genode/repos/base/include/parent/parent.h
2017-05-31 13:16:21 +02:00

354 lines
12 KiB
C++

/*
* \brief Parent interface
* \author Norman Feske
* \date 2006-05-10
*/
/*
* Copyright (C) 2006-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__PARENT__PARENT_H_
#define _INCLUDE__PARENT__PARENT_H_
#include <base/exception.h>
#include <base/rpc.h>
#include <base/rpc_args.h>
#include <base/thread.h>
#include <base/id_space.h>
#include <session/capability.h>
#include <root/capability.h>
namespace Genode {
class Session_state;
class Parent;
}
class Genode::Parent
{
private:
/**
* Recursively announce inherited service interfaces
*
* At compile time, the 'ROOT' type is inspected for the presence
* of the 'Rpc_inherited_interface' type in the corresponding
* session interface. If present, the session type gets announced.
* This works recursively.
*/
template <typename ROOT>
void _announce_base(Capability<ROOT> const &, Meta::Bool_to_type<false> *) { }
/*
* This overload gets selected if the ROOT interface corresponds to
* an inherited session type.
*/
template <typename ROOT>
inline void _announce_base(Capability<ROOT> const &, Meta::Bool_to_type<true> *);
public:
typedef Rpc_in_buffer<64> Service_name;
typedef Rpc_in_buffer<160> Session_args;
typedef Rpc_in_buffer<160> Upgrade_args;
struct Client { typedef Id_space<Client>::Id Id; };
struct Server { typedef Id_space<Server>::Id Id; };
/**
* Predefined session IDs corresponding to the environment sessions
* created by the parent at the component-construction time
*/
struct Env
{
static Client::Id pd() { return { 1 }; }
static Client::Id cpu() { return { 2 }; }
static Client::Id log() { return { 3 }; }
static Client::Id binary() { return { 4 }; }
static Client::Id linker() { return { 5 }; }
static Client::Id last() { return { 5 }; }
/**
* True if session ID refers to an environment session
*/
static bool session_id(Client::Id id) {
return id.value >= 1 && id.value <= last().value; }
};
/**
* Use 'String' instead of 'Rpc_in_buffer' because 'Resource_args'
* is used as both in and out parameter.
*/
typedef String<160> Resource_args;
virtual ~Parent() { }
/**
* Tell parent to exit the program
*/
virtual void exit(int exit_value) = 0;
/**
* Announce service to the parent
*/
virtual void announce(Service_name const &service_name) = 0;
/**
* Emulation of the original synchronous root interface
*
* This function transparently spawns a proxy "root" entrypoint that
* dispatches asynchronous session-management operations (as issued
* by the parent) to the local root interfaces via component-local
* RPC calls.
*
* The function solely exists for API compatibility.
*/
static void announce(Service_name const &service_name,
Root_capability service_root);
/**
* Announce service to the parent
*
* \param service_root root capability
*
* The type of the specified 'service_root' capability match with
* an interface that provides a 'Session_type' type (i.e., a
* 'Typed_root' interface). This 'Session_type' is expected to
* host a class function called 'service_name' returning the
* name of the provided interface as null-terminated string.
*/
template <typename ROOT_INTERFACE>
void announce(Capability<ROOT_INTERFACE> const &service_root)
{
typedef typename ROOT_INTERFACE::Session_type Session;
announce(Session::service_name(), service_root);
/*
* Announce inherited session types
*
* Select the overload based on the presence of the type
* 'Rpc_inherited_interface' within the session type.
*/
_announce_base(service_root,
(Meta::Bool_to_type<Rpc_interface_is_inherited<Session>::VALUE> *)0);
}
/**
* Register signal handler for session notifications
*/
virtual void session_sigh(Signal_context_capability) = 0;
/**
* Create session to a service
*
* \param id client-side ID of new session
* \param service_name name of the requested interface
* \param args session constructor arguments
* \param affinity preferred CPU affinity for the session
*
* \throw Service_denied parent denies session request
* \throw Insufficient_cap_quota donated cap quota does not suffice
* \throw Insufficient_ram_quota donated RAM quota does not suffice
* \throw Out_of_caps session CAP quota exceeds our resources
* \throw Out_of_ram session RAM quota exceeds our resources
*
* \return session capability if the new session is immediately
* available, or an invalid capability
*
* If the returned capability is invalid, the request is pending at the
* server. The parent delivers a signal to the handler as registered
* via 'session_sigh' once the server responded to the request. Now the
* session capability can be picked up by calling 'session_cap'.
*/
virtual Session_capability session(Client::Id id,
Service_name const &service_name,
Session_args const &args,
Affinity const &affinity = Affinity()) = 0;
/**
* Request session capability
*
* \throw Service_denied
* \throw Insufficient_cap_quota
* \throw Insufficient_ram_quota
*
* See 'session' for more documentation.
*
* In the exception case, the parent implicitly closes the session.
*/
virtual Session_capability session_cap(Client::Id id) = 0;
enum Upgrade_result { UPGRADE_DONE, UPGRADE_PENDING };
/**
* Transfer our quota to the server that provides the specified session
*
* \param id ID of recipient session
* \param args description of the amount of quota to transfer
*
* \throw Out_of_caps
* \throw Out_of_ram
*
* The 'args' argument has the same principle format as the 'args'
* argument of the 'session' operation.
