|
428
|
1 /*
|
|
|
2 * realpath.c -- canonicalize pathname by removing symlinks
|
|
|
3 * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
|
|
|
4 *
|
|
|
5
|
|
|
6 This file is part of XEmacs.
|
|
|
7
|
|
|
8 XEmacs is free software; you can redistribute it and/or modify it
|
|
|
9 under the terms of the GNU General Public License as published by the
|
|
|
10 Free Software Foundation; either version 2, or (at your option) any
|
|
|
11 later version.
|
|
|
12
|
|
|
13 XEmacs is distributed in the hope that it will be useful, but WITHOUT
|
|
|
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
|
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
|
16 for more details.
|
|
|
17
|
|
|
18 You should have received a copy of the GNU General Public License
|
|
|
19 along with XEmacs; see the file COPYING. If not, write to
|
|
|
20 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
|
21 Boston, MA 02111-1307, USA. */
|
|
|
22
|
|
|
23 /* Synched up with: Not in FSF. */
|
|
|
24
|
|
|
25 #include <config.h>
|
|
|
26
|
|
|
27 #include <sys/types.h>
|
|
|
28 #include <stdio.h>
|
|
|
29 #include <string.h>
|
|
|
30 #include <errno.h>
|
|
442
|
31 #include <limits.h>
|
|
|
32
|
|
428
|
33 #ifdef HAVE_UNISTD_H
|
|
|
34 #include <unistd.h>
|
|
|
35 #endif
|
|
442
|
36
|
|
|
37 #if defined (HAVE_SYS_PARAM_H)
|
|
|
38 #include <sys/param.h>
|
|
428
|
39 #endif
|
|
|
40
|
|
442
|
41 #ifdef WIN32_NATIVE
|
|
428
|
42 #include <direct.h>
|
|
|
43 #endif
|
|
|
44
|
|
|
45 #include <sys/stat.h> /* for S_IFLNK */
|
|
|
46
|
|
440
|
47 #if !defined (HAVE_GETCWD) && defined (HAVE_GETWD)
|
|
|
48 #undef getcwd
|
|
|
49 #define getcwd(buffer, len) getwd (buffer)
|
|
|
50 #endif
|
|
|
51
|
|
428
|
52 #ifndef PATH_MAX
|
|
440
|
53 # if defined (_POSIX_PATH_MAX)
|
|
|
54 # define PATH_MAX _POSIX_PATH_MAX
|
|
|
55 # elif defined (MAXPATHLEN)
|
|
|
56 # define PATH_MAX MAXPATHLEN
|
|
|
57 # else
|
|
|
58 # define PATH_MAX 1024
|
|
|
59 # endif
|
|
428
|
60 #endif
|
|
|
61
|
|
|
62 #define MAX_READLINKS 32
|
|
|
63
|
|
440
|
64 char * xrealpath (const char *path, char resolved_path []);
|
|
428
|
65 char *
|
|
|
66 xrealpath (const char *path, char resolved_path [])
|
|
|
67 {
|
|
|
68 char copy_path[PATH_MAX];
|
|
|
69 char *new_path = resolved_path;
|
|
|
70 char *max_path;
|
|
|
71 #ifdef S_IFLNK
|
|
|
72 int readlinks = 0;
|
|
|
73 char link_path[PATH_MAX];
|
|
|
74 int n;
|
|
|
75 #endif
|
|
|
76
|
|
|
77 /* Make a copy of the source path since we may need to modify it. */
|
|
442
|
78 strcpy (copy_path, path);
|
|
428
|
79 path = copy_path;
|
|
|
80 max_path = copy_path + PATH_MAX - 2;
|
|
442
|
81 #ifdef WIN32_NATIVE
|
|
428
|
82 /*
|
|
|
83 ** In NT we have two different cases: (1) the path name begins
|
|
|
84 ** with a drive letter, e.g., "C:"; and (2) the path name begins
|
|
|
85 ** with just a slash, which roots to the current drive. In the
|
|
|
86 ** first case we are going to leave things alone, in the second
|
|
|
87 ** case we will prepend the drive letter to the given path.
|
|
|
88 ** Note: So far in testing, I'm only seeing case #1, even though
|
|
|
89 ** I've tried to get the other cases to happen.
|
|
|
90 ** August Hill, 31 Aug 1997.
|
|
|
91 **
|
|
|
92 ** Check for a driver letter...C:/...
|
|
|
93 */
|
|
|
94 if (*(path + 1) == ':')
|
|
|
95 {
|
|
|
96 strncpy(new_path, path, 3);
|
|
|
97 new_path += 3;
|
|
|
98 path += 3;
|
|
|
99 }
|
|
|
100
|
|
|
101 /*
|
|
|
102 ** No drive letter, but a beginning slash? Prepend the drive
|
|
|
103 ** letter...
