ssh-keyscan.c revision 147005 
1/*
2 * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
3 *
4 * Modification and redistribution in source and binary forms is
5 * permitted provided that due credit is given to the author and the
6 * OpenBSD project by leaving this copyright notice intact.
7 */
8
9#include "includes.h"
10RCSID("$OpenBSD: ssh-keyscan.c,v 1.52 2005/03/01 15:47:14 jmc Exp $");
11
12#include "openbsd-compat/sys-queue.h"
13
14#include <openssl/bn.h>
15
16#include <setjmp.h>
17#include "xmalloc.h"
18#include "ssh.h"
19#include "ssh1.h"
20#include "key.h"
21#include "kex.h"
22#include "compat.h"
23#include "myproposal.h"
24#include "packet.h"
25#include "dispatch.h"
26#include "buffer.h"
27#include "bufaux.h"
28#include "log.h"
29#include "atomicio.h"
30#include "misc.h"
31#include "hostfile.h"
32
33/* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
34   Default value is AF_UNSPEC means both IPv4 and IPv6. */
35int IPv4or6 = AF_UNSPEC;
36
37int ssh_port = SSH_DEFAULT_PORT;
38
39#define KT_RSA1	1
40#define KT_DSA	2
41#define KT_RSA	4
42
43int get_keytypes = KT_RSA1;	/* Get only RSA1 keys by default */
44
45int hash_hosts = 0;		/* Hash hostname on output */
46
47#define MAXMAXFD 256
48
49/* The number of seconds after which to give up on a TCP connection */
50int timeout = 5;
51
52int maxfd;
53#define MAXCON (maxfd - 10)
54
55extern char *__progname;
56fd_set *read_wait;
57size_t read_wait_size;
58int ncon;
59int nonfatal_fatal = 0;
60jmp_buf kexjmp;
61Key *kexjmp_key;
62
63/*
64 * Keep a connection structure for each file descriptor.  The state
65 * associated with file descriptor n is held in fdcon[n].
66 */
67typedef struct Connection {
68	u_char c_status;	/* State of connection on this file desc. */
69#define CS_UNUSED 0		/* File descriptor unused */
70#define CS_CON 1		/* Waiting to connect/read greeting */
71#define CS_SIZE 2		/* Waiting to read initial packet size */
72#define CS_KEYS 3		/* Waiting to read public key packet */
73	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
74	int c_plen;		/* Packet length field for ssh packet */
75	int c_len;		/* Total bytes which must be read. */
76	int c_off;		/* Length of data read so far. */
77	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
78	char *c_namebase;	/* Address to free for c_name and c_namelist */
79	char *c_name;		/* Hostname of connection for errors */
80	char *c_namelist;	/* Pointer to other possible addresses */
81	char *c_output_name;	/* Hostname of connection for output */
82	char *c_data;		/* Data read from this fd */
83	Kex *c_kex;		/* The key-exchange struct for ssh2 */
84	struct timeval c_tv;	/* Time at which connection gets aborted */
85	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
86} con;
87
88TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
89con *fdcon;
90
91/*
92 *  This is just a wrapper around fgets() to make it usable.
