| /* |
| * inode.c --- utility routines to read and write inodes |
| * |
| * Copyright (C) 1993, 1994, 1995, 1996, 1997 Theodore Ts'o. |
| * |
| * %Begin-Header% |
| * This file may be redistributed under the terms of the GNU Public |
| * License. |
| * %End-Header% |
| */ |
| |
| #include <stdio.h> |
| #include <string.h> |
| #if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| #include <stdlib.h> |
| #if HAVE_SYS_STAT_H |
| #include <sys/stat.h> |
| #endif |
| #if HAVE_SYS_TYPES_H |
| #include <sys/types.h> |
| #endif |
| |
| #include <linux/ext2_fs.h> |
| |
| #include "ext2fsP.h" |
| |
| struct ext2_struct_inode_scan { |
| errcode_t magic; |
| ext2_filsys fs; |
| ino_t current_inode; |
| blk_t current_block; |
| dgrp_t current_group; |
| ino_t inodes_left; |
| blk_t blocks_left; |
| dgrp_t groups_left; |
| blk_t inode_buffer_blocks; |
| char * inode_buffer; |
| int inode_size; |
| char * ptr; |
| int bytes_left; |
| char *temp_buffer; |
| errcode_t (*done_group)(ext2_filsys fs, |
| ext2_inode_scan scan, |
| dgrp_t group, |
| void * private); |
| void * done_group_data; |
| int bad_block_ptr; |
| int scan_flags; |
| int reserved[6]; |
| }; |
| |
| static errcode_t create_icache(ext2_filsys fs) |
| { |
| int i; |
| |
| if (fs->icache) |
| return 0; |
| fs->icache = malloc(sizeof(struct ext2_inode_cache)); |
| memset(fs->icache, 0, sizeof(struct ext2_inode_cache)); |
| fs->icache->buffer = malloc(fs->blocksize); |
| if (!fs->icache->buffer) { |
| free(fs->icache); |
| return EXT2_NO_MEMORY; |
| } |
| fs->icache->buffer_blk = 0; |
| fs->icache->cache_last = -1; |
| fs->icache->cache_size = 4; |
| fs->icache->refcount = 1; |
| fs->icache->cache = malloc(sizeof(struct ext2_inode_cache_ent) |
| * fs->icache->cache_size); |
| if (!fs->icache->cache) { |
| free(fs->icache->buffer); |
| free(fs->icache); |
| return EXT2_NO_MEMORY; |
| } |
| for (i=0; i < fs->icache->cache_size; i++) |
| fs->icache->cache[i].ino = 0; |
| return 0; |
| } |
| |
| errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks, |
| ext2_inode_scan *ret_scan) |
| { |
| ext2_inode_scan scan; |
| errcode_t retval; |
| errcode_t (*save_get_blocks)(ext2_filsys f, ino_t ino, blk_t *blocks); |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| /* |
| * If fs->badblocks isn't set, then set it --- since the inode |
| * scanning functions require it. |
| */ |
| if (fs->badblocks == 0) { |
| /* |
| * Temporarly save fs->get_blocks and set it to zero, |
| * for compatibility with old e2fsck's. |
| */ |
| save_get_blocks = fs->get_blocks; |
| fs->get_blocks = 0; |
| retval = ext2fs_read_bb_inode(fs, &fs->badblocks); |
| if (retval && fs->badblocks) { |
| badblocks_list_free(fs->badblocks); |
| fs->badblocks = 0; |
| } |
| fs->get_blocks = save_get_blocks; |
| } |
| |
| scan = (ext2_inode_scan) malloc(sizeof(struct ext2_struct_inode_scan)); |
| if (!scan) |
| return EXT2_NO_MEMORY; |
| memset(scan, 0, sizeof(struct ext2_struct_inode_scan)); |
| |
| scan->magic = EXT2_ET_MAGIC_INODE_SCAN; |
| scan->fs = fs; |
| scan->inode_size = EXT2_INODE_SIZE(fs->super); |
| scan->bytes_left = 0; |
| scan->current_group = -1; |
| scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8; |
| scan->groups_left = fs->group_desc_count; |
| scan->inode_buffer = malloc((size_t) (scan->inode_buffer_blocks * |
| fs->blocksize)); |
| scan->done_group = 0; |
| scan->done_group_data = 0; |
| scan->bad_block_ptr = 0; |
| if (!scan->inode_buffer) { |
| free(scan); |
| return EXT2_NO_MEMORY; |
| } |
| scan->temp_buffer = malloc(scan->inode_size); |
| if (!scan->temp_buffer) { |
| free(scan->inode_buffer); |
| free(scan); |
| return EXT2_NO_MEMORY; |
| } |
