1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef LIBZIPARCHIVE_ZIPARCHIVECOMMON_H_
18#define LIBZIPARCHIVE_ZIPARCHIVECOMMON_H_
19
20#include "android-base/macros.h"
21
22#include <inttypes.h>
23
24// The "end of central directory" (EOCD) record. Each archive
25// contains exactly once such record which appears at the end of
26// the archive. It contains archive wide information like the
27// number of entries in the archive and the offset to the central
28// directory of the offset.
29struct EocdRecord {
30  static const uint32_t kSignature = 0x06054b50;
31
32  // End of central directory signature, should always be
33  // |kSignature|.
34  uint32_t eocd_signature;
35  // The number of the current "disk", i.e, the "disk" that this
36  // central directory is on.
37  //
38  // This implementation assumes that each archive spans a single
39  // disk only. i.e, that disk_num == 1.
40  uint16_t disk_num;
41  // The disk where the central directory starts.
42  //
43  // This implementation assumes that each archive spans a single
44  // disk only. i.e, that cd_start_disk == 1.
45  uint16_t cd_start_disk;
46  // The number of central directory records on this disk.
47  //
48  // This implementation assumes that each archive spans a single
49  // disk only. i.e, that num_records_on_disk == num_records.
50  uint16_t num_records_on_disk;
51  // The total number of central directory records.
52  uint16_t num_records;
53  // The size of the central directory (in bytes).
54  uint32_t cd_size;
55  // The offset of the start of the central directory, relative
56  // to the start of the file.
57  uint32_t cd_start_offset;
58  // Length of the central directory comment.
59  uint16_t comment_length;
60 private:
61  EocdRecord() = default;
62  DISALLOW_COPY_AND_ASSIGN(EocdRecord);
63} __attribute__((packed));
64
65// A structure representing the fixed length fields for a single
66// record in the central directory of the archive. In addition to
67// the fixed length fields listed here, each central directory
68// record contains a variable length "file_name" and "extra_field"
69// whose lengths are given by |file_name_length| and |extra_field_length|
70// respectively.
71struct CentralDirectoryRecord {
72  static const uint32_t kSignature = 0x02014b50;
73
74  // The start of record signature. Must be |kSignature|.
75  uint32_t record_signature;
76  // Tool version. Ignored by this implementation.
77  uint16_t version_made_by;
78  // Tool version. Ignored by this implementation.
79  uint16_t version_needed;
80  // The "general purpose bit flags" for this entry. The only
81  // flag value that we currently check for is the "data descriptor"
82  // flag.
83  uint16_t gpb_flags;
84  // The compression method for this entry, one of |kCompressStored|
85  // and |kCompressDeflated|.
86  uint16_t compression_method;
87  // The file modification time and date for this entry.
88  uint16_t last_mod_time;
89  uint16_t last_mod_date;
90  // The CRC-32 checksum for this entry.
91  uint32_t crc32;
92  // The compressed size (in bytes) of this entry.
93  uint32_t compressed_size;
94  // The uncompressed size (in bytes) of this entry.
95  uint32_t uncompressed_size;
96  // The length of the entry file name in bytes. The file name
97  // will appear immediately after this record.
98  uint16_t file_name_length;
99  // The length of the extra field info (in bytes). This data
100  // will appear immediately after the entry file name.
101  uint16_t extra_field_length;
102  // The length of the entry comment (in bytes). This data will
103  // appear immediately after the extra field.
104  uint16_t comment_length;
105  // The start disk for this entry. Ignored by this implementation).
106  uint16_t file_start_disk;
107  // File attributes. Ignored by this implementation.
108  uint16_t internal_file_attributes;
109  // File attributes. Ignored by this implementation.
110  uint32_t external_file_attributes;
111  // The offset to the local file header for this entry, from the
112  // beginning of this archive.
113  uint32_t local_file_header_offset;
114 private:
115  CentralDirectoryRecord() = default;
116  DISALLOW_COPY_AND_ASSIGN(CentralDirectoryRecord);
117} __attribute__((packed));
118
119// The local file header for a given entry. This duplicates information
120// present in the central directory of the archive. It is an error for
121// the information here to be different from the central directory
122// information for a given entry.
123struct LocalFileHeader {
124  static const uint32_t kSignature = 0x04034b50;
125
126  // The local file header signature, must be |kSignature|.
127  uint32_t lfh_signature;
128  // Tool version. Ignored by this implementation.
129  uint16_t version_needed;
130  // The "general purpose bit flags" for this entry. The only
131  // flag value that we currently check for is the "data descriptor"
132  // flag.
133  uint16_t gpb_flags;
134  // The compression method for this entry, one of |kCompressStored|
135  // and |kCompressDeflated|.
136  uint16_t compression_method;
137  // The file modification time and date for this entry.
138  uint16_t last_mod_time;
139  uint16_t last_mod_date;
140  // The CRC-32 checksum for this entry.
141  uint32_t crc32;
142  // The compressed size (in bytes) of this entry.
143  uint32_t compressed_size;
144  // The uncompressed size (in bytes) of this entry.
145  uint32_t uncompressed_size;
146  // The length of the entry file name in bytes. The file name
147  // will appear immediately after this record.
148  uint16_t file_name_length;
149  // The length of the extra field info (in bytes). This data
150  // will appear immediately after the entry file name.
151  uint16_t extra_field_length;
152 private:
153  LocalFileHeader() = default;
154  DISALLOW_COPY_AND_ASSIGN(LocalFileHeader);
155} __attribute__((packed));
156
157struct DataDescriptor {
158  // The *optional* data descriptor start signature.
159  static const uint32_t kOptSignature = 0x08074b50;
160
161  // CRC-32 checksum of the entry.
162  uint32_t crc32;
163  // Compressed size of the entry.
164  uint32_t compressed_size;
165  // Uncompressed size of the entry.
166  uint32_t uncompressed_size;
167 private:
168  DataDescriptor() = default;
169  DISALLOW_COPY_AND_ASSIGN(DataDescriptor);
170} __attribute__((packed));
171
172// mask value that signifies that the entry has a DD
173static const uint32_t kGPBDDFlagMask = 0x0008;
174
175// The maximum size of a central directory or a file
176// comment in bytes.
177static const uint32_t kMaxCommentLen = 65535;
178
179#endif /* LIBZIPARCHIVE_ZIPARCHIVECOMMON_H_ */
180