appl/telnet/telnetd/telnetd.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "telnetd.h"
  35
  36 RCSID("$Id$");
  37
  38 #ifdef _SC_CRAY_SECURE_SYS
  39 #include <sys/sysv.h>
  40 #include <sys/secdev.h>
  41 #include <sys/secparm.h>
  42 #include <sys/usrv.h>
  43 int     secflag;
  44 char    tty_dev[16];
  45 struct  secdev dv;
  46 struct  sysv sysv;
  47 struct  socksec ss;
  48 #endif  /* _SC_CRAY_SECURE_SYS */
  49
  50 #ifdef AUTHENTICATION
  51 int     auth_level = 0;
  52 #endif
  53
  54 #ifdef KRB5
  55 #define Authenticator k5_Authenticator
  56 #include <krb5.h>
  57 #undef Authenticator
  58 #endif
  59
  60 extern  int utmp_len;
  61 int     registerd_host_only = 0;
  62 #ifdef ENCRYPTION
  63 int     require_encryption = 0;
  64 #endif
  65
  66 #ifdef STREAMSPTY
  67
  68 #ifdef _AIX
  69 #include <sys/termio.h>
  70 #endif
  71 # ifdef HAVE_SYS_STRTTY_H
  72 # include <sys/strtty.h>
  73 # endif
  74 # ifdef HAVE_SYS_STR_TTY_H
  75 # include <sys/str_tty.h>
  76 # endif
  77 /* make sure we don't get the bsd version */
  78 /* what is this here for? solaris? /joda */
  79 # ifdef HAVE_SYS_TTY_H
  80 # include "/usr/include/sys/tty.h"
  81 # endif
  82 # ifdef HAVE_SYS_PTYVAR_H
  83 # include <sys/ptyvar.h>
  84 # endif
  85
  86 /*
  87  * Because of the way ptyibuf is used with streams messages, we need
  88  * ptyibuf+1 to be on a full-word boundary.  The following wierdness
  89  * is simply to make that happen.
  90  */
  91 long    ptyibufbuf[BUFSIZ/sizeof(long)+1];
  92 char    *ptyibuf = ((char *)&ptyibufbuf[1])-1;
  93 char    *ptyip = ((char *)&ptyibufbuf[1])-1;
  94 char    ptyibuf2[BUFSIZ];
  95 unsigned char ctlbuf[BUFSIZ];
  96 struct  strbuf strbufc, strbufd;
  97
  98 int readstream(int, char*, int);
  99
 100 #else   /* ! STREAMPTY */
 101
 102 /*
 103  * I/O data buffers,
 104  * pointers, and counters.
 105  */
 106 char    ptyibuf[BUFSIZ], *ptyip = ptyibuf;
 107 char    ptyibuf2[BUFSIZ];
 108
 109 #endif /* ! STREAMPTY */
 110
 111 int     hostinfo = 1;                   /* do we print login banner? */
 112
 113 #ifdef  _CRAY
 114 extern int      newmap; /* nonzero if \n maps to ^M^J */
 115 int     lowpty = 0, highpty;    /* low, high pty numbers */
 116 #endif /* CRAY */
 117
 118 int debug = 0;
 119 int keepalive = 1;
 120 char *progname;
 121
 122 static void usage (int error_code);
 123
 124 /*
 125  * The string to pass to getopt().  We do it this way so
 126  * that only the actual options that we support will be
 127  * passed off to getopt().
 128  */
 129 char valid_opts[] = "Bd:hklnS:u:UL:y"
 130 #ifdef AUTHENTICATION
 131                     "a:X:z"
 132 #endif
 133 #ifdef ENCRYPTION
 134                      "e"
 135 #endif
 136 #ifdef DIAGNOSTICS
 137                     "D:"
 138 #endif
 139 #ifdef _CRAY
 140                     "r:"
 141 #endif
 142                     ;
 143
 144 static void doit(struct sockaddr*, int);
 145
 146 int
 147 main(int argc, char **argv)
 148 {
 149     struct sockaddr_storage __ss;
 150     struct sockaddr *sa = (struct sockaddr *)&__ss;
 151     int on = 1;
 152     socklen_t sa_size;
 153     int ch;
 154 #if     defined(IPPROTO_IP) && defined(IP_TOS)
 155     int tos = -1;
 156 #endif
 157     pfrontp = pbackp = ptyobuf;
 158     netip = netibuf;
 159     nfrontp = nbackp = netobuf;
 160
 161     setprogname(argv[0]);
 162
 163     progname = *argv;
 164 #ifdef ENCRYPTION
 165     nclearto = 0;
 166 #endif
 167
 168 #ifdef _CRAY
 169     /*
 170      * Get number of pty's before trying to process options,
 171      * which may include changing pty range.
 172      */
 173     highpty = getnpty();
 174 #endif /* CRAY */
 175
 176     if (argc == 2 && strcmp(argv[1], "--version") == 0) {
 177         print_version(NULL);
 178         exit(0);
 179     }
 180     if (argc == 2 && strcmp(argv[1], "--help") == 0)
 181         usage(0);
 182
 183     while ((ch = getopt(argc, argv, valid_opts)) != -1) {
 184         switch(ch) {
 185
 186 #ifdef  AUTHENTICATION
 187         case 'a':
 188             /*
 189              * Check for required authentication level
 190              */
 191             if (strcmp(optarg, "debug") == 0) {
 192                 auth_debug_mode = 1;
 193             } else if (strcasecmp(optarg, "none") == 0) {
 194                 auth_level = 0;
 195             } else if (strcasecmp(optarg, "otp") == 0) {
 196                 auth_level = 0;
 197                 require_otp = 1;
 198             } else if (strcasecmp(optarg, "other") == 0) {
 199                 auth_level = AUTH_OTHER;
 200             } else if (strcasecmp(optarg, "user") == 0) {
 201                 auth_level = AUTH_USER;
 202             } else if (strcasecmp(optarg, "valid") == 0) {
 203                 auth_level = AUTH_VALID;
 204             } else if (strcasecmp(optarg, "off") == 0) {
 205                 /*
 206                  * This hack turns off authentication
 207                  */
 208                 auth_level = -1;
 209             } else {
 210                 fprintf(stderr,
 211                         "telnetd: unknown authorization level for -a\n");
 212             }
 213             break;
 214 #endif  /* AUTHENTICATION */
 215
 216         case 'B': /* BFTP mode is not supported any more */
 217             break;
 218         case 'd':
 219             if (strcmp(optarg, "ebug") == 0) {
 220                 debug++;
 221                 break;
 222             }
 223             usage(1);
 224             /* NOTREACHED */
 225             break;
 226
 227 #ifdef DIAGNOSTICS
 228         case 'D':
 229             /*
 230              * Check for desired diagnostics capabilities.
