IMFS: Reference counting for nodes

The introduction of reference counting of nodes avoids the removal of
open nodes and potential usage of freed memory.

16 files changed, 84 insertions, 126 deletions

diff --git a/cpukit/libfs/src/imfs/deviceio.c b/cpukit/libfs/src/imfs/deviceio.c
index 69f409e472..c4e7a921ff 100644
--- a/cpukit/libfs/src/imfs/deviceio.c
+++ b/cpukit/libfs/src/imfs/deviceio.c
@@ -80,8 +80,6 @@ int device_close(
     (void *) &args
   );
 
-  IMFS_check_node_remove( the_jnode );
-
   return rtems_deviceio_errno( status );
 }
 
diff --git a/cpukit/libfs/src/imfs/fifoimfs_init.c b/cpukit/libfs/src/imfs/fifoimfs_init.c
index d2af7af8e5..966e9e1dde 100644
--- a/cpukit/libfs/src/imfs/fifoimfs_init.c
+++ b/cpukit/libfs/src/imfs/fifoimfs_init.c
@@ -36,8 +36,8 @@ const rtems_filesystem_operations_table fifoIMFS_ops = {
   .rmnod_h = IMFS_rmnod,
   .fchmod_h = IMFS_fchmod,
   .chown_h = IMFS_chown,
-  .clonenod_h = rtems_filesystem_default_clonenode,
-  .freenod_h = rtems_filesystem_default_freenode,
+  .clonenod_h = IMFS_node_clone,
+  .freenod_h = IMFS_node_free,
   .mount_h = IMFS_mount,
   .fsmount_me_h = fifoIMFS_initialize,
   .unmount_h = IMFS_unmount,
diff --git a/cpukit/libfs/src/imfs/imfs.h b/cpukit/libfs/src/imfs/imfs.h
index c2d95f0f8e..e9be053c20 100644
--- a/cpukit/libfs/src/imfs/imfs.h
+++ b/cpukit/libfs/src/imfs/imfs.h
@@ -166,6 +166,7 @@ struct IMFS_jnode_tt {
   IMFS_jnode_t       *Parent;                /* Parent node */
   char                name[IMFS_NAME_MAX+1]; /* "basename" */
   mode_t              st_mode;               /* File mode */
+  unsigned short      reference_count;
   nlink_t             st_nlink;              /* Link count */
   ino_t               st_ino;                /* inode */
 
@@ -274,6 +275,11 @@ extern void IMFS_dump( void );
  */
 extern int IMFS_memfile_maximum_size( void );
 
+extern void IMFS_node_destroy( IMFS_jnode_t *node );
+
+extern int IMFS_node_clone( rtems_filesystem_location_info_t *loc );
+
+extern void IMFS_node_free( const rtems_filesystem_location_info_t *loc );
 
 extern rtems_filesystem_node_types_t IMFS_node_type(
   const rtems_filesystem_location_info_t *loc
@@ -353,10 +359,6 @@ extern int imfs_dir_open(
   mode_t         mode             /* IN  */
 );
 
-extern int imfs_dir_close(
-  rtems_libio_t *iop             /* IN  */
-);
-
 extern ssize_t imfs_dir_read(
   rtems_libio_t *iop,              /* IN  */
   void          *buffer,           /* IN  */
@@ -376,10 +378,6 @@ extern int memfile_open(
   mode_t         mode             /* IN  */
 );
 
-extern int memfile_close(
-  rtems_libio_t *iop             /* IN  */
-);
-
 extern ssize_t memfile_read(
   rtems_libio_t *iop,             /* IN  */
   void          *buffer,          /* IN  */
@@ -476,19 +474,22 @@ extern int IMFS_rename(
   size_t namelen
 );
 
-extern void IMFS_create_orphan(
-  IMFS_jnode_t *jnode
-);
-
-extern void IMFS_check_node_remove(
-  IMFS_jnode_t *jnode
-);
-
 extern int IMFS_rmnod(
   const rtems_filesystem_location_info_t *parentloc,
   const rtems_filesystem_location_info_t *loc
 );
 
+/*
+ *  Turn on IMFS assertions when RTEMS_DEBUG is defined.
+ */
+#ifdef RTEMS_DEBUG
+  #include <assert.h>
+
+  #define IMFS_assert(_x) assert(_x)
+#else
+  #define IMFS_assert(_x)
+#endif
+
 static inline void IMFS_add_to_directory(
   IMFS_jnode_t *dir,
   IMFS_jnode_t *node
@@ -500,21 +501,11 @@ static inline void IMFS_add_to_directory(
 
 static inline void IMFS_remove_from_directory( IMFS_jnode_t *node )
 {
+  IMFS_assert( node->Parent != NULL );
   node->Parent = NULL;
   rtems_chain_extract_unprotected( &node->Node );
 }
 
