Added base version of file system infrastructure. This includes a major

overhaul of the RTEMS system call interface.  This base file system is
the "In-Memory File System" aka IMFS.

The design and implementation was done by the following people:

  + Joel Sherrill (joel@OARcorp.com)
  + Jennifer Averett (jennifer@OARcorp.com)
  + Steve "Mr Mount" Salitasc (salitasc@OARcorp.com)
  + Kerwin Wade (wade@OARcorp.com)

PROBLEMS
========
  + It is VERY likely that merging this will break the UNIX port.  This
    can/will be fixed.

  + There is likely some reentrancy/mutual exclusion needed.

  + Eventually, there should be a "mini-IMFS" description table to
    eliminate links, symlinks, etc to save memory.  All you need to
    have "classic RTEMS" functionality is technically directories
    and device IO.  All the rest could be left out to save memory.

c/src/lib/libc/eval.c

@@ -0,0 +1,74 @@
+/*
+ *  rtems_filesystem_evaluate_path()
+ *
+ *  Routine to seed the evaluate path routine.
+ *
+ *  COPYRIGHT (c) 1989-1998.
+ *  On-Line Applications Research Corporation (OAR).
+ *  Copyright assigned to U.S. Government, 1994.
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+#include <rtems.h>
+#include "libio_.h"
+
+int rtems_filesystem_evaluate_path(
+  const char                        *pathname,
+  int                                flags,
+  rtems_filesystem_location_info_t  *pathloc,
+  int                                follow_link
+)
+{
+  int                           i;
+  int                           result;
+  rtems_filesystem_node_types_t type;
+
+  /*
+   * Verify Input parameters.
+   */
+
+  if ( !pathname )
+    set_errno_and_return_minus_one( EFAULT );
+
+  if ( !pathloc )
+    set_errno_and_return_minus_one( EIO );       /* should never happen */
+  
+  /*
+   * Evaluate the path using the optable evalpath.
+   */
+
+  rtems_filesystem_get_start_loc( pathname, &i, pathloc );
+
+  result = (*pathloc->ops->evalpath)( &pathname[i], flags, pathloc );
+
+  /*
+   * Get the Node type and determine if you need to follow the link or
+   * not.
+   */
+
+  if ( follow_link ) {
+
+    if ( !pathloc->ops->node_type )
+      set_errno_and_return_minus_one( ENOTSUP );
+
+    type = (*pathloc->ops->node_type)( pathloc );
+
+    if ( ( type == RTEMS_FILESYSTEM_HARD_LINK ) ||
+         ( type == RTEMS_FILESYSTEM_SYM_LINK ) ) {
+
+        if ( !pathloc->ops->eval_link )
+          set_errno_and_return_minus_one( ENOTSUP );
+
+         result =  (*pathloc->ops->eval_link)( pathloc, flags );
+ 
+    }
+  }
+
+  return result;
+}
+