112 lines
3.0 KiB
C
112 lines
3.0 KiB
C
/****************************************************************************
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* sched/environ/env_getenv.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 "sched/sched.h"
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#include "environ/environ.h"
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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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* Input Parameters:
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* name - The name of the variable to find.
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*
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* Returned Value:
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* The value of the variable (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(FAR 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 *pvalue = NULL;
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ssize_t ret = OK;
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/* Verify that a string was passed */
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if (name == NULL)
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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 = this_task();
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group = rtcb->group;
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/* Check if the variable exists */
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if (group == NULL || (ret = env_findvar(group, name)) < 0)
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{
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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(group->tg_envp[ret], '=');
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if (pvalue == NULL)
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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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