-/*
- *  Turn on IMFS assertions when RTEMS_DEBUG is defined.
- */
-#ifdef RTEMS_DEBUG
-  #include <assert.h>
-
-  #define IMFS_assert(_x) assert(_x)
-#else
-  #define IMFS_assert(_x)
-#endif
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/cpukit/libfs/src/imfs/imfs_creat.c b/cpukit/libfs/src/imfs/imfs_creat.c
index caf82be250..2fe3c7dba1 100644
--- a/cpukit/libfs/src/imfs/imfs_creat.c
+++ b/cpukit/libfs/src/imfs/imfs_creat.c
@@ -123,6 +123,7 @@ IMFS_jnode_t *IMFS_allocate_node(
   /*
    *  Fill in the basic information
    */
+  node->reference_count = 1;
   node->st_nlink = 1;
   node->type     = type;
   memcpy( node->name, name, namelen );
diff --git a/cpukit/libfs/src/imfs/imfs_directory.c b/cpukit/libfs/src/imfs/imfs_directory.c
index fc687e4331..3bbbec22fb 100644
--- a/cpukit/libfs/src/imfs/imfs_directory.c
+++ b/cpukit/libfs/src/imfs/imfs_directory.c
@@ -127,30 +127,6 @@ ssize_t imfs_dir_read(
    return bytes_transferred;
 }
 
-
-
-/*
- *  imfs_dir_close
- *
- *  This routine will be called by the generic close routine to cleanup any
- *  resources that have been allocated for the management of the file
- */
-
-int imfs_dir_close(
-  rtems_libio_t  *iop
-)
-{
-  /*
-   *  The generic close routine handles the deallocation of the file control
-   *  and associated memory. At present the imfs_dir_close simply
-   *  returns a successful completion status.
-   */
-
-  return 0;
-}
-
-
-
 /*
  *  imfs_dir_lseek
  *
diff --git a/cpukit/libfs/src/imfs/imfs_eval.c b/cpukit/libfs/src/imfs/imfs_eval.c
index 33e7e36520..5b1ccfb989 100644
--- a/cpukit/libfs/src/imfs/imfs_eval.c
+++ b/cpukit/libfs/src/imfs/imfs_eval.c
@@ -154,6 +154,8 @@ static rtems_filesystem_eval_path_generic_status IMFS_eval_token(
           IMFS_is_mount_point( entry );
 
         if ( fs_root_ptr == NULL ) {
+          --dir->reference_count;
+          ++entry->reference_count;
           currentloc->node_access = entry;
           IMFS_Set_handlers( currentloc );
 
diff --git a/cpukit/libfs/src/imfs/imfs_fifo.c b/cpukit/libfs/src/imfs/imfs_fifo.c
index 985275049a..dc623629b6 100644
--- a/cpukit/libfs/src/imfs/imfs_fifo.c
+++ b/cpukit/libfs/src/imfs/imfs_fifo.c
@@ -50,9 +50,6 @@ static int IMFS_fifo_close(
 
   pipe_release(&JNODE2PIPE(jnode), iop);
 
-  iop->flags &= ~LIBIO_FLAGS_OPEN;
-  IMFS_check_node_remove(jnode);
-
   IMFS_FIFO_RETURN(err);
 }
 
diff --git a/cpukit/libfs/src/imfs/imfs_fsunmount.c b/cpukit/libfs/src/imfs/imfs_fsunmount.c
index 49ade1bab9..6f9388ea86 100644
--- a/cpukit/libfs/src/imfs/imfs_fsunmount.c
+++ b/cpukit/libfs/src/imfs/imfs_fsunmount.c
@@ -63,8 +63,9 @@ void IMFS_fsunmount(
 
      if ( jnode->type != IMFS_DIRECTORY || jnode_has_no_children( jnode ) ) {
         result = IMFS_rmnod( NULL, &loc );
-        if (result != 0)
-	  rtems_fatal_error_occurred(0xdeadbeef);
+        if ( result != 0 )
+	  rtems_fatal_error_occurred( 0xdeadbeef );
+        IMFS_node_destroy( jnode );
         jnode = next;
      }
      if ( jnode != NULL ) {
diff --git a/cpukit/libfs/src/imfs/imfs_handlers_directory.c b/cpukit/libfs/src/imfs/imfs_handlers_directory.c
index dfda4fc2cb..b18f2ab6b9 100644
--- a/cpukit/libfs/src/imfs/imfs_handlers_directory.c
+++ b/cpukit/libfs/src/imfs/imfs_handlers_directory.c
@@ -23,7 +23,7 @@
 