 231              */
 232             if (!strcmp(optarg, "report")) {
 233                 diagnostic |= TD_REPORT|TD_OPTIONS;
 234             } else if (!strcmp(optarg, "exercise")) {
 235                 diagnostic |= TD_EXERCISE;
 236             } else if (!strcmp(optarg, "netdata")) {
 237                 diagnostic |= TD_NETDATA;
 238             } else if (!strcmp(optarg, "ptydata")) {
 239                 diagnostic |= TD_PTYDATA;
 240             } else if (!strcmp(optarg, "options")) {
 241                 diagnostic |= TD_OPTIONS;
 242             } else {
 243                 usage(1);
 244                 /* NOT REACHED */
 245             }
 246             break;
 247 #endif /* DIAGNOSTICS */
 248
 249 #ifdef ENCRYPTION
 250         case 'e':
 251             require_encryption = 1;
 252             break;
 253 #endif
 254
 255         case 'h':
 256             hostinfo = 0;
 257             break;
 258
 259         case 'k': /* Linemode is not supported any more */
 260         case 'l':
 261             break;
 262
 263         case 'n':
 264             keepalive = 0;
 265             break;
 266
 267 #ifdef _CRAY
 268         case 'r':
 269             {
 270                 char *strchr();
 271                 char *c;
 272
 273                 /*
 274                  * Allow the specification of alterations
 275                  * to the pty search range.  It is legal to
 276                  * specify only one, and not change the
 277                  * other from its default.
 278                  */
 279                 c = strchr(optarg, '-');
 280                 if (c) {
 281                     *c++ = '\0';
 282                     highpty = atoi(c);
 283                 }
 284                 if (*optarg != '\0')
 285                     lowpty = atoi(optarg);
 286                 if ((lowpty > highpty) || (lowpty < 0) ||
 287                     (highpty > 32767)) {
 288                     usage(1);
 289                     /* NOT REACHED */
 290                 }
 291                 break;
 292             }
 293 #endif  /* CRAY */
 294
 295         case 'S':
 296 #ifdef  HAVE_PARSETOS
 297             if ((tos = parsetos(optarg, "tcp")) < 0)
 298                 fprintf(stderr, "%s%s%s\n",
 299                         "telnetd: Bad TOS argument '", optarg,
 300                         "'; will try to use default TOS");
 301 #else
 302             fprintf(stderr, "%s%s\n", "TOS option unavailable; ",
 303                     "-S flag not supported\n");
 304 #endif
 305             break;
 306
 307         case 'u': {
 308             char *eptr;
 309
 310             utmp_len = strtol(optarg, &eptr, 0);
 311             if (optarg == eptr)
 312                 fprintf(stderr, "telnetd: unknown utmp len (%s)\n", optarg);
 313             break;
 314         }
 315
 316         case 'U':
 317             registerd_host_only = 1;
 318             break;
 319
 320 #ifdef  AUTHENTICATION
 321         case 'X':
 322             /*
 323              * Check for invalid authentication types
 324              */
 325             auth_disable_name(optarg);
 326             break;
 327 #endif
 328         case 'y':
 329             no_warn = 1;
 330             break;
 331 #ifdef AUTHENTICATION
 332         case 'z':
 333             log_unauth = 1;
 334             break;
 335
 336 #endif  /* AUTHENTICATION */
 337
 338         case 'L':
 339             new_login = optarg;
 340             break;
 341
 342         default:
 343             fprintf(stderr, "telnetd: %c: unknown option\n", ch);
 344             /* FALLTHROUGH */
 345         case '?':
 346             usage(0);
 347             /* NOTREACHED */
 348         }
 349     }
 350
 351     argc -= optind;
 352     argv += optind;
 353
 354     if (debug) {
 355         int port = 0;
 356         struct servent *sp;
 357
 358         if (argc > 1) {
 359             usage (1);
 360         } else if (argc == 1) {
 361             sp = roken_getservbyname (*argv, "tcp");
 362             if (sp)
 363                 port = sp->s_port;
 364             else
 365                 port = htons(atoi(*argv));
 366         } else {
 367 #ifdef KRB5
 368             port = krb5_getportbyname (NULL, "telnet", "tcp", 23);
 369 #else
 370             port = k_getportbyname("telnet", "tcp", htons(23));
 371 #endif
 372         }
 373         mini_inetd (port);
 374     } else if (argc > 0) {
 375         usage(1);
 376         /* NOT REACHED */
 377     }
 378
 379 #ifdef _SC_CRAY_SECURE_SYS
 380     secflag = sysconf(_SC_CRAY_SECURE_SYS);
 381
 382     /*
 383      *  Get socket's security label
 384      */
 385     if (secflag)  {
 386         socklen_t szss = sizeof(ss);
 387         int sock_multi;
 388         socklen_t szi = sizeof(int);
 389
 390         memset(&dv, 0, sizeof(dv));
 391
 392         if (getsysv(&sysv, sizeof(struct sysv)) != 0)
 393             fatalperror(net, "getsysv");
 394
 395         /*
 396          *      Get socket security label and set device values
 397          *         {security label to be set on ttyp device}
 398          */
 399 #ifdef SO_SEC_MULTI                     /* 8.0 code */
 400         if ((getsockopt(0, SOL_SOCKET, SO_SECURITY,
 401                         (void *)&ss, &szss) < 0) ||
 402             (getsockopt(0, SOL_SOCKET, SO_SEC_MULTI,