93 */
94
95/* Stress-test.  Increase this later. */
96#define LINEBUF_SIZE 16
97
98typedef struct {
99	char *buf;
100	u_int size;
101	int lineno;
102	const char *filename;
103	FILE *stream;
104	void (*errfun) (const char *,...);
105} Linebuf;
106
107static Linebuf *
108Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
109{
110	Linebuf *lb;
111
112	if (!(lb = malloc(sizeof(*lb)))) {
113		if (errfun)
114			(*errfun) ("linebuf (%s): malloc failed\n",
115			    filename ? filename : "(stdin)");
116		return (NULL);
117	}
118	if (filename) {
119		lb->filename = filename;
120		if (!(lb->stream = fopen(filename, "r"))) {
121			xfree(lb);
122			if (errfun)
123				(*errfun) ("%s: %s\n", filename, strerror(errno));
124			return (NULL);
125		}
126	} else {
127		lb->filename = "(stdin)";
128		lb->stream = stdin;
129	}
130
131	if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
132		if (errfun)
133			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
134		xfree(lb);
135		return (NULL);
136	}
137	lb->errfun = errfun;
138	lb->lineno = 0;
139	return (lb);
140}
141
142static void
143Linebuf_free(Linebuf * lb)
144{
145	fclose(lb->stream);
146	xfree(lb->buf);
147	xfree(lb);
148}
149
150#if 0
151static void
152Linebuf_restart(Linebuf * lb)
153{
154	clearerr(lb->stream);
155	rewind(lb->stream);
156	lb->lineno = 0;
157}
158
159static int
160Linebuf_lineno(Linebuf * lb)
161{
162	return (lb->lineno);
163}
164#endif
165
166static char *
167Linebuf_getline(Linebuf * lb)
168{
169	int n = 0;
170	void *p;
171
172	lb->lineno++;
173	for (;;) {
174		/* Read a line */
175		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
176			if (ferror(lb->stream) && lb->errfun)
177				(*lb->errfun)("%s: %s\n", lb->filename,
178				    strerror(errno));
179			return (NULL);
180		}
181		n = strlen(lb->buf);
182
183		/* Return it or an error if it fits */
184		if (n > 0 && lb->buf[n - 1] == '\n') {
185			lb->buf[n - 1] = '\0';
186			return (lb->buf);
187		}
188		if (n != lb->size - 1) {
189			if (lb->errfun)
190				(*lb->errfun)("%s: skipping incomplete last line\n",
191				    lb->filename);
192			return (NULL);
193		}
194		/* Double the buffer if we need more space */
195		lb->size *= 2;
196		if ((p = realloc(lb->buf, lb->size)) == NULL) {
197			lb->size /= 2;
198			if (lb->errfun)
199				(*lb->errfun)("linebuf (%s): realloc failed\n",
200				    lb->filename);
201			return (NULL);
202		}
203		lb->buf = p;
204	}
205}
206
207static int
208fdlim_get(int hard)
209{
210#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
211	struct rlimit rlfd;
212
213	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
214		return (-1);
215	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
216		return SSH_SYSFDMAX;
217	else
218		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
219#else
220	return SSH_SYSFDMAX;
221#endif
222}
223
224static int
225fdlim_set(int lim)
226{
227#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
228	struct rlimit rlfd;
229#endif
230
231	if (lim <= 0)
232		return (-1);
233#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
234	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
235		return (-1);
236	rlfd.rlim_cur = lim;
237	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
238		return (-1);
239#elif defined (HAVE_SETDTABLESIZE)
240	setdtablesize(lim);
241#endif
242	return (0);
243}
244
245/*
246 * This is an strsep function that returns a null field for adjacent
247 * separators.  This is the same as the 4.4BSD strsep, but different from the
248 * one in the GNU libc.
249 */
250static char *
251xstrsep(char **str, const char *delim)
252{
253	char *s, *e;
254
255	if (!**str)
256		return (NULL);
257
258	s = *str;
259	e = s + strcspn(s, delim);
260
261	if (*e != '\0')
262		*e++ = '\0';
263	*str = e;
264
265	return (s);
266}
267
268/*
269 * Get the next non-null token (like GNU strsep).  Strsep() will return a
270 * null token for two adjacent separators, so we may have to loop.
271 */
272static char *
273strnnsep(char **stringp, char *delim)
274{
275	char *tok;
276
277	do {
278		tok = xstrsep(stringp, delim);
279	} while (tok && *tok == '\0');
280	return (tok);
281}
282
283static Key *
284keygrab_ssh1(con *c)
285{
286	static Key *rsa;
287	static Buffer msg;
288
289	if (rsa == NULL) {
290		buffer_init(&msg);
291		rsa = key_new(KEY_RSA1);
292	}
293	buffer_append(&msg, c->c_data, c->c_plen);
294	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
295	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
296		error("%s: invalid packet type", c->c_name);
