1 #include "threadimpl.h"
2 
3 int	_threaddebuglevel;
4 
5 static	uint		threadnproc;
6 static	uint		threadnsysproc;
7 static	Lock		threadnproclock;
8 static	Ref		threadidref;
9 static	Proc		*threadmainproc;
10 
11 static	void		addproc(Proc*);
12 static	void		delproc(Proc*);
13 static	void		addthread(_Threadlist*, _Thread*);
14 static	void		delthread(_Threadlist*, _Thread*);
15 static	int		onlist(_Threadlist*, _Thread*);
16 static	void		addthreadinproc(Proc*, _Thread*);
17 static	void		delthreadinproc(Proc*, _Thread*);
18 static	void		contextswitch(Context *from, Context *to);
19 static	void		procscheduler(Proc*);
20 static	int		threadinfo(void*, char*);
21 
22 static void
23 _threaddebug(char *fmt, ...)
24 {
25 	va_list arg;
26 	char buf[128];
27 	_Thread *t;
28 	char *p;
29 	static int fd = -1;
30 
31 	if(_threaddebuglevel == 0)
32 		return;
33 
34 	if(fd < 0){
35 		p = strrchr(argv0, '/');
36 		if(p)
37 			p++;
38 		else
39 			p = argv0;
40 		snprint(buf, sizeof buf, "/tmp/%s.tlog", p);
41 		if((fd = create(buf, OWRITE, 0666)) < 0)
42 			fd = open("/dev/null", OWRITE);
43 		if(fd >= 0 && fd != 2){
44 			dup(fd, 2);
45 			close(fd);
46 			fd = 2;
47 		}
48 	}
49 
50 	va_start(arg, fmt);
51 	vsnprint(buf, sizeof buf, fmt, arg);
52 	va_end(arg);
53 	t = proc()->thread;
54 	if(t)
55 		fprint(fd, "%d.%d: %s\n", getpid(), t->id, buf);
56 	else
57 		fprint(fd, "%d._: %s\n", getpid(), buf);
58 }
59 
60 static _Thread*
61 getthreadnow(void)
62 {
63 	return proc()->thread;
64 }
65 _Thread	*(*threadnow)(void) = getthreadnow;
66 
67 static Proc*
68 procalloc(void)
69 {
70 	Proc *p;
71 
72 	p = malloc(sizeof *p);
73 	if(p == nil)
74 		sysfatal("procalloc malloc: %r");
75 	memset(p, 0, sizeof *p);
76 	addproc(p);
77 	lock(&threadnproclock);
78 	threadnproc++;
79 	unlock(&threadnproclock);
80 	return p;
81 }
82 
83 static void
84 threadstart(uint y, uint x)
85 {
86 	_Thread *t;
87 	ulong z;
88 
89 	z = (ulong)x << 16;	/* hide undefined 32-bit shift from 32-bit compilers */
90 	z <<= 16;
91 	z |= y;
92 	t = (_Thread*)z;
93 
94 /*print("threadstart %p\n", v); */
95 	t->startfn(t->startarg);
96 /*print("threadexits %p\n", v); */
97 	threadexits(nil);
98 /*print("not reacehd\n"); */
99 }
100 
101 static _Thread*
102 threadalloc(void (*fn)(void*), void *arg, uint stack)
103 {
104 	_Thread *t;
105 	sigset_t zero;
106 	uint x, y;
107 	ulong z;
108 
109 	/* allocate the task and stack together */
110 	t = malloc(sizeof *t+stack);
111 	if(t == nil)
112 		sysfatal("threadalloc malloc: %r");
113 	memset(t, 0, sizeof *t);
114 	t->stk = (uchar*)(t+1);
115 	t->stksize = stack;
116 	t->id = incref(&threadidref);
117 	t->startfn = fn;
118 	t->startarg = arg;
119 
120 	/* do a reasonable initialization */
121 	memset(&t->context.uc, 0, sizeof t->context.uc);
122 	sigemptyset(&zero);
123 	sigprocmask(SIG_BLOCK, &zero, &t->context.uc.uc_sigmask);
124 
125 	/* must initialize with current context */
126 	if(getcontext(&t->context.uc) < 0)
127 		sysfatal("threadalloc getcontext: %r");
128 
129 	/* call makecontext to do the real work. */
130 	/* leave a few words open on both ends */
131 	t->context.uc.uc_stack.ss_sp = t->stk+8;
132 	t->context.uc.uc_stack.ss_size = t->stksize-64;
133 #if defined(__sun__) && !defined(__MAKECONTEXT_V2_SOURCE)		/* sigh */
134 	/* can avoid this with __MAKECONTEXT_V2_SOURCE but only on SunOS 5.9 */
135 	t->context.uc.uc_stack.ss_sp = 
136 		(char*)t->context.uc.uc_stack.ss_sp
137 		+t->context.uc.uc_stack.ss_size;
138 #endif
139 	/*
140 	 * All this magic is because you have to pass makecontext a
141 	 * function that takes some number of word-sized variables,
142 	 * and on 64-bit machines pointers are bigger than words.
