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