1 | /* Copyright (C) 1991-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ |
17 | |
18 | /* Wants: |
19 | AC_STDC_HEADERS |
20 | AC_DIR_HEADER |
21 | AC_UNISTD_H |
22 | AC_MEMORY_H |
23 | AC_CONST |
24 | AC_ALLOCA |
25 | */ |
26 | |
27 | /* AIX requires this to be the first thing in the file. */ |
28 | #if defined _AIX && !defined __GNUC__ |
29 | #pragma alloca |
30 | #endif |
31 | |
32 | #ifdef HAVE_CONFIG_H |
33 | # include "config.h" |
34 | #endif |
35 | |
36 | #include <errno.h> |
37 | #include <fcntl.h> |
38 | #include <sys/types.h> |
39 | #include <sys/stat.h> |
40 | |
41 | #ifdef STDC_HEADERS |
42 | # include <stddef.h> |
43 | #endif |
44 | |
45 | #if !defined __GNU_LIBRARY__ && !defined STDC_HEADERS |
46 | extern int errno; |
47 | #endif |
48 | #ifndef __set_errno |
49 | # define __set_errno(val) errno = (val) |
50 | #endif |
51 | |
52 | #ifndef NULL |
53 | # define NULL 0 |
54 | #endif |
55 | |
56 | #if defined USGr3 && !defined DIRENT |
57 | # define DIRENT |
58 | #endif /* USGr3 */ |
59 | #if defined Xenix && !defined SYSNDIR |
60 | # define SYSNDIR |
61 | #endif /* Xenix */ |
62 | |
63 | #if defined POSIX || defined DIRENT || defined __GNU_LIBRARY__ |
64 | # include <dirent.h> |
65 | # ifndef __GNU_LIBRARY__ |
66 | # define D_NAMLEN(d) strlen((d)->d_name) |
67 | # else |
68 | # define HAVE_D_NAMLEN |
69 | # define D_NAMLEN(d) ((d)->d_namlen) |
70 | # endif |
71 | #else /* not POSIX or DIRENT */ |
72 | # define dirent direct |
73 | # define D_NAMLEN(d) ((d)->d_namlen) |
74 | # define HAVE_D_NAMLEN |
75 | # if defined USG && !defined sgi |
76 | # if defined SYSNDIR |
77 | # include <sys/ndir.h> |
78 | # else /* Not SYSNDIR */ |
79 | # include "ndir.h" |
80 | # endif /* SYSNDIR */ |
81 | # else /* not USG */ |
82 | # include <sys/dir.h> |
83 | # endif /* USG */ |
84 | #endif /* POSIX or DIRENT or __GNU_LIBRARY__ */ |
85 | |
86 | #if defined HAVE_UNISTD_H || defined __GNU_LIBRARY__ |
87 | # include <unistd.h> |
88 | #endif |
89 | |
90 | #if defined STDC_HEADERS || defined __GNU_LIBRARY__ || defined POSIX |
91 | # include <stdlib.h> |
92 | # include <string.h> |
93 | # define ANSI_STRING |
94 | #else /* No standard headers. */ |
95 | |
96 | # ifdef USG |
97 | |
98 | # include <string.h> |
99 | # ifdef NEED_MEMORY_H |
100 | # include <memory.h> |
101 | # endif |
102 | # define ANSI_STRING |
103 | |
104 | # else /* Not USG. */ |
105 | |
106 | # ifdef NeXT |
107 | |
108 | # include <string.h> |
109 | |
110 | # else /* Not NeXT. */ |
111 | |
112 | # include <strings.h> |
113 | |
114 | # ifndef bcmp |
115 | extern int bcmp (); |
116 | # endif |
117 | # ifndef bzero |
118 | extern void bzero (); |
119 | # endif |
120 | # ifndef bcopy |
121 | extern void bcopy (); |
122 | # endif |
123 | |
124 | # endif /* NeXT. */ |
125 | |
126 | # endif /* USG. */ |
127 | |
128 | extern char *malloc (), *realloc (); |
129 | extern void free (); |
130 | |
131 | #endif /* Standard headers. */ |
132 | |
133 | #ifndef ANSI_STRING |
134 | # define memcpy(d, s, n) bcopy((s), (d), (n)) |
135 | # define memmove memcpy |
136 | #endif /* Not ANSI_STRING. */ |
137 | |
138 | #ifndef MAX |
139 | # define MAX(a, b) ((a) < (b) ? (b) : (a)) |
140 | #endif |
141 | |
142 | #ifdef _LIBC |
143 | # ifndef mempcpy |
144 | # define mempcpy __mempcpy |
145 | # endif |
146 | # define HAVE_MEMPCPY 1 |
147 | #endif |
148 | |
149 | #if !defined __alloca && !defined __GNU_LIBRARY__ |
150 | |
151 | # ifdef __GNUC__ |
152 | # undef alloca |
153 | # define alloca(n) __builtin_alloca (n) |
154 | # else /* Not GCC. */ |
155 | # if defined sparc || defined HAVE_ALLOCA_H |
156 | # include <alloca.h> |
