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4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
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38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
39 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $
40 * $DragonFly: src/sys/kern/kern_exit.c,v 1.40 2005/04/20 16:37:09 cpressey Exp $
43 #include "opt_compat.h"
44 #include "opt_ktrace.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/sysproto.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
52 #include <sys/pioctl.h>
55 #include <sys/vnode.h>
56 #include <sys/resourcevar.h>
57 #include <sys/signalvar.h>
58 #include <sys/ptrace.h>
59 #include <sys/acct.h> /* for acct_process() function prototype */
60 #include <sys/filedesc.h>
65 #include <sys/kern_syscall.h>
66 #include <sys/upcall.h>
70 #include <vm/vm_param.h>
73 #include <vm/vm_map.h>
74 #include <vm/vm_zone.h>
75 #include <vm/vm_extern.h>
78 /* Required to be non-static for SysVR4 emulator */
79 MALLOC_DEFINE(M_ZOMBIE
, "zombie", "zombie proc status");
81 static MALLOC_DEFINE(M_ATEXIT
, "atexit", "atexit callback");
84 * callout list for things to do at exit time
88 TAILQ_ENTRY(exitlist
) next
;
91 TAILQ_HEAD(exit_list_head
, exitlist
);
92 static struct exit_list_head exit_list
= TAILQ_HEAD_INITIALIZER(exit_list
);
98 * SYS_EXIT_ARGS(int rval)
101 sys_exit(struct sys_exit_args
*uap
)
103 exit1(W_EXITCODE(uap
->rval
, 0));
108 * Exit: deallocate address space and other resources, change proc state
109 * to zombie, and unlink proc from allproc and parent's lists. Save exit
110 * status and rusage for wait(). Check for child processes and orphan them.
115 struct proc
*p
= curproc
;
122 printf("init died (signal %d, exit %d)\n",
123 WTERMSIG(rv
), WEXITSTATUS(rv
));
124 panic("Going nowhere without my init!");
127 sysmsg_rundown(p
, 1);
128 caps_exit(p
->p_thread
);
131 /* are we a task leader? */
132 if(p
== p
->p_leader
) {
133 struct kill_args killArgs
;
134 killArgs
.signum
= SIGKILL
;
137 killArgs
.pid
= q
->p_pid
;
139 * The interface for kill is better
140 * than the internal signal
147 tsleep((caddr_t
)p
, 0, "exit1", 0);
153 STOPEVENT(p
, S_EXIT
, rv
);
154 wakeup(&p
->p_stype
); /* Wakeup anyone in procfs' PIOCWAIT */
157 * Check if any loadable modules need anything done at process exit.
158 * e.g. SYSV IPC stuff
159 * XXX what if one of these generates an error?
161 TAILQ_FOREACH(ep
, &exit_list
, next
)
162 (*ep
->function
)(p
->p_thread
);
164 if (p
->p_flag
& P_PROFIL
)
166 MALLOC(p
->p_ru
, struct rusage
*, sizeof(struct rusage
),
169 * If parent is waiting for us to exit or exec,
170 * P_PPWAIT is set; we will wakeup the parent below.
172 p
->p_flag
&= ~(P_TRACED
| P_PPWAIT
);
173 p
->p_flag
|= P_WEXIT
;
174 SIGEMPTYSET(p
->p_siglist
);
175 if (timevalisset(&p
->p_realtimer
.it_value
))
176 callout_stop(&p
->p_ithandle
);
179 * Reset any sigio structures pointing to us as a result of
180 * F_SETOWN with our pid.
182 funsetownlst(&p
->p_sigiolst
);
185 * Close open files and release open-file table.
191 if(p
->p_leader
->p_peers
) {
193 while(q
->p_peers
!= p
)
195 q
->p_peers
= p
->p_peers
;
196 wakeup((caddr_t
)p
->p_leader
);
200 * XXX Shutdown SYSV semaphores
204 KKASSERT(p
->p_numposixlocks
== 0);
206 /* The next two chunks should probably be moved to vmspace_exit. */
210 * Release upcalls associated with this process
216 * Release user portion of address space.
