/* * Read a squashfs filesystem. This is a highly compressed read only filesystem. * * Copyright (c) 2002, 2003, 2004, 2005, 2006 * Phillip Lougher * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * read_fs.c */ extern void read_bytes(int, long long, int, char *); extern int add_file(long long, long long, unsigned int *, int, unsigned int, int, int); #define TRUE 1 #define FALSE 0 #include #include #include #include #include #include #include #include #ifndef linux #define __BYTE_ORDER BYTE_ORDER #define __BIG_ENDIAN BIG_ENDIAN #define __LITTLE_ENDIAN LITTLE_ENDIAN #else #include #endif #include #include "read_fs.h" #include "global.h" #include #ifdef SQUASHFS_TRACE #define TRACE(s, args...) do { \ printf("mksquashfs: "s, ## args); \ } while(0) #else #define TRACE(s, args...) #endif #define ERROR(s, args...) do { \ fprintf(stderr, s, ## args); \ } while(0) static int swap; int read_block(int fd, long long start, long long *next, unsigned char *block, squashfs_super_block *sBlk) { unsigned short c_byte; int offset = 2; if(swap) { read_bytes(fd, start, 2, (char *) block); ((unsigned char *) &c_byte)[1] = block[0]; ((unsigned char *) &c_byte)[0] = block[1]; } else read_bytes(fd, start, 2, (char *)&c_byte); if(SQUASHFS_CHECK_DATA(sBlk->flags)) offset = 3; if(SQUASHFS_COMPRESSED(c_byte)) { char buffer[SQUASHFS_METADATA_SIZE]; int res; unsigned long bytes = SQUASHFS_METADATA_SIZE; c_byte = SQUASHFS_COMPRESSED_SIZE(c_byte); read_bytes(fd, start + offset, c_byte, buffer); if((res = uncompress(block, &bytes, (const unsigned char *) buffer, c_byte)) != Z_OK) { if(res == Z_MEM_ERROR) ERROR("zlib::uncompress failed, not enough memory\n"); else if(res == Z_BUF_ERROR) ERROR("zlib::uncompress failed, not enough room in output buffer\n"); else ERROR("zlib::uncompress failed, unknown error %d\n", res); return 0; } if(next) *next = start + offset + c_byte; return bytes; } else { c_byte = SQUASHFS_COMPRESSED_SIZE(c_byte); read_bytes(fd, start + offset, c_byte, (char *) block); if(next) *next = start + offset + c_byte; return c_byte; } } int scan_inode_table(int fd, long long start, long long end, long long root_inode_start, int root_inode_offset, squashfs_super_block *sBlk, squashfs_inode_header *dir_inode, unsigned char **inode_table, unsigned int *root_inode_block, unsigned int *root_inode_size, long long *uncompressed_file, unsigned int *uncompressed_directory, int *file_count, int *sym_count, int *dev_count, int *dir_count, int *fifo_count, int *sock_count) { unsigned char *cur_ptr; int byte, bytes = 0, size = 0, files = 0; squashfs_reg_inode_header inode; unsigned int directory_start_block; TRACE("scan_inode_table: start 0x%llx, end 0x%llx, root_inode_start 0x%llx\n", start, end, root_inode_start); while(start < end) { if(start == root_inode_start) { TRACE("scan_inode_table: read compressed block 0x%llx containing root inode\n", start); *root_inode_block = bytes; } if((size - bytes < SQUASHFS_METADATA_SIZE) && ((*inode_table = realloc(*inode_table, size += SQUASHFS_METADATA_SIZE)) == NULL)) return FALSE; TRACE("scan_inode_table: reading block 0x%llx\n", start); if((byte = read_block(fd, start, &start, *inode_table + bytes, sBlk)) == 0) { free(*inode_table); return FALSE; } bytes += byte; } /* * Read last inode entry which is the root directory inode, and obtain the last * directory start block index. This is used when calculating