143 	 */
144 	z = (ulong)t;
145 	y = z;
146 	z >>= 16;	/* hide undefined 32-bit shift from 32-bit compilers */
147 	x = z>>16;
148 	makecontext(&t->context.uc, (void(*)(void))threadstart, 2, y, x);
149 
150 	return t;
151 }
152 
153 _Thread*
154 _threadcreate(Proc *p, void (*fn)(void*), void *arg, uint stack)
155 {
156 	_Thread *t;
157 
158 	t = threadalloc(fn, arg, stack);
159 	t->proc = p;
160 	addthreadinproc(p, t);
161 	p->nthread++;
162 	_threadready(t);
163 	return t;
164 }
165 
166 int
167 threadcreate(void (*fn)(void*), void *arg, uint stack)
168 {
169 	_Thread *t;
170 
171 	t = _threadcreate(proc(), fn, arg, stack);
172 	return t->id;
173 }
174 
175 int
176 proccreate(void (*fn)(void*), void *arg, uint stack)
177 {
178 	int id;
179 	_Thread *t;
180 	Proc *p;
181 
182 	p = procalloc();
183 	t = _threadcreate(p, fn, arg, stack);
184 	id = t->id;	/* t might be freed after _procstart */
185 	_procstart(p, procscheduler);
186 	return id;
187 }
188 
189 void
190 _threadswitch(void)
191 {
192 	Proc *p;
193 
194 	needstack(0);
195 	p = proc();
196 /*print("threadswtch %p\n", p); */
197 	contextswitch(&p->thread->context, &p->schedcontext);
198 }
199 
200 void
201 _threadready(_Thread *t)
202 {
203 	Proc *p;
204 
205 	p = t->proc;
206 	lock(&p->lock);
207 	p->runrend.l = &p->lock;
208 	addthread(&p->runqueue, t);
209 /*print("%d wake for job %d->%d\n", time(0), getpid(), p->osprocid); */
210 	if(p != proc())
211 		_procwakeupandunlock(&p->runrend);
212 	else
213 		unlock(&p->lock);
214 }
215 
216 int
217 threadidle(void)
218 {
219 	int n;
220 	Proc *p;
221 	
222 	p = proc();
223 	n = p->nswitch;
224 	lock(&p->lock);
225 	p->runrend.l = &p->lock;
226 	addthread(&p->idlequeue, p->thread);
227 	unlock(&p->lock);
228 	_threadswitch();
229 	return p->nswitch - n;
230 }
231 
232 int
233 threadyield(void)
234 {
235 	int n;
236 	Proc *p;
237 
238 	p = proc();
239 	n = p->nswitch;
240 	_threadready(p->thread);
241 	_threadswitch();
242 	return p->nswitch - n;
243 }
244 
245 void
246 threadexits(char *msg)
247 {
248 	Proc *p;
249 
250 	p = proc();
251 	if(msg == nil)
252 		msg = "";
253 	utfecpy(p->msg, p->msg+sizeof p->msg, msg);
254 	proc()->thread->exiting = 1;
255 	_threadswitch();
256 }
257 
258 void
259 threadpin(void)
260 {
261 	Proc *p;
262 
263 	p = proc();
264 	if(p->pinthread){
265 		fprint(2, "already pinning a thread - %p %p\n", p->pinthread, p->thread);
266 		assert(0);
267 	}
268 	p->pinthread = p->thread;
269 }
270 
271 void
272 threadunpin(void)
273 {
274 	Proc *p;
275 
276 	p = proc();
277 	if(p->pinthread != p->thread){
278 		fprint(2, "wrong pinthread - %p %p\n", p->pinthread, p->thread);
279 		assert(0);
280 	}
281 	p->pinthread = nil;
282 }
283 
284 static void
285 contextswitch(Context *from, Context *to)
286 {
287 	if(swapcontext(&from->uc, &to->uc) < 0){
288 		fprint(2, "swapcontext failed: %r\n");
289 		assert(0);
290 	}
291 }
292 
293 static void
294 procscheduler(Proc *p)
295 {
296 	_Thread *t;
297 
298 	setproc(p);
299 	_threaddebug("scheduler enter");
300 /*	print("s %p\n", p); */
301 	lock(&p->lock);
302 	for(;;){
303 		if((t = p->pinthread) != nil){
304 			while(!onlist(&p->runqueue, t)){
305 				p->runrend.l = &p->lock;
306 				_threaddebug("scheduler sleep (pin)");
307 				_procsleep(&p->runrend);
308 				_threaddebug("scheduler wake (pin)");
309 			}
310 		}else
311 		while((t = p->runqueue.head) == nil){
312 			if(p->nthread == 0)
313 				goto Out;
314 			if((t = p->idlequeue.head) != nil){
315 				/*
316 				 * Run all the idling threads once.
