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ffca4c22 | 1 | /* Return the canonical absolute name of a given file. |
f0007cad | 2 | Copyright (C) 1996-2012 Free Software Foundation, Inc. |
ffca4c22 AW |
3 | This file is part of the GNU C Library. |
4 | ||
5 | This program is free software: you can redistribute it and/or modify | |
6 | it under the terms of the GNU Lesser General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
8912421c | 18 | #ifndef _LIBC |
dd7d0148 | 19 | # define _GL_USE_STDLIB_ALLOC 1 |
8912421c LC |
20 | # include <config.h> |
21 | #endif | |
ffca4c22 | 22 | |
8912421c | 23 | #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC |
ffca4c22 | 24 | |
1cd4fffc LC |
25 | /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc |
26 | optimizes away the name == NULL test below. */ | |
27 | #define _GL_ARG_NONNULL(params) | |
28 | ||
ffca4c22 | 29 | /* Specification. */ |
ffca4c22 | 30 | #include <stdlib.h> |
ffca4c22 | 31 | |
8912421c LC |
32 | #include <alloca.h> |
33 | #include <string.h> | |
34 | #include <unistd.h> | |
ffca4c22 | 35 | #include <limits.h> |
ffca4c22 AW |
36 | #if HAVE_SYS_PARAM_H || defined _LIBC |
37 | # include <sys/param.h> | |
38 | #endif | |
ffca4c22 | 39 | #include <sys/stat.h> |
ffca4c22 | 40 | #include <errno.h> |
8912421c | 41 | #include <stddef.h> |
ffca4c22 AW |
42 | |
43 | #ifdef _LIBC | |
44 | # include <shlib-compat.h> | |
45 | #else | |
46 | # define SHLIB_COMPAT(lib, introduced, obsoleted) 0 | |
a927b6c1 | 47 | # define versioned_symbol(lib, local, symbol, version) extern int dummy |
ffca4c22 AW |
48 | # define compat_symbol(lib, local, symbol, version) |
49 | # define weak_alias(local, symbol) | |
50 | # define __canonicalize_file_name canonicalize_file_name | |
8912421c | 51 | # define __realpath realpath |
ffca4c22 AW |
52 | # include "pathmax.h" |
53 | # include "malloca.h" | |
54 | # if HAVE_GETCWD | |
9157d901 LC |
55 | # if IN_RELOCWRAPPER |
56 | /* When building the relocatable program wrapper, use the system's getcwd | |
57 | function, not the gnulib override, otherwise we would get a link error. | |
58 | */ | |
59 | # undef getcwd | |
60 | # endif | |
ffca4c22 AW |
61 | # ifdef VMS |
62 | /* We want the directory in Unix syntax, not in VMS syntax. */ | |
63 | # define __getcwd(buf, max) getcwd (buf, max, 0) | |
64 | # else | |
65 | # define __getcwd getcwd | |
66 | # endif | |
67 | # else | |
68 | # define __getcwd(buf, max) getwd (buf) | |
69 | # endif | |
70 | # define __readlink readlink | |
8912421c LC |
71 | # define __set_errno(e) errno = (e) |
72 | # ifndef MAXSYMLINKS | |
73 | # ifdef SYMLOOP_MAX | |
74 | # define MAXSYMLINKS SYMLOOP_MAX | |
75 | # else | |
76 | # define MAXSYMLINKS 20 | |
77 | # endif | |
ffca4c22 AW |
78 | # endif |
79 | #endif | |
80 | ||
8912421c LC |
81 | #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT |
82 | # define DOUBLE_SLASH_IS_DISTINCT_ROOT 0 | |
83 | #endif | |
84 | ||
85 | #if !FUNC_REALPATH_WORKS || defined _LIBC | |
ffca4c22 | 86 | /* Return the canonical absolute name of file NAME. A canonical name |
f0007cad | 87 | does not contain any ".", ".." components nor any repeated path |
ffca4c22 AW |
88 | separators ('/') or symlinks. All path components must exist. If |
89 | RESOLVED is null, the result is malloc'd; otherwise, if the | |
f0007cad | 90 | canonical name is PATH_MAX chars or more, returns null with 'errno' |
ffca4c22 AW |
91 | set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, |
92 | returns the name in RESOLVED. If the name cannot be resolved and | |
93 | RESOLVED is non-NULL, it contains the path of the first component | |
94 | that cannot be resolved. If the path can be resolved, RESOLVED | |
95 | holds the same value as the value returned. */ | |
96 | ||
97 | char * | |
98 | __realpath (const char *name, char *resolved) | |
99 | { | |
100 | char *rpath, *dest, *extra_buf = NULL; | |
101 | const char *start, *end, *rpath_limit; | |
102 | long int path_max; | |
ffca4c22 | 103 | int num_links = 0; |
ffca4c22 AW |
