xref: /plan9-contrib/sys/src/cmd/exportfs/exportfs.c (revision 2ec6491f4460014c01f3ea5c06b30b1a392b0bb2)
1 /*
2  * exportfs - Export a plan 9 name space across a network
3  */
4 #include <u.h>
5 #include <libc.h>
6 #include <auth.h>
7 #include <fcall.h>
8 #include <libsec.h>
9 #define Extern
10 #include "exportfs.h"
11 
12 #define QIDPATH	((1LL<<48)-1)
13 vlong newqid = 0;
14 
15 enum {
16 	Encnone,
17 	Encssl,
18 	Enctls,
19 };
20 
21 void (*fcalls[])(Fsrpc*) =
22 {
23 	[Tversion]	Xversion,
24 	[Tauth]	Xauth,
25 	[Tflush]	Xflush,
26 	[Tattach]	Xattach,
27 	[Twalk]		Xwalk,
28 	[Topen]		slave,
29 	[Tcreate]	Xcreate,
30 	[Tclunk]	Xclunk,
31 	[Tread]		slave,
32 	[Twrite]	slave,
33 	[Tremove]	Xremove,
34 	[Tstat]		Xstat,
35 	[Twstat]	Xwstat,
36 };
37 
38 /* accounting and debugging counters */
39 int	filecnt;
40 int	freecnt;
41 int	qidcnt;
42 int	qfreecnt;
43 int	ncollision;
44 
45 int	srvfd = -1;
46 int	nonone = 1;
47 char	*filterp;
48 char	*ealgs = "rc4_256 sha1";
49 char	*aanfilter = "/bin/aan";
50 int	encproto = Encnone;
51 int	readonly;
52 
53 static void mksecret(char *, uchar *);
54 static int localread9pmsg(int, void *, uint, void *);
55 static char *anstring  = "tcp!*!0";
56 
57 char *netdir = "", *local = "", *remote = "";
58 
59 void	filter(int, char *, char *);
60 
61 void
usage(void)62 usage(void)
63 {
64 	fprint(2, "usage: %s [-adnsR] [-f dbgfile] [-m msize] [-r root] "
65 		"[-S srvfile] [-e 'crypt hash'] [-P exclusion-file] "
66 		"[-A announce-string] [-B address]\n", argv0);
67 	fatal("usage");
68 }
69 
70 static void
noteconn(int fd)71 noteconn(int fd)
72 {
73 	NetConnInfo *nci;
74 
75 	nci = getnetconninfo(nil, fd);
76 	if(nci == nil)
77 		return;
78 	netdir = estrdup(nci->dir);
79 	local = estrdup(nci->lsys);
80 	remote = estrdup(nci->rsys);
81 	freenetconninfo(nci);
82 }
83 
84 void
main(int argc,char ** argv)85 main(int argc, char **argv)
86 {
87 	char buf[ERRMAX], ebuf[ERRMAX], initial[4], *ini, *srvfdfile;
88 	char *dbfile, *srv, *na, *nsfile, *keyspec;
89 	int doauth, n, fd;
90 	AuthInfo *ai;
91 	Fsrpc *r;
92 
93 	dbfile = "/tmp/exportdb";
94 	srv = nil;
95 	srvfd = -1;
96 	srvfdfile = nil;
97 	na = nil;
98 	nsfile = nil;
99 	keyspec = "";
100 	doauth = 0;
101 
102 	ai = nil;
103 	ARGBEGIN{
104 	case 'a':
105 		doauth = 1;
106 		break;
107 
108 	case 'd':
109 		dbg++;
110 		break;
111 
112 	case 'e':
113 		ealgs = EARGF(usage());
114 		if(*ealgs == 0 || strcmp(ealgs, "clear") == 0)
115 			ealgs = nil;
116 		break;
117 
118 	case 'f':
119 		dbfile = EARGF(usage());
120 		break;
121 
122 	case 'k':
123 		keyspec = EARGF(usage());
124 		break;
125 
126 	case 'm':
127 		messagesize = strtoul(EARGF(usage()), nil, 0);
128 		break;
129 
130 	case 'n':
131 		nonone = 0;
132 		break;
133 
134 	case 'r':
135 		srv = EARGF(usage());
136 		break;
137 
138 	case 's':
139 		srv = "/";
140 		break;
141 
142 	case 'A':
143 		anstring = EARGF(usage());
144 		break;
145 
146 	case 'B':
147 		na = EARGF(usage());
148 		break;
149 
150 	case 'F':
151 		/* accepted but ignored, for backwards compatibility */
152 		break;
153 
154 	case 'N':
155 		nsfile = EARGF(usage());
156 		break;
157 
158 	case 'P':
159 		patternfile = EARGF(usage());
160 		break;
161 
162 	case 'R':
163 		readonly = 1;
164 		break;
165 
166 	case 'S':
167 		if(srvfdfile != nil)
168 			usage();
169 		srvfdfile = EARGF(usage());
170 		break;
171 
172 	default:
173 		usage();
174 	}ARGEND
175 	USED(argc, argv);
176 
177 	if(na == nil && doauth){
178 		/*
179 		 * We use p9any so we don't have to visit this code again, with the
180 		 * cost that this code is incompatible with the old world, which
181 		 * requires p9sk2. (The two differ in who talks first, so compatibility
182 		 * is awkward.)
