#include <stdio.h> 
#include <unistd.h> 
#include <fcntl.h>    

typedef struct interpose_s {     
	void *new_func;     
	void *orig_func; 
} interpose_t;    

int my_open(const char *, int, mode_t); 
int my_close(int);    

static const interpose_t interposers[] 
	__attribute__ ((section("__DATA, __interpose"))) = {         
		{ (void *)my_open,  (void *)open  },         
		{ (void *)my_close, (void *)close },     
	}; 

int my_open(const char *path, int flags, mode_t mode) {     
	int ret = open(path, flags, mode);     
	printf("--> %d = open(%s, %x, %x)\n", ret, path, flags, mode);     
	return ret; 
}    

int my_close(int d) {     
	int ret = close(d);     
	printf("--> %d = close(%d)\n", ret, d);     
	return ret; 
}