1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2009 Free Software Foundation, Inc.
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 3 of the License, or
8 (at your option) any later version.
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
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC
31 #if HAVE_SYS_PARAM_H || defined _LIBC
32 # include <sys/param.h>
39 # include <shlib-compat.h>
41 # define SHLIB_COMPAT(lib, introduced, obsoleted) 0
42 # define versioned_symbol(lib, local, symbol, version)
43 # define compat_symbol(lib, local, symbol, version)
44 # define weak_alias(local, symbol)
45 # define __canonicalize_file_name canonicalize_file_name
46 # define __realpath realpath
51 /* We want the directory in Unix syntax, not in VMS syntax. */
52 # define __getcwd(buf, max) getcwd (buf, max, 0)
54 # define __getcwd getcwd
57 # define __getcwd(buf, max) getwd (buf)
59 # define __readlink readlink
60 # define __set_errno(e) errno = (e)
63 # define MAXSYMLINKS SYMLOOP_MAX
65 # define MAXSYMLINKS 20
70 #if !FUNC_REALPATH_WORKS || defined _LIBC
71 /* Return the canonical absolute name of file NAME. A canonical name
72 does not contain any `.', `..' components nor any repeated path
73 separators ('/') or symlinks. All path components must exist. If
74 RESOLVED is null, the result is malloc'd; otherwise, if the
75 canonical name is PATH_MAX chars or more, returns null with `errno'
76 set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
77 returns the name in RESOLVED. If the name cannot be resolved and
78 RESOLVED is non-NULL, it contains the path of the first component
79 that cannot be resolved. If the path can be resolved, RESOLVED
80 holds the same value as the value returned. */
83 __realpath (const char *name, char *resolved)
85 char *rpath, *dest, *extra_buf = NULL;
86 const char *start, *end, *rpath_limit;
92 /* As per Single Unix Specification V2 we must return an error if
93 either parameter is a null pointer. We extend this to allow
94 the RESOLVED parameter to be NULL in case the we are expected to
95 allocate the room for the return value. */
102 /* As per Single Unix Specification V2 we must return an error if
103 the name argument points to an empty string. */
104 __set_errno (ENOENT);
111 path_max = pathconf (name, _PC_PATH_MAX);
116 if (resolved == NULL)
118 rpath = malloc (path_max);
121 /* It's easier to set errno to ENOMEM than to rely on the
122 'malloc-posix' gnulib module. */
129 rpath_limit = rpath + path_max;
133 if (!__getcwd (rpath, path_max))
138 dest = strchr (rpath, '\0');
146 for (start = end = name; *start; start = end)
155 /* Skip sequence of multiple path-separators. */
156 while (*start == '/')
159 /* Find end of path component. */
160 for (end = start; *end && *end != '/'; ++end)
163 if (end - start == 0)
165 else if (end - start == 1 && start[0] == '.')
167 else if (end - start == 2 && start[0] == '.' && start[1] == '.')
169 /* Back up to previous component, ignore if at root already. */
170 if (dest > rpath + 1)
171 while ((--dest)[-1] != '/');
180 if (dest + (end - start) >= rpath_limit)
182 ptrdiff_t dest_offset = dest - rpath;
187 __set_errno (ENAMETOOLONG);
188 if (dest > rpath + 1)
193 new_size = rpath_limit - rpath;
194 if (end - start + 1 > path_max)
195 new_size += end - start + 1;
197 new_size += path_max;
198 new_rpath = (char *) realloc (rpath, new_size);
199 if (new_rpath == NULL)
201 /* It's easier to set errno to ENOMEM than to rely on the
202 'realloc-posix' gnulib module. */
207 rpath_limit = rpath + new_size;
209 dest = rpath + dest_offset;
213 dest = __mempcpy (dest, start, end - start);
215 memcpy (dest, start, end - start);
221 if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
223 if (lstat (rpath, &st) < 0)
227 if (S_ISLNK (st.st_mode))
232 if (++num_links > MAXSYMLINKS)
238 buf = malloca (path_max);
245 n = __readlink (rpath, buf, path_max - 1);
248 int saved_errno = errno;
257 extra_buf = malloca (path_max);
267 if ((long int) (n + len) >= path_max)
270 __set_errno (ENAMETOOLONG);
274 /* Careful here, end may be a pointer into extra_buf... */
275 memmove (&extra_buf[n], end, len + 1);
276 name = end = memcpy (extra_buf, buf, n);
279 dest = rpath + 1; /* It's an absolute symlink */
281 /* Back up to previous component, ignore if at root already: */
282 if (dest > rpath + 1)
283 while ((--dest)[-1] != '/');
285 else if (!S_ISDIR (st.st_mode) && *end != '\0')
287 __set_errno (ENOTDIR);
292 if (dest > rpath + 1 && dest[-1] == '/')
303 int saved_errno = errno;
306 if (resolved == NULL)
312 versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
313 #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */
316 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
318 attribute_compat_text_section
319 __old_realpath (const char *name, char *resolved)
321 if (resolved == NULL)
323 __set_errno (EINVAL);
327 return __realpath (name, resolved);
329 compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
334 __canonicalize_file_name (const char *name)
336 return __realpath (name, NULL);
338 weak_alias (__canonicalize_file_name, canonicalize_file_name)
342 /* This declaration is solely to ensure that after preprocessing
343 this file is never empty. */