183 		 */
184 		ai = auth_proxy(0, auth_getkey, "proto=p9any role=server %s", keyspec);
185 		if(ai == nil)
186 			fatal("auth_proxy: %r");
187 		if(nonone && strcmp(ai->cuid, "none") == 0)
188 			fatal("exportfs by none disallowed");
189 		if(auth_chuid(ai, nsfile) < 0)
190 			fatal("auth_chuid: %r");
191 		putenv("service", "exportfs");
192 	}
193 
194 	if(srvfdfile != nil){
195 		if((srvfd = open(srvfdfile, ORDWR)) < 0)
196 			fatal("open %s: %r", srvfdfile);
197 	}
198 
199 	if(na != nil){
200 		if(srv == nil)
201 			fatal("-B requires -s");
202 
203 		local = "me";
204 		remote = na;
205 		if((fd = dial(netmkaddr(na, 0, "importfs"), 0, 0, 0)) < 0)
206 			fatal("can't dial %s: %r", na);
207 
208 		ai = auth_proxy(fd, auth_getkey, "proto=p9any role=client %s", keyspec);
209 		if(ai == nil)
210 			fatal("%r: %s", na);
211 
212 		dup(fd, 0);
213 		dup(fd, 1);
214 		close(fd);
215 	}
216 
217 	exclusions();
218 
219 	if(dbg) {
220 		n = create(dbfile, OWRITE|OTRUNC, 0666);
221 		dup(n, DFD);
222 		close(n);
223 	}
224 
225 	if(srvfd >= 0 && srv != nil){
226 		fprint(2, "exportfs: -S cannot be used with -r or -s\n");
227 		usage();
228 	}
229 
230 	DEBUG(DFD, "exportfs: started\n");
231 
232 	rfork(RFNOTEG|RFREND);
233 
234 	if(messagesize == 0){
235 		messagesize = iounit(0);
236 		if(messagesize == 0)
237 			messagesize = 16*1024+IOHDRSZ;
238 	}
239 	fhash = emallocz(sizeof(Fid*)*FHASHSIZE);
240 
241 	fmtinstall('F', fcallfmt);
242 
243 	/*
244 	 * Get tree to serve from network connection,
245 	 * check we can get there and ack the connection
246  	 */
247 	if(srvfd != -1) {
248 		/* do nothing */
249 	}
250 	else if(srv != nil) {
251 		if(chdir(srv) < 0) {
252 			errstr(ebuf, sizeof ebuf);
253 			fprint(0, "chdir(\"%s\"): %s\n", srv, ebuf);
254 			DEBUG(DFD, "chdir(\"%s\"): %s\n", srv, ebuf);
255 			exits(ebuf);
256 		}
257 		DEBUG(DFD, "invoked as server for %s", srv);
258 		strncpy(buf, srv, sizeof buf);
259 	}
260 	else {
261 		noteconn(0);
262 		buf[0] = 0;
263 		n = read(0, buf, sizeof(buf)-1);
264 		if(n < 0) {
265 			errstr(buf, sizeof buf);
266 			fprint(0, "read(0): %s\n", buf);
267 			DEBUG(DFD, "read(0): %s\n", buf);
268 			exits(buf);
269 		}
270 		buf[n] = 0;
271 		if(chdir(buf) < 0) {
272 			errstr(ebuf, sizeof ebuf);
273 			fprint(0, "chdir(%d:\"%s\"): %s\n", n, buf, ebuf);
274 			DEBUG(DFD, "chdir(%d:\"%s\"): %s\n", n, buf, ebuf);
275 			exits(ebuf);
276 		}
277 	}
278 
279 	DEBUG(DFD, "\niniting root\n");
280 	initroot();
281 
282 	DEBUG(DFD, "exportfs: %s\n", buf);
283 
284 	if(srv == nil && srvfd == -1 && write(0, "OK", 2) != 2)
285 		fatal("open ack write");
286 
287 	ini = initial;
288 	n = readn(0, initial, sizeof(initial));
289 	if(n == 0)
290 		fatal(nil);	/* port scan or spurious open/close on exported /srv file (unmount) */
291 	if(n < sizeof(initial))
292 		fatal("can't read initial string: %r");
293 
294 	if(memcmp(ini, "impo", 4) == 0) {
295 		char buf[128], *p, *args[3];
296 
297 		ini = nil;
298 		p = buf;
299 		for(;;){
300 			if((n = read(0, p, 1)) < 0)
