freebsd-skq/sys/kern/kern_exit.c
julian e8efa7328e Reversion of commit by Davidxu plus fixes since applied.
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.
2003-02-01 12:17:09 +00:00

880 lines
22 KiB
C

/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
* $FreeBSD$
*/
#include "opt_compat.h"
#include "opt_ktrace.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/tty.h>
#include <sys/wait.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/sched.h>
#include <sys/sx.h>
#include <sys/ptrace.h>
#include <sys/acct.h> /* for acct_process() function prototype */
#include <sys/filedesc.h>
#include <sys/mac.h>
#include <sys/shm.h>
#include <sys/sem.h>
#include <sys/jail.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/uma.h>
#include <sys/user.h>
/* Required to be non-static for SysVR4 emulator */
MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
static int wait1(struct thread *, struct wait_args *, int);
/*
* callout list for things to do at exit time
*/
struct exitlist {
exitlist_fn function;
TAILQ_ENTRY(exitlist) next;
};
TAILQ_HEAD(exit_list_head, exitlist);
static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
/*
* exit --
* Death of process.
*
* MPSAFE
*/
void
sys_exit(td, uap)
struct thread *td;
struct sys_exit_args /* {
int rval;
} */ *uap;
{
mtx_lock(&Giant);
exit1(td, W_EXITCODE(uap->rval, 0));
/* NOTREACHED */
}
/*
* Exit: deallocate address space and other resources, change proc state
* to zombie, and unlink proc from allproc and parent's lists. Save exit
* status and rusage for wait(). Check for child processes and orphan them.
*/
void
exit1(td, rv)
register struct thread *td;
int rv;
{
struct exitlist *ep;
struct proc *p, *nq, *q;
struct tty *tp;
struct vnode *ttyvp;
register struct vmspace *vm;
struct vnode *vtmp;
#ifdef KTRACE
struct vnode *tracevp;
#endif
GIANT_REQUIRED;
p = td->td_proc;
if (p == initproc) {
printf("init died (signal %d, exit %d)\n",
WTERMSIG(rv), WEXITSTATUS(rv));
panic("Going nowhere without my init!");
}
/*
* XXXXKSE: MUST abort all other threads before proceeding past here.
*/
PROC_LOCK(p);
if (p->p_flag & P_KSES) {
/*
* First check if some other thread got here before us..
* if so, act apropriatly, (exit or suspend);
*/
thread_suspend_check(0);
/*
* Here is a trick..
* We need to free up our KSE to process other threads
* so that we can safely set the UNBOUND flag
* (whether or not we have a mailbox) as we are NEVER
* going to return to the user.
* The flag will not be set yet if we are exiting
* because of a signal, pagefault, or similar
* (or even an exit(2) from the UTS).
*/
td->td_flags |= TDF_UNBOUND;
/*
* Kill off the other threads. This requires
* Some co-operation from other parts of the kernel
* so it may not be instant.
* With this state set:
* Any thread entering the kernel from userspace will
* thread_exit() in trap(). Any thread attempting to
* sleep will return immediatly
* with EINTR or EWOULDBLOCK, which will hopefully force them
* to back out to userland, freeing resources as they go, and
* anything attempting to return to userland will thread_exit()
* from userret(). thread_exit() will unsuspend us
* when the last other thread exits.
*/
if (thread_single(SINGLE_EXIT)) {
panic ("Exit: Single threading fouled up");
}
/*
* All other activity in this process is now stopped.
* Remove excess KSEs and KSEGRPS. XXXKSE (when we have them)
* ...
* Turn off threading support.
*/
p->p_flag &= ~P_KSES;
td->td_flags &= ~TDF_UNBOUND;
thread_single_end(); /* Don't need this any more. */
}
/*
* With this state set:
* Any thread entering the kernel from userspace will thread_exit()
* in trap(). Any thread attempting to sleep will return immediatly
* with EINTR or EWOULDBLOCK, which will hopefully force them
* to back out to userland, freeing resources as they go, and
* anything attempting to return to userland will thread_exit()
* from userret(). thread_exit() will do a wakeup on p->p_numthreads
* if it transitions to 1.
*/
p->p_flag |= P_WEXIT;
PROC_UNLOCK(p);
/* Are we a task leader? */
if (p == p->p_leader) {
mtx_lock(&ppeers_lock);
q = p->p_peers;
while (q != NULL) {
PROC_LOCK(q);
psignal(q, SIGKILL);
PROC_UNLOCK(q);
q = q->p_peers;
}
while (p->p_peers != NULL)
msleep(p, &ppeers_lock, PWAIT, "exit1", 0);
mtx_unlock(&ppeers_lock);
}
#ifdef PGINPROF
vmsizmon();
#endif
STOPEVENT(p, S_EXIT, rv);
wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */
/*
* Check if any loadable modules need anything done at process exit.
