/
kern_exit.c
1317 lines (1171 loc) · 32.5 KB
/
kern_exit.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* $NetBSD: kern_exit.c,v 1.276 2019/06/13 20:20:18 kamil Exp $ */
/*-
* Copyright (c) 1998, 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, and by Andrew Doran.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* 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. 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 8.10 (Berkeley) 2/23/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.276 2019/06/13 20:20:18 kamil Exp $");
#include "opt_ktrace.h"
#include "opt_dtrace.h"
#include "opt_sysv.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <sys/fstrans.h>
#include <sys/vnode.h>
#include <sys/syslog.h>
#include <sys/pool.h>
#include <sys/uidinfo.h>
#include <sys/ptrace.h>
#include <sys/acct.h>
#include <sys/filedesc.h>
#include <sys/ras.h>
#include <sys/signalvar.h>
#include <sys/sched.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <sys/kauth.h>
#include <sys/sleepq.h>
#include <sys/lockdebug.h>
#include <sys/ktrace.h>
#include <sys/cpu.h>
#include <sys/lwpctl.h>
#include <sys/atomic.h>
#include <sys/sdt.h>
#include <sys/psref.h>
#include <uvm/uvm_extern.h>
#ifdef DEBUG_EXIT
int debug_exit = 0;
#define DPRINTF(x) if (debug_exit) printf x
#else
#define DPRINTF(x)
#endif
static int find_stopped_child(struct proc *, idtype_t, id_t, int,
struct proc **, struct wrusage *, siginfo_t *);
static void proc_free(struct proc *, struct wrusage *);
/*
* DTrace SDT provider definitions
*/
SDT_PROVIDER_DECLARE(proc);
SDT_PROBE_DEFINE1(proc, kernel, , exit, "int");
/*
* Fill in the appropriate signal information, and signal the parent.
*/
/* XXX noclone works around a gcc 4.5 bug on arm */
static void __noclone
exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi)
{
KSI_INIT(ksi);
if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) {
if (p->p_xsig) {
if (p->p_sflag & PS_COREDUMP)
ksi->ksi_code = CLD_DUMPED;
else
ksi->ksi_code = CLD_KILLED;
ksi->ksi_status = p->p_xsig;
} else {
ksi->ksi_code = CLD_EXITED;
ksi->ksi_status = p->p_xexit;
}
} else {
ksi->ksi_code = SI_USER;
ksi->ksi_status = p->p_xsig;
}
/*
* We fill those in, even for non-SIGCHLD.
* It's safe to access p->p_cred unlocked here.
*/
ksi->ksi_pid = p->p_pid;
ksi->ksi_uid = kauth_cred_geteuid(p->p_cred);
/* XXX: is this still valid? */
ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec;
ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec;
}
/*
* exit --
* Death of process.
*/
int
sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval)
{
/* {
syscallarg(int) rval;
} */
struct proc *p = l->l_proc;
/* Don't call exit1() multiple times in the same process. */
mutex_enter(p->p_lock);
if (p->p_sflag & PS_WEXIT) {
mutex_exit(p->p_lock);
lwp_exit(l);
}
/* exit1() will release the mutex. */
exit1(l, SCARG(uap, rval), 0);
/* NOTREACHED */
return (0);
}
/*
* 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.
*
* Must be called with p->p_lock held. Does not return.
*/
void
exit1(struct lwp *l, int exitcode, int signo)
{
struct proc *p, *child, *next_child, *old_parent, *new_parent;
struct pgrp *pgrp;
ksiginfo_t ksi;
ksiginfoq_t kq;
int wakeinit;
p = l->l_proc;
KASSERT(mutex_owned(p->p_lock));
KASSERT(p->p_vmspace != NULL);
if (__predict_false(p == initproc)) {
panic("init died (signal %d, exit %d)", signo, exitcode);
}
p->p_sflag |= PS_WEXIT;
/*
* Force all other LWPs to exit before we do. Only then can we
* begin to tear down the rest of the process state.
*/
if (p->p_nlwps > 1) {
exit_lwps(l);
}
ksiginfo_queue_init(&kq);
/*
* If we have been asked to stop on exit, do so now.
*/
if (__predict_false(p->p_sflag & PS_STOPEXIT)) {
KERNEL_UNLOCK_ALL(l, &l->l_biglocks);
sigclearall(p, &contsigmask, &kq);
if (!mutex_tryenter(proc_lock)) {
mutex_exit(p->p_lock);
mutex_enter(proc_lock);
mutex_enter(p->p_lock);
}
p->p_waited = 0;
p->p_pptr->p_nstopchild++;
p->p_stat = SSTOP;
mutex_exit(proc_lock);
lwp_lock(l);
p->p_nrlwps--;
l->l_stat = LSSTOP;
lwp_unlock(l);
mutex_exit(p->p_lock);
lwp_lock(l);
mi_switch(l);
KERNEL_LOCK(l->l_biglocks, l);
mutex_enter(p->p_lock);
}
/*
* Bin any remaining signals and mark the process as dying so it will
* not be found for, e.g. signals.
*/
sigfillset(&p->p_sigctx.ps_sigignore);
sigclearall(p, NULL, &kq);
p->p_stat = SDYING;
mutex_exit(p->p_lock);
ksiginfo_queue_drain(&kq);
/* Destroy any lwpctl info. */
if (p->p_lwpctl != NULL)
lwp_ctl_exit();
/*
* Drain all remaining references that procfs, ptrace and others may
* have on the process.
*/
rw_enter(&p->p_reflock, RW_WRITER);
DPRINTF(("%s: %d.%d exiting.\n", __func__, p->p_pid, l->l_lid));
timers_free(p, TIMERS_ALL);
#if defined(__HAVE_RAS)
ras_purgeall();
#endif
/*
* Close open files, release open-file table and free signal
* actions. This may block!
*/
fd_free();
cwdfree(p->p_cwdi);
p->p_cwdi = NULL;
doexithooks(p);
sigactsfree(p->p_sigacts);
/*
* Write out accounting data.
*/
(void)acct_process(l);
#ifdef KTRACE
/*
* Release trace file.
*/
if (p->p_tracep != NULL) {
mutex_enter(&ktrace_lock);
ktrderef(p);
mutex_exit(&ktrace_lock);
}
#endif
p->p_xexit = exitcode;
p->p_xsig = signo;
/*
* If emulation has process exit hook, call it now.
* Set the exit status now so that the exit hook has
* an opportunity to tweak it (COMPAT_LINUX requires
* this for thread group emulation)
*/
if (p->p_emul->e_proc_exit)
(*p->p_emul->e_proc_exit)(p);
/*
* Free the VM resources we're still holding on to.
* We must do this from a valid thread because doing
* so may block. This frees vmspace, which we don't
* need anymore. The only remaining lwp is the one
* we run at this moment, nothing runs in userland
* anymore.
*/
ruspace(p); /* Update our vm resource use */
uvm_proc_exit(p);
/*
* Stop profiling.
*/
if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) {
mutex_spin_enter(&p->p_stmutex);
stopprofclock(p);
mutex_spin_exit(&p->p_stmutex);
}
/*
* If parent is waiting for us to exit or exec, PL_PPWAIT is set; we
* wake up the parent early to avoid deadlock. We can do this once
* the VM resources are released.
*/
mutex_enter(proc_lock);
if (p->p_lflag & PL_PPWAIT) {
lwp_t *lp;
l->l_lwpctl = NULL; /* was on loan from blocked parent */
p->p_lflag &= ~PL_PPWAIT;
lp = p->p_vforklwp;
p->p_vforklwp = NULL;
lp->l_vforkwaiting = false;
cv_broadcast(&lp->l_waitcv);
}
if (SESS_LEADER(p)) {
struct vnode *vprele = NULL, *vprevoke = NULL;
struct session *sp = p->p_session;
struct tty *tp;
if (sp->s_ttyvp) {
/*
* Controlling process.
* Signal foreground pgrp,
* drain controlling terminal
* and revoke access to controlling terminal.
*/
tp = sp->s_ttyp;
mutex_spin_enter(&tty_lock);
if (tp->t_session == sp) {
/* we can't guarantee the revoke will do this */
pgrp = tp->t_pgrp;
tp->t_pgrp = NULL;
tp->t_session = NULL;
mutex_spin_exit(&tty_lock);
if (pgrp != NULL) {
pgsignal(pgrp, SIGHUP, 1);
}
mutex_exit(proc_lock);
(void) ttywait(tp);
mutex_enter(proc_lock);
/* The tty could have been revoked. */
vprevoke = sp->s_ttyvp;
} else
mutex_spin_exit(&tty_lock);
vprele = sp->s_ttyvp;
sp->s_ttyvp = NULL;
/*
* s_ttyp is not zero'd; we use this to indicate
* that the session once had a controlling terminal.
