145 lines
3.4 KiB
C++
145 lines
3.4 KiB
C++
/*
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* \brief Registry of ROM modules
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* \author Norman Feske
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* \date 2014-01-11
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*/
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/*
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* Copyright (C) 2014-2017 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 _ROM_REGISTRY_H_
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#define _ROM_REGISTRY_H_
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/* Genode includes */
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#include <report_rom/rom_registry.h>
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#include <os/session_policy.h>
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namespace Rom { struct Registry; }
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struct Rom::Registry : Registry_for_reader, Registry_for_writer, Genode::Noncopyable
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{
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private:
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Genode::Allocator &_md_alloc;
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Genode::Ram_allocator &_ram;
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Genode::Region_map &_rm;
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Reader &_reader;
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Module_list _modules { };
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struct Read_write_policy : Module::Read_policy, Module::Write_policy
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{
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bool read_permitted(Module const &,
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Writer const &,
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Reader const &) const override
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{
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/*
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* The pointer application is always allowed to read the ROM content.
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*/
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return true;
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}
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bool write_permitted(Module const &, Writer const &) const override
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{
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/*
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* Because the report-session label is used as the module name
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* for the writer, each report session refers to a distinct
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* module. Report client can write to their respective modules
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* at any time.
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*/
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return true;
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}
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} _read_write_policy { };
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Module &_lookup(Module::Name const name, bool create_if_not_found)
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{
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for (Module *m = _modules.first(); m; m = m->next())
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if (m->_has_name(name))
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return *m;
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if (!create_if_not_found)
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throw Genode::Service_denied();
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/* module does not exist yet, create one */
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Genode::Session_label session_label(name);
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if (session_label.last_element() != "shape")
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Genode::warning("received unexpected report with label '",
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session_label, "'");
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/* XXX proper accounting for the used memory is missing */
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/* XXX if we run out of memory, the server will abort */
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Module * const module = new (&_md_alloc)
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Module(_ram, _rm, session_label.prefix(), _read_write_policy,
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_read_write_policy);
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_modules.insert(module);
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return *module;
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}
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void _try_to_destroy(Module const &module)
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{
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if (module._in_use())
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return;
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_modules.remove(&module);
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Genode::destroy(&_md_alloc, const_cast<Module *>(&module));
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}
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public:
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Registry(Genode::Allocator &md_alloc,
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Genode::Ram_allocator &ram, Genode::Region_map &rm,
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Reader &reader)
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:
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_md_alloc(md_alloc), _ram(ram), _rm(rm), _reader(reader)
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{ }
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Module &lookup(Writer &writer, Module::Name const &name) override
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{
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Module &module = _lookup(name, true);
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module._register(writer);
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/*
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* Enforce invariant that each module can have only one writer at a
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* time.
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*/
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if (module._num_writers() > 1) {
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release(writer, module);
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throw Genode::Service_denied();
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}
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module._register(_reader);
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return module;
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}
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void release(Writer &writer, Module &module) override
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{
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module._unregister(_reader);
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module._unregister(writer);
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_try_to_destroy(module);
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}
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Readable_module &lookup(Reader &, Module::Name const &rom_label) override
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{
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return _lookup(rom_label, false);
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}
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void release(Reader &, Readable_module &module) override
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{
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_try_to_destroy(static_cast<Module&>(module));
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}
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};
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#endif /* _ROM_REGISTRY_H_ */
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