 const rtems_filesystem_file_handlers_r IMFS_directory_handlers = {
   imfs_dir_open,
-  imfs_dir_close,
+  rtems_filesystem_default_close,
   imfs_dir_read,
   rtems_filesystem_default_write,
   rtems_filesystem_default_ioctl,
diff --git a/cpukit/libfs/src/imfs/imfs_handlers_memfile.c b/cpukit/libfs/src/imfs/imfs_handlers_memfile.c
index e179eabf44..10cba9477b 100644
--- a/cpukit/libfs/src/imfs/imfs_handlers_memfile.c
+++ b/cpukit/libfs/src/imfs/imfs_handlers_memfile.c
@@ -23,7 +23,7 @@
 
 const rtems_filesystem_file_handlers_r IMFS_memfile_handlers = {
   memfile_open,
-  memfile_close,
+  rtems_filesystem_default_close,
   memfile_read,
   memfile_write,
   memfile_ioctl,
diff --git a/cpukit/libfs/src/imfs/imfs_init.c b/cpukit/libfs/src/imfs/imfs_init.c
index 2a7d890a09..8b4db45019 100644
--- a/cpukit/libfs/src/imfs/imfs_init.c
+++ b/cpukit/libfs/src/imfs/imfs_init.c
@@ -34,8 +34,8 @@ const rtems_filesystem_operations_table IMFS_ops = {
   .rmnod_h = IMFS_rmnod,
   .fchmod_h = IMFS_fchmod,
   .chown_h = IMFS_chown,
-  .clonenod_h = rtems_filesystem_default_clonenode,
-  .freenod_h = rtems_filesystem_default_freenode,
+  .clonenod_h = IMFS_node_clone,
+  .freenod_h = IMFS_node_free,
   .mount_h = IMFS_mount,
   .fsmount_me_h = IMFS_initialize,
   .unmount_h = IMFS_unmount,
diff --git a/cpukit/libfs/src/imfs/imfs_initsupp.c b/cpukit/libfs/src/imfs/imfs_initsupp.c
index 61ad6a70f2..042995b878 100644
--- a/cpukit/libfs/src/imfs/imfs_initsupp.c
+++ b/cpukit/libfs/src/imfs/imfs_initsupp.c
@@ -106,3 +106,41 @@ int IMFS_initialize_support(
 
   return 0;
 }
+
+int IMFS_node_clone( rtems_filesystem_location_info_t *loc )
+{
+  IMFS_jnode_t *node = loc->node_access;
+
+  ++node->reference_count;
+
+  return 0;
+}
+
+void IMFS_node_destroy( IMFS_jnode_t *node )
+{
+  IMFS_assert( node->reference_count == 0 );
+
+  switch ( node->type ) {
+    case IMFS_MEMORY_FILE:
+      IMFS_memfile_remove( node );
+      break;
+    case IMFS_SYM_LINK:
+      free( node->info.sym_link.name );
+      break;
+    default:
+      break;
+  }
+
+  free( node );
+}
+
+void IMFS_node_free( const rtems_filesystem_location_info_t *loc )
+{
+  IMFS_jnode_t *node = loc->node_access;
+
+  if ( node->reference_count == 1 ) {
+    IMFS_node_destroy( node );
+  } else {
+    --node->reference_count;
+  }
+}
diff --git a/cpukit/libfs/src/imfs/imfs_link.c b/cpukit/libfs/src/imfs/imfs_link.c
index 130c529d75..2684dbe64f 100644
--- a/cpukit/libfs/src/imfs/imfs_link.c
+++ b/cpukit/libfs/src/imfs/imfs_link.c
@@ -30,12 +30,15 @@ int IMFS_link(
 {
   IMFS_types_union   info;
   IMFS_jnode_t      *new_node;
+  IMFS_jnode_t      *target;
+
+  target = targetloc->node_access;
+  info.hard_link.link_node = target;
 
   /*
    *  Verify this node can be linked to.
    */
-  info.hard_link.link_node = targetloc->node_access;
-  if ( info.hard_link.link_node->st_nlink >= LINK_MAX )
+  if ( target->st_nlink >= LINK_MAX )
     rtems_set_errno_and_return_minus_one( EMLINK );
 
