| /* Libiberty realpath. Like realpath, but more consistent behavior. |
| Based on gdb_realpath from GDB. |
| |
| Copyright (C) 2003-2024 Free Software Foundation, Inc. |
| |
| This file is part of the libiberty 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 2 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, write to the Free Software |
| Foundation, Inc., 51 Franklin Street - Fifth Floor, |
| Boston, MA 02110-1301, USA. */ |
| |
| /* |
| |
| @deftypefn Replacement {const char*} lrealpath (const char *@var{name}) |
| |
| Given a pointer to a string containing a pathname, returns a canonical |
| version of the filename. Symlinks will be resolved, and ``.'' and ``..'' |
| components will be simplified. The returned value will be allocated using |
| @code{malloc}, or @code{NULL} will be returned on a memory allocation error. |
| |
| @end deftypefn |
| |
| */ |
| |
| #include "config.h" |
| #include "ansidecl.h" |
| #include "libiberty.h" |
| |
| #ifdef HAVE_LIMITS_H |
| #include <limits.h> |
| #endif |
| #ifdef HAVE_STDLIB_H |
| #include <stdlib.h> |
| #endif |
| #ifdef HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| #ifdef HAVE_STRING_H |
| #include <string.h> |
| #endif |
| |
| /* On GNU libc systems the declaration is only visible with _GNU_SOURCE. */ |
| #if defined(HAVE_CANONICALIZE_FILE_NAME) \ |
| && defined(NEED_DECLARATION_CANONICALIZE_FILE_NAME) |
| extern char *canonicalize_file_name (const char *); |
| #endif |
| |
| #if defined(HAVE_REALPATH) |
| # if defined (PATH_MAX) |
| # define REALPATH_LIMIT PATH_MAX |
| # else |
| # if defined (MAXPATHLEN) |
| # define REALPATH_LIMIT MAXPATHLEN |
| # endif |
| # endif |
| #else |
| /* cygwin has realpath, so it won't get here. */ |
| # if defined (_WIN32) |
| # define WIN32_LEAN_AND_MEAN |
| # include <windows.h> /* for GetFullPathName/GetFinalPathNameByHandle/ |
| CreateFile/CloseHandle */ |
| # define WIN32_REPLACE_SLASHES(_ptr, _len) \ |
| for (unsigned i = 0; i != (_len); ++i) \ |
| if ((_ptr)[i] == '\\') (_ptr)[i] = '/'; |
| |
| # define WIN32_UNC_PREFIX "//?/UNC/" |
| # define WIN32_UNC_PREFIX_LEN (sizeof(WIN32_UNC_PREFIX)-1) |
| # define WIN32_IS_UNC_PREFIX(ptr) \ |
| (0 == memcmp(ptr, WIN32_UNC_PREFIX, WIN32_UNC_PREFIX_LEN)) |
| |
| # define WIN32_NON_UNC_PREFIX "//?/" |
| # define WIN32_NON_UNC_PREFIX_LEN (sizeof(WIN32_NON_UNC_PREFIX)-1) |
| # define WIN32_IS_NON_UNC_PREFIX(ptr) \ |
| (0 == memcmp(ptr, WIN32_NON_UNC_PREFIX, WIN32_NON_UNC_PREFIX_LEN)) |
| |
| /* Get full path name without symlinks resolution. |
| It also converts all forward slashes to back slashes. |
| */ |
| char* get_full_path_name(const char *filename) { |
| DWORD len; |
| char *buf, *ptr, *res; |
| |
| /* determining the required buffer size. |
| from the man: `If the lpBuffer buffer is too small to contain |
| the path, the return value is the size, in TCHARs, of the buffer |
| that is required to hold the path _and_the_terminating_null_character_` |
| */ |
| len = GetFullPathName(filename, 0, NULL, NULL); |
| |
| if ( len == 0 ) |
| return strdup(filename); |
| |
| buf = (char *)malloc(len); |
| |
| /* no point to check the result again */ |
| len = GetFullPathName(filename, len, buf, NULL); |
| buf[len] = 0; |
| |
| /* replace slashes */ |
| WIN32_REPLACE_SLASHES(buf, len); |
| |
| /* calculate offset based on prefix type */ |
| len = WIN32_IS_UNC_PREFIX(buf) |
| ? (WIN32_UNC_PREFIX_LEN - 2) |
| : WIN32_IS_NON_UNC_PREFIX(buf) |
| ? WIN32_NON_UNC_PREFIX_LEN |
| : 0 |
| ; |
| |
| ptr = buf + len; |
| if ( WIN32_IS_UNC_PREFIX(buf) ) { |
| ptr[0] = '/'; |
| ptr[1] = '/'; |
| } |
| |
| res = strdup(ptr); |
| |
| free(buf); |
| |
| return res; |
| } |
| |
| # if _WIN32_WINNT >= 0x0600 |
| |
| /* Get full path name WITH symlinks resolution. |
| It also converts all forward slashes to back slashes. |
| */ |
| char* get_final_path_name(HANDLE fh) { |
| DWORD len; |
| char *buf, *ptr, *res; |
| |
| /* determining the required buffer size. |
| from the man: `If the function fails because lpszFilePath is too |
| small to hold the string plus the terminating null character, |
