1 /* 2 * Copyright (C) 2012 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 _LIBSPARSE_SPARSE_H_ 18 #define _LIBSPARSE_SPARSE_H_ 19 20 #include <stdbool.h> 21 #include <stddef.h> 22 #include <stdint.h> 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif 27 28 struct sparse_file; 29 30 // The callbacks in sparse_file_callback() and sparse_file_foreach_chunk() take 31 // size_t as the length type (was `int` in past). This allows clients to keep 32 // their codes compatibile with both versions as needed. 33 #define SPARSE_CALLBACK_USES_SIZE_T 34 35 /** 36 * sparse_file_new - create a new sparse file cookie 37 * 38 * @block_size - minimum size of a chunk 39 * @len - size of the expanded sparse file. 40 * 41 * Creates a new sparse_file cookie that can be used to associate data 42 * blocks. Can later be written to a file with a variety of options. 43 * block_size specifies the minimum size of a chunk in the file. The maximum 44 * size of the file is 2**32 * block_size (16TB for 4k block size). 45 * 46 * Returns the sparse file cookie, or NULL on error. 47 */ 48 struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len); 49 50 /** 51 * sparse_file_destroy - destroy a sparse file cookie 52 * 53 * @s - sparse file cookie 54 * 55 * Destroys a sparse file cookie. After destroy, all memory passed in to 56 * sparse_file_add_data can be freed by the caller 57 */ 58 void sparse_file_destroy(struct sparse_file *s); 59 60 /** 61 * sparse_file_add_data - associate a data chunk with a sparse file 62 * 63 * @s - sparse file cookie 64 * @data - pointer to data block 65 * @len - length of the data block 66 * @block - offset in blocks into the sparse file to place the data chunk 67 * 68 * Associates a data chunk with a sparse file cookie. The region 69 * [block * block_size : block * block_size + len) must not already be used in 70 * the sparse file. If len is not a multiple of the block size the data 71 * will be padded with zeros. 72 * 73 * The data pointer must remain valid until the sparse file is closed or the 74 * data block is removed from the sparse file. 75 * 76 * Returns 0 on success, negative errno on error. 77 */ 78 int sparse_file_add_data(struct sparse_file *s, 79 void *data, unsigned int len, unsigned int block); 80 81 /** 82 * sparse_file_add_fill - associate a fill chunk with a sparse file 83 * 84 * @s - sparse file cookie 85 * @fill_val - 32 bit fill data 86 * @len - length of the fill block 87 * @block - offset in blocks into the sparse file to place the fill chunk 88 * 89 * Associates a chunk filled with fill_val with a sparse file cookie. 90 * The region [block * block_size : block * block_size + len) must not already 91 * be used in the sparse file. If len is not a multiple of the block size the 92 * data will be padded with zeros. 93 * 94 * Returns 0 on success, negative errno on error. 95 */ 96 int sparse_file_add_fill(struct sparse_file *s, 97 uint32_t fill_val, unsigned int len, unsigned int block); 98 99 /** 100 * sparse_file_add_file - associate a chunk of a file with a sparse file 101 * 102 * @s - sparse file cookie 103 * @filename - filename of the file to be copied 104 * @file_offset - offset into the copied file 105 * @len - length of the copied block 106 * @block - offset in blocks into the sparse file to place the file chunk 107 * 108 * Associates a chunk of an existing file with a sparse file cookie. 109 * The region [block * block_size : block * block_size + len) must not already 110 * be used in the sparse file. If len is not a multiple of the block size the 111 * data will be padded with zeros. 112 * 113 * Allows adding large amounts of data to a sparse file without needing to keep 114 * it all mapped. File size is limited by available virtual address space, 115 * exceptionally large files may need to be added in multiple chunks. 116 * 117 * Returns 0 on success, negative errno on error. 118 */ 119 int sparse_file_add_file(struct sparse_file *s, 120 const char *filename, int64_t file_offset, unsigned int len, 121 unsigned int block); 122 123 /** 124 * sparse_file_add_file - associate a chunk of a file with a sparse file 125 * 126 * @s - sparse file cookie 127 * @filename - filename of the file to be copied 128 * @file_offset - offset into the copied file 129 * @len - length of the copied block 130 * @block - offset in blocks into the sparse file to place the file chunk 131 * 132 * Associates a chunk of an existing fd with a sparse file cookie. 