|
|
|
104 */
|
|
|
105 else if (*path == '/')
|
|
|
106 {
|
|
440
|
107 getcwd (new_path, PATH_MAX - 1);
|
|
428
|
108 new_path += 3;
|
|
|
109 path++;
|
|
|
110 }
|
|
|
111
|
|
|
112 /*
|
|
|
113 ** Just a path name, prepend the current directory
|
|
|
114 */
|
|
|
115 else
|
|
|
116 {
|
|
440
|
117 getcwd (new_path, PATH_MAX - 1);
|
|
428
|
118 new_path += strlen(new_path);
|
|
|
119 if (new_path[-1] != '/')
|
|
|
120 *new_path++ = '/';
|
|
|
121 }
|
|
|
122
|
|
|
123 #else
|
|
440
|
124 /* If it's a relative pathname use getcwd for starters. */
|
|
428
|
125 if (*path != '/')
|
|
|
126 {
|
|
440
|
127 getcwd (new_path, PATH_MAX - 1);
|
|
428
|
128 new_path += strlen(new_path);
|
|
|
129 if (new_path[-1] != '/')
|
|
|
130 *new_path++ = '/';
|
|
|
131 }
|
|
|
132 else
|
|
|
133 {
|
|
|
134 *new_path++ = '/';
|
|
|
135 path++;
|
|
|
136 }
|
|
|
137 #endif
|
|
|
138 /* Expand each slash-separated pathname component. */
|
|
|
139 while (*path != '\0')
|
|
|
140 {
|
|
|
141 /* Ignore stray "/". */
|
|
|
142 if (*path == '/')
|
|
|
143 {
|
|
|
144 path++;
|
|
|
145 continue;
|
|
|
146 }
|
|
|
147
|
|
|
148 if (*path == '.')
|
|
|
149 {
|
|
|
150 /* Ignore ".". */
|
|
|
151 if (path[1] == '\0' || path[1] == '/')
|
|
|
152 {
|
|
|
153 path++;
|
|
|
154 continue;
|
|
|
155 }
|
|
|
156
|
|
442
|
157 /* Handle ".." */
|
|
|
158 if (path[1] == '.' &&
|
|
|
159 (path[2] == '\0' || path[2] == '/'))
|
|
428
|
160 {
|
|
442
|
161 path += 2;
|
|
428
|
162
|
|
442
|
163 /* Ignore ".." at root. */
|
|
|
164 if (new_path == resolved_path + 1)
|
|
|
165 continue;
|
|
428
|
166
|
|
442
|
167 /* Handle ".." by backing up. */
|
|
|
168 while ((--new_path)[-1] != '/')
|
|
|
169 ;
|
|
|
170 continue;
|
|
428
|
171 }
|
|
|
172 }
|
|
|
173
|
|
|
174 /* Safely copy the next pathname component. */
|
|
|
175 while (*path != '\0' && *path != '/')
|
|
|
176 {
|
|
|
177 if (path > max_path)
|
|
|
178 {
|
|
|
179 errno = ENAMETOOLONG;
|
|
|
180 return NULL;
|
|
|
181 }
|
|
|
182 *new_path++ = *path++;
|
|
|
183 }
|
|
|
184
|
|
|
185 #ifdef S_IFLNK
|
|
|
186 /* See if latest pathname component is a symlink. */
|
|
|
187 *new_path = '\0';
|
|
442
|
188 n = readlink (resolved_path, link_path, PATH_MAX - 1);
|
|
428
|
189
|
|
|
190 if (n < 0)
|
|
|
191 {
|
|
|
192 /* EINVAL means the file exists but isn't a symlink. */
|
|
|
193 if (errno != EINVAL)
|
|
|
194 return NULL;
|
|
|
195 }
|
|
|
196 else
|
|
|
197 {
|
|
|
198 /* Protect against infinite loops. */
|
|
|
199 if (readlinks++ > MAX_READLINKS)
|
|
|
200 {
|
|
|
201 errno = ELOOP;
|
|
|
202 return NULL;
|
|
|
203 }
|
|
|
204
|
|
|
205 /* Note: readlink doesn't add the null byte. */
|
|
|
206 link_path[n] = '\0';
|
|
|
207
|
|
|
208 if (*link_path == '/')
|
|
|
209 /* Start over for an absolute symlink. */
|
|
|
210 new_path = resolved_path;
|
|
|
211 else
|
|
|
212 /* Otherwise back up over this component. */
|
|
|
213 while (*(--new_path) != '/')
|
|
|
214 ;
|
|
|
215
|
|
|
216 /* Safe sex check. */
|
|
|
217 if (strlen(path) + n >= PATH_MAX)
|
|
|
218 {
|
|
|
219 errno = ENAMETOOLONG;
|
|
|
220 return NULL;
|
|
|
221 }
|
|
|
222
|
|
|
223 /* Insert symlink contents into path. */
|
|
|
224 strcat(link_path, path);
|
|
|
225 strcpy(copy_path, link_path);
|
|
|
226 path = copy_path;
|
|
|
227 }
|
|
|
228 #endif /* S_IFLNK */
|
|
|
229 *new_path++ = '/';
|
|
|
230 }
|
|
|
231
|
|
|
232 /* Delete trailing slash but don't whomp a lone slash. */
|
|
|
233 if (new_path != resolved_path + 1 && new_path[-1] == '/')
|
|
|
234 new_path--;
|
|
|
235
|
|
|
236 /* Make sure it's null terminated. */
|
|
|
237 *new_path = '\0';
|
|
|
238 return resolved_path;
|
|
|
239 }
|
