1 /* 2 * openfs.c --- open an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include <stdio.h> 13 #include <string.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 #include <fcntl.h> 18 #include <time.h> 19 #if HAVE_SYS_STAT_H 20 #include <sys/stat.h> 21 #endif 22 #if HAVE_SYS_TYPES_H 23 #include <sys/types.h> 24 #endif 25 26 #include "ext2_fs.h" 27 28 29 #include "ext2fs.h" 30 #include "e2image.h" 31 32 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 33 { 34 int bg; 35 int has_super = 0; 36 int ret_blk; 37 38 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || 39 (i < fs->super->s_first_meta_bg)) 40 return (group_block + i + 1); 41 42 bg = EXT2_DESC_PER_BLOCK(fs->super) * i; 43 if (ext2fs_bg_has_super(fs, bg)) 44 has_super = 1; 45 ret_blk = ext2fs_group_first_block(fs, bg) + has_super; 46 /* 47 * If group_block is not the normal value, we're trying to use 48 * the backup group descriptors and superblock --- so use the 49 * alternate location of the second block group in the 50 * metablock group. Ideally we should be testing each bg 51 * descriptor block individually for correctness, but we don't 52 * have the infrastructure in place to do that. 53 */ 54 if (group_block != fs->super->s_first_data_block && 55 ((ret_blk + fs->super->s_blocks_per_group) < 56 fs->super->s_blocks_count)) 57 ret_blk += fs->super->s_blocks_per_group; 58 return ret_blk; 59 } 60 61 errcode_t ext2fs_open(const char *name, int flags, int superblock, 62 unsigned int block_size, io_manager manager, 63 ext2_filsys *ret_fs) 64 { 65 return ext2fs_open2(name, 0, flags, superblock, block_size, 66 manager, ret_fs); 67 } 68 69 /* 70 * Note: if superblock is non-zero, block-size must also be non-zero. 71 * Superblock and block_size can be zero to use the default size. 72 * 73 * Valid flags for ext2fs_open() 74 * 75 * EXT2_FLAG_RW - Open the filesystem for read/write. 76 * EXT2_FLAG_FORCE - Open the filesystem even if some of the 77 * features aren't supported. 78 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 79 */ 80 errcode_t ext2fs_open2(const char *name, const char *io_options, 81 int flags, int superblock, 82 unsigned int block_size, io_manager manager, 83 ext2_filsys *ret_fs) 84 { 85 ext2_filsys fs; 86 errcode_t retval; 87 unsigned long i, first_meta_bg; 88 __u32 features; 89 int groups_per_block, blocks_per_group, io_flags; 90 blk_t group_block, blk; 91 char *dest, *cp; 92 #ifdef WORDS_BIGENDIAN 93 struct ext2_group_desc *gdp; 94 int j; 95 #endif 96 97 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 98 99 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 100 if (retval) 101 return retval; 102 103 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 104 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 105 fs->flags = flags; 106 /* don't overwrite sb backups unless flag is explicitly cleared */ 107 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 108 fs->umask = 022; 109 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 110 if (retval) 111 goto cleanup; 112 strcpy(fs->device_name, name); 113 cp = strchr(fs->device_name, '?'); 114 if (!io_options && cp) { 115 *cp++ = 0; 116 io_options = cp; 117 } 118 119 io_flags = 0; 120 if (flags & EXT2_FLAG_RW) 121 io_flags |= IO_FLAG_RW; 122 if (flags & EXT2_FLAG_EXCLUSIVE) 123 io_flags |= IO_FLAG_EXCLUSIVE; 124 if (flags & EXT2_FLAG_DIRECT_IO) 125 io_flags |= IO_FLAG_DIRECT_IO; 126 retval = manager->open(fs->device_name, io_flags, &fs->io); 127 if (retval) 128 goto cleanup; 129 if (io_options && 130 (retval = io_channel_set_options(fs->io, io_options))) 131 goto cleanup; 132 fs->image_io = fs->io; 133 fs->io->app_data = fs; 134 retval = ext2fs_get_memalign(SUPERBLOCK_SIZE, 512, &fs->super); 135 if (retval) 136 goto cleanup; 137 if (flags & EXT2_FLAG_IMAGE_FILE) { 138 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 139 &fs->image_header); 140 if (retval) 141 goto cleanup; 142 retval = io_channel_read_blk(fs->io, 0, 143 -(int)sizeof(struct ext2_image_hdr), 144 fs->image_header); 145 if (retval) 146 goto cleanup; 147 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 148 return EXT2_ET_MAGIC_E2IMAGE; 149 superblock = 1; 150 block_size = fs->image_header->fs_blocksize; 151 } 152 153 /* 154 * If the user specifies a specific block # for the 155 * superblock, then he/she must also specify the block size! 156 * Otherwise, read the master superblock located at offset 157 * SUPERBLOCK_OFFSET from the start of the partition. 