number for an argumentless ioctl.
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#[inline(always)]
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pub const fn _IO(ty: u32, nr: u32) -> u32 {
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_IOC(uapi::_IOC_NONE, ty, nr, 0)
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}
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/// Build an ioctl number for an read-only ioctl.
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#[inline(always)]
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pub const fn _IOR<T>(ty: u32, nr: u32) -> u32 {
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_IOC(uapi::_IOC_READ, ty, nr, core::mem::size_of::<T>())
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}
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/// Build an ioctl number for an write-only ioctl.
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#[inline(always)]
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pub const fn _IOW<T>(ty: u32, nr: u32) -> u32 {
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_IOC(uapi::_IOC_WRITE, ty, nr, core::mem::size_of::<T>())
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}
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/// Build an ioctl number for a read-write ioctl.
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#[inline(always)]
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pub const fn _IOWR<T>(ty: u32, nr: u32) -> u32 {
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_IOC(
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uapi::_IOC_READ | uapi::_IOC_WRITE,
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ty,
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nr,
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core::mem::size_of::<T>(),
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)
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}
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/// Get the ioctl direction from an ioctl number.
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pub const fn _IOC_DIR(nr: u32) -> u32 {
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(nr >> uapi::_IOC_DIRSHIFT) & uapi::_IOC_DIRMASK
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}
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/// Get the ioctl type from an ioctl number.
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pub const fn _IOC_TYPE(nr: u32) -> u32 {
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(nr >> uapi::_IOC_TYPESHIFT) & uapi::_IOC_TYPEMASK
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}
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/// Get the ioctl number from an ioctl number.
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pub const fn _IOC_NR(nr: u32) -> u32 {
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(nr >> uapi::_IOC_NRSHIFT) & uapi::_IOC_NRMASK
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}
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/// Get the ioctl size from an ioctl number.
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pub const fn _IOC_SIZE(nr: u32) -> usize {
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((nr >> uapi::_IOC_SIZESHIFT) & uapi::_IOC_SIZEMASK) as usize
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}
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