6b289a1423
This patch replaces the former prominent use of pointers by references wherever feasible. This has the following benefits: * The contract between caller and callee becomes more obvious. When passing a reference, the contract says that the argument cannot be a null pointer. The caller is responsible to ensure that. Therefore, the use of reference eliminates the need to add defensive null-pointer checks at the callee site, which sometimes merely exist to be on the safe side. The bottom line is that the code becomes easier to follow. * Reference members must be initialized via an object initializer, which promotes a programming style that avoids intermediate object- construction states. Within core, there are still a few pointers as member variables left though. E.g., caused by the late association of 'Platform_thread' objects with their 'Platform_pd' objects. * If no pointers are present as member variables, we don't need to manually provide declarations of a private copy constructor and an assignment operator to avoid -Weffc++ errors "class ... has pointer data members [-Werror=effc++]". This patch also changes a few system bindings on NOVA and Fiasco.OC, e.g., the return value of the global 'cap_map' accessor has become a reference. Hence, the patch touches a few places outside of core. Fixes #3135
143 lines
3.9 KiB
C++
143 lines
3.9 KiB
C++
/*
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* \brief Core-internal dataspace representation on Linux
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* \author Norman Feske
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* \date 2006-05-19
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*
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* On Linux userland, we do not deal with physical memory. Instead,
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* we create a file for each dataspace that is to be mmapped.
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* Therefore, the allocator is not really used for allocating
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* memory but only as a container for quota.
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*/
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/*
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* Copyright (C) 2006-2017 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 _CORE__INCLUDE__DATASPACE_COMPONENT_H_
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#define _CORE__INCLUDE__DATASPACE_COMPONENT_H_
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#include <linux_dataspace/linux_dataspace.h>
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#include <util/string.h>
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#include <util/misc_math.h>
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#include <base/rpc_server.h>
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/* base-internal includes */
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#include <base/internal/capability_space_tpl.h>
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namespace Genode {
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/**
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* Deriving classes can own a dataspace to implement conditional behavior
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*/
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class Dataspace_owner : Interface { };
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class Dataspace_component : public Rpc_object<Linux_dataspace>
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{
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private:
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Filename _fname { }; /* filename for mmap */
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size_t const _size; /* size of dataspace in bytes */
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addr_t const _addr; /* meaningless on linux */
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int _fd { -1 }; /* file descriptor */
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bool const _writable; /* false if read-only */
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/* Holds the dataspace owner if a distinction between owner and
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* others is necessary on the dataspace, otherwise it is 0 */
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Dataspace_owner const * const _owner;
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static Filename _file_name(const char *args);
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size_t _file_size();
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/*
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* Noncopyable
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*/
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Dataspace_component(Dataspace_component const &);
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Dataspace_component &operator = (Dataspace_component const &);
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public:
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/**
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* Constructor
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*/
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Dataspace_component(size_t size, addr_t addr,
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Cache_attribute, bool writable,
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Dataspace_owner * owner)
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: _size(size), _addr(addr), _fd(-1), _writable(writable),
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_owner(owner) { }
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/**
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* Default constructor returns invalid dataspace
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*/
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Dataspace_component()
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: _size(0), _addr(0), _fd(-1), _writable(false), _owner(nullptr) { }
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/**
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* This constructor is only provided for compatibility
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* reasons and should not be used.
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*/
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Dataspace_component(size_t size, addr_t, addr_t phys_addr,
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Cache_attribute, bool, Dataspace_owner *_owner)
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:
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_size(size), _addr(phys_addr), _fd(-1), _writable(false),
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_owner(_owner)
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{
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warning("Should only be used for IOMEM and not within Linux.");
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_fname.buf[0] = 0;
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}
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/**
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* This constructor is especially used for ROM dataspaces
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*
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* \param args session parameters containing 'filename' key/value
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*/
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Dataspace_component(const char *args);
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/**
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* Assign file descriptor to dataspace
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*
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* The file descriptor assigned to the dataspace will be enable
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* processes outside of core to mmap the dataspace.
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*/
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void fd(int fd) { _fd = fd; }
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/**
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* Check if dataspace is owned by a specified object
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*/
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bool owner(Dataspace_owner const &o) const { return _owner == &o; }
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/**
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* Detach dataspace from all rm sessions.
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*/
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void detach_from_rm_sessions() { }
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/*************************
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** Dataspace interface **
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*************************/
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size_t size() override { return _size; }
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addr_t phys_addr() override { return _addr; }
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bool writable() override { return _writable; }
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/****************************************
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** Linux-specific dataspace interface **
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****************************************/
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Filename fname() { return _fname; }
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Untyped_capability fd()
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{
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Untyped_capability fd_cap =
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Capability_space::import(Rpc_destination(_fd), Rpc_obj_key());
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return fd_cap;
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}
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};
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}
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#endif /* _CORE__INCLUDE__DATASPACE_COMPONENT_H_ */
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