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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; | |
005de2e8 LC |
159 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
160 | { | |
161 | if (name[1] == '/' && name[2] != '/') | |
162 | *dest++ = '/'; | |
163 | *dest = '\0'; | |
164 | } | |
ffca4c22 AW |
165 | } |
166 | ||
167 | for (start = end = name; *start; start = end) | |
168 | { | |
169 | #ifdef _LIBC | |
170 | struct stat64 st; | |
171 | #else | |
172 | struct stat st; | |
173 | #endif | |
8912421c | 174 | int n; |
ffca4c22 AW |
175 | |
176 | /* Skip sequence of multiple path-separators. */ | |
177 | while (*start == '/') | |
1cd4fffc | 178 | ++start; |
ffca4c22 AW |
179 | |
180 | /* Find end of path component. */ | |
181 | for (end = start; *end && *end != '/'; ++end) | |
1cd4fffc | 182 | /* Nothing. */; |
ffca4c22 AW |
183 | |
184 | if (end - start == 0) | |
1cd4fffc | 185 | break; |
ffca4c22 | 186 | else if (end - start == 1 && start[0] == '.') |
1cd4fffc | 187 | /* nothing */; |
ffca4c22 | 188 | else if (end - start == 2 && start[0] == '.' && start[1] == '.') |
1cd4fffc LC |
189 | { |
190 | /* Back up to previous component, ignore if at root already. */ | |
191 | if (dest > rpath + 1) | |
192 | while ((--dest)[-1] != '/'); | |
193 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 | |
005de2e8 | 194 | && *dest == '/' && dest[1] != '/') |
1cd4fffc LC |
195 | dest++; |
196 | } | |
ffca4c22 | 197 | else |
1cd4fffc LC |
198 | { |
199 | size_t new_size; | |
200 | ||
201 | if (dest[-1] != '/') | |
202 | *dest++ = '/'; | |
203 | ||
204 | if (dest + (end - start) >= rpath_limit) | |
205 | { | |
206 | ptrdiff_t dest_offset = dest - rpath; | |
207 | char *new_rpath; | |
208 | ||
209 | if (resolved) | |
210 | { | |
211 | __set_errno (ENAMETOOLONG); | |
212 | if (dest > rpath + 1) | |
213 | dest--; | |
214 | *dest = '\0'; | |
215 | goto error; | |
216 | } | |
217 | new_size = rpath_limit - rpath; | |
218 | if (end - start + 1 > path_max) | |
219 | new_size += end - start + 1; | |
220 | else | |
221 | new_size += path_max; | |
222 | new_rpath = (char *) realloc (rpath, new_size); | |
223 | if (new_rpath == NULL) | |
224 | { | |
225 | /* It's easier to set errno to ENOMEM than to rely on the | |
226 | 'realloc-posix' gnulib module. */ | |
227 | errno = ENOMEM; | |
228 | goto error; | |
229 | } | |
230 | rpath = new_rpath; | |
231 | rpath_limit = rpath + new_size; | |
232 | ||
233 | dest = rpath + dest_offset; | |
234 | } | |
ffca4c22 AW |
235 | |
236 | #ifdef _LIBC | |
1cd4fffc | 237 | dest = __mempcpy (dest, start, end - start); |
ffca4c22 | 238 | #else |
1cd4fffc LC |
239 | memcpy (dest, start, end - start); |
240 | dest += end - start; | |
ffca4c22 | 241 | #endif |
1cd4fffc | 242 | *dest = '\0'; |
ffca4c22 AW |
243 | |
244 | #ifdef _LIBC | |
1cd4fffc | 245 | if (__lxstat64 (_STAT_VER, rpath, &st) < 0) |
ffca4c22 | 246 | #else |
1cd4fffc | 247 | if (lstat (rpath, &st) < 0) |
ffca4c22 | 248 | #endif |
1cd4fffc LC |
249 | goto error; |
250 | ||
251 | if (S_ISLNK (st.st_mode)) | |
252 | { | |
253 | char *buf; | |
254 | size_t len; | |
255 | ||
256 | if (++num_links > MAXSYMLINKS) | |
257 | { | |
258 | __set_errno (ELOOP); | |
259 | goto error; | |
260 | } | |
261 | ||
262 | buf = malloca (path_max); | |
263 | if (!buf) | |
264 | { | |
265 | errno = ENOMEM; | |
266 | goto error; | |
267 | } | |
268 | ||
