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telnetd.c revision 1.17
      1 /*	$NetBSD: telnetd.c,v 1.17 1999/07/11 03:00:07 thorpej 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 1.17 1999/07/11 03:00:07 thorpej 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 #define P __P
     85 
     86 #if	defined(_SC_CRAY_SECURE_SYS) && !defined(SCM_SECURITY)
     87 /*
     88  * UNICOS 6.0/6.1 do not have SCM_SECURITY defined, so we can
     89  * use it to tell us to turn off all the socket security code,
     90  * since that is only used in UNICOS 7.0 and later.
     91  */
     92 # undef _SC_CRAY_SECURE_SYS
     93 #endif
     94 
     95 #if	defined(_SC_CRAY_SECURE_SYS)
     96 #include <sys/sysv.h>
     97 #include <sys/secdev.h>
     98 # ifdef SO_SEC_MULTI		/* 8.0 code */
     99 #include <sys/secparm.h>
    100 #include <sys/usrv.h>
    101 # endif /* SO_SEC_MULTI */
    102 int	secflag;
    103 char	tty_dev[16];
    104 struct	secdev dv;
    105 struct	sysv sysv;
    106 # ifdef SO_SEC_MULTI		/* 8.0 code */
    107 struct	socksec ss;
    108 # else /* SO_SEC_MULTI */	/* 7.0 code */
    109 struct	socket_security ss;
    110 # endif /* SO_SEC_MULTI */
    111 #endif	/* _SC_CRAY_SECURE_SYS */
    112 
    113 #if	defined(AUTHENTICATION)
    114 #include <libtelnet/auth.h>
    115 int	auth_level = 0;
    116 #endif
    117 #if	defined(SECURELOGIN)
    118 int	require_secure_login = 0;
    119 #endif
    120 
    121 extern	int utmp_len;
    122 int	registerd_host_only = 0;
    123 
    124 #ifdef	STREAMSPTY
    125 # include <stropts.h>
    126 # include <termio.h>
    127 /* make sure we don't get the bsd version */
    128 # include "/usr/include/sys/tty.h"
    129 # include <sys/ptyvar.h>
    130 
    131 /*
    132  * Because of the way ptyibuf is used with streams messages, we need
    133  * ptyibuf+1 to be on a full-word boundary.  The following wierdness
    134  * is simply to make that happen.
    135  */
    136 long	ptyibufbuf[BUFSIZ/sizeof(long)+1];
    137 char	*ptyibuf = ((char *)&ptyibufbuf[1])-1;
    138 char	*ptyip = ((char *)&ptyibufbuf[1])-1;
    139 char	ptyibuf2[BUFSIZ];
    140 unsigned char ctlbuf[BUFSIZ];
    141 struct	strbuf strbufc, strbufd;
    142 
    143 int readstream();
    144 
    145 #else	/* ! STREAMPTY */
    146 
    147 /*
    148  * I/O data buffers,
    149  * pointers, and counters.
    150  */
    151 char	ptyibuf[BUFSIZ], *ptyip = ptyibuf;
    152 char	ptyibuf2[BUFSIZ];
    153 
    154 #endif /* ! STREAMPTY */
    155 
    156 int	hostinfo = 1;			/* do we print login banner? */
    157 
    158 #ifdef	CRAY
    159 extern int      newmap; /* nonzero if \n maps to ^M^J */
    160 int	lowpty = 0, highpty;	/* low, high pty numbers */
    161 #endif /* CRAY */
    162 
    163 int debug = 0;
    164 int keepalive = 1;
    165 char *gettyname = "default";
    166 char *progname;
    167 
    168 extern void usage P((void));
    169 int main __P((int, char *[]));
    170 void usage __P((void));
    171 int getterminaltype __P((char *));
    172 int getent __P((char *, char *));
    173 void doit __P((struct sockaddr *));
    174 void _gettermname __P((void));
    175 int terminaltypeok __P((char *));
    176 char *getstr __P((char *, char **));
    177 
    178 /*
    179  * The string to pass to getopt().  We do it this way so
    180  * that only the actual options that we support will be
    181  * passed off to getopt().
    182  */
    183 char valid_opts[] = {
    184 	'd', ':', 'g', ':', 'h', 'k', 'n', 'S', ':', 'u', ':', 'U',
    185 	'4', '6',
    186 #ifdef	AUTHENTICATION
    187 	'a', ':', 'X', ':',
    188 #endif
    189 #ifdef BFTPDAEMON
    190 	'B',
    191 #endif
    192 #ifdef DIAGNOSTICS
    193 	'D', ':',
    194 #endif
    195 #if	defined(CRAY) && defined(NEWINIT)
    196 	'I', ':',
    197 #endif
    198 #ifdef	LINEMODE
    199 	'l',
    200 #endif
    201 #ifdef CRAY
    202 	'r', ':',
    203 #endif
    204 #ifdef	SECURELOGIN
    205 	's',
    206 #endif
    207 	'\0'
    208 };
    209 
    210 int family = AF_INET;
    211 
    212 int
    213 main(argc, argv)
    214 	int argc;
    215 	char *argv[];
    216 {
    217 	struct sockaddr_storage from;
    218 	int on = 1, fromlen;
    219 	register int ch;
    220 #if	defined(IPPROTO_IP) && defined(IP_TOS)
    221 	int tos = -1;
    222 #endif
    223 
    224 	pfrontp = pbackp = ptyobuf;
    225 	netip = netibuf;
    226 	nfrontp = nbackp = netobuf;
    227 
    228 	progname = *argv;
    229 
    230 #ifdef CRAY
    231 	/*
    232 	 * Get number of pty's before trying to process options,
    233 	 * which may include changing pty range.
    234 	 */
    235 	highpty = getnpty();
    236 #endif /* CRAY */
    237 
    238 	while ((ch = getopt(argc, argv, valid_opts)) != -1) {
    239 		switch (ch) {
    240 
    241 #ifdef	AUTHENTICATION
    242 		case 'a':
    243 			/*
    244 			 * Check for required authentication level
    245 			 */
    246 			if (strcmp(optarg, "debug") == 0) {
    247 				extern int auth_debug_mode;
    248 				auth_debug_mode = 1;
    249 			} else if (strcasecmp(optarg, "none") == 0) {
    250 				auth_level = 0;
    251 			} else if (strcasecmp(optarg, "other") == 0) {
    252 				auth_level = AUTH_OTHER;
    253 			} else if (strcasecmp(optarg, "user") == 0) {
    254 				auth_level = AUTH_USER;
    255 			} else if (strcasecmp(optarg, "valid") == 0) {
    256 				auth_level = AUTH_VALID;
    257 			} else if (strcasecmp(optarg, "off") == 0) {
    258 				/*
    259 				 * This hack turns off authentication
    260 				 */
    261 				auth_level = -1;
    262 			} else {
    263 				fprintf(stderr,
    264 			    "telnetd: unknown authorization level for -a\n");
    265 			}
    266 			break;
    267 #endif	/* AUTHENTICATION */
    268 
    269 #ifdef BFTPDAEMON
    270 		case 'B':
    271 			bftpd++;
    272 			break;
    273 #endif /* BFTPDAEMON */
    274 
    275 		case 'd':
    276 			if (strcmp(optarg, "ebug") == 0) {
    277 				debug++;
    278 				break;
    279 			}
    280 			usage();
    281 			/* NOTREACHED */
    282 			break;
    283 
    284 #ifdef DIAGNOSTICS
    285 		case 'D':
    286 			/*
    287 			 * Check for desired diagnostics capabilities.
