e8efa7328e
I'm not convinced there is anything major wrong with the patch but them's the rules.. I am using my "David's mentor" hat to revert this as he's offline for a while.
913 lines
23 KiB
C
913 lines
23 KiB
C
/*
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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_fork.c 8.6 (Berkeley) 4/8/94
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* $FreeBSD$
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*/
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#include "opt_ktrace.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/filedesc.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/pioctl.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/syscall.h>
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#include <sys/vnode.h>
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#include <sys/acct.h>
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#include <sys/mac.h>
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#include <sys/ktr.h>
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#include <sys/ktrace.h>
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#include <sys/kthread.h>
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#include <sys/unistd.h>
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#include <sys/jail.h>
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#include <sys/sx.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_extern.h>
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#include <vm/uma.h>
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#include <sys/vmmeter.h>
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#include <sys/user.h>
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#include <machine/critical.h>
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static MALLOC_DEFINE(M_ATFORK, "atfork", "atfork callback");
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/*
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* These are the stuctures used to create a callout list for things to do
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* when forking a process
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*/
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struct forklist {
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forklist_fn function;
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TAILQ_ENTRY(forklist) next;
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};
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static struct sx fork_list_lock;
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TAILQ_HEAD(forklist_head, forklist);
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static struct forklist_head fork_list = TAILQ_HEAD_INITIALIZER(fork_list);
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#ifndef _SYS_SYSPROTO_H_
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struct fork_args {
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int dummy;
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};
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#endif
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int forksleep; /* Place for fork1() to sleep on. */
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static void
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init_fork_list(void *data __unused)
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{
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sx_init(&fork_list_lock, "fork list");
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}
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SYSINIT(fork_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_fork_list, NULL);
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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fork(td, uap)
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struct thread *td;
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struct fork_args *uap;
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{
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int error;
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struct proc *p2;
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mtx_lock(&Giant);
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error = fork1(td, RFFDG | RFPROC, 0, &p2);
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if (error == 0) {
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td->td_retval[0] = p2->p_pid;
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td->td_retval[1] = 0;
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}
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mtx_unlock(&Giant);
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return error;
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}
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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vfork(td, uap)
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struct thread *td;
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struct vfork_args *uap;
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{
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int error;
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struct proc *p2;
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mtx_lock(&Giant);
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error = fork1(td, RFFDG | RFPROC | RFPPWAIT | RFMEM, 0, &p2);
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if (error == 0) {
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td->td_retval[0] = p2->p_pid;
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td->td_retval[1] = 0;
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}
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mtx_unlock(&Giant);
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return error;
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}
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/*
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* MPSAFE
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*/
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int
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rfork(td, uap)
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struct thread *td;
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struct rfork_args *uap;
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{
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int error;
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struct proc *p2;
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/* Don't allow kernel only flags. */
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if ((uap->flags & RFKERNELONLY) != 0)
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return (EINVAL);
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mtx_lock(&Giant);
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error = fork1(td, uap->flags, 0, &p2);
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if (error == 0) {
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td->td_retval[0] = p2 ? p2->p_pid : 0;
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td->td_retval[1] = 0;
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}
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mtx_unlock(&Giant);
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return error;
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}
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|
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int nprocs = 1; /* process 0 */
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int lastpid = 0;
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SYSCTL_INT(_kern, OID_AUTO, lastpid, CTLFLAG_RD, &lastpid, 0,
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"Last used PID");
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/*
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* Random component to lastpid generation. We mix in a random factor to make
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* it a little harder to predict. We sanity check the modulus value to avoid
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* doing it in critical paths. Don't let it be too small or we pointlessly
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* waste randomness entropy, and don't let it be impossibly large. Using a
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* modulus that is too big causes a LOT more process table scans and slows
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* down fork processing as the pidchecked caching is defeated.
