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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/OwnPtr.h>
#include <AK/WeakPtr.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/PurgeableVMObject.h>
namespace Kernel {
class SharedBuffer {
private:
struct Reference {
Reference(pid_t pid)
: pid(pid)
{
}
pid_t pid;
unsigned count { 0 };
WeakPtr<Region> region;
};
public:
SharedBuffer(int id, int size)
: m_shbuf_id(id)
, m_vmobject(PurgeableVMObject::create_with_size(size))
{
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Created shared buffer " << m_shbuf_id << " of size " << size;
#endif
}
~SharedBuffer()
{
#ifdef SHARED_BUFFER_DEBUG
dbg() << "Destroyed shared buffer " << m_shbuf_id << " of size " << size();
#endif
}
void sanity_check(const char* what);
bool is_shared_with(pid_t peer_pid) const;
void* ref_for_process_and_get_address(Process& process);
void share_with(pid_t peer_pid);
void share_globally() { m_global = true; }
void deref_for_process(Process& process);
void disown(pid_t pid);
size_t size() const { return m_vmobject->size(); }
void destroy_if_unused();
void seal();
PurgeableVMObject& vmobject() { return m_vmobject; }
const PurgeableVMObject& vmobject() const { return m_vmobject; }
int id() const { return m_shbuf_id; }
private:
int m_shbuf_id { -1 };
bool m_writable { true };
bool m_global { false };
NonnullRefPtr<PurgeableVMObject> m_vmobject;
Vector<Reference, 2> m_refs;
unsigned m_total_refs { 0 };
};
Lockable<HashMap<int, NonnullOwnPtr<SharedBuffer>>>& shared_buffers();
}
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