diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/ext2fs/openfs.c | 590 |
1 files changed, 590 insertions, 0 deletions
diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c new file mode 100644 index 0000000..fd56a9a --- /dev/null +++ b/lib/ext2fs/openfs.c @@ -0,0 +1,590 @@ +/* + * openfs.c --- open an ext2 filesystem + * + * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Library + * General Public License, version 2. + * %End-Header% + */ + +#include "config.h" +#include <stdio.h> +#include <string.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#include <fcntl.h> +#include <time.h> +#if HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#if HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif + +#include "ext2_fs.h" + +#include "ext2fs.h" +#include "e2image.h" + +blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block, + dgrp_t i) +{ + int bg; + int has_super = 0, group_zero_adjust = 0; + blk64_t ret_blk; + + /* + * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4 + * stuff, so adjust for that if we're being asked for group 0. + */ + if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1) + group_zero_adjust = 1; + + if (!ext2fs_has_feature_meta_bg(fs->super) || + (i < fs->super->s_first_meta_bg)) + return group_block + i + 1 + group_zero_adjust; + + bg = EXT2_DESC_PER_BLOCK(fs->super) * i; + if (ext2fs_bg_has_super(fs, bg)) + has_super = 1; + ret_blk = ext2fs_group_first_block2(fs, bg); + /* + * If group_block is not the normal value, we're trying to use + * the backup group descriptors and superblock --- so use the + * alternate location of the second block group in the + * metablock group. Ideally we should be testing each bg + * descriptor block individually for correctness, but we don't + * have the infrastructure in place to do that. + */ + if (group_block != fs->super->s_first_data_block && + ((ret_blk + has_super + fs->super->s_blocks_per_group) < + ext2fs_blocks_count(fs->super))) { + ret_blk += fs->super->s_blocks_per_group; + + /* + * If we're going to jump forward a block group, make sure + * that we adjust has_super to account for the next group's + * backup superblock (or lack thereof). + */ + if (ext2fs_bg_has_super(fs, bg + 1)) + has_super = 1; + else + has_super = 0; + } + return ret_blk + has_super + group_zero_adjust; +} + +blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) +{ + return ext2fs_descriptor_block_loc2(fs, group_block, i); +} + +errcode_t ext2fs_open(const char *name, int flags, int superblock, + unsigned int block_size, io_manager manager, + ext2_filsys *ret_fs) +{ + return ext2fs_open2(name, 0, flags, superblock, block_size, + manager, ret_fs); +} + +static void block_sha_map_free_entry(void *data) +{ + free(data); + return; +} + +/* + * Note: if superblock is non-zero, block-size must also be non-zero. + * Superblock and block_size can be zero to use the default size. + * + * Valid flags for ext2fs_open() + * + * EXT2_FLAG_RW - Open the filesystem for read/write. + * EXT2_FLAG_FORCE - Open the filesystem even if some of the + * features aren't supported. + * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device + * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check. + * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large + * filesystems) + */ +errcode_t ext2fs_open2(const char *name, const char *io_options, + int flags, int superblock, + unsigned int block_size, io_manager manager, + ext2_filsys *ret_fs) +{ + ext2_filsys fs; + errcode_t retval; + unsigned long i, first_meta_bg; + __u32 features; + unsigned int blocks_per_group, io_flags; + blk64_t group_block, blk; + char *dest, *cp; + int group_zero_adjust = 0; + unsigned int inode_size; + __u64 groups_cnt; +#ifdef WORDS_BIGENDIAN + unsigned int groups_per_block; + struct ext2_group_desc *gdp; + int j; +#endif + char *time_env; + int csum_retries = 0; + + EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); + + retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); + if (retval) + return retval; + + memset(fs, 0, sizeof(struct struct_ext2_filsys)); + fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; + fs->flags = flags; + /* don't overwrite sb