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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <Kernel/DoubleBuffer.h>
30#include <Kernel/FileSystem/File.h>
31#include <Kernel/UnixTypes.h>
32
33namespace Kernel {
34
35class FileDescription;
36
37class FIFO final : public File {
38public:
39 enum class Direction : u8 {
40 Neither,
41 Reader,
42 Writer
43 };
44
45 static NonnullRefPtr<FIFO> create(uid_t);
46 virtual ~FIFO() override;
47
48 uid_t uid() const { return m_uid; }
49
50 NonnullRefPtr<FileDescription> open_direction(Direction);
51
52 void attach(Direction);
53 void detach(Direction);
54
55private:
56 // ^File
57 virtual ssize_t write(FileDescription&, const u8*, ssize_t) override;
58 virtual ssize_t read(FileDescription&, u8*, ssize_t) override;
59 virtual bool can_read(const FileDescription&) const override;
60 virtual bool can_write(const FileDescription&) const override;
61 virtual String absolute_path(const FileDescription&) const override;
62 virtual const char* class_name() const override { return "FIFO"; }
63 virtual bool is_fifo() const override { return true; }
64
65 explicit FIFO(uid_t);
66
67 unsigned m_writers { 0 };
68 unsigned m_readers { 0 };
69 DoubleBuffer m_buffer;
70
71 uid_t m_uid { 0 };
72
73 int m_fifo_id { 0 };
74};
75
76}