2 * dir_iterate.c --- ext2fs directory iteration operations
4 * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
24 #define EXT4_MAX_REC_LEN ((1<<16)-1)
26 errcode_t ext2fs_get_rec_len(ext2_filsys fs,
27 struct ext2_dir_entry *dirent,
28 unsigned int *rec_len)
30 unsigned int len = dirent->rec_len;
32 if (fs->blocksize < 65536)
34 else if (len == EXT4_MAX_REC_LEN || len == 0)
35 *rec_len = fs->blocksize;
37 *rec_len = (len & 65532) | ((len & 3) << 16);
41 errcode_t ext2fs_set_rec_len(ext2_filsys fs,
43 struct ext2_dir_entry *dirent)
45 if ((len > fs->blocksize) || (fs->blocksize > (1 << 18)) || (len & 3))
48 dirent->rec_len = len;
51 if (len == fs->blocksize) {
52 if (fs->blocksize == 65536)
53 dirent->rec_len = EXT4_MAX_REC_LEN;
57 dirent->rec_len = (len & 65532) | ((len >> 16) & 3);
62 * This function checks to see whether or not a potential deleted
63 * directory entry looks valid. What we do is check the deleted entry
64 * and each successive entry to make sure that they all look valid and
65 * that the last deleted entry ends at the beginning of the next
66 * undeleted entry. Returns 1 if the deleted entry looks valid, zero
69 static int ext2fs_validate_entry(ext2_filsys fs, char *buf,
71 unsigned int final_offset)
73 struct ext2_dir_entry *dirent;
75 #define DIRENT_MIN_LENGTH 12
77 while ((offset < final_offset) &&
78 (offset <= fs->blocksize - DIRENT_MIN_LENGTH)) {
79 dirent = (struct ext2_dir_entry *)(buf + offset);
80 if (ext2fs_get_rec_len(fs, dirent, &rec_len))
84 ((rec_len % 4) != 0) ||
85 ((((unsigned) dirent->name_len & 0xFF)+8) > rec_len))
88 return (offset == final_offset);
91 errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
95 int (*func)(ext2_ino_t dir,
97 struct ext2_dir_entry *dirent,
104 struct dir_context ctx;
107 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
109 retval = ext2fs_check_directory(fs, dir);
118 retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
123 ctx.priv_data = priv_data;
125 retval = ext2fs_block_iterate3(fs, dir, BLOCK_FLAG_READ_ONLY, 0,
126 ext2fs_process_dir_block, &ctx);
128 ext2fs_free_mem(&ctx.buf);
135 int (*func)(struct ext2_dir_entry *dirent,
143 static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
144 int entry EXT2FS_ATTR((unused)),
145 struct ext2_dir_entry *dirent, int offset,
146 int blocksize, char *buf, void *priv_data)
148 struct xlate *xl = (struct xlate *) priv_data;
150 return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
153 extern errcode_t ext2fs_dir_iterate(ext2_filsys fs,
157 int (*func)(struct ext2_dir_entry *dirent,
166 xl.real_private = priv_data;
169 return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
175 * Helper function which is private to this module. Used by
176 * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
178 int ext2fs_process_dir_block(ext2_filsys fs,
180 e2_blkcnt_t blockcnt,
181 blk64_t ref_block EXT2FS_ATTR((unused)),
182 int ref_offset EXT2FS_ATTR((unused)),
185 struct dir_context *ctx = (struct dir_context *) priv_data;
186 unsigned int offset = 0;
187 unsigned int next_real_entry = 0;
191 unsigned int rec_len, size;
193 struct ext2_dir_entry *dirent;
198 entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
200 ctx->errcode = ext2fs_read_dir_block3(fs, *blocknr, ctx->buf, 0);
204 while (offset < fs->blocksize) {
205 dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
206 if (ext2fs_get_rec_len(fs, dirent, &rec_len))
208 if (((offset + rec_len) > fs->blocksize) ||
210 ((rec_len % 4) != 0) ||
211 ((((unsigned) dirent->name_len & 0xFF)+8) > rec_len)) {
212 ctx->errcode = EXT2_ET_DIR_CORRUPTED;
215 if (!dirent->inode &&
216 !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
219 ret = (ctx->func)(ctx->dir,
220 (next_real_entry > offset) ?
221 DIRENT_DELETED_FILE : entry,
223 fs->blocksize, ctx->buf,
225 if (entry < DIRENT_OTHER_FILE)
228 if (ret & DIRENT_CHANGED) {
229 if (ext2fs_get_rec_len(fs, dirent, &rec_len))
233 if (ret & DIRENT_ABORT) {
238 if (next_real_entry == offset)
239 next_real_entry += rec_len;
241 if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
242 size = ((dirent->name_len & 0xFF) + 11) & ~3;
244 if (rec_len != size) {
245 unsigned int final_offset;
247 final_offset = offset + rec_len;
249 while (offset < final_offset &&
250 !ext2fs_validate_entry(fs, ctx->buf,
261 ctx->errcode = ext2fs_write_dir_block3(fs, *blocknr, ctx->buf,