incubator-nuttx/sched/environ/env_removevar.c

105 lines
3.2 KiB
C

/****************************************************************************
* sched/environ/env_removevar.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifndef CONFIG_DISABLE_ENVIRON
#include <string.h>
#include <sched.h>
#include <assert.h>
#include <nuttx/kmalloc.h>
#include "environ/environ.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: env_removevar
*
* Description:
* Remove the referenced name=value pair from the environment
*
* Input Parameters:
* group - The task group with the environment containing the name=value
* pair
* index - A index to the name=value pair in the restroom
*
* Returned Value:
* None
*
* Assumptions:
* - Not called from an interrupt handler
* - Caller has pre-emption disabled
* - Caller will reallocate the environment structure to the correct size
*
****************************************************************************/
void env_removevar(FAR struct task_group_s *group, ssize_t index)
{
DEBUGASSERT(group != NULL && index >= 0 && index < group->tg_envc);
/* Free the allocate environment string */
group_free(group, group->tg_envp[index]);
/* Exchange the last env and the index env */
group->tg_envc--;
if (index == group->tg_envc)
{
group->tg_envp[index] = NULL;
}
else
{
group->tg_envp[index] = group->tg_envp[group->tg_envc];
group->tg_envp[group->tg_envc] = NULL;
}
/* Free the old environment (if there was one) */
if (group->tg_envc == 0)
{
group_free(group, group->tg_envp);
group->tg_envp = NULL;
group->tg_envpc = 0;
}
else if (group->tg_envc <=
(group->tg_envpc - SCHED_ENVIRON_RESERVED * 2))
{
/* Reallocate the environment to reclaim a little memory */
group->tg_envpc = group->tg_envc + SCHED_ENVIRON_RESERVED + 1;
group->tg_envp = group_realloc(group, group->tg_envp,
sizeof(*group->tg_envp) * group->tg_envpc);
DEBUGASSERT(group->tg_envp != NULL);
}
}
#endif /* CONFIG_DISABLE_ENVIRON */