1/*-
2 * Copyright (c) 1998 Michael Smith
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/stand/libsa/sbrk.c 346476 2019-04-21 03:36:05Z kevans $");
29
30/*
31 * Minimal sbrk() emulation required for malloc support.
32 */
33
34#include <string.h>
35#include "stand.h"
36#include "zalloc_defs.h"
37
38static size_t	maxheap, heapsize = 0;
39static void	*heapbase;
40
41void
42setheap(void *base, void *top)
43{
44    /* Align start address for the malloc code.  Sigh. */
45    heapbase = (void *)(((uintptr_t)base + MALLOCALIGN_MASK) &
46        ~MALLOCALIGN_MASK);
47    maxheap = (char *)top - (char *)heapbase;
48}
49
50char *
51sbrk(int incr)
52{
53    char	*ret;
54
55    if (heapbase == 0)
56	    panic("No heap setup");
57
58    if ((heapsize + incr) <= maxheap) {
59	ret = (char *)heapbase + heapsize;
60	bzero(ret, incr);
61	heapsize += incr;
62	return(ret);
63    }
64    errno = ENOMEM;
65    return((char *)-1);
66}
67
68