Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 1 | /* |
| 2 | * image.c --- writes out the critical parts of the filesystem as a |
| 3 | * flat file. |
| 4 | * |
| 5 | * Copyright (C) 2000 Theodore Ts'o. |
| 6 | * |
| 7 | * Note: this uses the POSIX IO interfaces, unlike most of the other |
| 8 | * functions in this library. So sue me. |
| 9 | * |
| 10 | * %Begin-Header% |
| 11 | * This file may be redistributed under the terms of the GNU Public |
| 12 | * License. |
| 13 | * %End-Header% |
| 14 | */ |
| 15 | |
| 16 | #include <stdio.h> |
| 17 | #include <string.h> |
| 18 | #if HAVE_UNISTD_H |
| 19 | #include <unistd.h> |
| 20 | #endif |
| 21 | #if HAVE_ERRNO_H |
| 22 | #include <errno.h> |
| 23 | #endif |
| 24 | #include <fcntl.h> |
| 25 | #include <time.h> |
| 26 | #if HAVE_SYS_STAT_H |
| 27 | #include <sys/stat.h> |
| 28 | #endif |
| 29 | #if HAVE_SYS_TYPES_H |
| 30 | #include <sys/types.h> |
| 31 | #endif |
| 32 | |
| 33 | #include "ext2_fs.h" |
| 34 | #include "ext2fs.h" |
| 35 | |
| 36 | #ifndef HAVE_TYPE_SSIZE_T |
| 37 | typedef int ssize_t; |
| 38 | #endif |
| 39 | |
| 40 | /* |
| 41 | * This function returns 1 if the specified block is all zeros |
| 42 | */ |
| 43 | static int check_zero_block(char *buf, int blocksize) |
| 44 | { |
| 45 | char *cp = buf; |
| 46 | int left = blocksize; |
| 47 | |
| 48 | while (left > 0) { |
| 49 | if (*cp++) |
| 50 | return 0; |
| 51 | left--; |
| 52 | } |
| 53 | return 1; |
| 54 | } |
| 55 | |
| 56 | /* |
| 57 | * Write the inode table out as a single block. |
| 58 | */ |
| 59 | #define BUF_BLOCKS 32 |
| 60 | |
| 61 | errcode_t ext2fs_image_inode_write(ext2_filsys fs, int fd, int flags) |
| 62 | { |
| 63 | unsigned int group, left, c, d; |
| 64 | char *buf, *cp; |
| 65 | blk_t blk; |
| 66 | ssize_t actual; |
| 67 | errcode_t retval; |
| 68 | |
Mike Frysinger | d582690 | 2005-06-12 00:45:09 +0000 | [diff] [blame^] | 69 | buf = xmalloc(fs->blocksize * BUF_BLOCKS); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 70 | |
| 71 | for (group = 0; group < fs->group_desc_count; group++) { |
| 72 | blk = fs->group_desc[(unsigned)group].bg_inode_table; |
| 73 | if (!blk) |
| 74 | return EXT2_ET_MISSING_INODE_TABLE; |
| 75 | left = fs->inode_blocks_per_group; |
| 76 | while (left) { |
| 77 | c = BUF_BLOCKS; |
| 78 | if (c > left) |
| 79 | c = left; |
| 80 | retval = io_channel_read_blk(fs->io, blk, c, buf); |
| 81 | if (retval) |
| 82 | goto errout; |
| 83 | cp = buf; |
| 84 | while (c) { |
| 85 | if (!(flags & IMAGER_FLAG_SPARSEWRITE)) { |
| 86 | d = c; |
| 87 | goto skip_sparse; |
| 88 | } |
| 89 | /* Skip zero blocks */ |
| 90 | if (check_zero_block(cp, fs->blocksize)) { |
| 91 | c--; |
| 92 | blk++; |
| 93 | left--; |
| 94 | cp += fs->blocksize; |
| 95 | lseek(fd, fs->blocksize, SEEK_CUR); |
| 96 | continue; |
| 97 | } |
| 98 | /* Find non-zero blocks */ |
| 99 | for (d=1; d < c; d++) { |
| 100 | if (check_zero_block(cp + d*fs->blocksize, fs->blocksize)) |
| 101 | break; |
| 102 | } |
| 103 | skip_sparse: |
| 104 | actual = write(fd, cp, fs->blocksize * d); |
| 105 | if (actual == -1) { |
| 106 | retval = errno; |
| 107 | goto errout; |
| 108 | } |
| 109 | if (actual != (ssize_t) (fs->blocksize * d)) { |
| 110 | retval = EXT2_ET_SHORT_WRITE; |
| 111 | goto errout; |
| 112 | } |
| 113 | blk += d; |
| 114 | left -= d; |
| 115 | cp += fs->blocksize * d; |
| 116 | c -= d; |
| 117 | } |
| 118 | } |
| 119 | } |
| 120 | retval = 0; |
| 121 | |
| 122 | errout: |
| 123 | free(buf); |
| 124 | return retval; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Read in the inode table and stuff it into place |
| 129 | */ |
| 130 | errcode_t ext2fs_image_inode_read(ext2_filsys fs, int fd, |