317 				 */
318 				while((t = p->idlequeue.head) != nil){
319 					delthread(&p->idlequeue, t);
320 					addthread(&p->runqueue, t);
321 				}
322 				continue;
323 			}
324 			p->runrend.l = &p->lock;
325 			_threaddebug("scheduler sleep");
326 			_procsleep(&p->runrend);
327 			_threaddebug("scheduler wake");
328 		}
329 		if(p->pinthread && p->pinthread != t)
330 			fprint(2, "p->pinthread %p t %p\n", p->pinthread, t);
331 		assert(p->pinthread == nil || p->pinthread == t);
332 		delthread(&p->runqueue, t);
333 		unlock(&p->lock);
334 		p->thread = t;
335 		p->nswitch++;
336 		_threaddebug("run %d (%s)", t->id, t->name);
337 		contextswitch(&p->schedcontext, &t->context);
338 /*print("back in scheduler\n"); */
339 		p->thread = nil;
340 		lock(&p->lock);
341 		if(t->exiting){
342 			delthreadinproc(p, t);
343 			p->nthread--;
344 /*print("nthread %d\n", p->nthread); */
345 			free(t);
346 		}
347 	}
348 
349 Out:
350 	_threaddebug("scheduler exit");
351 	if(p->mainproc){
352 		/*
353 		 * Stupid bug - on Linux 2.6 and maybe elsewhere,
354 		 * if the main thread exits then the others keep running
355 		 * but the process shows up as a zombie in ps and is not
356 		 * attachable with ptrace.  We'll just sit around pretending
357 		 * to be a system proc instead of exiting.
358 		 */
359 		_threaddaemonize();
360 		lock(&threadnproclock);
361 		if(++threadnsysproc == threadnproc)
362 			threadexitsall(p->msg);
363 		p->sysproc = 1;
364 		unlock(&threadnproclock);
365 		for(;;)
366 		 	sleep(1000);
367 	}
368 
369 	delproc(p);
370 	lock(&threadnproclock);
371 	if(p->sysproc)
372 		--threadnsysproc;
373 	if(--threadnproc == threadnsysproc)
374 		threadexitsall(p->msg);
375 	unlock(&threadnproclock);
376 	unlock(&p->lock);
377 	_threadsetproc(nil);
378 	free(p);
379 }
380 
381 void
382 _threadsetsysproc(void)
383 {
384 	lock(&threadnproclock);
385 	if(++threadnsysproc == threadnproc)
386 		threadexitsall(nil);
387 	unlock(&threadnproclock);
388 	proc()->sysproc = 1;
389 }
390 
391 void**
392 procdata(void)
393 {
394 	return &proc()->udata;
395 }
396 
397 void**
398 threaddata(void)
399 {
400 	return &proc()->thread->udata;
401 }
402 
403 extern Jmp *(*_notejmpbuf)(void);
404 static Jmp*
405 threadnotejmp(void)
406 {
407 	return &proc()->sigjmp;
408 }
409 
410 /*
411  * debugging
412  */
413 void
414 threadsetname(char *fmt, ...)
