incubator-nuttx/sched/environ/env_dup.c

153 lines
4.5 KiB
C

/****************************************************************************
* sched/environ/env_dup.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <sys/types.h>
#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: env_dup
*
* Description:
* Copy the internal environment structure of a task. This is the action
* that is performed when a new task is created: The new task has a
* private, exact duplicate of the parent task's environment.
*
* Input Parameters:
* group - The child task group to receive the newly allocated copy of
* the parent task groups environment structure.
* envcp - Pointer to the environment strings to copy.
* Returned Value:
* zero on success
*
* Assumptions:
* Not called from an interrupt handler.
*
****************************************************************************/
int env_dup(FAR struct task_group_s *group, FAR char * const *envcp)
{
FAR char **envp = NULL;
irqstate_t flags;
size_t envc = 0;
size_t size;
int ret = OK;
DEBUGASSERT(group != NULL);
/* Is there an environment ? */
if (envcp != NULL && group->tg_envp == NULL)
{
/* Pre-emption must be disabled throughout the following because the
* environment may be shared.
*/
flags = enter_critical_section();
/* Count the strings */
while (envcp[envc] != NULL)
{
envc++;
}
group->tg_envc = envc;
group->tg_envpc = (envc + SCHED_ENVIRON_RESERVED + 1);
/* A special case is that the parent has an "empty" environment
* allocation, i.e., there is an allocation in place but it
* contains no variable definitions and, hence, envc == 0.
*/
if (envc > 0)
{
/* There is an environment, duplicate it */
envp = group_malloc(group, sizeof(*envp) * group->tg_envpc);
if (envp == NULL)
{
/* The parent's environment can not be inherited due to a
* failure in the allocation of the child environment.
*/
ret = -ENOMEM;
}
else
{
envp[envc] = NULL;
/* Duplicate the parent environment. */
while (envc-- > 0)
{
size = strlen(envcp[envc]) + 1;
envp[envc] = group_malloc(group, size);
if (envp[envc] == NULL)
{
while (envp[++envc] != NULL)
{
group_free(group, envp[envc]);
}
group_free(group, envp);
envp = NULL;
ret = -ENOMEM;
break;
}
strlcpy(envp[envc], envcp[envc], size);
}
}
}
/* Save the child environment allocation. */
group->tg_envp = envp;
leave_critical_section(flags);
}
return ret;
}
#endif /* CONFIG_DISABLE_ENVIRON */