// // ssl/detail/openssl_init.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // 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) // #ifndef BOOST_ASIO_SSL_DETAIL_OPENSSL_INIT_HPP #define BOOST_ASIO_SSL_DETAIL_OPENSSL_INIT_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include #include #include #include #include #include namespace boost { namespace asio { namespace ssl { namespace detail { class openssl_init_base : private noncopyable { protected: // Class that performs the actual initialisation. class do_init; // Helper function to manage a do_init singleton. The static instance of the // openssl_init object ensures that this function is always called before // main, and therefore before any other threads can get started. The do_init // instance must be static in this function to ensure that it gets // initialised before any other global objects try to use it. BOOST_ASIO_DECL static boost::asio::detail::shared_ptr instance(); #if !defined(SSL_OP_NO_COMPRESSION) \ && (OPENSSL_VERSION_NUMBER >= 0x00908000L) // Get an empty stack of compression methods, to be used when disabling // compression. BOOST_ASIO_DECL static STACK_OF(SSL_COMP)* get_null_compression_methods(); #endif // !defined(SSL_OP_NO_COMPRESSION) // && (OPENSSL_VERSION_NUMBER >= 0x00908000L) }; template class openssl_init : private openssl_init_base { public: // Constructor. openssl_init() : ref_(instance()) { using namespace std; // For memmove. // Ensure openssl_init::instance_ is linked in. openssl_init* tmp = &instance_; memmove(&tmp, &tmp, sizeof(openssl_init*)); } // Destructor. ~openssl_init() { } #if !defined(SSL_OP_NO_COMPRESSION) \ && (OPENSSL_VERSION_NUMBER >= 0x00908000L) using openssl_init_base::get_null_compression_methods; #endif // !defined(SSL_OP_NO_COMPRESSION) // && (OPENSSL_VERSION_NUMBER >= 0x00908000L) private: // Instance to force initialisation of openssl at global scope. static openssl_init instance_; // Reference to singleton do_init object to ensure that openssl does not get // cleaned up until the last user has finished with it. boost::asio::detail::shared_ptr ref_; }; template openssl_init openssl_init::instance_; } // namespace detail } // namespace ssl } // namespace asio } // namespace boost #include #if defined(BOOST_ASIO_HEADER_ONLY) # include #endif // defined(BOOST_ASIO_HEADER_ONLY) #endif // BOOST_ASIO_SSL_DETAIL_OPENSSL_INIT_HPP