source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/dir_iterate.c@ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 18 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)
File size: 5.1 KB
RevLine 
[821]1/*
2 * dir_iterate.c --- ext2fs directory iteration operations
3 *
4 * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#include <string.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#if HAVE_ERRNO_H
18#include <errno.h>
19#endif
20
21#include "ext2_fs.h"
22#include "ext2fsP.h"
23
24/*
25 * This function checks to see whether or not a potential deleted
26 * directory entry looks valid. What we do is check the deleted entry
27 * and each successive entry to make sure that they all look valid and
28 * that the last deleted entry ends at the beginning of the next
29 * undeleted entry. Returns 1 if the deleted entry looks valid, zero
30 * if not valid.
31 */
32static int ext2fs_validate_entry(char *buf, int offset, int final_offset)
33{
34 struct ext2_dir_entry *dirent;
35
36 while (offset < final_offset) {
37 dirent = (struct ext2_dir_entry *)(buf + offset);
38 offset += dirent->rec_len;
39 if ((dirent->rec_len < 8) ||
40 ((dirent->rec_len % 4) != 0) ||
41 (((dirent->name_len & 0xFF)+8) > dirent->rec_len))
42 return 0;
43 }
44 return (offset == final_offset);
45}
46
47errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
48 ext2_ino_t dir,
49 int flags,
50 char *block_buf,
51 int (*func)(ext2_ino_t dir,
52 int entry,
53 struct ext2_dir_entry *dirent,
54 int offset,
55 int blocksize,
56 char *buf,
57 void *priv_data),
58 void *priv_data)
59{
60 struct dir_context ctx;
61 errcode_t retval;
62
63 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
64
65 retval = ext2fs_check_directory(fs, dir);
66 if (retval)
67 return retval;
68
69 ctx.dir = dir;
70 ctx.flags = flags;
71 if (block_buf)
72 ctx.buf = block_buf;
73 else {
74 retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
75 if (retval)
76 return retval;
77 }
78 ctx.func = func;
79 ctx.priv_data = priv_data;
80 ctx.errcode = 0;
81 retval = ext2fs_block_iterate2(fs, dir, 0, 0,
82 ext2fs_process_dir_block, &ctx);
83 if (!block_buf)
84 ext2fs_free_mem(&ctx.buf);
85 if (retval)
86 return retval;
87 return ctx.errcode;
88}
89
90struct xlate {
91 int (*func)(struct ext2_dir_entry *dirent,
92 int offset,
93 int blocksize,
94 char *buf,
95 void *priv_data);
96 void *real_private;
97};
98
99static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
100 int entry EXT2FS_ATTR((unused)),
101 struct ext2_dir_entry *dirent, int offset,
102 int blocksize, char *buf, void *priv_data)
103{
104 struct xlate *xl = (struct xlate *) priv_data;
105
106 return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
107}
108
109extern errcode_t ext2fs_dir_iterate(ext2_filsys fs,
110 ext2_ino_t dir,
111 int flags,
112 char *block_buf,
113 int (*func)(struct ext2_dir_entry *dirent,
114 int offset,
115 int blocksize,
116 char *buf,
117 void *priv_data),
118 void *priv_data)
119{
120 struct xlate xl;
121
122 xl.real_private = priv_data;
123 xl.func = func;
124
125 return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
126 xlate_func, &xl);
127}
128
129
130/*
131 * Helper function which is private to this module. Used by
132 * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
133 */
134int ext2fs_process_dir_block(ext2_filsys fs,
135 blk_t *blocknr,
136 e2_blkcnt_t blockcnt,
137 blk_t ref_block EXT2FS_ATTR((unused)),
138 int ref_offset EXT2FS_ATTR((unused)),
139 void *priv_data)
140{
141 struct dir_context *ctx = (struct dir_context *) priv_data;
142 unsigned int offset = 0;
143 unsigned int next_real_entry = 0;
144 int ret = 0;
145 int changed = 0;
146 int do_abort = 0;
147 int entry, size;
148 struct ext2_dir_entry *dirent;
149
150 if (blockcnt < 0)
151 return 0;
152
153 entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
154
155 ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
156 if (ctx->errcode)
157 return BLOCK_ABORT;
158
159 while (offset < fs->blocksize) {
160 dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
161 if (((offset + dirent->rec_len) > fs->blocksize) ||
162 (dirent->rec_len < 8) ||
163 ((dirent->rec_len % 4) != 0) ||
164 (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) {
165 ctx->errcode = EXT2_ET_DIR_CORRUPTED;
166 return BLOCK_ABORT;
167 }
168 if (!dirent->inode &&
169 !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
170 goto next;
171
172 ret = (ctx->func)(ctx->dir,
173 (next_real_entry > offset) ?
174 DIRENT_DELETED_FILE : entry,
175 dirent, offset,
176 fs->blocksize, ctx->buf,
177 ctx->priv_data);
178 if (entry < DIRENT_OTHER_FILE)
179 entry++;
180
181 if (ret & DIRENT_CHANGED)
182 changed++;
183 if (ret & DIRENT_ABORT) {
184 do_abort++;
185 break;
186 }
187next:
188 if (next_real_entry == offset)
189 next_real_entry += dirent->rec_len;
190
191 if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
192 size = ((dirent->name_len & 0xFF) + 11) & ~3;
193
194 if (dirent->rec_len != size) {
195 unsigned int final_offset;
196
197 final_offset = offset + dirent->rec_len;
198 offset += size;
199 while (offset < final_offset &&
200 !ext2fs_validate_entry(ctx->buf,
201 offset,
202 final_offset))
203 offset += 4;
204 continue;
205 }
206 }
207 offset += dirent->rec_len;
208 }
209
210 if (changed) {
211 ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
212 if (ctx->errcode)
213 return BLOCK_ABORT;
214 }
215 if (do_abort)
216 return BLOCK_ABORT;
217 return 0;
218}
219
Note: See TracBrowser for help on using the repository browser.