Filesystem: Reject removal of root nodes

Reject the removal of file system instance root nodes in rmdir() and
unlink() and return the EBUSY error status.  File system instances can
be removed with unmount().  Remove root node special cases in IMFS,
DOSFS, and RFS.

2 files changed, 14 insertions, 3 deletions

diff --git a/cpukit/libcsupport/src/rmdir.c b/cpukit/libcsupport/src/rmdir.c
index 4e7baf5e39..f2bc16e516 100644
--- a/cpukit/libcsupport/src/rmdir.c
+++ b/cpukit/libcsupport/src/rmdir.c
@@ -38,7 +38,12 @@ int rmdir( const char *path )
   rtems_filesystem_node_types_t type = (*ops->node_type_h)( currentloc );
 
   if ( type == RTEMS_FILESYSTEM_DIRECTORY ) {
-    rv = (*ops->rmnod_h)( &parentloc, currentloc );
+    if ( !rtems_filesystem_location_is_root( currentloc ) ) {
+      rv = (*ops->rmnod_h)( &parentloc, currentloc );
+    } else {
+      rtems_filesystem_eval_path_error( &ctx, EBUSY );
+      rv = -1;
+    }
   } else {
     rtems_filesystem_eval_path_error( &ctx, ENOTDIR );
     rv = -1;
diff --git a/cpukit/libcsupport/src/unlink.c b/cpukit/libcsupport/src/unlink.c
index 9817ad9611..2a3b1c75a8 100644
--- a/cpukit/libcsupport/src/unlink.c
+++ b/cpukit/libcsupport/src/unlink.c
@@ -34,9 +34,15 @@ int unlink( const char *path )
       &parentloc,
       parent_eval_flags
     );
-  const rtems_filesystem_operations_table *ops = currentloc->mt_entry->ops;
 
-  rv = (*ops->rmnod_h)( &parentloc, currentloc );
+  if ( !rtems_filesystem_location_is_root( currentloc ) ) {
+    const rtems_filesystem_operations_table *ops = currentloc->mt_entry->ops;
+
+    rv = (*ops->rmnod_h)( &parentloc, currentloc );
+  } else {
+    rtems_filesystem_eval_path_error( &ctx, EBUSY );
+    rv = -1;
+  }
 
   rtems_filesystem_eval_path_cleanup_with_parent( &ctx, &parentloc );