217 * This releases references to vnodes,
218 * which could cause I/O if the file has been unlinked.
219 * Need to do this early enough that we can still sleep.
220 * Can't free the entire vmspace as the kernel stack
221 * may be mapped within that space also.
223 * Processes sharing the same vmspace may exit in one order, and
224 * get cleaned up by vmspace_exit() in a different order. The
225 * last exiting process to reach this point releases as much of
226 * the environment as it can, and the last process cleaned up
227 * by vmspace_exit() (which decrements exitingcnt) cleans up the
231 if (--vm
->vm_refcnt
== 0) {
233 pmap_remove_pages(vmspace_pmap(vm
), VM_MIN_ADDRESS
,
235 (void) vm_map_remove(&vm
->vm_map
, VM_MIN_ADDRESS
,
239 if (SESS_LEADER(p
)) {
240 struct session
*sp
= p
->p_session
;
245 * We are the controlling process. Signal the
246 * foreground process group, drain the controlling
247 * terminal, and revoke access to the controlling
250 * NOTE: while waiting for the process group to exit
251 * it is possible that one of the processes in the
252 * group will revoke the tty, so we have to recheck.
254 if (sp
->s_ttyp
&& (sp
->s_ttyp
->t_session
== sp
)) {
255 if (sp
->s_ttyp
->t_pgrp
)
256 pgsignal(sp
->s_ttyp
->t_pgrp
, SIGHUP
, 1);
257 (void) ttywait(sp
->s_ttyp
);
259 * The tty could have been revoked
262 if ((vp
= sp
->s_ttyvp
) != NULL
) {
263 ttyclosesession(sp
, 0);
264 if (vx_lock(vp
) == 0) {
265 VOP_REVOKE(vp
, REVOKEALL
);
268 vrele(vp
); /* s_ttyvp ref */
272 * Release the tty. If someone has it open via
273 * /dev/tty then close it (since they no longer can
274 * once we've NULL'd it out).
277 ttyclosesession(sp
, 1);
279 * s_ttyp is not zero'd; we use this to indicate
280 * that the session once had a controlling terminal.
281 * (for logging and informational purposes)
286 fixjobc(p
, p
->p_pgrp
, 0);
287 (void)acct_process(p
);
292 p
->p_traceflag
= 0; /* don't trace the vrele() */
293 if ((vtmp
= p
->p_tracep
) != NULL
) {
299 * Release reference to text vnode
301 if ((vtmp
= p
->p_textvp
) != NULL
) {
307 * Once we set SZOMB the process can get reaped. The wait1 code
308 * will also wait for TDF_RUNNING to be cleared in the thread's flags,
309 * indicating that it has been completely switched out.
313 * Remove proc from allproc queue and pidhash chain.
314 * Place onto zombproc. Unlink from parent's child list.
316 LIST_REMOVE(p
, p_list
);
317 LIST_INSERT_HEAD(&zombproc
, p
, p_list
);
320 LIST_REMOVE(p
, p_hash
);
322 q
= LIST_FIRST(&p
->p_children
);
323 if (q
) /* only need this if any child is S_ZOMB */
324 wakeup((caddr_t
) initproc
);
325 for (; q
!= 0; q
= nq
) {
326 nq
= LIST_NEXT(q
, p_sibling
);
327 LIST_REMOVE(q
, p_sibling
);
328 LIST_INSERT_HEAD(&initproc
->p_children
, q
, p_sibling
);
329 q
->p_pptr
= initproc
;
330 q
->p_sigparent
= SIGCHLD
;
332 * Traced processes are killed
333 * since their existence means someone is screwing up.
335 if (q
->p_flag
& P_TRACED
) {
336 q
->p_flag
&= ~P_TRACED
;
342 * Save exit status and final rusage info, adding in child rusage
343 * info and self times.
346 *p
->p_ru
= p
->p_stats
->p_ru
;
347 calcru(p
, &p
->p_ru
->ru_utime
, &p
->p_ru
->ru_stime
, NULL
);
348 ruadd(p
->p_ru
, &p
->p_stats
->p_cru
);
351 * notify interested parties of our demise.
