xref: /netbsd/libexec/telnetd/telnetd.c (revision bf9ec67e)
1 /*	$NetBSD: telnetd.c,v 1.32 2002/01/31 07:54:50 itojun Exp $	*/
2 
3 /*
4  * Copyright (C) 1997 and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1989, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. All advertising materials mentioning features or use of this software
45  *    must display the following acknowledgement:
46  *	This product includes software developed by the University of
47  *	California, Berkeley and its contributors.
48  * 4. Neither the name of the University nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  */
64 
65 #include <sys/cdefs.h>
66 #ifndef lint
67 __COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
68 	The Regents of the University of California.  All rights reserved.\n");
69 #if 0
70 static char sccsid[] = "@(#)telnetd.c	8.4 (Berkeley) 5/30/95";
71 #else
72 __RCSID("$NetBSD: telnetd.c,v 1.32 2002/01/31 07:54:50 itojun Exp $");
73 #endif
74 #endif /* not lint */
75 
76 #include "telnetd.h"
77 #include "pathnames.h"
78 
79 #include <arpa/inet.h>
80 
81 #include <err.h>
82 #include <termcap.h>
83 
84 #include <limits.h>
85 
86 #define P __P
87 
88 #if	defined(_SC_CRAY_SECURE_SYS) && !defined(SCM_SECURITY)
89 /*
90  * UNICOS 6.0/6.1 do not have SCM_SECURITY defined, so we can
91  * use it to tell us to turn off all the socket security code,
92  * since that is only used in UNICOS 7.0 and later.
93  */
94 # undef _SC_CRAY_SECURE_SYS
95 #endif
96 
97 #if	defined(_SC_CRAY_SECURE_SYS)
98 #include <sys/sysv.h>
99 #include <sys/secdev.h>
100 # ifdef SO_SEC_MULTI		/* 8.0 code */
101 #include <sys/secparm.h>
102 #include <sys/usrv.h>
103 # endif /* SO_SEC_MULTI */
104 int	secflag;
105 char	tty_dev[16];
106 struct	secdev dv;
107 struct	sysv sysv;
108 # ifdef SO_SEC_MULTI		/* 8.0 code */
109 struct	socksec ss;
110 # else /* SO_SEC_MULTI */	/* 7.0 code */
111 struct	socket_security ss;
112 # endif /* SO_SEC_MULTI */
113 #endif	/* _SC_CRAY_SECURE_SYS */
114 
115 #if	defined(KRB5)
116 #define	Authenticator	k5_Authenticator
117 #include <krb5.h>
118 #undef	Authenticator
119 #include <com_err.h>
120 #endif
121 
122 #if	defined(AUTHENTICATION)
123 int	auth_level = 0;
124 #endif
125 
126 #if	defined(AUTHENTICATION) || defined(ENCRYPTION)
127 #include <libtelnet/misc.h>
128 #endif
129 
130 #if	defined(SECURELOGIN)
131 int	require_secure_login = 0;
132 #endif
133 
134 extern	int utmp_len;
135 extern int require_hwpreauth;
136 #ifdef KRB5
137 extern krb5_context telnet_context;
138 #endif
139 int	registerd_host_only = 0;
140 
141 #ifdef	STREAMSPTY
142 # include <stropts.h>
143 # include <termio.h>
144 /* make sure we don't get the bsd version */
145 # include "/usr/include/sys/tty.h"
146 # include <sys/ptyvar.h>
147 
148 /*
149  * Because of the way ptyibuf is used with streams messages, we need
150  * ptyibuf+1 to be on a full-word boundary.  The following weirdness
151  * is simply to make that happen.
152  */
153 long	ptyibufbuf[BUFSIZ/sizeof(long)+1];
154 char	*ptyibuf = ((char *)&ptyibufbuf[1])-1;
155 char	*ptyip = ((char *)&ptyibufbuf[1])-1;
156 char	ptyibuf2[BUFSIZ*4];
157 unsigned char ctlbuf[BUFSIZ];
158 struct	strbuf strbufc, strbufd;
159 
160 int readstream();
161 
162 #else	/* ! STREAMPTY */
163 
164 /*
165  * I/O data buffers,
166  * pointers, and counters.
167  */
168 char	ptyibuf[BUFSIZ], *ptyip = ptyibuf;
169 char	ptyibuf2[BUFSIZ];
170 
171 #endif /* ! STREAMPTY */
172 
173 int	hostinfo = 1;			/* do we print login banner? */
174 
175 #ifdef	CRAY
176 extern int      newmap; /* nonzero if \n maps to ^M^J */
177 int	lowpty = 0, highpty;	/* low, high pty numbers */
178 #endif /* CRAY */
179 
180 int debug = 0;
181 int keepalive = 1;
182 char *gettyname = "default";
183 char *progname;
184 
185 int main __P((int, char *[]));
186 void usage __P((void));
187 int getterminaltype __P((char *));
188 int getent __P((char *, char *));
189 void doit __P((struct sockaddr *));
190 void _gettermname __P((void));
191 int terminaltypeok __P((char *));
192 char *getstr __P((const char *, char **));
193 
194 /*
195  * The string to pass to getopt().  We do it this way so
196  * that only the actual options that we support will be
197  * passed off to getopt().
198  */
199 char valid_opts[] = {
200 	'd', ':', 'g', ':', 'h', 'k', 'n', 'S', ':', 'u', ':', 'U',
201 	'4', '6',
202 #ifdef	AUTHENTICATION
203 	'a', ':', 'X', ':',
204 #endif
205 #ifdef BFTPDAEMON
206 	'B',
207 #endif
208 #ifdef	ENCRYPTION
209 	'e', ':',
210 #endif
211 #ifdef DIAGNOSTICS
212 	'D', ':',
213 #endif
214 #ifdef	LINEMODE
215 	'l',
216 #endif
217 #ifdef CRAY
218 	'r', ':',
219 #endif
220 #ifdef	SECURELOGIN
221 	's',
222 #endif
223 #ifdef	KRB5
224 	'R', ':', 'H',
225 #endif
226 	'\0'
227 };
228 
229 int family = AF_INET;
230 
231 int
232 main(argc, argv)
233 	int argc;
234 	char *argv[];
235 {
236 	struct sockaddr_storage from;
237 	int on = 1, fromlen;
238 	register int ch;
239 #if	defined(IPPROTO_IP) && defined(IP_TOS)
240 	int tos = -1;
241 #endif
242 
243 	pfrontp = pbackp = ptyobuf;
244 	netip = netibuf;
245 	nfrontp = nbackp = netobuf;
246 #ifdef	ENCRYPTION
247 	nclearto = 0;
248 #endif	/* ENCRYPTION */
249 
250 	progname = *argv;
251 
252 #ifdef CRAY
253 	/*
254 	 * Get number of pty's before trying to process options,
255 	 * which may include changing pty range.