 403                         (void *)&sock_multi, &szi) < 0))
 404             fatalperror(net, "getsockopt");
 405         else {
 406             dv.dv_actlvl = ss.ss_actlabel.lt_level;
 407             dv.dv_actcmp = ss.ss_actlabel.lt_compart;
 408             if (!sock_multi) {
 409                 dv.dv_minlvl = dv.dv_maxlvl = dv.dv_actlvl;
 410                 dv.dv_valcmp = dv.dv_actcmp;
 411             } else {
 412                 dv.dv_minlvl = ss.ss_minlabel.lt_level;
 413                 dv.dv_maxlvl = ss.ss_maxlabel.lt_level;
 414                 dv.dv_valcmp = ss.ss_maxlabel.lt_compart;
 415             }
 416             dv.dv_devflg = 0;
 417         }
 418 #else /* SO_SEC_MULTI */                /* 7.0 code */
 419         if (getsockopt(0, SOL_SOCKET, SO_SECURITY,
 420                        (void *)&ss, &szss) >= 0) {
 421             dv.dv_actlvl = ss.ss_slevel;
 422             dv.dv_actcmp = ss.ss_compart;
 423             dv.dv_minlvl = ss.ss_minlvl;
 424             dv.dv_maxlvl = ss.ss_maxlvl;
 425             dv.dv_valcmp = ss.ss_maxcmp;
 426         }
 427 #endif /* SO_SEC_MULTI */
 428     }
 429 #endif  /* _SC_CRAY_SECURE_SYS */
 430
 431     roken_openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
 432     sa_size = sizeof (__ss);
 433     if (getpeername(STDIN_FILENO, sa, &sa_size) < 0) {
 434         fprintf(stderr, "%s: ", progname);
 435         perror("getpeername");
 436         _exit(1);
 437     }
 438     if (keepalive &&
 439         setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE,
 440                    (void *)&on, sizeof (on)) < 0) {
 441         syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
 442     }
 443
 444 #if     defined(IPPROTO_IP) && defined(IP_TOS) && defined(HAVE_SETSOCKOPT)
 445     {
 446 # ifdef HAVE_GETTOSBYNAME
 447         struct tosent *tp;
 448         if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
 449             tos = tp->t_tos;
 450 # endif
 451         if (tos < 0)
 452             tos = 020;  /* Low Delay bit */
 453         if (tos
 454             && sa->sa_family == AF_INET
 455             && (setsockopt(STDIN_FILENO, IPPROTO_IP, IP_TOS,
 456                            (void *)&tos, sizeof(tos)) < 0)
 457             && (errno != ENOPROTOOPT) )
 458             syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
 459     }
 460 #endif  /* defined(IPPROTO_IP) && defined(IP_TOS) */
 461     net = STDIN_FILENO;
 462     doit(sa, sa_size);
 463     /* NOTREACHED */
 464     return 0;
 465 }  /* end of main */
 466
 467 static void
 468 usage(int exit_code)
 469 {
 470     fprintf(stderr, "Usage: telnetd");
 471     fprintf(stderr, " [--help]");
 472     fprintf(stderr, " [--version]");
 473 #ifdef  AUTHENTICATION
 474     fprintf(stderr, " [-a (debug|other|otp|user|valid|off|none)]\n\t");
 475 #endif
 476     fprintf(stderr, " [-debug]");
 477 #ifdef DIAGNOSTICS
 478     fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
 479 #endif
 480 #ifdef  AUTHENTICATION
 481     fprintf(stderr, " [-edebug]");
 482 #endif
 483     fprintf(stderr, " [-h]");
 484     fprintf(stderr, " [-L login]");
 485     fprintf(stderr, " [-n]");
 486 #ifdef  _CRAY
 487     fprintf(stderr, " [-r[lowpty]-[highpty]]");
 488 #endif
 489     fprintf(stderr, "\n\t");
 490 #ifdef  HAVE_GETTOSBYNAME
 491     fprintf(stderr, " [-S tos]");
 492 #endif
 493 #ifdef  AUTHENTICATION
 494     fprintf(stderr, " [-X auth-type] [-y] [-z]");
 495 #endif
 496     fprintf(stderr, " [-u utmp_hostname_length] [-U]");
 497     fprintf(stderr, " [port]\n");
 498     exit(exit_code);
 499 }
 500
 501 /*
 502  * getterminaltype
 503  *
 504  *      Ask the other end to send along its terminal type and speed.
 505  * Output is the variable terminaltype filled in.
 506  */
 507 static unsigned char ttytype_sbbuf[] = {
 508     IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
 509 };
 510
 511 int
 512 getterminaltype(char *name, size_t name_sz)
 513 {
 514     int retval = -1;
 515
 516     settimer(baseline);
 517 #ifdef AUTHENTICATION
 518     /*
 519      * Handle the Authentication option before we do anything else.
 520      */
 521     send_do(TELOPT_AUTHENTICATION, 1);
 522     while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
 523         ttloop();
 524     if (his_state_is_will(TELOPT_AUTHENTICATION)) {
 525         retval = auth_wait(name, name_sz);
 526     }
 527 #endif
 528
 529 #ifdef ENCRYPTION
 530     send_will(TELOPT_ENCRYPT, 1);
 531     send_do(TELOPT_ENCRYPT, 1); /* esc@magic.fi */
 532 #endif
 533     send_do(TELOPT_TTYPE, 1);
 534     send_do(TELOPT_TSPEED, 1);
 535     send_do(TELOPT_XDISPLOC, 1);
 536     send_do(TELOPT_NEW_ENVIRON, 1);
 537     send_do(TELOPT_OLD_ENVIRON, 1);
 538     while (
 539 #ifdef ENCRYPTION
 540            his_do_dont_is_changing(TELOPT_ENCRYPT) ||
 541 #endif
 542            his_will_wont_is_changing(TELOPT_TTYPE) ||
 543            his_will_wont_is_changing(TELOPT_TSPEED) ||
 544            his_will_wont_is_changing(TELOPT_XDISPLOC) ||
 545            his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
 546            his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
 547         ttloop();
 548     }
 549 #ifdef ENCRYPTION
 550     /*
 551      * Wait for the negotiation of what type of encryption we can
 552      * send with.  If autoencrypt is not set, this will just return.
