[821] | 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 |
|
---|
| 69 | buf = xmalloc(fs->blocksize * BUF_BLOCKS);
|
---|
| 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 |
|
---|
| 139 | buf = xmalloc(fs->blocksize * BUF_BLOCKS);
|
---|
| 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 |
|
---|
| 186 | buf = xmalloc(fs->blocksize);
|
---|
| 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);
|
---|
| 235 | buf = xmalloc(size);
|
---|
| 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 |
|
---|
| 359 | buf = xmalloc(size);
|
---|
| 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 | free(buf);
|
---|
| 375 | return (retval);
|
---|
| 376 | }
|
---|