* libs/libc/unistd/lib_fork.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>
#include <nuttx/arch.h>
#include <nuttx/mutex.h>
#include <nuttx/tls_task.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/wait.h>
#include <errno.h>
#include <debug.h>
#if defined(CONFIG_ARCH_HAVE_FORK)
* Private Functions
****************************************************************************/
#ifdef CONFIG_PTHREAD_ATFORK
* Name: atfork_prepare
*
* Description:
* Invoke this method in the parent process before fork starts
*
****************************************************************************/
static void atfork_prepare(void)
{
FAR struct task_info_s *info = task_get_info();
FAR struct list_node *list = &info->ta_atfork;
FAR struct pthread_atfork_s *entry;
* order of registration
* so we iterate over the func list in reverse order
*/
nxrmutex_lock(&info->ta_lock);
list_for_every_entry_reverse(list, entry,
struct pthread_atfork_s, node)
{
if (entry->prepare != NULL)
{
entry->prepare();
}
}
nxrmutex_unlock(&info->ta_lock);
}
* Name: atfork_child
*
* Description:
* Invoke this method in the child process after fork completes
*
****************************************************************************/
static void atfork_child(void)
{
FAR struct task_info_s *info = task_get_info();
FAR struct list_node *list = &info->ta_atfork;
FAR struct pthread_atfork_s *entry;
nxrmutex_lock(&info->ta_lock);
list_for_every_entry(list, entry,
struct pthread_atfork_s, node)
{
if (entry->child != NULL)
{
entry->child();
}
}
nxrmutex_unlock(&info->ta_lock);
}
* Name: atfork_parent
*
* Description:
* Invoke this method in the parent process after fork completes
*
****************************************************************************/
static void atfork_parent(void)
{
FAR struct task_info_s *info = task_get_info();
FAR struct list_node *list = &info->ta_atfork;
FAR struct pthread_atfork_s *entry;
nxrmutex_lock(&info->ta_lock);
list_for_every_entry(list, entry,
struct pthread_atfork_s, node)
{
if (entry->parent != NULL)
{
entry->parent();
}
}
nxrmutex_unlock(&info->ta_lock);
}
#endif
* Public Functions
****************************************************************************/
* Name: fork
*
* Description:
* The fork() function is a wrapper of up_fork() syscall
*
* Returned Value:
* Upon successful completion, fork() returns 0 to the child process and
* returns the process ID of the child process to the parent process.
* Otherwise, -1 is returned to the parent, no child process is created,
* and errno is set to indicate the error.
*
****************************************************************************/
pid_t fork(void)
{
pid_t pid;
#ifdef CONFIG_PTHREAD_ATFORK
atfork_prepare();
#endif
pid = up_fork();
#ifdef CONFIG_PTHREAD_ATFORK
if (pid == 0)
{
atfork_child();
}
else
{
atfork_parent();
}
#endif
return pid;
}
#if defined(CONFIG_SCHED_WAITPID)
* Public Functions
****************************************************************************/
* Name: vfork
*
* Description:
* The vfork() function is implemented based on fork() function, on
* vfork(), the parent task need to wait until the child task is performing
* exec or running finished.
*
* Returned Value:
* Upon successful completion, vfork() returns 0 to the child process and
* returns the process ID of the child process to the parent process.
* Otherwise, -1 is returned to the parent, no child process is created,
* and errno is set to indicate the error.
*
****************************************************************************/
pid_t vfork(void)
{
int status = 0;
int ret;
pid_t pid;
#ifdef CONFIG_PTHREAD_ATFORK
atfork_prepare();
#endif
pid = up_fork();
#ifdef CONFIG_PTHREAD_ATFORK
if (pid == 0)
{
atfork_child();
}
else
{
atfork_parent();
}
#endif
if (pid != 0)
{
* until running finished or performing exec
*/
ret = waitpid(pid, &status, WNOWAIT);
if (ret < 0)
{
serr("ERROR: waitpid failed: %d\n", get_errno());
}
}
return pid;
}
#endif
#endif