blob: 988967009b1adf366d2094257551ce64cb919f80 [file] [log] [blame]
"Robert P. J. Day"63fc1a92006-07-02 19:47:05 +00001/* vi: set sw=4 ts=4: */
Mike Frysinger1fd98e02005-05-09 22:10:42 +00002/*
3 * namei.c --- ext2fs directory lookup operations
Tim Rikerc1ef7bd2006-01-25 00:08:53 +00004 *
Mike Frysinger1fd98e02005-05-09 22:10:42 +00005 * Copyright (C) 1993, 1994, 1994, 1995 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
19/* #define NAMEI_DEBUG */
20
21#include "ext2_fs.h"
22#include "ext2fs.h"
23
24static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
25 const char *pathname, size_t pathlen, int follow,
26 int link_count, char *buf, ext2_ino_t *res_inode);
27
28static errcode_t follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
29 ext2_ino_t inode, int link_count,
30 char *buf, ext2_ino_t *res_inode)
31{
32 char *pathname;
33 char *buffer = 0;
34 errcode_t retval;
35 struct ext2_inode ei;
36
37#ifdef NAMEI_DEBUG
38 printf("follow_link: root=%lu, dir=%lu, inode=%lu, lc=%d\n",
39 root, dir, inode, link_count);
Tim Rikerc1ef7bd2006-01-25 00:08:53 +000040
Mike Frysinger1fd98e02005-05-09 22:10:42 +000041#endif
42 retval = ext2fs_read_inode (fs, inode, &ei);
43 if (retval) return retval;
44 if (!LINUX_S_ISLNK (ei.i_mode)) {
45 *res_inode = inode;
46 return 0;
47 }
48 if (link_count++ > 5) {
49 return EXT2_ET_SYMLINK_LOOP;
50 }
51 if (ext2fs_inode_data_blocks(fs,&ei)) {
52 retval = ext2fs_get_mem(fs->blocksize, &buffer);
53 if (retval)
54 return retval;
55 retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer);
56 if (retval) {
57 ext2fs_free_mem(&buffer);
58 return retval;
59 }
60 pathname = buffer;
61 } else
62 pathname = (char *)&(ei.i_block[0]);
63 retval = open_namei(fs, root, dir, pathname, ei.i_size, 1,
64 link_count, buf, res_inode);
Rob Landleye7c43b62006-03-01 16:39:45 +000065 ext2fs_free_mem(&buffer);
Mike Frysinger1fd98e02005-05-09 22:10:42 +000066 return retval;
67}
68
69/*
70 * This routine interprets a pathname in the context of the current
71 * directory and the root directory, and returns the inode of the
72 * containing directory, and a pointer to the filename of the file
73 * (pointing into the pathname) and the length of the filename.
74 */
75static errcode_t dir_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
76 const char *pathname, int pathlen,
77 int link_count, char *buf,
78 const char **name, int *namelen,
79 ext2_ino_t *res_inode)
80{
81 char c;
82 const char *thisname;
83 int len;
84 ext2_ino_t inode;
85 errcode_t retval;
86
87 if ((c = *pathname) == '/') {
Tim Rikerc1ef7bd2006-01-25 00:08:53 +000088 dir = root;
Mike Frysinger1fd98e02005-05-09 22:10:42 +000089 pathname++;
90 pathlen--;
91 }
92 while (1) {
Tim Rikerc1ef7bd2006-01-25 00:08:53 +000093 thisname = pathname;
Mike Frysinger1fd98e02005-05-09 22:10:42 +000094 for (len=0; --pathlen >= 0;len++) {
95 c = *(pathname++);
96 if (c == '/')
97 break;
98 }
99 if (pathlen < 0)
100 break;
101 retval = ext2fs_lookup (fs, dir, thisname, len, buf, &inode);
102 if (retval) return retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000103 retval = follow_link (fs, root, dir, inode,
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000104 link_count, buf, &dir);
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000105 if (retval) return retval;
106 }
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000107 *name = thisname;
108 *namelen = len;
109 *res_inode = dir;
110 return 0;
111}
112
113static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
114 const char *pathname, size_t pathlen, int follow,
115 int link_count, char *buf, ext2_ino_t *res_inode)
116{
117 const char *basename;
118 int namelen;
119 ext2_ino_t dir, inode;
120 errcode_t retval;
121
122#ifdef NAMEI_DEBUG
123 printf("open_namei: root=%lu, dir=%lu, path=%*s, lc=%d\n",
124 root, base, pathlen, pathname, link_count);
125#endif
126 retval = dir_namei(fs, root, base, pathname, pathlen,
127 link_count, buf, &basename, &namelen, &dir);
128 if (retval) return retval;
129 if (!namelen) { /* special case: '/usr/' etc */
130 *res_inode=dir;
131 return 0;
132 }
133 retval = ext2fs_lookup (fs, dir, basename, namelen, buf, &inode);
134 if (retval)
135 return retval;
136 if (follow) {
137 retval = follow_link(fs, root, dir, inode, link_count,
138 buf, &inode);
139 if (retval)
140 return retval;
141 }
142#ifdef NAMEI_DEBUG
143 printf("open_namei: (link_count=%d) returns %lu\n",
144 link_count, inode);
145#endif
146 *res_inode = inode;
147 return 0;
148}
149
150errcode_t ext2fs_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
151 const char *name, ext2_ino_t *inode)
152{
153 char *buf;
154 errcode_t retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000155
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000156 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
157
158 retval = ext2fs_get_mem(fs->blocksize, &buf);
159 if (retval)
160 return retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000161
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000162 retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0,
163 buf, inode);
164
165 ext2fs_free_mem(&buf);
166 return retval;
167}
168
169errcode_t ext2fs_namei_follow(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
170 const char *name, ext2_ino_t *inode)
171{
172 char *buf;
173 errcode_t retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000174
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000175 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
176
177 retval = ext2fs_get_mem(fs->blocksize, &buf);
178 if (retval)
179 return retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000180
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000181 retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0,
182 buf, inode);
183
184 ext2fs_free_mem(&buf);
185 return retval;
186}
187
188errcode_t ext2fs_follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
189 ext2_ino_t inode, ext2_ino_t *res_inode)
190{
191 char *buf;
192 errcode_t retval;
Tim Rikerc1ef7bd2006-01-25 00:08:53 +0000193
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000194 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
195
196 retval = ext2fs_get_mem(fs->blocksize, &buf);
197 if (retval)
198 return retval;
199
200 retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode);
201
202 ext2fs_free_mem(&buf);
203 return retval;
204}
205