1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2015 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/>. */
19 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
20 optimizes away the name == NULL test below. */
21 # define _GL_ARG_NONNULL(params)
23 # define _GL_USE_STDLIB_ALLOC 1
27 #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC
36 #if HAVE_SYS_PARAM_H || defined _LIBC
37 # include <sys/param.h>
44 # include <shlib-compat.h>
46 # define SHLIB_COMPAT(lib, introduced, obsoleted) 0
47 # define versioned_symbol(lib, local, symbol, version) extern int dummy
48 # define compat_symbol(lib, local, symbol, version)
49 # define weak_alias(local, symbol)
50 # define __canonicalize_file_name canonicalize_file_name
51 # define __realpath realpath
57 /* When building the relocatable program wrapper, use the system's getcwd
58 function, not the gnulib override, otherwise we would get a link error.
63 /* We want the directory in Unix syntax, not in VMS syntax. */
64 # define __getcwd(buf, max) getcwd (buf, max, 0)
66 # define __getcwd getcwd
69 # define __getcwd(buf, max) getwd (buf)
71 # define __readlink readlink
72 # define __set_errno(e) errno = (e)
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
;
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
;
148 /* This is always zero for Posix hosts, but can be 2 for MS-Windows
149 and MS-DOS X:/foo/bar file names. */
150 prefix_len
= FILE_SYSTEM_PREFIX_LEN (name
);
152 if (!IS_ABSOLUTE_FILE_NAME (name
))
154 if (!__getcwd (rpath
, path_max
))
159 dest
= strchr (rpath
, '\0');
161 prefix_len
= FILE_SYSTEM_PREFIX_LEN (rpath
);
168 memcpy (rpath
, name
, prefix_len
);
172 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
)
174 if (ISSLASH (name
[1]) && !ISSLASH (name
[2]) && !prefix_len
)
178 start
= name
+ prefix_len
;
181 for (end
= start
; *start
; start
= end
)
190 /* Skip sequence of multiple path-separators. */
191 while (ISSLASH (*start
))
194 /* Find end of path component. */
195 for (end
= start
; *end
&& !ISSLASH (*end
); ++end
)
198 if (end
- start
== 0)
200 else if (end
- start
== 1 && start
[0] == '.')
202 else if (end
- start
== 2 && start
[0] == '.' && start
[1] == '.')
204 /* Back up to previous component, ignore if at root already. */
205 if (dest
> rpath
+ prefix_len
+ 1)
206 for (--dest
; dest
> rpath
&& !ISSLASH (dest
[-1]); --dest
)
208 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
209 && dest
== rpath
+ 1 && !prefix_len
210 && ISSLASH (*dest
) && !ISSLASH (dest
[1]))
217 if (!ISSLASH (dest
[-1]))
220 if (dest
+ (end
- start
) >= rpath_limit
)
222 ptrdiff_t dest_offset
= dest
- rpath
;
227 __set_errno (ENAMETOOLONG
);
228 if (dest
> rpath
+ prefix_len
+ 1)
233 new_size
= rpath_limit
- rpath
;
234 if (end
- start
+ 1 > path_max
)
235 new_size
+= end
- start
+ 1;
237 new_size
+= path_max
;
238 new_rpath
= (char *) realloc (rpath
, new_size
);
239 if (new_rpath
== NULL
)
241 /* It's easier to set errno to ENOMEM than to rely on the
242 'realloc-posix' gnulib module. */
247 rpath_limit
= rpath
+ new_size
;
249 dest
= rpath
+ dest_offset
;
253 dest
= __mempcpy (dest
, start
, end
- start
);
255 memcpy (dest
, start
, end
- start
);
261 if (__lxstat64 (_STAT_VER
, rpath
, &st
) < 0)
263 if (lstat (rpath
, &st
) < 0)
267 if (S_ISLNK (st
.st_mode
))
272 if (++num_links
> MAXSYMLINKS
)
278 buf
= malloca (path_max
);
285 n
= __readlink (rpath
, buf
, path_max
- 1);
288 int saved_errno
= errno
;
297 extra_buf
= malloca (path_max
);
307 if ((long int) (n
+ len
) >= path_max
)
310 __set_errno (ENAMETOOLONG
);
314 /* Careful here, end may be a pointer into extra_buf... */
315 memmove (&extra_buf
[n
], end
, len
+ 1);
316 name
= end
= memcpy (extra_buf
, buf
, n
);
318 if (IS_ABSOLUTE_FILE_NAME (buf
))
320 size_t pfxlen
= FILE_SYSTEM_PREFIX_LEN (buf
);
323 memcpy (rpath
, buf
, pfxlen
);
324 dest
= rpath
+ pfxlen
;
325 *dest
++ = '/'; /* It's an absolute symlink */
326 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
)
328 if (ISSLASH (buf
[1]) && !ISSLASH (buf
[2]) && !pfxlen
)
332 /* Install the new prefix to be in effect hereafter. */
337 /* Back up to previous component, ignore if at root
339 if (dest
> rpath
+ prefix_len
+ 1)
340 for (--dest
; dest
> rpath
&& !ISSLASH (dest
[-1]); --dest
)
342 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
&& dest
== rpath
+ 1
343 && ISSLASH (*dest
) && !ISSLASH (dest
[1]) && !prefix_len
)
347 else if (!S_ISDIR (st
.st_mode
) && *end
!= '\0')
349 __set_errno (ENOTDIR
);
354 if (dest
> rpath
+ prefix_len
+ 1 && ISSLASH (dest
[-1]))
356 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
&& dest
== rpath
+ 1 && !prefix_len
357 && ISSLASH (*dest
) && !ISSLASH (dest
[1]))
368 int saved_errno
= errno
;
371 if (resolved
== NULL
)
377 versioned_symbol (libc
, __realpath
, realpath
, GLIBC_2_3
);
378 #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */
381 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
383 attribute_compat_text_section
384 __old_realpath (const char *name
, char *resolved
)
386 if (resolved
== NULL
)
388 __set_errno (EINVAL
);
392 return __realpath (name
, resolved
);
394 compat_symbol (libc
, __old_realpath
, realpath
, GLIBC_2_0
);
399 __canonicalize_file_name (const char *name
)
401 return __realpath (name
, NULL
);
403 weak_alias (__canonicalize_file_name
, canonicalize_file_name
)
407 /* This declaration is solely to ensure that after preprocessing
408 this file is never empty. */