fishhook: A library that enables dynamically rebinding symbols in Mach-O binaries running on iOS.

#import <dlfcn.h>
#import "fishhook.h"

static OSStatus (*origin_AudioSessionSetProperty)(unsigned long, unsigned long, const void*);

void save_original_symbols() {
    origin_AudioSessionSetProperty = dlsym(RTLD_DEFAULT, "AudioSessionSetProperty");
}

OSStatus my_AudioSessionSetProperty(unsigned long inID, unsigned long inDataSize, const void *inData){
    printf("Calling real AudioSessionSetProperty: inID %ld  \n", inID);

    return origin_AudioSessionSetProperty(inID, inDataSize, inData);
}

int main(int argc, char * argv[]) {
 @autoreleasepool {
       save_original_symbols();
       rebind_symbols((struct rebinding[])AudioSessionSetProperty, 1);

       return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
     }
}

Aspects

Aspects: Delightful, simple library for aspect oriented programming.

[[AVAudioSession sharedInstance] aspect_hookSelector:@selector(setCategory:withOptions:error:) withOptions:0 usingBlock:^(id<AspectInfo> info,NSString *category, AVAudioSessionCategoryOptions option, NSError ** error){
    NSLog(@"AVAudioSession set category with category : %@", category);
}error:nil];

需要注意的一点，参数block需要与hook的函数相符，如果不匹配，会有如下提示：

Aspects: Block signature <NSMethodSignature: 0x7f93b8c35c80> doesn't match <NSMethodSignature: 0x7f93b8c33c30>.

fishhook和Aspects使用简单示例

Aspects