256 	 */
257 	highpty = getnpty();
258 #endif /* CRAY */
259 
260 	while ((ch = getopt(argc, argv, valid_opts)) != -1) {
261 		switch (ch) {
262 
263 #ifdef	AUTHENTICATION
264 		case 'a':
265 			/*
266 			 * Check for required authentication level
267 			 */
268 			if (strcmp(optarg, "debug") == 0) {
269 				auth_debug_mode = 1;
270 			} else if (strcasecmp(optarg, "none") == 0) {
271 				auth_level = 0;
272 			} else if (strcasecmp(optarg, "other") == 0) {
273 				auth_level = AUTH_OTHER;
274 			} else if (strcasecmp(optarg, "user") == 0) {
275 				auth_level = AUTH_USER;
276 			} else if (strcasecmp(optarg, "valid") == 0) {
277 				auth_level = AUTH_VALID;
278 			} else if (strcasecmp(optarg, "off") == 0) {
279 				/*
280 				 * This hack turns off authentication
281 				 */
282 				auth_level = -1;
283 			} else {
284 				fprintf(stderr,
285 			    "telnetd: unknown authorization level for -a\n");
286 			}
287 			break;
288 #endif	/* AUTHENTICATION */
289 
290 #ifdef BFTPDAEMON
291 		case 'B':
292 			bftpd++;
293 			break;
294 #endif /* BFTPDAEMON */
295 
296 		case 'd':
297 			if (strcmp(optarg, "ebug") == 0) {
298 				debug++;
299 				break;
300 			}
301 			usage();
302 			/* NOTREACHED */
303 			break;
304 
305 #ifdef DIAGNOSTICS
306 		case 'D':
307 			/*
308 			 * Check for desired diagnostics capabilities.
309 			 */
310 			if (!strcmp(optarg, "report")) {
311 				diagnostic |= TD_REPORT|TD_OPTIONS;
312 			} else if (!strcmp(optarg, "exercise")) {
313 				diagnostic |= TD_EXERCISE;
314 			} else if (!strcmp(optarg, "netdata")) {
315 				diagnostic |= TD_NETDATA;
316 			} else if (!strcmp(optarg, "ptydata")) {
317 				diagnostic |= TD_PTYDATA;
318 			} else if (!strcmp(optarg, "options")) {
319 				diagnostic |= TD_OPTIONS;
320 			} else {
321 				usage();
322 				/* NOT REACHED */
323 			}
324 			break;
325 #endif /* DIAGNOSTICS */
326 
327 #ifdef	ENCRYPTION
328 		case 'e':
329 			if (strcmp(optarg, "debug") == 0) {
330 				encrypt_debug_mode = 1;
331 				break;
332 			}
333 			usage();
334 			/* NOTREACHED */
335 			break;
336 #endif	/* ENCRYPTION */
337 
338 		case 'g':
339 			gettyname = optarg;
340 			break;
341 
342 		case 'h':
343 			hostinfo = 0;
344 			break;
345 
346 #ifdef	KRB5
347 		case 'H':
348 		    {
349 			require_hwpreauth = 1;
350 			break;
351 		    }
352 #endif	/* KRB5 */
353 
354 
355 #ifdef	LINEMODE
356 		case 'l':
357 			alwayslinemode = 1;
358 			break;
359 #endif	/* LINEMODE */
360 
361 		case 'k':
362 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
363 			lmodetype = NO_AUTOKLUDGE;
364 #else
365 			/* ignore -k option if built without kludge linemode */
366 #endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
367 			break;
368 
369 		case 'n':
370 			keepalive = 0;
371 			break;
372 
373 #ifdef CRAY
374 		case 'r':
375 		    {
376 			char *strchr();
377 			char *c;
378 
379 			/*
380 			 * Allow the specification of alterations
381 			 * to the pty search range.  It is legal to
382 			 * specify only one, and not change the
383 			 * other from its default.
384 			 */
385 			c = strchr(optarg, '-');
386 			if (c) {
387 				*c++ = '\0';
388 				highpty = atoi(c);
389 			}
390 			if (*optarg != '\0')
391 				lowpty = atoi(optarg);
392 			if ((lowpty > highpty) || (lowpty < 0) ||
393 							(highpty > 32767)) {
394 				usage();
395 				/* NOT REACHED */
396 			}
397 			break;
398 		    }
399 #endif	/* CRAY */
400 
401 #ifdef	KRB5
402 		case 'R':
403 		    {
404 			krb5_error_code retval;
405 
406 			if (telnet_context == 0) {
407 				retval = krb5_init_context(&telnet_context);
408 				if (retval) {
409 					com_err("telnetd", retval,
410 					    "while initializing krb5");
411 					exit(1);
412 				}
413 			}
414 			krb5_set_default_realm(telnet_context, optarg);
415 			break;
416 		    }
417 #endif	/* KRB5 */
418 
419 #ifdef	SECURELOGIN
420 		case 's':
421 			/* Secure login required */
422 			require_secure_login = 1;
423 			break;
424 #endif	/* SECURELOGIN */
425 		case 'S':
426 #ifdef	HAS_GETTOS
427 			if ((tos = parsetos(optarg, "tcp")) < 0)
428 				fprintf(stderr, "%s%s%s\n",
429 					"telnetd: Bad TOS argument '", optarg,
430 					"'; will try to use default TOS");
431 #else
432 			fprintf(stderr, "%s%s\n", "TOS option unavailable; ",
433 						"-S flag not supported\n");
434 #endif
435 			break;
436 
437 		case 'u':
438 			utmp_len = atoi(optarg);
439 			break;
440 
441 		case 'U':
442 			registerd_host_only = 1;
443 			break;
444 
445 #ifdef	AUTHENTICATION
446 		case 'X':
447 			/*
448 			 * Check for invalid authentication types
449 			 */
450 			auth_disable_name(optarg);
451 			break;
452 #endif	/* AUTHENTICATION */
453 
454 		case '4':
455 			family = AF_INET;
456 			break;
457 
458 		case '6':
459 			family = AF_INET6;
460 			break;
461 
462 		default:
463 			fprintf(stderr, "telnetd: %c: unknown option\n", ch);
464 			/* FALLTHROUGH */
465 		case '?':
466 			usage();
467 			/* NOTREACHED */
468 		}
469 	}
470 
471 	argc -= optind;
472 	argv += optind;
473 
474 	if (debug) {
475 	    int s, ns, foo, error;
476 	    char *service = "telnet";
477 	    struct addrinfo hints, *res;
478 
479 	    if (argc > 1) {
480 		usage();
481 		/* NOT REACHED */
482 	    } else if (argc == 1)
483 		service = *argv;
484 
485 	    memset(&hints, 0, sizeof(hints));
