Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_SHARED_MEMORY_OBJECT_HPP
Chris@16: #define BOOST_INTERPROCESS_SHARED_MEMORY_OBJECT_HPP
Chris@16: 
Chris@101: #ifndef BOOST_CONFIG_HPP
Chris@101: #  include <boost/config.hpp>
Chris@101: #endif
Chris@101: #
Chris@101: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@101: #  pragma once
Chris@101: #endif
Chris@101: 
Chris@16: #include <boost/interprocess/detail/config_begin.hpp>
Chris@16: #include <boost/interprocess/detail/workaround.hpp>
Chris@16: #include <boost/interprocess/creation_tags.hpp>
Chris@16: #include <boost/interprocess/exceptions.hpp>
Chris@101: #include <boost/move/utility_core.hpp>
Chris@16: #include <boost/interprocess/interprocess_fwd.hpp>
Chris@16: #include <boost/interprocess/exceptions.hpp>
Chris@16: #include <boost/interprocess/detail/os_file_functions.hpp>
Chris@101: #include <boost/interprocess/detail/shared_dir_helpers.hpp>
Chris@16: #include <boost/interprocess/permissions.hpp>
Chris@101: #include <boost/move/adl_move_swap.hpp>
Chris@16: #include <cstddef>
Chris@16: #include <string>
Chris@16: 
Chris@101: #if defined(BOOST_INTERPROCESS_POSIX_SHARED_MEMORY_OBJECTS)
Chris@16: #  include <fcntl.h>        //O_CREAT, O_*...
Chris@16: #  include <sys/mman.h>     //shm_xxx
Chris@16: #  include <unistd.h>       //ftruncate, close
Chris@16: #  include <sys/stat.h>     //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
Chris@16: #  if defined(BOOST_INTERPROCESS_RUNTIME_FILESYSTEM_BASED_POSIX_SHARED_MEMORY)
Chris@16: #     if defined(__FreeBSD__)
Chris@16: #        include <sys/sysctl.h>
Chris@16: #     endif
Chris@16: #  endif
Chris@16: #else
Chris@16: //
Chris@16: #endif
Chris@16: 
Chris@16: //!\file
Chris@16: //!Describes a shared memory object management class.
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: 
Chris@16: //!A class that wraps a shared memory mapping that can be used to
Chris@16: //!create mapped regions from the mapped files
Chris@16: class shared_memory_object
Chris@16: {
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    //Non-copyable and non-assignable
Chris@16:    BOOST_MOVABLE_BUT_NOT_COPYABLE(shared_memory_object)
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16:    public:
Chris@16:    //!Default constructor. Represents an empty shared_memory_object.
Chris@16:    shared_memory_object();
Chris@16: 
Chris@16:    //!Creates a shared memory object with name "name" and mode "mode", with the access mode "mode"
Chris@16:    //!If the file previously exists, throws an error.*/
Chris@16:    shared_memory_object(create_only_t, const char *name, mode_t mode, const permissions &perm = permissions())
Chris@16:    {  this->priv_open_or_create(ipcdetail::DoCreate, name, mode, perm);  }
Chris@16: 
Chris@16:    //!Tries to create a shared memory object with name "name" and mode "mode", with the
Chris@16:    //!access mode "mode". If the file previously exists, it tries to open it with mode "mode".
Chris@16:    //!Otherwise throws an error.
Chris@16:    shared_memory_object(open_or_create_t, const char *name, mode_t mode, const permissions &perm = permissions())
Chris@16:    {  this->priv_open_or_create(ipcdetail::DoOpenOrCreate, name, mode, perm);  }
Chris@16: 
Chris@16:    //!Tries to open a shared memory object with name "name", with the access mode "mode".
Chris@16:    //!If the file does not previously exist, it throws an error.
Chris@16:    shared_memory_object(open_only_t, const char *name, mode_t mode)
Chris@16:    {  this->priv_open_or_create(ipcdetail::DoOpen, name, mode, permissions());  }
Chris@16: 
Chris@16:    //!Moves the ownership of "moved"'s shared memory object to *this.
Chris@16:    //!After the call, "moved" does not represent any shared memory object.
Chris@16:    //!Does not throw
Chris@16:    shared_memory_object(BOOST_RV_REF(shared_memory_object) moved)
Chris@16:       :  m_handle(file_handle_t(ipcdetail::invalid_file()))
Chris@16:       ,  m_mode(read_only)
Chris@16:    {  this->swap(moved);   }
Chris@16: 
Chris@16:    //!Moves the ownership of "moved"'s shared memory to *this.
Chris@16:    //!After the call, "moved" does not represent any shared memory.
