1 /* Return the canonical absolute name of a given file.
2 Copyright (C) 1996-2012 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 # define _GL_USE_STDLIB_ALLOC 1
23 #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC
25 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
26 optimizes away the name == NULL test below. */
27 #define _GL_ARG_NONNULL(params)
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');
166 memcpy (rpath, name, prefix_len);
170 if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
172 if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len)
178 for (start = end = name + prefix_len; *start; start = end)
187 /* Skip sequence of multiple path-separators. */
188 while (ISSLASH (*start))
191 /* Find end of path component. */
192 for (end = start; *end && !ISSLASH (*end); ++end)
195 if (end - start == 0)
197 else if (end - start == 1 && start[0] == '.')
199 else if (end - start == 2 && start[0] == '.' && start[1] == '.')
201 /* Back up to previous component, ignore if at root already. */
202 if (dest > rpath + prefix_len + 1)
203 for (--dest; !ISSLASH (dest[-1]); --dest)
205 if (DOUBLE_SLASH_IS_DISTINCT_ROOT
206 && dest == rpath + 1 && !prefix_len
207 && ISSLASH (*dest) && !ISSLASH (dest[1]))
214 if (!ISSLASH (dest[-1]))
217 if (dest + (end - start) >= rpath_limit)
219 ptrdiff_t dest_offset = dest - rpath;
224 __set_errno (ENAMETOOLONG);
225 if (dest > rpath + prefix_len + 1)
230 new_size = rpath_limit - rpath;
231 if (end - start + 1 > path_max)
232 new_size += end - start + 1;
234 new_size += path_max;
235 new_rpath = (char *) realloc (rpath, new_size);
236 if (new_rpath == NULL)
238 /* It's easier to set errno to ENOMEM than to rely on the
239 'realloc-posix' gnulib module. */
244 rpath_limit = rpath + new_size;
246 dest = rpath + dest_offset;
250 dest = __mempcpy (dest, start, end - start);
252 memcpy (dest, start, end - start);
258 if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
260 if (lstat (rpath, &st) < 0)
264 if (S_ISLNK (st.st_mode))
269 if (++num_links > MAXSYMLINKS)
275 buf = malloca (path_max);
282 n = __readlink (rpath, buf, path_max - 1);
285 int saved_errno = errno;
294 extra_buf = malloca (path_max);
304 if ((long int) (n + len) >= path_max)
307 __set_errno (ENAMETOOLONG);
311 /* Careful here, end may be a pointer into extra_buf... */
312 memmove (&extra_buf[n], end, len + 1);
313 name = end = memcpy (extra_buf, buf, n);
315 if (IS_ABSOLUTE_FILE_NAME (buf))
317 size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf);
320 memcpy (rpath, buf, pfxlen);
321 dest = rpath + pfxlen;
322 *dest++ = '/'; /* It's an absolute symlink */
323 if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
325 if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen)
329 /* Install the new prefix to be in effect hereafter. */
334 /* Back up to previous component, ignore if at root
336 if (dest > rpath + prefix_len + 1)
337 for (--dest; !ISSLASH (dest[-1]); --dest)
339 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1
340 && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len)
344 else if (!S_ISDIR (st.st_mode) && *end != '\0')
346 __set_errno (ENOTDIR);
351 if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1]))
353 if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len
354 && ISSLASH (*dest) && !ISSLASH (dest[1]))
365 int saved_errno = errno;
368 if (resolved == NULL)
374 versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
375 #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */
378 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
380 attribute_compat_text_section
381 __old_realpath (const char *name, char *resolved)
383 if (resolved == NULL)
385 __set_errno (EINVAL);
389 return __realpath (name, resolved);
391 compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
396 __canonicalize_file_name (const char *name)
398 return __realpath (name, NULL);
400 weak_alias (__canonicalize_file_name, canonicalize_file_name)
404 /* This declaration is solely to ensure that after preprocessing
405 this file is never empty. */