* e.g. SYSV IPC stuff
* XXX what if one of these generates an error?
*/
TAILQ_FOREACH(ep, &exit_list, next)
(*ep->function)(p);
stopprofclock(p);
MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
M_ZOMBIE, 0);
/*
* If parent is waiting for us to exit or exec,
* P_PPWAIT is set; we will wakeup the parent below.
*/
PROC_LOCK(p);
p->p_flag &= ~(P_TRACED | P_PPWAIT);
SIGEMPTYSET(p->p_siglist);
PROC_UNLOCK(p);
if (timevalisset(&p->p_realtimer.it_value))
callout_stop(&p->p_itcallout);
/*
* Reset any sigio structures pointing to us as a result of
* F_SETOWN with our pid.
*/
funsetownlst(&p->p_sigiolst);
/*
* Close open files and release open-file table.
* This may block!
*/
fdfree(td); /* XXXKSE *//* may not be the one in proc */
/*
* Remove ourself from our leader's peer list and wake our leader.
*/
mtx_lock(&ppeers_lock);
if (p->p_leader->p_peers) {
q = p->p_leader;
while (q->p_peers != p)
q = q->p_peers;
q->p_peers = p->p_peers;
wakeup(p->p_leader);
}
mtx_unlock(&ppeers_lock);
/* The next two chunks should probably be moved to vmspace_exit. */
vm = p->p_vmspace;
/*
* Release user portion of address space.
* This releases references to vnodes,
* which could cause I/O if the file has been unlinked.
* Need to do this early enough that we can still sleep.
* Can't free the entire vmspace as the kernel stack
* may be mapped within that space also.
*
* Processes sharing the same vmspace may exit in one order, and
* get cleaned up by vmspace_exit() in a different order. The
* last exiting process to reach this point releases as much of
* the environment as it can, and the last process cleaned up
* by vmspace_exit() (which decrements exitingcnt) cleans up the
* remainder.
*/
++vm->vm_exitingcnt;
if (--vm->vm_refcnt == 0) {
shmexit(vm);
vm_page_lock_queues();
pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map),
vm_map_max(&vm->vm_map));
vm_page_unlock_queues();
(void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
vm_map_max(&vm->vm_map));
}
sx_xlock(&proctree_lock);
if (SESS_LEADER(p)) {
register struct session *sp;
sp = p->p_session;
if (sp->s_ttyvp) {
/*
* Controlling process.
* Signal foreground pgrp,
* drain controlling terminal
* and revoke access to controlling terminal.
*/
if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
tp = sp->s_ttyp;
if (sp->s_ttyp->t_pgrp) {
PGRP_LOCK(sp->s_ttyp->t_pgrp);
pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
PGRP_UNLOCK(sp->s_ttyp->t_pgrp);
}
/* XXX tp should be locked. */
sx_xunlock(&proctree_lock);
(void) ttywait(tp);
sx_xlock(&proctree_lock);
/*
* The tty could have been revoked
* if we blocked.
*/
if (sp->s_ttyvp) {
ttyvp = sp->s_ttyvp;
SESS_LOCK(p->p_session);
sp->s_ttyvp = NULL;
SESS_UNLOCK(p->p_session);
sx_xunlock(&proctree_lock);
VOP_REVOKE(ttyvp, REVOKEALL);
vrele(ttyvp);
sx_xlock(&proctree_lock);
}
}
if (sp->s_ttyvp) {
ttyvp = sp->s_ttyvp;
SESS_LOCK(p->p_session);
sp->s_ttyvp = NULL;
SESS_UNLOCK(p->p_session);
vrele(ttyvp);
}
/*
* s_ttyp is not zero'd; we use this to indicate
* that the session once had a controlling terminal.
* (for logging and informational purposes)
*/
}
SESS_LOCK(p->p_session);
sp->s_leader = NULL;
SESS_UNLOCK(p->p_session);
}
fixjobc(p, p->p_pgrp, 0);
sx_xunlock(&proctree_lock);
(void)acct_process(td);
#ifdef KTRACE
/*
* release trace file
*/
PROC_LOCK(p);
mtx_lock(&ktrace_mtx);
p->p_traceflag = 0; /* don't trace the vrele() */
tracevp = p->p_tracep;
p->p_tracep = NULL;
mtx_unlock(&ktrace_mtx);
PROC_UNLOCK(p);
if (tracevp != NULL)
vrele(tracevp);
#endif
/*
* Release reference to text vnode
*/
if ((vtmp = p->p_textvp) != NULL) {
p->p_textvp = NULL;
vrele(vtmp);
}
/*
* Release our limits structure.
