dlopen-rs

A versatile Rust library designed for loading ELF dynamic libraries from memory or from files.

This library serves three purposes:

1. Provide a pure Rust alternative to musl ld.so or glibc ld.so.
2. Provide loading ELF dynamic libraries support for #![no_std] targets.
3. Easily swap out symbols in shared libraries with your own custom symbols at runtime

Additional, it integrates seamlessly with the system’s dynamic linker in std environments when the ldso feature is enabled. Currently, it supports x86_64, x86, RV64, and AArch64 architectures.

Feature

Example

use dlopen_rs::ELFLibrary;
use nix::libc::size_t;
use std::{ffi::c_void, path::Path};

extern "C" fn mymalloc(size: size_t) -> *mut c_void {
    println!("malloc:{}bytes", size);
    unsafe { nix::libc::malloc(size) }
}

fn main() {
    let path = Path::new("./target/release/libexample.so");
    let libc = ELFLibrary::sys_load("libc.so.6").unwrap();
    let libgcc = ELFLibrary::sys_load("libgcc_s.so.1").unwrap();
    let libexample = ELFLibrary::from_file(path)
        .unwrap()
        .relocate_with_func(&[libc, libgcc], |name| {
            if name == "malloc" {
                return Some(mymalloc as _);
            } else {
                return None;
            }
        })
        .unwrap();
    let f = unsafe {
        libexample
            .get::<extern "C" fn(i32) -> i32>("c_fun_add_two")
            .unwrap()
    };
    println!("{}", f(2));

    let f = unsafe {
        libexample
            .get::<extern "C" fn()>("c_fun_print_something_else")
            .unwrap()
    };
    f();
}

NOTE

If you encounter any issues while using it or need any new features, feel free to raise an issue on GitHub. https://github.com/weizhiao/dlopen-rs