Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/stdlib/canonicalize.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
246 lines (210 sloc)
6.04 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Return the canonical absolute name of a given file. | |
Copyright (C) 1996-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <assert.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include <unistd.h> | |
#include <limits.h> | |
#include <sys/stat.h> | |
#include <errno.h> | |
#include <stddef.h> | |
#include <eloop-threshold.h> | |
#include <shlib-compat.h> | |
/* Return the canonical absolute name of file NAME. A canonical name | |
does not contain any `.', `..' components nor any repeated path | |
separators ('/') or symlinks. All path components must exist. If | |
RESOLVED is null, the result is malloc'd; otherwise, if the | |
canonical name is PATH_MAX chars or more, returns null with `errno' | |
set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, | |
returns the name in RESOLVED. If the name cannot be resolved and | |
RESOLVED is non-NULL, it contains the path of the first component | |
that cannot be resolved. If the path can be resolved, RESOLVED | |
holds the same value as the value returned. */ | |
char * | |
__realpath (const char *name, char *resolved) | |
{ | |
char *rpath, *dest, *extra_buf = NULL; | |
const char *start, *end, *rpath_limit; | |
long int path_max; | |
int num_links = 0; | |
if (name == NULL) | |
{ | |
/* As per Single Unix Specification V2 we must return an error if | |
either parameter is a null pointer. We extend this to allow | |
the RESOLVED parameter to be NULL in case the we are expected to | |
allocate the room for the return value. */ | |
__set_errno (EINVAL); | |
return NULL; | |
} | |
if (name[0] == '\0') | |
{ | |
/* As per Single Unix Specification V2 we must return an error if | |
the name argument points to an empty string. */ | |
__set_errno (ENOENT); | |
return NULL; | |
} | |
#ifdef PATH_MAX | |
path_max = PATH_MAX; | |
#else | |
path_max = pathconf (name, _PC_PATH_MAX); | |
if (path_max <= 0) | |
path_max = 1024; | |
#endif | |
if (resolved == NULL) | |
{ | |
rpath = malloc (path_max); | |
if (rpath == NULL) | |
return NULL; | |
} | |
else | |
rpath = resolved; | |
rpath_limit = rpath + path_max; | |
if (name[0] != '/') | |
{ | |
if (!__getcwd (rpath, path_max)) | |
{ | |
rpath[0] = '\0'; | |
goto error; | |
} | |
dest = __rawmemchr (rpath, '\0'); | |
} | |
else | |
{ | |
rpath[0] = '/'; | |
dest = rpath + 1; | |
} | |
for (start = end = name; *start; start = end) | |
{ | |
struct stat64 st; | |
int n; | |
/* Skip sequence of multiple path-separators. */ | |
while (*start == '/') | |
++start; | |
/* Find end of path component. */ | |
for (end = start; *end && *end != '/'; ++end) | |
/* Nothing. */; | |
if (end - start == 0) | |
break; | |
else if (end - start == 1 && start[0] == '.') | |
/* nothing */; | |
else if (end - start == 2 && start[0] == '.' && start[1] == '.') | |
{ | |
/* Back up to previous component, ignore if at root already. */ | |
if (dest > rpath + 1) | |
while ((--dest)[-1] != '/'); | |
} | |
else | |
{ | |
size_t new_size; | |
if (dest[-1] != '/') | |
*dest++ = '/'; | |
if (dest + (end - start) >= rpath_limit) | |
{ | |
ptrdiff_t dest_offset = dest - rpath; | |
char *new_rpath; | |
if (resolved) | |
{ | |
__set_errno (ENAMETOOLONG); | |
if (dest > rpath + 1) | |
dest--; | |
*dest = '\0'; | |
goto error; | |
} | |
new_size = rpath_limit - rpath; | |
if (end - start + 1 > path_max) | |
new_size += end - start + 1; | |
else | |
new_size += path_max; | |
new_rpath = (char *) realloc (rpath, new_size); | |
if (new_rpath == NULL) | |
goto error; | |
rpath = new_rpath; | |
rpath_limit = rpath + new_size; | |
dest = rpath + dest_offset; | |
} | |
dest = __mempcpy (dest, start, end - start); | |
*dest = '\0'; | |
if (__lxstat64 (_STAT_VER, rpath, &st) < 0) | |
goto error; | |
if (S_ISLNK (st.st_mode)) | |
{ | |
char *buf = __alloca (path_max); | |
size_t len; | |
if (++num_links > __eloop_threshold ()) | |
{ | |
__set_errno (ELOOP); | |
goto error; | |
} | |
n = __readlink (rpath, buf, path_max - 1); | |
if (n < 0) | |
goto error; | |
buf[n] = '\0'; | |
if (!extra_buf) | |
extra_buf = __alloca (path_max); | |
len = strlen (end); | |
if ((long int) (n + len) >= path_max) | |
{ | |
__set_errno (ENAMETOOLONG); | |
goto error; | |
} | |
/* Careful here, end may be a pointer into extra_buf... */ | |
memmove (&extra_buf[n], end, len + 1); | |
name = end = memcpy (extra_buf, buf, n); | |
if (buf[0] == '/') | |
dest = rpath + 1; /* It's an absolute symlink */ | |
else | |
/* Back up to previous component, ignore if at root already: */ | |
if (dest > rpath + 1) | |
while ((--dest)[-1] != '/'); | |
} | |
else if (!S_ISDIR (st.st_mode) && *end != '\0') | |
{ | |
__set_errno (ENOTDIR); | |
goto error; | |
} | |
} | |
} | |
if (dest > rpath + 1 && dest[-1] == '/') | |
--dest; | |
*dest = '\0'; | |
assert (resolved == NULL || resolved == rpath); | |
return rpath; | |
error: | |
assert (resolved == NULL || resolved == rpath); | |
if (resolved == NULL) | |
free (rpath); | |
return NULL; | |
} | |
versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); | |
#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) | |
char * | |
attribute_compat_text_section | |
__old_realpath (const char *name, char *resolved) | |
{ | |
if (resolved == NULL) | |
{ | |
__set_errno (EINVAL); | |
return NULL; | |
} | |
return __realpath (name, resolved); | |
} | |
compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); | |
#endif | |
char * | |
__canonicalize_file_name (const char *name) | |
{ | |
return __realpath (name, NULL); | |
} | |
weak_alias (__canonicalize_file_name, canonicalize_file_name) |