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*/
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static int randompid = 0;
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static int
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sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
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{
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int error, pid;
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sysctl_wire_old_buffer(req, sizeof(int));
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sx_xlock(&allproc_lock);
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pid = randompid;
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error = sysctl_handle_int(oidp, &pid, 0, req);
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if (error == 0 && req->newptr != NULL) {
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if (pid < 0 || pid > PID_MAX - 100) /* out of range */
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pid = PID_MAX - 100;
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else if (pid < 2) /* NOP */
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pid = 0;
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else if (pid < 100) /* Make it reasonable */
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pid = 100;
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randompid = pid;
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}
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sx_xunlock(&allproc_lock);
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return (error);
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}
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SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
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0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
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int
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fork1(td, flags, pages, procp)
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struct thread *td; /* parent proc */
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int flags;
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int pages;
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struct proc **procp; /* child proc */
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{
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struct proc *p2, *pptr;
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uid_t uid;
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struct proc *newproc;
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int trypid;
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int ok;
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static int pidchecked = 0;
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struct forklist *ep;
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struct filedesc *fd;
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struct proc *p1 = td->td_proc;
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struct thread *td2;
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struct kse *ke2;
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struct ksegrp *kg2;
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struct sigacts *newsigacts;
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struct procsig *newprocsig;
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int error;
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GIANT_REQUIRED;
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/* Can't copy and clear */
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if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
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return (EINVAL);
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/*
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* Here we don't create a new process, but we divorce
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* certain parts of a process from itself.
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*/
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if ((flags & RFPROC) == 0) {
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vm_forkproc(td, NULL, NULL, flags);
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/*
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* Close all file descriptors.
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*/
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if (flags & RFCFDG) {
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struct filedesc *fdtmp;
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fdtmp = fdinit(td->td_proc->p_fd);
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fdfree(td);
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p1->p_fd = fdtmp;
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}
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/*
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* Unshare file descriptors (from parent.)
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*/
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if (flags & RFFDG) {
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FILEDESC_LOCK(p1->p_fd);
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if (p1->p_fd->fd_refcnt > 1) {
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struct filedesc *newfd;
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newfd = fdcopy(td->td_proc->p_fd);
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FILEDESC_UNLOCK(p1->p_fd);
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fdfree(td);
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p1->p_fd = newfd;
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} else
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FILEDESC_UNLOCK(p1->p_fd);
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}
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*procp = NULL;
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return (0);
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}
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if (p1->p_flag & P_KSES) {
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/*
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* Idle the other threads for a second.
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* Since the user space is copied, it must remain stable.
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* In addition, all threads (from the user perspective)
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* need to either be suspended or in the kernel,
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* where they will try restart in the parent and will
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* be aborted in the child.
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*/
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PROC_LOCK(p1);
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if (thread_single(SINGLE_NO_EXIT)) {
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/* Abort.. someone else is single threading before us */
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PROC_UNLOCK(p1);
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return (ERESTART);
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}
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PROC_UNLOCK(p1);
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/*
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* All other activity in this process
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* is now suspended at the user boundary,
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* (or other safe places if we think of any).
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*/
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}
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|
/* Allocate new proc. */
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newproc = uma_zalloc(proc_zone, 0);
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#ifdef MAC
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mac_init_proc(newproc);
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#endif
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|
/*
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* Although process entries are dynamically created, we still keep
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* a global limit on the maximum number we will create. Don't allow
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* a nonprivileged user to use the last ten processes; don't let root
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* exceed the limit. The variable nprocs is the current number of
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* processes, maxproc is the limit.
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*/
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sx_xlock(&allproc_lock);
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uid = td->td_ucred->cr_ruid;
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if ((nprocs >= maxproc - 10 && uid != 0) || nprocs >= maxproc) {
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error = EAGAIN;
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goto fail;
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}
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|
|
|
/*
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|
* Increment the count of procs running with this uid. Don't allow
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* a nonprivileged user to exceed their current limit.
