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 /* Zip compression methods we support */ 30 enum { 31 kCompressStored = 0, // no compression 32 kCompressDeflated = 8, // standard deflate 33 }; 34 35 struct ZipString { 36 const uint8_t* name; 37 uint16_t name_length; 38 ZipStringZipString39 ZipString() {} 40 41 /* 42 * entry_name has to be an c-style string with only ASCII characters. 43 */ 44 explicit ZipString(const char* entry_name); 45 46 bool operator==(const ZipString& rhs) const { 47 return name && (name_length == rhs.name_length) && 48 (memcmp(name, rhs.name, name_length) == 0); 49 } 50 StartsWithZipString51 bool StartsWith(const ZipString& prefix) const { 52 return name && (name_length >= prefix.name_length) && 53 (memcmp(name, prefix.name, prefix.name_length) == 0); 54 } 55 EndsWithZipString56 bool EndsWith(const ZipString& suffix) const { 57 return name && (name_length >= suffix.name_length) && 58 (memcmp(name + name_length - suffix.name_length, suffix.name, 59 suffix.name_length) == 0); 60 } 61 }; 62 63 /* 64 * Represents information about a zip entry in a zip file. 65 */ 66 struct ZipEntry { 67 // Compression method: One of kCompressStored or 68 // kCompressDeflated. 69 uint16_t method; 70 71 // Modification time. The zipfile format specifies 72 // that the first two little endian bytes contain the time 73 // and the last two little endian bytes contain the date. 74 uint32_t mod_time; 75 76 // 1 if this entry contains a data descriptor segment, 0 77 // otherwise. 78 uint8_t has_data_descriptor; 79 80 // Crc32 value of this ZipEntry. This information might 81 // either be stored in the local file header or in a special 82 // Data descriptor footer at the end of the file entry. 83 uint32_t crc32; 84 85 // Compressed length of this ZipEntry. Might be present 86 // either in the local file header or in the data descriptor 87 // footer. 88 uint32_t compressed_length; 89 90 // Uncompressed length of this ZipEntry. Might be present 91 // either in the local file header or in the data descriptor 92 // footer. 93 uint32_t uncompressed_length; 94 95 // The offset to the start of data for this ZipEntry. 96 off64_t offset; 97 }; 98 99 typedef void* ZipArchiveHandle; 100 101 /* 102 * Open a Zip archive, and sets handle to the value of the opaque 103 * handle for the file. This handle must be released by calling 104 * CloseArchive with this handle. 105 * 106 * Returns 0 on success, and negative values on failure. 107 */ 108 int32_t OpenArchive(const char* fileName, ZipArchiveHandle* handle); 109 110 /* 111 * Like OpenArchive, but takes a file descriptor open for reading 112 * at the start of the file. The descriptor must be mappable (this does 113 * not allow access to a stream). 114 * 115 * Sets handle to the value of the opaque handle for this file descriptor. 116 * This handle must be released by calling CloseArchive with this handle. 117 * 118 * If assume_ownership parameter is 'true' calling CloseArchive will close 119 * the file. 120 * 121 * This function maps and scans the central directory and builds a table 122 * of entries for future lookups. 123 * 124 * "debugFileName" will appear in error messages, but is not otherwise used. 125 * 126 * Returns 0 on success, and negative values on failure. 127 */ 128 int32_t OpenArchiveFd(const int fd, const char* debugFileName, 129 ZipArchiveHandle *handle, bool assume_ownership = true); 130 131 int32_t OpenArchiveFromMemory(void* address, size_t length, const char* debugFileName, 132 ZipArchiveHandle *handle); 133 /* 134 * Close archive, releasing resources associated with it. This will 135 * unmap the central directory of the zipfile and free all internal 136 * data structures associated with the file. It is an error to use 137 * this handle for any further operations without an intervening 138 * call to one of the OpenArchive variants. 139 */ 140 void CloseArchive(ZipArchiveHandle handle); 141 142 /* 143 * Find an entry in the Zip archive, by name. |entryName| must be a null 144 * terminated string, and |data| must point to a writeable memory location. 145 * 146 * Returns 0 if an entry is found, and populates |data| with information 147 * about this entry. Returns negative values otherwise. 148 * 149 * It's important to note that |data->crc32|, |data->compLen| and 150 * |data->uncompLen| might be set to values from the central directory 151 * if this file entry contains a data descriptor footer. To verify crc32s 152 * and length, a call to VerifyCrcAndLengths must be made after entry data 153 * has been processed. 154 * 155 * On non-Windows platforms this method does not modify internal state and 156 * can be called concurrently. 157 */ 158 int32_t FindEntry(const ZipArchiveHandle handle, const ZipString& entryName, 159 ZipEntry* data); 160 161 /* 162 * Start iterating over all entries of a zip file. The order of iteration 163 * is not guaranteed to be the same as the order of elements 164 * in the central directory but is stable for a given zip file. |cookie| will 165 * contain the value of an opaque cookie which can be used to make one or more 166 * calls to Next. All calls to StartIteration must be matched by a call to 167 * EndIteration to free any allocated memory. 168 * 169 * This method also accepts optional prefix and suffix to restrict iteration to 170 * entry names that start with |optional_prefix| or end with |optional_suffix|. 171 * 172 * Returns 0 on success and negative values on failure. 173 */ 174 int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr, 175 const ZipString* optional_prefix, 176 const ZipString* optional_suffix); 177 178 /* 179 * Advance to the next element in the zipfile in iteration order. 180 * 181 * Returns 0 on success, -1 if there are no more elements in this 182 * archive and lower negative values on failure. 183 */ 184 int32_t Next(void* cookie, ZipEntry* data, ZipString* name); 185 186 /* 187 * End iteration over all entries of a zip file and frees the memory allocated 188 * in StartIteration. 189 */ 190 void EndIteration(void* cookie); 191 192 /* 193 * Uncompress and write an entry to an open file identified by |fd|. 194 * |entry->uncompressed_length| bytes will be written to the file at 195 * its current offset, and the file will be truncated at the end of 196 * the uncompressed data (no truncation if |fd| references a block 197 * device). 198 * 199 * Returns 0 on success and negative values on failure. 200 */ 201 int32_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 */ 211 int32_t ExtractToMemory(ZipArchiveHandle handle, ZipEntry* entry, 212 uint8_t* begin, uint32_t size); 213 214 int GetFileDescriptor(const ZipArchiveHandle handle); 215 216 const char* ErrorCodeString(int32_t error_code); 217 218 #if !defined(_WIN32) 219 typedef bool (*ProcessZipEntryFunction)(const uint8_t* buf, size_t buf_size, void* cookie); 220 221 /* 222 * Stream the uncompressed data through the supplied function, 223 * passing cookie to it each time it gets called. 224 */ 225 int32_t ProcessZipEntryContents(ZipArchiveHandle handle, ZipEntry* entry, 226 ProcessZipEntryFunction func, void* cookie); 227 #endif 228 229 #endif // LIBZIPARCHIVE_ZIPARCHIVE_H_ 230