forked from Archive/PX4-Autopilot
125 lines
4.2 KiB
C
125 lines
4.2 KiB
C
/****************************************************************************
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* sched/env_findvar.c
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*
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* Copyright (C) 2007, 2009, 2013 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 <stdbool.h>
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#include <string.h>
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#include <sched.h>
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: env_cmpname
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****************************************************************************/
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static bool env_cmpname(const char *pszname, const char *peqname)
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{
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/* Search until we find anything different in the two names */
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for (; *pszname == *peqname; pszname++, peqname++);
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/* On sucess, pszname will end with '\0' and peqname with '=' */
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if ( *pszname == '\0' && *peqname == '=' )
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{
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return true;
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}
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return false;
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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_findvar
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*
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* Description:
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* Search the provided environment structure for the variable of the
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* specified name.
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*
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* Parameters:
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* group The task group containging environment array to be searched.
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* pname The variable name to find
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*
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* Return Value:
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* A pointer to the name=value string in the environment
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*
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* Assumptions:
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* - Not called from an interrupt handler
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* - Pre-emptions is disabled by caller
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*
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****************************************************************************/
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FAR char *env_findvar(FAR struct task_group_s *group, const char *pname)
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{
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char *ptr;
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char *end;
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/* Verify input parameters */
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DEBUGASSERT(group && pname);
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/* Search for a name=value string with matching name */
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end = &group->tg_envp[group->tg_envsize];
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for (ptr = group->tg_envp;
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ptr < end && !env_cmpname(pname, ptr);
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ptr += (strlen(ptr) + 1));
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/* Check for success */
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return (ptr < end) ? ptr : NULL;
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}
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#endif /* CONFIG_DISABLE_ENVIRON */
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