1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/*
* namei.c --- ext2fs directory lookup operations
*
* Copyright (C) 1993, 1994, 1994, 1995 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
/* #define NAMEI_DEBUG */
#include "ext2_fs.h"
#include "ext2fs.h"
static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
const char *pathname, size_t pathlen, int follow,
int link_count, char *buf, ext2_ino_t *res_inode);
static errcode_t follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
ext2_ino_t inode, int link_count,
char *buf, ext2_ino_t *res_inode)
{
char *pathname;
char *buffer = 0;
errcode_t retval;
struct ext2_inode ei;
#ifdef NAMEI_DEBUG
printf("follow_link: root=%lu, dir=%lu, inode=%lu, lc=%d\n",
root, dir, inode, link_count);
#endif
retval = ext2fs_read_inode (fs, inode, &ei);
if (retval) return retval;
if (!LINUX_S_ISLNK (ei.i_mode)) {
*res_inode = inode;
return 0;
}
if (link_count++ > 5) {
return EXT2_ET_SYMLINK_LOOP;
}
if (ext2fs_inode_data_blocks(fs,&ei)) {
retval = ext2fs_get_mem(fs->blocksize, &buffer);
if (retval)
return retval;
retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer);
if (retval) {
ext2fs_free_mem(&buffer);
return retval;
}
pathname = buffer;
} else
pathname = (char *)&(ei.i_block[0]);
retval = open_namei(fs, root, dir, pathname, ei.i_size, 1,
link_count, buf, res_inode);
if (buffer)
ext2fs_free_mem(&buffer);
return retval;
}
/*
* This routine interprets a pathname in the context of the current
* directory and the root directory, and returns the inode of the
* containing directory, and a pointer to the filename of the file
* (pointing into the pathname) and the length of the filename.
*/
static errcode_t dir_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
const char *pathname, int pathlen,
int link_count, char *buf,
const char **name, int *namelen,
ext2_ino_t *res_inode)
{
char c;
const char *thisname;
int len;
ext2_ino_t inode;
errcode_t retval;
if ((c = *pathname) == '/') {
dir = root;
pathname++;
pathlen--;
}
while (1) {
thisname = pathname;
for (len=0; --pathlen >= 0;len++) {
c = *(pathname++);
if (c == '/')
break;
}
if (pathlen < 0)
break;
retval = ext2fs_lookup (fs, dir, thisname, len, buf, &inode);
if (retval) return retval;
retval = follow_link (fs, root, dir, inode,
link_count, buf, &dir);
if (retval) return retval;
}
*name = thisname;
*namelen = len;
*res_inode = dir;
return 0;
}
static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
const char *pathname, size_t pathlen, int follow,
int link_count, char *buf, ext2_ino_t *res_inode)
{
const char *basename;
int namelen;
ext2_ino_t dir, inode;
errcode_t retval;
#ifdef NAMEI_DEBUG
printf("open_namei: root=%lu, dir=%lu, path=%*s, lc=%d\n",
root, base, pathlen, pathname, link_count);
#endif
retval = dir_namei(fs, root, base, pathname, pathlen,
link_count, buf, &basename, &namelen, &dir);
if (retval) return retval;
if (!namelen) { /* special case: '/usr/' etc */
*res_inode=dir;
return 0;
}
retval = ext2fs_lookup (fs, dir, basename, namelen, buf, &inode);
if (retval)
return retval;
if (follow) {
retval = follow_link(fs, root, dir, inode, link_count,
buf, &inode);
if (retval)
return retval;
}
#ifdef NAMEI_DEBUG
printf("open_namei: (link_count=%d) returns %lu\n",
link_count, inode);
#endif
*res_inode = inode;
return 0;
}
errcode_t ext2fs_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
const char *name, ext2_ino_t *inode)
{
char *buf;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
return retval;
retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0,
buf, inode);
ext2fs_free_mem(&buf);
return retval;
}
errcode_t ext2fs_namei_follow(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
const char *name, ext2_ino_t *inode)
{
char *buf;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
return retval;
retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0,
buf, inode);
ext2fs_free_mem(&buf);
return retval;
}
errcode_t ext2fs_follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
ext2_ino_t inode, ext2_ino_t *res_inode)
{
char *buf;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
return retval;
retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode);
ext2fs_free_mem(&buf);
return retval;
}
|