*/
mtx_assert(&Giant, MA_OWNED);
if (--p->p_limit->p_refcnt == 0) {
FREE(p->p_limit, M_SUBPROC);
p->p_limit = NULL;
}
/*
* Release this thread's reference to the ucred. The actual proc
* reference will stay around until the proc is harvested by
* wait(). At this point the ucred is immutable (no other threads
* from this proc are around that can change it) so we leave the
* per-thread ucred pointer intact in case it is needed although
* in theory nothing should be using it at this point.
*/
crfree(td->td_ucred);
/*
* Remove proc from allproc queue and pidhash chain.
* Place onto zombproc. Unlink from parent's child list.
*/
sx_xlock(&allproc_lock);
LIST_REMOVE(p, p_list);
LIST_INSERT_HEAD(&zombproc, p, p_list);
LIST_REMOVE(p, p_hash);
sx_xunlock(&allproc_lock);
sx_xlock(&proctree_lock);
q = LIST_FIRST(&p->p_children);
if (q != NULL) /* only need this if any child is S_ZOMB */
wakeup(initproc);
for (; q != NULL; q = nq) {
nq = LIST_NEXT(q, p_sibling);
PROC_LOCK(q);
proc_reparent(q, initproc);
q->p_sigparent = SIGCHLD;
/*
* Traced processes are killed
* since their existence means someone is screwing up.
*/
if (q->p_flag & P_TRACED) {
q->p_flag &= ~P_TRACED;
psignal(q, SIGKILL);
}
PROC_UNLOCK(q);
}
/*
* Save exit status and final rusage info, adding in child rusage
* info and self times.
*/
PROC_LOCK(p);
p->p_xstat = rv;
*p->p_ru = p->p_stats->p_ru;
mtx_lock_spin(&sched_lock);
calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
mtx_unlock_spin(&sched_lock);
ruadd(p->p_ru, &p->p_stats->p_cru);
/*
* Notify interested parties of our demise.
*/
KNOTE(&p->p_klist, NOTE_EXIT);
/*
* Notify parent that we're gone. If parent has the PS_NOCLDWAIT
* flag set, or if the handler is set to SIG_IGN, notify process
* 1 instead (and hope it will handle this situation).
*/
PROC_LOCK(p->p_pptr);
if (p->p_pptr->p_procsig->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
struct proc *pp;
pp = p->p_pptr;
PROC_UNLOCK(pp);
proc_reparent(p, initproc);
PROC_LOCK(p->p_pptr);
/*
* If this was the last child of our parent, notify
* parent, so in case he was wait(2)ing, he will
* continue.
*/
if (LIST_EMPTY(&pp->p_children))
wakeup(pp);
}
if (p->p_sigparent && p->p_pptr != initproc)
psignal(p->p_pptr, p->p_sigparent);
else
psignal(p->p_pptr, SIGCHLD);
PROC_UNLOCK(p->p_pptr);
/*
* If this is a kthread, then wakeup anyone waiting for it to exit.
*/
if (p->p_flag & P_KTHREAD)
wakeup(p);
PROC_UNLOCK(p);
/*
* Finally, call machine-dependent code to release the remaining
* resources including address space.
* The address space is released by "vmspace_exitfree(p)" in
* vm_waitproc().
*/
cpu_exit(td);
PROC_LOCK(p);
PROC_LOCK(p->p_pptr);
sx_xunlock(&proctree_lock);
mtx_lock_spin(&sched_lock);
while (mtx_owned(&Giant))
mtx_unlock(&Giant);
/*
* We have to wait until after releasing all locks before
* changing p_state. If we block on a mutex then we will be
* back at SRUN when we resume and our parent will never
* harvest us.
*/
p->p_state = PRS_ZOMBIE;
wakeup(p->p_pptr);
PROC_UNLOCK(p->p_pptr);
cnt.v_swtch++;
binuptime(PCPU_PTR(switchtime));
PCPU_SET(switchticks, ticks);
cpu_sched_exit(td); /* XXXKSE check if this should be in thread_exit */
/*
* Make sure the scheduler takes this thread out of its tables etc.