301 				fatal("can't read impo arguments: %r");
302 			if(n == 0)
303 				fatal("connection closed while reading arguments");
304 			if(*p == '\n')
305 				*p = '\0';
306 			if(*p++ == '\0')
307 				break;
308 			if(p >= buf + sizeof(buf))
309 				fatal("import parameters too long");
310 		}
311 
312 		if(tokenize(buf, args, nelem(args)) != 2)
313 			fatal("impo arguments invalid: impo%s...", buf);
314 
315 		if(strcmp(args[0], "aan") == 0)
316 			filterp = aanfilter;
317 		else if(strcmp(args[0], "nofilter") != 0)
318 			fatal("import filter argument unsupported: %s", args[0]);
319 
320 		if(strcmp(args[1], "ssl") == 0)
321 			encproto = Encssl;
322 		else if(strcmp(args[1], "tls") == 0)
323 			encproto = Enctls;
324 		else if(strcmp(args[1], "clear") != 0)
325 			fatal("import encryption proto unsupported: %s", args[1]);
326 
327 		if(encproto == Enctls)
328 			fatal("%s: tls has not yet been implemented", argv[0]);
329 	}
330 
331 	if(encproto != Encnone && ealgs != nil && ai != nil) {
332 		uchar key[16], digest[SHA1dlen];
333 		char fromclientsecret[21];
334 		char fromserversecret[21];
335 		int i;
336 
337 		if(ai->nsecret < 8)
338 			fatal("secret too small for ssl");
339 		memmove(key+4, ai->secret, 8);
340 
341 		/* exchange random numbers */
342 		srand(truerand());
343 		for(i = 0; i < 4; i++)
344 			key[i+12] = rand();
345 
346 		if(ini != nil)
347 			fatal("Protocol botch: old import");
348 		if(readn(0, key, 4) != 4)
349 			fatal("can't read key part; %r");
350 
351 		if(write(0, key+12, 4) != 4)
352 			fatal("can't write key part; %r");
353 
354 		/* scramble into two secrets */
355 		sha1(key, sizeof(key), digest, nil);
356 		mksecret(fromclientsecret, digest);
357 		mksecret(fromserversecret, digest+10);
358 
359 		if(filterp != nil)
360 			filter(0, filterp, na);
361 
362 		switch(encproto) {
363 		case Encssl:
364 			fd = pushssl(0, ealgs, fromserversecret, fromclientsecret, nil);
365 			if(fd < 0)
366 				fatal("can't establish ssl connection: %r");
367 			if(fd != 0){
368 				dup(fd, 0);
369 				close(fd);
370 			}
371 			break;
372 		case Enctls:
373 		default:
374 			fatal("Unsupported encryption protocol");
375 		}
376 	}
377 	else if(filterp != nil) {
378 		if(ini != nil)
379 			fatal("Protocol botch: don't know how to deal with this");
380 		filter(0, filterp, na);
381 	}
382 	dup(0, 1);
383 
384 	if(ai != nil)
385 		auth_freeAI(ai);
386 
387 	/*
388 	 * Start serving file requests from the network
389 	 */
390 	for(;;) {
391 		r = getsbuf();
392 		while((n = localread9pmsg(0, r->buf, messagesize, ini)) == 0)
393 			;
394 		if(n < 0)
395 			fatal(nil);
396 		if(convM2S(r->buf, n, &r->work) == 0)
397 			fatal("convM2S format error");
398 
399 		DEBUG(DFD, "%F\n", &r->work);
400 		(fcalls[r->work.type])(r);
401 		ini = nil;
402 	}
403 }
404 
405 /*
406  * WARNING: Replace this with the original version as soon as all
407  * _old_ imports have been replaced with negotiating imports.  Also
408  * cpu relies on this (which needs to be fixed!) -- pb.
