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eeb2d95b1f
Until now, block drivers had to deal with a pointer to the client session component, e.g.: to acknowledge block packets already processed. When a session was closed, the driver object wasn't informed explicitly, which leads to defensive programming, or lastly to a race-condition in test-blk-srv. To prevent from this class of errors, the pointer is now private to the generic block driver base class, and not accessible to the concrete driver implementation. Moreover, the driver gets explicitly informed when a session got invalidated. Ref #113
113 lines
2.5 KiB
C++
113 lines
2.5 KiB
C++
/*
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* \brief Block interface for HTTP block driver
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* \author Sebastian Sumpf <sebastian.sumpf@genode-labs.com>
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* \author Stefan Kalkowski <stefan.kalkowski@genode-labs.com>
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* \date 2010-08-24
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*/
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/*
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* Copyright (C) 2010-2013 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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/* Genode includes */
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#include <cap_session/connection.h>
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#include <block/component.h>
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#include <os/config.h>
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/* local includes */
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#include "http.h"
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using namespace Genode;
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class Driver : public Block::Driver
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{
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private:
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size_t _block_size;
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Http _http;
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public:
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Driver(size_t block_size, char *uri)
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: _block_size(block_size), _http(uri) {}
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/*******************************
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** Block::Driver interface **
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*******************************/
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Genode::size_t block_size() { return _block_size; }
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Block::sector_t block_count() { return _http.file_size() / _block_size; }
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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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return o;
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}
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void read(Block::sector_t block_nr,
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Genode::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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_http.cmd_get(block_nr * _block_size, block_count * _block_size,
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(addr_t)buffer);
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ack_packet(packet);
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}
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};
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class Factory : public Block::Driver_factory
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{
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private:
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char _uri[64];
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size_t _blk_sz;
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public:
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Factory() : _blk_sz(512)
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{
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try {
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config()->xml_node().attribute("uri").value(_uri, sizeof(_uri));
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config()->xml_node().attribute("block_size").value(&_blk_sz);
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}
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catch (...) { }
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PINF("Using file=%s as device with block size %zx.", _uri, _blk_sz);
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}
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Block::Driver *create() {
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return new (env()->heap()) Driver(_blk_sz, _uri); }
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void destroy(Block::Driver *driver) {
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Genode::destroy(env()->heap(), driver); }
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};
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struct Main
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{
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Server::Entrypoint &ep;
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struct Factory factory;
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Block::Root root;
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Main(Server::Entrypoint &ep)
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: ep(ep), root(ep, Genode::env()->heap(), factory) {
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Genode::env()->parent()->announce(ep.manage(root)); }
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};
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/************
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** Server **
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************/
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namespace Server {
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char const *name() { return "http_blk_ep"; }
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size_t stack_size() { return 2*1024*sizeof(long); }
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void construct(Entrypoint &ep) { static Main server(ep); }
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}
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