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|
*/
|
|
PROC_LOCK(p1);
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|
ok = chgproccnt(td->td_ucred->cr_ruidinfo, 1,
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(uid != 0) ? p1->p_rlimit[RLIMIT_NPROC].rlim_cur : 0);
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PROC_UNLOCK(p1);
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if (!ok) {
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error = EAGAIN;
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goto fail;
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}
|
|
|
|
/*
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|
* Increment the nprocs resource before blocking can occur. There
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* are hard-limits as to the number of processes that can run.
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*/
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nprocs++;
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|
|
/*
|
|
* Find an unused process ID. We remember a range of unused IDs
|
|
* ready to use (from lastpid+1 through pidchecked-1).
|
|
*
|
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* If RFHIGHPID is set (used during system boot), do not allocate
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* low-numbered pids.
|
|
*/
|
|
trypid = lastpid + 1;
|
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if (flags & RFHIGHPID) {
|
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if (trypid < 10) {
|
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trypid = 10;
|
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}
|
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} else {
|
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if (randompid)
|
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trypid += arc4random() % randompid;
|
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}
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|
retry:
|
|
/*
|
|
* If the process ID prototype has wrapped around,
|
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* restart somewhat above 0, as the low-numbered procs
|
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* tend to include daemons that don't exit.
|
|
*/
|
|
if (trypid >= PID_MAX) {
|
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trypid = trypid % PID_MAX;
|
|
if (trypid < 100)
|
|
trypid += 100;
|
|
pidchecked = 0;
|
|
}
|
|
if (trypid >= pidchecked) {
|
|
int doingzomb = 0;
|
|
|
|
pidchecked = PID_MAX;
|
|
/*
|
|
* Scan the active and zombie procs to check whether this pid
|
|
* is in use. Remember the lowest pid that's greater
|
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* than trypid, so we can avoid checking for a while.
|
|
*/
|
|
p2 = LIST_FIRST(&allproc);
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|
again:
|
|
for (; p2 != NULL; p2 = LIST_NEXT(p2, p_list)) {
|
|
PROC_LOCK(p2);
|
|
while (p2->p_pid == trypid ||
|
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p2->p_pgrp->pg_id == trypid ||
|
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p2->p_session->s_sid == trypid) {
|
|
trypid++;
|
|
if (trypid >= pidchecked) {
|
|
PROC_UNLOCK(p2);
|
|
goto retry;
|
|
}
|
|
}
|
|
if (p2->p_pid > trypid && pidchecked > p2->p_pid)
|
|
pidchecked = p2->p_pid;
|
|
if (p2->p_pgrp->pg_id > trypid &&
|
|
pidchecked > p2->p_pgrp->pg_id)
|
|
pidchecked = p2->p_pgrp->pg_id;
|
|
if (p2->p_session->s_sid > trypid &&
|
|
pidchecked > p2->p_session->s_sid)
|
|
pidchecked = p2->p_session->s_sid;
|
|
PROC_UNLOCK(p2);
|
|
}
|
|
if (!doingzomb) {
|
|
doingzomb = 1;
|
|
p2 = LIST_FIRST(&zombproc);
|
|
goto again;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* RFHIGHPID does not mess with the lastpid counter during boot.
|
|
*/
|
|
if (flags & RFHIGHPID)
|
|
pidchecked = 0;
|
|
else
|
|
lastpid = trypid;
|
|
|
|
p2 = newproc;
|
|
p2->p_state = PRS_NEW; /* protect against others */
|
|
p2->p_pid = trypid;
|
|
LIST_INSERT_HEAD(&allproc, p2, p_list);
|
|
LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
|
|
sx_xunlock(&allproc_lock);
|
|
|
|
/*
|
|
* Malloc things while we don't hold any locks.
