zip_archive.h revision cdf7ff8e204beb6bbfe263c3d6255c2b2d0095a7
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 */ 30enum { 31 kCompressStored = 0, // no compression 32 kCompressDeflated = 8, // standard deflate 33}; 34 35struct ZipString { 36 const uint8_t* name; 37 uint16_t name_length; 38 39 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) && (memcmp(name, rhs.name, name_length) == 0); 48 } 49 50 bool StartsWith(const ZipString& prefix) const { 51 return name && (name_length >= prefix.name_length) && 52 (memcmp(name, prefix.name, prefix.name_length) == 0); 53 } 54 55 bool EndsWith(const ZipString& suffix) const { 56 return name && (name_length >= suffix.name_length) && 57 (memcmp(name + name_length - suffix.name_length, suffix.name, suffix.name_length) == 0); 58 } 59}; 60 61/* 62 * Represents information about a zip entry in a zip file. 63 */ 64struct ZipEntry { 65 // Compression method: One of kCompressStored or 66 // kCompressDeflated. 67 uint16_t method; 68 69 // Modification time. The zipfile format specifies 70 // that the first two little endian bytes contain the time 71 // and the last two little endian bytes contain the date. 72 // See `GetModificationTime`. 73 // TODO: should be overridden by extra time field, if present. 74 uint32_t mod_time; 75 76 // Returns `mod_time` as a broken-down struct tm. 77 struct tm GetModificationTime() const; 78 79 // Suggested Unix mode for this entry, from the zip archive if created on 80 // Unix, or a default otherwise. 81 mode_t unix_mode; 82 83 // 1 if this entry contains a data descriptor segment, 0 84 // otherwise. 85 uint8_t has_data_descriptor; 86 87 // Crc32 value of this ZipEntry. This information might 88 // either be stored in the local file header or in a special 89 // Data descriptor footer at the end of the file entry. 90 uint32_t crc32; 91 92 // Compressed length of this ZipEntry. Might be present 93 // either in the local file header or in the data descriptor 94 // footer. 95 uint32_t compressed_length; 96 97 // Uncompressed length of this ZipEntry. Might be present 98 // either in the local file header or in the data descriptor 99 // footer. 100 uint32_t uncompressed_length; 101 102 // The offset to the start of data for this ZipEntry. 103 off64_t offset; 104}; 105 106typedef void* ZipArchiveHandle; 107 108/* 109 * Open a Zip archive, and sets handle to the value of the opaque 110 * handle for the file. This handle must be released by calling 111 * CloseArchive with this handle. 112 * 113 * Returns 0 on success, and negative values on failure. 114 */ 115int32_t OpenArchive(const char* fileName, ZipArchiveHandle* handle); 116 117/* 118 * Like OpenArchive, but takes a file descriptor open for reading 119 * at the start of the file. The descriptor must be mappable (this does 120 * not allow access to a stream). 121 * 122 * Sets handle to the value of the opaque handle for this file descriptor. 123 * This handle must be released by calling CloseArchive with this handle. 124 * 125 * If assume_ownership parameter is 'true' calling CloseArchive will close 126 * the file. 127 * 128 * This function maps and scans the central directory and builds a table 129 * of entries for future lookups. 130 * 131 * "debugFileName" will appear in error messages, but is not otherwise used. 132 * 133 * Returns 0 on success, and negative values on failure. 134 */ 135int32_t OpenArchiveFd(const int fd, const char* debugFileName, ZipArchiveHandle* handle, 136 bool assume_ownership = true); 137 138int32_t OpenArchiveFromMemory(void* address, size_t length, const char* debugFileName, 139 ZipArchiveHandle* handle); 140/* 141 * Close archive, releasing resources associated with it. This will 142 * unmap the central directory of the zipfile and free all internal 143 * data structures associated with the file. It is an error to use 144 * this handle for any further operations without an intervening 145 * call to one of the OpenArchive variants. 146 */ 147void CloseArchive(ZipArchiveHandle handle); 148 149/* 150 * Find an entry in the Zip archive, by name. |entryName| must be a null 151 * terminated string, and |data| must point to a writeable memory location. 152 * 153 * Returns 0 if an entry is found, and populates |data| with information 154 * about this entry. Returns negative values otherwise. 155 * 156 * It's important to note that |data->crc32|, |data->compLen| and 157 * |data->uncompLen| might be set to values from the central directory 158 * if this file entry contains a data descriptor footer. To verify crc32s 159 * and length, a call to VerifyCrcAndLengths must be made after entry data 160 * has been processed. 161 * 162 * On non-Windows platforms this method does not modify internal state and 163 * can be called concurrently. 164 */ 165int32_t FindEntry(const ZipArchiveHandle handle, const ZipString& entryName, ZipEntry* data); 166 167/* 168 * Start iterating over all entries of a zip file. The order of iteration 169 * is not guaranteed to be the same as the order of elements 170 * in the central directory but is stable for a given zip file. |cookie| will 171 * contain the value of an opaque cookie which can be used to make one or more 172 * calls to Next. All calls to StartIteration must be matched by a call to 173 * EndIteration to free any allocated memory. 174 * 175 * This method also accepts optional prefix and suffix to restrict iteration to 176 * entry names that start with |optional_prefix| or end with |optional_suffix|. 177 * 178 * Returns 0 on success and negative values on failure. 179 */ 180int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr, const ZipString* optional_prefix, 181 const ZipString* optional_suffix); 182 183/* 184 * Advance to the next element in the zipfile in iteration order. 185 * 186 * Returns 0 on success, -1 if there are no more elements in this 187 * archive and lower negative values on failure. 188 */ 189int32_t Next(void* cookie, ZipEntry* data, ZipString* name); 190 191/* 192 * End iteration over all entries of a zip file and frees the memory allocated 193 * in StartIteration. 194 */ 195void EndIteration(void* cookie); 196 197/* 198 * Uncompress and write an entry to an open file identified by |fd|. 199 * |entry->uncompressed_length| bytes will be written to the file at 200 * its current offset, and the file will be truncated at the end of 201 * the uncompressed data (no truncation if |fd| references a block 202 * device). 203 * 204 * Returns 0 on success and negative values on failure. 205 */ 206int32_t ExtractEntryToFile(ZipArchiveHandle handle, ZipEntry* entry, int fd); 207 208/** 209 * Uncompress a given zip entry to the memory region at |begin| and of 210 * size |size|. This size is expected to be the same as the *declared* 211 * uncompressed length of the zip entry. It is an error if the *actual* 212 * number of uncompressed bytes differs from this number. 213 * 214 * Returns 0 on success and negative values on failure. 215 */ 216int32_t ExtractToMemory(ZipArchiveHandle handle, ZipEntry* entry, uint8_t* begin, uint32_t size); 217 218int GetFileDescriptor(const ZipArchiveHandle handle); 219 220const char* ErrorCodeString(int32_t error_code); 221 222#if !defined(_WIN32) 223typedef bool (*ProcessZipEntryFunction)(const uint8_t* buf, size_t buf_size, void* cookie); 224 225/* 226 * Stream the uncompressed data through the supplied function, 227 * passing cookie to it each time it gets called. 228 */ 229int32_t ProcessZipEntryContents(ZipArchiveHandle handle, ZipEntry* entry, 230 ProcessZipEntryFunction func, void* cookie); 231#endif 232 233#endif // LIBZIPARCHIVE_ZIPARCHIVE_H_ 234