 553      */
 554     if (his_state_is_will(TELOPT_ENCRYPT)) {
 555         encrypt_wait();
 556     }
 557     if (require_encryption) {
 558
 559         while (encrypt_delay())
 560             if (telnet_spin())
 561                 fatal(net, "Failed while waiting for encryption");
 562
 563         if (!encrypt_is_encrypting())
 564             fatal(net, "Encryption required but not turned on by client");
 565     }
 566 #endif
 567     if (his_state_is_will(TELOPT_TSPEED)) {
 568         static unsigned char sb[] =
 569         { IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };
 570
 571         telnet_net_write (sb, sizeof sb);
 572         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 573     }
 574     if (his_state_is_will(TELOPT_XDISPLOC)) {
 575         static unsigned char sb[] =
 576         { IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
 577
 578         telnet_net_write (sb, sizeof sb);
 579         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 580     }
 581     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
 582         static unsigned char sb[] =
 583         { IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };
 584
 585         telnet_net_write (sb, sizeof sb);
 586         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 587     }
 588     else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
 589         static unsigned char sb[] =
 590         { IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };
 591
 592         telnet_net_write (sb, sizeof sb);
 593         DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
 594     }
 595     if (his_state_is_will(TELOPT_TTYPE)) {
 596
 597         telnet_net_write (ttytype_sbbuf, sizeof ttytype_sbbuf);
 598         DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
 599                                   sizeof ttytype_sbbuf - 2););
 600     }
 601     if (his_state_is_will(TELOPT_TSPEED)) {
 602         while (sequenceIs(tspeedsubopt, baseline))
 603             ttloop();
 604     }
 605     if (his_state_is_will(TELOPT_XDISPLOC)) {
 606         while (sequenceIs(xdisplocsubopt, baseline))
 607             ttloop();
 608     }
 609     if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
 610         while (sequenceIs(environsubopt, baseline))
 611             ttloop();
 612     }
 613     if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
 614         while (sequenceIs(oenvironsubopt, baseline))
 615             ttloop();
 616     }
 617     if (his_state_is_will(TELOPT_TTYPE)) {
 618         char first[256], last[256];
 619
 620         while (sequenceIs(ttypesubopt, baseline))
 621             ttloop();
 622
 623         /*
 624          * If the other side has already disabled the option, then
 625          * we have to just go with what we (might) have already gotten.
 626          */
 627         if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
 628             strlcpy(first, terminaltype, sizeof(first));
 629             for(;;) {
 630                 /*
 631                  * Save the unknown name, and request the next name.
 632                  */
 633                 strlcpy(last, terminaltype, sizeof(last));
 634                 _gettermname();
 635                 if (terminaltypeok(terminaltype))
 636                     break;
 637                 if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
 638                     his_state_is_wont(TELOPT_TTYPE)) {
 639                     /*
 640                      * We've hit the end.  If this is the same as
 641                      * the first name, just go with it.
 642                      */
 643                     if (strncmp(first, terminaltype, sizeof(first)) == 0)
 644                         break;
 645                     /*
 646                      * Get the terminal name one more time, so that
 647                      * RFC1091 compliant telnets will cycle back to
 648                      * the start of the list.
 649                      */
 650                     _gettermname();
 651                     if (strncmp(first, terminaltype, sizeof(first)) != 0)
 652                         strlcpy(terminaltype, first, sizeof(terminaltype));
 653                     break;
 654                 }
 655             }
 656         }
 657     }
 658     return(retval);
 659 }  /* end of getterminaltype */
 660
 661 void
 662 _gettermname(void)
 663 {
 664     /*
 665      * If the client turned off the option,
 666      * we can't send another request, so we
 667      * just return.
 668      */
 669     if (his_state_is_wont(TELOPT_TTYPE))
 670         return;
 671     settimer(baseline);
 672     telnet_net_write (ttytype_sbbuf, sizeof ttytype_sbbuf);
 673     DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
 674                               sizeof ttytype_sbbuf - 2););
 675     while (sequenceIs(ttypesubopt, baseline))
 676         ttloop();
 677 }
 678
 679 int
 680 terminaltypeok(char *s)
 681 {
 682     return 1;
 683 }
 684
 685
 686 char host_name[MaxHostNameLen];
 687 char remote_host_name[MaxHostNameLen];
 688 char remote_utmp_name[MaxHostNameLen];
 689
 690 /*
 691  * Get a pty, scan input lines.
 692  */
 693 static void
 694 doit(struct sockaddr *who, int who_len)
 695 {
 696     int level;
 697     int ptynum;
 698     char user_name[256];
 699     int error;
 700
 701     /*
 702      * Find an available pty to use.