the total uncompressed * directory size. The directory bytes in the last block will be counted as normal. * * The root inode is ignored in the inode scan. This ensures there is * always enough bytes left to read a regular file inode entry */ *root_inode_size = bytes - (*root_inode_block + root_inode_offset); bytes = *root_inode_block + root_inode_offset; if(swap) { squashfs_base_inode_header sinode; memcpy(&sinode, *inode_table + bytes, sizeof(dir_inode->base)); SQUASHFS_SWAP_BASE_INODE_HEADER(&dir_inode->base, &sinode, sizeof(squashfs_base_inode_header)); } else memcpy(&dir_inode->base, *inode_table + bytes, sizeof(dir_inode->base)); if(dir_inode->base.inode_type == SQUASHFS_DIR_TYPE) { if(swap) { squashfs_dir_inode_header sinode; memcpy(&sinode, *inode_table + bytes, sizeof(dir_inode->dir)); SQUASHFS_SWAP_DIR_INODE_HEADER(&dir_inode->dir, &sinode); } else memcpy(&dir_inode->dir, *inode_table + bytes, sizeof(dir_inode->dir)); directory_start_block = dir_inode->dir.start_block; } else { if(swap) { squashfs_ldir_inode_header sinode; memcpy(&sinode, *inode_table + bytes, sizeof(dir_inode->ldir)); SQUASHFS_SWAP_LDIR_INODE_HEADER(&dir_inode->ldir, &sinode); } else memcpy(&dir_inode->ldir, *inode_table + bytes, sizeof(dir_inode->ldir)); directory_start_block = dir_inode->ldir.start_block; } for(cur_ptr = *inode_table; cur_ptr < *inode_table + bytes; files ++) { if(swap) { squashfs_reg_inode_header sinode; memcpy(&sinode, cur_ptr, sizeof(inode)); SQUASHFS_SWAP_REG_INODE_HEADER(&inode, &sinode); } else memcpy(&inode, cur_ptr, sizeof(inode)); TRACE("scan_inode_table: processing inode @ byte position 0x%x, type 0x%x\n", cur_ptr - *inode_table, inode.inode_type); switch(inode.inode_type) { case SQUASHFS_FILE_TYPE: { int frag_bytes = inode.fragment == SQUASHFS_INVALID_FRAG ? 0 : inode.file_size % sBlk->block_size; int blocks = inode.fragment == SQUASHFS_INVALID_FRAG ? (inode.file_size + sBlk->block_size - 1) >> sBlk->block_log : inode.file_size >> sBlk->block_log; long long file_bytes = 0; int i, start = inode.start_block; unsigned int *block_list; TRACE("scan_inode_table: regular file, file_size %lld, blocks %d\n", inode.file_size, blocks); if((block_list = malloc(blocks * sizeof(unsigned int))) == NULL) { ERROR("Out of memory in block list malloc\n"); goto failed; } cur_ptr += sizeof(inode); if(swap) { unsigned int sblock_list[blocks]; memcpy(sblock_list, cur_ptr, blocks * sizeof(unsigned int)); SQUASHFS_SWAP_INTS(block_list, sblock_list, blocks); } else memcpy(block_list, cur_ptr, blocks * sizeof(unsigned int)); *uncompressed_file += inode.file_size; (*file_count) ++; for(i = 0; i < blocks; i++) file_bytes += SQUASHFS_COMPRESSED_SIZE_BLOCK(block_list[i]); add_file(start, file_bytes, block_list, blocks, inode.fragment, inode.offset, frag_bytes); cur_ptr += blocks * sizeof(unsigned int); break; } case SQUASHFS_LREG_TYPE: { squashfs_lreg_inode_header inode; int frag_bytes; int blocks; long long file_bytes = 0; int i, start; unsigned int *block_list; if(swap) { squashfs_lreg_inode_header sinodep; memcpy(&sinodep, cur_ptr, sizeof(sinodep)); SQUASHFS_SWAP_LREG_INODE_HEADER(&inode, &sinodep); } else memcpy(&inode, cur_ptr, sizeof(inode)); TRACE("scan_inode_table: extended regular file, file_size %lld, blocks %d\n", inode.file_size, blocks); cur_ptr += sizeof(inode); frag_bytes = inode.fragment == SQUASHFS_INVALID_FRAG ? 