157 | # else /* Not sparc or HAVE_ALLOCA_H. */ |
158 | # ifndef _AIX |
159 | extern char *alloca (); |
160 | # endif /* Not _AIX. */ |
161 | # endif /* sparc or HAVE_ALLOCA_H. */ |
162 | # endif /* GCC. */ |
163 | |
164 | # define __alloca alloca |
165 | |
166 | #endif |
167 | |
168 | #if defined HAVE_LIMITS_H || defined STDC_HEADERS || defined __GNU_LIBRARY__ |
169 | # include <limits.h> |
170 | #else |
171 | # include <sys/param.h> |
172 | #endif |
173 | |
174 | #if defined _LIBC |
175 | # include <not-cancel.h> |
176 | # include <kernel-features.h> |
177 | #else |
178 | # define openat64_not_cancel_3(dfd, name, mode) openat64 (dfd, name, mode) |
179 | # define close_not_cancel_no_status(fd) close (fd) |
180 | #endif |
181 | |
182 | #ifndef PATH_MAX |
183 | # ifdef MAXPATHLEN |
184 | # define PATH_MAX MAXPATHLEN |
185 | # else |
186 | # define PATH_MAX 1024 |
187 | # endif |
188 | #endif |
189 | |
190 | #if !defined STDC_HEADERS && !defined __GNU_LIBRARY__ |
191 | # undef size_t |
192 | # define size_t unsigned int |
193 | #endif |
194 | |
195 | #ifndef __GNU_LIBRARY__ |
196 | # define __lstat64 stat64 |
197 | #endif |
198 | |
199 | #ifndef _LIBC |
200 | # define __rewinddir rewinddir |
201 | #endif |
202 | |
203 | #ifndef _LIBC |
204 | # define __getcwd getcwd |
205 | #endif |
206 | |
207 | #ifndef GETCWD_RETURN_TYPE |
208 | # define GETCWD_RETURN_TYPE char * |
209 | #endif |
210 | |
211 | #ifdef __ASSUME_ATFCTS |
212 | # define __have_atfcts 1 |
213 | #elif IS_IN (rtld) |
214 | static int __rtld_have_atfcts; |
215 | # define __have_atfcts __rtld_have_atfcts |
216 | #endif |
217 | |
218 | /* Get the pathname of the current working directory, and put it in SIZE |
219 | bytes of BUF. Returns NULL if the directory couldn't be determined or |
220 | SIZE was too small. If successful, returns BUF. In GNU, if BUF is |
221 | NULL, an array is allocated with `malloc'; the array is SIZE bytes long, |
222 | unless SIZE == 0, in which case it is as big as necessary. */ |
223 | |
224 | GETCWD_RETURN_TYPE |
225 | __getcwd (char *buf, size_t size) |
226 | { |
227 | #ifndef __ASSUME_ATFCTS |
228 | static const char dots[] |
229 | = "../../../../../../../../../../../../../../../../../../../../../../../\ |
230 | ../../../../../../../../../../../../../../../../../../../../../../../../../../\ |
231 | ../../../../../../../../../../../../../../../../../../../../../../../../../.." ; |
232 | const char *dotp = &dots[sizeof (dots)]; |
233 | const char *dotlist = dots; |
234 | size_t dotsize = sizeof (dots) - 1; |
235 | #endif |
236 | int prev_errno = errno; |
237 | DIR *dirstream = NULL; |
238 | bool fd_needs_closing = false; |
239 | int fd = AT_FDCWD; |
240 | |
241 | char *path; |
242 | #ifndef NO_ALLOCATION |
243 | size_t allocated = size; |
244 | if (size == 0) |
245 | { |
246 | if (buf != NULL) |
247 | { |
248 | __set_errno (EINVAL); |
249 | return NULL; |
250 | } |
251 | |
252 | allocated = PATH_MAX + 1; |
253 | } |
254 | |
255 | if (buf == NULL) |
256 | { |
257 | path = malloc (allocated); |
258 | if (path == NULL) |
259 | return NULL; |
260 | } |
261 | else |
262 | #else |
263 | # define allocated size |
264 | #endif |
265 | path = buf; |
266 | |
267 | char *pathp = path + allocated; |
268 | *--pathp = '\0'; |
269 | |
270 | struct stat64 st; |
271 | if (__lstat64 ("." , &st) < 0) |
272 | goto lose; |
273 | dev_t thisdev = st.st_dev; |
274 | ino_t thisino = st.st_ino; |
275 | |
276 | if (__lstat64 ("/" , &st) < 0) |
277 | goto lose; |
278 | dev_t rootdev = st.st_dev; |
279 | ino_t rootino = st.st_ino; |
280 | |
281 | while (!(thisdev == rootdev && thisino == rootino)) |
282 | { |
