NuttX RTOS

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 165 insertions, 0 deletions

diff --git a/nuttx/sched/task_delete.c b/nuttx/sched/task_delete.c
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+/************************************************************
+ * task_delete.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <sys/types.h>
+#include <sched.h>
+#include <nuttx/os_external.h>
+#include "os_internal.h"
+#include "sig_internal.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Type Declarations
+ ************************************************************/
+
+/************************************************************
+ * Global Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Function Prototypes
+ ************************************************************/
+
+/************************************************************
+ * Private Functions
+ ************************************************************/
+
+/************************************************************
+ * Public Functions
+ ************************************************************/
+
+/************************************************************
+ * Name: task_delete
+ *
+ * Description:
+ *   This function causes a specified task to cease to exist.
+ *   Its  stack and TCB will be deallocated.  This function
+ *   is the companion to task_create().
+ *
+ * Inputs:
+ *   pid - The task ID of the task to delete.  A pid of zero
+ *         signifies the calling task.
+ *
+ * Return Value:
+ *   OK on success; or ERROR on failure
+ *
+ *   This function can fail if the provided pid does not
+ *   correspond to a task (errno is not set)
+ *
+ ************************************************************/
+
+STATUS task_delete(pid_t pid)
+{
+  _TCB  *rtcb;
+  _TCB  *dtcb;
+  uint32 saved_state;
+  STATUS ret = ERROR;
+
+   /* Check if the task to delete is the calling task */
+
+   rtcb = (_TCB*)g_readytorun.head;
+   if (pid == 0 || pid == rtcb->pid)
+     {
+       /* If it is, then what we really wanted to do was exit.
+        * Note that we don't bother to unlock the TCB since
+        * it will be going away.
+        */
+
+       exit(EXIT_SUCCESS);
+     }
+
+  /* Make sure the task does not become ready-to-run while
+   * we are futzing with its TCB by locking ourselves as the
+   * executing task.
+   *
+   * Frist, find for the TCB associated with matching pid 
+   */
+
+   dtcb = sched_gettcb(pid);
+   if (!dtcb)
+     {
+        /* This pid does not correspond to any known task */
+
+        sched_unlock();
+        return ERROR;
+     }
+
+  /* Verify our internal sanity */
+
+  if (dtcb->task_state == TSTATE_TASK_RUNNING ||
+      dtcb->task_state >= NUM_TASK_STATES)
+    {
+      sched_unlock();
+      PANIC(OSERR_BADDELETESTATE);
+    }
+
+  saved_state = irqsave();
+
+  /* Inform the instrumentation layer that the task has stopped */
+
+  sched_note_stop(dtcb);
+
+  /* Remove the task from the OS's tasks lists. */
+
+  dq_rem((dq_entry_t*)dtcb, g_tasklisttable[dtcb->task_state].list);
+  dtcb->task_state = TSTATE_TASK_INVALID;
+  irqrestore(saved_state);
+
+  /* At this point, the TCB should no longer be accessible to the system */
+
+  sched_unlock();
+
+  /* Deallocate anything left in the TCB's queues */
+
+  sig_cleanup(dtcb); /* Deallocate Signal lists */
+
+  /* Deallocate its TCB */
+
+  sched_releasetcb(dtcb);
+  return ret;
+}