Chris@16:    //!Does not throw
Chris@16:    shared_memory_object &operator=(BOOST_RV_REF(shared_memory_object) moved)
Chris@16:    {
Chris@16:       shared_memory_object tmp(boost::move(moved));
Chris@16:       this->swap(tmp);
Chris@16:       return *this;
Chris@16:    }
Chris@16: 
Chris@16:    //!Swaps the shared_memory_objects. Does not throw
Chris@16:    void swap(shared_memory_object &moved);
Chris@16: 
Chris@16:    //!Erases a shared memory object from the system.
Chris@16:    //!Returns false on error. Never throws
Chris@16:    static bool remove(const char *name);
Chris@16: 
Chris@16:    //!Sets the size of the shared memory mapping
Chris@16:    void truncate(offset_t length);
Chris@16: 
Chris@16:    //!Destroys *this and indicates that the calling process is finished using
Chris@16:    //!the resource. All mapped regions are still
Chris@16:    //!valid after destruction. The destructor function will deallocate
Chris@16:    //!any system resources allocated by the system for use by this process for
Chris@16:    //!this resource. The resource can still be opened again calling
Chris@16:    //!the open constructor overload. To erase the resource from the system
Chris@16:    //!use remove().
Chris@16:    ~shared_memory_object();
Chris@16: 
Chris@16:    //!Returns the name of the shared memory object.
Chris@16:    const char *get_name() const;
Chris@16: 
Chris@16:    //!Returns true if the size of the shared memory object
Chris@16:    //!can be obtained and writes the size in the passed reference
Chris@16:    bool get_size(offset_t &size) const;
Chris@16: 
Chris@16:    //!Returns access mode
Chris@16:    mode_t get_mode() const;
Chris@16: 
Chris@16:    //!Returns mapping handle. Never throws.
Chris@16:    mapping_handle_t get_mapping_handle() const;
Chris@16: 
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    private:
Chris@16: 
Chris@16:    //!Closes a previously opened file mapping. Never throws.
Chris@16:    void priv_close();
Chris@16: 
Chris@101:    //!Opens or creates a shared memory object.
Chris@16:    bool priv_open_or_create(ipcdetail::create_enum_t type, const char *filename, mode_t mode, const permissions &perm);
Chris@16: 
Chris@16:    file_handle_t  m_handle;
Chris@16:    mode_t         m_mode;
Chris@16:    std::string    m_filename;
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: };
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16: 
Chris@16: inline shared_memory_object::shared_memory_object()
Chris@16:    :  m_handle(file_handle_t(ipcdetail::invalid_file()))
Chris@16:    ,  m_mode(read_only)
Chris@16: {}
Chris@16: 
Chris@16: inline shared_memory_object::~shared_memory_object()
Chris@16: {  this->priv_close(); }
Chris@16: 
Chris@16: 
Chris@16: inline const char *shared_memory_object::get_name() const
Chris@16: {  return m_filename.c_str(); }
Chris@16: 
Chris@16: inline bool shared_memory_object::get_size(offset_t &size) const
Chris@16: {  return ipcdetail::get_file_size((file_handle_t)m_handle, size);  }
Chris@16: 
Chris@16: inline void shared_memory_object::swap(shared_memory_object &other)
Chris@16: {
Chris@101:    boost::adl_move_swap(m_handle, other.m_handle);
Chris@101:    boost::adl_move_swap(m_mode,   other.m_mode);
Chris@16:    m_filename.swap(other.m_filename);
Chris@16: }
Chris@16: 
Chris@16: inline mapping_handle_t shared_memory_object::get_mapping_handle() const
Chris@16: {
Chris@16:    return ipcdetail::mapping_handle_from_file_handle(m_handle);
Chris@16: }
Chris@16: 
Chris@16: inline mode_t shared_memory_object::get_mode() const
Chris@16: {  return m_mode; }
Chris@16: 
Chris@16: #if !defined(BOOST_INTERPROCESS_POSIX_SHARED_MEMORY_OBJECTS)
Chris@16: 
Chris@16: inline bool shared_memory_object::priv_open_or_create
Chris@16:    (ipcdetail::create_enum_t type, const char *filename, mode_t mode, const permissions &perm)
Chris@16: {
Chris@16:    m_filename = filename;
Chris@16:    std::string shmfile;
Chris@101:    ipcdetail::create_shared_dir_cleaning_old_and_get_filepath(filename, shmfile);
Chris@16: 
Chris@16:    //Set accesses
Chris@16:    if (mode != read_write && mode != read_only){
Chris@16:       error_info err = other_error;
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: 
Chris@16:    switch(type){
Chris@16:       case ipcdetail::DoOpen:
Chris@16:          m_handle = ipcdetail::open_existing_file(shmfile.c_str(), mode, true);
Chris@16:       break;
Chris@16:       case ipcdetail::DoCreate:
Chris@16:          m_handle = ipcdetail::create_new_file(shmfile.c_str(), mode, perm, true);
Chris@16:       break;
