1 /* Copyright (C) 1991,92,93,94,95,96,97,98,99,2004,2005,2006 Free Software
3 This file is part of the GNU C Library.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
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 General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
28 #include <sys/types.h>
33 #include <fcntl.h> /* For AT_FDCWD on Solaris 9. */
36 # define __set_errno(val) (errno = (val))
39 #if HAVE_DIRENT_H || _LIBC
41 # ifndef _D_EXACT_NAMLEN
42 # define _D_EXACT_NAMLEN(d) strlen ((d)->d_name)
45 # define dirent direct
47 # include <sys/ndir.h>
56 #ifndef _D_EXACT_NAMLEN
57 # define _D_EXACT_NAMLEN(d) ((d)->d_namlen)
59 #ifndef _D_ALLOC_NAMLEN
60 # define _D_ALLOC_NAMLEN(d) (_D_EXACT_NAMLEN (d) + 1)
69 # define mempcpy __mempcpy
77 /* Work around a bug in Solaris 9 and 10: AT_FDCWD is positive. Its
78 value exceeds INT_MAX, so its use as an int doesn't conform to the
79 C standard, and GCC and Sun C complain in some cases. */
80 #if 0 < AT_FDCWD && AT_FDCWD == 0xffd19553
82 # define AT_FDCWD (-3041965)
86 # define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
88 # define is_ENAMETOOLONG(x) 0
92 # define MAX(a, b) ((a) < (b) ? (b) : (a))
95 # define MIN(a, b) ((a) < (b) ? (a) : (b))
100 # define PATH_MAX MAXPATHLEN
102 # define PATH_MAX 1024
107 # define MATCHING_INO(dp, ino) ((dp)->d_ino == (ino))
109 # define MATCHING_INO(dp, ino) true
113 # define __getcwd getcwd
114 # define __lstat lstat
115 # define __closedir closedir
116 # define __opendir opendir
117 # define __readdir readdir
120 /* Get the name of the current working directory, and put it in SIZE
121 bytes of BUF. Returns NULL if the directory couldn't be determined or
122 SIZE was too small. If successful, returns BUF. In GNU, if BUF is
123 NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
124 unless SIZE == 0, in which case it is as big as necessary. */
127 __getcwd (char *buf, size_t size)
129 /* Lengths of big file name components and entire file names, and a
130 deep level of file name nesting. These numbers are not upper
131 bounds; they are merely large values suitable for initial
132 allocations, designed to be large enough for most real-world
136 BIG_FILE_NAME_COMPONENT_LENGTH = 255,
137 BIG_FILE_NAME_LENGTH = MIN (4095, PATH_MAX - 1),
143 bool fd_needs_closing = false;
145 char dots[DEEP_NESTING * sizeof ".." + BIG_FILE_NAME_COMPONENT_LENGTH + 1];
146 char *dotlist = dots;
147 size_t dotsize = sizeof dots;
150 DIR *dirstream = NULL;
151 dev_t rootdev, thisdev;
152 ino_t rootino, thisino;
156 size_t allocated = size;
159 #if HAVE_PARTLY_WORKING_GETCWD && !defined AT_FDCWD
160 /* The system getcwd works, except it sometimes fails when it
161 shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT. If
162 AT_FDCWD is not defined, the algorithm below is O(N**2) and this
163 is much slower than the system getcwd (at least on GNU/Linux).
164 So trust the system getcwd's results unless they look
167 dir = getcwd (buf, size);
168 if (dir || (errno != ERANGE && !is_ENAMETOOLONG (errno) && errno != ENOENT))
176 __set_errno (EINVAL);
180 allocated = BIG_FILE_NAME_LENGTH + 1;
185 dir = malloc (allocated);
192 dirp = dir + allocated;
195 if (__lstat (".", &st) < 0)
200 if (__lstat ("/", &st) < 0)
205 while (!(thisdev == rootdev && thisino == rootino))
215 /* Look at the parent directory. */
217 fd = openat (fd, "..", O_RDONLY);
220 fd_needs_closing = true;
221 parent_status = fstat (fd, &st);
223 dotlist[dotlen++] = '.';
224 dotlist[dotlen++] = '.';
225 dotlist[dotlen] = '\0';
226 parent_status = __lstat (dotlist, &st);
228 if (parent_status != 0)
231 if (dirstream && __closedir (dirstream) != 0)
237 /* Figure out if this directory is a mount point. */
240 mount_point = dotdev != thisdev;
242 /* Search for the last directory. */
244 dirstream = fdopendir (fd);
245 if (dirstream == NULL)
247 fd_needs_closing = false;
249 dirstream = __opendir (dotlist);
250 if (dirstream == NULL)
252 dotlist[dotlen++] = '/';
256 /* Clear errno to distinguish EOF from error if readdir returns
259 d = __readdir (dirstream);
263 /* EOF on dirstream, which means that the current directory
265 __set_errno (ENOENT);
268 if (d->d_name[0] == '.' &&
269 (d->d_name[1] == '\0' ||
270 (d->d_name[1] == '.' && d->d_name[2] == '\0')))
272 if (MATCHING_INO (d, thisino) || mount_point)
276 entry_status = fstatat (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW);
278 /* Compute size needed for this file name, or for the file
279 name ".." in the same directory, whichever is larger.
280 Room for ".." might be needed the next time through
282 size_t name_alloc = _D_ALLOC_NAMLEN (d);
283 size_t filesize = dotlen + MAX (sizeof "..", name_alloc);
285 if (filesize < dotlen)
286 goto memory_exhausted;
288 if (dotsize < filesize)
290 /* My, what a deep directory tree you have, Grandma. */
291 size_t newsize = MAX (filesize, dotsize * 2);
293 if (newsize < dotsize)
294 goto memory_exhausted;
297 dotlist = malloc (newsize);
312 strcpy (dotlist + dotlen, d->d_name);
313 entry_status = __lstat (dotlist, &st);
315 /* We don't fail here if we cannot stat() a directory entry.
316 This can happen when (network) file systems fail. If this
317 entry is in fact the one we are looking for we will find
318 out soon as we reach the end of the directory without
319 having found anything. */
320 if (entry_status == 0 && S_ISDIR (st.st_mode)
321 && st.st_dev == thisdev && st.st_ino == thisino)
326 dirroom = dirp - dir;
327 namlen = _D_EXACT_NAMLEN (d);
329 if (dirroom <= namlen)
333 __set_errno (ERANGE);
339 size_t oldsize = allocated;
341 allocated += MAX (allocated, namlen);
342 if (allocated < oldsize
343 || ! (tmp = realloc (dir, allocated)))
344 goto memory_exhausted;
346 /* Move current contents up to the end of the buffer.
347 This is guaranteed to be non-overlapping. */
348 dirp = memcpy (tmp + allocated - (oldsize - dirroom),
355 memcpy (dirp, d->d_name, namlen);
362 if (dirstream && __closedir (dirstream) != 0)
368 if (dirp == &dir[allocated - 1])
376 used = dir + allocated - dirp;
377 memmove (dir, dirp, used);
379 if (buf == NULL && size == 0)
380 /* Ensure that the buffer is only as large as necessary. */
381 buf = realloc (dir, used);
384 /* Either buf was NULL all along, or `realloc' failed but
385 we still have the original string. */
391 __set_errno (ENOMEM);
396 __closedir (dirstream);
398 if (fd_needs_closing)
412 weak_alias (__getcwd, getcwd)