576 lines
16 KiB
C
576 lines
16 KiB
C
/* $NetBSD: kern_exit.c,v 1.96 2002/08/02 22:45:57 manu Exp $ */
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/*-
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* Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_exit.c 8.10 (Berkeley) 2/23/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.96 2002/08/02 22:45:57 manu Exp $");
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#include "opt_ktrace.h"
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#include "opt_systrace.h"
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#include "opt_sysv.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/map.h>
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#include <sys/ioctl.h>
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#include <sys/proc.h>
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#include <sys/tty.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <sys/kernel.h>
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#include <sys/ktrace.h>
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#include <sys/proc.h>
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#include <sys/buf.h>
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#include <sys/wait.h>
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#include <sys/file.h>
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#include <sys/vnode.h>
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#include <sys/syslog.h>
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#include <sys/malloc.h>
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#include <sys/pool.h>
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#include <sys/resourcevar.h>
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#include <sys/ptrace.h>
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#include <sys/acct.h>
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#include <sys/filedesc.h>
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#include <sys/signalvar.h>
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#include <sys/sched.h>
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#include <sys/mount.h>
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#include <sys/syscallargs.h>
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#include <sys/systrace.h>
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#include <machine/cpu.h>
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#include <uvm/uvm_extern.h>
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/*
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* exit --
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* Death of process.
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*/
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int
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sys_exit(struct proc *p, void *v, register_t *retval)
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{
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struct sys_exit_args /* {
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syscallarg(int) rval;
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} */ *uap = v;
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exit1(p, W_EXITCODE(SCARG(uap, rval), 0));
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/* NOTREACHED */
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return (0);
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}
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/*
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* Exit: deallocate address space and other resources, change proc state
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* to zombie, and unlink proc from allproc and parent's lists. Save exit
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* status and rusage for wait(). Check for child processes and orphan them.
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*/
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void
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exit1(struct proc *p, int rv)
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{
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struct proc *q, *nq;
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int s;
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if (__predict_false(p == initproc))
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panic("init died (signal %d, exit %d)",
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WTERMSIG(rv), WEXITSTATUS(rv));
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#ifdef PGINPROF
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vmsizmon();
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#endif
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if (p->p_flag & P_PROFIL)
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stopprofclock(p);
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p->p_ru = pool_get(&rusage_pool, PR_WAITOK);
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/*
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* If parent is waiting for us to exit or exec, P_PPWAIT is set; we
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* wake up the parent early to avoid deadlock.
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*/
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p->p_flag |= P_WEXIT;
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if (p->p_flag & P_PPWAIT) {
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p->p_flag &= ~P_PPWAIT;
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wakeup((caddr_t)p->p_pptr);
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}
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sigfillset(&p->p_sigctx.ps_sigignore);
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sigemptyset(&p->p_sigctx.ps_siglist);
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p->p_sigctx.ps_sigcheck = 0;
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callout_stop(&p->p_realit_ch);
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/*
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* Close open files and release open-file table.
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* This may block!
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*/
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fdfree(p);
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cwdfree(p);
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doexithooks(p);
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if (SESS_LEADER(p)) {
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struct session *sp = p->p_session;
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if (sp->s_ttyvp) {
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/*
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* Controlling process.
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* Signal foreground pgrp,
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* drain controlling terminal
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* and revoke access to controlling terminal.
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*/
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if (sp->s_ttyp->t_session == sp) {
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if (sp->s_ttyp->t_pgrp)
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pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
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(void) ttywait(sp->s_ttyp);
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/*
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* The tty could have been revoked
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* if we blocked.
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*/
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if (sp->s_ttyvp)
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VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
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}
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if (sp->s_ttyvp)
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vrele(sp->s_ttyvp);
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sp->s_ttyvp = NULL;
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/*
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* s_ttyp is not zero'd; we use this to indicate
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* that the session once had a controlling terminal.
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* (for logging and informational purposes)
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*/
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}
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sp->s_leader = NULL;
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}
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fixjobc(p, p->p_pgrp, 0);
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(void)acct_process(p);
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#ifdef KTRACE
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/*
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* release trace file
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*/
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ktrderef(p);
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#endif
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#ifdef SYSTRACE
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systrace_sys_exit(p);
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#endif
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/*
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* NOTE: WE ARE NO LONGER ALLOWED TO SLEEP!
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*/
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p->p_stat = SDEAD;
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/*
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* Remove proc from pidhash chain so looking it up won't
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* work. Move it from allproc to zombproc, but do not yet
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* wake up the reaper. We will put the proc on the
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* deadproc list later (using the p_hash member), and
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* wake up the reaper when we do.
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*/
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s = proclist_lock_write();
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LIST_REMOVE(p, p_hash);
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LIST_REMOVE(p, p_list);
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LIST_INSERT_HEAD(&zombproc, p, p_list);
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proclist_unlock_write(s);
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/*
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* Give orphaned children to init(8).