* (for logging and informational purposes)
*/
}
sp->s_leader = NULL;
if (vprevoke != NULL || vprele != NULL) {
if (vprevoke != NULL) {
/* Releases proc_lock. */
proc_sessrele(sp);
VOP_REVOKE(vprevoke, REVOKEALL);
} else
mutex_exit(proc_lock);
if (vprele != NULL)
vrele(vprele);
mutex_enter(proc_lock);
}
}
fixjobc(p, p->p_pgrp, 0);
/* Release fstrans private data. */
fstrans_lwp_dtor(l);
/*
* Finalize the last LWP's specificdata, as well as the
* specificdata for the proc itself.
*/
lwp_finispecific(l);
proc_finispecific(p);
/*
* Notify interested parties of our demise.
*/
KNOTE(&p->p_klist, NOTE_EXIT);
SDT_PROBE(proc, kernel, , exit,
((p->p_sflag & PS_COREDUMP) ? CLD_DUMPED :
(p->p_xsig ? CLD_KILLED : CLD_EXITED)),
0,0,0,0);
/*
* Reset p_opptr pointer of all former children which got
* traced by another process and were reparented. We reset
* it to NULL here; the trace detach code then reparents
* the child to initproc. We only check allproc list, since
* eventual former children on zombproc list won't reference
* p_opptr anymore.
*/
if (__predict_false(p->p_slflag & PSL_CHTRACED)) {
struct proc *q;
PROCLIST_FOREACH(q, &allproc) {
if (q->p_opptr == p)
q->p_opptr = NULL;
}
PROCLIST_FOREACH(q, &zombproc) {
if (q->p_opptr == p)
q->p_opptr = NULL;
}
}
/*
* Give orphaned children to init(8).
*/
child = LIST_FIRST(&p->p_children);
wakeinit = (child != NULL);
for (; child != NULL; child = next_child) {
next_child = LIST_NEXT(child, p_sibling);
/*
* Traced processes are killed since their existence
* means someone is screwing up. Since we reset the
* trace flags, the logic in sys_wait4() would not be
* triggered to reparent the process to its
* original parent, so we must do this here.
*/
if (__predict_false(child->p_slflag & PSL_TRACED)) {
mutex_enter(p->p_lock);
child->p_slflag &=
~(PSL_TRACED|PSL_SYSCALL);
mutex_exit(p->p_lock);
if (child->p_opptr != child->p_pptr) {
struct proc *t = child->p_opptr;
proc_reparent(child, t ? t : initproc);
child->p_opptr = NULL;
} else
proc_reparent(child, initproc);
killproc(child, "orphaned traced process");
} else
proc_reparent(child, initproc);
}
/*
* Move proc from allproc to zombproc, it's now nearly ready to be
* collected by parent.
*/
LIST_REMOVE(l, l_list);
LIST_REMOVE(p, p_list);
LIST_INSERT_HEAD(&zombproc, p, p_list);
/*
* Mark the process as dead. We must do this before we signal
* the parent.
*/
p->p_stat = SDEAD;
/* Put in front of parent's sibling list for parent to collect it */
old_parent = p->p_pptr;
old_parent->p_nstopchild++;
if (LIST_FIRST(&old_parent->p_children) != p) {
/* Put child where it can be found quickly */
LIST_REMOVE(p, p_sibling);
LIST_INSERT_HEAD(&old_parent->p_children, p, p_sibling);
}
/*
* Notify parent that we're gone. If parent has the P_NOCLDWAIT
* flag set, notify init instead (and hope it will handle
* this situation).
*/
if (old_parent->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) {
proc_reparent(p, initproc);
wakeinit = 1;
/*
* If this was the last child of our parent, notify
* parent, so in case he was wait(2)ing, he will
* continue.