backups unless flag is explicitly cleared */ + fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; + fs->umask = 022; + + time_env = getenv("E2FSPROGS_FAKE_TIME"); + if (time_env) + fs->now = strtoul(time_env, NULL, 0); + + retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); + if (retval) + goto cleanup; + strcpy(fs->device_name, name); + cp = strchr(fs->device_name, '?'); + if (!io_options && cp) { + *cp++ = 0; + io_options = cp; + } + + io_flags = 0; + if (flags & EXT2_FLAG_RW) + io_flags |= IO_FLAG_RW; + if (flags & EXT2_FLAG_EXCLUSIVE) + io_flags |= IO_FLAG_EXCLUSIVE; + if (flags & EXT2_FLAG_DIRECT_IO) + io_flags |= IO_FLAG_DIRECT_IO; + if (flags & EXT2_FLAG_THREADS) + io_flags |= IO_FLAG_THREADS; + retval = manager->open(fs->device_name, io_flags, &fs->io); + if (retval) + goto cleanup; + if (io_options && + (retval = io_channel_set_options(fs->io, io_options))) + goto cleanup; + fs->image_io = fs->io; + fs->io->app_data = fs; + retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super); + if (retval) + goto cleanup; + if (flags & EXT2_FLAG_IMAGE_FILE) { + retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), + &fs->image_header); + if (retval) + goto cleanup; + retval = io_channel_read_blk(fs->io, 0, + -(int)sizeof(struct ext2_image_hdr), + fs->image_header); + if (retval) + goto cleanup; + if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE) + return EXT2_ET_MAGIC_E2IMAGE; + superblock = 1; + block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize); + } + + /* + * If the user specifies a specific block # for the + * superblock, then he/she must also specify the block size! + * Otherwise, read the master superblock located at offset + * SUPERBLOCK_OFFSET from the start of the partition. + * + * Note: we only save a backup copy of the superblock if we + * are reading the superblock from the primary superblock location. + */ + if (superblock) { + if (!block_size) { + retval = EXT2_ET_INVALID_ARGUMENT; + goto cleanup; + } + io_channel_set_blksize(fs->io, block_size); + group_block = superblock; + fs->orig_super = 0; + } else { + io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); + superblock = 1; + group_block = 0; + retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); + if (retval) + goto cleanup; + } +retry: + retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, + fs->super); + if (retval) + goto cleanup; + if (fs->orig_super) + memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); + + if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { + retval = 0; + if (!ext2fs_verify_csum_type(fs, fs->super)) + retval = EXT2_ET_UNKNOWN_CSUM; + if (!ext2fs_superblock_csum_verify(fs, fs->super)) { + if (csum_retries++ < 3) + goto retry; + retval = EXT2_ET_SB_CSUM_INVALID; + } + } + +#ifdef WORDS_BIGENDIAN + fs->flags |= EXT2_FLAG_SWAP_BYTES; + ext2fs_swap_super(fs->super); +#else + if (fs->flags & EXT2_FLAG_SWAP_BYTES) { + retval = EXT2_ET_UNIMPLEMENTED; + goto cleanup; + } +#endif + + if (fs->super->s_magic != EXT2_SUPER_MAGIC) + retval = EXT2_ET_BAD_MAGIC; + if (retval) + goto cleanup; + + if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { + retval = EXT2_ET_REV_TOO_HIGH; + goto cleanup; + } + + /* + * Check for feature set incompatibility + */ + if (!(flags & EXT2_FLAG_FORCE)) { + features = fs->super->s_feature_incompat; +#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT + if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) + features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT; +#endif + if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { + retval = EXT2_ET_UNSUPP_FEATURE; + goto cleanup; + } + + features = fs->super->s_feature_ro_compat; +#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT + if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) + features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT; +#endif + if ((flags & EXT2_FLAG_RW) && + (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { + retval = EXT2_ET_RO_UNSUPP_FEATURE; + goto cleanup; + } + + if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && + ext2fs_has_feature_journal_dev(fs->super)) { + retval = EXT2_ET_UNSUPP_FEATURE; + goto cleanup; + } + } + + if ((fs->super->s_log_block_size > + (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) || + (fs->super->s_log_cluster_size > + (unsigned) (EXT2_MAX_CLUSTER_LOG_SIZE - EXT2_MIN_CLUSTER_LOG_SIZE)) || + (fs->super->s_log_block_size > fs->super->s_log_cluster_size) || + (fs->super->s_log_groups_per_flex > 31)) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + + /* + * bigalloc requires cluster-aware bitfield operations, which at the + * moment means we need EXT2_FLAG_64BITS. + */ + if (ext2fs_has_feature_bigalloc(fs->super) && + !