353 KNOTE(&p
->p_klist
, NOTE_EXIT
);
356 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
357 * flag set, notify process 1 instead (and hope it will handle
360 if (p
->p_pptr
->p_procsig
->ps_flag
& PS_NOCLDWAIT
) {
361 struct proc
*pp
= p
->p_pptr
;
362 proc_reparent(p
, initproc
);
364 * If this was the last child of our parent, notify
365 * parent, so in case he was wait(2)ing, he will
368 if (LIST_EMPTY(&pp
->p_children
))
372 if (p
->p_sigparent
&& p
->p_pptr
!= initproc
) {
373 psignal(p
->p_pptr
, p
->p_sigparent
);
375 psignal(p
->p_pptr
, SIGCHLD
);
378 wakeup((caddr_t
)p
->p_pptr
);
380 /* move this to cpu_exit */
381 p
->p_thread
->td_pcb
->pcb_saveacc
.faddr
= (float *)NULL
;
384 * cpu_exit is responsible for clearing curproc, since
385 * it is heavily integrated with the thread/switching sequence.
387 * Other substructures are freed from wait().
389 if (--p
->p_limit
->p_refcnt
== 0) {
390 FREE(p
->p_limit
, M_SUBPROC
);
395 * Release the current user process designation on the process so
396 * the userland scheduler can work in someone else.
401 * Finally, call machine-dependent code to release the remaining
402 * resources including address space, the kernel stack and pcb.
403 * The address space is released by "vmspace_free(p->p_vmspace)";
404 * This is machine-dependent, as we may have to change stacks
405 * or ensure that the current one isn't reallocated before we
406 * finish. cpu_exit will end with a call to cpu_switch(), finishing
407 * our execution (pun intended).
413 wait4(struct wait_args
*uap
)
415 struct rusage rusage
;
418 error
= kern_wait(uap
->pid
, uap
->status
? &status
: NULL
,
419 uap
->options
, uap
->rusage
? &rusage
: NULL
, &uap
->sysmsg_fds
[0]);
421 if (error
== 0 && uap
->status
)
422 error
= copyout(&status
, uap
->status
, sizeof(*uap
->status
));
423 if (error
== 0 && uap
->rusage
)
424 error
= copyout(&rusage
, uap
->rusage
, sizeof(*uap
->rusage
));
431 * wait_args(int pid, int *status, int options, struct rusage *rusage)
434 kern_wait(pid_t pid
, int *status
, int options
, struct rusage
*rusage
, int *res
)
436 struct thread
*td
= curthread
;
437 struct proc
*q
= td
->td_proc
;
443 if (options
&~ (WUNTRACED
|WNOHANG
|WLINUXCLONE
))
447 LIST_FOREACH(p
, &q
->p_children
, p_sibling
) {
448 if (pid
!= WAIT_ANY
&&
449 p
->p_pid
!= pid
&& p
->p_pgid
!= -pid
)
452 /* This special case handles a kthread spawned by linux_clone
453 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
454 * need to be able to distinguish between waiting on a process and
455 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
456 * and the WLINUXCLONE option signifies we want to wait for threads
459 if ((p
->p_sigparent
!= SIGCHLD
) ^ ((options
& WLINUXCLONE
) != 0))
463 if (p
->p_stat
== SZOMB
) {
465 * The process's thread may still be in the middle
466 * of switching away, we can't rip its stack out from
467 * under it until TDF_RUNNING clears!
469 * YYY no wakeup occurs so we depend on the timeout.
471 if ((p
->p_thread
->td_flags
& TDF_RUNNING
) != 0) {
472 tsleep(p
->p_thread
, 0, "reap", 1);
477 * Other kernel threads may be in the middle of
478 * accessing the proc. For example, kern/kern_proc.c
479 * could be blocked writing proc data to a sysctl.
480 * At the moment, if this occurs, we are not woken
481 * up and rely on a one-second retry.
