boost/interprocess/xsi_shared_memory.hpp

0001 //////////////////////////////////////////////////////////////////////////////
0002 //
0003 // (C) Copyright Ion Gaztanaga 2009-2012. Distributed under the Boost
0004 // Software License, Version 1.0. (See accompanying file
0005 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // See http://www.boost.org/libs/interprocess for documentation.
0008 //
0009 //////////////////////////////////////////////////////////////////////////////
0010
0011 #ifndef BOOST_INTERPROCESS_XSI_SHARED_MEMORY_HPP
0012 #define BOOST_INTERPROCESS_XSI_SHARED_MEMORY_HPP
0013
0014 #ifndef BOOST_CONFIG_HPP
0015 #  include <boost/config.hpp>
0016 #endif
0017 #
0018 #if defined(BOOST_HAS_PRAGMA_ONCE)
0019 #  pragma once
0020 #endif
0021
0022 #include <boost/interprocess/detail/config_begin.hpp>
0023 #include <boost/interprocess/detail/workaround.hpp>
0024
0025 #if !defined(BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS)
0026 #error "This header can't be used in operating systems without XSI (System V) shared memory support"
0027 #endif
0028
0029 #include <boost/interprocess/creation_tags.hpp>
0030 #include <boost/interprocess/exceptions.hpp>
0031 #include <boost/interprocess/detail/utilities.hpp>
0032
0033 #include <boost/interprocess/detail/os_file_functions.hpp>
0034 #include <boost/interprocess/interprocess_fwd.hpp>
0035 #include <boost/interprocess/exceptions.hpp>
0036 #include <boost/interprocess/xsi_key.hpp>
0037 #include <boost/interprocess/permissions.hpp>
0038 #include <boost/interprocess/detail/simple_swap.hpp>
0039 // move
0040 #include <boost/move/utility_core.hpp>
0041 // other boost
0042 #include <boost/cstdint.hpp>
0043 // std
0044 #include <cstddef>
0045 // OS
0046 #include <sys/shm.h>
0047
0048
0049 //!\file
0050 //!Describes a class representing a native xsi shared memory.
0051
0052 namespace boost {
0053 namespace interprocess {
0054
0055 //!A class that wraps XSI (System V) shared memory.
0056 //!Unlike shared_memory_object, xsi_shared_memory needs a valid
0057 //!xsi_key to identify a shared memory object.
0058 //!
0059 //!Warning: XSI shared memory and interprocess portable
0060 //!shared memory (boost::interprocess::shared_memory_object)
0061 //!can't communicate between them.
0062 class xsi_shared_memory
0063 {
0064    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
0065    //Non-copyable and non-assignable
0066    BOOST_MOVABLE_BUT_NOT_COPYABLE(xsi_shared_memory)
0067    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
0068
0069    public:
0070    //!Default constructor.
0071    //!Represents an empty xsi_shared_memory.
0072    xsi_shared_memory() BOOST_NOEXCEPT;
0073
0074    //!Initializes *this with a shmid previously obtained (possibly from another process)
0075    //!This lower-level initializer allows shared memory mapping without having a key.
0076    xsi_shared_memory(open_only_t, int shmid)
0077       : m_shmid (shmid)
0078    {}
0079
0080    //!Creates a new XSI shared memory from 'key', with size "size" and permissions "perm".
0081    //!If the shared memory previously exists, throws an error.
0082    xsi_shared_memory(create_only_t, const xsi_key &key, std::size_t size, const permissions& perm = permissions())
0083    {  this->priv_open_or_create(ipcdetail::DoCreate, key, perm, size);  }
0084
0085    //!Opens an existing shared memory with identifier 'key' or creates a new XSI shared memory from
0086    //!identifier 'key', with size "size" and permissions "perm".
0087    xsi_shared_memory(open_or_create_t, const xsi_key &key, std::size_t size, const permissions& perm = permissions())
0088    {  this->priv_open_or_create(ipcdetail::DoOpenOrCreate, key, perm, size);  }
0089
0090    //!Tries to open a XSI shared memory with identifier 'key'
0091    //!If the shared memory does not previously exist, it throws an error.
0092    xsi_shared_memory(open_only_t, const xsi_key &key)
0093    {  this->priv_open_or_create(ipcdetail::DoOpen, key, permissions(), 0);  }
0094
0095    //!Moves the ownership of "moved"'s shared memory object to *this.
0096    //!After the call, "moved" does not represent any shared memory object.