486 	    hints.ai_flags = AI_PASSIVE;
487 	    hints.ai_family = family;
488 	    hints.ai_socktype = SOCK_STREAM;
489 	    hints.ai_protocol = 0;
490 	    error = getaddrinfo(NULL, service, &hints, &res);
491 
492 	    if (error) {
493 		fprintf(stderr, "tcp/%s: %s\n", service, gai_strerror(error));
494 		exit(1);
495 	    }
496 
497 	    s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
498 	    if (s < 0) {
499 		perror("telnetd: socket");
500 		exit(1);
501 	    }
502 	    (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
503 				(char *)&on, sizeof(on));
504 	    if (bind(s, res->ai_addr, res->ai_addrlen) < 0) {
505 		perror("bind");
506 		exit(1);
507 	    }
508 	    if (listen(s, 1) < 0) {
509 		perror("listen");
510 		exit(1);
511 	    }
512 	    foo = res->ai_addrlen;
513 	    ns = accept(s, res->ai_addr, &foo);
514 	    if (ns < 0) {
515 		perror("accept");
516 		exit(1);
517 	    }
518 	    (void) dup2(ns, 0);
519 	    (void) close(ns);
520 	    (void) close(s);
521 #ifdef convex
522 	} else if (argc == 1) {
523 		; /* VOID*/		/* Just ignore the host/port name */
524 #endif
525 	} else if (argc > 0) {
526 		usage();
527 		/* NOT REACHED */
528 	}
529 
530 #if	defined(_SC_CRAY_SECURE_SYS)
531 	secflag = sysconf(_SC_CRAY_SECURE_SYS);
532 
533 	/*
534 	 *	Get socket's security label
535 	 */
536 	if (secflag)  {
537 		int szss = sizeof(ss);
538 #ifdef SO_SEC_MULTI			/* 8.0 code */
539 		int sock_multi;
540 		int szi = sizeof(int);
541 #endif /* SO_SEC_MULTI */
542 
543 		memset((char *)&dv, 0, sizeof(dv));
544 
545 		if (getsysv(&sysv, sizeof(struct sysv)) != 0) {
546 			perror("getsysv");
547 			exit(1);
548 		}
549 
550 		/*
551 		 *	Get socket security label and set device values
552 		 *	   {security label to be set on ttyp device}
553 		 */
554 #ifdef SO_SEC_MULTI			/* 8.0 code */
555 		if ((getsockopt(0, SOL_SOCKET, SO_SECURITY,
556 			       (char *)&ss, &szss) < 0) ||
557 		    (getsockopt(0, SOL_SOCKET, SO_SEC_MULTI,
558 				(char *)&sock_multi, &szi) < 0)) {
559 			perror("getsockopt");
560 			exit(1);
561 		} else {
562 			dv.dv_actlvl = ss.ss_actlabel.lt_level;
563 			dv.dv_actcmp = ss.ss_actlabel.lt_compart;
564 			if (!sock_multi) {
565 				dv.dv_minlvl = dv.dv_maxlvl = dv.dv_actlvl;
566 				dv.dv_valcmp = dv.dv_actcmp;
567 			} else {
568 				dv.dv_minlvl = ss.ss_minlabel.lt_level;
569 				dv.dv_maxlvl = ss.ss_maxlabel.lt_level;
570 				dv.dv_valcmp = ss.ss_maxlabel.lt_compart;
571 			}
572 			dv.dv_devflg = 0;
573 		}
574 #else /* SO_SEC_MULTI */		/* 7.0 code */
575 		if (getsockopt(0, SOL_SOCKET, SO_SECURITY,
576 				(char *)&ss, &szss) >= 0) {
577 			dv.dv_actlvl = ss.ss_slevel;
578 			dv.dv_actcmp = ss.ss_compart;
579 			dv.dv_minlvl = ss.ss_minlvl;
580 			dv.dv_maxlvl = ss.ss_maxlvl;
581 			dv.dv_valcmp = ss.ss_maxcmp;
582 		}
583 #endif /* SO_SEC_MULTI */
584 	}
585 #endif	/* _SC_CRAY_SECURE_SYS */
586 
587 	openlog("telnetd", LOG_PID, LOG_DAEMON);
588 	fromlen = sizeof (from);
589 	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
590 		fprintf(stderr, "%s: ", progname);
591 		perror("getpeername");
592 		_exit(1);
593 	}
594 	if (keepalive &&
595 	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
596 			(char *)&on, sizeof (on)) < 0) {
597 		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
598 	}
599 
600 #if	defined(IPPROTO_IP) && defined(IP_TOS)
601 	if (((struct sockaddr *)&from)->sa_family == AF_INET) {
602 # if	defined(HAS_GETTOS)
603 		struct tosent *tp;
604 		if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
605 			tos = tp->t_tos;
606 # endif
607 		if (tos < 0)
608 			tos = 020;	/* Low Delay bit */
609 		if (tos
610 		   && (setsockopt(0, IPPROTO_IP, IP_TOS,
611 				  (char *)&tos, sizeof(tos)) < 0)
612 		   && (errno != ENOPROTOOPT) )
613 			syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
614 	}
615 #endif	/* defined(IPPROTO_IP) && defined(IP_TOS) */
616 
617 	net = 0;
618 	doit((struct sockaddr *)&from);
619 	/* NOTREACHED */
620 #ifdef __GNUC__
621 	exit(0);
622 #endif
623 }  /* end of main */
624 
625 	void
626 usage()
627 {
628 	fprintf(stderr, "Usage: telnetd");
629 #ifdef	AUTHENTICATION
630 	fprintf(stderr, " [-a (debug|other|user|valid|off|none)]\n\t");
631 #endif
632 #ifdef BFTPDAEMON
633 	fprintf(stderr, " [-B]");
634 #endif
635 	fprintf(stderr, " [-debug]");
636 #ifdef DIAGNOSTICS
637 	fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
638 #endif
639 #ifdef	ENCRYPTION
640 	fprintf(stderr, " [-edebug]");
641 #endif
642 	fprintf(stderr, " [-h]");
643 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
644 	fprintf(stderr, " [-k]");
645 #endif
646 #ifdef LINEMODE
647 	fprintf(stderr, " [-l]");
648 #endif
649 	fprintf(stderr, " [-n]");
650 #ifdef	CRAY
651 	fprintf(stderr, " [-r[lowpty]-[highpty]]");
652 #endif
653 	fprintf(stderr, "\n\t");
654 #ifdef	SECURELOGIN
655 	fprintf(stderr, " [-s]");
656 #endif
657 #ifdef	HAS_GETTOS
658 	fprintf(stderr, " [-S tos]");
659 #endif
660 #ifdef	AUTHENTICATION
661 	fprintf(stderr, " [-X auth-type]");
662 #endif
663 	fprintf(stderr, " [-u utmp_hostname_length] [-U]");
664 	fprintf(stderr, " [port]\n");
665 	exit(1);
666 }
667 
668 /*
669  * getterminaltype
670  *
671  *	Ask the other end to send along its terminal type and speed.
672  * Output is the variable terminaltype filled in.
