/* $Id: allocex-r3-posix.cpp $ */
/** @file
 * IPRT - Memory Allocation, Extended Alloc Workers, posix.
 */

/*
 * Copyright (C) 2006-2019 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define RTMEM_NO_WRAP_TO_EF_APIS
#include <iprt/mem.h>
#include "internal/iprt.h"

#include <iprt/assert.h>
#include <iprt/errcore.h>
#include <iprt/string.h>
#include "../allocex.h"

#include <sys/mman.h>


DECLHIDDEN(int) rtMemAllocEx16BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
{
    AssertReturn(cbAlloc < _64K, VERR_NO_MEMORY);

    /*
     * Try with every possible address hint since the possible range is very limited.
     */
    int       fProt     = PROT_READ | PROT_WRITE | (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PROT_EXEC : 0);
    uintptr_t uAddr     = 0x1000;
    uintptr_t uAddrLast = _64K - uAddr - cbAlloc;
    while (uAddr <= uAddrLast)
    {
        void *pv = mmap((void *)uAddr, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        if (pv && (uintptr_t)pv <= uAddrLast)
        {
            *ppv = pv;
            return VINF_SUCCESS;
        }

        if (pv)
        {
            munmap(pv, cbAlloc);
            pv = NULL;
        }
        uAddr += _4K;
    }

    return VERR_NO_MEMORY;
}


DECLHIDDEN(int) rtMemAllocEx32BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
{
    int     fProt = PROT_READ | PROT_WRITE | (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PROT_EXEC : 0);
#if ARCH_BITS == 32
    void   *pv = mmap(NULL, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    if (pv)
    {
        *ppv = pv;
        return VINF_SUCCESS;
    }
    return VERR_NO_MEMORY;

#elif defined(RT_OS_LINUX)
# ifdef MAP_32BIT
    void *pv = mmap(NULL, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
    if (pv)
    {
        *ppv = pv;
        return VINF_SUCCESS;
    }
# endif

    /** @todo On linux, we need an accurate hint. Since I don't need this branch of
     *        the code right now, I won't bother starting to parse
     *        /proc/curproc/mmap right now... */
#else
#endif
    return VERR_NOT_SUPPORTED;
}


DECLHIDDEN(void) rtMemFreeExYyBitReach(void *pv, size_t cb, uint32_t fFlags)
{
    RT_NOREF_PV(fFlags);
    munmap(pv, cb);
}