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*/
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q = p->p_children.lh_first;
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if (q) /* only need this if any child is S_ZOMB */
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wakeup((caddr_t)initproc);
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for (; q != 0; q = nq) {
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nq = q->p_sibling.le_next;
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proc_reparent(q, initproc);
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/*
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* Traced processes are killed
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* since their existence means someone is screwing up.
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*/
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if (q->p_flag & P_TRACED) {
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q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE);
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psignal(q, SIGKILL);
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}
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}
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/*
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* Reset p_opptr pointer of all former children which got
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* traced by another process and were reparented. We reset
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* it to NULL here; the trace detach code then reparents
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* the child to initproc. We only check allproc list, since
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* eventual former children on zombproc list won't reference
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* p_opptr anymore.
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*/
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if (p->p_flag & P_CHTRACED) {
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struct proc *t;
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proclist_lock_read();
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LIST_FOREACH(t, &allproc, p_list) {
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if (t->p_opptr == p)
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t->p_opptr = NULL;
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}
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proclist_unlock_read();
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}
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/*
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* Save exit status and final rusage info, adding in child rusage
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* info and self times.
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*/
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p->p_xstat = rv;
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*p->p_ru = p->p_stats->p_ru;
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calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
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ruadd(p->p_ru, &p->p_stats->p_cru);
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/*
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* Notify parent that we're gone. If parent has the P_NOCLDWAIT
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* flag set, notify init instead (and hope it will handle
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* this situation).
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*/
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if (p->p_pptr->p_flag & P_NOCLDWAIT) {
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struct proc *pp = p->p_pptr;
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proc_reparent(p, initproc);
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/*
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* If this was the last child of our parent, notify
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* parent, so in case he was wait(2)ing, he will
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* continue.
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*/
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if (pp->p_children.lh_first == NULL)
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wakeup((caddr_t)pp);
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}
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/*
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* Release the process's signal state.
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*/
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sigactsfree(p);
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/*
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* If emulation has process exit hook, call it now.
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*/
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if (p->p_emul->e_proc_exit)
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(*p->p_emul->e_proc_exit)(p);
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/*
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* Clear curproc after we've done all operations
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* that could block, and before tearing down the rest
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* of the process state that might be used from clock, etc.
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* Also, can't clear curproc while we're still runnable,
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* as we're not on a run queue (we are current, just not
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* a proper proc any longer!).
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*
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* Other substructures are freed from wait().
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*/
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curproc = NULL;
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limfree(p->p_limit);
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p->p_limit = NULL;
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/* This process no longer needs to hold the kernel lock. */
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KERNEL_PROC_UNLOCK(p);
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/*
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* Finally, call machine-dependent code to switch to a new
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* context (possibly the idle context). Once we are no longer
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* using the dead process's vmspace and stack, exit2() will be
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* called to schedule those resources to be released by the
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* reaper thread.
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*
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* Note that cpu_exit() will end with a call equivalent to
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* cpu_switch(), finishing our execution (pun intended).
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*/
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cpu_exit(p);
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}
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/*
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* We are called from cpu_exit() once it is safe to schedule the
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* dead process's resources to be freed (i.e., once we've switched to
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* the idle PCB for the current CPU).
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*
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* NOTE: One must be careful with locking in this routine. It's
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* called from a critical section in machine-dependent code, so
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* we should refrain from changing any interrupt state.
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*
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* We lock the deadproc list (a spin lock), place the proc on that
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* list (using the p_hash member), and wake up the reaper.
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*/
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void
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exit2(struct proc *p)
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{
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simple_lock(&deadproc_slock);
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LIST_INSERT_HEAD(&deadproc, p, p_hash);
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simple_unlock(&deadproc_slock);
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wakeup(&deadproc);
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}
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/*
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* Process reaper. This is run by a kernel thread to free the resources
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* of a dead process. Once the resources are free, the process becomes
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* a zombie, and the parent is allowed to read the undead's status.
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*/
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void
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reaper(void *arg)
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{
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struct proc *p;
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KERNEL_PROC_UNLOCK(curproc);
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for (;;) {
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simple_lock(&deadproc_slock);
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p = LIST_FIRST(&deadproc);
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if (p == NULL) {
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/* No work for us; go to sleep until someone exits. */
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(void) ltsleep(&deadproc, PVM|PNORELOCK,
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"reaper", 0, &deadproc_slock);
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continue;
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}
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/* Remove us from the deadproc list. */
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LIST_REMOVE(p, p_hash);
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simple_unlock(&deadproc_slock);
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KERNEL_PROC_LOCK(curproc);
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/*
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* Give machine-dependent code a chance to free any
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* resources it couldn't free while still running on
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* that process's context. This must be done before
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* uvm_exit(), in case these resources are in the PCB.
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*/
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cpu_wait(p);
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/*
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* Free the VM resources we're still holding on to.
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* We must do this from a valid thread because doing
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* so may block.