0 : inode.file_size % sBlk->block_size; blocks = inode.fragment == SQUASHFS_INVALID_FRAG ? (inode.file_size + sBlk->block_size - 1) >> sBlk->block_log : inode.file_size >> sBlk->block_log; start = inode.start_block; if((block_list = malloc(blocks * sizeof(unsigned int))) == NULL) { ERROR("Out of memory in block list malloc\n"); goto failed; } if(swap) { unsigned int sblock_list[blocks]; memcpy(sblock_list, cur_ptr, blocks * sizeof(unsigned int)); SQUASHFS_SWAP_INTS(block_list, sblock_list, blocks); } else memcpy(block_list, cur_ptr, blocks * sizeof(unsigned int)); *uncompressed_file += inode.file_size; (*file_count) ++; for(i = 0; i < blocks; i++) file_bytes += SQUASHFS_COMPRESSED_SIZE_BLOCK(block_list[i]); add_file(start, file_bytes, block_list, blocks, inode.fragment, inode.offset, frag_bytes); cur_ptr += blocks * sizeof(unsigned int); break; } case SQUASHFS_SYMLINK_TYPE: { squashfs_symlink_inode_header inodep; if(swap) { squashfs_symlink_inode_header sinodep; memcpy(&sinodep, cur_ptr, sizeof(sinodep)); SQUASHFS_SWAP_SYMLINK_INODE_HEADER(&inodep, &sinodep); } else memcpy(&inodep, cur_ptr, sizeof(inodep)); (*sym_count) ++; cur_ptr += sizeof(inodep) + inodep.symlink_size; break; } case SQUASHFS_DIR_TYPE: { squashfs_dir_inode_header dir_inode; if(swap) { squashfs_dir_inode_header sinode; memcpy(&sinode, cur_ptr, sizeof(dir_inode)); SQUASHFS_SWAP_DIR_INODE_HEADER(&dir_inode, &sinode); } else memcpy(&dir_inode, cur_ptr, sizeof(dir_inode)); if(dir_inode.start_block < directory_start_block) *uncompressed_directory += dir_inode.file_size; (*dir_count) ++; cur_ptr += sizeof(squashfs_dir_inode_header); break; } case SQUASHFS_LDIR_TYPE: { squashfs_ldir_inode_header dir_inode; int i; if(swap) { squashfs_ldir_inode_header sinode; memcpy(&sinode, cur_ptr, sizeof(dir_inode)); SQUASHFS_SWAP_LDIR_INODE_HEADER(&dir_inode, &sinode); } else memcpy(&dir_inode, cur_ptr, sizeof(dir_inode)); if(dir_inode.start_block < directory_start_block) *uncompressed_directory += dir_inode.file_size; (*dir_count) ++; cur_ptr += sizeof(squashfs_ldir_inode_header); for(i = 0; i < dir_inode.i_count; i++) { squashfs_dir_index index; if(swap) { squashfs_dir_index sindex; memcpy(&sindex, cur_ptr, sizeof(squashfs_dir_index)); SQUASHFS_SWAP_DIR_INDEX(&index, &sindex); } else memcpy(&index, cur_ptr, sizeof(squashfs_dir_index)); cur_ptr += sizeof(squashfs_dir_index) + index.size + 1; } break; } case SQUASHFS_BLKDEV_TYPE: case SQUASHFS_CHRDEV_TYPE: (*dev_count) ++; cur_ptr += sizeof(squashfs_dev_inode_header); break; case SQUASHFS_FIFO_TYPE: (*fifo_count) ++; cur_ptr += sizeof(squashfs_ipc_inode_header); break; case SQUASHFS_SOCKET_TYPE: (*sock_count) ++; cur_ptr += sizeof(squashfs_ipc_inode_header); break; default: ERROR("Unknown inode type %d in scan_inode_table!\n", inode.inode_type); goto failed; } } return files; failed: free(*inode_table); return FALSE; } int read_super(int fd, squashfs_super_block *sBlk, int *be, char *source) { read_bytes(fd, SQUASHFS_START, sizeof(squashfs_super_block), (char *) sBlk); /* Check it is a SQUASHFS superblock */ swap = 0; if(sBlk->s_magic != SQUASHFS_MAGIC) { if(sBlk->s_magic == SQUASHFS_MAGIC_SWAP) { squashfs_super_block sblk; ERROR("Reading a different endian SQUASHFS filesystem on %s - ignoring -le/-be options\n", source); SQUASHFS_SWAP_SUPER_BLOCK(&sblk, sBlk); memcpy(sBlk, &sblk, sizeof(squashfs_super_block)); swap = 1; } else { ERROR("Can't find a SQUASHFS superblock on %s\n", source); goto failed_mount; } } /* Check the MAJOR & MINOR versions */ if(sBlk->s_major != SQUASHFS_MAJOR || sBlk->s_minor > SQUASHFS_MINOR) { if(sBlk->s_major < 3) ERROR("Filesystem on %s is a SQUASHFS %d.