297		buffer_clear(&msg);
298		return NULL;
299	}
300	buffer_consume(&msg, 8);		/* cookie */
301
302	/* server key */
303	(void) buffer_get_int(&msg);
304	buffer_get_bignum(&msg, rsa->rsa->e);
305	buffer_get_bignum(&msg, rsa->rsa->n);
306
307	/* host key */
308	(void) buffer_get_int(&msg);
309	buffer_get_bignum(&msg, rsa->rsa->e);
310	buffer_get_bignum(&msg, rsa->rsa->n);
311
312	buffer_clear(&msg);
313
314	return (rsa);
315}
316
317static int
318hostjump(Key *hostkey)
319{
320	kexjmp_key = hostkey;
321	longjmp(kexjmp, 1);
322}
323
324static int
325ssh2_capable(int remote_major, int remote_minor)
326{
327	switch (remote_major) {
328	case 1:
329		if (remote_minor == 99)
330			return 1;
331		break;
332	case 2:
333		return 1;
334	default:
335		break;
336	}
337	return 0;
338}
339
340static Key *
341keygrab_ssh2(con *c)
342{
343	int j;
344
345	packet_set_connection(c->c_fd, c->c_fd);
346	enable_compat20();
347	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
348	    "ssh-dss": "ssh-rsa";
349	c->c_kex = kex_setup(myproposal);
350	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
351	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
352	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
353	c->c_kex->verify_host_key = hostjump;
354
355	if (!(j = setjmp(kexjmp))) {
356		nonfatal_fatal = 1;
357		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
358		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
359		exit(1);
360	}
361	nonfatal_fatal = 0;
362	xfree(c->c_kex);
363	c->c_kex = NULL;
364	packet_close();
365
366	return j < 0? NULL : kexjmp_key;
367}
368
369static void
370keyprint(con *c, Key *key)
371{
372	char *host = c->c_output_name ? c->c_output_name : c->c_name;
373
374	if (!key)
375		return;
376	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
377		fatal("host_hash failed");
378
379	fprintf(stdout, "%s ", host);
380	key_write(key, stdout);
381	fputs("\n", stdout);
382}
383
384static int
385tcpconnect(char *host)
386{
387	struct addrinfo hints, *ai, *aitop;
388	char strport[NI_MAXSERV];
389	int gaierr, s = -1;
390
391	snprintf(strport, sizeof strport, "%d", ssh_port);
392	memset(&hints, 0, sizeof(hints));
393	hints.ai_family = IPv4or6;
394	hints.ai_socktype = SOCK_STREAM;
395	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
396		fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
397	for (ai = aitop; ai; ai = ai->ai_next) {
398		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
399		if (s < 0) {
400			error("socket: %s", strerror(errno));
401			continue;
402		}
403		if (set_nonblock(s) == -1)
404			fatal("%s: set_nonblock(%d)", __func__, s);
405		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
406		    errno != EINPROGRESS)
407			error("connect (`%s'): %s", host, strerror(errno));
408		else
409			break;
410		close(s);
411		s = -1;
412	}
413	freeaddrinfo(aitop);
414	return s;
415}
416
417static int
418conalloc(char *iname, char *oname, int keytype)
419{
420	char *namebase, *name, *namelist;
421	int s;
422
423	namebase = namelist = xstrdup(iname);
424
425	do {
426		name = xstrsep(&namelist, ",");
427		if (!name) {
428			xfree(namebase);
429			return (-1);
430		}
431	} while ((s = tcpconnect(name)) < 0);
432
433	if (s >= maxfd)
434		fatal("conalloc: fdno %d too high", s);
435	if (fdcon[s].c_status)
436		fatal("conalloc: attempt to reuse fdno %d", s);
437
438	fdcon[s].c_fd = s;
439	fdcon[s].c_status = CS_CON;
440	fdcon[s].c_namebase = namebase;
441	fdcon[s].c_name = name;
442	fdcon[s].c_namelist = namelist;
443	fdcon[s].c_output_name = xstrdup(oname);
444	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
445	fdcon[s].c_len = 4;
446	fdcon[s].c_off = 0;
447	fdcon[s].c_keytype = keytype;
448	gettimeofday(&fdcon[s].c_tv, NULL);
449	fdcon[s].c_tv.tv_sec += timeout;
450	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
451	FD_SET(s, read_wait);
452	ncon++;
453	return (s);
454}
455
456static void
457confree(int s)
458{
459	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
460		fatal("confree: attempt to free bad fdno %d", s);
461	close(s);
462	xfree(fdcon[s].c_namebase);
463	xfree(fdcon[s].c_output_name);
464	if (fdcon[s].c_status == CS_KEYS)
465		xfree(fdcon[s].c_data);
466	fdcon[s].c_status = CS_UNUSED;
467	fdcon[s].c_keytype = 0;
468	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
469	FD_CLR(s, read_wait);
470	ncon--;
471}
472
473static void
474contouch(int s)
475{
476	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
477	gettimeofday(&fdcon[s].c_tv, NULL);