409  */
410 static int
localread9pmsg(int fd,void * abuf,uint n,void * ini)411 localread9pmsg(int fd, void *abuf, uint n, void *ini)
412 {
413 	int m, len;
414 	uchar *buf;
415 
416 	buf = abuf;
417 
418 	/* read count */
419 	if(ini != nil)
420 		memcpy(buf, ini, BIT32SZ);
421 	else {
422 		m = readn(fd, buf, BIT32SZ);
423 		if(m != BIT32SZ){
424 			if(m < 0)
425 				return -1;
426 			return 0;
427 		}
428 	}
429 
430 	len = GBIT32(buf);
431 	if(len <= BIT32SZ || len > n){
432 		werrstr("bad length in 9P2000 message header");
433 		return -1;
434 	}
435 	len -= BIT32SZ;
436 	m = readn(fd, buf+BIT32SZ, len);
437 	if(m < len)
438 		return 0;
439 	return BIT32SZ+m;
440 }
441 void
reply(Fcall * r,Fcall * t,char * err)442 reply(Fcall *r, Fcall *t, char *err)
443 {
444 	uchar *data;
445 	int n;
446 
447 	t->tag = r->tag;
448 	t->fid = r->fid;
449 	if(err != nil) {
450 		t->type = Rerror;
451 		t->ename = err;
452 	}
453 	else
454 		t->type = r->type + 1;
455 
456 	DEBUG(DFD, "\t%F\n", t);
457 
458 	data = malloc(messagesize);	/* not mallocz; no need to clear */
459 	if(data == nil)
460 		fatal(Enomem);
461 	n = convS2M(t, data, messagesize);
462 	if(write(0, data, n) != n){
463 		/* not fatal, might have got a note due to flush */
464 		fprint(2, "exportfs: short write in reply: %r\n");
465 	}
466 	free(data);
467 }
468 
469 Fid *
getfid(int nr)470 getfid(int nr)
471 {
472 	Fid *f;
473 
474 	for(f = fidhash(nr); f != nil; f = f->next)
475 		if(f->nr == nr)
476 			return f;
477 
478 	return nil;
479 }
480 
481 int
freefid(int nr)482 freefid(int nr)
483 {
484 	Fid *f, **l;
485 	char buf[128];
486 
487 	l = &fidhash(nr);
488 	for(f = *l; f != nil; f = f->next) {
489 		if(f->nr == nr) {
490 			if(f->mid) {
491 				snprint(buf, sizeof(buf), "/mnt/exportfs/%d", f->mid);
492 				unmount(0, buf);
493 				psmap[f->mid] = 0;
494 			}
495 			if(f->f != nil) {
496 				freefile(f->f);
497 				f->f = nil;
498 			}
499 			if(f->dir != nil){
500 				free(f->dir);
501 				f->dir = nil;
502 			}
503 			*l = f->next;
504 			f->next = fidfree;
505 			fidfree = f;
506 			return 1;
507 		}
508 		l = &f->next;
509 	}
510 
511 	return 0;
512 }
513 
514 Fid *
newfid(int nr)515 newfid(int nr)
516 {
517 	Fid *new, **l;
518 	int i;
519 
520 	l = &fidhash(nr);
521 	for(new = *l; new != nil; new = new->next)
522 		if(new->nr == nr)
523 			return nil;
524 
525 	if(fidfree == nil) {
526 		fidfree = emallocz(sizeof(Fid) * Fidchunk);
527 
528 		for(i = 0; i < Fidchunk-1; i++)
529 			fidfree[i].next = &fidfree[i+1];
530 
531 		fidfree[Fidchunk-1].next = nil;
532 	}
533 
534 	new = fidfree;
535 	fidfree = new->next;
536 
537 	memset(new, 0, sizeof(Fid));
538 	new->next = *l;
539 	*l = new;
540 	new->nr = nr;
541 	new->fid = -1;
542 	new->mid = 0;
543 
544 	return new;
545 }
546 
547 static struct {
548 	Lock;
549 	Fsrpc	*free;
550 