Chris@16:       case ipcdetail::DoOpenOrCreate:
Chris@16:          m_handle = ipcdetail::create_or_open_file(shmfile.c_str(), mode, perm, true);
Chris@16:       break;
Chris@16:       default:
Chris@16:          {
Chris@16:             error_info err = other_error;
Chris@16:             throw interprocess_exception(err);
Chris@16:          }
Chris@16:    }
Chris@16: 
Chris@16:    //Check for error
Chris@16:    if(m_handle == ipcdetail::invalid_file()){
Chris@16:       error_info err = system_error_code();
Chris@16:       this->priv_close();
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: 
Chris@16:    m_mode = mode;
Chris@16:    return true;
Chris@16: }
Chris@16: 
Chris@16: inline bool shared_memory_object::remove(const char *filename)
Chris@16: {
Chris@16:    try{
Chris@16:       //Make sure a temporary path is created for shared memory
Chris@16:       std::string shmfile;
Chris@101:       ipcdetail::shared_filepath(filename, shmfile);
Chris@16:       return ipcdetail::delete_file(shmfile.c_str());
Chris@16:    }
Chris@16:    catch(...){
Chris@16:       return false;
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void shared_memory_object::truncate(offset_t length)
Chris@16: {
Chris@16:    if(!ipcdetail::truncate_file(m_handle, length)){
Chris@16:       error_info err = system_error_code();
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void shared_memory_object::priv_close()
Chris@16: {
Chris@16:    if(m_handle != ipcdetail::invalid_file()){
Chris@16:       ipcdetail::close_file(m_handle);
Chris@16:       m_handle = ipcdetail::invalid_file();
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: #else //!defined(BOOST_INTERPROCESS_POSIX_SHARED_MEMORY_OBJECTS)
Chris@16: 
Chris@16: namespace shared_memory_object_detail {
Chris@16: 
Chris@16: #ifdef BOOST_INTERPROCESS_RUNTIME_FILESYSTEM_BASED_POSIX_SHARED_MEMORY
Chris@16: 
Chris@16: #if defined(__FreeBSD__)
Chris@16: 
Chris@16: inline bool use_filesystem_based_posix()
Chris@16: {
Chris@16:    int jailed = 0;
Chris@16:    std::size_t len = sizeof(jailed);
Chris@16:    ::sysctlbyname("security.jail.jailed", &jailed, &len, NULL, 0);
Chris@16:    return jailed != 0;
Chris@16: }
Chris@16: 
Chris@16: #else
Chris@16: #error "Not supported platform for BOOST_INTERPROCESS_RUNTIME_FILESYSTEM_BASED_POSIX_SHARED_MEMORY"
Chris@16: #endif
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: }  //shared_memory_object_detail
Chris@16: 
Chris@16: inline bool shared_memory_object::priv_open_or_create
Chris@16:    (ipcdetail::create_enum_t type,
Chris@16:     const char *filename,
Chris@16:     mode_t mode, const permissions &perm)
Chris@16: {
Chris@16:    #if defined(BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SHARED_MEMORY)
Chris@16:    const bool add_leading_slash = false;
Chris@16:    #elif defined(BOOST_INTERPROCESS_RUNTIME_FILESYSTEM_BASED_POSIX_SHARED_MEMORY)
Chris@16:    const bool add_leading_slash = !shared_memory_object_detail::use_filesystem_based_posix();
Chris@16:    #else
Chris@16:    const bool add_leading_slash = true;
Chris@16:    #endif
Chris@16:    if(add_leading_slash){
Chris@16:       ipcdetail::add_leading_slash(filename, m_filename);
Chris@16:    }
Chris@16:    else{
Chris@101:       ipcdetail::create_shared_dir_cleaning_old_and_get_filepath(filename, m_filename);
Chris@16:    }
Chris@16: 
Chris@16:    //Create new mapping
Chris@16:    int oflag = 0;
Chris@16:    if(mode == read_only){
Chris@16:       oflag |= O_RDONLY;
Chris@16:    }
Chris@16:    else if(mode == read_write){
Chris@16:       oflag |= O_RDWR;
Chris@16:    }
Chris@16:    else{
Chris@16:       error_info err(mode_error);
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16:    int unix_perm = perm.get_permissions();
Chris@16: 
Chris@16:    switch(type){
Chris@16:       case ipcdetail::DoOpen:
Chris@16:       {
Chris@16:          //No oflag addition
Chris@16:          m_handle = shm_open(m_filename.c_str(), oflag, unix_perm);
Chris@16:       }
Chris@16:       break;
Chris@16:       case ipcdetail::DoCreate:
Chris@16:       {
Chris@16:          oflag |= (O_CREAT | O_EXCL);
Chris@16:          m_handle = shm_open(m_filename.c_str(), oflag, unix_perm);
Chris@16:          if(m_handle >= 0){
Chris@16:             ::fchmod(m_handle, unix_perm);
Chris@16:          }
Chris@16:       }
Chris@16:       break;
Chris@16:       case ipcdetail::DoOpenOrCreate:
Chris@16:       {
Chris@16:          //We need a create/open loop to change permissions correctly using fchmod, since
Chris@16:          //with "O_CREAT" only we don't know if we've created or opened the shm.