673  */
674 static unsigned char ttytype_sbbuf[] = {
675 	IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
676 };
677 
678     int
679 getterminaltype(name)
680     char *name;
681 {
682     int retval = -1;
683 
684     settimer(baseline);
685 #if	defined(AUTHENTICATION)
686     /*
687      * Handle the Authentication option before we do anything else.
688      */
689     send_do(TELOPT_AUTHENTICATION, 1);
690     while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
691 	ttloop();
692     if (his_state_is_will(TELOPT_AUTHENTICATION)) {
693 	retval = auth_wait(name);
694     }
695 #endif
696 
697 #ifdef	ENCRYPTION
698     send_will(TELOPT_ENCRYPT, 1);
699 #endif	/* ENCRYPTION */
700     send_do(TELOPT_TTYPE, 1);
701     send_do(TELOPT_TSPEED, 1);
702     send_do(TELOPT_XDISPLOC, 1);
703     send_do(TELOPT_NEW_ENVIRON, 1);
704     send_do(TELOPT_OLD_ENVIRON, 1);
705     while (
706 #ifdef	ENCRYPTION
707 	   his_do_dont_is_changing(TELOPT_ENCRYPT) ||
708 #endif	/* ENCRYPTION */
709 	   his_will_wont_is_changing(TELOPT_TTYPE) ||
710 	   his_will_wont_is_changing(TELOPT_TSPEED) ||
711 	   his_will_wont_is_changing(TELOPT_XDISPLOC) ||
712 	   his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
713 	   his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
714 	ttloop();
715     }
716     if (his_state_is_will(TELOPT_TSPEED)) {
717 	static unsigned char sb[] =
718 			{ IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
719 
720 	output_datalen((const char *)sb, sizeof sb);
721 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
722     }
723 #ifdef	ENCRYPTION
724     /*
725      * Wait for the negotiation of what type of encryption we can
726      * send with.  If autoencrypt is not set, this will just return.
727      */
728     if (his_state_is_will(TELOPT_ENCRYPT)) {
729 	encrypt_wait();
730     }
731 #endif	/* ENCRYPTION */
732     if (his_state_is_will(TELOPT_XDISPLOC)) {
733 	static unsigned char sb[] =
734 			{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
735 
736 	output_datalen((const char *)sb, sizeof sb);
737 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
738     }
739     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
740 	static unsigned char sb[] =
741 			{ IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
742 
743 	output_datalen((const char *)sb, sizeof sb);
744 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
745     }
746     else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
747 	static unsigned char sb[] =
748 			{ IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
749 
750 	output_datalen((const char *)sb, sizeof sb);
751 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
752     }
753     if (his_state_is_will(TELOPT_TTYPE)) {
754 
755 	output_datalen((const char *)ttytype_sbbuf, sizeof ttytype_sbbuf);
756 	DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
757 					sizeof ttytype_sbbuf - 2););
758     }
759     if (his_state_is_will(TELOPT_TSPEED)) {
760 	while (sequenceIs(tspeedsubopt, baseline))
761 	    ttloop();
762     }
763     if (his_state_is_will(TELOPT_XDISPLOC)) {
764 	while (sequenceIs(xdisplocsubopt, baseline))
765 	    ttloop();
766     }
767     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
768 	while (sequenceIs(environsubopt, baseline))
769 	    ttloop();
770     }
771     if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
772 	while (sequenceIs(oenvironsubopt, baseline))
773 	    ttloop();
774     }
775     if (his_state_is_will(TELOPT_TTYPE)) {
776 	char first[256], last[256];
777 
778 	while (sequenceIs(ttypesubopt, baseline))
779 	    ttloop();
780 
781 	/*
782 	 * If the other side has already disabled the option, then
783 	 * we have to just go with what we (might) have already gotten.
784 	 */
785 	if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
786 	    (void) strncpy(first, terminaltype, sizeof(first) - 1);
787 	    first[sizeof(first) - 1] = '\0';
788 	    for(;;) {
789 		/*
790 		 * Save the unknown name, and request the next name.
791 		 */
792 		(void) strncpy(last, terminaltype, sizeof(last) - 1);
793 		last[sizeof(last) - 1] = '\0';
794 		_gettermname();
795 		if (terminaltypeok(terminaltype))
796 		    break;
797 		if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
798 		    his_state_is_wont(TELOPT_TTYPE)) {
799 		    /*
800 		     * We've hit the end.  If this is the same as
801 		     * the first name, just go with it.
802 		     */
803 		    if (strncmp(first, terminaltype, sizeof(first)) == 0)
804 			break;
805 		    /*
806 		     * Get the terminal name one more time, so that
807 		     * RFC1091 compliant telnets will cycle back to
808 		     * the start of the list.
809 		     */
810 		     _gettermname();
811 		    if (strncmp(first, terminaltype, sizeof(first)) != 0) {
812 			(void) strncpy(terminaltype, first, sizeof(first) - 1);
813 			terminaltype[sizeof(terminaltype) - 1] = '\0';
814 		    }
815 		    break;
816 		}
817 	    }
818 	}
819     }
820     return(retval);
821 }  /* end of getterminaltype */
822 
823     void
824 _gettermname()
825 {
826     /*
827      * If the client turned off the option,
828      * we can't send another request, so we
829      * just return.
830      */
831     if (his_state_is_wont(TELOPT_TTYPE))
832 	return;
833     settimer(baseline);
834     output_datalen((const char *)ttytype_sbbuf, sizeof ttytype_sbbuf);
835     DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
836 					sizeof ttytype_sbbuf - 2););
837     while (sequenceIs(ttypesubopt, baseline))
838 	ttloop();
839 }
840 
841     int
842 terminaltypeok(s)
843     char *s;
844 {
845     char buf[1024];
846 
847     if (terminaltype == NULL)
848 	return(1);
849 
850     /*
851      * tgetent() will return 1 if the type is known, and
852      * 0 if it is not known.  If it returns -1, it couldn't
853      * open the database.  But if we can't open the database,
854      * it won't help to say we failed, because we won't be
855      * able to verify anything else.  So, we treat -1 like 1.
856      */
857     if (tgetent(buf, s) == 0)
858 	return(0);
859     return(1);
860 }
861 
862 #ifndef	MAXHOSTNAMELEN
863 #define	MAXHOSTNAMELEN 64
864 #endif	/* MAXHOSTNAMELEN */
865 
866 char *hostname;
867 char host_name[MAXHOSTNAMELEN + 1];
868 char remote_host_name[MAXHOSTNAMELEN + 1];
869 
870 #ifndef	convex
871 extern void telnet P((int, int));
872 #else
873 extern void telnet P((int, int, char *));
874 #endif
875 
876 /*
877  * Get a pty, scan input lines.
878  */
879 void
880 doit(who)
881 	struct sockaddr *who;
882 {
883 	char *host;
884 	int error;
885 	int level;
886 	int ptynum;
887 	char user_name[256];
888 
889 	/*
890 	 * Find an available pty to use.