|
|
*/
|
|
if (flags & RFSIGSHARE) {
|
|
MALLOC(newsigacts, struct sigacts *,
|
|
sizeof(struct sigacts), M_SUBPROC, 0);
|
|
newprocsig = NULL;
|
|
} else {
|
|
newsigacts = NULL;
|
|
MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
|
|
M_SUBPROC, 0);
|
|
}
|
|
|
|
/*
|
|
* Copy filedesc.
|
|
* XXX: This is busted. fd*() need to not take proc
|
|
* arguments or something.
|
|
*/
|
|
if (flags & RFCFDG)
|
|
fd = fdinit(td->td_proc->p_fd);
|
|
else if (flags & RFFDG) {
|
|
FILEDESC_LOCK(p1->p_fd);
|
|
fd = fdcopy(td->td_proc->p_fd);
|
|
FILEDESC_UNLOCK(p1->p_fd);
|
|
} else
|
|
fd = fdshare(p1->p_fd);
|
|
|
|
/*
|
|
* Make a proc table entry for the new process.
|
|
* Start by zeroing the section of proc that is zero-initialized,
|
|
* then copy the section that is copied directly from the parent.
|
|
*/
|
|
td2 = FIRST_THREAD_IN_PROC(p2);
|
|
kg2 = FIRST_KSEGRP_IN_PROC(p2);
|
|
ke2 = FIRST_KSE_IN_KSEGRP(kg2);
|
|
|
|
/* Allocate and switch to an alternate kstack if specified */
|
|
if (pages != 0)
|
|
pmap_new_altkstack(td2, pages);
|
|
|
|
#define RANGEOF(type, start, end) (offsetof(type, end) - offsetof(type, start))
|
|
|
|
bzero(&p2->p_startzero,
|
|
(unsigned) RANGEOF(struct proc, p_startzero, p_endzero));
|
|
bzero(&ke2->ke_startzero,
|
|
(unsigned) RANGEOF(struct kse, ke_startzero, ke_endzero));
|
|
bzero(&td2->td_startzero,
|
|
(unsigned) RANGEOF(struct thread, td_startzero, td_endzero));
|
|
bzero(&kg2->kg_startzero,
|
|
(unsigned) RANGEOF(struct ksegrp, kg_startzero, kg_endzero));
|
|
|
|
mtx_init(&p2->p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
|
|
PROC_LOCK(p2);
|
|
PROC_LOCK(p1);
|
|
|
|
bcopy(&p1->p_startcopy, &p2->p_startcopy,
|
|
(unsigned) RANGEOF(struct proc, p_startcopy, p_endcopy));
|
|
bcopy(&td->td_startcopy, &td2->td_startcopy,
|
|
(unsigned) RANGEOF(struct thread, td_startcopy, td_endcopy));
|
|
bcopy(&td->td_ksegrp->kg_startcopy, &kg2->kg_startcopy,
|
|
(unsigned) RANGEOF(struct ksegrp, kg_startcopy, kg_endcopy));
|
|
#undef RANGEOF
|
|
|
|
/* Set up the thread as an active thread (as if runnable). */
|
|
ke2->ke_state = KES_THREAD;
|
|
ke2->ke_thread = td2;
|
|
ke2->ke_owner = td2;
|
|
td2->td_kse = ke2;
|
|
td2->td_flags &= ~TDF_UNBOUND; /* For the rest of this syscall. */
|
|
|
|
/*
|
|
* Duplicate sub-structures as needed.
|
|
* Increase reference counts on shared objects.
|
|
* The p_stats and p_sigacts substructs are set in vm_forkproc.
|
|
*/
|
|
p2->p_flag = 0;
|
|
mtx_lock_spin(&sched_lock);
|
|
p2->p_sflag = PS_INMEM;
|
|
if (p1->p_sflag & PS_PROFIL)
|
|
startprofclock(p2);
|
|
/*
|
|
* Allow the scheduler to adjust the priority of the child and
|
|
* parent while we hold the sched_lock.
