text: /* $Id: allocex-r3-posix.cpp 69111 2017-10-17 14:26:02Z vboxsync $ */
  /** @file
   * IPRT - Memory Allocation, Extended Alloc Workers, posix.
   */
  
  /*
   * Copyright (C) 2006-2017 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/err.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);
  }
  
  