| 131 | int flags EXT2FS_ATTR((unused))) |
| 132 | { |
| 133 | unsigned int group, c, left; |
| 134 | char *buf; |
| 135 | blk_t blk; |
| 136 | ssize_t actual; |
| 137 | errcode_t retval; |
| 138 | |
Mike Frysinger | d582690 | 2005-06-12 00:45:09 +0000 | [diff] [blame^] | 139 | buf = xmalloc(fs->blocksize * BUF_BLOCKS); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 140 | |
| 141 | for (group = 0; group < fs->group_desc_count; group++) { |
| 142 | blk = fs->group_desc[(unsigned)group].bg_inode_table; |
| 143 | if (!blk) { |
| 144 | retval = EXT2_ET_MISSING_INODE_TABLE; |
| 145 | goto errout; |
| 146 | } |
| 147 | left = fs->inode_blocks_per_group; |
| 148 | while (left) { |
| 149 | c = BUF_BLOCKS; |
| 150 | if (c > left) |
| 151 | c = left; |
| 152 | actual = read(fd, buf, fs->blocksize * c); |
| 153 | if (actual == -1) { |
| 154 | retval = errno; |
| 155 | goto errout; |
| 156 | } |
| 157 | if (actual != (ssize_t) (fs->blocksize * c)) { |
| 158 | retval = EXT2_ET_SHORT_READ; |
| 159 | goto errout; |
| 160 | } |
| 161 | retval = io_channel_write_blk(fs->io, blk, c, buf); |
| 162 | if (retval) |
| 163 | goto errout; |
| 164 | |
| 165 | blk += c; |
| 166 | left -= c; |
| 167 | } |
| 168 | } |
| 169 | retval = ext2fs_flush_icache(fs); |
| 170 | |
| 171 | errout: |
| 172 | free(buf); |
| 173 | return retval; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * Write out superblock and group descriptors |
| 178 | */ |
| 179 | errcode_t ext2fs_image_super_write(ext2_filsys fs, int fd, |
| 180 | int flags EXT2FS_ATTR((unused))) |
| 181 | { |
| 182 | char *buf, *cp; |
| 183 | ssize_t actual; |
| 184 | errcode_t retval; |
| 185 | |
Mike Frysinger | d582690 | 2005-06-12 00:45:09 +0000 | [diff] [blame^] | 186 | buf = xmalloc(fs->blocksize); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 187 | |
| 188 | /* |
| 189 | * Write out the superblock |
| 190 | */ |
| 191 | memset(buf, 0, fs->blocksize); |
| 192 | memcpy(buf, fs->super, SUPERBLOCK_SIZE); |
| 193 | actual = write(fd, buf, fs->blocksize); |
| 194 | if (actual == -1) { |
| 195 | retval = errno; |
| 196 | goto errout; |
| 197 | } |
| 198 | if (actual != (ssize_t) fs->blocksize) { |
| 199 | retval = EXT2_ET_SHORT_WRITE; |
| 200 | goto errout; |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Now write out the block group descriptors |
| 205 | */ |
| 206 | cp = (char *) fs->group_desc; |
| 207 | actual = write(fd, cp, fs->blocksize * fs->desc_blocks); |
| 208 | if (actual == -1) { |
| 209 | retval = errno; |
| 210 | goto errout; |
| 211 | } |
| 212 | if (actual != (ssize_t) (fs->blocksize * fs->desc_blocks)) { |
| 213 | retval = EXT2_ET_SHORT_WRITE; |
| 214 | goto errout; |
| 215 | } |
| 216 | |
| 217 | retval = 0; |
| 218 | |
| 219 | errout: |
| 220 | free(buf); |
| 221 | return retval; |
| 222 | } |
| 223 | |
| 224 | /* |
| 225 | * Read the superblock and group descriptors and overwrite them. |
| 226 | */ |
| 227 | errcode_t ext2fs_image_super_read(ext2_filsys fs, int fd, |
| 228 | int flags EXT2FS_ATTR((unused))) |
| 229 | { |
| 230 | char *buf; |
| 231 | ssize_t actual, size; |
| 232 | errcode_t retval; |
| 233 | |
| 234 | size = fs->blocksize * (fs->group_desc_count + 1); |
Mike Frysinger | d582690 | 2005-06-12 00:45:09 +0000 | [diff] [blame^] | 235 | buf = xmalloc(size); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 236 | |
| 237 | /* |
| 238 | * Read it all in. |
| 239 | */ |
| 240 | actual = read(fd, buf, size); |
| 241 | if (actual == -1) { |
| 242 | retval = errno; |
| 243 | goto errout; |
| 244 | } |
| 245 | if (actual != size) { |
| 246 | retval = EXT2_ET_SHORT_READ; |
| 247 | goto errout; |