415 {
416 	va_list arg;
417 	_Thread *t;
418 
419 	t = proc()->thread;
420 	va_start(arg, fmt);
421 	vsnprint(t->name, sizeof t->name, fmt, arg);
422 	va_end(arg);
423 }
424 
425 char*
426 threadgetname(void)
427 {
428 	return proc()->thread->name;
429 }
430 
431 void
432 threadsetstate(char *fmt, ...)
433 {
434 	va_list arg;
435 	_Thread *t;
436 
437 	t = proc()->thread;
438 	va_start(arg, fmt);
439 	vsnprint(t->state, sizeof t->name, fmt, arg);
440 	va_end(arg);
441 }
442 
443 int
444 threadid(void)
445 {
446 	_Thread *t;
447 	
448 	t = proc()->thread;
449 	return t->id;
450 }
451 
452 void
453 needstack(int n)
454 {
455 	_Thread *t;
456 
457 	t = proc()->thread;
458 
459 	if((char*)&t <= (char*)t->stk
460 	|| (char*)&t - (char*)t->stk < 256+n){
461 		fprint(2, "thread stack overflow: &t=%p tstk=%p n=%d\n", &t, t->stk, 256+n);
462 		abort();
463 	}
464 }
465 
466 /*
467  * locking
468  */
469 static int
470 threadqlock(QLock *l, int block, ulong pc)
471 {
472 /*print("threadqlock %p\n", l); */
473 	lock(&l->l);
474 	if(l->owner == nil){
475 		l->owner = (*threadnow)();
476 /*print("qlock %p @%#x by %p\n", l, pc, l->owner); */
477 		unlock(&l->l);
478 		return 1;
479 	}
480 	if(!block){
481 		unlock(&l->l);
482 		return 0;
483 	}
484 /*print("qsleep %p @%#x by %p\n", l, pc, (*threadnow)()); */
485 	addthread(&l->waiting, (*threadnow)());
486 	unlock(&l->l);
487 
488 	_threadswitch();
489 
490 	if(l->owner != (*threadnow)()){
491 		fprint(2, "%s: qlock pc=0x%lux owner=%p self=%p oops\n",
492 			argv0, pc, l->owner, (*threadnow)());
493 		abort();
494 	}
495 /*print("qlock wakeup %p @%#x by %p\n", l, pc, (*threadnow)()); */
496 	return 1;
497 }
498 
499 static void
500 threadqunlock(QLock *l, ulong pc)
501 {
502 	_Thread *ready;
503 	
504 	lock(&l->l);
505 /*print("qlock unlock %p @%#x by %p (owner %p)\n", l, pc, (*threadnow)(), l->owner); */
506 	if(l->owner == 0){
507 		fprint(2, "%s: qunlock pc=0x%lux owner=%p self=%p oops\n",
508 			argv0, pc, l->owner, (*threadnow)());
509 		abort();
510 	}
511 	if((l->owner = ready = l->waiting.head) != nil)
512 		delthread(&l->waiting, l->owner);
513 	/*
514 	 * N.B. Cannot call _threadready() before unlocking l->l,
515 	 * because the thread we are readying might:
516 	 *	- be in another proc
517 	 *	- start running immediately
518 	 *	- and free l before we get a chance to run again
519 	 */
520 	unlock(&l->l);
521 	if(ready)
522 		_threadready(l->owner);
523 }
524 
525 static int
526 threadrlock(RWLock *l, int block, ulong pc)
527 {
528 	USED(pc);
529 
530 	lock(&l->l);
531 	if(l->writer == nil && l->wwaiting.head == nil){
532 		l->readers++;
533 		unlock(&l->l);
534 		return 1;
535 	}
536 	if(!block){
537 		unlock(&l->l);
538 		return 0;
539 	}
540 	addthread(&l->rwaiting, (*threadnow)());
541 	unlock(&l->l);
542 	_threadswitch();
543 	return 1;	
544 }
545 
546 static int
