fix void function return handling

patcher/.gitignore

@@ -1 +1,2 @@
 target
+tests

patcher/Cargo.toml

@@ -6,8 +6,8 @@ edition = "2024"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-#androscalpel = { git = "ssh://git@gitlab.inria.fr/androidoftheseus/androscalpel.git", rev = "110f0c0", features = ["code-analysis", "platform-list"] }
+#androscalpel = { git = "ssh://git@gitlab.inria.fr/androidoftheseus/androscalpel.git", rev = "3a0b9bb", features = ["code-analysis", "platform-list"] }
-#apk_frauder = { git = "ssh://git@gitlab.inria.fr/androidoftheseus/androscalpel.git", rev = "110f0c0"}
+#apk_frauder = { git = "ssh://git@gitlab.inria.fr/androidoftheseus/androscalpel.git", rev = "3a0b9bb"}
 androscalpel = { path = "../../androscalpel/androscalpel", features = ["code-analysis", "platform-list"] }
 apk_frauder = { path = "../../androscalpel/apk_frauder"}
 anyhow = { version = "1.0.95", features = ["backtrace"] }

patcher/src/bin/patcher.rs

@@ -43,6 +43,7 @@ fn main() {
     env_logger::init();
     let cli = Cli::parse();
     let mut apk = Apk::load_apk(File::open(&cli.path).unwrap(), labeling, false).unwrap();
+
     //println!("{:#?}", apk.list_classes());
     let mut json = String::new();
     File::open(&cli.runtime_data)
@@ -107,19 +108,9 @@ fn main() {
         .into_values()
         .map(|v| (v.descriptor.clone(), v))
         .collect();
-    // Add the new testing class in a separateed dex file to avoid breaking
+    apk.add_class("classes.dex", class).unwrap();
-    // the dex method limit.
+    apk.redistribute_classes();
-    // TODO: check the number of methods in the existing dex files to avoid generated
+
-    //   a new one each time.
-    let mut i = 2;
-    let new_dex_name = loop {
-        let name = format!("classes{}.dex", i);
-        if !apk.dex_files.contains_key(&name) {
-            break name;
-        };
-        i += 1;
-    };
-    apk.add_class(&new_dex_name, class).unwrap();
     let mut dex_files = vec![];
     let mut files = apk.gen_raw_dex().unwrap();
     let mut i = 0;

patcher/src/reflection_patcher.rs

@@ -1346,7 +1346,7 @@ fn get_invoke_block(
         arg_arr,
         reg_inf.first_arg + if ref_data.is_static { 0 } else { 1 },
         reg_inf,
-    ));
+    )?);
     if ref_data.is_static {
         insns.push(Instruction::InvokeStatic {
             method: ref_data.get_static_callee(),
@@ -1375,7 +1375,7 @@ fn get_invoke_block(
                 to: reg_inf.array_val,
             });
             insns.push(Instruction::InvokeStatic {
-                method: get_scalar_to_obj_method(&ret_ty).unwrap(),
+                method: get_scalar_to_obj_method(&ret_ty)?,
                 args: vec![reg_inf.array_val as u16, (reg_inf.array_val + 1) as u16],
             });
             insns.push(move_result);
@@ -1383,12 +1383,19 @@ fn get_invoke_block(
                 reg: res_reg,
                 lit: OBJECT_TY.clone(),
             });
+        } else if ret_ty.is_void() {
+            // Void is represented by a null object
+            insns.push(Instruction::Const {
+                reg: res_reg,
+                lit: 0,
+            });
+            insns.push(move_result);
         } else {
             insns.push(Instruction::MoveResult {
                 to: reg_inf.array_val,
             });
             insns.push(Instruction::InvokeStatic {
-                method: get_scalar_to_obj_method(&ret_ty).unwrap(),
+                method: get_scalar_to_obj_method(&ret_ty)?,
                 args: vec![reg_inf.array_val as u16],
             });
             insns.push(move_result);
@@ -1415,7 +1422,7 @@ fn get_args_from_obj_arr(
     array_reg: u16,
     first_arg_reg: u16,
     reg_inf: &mut RegistersInfo,
-) -> Vec<Instruction> {
+) -> Result<Vec<Instruction>> {
     let mut insns = vec![];
     let mut restore_array = vec![];
     let mut reg_count = 0;
@@ -1455,10 +1462,10 @@ fn get_args_from_obj_arr(
         } else if param.is_double() || param.is_long() {
             insns.push(Instruction::CheckCast {
                 reg: reg_inf.array_val,
-                lit: get_obj_of_scalar(param).unwrap(),
+                lit: get_obj_of_scalar(param)?,
             });
             insns.push(Instruction::InvokeVirtual {
-                method: get_obj_to_scalar_method(param).unwrap(),
+                method: get_obj_to_scalar_method(param)?,
                 args: vec![reg_inf.array_val as u16],
             });
             insns.push(Instruction::MoveResultWide {
@@ -1472,10 +1479,10 @@ fn get_args_from_obj_arr(
         } else {
             insns.push(Instruction::CheckCast {
                 reg: reg_inf.array_val,
-                lit: get_obj_of_scalar(param).unwrap(),
+                lit: get_obj_of_scalar(param)?,
             });
             insns.push(Instruction::InvokeVirtual {
-                method: get_obj_to_scalar_method(param).unwrap(),
+                method: get_obj_to_scalar_method(param)?,
                 args: vec![reg_inf.array_val as u16],
             });
             insns.push(Instruction::MoveResult {
@@ -1489,7 +1496,7 @@ fn get_args_from_obj_arr(
         }
     }
     insns.append(&mut restore_array);
-    insns
+    Ok(insns)
 }
 
 pub(crate) static ABORD_LABELS: std::sync::LazyLock<
@@ -1557,7 +1564,7 @@ fn get_cnstr_new_inst_block(
         arg_arr,
         reg_inf.first_arg + 1,
         reg_inf,
-    ));
+    )?);
     if reg_inf.first_arg < u8::MAX as u16 {
         insns.push(Instruction::NewInstance {
             reg: reg_inf.first_arg as u8,