From 86f466cdb02ea1a81c0d6bca96dcb1fc054e818d Mon Sep 17 00:00:00 2001
From: Erin <erin@erindesu.cz>
Date: Sun, 8 May 2022 13:32:19 +0200
Subject: [PATCH] Simplified signature checking in wasm jumploader

---
 ableos/src/wasm_jumploader/host_functions.rs | 118 +++----------------
 1 file changed, 17 insertions(+), 101 deletions(-)

diff --git a/ableos/src/wasm_jumploader/host_functions.rs b/ableos/src/wasm_jumploader/host_functions.rs
index 04c5055..a4f4d44 100644
--- a/ableos/src/wasm_jumploader/host_functions.rs
+++ b/ableos/src/wasm_jumploader/host_functions.rs
@@ -14,108 +14,24 @@ const SEND_SIGNAL_INDEX: usize = 1;
 pub struct HostExternals;
 impl HostExternals {
     fn check_signature(&self, index: usize, signature: &Signature) -> bool {
-        match index {
-            ADD_FUNC_INDEX => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) =
-                    (&[ValueType::I32, ValueType::I32], Some(ValueType::I32));
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
+        let (params, ret_ty): (&[_], _) = match index {
+            ADD_FUNC_INDEX => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
+            SEND_SIGNAL_INDEX => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
+            GET_TIME_INDEX => (&[], Some(ValueType::I32)),
+            GET_RANDOM_INDEX => (&[], Some(ValueType::I32)),
+            GET_INPUT_INDEX => (&[], Some(ValueType::I32)),
+            PRINT_CHAR => (&[ValueType::I32], None),
+            _ => return false,
+        };
 
-            SEND_SIGNAL_INDEX => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) =
-                    (&[ValueType::I32, ValueType::I32], Some(ValueType::I32));
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
-
-            GET_TIME_INDEX => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) =
-                    (&[], Some(ValueType::I32));
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
-
-            GET_RANDOM_INDEX => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) =
-                    (&[], Some(ValueType::I32));
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
-
-            GET_INPUT_INDEX => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) =
-                    (&[], Some(ValueType::I32));
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
-
-            PRINT_CHAR => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) = (&[ValueType::I32], None);
-                if params.len() != signature.params().len() {
-                    return false;
-                }
-                if ret_ty != signature.return_type() {
-                    return false;
-                }
-                for (ty, param) in params.iter().zip(signature.params()) {
-                    if *ty != *param {
-                        return false;
-                    }
-                }
-                true
-            }
-            _ => false,
+        if params.len() != signature.params().len() || ret_ty != signature.return_type() {
+            false
+        } else {
+            params
+                .iter()
+                .zip(signature.params())
+                .find(|(ty, param)| ty != param)
+                .is_none()
         }
     }
 }