--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/realpath.c	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,200 @@
+/*
+ * realpath.c -- canonicalize pathname by removing symlinks
+ * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
+ *
+
+This file is part of XEmacs.
+
+XEmacs 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, or (at your option) any
+later version.
+
+XEmacs 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 XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with: Not in FSF. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/types.h>
+#if defined(HAVE_UNISTD_H) || defined(STDC_HEADERS)
+#include <unistd.h>
+#endif
+#include <stdio.h>
+#include <string.h>
+#ifdef _POSIX_VERSION
+#include <limits.h>			/* for PATH_MAX */
+#else
+#include <sys/param.h>			/* for MAXPATHLEN */
+#endif
+#include <errno.h>
+#ifndef STDC_HEADERS
+extern int errno;
+#endif
+
+#include <sys/stat.h>			/* for S_IFLNK */
+
+#ifndef PATH_MAX
+#ifdef _POSIX_VERSION
+#define PATH_MAX _POSIX_PATH_MAX
+#else
+#ifdef MAXPATHLEN
+#define PATH_MAX MAXPATHLEN
+#else
+#define PATH_MAX 1024
+#endif
+#endif
+#endif
+
+#define MAX_READLINKS 32
+
+#ifdef __STDC__
+char *realpath(const char *path, char resolved_path [])
+#else
+char *realpath(path, resolved_path)
+const char *path;
+char resolved_path [];
+#endif
+{
+  char copy_path[PATH_MAX];
+  char link_path[PATH_MAX];
+  char *new_path = resolved_path;
+  char *max_path;
+  int readlinks = 0;
+  int n;
+
+  /* Make a copy of the source path since we may need to modify it. */
+  strcpy(copy_path, path);
+  path = copy_path;
+  max_path = copy_path + PATH_MAX - 2;
+  /* If it's a relative pathname use getwd for starters. */
+  if (*path != '/')
+    {
+#ifdef HAVE_GETCWD
+      getcwd(new_path, PATH_MAX - 1);
+#else
+      getwd(new_path);
+#endif
+      new_path += strlen(new_path);
+      if (new_path[-1] != '/')
+	*new_path++ = '/';
+    }
+  else
+    {
+      *new_path++ = '/';
+      path++;
+    }
+
+  /* Expand each slash-separated pathname component. */
+  while (*path != '\0')
+    {
+      /* Ignore stray "/". */
+      if (*path == '/')
+	{
+	  path++;
+	  continue;
+	}
+
+      if (*path == '.')
+	{
+	  /* Ignore ".". */
+	  if (path[1] == '\0' || path[1] == '/')
+	    {
+	      path++;
+	      continue;
+	    }
+
+	  if (path[1] == '.')
+	    {
+	      if (path[2] == '\0' || path[2] == '/')
+		{
+		  path += 2;
+
+		  /* Ignore ".." at root. */
+		  if (new_path == resolved_path + 1)
+		    continue;
+
+		  /* Handle ".." by backing up. */
+		  while ((--new_path)[-1] != '/')
+		    ;
+		  continue;
+		}
+	    }
+	}
+
+      /* Safely copy the next pathname component. */
+      while (*path != '\0' && *path != '/')
+	{
+	  if (path > max_path)
+	    {
+	      errno = ENAMETOOLONG;
+	      return NULL;
+	    }
+	  *new_path++ = *path++;
+	}
+
+#ifdef S_IFLNK
+      /* See if latest pathname component is a symlink. */
+      *new_path = '\0';
+      n = readlink(resolved_path, link_path, PATH_MAX - 1);
+
+      if (n < 0)
+	{
+	  /* EINVAL means the file exists but isn't a symlink. */
+	  if (errno != EINVAL)
+	    return NULL;
+	}
+      else
+	{
+	  /* Protect against infinite loops. */
+	  if (readlinks++ > MAX_READLINKS)
+	    {
+	      errno = ELOOP;
+	      return NULL;
+	    }
+
+	  /* Note: readlink doesn't add the null byte. */
+	  link_path[n] = '\0';
+
+	  if (*link_path == '/')
+	    /* Start over for an absolute symlink. */
+	    new_path = resolved_path;
+	  else
+	    /* Otherwise back up over this component. */
+	    while (*(--new_path) != '/')
+	      ;
+
+	  /* Safe sex check. */
+	  if (strlen(path) + n >= PATH_MAX)
+	    {
+	      errno = ENAMETOOLONG;
+	      return NULL;
+	    }
+
+	  /* Insert symlink contents into path. */
+	  strcat(link_path, path);
+	  strcpy(copy_path, link_path);
+	  path = copy_path;
+	}
+#endif /* S_IFLNK */
+      *new_path++ = '/';
+    }
+
+  /* Delete trailing slash but don't whomp a lone slash. */
+  if (new_path != resolved_path + 1 && new_path[-1] == '/')
+    new_path--;
+
+  /* Make sure it's null terminated. */
+  *new_path = '\0';
+  return resolved_path;
+}