xref: /titanic_51/usr/src/boot/lib/libstand/sbrk.c (revision 4a5d661a82b942b6538acd26209d959ce98b593a)
1*4a5d661aSToomas Soome /*-
2*4a5d661aSToomas Soome  * Copyright (c) 1998 Michael Smith
3*4a5d661aSToomas Soome  * All rights reserved.
4*4a5d661aSToomas Soome  *
5*4a5d661aSToomas Soome  * Redistribution and use in source and binary forms, with or without
6*4a5d661aSToomas Soome  * modification, are permitted provided that the following conditions
7*4a5d661aSToomas Soome  * are met:
8*4a5d661aSToomas Soome  * 1. Redistributions of source code must retain the above copyright
9*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer.
10*4a5d661aSToomas Soome  * 2. Redistributions in binary form must reproduce the above copyright
11*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer in the
12*4a5d661aSToomas Soome  *    documentation and/or other materials provided with the distribution.
13*4a5d661aSToomas Soome  *
14*4a5d661aSToomas Soome  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*4a5d661aSToomas Soome  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*4a5d661aSToomas Soome  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*4a5d661aSToomas Soome  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*4a5d661aSToomas Soome  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*4a5d661aSToomas Soome  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*4a5d661aSToomas Soome  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*4a5d661aSToomas Soome  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*4a5d661aSToomas Soome  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*4a5d661aSToomas Soome  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*4a5d661aSToomas Soome  * SUCH DAMAGE.
25*4a5d661aSToomas Soome  */
26*4a5d661aSToomas Soome 
27*4a5d661aSToomas Soome #include <sys/cdefs.h>
28*4a5d661aSToomas Soome __FBSDID("$FreeBSD$");
29*4a5d661aSToomas Soome 
30*4a5d661aSToomas Soome /*
31*4a5d661aSToomas Soome  * Minimal sbrk() emulation required for malloc support.
32*4a5d661aSToomas Soome  */
33*4a5d661aSToomas Soome 
34*4a5d661aSToomas Soome #include <string.h>
35*4a5d661aSToomas Soome #include "stand.h"
36*4a5d661aSToomas Soome #include "zalloc_defs.h"
37*4a5d661aSToomas Soome 
38*4a5d661aSToomas Soome static size_t	maxheap, heapsize = 0;
39*4a5d661aSToomas Soome static void	*heapbase;
40*4a5d661aSToomas Soome 
41*4a5d661aSToomas Soome void
42*4a5d661aSToomas Soome setheap(void *base, void *top)
43*4a5d661aSToomas Soome {
44*4a5d661aSToomas Soome     /* Align start address for the malloc code.  Sigh. */
45*4a5d661aSToomas Soome     heapbase = (void *)(((uintptr_t)base + MALLOCALIGN_MASK) &
46*4a5d661aSToomas Soome         ~MALLOCALIGN_MASK);
47*4a5d661aSToomas Soome     maxheap = (char *)top - (char *)heapbase;
48*4a5d661aSToomas Soome }
49*4a5d661aSToomas Soome 
50*4a5d661aSToomas Soome char *
51*4a5d661aSToomas Soome sbrk(int incr)
52*4a5d661aSToomas Soome {
53*4a5d661aSToomas Soome     char	*ret;
54*4a5d661aSToomas Soome 
55*4a5d661aSToomas Soome     if ((heapsize + incr) <= maxheap) {
56*4a5d661aSToomas Soome 	ret = (char *)heapbase + heapsize;
57*4a5d661aSToomas Soome 	bzero(ret, incr);
58*4a5d661aSToomas Soome 	heapsize += incr;
59*4a5d661aSToomas Soome 	return(ret);
60*4a5d661aSToomas Soome     }
61*4a5d661aSToomas Soome     errno = ENOMEM;
62*4a5d661aSToomas Soome     return((char *)-1);
63*4a5d661aSToomas Soome }
64*4a5d661aSToomas Soome 
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