96 lines
2.1 KiB
C++
96 lines
2.1 KiB
C++
/*
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* \brief A guard for RAM session clients to limit memory exhaustion
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* \author Christian Prochaska
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* \date 2012-04-25
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*/
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/*
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* Copyright (C) 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 _RAM_SESSION_CLIENT_GUARD_H_
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#define _RAM_SESSION_CLIENT_GUARD_H_
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#include <base/lock.h>
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#include <base/printf.h>
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#include <dataspace/client.h>
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#include <ram_session/client.h>
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namespace Genode {
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class Ram_session_client_guard : public Ram_session_client
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{
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private:
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size_t _amount; /* total amount */
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size_t _consumed; /* already consumed bytes */
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Lock _consumed_lock;
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public:
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Ram_session_client_guard(Ram_session_capability session, size_t amount)
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: Ram_session_client(session), _amount(amount), _consumed(0) { }
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Ram_dataspace_capability alloc(size_t size, bool cached)
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{
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Lock::Guard _consumed_lock_guard(_consumed_lock);
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if ((_amount - _consumed) < size) {
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PWRN("Quota exceeded! amount=%zu, size=%zu, consumed=%zu",
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_amount, size, _consumed);
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return Ram_dataspace_capability();
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}
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Ram_dataspace_capability cap =
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Ram_session_client::alloc(size, cached);
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_consumed += size;
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return cap;
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}
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void free(Ram_dataspace_capability ds)
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{
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Lock::Guard _consumed_lock_guard(_consumed_lock);
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_consumed -= Dataspace_client(ds).size();
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Ram_session_client::free(ds);
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}
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int transfer_quota(Ram_session_capability ram_session, size_t amount)
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{
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Lock::Guard _consumed_lock_guard(_consumed_lock);
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if ((_amount - _consumed) < amount) {
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PWRN("Quota exceeded! amount=%zu, size=%zu, consumed=%zu",
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_amount, amount, _consumed);
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return -1;
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}
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int result = Ram_session_client::transfer_quota(ram_session, amount);
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if (result == 0)
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_consumed += amount;
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return result;
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}
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size_t quota()
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{
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return _amount;
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}
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size_t used()
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{
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Lock::Guard _consumed_lock_guard(_consumed_lock);
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return _consumed;
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}
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};
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}
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#endif /* _RAM_SESSION_CLIENT_GUARD_H_ */
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