283 | if (__have_atfcts >= 0) |
284 | { |
285 | int mode = O_RDONLY; |
286 | #ifdef O_CLOEXEC |
287 | mode |= O_CLOEXEC; |
288 | #endif |
289 | fd = openat64_not_cancel_3 (fd, ".." , mode); |
290 | } |
291 | else |
292 | fd = -1; |
293 | if (fd >= 0) |
294 | { |
295 | fd_needs_closing = true; |
296 | if (__fstat64 (fd, &st) < 0) |
297 | goto lose; |
298 | } |
299 | #ifndef __ASSUME_ATFCTS |
300 | else if (errno == ENOSYS) |
301 | { |
302 | __have_atfcts = -1; |
303 | |
304 | /* Look at the parent directory. */ |
305 | if (dotp == dotlist) |
306 | { |
307 | # ifdef NO_ALLOCATION |
308 | __set_errno (ENOMEM); |
309 | goto lose; |
310 | # else |
311 | /* My, what a deep directory tree you have, Grandma. */ |
312 | char *new; |
313 | if (dotlist == dots) |
314 | { |
315 | new = malloc (dotsize * 2 + 1); |
316 | if (new == NULL) |
317 | goto lose; |
318 | # ifdef HAVE_MEMPCPY |
319 | dotp = mempcpy (new, dots, dotsize); |
320 | # else |
321 | memcpy (new, dots, dotsize); |
322 | dotp = &new[dotsize]; |
323 | # endif |
324 | } |
325 | else |
326 | { |
327 | new = realloc ((__ptr_t) dotlist, dotsize * 2 + 1); |
328 | if (new == NULL) |
329 | goto lose; |
330 | dotp = &new[dotsize]; |
331 | } |
332 | # ifdef HAVE_MEMPCPY |
333 | *((char *) mempcpy ((char *) dotp, new, dotsize)) = '\0'; |
334 | dotsize *= 2; |
335 | # else |
336 | memcpy ((char *) dotp, new, dotsize); |
337 | dotsize *= 2; |
338 | new[dotsize] = '\0'; |
339 | # endif |
340 | dotlist = new; |
341 | # endif |
342 | } |
343 | |
344 | dotp -= 3; |
345 | |
346 | /* Figure out if this directory is a mount point. */ |
347 | if (__lstat64 (dotp, &st) < 0) |
348 | goto lose; |
349 | } |
350 | #endif |
351 | else |
352 | goto lose; |
353 | |
354 | if (dirstream && __closedir (dirstream) != 0) |
355 | { |
356 | dirstream = NULL; |
357 | goto lose; |
358 | } |
359 | |
360 | dev_t dotdev = st.st_dev; |
361 | ino_t dotino = st.st_ino; |
362 | bool mount_point = dotdev != thisdev; |
363 | |
364 | /* Search for the last directory. */ |
365 | if (__have_atfcts >= 0) |
366 | dirstream = __fdopendir (fd); |
367 | #ifndef __ASSUME_ATFCTS |
368 | else |
369 | dirstream = __opendir (dotp); |
370 | #endif |
371 | if (dirstream == NULL) |
372 | goto lose; |
373 | fd_needs_closing = false; |
374 | |
375 | struct dirent *d; |
376 | bool use_d_ino = true; |
377 | while (1) |
378 | { |
379 | /* Clear errno to distinguish EOF from error if readdir returns |
380 | NULL. */ |
381 | __set_errno (0); |
382 | d = __readdir (dirstream); |
383 | if (d == NULL) |
384 | { |
385 | if (errno == 0) |
386 | { |
387 | /* When we've iterated through all directory entries |
388 | without finding one with a matching d_ino, rewind the |
389 | stream and consider each name again, but this time, using |
390 | lstat64. This is necessary in a chroot on at least one |
391 | system. */ |
392 | if (use_d_ino) |
393 | { |
394 | use_d_ino = false; |
395 | __rewinddir (dirstream); |
396 | continue; |
397 | } |
398 | |
399 | /* EOF on dirstream, which means that the current directory |
400 | has been removed. */ |
401 | __set_errno (ENOENT); |
402 | } |
403 | goto lose; |
404 | } |
405 | |
406 | #ifdef _DIRENT_HAVE_D_TYPE |
407 | if (d->d_type != DT_DIR && d->d_type != DT_UNKNOWN) |
408 | continue; |
409 | #endif |
410 | if (d->d_name[0] == '.' |
411 | && (d->d_name[1] == '\0' |
412 | || (d->d_name[1] == '.' && d->d_name[2] == '\0'))) |
413 | continue; |
414 | if (use_d_ino && !mount_point && (ino_t) d->d_ino != thisino) |
415 | continue; |
416 | |
417 | if (__have_atfcts >= 0) |
418 | { |
419 | /* We don't fail here if we cannot stat64() a directory entry. |