158 * 159 * Note: we only save a backup copy of the superblock if we 160 * are reading the superblock from the primary superblock location. 161 */ 162 if (superblock) { 163 if (!block_size) { 164 retval = EXT2_ET_INVALID_ARGUMENT; 165 goto cleanup; 166 } 167 io_channel_set_blksize(fs->io, block_size); 168 group_block = superblock; 169 fs->orig_super = 0; 170 } else { 171 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 172 superblock = 1; 173 group_block = 0; 174 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 175 if (retval) 176 goto cleanup; 177 } 178 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 179 fs->super); 180 if (retval) 181 goto cleanup; 182 if (fs->orig_super) 183 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 184 185 #ifdef WORDS_BIGENDIAN 186 fs->flags |= EXT2_FLAG_SWAP_BYTES; 187 ext2fs_swap_super(fs->super); 188 #else 189 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 190 retval = EXT2_ET_UNIMPLEMENTED; 191 goto cleanup; 192 } 193 #endif 194 195 if (fs->super->s_magic != EXT2_SUPER_MAGIC) { 196 retval = EXT2_ET_BAD_MAGIC; 197 goto cleanup; 198 } 199 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 200 retval = EXT2_ET_REV_TOO_HIGH; 201 goto cleanup; 202 } 203 204 /* 205 * Check for feature set incompatibility 206 */ 207 if (!(flags & EXT2_FLAG_FORCE)) { 208 features = fs->super->s_feature_incompat; 209 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 210 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 211 features &= !EXT2_LIB_SOFTSUPP_INCOMPAT; 212 #endif 213 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 214 retval = EXT2_ET_UNSUPP_FEATURE; 215 goto cleanup; 216 } 217 218 features = fs->super->s_feature_ro_compat; 219 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 220 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 221 features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT; 222 #endif 223 if ((flags & EXT2_FLAG_RW) && 224 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 225 retval = EXT2_ET_RO_UNSUPP_FEATURE; 226 goto cleanup; 227 } 228 229 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 230 (fs->super->s_feature_incompat & 231 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { 232 retval = EXT2_ET_UNSUPP_FEATURE; 233 goto cleanup; 234 } 235 } 236 237 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 238 EXT2_MAX_BLOCK_LOG_SIZE) { 239 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 240 goto cleanup; 241 } 242 fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 243 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 244 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 245 goto cleanup; 246 } 247 fs->fragsize = EXT2_FRAG_SIZE(fs->super); 248 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 249 EXT2_INODE_SIZE(fs->super) + 250 EXT2_BLOCK_SIZE(fs->super) - 1) / 251 EXT2_BLOCK_SIZE(fs->super)); 252 if (block_size) { 253 if (block_size != fs->blocksize) { 254 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 255 goto cleanup; 256 } 257 } 258 /* 259 * Set the blocksize to the filesystem's blocksize. 260 */ 261 io_channel_set_blksize(fs->io, fs->blocksize); 262 263 /* 264 * If this is an external journal device, don't try to read 265 * the group descriptors, because they're not there. 