From 90f330732f23835283ea533ceee5b3fd49132c02 Mon Sep 17 00:00:00 2001
From: p-x9 <50244599+p-x9@users.noreply.github.com>
Date: Fri, 16 Feb 2024 06:23:19 +0900
Subject: [PATCH 1/3] fix to avoid `EXC_BAD_ACCESS` when exchanging func
 implementation

---
 Sources/SwiftHook/SwiftHook+function.swift | 28 +++++++++++++---------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/Sources/SwiftHook/SwiftHook+function.swift b/Sources/SwiftHook/SwiftHook+function.swift
index 98ffe2e..d725f5d 100644
--- a/Sources/SwiftHook/SwiftHook+function.swift
+++ b/Sources/SwiftHook/SwiftHook+function.swift
@@ -41,7 +41,6 @@ extension SwiftHook {
         throw SwiftHookError.failedToExchangeFuncImplementation
     }
 
-
     public static func hookFunction(
         _ target: String,
         _ replacement: String,
@@ -130,6 +129,12 @@ extension SwiftHook {
         return (firstSymbol, secondSymbol)
     }
 
+}
+
+extension SwiftHook {
+    private static var replaced1: UnsafeMutableRawPointer?
+    private static var replaced2: UnsafeMutableRawPointer?
+
     @discardableResult
     private static func _exchangeFuncImplementation(
         _ first: String,
@@ -144,14 +149,16 @@ extension SwiftHook {
         print(firstSymbol, secondSymbol)
 #endif
 
-        var replaced1 = UnsafeMutableRawPointer(bitPattern: -1)
-        var replaced2 = UnsafeMutableRawPointer(bitPattern: -1)
-
+        // hook first function
+        replaced1 = nil
         let f2s: Bool = rebindSymbol(
             name: first,
             replacement: secondSymbol,
             replaced: &replaced1
         )
+
+        // hook second function
+        replaced2 = nil
         let s2f: Bool = rebindSymbol(
             name: second,
             replacement: firstSymbol,
@@ -162,19 +169,18 @@ extension SwiftHook {
             return false
         }
 
-        guard let replaced1,
-              Int(bitPattern: replaced1) != -1 else {
+        guard replaced1 != nil else {
             throw SwiftHookError.failedToHookFirstFunction
         }
-
-        guard let replaced2,
-              Int(bitPattern: replaced2) != -1 else {
+        guard replaced2 != nil else {
             throw SwiftHookError.failedToHookSecondFunction
         }
 
         return true
     }
+}
 
+extension SwiftHook {
     @discardableResult
     private static func _hookFuncImplementation(
         _ target: String,
@@ -193,7 +199,7 @@ extension SwiftHook {
         print(stdlib_demangleName(replacement))
 #endif
 
-        var replaced = UnsafeMutableRawPointer(bitPattern: -1)
+        var replaced: UnsafeMutableRawPointer?
 
         let result: Bool = rebindSymbol(
             name: target,
@@ -209,7 +215,7 @@ extension SwiftHook {
         }
 
         if let original {
-            var originalReplaced = UnsafeMutableRawPointer(bitPattern: -1)
+            var originalReplaced: UnsafeMutableRawPointer?
             let result: Bool = rebindSymbol(
                 name: original,
                 replacement: replaced,

From aa1c7a235e0899578da4bdcc8c817fa4886a07a7 Mon Sep 17 00:00:00 2001
From: p-x9 <50244599+p-x9@users.noreply.github.com>
Date: Fri, 16 Feb 2024 06:38:31 +0900
Subject: [PATCH 2/3] fix to avoid EXC_BAD_ACCESS when hooking functions

---
 Sources/SwiftHook/SwiftHook+function.swift | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Sources/SwiftHook/SwiftHook+function.swift b/Sources/SwiftHook/SwiftHook+function.swift
index d725f5d..5eb4142 100644
--- a/Sources/SwiftHook/SwiftHook+function.swift
+++ b/Sources/SwiftHook/SwiftHook+function.swift
@@ -199,18 +199,17 @@ extension SwiftHook {
         print(stdlib_demangleName(replacement))
 #endif
 
-        var replaced: UnsafeMutableRawPointer?
 
+        Self.replaced1 = nil
         let result: Bool = rebindSymbol(
             name: target,
             replacement: replacementSymbol,
-            replaced: &replaced
+            replaced: &Self.replaced1
         )
 
         guard result else { return false }
 
-        guard let replaced,
-              Int(bitPattern: replaced) != -1 else {
+        guard let replaced = Self.replaced1 else {
             return false
         }
 

From 6eaa38390471e49597cb361680262976dbeaa3e9 Mon Sep 17 00:00:00 2001
From: p-x9 <50244599+p-x9@users.noreply.github.com>
Date: Fri, 16 Feb 2024 06:39:16 +0900
Subject: [PATCH 3/3] refactor

---
 Sources/SwiftHook/SwiftHook+function.swift | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Sources/SwiftHook/SwiftHook+function.swift b/Sources/SwiftHook/SwiftHook+function.swift
index 5eb4142..41ddeb4 100644
--- a/Sources/SwiftHook/SwiftHook+function.swift
+++ b/Sources/SwiftHook/SwiftHook+function.swift
@@ -150,29 +150,29 @@ extension SwiftHook {
 #endif
 
         // hook first function
-        replaced1 = nil
+        Self.replaced1 = nil
         let f2s: Bool = rebindSymbol(
             name: first,
             replacement: secondSymbol,
-            replaced: &replaced1
+            replaced: &Self.replaced1
         )
 
         // hook second function
-        replaced2 = nil
+        Self.replaced2 = nil
         let s2f: Bool = rebindSymbol(
             name: second,
             replacement: firstSymbol,
-            replaced: &replaced2
+            replaced: &Self.replaced2
         )
 
         guard f2s && s2f else {
             return false
         }
 
-        guard replaced1 != nil else {
+        guard Self.replaced1 != nil else {
             throw SwiftHookError.failedToHookFirstFunction
         }
-        guard replaced2 != nil else {
+        guard Self.replaced2 != nil else {
             throw SwiftHookError.failedToHookSecondFunction
         }