Chris@16:          while(1){
Chris@16:             //Try to create shared memory
Chris@16:             m_handle = shm_open(m_filename.c_str(), oflag | (O_CREAT | O_EXCL), unix_perm);
Chris@16:             //If successful change real permissions
Chris@16:             if(m_handle >= 0){
Chris@16:                ::fchmod(m_handle, unix_perm);
Chris@16:             }
Chris@16:             //If already exists, try to open
Chris@16:             else if(errno == EEXIST){
Chris@16:                m_handle = shm_open(m_filename.c_str(), oflag, unix_perm);
Chris@16:                //If open fails and errno tells the file does not exist
Chris@16:                //(shm was removed between creation and opening tries), just retry
Chris@16:                if(m_handle < 0 && errno == ENOENT){
Chris@16:                   continue;
Chris@16:                }
Chris@16:             }
Chris@16:             //Exit retries
Chris@16:             break;
Chris@16:          }
Chris@16:       }
Chris@16:       break;
Chris@16:       default:
Chris@16:       {
Chris@16:          error_info err = other_error;
Chris@16:          throw interprocess_exception(err);
Chris@16:       }
Chris@16:    }
Chris@16: 
Chris@16:    //Check for error
Chris@16:    if(m_handle < 0){
Chris@16:       error_info err = errno;
Chris@16:       this->priv_close();
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: 
Chris@16:    m_filename = filename;
Chris@16:    m_mode = mode;
Chris@16:    return true;
Chris@16: }
Chris@16: 
Chris@16: inline bool shared_memory_object::remove(const char *filename)
Chris@16: {
Chris@16:    try{
Chris@101:       std::string filepath;
Chris@16:       #if defined(BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SHARED_MEMORY)
Chris@16:       const bool add_leading_slash = false;
Chris@16:       #elif defined(BOOST_INTERPROCESS_RUNTIME_FILESYSTEM_BASED_POSIX_SHARED_MEMORY)
Chris@16:       const bool add_leading_slash = !shared_memory_object_detail::use_filesystem_based_posix();
Chris@16:       #else
Chris@16:       const bool add_leading_slash = true;
Chris@16:       #endif
Chris@16:       if(add_leading_slash){
Chris@101:          ipcdetail::add_leading_slash(filename, filepath);
Chris@16:       }
Chris@16:       else{
Chris@101:          ipcdetail::shared_filepath(filename, filepath);
Chris@16:       }
Chris@101:       return 0 == shm_unlink(filepath.c_str());
Chris@16:    }
Chris@16:    catch(...){
Chris@16:       return false;
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void shared_memory_object::truncate(offset_t length)
Chris@16: {
Chris@16:    if(0 != ftruncate(m_handle, length)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void shared_memory_object::priv_close()
Chris@16: {
Chris@16:    if(m_handle != -1){
Chris@16:       ::close(m_handle);
Chris@16:       m_handle = -1;
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: //!A class that stores the name of a shared memory
Chris@16: //!and calls shared_memory_object::remove(name) in its destructor
Chris@16: //!Useful to remove temporary shared memory objects in the presence
Chris@16: //!of exceptions
Chris@16: class remove_shared_memory_on_destroy
Chris@16: {
Chris@16:    const char * m_name;
Chris@16:    public:
Chris@16:    remove_shared_memory_on_destroy(const char *name)
Chris@16:       :  m_name(name)
Chris@16:    {}
Chris@16: 
Chris@16:    ~remove_shared_memory_on_destroy()
Chris@16:    {  shared_memory_object::remove(m_name);  }
Chris@16: };
Chris@16: 
Chris@101: #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@101: 
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_end.hpp>
Chris@16: 
Chris@16: #endif   //BOOST_INTERPROCESS_SHARED_MEMORY_OBJECT_HPP