mirror of https://github.com/torvalds/linux.git
84 lines
2.7 KiB
Rust
84 lines
2.7 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2025 Google LLC.
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//! Traits for rendering or updating values exported to DebugFS.
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use crate::prelude::*;
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use crate::sync::atomic::{Atomic, AtomicBasicOps, AtomicType, Relaxed};
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use crate::sync::Mutex;
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use crate::uaccess::UserSliceReader;
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use core::fmt::{self, Debug, Formatter};
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use core::str::FromStr;
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/// A trait for types that can be written into a string.
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///
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/// This works very similarly to `Debug`, and is automatically implemented if `Debug` is
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/// implemented for a type. It is also implemented for any writable type inside a `Mutex`.
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///
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/// The derived implementation of `Debug` [may
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/// change](https://doc.rust-lang.org/std/fmt/trait.Debug.html#stability)
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/// between Rust versions, so if stability is key for your use case, please implement `Writer`
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/// explicitly instead.
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pub trait Writer {
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/// Formats the value using the given formatter.
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fn write(&self, f: &mut Formatter<'_>) -> fmt::Result;
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}
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impl<T: Writer> Writer for Mutex<T> {
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fn write(&self, f: &mut Formatter<'_>) -> fmt::Result {
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self.lock().write(f)
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}
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}
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impl<T: Debug> Writer for T {
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fn write(&self, f: &mut Formatter<'_>) -> fmt::Result {
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writeln!(f, "{self:?}")
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}
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}
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/// A trait for types that can be updated from a user slice.
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///
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/// This works similarly to `FromStr`, but operates on a `UserSliceReader` rather than a &str.
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///
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/// It is automatically implemented for all atomic integers, or any type that implements `FromStr`
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/// wrapped in a `Mutex`.
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pub trait Reader {
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/// Updates the value from the given user slice.
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fn read_from_slice(&self, reader: &mut UserSliceReader) -> Result;
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}
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impl<T: FromStr + Unpin> Reader for Mutex<T> {
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fn read_from_slice(&self, reader: &mut UserSliceReader) -> Result {
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let mut buf = [0u8; 128];
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if reader.len() > buf.len() {
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return Err(EINVAL);
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}
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let n = reader.len();
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reader.read_slice(&mut buf[..n])?;
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let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?;
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let val = s.trim().parse::<T>().map_err(|_| EINVAL)?;
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*self.lock() = val;
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Ok(())
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}
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}
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impl<T: AtomicType + FromStr> Reader for Atomic<T>
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where
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T::Repr: AtomicBasicOps,
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{
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fn read_from_slice(&self, reader: &mut UserSliceReader) -> Result {
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let mut buf = [0u8; 21]; // Enough for a 64-bit number.
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if reader.len() > buf.len() {
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return Err(EINVAL);
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}
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let n = reader.len();
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reader.read_slice(&mut buf[..n])?;
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let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?;
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let val = s.trim().parse::<T>().map_err(|_| EINVAL)?;
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self.store(val, Relaxed);
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Ok(())
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}
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}
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