    288 			 */
    289 			if (!strcmp(optarg, "report")) {
    290 				diagnostic |= TD_REPORT|TD_OPTIONS;
    291 			} else if (!strcmp(optarg, "exercise")) {
    292 				diagnostic |= TD_EXERCISE;
    293 			} else if (!strcmp(optarg, "netdata")) {
    294 				diagnostic |= TD_NETDATA;
    295 			} else if (!strcmp(optarg, "ptydata")) {
    296 				diagnostic |= TD_PTYDATA;
    297 			} else if (!strcmp(optarg, "options")) {
    298 				diagnostic |= TD_OPTIONS;
    299 			} else {
    300 				usage();
    301 				/* NOT REACHED */
    302 			}
    303 			break;
    304 #endif /* DIAGNOSTICS */
    305 
    306 		case 'g':
    307 			gettyname = optarg;
    308 			break;
    309 
    310 		case 'h':
    311 			hostinfo = 0;
    312 			break;
    313 
    314 #if	defined(CRAY) && defined(NEWINIT)
    315 		case 'I':
    316 		    {
    317 			extern char *gen_id;
    318 			gen_id = optarg;
    319 			break;
    320 		    }
    321 #endif	/* defined(CRAY) && defined(NEWINIT) */
    322 
    323 #ifdef	LINEMODE
    324 		case 'l':
    325 			alwayslinemode = 1;
    326 			break;
    327 #endif	/* LINEMODE */
    328 
    329 		case 'k':
    330 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
    331 			lmodetype = NO_AUTOKLUDGE;
    332 #else
    333 			/* ignore -k option if built without kludge linemode */
    334 #endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
    335 			break;
    336 
    337 		case 'n':
    338 			keepalive = 0;
    339 			break;
    340 
    341 #ifdef CRAY
    342 		case 'r':
    343 		    {
    344 			char *strchr();
    345 			char *c;
    346 
    347 			/*
    348 			 * Allow the specification of alterations
    349 			 * to the pty search range.  It is legal to
    350 			 * specify only one, and not change the
    351 			 * other from its default.
    352 			 */
    353 			c = strchr(optarg, '-');
    354 			if (c) {
    355 				*c++ = '\0';
    356 				highpty = atoi(c);
    357 			}
    358 			if (*optarg != '\0')
    359 				lowpty = atoi(optarg);
    360 			if ((lowpty > highpty) || (lowpty < 0) ||
    361 							(highpty > 32767)) {
    362 				usage();
    363 				/* NOT REACHED */
    364 			}
    365 			break;
    366 		    }
    367 #endif	/* CRAY */
    368 
    369 #ifdef	SECURELOGIN
    370 		case 's':
    371 			/* Secure login required */
    372 			require_secure_login = 1;
    373 			break;
    374 #endif	/* SECURELOGIN */
    375 		case 'S':
    376 #ifdef	HAS_GETTOS
    377 			if ((tos = parsetos(optarg, "tcp")) < 0)
    378 				fprintf(stderr, "%s%s%s\n",
    379 					"telnetd: Bad TOS argument '", optarg,
    380 					"'; will try to use default TOS");
    381 #else
    382 			fprintf(stderr, "%s%s\n", "TOS option unavailable; ",
    383 						"-S flag not supported\n");
    384 #endif
    385 			break;
    386 
    387 		case 'u':
    388 			utmp_len = atoi(optarg);
    389 			break;
    390 
    391 		case 'U':
    392 			registerd_host_only = 1;
    393 			break;
    394 
    395 #ifdef	AUTHENTICATION
    396 		case 'X':
    397 			/*
    398 			 * Check for invalid authentication types
    399 			 */
    400 			auth_disable_name(optarg);
    401 			break;
    402 #endif	/* AUTHENTICATION */
    403 
    404 		case '4':
    405 			family = AF_INET;
    406 			break;
    407 
    408 		case '6':
    409 			family = AF_INET6;
    410 			break;
    411 
    412 		default:
    413 			fprintf(stderr, "telnetd: %c: unknown option\n", ch);
    414 			/* FALLTHROUGH */
    415 		case '?':
    416 			usage();
    417 			/* NOTREACHED */
    418 		}
    419 	}
    420 
    421 	argc -= optind;
    422 	argv += optind;
    423 
    424 	if (debug) {
    425 	    int s, ns, foo, error;
    426 	    char *service = "telnet";
    427 	    struct addrinfo hints, *res;
    428 
    429 	    if (argc > 1) {
    430 		usage();
    431 		/* NOT REACHED */
    432 	    } else if (argc == 1)
    433 		service = *argv;
    434 
    435 	    memset(&hints, 0, sizeof(hints));
    436 	    hints.ai_flags = AI_PASSIVE;
    437 	    hints.ai_family = family;
    438 	    hints.ai_socktype = SOCK_STREAM;
    439 	    hints.ai_protocol = 0;
    440 	    error = getaddrinfo(NULL, service, &hints, &res);
    441 
    442 	    if (error) {
    443 		errx(1, "tcp/%s: %s\n", service, gai_strerror(error));
    444 		usage();
    445 	    }
    446 
    447 	    s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    448 	    if (s < 0) {
    449 		    perror("telnetd: socket");;
    450 		    exit(1);
    451 	    }
    452 	    (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
    453 				(char *)&on, sizeof(on));
    454 	    if (bind(s, res->ai_addr, res->ai_addrlen) < 0) {
    455 		perror("bind");
    456 		exit(1);
    457 	    }
    458 	    if (listen(s, 1) < 0) {
    459 		perror("listen");
    460 		exit(1);
    461 	    }
    462 	    foo = res->ai_addrlen;
    463 	    ns = accept(s, res->ai_addr, &foo);
    464 	    if (ns < 0) {
    465 		perror("accept");
    466 		exit(1);
    467 	    }
    468 	    (void) dup2(ns, 0);
    469 	    (void) close(ns);
    470 	    (void) close(s);
    471 #ifdef convex
    472 	} else if (argc == 1) {
    473 		; /* VOID*/		/* Just ignore the host/port name */
    474 #endif
    475 	} else if (argc > 0) {
    476 		usage();
    477 		/* NOT REACHED */
    478 	}
    479 
    480 #if	defined(_SC_CRAY_SECURE_SYS)
    481 	secflag = sysconf(_SC_CRAY_SECURE_SYS);
    482 
    483 	/*
    484 	 *	Get socket's security label
    485 	 */
    486 	if (secflag)  {
    487 		int szss = sizeof(ss);
    488 #ifdef SO_SEC_MULTI			/* 8.0 code */
    489 		int sock_multi;
    490 		int szi = sizeof(int);
    491 #endif /* SO_SEC_MULTI */
    492 
    493 		memset((char *)&dv, 0, sizeof(dv));
    494 
    495 		if (getsysv(&sysv, sizeof(struct sysv)) != 0) {
    496 			perror("getsysv");
    497 			exit(1);
    498 		}
    499 
    500 		/*
    501 		 *	Get socket security label and set device values
    502 		 *	   {security label to be set on ttyp device}
    503 		 */
    504 #ifdef SO_SEC_MULTI			/* 8.0 code */
    505 		if ((getsockopt(0, SOL_SOCKET, SO_SECURITY,
    506 			       (char *)&ss, &szss) < 0) ||
    507 		    (getsockopt(0, SOL_SOCKET, SO_SEC_MULTI,
    508 				(char *)&sock_multi, &szi) < 0)) {
    509 			perror("getsockopt");
    510 			exit(1);
    511 		} else {
    512 			dv.dv_actlvl = ss.ss_actlabel.lt_level;
    513 			dv.dv_actcmp = ss.ss_actlabel.lt_compart;
    514 			if (!sock_multi) {
    515 				dv.dv_minlvl = dv.dv_maxlvl = dv.dv_actlvl;
    516 				dv.dv_valcmp = dv.dv_actcmp;
    517 			} else {
    518 				dv.dv_minlvl = ss.ss_minlabel.lt_level;
    519 				dv.dv_maxlvl = ss.ss_maxlabel.lt_level;
    520 				dv.dv_valcmp = ss.ss_maxlabel.lt_compart;
    521 			}
    522 			dv.dv_devflg = 0;
    523 		}
    524 #else /* SO_SEC_MULTI */		/* 7.0 code */
    525 		if (getsockopt(0, SOL_SOCKET, SO_SECURITY,
    526 				(char *)&ss, &szss) >= 0) {
