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424 lines
12 KiB
424 lines
12 KiB
/* Return the canonical absolute name of a given file. |
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Copyright (C) 1996-2017 Free Software Foundation, Inc. |
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This file is part of the GNU C Library. |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
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#ifndef _LIBC |
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/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc |
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optimizes away the name == NULL test below. */ |
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# define _GL_ARG_NONNULL(params) |
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# define _GL_USE_STDLIB_ALLOC 1 |
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# include <config.h> |
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#endif |
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#if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC |
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/* Specification. */ |
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#include <stdlib.h> |
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#include <alloca.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include <limits.h> |
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#if HAVE_SYS_PARAM_H || defined _LIBC |
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# include <sys/param.h> |
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#endif |
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#include <sys/stat.h> |
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#include <errno.h> |
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#include <stddef.h> |
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#ifdef _LIBC |
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# include <shlib-compat.h> |
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#else |
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# define SHLIB_COMPAT(lib, introduced, obsoleted) 0 |
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# define versioned_symbol(lib, local, symbol, version) extern int dummy |
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# define compat_symbol(lib, local, symbol, version) |
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# define weak_alias(local, symbol) |
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# define __canonicalize_file_name canonicalize_file_name |
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# define __realpath realpath |
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# include "pathmax.h" |
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# include "malloca.h" |
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# include "dosname.h" |
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# if HAVE_GETCWD |
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# if IN_RELOCWRAPPER |
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/* When building the relocatable program wrapper, use the system's getcwd |
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function, not the gnulib override, otherwise we would get a link error. |
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*/ |
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# undef getcwd |
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# endif |
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# ifdef VMS |
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/* We want the directory in Unix syntax, not in VMS syntax. */ |
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# define __getcwd(buf, max) getcwd (buf, max, 0) |
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# else |
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# define __getcwd getcwd |
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# endif |
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# else |
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# define __getcwd(buf, max) getwd (buf) |
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# endif |
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# define __readlink readlink |
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# define __set_errno(e) errno = (e) |
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# ifndef MAXSYMLINKS |
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# ifdef SYMLOOP_MAX |
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# define MAXSYMLINKS SYMLOOP_MAX |
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# else |
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# define MAXSYMLINKS 20 |
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# endif |
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# endif |
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#endif |
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#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT |
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# define DOUBLE_SLASH_IS_DISTINCT_ROOT 0 |
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#endif |
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/* Define this independently so that stdint.h is not a prerequisite. */ |
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#ifndef SIZE_MAX |
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# define SIZE_MAX ((size_t) -1) |
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#endif |
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#if !FUNC_REALPATH_WORKS || defined _LIBC |
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static void |
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alloc_failed (void) |
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{ |
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#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ |
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/* Avoid errno problem without using the malloc or realloc modules; see: |
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http://lists.gnu.org/archive/html/bug-gnulib/2016-08/msg00025.html */ |
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errno = ENOMEM; |
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#endif |
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} |
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/* Return the canonical absolute name of file NAME. A canonical name |
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does not contain any ".", ".." components nor any repeated path |
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separators ('/') or symlinks. All path components must exist. If |
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RESOLVED is null, the result is malloc'd; otherwise, if the |
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canonical name is PATH_MAX chars or more, returns null with 'errno' |
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set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, |
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returns the name in RESOLVED. If the name cannot be resolved and |
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RESOLVED is non-NULL, it contains the path of the first component |
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that cannot be resolved. If the path can be resolved, RESOLVED |
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holds the same value as the value returned. */ |
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char * |
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__realpath (const char *name, char *resolved) |
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{ |
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char *rpath, *dest, *extra_buf = NULL; |
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const char *start, *end, *rpath_limit; |
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long int path_max; |
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int num_links = 0; |
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size_t prefix_len; |
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if (name == NULL) |
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{ |
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/* As per Single Unix Specification V2 we must return an error if |
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either parameter is a null pointer. We extend this to allow |
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the RESOLVED parameter to be NULL in case the we are expected to |
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allocate the room for the return value. */ |
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__set_errno (EINVAL); |
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return NULL; |
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} |
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if (name[0] == '\0') |
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{ |
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/* As per Single Unix Specification V2 we must return an error if |
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the name argument points to an empty string. */ |
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__set_errno (ENOENT); |