| if (scan->fs->badblocks && scan->fs->badblocks->num) |
| scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS; |
| *ret_scan = scan; |
| return 0; |
| } |
| |
| void ext2fs_close_inode_scan(ext2_inode_scan scan) |
| { |
| if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN)) |
| return; |
| |
| free(scan->inode_buffer); |
| scan->inode_buffer = NULL; |
| free(scan->temp_buffer); |
| scan->temp_buffer = NULL; |
| free(scan); |
| return; |
| } |
| |
| void ext2fs_set_inode_callback(ext2_inode_scan scan, |
| errcode_t (*done_group)(ext2_filsys fs, |
| ext2_inode_scan scan, |
| dgrp_t group, |
| void * private), |
| void *done_group_data) |
| { |
| if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN)) |
| return; |
| |
| scan->done_group = done_group; |
| scan->done_group_data = done_group_data; |
| } |
| |
| int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags, |
| int clear_flags) |
| { |
| int old_flags; |
| |
| if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN)) |
| return 0; |
| |
| old_flags = scan->scan_flags; |
| scan->scan_flags &= ~clear_flags; |
| scan->scan_flags |= set_flags; |
| return old_flags; |
| } |
| |
| /* |
| * This function is called by ext2fs_get_next_inode when it needs to |
| * get ready to read in a new blockgroup. |
| */ |
| static errcode_t get_next_blockgroup(ext2_inode_scan scan) |
| { |
| scan->current_group++; |
| scan->groups_left--; |
| |
| scan->current_block = scan->fs-> |
| group_desc[scan->current_group].bg_inode_table; |
| |
| scan->bytes_left = 0; |
| scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super); |
| scan->blocks_left = scan->fs->inode_blocks_per_group; |
| return 0; |
| } |
| |
| errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan, |
| int group) |
| { |
| scan->current_group = group - 1; |
| scan->groups_left = scan->fs->group_desc_count - group; |
| scan->current_inode = group * EXT2_INODES_PER_GROUP(scan->fs->super); |
| return get_next_blockgroup(scan); |
| } |
| |
| /* |
| * This function is called by get_next_blocks() to check for bad |
| * blocks in the inode table. |
| * |
| * This function assumes that badblocks_list->list is sorted in |
| * increasing order. |
| */ |
| static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan, |
| blk_t *num_blocks) |
| { |
| blk_t blk = scan->current_block; |
| badblocks_list bb = scan->fs->badblocks; |
| |
| /* |
| * If the inode table is missing, then obviously there are no |
| * bad blocks. :-) |
| */ |
| if (blk == 0) |
| return 0; |
| |
| /* |
| * If the current block is greater than the bad block listed |
| * in the bad block list, then advance the pointer until this |
| * is no longer the case. If we run out of bad blocks, then |
| * we don't need to do any more checking! |
| */ |
| while (blk > bb->list[scan->bad_block_ptr]) { |
| if (++scan->bad_block_ptr >= bb->num) { |
| scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS; |
| return 0; |
| } |
| } |
| |
| /* |
| * If the current block is equal to the bad block listed in |
| * the bad block list, then handle that one block specially. |
| * (We could try to handle runs of bad blocks, but that |
| * only increases CPU efficiency by a small amount, at the |
| * expense of a huge expense of code complexity, and for an |
| * uncommon case at that.) |
| */ |
| if (blk == bb->list[scan->bad_block_ptr]) { |
| scan->scan_flags |= EXT2_SF_BAD_INODE_BLK; |
| *num_blocks = 1; |
| if (++scan->bad_block_ptr >= bb->num) |
| scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS; |
| return 0; |
| } |
| |
| /* |
| * If there is a bad block in the range that we're about to |
| * read in, adjust the number of blocks to read so that we we |