551 	/* statistics */
552 	int	nalloc;
553 	int	nfree;
554 }	sbufalloc;
555 
556 Fsrpc *
getsbuf(void)557 getsbuf(void)
558 {
559 	Fsrpc *w;
560 
561 	lock(&sbufalloc);
562 	w = sbufalloc.free;
563 	if(w != nil){
564 		sbufalloc.free = w->next;
565 		w->next = nil;
566 		sbufalloc.nfree--;
567 		unlock(&sbufalloc);
568 	} else {
569 		sbufalloc.nalloc++;
570 		unlock(&sbufalloc);
571 		w = emallocz(sizeof(*w) + messagesize);
572 	}
573 	w->flushtag = NOTAG;
574 	return w;
575 }
576 
577 void
putsbuf(Fsrpc * w)578 putsbuf(Fsrpc *w)
579 {
580 	w->flushtag = NOTAG;
581 	lock(&sbufalloc);
582 	w->next = sbufalloc.free;
583 	sbufalloc.free = w;
584 	sbufalloc.nfree++;
585 	unlock(&sbufalloc);
586 }
587 
588 void
freefile(File * f)589 freefile(File *f)
590 {
591 	File *parent, *child;
592 
593 	while(--f->ref == 0){
594 		freecnt++;
595 		DEBUG(DFD, "free %s\n", f->name);
596 		/* delete from parent */
597 		parent = f->parent;
598 		if(parent->child == f)
599 			parent->child = f->childlist;
600 		else{
601 			for(child = parent->child; child->childlist != f; child = child->childlist) {
602 				if(child->childlist == nil)
603 					fatal("bad child list");
604 			}
605 			child->childlist = f->childlist;
606 		}
607 		freeqid(f->qidt);
608 		free(f->name);
609 		free(f);
610 		f = parent;
611 	}
612 }
613 
614 File *
file(File * parent,char * name)615 file(File *parent, char *name)
616 {
617 	Dir *dir;
618 	char *path;
619 	File *f;
620 
621 	DEBUG(DFD, "\tfile: 0x%p %s name %s\n", parent, parent->name, name);
622 
623 	path = makepath(parent, name);
624 	if(patternfile != nil && excludefile(path)){
625 		free(path);
626 		return nil;
627 	}
628 	dir = dirstat(path);
629 	free(path);
630 	if(dir == nil)
631 		return nil;
632 
633 	for(f = parent->child; f != nil; f = f->childlist)
634 		if(strcmp(name, f->name) == 0)
635 			break;
636 
637 	if(f == nil){
638 		f = emallocz(sizeof(File));
639 		f->name = estrdup(name);
640 
641 		f->parent = parent;
642 		f->childlist = parent->child;
643 		parent->child = f;
644 		parent->ref++;
645 		f->ref = 0;
646 		filecnt++;
647 	}
648 	f->ref++;
649 	f->qid.type = dir->qid.type;
650 	f->qid.vers = dir->qid.vers;
651 	f->qidt = uniqueqid(dir);
652 	f->qid.path = f->qidt->uniqpath;
653 
654 	f->inval = 0;
655 
656 	free(dir);
657 
658 	return f;
659 }
660 
661 void
initroot(void)662 initroot(void)
663 {
664 	Dir *dir;
665 
666 	root = emallocz(sizeof(File));
667 	root->name = estrdup(".");
668 
669 	dir = dirstat(root->name);
670 	if(dir == nil)
671 		fatal("root stat");
672 
673 	root->ref = 1;
674 	root->qid.vers = dir->qid.vers;
675 	root->qidt = uniqueqid(dir);
676 	root->qid.path = root->qidt->uniqpath;
677 	root->qid.type = QTDIR;
678 	free(dir);
679 
680 	psmpt = emallocz(sizeof(File));
681 	psmpt->name = estrdup("/");
682 
683 	dir = dirstat(psmpt->name);