    527 			dv.dv_actlvl = ss.ss_slevel;
    528 			dv.dv_actcmp = ss.ss_compart;
    529 			dv.dv_minlvl = ss.ss_minlvl;
    530 			dv.dv_maxlvl = ss.ss_maxlvl;
    531 			dv.dv_valcmp = ss.ss_maxcmp;
    532 		}
    533 #endif /* SO_SEC_MULTI */
    534 	}
    535 #endif	/* _SC_CRAY_SECURE_SYS */
    536 
    537 	openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
    538 	fromlen = sizeof (from);
    539 	if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
    540 		fprintf(stderr, "%s: ", progname);
    541 		perror("getpeername");
    542 		_exit(1);
    543 	}
    544 	if (keepalive &&
    545 	    setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
    546 			(char *)&on, sizeof (on)) < 0) {
    547 		syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
    548 	}
    549 
    550 #if	defined(IPPROTO_IP) && defined(IP_TOS)
    551 	if (from.__ss_family == AF_INET) {
    552 # if	defined(HAS_GETTOS)
    553 		struct tosent *tp;
    554 		if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
    555 			tos = tp->t_tos;
    556 # endif
    557 		if (tos < 0)
    558 			tos = 020;	/* Low Delay bit */
    559 		if (tos
    560 		   && (setsockopt(0, IPPROTO_IP, IP_TOS,
    561 				  (char *)&tos, sizeof(tos)) < 0)
    562 		   && (errno != ENOPROTOOPT) )
    563 			syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
    564 	}
    565 #endif	/* defined(IPPROTO_IP) && defined(IP_TOS) */
    566 
    567 	net = 0;
    568 	doit((struct sockaddr *)&from);
    569 	/* NOTREACHED */
    570 #ifdef __GNUC__
    571 	exit(0);
    572 #endif
    573 }  /* end of main */
    574 
    575 	void
    576 usage()
    577 {
    578 	fprintf(stderr, "Usage: telnetd");
    579 #ifdef	AUTHENTICATION
    580 	fprintf(stderr, " [-a (debug|other|user|valid|off|none)]\n\t");
    581 #endif
    582 #ifdef BFTPDAEMON
    583 	fprintf(stderr, " [-B]");
    584 #endif
    585 	fprintf(stderr, " [-debug]");
    586 #ifdef DIAGNOSTICS
    587 	fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
    588 #endif
    589 #ifdef	AUTHENTICATION
    590 	fprintf(stderr, " [-edebug]");
    591 #endif
    592 	fprintf(stderr, " [-h]");
    593 #if	defined(CRAY) && defined(NEWINIT)
    594 	fprintf(stderr, " [-Iinitid]");
    595 #endif
    596 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
    597 	fprintf(stderr, " [-k]");
    598 #endif
    599 #ifdef LINEMODE
    600 	fprintf(stderr, " [-l]");
    601 #endif
    602 	fprintf(stderr, " [-n]");
    603 #ifdef	CRAY
    604 	fprintf(stderr, " [-r[lowpty]-[highpty]]");
    605 #endif
    606 	fprintf(stderr, "\n\t");
    607 #ifdef	SECURELOGIN
    608 	fprintf(stderr, " [-s]");
    609 #endif
    610 #ifdef	HAS_GETTOS
    611 	fprintf(stderr, " [-S tos]");
    612 #endif
    613 #ifdef	AUTHENTICATION
    614 	fprintf(stderr, " [-X auth-type]");
    615 #endif
    616 	fprintf(stderr, " [-u utmp_hostname_length] [-U]");
    617 	fprintf(stderr, " [port]\n");
    618 	exit(1);
    619 }
    620 
    621 /*
    622  * getterminaltype
    623  *
    624  *	Ask the other end to send along its terminal type and speed.
    625  * Output is the variable terminaltype filled in.
    626  */
    627 static unsigned char ttytype_sbbuf[] = {
    628 	IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
    629 };
    630 
    631     int
    632 getterminaltype(name)
    633     char *name;
    634 {
    635     int retval = -1;
    636 
    637     settimer(baseline);
    638 #if	defined(AUTHENTICATION)
    639     /*
    640      * Handle the Authentication option before we do anything else.
    641      */
    642     send_do(TELOPT_AUTHENTICATION, 1);
    643     while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
    644 	ttloop();
    645     if (his_state_is_will(TELOPT_AUTHENTICATION)) {
    646 	retval = auth_wait(name);
    647     }
    648 #endif
    649 
    650     send_do(TELOPT_TTYPE, 1);
    651     send_do(TELOPT_TSPEED, 1);
    652     send_do(TELOPT_XDISPLOC, 1);
    653     send_do(TELOPT_NEW_ENVIRON, 1);
    654     send_do(TELOPT_OLD_ENVIRON, 1);
    655     while (
    656 	   his_will_wont_is_changing(TELOPT_TTYPE) ||
    657 	   his_will_wont_is_changing(TELOPT_TSPEED) ||
    658 	   his_will_wont_is_changing(TELOPT_XDISPLOC) ||
    659 	   his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
    660 	   his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
    661 	ttloop();
    662     }
    663     if (his_state_is_will(TELOPT_TSPEED)) {
    664 	static unsigned char sb[] =
    665 			{ IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
    666 
    667 	memmove(nfrontp, sb, sizeof sb);
    668 	nfrontp += sizeof sb;
    669 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    670     }
    671     if (his_state_is_will(TELOPT_XDISPLOC)) {
    672 	static unsigned char sb[] =
    673 			{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
    674 
    675 	memmove(nfrontp, sb, sizeof sb);
    676 	nfrontp += sizeof sb;
    677 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    678     }
    679     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
    680 	static unsigned char sb[] =
    681 			{ IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
    682 
    683 	memmove(nfrontp, sb, sizeof sb);
    684 	nfrontp += sizeof sb;
    685 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    686     }
    687     else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
    688 	static unsigned char sb[] =
    689 			{ IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
    690 
    691 	memmove(nfrontp, sb, sizeof sb);
    692 	nfrontp += sizeof sb;
    693 	DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    694     }
    695     if (his_state_is_will(TELOPT_TTYPE)) {
    696 
    697 	memmove(nfrontp, ttytype_sbbuf, sizeof ttytype_sbbuf);
    698 	nfrontp += sizeof ttytype_sbbuf;
    699 	DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
    700 					sizeof ttytype_sbbuf - 2););
    701     }
    702     if (his_state_is_will(TELOPT_TSPEED)) {
    703 	while (sequenceIs(tspeedsubopt, baseline))
    704 	    ttloop();
    705     }
    706     if (his_state_is_will(TELOPT_XDISPLOC)) {
    707 	while (sequenceIs(xdisplocsubopt, baseline))
    708 	    ttloop();
    709     }
    710     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
    711 	while (sequenceIs(environsubopt, baseline))
    712 	    ttloop();
    713     }
    714     if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
    715 	while (sequenceIs(oenvironsubopt, baseline))
    716 	    ttloop();
    717     }
    718     if (his_state_is_will(TELOPT_TTYPE)) {
    719 	char first[256], last[256];
    720 
    721 	while (sequenceIs(ttypesubopt, baseline))
    722 	    ttloop();
    723 
    724 	/*
    725 	 * If the other side has already disabled the option, then
    726 	 * we have to just go with what we (might) have already gotten.
