#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>

int main(void)
{
	void *addr;
	size_t size, page_size;

        page_size = getpagesize();
	printf("Page size : %i\n", (int)page_size);
        size = 6 * (int)page_size;

        addr = mmap((caddr_t)0,
	            size,
	            (PROT_READ | PROT_WRITE),
	            (MAP_PRIVATE | MAP_ANONYMOUS),
	            0,
	            0);
	if (addr == MAP_FAILED)
	{
		printf("mmap() failed !\n");
                return 1;
	}
	printf("Address   : %X\n", (int)addr);

	if (memset(addr, 0, size) != addr)
	{
		printf("memset() failed !\n");
                return 2;
	}

	if (mprotect((caddr_t)addr, size, (PROT_NONE)) != 0)
	{
		printf("mprotect() (1) failed : %s\n", strerror(errno));
                return 3;
	}

	if (mprotect((caddr_t)addr, size, (PROT_READ)) != 0)
	{
		printf("mprotect() (2) failed : %s\n", strerror(errno));
                return 3;
	}

	if (mprotect((caddr_t)addr, size, (PROT_READ | PROT_WRITE)) != 0)
	{
		printf("mprotect() (3) failed : %s\n", strerror(errno));
                return 3;
	}

	if (memset(addr, 1, size) != addr)
	{
		printf("memset() failed !\n");
                return 4;
	}

	return 0;
}