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return NULL; |
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} |
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#ifdef PATH_MAX |
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path_max = PATH_MAX; |
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#else |
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path_max = pathconf (name, _PC_PATH_MAX); |
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if (path_max <= 0) |
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path_max = 8192; |
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#endif |
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if (resolved == NULL) |
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{ |
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rpath = malloc (path_max); |
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if (rpath == NULL) |
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{ |
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alloc_failed (); |
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return NULL; |
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} |
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} |
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else |
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rpath = resolved; |
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rpath_limit = rpath + path_max; |
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/* This is always zero for Posix hosts, but can be 2 for MS-Windows |
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and MS-DOS X:/foo/bar file names. */ |
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prefix_len = FILE_SYSTEM_PREFIX_LEN (name); |
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if (!IS_ABSOLUTE_FILE_NAME (name)) |
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{ |
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if (!__getcwd (rpath, path_max)) |
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{ |
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rpath[0] = '\0'; |
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goto error; |
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} |
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dest = strchr (rpath, '\0'); |
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start = name; |
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prefix_len = FILE_SYSTEM_PREFIX_LEN (rpath); |
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} |
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else |
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{ |
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dest = rpath; |
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if (prefix_len) |
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{ |
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memcpy (rpath, name, prefix_len); |
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dest += prefix_len; |
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} |
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*dest++ = '/'; |
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
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{ |
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if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len) |
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*dest++ = '/'; |
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*dest = '\0'; |
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} |
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start = name + prefix_len; |
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} |
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for (end = start; *start; start = end) |
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{ |
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#ifdef _LIBC |
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struct stat64 st; |
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#else |
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struct stat st; |
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#endif |
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/* Skip sequence of multiple path-separators. */ |
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while (ISSLASH (*start)) |
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++start; |
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/* Find end of path component. */ |
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for (end = start; *end && !ISSLASH (*end); ++end) |
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/* Nothing. */; |
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if (end - start == 0) |
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break; |
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else if (end - start == 1 && start[0] == '.') |
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/* nothing */; |
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else if (end - start == 2 && start[0] == '.' && start[1] == '.') |
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{ |
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/* Back up to previous component, ignore if at root already. */ |
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if (dest > rpath + prefix_len + 1) |
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for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) |
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continue; |
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT |
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&& dest == rpath + 1 && !prefix_len |
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&& ISSLASH (*dest) && !ISSLASH (dest[1])) |
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dest++; |
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} |
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else |
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{ |
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size_t new_size; |
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if (!ISSLASH (dest[-1])) |
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*dest++ = '/'; |
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if (dest + (end - start) >= rpath_limit) |
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{ |
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ptrdiff_t dest_offset = dest - rpath; |
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char *new_rpath; |
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if (resolved) |
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{ |
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__set_errno (ENAMETOOLONG); |
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if (dest > rpath + prefix_len + 1) |
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dest--; |
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*dest = '\0'; |
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goto error; |
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} |
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new_size = rpath_limit - rpath; |
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if (end - start + 1 > path_max) |
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new_size += end - start + 1; |
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else |
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new_size += path_max; |
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new_rpath = (char *) realloc (rpath, new_size); |
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if (new_rpath == NULL) |
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{ |
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alloc_failed (); |
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goto error; |
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} |
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rpath = new_rpath; |
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rpath_limit = rpath + new_size; |
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dest = rpath + dest_offset; |
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} |
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#ifdef _LIBC |
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dest = __mempcpy (dest, start, end - start); |
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#else |
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memcpy (dest, start, end - start); |
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dest += end - start; |
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#endif |
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*dest = '\0'; |
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#ifdef _LIBC |
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if (__lxstat64 (_STAT_VER, rpath, &st) < 0) |
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#else |
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if (lstat (rpath, &st) < 0) |
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#endif |
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goto error; |
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if (S_ISLNK (st.st_mode)) |
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{ |
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char *buf; |
