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Commit 4d40ebbf authored by Michael Sun's avatar Michael Sun
Browse files

floss: avrcp: introduce uinput library for Floss AVRCP 

Introduce a custom uinput library to support Floss AVRCP functionality.
The library will help Floss media interface to create and own a uinput
device to propagate received AVRCP commands as uinput events.

Bug: 240780817
Tag: #floss
Test: verified locally that valid fd can be acquired

Change-Id: I704acc53231ccedac43872afd21decc30a66b65c
parent e5b6a86e

system/gd/rust/linux/utils/src/lib.rs

+1 −0
Original line number Diff line number Diff line
@@ -4,3 +4,4 @@ 
extern crate num_derive;



pub mod socket;

pub mod uinput;

system/gd/rust/linux/utils/src/uinput.rs

0 → 100644
+101 −0
Original line number Diff line number Diff line 
//! This library provides access to Linux uinput.



use libc;

use log::error;

use std::ffi::CString;



// uinput setup constants

const UINPUT_MAX_NAME_SIZE: usize = 80;

const ABS_MAX: usize = 0x3F;

const BUS_BLUETOOTH: u16 = 0x05;



#[repr(C, packed)]

struct UInputId {

    bustype: libc::c_ushort,

    vendor: libc::c_ushort,

    product: libc::c_ushort,

    version: libc::c_ushort,

}



#[repr(C, packed)]

struct UInputDev {

    name: [libc::c_char; UINPUT_MAX_NAME_SIZE],

    id: UInputId,

    ff_effects_max: libc::c_int,

    absmax: [libc::c_int; ABS_MAX + 1],

    absmin: [libc::c_int; ABS_MAX + 1],

    absfuzz: [libc::c_int; ABS_MAX + 1],

    absflat: [libc::c_int; ABS_MAX + 1],

}



/// A struct that holds the uinput object. It consists of a file descriptor fetched from the kernel

/// and a device struct which contains the information required to construct an uinput device.

#[allow(dead_code)]

pub struct UInput {

    fd: i32,

    device: UInputDev,

}



impl Drop for UInput {

    fn drop(&mut self) {

        self.close();

    }

}



impl UInput {

    /// Create a new UInput object.

    pub fn new() -> Self {

        UInput {

            fd: -1,

            device: UInputDev {

                name: [0; UINPUT_MAX_NAME_SIZE],

                id: UInputId { bustype: BUS_BLUETOOTH, vendor: 0, product: 0, version: 0 },

                ff_effects_max: 0,

                absmax: [0; ABS_MAX + 1],

                absmin: [0; ABS_MAX + 1],

                absfuzz: [0; ABS_MAX + 1],

                absflat: [0; ABS_MAX + 1],

            },

        }

    }



    /// Return true if uinput is open and a valid fd is retrieved.

    pub fn is_initialized(&self) -> bool {

        self.fd >= 0

    }



    /// Initialize a uinput device with kernel.

    #[allow(temporary_cstring_as_ptr)]

    pub fn init(&mut self) {

        if self.is_initialized() {

            return;

        }



        let mut fd = -1;



        unsafe {

            for path in ["/dev/uinput", "/dev/input/uinput", "/dev/misc/uinput"] {

                fd = libc::open(CString::new(path).unwrap().as_ptr().cast(), libc::O_RDWR);

                if fd >= 0 {

                    break;

                }

            }

        }



        if fd < -1 {

            error!("Failed to open uinput");

            return;

        }

        self.fd = fd;

    }



    /// Close the uinput device with kernel if there is one.

    pub fn close(&mut self) {

        if self.is_initialized() {

            unsafe {

                libc::close(self.fd);

            }

            self.fd = -1;

        }

    }

}