478	fdcon[s].c_tv.tv_sec += timeout;
479	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
480}
481
482static int
483conrecycle(int s)
484{
485	con *c = &fdcon[s];
486	int ret;
487
488	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
489	confree(s);
490	return (ret);
491}
492
493static void
494congreet(int s)
495{
496	int remote_major = 0, remote_minor = 0, n = 0;
497	char buf[256], *cp;
498	char remote_version[sizeof buf];
499	size_t bufsiz;
500	con *c = &fdcon[s];
501
502	bufsiz = sizeof(buf);
503	cp = buf;
504	while (bufsiz-- && (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
505		if (*cp == '\r')
506			*cp = '\n';
507		cp++;
508	}
509	if (n < 0) {
510		if (errno != ECONNREFUSED)
511			error("read (%s): %s", c->c_name, strerror(errno));
512		conrecycle(s);
513		return;
514	}
515	if (n == 0) {
516		error("%s: Connection closed by remote host", c->c_name);
517		conrecycle(s);
518		return;
519	}
520	if (*cp != '\n' && *cp != '\r') {
521		error("%s: bad greeting", c->c_name);
522		confree(s);
523		return;
524	}
525	*cp = '\0';
526	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
527	    &remote_major, &remote_minor, remote_version) == 3)
528		compat_datafellows(remote_version);
529	else
530		datafellows = 0;
531	if (c->c_keytype != KT_RSA1) {
532		if (!ssh2_capable(remote_major, remote_minor)) {
533			debug("%s doesn't support ssh2", c->c_name);
534			confree(s);
535			return;
536		}
537	} else if (remote_major != 1) {
538		debug("%s doesn't support ssh1", c->c_name);
539		confree(s);
540		return;
541	}
542	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
543	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
544	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
545	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
546	if (atomicio(vwrite, s, buf, n) != n) {
547		error("write (%s): %s", c->c_name, strerror(errno));
548		confree(s);
549		return;
550	}
551	if (c->c_keytype != KT_RSA1) {
552		keyprint(c, keygrab_ssh2(c));
553		confree(s);
554		return;
555	}
556	c->c_status = CS_SIZE;
557	contouch(s);
558}
559
560static void
561conread(int s)
562{
563	con *c = &fdcon[s];
564	int n;
565
566	if (c->c_status == CS_CON) {
567		congreet(s);
568		return;
569	}
570	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
571	if (n < 0) {
572		error("read (%s): %s", c->c_name, strerror(errno));
573		confree(s);
574		return;
575	}
576	c->c_off += n;
577
578	if (c->c_off == c->c_len)
579		switch (c->c_status) {
580		case CS_SIZE:
581			c->c_plen = htonl(c->c_plen);
582			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
583			c->c_off = 0;
584			c->c_data = xmalloc(c->c_len);
585			c->c_status = CS_KEYS;
586			break;
587		case CS_KEYS:
588			keyprint(c, keygrab_ssh1(c));
589			confree(s);
590			return;
591			break;
592		default:
593			fatal("conread: invalid status %d", c->c_status);
594			break;
595		}
596
597	contouch(s);
598}
599
600static void
601conloop(void)
602{
603	struct timeval seltime, now;
604	fd_set *r, *e;
605	con *c;
606	int i;
607
608	gettimeofday(&now, NULL);
609	c = TAILQ_FIRST(&tq);
610
611	if (c && (c->c_tv.tv_sec > now.tv_sec ||
612	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
613		seltime = c->c_tv;
614		seltime.tv_sec -= now.tv_sec;
615		seltime.tv_usec -= now.tv_usec;
616		if (seltime.tv_usec < 0) {
617			seltime.tv_usec += 1000000;
618			seltime.tv_sec--;
619		}
620	} else
621		seltime.tv_sec = seltime.tv_usec = 0;
622
623	r = xmalloc(read_wait_size);
624	memcpy(r, read_wait, read_wait_size);
625	e = xmalloc(read_wait_size);
626	memcpy(e, read_wait, read_wait_size);
627
628	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
629	    (errno == EAGAIN || errno == EINTR))
630		;
631
632	for (i = 0; i < maxfd; i++) {
633		if (FD_ISSET(i, e)) {
634			error("%s: exception!", fdcon[i].c_name);
635			confree(i);
636		} else if (FD_ISSET(i, r))
637			conread(i);
638	}
639	xfree(r);
640	xfree(e);
641
642	c = TAILQ_FIRST(&tq);
643	while (c && (c->c_tv.tv_sec < now.tv_sec ||
644	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
645		int s = c->c_fd;
646
647		c = TAILQ_NEXT(c, c_link);
648		conrecycle(s);
649	}
650}
651
652static void
653do_host(char *host)
654{
655	char *name = strnnsep(&host, " \t\n");
656	int j;
657
658	if (name == NULL)
659		return;
660	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
661		if (get_keytypes & j) {
662			while (ncon >= MAXCON)
663				conloop();
664			conalloc(name, *host ? host : name, j);
665		}
666	}
667}
668
669void
670fatal(const char *fmt,...)