266 */ 267 if (fs->super->s_feature_incompat & 268 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 269 fs->group_desc_count = 0; 270 *ret_fs = fs; 271 return 0; 272 } 273 274 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 275 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 276 goto cleanup; 277 } 278 279 /* 280 * Read group descriptors 281 */ 282 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 283 if (blocks_per_group == 0 || 284 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 285 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 286 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 287 fs->super->s_first_data_block >= fs->super->s_blocks_count) { 288 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 289 goto cleanup; 290 } 291 fs->group_desc_count = ext2fs_div_ceil(fs->super->s_blocks_count - 292 fs->super->s_first_data_block, 293 blocks_per_group); 294 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 295 fs->super->s_inodes_count) { 296 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 297 goto cleanup; 298 } 299 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 300 EXT2_DESC_PER_BLOCK(fs->super)); 301 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 302 &fs->group_desc); 303 if (retval) 304 goto cleanup; 305 if (!group_block) 306 group_block = fs->super->s_first_data_block; 307 dest = (char *) fs->group_desc; 308 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 309 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 310 first_meta_bg = fs->super->s_first_meta_bg; 311 else 312 first_meta_bg = fs->desc_blocks; 313 if (first_meta_bg) { 314 retval = io_channel_read_blk(fs->io, group_block+1, 315 first_meta_bg, dest); 316 if (retval) 317 goto cleanup; 318 #ifdef WORDS_BIGENDIAN 319 gdp = (struct ext2_group_desc *) dest; 320 for (j=0; j < groups_per_block*first_meta_bg; j++) 321 ext2fs_swap_group_desc(gdp++); 322 #endif 323 dest += fs->blocksize*first_meta_bg; 324 } 325 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 326 blk = ext2fs_descriptor_block_loc(fs, group_block, i); 327 retval = io_channel_read_blk(fs->io, blk, 1, dest); 328 if (retval) 329 goto cleanup; 330 #ifdef WORDS_BIGENDIAN 331 gdp = (struct ext2_group_desc *) dest; 332 for (j=0; j < groups_per_block; j++) 333 ext2fs_swap_group_desc(gdp++); 334 #endif 335 dest += fs->blocksize; 336 } 337 338 fs->stride = fs->super->s_raid_stride; 339 340 /* 341 * If recovery is from backup superblock, Clear _UNININT flags & 342 * reset bg_itable_unused to zero 343 */ 344 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 345 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { 346 struct ext2_group_desc *gd; 347 for (i = 0, gd = fs->group_desc; i < fs->group_desc_count; 348 i++, gd++) { 349 gd->bg_flags &= ~EXT2_BG_BLOCK_UNINIT; 350 gd->bg_flags &= ~EXT2_BG_INODE_UNINIT; 351 gd->bg_itable_unused = 0; 352 } 353 ext2fs_mark_super_dirty(fs); 354 } 355 356 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 357 *ret_fs = fs; 358 return 0; 359 cleanup: 360 if (flags & EXT2_FLAG_NOFREE_ON_ERROR) 361 *ret_fs = fs; 362 else 363 ext2fs_free(fs); 364 return retval; 365 } 366 367 /* 368 * Set/get the filesystem data I/O channel. 369 * 370 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 371 */ 372 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 373 { 374 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 375 return EXT2_ET_NOT_IMAGE_FILE; 376 if (old_io) { 377 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 378 } 379 return 0; 380 } 381 382 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 383 { 384 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 385 return EXT2_ET_NOT_IMAGE_FILE; 386 fs->io = new_io ? new_io : fs->image_io; 387 return 0; 388 } 389 390 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 391 { 392 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 393 return EXT2_ET_NOT_IMAGE_FILE; 394 fs->io = fs->image_io = new_io; 395 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 396 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 397 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 398 return 0; 399 } 400
