enable_execute_stack_test.c   [plain text]

//===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//


#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/mman.h>



extern void __clear_cache(void* start, void* end);
extern void __enable_execute_stack(void* addr);

typedef int (*pfunc)(void);

int func1() 
{
    return 1;
}

int func2() 
{
    return 2;
}




int main()
{
    unsigned char execution_buffer[128];
    // mark stack page containing execution_buffer to be executable
    __enable_execute_stack(execution_buffer);
	
    // verify you can copy and execute a function
    memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128);
    __clear_cache(execution_buffer, &execution_buffer[128]);
    pfunc f1 = (pfunc)(uintptr_t)execution_buffer;
    if ( (*f1)() != 1 )
        return 1;

    // verify you can overwrite a function with another
    memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128);
    __clear_cache(execution_buffer, &execution_buffer[128]);
    pfunc f2 = (pfunc)(uintptr_t)execution_buffer;
    if ( (*f2)() != 2 )
        return 1;

    return 0;
}