c33d1c9c97
1. as we can use fork to implement vfork, so we rename the vfork to fork, and use the fork method as the base to implement vfork method 2. create the vfork function as a libc function based on fork function Signed-off-by: guoshichao <guoshichao@xiaomi.com>
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, 0);
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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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