104 | |
105 | if (name == NULL) | |
106 | { | |
107 | /* As per Single Unix Specification V2 we must return an error if | |
1cd4fffc LC |
108 | either parameter is a null pointer. We extend this to allow |
109 | the RESOLVED parameter to be NULL in case the we are expected to | |
110 | allocate the room for the return value. */ | |
ffca4c22 AW |
111 | __set_errno (EINVAL); |
112 | return NULL; | |
113 | } | |
114 | ||
115 | if (name[0] == '\0') | |
116 | { | |
117 | /* As per Single Unix Specification V2 we must return an error if | |
1cd4fffc | 118 | the name argument points to an empty string. */ |
ffca4c22 AW |
119 | __set_errno (ENOENT); |
120 | return NULL; | |
121 | } | |
122 | ||
123 | #ifdef PATH_MAX | |
124 | path_max = PATH_MAX; | |
125 | #else | |
126 | path_max = pathconf (name, _PC_PATH_MAX); | |
127 | if (path_max <= 0) | |
35428fb6 | 128 | path_max = 8192; |
ffca4c22 AW |
129 | #endif |
130 | ||
131 | if (resolved == NULL) | |
132 | { | |
133 | rpath = malloc (path_max); | |
134 | if (rpath == NULL) | |
1cd4fffc LC |
135 | { |
136 | /* It's easier to set errno to ENOMEM than to rely on the | |
137 | 'malloc-posix' gnulib module. */ | |
138 | errno = ENOMEM; | |
139 | return NULL; | |
140 | } | |
ffca4c22 AW |
141 | } |
142 | else | |
143 | rpath = resolved; | |
144 | rpath_limit = rpath + path_max; | |
145 | ||
146 | if (name[0] != '/') | |
147 | { | |
148 | if (!__getcwd (rpath, path_max)) | |
1cd4fffc LC |
149 | { |
150 | rpath[0] = '\0'; | |
151 | goto error; | |
152 | } | |
ffca4c22 AW |
153 | dest = strchr (rpath, '\0'); |
154 | } | |
155 | else | |
156 | { | |
157 | rpath[0] = '/'; | |
158 | dest = rpath + 1; | |
8912421c | 159 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/') |
1cd4fffc | 160 | *dest++ = '/'; |
ffca4c22 AW |
161 | } |
162 | ||
163 | for (start = end = name; *start; start = end) | |
164 | { | |
165 | #ifdef _LIBC | |
166 | struct stat64 st; | |
167 | #else | |
168 | struct stat st; | |
169 | #endif | |
8912421c | 170 | int n; |
ffca4c22 AW |
171 | |
172 | /* Skip sequence of multiple path-separators. */ | |
173 | while (*start == '/') | |
1cd4fffc | 174 | ++start; |
ffca4c22 AW |
175 | |
176 | /* Find end of path component. */ | |
177 | for (end = start; *end && *end != '/'; ++end) | |
1cd4fffc | 178 | /* Nothing. */; |
ffca4c22 AW |
179 | |
180 | if (end - start == 0) | |
1cd4fffc | 181 | break; |
ffca4c22 | 182 | else if (end - start == 1 && start[0] == '.') |
1cd4fffc | 183 | /* nothing */; |
ffca4c22 | 184 | else if (end - start == 2 && start[0] == '.' && start[1] == '.') |
1cd4fffc LC |
185 | { |
186 | /* Back up to previous component, ignore if at root already. */ | |
187 | if (dest > rpath + 1) | |
188 | while ((--dest)[-1] != '/'); | |
189 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 | |
190 | && *dest == '/') | |
191 | dest++; | |
192 | } | |
ffca4c22 | 193 | else |
1cd4fffc LC |
194 | { |
195 | size_t new_size; | |
196 | ||
197 | if (dest[-1] != '/') | |
198 | *dest++ = '/'; | |
199 | ||
200 | if (dest + (end - start) >= rpath_limit) | |
201 | { | |
202 | ptrdiff_t dest_offset = dest - rpath; | |
203 | char *new_rpath; | |
204 | ||
205 | if (resolved) | |
206 | { | |
207 | __set_errno (ENAMETOOLONG); | |
208 | if (dest > rpath + 1) | |
209 | dest--; | |
210 | *dest = '\0'; | |
211 | goto error; | |
212 | } | |
213 | new_size = rpath_limit - rpath; | |
214 | if (end - start + 1 > path_max) | |
215 | new_size += end - start + 1; | |
216 | else | |
217 | new_size += path_max; | |
218 | new_rpath = (char *) realloc (rpath, new_size); | |
219 | if (new_rpath == NULL) | |
220 | { | |
221 | /* It's easier to set errno to ENOMEM than to rely on the | |
222 | 'realloc-posix' gnulib module. */ | |
223 | errno = ENOMEM; | |
224 | goto error; | |
225 | } | |
226 | rpath = new_rpath; | |
227 | rpath_limit = rpath + new_size; | |
228 | ||
229 | dest = rpath + dest_offset; | |
230 | } | |
ffca4c22 AW |
231 | |
232 | #ifdef _LIBC | |
1cd4fffc | 233 | dest = __mempcpy (dest, start, end - start); |