|
|
*/
|
|
sched_fork(td->td_ksegrp, kg2);
|
|
|
|
mtx_unlock_spin(&sched_lock);
|
|
p2->p_ucred = crhold(td->td_ucred);
|
|
td2->td_ucred = crhold(p2->p_ucred); /* XXXKSE */
|
|
|
|
pargs_hold(p2->p_args);
|
|
|
|
if (flags & RFSIGSHARE) {
|
|
p2->p_procsig = p1->p_procsig;
|
|
p2->p_procsig->ps_refcnt++;
|
|
if (p1->p_sigacts == &p1->p_uarea->u_sigacts) {
|
|
/*
|
|
* Set p_sigacts to the new shared structure.
|
|
* Note that this is updating p1->p_sigacts at the
|
|
* same time, since p_sigacts is just a pointer to
|
|
* the shared p_procsig->ps_sigacts.
|
|
*/
|
|
p2->p_sigacts = newsigacts;
|
|
newsigacts = NULL;
|
|
*p2->p_sigacts = p1->p_uarea->u_sigacts;
|
|
}
|
|
} else {
|
|
p2->p_procsig = newprocsig;
|
|
newprocsig = NULL;
|
|
bcopy(p1->p_procsig, p2->p_procsig, sizeof(*p2->p_procsig));
|
|
p2->p_procsig->ps_refcnt = 1;
|
|
p2->p_sigacts = NULL; /* finished in vm_forkproc() */
|
|
}
|
|
if (flags & RFLINUXTHPN)
|
|
p2->p_sigparent = SIGUSR1;
|
|
else
|
|
p2->p_sigparent = SIGCHLD;
|
|
|
|
/* Bump references to the text vnode (for procfs) */
|
|
p2->p_textvp = p1->p_textvp;
|
|
if (p2->p_textvp)
|
|
VREF(p2->p_textvp);
|
|
p2->p_fd = fd;
|
|
PROC_UNLOCK(p1);
|
|
PROC_UNLOCK(p2);
|
|
|
|
/*
|
|
* If p_limit is still copy-on-write, bump refcnt,
|
|
* otherwise get a copy that won't be modified.
|
|
* (If PL_SHAREMOD is clear, the structure is shared
|
|
* copy-on-write.)
|
|
*/
|
|
if (p1->p_limit->p_lflags & PL_SHAREMOD)
|
|
p2->p_limit = limcopy(p1->p_limit);
|
|
else {
|
|
p2->p_limit = p1->p_limit;
|
|
p2->p_limit->p_refcnt++;
|
|
}
|
|
|
|
/*
|
|
* Setup linkage for kernel based threading
|
|
*/
|
|
if((flags & RFTHREAD) != 0) {
|
|
mtx_lock(&ppeers_lock);
|
|
p2->p_peers = p1->p_peers;
|
|
p1->p_peers = p2;
|
|
p2->p_leader = p1->p_leader;
|
|
mtx_unlock(&ppeers_lock);
|
|
PROC_LOCK(p1->p_leader);
|
|
if ((p1->p_leader->p_flag & P_WEXIT) != 0) {
|
|
PROC_UNLOCK(p1->p_leader);
|
|
/*
|
|
* The task leader is exiting, so process p1 is
|
|
* going to be killed shortly. Since p1 obviously
|
|
* isn't dead yet, we know that the leader is either
|
|
* sending SIGKILL's to all the processes in this
|
|
* task or is sleeping waiting for all the peers to
|
|
* exit. We let p1 complete the fork, but we need
|
|
* to go ahead and kill the new process p2 since
|
|
* the task leader may not get a chance to send
|
|
* SIGKILL to it. We leave it on the list so that
|
|
* the task leader will wait for this new process
|
|
* to commit suicide.
