// 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, Kiocb}, ioctl::{_IO, _IOC_SIZE, _IOR, _IOW}, iov::{IovIterDest, IovIterSource}, miscdevice::{MiscDevice, MiscDeviceOptions, MiscDeviceRegistration}, new_mutex, prelude::*, sync::{aref::ARef, Mutex}, 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", authors: ["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, buffer: KVVec<u8>,} #[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, buffer: KVVec::new(), }), dev: dev, } }, GFP_KERNEL, ) } fn read_iter(mut kiocb: Kiocb<'_, Self::Ptr>, iov: &mut IovIterDest<'_>) -> Result<usize> { let me = kiocb.file(); dev_info!(me.dev, "Reading from Rust Misc Device Sample\n"); let inner = me.inner.lock(); // Read the buffer contents, taking the file position into account. let read = iov.simple_read_from_buffer(kiocb.ki_pos_mut(), &inner.buffer)?; Ok(read) } fn write_iter(mut kiocb: Kiocb<'_, Self::Ptr>, iov: &mut IovIterSource<'_>) -> Result<usize> { let me = kiocb.file(); dev_info!(me.dev, "Writing to Rust Misc Device Sample\n"); let mut inner = me.inner.lock(); // Replace buffer contents. inner.buffer.clear(); let len = iov.copy_from_iter_vec(&mut inner.buffer, GFP_KERNEL)?; // Set position to zero so that future `read` calls will see the new contents. *kiocb.ki_pos_mut() = 0; Ok(len) } fn ioctl(me: Pin<&RustMiscDevice>, _file: &File, cmd: u32, arg: usize) -> Result<isize> { dev_info!(me.dev, "IOCTLing Rust Misc Device Sample\n"); // Treat the ioctl argument as a user pointer. let arg = UserPtr::from_addr(arg); 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) }}
// 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, Kiocb},
ioctl::{_IO, _IOC_SIZE, _IOR, _IOW},
iov::{IovIterDest, IovIterSource},
miscdevice::{MiscDevice, MiscDeviceOptions, MiscDeviceRegistration},
new_mutex,
prelude::*,
sync::{aref::ARef, Mutex},
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",
authors: ["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,
buffer: KVVec<u8>,
}
#[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,
buffer: KVVec::new(),
}),
dev: dev,
}
},
GFP_KERNEL,
)
}
fn read_iter(mut kiocb: Kiocb<'_, Self::Ptr>, iov: &mut IovIterDest<'_>) -> Result<usize> {
let me = kiocb.file();
dev_info!(me.dev, "Reading from Rust Misc Device Sample\n");
let inner = me.inner.lock();
// Read the buffer contents, taking the file position into account.
let read = iov.simple_read_from_buffer(kiocb.ki_pos_mut(), &inner.buffer)?;
Ok(read)
}
fn write_iter(mut kiocb: Kiocb<'_, Self::Ptr>, iov: &mut IovIterSource<'_>) -> Result<usize> {
let me = kiocb.file();
dev_info!(me.dev, "Writing to Rust Misc Device Sample\n");
let mut inner = me.inner.lock();
// Replace buffer contents.
inner.buffer.clear();
let len = iov.copy_from_iter_vec(&mut inner.buffer, GFP_KERNEL)?;
// Set position to zero so that future `read` calls will see the new contents.
*kiocb.ki_pos_mut() = 0;
Ok(len)
}
fn ioctl(me: Pin<&RustMiscDevice>, _file: &File, cmd: u32, arg: usize) -> Result<isize> {
dev_info!(me.dev, "IOCTLing Rust Misc Device Sample\n");
// Treat the ioctl argument as a user pointer.
let arg = UserPtr::from_addr(arg);
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)
}
}