547 threadwlock(RWLock *l, int block, ulong pc)
548 {
549 	USED(pc);
550 
551 	lock(&l->l);
552 	if(l->writer == nil && l->readers == 0){
553 		l->writer = (*threadnow)();
554 		unlock(&l->l);
555 		return 1;
556 	}
557 	if(!block){
558 		unlock(&l->l);
559 		return 0;
560 	}
561 	addthread(&l->wwaiting, (*threadnow)());
562 	unlock(&l->l);
563 	_threadswitch();
564 	return 1;
565 }
566 
567 static void
568 threadrunlock(RWLock *l, ulong pc)
569 {
570 	_Thread *t;
571 
572 	USED(pc);
573 	t = nil;
574 	lock(&l->l);
575 	--l->readers;
576 	if(l->readers == 0 && (t = l->wwaiting.head) != nil){
577 		delthread(&l->wwaiting, t);
578 		l->writer = t;
579 	}
580 	unlock(&l->l);
581 	if(t)
582 		_threadready(t);
583 
584 }
585 
586 static void
587 threadwunlock(RWLock *l, ulong pc)
588 {
589 	_Thread *t;
590 
591 	USED(pc);
592 	lock(&l->l);
593 	l->writer = nil;
594 	assert(l->readers == 0);
595 	while((t = l->rwaiting.head) != nil){
596 		delthread(&l->rwaiting, t);
597 		l->readers++;
598 		_threadready(t);
599 	}
600 	t = nil;
601 	if(l->readers == 0 && (t = l->wwaiting.head) != nil){
602 		delthread(&l->wwaiting, t);
603 		l->writer = t;
604 	}
605 	unlock(&l->l);
606 	if(t)
607 		_threadready(t);
608 }
609 
610 /*
611  * sleep and wakeup
612  */
613 static void
614 threadrsleep(Rendez *r, ulong pc)
615 {
616 	addthread(&r->waiting, proc()->thread);
617 	qunlock(r->l);
618 	_threadswitch();
619 	qlock(r->l);
620 }
621 
622 static int
623 threadrwakeup(Rendez *r, int all, ulong pc)
624 {
625 	int i;
626 	_Thread *t;
627 
628 	for(i=0;; i++){
629 		if(i==1 && !all)
630 			break;
631 		if((t = r->waiting.head) == nil)
632 			break;
633 		delthread(&r->waiting, t);
634 		_threadready(t);	
635 	}
636 	return i;
637 }
638 
639 /*
640  * startup
641  */
642 
643 static int threadargc;
644 static char **threadargv;
645 int mainstacksize;
646 extern int _p9usepwlibrary;	/* getgrgid etc. smash the stack - tell _p9dir just say no */
647 static void
648 threadmainstart(void *v)
649 {
650 	USED(v);
651 
652 	/*
653 	 * N.B. This call to proc() is a program's first call (indirectly) to a
654 	 * pthreads function while executing on a non-pthreads-allocated
655 	 * stack.  If the pthreads implementation is using the stack pointer
656 	 * to locate the per-thread data, then this call will blow up.
657 	 * This means the pthread implementation is not suitable for
658 	 * running under libthread.  Time to write your own.  Sorry.
659 	 */
660 	_p9usepwlibrary = 0;
661 	threadmainproc = proc();
662 	threadmain(threadargc, threadargv);
663 }
664 
665 int
666 main(int argc, char **argv)
667 {
668 	Proc *p;
669 
670 	argv0 = argv[0];
671 
672 	if(getenv("NOLIBTHREADDAEMONIZE") == nil)
673 		_threadsetupdaemonize();
674 
675 	threadargc = argc;
676 	threadargv = argv;
677 
678 	/*
679 	 * Install locking routines into C library.
