forked from Archive/PX4-Autopilot
126 lines
3.9 KiB
C
126 lines
3.9 KiB
C
/****************************************************************************
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* sched/env_clearenv.c
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*
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* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#ifndef CONFIG_DISABLE_ENVIRON
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#include <sched.h>
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#include <errno.h>
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#include "os_internal.h"
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#include "env_internal.h"
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: env_release
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*
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* Description:
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* The env_release() function clears the environment of all name-value
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* pairs and sets the value of the external variable environ to NULL.
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*
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* Parameters:
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* ptcb Identifies the TCB containing the environment structure
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*
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* Return Value:
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* zero on success
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*
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* Assumptions:
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* Not called from an interrupt handler
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*
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****************************************************************************/
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int env_release(FAR _TCB *ptcb)
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{
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int ret = OK;
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if (!ptcb)
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{
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ret = -EINVAL;
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}
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else
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{
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FAR environ_t *envp;
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/* Examine the environ data in the TCB. Preemption is disabled because the
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* the environment could be shared among threads.
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*/
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sched_lock();
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envp = ptcb->envp;
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if (ptcb->envp)
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{
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/* Check the reference count on the environment structure */
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if (envp->ev_crefs <= 1)
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{
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/* Decrementing the reference count will destroy the environment */
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sched_free(envp);
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}
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else
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{
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/* The environment will persist after decrementing the reference
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* count */
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envp->ev_crefs--;
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}
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/* In any case, the environment is no longer accessible on this thread */
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ptcb->envp = NULL;
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}
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sched_unlock();
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}
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return ret;
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}
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#endif /* CONFIG_DISABLE_ENVIRON */
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