diff options
Diffstat (limited to 'lib/libstand/sbrk.c')
-rw-r--r-- | lib/libstand/sbrk.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/lib/libstand/sbrk.c b/lib/libstand/sbrk.c new file mode 100644 index 0000000..93d94e4 --- /dev/null +++ b/lib/libstand/sbrk.c @@ -0,0 +1,62 @@ +/*- + * Copyright (c) 1998 Michael Smith + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * Minimal sbrk() emulation required for malloc support. + */ + +#include <string.h> +#include "stand.h" + +static size_t maxheap, heapsize = 0; +static void *heapbase; + +void +setheap(void *base, void *top) +{ + /* Align start address to 16 bytes for the malloc code. Sigh. */ + heapbase = (void *)(((uintptr_t)base + 15) & ~15); + maxheap = (char *)top - (char *)heapbase; +} + +char * +sbrk(int incr) +{ + char *ret; + + if ((heapsize + incr) <= maxheap) { + ret = (char *)heapbase + heapsize; + bzero(ret, incr); + heapsize += incr; + return(ret); + } + errno = ENOMEM; + return((char *)-1); +} + |