680 	 */
681 	_lock = _threadlock;
682 	_unlock = _threadunlock;
683 	_qlock = threadqlock;
684 	_qunlock = threadqunlock;
685 	_rlock = threadrlock;
686 	_runlock = threadrunlock;
687 	_wlock = threadwlock;
688 	_wunlock = threadwunlock;
689 	_rsleep = threadrsleep;
690 	_rwakeup = threadrwakeup;
691 	_notejmpbuf = threadnotejmp;
692 	_pin = threadpin;
693 	_unpin = threadunpin;
694 
695 	_pthreadinit();
696 	p = procalloc();
697 	p->mainproc = 1;
698 	_threadsetproc(p);
699 	if(mainstacksize == 0)
700 		mainstacksize = 256*1024;
701 	atnotify(threadinfo, 1);
702 	_threadcreate(p, threadmainstart, nil, mainstacksize);
703 	procscheduler(p);
704 	sysfatal("procscheduler returned in threadmain!");
705 	/* does not return */
706 	return 0;
707 }
708 
709 /*
710  * hooray for linked lists
711  */
712 static void
713 addthread(_Threadlist *l, _Thread *t)
714 {
715 	if(l->tail){
716 		l->tail->next = t;
717 		t->prev = l->tail;
718 	}else{
719 		l->head = t;
720 		t->prev = nil;
721 	}
722 	l->tail = t;
723 	t->next = nil;
724 }
725 
726 static void
727 delthread(_Threadlist *l, _Thread *t)
728 {
729 	if(t->prev)
730 		t->prev->next = t->next;
731 	else
732 		l->head = t->next;
733 	if(t->next)
734 		t->next->prev = t->prev;
735 	else
736 		l->tail = t->prev;
737 }
738 
739 /* inefficient but rarely used */
740 static int
741 onlist(_Threadlist *l, _Thread *t)
742 {
743 	_Thread *tt;
744 
745 	for(tt = l->head; tt; tt=tt->next)
746 		if(tt == t)
747 			return 1;
748 	return 0;
749 }
750 
751 static void
752 addthreadinproc(Proc *p, _Thread *t)
753 {
754 	_Threadlist *l;
755 
756 	l = &p->allthreads;
757 	if(l->tail){
758 		l->tail->allnext = t;
759 		t->allprev = l->tail;
760 	}else{
761 		l->head = t;
762 		t->allprev = nil;
763 	}
764 	l->tail = t;
765 	t->allnext = nil;
766 }
767 
768 static void
769 delthreadinproc(Proc *p, _Thread *t)
770 {
771 	_Threadlist *l;
772 
773 	l = &p->allthreads;
774 	if(t->allprev)
775 		t->allprev->allnext = t->allnext;
776 	else
777 		l->head = t->allnext;
778 	if(t->allnext)
779 		t->allnext->allprev = t->allprev;
780 	else
781 		l->tail = t->allprev;
782 }
783 
784 Proc *_threadprocs;
785 Lock _threadprocslock;
786 static Proc *_threadprocstail;
787 
788 static void
789 addproc(Proc *p)
790 {
791 	lock(&_threadprocslock);
792 	if(_threadprocstail){
793 		_threadprocstail->next = p;
794 		p->prev = _threadprocstail;
795 	}else{
796 		_threadprocs = p;
797 		p->prev = nil;
798 	}
799 	_threadprocstail = p;
800 	p->next = nil;
801 	unlock(&_threadprocslock);
802 }
803 
804 static void
805 delproc(Proc *p)
806 {
807 	lock(&_threadprocslock);
808 	if(p->prev)
809 		p->prev->next = p->next;
810 	else
811 		_threadprocs = p->next;
812 	if(p->next)
813 		p->next->prev = p->prev;
814 	else
815 		_threadprocstail = p->prev;
816 	unlock(&_threadprocslock);
817 }
818 
819 /* 
820  * notify - for now just use the usual mechanisms
821  */
822 void
823 threadnotify(int (*f)(void*, char*), int in)
824 {
825 	atnotify(f, in);
826 }
827 
828 static int
829 onrunqueue(Proc *p, _Thread *t)
830 {
831 	_Thread *tt;
832 
833 	for(tt=p->runqueue.head; tt; tt=tt->next)
834 		if(tt == t)
835 			return 1;
836 	return 0;
837 }
838 
839 /*
840  * print state - called from SIGINFO
841  */
842 static int
843 threadinfo(void *v, char *s)
844 {
845 	Proc *p;
846 	_Thread *t;
847 
848 	if(strcmp(s, "quit") != 0 && strcmp(s, "sys: status request") != 0)
849 		return 0;
850 
851 	for(p=_threadprocs; p; p=p->next){
852 		fprint(2, "proc %p %s%s\n", (void*)p->osprocid, p->msg,
853 			p->sysproc ? " (sysproc)": "");
854 		for(t=p->allthreads.head; t; t=t->allnext){
855 			fprint(2, "\tthread %d %s: %s %s\n", 
856 				t->id, 
857 				t == p->thread ? "Running" : 
858 				onrunqueue(p, t) ? "Ready" : "Sleeping",
859 				t->state, t->name);
860 		}
861 	}
862 	return 1;
863 }
864 
865