891 	 */
892 #ifndef	convex
893 	pty = getpty(&ptynum);
894 	if (pty < 0)
895 		fatal(net, "All network ports in use");
896 #else
897 	for (;;) {
898 		char *lp;
899 
900 		if ((lp = getpty()) == NULL)
901 			fatal(net, "Out of ptys");
902 
903 		if ((pty = open(lp, 2)) >= 0) {
904 			(void)strlcpy(line, lp, sizeof(NULL16STR));
905 			line[5] = 't';
906 			break;
907 		}
908 	}
909 #endif
910 
911 #if	defined(_SC_CRAY_SECURE_SYS)
912 	/*
913 	 *	set ttyp line security label
914 	 */
915 	if (secflag) {
916 		char slave_dev[16];
917 
918 		sprintf(tty_dev, "/dev/pty/%03d", ptynum);
919 		if (setdevs(tty_dev, &dv) < 0)
920 		 	fatal(net, "cannot set pty security");
921 		sprintf(slave_dev, "/dev/ttyp%03d", ptynum);
922 		if (setdevs(slave_dev, &dv) < 0)
923 		 	fatal(net, "cannot set tty security");
924 	}
925 #endif	/* _SC_CRAY_SECURE_SYS */
926 
927 	/* get name of connected client */
928 	error = getnameinfo(who, who->sa_len, remote_host_name,
929 	    sizeof(remote_host_name), NULL, 0, 0);
930 
931 	if (!error && strlen(remote_host_name) > utmp_len)
932 		error = getnameinfo(who, who->sa_len, remote_host_name,
933 		    sizeof(remote_host_name), NULL, 0, NI_NUMERICHOST);
934 
935 	if (error) {
936 		fatal(net, "Couldn't resolve your address into a host name.\r\n\
937 	 Please contact your net administrator");
938 #ifdef __GNUC__
939 		host = NULL;	/* XXX gcc */
940 #endif
941 	}
942 
943 	remote_host_name[sizeof(remote_host_name)-1] = 0;
944 	host = remote_host_name;
945 
946 	(void)gethostname(host_name, sizeof (host_name));
947 	host_name[sizeof(host_name) - 1] = '\0';
948 	hostname = host_name;
949 
950 #if	defined(AUTHENTICATION) || defined(ENCRYPTION)
951 	auth_encrypt_init(hostname, host, "TELNETD", 1);
952 #endif
953 
954 	init_env();
955 	/*
956 	 * get terminal type.
957 	 */
958 	*user_name = 0;
959 	level = getterminaltype(user_name);
960 	setenv("TERM", terminaltype ? terminaltype : "network", 1);
961 
962 	/*
963 	 * Start up the login process on the slave side of the terminal
964 	 */
965 #ifndef	convex
966 	startslave(host, level, user_name);
967 
968 #if	defined(_SC_CRAY_SECURE_SYS)
969 	if (secflag) {
970 		if (setulvl(dv.dv_actlvl) < 0)
971 			fatal(net,"cannot setulvl()");
972 		if (setucmp(dv.dv_actcmp) < 0)
973 			fatal(net, "cannot setucmp()");
974 	}
975 #endif	/* _SC_CRAY_SECURE_SYS */
976 
977 	telnet(net, pty);  /* begin server processing */
978 #else
979 	telnet(net, pty, host);
980 #endif
981 	/*NOTREACHED*/
982 }  /* end of doit */
983 
984 
985 /*
986  * Main loop.  Select from pty and network, and
987  * hand data to telnet receiver finite state machine.
988  */
989 	void
990 #ifndef	convex
991 telnet(f, p)
992 #else
993 telnet(f, p, host)
994 #endif
995 	int f, p;
996 #ifdef convex
997 	char *host;
998 #endif
999 {
1000 	int on = 1;
1001 #define	TABBUFSIZ	512
1002 	char	defent[TABBUFSIZ];
1003 	char	defstrs[TABBUFSIZ];
1004 #undef	TABBUFSIZ
1005 	char *HE, *HN, *IM, *IF, *ptyibuf2ptr;
1006 	int nfd;
1007 
1008 	/*
1009 	 * Initialize the slc mapping table.
1010 	 */
1011 	get_slc_defaults();
1012 
1013 	/*
1014 	 * Do some tests where it is desireable to wait for a response.
1015 	 * Rather than doing them slowly, one at a time, do them all
1016 	 * at once.
1017 	 */
1018 	if (my_state_is_wont(TELOPT_SGA))
1019 		send_will(TELOPT_SGA, 1);
1020 	/*
1021 	 * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
1022 	 * because 4.2 clients are unable to deal with TCP urgent data.
1023 	 *
1024 	 * To find out, we send out a "DO ECHO".  If the remote system
1025 	 * answers "WILL ECHO" it is probably a 4.2 client, and we note
1026 	 * that fact ("WILL ECHO" ==> that the client will echo what
1027 	 * WE, the server, sends it; it does NOT mean that the client will
1028 	 * echo the terminal input).
1029 	 */
1030 	send_do(TELOPT_ECHO, 1);
1031 
1032 #ifdef	LINEMODE
1033 	if (his_state_is_wont(TELOPT_LINEMODE)) {
1034 		/* Query the peer for linemode support by trying to negotiate
1035 		 * the linemode option.
1036 		 */
1037 		linemode = 0;
1038 		editmode = 0;
1039 		send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
1040 	}
1041 #endif	/* LINEMODE */
1042 
1043 	/*
1044 	 * Send along a couple of other options that we wish to negotiate.
1045 	 */
1046 	send_do(TELOPT_NAWS, 1);
1047 	send_will(TELOPT_STATUS, 1);
1048 	flowmode = 1;		/* default flow control state */
1049 	restartany = -1;	/* uninitialized... */
1050 	send_do(TELOPT_LFLOW, 1);
1051 
1052 	/*
1053 	 * Spin, waiting for a response from the DO ECHO.  However,
1054 	 * some REALLY DUMB telnets out there might not respond
1055 	 * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
1056 	 * telnets so far seem to respond with WONT for a DO that
1057 	 * they don't understand...) because by the time we get the
1058 	 * response, it will already have processed the DO ECHO.
1059 	 * Kludge upon kludge.
1060 	 */
1061 	while (his_will_wont_is_changing(TELOPT_NAWS))
1062 		ttloop();
1063 
1064 	/*
1065 	 * But...
1066 	 * The client might have sent a WILL NAWS as part of its
1067 	 * startup code; if so, we'll be here before we get the
1068 	 * response to the DO ECHO.  We'll make the assumption
1069 	 * that any implementation that understands about NAWS
1070 	 * is a modern enough implementation that it will respond
1071 	 * to our DO ECHO request; hence we'll do another spin
1072 	 * waiting for the ECHO option to settle down, which is
1073 	 * what we wanted to do in the first place...