*/
if (LIST_FIRST(&old_parent->p_children) == NULL)
cv_broadcast(&old_parent->p_waitcv);
}
/* Reload parent pointer, since p may have been reparented above */
new_parent = p->p_pptr;
if (__predict_false(p->p_exitsig != 0)) {
exit_psignal(p, new_parent, &ksi);
kpsignal(new_parent, &ksi, NULL);
}
/* Calculate the final rusage info. */
calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime,
NULL, NULL);
if (wakeinit)
cv_broadcast(&initproc->p_waitcv);
callout_destroy(&l->l_timeout_ch);
/*
* Release any PCU resources before becoming a zombie.
*/
pcu_discard_all(l);
mutex_enter(p->p_lock);
/* Free the linux lwp id */
if ((l->l_pflag & LP_PIDLID) != 0 && l->l_lid != p->p_pid)
proc_free_pid(l->l_lid);
lwp_drainrefs(l);
lwp_lock(l);
l->l_prflag &= ~LPR_DETACHED;
l->l_stat = LSZOMB;
lwp_unlock(l);
KASSERT(curlwp == l);
KASSERT(p->p_nrlwps == 1);
KASSERT(p->p_nlwps == 1);
p->p_stat = SZOMB;
p->p_nrlwps--;
p->p_nzlwps++;
p->p_ndlwps = 0;
mutex_exit(p->p_lock);
/*
* Signal the parent to collect us, and drop the proclist lock.
* Drop debugger/procfs lock; no new references can be gained.
*/
cv_broadcast(&p->p_pptr->p_waitcv);
rw_exit(&p->p_reflock);
mutex_exit(proc_lock);
/* Verify that we hold no locks other than the kernel lock. */
LOCKDEBUG_BARRIER(&kernel_lock, 0);
/*
* NOTE: WE ARE NO LONGER ALLOWED TO SLEEP!
*/
/*
* Give machine-dependent code a chance to free any MD LWP
* resources. This must be done before uvm_lwp_exit(), in
* case these resources are in the PCB.
*/
cpu_lwp_free(l, 1);
pmap_deactivate(l);
/* This process no longer needs to hold the kernel lock. */
#ifdef notyet
/* XXXSMP hold in lwp_userret() */
KERNEL_UNLOCK_LAST(l);
#else
KERNEL_UNLOCK_ALL(l, NULL);
#endif
lwp_exit_switchaway(l);
}
void
exit_lwps(struct lwp *l)
{
proc_t *p = l->l_proc;
lwp_t *l2;
int nlocks;
KERNEL_UNLOCK_ALL(l, &nlocks);
retry:
KASSERT(mutex_owned(p->p_lock));
/*
* Interrupt LWPs in interruptable sleep, unsuspend suspended
* LWPs and then wait for everyone else to finish.
*/
LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
if (l2 == l)
continue;
lwp_lock(l2);
l2->l_flag |= LW_WEXIT;
if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) ||
l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) {
/* setrunnable() will release the lock. */
setrunnable(l2);
continue;
}
lwp_unlock(l2);
}
/*
* Wait for every LWP to exit. Note: LWPs can get suspended/slept
* behind us or there may even be new LWPs created. Therefore, a
* full retry is required on error.
*/
while (p->p_nlwps > 1) {
if (lwp_wait(l, 0, NULL, true)) {
goto retry;
}
}
KERNEL_LOCK(nlocks, l);
KASSERT(p->p_nlwps == 1);
}
int
do_sys_waitid(idtype_t idtype, id_t id, int *pid, int *status, int options,
struct wrusage *wru, siginfo_t *si)
{
proc_t *child;
int error;
if (wru != NULL)
memset(wru, 0, sizeof(*wru));
if (si != NULL)
memset(si, 0, sizeof(*si));
mutex_enter(proc_lock);
error = find_stopped_child(curproc, idtype, id, options, &child,
wru, si);
if (child == NULL) {
mutex_exit(proc_lock);
*pid = 0;
*status = 0;
return error;
}
*pid = child->p_pid;
if (child->p_stat == SZOMB) {
/* Child is exiting */
*status = P_WAITSTATUS(child);
/* proc_free() will release the proc_lock. */
if (options & WNOWAIT) {
mutex_exit(proc_lock);
} else {
proc_free(child, wru);
}
} else {
/* Don't mark SIGCONT if we are being stopped */
*status = (child->p_xsig == SIGCONT && child->p_stat != SSTOP) ?