* This will also release this thread's reference to the ucred.
* Other thread parts to release include pcb bits and such.
*/
thread_exit();
}
#ifdef COMPAT_43
/*
* MPSAFE. The dirty work is handled by wait1().
*/
int
owait(td, uap)
struct thread *td;
register struct owait_args /* {
int dummy;
} */ *uap;
{
struct wait_args w;
w.options = 0;
w.rusage = NULL;
w.pid = WAIT_ANY;
w.status = NULL;
return (wait1(td, &w, 1));
}
#endif /* COMPAT_43 */
/*
* MPSAFE. The dirty work is handled by wait1().
*/
int
wait4(td, uap)
struct thread *td;
struct wait_args *uap;
{
return (wait1(td, uap, 0));
}
/*
* MPSAFE
*/
static int
wait1(td, uap, compat)
register struct thread *td;
register struct wait_args /* {
int pid;
int *status;
int options;
struct rusage *rusage;
} */ *uap;
int compat;
{
struct rusage ru;
int nfound;
struct proc *p, *q, *t;
int status, error;
q = td->td_proc;
if (uap->pid == 0) {
PROC_LOCK(q);
uap->pid = -q->p_pgid;
PROC_UNLOCK(q);
}
if (uap->options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
return (EINVAL);
mtx_lock(&Giant);
loop:
nfound = 0;
sx_xlock(&proctree_lock);
LIST_FOREACH(p, &q->p_children, p_sibling) {
PROC_LOCK(p);
if (uap->pid != WAIT_ANY &&
p->p_pid != uap->pid && p->p_pgid != -uap->pid) {
PROC_UNLOCK(p);
continue;
}
/*
* This special case handles a kthread spawned by linux_clone
* (see linux_misc.c). The linux_wait4 and linux_waitpid
* functions need to be able to distinguish between waiting
* on a process and waiting on a thread. It is a thread if
* p_sigparent is not SIGCHLD, and the WLINUXCLONE option
* signifies we want to wait for threads and not processes.
*/
if ((p->p_sigparent != SIGCHLD) ^
((uap->options & WLINUXCLONE) != 0)) {
PROC_UNLOCK(p);
continue;
}
nfound++;
if (p->p_state == PRS_ZOMBIE) {
/*
* Allow the scheduler to adjust the priority of the
* parent when a kseg is exiting.
*/
if (curthread->td_proc->p_pid != 1) {
mtx_lock_spin(&sched_lock);
sched_exit(curthread->td_ksegrp,
FIRST_KSEGRP_IN_PROC(p));
mtx_unlock_spin(&sched_lock);
}
td->td_retval[0] = p->p_pid;
#ifdef COMPAT_43
if (compat)
td->td_retval[1] = p->p_xstat;
else
#endif
if (uap->status) {
status = p->p_xstat; /* convert to int */
PROC_UNLOCK(p);
if ((error = copyout(&status,
uap->status, sizeof(status)))) {
sx_xunlock(&proctree_lock);
mtx_unlock(&Giant);
return (error);
}
PROC_LOCK(p);
}
if (uap->rusage) {
bcopy(p->p_ru, &ru, sizeof(ru));
PROC_UNLOCK(p);
if ((error = copyout(&ru,
uap->rusage, sizeof (struct rusage)))) {
sx_xunlock(&proctree_lock);
mtx_unlock(&Giant);
return (error);
}
} else
PROC_UNLOCK(p);
/*
* If we got the child via a ptrace 'attach',
* we need to give it back to the old parent.
*/
if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
PROC_LOCK(p);
p->p_oppid = 0;
proc_reparent(p, t);
PROC_UNLOCK(p);
psignal(t, SIGCHLD);
wakeup(t);
PROC_UNLOCK(t);
sx_xunlock(&proctree_lock);
mtx_unlock(&Giant);
return (0);
}
/*
* Remove other references to this process to ensure
* we have an exclusive reference.
*/
leavepgrp(p);
sx_xlock(&allproc_lock);
LIST_REMOVE(p, p_list); /* off zombproc */
sx_xunlock(&allproc_lock);
LIST_REMOVE(p, p_sibling);
sx_xunlock(&proctree_lock);
/*
* As a side effect of this lock, we know that
* all other writes to this proc are visible now, so
* no more locking is needed for p.
*/
PROC_LOCK(p);
p->p_xstat = 0; /* XXX: why? */
PROC_UNLOCK(p);
PROC_LOCK(q);
ruadd(&q->p_stats->p_cru, p->p_ru);
PROC_UNLOCK(q);
FREE(p->p_ru, M_ZOMBIE);
p->p_ru = NULL;
/*
* Decrement the count of procs running with this uid.
