235 lines
4.5 KiB
C++
235 lines
4.5 KiB
C++
/*
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* \brief Kernel backend for asynchronous inter-process communication
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* \author Martin Stein
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* \date 2012-11-30
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*/
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/*
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* Copyright (C) 2012-2019 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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/* core includes */
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#include <kernel/signal_receiver.h>
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#include <kernel/thread.h>
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using namespace Kernel;
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/********************
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** Signal_handler **
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********************/
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void Signal_handler::cancel_waiting()
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{
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if (_receiver) {
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_receiver->_handler_cancelled(*this);
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_receiver = 0;
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}
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}
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Signal_handler::Signal_handler(Thread &thread) : _thread { thread } { }
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Signal_handler::~Signal_handler() { cancel_waiting(); }
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/***************************
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** Signal_context_killer **
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***************************/
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void Signal_context_killer::cancel_waiting()
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{
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if (_context) { _context->_killer_cancelled(); }
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}
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Signal_context_killer::Signal_context_killer(Thread &thread)
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:
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_thread { thread }
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{ }
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Signal_context_killer::~Signal_context_killer() { cancel_waiting(); }
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/********************
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** Signal_context **
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********************/
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void Signal_context::_deliverable()
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{
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if (_submits) { _receiver._add_deliverable(*this); }
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}
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void Signal_context::_delivered()
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{
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_submits = 0;
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_ack = 0;
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}
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void Signal_context::_killer_cancelled() { _killer = 0; }
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bool Signal_context::can_submit(unsigned const n) const
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{
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if (_killed || _submits >= (unsigned)~0 - n) { return false; }
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return true;
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}
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void Signal_context::submit(unsigned const n)
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{
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if (_killed || _submits >= (unsigned)~0 - n) { return; }
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_submits += n;
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if (_ack) { _deliverable(); }
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}
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void Signal_context::ack()
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{
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if (_ack) { return; }
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if (!_killed) {
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_ack = 1;
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_deliverable();
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return;
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}
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if (_killer) {
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_killer->_context = 0;
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_killer->_thread.signal_context_kill_done();
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_killer = 0;
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}
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}
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bool Signal_context::can_kill() const
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{
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/* check if in a kill operation or already killed */
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if (_killed) {
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if (_ack) { return true; }
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return false;
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}
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return true;
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}
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void Signal_context::kill(Signal_context_killer &k)
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{
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/* check if in a kill operation or already killed */
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if (_killed) {
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return;
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}
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/* kill directly if there is no unacknowledged delivery */
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if (_ack) {
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_killed = 1;
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return;
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}
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/* wait for delivery acknowledgement */
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_killer = &k;
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_killed = 1;
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_killer->_context = this;
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_killer->_thread.signal_context_kill_pending();
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}
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Signal_context::~Signal_context()
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{
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if (_killer) { _killer->_thread.signal_context_kill_failed(); }
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_receiver._context_destructed(*this);
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}
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Signal_context::Signal_context(Signal_receiver & r, addr_t const imprint)
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: _receiver(r),
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_imprint(imprint)
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{
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r._add_context(*this);
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}
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/*********************
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** Signal_receiver **
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*********************/
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void Signal_receiver::_add_deliverable(Signal_context &c)
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{
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if (!c._deliver_fe.enqueued()) {
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_deliver.enqueue(c._deliver_fe);
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}
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_listen();
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}
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void Signal_receiver::_listen()
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{
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while (1)
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{
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/* check for deliverable signals and waiting handlers */
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if (_deliver.empty() || _handlers.empty()) { return; }
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/* create a signal data-object */
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typedef Genode::Signal_context * Signal_imprint;
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_deliver.dequeue([&] (Signal_context::Fifo_element &elem) {
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auto const context = &elem.object();
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Signal_imprint const imprint =
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reinterpret_cast<Signal_imprint>(context->_imprint);
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Signal::Data data(imprint, context->_submits);
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/* communicate signal data to handler */
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_handlers.dequeue([&] (Signal_handler::Fifo_element &elem) {
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auto const handler = &elem.object();
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handler->_receiver = nullptr;
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handler->_thread.signal_receive_signal(&data, sizeof(data));
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});
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context->_delivered();
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});
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}
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}
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void Signal_receiver::_context_destructed(Signal_context &c)
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{
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_contexts.remove(c._contexts_fe);
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if (!c._deliver_fe.enqueued()) { return; }
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_deliver.remove(c._deliver_fe);
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}
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void Signal_receiver::_handler_cancelled(Signal_handler &h) {
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_handlers.remove(h._handlers_fe); }
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void Signal_receiver::_add_context(Signal_context &c) {
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_contexts.enqueue(c._contexts_fe); }
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bool Signal_receiver::can_add_handler(Signal_handler const &h) const
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{
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if (h._receiver) { return false; }
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return true;
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}
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void Signal_receiver::add_handler(Signal_handler &h)
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{
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if (h._receiver) { return; }
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_handlers.enqueue(h._handlers_fe);
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h._receiver = this;
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h._thread.signal_wait_for_signal();
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_listen();
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}
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Signal_receiver::~Signal_receiver()
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{
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/* destruct all attached contexts */
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_contexts.dequeue_all([] (Signal_context::Fifo_element &elem) {
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elem.object().~Signal_context(); });
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}
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