485 tsleep(p
, 0, "reap2", hz
);
487 lwkt_wait_free(p
->p_thread
);
490 * Charge the parent for the child's change in
491 * estimated cpu as of when the child exits to
492 * account for batch scripts, large make's, etc.
495 if (p
->p_estcpu
> p
->p_estcpu_fork
) {
496 q
->p_estcpu
= ESTCPULIM(q
->p_estcpu
+
497 p
->p_estcpu
- p
->p_estcpu_fork
);
501 /* Take care of our return values. */
504 *status
= p
->p_xstat
;
508 * If we got the child via a ptrace 'attach',
509 * we need to give it back to the old parent.
511 if (p
->p_oppid
&& (t
= pfind(p
->p_oppid
))) {
519 ruadd(&q
->p_stats
->p_cru
, p
->p_ru
);
520 FREE(p
->p_ru
, M_ZOMBIE
);
524 * Decrement the count of procs running with this uid.
526 chgproccnt(p
->p_ucred
->cr_ruidinfo
, -1, 0);
529 * Free up credentials.
535 * Remove unused arguments
537 if (p
->p_args
&& --p
->p_args
->ar_ref
== 0)
538 FREE(p
->p_args
, M_PARGS
);
541 * Finally finished with old proc entry.
542 * Unlink it from its process group and free it.
545 LIST_REMOVE(p
, p_list
); /* off zombproc */
546 LIST_REMOVE(p
, p_sibling
);
548 if (--p
->p_procsig
->ps_refcnt
== 0) {
549 if (p
->p_sigacts
!= &p
->p_addr
->u_sigacts
)
550 FREE(p
->p_sigacts
, M_SUBPROC
);
551 FREE(p
->p_procsig
, M_SUBPROC
);
560 if (p
->p_stat
== SSTOP
&& (p
->p_flag
& P_WAITED
) == 0 &&
561 (p
->p_flag
& P_TRACED
|| options
& WUNTRACED
)) {
562 p
->p_flag
|= P_WAITED
;
566 *status
= W_STOPCODE(p
->p_xstat
);
567 /* Zero rusage so we get something consistent. */
569 bzero(rusage
, sizeof(rusage
));
575 if (options
& WNOHANG
) {
579 error
= tsleep((caddr_t
)q
, PCATCH
, "wait", 0);
586 * make process 'parent' the new parent of process 'child'.
589 proc_reparent(struct proc
*child
, struct proc
*parent
)
592 if (child
->p_pptr
== parent
)
595 LIST_REMOVE(child
, p_sibling
);
596 LIST_INSERT_HEAD(&parent
->p_children
, child
, p_sibling
);
597 child
->p_pptr
= parent
;
601 * The next two functions are to handle adding/deleting items on the
605 * Take the arguments given and put them onto the exit callout list,
606 * However first make sure that it's not already there.
607 * returns 0 on success.
611 at_exit(exitlist_fn function
)
616 /* Be noisy if the programmer has lost track of things */
617 if (rm_at_exit(function
))
618 printf("WARNING: exit callout entry (%p) already present\n",
621 ep
= malloc(sizeof(*ep
), M_ATEXIT
, M_NOWAIT
);
624 ep
->function
= function
;
625 TAILQ_INSERT_TAIL(&exit_list
, ep
, next
);
630 * Scan the exit callout list for the given item and remove it.
631 * Returns the number of items removed (0 or 1)
634 rm_at_exit(exitlist_fn function
)
638 TAILQ_FOREACH(ep
, &exit_list
, next
) {
639 if (ep
->function
== function
) {
640 TAILQ_REMOVE(&exit_list
, ep
, next
);
651 struct proc
*p
= curproc
;
655 if (p
->p_procsig
->ps_refcnt
== 1 &&
656 p
->p_sigacts
!= &p
->p_addr
->u_sigacts
) {
659 p
->p_addr
->u_sigacts
= *pss
;
660 p
->p_sigacts
= &p
->p_addr
->u_sigacts
;
662 FREE(pss
, M_SUBPROC
);