--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libiberty/lrealpath.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,157 @@
+/* Libiberty realpath.  Like realpath, but more consistent behavior.
+   Based on gdb_realpath from GDB.
+
+   Copyright 2003 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 */
+# endif
+#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 we don't have realpath, we assume we
+     don't have symlinks and just canonicalize to a Windows absolute
+     path.  GetFullPath converts ../ and ./ in relative paths to
+     absolute paths, filling in current drive if one is not given
+     or using the current directory of a specified drive (eg, "E:foo").
+     It also converts all forward slashes to back slashes.  */
+#if defined (_WIN32)
+  {
+    char buf[MAX_PATH];
+    char* basename;
+    DWORD len = GetFullPathName (filename, MAX_PATH, buf, &basename);
+    if (len == 0 || len > MAX_PATH - 1)
+      return strdup (filename);
+    else
+      {
+	/* The file system is case-preserving but case-insensitive,
+	   Canonicalize to lowercase, using the codepage associated
+	   with the process locale.  */
+        CharLowerBuff (buf, len);
+        return strdup (buf);
+      }
+  }
+#endif
+
+  /* This system is a lost cause, just duplicate the filename.  */
+  return strdup (filename);
+}