    727 	 */
    728 	if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
    729 	    (void) strncpy(first, terminaltype, sizeof(first));
    730 	    for(;;) {
    731 		/*
    732 		 * Save the unknown name, and request the next name.
    733 		 */
    734 		(void) strncpy(last, terminaltype, sizeof(last));
    735 		_gettermname();
    736 		if (terminaltypeok(terminaltype))
    737 		    break;
    738 		if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
    739 		    his_state_is_wont(TELOPT_TTYPE)) {
    740 		    /*
    741 		     * We've hit the end.  If this is the same as
    742 		     * the first name, just go with it.
    743 		     */
    744 		    if (strncmp(first, terminaltype, sizeof(first)) == 0)
    745 			break;
    746 		    /*
    747 		     * Get the terminal name one more time, so that
    748 		     * RFC1091 compliant telnets will cycle back to
    749 		     * the start of the list.
    750 		     */
    751 		     _gettermname();
    752 		    if (strncmp(first, terminaltype, sizeof(first)) != 0)
    753 			(void) strncpy(terminaltype, first, sizeof(first));
    754 		    break;
    755 		}
    756 	    }
    757 	}
    758     }
    759     return(retval);
    760 }  /* end of getterminaltype */
    761 
    762     void
    763 _gettermname()
    764 {
    765     /*
    766      * If the client turned off the option,
    767      * we can't send another request, so we
    768      * just return.
    769      */
    770     if (his_state_is_wont(TELOPT_TTYPE))
    771 	return;
    772     settimer(baseline);
    773     memmove(nfrontp, ttytype_sbbuf, sizeof ttytype_sbbuf);
    774     nfrontp += sizeof ttytype_sbbuf;
    775     DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
    776 					sizeof ttytype_sbbuf - 2););
    777     while (sequenceIs(ttypesubopt, baseline))
    778 	ttloop();
    779 }
    780 
    781     int
    782 terminaltypeok(s)
    783     char *s;
    784 {
    785     char buf[1024];
    786 
    787     if (terminaltype == NULL)
    788 	return(1);
    789 
    790     /*
    791      * tgetent() will return 1 if the type is known, and
    792      * 0 if it is not known.  If it returns -1, it couldn't
    793      * open the database.  But if we can't open the database,
    794      * it won't help to say we failed, because we won't be
    795      * able to verify anything else.  So, we treat -1 like 1.
    796      */
    797     if (tgetent(buf, s) == 0)
    798 	return(0);
    799     return(1);
    800 }
    801 
    802 #ifndef	MAXHOSTNAMELEN
    803 #define	MAXHOSTNAMELEN 64
    804 #endif	/* MAXHOSTNAMELEN */
    805 
    806 char *hostname;
    807 char host_name[MAXHOSTNAMELEN + 1];
    808 char remote_host_name[MAXHOSTNAMELEN + 1];
    809 
    810 #ifndef	convex
    811 extern void telnet P((int, int));
    812 #else
    813 extern void telnet P((int, int, char *));
    814 #endif
    815 
    816 /*
    817  * Get a pty, scan input lines.
    818  */
    819 void
    820 doit(who)
    821 	struct sockaddr *who;
    822 {
    823 	char *host;
    824 	int error;
    825 	int level;
    826 	int ptynum;
    827 	char user_name[256];
    828 
    829 	/*
    830 	 * Find an available pty to use.
    831 	 */
    832 #ifndef	convex
    833 	pty = getpty(&ptynum);
    834 	if (pty < 0)
    835 		fatal(net, "All network ports in use");
    836 #else
    837 	for (;;) {
    838 		char *lp;
    839 		extern char *line;
    840 
    841 		if ((lp = getpty()) == NULL)
    842 			fatal(net, "Out of ptys");
    843 
    844 		if ((pty = open(lp, 2)) >= 0) {
    845 			strcpy(line,lp);
    846 			line[5] = 't';
    847 			break;
    848 		}
    849 	}
    850 #endif
    851 
    852 #if	defined(_SC_CRAY_SECURE_SYS)
    853 	/*
    854 	 *	set ttyp line security label
    855 	 */
    856 	if (secflag) {
    857 		char slave_dev[16];
    858 
    859 		sprintf(tty_dev, "/dev/pty/%03d", ptynum);
    860 		if (setdevs(tty_dev, &dv) < 0)
    861 		 	fatal(net, "cannot set pty security");
    862 		sprintf(slave_dev, "/dev/ttyp%03d", ptynum);
    863 		if (setdevs(slave_dev, &dv) < 0)
    864 		 	fatal(net, "cannot set tty security");
    865 	}
    866 #endif	/* _SC_CRAY_SECURE_SYS */
    867 
    868 	/* get name of connected client */
    869 	error = getnameinfo(who, who->sa_len, remote_host_name,
    870 			    sizeof(remote_host_name), NULL, 0, 0);
    871 
    872 	if (error) {
    873 		fatal(net, "Couldn't resolve your address into a host name.\r\n\
    874 	 Please contact your net administrator");
    875 #ifdef __GNUC__
    876 		host = NULL;	/* XXX gcc */
    877 #endif
    878 	}
    879 
    880 	remote_host_name[sizeof(remote_host_name)-1] = 0;
    881 	host = remote_host_name;
    882 
    883 	(void)gethostname(host_name, sizeof (host_name));
    884 	host_name[sizeof(host_name) - 1] = '\0';
    885 	hostname = host_name;
    886 
    887 #if	defined(AUTHENTICATION)
    888 	auth_encrypt_init(hostname, host, "TELNETD", 1);
    889 #endif
    890 
    891 	init_env();
    892 	/*
    893 	 * get terminal type.