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*/
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uvm_exit(p);
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/* Process is now a true zombie. */
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p->p_stat = SZOMB;
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/* Wake up the parent so it can get exit status. */
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if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0)
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psignal(p->p_pptr, P_EXITSIG(p));
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KERNEL_PROC_UNLOCK(curproc);
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wakeup((caddr_t)p->p_pptr);
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}
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}
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int
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sys_wait4(struct proc *q, void *v, register_t *retval)
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{
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struct sys_wait4_args /* {
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syscallarg(int) pid;
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syscallarg(int *) status;
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syscallarg(int) options;
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syscallarg(struct rusage *) rusage;
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} */ *uap = v;
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struct proc *p, *t;
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int nfound, status, error, s;
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if (SCARG(uap, pid) == 0)
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SCARG(uap, pid) = -q->p_pgid;
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if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG))
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return (EINVAL);
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loop:
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nfound = 0;
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for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) {
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if (SCARG(uap, pid) != WAIT_ANY &&
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p->p_pid != SCARG(uap, pid) &&
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p->p_pgid != -SCARG(uap, pid))
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continue;
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/*
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* Wait for processes with p_exitsig != SIGCHLD processes only
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* if WALTSIG is set; wait for processes with p_exitsig ==
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* SIGCHLD only if WALTSIG is clear.
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*/
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if (((SCARG(uap, options) & WALLSIG) == 0) &&
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((SCARG(uap, options) & WALTSIG) ?
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(p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)))
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continue;
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nfound++;
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if (p->p_stat == SZOMB) {
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retval[0] = p->p_pid;
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if (SCARG(uap, status)) {
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status = p->p_xstat; /* convert to int */
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error = copyout((caddr_t)&status,
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(caddr_t)SCARG(uap, status),
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sizeof(status));
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if (error)
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return (error);
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}
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if (SCARG(uap, rusage) &&
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(error = copyout((caddr_t)p->p_ru,
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(caddr_t)SCARG(uap, rusage),
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sizeof(struct rusage))))
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return (error);
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/*
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* If we got the child via ptrace(2) or procfs, and
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* the parent is different (meaning the process was
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* attached, rather than run as a child), then we need
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* to give it back to the old parent, and send the
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* parent the exit signal. The rest of the cleanup
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* will be done when the old parent waits on the child.
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*/
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if ((p->p_flag & P_TRACED) && p->p_opptr != p->p_pptr){
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t = p->p_opptr;
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proc_reparent(p, t ? t : initproc);
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p->p_opptr = NULL;
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p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE);
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if (p->p_exitsig != 0)
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psignal(p->p_pptr, P_EXITSIG(p));
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wakeup((caddr_t)p->p_pptr);
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return (0);
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}
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scheduler_wait_hook(q, p);
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p->p_xstat = 0;
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ruadd(&q->p_stats->p_cru, p->p_ru);
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|
pool_put(&rusage_pool, p->p_ru);
|
|
|
|
/*
|
|
* Finally finished with old proc entry.
|
|
* Unlink it from its process group and free it.
|
|
*/
|
|
leavepgrp(p);
|
|
|
|
s = proclist_lock_write();
|
|
LIST_REMOVE(p, p_list); /* off zombproc */
|
|
proclist_unlock_write(s);
|
|
|
|
LIST_REMOVE(p, p_sibling);
|
|
|
|
/*
|
|
* Decrement the count of procs running with this uid.
|
|
*/
|
|
(void)chgproccnt(p->p_cred->p_ruid, -1);
|
|
|
|
/*
|
|
* Free up credentials.
|
|
*/
|
|
if (--p->p_cred->p_refcnt == 0) {
|
|
crfree(p->p_cred->pc_ucred);
|
|
pool_put(&pcred_pool, p->p_cred);
|
|
}
|
|
|
|
/*
|
|
* Release reference to text vnode
|
|
*/
|
|
if (p->p_textvp)
|
|
vrele(p->p_textvp);
|
|
|
|
pool_put(&proc_pool, p);
|
|
nprocs--;
|
|
return (0);
|
|
}
|
|
if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
|
|
(p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) {
|
|
p->p_flag |= P_WAITED;
|
|
retval[0] = p->p_pid;
|
|
|
|
if (SCARG(uap, status)) {
|
|
status = W_STOPCODE(p->p_xstat);
|
|
error = copyout((caddr_t)&status,
|
|
(caddr_t)SCARG(uap, status),
|
|
sizeof(status));
|
|
} else
|
|
error = 0;
|
|
return (error);
|
|
}
|
|
}
|
|
if (nfound == 0)
|
|
return (ECHILD);
|
|
if (SCARG(uap, options) & WNOHANG) {
|
|
retval[0] = 0;
|
|
return (0);
|
|
}
|
|
if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0)
|
|
return (error);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* make process 'parent' the new parent of process 'child'.
|
|
*/
|
|
void
|
|
proc_reparent(struct proc *child, struct proc *parent)
|
|
{
|
|
|
|
if (child->p_pptr == parent)
|
|
return;
|
|
|
|
if (parent == initproc)
|
|
child->p_exitsig = SIGCHLD;
|
|
|
|
LIST_REMOVE(child, p_sibling);
|
|
LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
|
|
child->p_pptr = parent;
|
|
}
|