1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
/*
* Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Array.h>
#include <LibArchive/TarStream.h>
#include <string.h>
namespace Archive {
TarFileStream::TarFileStream(TarInputStream& tar_stream)
: m_tar_stream(tar_stream)
, m_generation(tar_stream.m_generation)
{
}
ErrorOr<Bytes> TarFileStream::read(Bytes bytes)
{
// Verify that the stream has not advanced.
VERIFY(m_tar_stream.m_generation == m_generation);
auto header_size = TRY(m_tar_stream.header().size());
auto to_read = min(bytes.size(), header_size - m_tar_stream.m_file_offset);
auto slice = TRY(m_tar_stream.m_stream->read(bytes.trim(to_read)));
m_tar_stream.m_file_offset += slice.size();
return slice;
}
bool TarFileStream::is_eof() const
{
// Verify that the stream has not advanced.
VERIFY(m_tar_stream.m_generation == m_generation);
auto header_size_or_error = m_tar_stream.header().size();
if (header_size_or_error.is_error())
return true;
auto header_size = header_size_or_error.release_value();
return m_tar_stream.m_stream->is_eof()
|| m_tar_stream.m_file_offset >= header_size;
}
ErrorOr<size_t> TarFileStream::write(ReadonlyBytes)
{
return Error::from_errno(EBADF);
}
ErrorOr<NonnullOwnPtr<TarInputStream>> TarInputStream::construct(NonnullOwnPtr<Core::Stream::Stream> stream)
{
auto tar_stream = TRY(adopt_nonnull_own_or_enomem(new (nothrow) TarInputStream(move(stream))));
TRY(tar_stream->load_next_header());
return tar_stream;
}
TarInputStream::TarInputStream(NonnullOwnPtr<Core::Stream::Stream> stream)
: m_stream(move(stream))
{
}
static constexpr unsigned long block_ceiling(unsigned long offset)
{
return block_size * (1 + ((offset - 1) / block_size));
}
ErrorOr<void> TarInputStream::advance()
{
if (finished())
return Error::from_string_literal("Attempted to advance a finished stream");
m_generation++;
// Discard the pending bytes of the current entry.
auto file_size = TRY(m_header.size());
TRY(m_stream->discard(block_ceiling(file_size) - m_file_offset));
m_file_offset = 0;
TRY(load_next_header());
return {};
}
ErrorOr<void> TarInputStream::load_next_header()
{
size_t number_of_consecutive_zero_blocks = 0;
while (true) {
auto header_span = TRY(m_stream->read(Bytes(&m_header, sizeof(m_header))));
if (header_span.size() != sizeof(m_header))
return Error::from_string_literal("Failed to read the entire header");
// Discard the rest of the header block.
TRY(m_stream->discard(block_size - sizeof(TarFileHeader)));
if (!header().is_zero_block())
break;
number_of_consecutive_zero_blocks++;
// Two zero blocks in a row marks the end of the archive.
if (number_of_consecutive_zero_blocks >= 2) {
m_found_end_of_archive = true;
return {};
}
}
if (!TRY(valid()))
return Error::from_string_literal("Header has an invalid magic or checksum");
return {};
}
ErrorOr<bool> TarInputStream::valid() const
{
auto const header_magic = header().magic();
auto const header_version = header().version();
if (!((header_magic == gnu_magic && header_version == gnu_version)
|| (header_magic == ustar_magic && header_version == ustar_version)
|| (header_magic == posix1_tar_magic && header_version == posix1_tar_version)))
return false;
// POSIX.1-1988 tar does not have magic numbers, so we also need to verify the header checksum.
return TRY(header().checksum()) == header().expected_checksum();
}
TarFileStream TarInputStream::file_contents()
{
VERIFY(!finished());
return TarFileStream(*this);
}
TarOutputStream::TarOutputStream(MaybeOwned<Core::Stream::Stream> stream)
: m_stream(move(stream))
{
}
ErrorOr<void> TarOutputStream::add_directory(StringView path, mode_t mode)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(0));
header.set_filename_and_prefix(TRY(String::formatted("{}/", path))); // Old tar implementations assume directory names end with a /
header.set_type_flag(TarFileType::Directory);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
TRY(header.calculate_checksum());
TRY(m_stream->write_entire_buffer(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
TRY(m_stream->write_entire_buffer(Bytes { &padding, block_size - sizeof(header) }));
return {};
}
ErrorOr<void> TarOutputStream::add_file(StringView path, mode_t mode, ReadonlyBytes bytes)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(bytes.size()));
header.set_filename_and_prefix(path);
header.set_type_flag(TarFileType::NormalFile);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
TRY(header.calculate_checksum());
TRY(m_stream->write_entire_buffer(ReadonlyBytes { &header, sizeof(header) }));
constexpr Array<u8, block_size> padding { 0 };
TRY(m_stream->write_entire_buffer(ReadonlyBytes { &padding, block_size - sizeof(header) }));
size_t n_written = 0;
while (n_written < bytes.size()) {
n_written += MUST(m_stream->write(bytes.slice(n_written, min(bytes.size() - n_written, block_size))));
}
TRY(m_stream->write_entire_buffer(ReadonlyBytes { &padding, block_size - (n_written % block_size) }));
return {};
}
ErrorOr<void> TarOutputStream::add_link(StringView path, mode_t mode, StringView link_name)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(0));
header.set_filename_and_prefix(path);
header.set_type_flag(TarFileType::SymLink);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.set_link_name(link_name);
TRY(header.calculate_checksum());
TRY(m_stream->write_entire_buffer(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
TRY(m_stream->write_entire_buffer(Bytes { &padding, block_size - sizeof(header) }));
return {};
}
ErrorOr<void> TarOutputStream::finish()
{
VERIFY(!m_finished);
constexpr Array<u8, block_size> padding { 0 };
// 2 empty records that are used to signify the end of the archive.
TRY(m_stream->write_entire_buffer(ReadonlyBytes { &padding, block_size }));
TRY(m_stream->write_entire_buffer(ReadonlyBytes { &padding, block_size }));
m_finished = true;
return {};
}
}
|