ffca4c22 | 234 | #else |
1cd4fffc LC |
235 | memcpy (dest, start, end - start); |
236 | dest += end - start; | |
ffca4c22 | 237 | #endif |
1cd4fffc | 238 | *dest = '\0'; |
ffca4c22 AW |
239 | |
240 | #ifdef _LIBC | |
1cd4fffc | 241 | if (__lxstat64 (_STAT_VER, rpath, &st) < 0) |
ffca4c22 | 242 | #else |
1cd4fffc | 243 | if (lstat (rpath, &st) < 0) |
ffca4c22 | 244 | #endif |
1cd4fffc LC |
245 | goto error; |
246 | ||
247 | if (S_ISLNK (st.st_mode)) | |
248 | { | |
249 | char *buf; | |
250 | size_t len; | |
251 | ||
252 | if (++num_links > MAXSYMLINKS) | |
253 | { | |
254 | __set_errno (ELOOP); | |
255 | goto error; | |
256 | } | |
257 | ||
258 | buf = malloca (path_max); | |
259 | if (!buf) | |
260 | { | |
261 | errno = ENOMEM; | |
262 | goto error; | |
263 | } | |
264 | ||
265 | n = __readlink (rpath, buf, path_max - 1); | |
266 | if (n < 0) | |
267 | { | |
268 | int saved_errno = errno; | |
269 | freea (buf); | |
270 | errno = saved_errno; | |
271 | goto error; | |
272 | } | |
273 | buf[n] = '\0'; | |
274 | ||
275 | if (!extra_buf) | |
276 | { | |
277 | extra_buf = malloca (path_max); | |
278 | if (!extra_buf) | |
279 | { | |
280 | freea (buf); | |
281 | errno = ENOMEM; | |
282 | goto error; | |
283 | } | |
284 | } | |
285 | ||
286 | len = strlen (end); | |
287 | if ((long int) (n + len) >= path_max) | |
288 | { | |
289 | freea (buf); | |
290 | __set_errno (ENAMETOOLONG); | |
291 | goto error; | |
292 | } | |
293 | ||
294 | /* Careful here, end may be a pointer into extra_buf... */ | |
295 | memmove (&extra_buf[n], end, len + 1); | |
296 | name = end = memcpy (extra_buf, buf, n); | |
297 | ||
298 | if (buf[0] == '/') | |
299 | { | |
300 | dest = rpath + 1; /* It's an absolute symlink */ | |
301 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && buf[1] == '/') | |
302 | *dest++ = '/'; | |
303 | } | |
304 | else | |
305 | { | |
306 | /* Back up to previous component, ignore if at root | |
307 | already: */ | |
308 | if (dest > rpath + 1) | |
309 | while ((--dest)[-1] != '/'); | |
310 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 | |
311 | && *dest == '/') | |
312 | dest++; | |
313 | } | |
314 | } | |
315 | else if (!S_ISDIR (st.st_mode) && *end != '\0') | |
316 | { | |
317 | __set_errno (ENOTDIR); | |
318 | goto error; | |
319 | } | |
320 | } | |
ffca4c22 AW |
321 | } |
322 | if (dest > rpath + 1 && dest[-1] == '/') | |
323 | --dest; | |
8912421c LC |
324 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && *dest == '/') |
325 | dest++; | |
ffca4c22 AW |
326 | *dest = '\0'; |
327 | ||
328 | if (extra_buf) | |
329 | freea (extra_buf); | |
330 | ||
8912421c | 331 | return rpath; |
ffca4c22 AW |
332 | |
333 | error: | |
334 | { | |
335 | int saved_errno = errno; | |
336 | if (extra_buf) | |
337 | freea (extra_buf); | |
8912421c | 338 | if (resolved == NULL) |
ffca4c22 AW |
339 | free (rpath); |
340 | errno = saved_errno; | |
341 | } | |
342 | return NULL; | |
343 | } | |
ffca4c22 | 344 | versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); |
8912421c | 345 | #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */ |
ffca4c22 AW |
346 | |
347 | ||
348 | #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) | |
349 | char * | |
8912421c | 350 | attribute_compat_text_section |
ffca4c22 AW |
351 | __old_realpath (const char *name, char *resolved) |
352 | { | |
353 | if (resolved == NULL) | |
354 | { | |
355 | __set_errno (EINVAL); | |
356 | return NULL; | |
357 | } | |
358 | ||
359 | return __realpath (name, resolved); | |
360 | } | |
361 | compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); | |
362 | #endif | |
363 | ||
364 | ||
365 | char * | |
366 | __canonicalize_file_name (const char *name) | |
367 | { | |
368 | return __realpath (name, NULL); | |
369 | } | |
370 | weak_alias (__canonicalize_file_name, canonicalize_file_name) | |
371 | ||
372 | #else | |
373 | ||
374 | /* This declaration is solely to ensure that after preprocessing | |
375 | this file is never empty. */ | |
376 | typedef int dummy; | |
377 | ||
378 | #endif |