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/****************************************************************
* *
* Copyright 2014 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include <sys/mman.h>
#include "mdef.h"
#include "memprot.h"
OS_PAGE_SIZE_DECLARE
/*
* Ensure base address has at least <size> bytes of accessible space, followed by an inaccessible (PROT_NONE) page.
*/
void memprot(mstr *base, uint4 size)
{
int status;
if (base->len < size)
{
if (NULL != base->addr)
munmap(base->addr, base->len + OS_PAGE_SIZE); /* clear previous allocation */
base->len = (mstr_len_t)ROUND_UP(size, OS_PAGE_SIZE);
base->addr = (char *)mmap(NULL, base->len + OS_PAGE_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (MAP_FAILED == base->addr)
{
base->len = 0;
base->addr = NULL;
} else
{
status = mprotect(base->addr + base->len, OS_PAGE_SIZE, PROT_NONE);
if (-1 == status)
{
munmap(base->addr, base->len + OS_PAGE_SIZE);
base->len = 0;
base->addr = NULL;
}
}
}
return;
}
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