|
|
*/
|
|
PROC_LOCK(p2);
|
|
psignal(p2, SIGKILL);
|
|
PROC_UNLOCK(p2);
|
|
} else
|
|
PROC_UNLOCK(p1->p_leader);
|
|
} else {
|
|
p2->p_peers = NULL;
|
|
p2->p_leader = p2;
|
|
}
|
|
|
|
sx_xlock(&proctree_lock);
|
|
PGRP_LOCK(p1->p_pgrp);
|
|
PROC_LOCK(p2);
|
|
PROC_LOCK(p1);
|
|
|
|
/*
|
|
* Preserve some more flags in subprocess. PS_PROFIL has already
|
|
* been preserved.
|
|
*/
|
|
p2->p_flag |= p1->p_flag & (P_SUGID | P_ALTSTACK);
|
|
SESS_LOCK(p1->p_session);
|
|
if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
|
|
p2->p_flag |= P_CONTROLT;
|
|
SESS_UNLOCK(p1->p_session);
|
|
if (flags & RFPPWAIT)
|
|
p2->p_flag |= P_PPWAIT;
|
|
|
|
LIST_INSERT_AFTER(p1, p2, p_pglist);
|
|
PGRP_UNLOCK(p1->p_pgrp);
|
|
LIST_INIT(&p2->p_children);
|
|
|
|
callout_init(&p2->p_itcallout, 0);
|
|
|
|
#ifdef KTRACE
|
|
/*
|
|
* Copy traceflag and tracefile if enabled.
|
|
*/
|
|
mtx_lock(&ktrace_mtx);
|
|
KASSERT(p2->p_tracep == NULL, ("new process has a ktrace vnode"));
|
|
if (p1->p_traceflag & KTRFAC_INHERIT) {
|
|
p2->p_traceflag = p1->p_traceflag;
|
|
if ((p2->p_tracep = p1->p_tracep) != NULL)
|
|
VREF(p2->p_tracep);
|
|
}
|
|
mtx_unlock(&ktrace_mtx);
|
|
#endif
|
|
|
|
/*
|
|
* If PF_FORK is set, the child process inherits the
|
|
* procfs ioctl flags from its parent.
|
|
*/
|
|
if (p1->p_pfsflags & PF_FORK) {
|
|
p2->p_stops = p1->p_stops;
|
|
p2->p_pfsflags = p1->p_pfsflags;
|
|
}
|
|
|
|
/*
|
|
* This begins the section where we must prevent the parent
|
|
* from being swapped.
|
|
*/
|
|
_PHOLD(p1);
|
|
PROC_UNLOCK(p1);
|
|
|
|
/*
|
|
* Attach the new process to its parent.
|
|
*
|
|
* If RFNOWAIT is set, the newly created process becomes a child
|
|
* of init. This effectively disassociates the child from the
|
|
* parent.
|
|
*/
|
|
if (flags & RFNOWAIT)
|
|
pptr = initproc;
|
|
else
|
|
pptr = p1;
|
|
p2->p_pptr = pptr;
|
|
LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling);
|
|
PROC_UNLOCK(p2);
|
|
sx_xunlock(&proctree_lock);
|
|
|
|
KASSERT(newprocsig == NULL, ("unused newprocsig"));
|
|
if (newsigacts != NULL)
|
|
FREE(newsigacts, M_SUBPROC);
|
|
/*
|
|
* Finish creating the child process. It will return via a different
|
|
* execution path later. (ie: directly into user mode)
|
|
*/
|
|
vm_forkproc(td, p2, td2, flags);
|
|
|
|
if (flags == (RFFDG | RFPROC)) {
|
|
cnt.v_forks++;
|
|
cnt.v_forkpages += p2->p_vmspace->vm_dsize +
|
|
p2->p_vmspace->vm_ssize;
|
|
} else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) {
|
|
cnt.v_vforks++;
|
|
cnt.v_vforkpages += p2->p_vmspace->vm_dsize +
|
|
p2->p_vmspace->vm_ssize;
|
|
} else if (p1 == &proc0) {
|
|
cnt.v_kthreads++;
|
|
cnt.v_kthreadpages += p2->p_vmspace->vm_dsize +
|
|
p2->p_vmspace->vm_ssize;
|
|
} else {
|
|
cnt.v_rforks++;
|
|
cnt.v_rforkpages += p2->p_vmspace->vm_dsize +
|
|
p2->p_vmspace->vm_ssize;
|
|
}
|
|
|
|
/*
|
|
* Both processes are set up, now check if any loadable modules want
|
|
* to adjust anything.