    894 	 */
    895 	*user_name = 0;
    896 	level = getterminaltype(user_name);
    897 	setenv("TERM", terminaltype ? terminaltype : "network", 1);
    898 
    899 	/*
    900 	 * Start up the login process on the slave side of the terminal
    901 	 */
    902 #ifndef	convex
    903 	startslave(host, level, user_name);
    904 
    905 #if	defined(_SC_CRAY_SECURE_SYS)
    906 	if (secflag) {
    907 		if (setulvl(dv.dv_actlvl) < 0)
    908 			fatal(net,"cannot setulvl()");
    909 		if (setucmp(dv.dv_actcmp) < 0)
    910 			fatal(net, "cannot setucmp()");
    911 	}
    912 #endif	/* _SC_CRAY_SECURE_SYS */
    913 
    914 	telnet(net, pty);  /* begin server processing */
    915 #else
    916 	telnet(net, pty, host);
    917 #endif
    918 	/*NOTREACHED*/
    919 }  /* end of doit */
    920 
    921 #if	defined(CRAY2) && defined(UNICOS5) && defined(UNICOS50)
    922 	int
    923 Xterm_output(ibufp, obuf, icountp, ocount)
    924 	char **ibufp, *obuf;
    925 	int *icountp, ocount;
    926 {
    927 	int ret;
    928 	ret = term_output(*ibufp, obuf, *icountp, ocount);
    929 	*ibufp += *icountp;
    930 	*icountp = 0;
    931 	return(ret);
    932 }
    933 #define	term_output	Xterm_output
    934 #endif	/* defined(CRAY2) && defined(UNICOS5) && defined(UNICOS50) */
    935 
    936 /*
    937  * Main loop.  Select from pty and network, and
    938  * hand data to telnet receiver finite state machine.
    939  */
    940 	void
    941 #ifndef	convex
    942 telnet(f, p)
    943 #else
    944 telnet(f, p, host)
    945 #endif
    946 	int f, p;
    947 #ifdef convex
    948 	char *host;
    949 #endif
    950 {
    951 	int on = 1;
    952 #define	TABBUFSIZ	512
    953 	char	defent[TABBUFSIZ];
    954 	char	defstrs[TABBUFSIZ];
    955 #undef	TABBUFSIZ
    956 	char *HE;
    957 	char *HN;
    958 	char *IM;
    959 	int nfd;
    960 
    961 	/*
    962 	 * Initialize the slc mapping table.
    963 	 */
    964 	get_slc_defaults();
    965 
    966 	/*
    967 	 * Do some tests where it is desireable to wait for a response.
    968 	 * Rather than doing them slowly, one at a time, do them all
    969 	 * at once.
    970 	 */
    971 	if (my_state_is_wont(TELOPT_SGA))
    972 		send_will(TELOPT_SGA, 1);
    973 	/*
    974 	 * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
    975 	 * because 4.2 clients are unable to deal with TCP urgent data.
    976 	 *
    977 	 * To find out, we send out a "DO ECHO".  If the remote system
    978 	 * answers "WILL ECHO" it is probably a 4.2 client, and we note
    979 	 * that fact ("WILL ECHO" ==> that the client will echo what
    980 	 * WE, the server, sends it; it does NOT mean that the client will
    981 	 * echo the terminal input).
    982 	 */
    983 	send_do(TELOPT_ECHO, 1);
    984 
    985 #ifdef	LINEMODE
    986 	if (his_state_is_wont(TELOPT_LINEMODE)) {
    987 		/* Query the peer for linemode support by trying to negotiate
    988 		 * the linemode option.
    989 		 */
    990 		linemode = 0;
    991 		editmode = 0;
    992 		send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
    993 	}
    994 #endif	/* LINEMODE */
    995 
    996 	/*
    997 	 * Send along a couple of other options that we wish to negotiate.
    998 	 */
    999 	send_do(TELOPT_NAWS, 1);
   1000 	send_will(TELOPT_STATUS, 1);
   1001 	flowmode = 1;		/* default flow control state */
   1002 	restartany = -1;	/* uninitialized... */
   1003 	send_do(TELOPT_LFLOW, 1);
   1004 
   1005 	/*
   1006 	 * Spin, waiting for a response from the DO ECHO.  However,
   1007 	 * some REALLY DUMB telnets out there might not respond
   1008 	 * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
   1009 	 * telnets so far seem to respond with WONT for a DO that
   1010 	 * they don't understand...) because by the time we get the
   1011 	 * response, it will already have processed the DO ECHO.
   1012 	 * Kludge upon kludge.
   1013 	 */
   1014 	while (his_will_wont_is_changing(TELOPT_NAWS))
   1015 		ttloop();
   1016 
   1017 	/*
   1018 	 * But...
   1019 	 * The client might have sent a WILL NAWS as part of its
   1020 	 * startup code; if so, we'll be here before we get the
   1021 	 * response to the DO ECHO.  We'll make the assumption
   1022 	 * that any implementation that understands about NAWS
   1023 	 * is a modern enough implementation that it will respond
   1024 	 * to our DO ECHO request; hence we'll do another spin
   1025 	 * waiting for the ECHO option to settle down, which is
   1026 	 * what we wanted to do in the first place...
   1027 	 */
   1028 	if (his_want_state_is_will(TELOPT_ECHO) &&
   1029 	    his_state_is_will(TELOPT_NAWS)) {
   1030 		while (his_will_wont_is_changing(TELOPT_ECHO))
   1031 			ttloop();
   1032 	}
   1033 	/*
   1034 	 * On the off chance that the telnet client is broken and does not
   1035 	 * respond to the DO ECHO we sent, (after all, we did send the
   1036 	 * DO NAWS negotiation after the DO ECHO, and we won't get here
   1037 	 * until a response to the DO NAWS comes back) simulate the
   1038 	 * receipt of a will echo.  This will also send a WONT ECHO
   1039 	 * to the client, since we assume that the client failed to
   1040 	 * respond because it believes that it is already in DO ECHO
   1041 	 * mode, which we do not want.
   1042 	 */
   1043 	if (his_want_state_is_will(TELOPT_ECHO)) {
   1044 		DIAG(TD_OPTIONS,
   1045 			{sprintf(nfrontp, "td: simulating recv\r\n");
   1046 			 nfrontp += strlen(nfrontp);});
   1047 		willoption(TELOPT_ECHO);
   1048 	}
   1049 
   1050 	/*
   1051 	 * Finally, to clean things up, we turn on our echo.  This
   1052 	 * will break stupid 4.2 telnets out of local terminal echo.
   1053 	 */
   1054 
   1055 	if (my_state_is_wont(TELOPT_ECHO))
   1056 		send_will(TELOPT_ECHO, 1);
   1057 
   1058 #ifndef	STREAMSPTY
   1059 	/*
   1060 	 * Turn on packet mode
   1061 	 */
   1062 	(void) ioctl(p, TIOCPKT, (char *)&on);
   1063 #endif
   1064 
   1065 #if	defined(LINEMODE) && defined(KLUDGELINEMODE)
   1066 	/*
   1067 	 * Continuing line mode support.  If client does not support
   1068 	 * real linemode, attempt to negotiate kludge linemode by sending
   1069 	 * the do timing mark sequence.
   1070 	 */
   1071 	if (lmodetype < REAL_LINEMODE)
   1072 		send_do(TELOPT_TM, 1);
   1073 #endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */
   1074 
   1075 	/*
   1076 	 * Call telrcv() once to pick up anything received during
   1077 	 * terminal type negotiation, 4.2/4.3 determination, and
   1078 	 * linemode negotiation.
