110 lines
2.2 KiB
C++
110 lines
2.2 KiB
C++
/*
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* \brief Helper for handling the relationship between Noux processes
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* \author Norman Feske
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* \date 2012-02-25
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*/
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/*
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* Copyright (C) 2012-2013 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 General Public License version 2.
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*/
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#ifndef _NOUX__FAMILY_MEMBER_H_
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#define _NOUX__FAMILY_MEMBER_H_
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/* Genode includes */
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#include <util/list.h>
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#include <base/lock.h>
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namespace Noux {
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class Family_member : public List<Family_member>::Element
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{
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private:
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int const _pid;
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Lock _lock;
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List<Family_member> _list;
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Family_member * const _parent;
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bool _has_exited;
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int _exit_status;
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Semaphore _wait4_blocker;
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void _wakeup_wait4() { _wait4_blocker.up(); }
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public:
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Family_member(int pid, Family_member *parent)
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: _pid(pid), _parent(parent), _has_exited(false), _exit_status(0)
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{ }
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virtual ~Family_member() { }
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int pid() const { return _pid; }
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Family_member *parent() { return _parent; }
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int exit_status() const { return _exit_status; }
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/**
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* Called by the parent at creation time of the process
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*/
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void insert(Family_member *member)
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{
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Lock::Guard guard(_lock);
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_list.insert(member);
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}
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/**
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* Called by the parent from the return path of the wait4 syscall
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*/
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void remove(Family_member *member)
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{
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Lock::Guard guard(_lock);
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_list.remove(member);
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}
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/**
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* Tell the parent that we exited
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*/
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void wakeup_parent(int exit_status)
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{
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_exit_status = exit_status;
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_has_exited = true;
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if (_parent)
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_parent->_wakeup_wait4();
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}
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Family_member *poll4()
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{
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Lock::Guard guard(_lock);
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/* check if any of our children has exited */
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Family_member *curr = _list.first();
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for (; curr; curr = curr->next()) {
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if (curr->_has_exited)
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return curr;
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}
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return 0;
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}
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/**
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* Wait for the exit of any of our children
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*/
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Family_member *wait4()
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{
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for (;;) {
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Family_member *result = poll4();
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if (result)
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return result;
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_wait4_blocker.down();
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}
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}
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};
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}
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#endif /* _NOUX__FAMILY_MEMBER_H_ */
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