1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
28 #include <eloop-threshold.h>
29 #include <shlib-compat.h>
31 /* Return the canonical absolute name of file NAME. A canonical name
32 does not contain any `.', `..' components nor any repeated path
33 separators ('/') or symlinks. All path components must exist. If
34 RESOLVED is null, the result is malloc'd; otherwise, if the
35 canonical name is PATH_MAX chars or more, returns null with `errno'
36 set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
37 returns the name in RESOLVED. If the name cannot be resolved and
38 RESOLVED is non-NULL, it contains the path of the first component
39 that cannot be resolved. If the path can be resolved, RESOLVED
40 holds the same value as the value returned. */
43 __realpath (const char *name
, char *resolved
)
45 char *rpath
, *dest
, *extra_buf
= NULL
;
46 const char *start
, *end
, *rpath_limit
;
52 /* As per Single Unix Specification V2 we must return an error if
53 either parameter is a null pointer. We extend this to allow
54 the RESOLVED parameter to be NULL in case the we are expected to
55 allocate the room for the return value. */
62 /* As per Single Unix Specification V2 we must return an error if
63 the name argument points to an empty string. */
71 path_max
= pathconf (name
, _PC_PATH_MAX
);
78 rpath
= malloc (path_max
);
84 rpath_limit
= rpath
+ path_max
;
88 if (!__getcwd (rpath
, path_max
))
93 dest
= __rawmemchr (rpath
, '\0');
101 for (start
= end
= name
; *start
; start
= end
)
106 /* Skip sequence of multiple path-separators. */
107 while (*start
== '/')
110 /* Find end of path component. */
111 for (end
= start
; *end
&& *end
!= '/'; ++end
)
114 if (end
- start
== 0)
116 else if (end
- start
== 1 && start
[0] == '.')
118 else if (end
- start
== 2 && start
[0] == '.' && start
[1] == '.')
120 /* Back up to previous component, ignore if at root already. */
121 if (dest
> rpath
+ 1)
122 while ((--dest
)[-1] != '/');
131 if (dest
+ (end
- start
) >= rpath_limit
)
133 ptrdiff_t dest_offset
= dest
- rpath
;
138 __set_errno (ENAMETOOLONG
);
139 if (dest
> rpath
+ 1)
144 new_size
= rpath_limit
- rpath
;
145 if (end
- start
+ 1 > path_max
)
146 new_size
+= end
- start
+ 1;
148 new_size
+= path_max
;
149 new_rpath
= (char *) realloc (rpath
, new_size
);
150 if (new_rpath
== NULL
)
153 rpath_limit
= rpath
+ new_size
;
155 dest
= rpath
+ dest_offset
;
158 dest
= __mempcpy (dest
, start
, end
- start
);
161 if (__lxstat64 (_STAT_VER
, rpath
, &st
) < 0)
164 if (S_ISLNK (st
.st_mode
))
166 char *buf
= __alloca (path_max
);
169 if (++num_links
> __eloop_threshold ())
175 n
= __readlink (rpath
, buf
, path_max
- 1);
181 extra_buf
= __alloca (path_max
);
184 if ((long int) (n
+ len
) >= path_max
)
186 __set_errno (ENAMETOOLONG
);
190 /* Careful here, end may be a pointer into extra_buf... */
191 memmove (&extra_buf
[n
], end
, len
+ 1);
192 name
= end
= memcpy (extra_buf
, buf
, n
);
195 dest
= rpath
+ 1; /* It's an absolute symlink */
197 /* Back up to previous component, ignore if at root already: */
198 if (dest
> rpath
+ 1)
199 while ((--dest
)[-1] != '/');
201 else if (!S_ISDIR (st
.st_mode
) && *end
!= '\0')
203 __set_errno (ENOTDIR
);
208 if (dest
> rpath
+ 1 && dest
[-1] == '/')
212 assert (resolved
== NULL
|| resolved
== rpath
);
216 assert (resolved
== NULL
|| resolved
== rpath
);
217 if (resolved
== NULL
)
221 versioned_symbol (libc
, __realpath
, realpath
, GLIBC_2_3
);
224 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
226 attribute_compat_text_section
227 __old_realpath (const char *name
, char *resolved
)
229 if (resolved
== NULL
)
231 __set_errno (EINVAL
);
235 return __realpath (name
, resolved
);
237 compat_symbol (libc
, __old_realpath
, realpath
, GLIBC_2_0
);
242 __canonicalize_file_name (const char *name
)
244 return __realpath (name
, NULL
);
246 weak_alias (__canonicalize_file_name
, canonicalize_file_name
)