boost/interprocess/detail/managed_open_or_create_impl.hpp
////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2006-2012. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // See http://www.boost.org/libs/interprocess for documentation. // ////////////////////////////////////////////////////////////////////////////// #ifndef BOOST_INTERPROCESS_MANAGED_OPEN_OR_CREATE_IMPL #define BOOST_INTERPROCESS_MANAGED_OPEN_OR_CREATE_IMPL #ifndef BOOST_CONFIG_HPP # include <boost/config.hpp> #endif # #if defined(BOOST_HAS_PRAGMA_ONCE) # pragma once #endif #include <boost/interprocess/detail/config_begin.hpp> #include <boost/interprocess/detail/os_thread_functions.hpp> #include <boost/interprocess/detail/os_file_functions.hpp> #include <boost/interprocess/creation_tags.hpp> #include <boost/interprocess/mapped_region.hpp> #include <boost/interprocess/detail/utilities.hpp> #include <boost/interprocess/detail/type_traits.hpp> #include <boost/interprocess/detail/atomic.hpp> #include <boost/interprocess/detail/interprocess_tester.hpp> #include <boost/interprocess/creation_tags.hpp> #include <boost/interprocess/detail/mpl.hpp> #include <boost/interprocess/permissions.hpp> #include <boost/container/detail/type_traits.hpp> //alignment_of, aligned_storage #include <boost/interprocess/sync/spin/wait.hpp> #include <boost/interprocess/timed_utils.hpp> #include <boost/move/move.hpp> #include <boost/cstdint.hpp> namespace boost { namespace interprocess { namespace ipcdetail { template <bool StoreDevice, class DeviceAbstraction> class managed_open_or_create_impl_device_holder { public: DeviceAbstraction &get_device() { static DeviceAbstraction dev; return dev; } const DeviceAbstraction &get_device() const { static DeviceAbstraction dev; return dev; } }; template <class DeviceAbstraction> class managed_open_or_create_impl_device_holder<true, DeviceAbstraction> { public: DeviceAbstraction &get_device() { return dev; } const DeviceAbstraction &get_device() const { return dev; } private: DeviceAbstraction dev; }; template<class DeviceAbstraction, std::size_t MemAlignment, bool FileBased, bool StoreDevice> class managed_open_or_create_impl : public managed_open_or_create_impl_device_holder<StoreDevice, DeviceAbstraction> { //Non-copyable BOOST_MOVABLE_BUT_NOT_COPYABLE(managed_open_or_create_impl) typedef bool_<FileBased> file_like_t; static const unsigned MaxCreateOrOpenTries = BOOST_INTERPROCESS_MANAGED_OPEN_OR_CREATE_INITIALIZE_MAX_TRIES; static const unsigned MaxInitializeTimeSec = BOOST_INTERPROCESS_MANAGED_OPEN_OR_CREATE_INITIALIZE_TIMEOUT_SEC; typedef managed_open_or_create_impl_device_holder<StoreDevice, DeviceAbstraction> DevHolder; enum { UninitializedSegment, InitializingSegment, InitializedSegment, CorruptedSegment }; static const std::size_t RequiredAlignment = MemAlignment ? MemAlignment : boost::container::dtl::alignment_of< boost::container::dtl::max_align_t >::value ; public: static const std::size_t ManagedOpenOrCreateUserOffset = ct_rounded_size<sizeof(boost::uint32_t), RequiredAlignment>::value; managed_open_or_create_impl() {} template <class DeviceId> managed_open_or_create_impl(create_only_t, const DeviceId & id, std::size_t size, mode_t mode, const void *addr, const permissions &perm) { priv_open_or_create ( DoCreate , id , size , mode , addr , perm , null_mapped_region_function()); } template <class DeviceId> managed_open_or_create_impl(open_only_t, const DeviceId & id, mode_t mode, const void *addr) { priv_open_or_create ( DoOpen , id , 0 , mode , addr , permissions() , null_mapped_region_function()); } template <class DeviceId> managed_open_or_create_impl(open_or_create_t, const DeviceId & id, std::size_t size, mode_t mode, const void *addr, const permissions &perm) { priv_open_or_create ( DoOpenOrCreate , id , size , mode , addr , perm , null_mapped_region_function()); } template <class DeviceId, class ConstructFunc> managed_open_or_create_impl(create_only_t, const DeviceId & id, std::size_t size, mode_t mode, const void *addr, const ConstructFunc &construct_func, const permissions &perm) { priv_open_or_create (DoCreate , id , size , mode , addr , perm , construct_func); } template <class DeviceId, class ConstructFunc> managed_open_or_create_impl(open_only_t, const DeviceId & id, mode_t mode, const void *addr, const ConstructFunc &construct_func) { priv_open_or_create ( DoOpen , id , 0 , mode , addr , permissions() , construct_func); } template <class DeviceId, class ConstructFunc> managed_open_or_create_impl(open_or_create_t, const DeviceId & id, std::size_t size, mode_t mode, const void *addr, const ConstructFunc &construct_func, const permissions &perm) { priv_open_or_create ( DoOpenOrCreate , id , size , mode , addr , perm , construct_func); } managed_open_or_create_impl(BOOST_RV_REF(managed_open_or_create_impl) moved) { this->swap(moved); } managed_open_or_create_impl &operator=(BOOST_RV_REF(managed_open_or_create_impl) moved) { managed_open_or_create_impl tmp(boost::move(moved)); this->swap(tmp); return *this; } ~managed_open_or_create_impl() {} std::size_t get_user_size() const { return m_mapped_region.get_size() - ManagedOpenOrCreateUserOffset; } void *get_user_address() const { return static_cast<char*>(m_mapped_region.get_address()) + ManagedOpenOrCreateUserOffset; } std::size_t get_real_size() const { return m_mapped_region.get_size(); } void *get_real_address() const { return m_mapped_region.get_address(); } void swap(managed_open_or_create_impl &other) { this->m_mapped_region.swap(other.m_mapped_region); } bool flush() { return m_mapped_region.flush(); } const mapped_region &get_mapped_region() const { return m_mapped_region; } DeviceAbstraction &get_device() { return this->DevHolder::get_device(); } const DeviceAbstraction &get_device() const { return this->DevHolder::get_device(); } private: //These are templatized to allow explicit instantiations template<bool dummy> static void truncate_device(DeviceAbstraction &, offset_t, false_) {} //Empty template<bool dummy> static void truncate_device(DeviceAbstraction &dev, offset_t size, true_) { dev.truncate(size); } template<bool dummy> static bool check_offset_t_size(std::size_t , false_) { return true; } //Empty template<bool dummy> static bool check_offset_t_size(std::size_t size, true_) { return size == std::size_t(offset_t(size)); } //These are templatized to allow explicit instantiations template<bool dummy, class DeviceId> static void create_device(DeviceAbstraction &dev, const DeviceId & id, std::size_t size, const permissions &perm, false_ /*file_like*/) { DeviceAbstraction tmp(create_only, id, read_write, size, perm); tmp.swap(dev); } template<bool dummy, class DeviceId> static void create_device(DeviceAbstraction &dev, const DeviceId & id, std::size_t, const permissions &perm, true_ /*file_like*/) { DeviceAbstraction tmp(create_only, id, read_write, perm); tmp.swap(dev); } template <class DeviceId> static bool do_create_else_open(DeviceAbstraction &dev, const DeviceId & id, std::size_t size, const permissions &perm) { //This loop is very ugly, but brute force is sometimes better //than diplomacy. In POSIX file-based resources we can' know if we //effectively created the file or not (there is no ERROR_ALREADY_EXISTS equivalent), //so we try to create exclusively and fallback to open if already exists, with //some retries if opening also fails because the file does not exist //(there is a race, the creator just removed the file after creating it). // //We'll put a maximum retry limit just to avoid possible deadlocks, we don't //want to support pathological use cases. spin_wait swait; unsigned tries = 0; while(1){ BOOST_TRY{ create_device<FileBased>(dev, id, size, perm, file_like_t()); return true; } BOOST_CATCH(interprocess_exception &ex){ #ifndef BOOST_NO_EXCEPTIONS if(ex.get_error_code() != already_exists_error){ BOOST_RETHROW } else if (++tries == MaxCreateOrOpenTries) { //File existing when trying to create, but non-existing when //trying to open, and tried MaxCreateOrOpenTries times. Something fishy //is happening here and we can't solve it throw interprocess_exception(error_info(corrupted_error)); } else{ BOOST_TRY{ DeviceAbstraction tmp(open_only, id, read_write); dev.swap(tmp); return false; } BOOST_CATCH(interprocess_exception &e){ if(e.get_error_code() != not_found_error){ BOOST_RETHROW } } BOOST_CATCH(...){ BOOST_RETHROW } BOOST_CATCH_END } #endif //#ifndef BOOST_NO_EXCEPTIONS } BOOST_CATCH(...){ BOOST_RETHROW } BOOST_CATCH_END swait.yield(); } return false; } template <class ConstructFunc> static void do_map_after_create (DeviceAbstraction &dev, mapped_region &final_region, std::size_t size, const void *addr, ConstructFunc construct_func) { BOOST_TRY{ //If this throws, we are lost truncate_device<FileBased>(dev, static_cast<offset_t>(size), file_like_t()); //If the following throws, we will truncate the file to 1 mapped_region region(dev, read_write, 0, 0, addr); boost::uint32_t *patomic_word = 0; //avoid gcc warning patomic_word = static_cast<boost::uint32_t*>(region.get_address()); boost::uint32_t previous = atomic_cas32(patomic_word, InitializingSegment, UninitializedSegment); if(previous == UninitializedSegment){ BOOST_TRY{ construct_func( static_cast<char*>(region.get_address()) + ManagedOpenOrCreateUserOffset , size - ManagedOpenOrCreateUserOffset, true); //All ok, just move resources to the external mapped region final_region.swap(region); } BOOST_CATCH(...){ atomic_write32(patomic_word, CorruptedSegment); BOOST_RETHROW } BOOST_CATCH_END atomic_write32(patomic_word, InitializedSegment); } else{ atomic_write32(patomic_word, CorruptedSegment); throw interprocess_exception(error_info(corrupted_error)); } } BOOST_CATCH(...){ BOOST_TRY{ truncate_device<FileBased>(dev, 1u, file_like_t()); } BOOST_CATCH(...){ } BOOST_CATCH_END BOOST_RETHROW } BOOST_CATCH_END } template <class ConstructFunc> static void do_map_after_open ( DeviceAbstraction &dev, mapped_region &final_region , const void *addr, ConstructFunc construct_func , bool ronly, bool cow) { const usduration TimeoutSec(usduration_from_seconds(MaxInitializeTimeSec)); if(FileBased){ offset_t filesize = 0; spin_wait swait; //If a file device was used, the creator might be truncating the device, so wait //until the file size is enough to map the initial word ustime ustime_start = microsec_clock<ustime>::universal_time(); while(1){ if(!get_file_size(file_handle_from_mapping_handle(dev.get_mapping_handle()), filesize)){ error_info err = system_error_code(); throw interprocess_exception(err); } if (filesize != 0) break; else { //More than MaxZeroTruncateTimeSec seconds waiting to the creator //to minimally increase the size of the file: something bad has happened const usduration elapsed(microsec_clock<ustime>::universal_time() - ustime_start); if (elapsed > TimeoutSec){ throw interprocess_exception(error_info(corrupted_error)); } swait.yield(); } } //The creator detected an error creating the file and signalled it with size 1 if(filesize == 1){ throw interprocess_exception(error_info(corrupted_error)); } } mapped_region region(dev, ronly ? read_only : (cow ? copy_on_write : read_write), 0, 0, addr); boost::uint32_t *patomic_word = static_cast<boost::uint32_t*>(region.get_address()); boost::uint32_t value = atomic_read32(patomic_word); if (value != InitializedSegment){ ustime ustime_start = microsec_clock<ustime>::universal_time(); spin_wait swait; while ((value = atomic_read32(patomic_word)) != InitializedSegment){ if(value == CorruptedSegment){ throw interprocess_exception(error_info(corrupted_error)); } //More than MaxZeroTruncateTimeSec seconds waiting to the creator //to minimally increase the size of the file: something bad has happened const usduration elapsed(microsec_clock<ustime>::universal_time() - ustime_start); if (elapsed > TimeoutSec){ throw interprocess_exception(error_info(corrupted_error)); } swait.yield(); } //The size of the file might have grown while Uninitialized -> Initializing, so remap { mapped_region null_map; region.swap(null_map); } mapped_region final_size_map(dev, ronly ? read_only : (cow ? copy_on_write : read_write), 0, 0, addr); final_size_map.swap(region); } construct_func( static_cast<char*>(region.get_address()) + ManagedOpenOrCreateUserOffset , region.get_size() - ManagedOpenOrCreateUserOffset , false); //All ok, just move resources to the external mapped region final_region.swap(region); } template <class DeviceId, class ConstructFunc> inline void priv_open_or_create (create_enum_t type, const DeviceId & id, std::size_t size, mode_t mode, const void *addr, const permissions &perm, ConstructFunc construct_func) { if(type != DoOpen){ //Check if the requested size is enough to build the managed metadata const std::size_t func_min_size = construct_func.get_min_size(); if( (std::size_t(-1) - ManagedOpenOrCreateUserOffset) < func_min_size || size < (func_min_size + ManagedOpenOrCreateUserOffset) ){ throw interprocess_exception(error_info(size_error)); } //Check size can be represented by offset_t (used by truncate) if (!check_offset_t_size<FileBased>(size, file_like_t())){ throw interprocess_exception(error_info(size_error)); } } //Now create the device (file, shm file, etc.) DeviceAbstraction dev; (void)mode; bool created = false; bool ronly = false; bool cow = false; if(type == DoOpen){ DeviceAbstraction tmp(open_only, id, mode == read_write ? read_write : read_only); tmp.swap(dev); ronly = mode == read_only; cow = mode == copy_on_write; } else if(type == DoCreate){ create_device<FileBased>(dev, id, size, perm, file_like_t()); created = true; } else { //DoOpenOrCreate created = this->do_create_else_open(dev, id, size, perm); } if(created){ this->do_map_after_create(dev, m_mapped_region, size, addr, construct_func); } else{ this->do_map_after_open(dev, m_mapped_region, addr, construct_func, ronly, cow); } if(StoreDevice){ this->DevHolder::get_device() = boost::move(dev); } } friend void swap(managed_open_or_create_impl &left, managed_open_or_create_impl &right) { left.swap(right); } private: friend class interprocess_tester; void dont_close_on_destruction() { interprocess_tester::dont_close_on_destruction(m_mapped_region); } mapped_region m_mapped_region; }; } //namespace ipcdetail { } //namespace interprocess { } //namespace boost { #include <boost/interprocess/detail/config_end.hpp> #endif //#ifndef BOOST_INTERPROCESS_MANAGED_OPEN_OR_CREATE_IMPL