IMFS: Add make generic node support

Generic nodes are an alternative to standard drivers in RTEMS.  The
handlers of a generic node are called with less overhead compared to the
standard driver operations.  The usage of file system node handlers
enable more features like support for fsync() and fdatasync().  The
generic nodes use the reference counting of the IMFS.  This provides
automatic node destruction when the last reference vanishes.

Extend type IMFS_types_union by new type IMFS_generic_t.

Extend enum IMFS_jnode_types_t by IMFS_GENERIC.

Add functions
 o IMFS_make_generic_node(),
 o IMFS_is_imfs_instance(),
 o IMFS_generic_get_context_by_node(),
 o IMFS_generic_get_context_by_location(), and
 o IMFS_generic_get_context_by_iop().

New test fstests/fsimfsgeneric01.

1 files changed, 108 insertions, 0 deletions

diff --git a/cpukit/libfs/src/imfs/imfs_make_generic_node.c b/cpukit/libfs/src/imfs/imfs_make_generic_node.c
new file mode 100644
index 0000000000..5b7a7d9cec
--- /dev/null
+++ b/cpukit/libfs/src/imfs/imfs_make_generic_node.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include "imfs.h"
+
+IMFS_jnode_t *IMFS_node_initialize_generic(
+  IMFS_jnode_t *node,
+  const IMFS_types_union *info
+)
+{
+  node->info.generic.context = info->generic.context;
+
+  return node;
+}
+
+bool IMFS_is_imfs_instance(
+  const rtems_filesystem_location_info_t *loc
+)
+{
+  const char *type = loc->mt_entry->type;
+
+  return strcmp(type, RTEMS_FILESYSTEM_TYPE_IMFS) == 0
+    || strcmp(type, RTEMS_FILESYSTEM_TYPE_MINIIMFS) == 0;
+}
+
+int IMFS_make_generic_node(
+  const char *path,
+  mode_t mode,
+  const IMFS_node_control *node_control,
+  void *context
+)
+{
+  int rv = 0;
+
+  mode &= ~rtems_filesystem_umask;
+
+  switch (mode & S_IFMT) {
+    case S_IFBLK:
+    case S_IFCHR:
+    case S_IFIFO:
+    case S_IFREG:
+      break;
+    default:
+      errno = EINVAL;
+      rv = -1;
+      break;
+  }
+  
+  if ( rv == 0 ) {
+    if ( node_control->imfs_type == IMFS_GENERIC ) {
+      rtems_filesystem_eval_path_context_t ctx;
+      int eval_flags = RTEMS_FS_FOLLOW_LINK
+        | RTEMS_FS_MAKE
+        | RTEMS_FS_EXCLUSIVE;
+      const rtems_filesystem_location_info_t *currentloc =
+        rtems_filesystem_eval_path_start( &ctx, path, eval_flags );
+
+      if ( IMFS_is_imfs_instance( currentloc ) ) {
+        IMFS_types_union info;
+        IMFS_jnode_t *new_node;
+
+        info.generic.context = context;
+        new_node = IMFS_create_node_with_control(
+          currentloc,
+          node_control,
+          rtems_filesystem_eval_path_get_token( &ctx ),
+          rtems_filesystem_eval_path_get_tokenlen( &ctx ),
+          mode,
+          &info
+        );
+
+        if ( new_node != NULL ) {
+          IMFS_jnode_t *parent = currentloc->node_access;
+
+          IMFS_update_ctime( parent );
+          IMFS_update_mtime( parent );
+        } else {
+          rv = -1;
+        }
+      } else {
+        rtems_filesystem_eval_path_error( &ctx, ENOTSUP );
+        rv = -1;
+      }
+
+      rtems_filesystem_eval_path_cleanup( &ctx );
+    } else {
+      errno = EINVAL;
+      rv = -1;
+    }
+  }
+
+  return rv;
+}