134 lines
4.0 KiB
C
134 lines
4.0 KiB
C
/****************************************************************************
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* env_getenv.c
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*
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* Copyright (C) 2007, 2008, 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 <sched.h>
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#include <string.h>
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#include <stdlib.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: getenv
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*
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* Description:
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* The getenv() function searches the environment list for a string that
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* matches the string pointed to by name.
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*
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* Parameters:
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* name - The name of the variable to find.
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*
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* Return Value:
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* The value of the valiable (read-only) or NULL on failure
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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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FAR char *getenv(const char *name)
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{
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FAR struct tcb_s *rtcb;
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FAR struct task_group_s *group;
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FAR char *pvar;
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FAR char *pvalue = NULL;
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int ret = OK;
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/* Verify that a string was passed */
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if (!name)
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{
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ret = EINVAL;
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goto errout;
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}
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/* Get a reference to the thread-private environ in the TCB. */
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sched_lock();
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rtcb = (FAR struct tcb_s*)g_readytorun.head;
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group = rtcb->group;
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/* Check if the variable exists */
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if ( !group || (pvar = env_findvar(group, name)) == NULL)
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{
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ret = ENOENT;
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goto errout_with_lock;
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}
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/* It does! Get the value sub-string from the name=value string */
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pvalue = strchr(pvar, '=');
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if (!pvalue)
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{
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/* The name=value string has no '=' This is a bug! */
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ret = EINVAL;
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goto errout_with_lock;
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}
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/* Adjust the pointer so that it points to the value right after the '=' */
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pvalue++;
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sched_unlock();
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return pvalue;
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errout_with_lock:
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sched_unlock();
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errout:
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set_errno(ret);
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return NULL;
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}
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#endif /* CONFIG_DISABLE_ENVIRON */
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