| 248 | } |
| 249 | |
| 250 | /* |
| 251 | * Now copy in the superblock and group descriptors |
| 252 | */ |
| 253 | memcpy(fs->super, buf, SUPERBLOCK_SIZE); |
| 254 | |
| 255 | memcpy(fs->group_desc, buf + fs->blocksize, |
| 256 | fs->blocksize * fs->group_desc_count); |
| 257 | |
| 258 | retval = 0; |
| 259 | |
| 260 | errout: |
| 261 | free(buf); |
| 262 | return retval; |
| 263 | } |
| 264 | |
| 265 | /* |
| 266 | * Write the block/inode bitmaps. |
| 267 | */ |
| 268 | errcode_t ext2fs_image_bitmap_write(ext2_filsys fs, int fd, int flags) |
| 269 | { |
| 270 | char *ptr; |
| 271 | int c, size; |
| 272 | char zero_buf[1024]; |
| 273 | ssize_t actual; |
| 274 | errcode_t retval; |
| 275 | |
| 276 | if (flags & IMAGER_FLAG_INODEMAP) { |
| 277 | if (!fs->inode_map) { |
| 278 | retval = ext2fs_read_inode_bitmap(fs); |
| 279 | if (retval) |
| 280 | return retval; |
| 281 | } |
| 282 | ptr = fs->inode_map->bitmap; |
| 283 | size = (EXT2_INODES_PER_GROUP(fs->super) / 8); |
| 284 | } else { |
| 285 | if (!fs->block_map) { |
| 286 | retval = ext2fs_read_block_bitmap(fs); |
| 287 | if (retval) |
| 288 | return retval; |
| 289 | } |
| 290 | ptr = fs->block_map->bitmap; |
| 291 | size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; |
| 292 | } |
| 293 | size = size * fs->group_desc_count; |
| 294 | |
| 295 | actual = write(fd, ptr, size); |
| 296 | if (actual == -1) { |
| 297 | retval = errno; |
| 298 | goto errout; |
| 299 | } |
| 300 | if (actual != size) { |
| 301 | retval = EXT2_ET_SHORT_WRITE; |
| 302 | goto errout; |
| 303 | } |
| 304 | size = size % fs->blocksize; |
| 305 | memset(zero_buf, 0, sizeof(zero_buf)); |
| 306 | if (size) { |
| 307 | size = fs->blocksize - size; |
| 308 | while (size) { |
| 309 | c = size; |
| 310 | if (c > (int) sizeof(zero_buf)) |
| 311 | c = sizeof(zero_buf); |
| 312 | actual = write(fd, zero_buf, c); |
| 313 | if (actual == -1) { |
| 314 | retval = errno; |
| 315 | goto errout; |
| 316 | } |
| 317 | if (actual != c) { |
| 318 | retval = EXT2_ET_SHORT_WRITE; |
| 319 | goto errout; |
| 320 | } |
| 321 | size -= c; |
| 322 | } |
| 323 | } |
| 324 | retval = 0; |
| 325 | errout: |
| 326 | return (retval); |
| 327 | } |
| 328 | |
| 329 | |
| 330 | /* |
| 331 | * Read the block/inode bitmaps. |
| 332 | */ |
| 333 | errcode_t ext2fs_image_bitmap_read(ext2_filsys fs, int fd, int flags) |
| 334 | { |
| 335 | char *ptr, *buf = 0; |
| 336 | int size; |
| 337 | ssize_t actual; |
| 338 | errcode_t retval; |
| 339 | |
| 340 | if (flags & IMAGER_FLAG_INODEMAP) { |
| 341 | if (!fs->inode_map) { |
| 342 | retval = ext2fs_read_inode_bitmap(fs); |
| 343 | if (retval) |
| 344 | return retval; |
| 345 | } |
| 346 | ptr = fs->inode_map->bitmap; |
| 347 | size = (EXT2_INODES_PER_GROUP(fs->super) / 8); |
| 348 | } else { |
| 349 | if (!fs->block_map) { |
| 350 | retval = ext2fs_read_block_bitmap(fs); |
| 351 | if (retval) |
| 352 | return retval; |
| 353 | } |
| 354 | ptr = fs->block_map->bitmap; |
| 355 | size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; |
| 356 | } |
| 357 | size = size * fs->group_desc_count; |
| 358 | |
Mike Frysinger | d582690 | 2005-06-12 00:45:09 +0000 | [diff] [blame^] | 359 | buf = xmalloc(size); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 360 | |
| 361 | actual = read(fd, buf, size); |
| 362 | if (actual == -1) { |
| 363 | retval = errno; |
| 364 | goto errout; |
| 365 | } |
| 366 | if (actual != size) { |
| 367 | retval = EXT2_ET_SHORT_WRITE; |
| 368 | goto errout; |
| 369 | } |
| 370 | memcpy(ptr, buf, size); |
| 371 | |
| 372 | retval = 0; |
| 373 | errout: |
| 374 | if (buf) |
| 375 | free(buf); |
| 376 | return (retval); |
| 377 | } |