*/
(void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
/*
* Free up credentials.
*/
crfree(p->p_ucred);
p->p_ucred = NULL; /* XXX: why? */
/*
* Remove unused arguments
*/
pargs_drop(p->p_args);
p->p_args = NULL;
if (--p->p_procsig->ps_refcnt == 0) {
if (p->p_sigacts != &p->p_uarea->u_sigacts)
FREE(p->p_sigacts, M_SUBPROC);
FREE(p->p_procsig, M_SUBPROC);
p->p_procsig = NULL;
}
/*
* do any thread-system specific cleanups
*/
thread_wait(p);
/*
* Give vm and machine-dependent layer a chance
* to free anything that cpu_exit couldn't
* release while still running in process context.
*/
vm_waitproc(p);
mtx_destroy(&p->p_mtx);
#ifdef MAC
mac_destroy_proc(p);
#endif
KASSERT(FIRST_THREAD_IN_PROC(p),
("wait1: no residual thread!"));
uma_zfree(proc_zone, p);
sx_xlock(&allproc_lock);
nprocs--;
sx_xunlock(&allproc_lock);
mtx_unlock(&Giant);
return (0);
}
if (P_SHOULDSTOP(p) && ((p->p_flag & P_WAITED) == 0) &&
(p->p_flag & P_TRACED || uap->options & WUNTRACED)) {
p->p_flag |= P_WAITED;
sx_xunlock(&proctree_lock);
td->td_retval[0] = p->p_pid;
#ifdef COMPAT_43
if (compat) {
td->td_retval[1] = W_STOPCODE(p->p_xstat);
PROC_UNLOCK(p);
error = 0;
} else
#endif
if (uap->status) {
status = W_STOPCODE(p->p_xstat);
PROC_UNLOCK(p);
error = copyout(&status,
uap->status, sizeof(status));
} else {
PROC_UNLOCK(p);
error = 0;
}
mtx_unlock(&Giant);
return (error);
}
if (uap->options & WCONTINUED && (p->p_flag & P_CONTINUED)) {
sx_xunlock(&proctree_lock);
td->td_retval[0] = p->p_pid;
p->p_flag &= ~P_CONTINUED;
PROC_UNLOCK(p);
if (uap->status) {
status = SIGCONT;
error = copyout(&status,
uap->status, sizeof(status));
} else
error = 0;
mtx_unlock(&Giant);
return (error);
}
PROC_UNLOCK(p);
}
if (nfound == 0) {
sx_xunlock(&proctree_lock);
mtx_unlock(&Giant);
return (ECHILD);
}
if (uap->options & WNOHANG) {
sx_xunlock(&proctree_lock);
td->td_retval[0] = 0;
mtx_unlock(&Giant);
return (0);
}
PROC_LOCK(q);
sx_xunlock(&proctree_lock);
error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0);
PROC_UNLOCK(q);
if (error) {
mtx_unlock(&Giant);
return (error);
}
goto loop;
}
/*
* Make process 'parent' the new parent of process 'child'.
* Must be called with an exclusive hold of proctree lock.
*/
void
proc_reparent(child, parent)
register struct proc *child;
register struct proc *parent;
{
sx_assert(&proctree_lock, SX_XLOCKED);
PROC_LOCK_ASSERT(child, MA_OWNED);
if (child->p_pptr == parent)
return;
LIST_REMOVE(child, p_sibling);
LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
child->p_pptr = parent;
}
/*
* The next two functions are to handle adding/deleting items on the
* exit callout list
*
* at_exit():
* Take the arguments given and put them onto the exit callout list,
* However first make sure that it's not already there.
* returns 0 on success.
*/
int
at_exit(function)
exitlist_fn function;
{
struct exitlist *ep;
#ifdef INVARIANTS
/* Be noisy if the programmer has lost track of things */
if (rm_at_exit(function))
printf("WARNING: exit callout entry (%p) already present\n",
function);
#endif
ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
if (ep == NULL)
return (ENOMEM);
ep->function = function;
TAILQ_INSERT_TAIL(&exit_list, ep, next);
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_exit(function)
exitlist_fn function;
{
struct exitlist *ep;
TAILQ_FOREACH(ep, &exit_list, next) {
if (ep->function == function) {
TAILQ_REMOVE(&exit_list, ep, next);
free(ep, M_ATEXIT);
return (1);
}
}
return (0);
}