671{
672	va_list args;
673
674	va_start(args, fmt);
675	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
676	va_end(args);
677	if (nonfatal_fatal)
678		longjmp(kexjmp, -1);
679	else
680		exit(255);
681}
682
683static void
684usage(void)
685{
686	fprintf(stderr, "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
687	    "\t\t   [host | addrlist namelist] [...]\n",
688	    __progname);
689	exit(1);
690}
691
692int
693main(int argc, char **argv)
694{
695	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
696	int opt, fopt_count = 0;
697	char *tname;
698
699	extern int optind;
700	extern char *optarg;
701
702	__progname = ssh_get_progname(argv[0]);
703	init_rng();
704	seed_rng();
705	TAILQ_INIT(&tq);
706
707	if (argc <= 1)
708		usage();
709
710	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
711		switch (opt) {
712		case 'H':
713			hash_hosts = 1;
714			break;
715		case 'p':
716			ssh_port = a2port(optarg);
717			if (ssh_port == 0) {
718				fprintf(stderr, "Bad port '%s'\n", optarg);
719				exit(1);
720			}
721			break;
722		case 'T':
723			timeout = convtime(optarg);
724			if (timeout == -1 || timeout == 0) {
725				fprintf(stderr, "Bad timeout '%s'\n", optarg);
726				usage();
727			}
728			break;
729		case 'v':
730			if (!debug_flag) {
731				debug_flag = 1;
732				log_level = SYSLOG_LEVEL_DEBUG1;
733			}
734			else if (log_level < SYSLOG_LEVEL_DEBUG3)
735				log_level++;
736			else
737				fatal("Too high debugging level.");
738			break;
739		case 'f':
740			if (strcmp(optarg, "-") == 0)
741				optarg = NULL;
742			argv[fopt_count++] = optarg;
743			break;
744		case 't':
745			get_keytypes = 0;
746			tname = strtok(optarg, ",");
747			while (tname) {
748				int type = key_type_from_name(tname);
749				switch (type) {
750				case KEY_RSA1:
751					get_keytypes |= KT_RSA1;
752					break;
753				case KEY_DSA:
754					get_keytypes |= KT_DSA;
755					break;
756				case KEY_RSA:
757					get_keytypes |= KT_RSA;
758					break;
759				case KEY_UNSPEC:
760					fatal("unknown key type %s", tname);
761				}
762				tname = strtok(NULL, ",");
763			}
764			break;
765		case '4':
766			IPv4or6 = AF_INET;
767			break;
768		case '6':
769			IPv4or6 = AF_INET6;
770			break;
771		case '?':
772		default:
773			usage();
774		}
775	}
776	if (optind == argc && !fopt_count)
777		usage();
778
779	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
780
781	maxfd = fdlim_get(1);
782	if (maxfd < 0)
783		fatal("%s: fdlim_get: bad value", __progname);
784	if (maxfd > MAXMAXFD)
785		maxfd = MAXMAXFD;
786	if (MAXCON <= 0)
787		fatal("%s: not enough file descriptors", __progname);
788	if (maxfd > fdlim_get(0))
789		fdlim_set(maxfd);
790	fdcon = xmalloc(maxfd * sizeof(con));
791	memset(fdcon, 0, maxfd * sizeof(con));
792
793	read_wait_size = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
794	read_wait = xmalloc(read_wait_size);
795	memset(read_wait, 0, read_wait_size);
796
797	if (fopt_count) {
798		Linebuf *lb;
799		char *line;
800		int j;
801
802		for (j = 0; j < fopt_count; j++) {
803			lb = Linebuf_alloc(argv[j], error);
804			if (!lb)
805				continue;
806			while ((line = Linebuf_getline(lb)) != NULL)
807				do_host(line);
808			Linebuf_free(lb);
809		}
810	}
811
812	while (optind < argc)
813		do_host(argv[optind++]);
814
815	while (ncon > 0)
816		conloop();
817
818	return (0);
819}
820