| * don't read in the bad block. (Then the next block to read |
| * will be the bad block, which is handled in the above case.) |
| */ |
| if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr]) |
| *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk); |
| |
| return 0; |
| } |
| |
| /* |
| * This function is called by ext2fs_get_next_inode when it needs to |
| * read in more blocks from the current blockgroup's inode table. |
| */ |
| static errcode_t get_next_blocks(ext2_inode_scan scan) |
| { |
| blk_t num_blocks; |
| errcode_t retval; |
| |
| /* |
| * Figure out how many blocks to read; we read at most |
| * inode_buffer_blocks, and perhaps less if there aren't that |
| * many blocks left to read. |
| */ |
| num_blocks = scan->inode_buffer_blocks; |
| if (num_blocks > scan->blocks_left) |
| num_blocks = scan->blocks_left; |
| |
| /* |
| * If the past block "read" was a bad block, then mark the |
| * left-over extra bytes as also being bad. |
| */ |
| if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) { |
| if (scan->bytes_left) |
| scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES; |
| scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK; |
| } |
| |
| /* |
| * Do inode bad block processing, if necessary. |
| */ |
| if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) { |
| retval = check_for_inode_bad_blocks(scan, &num_blocks); |
| if (retval) |
| return retval; |
| } |
| |
| if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) || |
| (scan->current_block == 0)) { |
| memset(scan->inode_buffer, 0, |
| (size_t) num_blocks * scan->fs->blocksize); |
| } else { |
| retval = io_channel_read_blk(scan->fs->io, |
| scan->current_block, |
| (int) num_blocks, |
| scan->inode_buffer); |
| if (retval) |
| return EXT2_ET_NEXT_INODE_READ; |
| } |
| scan->ptr = scan->inode_buffer; |
| scan->bytes_left = num_blocks * scan->fs->blocksize; |
| |
| scan->blocks_left -= num_blocks; |
| if (scan->current_block) |
| scan->current_block += num_blocks; |
| return 0; |
| } |
| |
| errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ino_t *ino, |
| struct ext2_inode *inode) |
| { |
| errcode_t retval; |
| int extra_bytes = 0; |
| |
| EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN); |
| |
| /* |
| * Do we need to start reading a new block group? |
| */ |
| if (scan->inodes_left <= 0) { |
| retry: |
| if (scan->done_group) { |
| retval = (scan->done_group) |
| (scan->fs, scan, scan->current_group, |
| scan->done_group_data); |
| if (retval) |
| return retval; |
| } |
| if (scan->groups_left <= 0) { |
| *ino = 0; |
| return 0; |
| } |
| retval = get_next_blockgroup(scan); |
| if (retval) |
| return retval; |
| if (scan->current_block == 0) { |
| if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) { |
| goto retry; |
| } else |
| return EXT2_ET_MISSING_INODE_TABLE; |
| } |
| } |
| |
| /* |
| * Have we run out of space in the inode buffer? If so, we |
| * need to read in more blocks. |
| */ |
| if (scan->bytes_left < scan->inode_size) { |
| memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left); |
| extra_bytes = scan->bytes_left; |
| |
| retval = get_next_blocks(scan); |
| if (retval) |
| return retval; |
| } |
| |
| retval = 0; |
| if (extra_bytes) { |
| memcpy(scan->temp_buffer+extra_bytes, scan->ptr, |
| scan->inode_size - extra_bytes); |
| scan->ptr += scan->inode_size - extra_bytes; |
| scan->bytes_left -= scan->inode_size - extra_bytes; |
| |
| if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) |
| ext2fs_swap_inode(scan->fs, inode, |
| (struct ext2_inode *) scan->temp_buffer, 0); |
| else |
| *inode = *((struct ext2_inode *) scan->temp_buffer); |
