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|
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2024 Google LLC.
//! Rust misc device sample.
/// Below is an example userspace C program that exercises this sample's functionality.
///
/// ```c
/// #include <stdio.h>
/// #include <stdlib.h>
/// #include <errno.h>
/// #include <fcntl.h>
/// #include <unistd.h>
/// #include <sys/ioctl.h>
///
/// #define RUST_MISC_DEV_FAIL _IO('|', 0)
/// #define RUST_MISC_DEV_HELLO _IO('|', 0x80)
/// #define RUST_MISC_DEV_GET_VALUE _IOR('|', 0x81, int)
/// #define RUST_MISC_DEV_SET_VALUE _IOW('|', 0x82, int)
///
/// int main() {
/// int value, new_value;
/// int fd, ret;
///
/// // Open the device file
/// printf("Opening /dev/rust-misc-device for reading and writing\n");
/// fd = open("/dev/rust-misc-device", O_RDWR);
/// if (fd < 0) {
/// perror("open");
/// return errno;
/// }
///
/// // Make call into driver to say "hello"
/// printf("Calling Hello\n");
/// ret = ioctl(fd, RUST_MISC_DEV_HELLO, NULL);
/// if (ret < 0) {
/// perror("ioctl: Failed to call into Hello");
/// close(fd);
/// return errno;
/// }
///
/// // Get initial value
/// printf("Fetching initial value\n");
/// ret = ioctl(fd, RUST_MISC_DEV_GET_VALUE, &value);
/// if (ret < 0) {
/// perror("ioctl: Failed to fetch the initial value");
/// close(fd);
/// return errno;
/// }
///
/// value++;
///
/// // Set value to something different
/// printf("Submitting new value (%d)\n", value);
/// ret = ioctl(fd, RUST_MISC_DEV_SET_VALUE, &value);
/// if (ret < 0) {
/// perror("ioctl: Failed to submit new value");
/// close(fd);
/// return errno;
/// }
///
/// // Ensure new value was applied
/// printf("Fetching new value\n");
/// ret = ioctl(fd, RUST_MISC_DEV_GET_VALUE, &new_value);
/// if (ret < 0) {
/// perror("ioctl: Failed to fetch the new value");
/// close(fd);
/// return errno;
/// }
///
/// if (value != new_value) {
/// printf("Failed: Committed and retrieved values are different (%d - %d)\n", value, new_value);
/// close(fd);
/// return -1;
/// }
///
/// // Call the unsuccessful ioctl
/// printf("Attempting to call in to an non-existent IOCTL\n");
/// ret = ioctl(fd, RUST_MISC_DEV_FAIL, NULL);
/// if (ret < 0) {
/// perror("ioctl: Succeeded to fail - this was expected");
/// } else {
/// printf("ioctl: Failed to fail\n");
/// close(fd);
/// return -1;
/// }
///
/// // Close the device file
/// printf("Closing /dev/rust-misc-device\n");
/// close(fd);
///
/// printf("Success\n");
/// return 0;
/// }
/// ```
use core::pin::Pin;
use kernel::{
c_str,
device::Device,
fs::File,
ioctl::{_IO, _IOC_SIZE, _IOR, _IOW},
miscdevice::{MiscDevice, MiscDeviceOptions, MiscDeviceRegistration},
new_mutex,
prelude::*,
sync::Mutex,
types::ARef,
uaccess::{UserSlice, UserSliceReader, UserSliceWriter},
};
const RUST_MISC_DEV_HELLO: u32 = _IO('|' as u32, 0x80);
const RUST_MISC_DEV_GET_VALUE: u32 = _IOR::<i32>('|' as u32, 0x81);
const RUST_MISC_DEV_SET_VALUE: u32 = _IOW::<i32>('|' as u32, 0x82);
module! {
type: RustMiscDeviceModule,
name: "rust_misc_device",
author: "Lee Jones",
description: "Rust misc device sample",
license: "GPL",
}
#[pin_data]
struct RustMiscDeviceModule {
#[pin]
_miscdev: MiscDeviceRegistration<RustMiscDevice>,
}
impl kernel::InPlaceModule for RustMiscDeviceModule {
fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
pr_info!("Initialising Rust Misc Device Sample\n");
let options = MiscDeviceOptions {
name: c_str!("rust-misc-device"),
};
try_pin_init!(Self {
_miscdev <- MiscDeviceRegistration::register(options),
})
}
}
struct Inner {
value: i32,
}
#[pin_data(PinnedDrop)]
struct RustMiscDevice {
#[pin]
inner: Mutex<Inner>,
dev: ARef<Device>,
}
#[vtable]
impl MiscDevice for RustMiscDevice {
type Ptr = Pin<KBox<Self>>;
fn open(_file: &File, misc: &MiscDeviceRegistration<Self>) -> Result<Pin<KBox<Self>>> {
let dev = ARef::from(misc.device());
dev_info!(dev, "Opening Rust Misc Device Sample\n");
KBox::try_pin_init(
try_pin_init! {
RustMiscDevice {
inner <- new_mutex!( Inner{ value: 0_i32 } ),
dev: dev,
}
},
GFP_KERNEL,
)
}
fn ioctl(me: Pin<&RustMiscDevice>, _file: &File, cmd: u32, arg: usize) -> Result<isize> {
dev_info!(me.dev, "IOCTLing Rust Misc Device Sample\n");
let size = _IOC_SIZE(cmd);
match cmd {
RUST_MISC_DEV_GET_VALUE => me.get_value(UserSlice::new(arg, size).writer())?,
RUST_MISC_DEV_SET_VALUE => me.set_value(UserSlice::new(arg, size).reader())?,
RUST_MISC_DEV_HELLO => me.hello()?,
_ => {
dev_err!(me.dev, "-> IOCTL not recognised: {}\n", cmd);
return Err(ENOTTY);
}
};
Ok(0)
}
}
#[pinned_drop]
impl PinnedDrop for RustMiscDevice {
fn drop(self: Pin<&mut Self>) {
dev_info!(self.dev, "Exiting the Rust Misc Device Sample\n");
}
}
impl RustMiscDevice {
fn set_value(&self, mut reader: UserSliceReader) -> Result<isize> {
let new_value = reader.read::<i32>()?;
let mut guard = self.inner.lock();
dev_info!(
self.dev,
"-> Copying data from userspace (value: {})\n",
new_value
);
guard.value = new_value;
Ok(0)
}
fn get_value(&self, mut writer: UserSliceWriter) -> Result<isize> {
let guard = self.inner.lock();
let value = guard.value;
// Free-up the lock and use our locally cached instance from here
drop(guard);
dev_info!(
self.dev,
"-> Copying data to userspace (value: {})\n",
&value
);
writer.write::<i32>(&value)?;
Ok(0)
}
fn hello(&self) -> Result<isize> {
dev_info!(self.dev, "-> Hello from the Rust Misc Device\n");
Ok(0)
}
}
|
