trick

A library to hook functions and symbols

Tested on macOS in 32/64 bit environment

Tested on iOS in 64 bit environment

Installation

$ sudo make install

Usage

#import <iostream>
#import <string>
#import "trick.hpp"

using namespace std;
using namespace trick;

#pragma mark Hook function

__attribute__((visibility("hidden")))
void cpp_func(std::string via) {
	printf("cpp_func called %s\n", via.c_str());
}

static void (*orig_func)(std::string via);
void my_func(std::string via) {
	orig_func(via);
}

#pragma mark Hook global ariables

class foo {
public:
	int data;
};

static foo glob_foo;
static std::string glob_var;

int main(int argc, const char * argv[]) {
	glob_foo.data = 233;
	glob_var = "Hello";
	
	// Please note that the symbol name possibly *VARIES* when use different compilers and settings
	// In this example,
	/*
	 
	 Apple LLVM version 8.0.0 (clang-800.0.42.1)
	 Target: x86_64-apple-darwin16.1.0
	 Thread model: posix
	 Xcode version: Version 8.1 (8B62)
	 
	 */
	
#pragma mark symbol
	
	mach_vm_address_t addr = trick::get_symbol_address("_ZL8glob_var");
	printf("_ZL8glob_var: %p\n", (void *)addr);
	
	trick::get_symbol<std::string>("_ZL8glob_var") += " World!";
	printf("glob_var: %s\n", glob_var.c_str());
	
	addr = trick::get_symbol_address("_ZL8glob_foo");
	printf("_ZL8glob_foo: %p\n", (void *)addr);
	
	trick::get_symbol<class foo>("_ZL8glob_foo").data = 2333;
	printf("glob_foo.data: %d\n", glob_foo.data);
	
#pragma mark function
	
	cpp_func("directly");
	
	addr = trick::get_symbol_address("_Z8cpp_funcNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEE");
	printf("void cpp_func(std::string): %p\n", (void *)addr);
	
	trick::get_function<void(*)(std::string)>("_Z8cpp_funcNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEE")("via trick::get_function");
	return 0;
}

Screenshots

『桜Trick』