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ca004658d9
Implements Native_capability as smart-pointer type referencing Cap_index objects. Whenever capabilities are copied, assigned, constructed, or destructed the reference-counter of the Cap_index is incremented/decremented. When it reaches zero the Cap_index is removed from the process-global cap_map and gets freed. Fix for issue #32.
94 lines
2.4 KiB
C++
94 lines
2.4 KiB
C++
/*
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* \brief Fiasco.OC-specific supplements to the IPC framework
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* \author Norman Feske
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* \author Stefan Kalkowski
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* \date 2010-01-27
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*/
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/*
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* Copyright (C) 2010-2012 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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#ifndef _INCLUDE__BASE__IPC_H_
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#define _INCLUDE__BASE__IPC_H_
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#include <base/ipc_generic.h>
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namespace Fiasco {
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#include <l4/sys/consts.h>
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#include <l4/sys/task.h>
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}
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inline void Genode::Ipc_ostream::_marshal_capability(Genode::Native_capability const &cap)
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{
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bool local = cap.local();
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long id = local ? (long)cap.local() : cap.local_name();
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_write_to_buf(local);
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_write_to_buf(id);
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/* only transfer kernel-capability if it's no local capability and valid */
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if (!local && id)
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_snd_msg->snd_append_cap_sel(cap.dst());
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}
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inline void Genode::Ipc_istream::_unmarshal_capability(Genode::Native_capability &cap)
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{
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using namespace Fiasco;
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bool local = false;
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long id = 0;
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/* extract capability id from message buffer, and whether it's a local cap */
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_read_from_buf(local);
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_read_from_buf(id);
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/* if it's a local capability, the pointer is marshalled in the id */
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if (local) {
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cap = Capability<Native_capability>::local_cap((Native_capability*)id);
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return;
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}
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/* if id is zero an invalid capability was transfered */
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if (!id) {
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cap = Native_capability();
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return;
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}
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/* we received a valid, non-local capability, maybe we already own it? */
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Cap_index *i = cap_map()->find(id);
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Genode::addr_t rcv_cap = _rcv_msg->rcv_cap_sel();
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if (i) {
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/**
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* If we've a dead capability in our database, which is already
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* revoked, its id might be reused.
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*/
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l4_msgtag_t tag = l4_task_cap_valid(L4_BASE_TASK_CAP, i->kcap());
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if (!l4_msgtag_label(tag)) {
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i->inc();
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PWRN("leaking capability idx=%p id=%x ref_cnt=%d",i, i->id(), i->dec());
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} else {
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/* does somebody tries to fake us? */
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tag = l4_task_cap_equal(L4_BASE_TASK_CAP, i->kcap(), rcv_cap);
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if (!l4_msgtag_label(tag)) {
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PWRN("Got fake capability");
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cap = Native_capability();
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} else
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cap = Native_capability(i);
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return;
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}
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}
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/* insert the new capability in the map */
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i = cap_map()->insert(id);
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l4_task_map(L4_BASE_TASK_CAP, L4_BASE_TASK_CAP,
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l4_obj_fpage(rcv_cap, 0, L4_FPAGE_RWX),
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i->kcap() | L4_ITEM_MAP | L4_MAP_ITEM_GRANT);
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cap = Native_capability(i);
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}
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#endif /* _INCLUDE__BASE__IPC_H_ */
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