/*	$OpenBSD: mmap_hint.c,v 1.2 2013/03/21 21:59:55 deraadt Exp $	*/
/*
 * Copyright (c) 2011 Ariane van der Steldt <ariane@stack.nl>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <machine/vmparam.h>
#include <err.h>
#include <sysexits.h>
#include <stdio.h>

#define MAX_HINT_DIST	(2UL * 1024 * 1024 * 1024)

int	errors = 0;

void *
mmap_hint(void *hint)
{
	void	*p;
	size_t	 pd;

	p = mmap(hint, 1, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
	if (p == MAP_FAILED) {
		warn("mmap(addr=%p, len=1) failed", hint);
		errors++;
		return MAP_FAILED;
	} else if (p == NULL) {
		warnx("mmap(addr=%p, len=1) mapped at address 0", hint);
		errors++;
		return MAP_FAILED;
	} else
		fprintf(stderr, "    -> %p\n", p);

	if (hint > p)
		pd = hint - p;
	else
		pd = p - hint;

	if (hint != NULL && pd > MAX_HINT_DIST) {
		warnx("hinted allocation more than 0x%lx "
		    "bytes away from hint: "
		    "hint %p, result %p", pd, hint, p);
		errors++;
		return MAP_FAILED;
	}
	return p;
}

int
main()
{
	void	*p, *p_prev;

	/* Check that unhinted allocation works properly. */
	fprintf(stderr, "1: Checking hint NULL mmap\n");
	p = mmap_hint(NULL);

	/* Check hinted allocation at top of map. */
	fprintf(stderr, "2: Checking hint VM_MAXUSER_ADDRESS 0x%lx mmap\n",
	    (unsigned long)VM_MAXUSER_ADDRESS);
	p = mmap_hint((void*)VM_MAXUSER_ADDRESS);

	/* Check hinted allocation at bottom of map. */
	fprintf(stderr, "3: Checking hint VM_MIN_ADDRESS 0x%lx mmap\n",
	    (unsigned long)VM_MIN_ADDRESS);
	p = mmap_hint((void*)VM_MIN_ADDRESS);

	/*
	 * Check that hinted allocation doesn't overwrite existing allocation.
	 */
	if (p == MAP_FAILED) {
		fprintf(stderr, "4: Skipping test: required previous test "
		    "to succeed");
		goto skip4;
	}
	p_prev = p;
	fprintf(stderr, "4: Checking hint 0x%lx mmap, which is in use\n",
	    p_prev);
	p = mmap_hint(p_prev);
	if (p == p_prev) {
		warnx("hinted allocation %p "
		    "overwrites previous allocation", p_prev);
		errors++;
	}
skip4:

	return errors;
}