%d filesystem. Appending\nto SQUASHFS %d.%d filesystems is not supported. Please convert it to a SQUASHFS 3.0 filesystem\n", source, sBlk->s_major, sBlk->s_minor, sBlk->s_major, sBlk->s_minor); else ERROR("Major/Minor mismatch, filesystem on %s is %d.%d, I support 3.0\n", source, sBlk->s_major, sBlk->s_minor); goto failed_mount; } #if __BYTE_ORDER == __BIG_ENDIAN *be = !swap; #else *be = swap; #endif printf("Found a valid SQUASHFS superblock on %s.\n", source); printf("\tInodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(sBlk->flags) ? "un" : ""); printf("\tData is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(sBlk->flags) ? "un" : ""); printf("\tFragments are %scompressed\n", SQUASHFS_UNCOMPRESSED_FRAGMENTS(sBlk->flags) ? "un" : ""); printf("\tCheck data is %s present in the filesystem\n", SQUASHFS_CHECK_DATA(sBlk->flags) ? "" : "not"); printf("\tFragments are %s present in the filesystem\n", SQUASHFS_NO_FRAGMENTS(sBlk->flags) ? "not" : ""); printf("\tAlways_use_fragments option is %s specified\n", SQUASHFS_ALWAYS_FRAGMENTS(sBlk->flags) ? "" : "not"); printf("\tDuplicates are %s removed\n", SQUASHFS_DUPLICATES(sBlk->flags) ? "" : "not"); printf("\tFilesystem size %.2f Kbytes (%.2f Mbytes)\n", sBlk->bytes_used / 1024.0, sBlk->bytes_used / (1024.0 * 1024.0)); printf("\tBlock size %d\n", sBlk->block_size); printf("\tNumber of fragments %d\n", sBlk->fragments); printf("\tNumber of inodes %d\n", sBlk->inodes); printf("\tNumber of uids %d\n", sBlk->no_uids); printf("\tNumber of gids %d\n", sBlk->no_guids); TRACE("sBlk->inode_table_start %llx\n", sBlk->inode_table_start); TRACE("sBlk->directory_table_start %llx\n", sBlk->directory_table_start); TRACE("sBlk->uid_start %llx\n", sBlk->uid_start); TRACE("sBlk->fragment_table_start %llx\n", sBlk->fragment_table_start); printf("\n"); return TRUE; failed_mount: return FALSE; } unsigned char *squashfs_readdir(int fd, int root_entries, unsigned int directory_start_block, int offset, int size, unsigned int *last_directory_block, squashfs_super_block *sBlk, void (push_directory_entry)(char *, squashfs_inode, int, int)) { squashfs_dir_header dirh; char buffer[sizeof(squashfs_dir_entry) + SQUASHFS_NAME_LEN + 1]; squashfs_dir_entry *dire = (squashfs_dir_entry *) buffer; unsigned char *directory_table = NULL; int byte, bytes = 0, dir_count; long long start = sBlk->directory_table_start + directory_start_block, last_start_block; size += offset; if((directory_table = malloc((size + SQUASHFS_METADATA_SIZE * 2 - 1) & ~(SQUASHFS_METADATA_SIZE - 1))) == NULL) return NULL; while(bytes < size) { TRACE("squashfs_readdir: reading block 0x%llx, bytes read so far %d\n", start, bytes); last_start_block = start; if((byte = read_block(fd, start, &start, directory_table + bytes, sBlk)) == 0) { free(directory_table); return NULL; } bytes += byte; } if(!root_entries) goto all_done; bytes = offset; while(bytes < size) { if(swap) { squashfs_dir_header sdirh; memcpy(&sdirh, directory_table + bytes, sizeof(sdirh)); SQUASHFS_SWAP_DIR_HEADER(&dirh, &sdirh); } else memcpy(&dirh, directory_table + bytes, sizeof(dirh)); dir_count = dirh.count + 1; TRACE("squashfs_readdir: Read directory header @ byte position 0x%x, 0x%x directory entries\n", bytes, dir_count); bytes += sizeof(dirh); while(dir_count--) { if(swap) { squashfs_dir_entry sdire; memcpy(&sdire, directory_table + bytes, sizeof(sdire)); SQUASHFS_SWAP_DIR_ENTRY(dire, &sdire); } else memcpy(dire, directory_table + bytes, sizeof(dire)); bytes += sizeof(*dire); memcpy(dire->name, directory_table + bytes, dire->size + 1); dire->name[dire->size + 1] = '\0'; TRACE("squashfs_readdir: pushing directory entry %s, inode %x:%x, type 0x%x\n", dire->name, dirh.start_block, dire->offset, dire->type); push_directory_entry(dire->name, SQUASHFS_MKINODE(dirh.start_block, dire->offset), dire->inode_number, dire->type); bytes += dire->size + 1; } } all_done: *last_directory_block = (unsigned int) last_start_block - sBlk->directory_table_start; return directory_table; } int read_fragment_table(int fd, squashfs_super_block *sBlk, squashfs_fragment_entry **fragment_table) { int i, indexes = SQUASHFS_FRAGMENT_INDEXES(sBlk->fragments); squashfs_fragment_index fragment_table_index[indexes]; TRACE("read_fragment_table: %d fragments, reading %d fragment indexes from 0x%llx\n", sBlk->fragments, indexes, sBlk->fragment_table_start); if(sBlk->fragments == 0) return 1; if((*fragment_table = (squashfs_fragment_entry *) malloc(sBlk->fragments * sizeof(squashfs_fragment_entry))) == NULL) { ERROR("Failed to allocate fragment table\n"); return 0; } if(swap) { squashfs_fragment_index sfragment_table_index[indexes]; read_bytes(fd, sBlk->fragment_table_start, SQUASHFS_FRAGMENT_INDEX_BYTES(sBlk->fragments), (char *) sfragment_table_index); SQUASHFS_SWAP_FRAGMENT_INDEXES(fragment_table_index, sfragment_table_index, indexes); } else read_bytes(fd, sBlk->fragment_table_start, SQUASHFS_FRAGMENT_INDEX_BYTES(sBlk->fragments), (char *) fragment_table_index); for(i = 0; i < indexes; i++) { int length = read_block(fd, fragment_table_index[i], NULL, ((unsigned char *) *fragment_table) + (i * SQUASHFS_METADATA_SIZE), sBlk); TRACE("Read fragment table block %d, from 0x%llx, length %d\n", i, fragment_table_index[i], length); } if(swap) { squashfs_fragment_entry sfragment; for(i = 0; i < sBlk->fragments; i++) { SQUASHFS_SWAP_FRAGMENT_ENTRY((&sfragment), (&(*fragment_table)[i])); memcpy((char *) &(*fragment_table)[i], (char *) &sfragment, sizeof(squashfs_fragment_entry)); } } return 1; } long long read_filesystem(char *root_name, int fd, squashfs_super_block *sBlk, char **cinode_table, char **data_cache, char **cdirectory_table, char **directory_data_cache, unsigned int *last_directory_block, unsigned int *inode_dir_offset, unsigned int *inode_dir_file_size, unsigned int *root_inode_size, unsigned int *inode_dir_start_block, int *file_count, int *sym_count, int *dev_count, int *dir_count, int *fifo_count, int *sock_count, squashfs_uid *uids, unsigned short *uid_count, squashfs_uid *guids, unsigned short *guid_count, long long *uncompressed_file, unsigned int *uncompressed_inode, unsigned int *uncompressed_directory, unsigned int *inode_dir_inode_number, unsigned int *inode_dir_parent_inode, void (push_directory_entry)(char *, squashfs_inode, int, int), squashfs_fragment_entry **fragment_table) { unsigned char *inode_table = NULL, *directory_table; long long start = sBlk->inode_table_start, end = sBlk->directory_table_start, root_inode_start = start + SQUASHFS_INODE_BLK(sBlk->root_inode); unsigned int root_inode_offset = SQUASHFS_INODE_OFFSET(sBlk->root_inode), root_inode_block, files; squashfs_inode_header inode; printf("Scanning existing filesystem...