1074 	 */
1075 	if (his_want_state_is_will(TELOPT_ECHO) &&
1076 	    his_state_is_will(TELOPT_NAWS)) {
1077 		while (his_will_wont_is_changing(TELOPT_ECHO))
1078 			ttloop();
1079 	}
1080 	/*
1081 	 * On the off chance that the telnet client is broken and does not
1082 	 * respond to the DO ECHO we sent, (after all, we did send the
1083 	 * DO NAWS negotiation after the DO ECHO, and we won't get here
1084 	 * until a response to the DO NAWS comes back) simulate the
1085 	 * receipt of a will echo.  This will also send a WONT ECHO
1086 	 * to the client, since we assume that the client failed to
1087 	 * respond because it believes that it is already in DO ECHO
1088 	 * mode, which we do not want.
1089 	 */
1090 	if (his_want_state_is_will(TELOPT_ECHO)) {
1091 		DIAG(TD_OPTIONS,
1092 			{output_data("td: simulating recv\r\n");});
1093 		willoption(TELOPT_ECHO);
1094 	}
1095 
1096 	/*
1097 	 * Finally, to clean things up, we turn on our echo.  This
1098 	 * will break stupid 4.2 telnets out of local terminal echo.
1099 	 */
1100 
1101 	if (my_state_is_wont(TELOPT_ECHO))
1102 		send_will(TELOPT_ECHO, 1);
1103 
1104 #ifndef	STREAMSPTY
1105 	/*
1106 	 * Turn on packet mode
1107 	 */
1108 	(void) ioctl(p, TIOCPKT, (char *)&on);
1109 #endif
1110 
1111 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
1112 	/*
1113 	 * Continuing line mode support.  If client does not support
1114 	 * real linemode, attempt to negotiate kludge linemode by sending
1115 	 * the do timing mark sequence.
1116 	 */
1117 	if (lmodetype < REAL_LINEMODE)
1118 		send_do(TELOPT_TM, 1);
1119 #endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1120 
1121 	/*
1122 	 * Call telrcv() once to pick up anything received during
1123 	 * terminal type negotiation, 4.2/4.3 determination, and
1124 	 * linemode negotiation.
1125 	 */
1126 	telrcv();
1127 
1128 	(void) ioctl(f, FIONBIO, (char *)&on);
1129 	(void) ioctl(p, FIONBIO, (char *)&on);
1130 
1131 #if	defined(SO_OOBINLINE)
1132 	(void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
1133 				(char *)&on, sizeof on);
1134 #endif	/* defined(SO_OOBINLINE) */
1135 
1136 #ifdef	SIGTSTP
1137 	(void) signal(SIGTSTP, SIG_IGN);
1138 #endif
1139 #ifdef	SIGTTOU
1140 	/*
1141 	 * Ignoring SIGTTOU keeps the kernel from blocking us
1142 	 * in ttioct() in /sys/tty.c.
1143 	 */
1144 	(void) signal(SIGTTOU, SIG_IGN);
1145 #endif
1146 
1147 	(void) signal(SIGCHLD, cleanup);
1148 
1149 
1150 #ifdef  TIOCNOTTY
1151 	{
1152 		register int t;
1153 		t = open(_PATH_TTY, O_RDWR);
1154 		if (t >= 0) {
1155 			(void) ioctl(t, TIOCNOTTY, (char *)0);
1156 			(void) close(t);
1157 		}
1158 	}
1159 #endif
1160 
1161 
1162 	/*
1163 	 * Show banner that getty never gave.
1164 	 *
1165 	 * We put the banner in the pty input buffer.  This way, it
1166 	 * gets carriage return null processing, etc., just like all
1167 	 * other pty --> client data.
1168 	 */
1169 
1170 	if (getenv("USER"))
1171 		hostinfo = 0;
1172 
1173 	if (getent(defent, gettyname) == 1) {
1174 		char *cp=defstrs;
1175 
1176 		HE = getstr("he", &cp);
1177 		HN = getstr("hn", &cp);
1178 		IM = getstr("im", &cp);
1179 		IF = getstr("if", &cp);
1180 		if (HN && *HN)
1181 			(void)strlcpy(host_name, HN, sizeof(host_name));
1182 		if (IM == 0)
1183 			IM = "";
1184 	} else {
1185 		IM = DEFAULT_IM;
1186 		HE = 0;
1187 	}
1188 	edithost(HE, host_name);
1189 	ptyibuf2ptr = ptyibuf2;
1190 	if (hostinfo) {
1191 		if (IF)	{
1192 			char buf[_POSIX2_LINE_MAX];
1193 			FILE *fd;
1194 
1195 			if ((fd = fopen(IF, "r")) != NULL) {
1196 				while (fgets(buf, sizeof(buf) - 1, fd) != NULL)
1197 					ptyibuf2ptr = putf(buf, ptyibuf2ptr);
1198 				fclose(fd);
1199 			}
1200 		}
1201 		if (*IM)
1202 			ptyibuf2ptr = putf(IM, ptyibuf2ptr);
1203 	}
1204 
1205 	if (pcc)
1206 		strncpy(ptyibuf2ptr, ptyip, pcc+1);
1207 	ptyip = ptyibuf2;
1208 	pcc = strlen(ptyip);
1209 #ifdef	LINEMODE
1210 	/*
1211 	 * Last check to make sure all our states are correct.
1212 	 */
1213 	init_termbuf();
1214 	localstat();
1215 #endif	/* LINEMODE */
1216 
1217 	DIAG(TD_REPORT,
1218 		{output_data("td: Entering processing loop\r\n");});
1219 
1220 #ifdef	convex
1221 	startslave(host);
1222 #endif
1223 
1224 	nfd = ((f > p) ? f : p) + 1;
1225 	for (;;) {
1226 		fd_set ibits, obits, xbits;
1227 		register int c;
1228 
1229 		if (ncc < 0 && pcc < 0)
1230 			break;
1231 
1232 		FD_ZERO(&ibits);
1233 		FD_ZERO(&obits);
1234 		FD_ZERO(&xbits);
1235 
1236 		if (f >= FD_SETSIZE)
1237 			fatal(net, "fd too large");
1238 		if (p >= FD_SETSIZE)
1239 			fatal(net, "fd too large");
1240 
1241 		/*
1242 		 * Never look for input if there's still
1243 		 * stuff in the corresponding output buffer
1244 		 */
1245 		if (nfrontp - nbackp || pcc > 0) {
1246 			FD_SET(f, &obits);
1247 		} else {
1248 			FD_SET(p, &ibits);
1249 		}
1250 		if (pfrontp - pbackp || ncc > 0) {
1251 			FD_SET(p, &obits);
1252 		} else {
1253 			FD_SET(f, &ibits);
1254 		}
1255 		if (!SYNCHing) {
1256 			FD_SET(f, &xbits);
1257 		}
1258 		if ((c = select(nfd, &ibits, &obits, &xbits,
1259 						(struct timeval *)0)) < 1) {
1260 			if (c == -1) {
1261 				if (errno == EINTR) {
1262 					continue;
1263 				}
1264 			}
1265 			sleep(5);
1266 			continue;
1267 		}
1268 
1269 		/*
1270 		 * Any urgent data?