 703      */
 704     ourpty = getpty(&ptynum);
 705     if (ourpty < 0)
 706         fatal(net, "All network ports in use");
 707
 708 #ifdef _SC_CRAY_SECURE_SYS
 709     /*
 710      *  set ttyp line security label
 711      */
 712     if (secflag) {
 713         char slave_dev[16];
 714
 715         snprintf(tty_dev, sizeof(tty_dev), "/dev/pty/%03d", ptynum);
 716         if (setdevs(tty_dev, &dv) < 0)
 717             fatal(net, "cannot set pty security");
 718         snprintf(slave_dev, sizeof(slave_dev), "/dev/ttyp%03d", ptynum);
 719         if (setdevs(slave_dev, &dv) < 0)
 720             fatal(net, "cannot set tty security");
 721     }
 722 #endif  /* _SC_CRAY_SECURE_SYS */
 723
 724     error = getnameinfo_verified (who, who_len,
 725                                   remote_host_name,
 726                                   sizeof(remote_host_name),
 727                                   NULL, 0,
 728                                   registerd_host_only ? NI_NAMEREQD : 0);
 729     if (error)
 730         fatal(net, "Couldn't resolve your address into a host name.\r\n\
 731 Please contact your net administrator");
 732
 733     gethostname(host_name, sizeof (host_name));
 734
 735     strlcpy (remote_utmp_name, remote_host_name, sizeof(remote_utmp_name));
 736
 737     /* Only trim if too long (and possible) */
 738     if (strlen(remote_utmp_name) > utmp_len) {
 739         char *domain = strchr(host_name, '.');
 740         char *p = strchr(remote_utmp_name, '.');
 741         if (domain != NULL && p != NULL && (strcmp(p, domain) == 0))
 742             *p = '\0'; /* remove domain part */
 743     }
 744
 745     /*
 746      * If hostname still doesn't fit utmp, use ipaddr.
 747      */
 748     if (strlen(remote_utmp_name) > utmp_len) {
 749         error = getnameinfo (who, who_len,
 750                              remote_utmp_name,
 751                              sizeof(remote_utmp_name),
 752                              NULL, 0,
 753                              NI_NUMERICHOST);
 754         if (error)
 755             fatal(net, "Couldn't get numeric address\r\n");
 756     }
 757
 758 #ifdef AUTHENTICATION
 759     auth_encrypt_init(host_name, remote_host_name, "TELNETD", 1);
 760 #endif
 761
 762     init_env();
 763
 764     /* begin server processing */
 765
 766     /*
 767      * Initialize the slc mapping table.
 768      */
 769
 770     get_slc_defaults();
 771
 772     /*
 773      * get terminal type.
 774      */
 775     *user_name = 0;
 776     level = getterminaltype(user_name, sizeof(user_name));
 777     esetenv("TERM", terminaltype[0] ? terminaltype : "network", 1);
 778
 779 #ifdef _SC_CRAY_SECURE_SYS
 780     if (secflag) {
 781         if (setulvl(dv.dv_actlvl) < 0)
 782             fatal(net,"cannot setulvl()");
 783         if (setucmp(dv.dv_actcmp) < 0)
 784             fatal(net, "cannot setucmp()");
 785     }
 786 #endif  /* _SC_CRAY_SECURE_SYS */
 787
 788     my_telnet(net, ourpty, remote_host_name, remote_utmp_name,
 789               level, user_name);
 790     /*NOTREACHED*/
 791 }  /* end of doit */
 792
 793 /* output contents of /etc/issue.net, or /etc/issue */
 794 static void
 795 show_issue(void)
 796 {
 797     FILE *f;
 798     char buf[128];
 799     f = fopen(SYSCONFDIR "/issue.net", "r");
 800     if(f == NULL)
 801         f = fopen(SYSCONFDIR "/issue", "r");
 802     if(f){
 803         while(fgets(buf, sizeof(buf), f) != NULL) {
 804             size_t len = strcspn(buf, "\r\n");
 805             if(len == strlen(buf)) {
 806                 /* there's no newline */
 807                 writenet(buf, len);
 808             } else {
 809                 /* replace newline with \r\n */
 810                 buf[len] = '\0';
 811                 writenet(buf, len);
 812                 writenet("\r\n", 2);
 813             }
 814         }
 815         fclose(f);
 816     }
 817 }
 818
 819 /*
 820  * Main loop.  Select from pty and network, and
 821  * hand data to telnet receiver finite state machine.
 822  */
 823 void
 824 my_telnet(int f, int p, const char *host, const char *utmp_host,
 825           int level, char *autoname)
 826 {
 827     int on = 1;
 828     char *he;
 829     char *IM;
 830     int nfd;
 831     int startslave_called = 0;
 832     time_t timeout;
 833
 834     /*
 835      * Do some tests where it is desireable to wait for a response.
 836      * Rather than doing them slowly, one at a time, do them all
 837      * at once.
 838      */
 839     if (my_state_is_wont(TELOPT_SGA))
 840         send_will(TELOPT_SGA, 1);
 841     /*
 842      * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
 843      * because 4.2 clients are unable to deal with TCP urgent data.
 844      *
 845      * To find out, we send out a "DO ECHO".  If the remote system
 846      * answers "WILL ECHO" it is probably a 4.2 client, and we note
 847      * that fact ("WILL ECHO" ==> that the client will echo what
 848      * WE, the server, sends it; it does NOT mean that the client will
 849      * echo the terminal input).
 850      */
 851     send_do(TELOPT_ECHO, 1);
 852
 853     /*
 854      * Send along a couple of other options that we wish to negotiate.
 855      */
 856     send_do(TELOPT_NAWS, 1);
 857     send_will(TELOPT_STATUS, 1);
 858     flowmode = 1;               /* default flow control state */
 859     restartany = -1;    /* uninitialized... */
 860     send_do(TELOPT_LFLOW, 1);
 861
 862     /*
 863      * Spin, waiting for a response from the DO ECHO.  However,
 864      * some REALLY DUMB telnets out there might not respond
 865      * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
 866      * telnets so far seem to respond with WONT for a DO that
 867      * they don't understand...) because by the time we get the
 868      * response, it will already have processed the DO ECHO.
 869      * Kludge upon kludge.
 870      */
 871     while (his_will_wont_is_changing(TELOPT_NAWS))
 872         ttloop();
 873
 874     /*
 875      * But...
 876      * The client might have sent a WILL NAWS as part of its
 877      * startup code; if so, we'll be here before we get the
 878      * response to the DO ECHO.  We'll make the assumption
 879      * that any implementation that understands about NAWS
 880      * is a modern enough implementation that it will respond
 881      * to our DO ECHO request; hence we'll do another spin
 882      * waiting for the ECHO option to settle down, which is
 883      * what we wanted to do in the first place...
