genode/repos/base-linux/src/lib/base/platform_env.cc

/*
 * \brief  Support for the Linux-specific environment
 * \author Norman Feske
 * \date   2008-12-12
 */

/*
 * Copyright (C) 2008-2017 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.
 */

/* Genode includes */
#include <util/arg_string.h>
#include <base/thread.h>
#include <linux_dataspace/client.h>
#include <linux_syscalls.h>

/* base-internal includes */
#include <base/internal/platform_env.h>
#include <base/internal/native_thread.h>
#include <base/internal/globals.h>
#include <base/internal/parent_socket_handle.h>
#include <base/internal/capability_space_tpl.h>

using namespace Genode;


/****************************************************
 ** Support for Platform_env_base::Rm_session_mmap **
 ****************************************************/

size_t Region_map_mmap::_dataspace_size(Dataspace_capability ds)
{
	if (local(ds))
		return Local_capability<Dataspace>::deref(ds)->size();

	return Dataspace_client(ds).size();

}


int Region_map_mmap::_dataspace_fd(Dataspace_capability ds)
{
	Untyped_capability fd_cap = Linux_dataspace_client(ds).fd();
	return Capability_space::ipc_cap_data(fd_cap).dst.socket;
}


bool Region_map_mmap::_dataspace_writable(Dataspace_capability ds)
{
	return Dataspace_client(ds).writable();
}



/******************
 ** Local_parent **
 ******************/

Session_capability Local_parent::session(Parent::Client::Id  id,
                                         Service_name const &service_name,
                                         Session_args const &args,
                                         Affinity     const &affinity)
{
	if (strcmp(service_name.string(), Rm_session::service_name()) == 0) {

		Local_rm_session *local_rm_session = new (_alloc)
			Local_rm_session(_alloc, _local_sessions_id_space, id);

		return local_rm_session->local_session_cap();
	}

	return Expanding_parent_client::session(id, service_name, args, affinity);
}


Parent::Close_result Local_parent::close(Client::Id id)
{
	auto close_local_fn = [&] (Local_session &local_session)
	{
		Capability<Rm_session> rm =
			static_cap_cast<Rm_session>(local_session.local_session_cap());
		destroy(_alloc, Local_capability<Rm_session>::deref(rm));
	};

	/*
	 * Local RM sessions are present in the '_local_sessions_id_space'. If the
	 * apply succeeds, 'id' referred to the local session. Otherwise, we
	 * forward the request to the parent.
	 */
	try {
		_local_sessions_id_space.apply<Local_session>(id, close_local_fn);
		return CLOSE_DONE;
	}
	catch (Id_space<Client>::Unknown_id) { }

	return Parent_client::close(id);
}


Local_parent::Local_parent(Parent_capability parent_cap,
                           Emergency_ram_reserve &reserve,
                           Allocator &alloc)
:
	Expanding_parent_client(parent_cap, reserve), _alloc(alloc)
{ }


/******************
 ** Platform_env **
 ******************/

/**
 * List of Unix environment variables, initialized by the startup code
 */
extern char **lx_environ;


/**
 * Read environment variable as long value
 */
static unsigned long get_env_ulong(const char *key)
{
	for (char **curr = lx_environ; curr && *curr; curr++) {

		Arg arg = Arg_string::find_arg(*curr, key);
		if (arg.valid())
			return arg.ulong_value(0);
	}

	return 0;
}


static Parent_capability obtain_parent_cap()
{
	long const local_name = get_env_ulong("parent_local_name");

	Untyped_capability parent_cap =
		Capability_space::import(Rpc_destination(PARENT_SOCKET_HANDLE),
		                         Rpc_obj_key(local_name));

	return reinterpret_cap_cast<Parent>(parent_cap);
}


Local_parent &Platform_env::_parent()
{
	static Local_parent local_parent(obtain_parent_cap(), *this, _heap);
	return local_parent;
}


Platform_env::Platform_env()
:
	Platform_env_base(static_cap_cast<Ram_session>(_parent().session_cap(Parent::Env::ram())),
	                  static_cap_cast<Cpu_session>(_parent().session_cap(Parent::Env::cpu())),
	                  static_cap_cast<Pd_session> (_parent().session_cap(Parent::Env::pd()))),
	_heap(Platform_env_base::ram_session(), Platform_env_base::rm_session()),
	_emergency_ram_ds(ram_session()->alloc(_emergency_ram_size()))
{
	_attach_stack_area();

	env_stack_area_region_map    = &_local_pd_session._stack_area;
	env_stack_area_ram_allocator = ram_session();

	/* register TID and PID of the main thread at core */
	Linux_native_cpu_client native_cpu(cpu_session()->native_cpu());
	native_cpu.thread_id(parent()->main_thread_cap(), lx_getpid(), lx_gettid());
}


/*****************************
 ** Support for IPC library **
 *****************************/

namespace Genode {

	Socket_pair server_socket_pair()
	{
		Linux_native_cpu_client native_cpu(env_deprecated()->cpu_session()->native_cpu());

		Socket_pair socket_pair;

		Thread *thread = Thread::myself();
		if (thread) {
			Untyped_capability server_cap = native_cpu.server_sd(thread->cap());
			Untyped_capability client_cap = native_cpu.client_sd(thread->cap());
			socket_pair.server_sd = Capability_space::ipc_cap_data(server_cap).dst.socket;
			socket_pair.client_sd = Capability_space::ipc_cap_data(client_cap).dst.socket;
			thread->native_thread().socket_pair = socket_pair;
		}
		return socket_pair;
	}

	void destroy_server_socket_pair(Socket_pair socket_pair)
	{
		/* close local file descriptor if it is valid */
		if (socket_pair.server_sd != -1) lx_close(socket_pair.server_sd);
		if (socket_pair.client_sd != -1) lx_close(socket_pair.client_sd);
	}
}