1271 		 */
1272 		if (FD_ISSET(net, &xbits)) {
1273 		    SYNCHing = 1;
1274 		}
1275 
1276 		/*
1277 		 * Something to read from the network...
1278 		 */
1279 		if (FD_ISSET(net, &ibits)) {
1280 #if	!defined(SO_OOBINLINE)
1281 			/*
1282 			 * In 4.2 (and 4.3 beta) systems, the
1283 			 * OOB indication and data handling in the kernel
1284 			 * is such that if two separate TCP Urgent requests
1285 			 * come in, one byte of TCP data will be overlaid.
1286 			 * This is fatal for Telnet, but we try to live
1287 			 * with it.
1288 			 *
1289 			 * In addition, in 4.2 (and...), a special protocol
1290 			 * is needed to pick up the TCP Urgent data in
1291 			 * the correct sequence.
1292 			 *
1293 			 * What we do is:  if we think we are in urgent
1294 			 * mode, we look to see if we are "at the mark".
1295 			 * If we are, we do an OOB receive.  If we run
1296 			 * this twice, we will do the OOB receive twice,
1297 			 * but the second will fail, since the second
1298 			 * time we were "at the mark", but there wasn't
1299 			 * any data there (the kernel doesn't reset
1300 			 * "at the mark" until we do a normal read).
1301 			 * Once we've read the OOB data, we go ahead
1302 			 * and do normal reads.
1303 			 *
1304 			 * There is also another problem, which is that
1305 			 * since the OOB byte we read doesn't put us
1306 			 * out of OOB state, and since that byte is most
1307 			 * likely the TELNET DM (data mark), we would
1308 			 * stay in the TELNET SYNCH (SYNCHing) state.
1309 			 * So, clocks to the rescue.  If we've "just"
1310 			 * received a DM, then we test for the
1311 			 * presence of OOB data when the receive OOB
1312 			 * fails (and AFTER we did the normal mode read
1313 			 * to clear "at the mark").
1314 			 */
1315 		    if (SYNCHing) {
1316 			int atmark;
1317 
1318 			(void) ioctl(net, SIOCATMARK, (char *)&atmark);
1319 			if (atmark) {
1320 			    ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
1321 			    if ((ncc == -1) && (errno == EINVAL)) {
1322 				ncc = read(net, netibuf, sizeof (netibuf));
1323 				if (sequenceIs(didnetreceive, gotDM)) {
1324 				    SYNCHing = stilloob(net);
1325 				}
1326 			    }
1327 			} else {
1328 			    ncc = read(net, netibuf, sizeof (netibuf));
1329 			}
1330 		    } else {
1331 			ncc = read(net, netibuf, sizeof (netibuf));
1332 		    }
1333 		    settimer(didnetreceive);
1334 #else	/* !defined(SO_OOBINLINE)) */
1335 		    ncc = read(net, netibuf, sizeof (netibuf));
1336 #endif	/* !defined(SO_OOBINLINE)) */
1337 		    if (ncc < 0 && errno == EWOULDBLOCK)
1338 			ncc = 0;
1339 		    else {
1340 			if (ncc <= 0) {
1341 			    break;
1342 			}
1343 			netip = netibuf;
1344 		    }
1345 		    DIAG((TD_REPORT | TD_NETDATA),
1346 			    {output_data("td: netread %d chars\r\n", ncc);});
1347 		    DIAG(TD_NETDATA, printdata("nd", netip, ncc));
1348 		}
1349 
1350 		/*
1351 		 * Something to read from the pty...
1352 		 */
1353 		if (FD_ISSET(p, &ibits)) {
1354 #ifndef	STREAMSPTY
1355 			pcc = read(p, ptyibuf, BUFSIZ);
1356 #else
1357 			pcc = readstream(p, ptyibuf, BUFSIZ);
1358 #endif
1359 			/*
1360 			 * On some systems, if we try to read something
1361 			 * off the master side before the slave side is
1362 			 * opened, we get EIO.
1363 			 */
1364 			if (pcc < 0 && (errno == EWOULDBLOCK ||
1365 #ifdef	EAGAIN
1366 					errno == EAGAIN ||
1367 #endif
1368 					errno == EIO)) {
1369 				pcc = 0;
1370 			} else {
1371 				if (pcc <= 0)
1372 					break;
1373 #ifdef	LINEMODE
1374 				/*
1375 				 * If ioctl from pty, pass it through net
1376 				 */
1377 				if (ptyibuf[0] & TIOCPKT_IOCTL) {
1378 					copy_termbuf(ptyibuf+1, pcc-1);
1379 					localstat();
1380 					pcc = 1;
1381 				}
1382 #endif	/* LINEMODE */
1383 				if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
1384 					netclear();	/* clear buffer back */
1385 #ifndef	NO_URGENT
1386 					/*
1387 					 * There are client telnets on some
1388 					 * operating systems get screwed up
1389 					 * royally if we send them urgent
1390 					 * mode data.