\n"); if(read_fragment_table(fd, sBlk, fragment_table) == 0) goto error; if((files = scan_inode_table(fd, start, end, root_inode_start, root_inode_offset, sBlk, &inode, &inode_table, &root_inode_block, root_inode_size, uncompressed_file, uncompressed_directory, file_count, sym_count, dev_count, dir_count, fifo_count, sock_count)) == 0) { ERROR("read_filesystem: inode table read failed\n"); goto error; } *uncompressed_inode = root_inode_block; printf("Read existing filesystem, %d inodes scanned\n", files); if(inode.base.inode_type == SQUASHFS_DIR_TYPE || inode.base.inode_type == SQUASHFS_LDIR_TYPE) { if(inode.base.inode_type == SQUASHFS_DIR_TYPE) { *inode_dir_start_block = inode.dir.start_block; *inode_dir_offset = inode.dir.offset; *inode_dir_file_size = inode.dir.file_size - 3; *inode_dir_inode_number = inode.dir.inode_number; *inode_dir_parent_inode = inode.dir.parent_inode; } else { *inode_dir_start_block = inode.ldir.start_block; *inode_dir_offset = inode.ldir.offset; *inode_dir_file_size = inode.ldir.file_size - 3; *inode_dir_inode_number = inode.ldir.inode_number; *inode_dir_parent_inode = inode.ldir.parent_inode; } if((directory_table = squashfs_readdir(fd, !root_name, *inode_dir_start_block, *inode_dir_offset, *inode_dir_file_size, last_directory_block, sBlk, push_directory_entry)) == NULL) { ERROR("read_filesystem: Could not read root directory\n"); goto error; } root_inode_start -= start; if((*cinode_table = (char *) malloc(root_inode_start)) == NULL) { ERROR("read_filesystem: failed to alloc space for existing filesystem inode table\n"); goto error; } read_bytes(fd, start, root_inode_start, *cinode_table); if((*cdirectory_table = (char *) malloc(*last_directory_block)) == NULL) { ERROR("read_filesystem: failed to alloc space for existing filesystem directory table\n"); goto error; } read_bytes(fd, sBlk->directory_table_start, *last_directory_block, *cdirectory_table); if((*data_cache = (char *) malloc(root_inode_offset + *root_inode_size)) == NULL) { ERROR("read_filesystem: failed to alloc inode cache\n"); goto error; } memcpy(*data_cache, inode_table + root_inode_block, root_inode_offset + *root_inode_size); if((*directory_data_cache = (char *) malloc(*inode_dir_offset + *inode_dir_file_size)) == NULL) { ERROR("read_filesystem: failed to alloc directory cache\n"); goto error; } memcpy(*directory_data_cache, directory_table, *inode_dir_offset + *inode_dir_file_size); if(!swap) read_bytes(fd, sBlk->uid_start, sBlk->no_uids * sizeof(squashfs_uid), (char *) uids); else { squashfs_uid uids_copy[sBlk->no_uids]; read_bytes(fd, sBlk->uid_start, sBlk->no_uids * sizeof(squashfs_uid), (char *) uids_copy); SQUASHFS_SWAP_DATA(uids, uids_copy, sBlk->no_uids, sizeof(squashfs_uid) * 8); } if(!swap) read_bytes(fd, sBlk->guid_start, sBlk->no_guids * sizeof(squashfs_uid), (char *) guids); else { squashfs_uid guids_copy[sBlk->no_guids]; read_bytes(fd, sBlk->guid_start, sBlk->no_guids * sizeof(squashfs_uid), (char *) guids_copy); SQUASHFS_SWAP_DATA(guids, guids_copy, sBlk->no_guids, sizeof(squashfs_uid) * 8); } *uid_count = sBlk->no_uids; *guid_count = sBlk->no_guids; free(inode_table); free(directory_table); return sBlk->inode_table_start; } error: return 0; }