1/*
2 * Copyright (c) 1999-2010 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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23 * Please see the License for the specific language governing rights and
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27 */
28/*
29 *	File:	brk.c
30 *
31 *	Unix compatibility for sbrk system call.
32 *
33 * HISTORY
34 * 09-Mar-90  Gregg Kellogg (gk) at NeXT.
35 *	include <kern/mach_interface.h> instead of <kern/mach.h>
36 *
37 * 14-Feb-89  Avadis Tevanian (avie) at NeXT.
38 *	Total rewrite using a fixed area of VM from break region.
39 */
40
41#include <mach/mach.h>		/* for vm_allocate, vm_offset_t */
42#include <mach/vm_statistics.h>
43#include <errno.h>
44#include <unistd.h>
45
46static int sbrk_needs_init = TRUE;
47static vm_size_t sbrk_region_size = 4*1024*1024; /* Well, what should it be? */
48static vm_address_t sbrk_curbrk;
49
50void *sbrk(int size)
51{
52	kern_return_t	ret;
53
54	if (sbrk_needs_init) {
55		sbrk_needs_init = FALSE;
56		/*
57		 *	Allocate a big region to simulate break region.
58		 */
59		ret =  vm_allocate(mach_task_self(), &sbrk_curbrk, sbrk_region_size,
60				  VM_MAKE_TAG(VM_MEMORY_SBRK)|TRUE);
61		if (ret != KERN_SUCCESS) {
62			errno = ENOMEM;
63			return((void *)-1);
64		}
65	}
66
67	if (size <= 0)
68		return((void *)sbrk_curbrk);
69	else if (size > sbrk_region_size) {
70		errno = ENOMEM;
71		return((void *)-1);
72	}
73	sbrk_curbrk += size;
74	sbrk_region_size -= size;
75	return((void *)(sbrk_curbrk - size));
76}
77
78void *brk(const void *x)
79{
80	errno = ENOMEM;
81	return((void *)-1);
82}
83