| /* Return the canonical absolute name of a given file. |
| Copyright (C) 1996-2019 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program 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 General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| #ifndef _LIBC |
| /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc |
| optimizes away the name == NULL test below. */ |
| # define _GL_ARG_NONNULL(params) |
| |
| # define _GL_USE_STDLIB_ALLOC 1 |
| # include <config.h> |
| #endif |
| |
| #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC |
| |
| /* Specification. */ |
| #include <stdlib.h> |
| |
| #include <alloca.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <limits.h> |
| #if HAVE_SYS_PARAM_H || defined _LIBC |
| # include <sys/param.h> |
| #endif |
| #include <sys/stat.h> |
| #include <errno.h> |
| #include <stddef.h> |
| |
| #ifdef _LIBC |
| # include <shlib-compat.h> |
| #else |
| # define SHLIB_COMPAT(lib, introduced, obsoleted) 0 |
| # define versioned_symbol(lib, local, symbol, version) extern int dummy |
| # define compat_symbol(lib, local, symbol, version) |
| # define weak_alias(local, symbol) |
| # define __canonicalize_file_name canonicalize_file_name |
| # define __realpath realpath |
| # include "pathmax.h" |
| # include "malloca.h" |
| # include "dosname.h" |
| # if HAVE_GETCWD |
| # if IN_RELOCWRAPPER |
| /* When building the relocatable program wrapper, use the system's getcwd |
| function, not the gnulib override, otherwise we would get a link error. |
| */ |
| # undef getcwd |
| # endif |
| # if defined VMS && !defined getcwd |
| /* We want the directory in Unix syntax, not in VMS syntax. |
| The gnulib override of 'getcwd' takes 2 arguments; the original VMS |
| 'getcwd' takes 3 arguments. */ |
| # define __getcwd(buf, max) getcwd (buf, max, 0) |
| # else |
| # define __getcwd getcwd |
| # endif |
| # else |
| # define __getcwd(buf, max) getwd (buf) |
| # endif |
| # define __readlink readlink |
| # define __set_errno(e) errno = (e) |
| # ifndef MAXSYMLINKS |
| # ifdef SYMLOOP_MAX |
| # define MAXSYMLINKS SYMLOOP_MAX |
| # else |
| # define MAXSYMLINKS 20 |
| # endif |
| # endif |
| #endif |
| |
| #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT |
| # define DOUBLE_SLASH_IS_DISTINCT_ROOT 0 |
| #endif |
| |
| /* Define this independently so that stdint.h is not a prerequisite. */ |
| #ifndef SIZE_MAX |
| # define SIZE_MAX ((size_t) -1) |
| #endif |
| |
| #if !FUNC_REALPATH_WORKS || defined _LIBC |
| |
| static void |
| alloc_failed (void) |
| { |
| #if defined _WIN32 && ! defined __CYGWIN__ |
| /* Avoid errno problem without using the malloc or realloc modules; see: |
| https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html */ |
| errno = ENOMEM; |
| #endif |
| } |
| |
| /* 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; |
| size_t prefix_len; |
| |
| 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 = 8192; |
| #endif |
| |
| if (resolved == NULL) |
| { |
| rpath = malloc (path_max); |
| if (rpath == NULL) |
| { |
| alloc_failed (); |
| return NULL; |
| } |
| } |
| else |
| rpath = resolved; |
| rpath_limit = rpath + path_max; |
| |
| /* This is always zero for Posix hosts, but can be 2 for MS-Windows |
| and MS-DOS X:/foo/bar file names. */ |
| prefix_len = FILE_SYSTEM_PREFIX_LEN (name); |
| |
| if (!IS_ABSOLUTE_FILE_NAME (name)) |
| { |
| if (!__getcwd (rpath, path_max)) |
| { |
| rpath[0] = '\0'; |
| goto error; |
| } |
| dest = strchr (rpath, '\0'); |
| start = name; |
| prefix_len = FILE_SYSTEM_PREFIX_LEN (rpath); |
| } |
| else |
| { |
| dest = rpath; |
| if (prefix_len) |
| { |
| memcpy (rpath, name, prefix_len); |
| dest += prefix_len; |
| } |
| *dest++ = '/'; |
| if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
| { |
| if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len) |
| *dest++ = '/'; |
| *dest = '\0'; |
| } |
| start = name + prefix_len; |
| } |
| |
