Add framework to support task groups

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5562 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 127 insertions, 0 deletions

diff --git a/nuttx/sched/group_leave.c b/nuttx/sched/group_leave.c
new file mode 100644
index 000000000..69a6ea8b2
--- /dev/null
+++ b/nuttx/sched/group_leave.c
@@ -0,0 +1,127 @@
+/*****************************************************************************
+ * sched/group_leave.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Included Files
+ *****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include "os_internal.h"
+
+#ifdef HAVE_TASK_GROUP
+
+/*****************************************************************************
+ * Pre-processor Definitions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Types
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Data
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Private Functions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Public Functions
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Name: group_leave
+ *
+ * Description:
+ *   Release a reference on a group.  This function is called when a task or
+ *   thread exits.  It decrements the reference count on the group.  If the
+ *   reference count decrements to zero, then it frees the group and all of
+ *   resources contained in the group.
+ *
+ * Parameters:
+ *   tcb - The TCB of the task that is exiting.
+ *
+ * Return Value:
+ *   None.
+ *
+ * Assumptions:
+ *   Called during task deletion in a safe context.  No special precautions
+ *   are required here.
+ *
+ *****************************************************************************/
+
+void group_leave(FAR _TCB *tcb)
+{
+  FAR struct task_group_s *group;
+
+  DEBUGASSERT(tcb);
+
+  /* Make sure that we have a group */
+
+  group = tcb->group;
+  if (group)
+    {
+      /* Would the reference count decrement to zero? */
+
+      if (group->tg_crefs > 1)
+        {
+          /* No.. just decrement the reference count and return */
+
+          group->tg_crefs--;
+        }
+      else
+        {
+          /* Yes.. Release all of the resource contained within the group */
+          /* Free all un-reaped child exit status */
+
+          task_removechildren(tcb);
+
+          /* Release the group container itself */
+
+          sched_free(group);
+        }
+
+      tcb->group = NULL;
+    }
+}
+
+#endif /* HAVE_TASK_GROUP */