W_CONTCODE() : W_STOPCODE(child->p_xsig);
mutex_exit(proc_lock);
}
return 0;
}
int
do_sys_wait(int *pid, int *status, int options, struct rusage *ru)
{
idtype_t idtype;
id_t id;
int ret;
struct wrusage wru;
/*
* Translate the special pid values into the (idtype, pid)
* pair for wait6. The WAIT_MYPGRP case is handled by
* find_stopped_child() on its own.
*/
if (*pid == WAIT_ANY) {
idtype = P_ALL;
id = 0;
} else if (*pid < 0) {
idtype = P_PGID;
id = (id_t)-*pid;
} else {
idtype = P_PID;
id = (id_t)*pid;
}
options |= WEXITED | WTRAPPED;
ret = do_sys_waitid(idtype, id, pid, status, options, ru ? &wru : NULL,
NULL);
if (ru)
*ru = wru.wru_self;
return ret;
}
int
sys___wait450(struct lwp *l, const struct sys___wait450_args *uap,
register_t *retval)
{
/* {
syscallarg(int) pid;
syscallarg(int *) status;
syscallarg(int) options;
syscallarg(struct rusage *) rusage;
} */
int error, status, pid = SCARG(uap, pid);
struct rusage ru;
error = do_sys_wait(&pid, &status, SCARG(uap, options),
SCARG(uap, rusage) != NULL ? &ru : NULL);
retval[0] = pid;
if (pid == 0) {
return error;
}
if (SCARG(uap, status)) {
error = copyout(&status, SCARG(uap, status), sizeof(status));
}
if (SCARG(uap, rusage) && error == 0) {
error = copyout(&ru, SCARG(uap, rusage), sizeof(ru));
}
return error;
}
int
sys_wait6(struct lwp *l, const struct sys_wait6_args *uap, register_t *retval)
{
/* {
syscallarg(idtype_t) idtype;
syscallarg(id_t) id;
syscallarg(int *) status;
syscallarg(int) options;
syscallarg(struct wrusage *) wru;
syscallarg(siginfo_t *) si;
} */
struct wrusage wru, *wrup;
siginfo_t si, *sip;
idtype_t idtype;
int pid;
id_t id;
int error, status;
idtype = SCARG(uap, idtype);
id = SCARG(uap, id);
if (SCARG(uap, wru) != NULL)
wrup = &wru;
else
wrup = NULL;
if (SCARG(uap, info) != NULL)
sip = &si;
else
sip = NULL;
/*
* We expect all callers of wait6() to know about WEXITED and
* WTRAPPED.
*/
error = do_sys_waitid(idtype, id, &pid, &status, SCARG(uap, options),
wrup, sip);
retval[0] = pid; /* tell userland who it was */
#if 0
/*
* should we copyout if there was no process, hence no useful data?
* We don't for an old sytle wait4() (etc) but I believe
* FreeBSD does for wait6(), so a tossup... Go with FreeBSD for now.
*/
if (pid == 0)
return error;
#endif
if (SCARG(uap, status) != NULL && error == 0)
error = copyout(&status, SCARG(uap, status), sizeof(status));
if (SCARG(uap, wru) != NULL && error == 0)
error = copyout(&wru, SCARG(uap, wru), sizeof(wru));
if (SCARG(uap, info) != NULL && error == 0)
error = copyout(&si, SCARG(uap, info), sizeof(si));
return error;
}
/*
* Find a process that matches the provided criteria, and fill siginfo
* and resources if found.
* Returns:
* -1: Not found, abort early
* 0: Not matched
* 1: Matched, there might be more matches
* 2: This is the only match
*/
static int
match_process(const struct proc *pp, struct proc **q, idtype_t idtype, id_t id,
int options, struct wrusage *wrusage, siginfo_t *siginfo)
{
struct rusage *rup;
struct proc *p = *q;
int rv = 1;
mutex_enter(p->p_lock);
switch (idtype) {
case P_ALL:
break;
case P_PID:
if (p->p_pid != (pid_t)id) {
mutex_exit(p->p_lock);
p = *q = proc_find_raw((pid_t)id);
if (p == NULL || p->p_stat == SIDL || p->p_pptr != pp) {
*q = NULL;
return -1;
}
mutex_enter(p->p_lock);
}
rv++;
break;
case P_PGID:
if (p->p_pgid != (pid_t)id)
goto out;
break;
case P_SID:
if (p->p_session->s_sid != (pid_t)id)
goto out;
break;
case P_UID:
if (kauth_cred_geteuid(p->p_cred) != (uid_t)id)
goto out;
break;
case P_GID:
if (kauth_cred_getegid(p->p_cred) != (gid_t)id)
goto out;
break;
case P_CID:
case P_PSETID:
case P_CPUID:
/* XXX: Implement me */
default:
out:
mutex_exit(p->p_lock);
return 0;
}
if ((options & WEXITED) == 0 && p->p_stat == SZOMB)
goto out;
if (siginfo != NULL) {
siginfo->si_errno = 0;
/*
* SUSv4 requires that the si_signo value is always
* SIGCHLD. Obey it despite the rfork(2) interface
* allows to request other signal for child exit
* notification.