|
|
* What if they have an error? XXX
|
|
*/
|
|
sx_slock(&fork_list_lock);
|
|
TAILQ_FOREACH(ep, &fork_list, next) {
|
|
(*ep->function)(p1, p2, flags);
|
|
}
|
|
sx_sunlock(&fork_list_lock);
|
|
|
|
/*
|
|
* If RFSTOPPED not requested, make child runnable and add to
|
|
* run queue.
|
|
*/
|
|
microtime(&(p2->p_stats->p_start));
|
|
p2->p_acflag = AFORK;
|
|
if ((flags & RFSTOPPED) == 0) {
|
|
mtx_lock_spin(&sched_lock);
|
|
p2->p_state = PRS_NORMAL;
|
|
TD_SET_CAN_RUN(td2);
|
|
setrunqueue(td2);
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Now can be swapped.
|
|
*/
|
|
PROC_LOCK(p1);
|
|
_PRELE(p1);
|
|
|
|
/*
|
|
* tell any interested parties about the new process
|
|
*/
|
|
KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid);
|
|
PROC_UNLOCK(p1);
|
|
|
|
/*
|
|
* Preserve synchronization semantics of vfork. If waiting for
|
|
* child to exec or exit, set P_PPWAIT on child, and sleep on our
|
|
* proc (in case of exit).
|
|
*/
|
|
PROC_LOCK(p2);
|
|
while (p2->p_flag & P_PPWAIT)
|
|
msleep(p1, &p2->p_mtx, PWAIT, "ppwait", 0);
|
|
PROC_UNLOCK(p2);
|
|
|
|
/*
|
|
* If other threads are waiting, let them continue now
|
|
*/
|
|
if (p1->p_flag & P_KSES) {
|
|
PROC_LOCK(p1);
|
|
thread_single_end();
|
|
PROC_UNLOCK(p1);
|
|
}
|
|
|
|
/*
|
|
* Return child proc pointer to parent.
|
|
*/
|
|
*procp = p2;
|
|
return (0);
|
|
fail:
|
|
sx_xunlock(&allproc_lock);
|
|
uma_zfree(proc_zone, newproc);
|
|
if (p1->p_flag & P_KSES) {
|
|
PROC_LOCK(p1);
|
|
thread_single_end();
|
|
PROC_UNLOCK(p1);
|
|
}
|
|
tsleep(&forksleep, PUSER, "fork", hz / 2);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* The next two functionms are general routines to handle adding/deleting
|
|
* items on the fork callout list.
|
|
*
|
|
* at_fork():
|
|
* Take the arguments given and put them onto the fork callout list,
|
|
* However first make sure that it's not already there.
|
|
* Returns 0 on success or a standard error number.
|
|
*/
|
|
|
|
int
|
|
at_fork(function)
|
|
forklist_fn function;
|
|
{
|
|
struct forklist *ep;
|
|
|
|
#ifdef INVARIANTS
|
|
/* let the programmer know if he's been stupid */
|
|
if (rm_at_fork(function))
|
|
printf("WARNING: fork callout entry (%p) already present\n",
|
|
function);
|
|
#endif
|
|
ep = malloc(sizeof(*ep), M_ATFORK, M_NOWAIT);
|
|
if (ep == NULL)
|
|
return (ENOMEM);
|
|
ep->function = function;
|
|
sx_xlock(&fork_list_lock);
|
|
TAILQ_INSERT_TAIL(&fork_list, ep, next);
|
|
sx_xunlock(&fork_list_lock);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Scan the exit callout list for the given item and remove it..
