ceph/src/boost/libs/interprocess/include/boost/interprocess/anonymous_shared_memory.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
  12 #define BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP
  13
  14 #ifndef BOOST_CONFIG_HPP
  15 #  include <boost/config.hpp>
  16 #endif
  17 #
  18 #if defined(BOOST_HAS_PRAGMA_ONCE)
  19 #  pragma once
  20 #endif
  21
  22 #include <boost/interprocess/detail/config_begin.hpp>
  23 #include <boost/interprocess/detail/workaround.hpp>
  24 #include <boost/interprocess/creation_tags.hpp>
  25 #include <boost/move/move.hpp>
  26 #include <boost/interprocess/interprocess_fwd.hpp>
  27 #include <boost/interprocess/mapped_region.hpp>
  28 #include <cstddef>
  29
  30 #if (!defined(BOOST_INTERPROCESS_WINDOWS))
  31 #  include <fcntl.h>        //open, O_CREAT, O_*...
  32 #  include <sys/mman.h>     //mmap
  33 #  include <sys/stat.h>     //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
  34 #else
  35 #include <boost/interprocess/windows_shared_memory.hpp>
  36 #endif
  37
  38
  39 //!\file
  40 //!Describes a function that creates anonymous shared memory that can be
  41 //!shared between forked processes
  42
  43 namespace boost {
  44 namespace interprocess {
  45
  46 #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  47
  48 namespace ipcdetail{
  49
  50    class raw_mapped_region_creator
  51    {
  52       public:
  53       static mapped_region
  54          create_posix_mapped_region(void *address, std::size_t size)
  55       {
  56          mapped_region region;
  57          region.m_base = address;
  58          region.m_size = size;
  59          return region;
  60       }
  61    };
  62 }
  63
  64 #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
  65
  66 //!A function that creates an anonymous shared memory segment of size "size".
  67 //!If "address" is passed the function will try to map the segment in that address.
  68 //!Otherwise the operating system will choose the mapping address.
  69 //!The function returns a mapped_region holding that segment or throws
  70 //!interprocess_exception if the function fails.
  71 //static mapped_region
  72 static mapped_region
  73 anonymous_shared_memory(std::size_t size, void *address = 0)
  74 #if (!defined(BOOST_INTERPROCESS_WINDOWS))
  75 {
  76    int flags;
  77    int fd = -1;
  78
  79    #if defined(MAP_ANONYMOUS) //Use MAP_ANONYMOUS
  80    flags = MAP_ANONYMOUS | MAP_SHARED;
  81    #elif !defined(MAP_ANONYMOUS) && defined(MAP_ANON) //use MAP_ANON
  82    flags = MAP_ANON | MAP_SHARED;
  83    #else // Use "/dev/zero"
  84    fd = open("/dev/zero", O_RDWR);
  85    flags = MAP_SHARED;
  86    if(fd == -1){
  87       error_info err = system_error_code();
  88       throw interprocess_exception(err);
  89    }
  90    #endif
  91
  92
  93    address = mmap( address
  94                   , size
  95                   , PROT_READ|PROT_WRITE
  96                   , flags
  97                   , fd
  98                   , 0);
  99
 100    if(address == MAP_FAILED){
 101       if(fd != -1)
 102          close(fd);
 103       error_info err = system_error_code();
 104       throw interprocess_exception(err);
 105    }
 106
 107    if(fd != -1)
 108       close(fd);
 109
 110    return ipcdetail::raw_mapped_region_creator::create_posix_mapped_region(address, size);
 111 }
 112 #else
 113 {
 114    windows_shared_memory anonymous_mapping(create_only, 0, read_write, size);
 115    return mapped_region(anonymous_mapping, read_write, 0, size, address);
 116 }
 117
 118 #endif
 119
 120 }  //namespace interprocess {
 121 }  //namespace boost {
 122
 123 #include <boost/interprocess/detail/config_end.hpp>
 124
 125 #endif   //BOOST_INTERPROCESS_ANONYMOUS_SHARED_MEMORY_HPP