*/
siginfo->si_signo = SIGCHLD;
/*
* This is still a rough estimate. We will fix the
* cases TRAPPED, STOPPED, and CONTINUED later.
*/
if (p->p_sflag & PS_COREDUMP) {
siginfo->si_code = CLD_DUMPED;
siginfo->si_status = p->p_xsig;
} else if (p->p_xsig) {
siginfo->si_code = CLD_KILLED;
siginfo->si_status = p->p_xsig;
} else {
siginfo->si_code = CLD_EXITED;
siginfo->si_status = p->p_xexit;
}
siginfo->si_pid = p->p_pid;
siginfo->si_uid = kauth_cred_geteuid(p->p_cred);
siginfo->si_utime = p->p_stats->p_ru.ru_utime.tv_sec;
siginfo->si_stime = p->p_stats->p_ru.ru_stime.tv_sec;
}
/*
* There should be no reason to limit resources usage info to
* exited processes only. A snapshot about any resources used
* by a stopped process may be exactly what is needed.
*/
if (wrusage != NULL) {
rup = &wrusage->wru_self;
*rup = p->p_stats->p_ru;
calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL);
rup = &wrusage->wru_children;
*rup = p->p_stats->p_cru;
calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL);
}
mutex_exit(p->p_lock);
return rv;
}
/*
* Determine if there are existing processes being debugged
* that used to be (and sometime later will be again) children
* of a specific parent (while matching wait criteria)
*/
static bool
debugged_child_exists(idtype_t idtype, id_t id, int options, siginfo_t *si,
const struct proc *parent)
{
struct proc *pp;
/*
* If we are searching for a specific pid, we can optimise a little
*/
if (idtype == P_PID) {
/*
* Check the specific process to see if its real parent is us
*/
pp = proc_find_raw((pid_t)id);
if (pp != NULL && pp->p_stat != SIDL && pp->p_opptr == parent) {
/*
* using P_ALL here avoids match_process() doing the
* same work that we just did, but incorrectly for
* this scenario.
*/
if (match_process(parent, &pp, P_ALL, id, options,
NULL, si))
return true;
}
return false;
}
/*
* For the hard cases, just look everywhere to see if some
* stolen (reparented) process is really our lost child.
* Then check if that process could satisfy the wait conditions.
*/
/*
* XXX inefficient, but hopefully fairly rare.
* XXX should really use a list of reparented processes.
*/
PROCLIST_FOREACH(pp, &allproc) {
if (pp->p_stat == SIDL) /* XXX impossible ?? */
continue;
if (pp->p_opptr == parent &&
match_process(parent, &pp, idtype, id, options, NULL, si))
return true;
}
PROCLIST_FOREACH(pp, &zombproc) {
if (pp->p_stat == SIDL) /* XXX impossible ?? */
continue;
if (pp->p_opptr == parent &&
match_process(parent, &pp, idtype, id, options, NULL, si))
return true;
}
return false;
}
/*
* Scan list of child processes for a child process that has stopped or
* exited. Used by sys_wait4 and 'compat' equivalents.
*
* Must be called with the proc_lock held, and may release while waiting.
*/
static int
find_stopped_child(struct proc *parent, idtype_t idtype, id_t id, int options,
struct proc **child_p, struct wrusage *wru, siginfo_t *si)
{
struct proc *child, *dead;
int error;
KASSERT(mutex_owned(proc_lock));
if (options & ~WALLOPTS) {
*child_p = NULL;
return EINVAL;
}
if ((options & WSELECTOPTS) == 0) {
/*
* We will be unable to find any matching processes,
* because there are no known events to look for.