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
29 /*
30 * Minimal sbrk() emulation required for malloc support.
31 */
32
33 #include <string.h>
34 #include "stand.h"
35 #include "zalloc_defs.h"
36
37 static size_t maxheap, heapsize = 0;
38 static void *heapbase;
39
40 void
setheap(void * base,void * top)41 setheap(void *base, void *top)
42 {
43 /* Align start address for the malloc code. Sigh. */
44 heapbase = (void *)(((uintptr_t)base + MALLOCALIGN_MASK) &
45 ~MALLOCALIGN_MASK);
46 maxheap = (char *)top - (char *)heapbase;
47 }
48
49 char *
sbrk(int incr)50 sbrk(int incr)
51 {
52 char *ret;
53
54 if (heapbase == NULL)
55 panic("No heap setup");
56
57 if ((heapsize + incr) <= maxheap) {
58 ret = (char *)heapbase + heapsize;
59 bzero(ret, incr);
60 heapsize += incr;
61 return (ret);
62 }
63 errno = ENOMEM;
64 return ((char *)-1);
65 }
66