684 	if(dir == nil)
685 		return;
686 
687 	psmpt->ref = 1;
688 	psmpt->qid.vers = dir->qid.vers;
689 	psmpt->qidt = uniqueqid(dir);
690 	psmpt->qid.path = psmpt->qidt->uniqpath;
691 	free(dir);
692 
693 	psmpt = file(psmpt, "mnt");
694 	if(psmpt == nil)
695 		return;
696 	psmpt = file(psmpt, "exportfs");
697 }
698 
699 char*
makepath(File * p,char * name)700 makepath(File *p, char *name)
701 {
702 	int i, n;
703 	char *c, *s, *path, *seg[256];
704 
705 	seg[0] = name;
706 	n = strlen(name)+2;
707 	for(i = 1; i < 256 && p; i++, p = p->parent){
708 		seg[i] = p->name;
709 		n += strlen(p->name)+1;
710 	}
711 	path = emallocz(n);
712 	s = path;
713 
714 	while(i--) {
715 		for(c = seg[i]; *c; c++)
716 			*s++ = *c;
717 		*s++ = '/';
718 	}
719 	while(s[-1] == '/')
720 		s--;
721 	*s = '\0';
722 
723 	return path;
724 }
725 
726 int
qidhash(vlong path)727 qidhash(vlong path)
728 {
729 	int h, n;
730 
731 	h = 0;
732 	for(n=0; n<64; n+=Nqidbits){
733 		h ^= path;
734 		path >>= Nqidbits;
735 	}
736 	return h & (Nqidtab-1);
737 }
738 
739 void
freeqid(Qidtab * q)740 freeqid(Qidtab *q)
741 {
742 	ulong h;
743 	Qidtab *l;
744 
745 	if(--q->ref)
746 		return;
747 	qfreecnt++;
748 	h = qidhash(q->path);
749 	if(qidtab[h] == q)
750 		qidtab[h] = q->next;
751 	else{
752 		for(l=qidtab[h]; l->next!=q; l=l->next)
753 			if(l->next == nil)
754 				fatal("bad qid list");
755 		l->next = q->next;
756 	}
757 	free(q);
758 }
759 
760 Qidtab*
qidlookup(Dir * d)761 qidlookup(Dir *d)
762 {
763 	ulong h;
764 	Qidtab *q;
765 
766 	h = qidhash(d->qid.path);
767 	for(q=qidtab[h]; q!=nil; q=q->next)
768 		if(q->type==d->type && q->dev==d->dev && q->path==d->qid.path)
769 			return q;
770 	return nil;
771 }
772 
773 int
qidexists(vlong path)774 qidexists(vlong path)
775 {
776 	int h;
777 	Qidtab *q;
778 
779 	for(h=0; h<Nqidtab; h++)
780 		for(q=qidtab[h]; q!=nil; q=q->next)
781 			if(q->uniqpath == path)
782 				return 1;
783 	return 0;
784 }
785 
786 Qidtab*
uniqueqid(Dir * d)787 uniqueqid(Dir *d)
788 {
789 	ulong h;
790 	vlong path;
791 	Qidtab *q;
792 
793 	q = qidlookup(d);
794 	if(q != nil){
795 		q->ref++;
796 		return q;
797 	}
798 	path = d->qid.path;
799 	while(qidexists(path)){
800 		DEBUG(DFD, "collision on %s\n", d->name);
801 		/* collision: find a new one */
802 		ncollision++;
803 		path &= QIDPATH;
804 		++newqid;
805 		if(newqid >= (1<<16)){
806 			DEBUG(DFD, "collision wraparound\n");
807 			newqid = 1;
808 		}
809 		path |= newqid<<48;
810 		DEBUG(DFD, "assign qid %.16llux\n", path);
811 	}
812 	qidcnt++;
813 	q = emallocz(sizeof(Qidtab));
814 	q->ref = 1;
815 	q->type = d->type;
816 	q->dev = d->dev;
817 	q->path = d->qid.path;
818 	q->uniqpath = path;
819 	h = qidhash(d->qid.path);
820 	q->next = qidtab[h];
821 	qidtab[h] = q;
822 	return q;
823 }
824 
825 void
fatal(char * s,...)826 fatal(char *s, ...)