 884      */
 885     if (his_want_state_is_will(TELOPT_ECHO) &&
 886         his_state_is_will(TELOPT_NAWS)) {
 887         while (his_will_wont_is_changing(TELOPT_ECHO))
 888             ttloop();
 889     }
 890     /*
 891      * On the off chance that the telnet client is broken and does not
 892      * respond to the DO ECHO we sent, (after all, we did send the
 893      * DO NAWS negotiation after the DO ECHO, and we won't get here
 894      * until a response to the DO NAWS comes back) simulate the
 895      * receipt of a will echo.  This will also send a WONT ECHO
 896      * to the client, since we assume that the client failed to
 897      * respond because it believes that it is already in DO ECHO
 898      * mode, which we do not want.
 899      */
 900     if (his_want_state_is_will(TELOPT_ECHO)) {
 901         DIAG(TD_OPTIONS,
 902              {output_data("td: simulating recv\r\n");
 903              });
 904         willoption(TELOPT_ECHO);
 905     }
 906
 907     /*
 908      * Finally, to clean things up, we turn on our echo.  This
 909      * will break stupid 4.2 telnets out of local terminal echo.
 910      */
 911
 912     if (my_state_is_wont(TELOPT_ECHO))
 913         send_will(TELOPT_ECHO, 1);
 914
 915 #ifdef TIOCPKT
 916 #ifdef  STREAMSPTY
 917     if (!really_stream)
 918 #endif
 919         /*
 920          * Turn on packet mode
 921          */
 922         ioctl(p, TIOCPKT, (char *)&on);
 923 #endif
 924
 925
 926     /*
 927      * Call telrcv() once to pick up anything received during
 928      * terminal type negotiation, 4.2/4.3 determination, and
 929      * linemode negotiation.
 930      */
 931     telrcv();
 932
 933     ioctl(f, FIONBIO, (char *)&on);
 934     ioctl(p, FIONBIO, (char *)&on);
 935
 936 #if     defined(SO_OOBINLINE) && defined(HAVE_SETSOCKOPT)
 937     setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
 938                (void *)&on, sizeof on);
 939 #endif  /* defined(SO_OOBINLINE) */
 940
 941 #ifdef  SIGTSTP
 942     signal(SIGTSTP, SIG_IGN);
 943 #endif
 944 #ifdef  SIGTTOU
 945     /*
 946      * Ignoring SIGTTOU keeps the kernel from blocking us
 947      * in ttioct() in /sys/tty.c.
 948      */
 949     signal(SIGTTOU, SIG_IGN);
 950 #endif
 951
 952     signal(SIGCHLD, cleanup);
 953
 954 #ifdef  TIOCNOTTY
 955     {
 956         int t;
 957         t = open(_PATH_TTY, O_RDWR);
 958         if (t >= 0) {
 959             ioctl(t, TIOCNOTTY, (char *)0);
 960             close(t);
 961         }
 962     }
 963 #endif
 964
 965     show_issue();
 966     /*
 967      * Show banner that getty never gave.
 968      *
 969      * We put the banner in the pty input buffer.  This way, it
 970      * gets carriage return null processing, etc., just like all
 971      * other pty --> client data.
 972      */
 973
 974     if (getenv("USER"))
 975         hostinfo = 0;
 976
 977     IM = DEFAULT_IM;
 978     he = 0;
 979     edithost(he, host_name);
 980     if (hostinfo && *IM)
 981         putf(IM, ptyibuf2);
 982
 983     if (pcc)
 984         strncat(ptyibuf2, ptyip, pcc+1);
 985     ptyip = ptyibuf2;
 986     pcc = strlen(ptyip);
 987
 988     DIAG(TD_REPORT, {
 989         output_data("td: Entering processing loop\r\n");
 990     });
 991
 992
 993     nfd = ((f > p) ? f : p) + 1;
 994     timeout = time(NULL) + 5;
 995     for (;;) {
 996         fd_set ibits, obits, xbits;
 997         int c;
 998
 999         /* wait for encryption to be turned on, but don't wait
1000            indefinitely */
1001         if(!startslave_called && (!encrypt_delay() || timeout > time(NULL))){
1002             startslave_called = 1;
1003             startslave(host, utmp_host, level, autoname);
1004         }
1005
1006         if (ncc < 0 && pcc < 0)
1007             break;
1008
1009         FD_ZERO(&ibits);
1010         FD_ZERO(&obits);
1011         FD_ZERO(&xbits);
1012
1013         if (f >= FD_SETSIZE
1014             || p >= FD_SETSIZE)
1015             fatal(net, "fd too large");
1016
1017         /*
1018          * Never look for input if there's still
1019          * stuff in the corresponding output buffer
1020          */
1021         if (nfrontp - nbackp || pcc > 0) {
1022             FD_SET(f, &obits);
1023         } else {
1024             FD_SET(p, &ibits);
1025         }
1026         if (pfrontp - pbackp || ncc > 0) {
1027             FD_SET(p, &obits);
1028         } else {
1029             FD_SET(f, &ibits);
1030         }
1031         if (!SYNCHing) {
1032             FD_SET(f, &xbits);
1033         }
1034         if ((c = select(nfd, &ibits, &obits, &xbits,
1035                         (struct timeval *)0)) < 1) {
1036             if (c == -1) {
1037                 if (errno == EINTR) {
1038                     continue;
1039                 }
1040             }
1041             sleep(5);
1042             continue;
1043         }
1044
1045         /*
1046          * Any urgent data?
1047          */
1048         if (FD_ISSET(net, &xbits)) {
1049             SYNCHing = 1;
1050         }
1051
1052         /*
1053          * Something to read from the network...
1054          */
1055         if (FD_ISSET(net, &ibits)) {
1056 #ifndef SO_OOBINLINE
1057             /*
1058              * In 4.2 (and 4.3 beta) systems, the
1059              * OOB indication and data handling in the kernel
1060              * is such that if two separate TCP Urgent requests
1061              * come in, one byte of TCP data will be overlaid.