|
|
* Returns the number of items removed (0 or 1)
|
|
*/
|
|
|
|
int
|
|
rm_at_fork(function)
|
|
forklist_fn function;
|
|
{
|
|
struct forklist *ep;
|
|
|
|
sx_xlock(&fork_list_lock);
|
|
TAILQ_FOREACH(ep, &fork_list, next) {
|
|
if (ep->function == function) {
|
|
TAILQ_REMOVE(&fork_list, ep, next);
|
|
sx_xunlock(&fork_list_lock);
|
|
free(ep, M_ATFORK);
|
|
return(1);
|
|
}
|
|
}
|
|
sx_xunlock(&fork_list_lock);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Handle the return of a child process from fork1(). This function
|
|
* is called from the MD fork_trampoline() entry point.
|
|
*/
|
|
void
|
|
fork_exit(callout, arg, frame)
|
|
void (*callout)(void *, struct trapframe *);
|
|
void *arg;
|
|
struct trapframe *frame;
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
if ((td = PCPU_GET(deadthread))) {
|
|
PCPU_SET(deadthread, NULL);
|
|
thread_stash(td);
|
|
}
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
|
|
p->p_state = PRS_NORMAL;
|
|
/*
|
|
* Finish setting up thread glue. We need to initialize
|
|
* the thread into a td_critnest=1 state. Some platforms
|
|
* may have already partially or fully initialized td_critnest
|
|
* and/or td_md.md_savecrit (when applciable).
|
|
*
|
|
* see <arch>/<arch>/critical.c
|
|
*/
|
|
sched_lock.mtx_lock = (uintptr_t)td;
|
|
sched_lock.mtx_recurse = 0;
|
|
cpu_critical_fork_exit();
|
|
CTR3(KTR_PROC, "fork_exit: new thread %p (pid %d, %s)", td, p->p_pid,
|
|
p->p_comm);
|
|
if (PCPU_GET(switchtime.sec) == 0)
|
|
binuptime(PCPU_PTR(switchtime));
|
|
PCPU_SET(switchticks, ticks);
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
/*
|
|
* cpu_set_fork_handler intercepts this function call to
|
|
* have this call a non-return function to stay in kernel mode.
|
|
* initproc has its own fork handler, but it does return.
|
|
*/
|
|
KASSERT(callout != NULL, ("NULL callout in fork_exit"));
|
|
callout(arg, frame);
|
|
|
|
/*
|
|
* Check if a kernel thread misbehaved and returned from its main
|
|
* function.
|
|
*/
|
|
PROC_LOCK(p);
|
|
if (p->p_flag & P_KTHREAD) {
|
|
PROC_UNLOCK(p);
|
|
mtx_lock(&Giant);
|
|
printf("Kernel thread \"%s\" (pid %d) exited prematurely.\n",
|
|
p->p_comm, p->p_pid);
|
|
kthread_exit(0);
|
|
}
|
|
PROC_UNLOCK(p);
|
|
#ifdef DIAGNOSTIC
|
|
cred_free_thread(td);
|
|
#endif
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
}
|
|
|
|
/*
|
|
* Simplified back end of syscall(), used when returning from fork()
|
|
* directly into user mode. Giant is not held on entry, and must not
|
|
* be held on return. This function is passed in to fork_exit() as the
|
|
* first parameter and is called when returning to a new userland process.
|
|
*/
|
|
void
|
|
fork_return(td, frame)
|
|
struct thread *td;
|
|
struct trapframe *frame;
|
|
{
|
|
|
|
userret(td, frame, 0);
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(td, KTR_SYSRET))
|
|
ktrsysret(SYS_fork, 0, 0);
|
|
#endif
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
}
|