/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2018 Mark Johnston <markj@FreeBSD.org>
*
* 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/types.h>
#include <sys/syscall.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
void *__sys_break(char *nsize);
static uintptr_t curbrk, minbrk;
static int curbrk_initted;
static int
initbrk(void)
{
void *newbrk;
if (!curbrk_initted) {
newbrk = __sys_break(NULL);
if (newbrk == (void *)-1)
return (-1);
curbrk = minbrk = (uintptr_t)newbrk;
curbrk_initted = 1;
}
return (0);
}
static void *
mvbrk(void *addr)
{
uintptr_t oldbrk;
if ((uintptr_t)addr < minbrk) {
/* Emulate legacy error handling in the syscall. */
errno = EINVAL;
return ((void *)-1);
}
if (__sys_break(addr) == (void *)-1)
return ((void *)-1);
oldbrk = curbrk;
curbrk = (uintptr_t)addr;
return ((void *)oldbrk);
}
int
brk(const void *addr)
{
if (initbrk() == -1)
return (-1);
if ((uintptr_t)addr < minbrk)
addr = (void *)minbrk;
return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0);
}
int
_brk(const void *addr)
{
if (initbrk() == -1)
return (-1);
return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0);
}
void *
sbrk(intptr_t incr)
{
if (initbrk() == -1)
return ((void *)-1);
if ((incr > 0 && curbrk + incr < curbrk) ||
(incr < 0 && curbrk + incr > curbrk)) {
/* Emulate legacy error handling in the syscall. */
errno = EINVAL;
return ((void *)-1);
}
return (mvbrk((void *)(curbrk + incr)));
}
