Add symbols for non-windows dll proxying

Signed-off-by: Dimitris Zervas <dzervas@dzervas.gr>

.gitignore

@@ -8,3 +8,4 @@ __handlers__
 /examples/cs/bin
 /examples/cs/obj
 /dotnet
+src/symbols.rs

build.rs

@@ -1,4 +1,7 @@
 use std::env;
+use std::io::Write;
+use std::fs::File;
+use std::path::Path;
 #[cfg(feature = "dotnet")]
 use csbindgen;
 
@@ -6,9 +9,12 @@ fn main() {
 	println!("cargo:rerun-if-env-changed=FRIDA_CODE");
 	println!("cargo:rerun-if-env-changed=DLL_PROXY");
 
-	if let Ok(lib_path) = env::var("DLL_PROXY") {
+	let Ok(lib_path) = env::var("DLL_PROXY") else {
-		println!("cargo:rerun-if-changed={}", &lib_path);
+		return;
+	};
+
 	use goblin::Object;
+	println!("cargo:rerun-if-changed={}", &lib_path);
 
 	let path = std::path::Path::new(&lib_path);
 	let lib_filename = path.file_name().unwrap().to_str().unwrap();
@@ -56,13 +62,24 @@ fn main() {
 	}
 
 	#[cfg(not(target_os = "windows"))]
+	{
+		let symbols_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("src").join("symbols.rs");
+		let mut symbols = File::create(&symbols_path).unwrap();
+		println!("cargo:rerun-if-changed={:?}", symbols_path);
+
+		writeln!(symbols, "#[allow(dead_code)]").unwrap();
+		writeln!(symbols, "#[link(name = \"{}\")]", lib_name.replace("lib", "")).unwrap();
+		writeln!(symbols, "extern {{").unwrap();
 		for e in exports.iter() {
 			println!("cargo:warning=Exported function: {}", e);
+			// writeln!(symbols, "\t#[no_mangle]").unwrap();
+			writeln!(symbols, "\tpub fn {}();", e).unwrap();
+		}
+		writeln!(symbols, "}}").unwrap();
 	}
 
 	println!("cargo:warning=Expected library name: {}-orig.dll", lib_name);
 	println!("cargo:rustc-env=LIB_NAME={}-orig.dll", lib_name);
-	}
 
 	#[cfg(feature = "dotnet")]
 	{

src/lib.rs

@@ -3,6 +3,8 @@ pub mod injector;
 pub mod frida_handler;
 // #[cfg(feature = "dotnet")]
 // pub mod cs;
+#[cfg(not(windows))]
+pub mod symbols;
 
 pub use injector::attach_self;