1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2010 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
24 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
25 optimizes away the name == NULL test below. */
26 #define _GL_ARG_NONNULL(params)
35 #if HAVE_SYS_PARAM_H || defined _LIBC
36 # include <sys/param.h>
43 # include <shlib-compat.h>
45 # define SHLIB_COMPAT(lib, introduced, obsoleted) 0
46 # define versioned_symbol(lib, local, symbol, version) extern int dummy
47 # define compat_symbol(lib, local, symbol, version)
48 # define weak_alias(local, symbol)
49 # define __canonicalize_file_name canonicalize_file_name
50 # define __realpath realpath
55 /* When building the relocatable program wrapper, use the system's getcwd
56 function, not the gnulib override, otherwise we would get a link error.
61 /* We want the directory in Unix syntax, not in VMS syntax. */
62 # define __getcwd(buf, max) getcwd (buf, max, 0)
64 # define __getcwd getcwd
67 # define __getcwd(buf, max) getwd (buf)
69 # define __readlink readlink
70 # define __set_errno(e) errno = (e)
71 /* Use the system functions, not the gnulib overrides in this file. */
75 # define MAXSYMLINKS SYMLOOP_MAX
77 # define MAXSYMLINKS 20
82 #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
83 # define DOUBLE_SLASH_IS_DISTINCT_ROOT 0
86 #if !FUNC_REALPATH_WORKS || defined _LIBC
87 /* Return the canonical absolute name of file NAME. A canonical name
88 does not contain any `.', `..' components nor any repeated path
89 separators ('/') or symlinks. All path components must exist. If
90 RESOLVED is null, the result is malloc'd; otherwise, if the
91 canonical name is PATH_MAX chars or more, returns null with `errno'
92 set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
93 returns the name in RESOLVED. If the name cannot be resolved and
94 RESOLVED is non-NULL, it contains the path of the first component
95 that cannot be resolved. If the path can be resolved, RESOLVED
96 holds the same value as the value returned. */
99 __realpath (const char *name, char *resolved)
101 char *rpath, *dest, *extra_buf = NULL;
102 const char *start, *end, *rpath_limit;
108 /* As per Single Unix Specification V2 we must return an error if
109 either parameter is a null pointer. We extend this to allow
110 the RESOLVED parameter to be NULL in case the we are expected to
111 allocate the room for the return value. */
112 __set_errno (EINVAL);
118 /* As per Single Unix Specification V2 we must return an error if
119 the name argument points to an empty string. */
120 __set_errno (ENOENT);
127 path_max = pathconf (name, _PC_PATH_MAX);
132 if (resolved == NULL)
134 rpath = malloc (path_max);
137 /* It's easier to set errno to ENOMEM than to rely on the
138 'malloc-posix' gnulib module. */
145 rpath_limit = rpath + path_max;
149 if (!__getcwd (rpath, path_max))
154 dest = strchr (rpath, '\0');
160 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/')
164 for (start = end = name; *start; start = end)
173 /* Skip sequence of multiple path-separators. */
174 while (*start == '/')
177 /* Find end of path component. */
178 for (end = start; *end && *end != '/'; ++end)
181 if (end - start == 0)
183 else if (end - start == 1 && start[0] == '.')
185 else if (end - start == 2 && start[0] == '.' && start[1] == '.')
187 /* Back up to previous component, ignore if at root already. */
188 if (dest > rpath + 1)
189 while ((--dest)[-1] != '/');
190 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1
201 if (dest + (end - start) >= rpath_limit)
203 ptrdiff_t dest_offset = dest - rpath;
208 __set_errno (ENAMETOOLONG);
209 if (dest > rpath + 1)
214 new_size = rpath_limit - rpath;
215 if (end - start + 1 > path_max)
216 new_size += end - start + 1;
218 new_size += path_max;
219 new_rpath = (char *) realloc (rpath, new_size);
220 if (new_rpath == NULL)
222 /* It's easier to set errno to ENOMEM than to rely on the
223 'realloc-posix' gnulib module. */
228 rpath_limit = rpath + new_size;
230 dest = rpath + dest_offset;
234 dest = __mempcpy (dest, start, end - start);
236 memcpy (dest, start, end - start);
242 if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
244 if (lstat (rpath, &st) < 0)
248 if (S_ISLNK (st.st_mode))
253 if (++num_links > MAXSYMLINKS)
259 buf = malloca (path_max);
266 n = __readlink (rpath, buf, path_max - 1);
269 int saved_errno = errno;
278 extra_buf = malloca (path_max);
288 if ((long int) (n + len) >= path_max)
291 __set_errno (ENAMETOOLONG);
295 /* Careful here, end may be a pointer into extra_buf... */
296 memmove (&extra_buf[n], end, len + 1);
297 name = end = memcpy (extra_buf, buf, n);
301 dest = rpath + 1; /* It's an absolute symlink */
302 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && buf[1] == '/')
307 /* Back up to previous component, ignore if at root
309 if (dest > rpath + 1)
310 while ((--dest)[-1] != '/');
311 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1
316 else if (!S_ISDIR (st.st_mode) && *end != '\0')
318 __set_errno (ENOTDIR);
323 if (dest > rpath + 1 && dest[-1] == '/')
325 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && *dest == '/')
336 int saved_errno = errno;
339 if (resolved == NULL)
345 versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
346 #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */
349 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
351 attribute_compat_text_section
352 __old_realpath (const char *name, char *resolved)
354 if (resolved == NULL)
356 __set_errno (EINVAL);
360 return __realpath (name, resolved);
362 compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
367 __canonicalize_file_name (const char *name)
369 return __realpath (name, NULL);
371 weak_alias (__canonicalize_file_name, canonicalize_file_name)
375 /* This declaration is solely to ensure that after preprocessing
376 this file is never empty. */