133 * The region [block * block_size : block * block_size + len) must not already 134 * be used in the sparse file. If len is not a multiple of the block size the 135 * data will be padded with zeros. 136 * 137 * Allows adding large amounts of data to a sparse file without needing to keep 138 * it all mapped. File size is limited by available virtual address space, 139 * exceptionally large files may need to be added in multiple chunks. 140 * 141 * The fd must remain open until the sparse file is closed or the fd block is 142 * removed from the sparse file. 143 * 144 * Returns 0 on success, negative errno on error. 145 */ 146 int sparse_file_add_fd(struct sparse_file *s, 147 int fd, int64_t file_offset, unsigned int len, unsigned int block); 148 149 /** 150 * sparse_file_write - write a sparse file to a file 151 * 152 * @s - sparse file cookie 153 * @fd - file descriptor to write to 154 * @gz - write a gzipped file 155 * @sparse - write in the Android sparse file format 156 * @crc - append a crc chunk 157 * 158 * Writes a sparse file to a file. If gz is true, the data will be passed 159 * through zlib. If sparse is true, the file will be written in the Android 160 * sparse file format. If sparse is false, the file will be written by seeking 161 * over unused chunks, producing a smaller file if the filesystem supports 162 * sparse files. If crc is true, the crc of the expanded data will be 163 * calculated and appended in a crc chunk. 164 * 165 * Returns 0 on success, negative errno on error. 166 */ 167 int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse, 168 bool crc); 169 170 /** 171 * sparse_file_len - return the length of a sparse file if written to disk 172 * 173 * @s - sparse file cookie 174 * @sparse - write in the Android sparse file format 175 * @crc - append a crc chunk 176 * 177 * Returns the size a sparse file would be on disk if it were written in the 178 * specified format. If sparse is true, this is the size of the data in the 179 * sparse format. If sparse is false, this is the size of the normal 180 * non-sparse file. 181 */ 182 int64_t sparse_file_len(struct sparse_file *s, bool sparse, bool crc); 183 184 /** 185 * sparse_file_block_size 186 * 187 * @s - sparse file cookie 188 */ 189 unsigned int sparse_file_block_size(struct sparse_file *s); 190 191 /** 192 * sparse_file_callback - call a callback for blocks in sparse file 193 * 194 * @s - sparse file cookie 195 * @sparse - write in the Android sparse file format 196 * @crc - append a crc chunk 197 * @write - function to call for each block 198 * @priv - value that will be passed as the first argument to write 199 * 200 * Writes a sparse file by calling a callback function. If sparse is true, the 201 * file will be written in the Android sparse file format. If crc is true, the 202 * crc of the expanded data will be calculated and appended in a crc chunk. 203 * The callback 'write' will be called with data and length for each data, 204 * and with data==NULL to skip over a region (only used for non-sparse format). 205 * The callback should return negative on error, 0 on success. 206 * 207 * Returns 0 on success, negative errno on error. 208 */ 209 int sparse_file_callback(struct sparse_file *s, bool sparse, bool crc, 210 int (*write)(void *priv, const void *data, size_t len), void *priv); 211 212 /** 213 * sparse_file_foreach_chunk - call a callback for data blocks in sparse file 214 * 215 * @s - sparse file cookie 216 * @sparse - write in the Android sparse file format 217 * @crc - append a crc chunk 218 * @write - function to call for each block 219 * @priv - value that will be passed as the first argument to write 220 * 221 * The function has the same behavior as 'sparse_file_callback', except it only 222 * iterates on blocks that contain data. 223 * 224 * Returns 0 on success, negative errno on error. 225 */ 226 int sparse_file_foreach_chunk(struct sparse_file *s, bool sparse, bool crc, 227 int (*write)(void *priv, const void *data, size_t len, unsigned int block, 228 unsigned int nr_blocks), 229 void *priv); 230 /** 231 * sparse_file_read - read a file into a sparse file cookie 232 * 233 * @s - sparse file cookie 234 * @fd - file descriptor to read from 235 * @sparse - read a file in the Android sparse file format 236 * @crc - verify the crc of a file in the Android sparse file format 237 * 238 * Reads a file into a sparse file cookie. If sparse is true, the file is 239 * assumed to be in the Android sparse file format. If sparse is false, the 240 * file will be sparsed by looking for block aligned chunks of all zeros or 241 * another 32 bit value. If crc is true, the crc of the sparse file will be 242 * verified. 