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Alan Carvalho de AssisandXiang Xiao
3cbf6f2168
wait4() is BSD/Linux-standard (used by toybox's "time" applet) but NuttX only had waitpid()+getrusage() separately. Add it to libs/libc/unistd/ built on top of those two existing primitives, so it needs no syscall plumbing of its own and works unmodified across flat/protected/kernel build separation. Prototype added to include/sys/wait.h. Signed-off-by: Alan C. Assis <acassis@gmail.com> Assisted-by: Claude Sonnet 5 <noreply@anthropic.com>
65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
/****************************************************************************
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* libs/libc/unistd/lib_wait4.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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 <sys/wait.h>
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#include <sys/resource.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: wait4
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*
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* Description:
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* wait4() is waitpid() plus the reaped child's resource usage in one
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* call. Built entirely on top of the existing waitpid()/getrusage()
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* primitives (each already correctly proxied across build separation --
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* waitpid() is a real syscall, getrusage() is plain libc), so this needs
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* no syscall plumbing of its own and works unmodified in flat,
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* protected, and kernel builds alike.
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*
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* NuttX's getrusage() only supports RUSAGE_SELF/RUSAGE_CHILDREN (not a
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* specific pid), so the returned usage is exact only when the caller has
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* a single outstanding child at a time.
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*
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****************************************************************************/
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pid_t wait4(pid_t pid, FAR int *stat_loc, int options,
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FAR struct rusage *rusage)
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{
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pid_t ret = waitpid(pid, stat_loc, options);
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if (ret > 0 && rusage != NULL)
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{
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getrusage(RUSAGE_CHILDREN, rusage);
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}
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return ret;
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}
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