1062              * This is fatal for Telnet, but we try to live
1063              * with it.
1064              *
1065              * In addition, in 4.2 (and...), a special protocol
1066              * is needed to pick up the TCP Urgent data in
1067              * the correct sequence.
1068              *
1069              * What we do is:  if we think we are in urgent
1070              * mode, we look to see if we are "at the mark".
1071              * If we are, we do an OOB receive.  If we run
1072              * this twice, we will do the OOB receive twice,
1073              * but the second will fail, since the second
1074              * time we were "at the mark", but there wasn't
1075              * any data there (the kernel doesn't reset
1076              * "at the mark" until we do a normal read).
1077              * Once we've read the OOB data, we go ahead
1078              * and do normal reads.
1079              *
1080              * There is also another problem, which is that
1081              * since the OOB byte we read doesn't put us
1082              * out of OOB state, and since that byte is most
1083              * likely the TELNET DM (data mark), we would
1084              * stay in the TELNET SYNCH (SYNCHing) state.
1085              * So, clocks to the rescue.  If we've "just"
1086              * received a DM, then we test for the
1087              * presence of OOB data when the receive OOB
1088              * fails (and AFTER we did the normal mode read
1089              * to clear "at the mark").
1090              */
1091             if (SYNCHing) {
1092                 int atmark;
1093
1094                 ioctl(net, SIOCATMARK, (char *)&atmark);
1095                 if (atmark) {
1096                     ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
1097                     if ((ncc == -1) && (errno == EINVAL)) {
1098                         ncc = read(net, netibuf, sizeof (netibuf));
1099                         if (sequenceIs(didnetreceive, gotDM)) {
1100                             SYNCHing = stilloob(net);
1101                         }
1102                     }
1103                 } else {
1104                     ncc = read(net, netibuf, sizeof (netibuf));
1105                 }
1106             } else {
1107                 ncc = read(net, netibuf, sizeof (netibuf));
1108             }
1109             settimer(didnetreceive);
1110 #else   /* !defined(SO_OOBINLINE)) */
1111             ncc = read(net, netibuf, sizeof (netibuf));
1112 #endif  /* !defined(SO_OOBINLINE)) */
1113             if (ncc < 0 && errno == EWOULDBLOCK)
1114                 ncc = 0;
1115             else {
1116                 if (ncc <= 0) {
1117                     break;
1118                 }
1119                 netip = netibuf;
1120             }
1121             DIAG((TD_REPORT | TD_NETDATA), {
1122                 output_data("td: netread %d chars\r\n", ncc);
1123                 });
1124             DIAG(TD_NETDATA, printdata("nd", netip, ncc));
1125         }
1126
1127         /*
1128          * Something to read from the pty...
1129          */
1130         if (FD_ISSET(p, &ibits)) {
1131 #ifdef STREAMSPTY
1132             if (really_stream)
1133                 pcc = readstream(p, ptyibuf, BUFSIZ);
1134             else
1135 #endif
1136                 pcc = read(p, ptyibuf, BUFSIZ);
1137
1138             /*
1139              * On some systems, if we try to read something
1140              * off the master side before the slave side is
1141              * opened, we get EIO.
1142              */
1143             if (pcc < 0 && (errno == EWOULDBLOCK ||
1144 #ifdef  EAGAIN
1145                             errno == EAGAIN ||
1146 #endif
1147                             errno == EIO)) {
1148                 pcc = 0;
1149             } else {
1150                 if (pcc <= 0)
1151                     break;
1152                 if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
1153                     netclear(); /* clear buffer back */
1154 #ifndef NO_URGENT
1155                     /*
1156                      * There are client telnets on some
1157                      * operating systems get screwed up
1158                      * royally if we send them urgent
1159                      * mode data.
1160                      */
1161                     output_data ("%c%c", IAC, DM);
1162
1163                     neturg = nfrontp-1; /* off by one XXX */
1164                     DIAG(TD_OPTIONS,
1165                          printoption("td: send IAC", DM));
1166
1167 #endif
1168                 }
1169                 if (his_state_is_will(TELOPT_LFLOW) &&
1170                     (ptyibuf[0] &
1171                      (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
1172                     int newflow =
1173                         ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
1174                     if (newflow != flowmode) {
1175                         flowmode = newflow;
1176                         output_data("%c%c%c%c%c%c",
1177                                     IAC, SB, TELOPT_LFLOW,
1178                                     flowmode ? LFLOW_ON
1179                                     : LFLOW_OFF,
1180                                     IAC, SE);
1181                         DIAG(TD_OPTIONS, printsub('>',
1182                                                   (unsigned char *)nfrontp-4,
1183                                                   4););
1184                     }
1185                 }
1186                 pcc--;
1187                 ptyip = ptyibuf+1;
1188             }
1189         }
1190
1191         while (pcc > 0) {
1192             if ((&netobuf[BUFSIZ] - nfrontp) < 3)
1193                 break;
1194             c = *ptyip++ & 0377, pcc--;
