/*      $OpenBSD: mmap_size.c,v 1.3 2015/02/06 23:21:58 millert Exp $   */

/*
 * Public domain. 2005, Otto Moerbeek <otto@drijf.net>
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <err.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

void
f(size_t sz)
{
        char *p;
        p = mmap(NULL, sz, PROT_READ|PROT_WRITE,
            MAP_ANON|MAP_PRIVATE, -1, (off_t)0);

        if (p == MAP_FAILED)
                return;

        if (sz > 0) {
                p[0] = 0;
                p[sz / 2] = 0;
                p[sz - 1] = 0;
        }
        munmap(p, sz);
}

int
main()
{
        size_t i;

        for (i = 0; i < 0x2000; i += 0x100) {
                f(i);
                f(-i);
                f(SIZE_MAX/2 - 0x1000);
        }
        return (0);
}