   1079 	 */
   1080 	telrcv();
   1081 
   1082 	(void) ioctl(f, FIONBIO, (char *)&on);
   1083 	(void) ioctl(p, FIONBIO, (char *)&on);
   1084 #if	defined(CRAY2) && defined(UNICOS5)
   1085 	init_termdriver(f, p, interrupt, sendbrk);
   1086 #endif
   1087 
   1088 #if	defined(SO_OOBINLINE)
   1089 	(void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
   1090 				(char *)&on, sizeof on);
   1091 #endif	/* defined(SO_OOBINLINE) */
   1092 
   1093 #ifdef	SIGTSTP
   1094 	(void) signal(SIGTSTP, SIG_IGN);
   1095 #endif
   1096 #ifdef	SIGTTOU
   1097 	/*
   1098 	 * Ignoring SIGTTOU keeps the kernel from blocking us
   1099 	 * in ttioct() in /sys/tty.c.
   1100 	 */
   1101 	(void) signal(SIGTTOU, SIG_IGN);
   1102 #endif
   1103 
   1104 	(void) signal(SIGCHLD, cleanup);
   1105 
   1106 #if	defined(CRAY2) && defined(UNICOS5)
   1107 	/*
   1108 	 * Cray-2 will send a signal when pty modes are changed by slave
   1109 	 * side.  Set up signal handler now.
   1110 	 */
   1111 	if ((int)signal(SIGUSR1, termstat) < 0)
   1112 		perror("signal");
   1113 	else if (ioctl(p, TCSIGME, (char *)SIGUSR1) < 0)
   1114 		perror("ioctl:TCSIGME");
   1115 	/*
   1116 	 * Make processing loop check terminal characteristics early on.
   1117 	 */
   1118 	termstat();
   1119 #endif
   1120 
   1121 #ifdef  TIOCNOTTY
   1122 	{
   1123 		register int t;
   1124 		t = open(_PATH_TTY, O_RDWR);
   1125 		if (t >= 0) {
   1126 			(void) ioctl(t, TIOCNOTTY, (char *)0);
   1127 			(void) close(t);
   1128 		}
   1129 	}
   1130 #endif
   1131 
   1132 #if	defined(CRAY) && defined(NEWINIT) && defined(TIOCSCTTY)
   1133 	(void) setsid();
   1134 	ioctl(p, TIOCSCTTY, 0);
   1135 #endif
   1136 
   1137 	/*
   1138 	 * Show banner that getty never gave.
   1139 	 *
   1140 	 * We put the banner in the pty input buffer.  This way, it
   1141 	 * gets carriage return null processing, etc., just like all
   1142 	 * other pty --> client data.
   1143 	 */
   1144 
   1145 #if	!defined(CRAY) || !defined(NEWINIT)
   1146 	if (getenv("USER"))
   1147 		hostinfo = 0;
   1148 #endif
   1149 
   1150 	if (getent(defent, gettyname) == 1) {
   1151 		char *cp=defstrs;
   1152 
   1153 		HE = getstr("he", &cp);
   1154 		HN = getstr("hn", &cp);
   1155 		IM = getstr("im", &cp);
   1156 		if (HN && *HN)
   1157 			(void) strcpy(host_name, HN);
   1158 		if (IM == 0)
   1159 			IM = "";
   1160 	} else {
   1161 		IM = DEFAULT_IM;
   1162 		HE = 0;
   1163 	}
   1164 	edithost(HE, host_name);
   1165 	if (hostinfo && *IM)
   1166 		putf(IM, ptyibuf2);
   1167 
   1168 	if (pcc)
   1169 		(void) strncat(ptyibuf2, ptyip, pcc+1);
   1170 	ptyip = ptyibuf2;
   1171 	pcc = strlen(ptyip);
   1172 #ifdef	LINEMODE
   1173 	/*
   1174 	 * Last check to make sure all our states are correct.
   1175 	 */
   1176 	init_termbuf();
   1177 	localstat();
   1178 #endif	/* LINEMODE */
   1179 
   1180 	DIAG(TD_REPORT,
   1181 		{sprintf(nfrontp, "td: Entering processing loop\r\n");
   1182 		 nfrontp += strlen(nfrontp);});
   1183 
   1184 #ifdef	convex
   1185 	startslave(host);
   1186 #endif
   1187 
   1188 	nfd = ((f > p) ? f : p) + 1;
   1189 	for (;;) {
   1190 		fd_set ibits, obits, xbits;
   1191 		register int c;
   1192 
   1193 		if (ncc < 0 && pcc < 0)
   1194 			break;
   1195 
   1196 #if	defined(CRAY2) && defined(UNICOS5)
   1197 		if (needtermstat)
   1198 			_termstat();
   1199 #endif	/* defined(CRAY2) && defined(UNICOS5) */
   1200 		FD_ZERO(&ibits);
   1201 		FD_ZERO(&obits);
   1202 		FD_ZERO(&xbits);
   1203 		/*
   1204 		 * Never look for input if there's still
   1205 		 * stuff in the corresponding output buffer
   1206 		 */
   1207 		if (nfrontp - nbackp || pcc > 0) {
   1208 			FD_SET(f, &obits);
   1209 		} else {
   1210 			FD_SET(p, &ibits);
   1211 		}
   1212 		if (pfrontp - pbackp || ncc > 0) {
   1213 			FD_SET(p, &obits);
   1214 		} else {
   1215 			FD_SET(f, &ibits);
   1216 		}
   1217 		if (!SYNCHing) {
   1218 			FD_SET(f, &xbits);
   1219 		}
   1220 		if ((c = select(nfd, &ibits, &obits, &xbits,
   1221 						(struct timeval *)0)) < 1) {
   1222 			if (c == -1) {
   1223 				if (errno == EINTR) {
   1224 					continue;
   1225 				}
   1226 			}
   1227 			sleep(5);
   1228 			continue;
   1229 		}
   1230 
   1231 		/*
   1232 		 * Any urgent data?
   1233 		 */
   1234 		if (FD_ISSET(net, &xbits)) {
   1235 		    SYNCHing = 1;
   1236 		}
   1237 
   1238 		/*
   1239 		 * Something to read from the network...
   1240 		 */
   1241 		if (FD_ISSET(net, &ibits)) {
   1242 #if	!defined(SO_OOBINLINE)
   1243 			/*
   1244 			 * In 4.2 (and 4.3 beta) systems, the
   1245 			 * OOB indication and data handling in the kernel
   1246 			 * is such that if two separate TCP Urgent requests
   1247 			 * come in, one byte of TCP data will be overlaid.
   1248 			 * This is fatal for Telnet, but we try to live
   1249 			 * with it.
   1250 			 *
   1251 			 * In addition, in 4.2 (and...), a special protocol
   1252 			 * is needed to pick up the TCP Urgent data in
   1253 			 * the correct sequence.
   1254 			 *
   1255 			 * What we do is:  if we think we are in urgent
   1256 			 * mode, we look to see if we are "at the mark".
   1257 			 * If we are, we do an OOB receive.  If we run
   1258 			 * this twice, we will do the OOB receive twice,
   1259 			 * but the second will fail, since the second
   1260 			 * time we were "at the mark", but there wasn't
   1261 			 * any data there (the kernel doesn't reset
   1262 			 * "at the mark" until we do a normal read).
   1263 			 * Once we've read the OOB data, we go ahead
   1264 			 * and do normal reads.
