ehmry/genode
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Simplify fs_rom internals

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Merge the 'Packet_handle' into the 'Rom_root' and use an Id_space to
match File_system handles to session objects rather than a list. This
avoids the need to override 'Root_component::_destroy_session'.

Fix #2833
This commit is contained in:
Ehmry - 2018-05-16 12:21:49 +02:00 committed by Christian Helmuth
parent b1b70e6c35
commit 6d5393dd31
1 changed files with 51 additions and 62 deletions
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113
repos/os/src/server/fs_rom/main.cc
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@ -32,12 +32,10 @@
namespace Fs_rom {
using namespace Genode;
struct Packet_handler;
class Rom_session_component;
class Rom_root;
typedef List<Rom_session_component> Sessions;
typedef Id_space<Rom_session_component> Sessions;
typedef File_system::Session_client::Tx::Source Tx_source;
}
@ -46,18 +44,19 @@ namespace Fs_rom {
/**
* A 'Rom_session_component' exports a single file of the file system
*/
class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
private Sessions::Element
class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>
{
private:
friend class List<Rom_session_component>;
friend class Packet_handler;
Env &_env;
Env &_env;
Sessions &_sessions;
File_system::Session &_fs;
Constructible<Sessions::Element> _watch_elem { };
enum { PATH_MAX_LEN = 512 };
typedef Genode::Path<PATH_MAX_LEN> Path;
@ -131,6 +130,8 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
while (true) {
try {
_watch_handle.construct(_fs.watch(watch_path.base()));
_watch_elem.construct(
*this, _sessions, Sessions::Id{_watch_handle->value});
_watching_file = at_the_file;
return;
}
@ -155,6 +156,7 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
void _close_watch_handle()
{
if (_watch_handle.constructed()) {
_watch_elem.destruct();
_fs.close(*_watch_handle);
_watch_handle.destruct();
}
@ -184,6 +186,8 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
parent_handle, file_name.base() + 1,
File_system::READ_ONLY, false);
Handle_guard file_guard(_fs, _file_handle);
Sessions::Element read_elem(
*this, _sessions, Sessions::Id{_file_handle.value});
/* ...but only for the lifetime of this procedure */
_file_seek = 0;
@ -288,10 +292,11 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
* creation time)
*/
Rom_session_component(Env &env,
Sessions &sessions,
File_system::Session &fs,
const char *file_path)
:
_env(env), _fs(fs),
_env(env), _sessions(sessions), _fs(fs),
_file_path(file_path),
_file_ds(env.ram(), env.rm(), 0) /* realloc later */
{
@ -344,17 +349,15 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
return _try_read_dataspace(UPDATE_ONLY); }
/**
* If packet corresponds to this session then process and return true.
*
* Called from the signal handler.
* Called by the packet signal handler.
*/
bool process_packet(File_system::Packet_descriptor const packet)
void process_packet(File_system::Packet_descriptor const packet)
{
switch (packet.operation()) {
case File_system::Packet_descriptor::CONTENT_CHANGED:
if (!(packet.handle() == *_watch_handle))
return false;
return;
if (!_watching_file) {
/* try and get closer to the file */
@ -366,70 +369,40 @@ class Fs_rom::Rom_session_component : public Rpc_object<Rom_session>,
_curr_version = Version { _curr_version.value + 1 };
_notify_client_about_new_version();
}
return true;
return;
case File_system::Packet_descriptor::READ: {
if (!(packet.handle() == _file_handle))
return false;
return;
if (packet.position() > _file_seek || _file_seek >= _file_size) {
error("bad packet seek position");
_file_ds.realloc(&_env.ram(), 0);
_file_seek = 0;
return true;
return;
}
size_t const n = min(packet.length(), _file_size - _file_seek);
memcpy(_file_ds.local_addr<char>()+_file_seek,
_fs.tx()->packet_content(packet), n);
_file_seek += n;
return true;
return;
}
case File_system::Packet_descriptor::WRITE:
warning("discarding strange WRITE acknowledgement");
return true;
return;
case File_system::Packet_descriptor::SYNC:
warning("discarding strange SYNC acknowledgement");
return true;
return;
case File_system::Packet_descriptor::READ_READY:
warning("discarding strange READ_READY acknowledgement");
return true;
return;
}
return false;
}
};
struct Fs_rom::Packet_handler : Io_signal_handler<Packet_handler>
{
Tx_source &source;
/* list of open sessions */
Sessions sessions { };
void handle_packets()
{
while (source.ack_avail()) {
File_system::Packet_descriptor pack = source.get_acked_packet();
for (Rom_session_component *session = sessions.first();
session; session = session->next())
{
if (session->process_packet(pack))
break;
}
source.release_packet(pack);
}
}
Packet_handler(Entrypoint &ep, Tx_source &source)
:
Io_signal_handler<Packet_handler>(
ep, *this, &Packet_handler::handle_packets),
source(source)
{ }
};
class Fs_rom::Rom_root : public Root_component<Fs_rom::Rom_session_component>
{
@ -437,12 +410,37 @@ class Fs_rom::Rom_root : public Root_component<Fs_rom::Rom_session_component>
Env &_env;
Heap _heap { _env.ram(), _env.rm() };
Sessions _sessions { };
Allocator_avl _fs_tx_block_alloc { &_heap };
/* open file-system session */
File_system::Connection _fs { _env, _fs_tx_block_alloc };
Packet_handler _packet_handler { _env.ep(), *_fs.tx() };
Io_signal_handler<Rom_root> _packet_handler {
_env.ep(), *this, &Rom_root::_handle_packets };
void _handle_packets()
{
Tx_source &source = *_fs.tx();
while (source.ack_avail()) {
File_system::Packet_descriptor pkt = source.get_acked_packet();
/* sessions are indexed in space by watch and read handles */
auto const apply_fn = [pkt] (Rom_session_component &session) {
session.process_packet(pkt); };
try { _sessions.apply<Rom_session_component&>(
Sessions::Id{pkt.handle().value}, apply_fn); }
/* packet handle closed while packet in flight */
catch (Sessions::Unknown_id) { }
source.release_packet(pkt);
}
}
Rom_session_component *_create_session(const char *args) override
{
@ -450,17 +448,8 @@ class Fs_rom::Rom_root : public Root_component<Fs_rom::Rom_session_component>
Session_label const module_name = label.last_element();
/* create new session for the requested file */
Rom_session_component *session = new (md_alloc())
Rom_session_component(_env, _fs, module_name.string());
_packet_handler.sessions.insert(session);
return session;
}
void _destroy_session(Rom_session_component *session) override
{
_packet_handler.sessions.remove(session);
Genode::destroy(md_alloc(), session);
return new (md_alloc())
Rom_session_component(_env, _sessions, _fs, module_name.string());
}
public: