/****************************************************************************
* env_findvar.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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 <string.h>
#include <sched.h>
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: env_cmpname
****************************************************************************/
static boolean env_cmpname(const char *pszname, const char *peqname)
{
/* Search until we find anything different in the two names */
for (; *pszname == *peqname; pszname++, peqname++);
/* On sucess, pszname will end with '\0' and peqname with '=' */
if ( *pszname == '\0' && *peqname == '=' )
{
return TRUE;
}
return FALSE;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: env_findvar
*
* Description:
* Search the provided environment structure for the variable of the
* specified name.
*
* Parameters:
* envp The environment structre to be searched.
* pname The variable name to find
*
* Return Value:
* A pointer to the name=value string in the environment
*
* Assumptions:
* - Not called from an interrupt handler
* - Pre-emptions is disabled by caller
*
****************************************************************************/
FAR char *env_findvar(environ_t *envp, const char *pname)
{
char *ret = NULL;
/* Verify input parameters */
if (envp && pname)
{
char *ptr;
char *end = &envp->ev_env[envp->ev_alloc];
/* Search for a name=value string with matching name */
for (ptr = envp->ev_env; ptr < end && !env_cmpname( pname, ptr); ptr += (strlen(ptr) + 1));
/* Check for success */
if (ptr < end)
{
ret = ptr;
}
}
return ret;
}
#endif /* CONFIG_DISABLE_ENVIRON */