1391 					 */
1392 					output_data("%c%c", IAC, DM);
1393 					neturg = nfrontp - 1; /* off by one XXX */
1394 					DIAG(TD_OPTIONS,
1395 					    printoption("td: send IAC", DM));
1396 
1397 #endif
1398 				}
1399 				if (his_state_is_will(TELOPT_LFLOW) &&
1400 				    (ptyibuf[0] &
1401 				     (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
1402 					int newflow =
1403 					    ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
1404 					if (newflow != flowmode) {
1405 						flowmode = newflow;
1406 						(void) output_data(
1407 							"%c%c%c%c%c%c",
1408 							IAC, SB, TELOPT_LFLOW,
1409 							flowmode ? LFLOW_ON
1410 								 : LFLOW_OFF,
1411 							IAC, SE);
1412 						DIAG(TD_OPTIONS, printsub('>',
1413 						    (unsigned char *)nfrontp - 4,
1414 						    4););
1415 					}
1416 				}
1417 				pcc--;
1418 				ptyip = ptyibuf+1;
1419 			}
1420 		}
1421 
1422 		while (pcc > 0) {
1423 			if ((&netobuf[BUFSIZ] - nfrontp) < 2)
1424 				break;
1425 			c = *ptyip++ & 0377, pcc--;
1426 			if (c == IAC)
1427 				output_data("%c", c);
1428 			output_data("%c", c);
1429 			if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
1430 				if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
1431 					output_data("%c", *ptyip++ & 0377);
1432 					pcc--;
1433 				} else
1434 					output_datalen("\0", 1);
1435 			}
1436 		}
1437 
1438 		if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
1439 			netflush();
1440 		if (ncc > 0)
1441 			telrcv();
1442 		if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
1443 			ptyflush();
1444 	}
1445 	cleanup(0);
1446 }  /* end of telnet */
1447 
1448 #ifndef	TCSIG
1449 # ifdef	TIOCSIG
1450 #  define TCSIG TIOCSIG
1451 # endif
1452 #endif
1453 
1454 #ifdef	STREAMSPTY
1455 
1456 int flowison = -1;  /* current state of flow: -1 is unknown */
1457 
1458 int readstream(p, ibuf, bufsize)
1459 	int p;
1460 	char *ibuf;
1461 	int bufsize;
1462 {
1463 	int flags = 0;
1464 	int ret = 0;
1465 	struct termios *tsp;
1466 	struct termio *tp;
1467 	struct iocblk *ip;
1468 	char vstop, vstart;
1469 	int ixon;
1470 	int newflow;
1471 
1472 	strbufc.maxlen = BUFSIZ;
1473 	strbufc.buf = (char *)ctlbuf;
1474 	strbufd.maxlen = bufsize-1;
1475 	strbufd.len = 0;
1476 	strbufd.buf = ibuf+1;
1477 	ibuf[0] = 0;
1478 
1479 	ret = getmsg(p, &strbufc, &strbufd, &flags);
1480 	if (ret < 0)  /* error of some sort -- probably EAGAIN */
1481 		return(-1);
1482 
1483 	if (strbufc.len <= 0 || ctlbuf[0] == M_DATA) {
1484 		/* data message */
1485 		if (strbufd.len > 0) {			/* real data */
1486 			return(strbufd.len + 1);	/* count header char */
1487 		} else {
1488 			/* nothing there */
1489 			errno = EAGAIN;
1490 			return(-1);
1491 		}
1492 	}
1493 
1494 	/*
1495 	 * It's a control message.  Return 1, to look at the flag we set
1496 	 */
1497 
1498 	switch (ctlbuf[0]) {
1499 	case M_FLUSH:
1500 		if (ibuf[1] & FLUSHW)
1501 			ibuf[0] = TIOCPKT_FLUSHWRITE;
1502 		return(1);
1503 
1504 	case M_IOCTL:
1505 		ip = (struct iocblk *) (ibuf+1);
1506 
1507 		switch (ip->ioc_cmd) {
1508 		case TCSETS:
1509 		case TCSETSW:
1510 		case TCSETSF:
1511 			tsp = (struct termios *)
1512 					(ibuf+1 + sizeof(struct iocblk));
1513 			vstop = tsp->c_cc[VSTOP];
1514 			vstart = tsp->c_cc[VSTART];
1515 			ixon = tsp->c_iflag & IXON;
1516 			break;
1517 		case TCSETA:
1518 		case TCSETAW:
1519 		case TCSETAF:
1520 			tp = (struct termio *) (ibuf+1 + sizeof(struct iocblk));
1521 			vstop = tp->c_cc[VSTOP];
1522 			vstart = tp->c_cc[VSTART];
1523 			ixon = tp->c_iflag & IXON;
1524 			break;
1525 		default:
1526 			errno = EAGAIN;
1527 			return(-1);
1528 		}
1529 
1530 		newflow =  (ixon && (vstart == 021) && (vstop == 023)) ? 1 : 0;
1531 		if (newflow != flowison) {  /* it's a change */
1532 			flowison = newflow;
1533 			ibuf[0] = newflow ? TIOCPKT_DOSTOP : TIOCPKT_NOSTOP;
1534 			return(1);
1535 		}
1536 	}
1537 
1538 	/* nothing worth doing anything about */
1539 	errno = EAGAIN;
1540 	return(-1);
1541 }
1542 #endif /* STREAMSPTY */
1543 
1544 /*
1545  * Send interrupt to process on other side of pty.
1546  * If it is in raw mode, just write NULL;
1547  * otherwise, write intr char.
1548  */
1549 	void
1550 interrupt()
1551 {
1552 	ptyflush();	/* half-hearted */
1553 
1554 #if defined(STREAMSPTY) && defined(TIOCSIGNAL)
1555 	/* Streams PTY style ioctl to post a signal */
1556 	{
1557 		int sig = SIGINT;
1558 		(void) ioctl(pty, TIOCSIGNAL, &sig);
1559 		(void) ioctl(pty, I_FLUSH, FLUSHR);
1560 	}
1561 #else
1562 #ifdef	TCSIG
1563 	(void) ioctl(pty, TCSIG, (char *)SIGINT);
1564 #else	/* TCSIG */
1565 	init_termbuf();
1566 	*pfrontp++ = slctab[SLC_IP].sptr ?
1567 			(unsigned char)*slctab[SLC_IP].sptr : '\177';
1568 #endif	/* TCSIG */
1569 #endif
1570 }
1571 
1572 /*
1573  * Send quit to process on other side of pty.
1574  * If it is in raw mode, just write NULL;
1575  * otherwise, write quit char.
1576  */
1577 	void
1578 sendbrk()
1579 {
1580 	ptyflush();	/* half-hearted */
1581 #ifdef	TCSIG
1582 	(void) ioctl(pty, TCSIG, (char *)SIGQUIT);
1583 #else	/* TCSIG */
1584 	init_termbuf();
1585 	*pfrontp++ = slctab[SLC_ABORT].sptr ?
1586 			(unsigned char)*slctab[SLC_ABORT].sptr : '\034';
1587 #endif	/* TCSIG */
1588 }
1589 
1590 	void
1591 sendsusp()
1592 {
1593 #ifdef	SIGTSTP
1594 	ptyflush();	/* half-hearted */
1595 # ifdef	TCSIG
1596 	(void) ioctl(pty, TCSIG, (char *)SIGTSTP);
1597 # else	/* TCSIG */
1598 	*pfrontp++ = slctab[SLC_SUSP].sptr ?
1599 			(unsigned char)*slctab[SLC_SUSP].sptr : '\032';
1600 # endif	/* TCSIG */
1601 #endif	/* SIGTSTP */
1602 }
1603 
1604 /*
1605  * When we get an AYT, if ^T is enabled, use that.  Otherwise,
1606  * just send back "[Yes]".
1607  */
1608 	void
1609 recv_ayt()
1610 {
1611 #if	defined(SIGINFO) && defined(TCSIG)
1612 	if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
1613 		(void) ioctl(pty, TCSIG, (char *)SIGINFO);
1614 		return;
1615 	}
1616 #endif
1617 	(void) output_data("\r\n[Yes]\r\n");
1618 }
1619 
1620 	void
1621 doeof()
1622 {
1623 	init_termbuf();
1624 
1625 #if	defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
1626 	if (!tty_isediting()) {
1627 		extern char oldeofc;
1628 		*pfrontp++ = oldeofc;
1629 		return;
1630 	}
1631 #endif
1632 	*pfrontp++ = slctab[SLC_EOF].sptr ?
1633 			(unsigned char)*slctab[SLC_EOF].sptr : '\004';
1634 }
1635