1 /* Copyright (C) 1991,92,93,94,95,96,97,98,99,2004,2005 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
78 # define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
80 # define is_ENAMETOOLONG(x) 0
84 # define MAX(a, b) ((a) < (b) ? (b) : (a))
87 # define MIN(a, b) ((a) < (b) ? (a) : (b))
92 # define PATH_MAX MAXPATHLEN
94 # define PATH_MAX 1024
99 # define MATCHING_INO(dp, ino) ((dp)->d_ino == (ino))
101 # define MATCHING_INO(dp, ino) true
105 # define __getcwd getcwd
106 # define __lstat lstat
107 # define __closedir closedir
108 # define __opendir opendir
109 # define __readdir readdir
112 /* Get the name of the current working directory, and put it in SIZE
113 bytes of BUF. Returns NULL if the directory couldn't be determined or
114 SIZE was too small. If successful, returns BUF. In GNU, if BUF is
115 NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
116 unless SIZE == 0, in which case it is as big as necessary. */
119 __getcwd (char *buf, size_t size)
121 /* Lengths of big file name components and entire file names, and a
122 deep level of file name nesting. These numbers are not upper
123 bounds; they are merely large values suitable for initial
124 allocations, designed to be large enough for most real-world
128 BIG_FILE_NAME_COMPONENT_LENGTH = 255,
129 BIG_FILE_NAME_LENGTH = MIN (4095, PATH_MAX - 1),
135 bool fd_needs_closing = false;
137 char dots[DEEP_NESTING * sizeof ".." + BIG_FILE_NAME_COMPONENT_LENGTH + 1];
138 char *dotlist = dots;
139 size_t dotsize = sizeof dots;
142 DIR *dirstream = NULL;
143 dev_t rootdev, thisdev;
144 ino_t rootino, thisino;
148 size_t allocated = size;
151 #if HAVE_PARTLY_WORKING_GETCWD && !defined AT_FDCWD
152 /* The system getcwd works, except it sometimes fails when it
153 shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT. If
154 AT_FDCWD is not defined, the algorithm below is O(N**2) and this
155 is much slower than the system getcwd (at least on GNU/Linux).
156 So trust the system getcwd's results unless they look
159 dir = getcwd (buf, size);
160 if (dir || (errno != ERANGE && !is_ENAMETOOLONG (errno) && errno != ENOENT))
168 __set_errno (EINVAL);
172 allocated = BIG_FILE_NAME_LENGTH + 1;
177 dir = malloc (allocated);
184 dirp = dir + allocated;
187 if (__lstat (".", &st) < 0)
192 if (__lstat ("/", &st) < 0)
197 while (!(thisdev == rootdev && thisino == rootino))
205 /* Look at the parent directory. */
207 fd = openat (fd, "..", O_RDONLY);
210 fd_needs_closing = true;
211 parent_status = fstat (fd, &st);
213 dotlist[dotlen++] = '.';
214 dotlist[dotlen++] = '.';
215 dotlist[dotlen] = '\0';
216 parent_status = __lstat (dotlist, &st);
218 if (parent_status != 0)
221 if (dirstream && __closedir (dirstream) != 0)
227 /* Figure out if this directory is a mount point. */
230 mount_point = dotdev != thisdev;
232 /* Search for the last directory. */
234 dirstream = fdopendir (fd);
235 if (dirstream == NULL)
237 fd_needs_closing = false;
239 dirstream = __opendir (dotlist);
240 if (dirstream == NULL)
242 dotlist[dotlen++] = '/';
244 /* Clear errno to distinguish EOF from error if readdir returns
247 while ((d = __readdir (dirstream)) != NULL)
249 if (d->d_name[0] == '.' &&
250 (d->d_name[1] == '\0' ||
251 (d->d_name[1] == '.' && d->d_name[2] == '\0')))
253 if (MATCHING_INO (d, thisino) || mount_point)
257 entry_status = fstatat (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW);
259 /* Compute size needed for this file name, or for the file
260 name ".." in the same directory, whichever is larger.
261 Room for ".." might be needed the next time through
263 size_t name_alloc = _D_ALLOC_NAMLEN (d);
264 size_t filesize = dotlen + MAX (sizeof "..", name_alloc);
266 if (filesize < dotlen)
267 goto memory_exhausted;
269 if (dotsize < filesize)
271 /* My, what a deep directory tree you have, Grandma. */
272 size_t newsize = MAX (filesize, dotsize * 2);
274 if (newsize < dotsize)
275 goto memory_exhausted;
278 dotlist = malloc (newsize);
293 strcpy (dotlist + dotlen, d->d_name);
294 entry_status = __lstat (dotlist, &st);
296 /* We don't fail here if we cannot stat() a directory entry.
297 This can happen when (network) file systems fail. If this
298 entry is in fact the one we are looking for we will find
299 out soon as we reach the end of the directory without
300 having found anything. */
301 if (entry_status == 0 && S_ISDIR (st.st_mode)
302 && st.st_dev == thisdev && st.st_ino == thisino)
309 /* EOF on dirstream, which means that the current directory
311 __set_errno (ENOENT);
316 size_t dirroom = dirp - dir;
317 size_t namlen = _D_EXACT_NAMLEN (d);
319 if (dirroom <= namlen)
323 __set_errno (ERANGE);
329 size_t oldsize = allocated;
331 allocated += MAX (allocated, namlen);
332 if (allocated < oldsize
333 || ! (tmp = realloc (dir, allocated)))
334 goto memory_exhausted;
336 /* Move current contents up to the end of the buffer.
337 This is guaranteed to be non-overlapping. */
338 dirp = memcpy (tmp + allocated - (oldsize - dirroom),
345 memcpy (dirp, d->d_name, namlen);
353 if (dirstream && __closedir (dirstream) != 0)
359 if (dirp == &dir[allocated - 1])
367 used = dir + allocated - dirp;
368 memmove (dir, dirp, used);
370 if (buf == NULL && size == 0)
371 /* Ensure that the buffer is only as large as necessary. */
372 buf = realloc (dir, used);
375 /* Either buf was NULL all along, or `realloc' failed but
376 we still have the original string. */
382 __set_errno (ENOMEM);
387 __closedir (dirstream);
389 if (fd_needs_closing)
403 weak_alias (__getcwd, getcwd)