| if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES) |
| retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE; |
| scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES; |
| } else { |
| if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) |
| ext2fs_swap_inode(scan->fs, inode, |
| (struct ext2_inode *) scan->ptr, 0); |
| else |
| *inode = *((struct ext2_inode *) scan->ptr); |
| scan->ptr += scan->inode_size; |
| scan->bytes_left -= scan->inode_size; |
| if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) |
| retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE; |
| } |
| |
| scan->inodes_left--; |
| scan->current_inode++; |
| *ino = scan->current_inode; |
| return retval; |
| } |
| |
| /* |
| * Functions to read and write a single inode. |
| */ |
| errcode_t ext2fs_read_inode (ext2_filsys fs, ino_t ino, |
| struct ext2_inode * inode) |
| { |
| unsigned long group, block, block_nr, offset; |
| char *ptr; |
| errcode_t retval; |
| int clen, length, i; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| /* Check to see if user has an override function */ |
| if (fs->read_inode) { |
| retval = (fs->read_inode)(fs, ino, inode); |
| if (retval != EXT2_ET_CALLBACK_NOTHANDLED) |
| return retval; |
| } |
| /* Create inode cache if not present */ |
| if (!fs->icache) { |
| retval = create_icache(fs); |
| if (retval) |
| return retval; |
| } |
| /* Check to see if it's in the inode cache */ |
| for (i=0; i < fs->icache->cache_size; i++) { |
| if (fs->icache->cache[i].ino == ino) { |
| *inode = fs->icache->cache[i].inode; |
| return 0; |
| } |
| } |
| if (ino > fs->super->s_inodes_count) |
| return EXT2_ET_BAD_INODE_NUM; |
| group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super); |
| offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) * |
| EXT2_INODE_SIZE(fs->super); |
| block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super); |
| if (!fs->group_desc[(unsigned)group].bg_inode_table) |
| return EXT2_ET_MISSING_INODE_TABLE; |
| block_nr = fs->group_desc[(unsigned)group].bg_inode_table + block; |
| if (block_nr != fs->icache->buffer_blk) { |
| retval = io_channel_read_blk(fs->io, block_nr, 1, |
| fs->icache->buffer); |
| if (retval) |
| return retval; |
| fs->icache->buffer_blk = block_nr; |
| } |
| offset &= (EXT2_BLOCK_SIZE(fs->super) - 1); |
| ptr = ((char *) fs->icache->buffer) + (unsigned) offset; |
| |
| memset(inode, 0, sizeof(struct ext2_inode)); |
| length = EXT2_INODE_SIZE(fs->super); |
| if (length > sizeof(struct ext2_inode)) |
| length = sizeof(struct ext2_inode); |
| |
| if ((offset + length) > EXT2_BLOCK_SIZE(fs->super)) { |
| clen = (int) (EXT2_BLOCK_SIZE(fs->super) - offset); |
| memcpy((char *) inode, ptr, clen); |
| length -= clen; |
| |
| retval = io_channel_read_blk(fs->io, block_nr+1, 1, |
| fs->icache->buffer); |
| if (retval) { |
| fs->icache->buffer_blk = 0; |
| return retval; |
| } |
| fs->icache->buffer_blk = block_nr+1; |
| |
| memcpy(((char *) inode) + clen, |
| fs->icache->buffer, length); |
| } else |
| memcpy((char *) inode, ptr, length); |
| |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) |
| ext2fs_swap_inode(fs, inode, inode, 0); |
| |
| /* Update the inode cache */ |
| fs->icache->cache_last = (fs->icache->cache_last + 1) % |
| fs->icache->cache_size; |
| fs->icache->cache[fs->icache->cache_last].ino = ino; |
| fs->icache->cache[fs->icache->cache_last].inode = *inode; |
| |
| return 0; |
| } |
| |
| errcode_t ext2fs_write_inode(ext2_filsys fs, ino_t ino, |
| struct ext2_inode * inode) |
| { |
| unsigned long group, block, block_nr, offset; |
| errcode_t retval; |
| struct ext2_inode temp_inode; |
| char *ptr; |
