x86 Relative String Addressing Hack

x86_relative_shellcode_strings.c

#include <stdio.h>

#define DECLARE_STRING(var, str)  __attribute__((section(".text"))) char var[] = "\xe8\x00\x00\x00\x00\x58\x83\xc0\x05\xc3" str;
#define REF_STRING(var) ((char*(*)())var)()

DECLARE_STRING(data1, "Hello, World!\n");
DECLARE_STRING(data2, "Goodbye, World!\n");

int main(int , char** )
{
    printf("%s", REF_STRING(data1));
    printf("%s", REF_STRING(data2));
}