1  /* Some auxiliary stuff for using mmap & friends.
       2     Copyright (C) 2002-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation; either version 2 of the License, or
       7     (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Bruno Haible.  */
      18  
      19  #if defined _WIN32 && !defined __CYGWIN__
      20  
      21  /* ------------------------ Windows ------------------------ */
      22  
      23  # define WIN32_LEAN_AND_MEAN /* avoid including junk */
      24  # include <windows.h>
      25  # include <winerror.h>
      26  # define PROT_NONE PAGE_NOACCESS
      27  # define PROT_READ PAGE_READONLY
      28  # define PROT_READ_WRITE PAGE_READWRITE
      29  
      30  static void *
      31  mmap_zeromap (void *map_addr_hint, size_t map_len)
      32  {
      33    if (VirtualAlloc ((void *)((uintptr_t) map_addr_hint & -0x10000),
      34                      (((uintptr_t) map_addr_hint + map_len - 1) | 0xffff) + 1
      35                      - ((uintptr_t) map_addr_hint & -0x10000),
      36                      MEM_RESERVE, PAGE_NOACCESS)
      37        && VirtualAlloc (map_addr_hint, map_len, MEM_COMMIT, PAGE_READWRITE))
      38      return map_addr_hint;
      39    else
      40      return (void *)(-1);
      41  }
      42  
      43  int
      44  munmap (void *addr, size_t len)
      45  {
      46    if (VirtualFree (addr, len, MEM_DECOMMIT))
      47      return 0;
      48    else
      49      return -1;
      50  }
      51  
      52  int
      53  mprotect (void *addr, size_t len, int prot)
      54  {
      55    DWORD oldprot;
      56  
      57    if (VirtualProtect (addr, len, prot, &oldprot))
      58      return 0;
      59    else
      60      return -1;
      61  }
      62  
      63  #else
      64  
      65  /* ------------------------ Unix ------------------------ */
      66  
      67  # include <sys/types.h>
      68  # include <sys/mman.h>
      69  # include <fcntl.h>
      70  
      71  # ifndef PROT_NONE
      72  #  define PROT_NONE 0
      73  # endif
      74  # define PROT_READ_WRITE  (PROT_READ|PROT_WRITE)
      75  
      76  # if HAVE_MAP_ANONYMOUS
      77  #  define zero_fd -1
      78  #  define map_flags MAP_ANONYMOUS | MAP_PRIVATE
      79  # else
      80  #  ifndef MAP_FILE
      81  #   define MAP_FILE 0
      82  #  endif
      83  static int zero_fd;
      84  #  define map_flags MAP_FILE | MAP_PRIVATE
      85  # endif
      86  
      87  static void *
      88  mmap_zeromap (void *map_addr_hint, size_t map_len)
      89  {
      90  # ifdef __hpux
      91    /* HP-UX 10 mmap() often fails when given a hint.  So give the OS complete
      92       freedom about the address range.  */
      93    return (void *) mmap ((void *) 0,    map_len, PROT_READ_WRITE, map_flags, zero_fd, 0);
      94  # else
      95    return (void *) mmap (map_addr_hint, map_len, PROT_READ_WRITE, map_flags, zero_fd, 0);
      96  # endif
      97  }
      98  
      99  #endif