1//! Implements typical patterns for `ioctl` usage.
2
3use super::{Ioctl, IoctlOutput, Opcode, RawOpcode};
4
5use crate::backend::c;
6use crate::io::Result;
7
8use core::marker::PhantomData;
9use core::ptr::addr_of_mut;
10use core::{fmt, mem};
11
12/// Implements an `ioctl` with no real arguments.
13pub struct NoArg<Opcode> {
14 /// The opcode.
15 _opcode: PhantomData<Opcode>,
16}
17
18impl<Opcode: CompileTimeOpcode> fmt::Debug for NoArg<Opcode> {
19 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
20 f.debug_tuple(name:"NoArg").field(&Opcode::OPCODE).finish()
21 }
22}
23
24impl<Opcode: CompileTimeOpcode> NoArg<Opcode> {
25 /// Create a new no-argument `ioctl` object.
26 ///
27 /// # Safety
28 ///
29 /// - `Opcode` must provide a valid opcode.
30 #[inline]
31 pub unsafe fn new() -> Self {
32 Self {
33 _opcode: PhantomData,
34 }
35 }
36}
37
38unsafe impl<Opcode: CompileTimeOpcode> Ioctl for NoArg<Opcode> {
39 type Output = ();
40
41 const IS_MUTATING: bool = false;
42 const OPCODE: self::Opcode = Opcode::OPCODE;
43
44 fn as_ptr(&mut self) -> *mut c::c_void {
45 core::ptr::null_mut()
46 }
47
48 unsafe fn output_from_ptr(_: IoctlOutput, _: *mut c::c_void) -> Result<Self::Output> {
49 Ok(())
50 }
51}
52
53/// Implements the traditional “getter” pattern for `ioctl`s.
54///
55/// Some `ioctl`s just read data into the userspace. As this is a popular
56/// pattern this structure implements it.
57pub struct Getter<Opcode, Output> {
58 /// The output data.
59 output: mem::MaybeUninit<Output>,
60
61 /// The opcode.
62 _opcode: PhantomData<Opcode>,
63}
64
65impl<Opcode: CompileTimeOpcode, Output> fmt::Debug for Getter<Opcode, Output> {
66 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
67 f.debug_tuple(name:"Getter").field(&Opcode::OPCODE).finish()
68 }
69}
70
71impl<Opcode: CompileTimeOpcode, Output> Getter<Opcode, Output> {
72 /// Create a new getter-style `ioctl` object.
73 ///
74 /// # Safety
75 ///
76 /// - `Opcode` must provide a valid opcode.
77 /// - For this opcode, `Output` must be the type that the kernel expects to
78 /// write into.
79 #[inline]
80 pub unsafe fn new() -> Self {
81 Self {
82 output: mem::MaybeUninit::uninit(),
83 _opcode: PhantomData,
84 }
85 }
86}
87
88unsafe impl<Opcode: CompileTimeOpcode, Output> Ioctl for Getter<Opcode, Output> {
89 type Output = Output;
90
91 const IS_MUTATING: bool = true;
92 const OPCODE: self::Opcode = Opcode::OPCODE;
93
94 fn as_ptr(&mut self) -> *mut c::c_void {
95 self.output.as_mut_ptr().cast()
96 }
97
98 unsafe fn output_from_ptr(_: IoctlOutput, ptr: *mut c::c_void) -> Result<Self::Output> {
99 Ok(ptr.cast::<Output>().read())
100 }
101}
102
103/// Implements the pattern for `ioctl`s where a pointer argument is given to
104/// the `ioctl`.
105///
106/// The opcode must be read-only.
107pub struct Setter<Opcode, Input> {
108 /// The input data.
109 input: Input,
110
111 /// The opcode.
112 _opcode: PhantomData<Opcode>,
113}
114
115impl<Opcode: CompileTimeOpcode, Input: fmt::Debug> fmt::Debug for Setter<Opcode, Input> {
116 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
117 f&mut DebugTuple<'_, '_>.debug_tuple(name:"Setter")
118 .field(&Opcode::OPCODE)
119 .field(&self.input)
120 .finish()
121 }
122}
123
124impl<Opcode: CompileTimeOpcode, Input> Setter<Opcode, Input> {
125 /// Create a new pointer setter-style `ioctl` object.
126 ///
127 /// # Safety
128 ///
129 /// - `Opcode` must provide a valid opcode.
130 /// - For this opcode, `Input` must be the type that the kernel expects to
131 /// get.
132 #[inline]
133 pub unsafe fn new(input: Input) -> Self {
134 Self {
135 input,
136 _opcode: PhantomData,
137 }
138 }
139}
140
141unsafe impl<Opcode: CompileTimeOpcode, Input> Ioctl for Setter<Opcode, Input> {
142 type Output = ();
143
144 const IS_MUTATING: bool = false;
145 const OPCODE: self::Opcode = Opcode::OPCODE;
146
147 fn as_ptr(&mut self) -> *mut c::c_void {
148 addr_of_mut!(self.input).cast::<c::c_void>()
149 }
150
151 unsafe fn output_from_ptr(_: IoctlOutput, _: *mut c::c_void) -> Result<Self::Output> {
152 Ok(())
153 }
154}
155
156/// Implements an “updater” pattern for `ioctl`s.