827 {
828 	char buf[ERRMAX];
829 	va_list arg;
830 	Proc *m;
831 
832 	if(s != nil) {
833 		va_start(arg, s);
834 		vsnprint(buf, ERRMAX, s, arg);
835 		va_end(arg);
836 	}
837 
838 	/* Clear away the slave children */
839 	for(m = Proclist; m != nil; m = m->next)
840 		postnote(PNPROC, m->pid, "kill");
841 
842 	if(s != nil) {
843 		DEBUG(DFD, "%s\n", buf);
844 		sysfatal("%s", buf);	/* caution: buf could contain '%' */
845 	} else
846 		exits(nil);
847 }
848 
849 void*
emallocz(uint n)850 emallocz(uint n)
851 {
852 	void *p;
853 
854 	p = mallocz(n, 1);
855 	if(p == nil)
856 		fatal(Enomem);
857 	setmalloctag(p, getcallerpc(&n));
858 	return p;
859 }
860 
861 char*
estrdup(char * s)862 estrdup(char *s)
863 {
864 	char *t;
865 
866 	t = strdup(s);
867 	if(t == nil)
868 		fatal(Enomem);
869 	setmalloctag(t, getcallerpc(&s));
870 	return t;
871 }
872 
873 void
filter(int fd,char * cmd,char * host)874 filter(int fd, char *cmd, char *host)
875 {
876 	char addr[128], buf[256], *s, *file, *argv[16];
877 	int lfd, p[2], len, argc;
878 
879 	if(host == nil){
880 		/* Get a free port and post it to the client. */
881 		if (announce(anstring, addr) < 0)
882 			fatal("filter: Cannot announce %s: %r", anstring);
883 
884 		snprint(buf, sizeof(buf), "%s/local", addr);
885 		if ((lfd = open(buf, OREAD)) < 0)
886 			fatal("filter: Cannot open %s: %r", buf);
887 		if ((len = read(lfd, buf, sizeof buf - 1)) < 0)
888 			fatal("filter: Cannot read %s: %r", buf);
889 		close(lfd);
890 		buf[len] = '\0';
891 		if ((s = strchr(buf, '\n')) != nil)
892 			len = s - buf;
893 		if (write(fd, buf, len) != len)
894 			fatal("filter: cannot write port; %r");
895 	} else {
896 		/* Read address string from connection */
897 		if ((len = read(fd, buf, sizeof buf - 1)) < 0)
898 			sysfatal("filter: cannot write port; %r");
899 		buf[len] = '\0';
900 
901 		if ((s = strrchr(buf, '!')) == nil)
902 			sysfatal("filter: illegally formatted port %s", buf);
903 		strecpy(addr, addr+sizeof(addr), netmkaddr(host, "tcp", s+1));
904 		strecpy(strrchr(addr, '!'), addr+sizeof(addr), s);
905 	}
906 
907 	DEBUG(DFD, "filter: %s\n", addr);
908 
909 	snprint(buf, sizeof(buf), "%s", cmd);
910 	argc = tokenize(buf, argv, nelem(argv)-3);
911 	if (argc == 0)
912 		sysfatal("filter: empty command");
913 
914 	if(host != nil)
915 		argv[argc++] = "-c";
916 	argv[argc++] = addr;
917 	argv[argc] = nil;
918 
919 	file = argv[0];
920 	if((s = strrchr(argv[0], '/')) != nil)
921 		argv[0] = s+1;
922 
923 	if(pipe(p) < 0)
924 		sysfatal("pipe: %r");
925 
926 	switch(rfork(RFNOWAIT|RFPROC|RFMEM|RFFDG|RFREND)) {
927 	case -1:
928 		fatal("filter: rfork; %r\n");
929 	case 0:
930 		close(fd);
931 		if (dup(p[0], 1) < 0)
932 			fatal("filter: Cannot dup to 1; %r");
933 		if (dup(p[0], 0) < 0)
934 			fatal("filter: Cannot dup to 0; %r");
935 		close(p[0]);
936 		close(p[1]);
937 		exec(file, argv);
938 		fatal("filter: exec; %r");
939 	default:
940 		dup(p[1], fd);
941 		close(p[0]);
942 		close(p[1]);
943 	}
944 }
945 
946 static void
mksecret(char * t,uchar * f)947 mksecret(char *t, uchar *f)
948 {
949 	sprint(t, "%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux",
950 		f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
951 }
952