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 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 * 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