diff options
Diffstat (limited to 'fs/ext4/format/dir_iterate.c')
| -rwxr-xr-x | fs/ext4/format/dir_iterate.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/fs/ext4/format/dir_iterate.c b/fs/ext4/format/dir_iterate.c new file mode 100755 index 0000000..bf4cbfa --- /dev/null +++ b/fs/ext4/format/dir_iterate.c @@ -0,0 +1,266 @@ +/* + * dir_iterate.c --- ext2fs directory iteration operations + * + * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 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 <common.h> +//#include <ext_common.h> +//#include <ext4fs.h> +#include <malloc.h> +#include <stddef.h> + +#include "ext2_fs.h" +#include "ext2fsP.h" + +#define EXT4_MAX_REC_LEN ((1<<16)-1) + +errcode_t ext2fs_get_rec_len(ext2_filsys fs, + struct ext2_dir_entry *dirent, + unsigned int *rec_len) +{ + unsigned int len = dirent->rec_len; + + if (fs->blocksize < 65536) + *rec_len = len; + else if (len == EXT4_MAX_REC_LEN || len == 0) + *rec_len = fs->blocksize; + else + *rec_len = (len & 65532) | ((len & 3) << 16); + return 0; +} + +errcode_t ext2fs_set_rec_len(ext2_filsys fs, + unsigned int len, + struct ext2_dir_entry *dirent) +{ + if ((len > fs->blocksize) || (fs->blocksize > (1 << 18)) || (len & 3)) + return EINVAL; + if (len < 65536) { + dirent->rec_len = len; + return 0; + } + if (len == fs->blocksize) { + if (fs->blocksize == 65536) + dirent->rec_len = EXT4_MAX_REC_LEN; + else + dirent->rec_len = 0; + } else + dirent->rec_len = (len & 65532) | ((len >> 16) & 3); + return 0; +} + +/* + * This function checks to see whether or not a potential deleted + * directory entry looks valid. What we do is check the deleted entry + * and each successive entry to make sure that they all look valid and + * that the last deleted entry ends at the beginning of the next + * undeleted entry. Returns 1 if the deleted entry looks valid, zero + * if not valid. + */ +static int ext2fs_validate_entry(ext2_filsys fs, char *buf, + unsigned int offset, + unsigned int final_offset) +{ + struct ext2_dir_entry *dirent; + unsigned int rec_len; +#define DIRENT_MIN_LENGTH 12 + + while ((offset < final_offset) && + (offset <= fs->blocksize - DIRENT_MIN_LENGTH)) { + dirent = (struct ext2_dir_entry *)(buf + offset); + if (ext2fs_get_rec_len(fs, dirent, &rec_len)) + return 0; + offset += rec_len; + if ((rec_len < 8) || + ((rec_len % 4) != 0) || + ((((unsigned) dirent->name_len & 0xFF)+8) > rec_len)) + return 0; + } + return (offset == final_offset); +} + +errcode_t ext2fs_dir_iterate2(ext2_filsys fs, + ext2_ino_t dir, + int flags, + char *block_buf, + int (*func)(ext2_ino_t dir, + int entry, + struct ext2_dir_entry *dirent, + int offset, + int blocksize, + char *buf, + void *priv_data), + void *priv_data) +{ + struct dir_context ctx; + errcode_t retval; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + retval = ext2fs_check_directory(fs, dir); + if (retval) + return retval; + + ctx.dir = dir; + ctx.flags = flags; + if (block_buf) + ctx.buf = block_buf; + else { + retval = ext2fs_get_mem(fs->blocksize, &ctx.buf); + if (retval) + return retval; + } + ctx.func = func; + ctx.priv_data = priv_data; + ctx.errcode = 0; + retval = ext2fs_block_iterate2(fs, dir, BLOCK_FLAG_READ_ONLY, 0, + ext2fs_process_dir_block, &ctx); + if (!block_buf) + ext2fs_free_mem(&ctx.buf); + if (retval) + return retval; + return ctx.errcode; +} + +struct xlate { + int (*func)(struct ext2_dir_entry *dirent, + int offset, + int blocksize, + char *buf, + void *priv_data); + void *real_private; +}; + +static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)), + int entry EXT2FS_ATTR((unused)), + struct ext2_dir_entry *dirent, int offset, + int blocksize, char *buf, void *priv_data) +{ + struct xlate *xl = (struct xlate *) priv_data; + + return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private); +} + +extern errcode_t ext2fs_dir_iterate(ext2_filsys fs, + ext2_ino_t dir, + int flags, + char *block_buf, + int (*func)(struct ext2_dir_entry *dirent, + int offset, + int blocksize, + char *buf, + void *priv_data), + void *priv_data) +{ + struct xlate xl; + + xl.real_private = priv_data; + xl.func = func; + + return ext2fs_dir_iterate2(fs, dir, flags, block_buf, + xlate_func, &xl); +} + + +/* + * Helper function which is private to this module. Used by + * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate() + */ +int ext2fs_process_dir_block(ext2_filsys fs, + blk_t *blocknr, + e2_blkcnt_t blockcnt, + blk_t ref_block EXT2FS_ATTR((unused)), + int ref_offset EXT2FS_ATTR((unused)), + void *priv_data) +{ + struct dir_context *ctx = (struct dir_context *) priv_data; + unsigned int offset = 0; + unsigned int next_real_entry = 0; + int ret = 0; + int changed = 0; + int do_abort = 0; + unsigned int rec_len, size; + int entry; + struct ext2_dir_entry *dirent; + + if (blockcnt < 0) + return 0; + + entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE; + + ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf); + if (ctx->errcode) + return BLOCK_ABORT; + + while (offset < fs->blocksize) { + dirent = (struct ext2_dir_entry *) (ctx->buf + offset); + if (ext2fs_get_rec_len(fs, dirent, &rec_len)) + return BLOCK_ABORT; + if (((offset + rec_len) > fs->blocksize) || + (rec_len < 8) || + ((rec_len % 4) != 0) || + ((((unsigned) dirent->name_len & 0xFF)+8) > rec_len)) { + ctx->errcode = EXT2_ET_DIR_CORRUPTED; + return BLOCK_ABORT; + } + if (!dirent->inode && + !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY)) + goto next; + + ret = (ctx->func)(ctx->dir, + (next_real_entry > offset) ? + DIRENT_DELETED_FILE : entry, + dirent, offset, + fs->blocksize, ctx->buf, + ctx->priv_data); + if (entry < DIRENT_OTHER_FILE) + entry++; + + if (ret & DIRENT_CHANGED) { + if (ext2fs_get_rec_len(fs, dirent, &rec_len)) + return BLOCK_ABORT; + changed++; + } + if (ret & DIRENT_ABORT) { + do_abort++; + break; + } +next: + if (next_real_entry == offset) + next_real_entry += rec_len; + + if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) { + size = ((dirent->name_len & 0xFF) + 11) & ~3; + + if (rec_len != size) { + unsigned int final_offset; + + final_offset = offset + rec_len; + offset += size; + while (offset < final_offset && + !ext2fs_validate_entry(fs, ctx->buf, + offset, + final_offset)) + offset += 4; + continue; + } + } + offset += rec_len; + } + + if (changed) { + ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf); + if (ctx->errcode) + return BLOCK_ABORT; + } + if (do_abort) + return BLOCK_ABORT; + return 0; +} + |