libafl_qemu 0.12.0

QEMU user backend library for LibAFL
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use std::{env, fs, path::{Path, PathBuf}, process::Command};

#[allow(clippy::too_many_lines)]
pub fn build() {
    // Note: Unique features are checked in libafl_qemu_sys

    let emulation_mode = if cfg!(feature = "usermode") {
        "usermode".to_string()
    } else if cfg!(feature = "systemmode") {
        "systemmode".to_string()
    } else {
        env::var("EMULATION_MODE").unwrap_or_else(|_| {
            "usermode".to_string()
        })
    };


    let qemu_asan_guest = cfg!(all(feature = "build_libgasan", not(feature = "hexagon")));
    let qemu_asan = cfg!(all(feature = "build_libqasan", not(feature = "hexagon")));

    let libafl_qemu_hdr_name = "libafl_qemu.h";

    let exit_hdr_dir = PathBuf::from("runtime");
    let libafl_qemu_hdr = exit_hdr_dir.join(libafl_qemu_hdr_name);

    println!("cargo:rustc-cfg=emulation_mode=\"{emulation_mode}\"");
    println!("cargo:rerun-if-env-changed=EMULATION_MODE");

    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-changed=build_linux.rs");
    println!("cargo:rerun-if-changed={}", exit_hdr_dir.display());

    let cpu_target = if cfg!(feature = "x86_64") {
        "x86_64".to_string()
    } else if cfg!(feature = "arm") {
        "arm".to_string()
    } else if cfg!(feature = "aarch64") {
        "aarch64".to_string()
    } else if cfg!(feature = "i386") {
        "i386".to_string()
    } else if cfg!(feature = "mips") {
        "mips".to_string()
    } else if cfg!(feature = "ppc") {
        "ppc".to_string()
    } else if cfg!(feature = "hexagon") {
        "hexagon".to_string()
    } else {
        env::var("CPU_TARGET").unwrap_or_else(|_| {
            "x86_64".to_string()
        })
    };
    println!("cargo:rerun-if-env-changed=CPU_TARGET");
    println!("cargo:rustc-cfg=cpu_target=\"{cpu_target}\"");

    let cross_cc = if (emulation_mode == "usermode") && (qemu_asan || qemu_asan_guest) {
        // TODO try to autodetect a cross compiler with the arch name (e.g. aarch64-linux-gnu-gcc)
        let cross_cc = env::var("CROSS_CC").unwrap_or_else(|_| {
            println!("cargo:warning=CROSS_CC is not set, default to cc (things can go wrong if the selected cpu target ({cpu_target}) is not the host arch ({}))", env::consts::ARCH);
            "cc".to_owned()
        });
        println!("cargo:rerun-if-env-changed=CROSS_CC");

        cross_cc
    } else {
        String::new()
    };

    if std::env::var("DOCS_RS").is_ok() {
        return; // only build when we're not generating docs
    }

    let out_dir = env::var("OUT_DIR").unwrap();
    let out_dir_path = Path::new(&out_dir);
    let out_dir_path_buf = out_dir_path.to_path_buf();
    let mut target_dir = out_dir_path_buf.clone();
    target_dir.pop();
    target_dir.pop();
    target_dir.pop();
    let include_dir = target_dir.join("include");

    fs::create_dir_all(&include_dir).expect("Could not create include dir");

    fs::copy(libafl_qemu_hdr.clone(), include_dir.join(libafl_qemu_hdr_name)).expect("Could not copy libafl_qemu.h to out directory.");

    let binding_file = out_dir_path_buf.join("backdoor_bindings.rs");
    bindgen::Builder::default()
        .derive_debug(true)
        .derive_default(true)
        .impl_debug(true)
        .generate_comments(true)
        .default_enum_style(bindgen::EnumVariation::NewType {
            is_global: true,
            is_bitfield: true,
        })
        .header(libafl_qemu_hdr.display().to_string())
        .generate()
        .expect("Exit bindings generation failed.")
        .write_to_file(binding_file)
        .expect("Could not write bindings.");

    if (emulation_mode == "usermode") && (qemu_asan || qemu_asan_guest) {
        let qasan_dir = Path::new("libqasan");
        let qasan_dir = fs::canonicalize(qasan_dir).unwrap();
        println!("cargo:rerun-if-changed={}", qasan_dir.display());

        let mut make = Command::new("make");
        if cfg!(debug_assertions) {
            make.env("CFLAGS", "-DDEBUG=1");
        }
        assert!(make
            .current_dir(out_dir_path)
            .env("CC", &cross_cc)
            .env("OUT_DIR", &target_dir)
            .arg("-C")
            .arg(&qasan_dir)
            .status()
            .expect("make failed")
            .success());
    }
}