1/*
2 * Copyright (C) 2013 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/*
18 * Read-only access to Zip archives, with minimal heap allocation.
19 */
20#ifndef LIBZIPARCHIVE_ZIPARCHIVE_H_
21#define LIBZIPARCHIVE_ZIPARCHIVE_H_
22
23#include <stdint.h>
24#include <string.h>
25#include <sys/cdefs.h>
26#include <sys/types.h>
27#include <utils/Compat.h>
28
29__BEGIN_DECLS
30
31/* Zip compression methods we support */
32enum {
33  kCompressStored     = 0,        // no compression
34  kCompressDeflated   = 8,        // standard deflate
35};
36
37struct ZipString {
38  const uint8_t* name;
39  uint16_t name_length;
40
41  ZipString() {}
42
43  /*
44   * entry_name has to be an c-style string with only ASCII characters.
45   */
46  explicit ZipString(const char* entry_name)
47      : name(reinterpret_cast<const uint8_t*>(entry_name)), name_length(strlen(entry_name)) {}
48
49  bool operator==(const ZipString& rhs) const {
50    return name && (name_length == rhs.name_length) &&
51        (memcmp(name, rhs.name, name_length) == 0);
52  }
53
54  bool StartsWith(const ZipString& prefix) const {
55    return name && (name_length >= prefix.name_length) &&
56        (memcmp(name, prefix.name, prefix.name_length) == 0);
57  }
58
59  bool EndsWith(const ZipString& suffix) const {
60    return name && (name_length >= suffix.name_length) &&
61        (memcmp(name + name_length - suffix.name_length, suffix.name,
62                suffix.name_length) == 0);
63  }
64};
65
66/*
67 * Represents information about a zip entry in a zip file.
68 */
69struct ZipEntry {
70  // Compression method: One of kCompressStored or
71  // kCompressDeflated.
72  uint16_t method;
73
74  // Modification time. The zipfile format specifies
75  // that the first two little endian bytes contain the time
76  // and the last two little endian bytes contain the date.
77  uint32_t mod_time;
78
79  // 1 if this entry contains a data descriptor segment, 0
80  // otherwise.
81  uint8_t has_data_descriptor;
82
83  // Crc32 value of this ZipEntry. This information might
84  // either be stored in the local file header or in a special
85  // Data descriptor footer at the end of the file entry.
86  uint32_t crc32;
87
88  // Compressed length of this ZipEntry. Might be present
89  // either in the local file header or in the data descriptor
90  // footer.
91  uint32_t compressed_length;
92
93  // Uncompressed length of this ZipEntry. Might be present
94  // either in the local file header or in the data descriptor
95  // footer.
96  uint32_t uncompressed_length;
97
98  // The offset to the start of data for this ZipEntry.
99  off64_t offset;
100};
101
102typedef void* ZipArchiveHandle;
103
104/*
105 * Open a Zip archive, and sets handle to the value of the opaque
106 * handle for the file. This handle must be released by calling
107 * CloseArchive with this handle.
108 *
109 * Returns 0 on success, and negative values on failure.
110 */
111int32_t OpenArchive(const char* fileName, ZipArchiveHandle* handle);
112
113/*
114 * Like OpenArchive, but takes a file descriptor open for reading
115 * at the start of the file.  The descriptor must be mappable (this does
116 * not allow access to a stream).
117 *
118 * Sets handle to the value of the opaque handle for this file descriptor.
119 * This handle must be released by calling CloseArchive with this handle.
120 *
121 * If assume_ownership parameter is 'true' calling CloseArchive will close
122 * the file.
123 *
124 * This function maps and scans the central directory and builds a table
125 * of entries for future lookups.
126 *
127 * "debugFileName" will appear in error messages, but is not otherwise used.
128 *
129 * Returns 0 on success, and negative values on failure.
130 */
131int32_t OpenArchiveFd(const int fd, const char* debugFileName,
132                      ZipArchiveHandle *handle, bool assume_ownership = true);
133
134/*
135 * Close archive, releasing resources associated with it. This will
136 * unmap the central directory of the zipfile and free all internal
137 * data structures associated with the file. It is an error to use
138 * this handle for any further operations without an intervening
139 * call to one of the OpenArchive variants.
140 */
141void CloseArchive(ZipArchiveHandle handle);
142
143/*
144 * Find an entry in the Zip archive, by name. |entryName| must be a null
145 * terminated string, and |data| must point to a writeable memory location.
146 *
147 * Returns 0 if an entry is found, and populates |data| with information
148 * about this entry. Returns negative values otherwise.
149 *
150 * It's important to note that |data->crc32|, |data->compLen| and
151 * |data->uncompLen| might be set to values from the central directory
152 * if this file entry contains a data descriptor footer. To verify crc32s
153 * and length, a call to VerifyCrcAndLengths must be made after entry data
154 * has been processed.
155 *
156 * On non-Windows platforms this method does not modify internal state and
157 * can be called concurrently.
158 */
159int32_t FindEntry(const ZipArchiveHandle handle, const ZipString& entryName,
160                  ZipEntry* data);
161
162/*
163 * Start iterating over all entries of a zip file. The order of iteration
164 * is not guaranteed to be the same as the order of elements
165 * in the central directory but is stable for a given zip file. |cookie| will
166 * contain the value of an opaque cookie which can be used to make one or more
167 * calls to Next. All calls to StartIteration must be matched by a call to
168 * EndIteration to free any allocated memory.
169 *
170 * This method also accepts optional prefix and suffix to restrict iteration to
171 * entry names that start with |optional_prefix| or end with |optional_suffix|.
172 *
173 * Returns 0 on success and negative values on failure.
174 */
175int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr,
176                       const ZipString* optional_prefix,
177                       const ZipString* optional_suffix);
178
179/*
180 * Advance to the next element in the zipfile in iteration order.
181 *
182 * Returns 0 on success, -1 if there are no more elements in this
183 * archive and lower negative values on failure.
184 */
185int32_t Next(void* cookie, ZipEntry* data, ZipString* name);
186
187/*
188 * End iteration over all entries of a zip file and frees the memory allocated
189 * in StartIteration.
190 */
191void EndIteration(void* cookie);
192
193/*
194 * Uncompress and write an entry to an open file identified by |fd|.
195 * |entry->uncompressed_length| bytes will be written to the file at
196 * its current offset, and the file will be truncated at the end of
197 * the uncompressed data.
198 *
199 * Returns 0 on success and negative values on failure.
200 */
201int32_t ExtractEntryToFile(ZipArchiveHandle handle, ZipEntry* entry, int fd);
202
203/**
204 * Uncompress a given zip entry to the memory region at |begin| and of
205 * size |size|. This size is expected to be the same as the *declared*
206 * uncompressed length of the zip entry. It is an error if the *actual*
207 * number of uncompressed bytes differs from this number.
208 *
209 * Returns 0 on success and negative values on failure.
210 */
211int32_t ExtractToMemory(ZipArchiveHandle handle, ZipEntry* entry,
212                        uint8_t* begin, uint32_t size);
213
214int GetFileDescriptor(const ZipArchiveHandle handle);
215
216const char* ErrorCodeString(int32_t error_code);
217
218__END_DECLS
219
220#endif  // LIBZIPARCHIVE_ZIPARCHIVE_H_
221