Resync new repository with old repo r5166

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5153 42af7a65-404d-4744-a932-0658087f49c3
2026-11-05 06:21:35 +08:00 · 2012-09-17 18:18:44 +00:00
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+/****************************************************************************
+ * sched/env_clearenv.c
+ *
+ *   Copyright (C) 2007, 2009 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <errno.h>
+#include "os_internal.h"
+#include "env_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: env_release
+ *
+ * Description:
+ *   The env_release() function clears the environment of all name-value
+ *   pairs and sets the value of the external variable environ to NULL.
+ *
+ * Parameters:
+ *   ptcb Identifies the TCB containing the environment structure
+ *
+ * Return Value:
+ *   zero on success
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler
+ *
+ ****************************************************************************/
+
+int env_release(FAR _TCB *ptcb)
+{
+  int ret = OK;
+
+  if (!ptcb)
+    {
+      ret = -EINVAL;
+    }
+  else
+    {
+      FAR environ_t *envp;
+
+      /* Examine the environ data in the TCB.  Preemption is disabled because the
+       * the environment could be shared among threads.
+       */
+
+      sched_lock();
+      envp = ptcb->envp;
+      if (ptcb->envp)
+        {
+          /* Check the reference count on the environment structure */
+
+          if ( envp->ev_crefs <= 1)
+            {
+              /* Decrementing the reference count will destroy the environment */
+
+              sched_free( envp ); /* plain free() should be fine here */
+            }
+          else
+            {
+              /* The environment will persist after decrementing the reference
+               * count */
+
+              envp->ev_crefs--;
+            }
+
+          /* In any case, the environment is no longer accessible on this thread */
+
+          ptcb->envp = NULL;
+        }
+
+      sched_unlock();
+    }
+
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+