(flags & EXT2_FLAG_64BITS)) { + retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS; + goto cleanup; + } + + if (!ext2fs_has_feature_bigalloc(fs->super) && + (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super); + inode_size = EXT2_INODE_SIZE(fs->super); + if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) || + (inode_size > fs->blocksize) || + (inode_size & (inode_size - 1))) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + + /* Enforce the block group descriptor size */ + if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) && + ext2fs_has_feature_64bit(fs->super)) { + unsigned desc_size = fs->super->s_desc_size; + + if ((desc_size < EXT2_MIN_DESC_SIZE_64BIT) || + (desc_size > EXT2_MAX_DESC_SIZE) || + (desc_size & (desc_size - 1)) != 0) { + retval = EXT2_ET_BAD_DESC_SIZE; + goto cleanup; + } + } + + fs->cluster_ratio_bits = fs->super->s_log_cluster_size - + fs->super->s_log_block_size; + if (EXT2_BLOCKS_PER_GROUP(fs->super) != + EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * + EXT2_INODE_SIZE(fs->super) + + EXT2_BLOCK_SIZE(fs->super) - 1) / + EXT2_BLOCK_SIZE(fs->super)); + if (block_size) { + if (block_size != fs->blocksize) { + retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; + goto cleanup; + } + } + /* + * Set the blocksize to the filesystem's blocksize. + */ + io_channel_set_blksize(fs->io, fs->blocksize); + + /* + * If this is an external journal device, don't try to read + * the group descriptors, because they're not there. + */ + if (ext2fs_has_feature_journal_dev(fs->super)) { + fs->group_desc_count = 0; + *ret_fs = fs; + return 0; + } + + if (EXT2_INODES_PER_GROUP(fs->super) == 0) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + /* Precompute the FS UUID to seed other checksums */ + ext2fs_init_csum_seed(fs); + + /* + * Read group descriptors + */ + blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); + if (blocks_per_group < 8 || + blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || + fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || + EXT2_DESC_PER_BLOCK(fs->super) == 0 || + fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - + fs->super->s_first_data_block, + blocks_per_group); + if (groups_cnt >> 32) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + fs->group_desc_count = groups_cnt; + if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) && + (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != + fs->super->s_inodes_count) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, + EXT2_DESC_PER_BLOCK(fs->super)); + if (ext2fs_has_feature_meta_bg(fs->super) && + (fs->super->s_first_meta_bg > fs->desc_blocks) && + !(flags & EXT2_FLAG_IGNORE_SB_ERRORS)) { + retval = EXT2_ET_CORRUPT_SUPERBLOCK; + goto cleanup; + } + if (flags & EXT2_FLAG_SUPER_ONLY) + goto skip_read_bg; + retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, + &fs->group_desc); + if (retval) + goto cleanup; + if (!group_block) + group_block = fs->super->s_first_data_block; + /* + * On a FS with a 1K blocksize, block 0 is reserved for bootloaders + * so we must increment block numbers to any group 0 items. + * + * However, we cannot touch group_block directly because in the meta_bg + * case, the ext2fs_descriptor_block_loc2() function will interpret + * group_block != s_first_data_block to mean that we want to access the + * backup group descriptors. This is not what we want if the caller + * set superblock == 0 (i.e. auto-detect the superblock), which is + * what's going on here. + */ + if (group_block == 0 && fs->blocksize == 1024) + group_zero_adjust = 1; + dest = (char *) fs->group_desc; +#ifdef WORDS_BIGENDIAN + groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); +#endif + if (ext2fs_has_feature_meta_bg(fs->super) && + !