243 * 244 * Returns 0 on success, negative errno on error. 245 */ 246 int sparse_file_read(struct sparse_file *s, int fd, bool sparse, bool crc); 247 248 /** 249 * sparse_file_read_buf - read a buffer into a sparse file cookie 250 * 251 * @s - sparse file cookie 252 * @buf - buffer to read from 253 * @crc - verify the crc of a file in the Android sparse file format 254 * 255 * Reads a buffer into a sparse file cookie. The buffer must remain 256 * valid until the sparse file cookie is freed. If crc is true, the 257 * crc of the sparse file will be verified. 258 * 259 * Returns 0 on success, negative errno on error. 260 */ 261 int sparse_file_read_buf(struct sparse_file *s, char *buf, bool crc); 262 263 /** 264 * sparse_file_import - import an existing sparse file 265 * 266 * @fd - file descriptor to read from 267 * @verbose - print verbose errors while reading the sparse file 268 * @crc - verify the crc of a file in the Android sparse file format 269 * 270 * Reads an existing sparse file into a sparse file cookie, recreating the same 271 * sparse cookie that was used to write it. If verbose is true, prints verbose 272 * errors when the sparse file is formatted incorrectly. 273 * 274 * Returns a new sparse file cookie on success, NULL on error. 275 */ 276 struct sparse_file *sparse_file_import(int fd, bool verbose, bool crc); 277 278 /** 279 * sparse_file_import_buf - import an existing sparse file from a buffer 280 * 281 * @buf - buffer to read from 282 * @verbose - print verbose errors while reading the sparse file 283 * @crc - verify the crc of a file in the Android sparse file format 284 * 285 * Reads existing sparse file data into a sparse file cookie, recreating the same 286 * sparse cookie that was used to write it. If verbose is true, prints verbose 287 * errors when the sparse file is formatted incorrectly. 288 * 289 * Returns a new sparse file cookie on success, NULL on error. 290 */ 291 struct sparse_file *sparse_file_import_buf(char* buf, bool verbose, bool crc); 292 293 /** 294 * sparse_file_import_auto - import an existing sparse or normal file 295 * 296 * @fd - file descriptor to read from 297 * @crc - verify the crc of a file in the Android sparse file format 298 * @verbose - whether to use verbose logging 299 * 300 * Reads an existing sparse or normal file into a sparse file cookie. 301 * Attempts to determine if the file is sparse or not by looking for the sparse 302 * file magic number in the first 4 bytes. If the file is not sparse, the file 303 * will be sparsed by looking for block aligned chunks of all zeros or another 304 * 32 bit value. If crc is true, the crc of the sparse file will be verified. 305 * 306 * Returns a new sparse file cookie on success, NULL on error. 307 */ 308 struct sparse_file *sparse_file_import_auto(int fd, bool crc, bool verbose); 309 310 /** sparse_file_resparse - rechunk an existing sparse file into smaller files 311 * 312 * @in_s - sparse file cookie of the existing sparse file 313 * @max_len - maximum file size 314 * @out_s - array of sparse file cookies 315 * @out_s_count - size of out_s array 316 * 317 * Splits chunks of an existing sparse file into smaller sparse files such that 318 * each sparse file is less than max_len. Returns the number of sparse_files 319 * that would have been written to out_s if out_s were big enough. 320 */ 321 int sparse_file_resparse(struct sparse_file *in_s, unsigned int max_len, 322 struct sparse_file **out_s, int out_s_count); 323 324 /** 325 * sparse_file_verbose - set a sparse file cookie to print verbose errors 326 * 327 * @s - sparse file cookie 328 * 329 * Print verbose sparse file errors whenever using the sparse file cookie. 330 */ 331 void sparse_file_verbose(struct sparse_file *s); 332 333 /** 334 * sparse_print_verbose - function called to print verbose errors 335 * 336 * By default, verbose errors will print to standard error. 337 * sparse_print_verbose may be overridden to log verbose errors somewhere else. 338 * 339 */ 340 extern void (*sparse_print_verbose)(const char *fmt, ...); 341 342 #ifdef __cplusplus 343 } 344 #endif 345 346 #endif 347