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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2025 Google LLC.
//! Sample DebugFS exporting platform driver that demonstrates the use of//! `Scope::dir` to create a variety of files without the need to separately//! track them all.
use kernel::{ debugfs::{ Dir, Scope, // }, new_mutex, prelude::*, sizes::*, str::CString, sync::{ atomic::Atomic, Mutex, // },};
module! { type: RustScopedDebugFs, name: "rust_debugfs_scoped", authors: ["Matthew Maurer"], description: "Rust Scoped DebugFS usage sample", license: "GPL",}
fn remove_file_write( mod_data: &ModuleData, reader: &mut kernel::uaccess::UserSliceReader,) -> Result { let mut buf = [0u8; 128]; if reader.len() >= buf.len() { return Err(EINVAL); } let n = reader.len(); reader.read_slice(&mut buf[..n])?;
let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?.trim(); let nul_idx = s.len(); buf[nul_idx] = 0; let to_remove = CStr::from_bytes_with_nul(&buf[..nul_idx + 1]).map_err(|_| EINVAL)?; mod_data .devices .lock() .retain(|device| device.name.to_bytes() != to_remove.to_bytes()); Ok(())}
fn create_file_write( mod_data: &ModuleData, reader: &mut kernel::uaccess::UserSliceReader,) -> Result { let mut buf = [0u8; 128]; if reader.len() > buf.len() { return Err(EINVAL); } let n = reader.len(); reader.read_slice(&mut buf[..n])?;
let mut nums = KVec::new();
let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?.trim(); let mut items = s.split_whitespace(); let name_str = items.next().ok_or(EINVAL)?; let name = CString::try_from_fmt(fmt!("{name_str}"))?; let file_name = CString::try_from_fmt(fmt!("{name_str}"))?; for sub in items { nums.push( Atomic::<usize>::new(sub.parse().map_err(|_| EINVAL)?), GFP_KERNEL, )?; } let blob = KBox::pin_init(new_mutex!([0x42; SZ_4K]), GFP_KERNEL)?;
let scope = KBox::pin_init( mod_data.device_dir.scope( DeviceData { name, nums, blob }, &file_name, |dev_data, dir| { for (idx, val) in dev_data.nums.iter().enumerate() { let Ok(name) = CString::try_from_fmt(fmt!("{idx}")) else { return; }; dir.read_write_file(&name, val); } dir.read_write_binary_file(c"blob", &dev_data.blob); }, ), GFP_KERNEL, )?; (*mod_data.devices.lock()).push(scope, GFP_KERNEL)?;
Ok(())}
struct RustScopedDebugFs { _data: Pin<KBox<Scope<ModuleData>>>,}
#[pin_data]struct ModuleData { device_dir: Dir, #[pin] devices: Mutex<KVec<Pin<KBox<Scope<DeviceData>>>>>,}
impl ModuleData { fn init(device_dir: Dir) -> impl PinInit<Self> { pin_init! { Self { device_dir: device_dir, devices <- new_mutex!(KVec::new()) } } }}
struct DeviceData { name: CString, nums: KVec<Atomic<usize>>, blob: Pin<KBox<Mutex<[u8; SZ_4K]>>>,}
fn init_control(base_dir: &Dir, dyn_dirs: Dir) -> impl PinInit<Scope<ModuleData>> + '_ { base_dir.scope(ModuleData::init(dyn_dirs), c"control", |data, dir| { dir.write_only_callback_file(c"create", data, &create_file_write); dir.write_only_callback_file(c"remove", data, &remove_file_write); })}
impl kernel::Module for RustScopedDebugFs { fn init(_module: &'static kernel::ThisModule) -> Result<Self> { let base_dir = Dir::new(c"rust_scoped_debugfs"); let dyn_dirs = base_dir.subdir(c"dynamic"); Ok(Self { _data: KBox::pin_init(init_control(&base_dir, dyn_dirs), GFP_KERNEL)?, }) }}