   /*
@@ -56,8 +59,9 @@ int IMFS_link(
   /*
    * Increment the link count of the node being pointed to.
    */
-  info.hard_link.link_node->st_nlink++;
-  IMFS_update_ctime( info.hard_link.link_node );
+  target->reference_count++;
+  target->st_nlink++;
+  IMFS_update_ctime( target );
 
   return 0;
 }
diff --git a/cpukit/libfs/src/imfs/imfs_rmnod.c b/cpukit/libfs/src/imfs/imfs_rmnod.c
index ae4d8fb92b..748a6f7365 100644
--- a/cpukit/libfs/src/imfs/imfs_rmnod.c
+++ b/cpukit/libfs/src/imfs/imfs_rmnod.c
@@ -23,44 +23,13 @@
 
 #include "imfs.h"
 
-#include <stdlib.h>
-
-void IMFS_create_orphan( IMFS_jnode_t *jnode )
-{
-  if ( jnode->Parent != NULL ) {
-    IMFS_remove_from_directory( jnode );
-  }
-
-  --jnode->st_nlink;
-
-  IMFS_update_ctime( jnode );
-}
-
-void IMFS_check_node_remove( IMFS_jnode_t *jnode )
-{
-  if ( jnode->st_nlink < 1 ) {
-    switch ( jnode->type ) {
-      case IMFS_MEMORY_FILE:
-        IMFS_memfile_remove( jnode );
-        break;
-      case IMFS_SYM_LINK:
-        free( jnode->info.sym_link.name );
-        break;
-      default:
-        break;
-    }
-
-    free( jnode );
-  }
-}
-
 static int IMFS_rmnod_directory(
   const rtems_filesystem_location_info_t *parentloc,
   const rtems_filesystem_location_info_t *loc
 )
 {
-  IMFS_jnode_t *node = loc->node_access;
   int rv = 0;
+  IMFS_jnode_t *node = loc->node_access;
 
   if ( !rtems_chain_is_empty( &node->info.directory.Entries ) ) {
     errno = ENOTEMPTY;
@@ -120,8 +89,11 @@ int IMFS_rmnod(
   }
 
   if ( rv == 0 ) {
-    IMFS_create_orphan( node );
-    IMFS_check_node_remove( node );
+    --node->reference_count;
+    --node->st_nlink;
+    if ( node->Parent != NULL ) {
+      IMFS_remove_from_directory( node );
+    }
   }
 
   return rv;
diff --git a/cpukit/libfs/src/imfs/memfile.c b/cpukit/libfs/src/imfs/memfile.c
index 65810c0bca..fed8914235 100644
--- a/cpukit/libfs/src/imfs/memfile.c
+++ b/cpukit/libfs/src/imfs/memfile.c
@@ -114,28 +114,6 @@ int memfile_open(
 }
 
 /*
- *  memfile_close
- *
- *  This routine processes the close() system call.  Note that there is
- *  nothing to flush or memory to free at this point.
- */
-int memfile_close(
-  rtems_libio_t *iop
-)
-{
-  IMFS_jnode_t   *the_jnode;
-
-  the_jnode = iop->pathinfo.node_access;
-
-  if (iop->flags & LIBIO_FLAGS_APPEND)
-    iop->offset = the_jnode->info.file.size;
-
-  IMFS_check_node_remove( the_jnode );
-
-  return 0;
-}
-
-/*
  *  memfile_read
  *
  *  This routine processes the read() system call.
diff --git a/cpukit/libfs/src/imfs/miniimfs_init.c b/cpukit/libfs/src/imfs/miniimfs_init.c
index a4db968e3c..af791f5a31 100644
--- a/cpukit/libfs/src/imfs/miniimfs_init.c
+++ b/cpukit/libfs/src/imfs/miniimfs_init.c
@@ -34,8 +34,8 @@ static const rtems_filesystem_operations_table miniIMFS_ops = {
   .rmnod_h = IMFS_rmnod,
   .fchmod_h = rtems_filesystem_default_fchmod,
   .chown_h = rtems_filesystem_default_chown,
-  .clonenod_h = rtems_filesystem_default_clonenode,
-  .freenod_h = rtems_filesystem_default_freenode,
+  .clonenod_h = IMFS_node_clone,
+  .freenod_h = IMFS_node_free,
   .mount_h = IMFS_mount,
   .fsmount_me_h = miniIMFS_initialize,
   .unmount_h = rtems_filesystem_default_unmount,