207 lines
5.1 KiB
C++
207 lines
5.1 KiB
C++
/*
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* \brief Provide a RAM dataspace as writable block device
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* \author Stefan Kalkowski
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* \author Sebastian Sumpf
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* \author Josef Soentgen
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* \date 2010-07-07
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*/
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/*
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* Copyright (C) 2010-2016 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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/* Genode includes */
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#include <base/attached_ram_dataspace.h>
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#include <base/attached_rom_dataspace.h>
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#include <base/component.h>
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#include <base/exception.h>
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#include <base/heap.h>
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#include <base/log.h>
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#include <block/component.h>
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#include <block/driver.h>
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using namespace Genode;
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class Ram_blk : public Block::Driver
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{
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private:
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Env &_env;
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Allocator *_alloc { nullptr };
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Attached_rom_dataspace *_rom_ds { nullptr };
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size_t _size;
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size_t _block_size;
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size_t _block_count;
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Attached_ram_dataspace _ram_ds;
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addr_t _ram_addr;
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void _io(Block::sector_t block_number,
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size_t block_count,
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char* buffer,
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Block::Packet_descriptor &packet,
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bool read)
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{
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/* sanity check block number */
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if (block_number + block_count > _block_count) {
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Genode::warning("requested blocks ", block_number, "-",
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block_number + block_count," out of range!");
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return;
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}
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size_t offset = (size_t) block_number * _block_size;
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size_t size = block_count * _block_size;
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void *src = read ? (void *)(_ram_addr + offset) : (void *)buffer;
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void *dst = read ? (void *)buffer : (void *)(_ram_addr + offset);
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/* copy file content to packet payload */
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memcpy(dst, src, size);
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ack_packet(packet);
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}
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public:
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/**
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* Construct populated RAM dataspace
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*/
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Ram_blk(Env &env, Allocator &alloc,
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const char *name, size_t block_size)
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:
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_env(env), _alloc(&alloc),
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_rom_ds(new (_alloc) Attached_rom_dataspace(_env, name)),
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_size(_rom_ds->size()),
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_block_size(block_size),
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_block_count(_size/_block_size),
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_ram_ds(_env.ram(), _env.rm(), _size),
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_ram_addr((addr_t)_ram_ds.local_addr<addr_t>())
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{
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/* populate backing store from file */
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memcpy(_ram_ds.local_addr<void>(), _rom_ds->local_addr<void>(), _size);
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}
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/**
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* Construct empty RAM dataspace
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*/
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Ram_blk(Env &env, size_t size, size_t block_size)
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:
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_env(env),
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_size(size),
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_block_size(block_size),
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_block_count(_size/_block_size),
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_ram_ds(_env.ram(), _env.rm(), _size),
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_ram_addr((addr_t)_ram_ds.local_addr<addr_t>())
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{ }
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~Ram_blk() { destroy(_alloc, _rom_ds); }
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/****************************
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** Block-driver interface **
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****************************/
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size_t block_size() { return _block_size; }
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Block::sector_t block_count() { return _block_count; }
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Block::Session::Operations ops()
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{
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Block::Session::Operations o;
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o.set_operation(Block::Packet_descriptor::READ);
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o.set_operation(Block::Packet_descriptor::WRITE);
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return o;
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}
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void read(Block::sector_t block_number,
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size_t block_count,
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char* buffer,
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Block::Packet_descriptor &packet)
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{
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_io(block_number, block_count, buffer, packet, true);
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}
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void write(Block::sector_t block_number,
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size_t block_count,
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const char * buffer,
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Block::Packet_descriptor &packet)
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{
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_io(block_number, block_count, const_cast<char *>(buffer), packet, false);
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}
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};
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struct Main
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{
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Env &env;
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Heap heap { env.ram(), env.rm() };
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Attached_rom_dataspace config_rom { env, "config" };
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struct Factory : Block::Driver_factory
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{
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Env &env;
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Allocator &alloc;
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bool use_file { false };
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char file[64];
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size_t size { 0 };
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size_t block_size { 512 };
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Factory(Env &env, Allocator &alloc,
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Xml_node config)
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: env(env), alloc(alloc)
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{
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use_file = config.has_attribute("file");
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if (use_file) {
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config.attribute("file").value(file, sizeof(file));
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} else {
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try {
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Genode::Number_of_bytes bytes;
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config.attribute("size").value(&bytes);
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size = bytes;
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} catch (...) {
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error("neither file nor size attribute specified");
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throw Exception();
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}
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}
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block_size = config.attribute_value("block_size", block_size);
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}
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Block::Driver *create()
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{
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try {
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if (use_file) {
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Genode::log("Creating RAM-basd block device populated by file='",
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Genode::Cstring(file), "' with block size ", block_size);
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return new (&alloc) Ram_blk(env, alloc, file, block_size);
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} else {
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Genode::log("Creating RAM-based block device with size ",
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size, " and block size ", block_size);
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return new (&alloc) Ram_blk(env, size, block_size);
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}
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} catch (...) {
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throw Root::Unavailable();
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}
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}
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void destroy(Block::Driver *driver) {
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Genode::destroy(&alloc, driver); }
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} factory { env, heap, config_rom.xml() };
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Block::Root root { env.ep(), heap, factory };
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Main(Env &env) : env(env)
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{
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env.parent().announce(env.ep().manage(root));
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}
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};
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void Component::construct(Genode::Env &env) { static Main server(env); }
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