| int clen, length, i; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| /* Check to see if user provided an override function */ |
| if (fs->write_inode) { |
| retval = (fs->write_inode)(fs, ino, inode); |
| if (retval != EXT2_ET_CALLBACK_NOTHANDLED) |
| return retval; |
| } |
| |
| /* Check to see if the inode cache needs to be updated */ |
| if (fs->icache) { |
| for (i=0; i < fs->icache->cache_size; i++) { |
| if (fs->icache->cache[i].ino == ino) { |
| fs->icache->cache[i].inode = *inode; |
| break; |
| } |
| } |
| } else { |
| retval = create_icache(fs); |
| if (retval) |
| return retval; |
| } |
| |
| if (!(fs->flags & EXT2_FLAG_RW)) |
| return EXT2_ET_RO_FILSYS; |
| |
| if (ino > fs->super->s_inodes_count) |
| return EXT2_ET_BAD_INODE_NUM; |
| |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) |
| ext2fs_swap_inode(fs, &temp_inode, inode, 1); |
| else |
| memcpy(&temp_inode, inode, sizeof(struct ext2_inode)); |
| |
| group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super); |
| offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) * |
| EXT2_INODE_SIZE(fs->super); |
| block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super); |
| if (!fs->group_desc[(unsigned) group].bg_inode_table) |
| return EXT2_ET_MISSING_INODE_TABLE; |
| block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block; |
| offset &= (EXT2_BLOCK_SIZE(fs->super) - 1); |
| ptr = (char *) fs->icache->buffer + (unsigned) offset; |
| |
| length = EXT2_INODE_SIZE(fs->super); |
| clen = length; |
| if (length > sizeof(struct ext2_inode)) |
| length = sizeof(struct ext2_inode); |
| |
| if (fs->icache->buffer_blk != block_nr) { |
| retval = io_channel_read_blk(fs->io, block_nr, 1, |
| fs->icache->buffer); |
| if (retval) |
| return retval; |
| fs->icache->buffer_blk = block_nr; |
| } |
| |
| if ((offset + length) > EXT2_BLOCK_SIZE(fs->super)) { |
| clen = (int) (EXT2_BLOCK_SIZE(fs->super) - offset); |
| length -= clen; |
| } else { |
| length = 0; |
| } |
| memcpy(ptr, &temp_inode, clen); |
| retval = io_channel_write_blk(fs->io, block_nr, 1, fs->icache->buffer); |
| if (retval) |
| return retval; |
| |
| if (length) { |
| retval = io_channel_read_blk(fs->io, ++block_nr, 1, |
| fs->icache->buffer); |
| if (retval) { |
| fs->icache->buffer_blk = 0; |
| return retval; |
| } |
| fs->icache->buffer_blk = block_nr; |
| memcpy(fs->icache->buffer, ((char *) &temp_inode) + clen, |
| length); |
| |
| retval = io_channel_write_blk(fs->io, block_nr, 1, |
| fs->icache->buffer); |
| if (retval) |
| return retval; |
| } |
| |
| fs->flags |= EXT2_FLAG_CHANGED; |
| return 0; |
| } |
| |
| errcode_t ext2fs_get_blocks(ext2_filsys fs, ino_t ino, blk_t *blocks) |
| { |
| struct ext2_inode inode; |
| int i; |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (ino > fs->super->s_inodes_count) |
| return EXT2_ET_BAD_INODE_NUM; |
| |
| if (fs->get_blocks) { |
| if (!(*fs->get_blocks)(fs, ino, blocks)) |
| return 0; |
| } |
| retval = ext2fs_read_inode(fs, ino, &inode); |
| if (retval) |
| return retval; |
| for (i=0; i < EXT2_N_BLOCKS; i++) |
| blocks[i] = inode.i_block[i]; |
| return 0; |
| } |
| |
| errcode_t ext2fs_check_directory(ext2_filsys fs, ino_t ino) |
| { |
| struct ext2_inode inode; |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (ino > fs->super->s_inodes_count) |
| return EXT2_ET_BAD_INODE_NUM; |
| |
| if (fs->check_directory) { |
| retval = (fs->check_directory)(fs, ino); |
| if (retval != EXT2_ET_CALLBACK_NOTHANDLED) |
| return retval; |
| } |
| retval = ext2fs_read_inode(fs, ino, &inode); |
| if (retval) |
| return retval; |
| if (!LINUX_S_ISDIR(inode.i_mode)) |
| return EXT2_NO_DIRECTORY; |
| return 0; |
| } |
| |