libafl_nyx: Build qemu/packer in target directory

crates/libafl_nyx/build.rs

@@ -1,10 +1,23 @@
-use std::process::Command;
-
+use std::{env, path::PathBuf, process::Command};
 fn main() {
     if cfg!(target_os = "linux") && cfg!(target_arch = "x86_64") && !cfg!(doc) {
+        // Use CARGO_TARGET_DIR if available, otherwise fall back to OUT_DIR's parent directories
+        let target_dir = if let Ok(target_dir) = env::var("CARGO_TARGET_DIR") {
+            PathBuf::from(target_dir)
+        } else {
+            // OUT_DIR is usually $TARGET/{debug|release}/build/$PKG-$HASH/out
+            // We want $TARGET/{debug|release}
+            let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+            out_dir
+                .ancestors()
+                .nth(3) // This is still a fallback, but at least we try CARGO_TARGET_DIR first
+                .map(std::path::Path::to_path_buf)
+                .expect("Failed to determine target directory from OUT_DIR")
+        };
         println!("cargo:rerun-if-changed=build.rs");
         // let output = Command::new("./build_nyx_support.sh").output().expect("can't run ./build_nyx_support.sh");
         let status = Command::new("./build_nyx_support.sh")
+            .arg(target_dir)
             .status()
             .expect("can't run ./build_nyx_support.sh");
         if status.success() {

crates/libafl_nyx/build_nyx_support.sh

@@ -1,7 +1,16 @@
 #!/bin/bash
 
+if [ -z "$1" ]; then
+    echo "Usage: $0 <target-directory>"
+    exit 1
+fi
+
 SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 
+TARGET_DIR="$1"
+mkdir -p "$TARGET_DIR"
+cd "$TARGET_DIR" || exit 1
+
 echo "================================================="
 echo "           Nyx build script"
 echo "================================================="
@@ -44,8 +53,8 @@ echo "[*] Checking QEMU-Nyx ..."
 if [ ! -f "QEMU-Nyx/x86_64-softmmu/qemu-system-x86_64" ]; then
     cd QEMU-Nyx/ || return
     # We need to copy our custom `Makefile.libxdc` after `git submodule update`, otherwise we get a git error.
-    sed -i "s,git submodule update libxdc$,git submodule update libxdc \&\& cp ../Makefile.libxdc ./libxdc/Makefile || exit 1," compile_qemu_nyx.sh
-    ./compile_qemu_nyx.sh lto || exit 1
+    sed -i "s,git submodule update libxdc$,git submodule update libxdc \&\& cp \"\$SCRIPT_DIR\"/Makefile.libxdc ./libxdc/Makefile || exit 1," compile_qemu_nyx.sh
+    ./compile_qemu_nyx.sh lto
     cd ..
 fi
 

fuzzers/full_system/nyx_libxml2_parallel/setup_libxml2.sh

@@ -26,7 +26,7 @@ cd ./libxml2/ || exit
 ./autogen.sh --enable-shared=no || exit
 make -j || exit
 cd - || exit
-python3 "../../../crates/libafl_nyx/packer/packer/nyx_packer.py" \
+python3 "./target/release/packer/packer/nyx_packer.py" \
     ./libxml2/xmllint \
     /tmp/nyx_libxml2 \
     afl \

fuzzers/full_system/nyx_libxml2_standalone/setup_libxml2.sh

@@ -26,7 +26,7 @@ cd ./libxml2/ || exit
 ./autogen.sh --enable-shared=no || exit
 make -j || exit
 cd - || exit
-python3 "../../../crates/libafl_nyx/packer/packer/nyx_packer.py" \
+python3 "./target/release/packer/packer/nyx_packer.py" \
     ./libxml2/xmllint \
     /tmp/nyx_libxml2 \
     afl \