0097    //!Does not throw
0098    xsi_shared_memory(BOOST_RV_REF(xsi_shared_memory) moved) BOOST_NOEXCEPT
0099       : m_shmid(-1)
0100    {  this->swap(moved);   }
0101
0102    //!Moves the ownership of "moved"'s shared memory to *this.
0103    //!After the call, "moved" does not represent any shared memory.
0104    //!Does not throw
0105    xsi_shared_memory &operator=(BOOST_RV_REF(xsi_shared_memory) moved) BOOST_NOEXCEPT
0106    {
0107       xsi_shared_memory tmp(boost::move(moved));
0108       this->swap(tmp);
0109       return *this;
0110    }
0111
0112    //!Swaps two xsi_shared_memorys. Does not throw
0113    void swap(xsi_shared_memory &other) BOOST_NOEXCEPT;
0114
0115    //!Destroys *this. The shared memory won't be destroyed, just
0116    //!this connection to it. Use remove() to destroy the shared memory.
0117    ~xsi_shared_memory();
0118
0119    //!Returns the shared memory ID that
0120    //!identifies the shared memory
0121    int get_shmid() const BOOST_NOEXCEPT;
0122
0123    //!Returns the mapping handle.
0124    //!Never throws
0125    mapping_handle_t get_mapping_handle() const BOOST_NOEXCEPT;
0126
0127    //!Erases the XSI shared memory object identified by shmid
0128    //!from the system.
0129    //!Returns false on error. Never throws
0130    static bool remove(int shmid);
0131
0132    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
0133    private:
0134
0135    //!Closes a previously opened file mapping. Never throws.
0136    bool priv_open_or_create( ipcdetail::create_enum_t type
0137                            , const xsi_key &key
0138                            , const permissions& perm
0139                            , std::size_t size);
0140    int            m_shmid;
0141    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
0142 };
0143
0144 #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
0145
0146 inline xsi_shared_memory::xsi_shared_memory() BOOST_NOEXCEPT
0147    :  m_shmid(-1)
0148 {}
0149
0150 inline xsi_shared_memory::~xsi_shared_memory()
0151 {}
0152
0153 inline int xsi_shared_memory::get_shmid() const BOOST_NOEXCEPT
0154 {  return m_shmid; }
0155
0156 inline void xsi_shared_memory::swap(xsi_shared_memory &other) BOOST_NOEXCEPT
0157 {
0158    (simple_swap)(m_shmid, other.m_shmid);
0159 }
0160
0161 inline mapping_handle_t xsi_shared_memory::get_mapping_handle() const BOOST_NOEXCEPT
0162 {  mapping_handle_t mhnd = { m_shmid, true};   return mhnd;   }
0163
0164 inline bool xsi_shared_memory::priv_open_or_create
0165    (ipcdetail::create_enum_t type, const xsi_key &key, const permissions& permissions, std::size_t size)
0166 {
0167    int perm = (int)permissions.get_permissions();
0168    perm &= 0x01FF;
0169    int shmflg = perm;
0170
0171    switch(type){
0172       case ipcdetail::DoOpen:
0173          shmflg |= 0;
0174       break;
0175       case ipcdetail::DoCreate:
0176          shmflg |= IPC_CREAT | IPC_EXCL;
0177       break;
0178       case ipcdetail::DoOpenOrCreate:
0179          shmflg |= IPC_CREAT;
0180       break;
0181       default:
0182          {
0183             error_info err = other_error;
0184             throw interprocess_exception(err);
0185          }
0186    }
0187
0188    int ret = ::shmget(key.get_key(), size, shmflg);
0189    int shmid = ret;
0190    if((type == ipcdetail::DoOpen) && (-1 != ret)){
0191       //Now get the size
0192       ::shmid_ds xsi_ds;
0193       ret = ::shmctl(ret, IPC_STAT, &xsi_ds);
0194       size = xsi_ds.shm_segsz;
0195    }
0196    if(-1 == ret){
0197       error_info err = system_error_code();
0198       throw interprocess_exception(err);
0199    }
0200
0201    m_shmid = shmid;
0202    return true;
0203 }
0204
0205 inline bool xsi_shared_memory::remove(int shmid)
0206 {  return -1 != ::shmctl(shmid, IPC_RMID, 0); }
0207
0208 #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
0209
0210 }  //namespace interprocess {
0211 }  //namespace boost {
0212
0213 #include <boost/interprocess/detail/config_end.hpp>
0214
0215 #endif   //BOOST_INTERPROCESS_XSI_SHARED_MEMORY_HPP