| the return value is the required buffer size, in TCHARs. This |
| value _includes_the_size_of_the_terminating_null_character_`. |
| but in my testcase I have path with 26 chars, the function |
| returns 26 also, ie without the trailing zero-char... |
| */ |
| len = GetFinalPathNameByHandle( |
| fh |
| ,NULL |
| ,0 |
| ,FILE_NAME_NORMALIZED | VOLUME_NAME_DOS |
| ); |
| |
| if ( len == 0 ) |
| return NULL; |
| |
| len += 1; /* for zero-char */ |
| buf = (char *)malloc(len); |
| |
| /* no point to check the result again */ |
| len = GetFinalPathNameByHandle( |
| fh |
| ,buf |
| ,len |
| ,FILE_NAME_NORMALIZED | VOLUME_NAME_DOS |
| ); |
| buf[len] = 0; |
| |
| /* replace slashes */ |
| WIN32_REPLACE_SLASHES(buf, len); |
| |
| /* calculate offset based on prefix type */ |
| len = WIN32_IS_UNC_PREFIX(buf) |
| ? (WIN32_UNC_PREFIX_LEN - 2) |
| : WIN32_IS_NON_UNC_PREFIX(buf) |
| ? WIN32_NON_UNC_PREFIX_LEN |
| : 0 |
| ; |
| |
| ptr = buf + len; |
| if ( WIN32_IS_UNC_PREFIX(buf) ) { |
| ptr[0] = '/'; |
| ptr[1] = '/'; |
| } |
| |
| res = strdup(ptr); |
| |
| free(buf); |
| |
| return res; |
| } |
| |
| # endif // _WIN32_WINNT >= 0x0600 |
| |
| # endif // _WIN32 |
| #endif |
| |
| char * |
| lrealpath (const char *filename) |
| { |
| /* Method 1: The system has a compile time upper bound on a filename |
| path. Use that and realpath() to canonicalize the name. This is |
| the most common case. Note that, if there isn't a compile time |
| upper bound, you want to avoid realpath() at all costs. */ |
| #if defined(REALPATH_LIMIT) |
| { |
| char buf[REALPATH_LIMIT]; |
| const char *rp = realpath (filename, buf); |
| if (rp == NULL) |
| rp = filename; |
| return strdup (rp); |
| } |
| #endif /* REALPATH_LIMIT */ |
| |
| /* Method 2: The host system (i.e., GNU) has the function |
| canonicalize_file_name() which malloc's a chunk of memory and |
| returns that, use that. */ |
| #if defined(HAVE_CANONICALIZE_FILE_NAME) |
| { |
| char *rp = canonicalize_file_name (filename); |
| if (rp == NULL) |
| return strdup (filename); |
| else |
| return rp; |
| } |
| #endif |
| |
| /* Method 3: Now we're getting desperate! The system doesn't have a |
| compile time buffer size and no alternative function. Query the |
| OS, using pathconf(), for the buffer limit. Care is needed |
| though, some systems do not limit PATH_MAX (return -1 for |
| pathconf()) making it impossible to pass a correctly sized buffer |
| to realpath() (it could always overflow). On those systems, we |
| skip this. */ |
| #if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H) |
| { |
| /* Find out the max path size. */ |
| long path_max = pathconf ("/", _PC_PATH_MAX); |
| if (path_max > 0) |
| { |
| /* PATH_MAX is bounded. */ |
| char *buf, *rp, *ret; |
| buf = (char *) malloc (path_max); |
| if (buf == NULL) |
| return NULL; |
| rp = realpath (filename, buf); |
| ret = strdup (rp ? rp : filename); |
| free (buf); |
| return ret; |
| } |
| } |
| #endif |
| |
| /* The MS Windows method */ |
| #if defined (_WIN32) |
| { |
| char *res; |
| |
| /* For Windows Vista and greater */ |
| #if _WIN32_WINNT >= 0x0600 |
| |
| /* For some reason the function receives just empty `filename`, but not NULL. |
| What should we do in that case? |
| According to `strdup()` implementation |
| (https://elixir.bootlin.com/glibc/latest/source/string/strdup.c) |
| it will alloc 1 byte even for empty but non NULL string. |
| OK, will use `strdup()` for that case. |
| */ |
| if ( 0 == strlen(filename) ) |
| return strdup(filename); |
| |
| HANDLE fh = CreateFile( |
| filename |
| ,FILE_READ_ATTRIBUTES |
| ,FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE |
| ,NULL |
| ,OPEN_EXISTING |
| ,FILE_FLAG_BACKUP_SEMANTICS |
| ,NULL |
| ); |
| |
| if ( fh == INVALID_HANDLE_VALUE ) { |
| res = get_full_path_name(filename); |
| } else { |
| res = get_final_path_name(fh); |
| CloseHandle(fh); |
| |
| if ( !res ) |
| res = get_full_path_name(filename); |
| } |
| |
| #else |
| |
| /* For Windows XP */ |
| res = get_full_path_name(filename); |
| |
| #endif // _WIN32_WINNT >= 0x0600 |
| |
| return res; |
| } |
| #endif // _WIN32 |
| } |