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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#include <AK/String.h>
28#include <AK/MappedFile.h>
29#include <fcntl.h>
30#include <stdio.h>
31#include <sys/mman.h>
32#include <sys/stat.h>
33#include <unistd.h>
34
35//#define DEBUG_MAPPED_FILE
36
37namespace AK {
38
39MappedFile::MappedFile(const StringView& file_name)
40{
41 m_size = PAGE_SIZE;
42 int fd = open_with_path_length(file_name.characters_without_null_termination(), file_name.length(), O_RDONLY | O_CLOEXEC, 0);
43
44 if (fd == -1) {
45 perror("open");
46 return;
47 }
48
49 struct stat st;
50 fstat(fd, &st);
51 m_size = st.st_size;
52 m_map = mmap(nullptr, m_size, PROT_READ, MAP_SHARED, fd, 0);
53
54 if (m_map == MAP_FAILED)
55 perror("mmap");
56
57#ifdef DEBUG_MAPPED_FILE
58 dbgprintf("MappedFile{%s} := { fd=%d, m_size=%u, m_map=%p }\n", file_name.characters(), fd, m_size, m_map);
59#endif
60
61 close(fd);
62}
63
64MappedFile::~MappedFile()
65{
66 unmap();
67}
68
69void MappedFile::unmap()
70{
71 if (!is_valid())
72 return;
73 int rc = munmap(m_map, m_size);
74 ASSERT(rc == 0);
75 m_size = 0;
76 m_map = (void*)-1;
77}
78
79MappedFile::MappedFile(MappedFile&& other)
80 : m_size(other.m_size)
81 , m_map(other.m_map)
82{
83 other.m_size = 0;
84 other.m_map = (void*)-1;
85}
86
87MappedFile& MappedFile::operator=(MappedFile&& other)
88{
89 if (this == &other)
90 return *this;
91 unmap();
92 swap(m_size, other.m_size);
93 swap(m_map, other.m_map);
94 return *this;
95}
96
97}