/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at
https://mozilla.org/MPL/2.0/. */
use std::{ffi::CString, mem::size_of};
use error::ReadError;
pub mod error;
mod platform;
#[cfg(target_os = "windows")]
pub type ProcessHandle = windows_sys::Win32::Foundation::HANDLE;
#[cfg(any(target_os = "linux", target_os = "android"))]
pub type ProcessHandle = libc::pid_t;
#[cfg(any(target_os = "macos"))]
pub type ProcessHandle = mach2::mach_types::task_t;
pub struct ProcessReader {
process: ProcessHandle,
}
impl ProcessReader {
pub fn copy_null_terminated_string(&self, address: usize) -> Result<CString, ReadError> {
// Try copying the string word-by-word first, this is considerably
// faster than one byte at a time.
if let Ok(string) = self.copy_null_terminated_string_word_by_word(address) {
return Ok(string);
}
// Reading the string one word at a time failed, let's try again one
// byte at a time. It's slow but it might work in situations where the
// string alignment causes word-by-word access to straddle page
// boundaries.
let mut length = 0;
let mut string = Vec::<u8>::new();
loop {
let char = self.copy_object::<u8>(address + length)?;
length += 1;
string.push(char);
if char == 0 {
break;
}
}
// SAFETY: If we reach this point we've read at least one byte and we
// know that the last one we read is nul.
Ok(unsafe { CString::from_vec_with_nul_unchecked(string) })
}
fn copy_null_terminated_string_word_by_word(
&self,
address: usize,
) -> Result<CString, ReadError> {
const WORD_SIZE: usize = size_of::<usize>();
let mut length = 0;
let mut string = Vec::<u8>::new();
loop {
let array = self.copy_array::<u8>(address + length, WORD_SIZE)?;
let null_terminator = array.iter().position(|&e| e == 0);
length += null_terminator.unwrap_or(WORD_SIZE);
string.extend(array.into_iter());
if null_terminator.is_some() {
string.truncate(length + 1);
break;
}
}
// SAFETY: If we reach this point we've read at least one byte and we
// know that the last one we read is nul.
Ok(unsafe { CString::from_vec_with_nul_unchecked(string) })
}
}
