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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak _sbrk = sbrk
#pragma weak _brk = brk
#include "lint.h"
#include <synch.h>
#include <errno.h>
#include <sys/isa_defs.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <inttypes.h>
#include <unistd.h>
#include "mtlib.h"
#include "libc.h"
void *_nd = NULL;
mutex_t __sbrk_lock = DEFAULTMUTEX;
extern intptr_t _brk_unlocked(void *);
void *_sbrk_unlocked(intptr_t);
/*
* The break must always be at least 8-byte aligned
*/
#if (_MAX_ALIGNMENT < 8)
#define ALIGNSZ 8
#else
#define ALIGNSZ _MAX_ALIGNMENT
#endif
#define BRKALIGN(x) (caddr_t)P2ROUNDUP((uintptr_t)(x), ALIGNSZ)
void *
sbrk(intptr_t addend)
{
void *result;
if (!primary_link_map) {
errno = ENOTSUP;
return ((void *)-1);
}
lmutex_lock(&__sbrk_lock);
result = _sbrk_unlocked(addend);
lmutex_unlock(&__sbrk_lock);
return (result);
}
/*
* _sbrk_unlocked() aligns the old break, adds the addend, aligns
* the new break, and calls _brk_unlocked() to set the new break.
* We must align the old break because _nd may begin life misaligned.
* The addend can be either positive or negative, so there are two
* overflow/underflow edge conditions to reject:
*
* - the addend is negative and brk + addend < 0.
* - the addend is positive and brk + addend > ULONG_MAX
*/
void *
_sbrk_unlocked(intptr_t addend)
{
char *old_brk;
char *new_brk;
if (_nd == NULL) {
_nd = (void *)_brk_unlocked(0);
}
old_brk = BRKALIGN(_nd);
new_brk = BRKALIGN(old_brk + addend);
if ((addend > 0 && new_brk < old_brk) ||
(addend < 0 && new_brk > old_brk)) {
errno = ENOMEM;
return ((void *)-1);
}
if (_brk_unlocked(new_brk) != 0)
return ((void *)-1);
_nd = new_brk;
return (old_brk);
}
/*
* _sbrk_grow_aligned() aligns the old break to a low_align boundry,
* adds min_size, aligns to a high_align boundry, and calls _brk_unlocked()
* to set the new break. The low_aligned-aligned value is returned, and
* the actual space allocated is returned through actual_size.
*
* Unlike sbrk(2), _sbrk_grow_aligned takes an unsigned size, and does
* not allow shrinking the heap.
*/
void *
_sbrk_grow_aligned(size_t min_size, size_t low_align, size_t high_align,
size_t *actual_size)
{
uintptr_t old_brk;
uintptr_t ret_brk;
uintptr_t high_brk;
uintptr_t new_brk;
intptr_t brk_result;
if (!primary_link_map) {
errno = ENOTSUP;
return ((void *)-1);
}
if ((low_align & (low_align - 1)) != 0 ||
(high_align & (high_align - 1)) != 0) {
errno = EINVAL;
return ((void *)-1);
}
low_align = MAX(low_align, ALIGNSZ);
high_align = MAX(high_align, ALIGNSZ);
lmutex_lock(&__sbrk_lock);
if (_nd == NULL)
_nd = (void *)_brk_unlocked(0);
old_brk = (uintptr_t)BRKALIGN(_nd);
ret_brk = P2ROUNDUP(old_brk, low_align);
high_brk = ret_brk + min_size;
new_brk = P2ROUNDUP(high_brk, high_align);
/*
* Check for overflow
*/
if (ret_brk < old_brk || high_brk < ret_brk || new_brk < high_brk) {
lmutex_unlock(&__sbrk_lock);
errno = ENOMEM;
return ((void *)-1);
}
if ((brk_result = _brk_unlocked((void *)new_brk)) == 0)
_nd = (void *)new_brk;
lmutex_unlock(&__sbrk_lock);
if (brk_result != 0)
return ((void *)-1);
if (actual_size != NULL)
*actual_size = (new_brk - ret_brk);
return ((void *)ret_brk);
}
int
brk(void *new_brk)
{
intptr_t result;
/*
* brk(2) will return the current brk if given an argument of 0, so we
* need to fail it here
*/
if (new_brk == 0) {
errno = ENOMEM;
return (-1);
}
if (!primary_link_map) {
errno = ENOTSUP;
return (-1);
}
/*
* Need to align this here; _brk_unlocked won't do it for us.
*/
new_brk = BRKALIGN(new_brk);
lmutex_lock(&__sbrk_lock);
if ((result = _brk_unlocked(new_brk)) == 0)
_nd = new_brk;
lmutex_unlock(&__sbrk_lock);
return (result);
}
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