/* * 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 #if HAVE_ERRNO_H #include <errno.h> #endif #include <time.h> #if HAVE_SYS_STAT_H #include <sys/stat.h> #endif #if HAVE_SYS_TYPES_H #include <sys/types.h> #endif #include "ext2_fs.h" #include "ext2fsP.h" #include "e2image.h" struct ext2_struct_inode_scan { errcode_t magic; ext2_filsys fs; ext2_ino_t current_inode; blk_t current_block; dgrp_t current_group; ext2_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 * priv_data); void * done_group_data; int bad_block_ptr; int scan_flags; int reserved[6]; }; /* * This routine flushes the icache, if it exists. */ errcode_t ext2fs_flush_icache(ext2_filsys fs) { int i; if (!fs->icache) return 0; for (i=0; i < fs->icache->cache_size; i++) fs->icache->cache[i].ino = 0; fs->icache->buffer_blk = 0; return 0; } static errcode_t create_icache(ext2_filsys fs) { errcode_t retval; if (fs->icache) return 0; retval = ext2fs_get_mem(sizeof(struct ext2_inode_cache), &fs->icache); if (retval) return retval; memset(fs->icache, 0, sizeof(struct ext2_inode_cache)); retval = ext2fs_get_mem(fs->blocksize, &fs->icache->buffer); if (retval) { ext2fs_free_mem(&fs->icache); return retval; } fs->icache->buffer_blk = 0; fs->icache->cache_last = -1; fs->icache->cache_size = 4; fs->icache->refcount = 1; retval = ext2fs_get_array(fs->icache->cache_size, sizeof(struct ext2_inode_cache_ent), &fs->icache->cache); if (retval) { ext2fs_free_mem(&fs->icache->buffer); ext2fs_free_mem(&fs->icache); return retval; } ext2fs_flush_icache(fs); 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, ext2_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) { ext2fs_badblocks_list_free(fs->badblocks); fs->badblocks = 0; } fs->get_blocks = save_get_blocks; } retval = ext2fs_get_mem(sizeof(struct ext2_struct_inode_scan), &scan); if (retval) return retval; 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 = 0; scan->groups_left = fs->group_desc_count - 1; scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8; scan->current_block = scan->fs-> group_desc[scan->current_group].bg_inode_table; scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super); scan->blocks_left = scan->fs->inode_blocks_per_group; if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { scan->inodes_left -= fs->group_desc[scan->current_group].bg_itable_unused; scan->blocks_left = (scan->inodes_left + (fs->blocksize / scan->inode_size - 1)) * scan->inode_size / fs->blocksize; } retval = ext2fs_get_array(scan->inode_buffer_blocks, fs->blocksize, &scan->inode_buffer); scan->done_group = 0; scan->done_group_data = 0; scan->bad_block_ptr = 0; if (retval) { ext2fs_free_mem(&scan); return retval; } retval = ext2fs_get_mem(scan->inode_size, &scan->temp_buffer); if (retval) { ext2fs_free_mem(&scan->inode_buffer); ext2fs_free_mem(&scan); return retval; } if (scan->fs->badblocks && scan->fs->badblocks->num) scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS; if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) scan->scan_flags |= EXT2_SF_DO_LAZY; *ret_scan = scan; return 0; } void ext2fs_close_inode_scan(ext2_inode_scan scan) { if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN)) return; ext2fs_free_mem(&scan->inode_buffer); scan->inode_buffer = NULL; ext2fs_free_mem(&scan->temp_buffer); scan->temp_buffer = NULL; ext2fs_free_mem(&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 * priv_data), 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) { ext2_filsys fs = scan->fs; scan->current_group++; scan->groups_left--; scan->current_block =fs->group_desc[scan->current_group].bg_inode_table; scan->current_inode = scan->current_group * EXT2_INODES_PER_GROUP(fs->super); scan->bytes_left = 0; scan->inodes_left = EXT2_INODES_PER_GROUP(fs->super); scan->blocks_left = fs->inode_blocks_per_group; if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { scan->inodes_left -= fs->group_desc[scan->current_group].bg_itable_unused; scan->blocks_left = (scan->inodes_left + (fs->blocksize / scan->inode_size - 1)) * scan->inode_size / fs->blocksize; } 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; 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; } #if 0 /* * Returns 1 if the entire inode_buffer has a non-zero size and * contains all zeros. (Not just deleted inodes, since that means * that part of the inode table was used at one point; we want all * zeros, which means that the inode table is pristine.) */ static inline int is_empty_scan(ext2_inode_scan scan) { int i; if (scan->bytes_left == 0) return 0; for (i=0; i < scan->bytes_left; i++) if (scan->ptr[i]) return 0; return 1; } #endif errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino, struct ext2_inode *inode, int bufsize) { 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) { force_new_group: 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; } /* * These checks are done outside the above if statement so * they can be done for block group #0. */ if ((scan->scan_flags & EXT2_SF_DO_LAZY) && (scan->fs->group_desc[scan->current_group].bg_flags & EXT2_BG_INODE_UNINIT)) goto force_new_group; if (scan->inodes_left == 0) goto force_new_group; if (scan->current_block == 0) { if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) { goto force_new_group; } 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; #if 0 /* * XXX test Need check for used inode somehow. * (Note: this is hard.) */ if (is_empty_scan(scan)) goto force_new_group; #endif } 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; #ifdef WORDS_BIGENDIAN memset(inode, 0, bufsize); ext2fs_swap_inode_full(scan->fs, (struct ext2_inode_large *) inode, (struct ext2_inode_large *) scan->temp_buffer, 0, bufsize); #else *inode = *((struct ext2_inode *) scan->temp_buffer); #endif 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 { #ifdef WORDS_BIGENDIAN memset(inode, 0, bufsize); ext2fs_swap_inode_full(scan->fs, (struct ext2_inode_large *) inode, (struct ext2_inode_large *) scan->ptr, 0, bufsize); #else memcpy(inode, scan->ptr, bufsize); #endif 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; } errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino, struct ext2_inode *inode) { return ext2fs_get_next_inode_full(scan, ino, inode, sizeof(struct ext2_inode)); } /* * Functions to read and write a single inode. */ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode * inode, int bufsize) { unsigned long group, block, block_nr, offset; char *ptr; errcode_t retval; int clen, i, inodes_per_block, length; io_channel io; 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; } if ((ino == 0) || (ino > fs->super->s_inodes_count)) return EXT2_ET_BAD_INODE_NUM; /* 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 */ if (bufsize == sizeof(struct ext2_inode)) { /* only old good inode can be retrieved from the 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 (fs->flags & EXT2_FLAG_IMAGE_FILE) { inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super); block_nr = fs->image_header->offset_inode / fs->blocksize; block_nr += (ino - 1) / inodes_per_block; offset = ((ino - 1) % inodes_per_block) * EXT2_INODE_SIZE(fs->super); io = fs->image_io; } else { group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super); if (group > fs->group_desc_count) return EXT2_ET_BAD_INODE_NUM; 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; io = fs->io; } offset &= (EXT2_BLOCK_SIZE(fs->super) - 1); length = EXT2_INODE_SIZE(fs->super); if (bufsize < length) length = bufsize; ptr = (char *) inode; while (length) { clen = length; if ((offset + length) > fs->blocksize) clen = fs->blocksize - offset; if (block_nr != fs->icache->buffer_blk) { retval = io_channel_read_blk(io, block_nr, 1, fs->icache->buffer); if (retval) return retval; fs->icache->buffer_blk = block_nr; } memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset, clen); offset = 0; length -= clen; ptr += clen; block_nr++; } #ifdef WORDS_BIGENDIAN ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode, (struct ext2_inode_large *) inode, 0, bufsize); #endif /* 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_read_inode(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode * inode) { return ext2fs_read_inode_full(fs, ino, inode, sizeof(struct ext2_inode)); } errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode * inode, int bufsize) { unsigned long group, block, block_nr, offset; errcode_t retval = 0; struct ext2_inode_large temp_inode, *w_inode; char *ptr; int clen, i, length; 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 == 0) || (ino > fs->super->s_inodes_count)) return EXT2_ET_BAD_INODE_NUM; length = bufsize; if (length < EXT2_INODE_SIZE(fs->super)) length = EXT2_INODE_SIZE(fs->super); if (length > (int) sizeof(struct ext2_inode_large)) { w_inode = malloc(length); if (!w_inode) return ENOMEM; } else w_inode = &temp_inode; memset(w_inode, 0, length); #ifdef WORDS_BIGENDIAN ext2fs_swap_inode_full(fs, w_inode, (struct ext2_inode_large *) inode, 1, bufsize); #else memcpy(w_inode, inode, bufsize); #endif 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) { retval = EXT2_ET_MISSING_INODE_TABLE; goto errout; } block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block; offset &= (EXT2_BLOCK_SIZE(fs->super) - 1); length = EXT2_INODE_SIZE(fs->super); if (length > bufsize) length = bufsize; ptr = (char *) w_inode; while (length) { clen = length; if ((offset + length) > fs->blocksize) clen = fs->blocksize - offset; if (fs->icache->buffer_blk != block_nr) { retval = io_channel_read_blk(fs->io, block_nr, 1, fs->icache->buffer); if (retval) goto errout; fs->icache->buffer_blk = block_nr; } memcpy((char *) fs->icache->buffer + (unsigned) offset, ptr, clen); retval = io_channel_write_blk(fs->io, block_nr, 1, fs->icache->buffer); if (retval) goto errout; offset = 0; ptr += clen; length -= clen; block_nr++; } fs->flags |= EXT2_FLAG_CHANGED; errout: if (w_inode && w_inode != &temp_inode) free(w_inode); return retval; } errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode) { return ext2fs_write_inode_full(fs, ino, inode, sizeof(struct ext2_inode)); } /* * This function should be called when writing a new inode. It makes * sure that extra part of large inodes is initialized properly. */ errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode) { struct ext2_inode *buf; int size = EXT2_INODE_SIZE(fs->super); struct ext2_inode_large *large_inode; errcode_t retval; __u32 t = fs->now ? fs->now : time(NULL); if (!inode->i_ctime) inode->i_ctime = t; if (!inode->i_mtime) inode->i_mtime = t; if (!inode->i_atime) inode->i_atime = t; if (size == sizeof(struct ext2_inode)) return ext2fs_write_inode_full(fs, ino, inode, sizeof(struct ext2_inode)); buf = malloc(size); if (!buf) return ENOMEM; memset(buf, 0, size); *buf = *inode; large_inode = (struct ext2_inode_large *) buf; large_inode->i_extra_isize = sizeof(struct ext2_inode_large) - EXT2_GOOD_OLD_INODE_SIZE; if (!large_inode->i_crtime) large_inode->i_crtime = t; retval = ext2fs_write_inode_full(fs, ino, buf, size); free(buf); return retval; } errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_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, ext2_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_ET_NO_DIRECTORY; return 0; }