整理

include/boost/process/v1/detail/posix/sigchld_service.hpp

@@ -0,0 +1,152 @@
+// Copyright (c) 2017 Klemens D. Morgenstern
+//
+// 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_PROCESS_DETAIL_POSIX_SIGCHLD_SERVICE_HPP_
+#define BOOST_PROCESS_DETAIL_POSIX_SIGCHLD_SERVICE_HPP_
+
+#include <boost/asio/bind_executor.hpp>
+#include <boost/asio/dispatch.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/asio/consign.hpp>
+#include <boost/asio/append.hpp>
+#include <boost/asio/signal_set.hpp>
+#include <boost/asio/strand.hpp>
+#include <boost/optional.hpp>
+#include <signal.h>
+#include <functional>
+#include <sys/wait.h>
+#include <list>
+
+namespace boost { namespace process { BOOST_PROCESS_V1_INLINE namespace v1 { namespace detail { namespace posix {
+
+class sigchld_service : public boost::asio::detail::service_base<sigchld_service>
+{
+    boost::asio::strand<boost::asio::io_context::executor_type> _strand{get_io_context().get_executor()};
+    boost::asio::signal_set _signal_set{get_io_context(), SIGCHLD};
+
+    std::list<std::pair<::pid_t, std::function<void(int, std::error_code)>>> _receivers;
+    inline void _handle_signal(const boost::system::error_code & ec);
+
+    struct initiate_async_wait_op
+    {
+        sigchld_service * self;
+        template<typename Initiation>
+        void operator()(Initiation && init, ::pid_t pid)
+        {
+            // check if the child actually is running first
+            int status;
+            auto pid_res = ::waitpid(pid, &status, WNOHANG);
+            if (pid_res < 0)
+            {
+                auto ec = get_last_error();
+                boost::asio::post(
+                        self->_strand,
+                        asio::append(std::forward<Initiation>(init), pid_res, ec));
+            }
+            else if ((pid_res == pid) && (WIFEXITED(status) || WIFSIGNALED(status)))
+                boost::asio::post(
+                        self->_strand,
+                        boost::asio::append(std::forward<Initiation>(init), status, std::error_code{}));
+            else //still running
+            {
+                sigchld_service * self_ = self;
+                if (self->_receivers.empty())
+                    self->_signal_set.async_wait(
+                        boost::asio::bind_executor(
+                            self->_strand,
+                            [self_](const boost::system::error_code &ec, int)
+                            {
+                                self_->_handle_signal(ec);
+                            }));
+                self->_receivers.emplace_back(pid, init);
+            }
+        }
+    };
+
+public:
+    sigchld_service(boost::asio::io_context & io_context)
+        : boost::asio::detail::service_base<sigchld_service>(io_context)
+    {
+    }
+
+    template <typename SignalHandler>
+    BOOST_ASIO_INITFN_RESULT_TYPE(SignalHandler,
+        void (int, std::error_code))
+    async_wait(::pid_t pid, SignalHandler && handler)
+    {
+        return boost::asio::async_initiate<
+            SignalHandler,
+            void(int, std::error_code)>(
+                initiate_async_wait_op{this}, handler, pid);
+    }
+    void shutdown() override
+    {
+        _receivers.clear();
+    }
+
+    void cancel()
+    {
+        _signal_set.cancel();
+    }
+    void cancel(boost::system::error_code & ec)
+    {
+        _signal_set.cancel(ec);
+    }
+};
+
+
+void sigchld_service::_handle_signal(const boost::system::error_code & ec)
+{
+    std::error_code ec_{ec.value(), std::system_category()};
+
+    if (ec_)
+    {
+        for (auto & r : _receivers)
+            r.second(-1, ec_);
+        return;
+    }
+
+    for (auto & r : _receivers) {
+        int status;
+        int pid = ::waitpid(r.first, &status, WNOHANG);
+        if (pid < 0) {
+            // error (eg: the process no longer exists)
+            r.second(-1, get_last_error());
+            r.first = 0; // mark for deletion
+        } else if (pid == r.first) {
+            r.second(status, ec_);
+            r.first = 0; // mark for deletion
+        }
+        // otherwise the process is still around
+    }
+
+    _receivers.erase(std::remove_if(_receivers.begin(), _receivers.end(),
+            [](const std::pair<::pid_t, std::function<void(int, std::error_code)>> & p)
+            {
+                return p.first == 0;
+            }),
+            _receivers.end());
+
+    if (!_receivers.empty())
+    {
+        _signal_set.async_wait(
+            [this](const boost::system::error_code & ec, int)
+            {
+                boost::asio::post(_strand, [this, ec]{this->_handle_signal(ec);});
+            });
+    }
+}
+
+
+}
+}
+}
+}
+}
+
+
+
+#endif