sbrk.c revision 136093
139665Smsmith/*- 239665Smsmith * Copyright (c) 1998 Michael Smith 339665Smsmith * All rights reserved. 439665Smsmith * 539665Smsmith * Redistribution and use in source and binary forms, with or without 639665Smsmith * modification, are permitted provided that the following conditions 739665Smsmith * are met: 839665Smsmith * 1. Redistributions of source code must retain the above copyright 939665Smsmith * notice, this list of conditions and the following disclaimer. 1039665Smsmith * 2. Redistributions in binary form must reproduce the above copyright 1139665Smsmith * notice, this list of conditions and the following disclaimer in the 1239665Smsmith * documentation and/or other materials provided with the distribution. 1339665Smsmith * 1439665Smsmith * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1539665Smsmith * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1639665Smsmith * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1739665Smsmith * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1839665Smsmith * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1939665Smsmith * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2039665Smsmith * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2139665Smsmith * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2239665Smsmith * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2339665Smsmith * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2439665Smsmith * SUCH DAMAGE. 2539665Smsmith */ 2639665Smsmith 2784221Sdillon#include <sys/cdefs.h> 2884221Sdillon__FBSDID("$FreeBSD: head/lib/libstand/sbrk.c 136093 2004-10-03 15:58:20Z stefanf $"); 2984221Sdillon 3039665Smsmith/* 3139665Smsmith * Minimal sbrk() emulation required for malloc support. 3239665Smsmith */ 3339665Smsmith 3439665Smsmith#include <string.h> 3539665Smsmith#include "stand.h" 3639665Smsmith 3739665Smsmithstatic size_t maxheap, heapsize = 0; 3839665Smsmithstatic void *heapbase; 3939665Smsmith 4039665Smsmithvoid 4139665Smsmithsetheap(void *base, void *top) 4239665Smsmith{ 4360481Speter /* Align start address to 16 bytes for the malloc code. Sigh. */ 4460481Speter heapbase = (void *)(((uintptr_t)base + 15) & ~15); 45136093Sstefanf maxheap = (char *)top - (char *)heapbase; 4639665Smsmith} 4739665Smsmith 4839665Smsmithchar * 4939665Smsmithsbrk(int incr) 5039665Smsmith{ 5139665Smsmith char *ret; 5239665Smsmith 5339665Smsmith if ((heapsize + incr) <= maxheap) { 54136093Sstefanf ret = (char *)heapbase + heapsize; 5539665Smsmith bzero(ret, incr); 5639665Smsmith heapsize += incr; 5739665Smsmith return(ret); 5839665Smsmith } 5939665Smsmith errno = ENOMEM; 6039665Smsmith return((char *)-1); 6139665Smsmith} 6239665Smsmith 63