Capture OutputDebugString in Windows and emits the result to either the log (if enabled) or via println

ods_capture.rs

use std::ffi::c_void;
use std::slice;
use log::{info, log_enabled, Level};
use windows::core::s;
use windows::Win32::Foundation::{FALSE, HANDLE, INVALID_HANDLE_VALUE};
use windows::Win32::System::Diagnostics::Debug::IsDebuggerPresent;
use windows::Win32::System::Memory::{CreateFileMappingA, MapViewOfFile, FILE_MAP_READ, PAGE_READWRITE, SECTION_MAP_READ};
use windows::Win32::System::Threading::{CreateEventA, CreateEventW, CreateThread, SetEvent, WaitForSingleObject, INFINITE, THREAD_CREATE_RUN_IMMEDIATELY, THREAD_CREATION_FLAGS, GetCurrentProcessId};

#[repr(C)]
struct OdsBuffer {
    process_id: u32,
    data: [u8; 4092],
}

unsafe extern "system" fn ods_proc(args: *mut c_void) -> u32 {
    let file = CreateFileMappingA(INVALID_HANDLE_VALUE, None, PAGE_READWRITE, 0, size_of::<OdsBuffer>() as u32, s!("DBWIN_BUFFER")).unwrap();
    let ods_buffer = MapViewOfFile(file, FILE_MAP_READ, 0, 0, 0);
    let ods_buffer = ods_buffer.Value as *const OdsBuffer;
    let ods_buffer_ready = CreateEventA(None, false, false, s!("DBWIN_BUFFER_READY")).unwrap();
    let ods_data_ready = CreateEventA(None, false, false, s!("DBWIN_DATA_READY")).unwrap();

    loop {
        SetEvent(ods_buffer_ready).unwrap();
        let wait = WaitForSingleObject(ods_data_ready, INFINITE);

        let mut length: usize = 0;
        while length < 4092 && (*ods_buffer).data[length] != 0 {
            length += 1;
        }

        if length != 0 && (*ods_buffer).process_id == GetCurrentProcessId() {
            let data: &[u8] = slice::from_raw_parts(&(*ods_buffer).data[0], length);
            let str = std::str::from_utf8(data).unwrap().trim();
            if log_enabled!(Level::Info) {
                info!("{}", str);
            } else {
                println!("{}", str);
            }
        }
    }
}

pub fn ods_capture() {
    unsafe {
        let thread = CreateThread(None, 0, Some(ods_proc), None, THREAD_CREATE_RUN_IMMEDIATELY, None).unwrap();
   }
}