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size_t len; |
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ssize_t n; |
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if (++num_links > MAXSYMLINKS) |
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{ |
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__set_errno (ELOOP); |
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goto error; |
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} |
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buf = malloca (path_max); |
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if (!buf) |
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{ |
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__set_errno (ENOMEM); |
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goto error; |
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} |
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n = __readlink (rpath, buf, path_max - 1); |
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if (n < 0) |
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{ |
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int saved_errno = errno; |
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freea (buf); |
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__set_errno (saved_errno); |
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goto error; |
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} |
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buf[n] = '\0'; |
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if (!extra_buf) |
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{ |
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extra_buf = malloca (path_max); |
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if (!extra_buf) |
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{ |
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freea (buf); |
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__set_errno (ENOMEM); |
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goto error; |
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} |
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} |
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len = strlen (end); |
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/* Check that n + len + 1 doesn't overflow and is <= path_max. */ |
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if (n >= SIZE_MAX - len || n + len >= path_max) |
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{ |
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freea (buf); |
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__set_errno (ENAMETOOLONG); |
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goto error; |
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} |
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/* Careful here, end may be a pointer into extra_buf... */ |
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memmove (&extra_buf[n], end, len + 1); |
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name = end = memcpy (extra_buf, buf, n); |
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if (IS_ABSOLUTE_FILE_NAME (buf)) |
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{ |
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size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); |
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if (pfxlen) |
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memcpy (rpath, buf, pfxlen); |
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dest = rpath + pfxlen; |
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*dest++ = '/'; /* It's an absolute symlink */ |
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
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{ |
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if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen) |
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*dest++ = '/'; |
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*dest = '\0'; |
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} |
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/* Install the new prefix to be in effect hereafter. */ |
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prefix_len = pfxlen; |
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} |
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else |
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{ |
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/* Back up to previous component, ignore if at root |
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already: */ |
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if (dest > rpath + prefix_len + 1) |
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for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) |
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continue; |
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 |
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&& ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len) |
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dest++; |
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} |
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} |
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else if (!S_ISDIR (st.st_mode) && *end != '\0') |
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{ |
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__set_errno (ENOTDIR); |
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goto error; |
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} |
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} |
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} |
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if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1])) |
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--dest; |
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len |
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&& ISSLASH (*dest) && !ISSLASH (dest[1])) |
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dest++; |
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*dest = '\0'; |
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if (extra_buf) |
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freea (extra_buf); |
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return rpath; |
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error: |
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{ |
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int saved_errno = errno; |
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if (extra_buf) |
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freea (extra_buf); |
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if (resolved == NULL) |
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free (rpath); |
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__set_errno (saved_errno); |
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} |
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return NULL; |
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} |
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versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); |
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#endif /* !FUNC_REALPATH_WORKS || defined _LIBC */ |
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#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) |
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char * |
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attribute_compat_text_section |
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__old_realpath (const char *name, char *resolved) |
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{ |
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if (resolved == NULL) |
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{ |
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__set_errno (EINVAL); |
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return NULL; |
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} |
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return __realpath (name, resolved); |
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} |
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compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); |
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#endif |
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char * |
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__canonicalize_file_name (const char *name) |
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{ |
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return __realpath (name, NULL); |
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} |
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weak_alias (__canonicalize_file_name, canonicalize_file_name) |
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#else |
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/* This declaration is solely to ensure that after preprocessing |
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this file is never empty. */ |
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typedef int dummy; |
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#endif
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