incubator-nuttx/sched/environ/env_unsetenv.c

121 lines
3.3 KiB
C

/****************************************************************************
* sched/environ/env_unsetenv.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 <sched.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/kmalloc.h>
#include "sched/sched.h"
#include "environ/environ.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: unsetenv
*
* Description:
* The unsetenv() function deletes the variable name from the environment.
*
* Input Parameters:
* name - The name of the variable to delete
*
* Returned Value:
* Zero on success
*
* Assumptions:
* Not called from an interrupt handler
*
****************************************************************************/
int unsetenv(FAR const char *name)
{
FAR struct tcb_s *rtcb = this_task();
FAR struct task_group_s *group = rtcb->group;
FAR char *pvar;
FAR char *newenvp;
int newsize;
int ret = OK;
DEBUGASSERT(name && group);
/* Check if the variable exists */
sched_lock();
if (group && (pvar = env_findvar(group, name)) != NULL)
{
/* It does! Remove the name=value pair from the environment. */
env_removevar(group, pvar);
/* Reallocate the new environment buffer */
newsize = group->tg_envsize;
if (newsize <= 0)
{
/* Free the old environment (if there was one) */
if (group->tg_envp != NULL)
{
kumm_free(group->tg_envp);
group->tg_envp = NULL;
}
group->tg_envsize = 0;
}
else
{
/* Reallocate the environment to reclaim a little memory */
newenvp = (FAR char *)kumm_realloc(group->tg_envp, newsize);
if (newenvp == NULL)
{
set_errno(ENOMEM);
ret = ERROR;
}
else
{
/* Save the new environment pointer (it might have changed due
* to reallocation).
*/
group->tg_envp = newenvp;
}
}
}
sched_unlock();
return ret;
}
#endif /* CONFIG_DISABLE_ENVIRON */