269 | n = __readlink (rpath, buf, path_max - 1); | |
270 | if (n < 0) | |
271 | { | |
272 | int saved_errno = errno; | |
273 | freea (buf); | |
274 | errno = saved_errno; | |
275 | goto error; | |
276 | } | |
277 | buf[n] = '\0'; | |
278 | ||
279 | if (!extra_buf) | |
280 | { | |
281 | extra_buf = malloca (path_max); | |
282 | if (!extra_buf) | |
283 | { | |
284 | freea (buf); | |
285 | errno = ENOMEM; | |
286 | goto error; | |
287 | } | |
288 | } | |
289 | ||
290 | len = strlen (end); | |
291 | if ((long int) (n + len) >= path_max) | |
292 | { | |
293 | freea (buf); | |
294 | __set_errno (ENAMETOOLONG); | |
295 | goto error; | |
296 | } | |
297 | ||
298 | /* Careful here, end may be a pointer into extra_buf... */ | |
299 | memmove (&extra_buf[n], end, len + 1); | |
300 | name = end = memcpy (extra_buf, buf, n); | |
301 | ||
302 | if (buf[0] == '/') | |
303 | { | |
304 | dest = rpath + 1; /* It's an absolute symlink */ | |
005de2e8 LC |
305 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
306 | { | |
307 | if (buf[1] == '/' && buf[2] != '/') | |
308 | *dest++ = '/'; | |
309 | *dest = '\0'; | |
310 | } | |
1cd4fffc LC |
311 | } |
312 | else | |
313 | { | |
314 | /* Back up to previous component, ignore if at root | |
315 | already: */ | |
316 | if (dest > rpath + 1) | |
317 | while ((--dest)[-1] != '/'); | |
318 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 | |
005de2e8 | 319 | && *dest == '/' && dest[1] != '/') |
1cd4fffc LC |
320 | dest++; |
321 | } | |
322 | } | |
323 | else if (!S_ISDIR (st.st_mode) && *end != '\0') | |
324 | { | |
325 | __set_errno (ENOTDIR); | |
326 | goto error; | |
327 | } | |
328 | } | |
ffca4c22 AW |
329 | } |
330 | if (dest > rpath + 1 && dest[-1] == '/') | |
331 | --dest; | |
005de2e8 LC |
332 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 |
333 | && *dest == '/' && dest[1] != '/') | |
8912421c | 334 | dest++; |
ffca4c22 AW |
335 | *dest = '\0'; |
336 | ||
337 | if (extra_buf) | |
338 | freea (extra_buf); | |
339 | ||
8912421c | 340 | return rpath; |
ffca4c22 AW |
341 | |
342 | error: | |
343 | { | |
344 | int saved_errno = errno; | |
345 | if (extra_buf) | |
346 | freea (extra_buf); | |
8912421c | 347 | if (resolved == NULL) |
ffca4c22 AW |
348 | free (rpath); |
349 | errno = saved_errno; | |
350 | } | |
351 | return NULL; | |
352 | } | |
ffca4c22 | 353 | versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); |
8912421c | 354 | #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */ |
ffca4c22 AW |
355 | |
356 | ||
357 | #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) | |
358 | char * | |
8912421c | 359 | attribute_compat_text_section |
ffca4c22 AW |
360 | __old_realpath (const char *name, char *resolved) |
361 | { | |
362 | if (resolved == NULL) | |
363 | { | |
364 | __set_errno (EINVAL); | |
365 | return NULL; | |
366 | } | |
367 | ||
368 | return __realpath (name, resolved); | |
369 | } | |
370 | compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); | |
371 | #endif | |
372 | ||
373 | ||
374 | char * | |
375 | __canonicalize_file_name (const char *name) | |
376 | { | |
377 | return __realpath (name, NULL); | |
378 | } | |
379 | weak_alias (__canonicalize_file_name, canonicalize_file_name) | |
380 | ||
381 | #else | |
382 | ||
383 | /* This declaration is solely to ensure that after preprocessing | |
384 | this file is never empty. */ | |
385 | typedef int dummy; | |
386 | ||
387 | #endif |