1195             if (c == IAC)
1196                 *nfrontp++ = c;
1197             *nfrontp++ = c;
1198             if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
1199                 if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
1200                     *nfrontp++ = *ptyip++ & 0377;
1201                     pcc--;
1202                 } else
1203                     *nfrontp++ = '\0';
1204             }
1205         }
1206
1207         if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
1208             netflush();
1209         if (ncc > 0)
1210             telrcv();
1211         if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
1212             ptyflush();
1213     }
1214     cleanup(0);
1215 }
1216
1217 #ifndef TCSIG
1218 # ifdef TIOCSIG
1219 #  define TCSIG TIOCSIG
1220 # endif
1221 #endif
1222
1223 #ifdef  STREAMSPTY
1224
1225     int flowison = -1;  /* current state of flow: -1 is unknown */
1226
1227 int
1228 readstream(int p, char *ibuf, int bufsize)
1229 {
1230     int flags = 0;
1231     int ret = 0;
1232     struct termios *tsp;
1233 #if 0
1234     struct termio *tp;
1235 #endif
1236     struct iocblk *ip;
1237     char vstop, vstart;
1238     int ixon;
1239     int newflow;
1240
1241     strbufc.maxlen = BUFSIZ;
1242     strbufc.buf = (char *)ctlbuf;
1243     strbufd.maxlen = bufsize-1;
1244     strbufd.len = 0;
1245     strbufd.buf = ibuf+1;
1246     ibuf[0] = 0;
1247
1248     ret = getmsg(p, &strbufc, &strbufd, &flags);
1249     if (ret < 0)  /* error of some sort -- probably EAGAIN */
1250         return(-1);
1251
1252     if (strbufc.len <= 0 || ctlbuf[0] == M_DATA) {
1253         /* data message */
1254         if (strbufd.len > 0) {                  /* real data */
1255             return(strbufd.len + 1);    /* count header char */
1256         } else {
1257             /* nothing there */
1258             errno = EAGAIN;
1259             return(-1);
1260         }
1261     }
1262
1263     /*
1264      * It's a control message.  Return 1, to look at the flag we set
1265      */
1266
1267     switch (ctlbuf[0]) {
1268     case M_FLUSH:
1269         if (ibuf[1] & FLUSHW)
1270             ibuf[0] = TIOCPKT_FLUSHWRITE;
1271         return(1);
1272
1273     case M_IOCTL:
1274         ip = (struct iocblk *) (ibuf+1);
1275
1276         switch (ip->ioc_cmd) {
1277 #ifdef TCSETS
1278         case TCSETS:
1279         case TCSETSW:
1280         case TCSETSF:
1281             tsp = (struct termios *)
1282                 (ibuf+1 + sizeof(struct iocblk));
1283             vstop = tsp->c_cc[VSTOP];
1284             vstart = tsp->c_cc[VSTART];
1285             ixon = tsp->c_iflag & IXON;
1286             break;
1287 #endif
1288 #if 0
1289         case TCSETA:
1290         case TCSETAW:
1291         case TCSETAF:
1292             tp = (struct termio *) (ibuf+1 + sizeof(struct iocblk));
1293             vstop = tp->c_cc[VSTOP];
1294             vstart = tp->c_cc[VSTART];
1295             ixon = tp->c_iflag & IXON;
1296             break;
1297 #endif
1298         default:
1299             errno = EAGAIN;
1300             return(-1);
1301         }
1302
1303         newflow =  (ixon && (vstart == 021) && (vstop == 023)) ? 1 : 0;
1304         if (newflow != flowison) {  /* it's a change */
1305             flowison = newflow;
1306             ibuf[0] = newflow ? TIOCPKT_DOSTOP : TIOCPKT_NOSTOP;
1307             return(1);
1308         }
1309     }
1310
1311     /* nothing worth doing anything about */
1312     errno = EAGAIN;
1313     return(-1);
1314 }
1315 #endif /* STREAMSPTY */
1316
1317 /*
1318  * Send interrupt to process on other side of pty.
1319  * If it is in raw mode, just write NULL;
1320  * otherwise, write intr char.
1321  */
1322 void
1323 interrupt()
1324 {
1325     ptyflush(); /* half-hearted */
1326
1327 #if defined(STREAMSPTY) && defined(TIOCSIGNAL)
1328     /* Streams PTY style ioctl to post a signal */
1329     if (really_stream)
1330         {
1331             int sig = SIGINT;
1332             ioctl(ourpty, TIOCSIGNAL, &sig);
1333             ioctl(ourpty, I_FLUSH, FLUSHR);
1334         }
1335 #else
1336 #ifdef  TCSIG
1337     ioctl(ourpty, TCSIG, (char *)SIGINT);
1338 #else   /* TCSIG */
1339     init_termbuf();
1340     *pfrontp++ = slctab[SLC_IP].sptr ?
1341         (unsigned char)*slctab[SLC_IP].sptr : '\177';
1342 #endif  /* TCSIG */
1343 #endif
1344 }
1345
1346 /*
1347  * Send quit to process on other side of pty.
1348  * If it is in raw mode, just write NULL;
1349  * otherwise, write quit char.
1350  */
1351 void
1352 sendbrk()
1353 {
1354     ptyflush(); /* half-hearted */
1355 #ifdef  TCSIG
1356     ioctl(ourpty, TCSIG, (char *)SIGQUIT);
1357 #else   /* TCSIG */
1358     init_termbuf();
1359     *pfrontp++ = slctab[SLC_ABORT].sptr ?
1360         (unsigned char)*slctab[SLC_ABORT].sptr : '\034';
1361 #endif  /* TCSIG */
1362 }
1363
1364 void
1365 sendsusp()
1366 {
1367 #ifdef  SIGTSTP
1368     ptyflush(); /* half-hearted */
1369 # ifdef TCSIG
1370     ioctl(ourpty, TCSIG, (char *)SIGTSTP);
1371 # else  /* TCSIG */
1372     *pfrontp++ = slctab[SLC_SUSP].sptr ?
1373         (unsigned char)*slctab[SLC_SUSP].sptr : '\032';
1374 # endif /* TCSIG */
1375 #endif  /* SIGTSTP */
1376 }
1377
1378 /*
1379  * When we get an AYT, if ^T is enabled, use that.  Otherwise,
1380  * just send back "[Yes]".
1381  */
1382 void
1383 recv_ayt()
1384 {
1385 #if     defined(SIGINFO) && defined(TCSIG)
1386     if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
1387         ioctl(ourpty, TCSIG, (char *)SIGINFO);
1388         return;
1389     }
1390 #endif
1391     output_data("\r\n[Yes]\r\n");
1392 }
1393
1394 void
1395 doeof()
1396 {
1397     init_termbuf();
1398
1399     *pfrontp++ = slctab[SLC_EOF].sptr ?
1400         (unsigned char)*slctab[SLC_EOF].sptr : '\004';
1401 }