| for (end = start; *start; start = end) |
| { |
| #ifdef _LIBC |
| struct stat64 st; |
| #else |
| struct stat st; |
| #endif |
| |
| /* Skip sequence of multiple path-separators. */ |
| while (ISSLASH (*start)) |
| ++start; |
| |
| /* Find end of path component. */ |
| for (end = start; *end && !ISSLASH (*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 + prefix_len + 1) |
| for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) |
| continue; |
| if (DOUBLE_SLASH_IS_DISTINCT_ROOT |
| && dest == rpath + 1 && !prefix_len |
| && ISSLASH (*dest) && !ISSLASH (dest[1])) |
| dest++; |
| } |
| else |
| { |
| size_t new_size; |
| |
| if (!ISSLASH (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 + prefix_len + 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) |
| { |
| alloc_failed (); |
| goto error; |
| } |
| rpath = new_rpath; |
| rpath_limit = rpath + new_size; |
| |
| dest = rpath + dest_offset; |
| } |
| |
| #ifdef _LIBC |
| dest = __mempcpy (dest, start, end - start); |
| #else |
| memcpy (dest, start, end - start); |
| dest += end - start; |
| #endif |
| *dest = '\0'; |
| |
| /* FIXME: if lstat fails with errno == EOVERFLOW, |
| the entry exists. */ |
| #ifdef _LIBC |
| if (__lxstat64 (_STAT_VER, rpath, &st) < 0) |
| #else |
| if (lstat (rpath, &st) < 0) |
| #endif |
| goto error; |
| |
| if (S_ISLNK (st.st_mode)) |
| { |
| char *buf; |
| size_t len; |
| ssize_t n; |
| |
| if (++num_links > MAXSYMLINKS) |
| { |
| __set_errno (ELOOP); |
| goto error; |
| } |
| |
| buf = malloca (path_max); |
| if (!buf) |
| { |
| __set_errno (ENOMEM); |
| goto error; |
| } |
| |
| n = __readlink (rpath, buf, path_max - 1); |
| if (n < 0) |
| { |
| int saved_errno = errno; |
| freea (buf); |
| __set_errno (saved_errno); |
| goto error; |
| } |
| buf[n] = '\0'; |
| |
| if (!extra_buf) |
| { |
| extra_buf = malloca (path_max); |
| if (!extra_buf) |
| { |
| freea (buf); |
| __set_errno (ENOMEM); |
| goto error; |
| } |
| } |
| |
| len = strlen (end); |
| /* Check that n + len + 1 doesn't overflow and is <= path_max. */ |
| if (n >= SIZE_MAX - len || n + len >= path_max) |
| { |
| freea (buf); |
| __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 (IS_ABSOLUTE_FILE_NAME (buf)) |
| { |
| size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); |
| |
| if (pfxlen) |
| memcpy (rpath, buf, pfxlen); |
| dest = rpath + pfxlen; |
| *dest++ = '/'; /* It's an absolute symlink */ |
| if (DOUBLE_SLASH_IS_DISTINCT_ROOT) |
| { |
| if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen) |
| *dest++ = '/'; |
| *dest = '\0'; |
| } |
| /* Install the new prefix to be in effect hereafter. */ |
| prefix_len = pfxlen; |
| } |
| else |
| { |
| /* Back up to previous component, ignore if at root |
| already: */ |
| if (dest > rpath + prefix_len + 1) |
| for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) |
| continue; |
| if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 |
| && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len) |
| dest++; |
| } |
| } |
| else if (!S_ISDIR (st.st_mode) && *end != '\0') |
| { |
| __set_errno (ENOTDIR); |
| goto error; |
| } |
| } |
| } |
| if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1])) |
| --dest; |
| if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len |
| && ISSLASH (*dest) && !ISSLASH (dest[1])) |
| dest++; |
| *dest = '\0'; |
| |
| if (extra_buf) |
| freea (extra_buf); |
| |
| return rpath; |
| |
| error: |
| { |
| int saved_errno = errno; |
| if (extra_buf) |
| freea (extra_buf); |
| if (resolved == NULL) |
| free (rpath); |
| __set_errno (saved_errno); |
| } |
| return NULL; |
| } |
| versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); |
| #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */ |
| |
| |
| #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) |
| |
| #else |
| |
| /* This declaration is solely to ensure that after preprocessing |
| this file is never empty. */ |
| typedef int dummy; |
| |
| #endif |
