77 lines
2.6 KiB
C
77 lines
2.6 KiB
C
/****************************************************************************
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* libs/libc/unistd/lib_vfork.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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#include <unistd.h>
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#include <sys/wait.h>
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#include <errno.h>
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#include <debug.h>
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#if defined(CONFIG_ARCH_HAVE_FORK) && defined(CONFIG_SCHED_WAITPID)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: vfork
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*
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* Description:
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* The vfork() function is implemented based on fork() function, on
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* vfork(), the parent task need to wait until the child task is performing
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* exec or running finished.
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*
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* Returned Value:
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* Upon successful completion, vfork() returns 0 to the child process and
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* returns the process ID of the child process to the parent process.
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* Otherwise, -1 is returned to the parent, no child process is created,
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* and errno is set to indicate the error.
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*
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****************************************************************************/
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pid_t vfork(void)
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{
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int status = 0;
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int ret;
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pid_t pid = fork();
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if (pid != 0)
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{
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/* we are in parent task, and we need to wait the child task
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* until running finished or performing exec
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*/
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ret = waitpid(pid, &status, WNOWAIT);
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if (ret < 0)
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{
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serr("ERROR: waitpid failed: %d\n", get_errno());
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}
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}
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return pid;
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}
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#endif /* CONFIG_ARCH_HAVE_FORK && CONFIG_SCHED_WAITPID */
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