Push demo

src/swizzle.m

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+/*****************************************************************************
+ * swizzle.m
+ * Build: gcc -dynamiclib -framework Foundation -o libswizzle.dylib swizzle.m -arch arm64
+ *****************************************************************************/
+
+#import <objc/runtime.h>
+#import <Foundation/Foundation.h>
+#include "include/VirtualizerSDK.h"
+#include "include/StealthCodeArea.h"
+
+int SwizzleStealthVar = 0;
+STEALTH_AUX_FUNCTION
+
+void SwizzleStealthCodeArea(void) {
+    STEALTH_AREA_START
+    STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK
+    STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK STEALTH_AREA_CHUNK
+    STEALTH_AREA_END
+}
+
+__attribute__((used))
+void ensure_stealth_area_compiled(void) {
+    if (SwizzleStealthVar == 0x11223344) SwizzleStealthCodeArea();
+}
+
+static inline void *swizzle_instance_method(const char *cls, const char *sel, void *imp) {
+    Method m = class_getInstanceMethod(objc_getClass(cls), sel_registerName(sel));
+    return method_setImplementation(m, imp);
+}
+
+static IMP original_description = NULL;
+
+id my_description(id self, SEL _cmd) {
+    VIRTUALIZER_START
+    
+    VIRTUALIZER_STR_ENCRYPT_START
+    const char *msg = "Swizzled :)";
+    VIRTUALIZER_STR_ENCRYPT_END
+    id result = [NSString stringWithUTF8String:msg];
+
+    VIRTUALIZER_END
+    return result;
+}
+
+id my_description_chained(id self, SEL _cmd) {
+    VIRTUALIZER_START
+
+    VIRTUALIZER_STR_ENCRYPT_START
+    const char *log_msg = "[Swizzle] Original: %@";
+    const char *msg = "Swizzled :)";
+    VIRTUALIZER_STR_ENCRYPT_END
+
+    if (original_description)
+        NSLog([NSString stringWithUTF8String:log_msg], ((id(*)(id,SEL))original_description)(self, _cmd));
+    id result = [NSString stringWithUTF8String:msg];
+
+    VIRTUALIZER_END
+    return result;
+}
+
+__attribute__((constructor))
+static void load(void) {
+    VIRTUALIZER_START
+
+    VIRTUALIZER_STR_ENCRYPT_START
+    const char *cls1 = "OriginalClass";
+    const char *sel1 = "original_selector";
+    const char *cls2 = "NSString";
+    const char *sel2 = "description";
+    VIRTUALIZER_STR_ENCRYPT_END
+
+    swizzle_instance_method(cls1, sel1, my_description);
+    original_description = swizzle_instance_method(cls2, sel2, my_description_chained);
+
+    VIRTUALIZER_END
+}