110 lines
3.2 KiB
C++
110 lines
3.2 KiB
C++
// Copyright (c) 2022 Klemens D. Morgenstern
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_PROCESS_V2_POSIX_BIND_FD_HPP
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#define BOOST_PROCESS_V2_POSIX_BIND_FD_HPP
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#include <boost/process/v2/detail/config.hpp>
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#include <boost/process/v2/default_launcher.hpp>
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#include <fcntl.h>
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BOOST_PROCESS_V2_BEGIN_NAMESPACE
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namespace posix
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{
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/// Utility class to bind a file descriptor to an explicit file descriptor for the child process.
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struct bind_fd
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{
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int target;
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int fd;
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bool fd_needs_closing{false};
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~bind_fd()
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{
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if (fd_needs_closing)
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::close(fd);
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}
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bind_fd() = delete;
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/// Inherit file descriptor with the same value.
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/**
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* This will pass descriptor 42 as 42 to the child process:
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* @code
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* process p{"test", {}, posix::bind_fd(42)};
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* @endcode
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*/
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bind_fd(int target) : target(target), fd(target) {}
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/// Inherit an asio io-object as a given file descriptor to the child process.
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/**
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* This will pass the tcp::socket, as 42 to the child process:
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* @code
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* extern tcp::socket sock;
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* process p{"test", {}, posix::bind_fd(42, sock)};
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* @endcode
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*/
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template<typename Stream>
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bind_fd(int target, Stream && str, decltype(std::declval<Stream>().native_handle()) = -1)
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: bind_fd(target, str.native_handle())
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{}
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/// Inherit a `FILE` as a given file descriptor to the child process.
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/**
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* This will pass the given `FILE*`, as 42 to the child process:
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* @code
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* process p{"test", {}, posix::bind_fd(42, stderr)};
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* @endcode
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*/
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bind_fd(int target, FILE * f) : bind_fd(target, fileno(f)) {}
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/// Inherit a file descriptor with as a differnet value.
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/**
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* This will pass 24 as 42 to the child process:
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* @code
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* process p{"test", {}, posix::bind_fd(42, 24)};
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* @endcode
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*/
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bind_fd(int target, int fd) : target(target), fd(fd) {}
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/// Inherit a null device as a set descriptor.
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/**
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* This will pass 24 as 42 to the child process:
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* @code
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* process p{"test", {}, posix::bind_fd(42, nullptr)};
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* @endcode
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*/
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bind_fd(int target, std::nullptr_t) : bind_fd(target, filesystem::path("/dev/null")) {}
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/// Inherit a newly openedfile as a set descriptor.
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/**
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* This will pass 24 as 42 to the child process:
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* @code
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* process p{"test", {}, posix::bind_fd(42, "extra-output.txt")};
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* @endcode
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*/
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bind_fd(int target, const filesystem::path & pth, int flags = O_RDWR | O_CREAT)
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: target(target), fd(::open(pth.c_str(), flags, 0660)), fd_needs_closing(true)
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{
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}
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/// Implementation of the initialization function.
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error_code on_exec_setup(posix::default_launcher & launcher, const filesystem::path &, const char * const *)
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{
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if (::dup2(fd, target) == -1)
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return error_code(errno, system_category());
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launcher.fd_whitelist.push_back(target);
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return error_code ();
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}
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};
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}
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BOOST_PROCESS_V2_END_NAMESPACE
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#endif //BOOST_PROCESS_V2_POSIX_BIND_FD_HPP
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