   1265 			 *
   1266 			 * There is also another problem, which is that
   1267 			 * since the OOB byte we read doesn't put us
   1268 			 * out of OOB state, and since that byte is most
   1269 			 * likely the TELNET DM (data mark), we would
   1270 			 * stay in the TELNET SYNCH (SYNCHing) state.
   1271 			 * So, clocks to the rescue.  If we've "just"
   1272 			 * received a DM, then we test for the
   1273 			 * presence of OOB data when the receive OOB
   1274 			 * fails (and AFTER we did the normal mode read
   1275 			 * to clear "at the mark").
   1276 			 */
   1277 		    if (SYNCHing) {
   1278 			int atmark;
   1279 
   1280 			(void) ioctl(net, SIOCATMARK, (char *)&atmark);
   1281 			if (atmark) {
   1282 			    ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
   1283 			    if ((ncc == -1) && (errno == EINVAL)) {
   1284 				ncc = read(net, netibuf, sizeof (netibuf));
   1285 				if (sequenceIs(didnetreceive, gotDM)) {
   1286 				    SYNCHing = stilloob(net);
   1287 				}
   1288 			    }
   1289 			} else {
   1290 			    ncc = read(net, netibuf, sizeof (netibuf));
   1291 			}
   1292 		    } else {
   1293 			ncc = read(net, netibuf, sizeof (netibuf));
   1294 		    }
   1295 		    settimer(didnetreceive);
   1296 #else	/* !defined(SO_OOBINLINE)) */
   1297 		    ncc = read(net, netibuf, sizeof (netibuf));
   1298 #endif	/* !defined(SO_OOBINLINE)) */
   1299 		    if (ncc < 0 && errno == EWOULDBLOCK)
   1300 			ncc = 0;
   1301 		    else {
   1302 			if (ncc <= 0) {
   1303 			    break;
   1304 			}
   1305 			netip = netibuf;
   1306 		    }
   1307 		    DIAG((TD_REPORT | TD_NETDATA),
   1308 			    {sprintf(nfrontp, "td: netread %d chars\r\n", ncc);
   1309 			     nfrontp += strlen(nfrontp);});
   1310 		    DIAG(TD_NETDATA, printdata("nd", netip, ncc));
   1311 		}
   1312 
   1313 		/*
   1314 		 * Something to read from the pty...
   1315 		 */
   1316 		if (FD_ISSET(p, &ibits)) {
   1317 #ifndef	STREAMSPTY
   1318 			pcc = read(p, ptyibuf, BUFSIZ);
   1319 #else
   1320 			pcc = readstream(p, ptyibuf, BUFSIZ);
   1321 #endif
   1322 			/*
   1323 			 * On some systems, if we try to read something
   1324 			 * off the master side before the slave side is
   1325 			 * opened, we get EIO.
   1326 			 */
   1327 			if (pcc < 0 && (errno == EWOULDBLOCK ||
   1328 #ifdef	EAGAIN
   1329 					errno == EAGAIN ||
   1330 #endif
   1331 					errno == EIO)) {
   1332 				pcc = 0;
   1333 			} else {
   1334 				if (pcc <= 0)
   1335 					break;
   1336 #if	!defined(CRAY2) || !defined(UNICOS5)
   1337 #ifdef	LINEMODE
   1338 				/*
   1339 				 * If ioctl from pty, pass it through net
   1340 				 */
   1341 				if (ptyibuf[0] & TIOCPKT_IOCTL) {
   1342 					copy_termbuf(ptyibuf+1, pcc-1);
   1343 					localstat();
   1344 					pcc = 1;
   1345 				}
   1346 #endif	/* LINEMODE */
   1347 				if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
   1348 					netclear();	/* clear buffer back */
   1349 #ifndef	NO_URGENT
   1350 					/*
   1351 					 * There are client telnets on some
   1352 					 * operating systems get screwed up
   1353 					 * royally if we send them urgent
   1354 					 * mode data.
   1355 					 */
   1356 					*nfrontp++ = IAC;
   1357 					*nfrontp++ = DM;
   1358 					neturg = nfrontp-1; /* off by one XXX */
   1359 					DIAG(TD_OPTIONS,
   1360 					    printoption("td: send IAC", DM));
   1361 
   1362 #endif
   1363 				}
   1364 				if (his_state_is_will(TELOPT_LFLOW) &&
   1365 				    (ptyibuf[0] &
   1366 				     (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
   1367 					int newflow =
   1368 					    ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
   1369 					if (newflow != flowmode) {
   1370 						flowmode = newflow;
   1371 						(void) sprintf(nfrontp,
   1372 							"%c%c%c%c%c%c",
   1373 							IAC, SB, TELOPT_LFLOW,
   1374 							flowmode ? LFLOW_ON
   1375 								 : LFLOW_OFF,
   1376 							IAC, SE);
   1377 						nfrontp += 6;
   1378 						DIAG(TD_OPTIONS, printsub('>',
   1379 						    (unsigned char *)nfrontp-4,
   1380 						    4););
   1381 					}
   1382 				}
   1383 				pcc--;
   1384 				ptyip = ptyibuf+1;
   1385 #else	/* defined(CRAY2) && defined(UNICOS5) */
   1386 				if (!uselinemode) {
   1387 					unpcc = pcc;
   1388 					unptyip = ptyibuf;
   1389 					pcc = term_output(&unptyip, ptyibuf2,
   1390 								&unpcc, BUFSIZ);
   1391 					ptyip = ptyibuf2;
   1392 				} else
   1393 					ptyip = ptyibuf;
   1394 #endif	/* defined(CRAY2) && defined(UNICOS5) */
   1395 			}
   1396 		}
   1397 
   1398 		while (pcc > 0) {
   1399 			if ((&netobuf[BUFSIZ] - nfrontp) < 2)
   1400 				break;
   1401 			c = *ptyip++ & 0377, pcc--;
   1402 			if (c == IAC)
   1403 				*nfrontp++ = c;
   1404 #if	defined(CRAY2) && defined(UNICOS5)
   1405 			else if (c == '\n' &&
   1406 				     my_state_is_wont(TELOPT_BINARY) && newmap)
   1407 				*nfrontp++ = '\r';
   1408 #endif	/* defined(CRAY2) && defined(UNICOS5) */
   1409 			*nfrontp++ = c;
   1410 			if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
   1411 				if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
   1412 					*nfrontp++ = *ptyip++ & 0377;
   1413 					pcc--;
   1414 				} else
   1415 					*nfrontp++ = '\0';
   1416 			}
   1417 		}
   1418 #if	defined(CRAY2) && defined(UNICOS5)
   1419 		/*
   1420 		 * If chars were left over from the terminal driver,
   1421 		 * note their existence.