157///
158/// The ioctl takes a reference to a struct that it reads its input from,
159/// then writes output to the same struct.
160pub struct Updater<'a, Opcode, Value> {
161 /// Reference to input/output data.
162 value: &'a mut Value,
163
164 /// The opcode.
165 _opcode: PhantomData<Opcode>,
166}
167
168impl<'a, Opcode: CompileTimeOpcode, Value> Updater<'a, Opcode, Value> {
169 /// Create a new pointer updater-style `ioctl` object.
170 ///
171 /// # Safety
172 ///
173 /// - `Opcode` must provide a valid opcode.
174 /// - For this opcode, `Value` must be the type that the kernel expects to
175 /// get.
176 #[inline]
177 pub unsafe fn new(value: &'a mut Value) -> Self {
178 Self {
179 value,
180 _opcode: PhantomData,
181 }
182 }
183}
184
185unsafe impl<'a, Opcode: CompileTimeOpcode, T> Ioctl for Updater<'a, Opcode, T> {
186 type Output = ();
187
188 const IS_MUTATING: bool = true;
189 const OPCODE: self::Opcode = Opcode::OPCODE;
190
191 fn as_ptr(&mut self) -> *mut c::c_void {
192 (self.value as *mut T).cast()
193 }
194
195 unsafe fn output_from_ptr(_output: IoctlOutput, _ptr: *mut c::c_void) -> Result<()> {
196 Ok(())
197 }
198}
199
200/// Implements an `ioctl` that passes an integer into the `ioctl`.
201pub struct IntegerSetter<Opcode> {
202 /// The value to pass in.
203 value: usize,
204
205 /// The opcode.
206 _opcode: PhantomData<Opcode>,
207}
208
209impl<Opcode: CompileTimeOpcode> IntegerSetter<Opcode> {
210 /// Create a new integer `Ioctl` helper.
211 ///
212 /// # Safety
213 ///
214 /// - `Opcode` must provide a valid opcode.
215 /// - For this opcode, it must expect an integer.
216 /// - The integer is in the valid range for this opcode.
217 #[inline]
218 pub unsafe fn new(value: usize) -> Self {
219 Self {
220 value,
221 _opcode: PhantomData,
222 }
223 }
224}
225
226unsafe impl<Opcode: CompileTimeOpcode> Ioctl for IntegerSetter<Opcode> {
227 type Output = ();
228
229 const IS_MUTATING: bool = false;
230 const OPCODE: self::Opcode = Opcode::OPCODE;
231
232 fn as_ptr(&mut self) -> *mut c::c_void {
233 // TODO: strict provenance
234 self.value as *mut c::c_void
235 }
236
237 unsafe fn output_from_ptr(
238 _out: IoctlOutput,
239 _extract_output: *mut c::c_void,
240 ) -> Result<Self::Output> {
241 Ok(())
242 }
243}
244
245/// Trait for something that provides an `ioctl` opcode at compile time.
246pub trait CompileTimeOpcode {
247 /// The opcode.
248 const OPCODE: Opcode;
249}
250
251/// Provides a bad opcode at compile time.
252pub struct BadOpcode<const OPCODE: RawOpcode>;
253
254impl<const OPCODE: RawOpcode> CompileTimeOpcode for BadOpcode<OPCODE> {
255 const OPCODE: Opcode = Opcode::old(OPCODE);
256}
257
258/// Provides a read code at compile time.
259///
260/// This corresponds to the C macro `_IOR(GROUP, NUM, Data)`.
261#[cfg(any(linux_kernel, bsd))]
262pub struct ReadOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
263
264#[cfg(any(linux_kernel, bsd))]
265impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for ReadOpcode<GROUP, NUM, Data> {
266 const OPCODE: Opcode = Opcode::read::<Data>(GROUP, NUM);
267}
268
269/// Provides a write code at compile time.
270///
271/// This corresponds to the C macro `_IOW(GROUP, NUM, Data)`.
272#[cfg(any(linux_kernel, bsd))]
273pub struct WriteOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
274
275#[cfg(any(linux_kernel, bsd))]
276impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for WriteOpcode<GROUP, NUM, Data> {
277 const OPCODE: Opcode = Opcode::write::<Data>(GROUP, NUM);
278}
279
280/// Provides a read/write code at compile time.
281///
282/// This corresponds to the C macro `_IOWR(GROUP, NUM, Data)`.
283#[cfg(any(linux_kernel, bsd))]
284pub struct ReadWriteOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
285
286#[cfg(any(linux_kernel, bsd))]
287impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for ReadWriteOpcode<GROUP, NUM, Data> {
288 const OPCODE: Opcode = Opcode::read_write::<Data>(GROUP, NUM);
289}
290
291/// Provides a `None` code at compile time.
292///
293/// This corresponds to the C macro `_IO(GROUP, NUM)` when `Data` is zero
294/// sized.
295#[cfg(any(linux_kernel, bsd))]
296pub struct NoneOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
297
298#[cfg(any(linux_kernel, bsd))]
299impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for NoneOpcode<GROUP, NUM, Data> {
300 const OPCODE: Opcode = Opcode::none::<Data>(GROUP, NUM);
301}
302