b7d873595a62a9ac75fc80e30f9f6fe5d3d7b33c
[external/busybox.git] / e2fsprogs / old_e2fsprogs / ext2fs / dir_iterate.c
1 /* vi: set sw=4 ts=4: */
2 /*
3  * dir_iterate.c --- ext2fs directory iteration operations
4  *
5  * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o.
6  *
7  * %Begin-Header%
8  * This file may be redistributed under the terms of the GNU Public
9  * License.
10  * %End-Header%
11  */
12
13 #include <stdio.h>
14 #include <string.h>
15 #if HAVE_UNISTD_H
16 #include <unistd.h>
17 #endif
18 #if HAVE_ERRNO_H
19 #include <errno.h>
20 #endif
21
22 #include "ext2_fs.h"
23 #include "ext2fsP.h"
24
25 /*
26  * This function checks to see whether or not a potential deleted
27  * directory entry looks valid.  What we do is check the deleted entry
28  * and each successive entry to make sure that they all look valid and
29  * that the last deleted entry ends at the beginning of the next
30  * undeleted entry.  Returns 1 if the deleted entry looks valid, zero
31  * if not valid.
32  */
33 static int ext2fs_validate_entry(char *buf, int offset, int final_offset)
34 {
35         struct ext2_dir_entry *dirent;
36
37         while (offset < final_offset) {
38                 dirent = (struct ext2_dir_entry *)(buf + offset);
39                 offset += dirent->rec_len;
40                 if ((dirent->rec_len < 8) ||
41                     ((dirent->rec_len % 4) != 0) ||
42                     (((dirent->name_len & 0xFF)+8) > dirent->rec_len))
43                         return 0;
44         }
45         return (offset == final_offset);
46 }
47
48 errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
49                               ext2_ino_t dir,
50                               int flags,
51                               char *block_buf,
52                               int (*func)(ext2_ino_t    dir,
53                                           int           entry,
54                                           struct ext2_dir_entry *dirent,
55                                           int   offset,
56                                           int   blocksize,
57                                           char  *buf,
58                                           void  *priv_data),
59                               void *priv_data)
60 {
61         struct          dir_context     ctx;
62         errcode_t       retval;
63
64         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
65
66         retval = ext2fs_check_directory(fs, dir);
67         if (retval)
68                 return retval;
69
70         ctx.dir = dir;
71         ctx.flags = flags;
72         if (block_buf)
73                 ctx.buf = block_buf;
74         else {
75                 retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
76                 if (retval)
77                         return retval;
78         }
79         ctx.func = func;
80         ctx.priv_data = priv_data;
81         ctx.errcode = 0;
82         retval = ext2fs_block_iterate2(fs, dir, 0, 0,
83                                        ext2fs_process_dir_block, &ctx);
84         if (!block_buf)
85                 ext2fs_free_mem(&ctx.buf);
86         if (retval)
87                 return retval;
88         return ctx.errcode;
89 }
90
91 struct xlate {
92         int (*func)(struct ext2_dir_entry *dirent,
93                     int         offset,
94                     int         blocksize,
95                     char        *buf,
96                     void        *priv_data);
97         void *real_private;
98 };
99
100 static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
101                       int entry EXT2FS_ATTR((unused)),
102                       struct ext2_dir_entry *dirent, int offset,
103                       int blocksize, char *buf, void *priv_data)
104 {
105         struct xlate *xl = (struct xlate *) priv_data;
106
107         return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
108 }
109
110 extern errcode_t ext2fs_dir_iterate(ext2_filsys fs,
111                               ext2_ino_t dir,
112                               int flags,
113                               char *block_buf,
114                               int (*func)(struct ext2_dir_entry *dirent,
115                                           int   offset,
116                                           int   blocksize,
117                                           char  *buf,
118                                           void  *priv_data),
119                               void *priv_data)
120 {
121         struct xlate xl;
122
123         xl.real_private = priv_data;
124         xl.func = func;
125
126         return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
127                                    xlate_func, &xl);
128 }
129
130
131 /*
132  * Helper function which is private to this module.  Used by
133  * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
134  */
135 int ext2fs_process_dir_block(ext2_filsys fs,
136                              blk_t      *blocknr,
137                              e2_blkcnt_t blockcnt,
138                              blk_t      ref_block EXT2FS_ATTR((unused)),
139                              int        ref_offset EXT2FS_ATTR((unused)),
140                              void       *priv_data)
141 {
142         struct dir_context *ctx = (struct dir_context *) priv_data;
143         unsigned int    offset = 0;
144         unsigned int    next_real_entry = 0;
145         int             ret = 0;
146         int             changed = 0;
147         int             do_abort = 0;
148         int             entry, size;
149         struct ext2_dir_entry *dirent;
150
151         if (blockcnt < 0)
152                 return 0;
153
154         entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
155
156         ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
157         if (ctx->errcode)
158                 return BLOCK_ABORT;
159
160         while (offset < fs->blocksize) {
161                 dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
162                 if (((offset + dirent->rec_len) > fs->blocksize) ||
163                     (dirent->rec_len < 8) ||
164                     ((dirent->rec_len % 4) != 0) ||
165                     (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) {
166                         ctx->errcode = EXT2_ET_DIR_CORRUPTED;
167                         return BLOCK_ABORT;
168                 }
169                 if (!dirent->inode &&
170                     !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
171                         goto next;
172
173                 ret = (ctx->func)(ctx->dir,
174                                   (next_real_entry > offset) ?
175                                   DIRENT_DELETED_FILE : entry,
176                                   dirent, offset,
177                                   fs->blocksize, ctx->buf,
178                                   ctx->priv_data);
179                 if (entry < DIRENT_OTHER_FILE)
180                         entry++;
181
182                 if (ret & DIRENT_CHANGED)
183                         changed++;
184                 if (ret & DIRENT_ABORT) {
185                         do_abort++;
186                         break;
187                 }
188 next:
189                 if (next_real_entry == offset)
190                         next_real_entry += dirent->rec_len;
191
192                 if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
193                         size = ((dirent->name_len & 0xFF) + 11) & ~3;
194
195                         if (dirent->rec_len != size)  {
196                                 unsigned int final_offset;
197
198                                 final_offset = offset + dirent->rec_len;
199                                 offset += size;
200                                 while (offset < final_offset &&
201                                        !ext2fs_validate_entry(ctx->buf,
202                                                               offset,
203                                                               final_offset))
204                                         offset += 4;
205                                 continue;
206                         }
207                 }
208                 offset += dirent->rec_len;
209         }
210
211         if (changed) {
212                 ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
213                 if (ctx->errcode)
214                         return BLOCK_ABORT;
215         }
216         if (do_abort)
217                 return BLOCK_ABORT;
218         return 0;
219 }
220