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	 21d5f4ada1
			
		
	
	
		21d5f4ada1
		
	
	
	
	
		
			
			This was supposed to be the foundation for some kind of pre-kernel environment, but nobody is working on it right now, so let's move everything back into the kernel and remove all the confusion.
		
			
				
	
	
		
			105 lines
		
	
	
	
		
			4.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			105 lines
		
	
	
	
		
			4.2 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/NonnullRefPtr.h>
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| #include <AK/RefCounted.h>
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| #include <AK/String.h>
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| #include <AK/Types.h>
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| #include <Kernel/Forward.h>
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| #include <Kernel/KResult.h>
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| #include <Kernel/UnixTypes.h>
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| #include <Kernel/VirtualAddress.h>
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| 
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| namespace Kernel {
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| 
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| // File is the base class for anything that can be referenced by a FileDescription.
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| //
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| // The most important functions in File are:
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| //
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| // read() and write()
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| //   - Implement reading and writing.
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| //   - Return the number of bytes read/written, OR a negative error code.
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| //
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| // can_read() and can_write()
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| //
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| //   - Used to implement blocking I/O, and the select() and poll() syscalls.
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| //   - Return true if read() or write() would succeed, respectively.
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| //   - Note that can_read() should return true in EOF conditions,
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| //     and a subsequent call to read() should return 0.
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| //
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| // ioctl()
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| //
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| //   - Optional. If unimplemented, ioctl() on this File will fail with -ENOTTY.
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| //   - Can be overridden in subclasses to implement arbitrary functionality.
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| //   - Subclasses should take care to validate incoming addresses before dereferencing.
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| //
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| // mmap()
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| //
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| //   - Optional. If unimplemented, mmap() on this File will fail with -ENODEV.
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| //   - Called by mmap() when userspace wants to memory-map this File somewhere.
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| //   - Should create a Region in the Process and return it if successful.
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| 
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| class File : public RefCounted<File> {
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| public:
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|     virtual ~File();
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| 
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|     virtual KResultOr<NonnullRefPtr<FileDescription>> open(int options);
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|     virtual void close();
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| 
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|     virtual bool can_read(const FileDescription&, size_t) const = 0;
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|     virtual bool can_write(const FileDescription&, size_t) const = 0;
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| 
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|     virtual ssize_t read(FileDescription&, size_t, u8*, ssize_t) = 0;
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|     virtual ssize_t write(FileDescription&, size_t, const u8*, ssize_t) = 0;
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|     virtual int ioctl(FileDescription&, unsigned request, unsigned arg);
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|     virtual KResultOr<Region*> mmap(Process&, FileDescription&, VirtualAddress preferred_vaddr, size_t offset, size_t size, int prot, bool shared);
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| 
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|     virtual String absolute_path(const FileDescription&) const = 0;
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| 
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|     virtual KResult truncate(u64) { return KResult(-EINVAL); }
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|     virtual KResult chown(uid_t, gid_t) { return KResult(-EBADF); }
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|     virtual KResult chmod(mode_t) { return KResult(-EBADF); }
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| 
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|     virtual const char* class_name() const = 0;
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| 
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|     virtual bool is_seekable() const { return false; }
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| 
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|     virtual bool is_inode() const { return false; }
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|     virtual bool is_fifo() const { return false; }
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|     virtual bool is_device() const { return false; }
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|     virtual bool is_tty() const { return false; }
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|     virtual bool is_master_pty() const { return false; }
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|     virtual bool is_block_device() const { return false; }
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|     virtual bool is_character_device() const { return false; }
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|     virtual bool is_socket() const { return false; }
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| 
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| protected:
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|     File();
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| };
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| 
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| }
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