1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2003, 2005-2008 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/>. */
20 /* Avoid a clash of our rpl_realpath() function with the prototype in
21 <stdlib.h> on Solaris 2.5.1. */
24 #if !HAVE_CANONICALIZE_FILE_NAME || defined _LIBC
29 #include "canonicalize.h"
35 #if HAVE_UNISTD_H || defined _LIBC
41 #if HAVE_SYS_PARAM_H || defined _LIBC
42 # include <sys/param.h>
45 # define MAXSYMLINKS 20
52 # define __set_errno(e) errno = (e)
54 # define ENAMETOOLONG EINVAL
59 # include <shlib-compat.h>
61 # define SHLIB_COMPAT(lib, introduced, obsoleted) 0
62 # define versioned_symbol(lib, local, symbol, version)
63 # define compat_symbol(lib, local, symbol, version)
64 # define weak_alias(local, symbol)
65 # define __canonicalize_file_name canonicalize_file_name
66 # define __realpath rpl_realpath
71 /* We want the directory in Unix syntax, not in VMS syntax. */
72 # define __getcwd(buf, max) getcwd (buf, max, 0)
74 # define __getcwd getcwd
77 # define __getcwd(buf, max) getwd (buf)
79 # define __readlink readlink
80 /* On systems without symbolic links, call stat() instead of lstat(). */
81 # if !defined S_ISLNK && !HAVE_READLINK
86 /* Return the canonical absolute name of file NAME. A canonical name
87 does not contain any `.', `..' components nor any repeated path
88 separators ('/') or symlinks. All path components must exist. If
89 RESOLVED is null, the result is malloc'd; otherwise, if the
90 canonical name is PATH_MAX chars or more, returns null with `errno'
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. */
98 __realpath (const char *name, char *resolved)
100 char *rpath, *dest, *extra_buf = NULL;
101 const char *start, *end, *rpath_limit;
109 /* As per Single Unix Specification V2 we must return an error if
110 either parameter is a null pointer. We extend this to allow
111 the RESOLVED parameter to be NULL in case the we are expected to
112 allocate the room for the return value. */
113 __set_errno (EINVAL);
119 /* As per Single Unix Specification V2 we must return an error if
120 the name argument points to an empty string. */
121 __set_errno (ENOENT);
128 path_max = pathconf (name, _PC_PATH_MAX);
133 if (resolved == NULL)
135 rpath = malloc (path_max);
138 /* It's easier to set errno to ENOMEM than to rely on the
139 'malloc-posix' gnulib module. */
146 rpath_limit = rpath + path_max;
150 if (!__getcwd (rpath, path_max))
155 dest = strchr (rpath, '\0');
163 for (start = end = name; *start; start = end)
171 /* Skip sequence of multiple path-separators. */
172 while (*start == '/')
175 /* Find end of path component. */
176 for (end = start; *end && *end != '/'; ++end)
179 if (end - start == 0)
181 else if (end - start == 1 && start[0] == '.')
183 else if (end - start == 2 && start[0] == '.' && start[1] == '.')
185 /* Back up to previous component, ignore if at root already. */
186 if (dest > rpath + 1)
187 while ((--dest)[-1] != '/');
196 if (dest + (end - start) >= rpath_limit)
198 ptrdiff_t dest_offset = dest - rpath;
203 __set_errno (ENAMETOOLONG);
204 if (dest > rpath + 1)
209 new_size = rpath_limit - rpath;
210 if (end - start + 1 > path_max)
211 new_size += end - start + 1;
213 new_size += path_max;
214 new_rpath = (char *) realloc (rpath, new_size);
215 if (new_rpath == NULL)
217 /* It's easier to set errno to ENOMEM than to rely on the
218 'realloc-posix' gnulib module. */
223 rpath_limit = rpath + new_size;
225 dest = rpath + dest_offset;
229 dest = __mempcpy (dest, start, end - start);
231 memcpy (dest, start, end - start);
237 if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
239 if (lstat (rpath, &st) < 0)
244 if (S_ISLNK (st.st_mode))
250 if (++num_links > MAXSYMLINKS)
256 buf = malloca (path_max);
263 n = __readlink (rpath, buf, path_max - 1);
266 int saved_errno = errno;
275 extra_buf = malloca (path_max);
285 if ((long int) (n + len) >= path_max)
288 __set_errno (ENAMETOOLONG);
292 /* Careful here, end may be a pointer into extra_buf... */
293 memmove (&extra_buf[n], end, len + 1);
294 name = end = memcpy (extra_buf, buf, n);
297 dest = rpath + 1; /* It's an absolute symlink */
299 /* Back up to previous component, ignore if at root already: */
300 if (dest > rpath + 1)
301 while ((--dest)[-1] != '/');
306 if (dest > rpath + 1 && dest[-1] == '/')
313 return resolved ? memcpy (resolved, rpath, dest - rpath + 1) : rpath;
317 int saved_errno = errno;
321 strcpy (resolved, rpath);
329 versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
333 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
335 __old_realpath (const char *name, char *resolved)
337 if (resolved == NULL)
339 __set_errno (EINVAL);
343 return __realpath (name, resolved);
345 compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
350 __canonicalize_file_name (const char *name)
352 return __realpath (name, NULL);
354 weak_alias (__canonicalize_file_name, canonicalize_file_name)
358 /* This declaration is solely to ensure that after preprocessing
359 this file is never empty. */