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