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/****************************************************************************
* env_getenv.c
*
* Copyright (C) 2007, 2008, 2013 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 <string.h>
#include <stdlib.h>
#include <errno.h>
#include "os_internal.h"
#include "env_internal.h"
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: getenv
*
* Description:
* The getenv() function searches the environment list for a string that
* matches the string pointed to by name.
*
* Parameters:
* name - The name of the variable to find.
*
* Return Value:
* The value of the valiable (read-only) or NULL on failure
*
* Assumptions:
* Not called from an interrupt handler
*
****************************************************************************/
FAR char *getenv(const char *name)
{
FAR struct tcb_s *rtcb;
FAR struct task_group_s *group;
FAR char *pvar;
FAR char *pvalue = NULL;
int ret = OK;
/* Verify that a string was passed */
if (!name)
{
ret = EINVAL;
goto errout;
}
/* Get a reference to the thread-private environ in the TCB.*/
sched_lock();
rtcb = (FAR struct tcb_s*)g_readytorun.head;
group = rtcb->group;
/* Check if the variable exists */
if ( !group || (pvar = env_findvar(group, name)) == NULL)
{
ret = ENOENT;
goto errout_with_lock;
}
/* It does! Get the value sub-string from the name=value string */
pvalue = strchr(pvar, '=');
if (!pvalue)
{
/* The name=value string has no '=' This is a bug! */
ret = EINVAL;
goto errout_with_lock;
}
/* Adjust the pointer so that it points to the value right after the '=' */
pvalue++;
sched_unlock();
return pvalue;
errout_with_lock:
sched_unlock();
errout:
set_errno(ret);
return NULL;
}
#endif /* CONFIG_DISABLE_ENVIRON */
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