   1422 		 */
   1423 		if (!uselinemode && unpcc) {
   1424 			pcc = unpcc;
   1425 			unpcc = 0;
   1426 			ptyip = unptyip;
   1427 		}
   1428 #endif	/* defined(CRAY2) && defined(UNICOS5) */
   1429 
   1430 		if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
   1431 			netflush();
   1432 		if (ncc > 0)
   1433 			telrcv();
   1434 		if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
   1435 			ptyflush();
   1436 	}
   1437 	cleanup(0);
   1438 }  /* end of telnet */
   1439 
   1440 #ifndef	TCSIG
   1441 # ifdef	TIOCSIG
   1442 #  define TCSIG TIOCSIG
   1443 # endif
   1444 #endif
   1445 
   1446 #ifdef	STREAMSPTY
   1447 
   1448 int flowison = -1;  /* current state of flow: -1 is unknown */
   1449 
   1450 int readstream(p, ibuf, bufsize)
   1451 	int p;
   1452 	char *ibuf;
   1453 	int bufsize;
   1454 {
   1455 	int flags = 0;
   1456 	int ret = 0;
   1457 	struct termios *tsp;
   1458 	struct termio *tp;
   1459 	struct iocblk *ip;
   1460 	char vstop, vstart;
   1461 	int ixon;
   1462 	int newflow;
   1463 
   1464 	strbufc.maxlen = BUFSIZ;
   1465 	strbufc.buf = (char *)ctlbuf;
   1466 	strbufd.maxlen = bufsize-1;
   1467 	strbufd.len = 0;
   1468 	strbufd.buf = ibuf+1;
   1469 	ibuf[0] = 0;
   1470 
   1471 	ret = getmsg(p, &strbufc, &strbufd, &flags);
   1472 	if (ret < 0)  /* error of some sort -- probably EAGAIN */
   1473 		return(-1);
   1474 
   1475 	if (strbufc.len <= 0 || ctlbuf[0] == M_DATA) {
   1476 		/* data message */
   1477 		if (strbufd.len > 0) {			/* real data */
   1478 			return(strbufd.len + 1);	/* count header char */
   1479 		} else {
   1480 			/* nothing there */
   1481 			errno = EAGAIN;
   1482 			return(-1);
   1483 		}
   1484 	}
   1485 
   1486 	/*
   1487 	 * It's a control message.  Return 1, to look at the flag we set
   1488 	 */
   1489 
   1490 	switch (ctlbuf[0]) {
   1491 	case M_FLUSH:
   1492 		if (ibuf[1] & FLUSHW)
   1493 			ibuf[0] = TIOCPKT_FLUSHWRITE;
   1494 		return(1);
   1495 
   1496 	case M_IOCTL:
   1497 		ip = (struct iocblk *) (ibuf+1);
   1498 
   1499 		switch (ip->ioc_cmd) {
   1500 		case TCSETS:
   1501 		case TCSETSW:
   1502 		case TCSETSF:
   1503 			tsp = (struct termios *)
   1504 					(ibuf+1 + sizeof(struct iocblk));
   1505 			vstop = tsp->c_cc[VSTOP];
   1506 			vstart = tsp->c_cc[VSTART];
   1507 			ixon = tsp->c_iflag & IXON;
   1508 			break;
   1509 		case TCSETA:
   1510 		case TCSETAW:
   1511 		case TCSETAF:
   1512 			tp = (struct termio *) (ibuf+1 + sizeof(struct iocblk));
   1513 			vstop = tp->c_cc[VSTOP];
   1514 			vstart = tp->c_cc[VSTART];
   1515 			ixon = tp->c_iflag & IXON;
   1516 			break;
   1517 		default:
   1518 			errno = EAGAIN;
   1519 			return(-1);
   1520 		}
   1521 
   1522 		newflow =  (ixon && (vstart == 021) && (vstop == 023)) ? 1 : 0;
   1523 		if (newflow != flowison) {  /* it's a change */
   1524 			flowison = newflow;
   1525 			ibuf[0] = newflow ? TIOCPKT_DOSTOP : TIOCPKT_NOSTOP;
   1526 			return(1);
   1527 		}
   1528 	}
   1529 
   1530 	/* nothing worth doing anything about */
   1531 	errno = EAGAIN;
   1532 	return(-1);
   1533 }
   1534 #endif /* STREAMSPTY */
   1535 
   1536 /*
   1537  * Send interrupt to process on other side of pty.
   1538  * If it is in raw mode, just write NULL;
   1539  * otherwise, write intr char.
   1540  */
   1541 	void
   1542 interrupt()
   1543 {
   1544 	ptyflush();	/* half-hearted */
   1545 
   1546 #if defined(STREAMSPTY) && defined(TIOCSIGNAL)
   1547 	/* Streams PTY style ioctl to post a signal */
   1548 	{
   1549 		int sig = SIGINT;
   1550 		(void) ioctl(pty, TIOCSIGNAL, &sig);
   1551 		(void) ioctl(pty, I_FLUSH, FLUSHR);
   1552 	}
   1553 #else
   1554 #ifdef	TCSIG
   1555 	(void) ioctl(pty, TCSIG, (char *)SIGINT);
   1556 #else	/* TCSIG */
   1557 	init_termbuf();
   1558 	*pfrontp++ = slctab[SLC_IP].sptr ?
   1559 			(unsigned char)*slctab[SLC_IP].sptr : '\177';
   1560 #endif	/* TCSIG */
   1561 #endif
   1562 }
   1563 
   1564 /*
   1565  * Send quit to process on other side of pty.
   1566  * If it is in raw mode, just write NULL;
   1567  * otherwise, write quit char.
   1568  */
   1569 	void
   1570 sendbrk()
   1571 {
   1572 	ptyflush();	/* half-hearted */
   1573 #ifdef	TCSIG
   1574 	(void) ioctl(pty, TCSIG, (char *)SIGQUIT);
   1575 #else	/* TCSIG */
   1576 	init_termbuf();
   1577 	*pfrontp++ = slctab[SLC_ABORT].sptr ?
   1578 			(unsigned char)*slctab[SLC_ABORT].sptr : '\034';
   1579 #endif	/* TCSIG */
   1580 }
   1581 
   1582 	void
   1583 sendsusp()
   1584 {
   1585 #ifdef	SIGTSTP
   1586 	ptyflush();	/* half-hearted */
   1587 # ifdef	TCSIG
   1588 	(void) ioctl(pty, TCSIG, (char *)SIGTSTP);
   1589 # else	/* TCSIG */
   1590 	*pfrontp++ = slctab[SLC_SUSP].sptr ?
   1591 			(unsigned char)*slctab[SLC_SUSP].sptr : '\032';
   1592 # endif	/* TCSIG */
   1593 #endif	/* SIGTSTP */
   1594 }
   1595 
   1596 /*
   1597  * When we get an AYT, if ^T is enabled, use that.  Otherwise,
   1598  * just send back "[Yes]".
   1599  */
   1600 	void
   1601 recv_ayt()
   1602 {
   1603 #if	defined(SIGINFO) && defined(TCSIG)
   1604 	if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
   1605 		(void) ioctl(pty, TCSIG, (char *)SIGINFO);
   1606 		return;
   1607 	}
   1608 #endif
   1609 	(void) strcpy(nfrontp, "\r\n[Yes]\r\n");
   1610 	nfrontp += 9;
   1611 }
   1612 
   1613 	void
   1614 doeof()
   1615 {
   1616 	init_termbuf();
   1617 
   1618 #if	defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
   1619 	if (!tty_isediting()) {
   1620 		extern char oldeofc;
   1621 		*pfrontp++ = oldeofc;
   1622 		return;
   1623 	}
   1624 #endif
   1625 	*pfrontp++ = slctab[SLC_EOF].sptr ?
   1626 			(unsigned char)*slctab[SLC_EOF].sptr : '\004';
   1627 }
   1628