420 | This can happen when (network) filesystems fail. If this |
421 | entry is in fact the one we are looking for we will find |
422 | out soon as we reach the end of the directory without |
423 | having found anything. */ |
424 | if (__fstatat64 (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) |
425 | continue; |
426 | } |
427 | #ifndef __ASSUME_ATFCTS |
428 | else |
429 | { |
430 | char name[dotlist + dotsize - dotp + 1 + _D_ALLOC_NAMLEN (d)]; |
431 | # ifdef HAVE_MEMPCPY |
432 | char *tmp = mempcpy (name, dotp, dotlist + dotsize - dotp); |
433 | *tmp++ = '/'; |
434 | strcpy (tmp, d->d_name); |
435 | # else |
436 | memcpy (name, dotp, dotlist + dotsize - dotp); |
437 | name[dotlist + dotsize - dotp] = '/'; |
438 | strcpy (&name[dotlist + dotsize - dotp + 1], d->d_name); |
439 | # endif |
440 | /* We don't fail here if we cannot stat64() a directory entry. |
441 | This can happen when (network) filesystems fail. If this |
442 | entry is in fact the one we are looking for we will find |
443 | out soon as we reach the end of the directory without |
444 | having found anything. */ |
445 | if (__lstat64 (name, &st) < 0) |
446 | continue; |
447 | } |
448 | #endif |
449 | if (S_ISDIR (st.st_mode) |
450 | && st.st_dev == thisdev && st.st_ino == thisino) |
451 | break; |
452 | } |
453 | |
454 | size_t namlen = _D_EXACT_NAMLEN (d); |
455 | |
456 | if ((size_t) (pathp - path) <= namlen) |
457 | { |
458 | #ifndef NO_ALLOCATION |
459 | if (size == 0) |
460 | { |
461 | size_t oldsize = allocated; |
462 | |
463 | allocated = 2 * MAX (allocated, namlen); |
464 | char *tmp = realloc (path, allocated); |
465 | if (tmp == NULL) |
466 | goto lose; |
467 | |
468 | /* Move current contents up to the end of the buffer. |
469 | This is guaranteed to be non-overlapping. */ |
470 | pathp = memcpy (tmp + allocated - (path + oldsize - pathp), |
471 | tmp + (pathp - path), |
472 | path + oldsize - pathp); |
473 | path = tmp; |
474 | } |
475 | else |
476 | #endif |
477 | { |
478 | __set_errno (ERANGE); |
479 | goto lose; |
480 | } |
481 | } |
482 | pathp -= namlen; |
483 | (void) memcpy (pathp, d->d_name, namlen); |
484 | *--pathp = '/'; |
485 | |
486 | thisdev = dotdev; |
487 | thisino = dotino; |
488 | } |
489 | |
490 | if (dirstream != NULL && __closedir (dirstream) != 0) |
491 | { |
492 | dirstream = NULL; |
493 | goto lose; |
494 | } |
495 | |
496 | if (pathp == &path[allocated - 1]) |
497 | *--pathp = '/'; |
498 | |
499 | #ifndef __ASSUME_ATFCTS |
500 | if (dotlist != dots) |
501 | free ((__ptr_t) dotlist); |
502 | #endif |
503 | |
504 | size_t used = path + allocated - pathp; |
505 | memmove (path, pathp, used); |
506 | |
507 | if (size == 0) |
508 | /* Ensure that the buffer is only as large as necessary. */ |
509 | buf = realloc (path, used); |
510 | |
511 | if (buf == NULL) |
512 | /* Either buf was NULL all along, or `realloc' failed but |
513 | we still have the original string. */ |
514 | buf = path; |
515 | |
516 | /* Restore errno on successful return. */ |
517 | __set_errno (prev_errno); |
518 | |
519 | return buf; |
520 | |
521 | lose:; |
522 | int save_errno = errno; |
523 | #ifndef __ASSUME_ATFCTS |
524 | if (dotlist != dots) |
525 | free ((__ptr_t) dotlist); |
526 | #endif |
527 | if (dirstream != NULL) |
528 | __closedir (dirstream); |
529 | if (fd_needs_closing) |
530 | close_not_cancel_no_status (fd); |
531 | #ifndef NO_ALLOCATION |
532 | if (buf == NULL) |
533 | free (path); |
534 | #endif |
535 | __set_errno (save_errno); |
536 | return NULL; |
537 | } |
538 | |
539 | #if defined _LIBC && !defined __getcwd |
540 | weak_alias (__getcwd, getcwd) |
541 | #endif |
542 | |