1 files changed, 129 insertions, 0 deletions
diff --git a/src/lib/asiolink/io_service_signal.cc b/src/lib/asiolink/io_service_signal.cc
new file mode 100644
index 0000000..ea10103
--- /dev/null
+++ b/src/lib/asiolink/io_service_signal.cc
@@ -0,0 +1,129 @@
+// Copyright (C) 2020-2021 Internet Systems Consortium, Inc. ("ISC")
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#include <config.h>
+
+#include <asiolink/io_service_signal.h>
+#include <exceptions/exceptions.h>
+
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/noncopyable.hpp>
+#include <boost/asio/signal_set.hpp>
+#include <functional>
+
+namespace ph = std::placeholders;
+
+namespace isc {
+namespace asiolink {
+
+/// @brief Implementation class of IOSignalSet.
+class IOSignalSetImpl : public boost::enable_shared_from_this<IOSignalSetImpl>,
+                        public boost::noncopyable {
+public:
+    /// @brief Constructor.
+    ///
+    /// @param io_service the process IO service.
+    /// @param handler the signal handler.
+    IOSignalSetImpl(IOServicePtr io_service, IOSignalHandler handler);
+
+    /// @brief Destructor.
+    ~IOSignalSetImpl() = default;
+
+    /// @brief Install the callback on the IO service queue.
+    void install();
+
+    /// @brief Add a signal to the ASIO signal set.
+    ///
+    /// @param signum the signal number.
+    void add(int signum);
+
+    /// @brief Remove a signal from the ASIO signal set.
+    ///
+    /// @param signum the signal number.
+    void remove(int signum);
+
+private:
+    /// @brief Extends the lifetime of IOService to avoid heap-use-after-free.
+    IOServicePtr io_service_;
+
+    /// @brief the ASIO signal set.
+    boost::asio::signal_set signal_set_;
+
+    /// @brief the signal handler.
+    IOSignalHandler handler_;
+
+    /// @brief the callback (called on cancel or received signal).
+    ///
+    /// The callback is installed on the IO service queue and calls
+    /// the handler if the operation was not aborted.
+    void callback(const boost::system::error_code& ec, int signum);
+};
+
+IOSignalSetImpl::IOSignalSetImpl(IOServicePtr io_service,
+                                 IOSignalHandler handler)
+    : io_service_(io_service),
+      signal_set_(io_service_->get_io_service()),
+      handler_(handler) {
+}
+
+void
+IOSignalSetImpl::callback(const boost::system::error_code& ec, int signum) {
+    if (ec && ec.value() == boost::asio::error::operation_aborted) {
+        return;
+    }
+    install();
+    if (!ec && (signum > 0)) {
+        try {
+            handler_(signum);
+        } catch (const std::exception& ex) {
+        }
+    }
+}
+
+void
+IOSignalSetImpl::install() {
+    signal_set_.async_wait(std::bind(&IOSignalSetImpl::callback,
+                                     shared_from_this(), ph::_1, ph::_2));
+}
+
+void
+IOSignalSetImpl::add(int signum) {
+    try {
+        signal_set_.add(signum);
+    } catch (const boost::system::system_error& ex) {
+        isc_throw(isc::Unexpected,
+                  "Failed to add signal " << signum << ": " << ex.what());
+    }
+}
+
+void
+IOSignalSetImpl::remove(int signum) {
+    try {
+        signal_set_.remove(signum);
+    } catch (const boost::system::system_error& ex) {
+        isc_throw(isc::Unexpected,
+                  "Failed to remove signal " << signum << ": " << ex.what());
+    }
+}
+
+IOSignalSet::IOSignalSet(IOServicePtr io_service, IOSignalHandler handler) :
+    impl_(new IOSignalSetImpl(io_service, handler)) {
+    // It can throw but the error is fatal...
+    impl_->install();
+}
+
+void
+IOSignalSet::add(int signum) {
+    impl_->add(signum);
+}
+
+void
+IOSignalSet::remove(int signum) {
+    impl_->remove(signum);
+}
+
+} // namespace asiolink
+} // namespace isc