(flags & EXT2_FLAG_IMAGE_FILE)) { + first_meta_bg = fs->super->s_first_meta_bg; + if (first_meta_bg > fs->desc_blocks) + first_meta_bg = fs->desc_blocks; + } else + first_meta_bg = fs->desc_blocks; + if (first_meta_bg) { + retval = io_channel_read_blk(fs->io, group_block + + group_zero_adjust + 1, + first_meta_bg, dest); + if (retval) + goto cleanup; +#ifdef WORDS_BIGENDIAN + gdp = (struct ext2_group_desc *) dest; + for (j=0; j < groups_per_block*first_meta_bg; j++) { + gdp = ext2fs_group_desc(fs, fs->group_desc, j); + if (gdp) + ext2fs_swap_group_desc2(fs, gdp); + } +#endif + dest += fs->blocksize*first_meta_bg; + } + + for (i = first_meta_bg ; i < fs->desc_blocks; i++) { + blk = ext2fs_descriptor_block_loc2(fs, group_block, i); + io_channel_cache_readahead(fs->io, blk, 1); + } + + for (i=first_meta_bg ; i < fs->desc_blocks; i++) { + blk = ext2fs_descriptor_block_loc2(fs, group_block, i); + retval = io_channel_read_blk64(fs->io, blk, 1, dest); + if (retval) + goto cleanup; +#ifdef WORDS_BIGENDIAN + for (j=0; j < groups_per_block; j++) { + gdp = ext2fs_group_desc(fs, fs->group_desc, + i * groups_per_block + j); + if (gdp) + ext2fs_swap_group_desc2(fs, gdp); + } +#endif + dest += fs->blocksize; + } + + fs->stride = fs->super->s_raid_stride; + + /* + * If recovery is from backup superblock, Clear _UNININT flags & + * reset bg_itable_unused to zero + */ + if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) { + dgrp_t group; + + for (group = 0; group < fs->group_desc_count; group++) { + ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); + ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); + ext2fs_bg_itable_unused_set(fs, group, 0); + /* The checksum will be reset later, but fix it here + * anyway to avoid printing a lot of spurious errors. */ + ext2fs_group_desc_csum_set(fs, group); + } + if (fs->flags & EXT2_FLAG_RW) + ext2fs_mark_super_dirty(fs); + } +skip_read_bg: + if (ext2fs_has_feature_mmp(fs->super) && + !(flags & EXT2_FLAG_SKIP_MMP) && + (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) { + retval = ext2fs_mmp_start(fs); + if (retval) { + fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */ + ext2fs_mmp_stop(fs); + goto cleanup; + } + } + + if (fs->flags & EXT2_FLAG_SHARE_DUP) { + fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash, + block_sha_map_free_entry, 4096); + if (!fs->block_sha_map) { + retval = EXT2_ET_NO_MEMORY; + goto cleanup; + } + ext2fs_set_feature_shared_blocks(fs->super); + } + + if (ext2fs_has_feature_casefold(fs->super)) + fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding); + + fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; + *ret_fs = fs; + + return 0; +cleanup: + if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) { + ext2fs_free(fs); + fs = NULL; + } + *ret_fs = fs; + return retval; +} + +/* + * Set/get the filesystem data I/O channel. + * + * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. + */ +errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) +{ + if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) + return EXT2_ET_NOT_IMAGE_FILE; + if (old_io) { + *old_io = (fs->image_io == fs->io) ? 0 : fs->io; + } + return 0; +} + +errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) +{ + if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) + return EXT2_ET_NOT_IMAGE_FILE; + fs->io = new_io ? new_io : fs->image_io; + return 0; +} + +errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) +{ + errcode_t err; + + if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) + return EXT2_ET_NOT_IMAGE_FILE; + err = io_channel_set_blksize(new_io, fs->blocksize); + if (err) + return err; + if ((new_io == fs->image_io) || (new_io == fs->io)) + return 0; + if ((fs->image_io != fs->io) && + fs->image_io) + io_channel_close(fs->image_io); + if (fs->io) + io_channel_close(fs->io); + fs->io = fs->image_io = new_io; + fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | + EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; + fs->flags &= ~EXT2_FLAG_IMAGE_FILE; + return 0; +} |