process/v1/handles.hpp

0001 // Copyright (c) 2019 Klemens D. Morgenstern
0002 //
0003 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0004 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0005
0006 #ifndef BOOST_PROCESS_HANDLES_HPP_
0007 #define BOOST_PROCESS_HANDLES_HPP_
0008
0009 /**
0010  * \file boost/process/handles.hpp
0011  *
0012  * Defines functions to obtain handles of the current process and limit the amount for inherited ones.
0013  */
0014
0015 #include <boost/process/v1/detail/config.hpp>
0016
0017 #if defined(BOOST_POSIX_API)
0018 #include <boost/process/v1/detail/posix/handles.hpp>
0019 #elif defined(BOOST_WINDOWS_API)
0020 #include <boost/process/v1/detail/windows/handles.hpp>
0021 #endif
0022
0023 #include <boost/process/v1/detail/used_handles.hpp>
0024
0025
0026 namespace boost
0027 {
0028 namespace this_process
0029 {
0030
0031 ///The native type for handles
0032 using native_handle_type = ::boost::process::v1::detail::api::native_handle_type;
0033
0034 /**
0035  * Get a snapshot of all handles of the process (i.e. file descriptors on posix and handles on windows) of the current process.
0036  *
0037  * \note This function might not work on certain posix systems.
0038  *
0039  * \note On Windows version older than windows 8 this function will iterate all the system handles, meaning it might be quite slow.
0040  *
0041  * \warning This functionality is utterly prone to race conditions, since other threads might open or close handles.
0042  *
0043  * \return The list of all open handles of the current process
0044  */
0045 inline std::vector <native_handle_type> get_handles()
0046 {
0047   return ::boost::process::v1::detail::api::get_handles();
0048 }
0049
0050
0051 /** \overload std::vector<native_handle_type> get_handles() */
0052 inline std::vector <native_handle_type> get_handles(std::error_code &ec)
0053 {
0054   return ::boost::process::v1::detail::api::get_handles(ec);
0055 }
0056
0057 /** Determines if a given handle is a a stream-handle, i.e. any handle that can be used with read and write functions.
0058  * Stream handles include pipes, regular files and sockets.
0059  *
0060  * \return Indicates if it's a stream handle.
0061  */
0062 inline bool is_stream_handle(native_handle_type handle)
0063 {
0064   return ::boost::process::v1::detail::api::is_stream_handle(handle);
0065 }
0066
0067
0068 /** \overload bool is_stream_handle(native_handle_type handle) */
0069 inline bool is_stream_handle(native_handle_type handle, std::error_code &ec)
0070 {
0071   return ::boost::process::v1::detail::api::is_stream_handle(handle, ec);
0072 }
0073
0074 }
0075 namespace process
0076 {
0077 BOOST_PROCESS_V1_INLINE
0078 namespace v1
0079 {
0080
0081 namespace detail
0082 {
0083
0084 using limit_handles_ = ::boost::process::v1::detail::api::limit_handles_;
0085
0086
0087 }
0088
0089 /**
0090  * The limit_handles property sets all properties to be inherited only explicitly. It closes all unused file-descriptors on posix after the fork and
0091  * removes the inherit flags on windows.
0092  *
0093  * \note This is executed after the fork on posix.
0094  *
0095  * \code{.cpp}
0096  * system("gcc", limit_handles);
0097  * \endcode
0098  *
0099  * Since limit also closes the standard handles unless they are explicitly redirected they can be ignored by `limit_handles` in the following way.
0100  *
0101  * \code{.cpp}
0102  * system("gcc", limit_handles.allowStd())
0103  * \endcode
0104  *
0105 */
0106 const static ::boost::process::v1::detail::api::limit_handles_ limit_handles;
0107
0108
0109 }
0110 }
0111 }
0112
0113 #endif //BOOST_PROCESS_HANDLES_HPP_