140 lines
3.8 KiB
C++
140 lines
3.8 KiB
C++
/*
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* \brief Utility to open a ROM session and locally attach its content
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* \author Norman Feske
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* \date 2012-01-09
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*/
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/*
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* Copyright (C) 2012-2017 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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#ifndef _INCLUDE__BASE__ATTACHED_ROM_DATASPACE_H_
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#define _INCLUDE__BASE__ATTACHED_ROM_DATASPACE_H_
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#include <util/reconstructible.h>
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#include <util/xml_node.h>
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#include <base/attached_dataspace.h>
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#include <rom_session/connection.h>
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namespace Genode { class Attached_rom_dataspace; }
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class Genode::Attached_rom_dataspace
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{
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private:
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Region_map &_rm;
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Rom_connection _rom;
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/*
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* A ROM module may change or disappear over the lifetime of a ROM
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* session. In contrast to the plain 'Attached_dataspace', which is
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* always be valid once constructed, a 'Attached_rom_dataspace' has
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* to handle the validity of the dataspace.
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*/
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Constructible<Attached_dataspace> _ds { };
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/**
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* Try to attach the ROM module, ignore invalid dataspaces
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*/
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void _try_attach()
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{
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/*
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* Normally, '_ds.construct()' would implicitly destruct an
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* existing dataspace upon re-construction. However, we have to
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* explicitly destruct the original dataspace prior calling
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* '_rom.dataspace()'.
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*
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* The ROM server may destroy the original dataspace when the
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* 'dataspace()' method is called. In this case, all existing
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* mappings of the dataspace will be flushed by core. A destruction
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* of 'Attached_dataspace' after this point will attempt to detach
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* the already flushed mappings, thereby producing error messages
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* at core.
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*/
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_ds.destruct();
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try { _ds.construct(_rm, _rom.dataspace()); }
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catch (Attached_dataspace::Invalid_dataspace) { }
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}
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public:
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/**
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* Constructor
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*
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* \throw Rom_connection::Rom_connection_failed
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* \throw Region_map::Region_conflict
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* \throw Region_map::Invalid_dataspace
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* \throw Out_of_ram
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* \throw Out_of_caps
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*/
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Attached_rom_dataspace(Env &env, char const *name)
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: _rm(env.rm()), _rom(env, name) { _try_attach(); }
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/**
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* Return capability of the used dataspace
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*/
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Dataspace_capability cap() const { return _ds->cap(); }
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template <typename T> T *local_addr() {
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return _ds->local_addr<T>(); }
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template <typename T> T const *local_addr() const {
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return _ds->local_addr<T const>(); }
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size_t size() const { return _ds.constructed() ? _ds->size() : 0; }
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/**
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* Register signal handler for ROM module changes
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*/
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void sigh(Signal_context_capability sigh) { _rom.sigh(sigh); }
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/**
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* Update ROM module content, re-attach if needed
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*/
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void update()
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{
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/*
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* If the dataspace is already attached and the update fits into
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* the existing dataspace, we can keep everything in place. The
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* dataspace content gets updated by the call of '_rom.update'.
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*/
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if (_ds.constructed() && _rom.update() == true)
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return;
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/*
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* If there was no valid dataspace attached beforehand or the
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* new data size exceeds the capacity of the existing dataspace,
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* replace the current dataspace by a new one.
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*/
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_try_attach();
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}
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/**
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* Return true of content is present
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*/
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bool valid() const { return _ds.constructed(); }
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/**
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* Return dataspace content as XML node
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*
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* This method always returns a valid XML node. It never throws an
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* exception. If the dataspace is invalid or does not contain properly
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* formatted XML, the returned XML node has the form "<empty/>".
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*/
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Xml_node xml() const
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{
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try {
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if (valid() && local_addr<void const>())
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return Xml_node(local_addr<char>(), size());
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} catch (Xml_node::Invalid_syntax) { }
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return Xml_node("<empty/>");
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}
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};
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#endif /* _INCLUDE__BASE__ATTACHED_ROM_DATASPACE_H_ */
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