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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 */
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