*/
virtual Upgrade_result upgrade(Client::Id to_session,
Upgrade_args const &args) = 0;
enum Close_result { CLOSE_DONE, CLOSE_PENDING };
/**
* Close session
*/
virtual Close_result close(Client::Id) = 0;
/*
* Interface for providing services
*/
enum Session_response { SESSION_OK, SESSION_CLOSED, SERVICE_DENIED,
INSUFFICIENT_RAM_QUOTA, INSUFFICIENT_CAP_QUOTA };
/**
* Set state of a session provided by the child service
*/
virtual void session_response(Server::Id, Session_response) = 0;
/**
* Deliver capability for a new session provided by the child service
*/
virtual void deliver_session_cap(Server::Id, Session_capability) = 0;
/*
* Dynamic resource balancing
*/
/**
* Provide thread_cap of main thread
*/
virtual Thread_capability main_thread_cap() const = 0;
/**
* Register signal handler for resource notifications
*/
virtual void resource_avail_sigh(Signal_context_capability sigh) = 0;
/**
* Request additional resources
*
* By invoking this method, a component is able to inform its
* parent about the need for additional resources. The argument
* string contains a resource description in the same format as
* used for session-construction arguments. In particular, for
* requesting additional RAM quota, the argument looks like
* "ram_quota=<amount>" where 'amount' is the amount of additional
* resources expected from the parent. If the parent complies with
* the request, it submits a resource-available signal to the
* handler registered via 'resource_avail_sigh()'. On the reception
* of such a signal, the component can re-evaluate its resource quota
* and resume execution.
*/
virtual void resource_request(Resource_args const &args) = 0;
/**
* Register signal handler for resource yield notifications
*
* Using the yield signal, the parent is able to inform the component
* about its wish to regain resources.
*/
virtual void yield_sigh(Signal_context_capability sigh) = 0;
/**
* Obtain information about the amount of resources to free
*
* The amount of resources returned by this method is the
* goal set by the parent. It is not commanded but merely meant
* as a friendly beg to cooperate. The component is not obligated
* to comply. If the component decides to take action to free
* resources, it can inform its parent about the availability
* of freed up resources by calling 'yield_response()'.
*/
virtual Resource_args yield_request() = 0;
/**
* Notify the parent about a response to a yield request
*/
virtual void yield_response() = 0;
/*********************
** RPC declaration **
*********************/
GENODE_RPC(Rpc_exit, void, exit, int);
GENODE_RPC(Rpc_announce, void, announce,
Service_name const &);
GENODE_RPC(Rpc_session_sigh, void, session_sigh, Signal_context_capability);
GENODE_RPC_THROW(Rpc_session, Session_capability, session,
GENODE_TYPE_LIST(Service_denied, Out_of_caps,
Out_of_ram, Insufficient_cap_quota,
Insufficient_ram_quota),
Client::Id, Service_name const &, Session_args const &,
Affinity const &);
GENODE_RPC_THROW(Rpc_session_cap, Session_capability, session_cap,
GENODE_TYPE_LIST(Service_denied, Insufficient_cap_quota,
Insufficient_ram_quota),
Client::Id);
GENODE_RPC_THROW(Rpc_upgrade, Upgrade_result, upgrade,
GENODE_TYPE_LIST(Out_of_ram, Out_of_caps),
Client::Id, Upgrade_args const &);
GENODE_RPC(Rpc_close, Close_result, close, Client::Id);
GENODE_RPC(Rpc_session_response, void, session_response,
Server::Id, Session_response);
GENODE_RPC(Rpc_deliver_session_cap, void, deliver_session_cap,
Server::Id, Session_capability);
GENODE_RPC(Rpc_main_thread, Thread_capability, main_thread_cap);
GENODE_RPC(Rpc_resource_avail_sigh, void, resource_avail_sigh,
Signal_context_capability);
GENODE_RPC(Rpc_resource_request, void, resource_request,
Resource_args const &);
GENODE_RPC(Rpc_yield_sigh, void, yield_sigh, Signal_context_capability);
GENODE_RPC(Rpc_yield_request, Resource_args, yield_request);
GENODE_RPC(Rpc_yield_response, void, yield_response);
GENODE_RPC_INTERFACE(Rpc_exit, Rpc_announce, Rpc_session_sigh,
Rpc_session, Rpc_session_cap, Rpc_upgrade,
Rpc_close, Rpc_session_response, Rpc_main_thread,
Rpc_deliver_session_cap, Rpc_resource_avail_sigh,
Rpc_resource_request, Rpc_yield_sigh,
Rpc_yield_request, Rpc_yield_response);
};
template <typename ROOT_INTERFACE>
void
Genode::Parent::_announce_base(Genode::Capability<ROOT_INTERFACE> const &service_root,
Genode::Meta::Bool_to_type<true> *)
{
/* shortcut for inherited session type */
typedef typename ROOT_INTERFACE::Session_type::Rpc_inherited_interface
Session_type_inherited;
/* shortcut for root interface type matching the inherited session type */
typedef Typed_root<Session_type_inherited> Root_inherited;
/* convert root capability to match the inherited session type */
Capability<Root> root = service_root;
Capability<Root_inherited> root_inherited = static_cap_cast<Root_inherited>(root);
/* announce inherited service type */
announce(Session_type_inherited::service_name(), root_inherited);
/* recursively announce further inherited session types */
_announce_base(root_inherited,
(Meta::Bool_to_type<Rpc_interface_is_inherited<Session_type_inherited>::VALUE> *)0);
}
#endif /* _INCLUDE__PARENT__PARENT_H_ */