/* $NetBSD: telnetd.c,v 1.60 2024/10/29 13:10:10 kre Exp $ */ /* * Copyright (C) 1997 and 1998 WIDE Project. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1989, 1993\ The Regents of the University of California. All rights reserved."); #if 0 static char sccsid[] = "@(#)telnetd.c 8.4 (Berkeley) 5/30/95"; #else __RCSID("$NetBSD: telnetd.c,v 1.60 2024/10/29 13:10:10 kre Exp $"); #endif #endif /* not lint */ #include "telnetd.h" #include "pathnames.h" #include #include #include #include #ifdef KRB5 #define Authenticator k5_Authenticator #include #undef Authenticator #include #endif #if defined(AUTHENTICATION) || defined(ENCRYPTION) #include #endif extern int require_hwpreauth; #ifdef KRB5 extern krb5_context telnet_context; #endif int registerd_host_only = 0; /* * I/O data buffers, * pointers, and counters. */ char ptyibuf[BUFSIZ], *ptyip = ptyibuf; char ptyibuf2[BUFSIZ]; int hostinfo = 1; /* do we print login banner? */ static int debug = 0; int keepalive = 1; const char *gettyname = "default"; char *progname; void usage(void) __dead; int getterminaltype(char *, size_t); int getent(char *, const char *); static void doit(struct sockaddr *) __dead; void _gettermname(void); int terminaltypeok(char *); char *getstr(const char *, char **); /* * The string to pass to getopt(). We do it this way so * that only the actual options that we support will be * passed off to getopt(). */ char valid_opts[] = { 'd', ':', 'g', ':', 'h', 'k', 'n', 'S', ':', 'u', ':', 'U', '4', '6', #ifdef AUTHENTICATION 'a', ':', 'X', ':', #endif #ifdef ENCRYPTION 'e', ':', #endif #ifdef DIAGNOSTICS 'D', ':', #endif #ifdef LINEMODE 'l', #endif #ifdef SECURELOGIN 's', #endif #ifdef KRB5 'R', ':', 'H', #endif '\0' }; int family = AF_INET; struct sockaddr_storage from; int main(int argc, char *argv[]) { static char Xline[] = NULL16STR; socklen_t fromlen; int on = 1; int ch; #if defined(IPPROTO_IP) && defined(IP_TOS) int tos = -1; #endif line = Xline; pfrontp = pbackp = ptyobuf; netip = netibuf; nfrontp = nbackp = netobuf; #ifdef ENCRYPTION nclearto = 0; #endif /* ENCRYPTION */ progname = *argv; while ((ch = getopt(argc, argv, valid_opts)) != -1) { switch (ch) { #ifdef AUTHENTICATION case 'a': /* * Check for required authentication level */ if (strcmp(optarg, "debug") == 0) { auth_debug_mode = 1; } else if (strcasecmp(optarg, "none") == 0) { auth_level = 0; } else if (strcasecmp(optarg, "other") == 0) { auth_level = AUTH_OTHER; } else if (strcasecmp(optarg, "user") == 0) { auth_level = AUTH_USER; } else if (strcasecmp(optarg, "valid") == 0) { auth_level = AUTH_VALID; } else if (strcasecmp(optarg, "off") == 0) { /* * This hack turns off authentication */ auth_level = -1; } else { fprintf(stderr, "telnetd: unknown authorization level for -a\n"); } break; #endif /* AUTHENTICATION */ case 'd': if (strcmp(optarg, "ebug") == 0) { debug++; break; } usage(); /* NOTREACHED */ break; #ifdef DIAGNOSTICS case 'D': /* * Check for desired diagnostics capabilities. */ if (!strcmp(optarg, "report")) { diagnostic |= TD_REPORT|TD_OPTIONS; } else if (!strcmp(optarg, "exercise")) { diagnostic |= TD_EXERCISE; } else if (!strcmp(optarg, "netdata")) { diagnostic |= TD_NETDATA; } else if (!strcmp(optarg, "ptydata")) { diagnostic |= TD_PTYDATA; } else if (!strcmp(optarg, "options")) { diagnostic |= TD_OPTIONS; } else { usage(); /* NOT REACHED */ } break; #endif /* DIAGNOSTICS */ #ifdef ENCRYPTION case 'e': if (strcmp(optarg, "debug") == 0) { EncryptDebug(1); break; } usage(); /* NOTREACHED */ break; #endif /* ENCRYPTION */ case 'g': gettyname = optarg; break; case 'h': hostinfo = 0; break; #ifdef KRB5 case 'H': { require_hwpreauth = 1; break; } #endif /* KRB5 */ #ifdef LINEMODE case 'l': alwayslinemode = 1; break; #endif /* LINEMODE */ case 'k': #if defined(LINEMODE) && defined(KLUDGELINEMODE) lmodetype = NO_AUTOKLUDGE; #else /* ignore -k option if built without kludge linemode */ #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ break; case 'n': keepalive = 0; break; #ifdef KRB5 case 'R': { krb5_error_code retval; if (telnet_context == 0) { retval = krb5_init_context(&telnet_context); if (retval) { com_err("telnetd", retval, "while initializing krb5"); exit(1); } } krb5_set_default_realm(telnet_context, optarg); break; } #endif /* KRB5 */ #ifdef SECURELOGIN case 's': /* Secure login required */ require_secure_login = 1; break; #endif /* SECURELOGIN */ case 'S': fprintf(stderr, "%s%s\n", "TOS option unavailable; ", "-S flag not supported\n"); break; case 'u': fprintf(stderr, "telnetd: -u option unneeded\n"); break; case 'U': registerd_host_only = 1; break; #ifdef AUTHENTICATION case 'X': /* * Check for invalid authentication types */ auth_disable_name(optarg); break; #endif /* AUTHENTICATION */ case '4': family = AF_INET; break; case '6': family = AF_INET6; break; default: fprintf(stderr, "telnetd: %c: unknown option\n", ch); /* FALLTHROUGH */ case '?': usage(); /* NOTREACHED */ } } argc -= optind; argv += optind; if (debug) { int s, ns, error; socklen_t foo; const char *service = "telnet"; struct addrinfo hints, *res; if (argc > 1) { usage(); /* NOT REACHED */ } else if (argc == 1) service = *argv; memset(&hints, 0, sizeof(hints)); hints.ai_flags = AI_PASSIVE; hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; error = getaddrinfo(NULL, service, &hints, &res); if (error) { fprintf(stderr, "tcp/%s: %s\n", service, gai_strerror(error)); exit(1); } s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (s < 0) { perror("telnetd: socket"); exit(1); } (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on)); if (bind(s, res->ai_addr, res->ai_addrlen) < 0) { perror("bind"); exit(1); } if (listen(s, 1) < 0) { perror("listen"); exit(1); } foo = res->ai_addrlen; ns = accept(s, res->ai_addr, &foo); if (ns < 0) { perror("accept"); exit(1); } (void) dup2(ns, 0); (void) close(ns); (void) close(s); freeaddrinfo(res); } else if (argc > 0) { usage(); /* NOT REACHED */ } openlog("telnetd", LOG_PID, LOG_DAEMON); fromlen = sizeof (from); if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { fprintf(stderr, "%s: ", progname); perror("getpeername"); _exit(1); } if (keepalive && setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof (on)) < 0) { syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); } #if defined(IPPROTO_IP) && defined(IP_TOS) if (((struct sockaddr *)&from)->sa_family == AF_INET) { if (tos < 0) tos = 020; /* Low Delay bit */ if (tos && (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(tos)) < 0) && (errno != ENOPROTOOPT) ) syslog(LOG_WARNING, "setsockopt (IP_TOS): %m"); } #endif /* defined(IPPROTO_IP) && defined(IP_TOS) */ net = 0; doit((struct sockaddr *)&from); /* NOTREACHED */ #ifdef __GNUC__ exit(0); #endif } /* end of main */ void usage(void) { fprintf(stderr, "Usage: telnetd"); #ifdef AUTHENTICATION fprintf(stderr, " [-a (debug|other|user|valid|off|none)]\n\t"); #endif fprintf(stderr, " [-debug]"); #ifdef DIAGNOSTICS fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t"); #endif #ifdef ENCRYPTION fprintf(stderr, " [-edebug]"); #endif fprintf(stderr, " [-h]"); #if defined(LINEMODE) && defined(KLUDGELINEMODE) fprintf(stderr, " [-k]"); #endif #ifdef LINEMODE fprintf(stderr, " [-l]"); #endif fprintf(stderr, " [-n]"); fprintf(stderr, "\n\t"); #ifdef SECURELOGIN fprintf(stderr, " [-s]"); #endif #ifdef AUTHENTICATION fprintf(stderr, " [-X auth-type]"); #endif fprintf(stderr, " [-u utmp_hostname_length] [-U]"); fprintf(stderr, " [port]\n"); exit(1); } /* * getterminaltype * * Ask the other end to send along its terminal type and speed. * Output is the variable terminaltype filled in. */ static unsigned char ttytype_sbbuf[] = { IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE }; int getterminaltype(char *name, size_t l) { int retval = -1; settimer(baseline); #ifdef AUTHENTICATION /* * Handle the Authentication option before we do anything else. */ if (auth_level >= 0) { send_do(TELOPT_AUTHENTICATION, 1); while (his_will_wont_is_changing(TELOPT_AUTHENTICATION)) ttloop(); if (his_state_is_will(TELOPT_AUTHENTICATION)) { retval = auth_wait(name, l); } } #endif #ifdef ENCRYPTION send_will(TELOPT_ENCRYPT, 1); #endif /* ENCRYPTION */ send_do(TELOPT_TTYPE, 1); send_do(TELOPT_TSPEED, 1); send_do(TELOPT_XDISPLOC, 1); send_do(TELOPT_NEW_ENVIRON, 1); send_do(TELOPT_OLD_ENVIRON, 1); while ( #ifdef ENCRYPTION his_do_dont_is_changing(TELOPT_ENCRYPT) || #endif /* ENCRYPTION */ his_will_wont_is_changing(TELOPT_TTYPE) || his_will_wont_is_changing(TELOPT_TSPEED) || his_will_wont_is_changing(TELOPT_XDISPLOC) || his_will_wont_is_changing(TELOPT_NEW_ENVIRON) || his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) { ttloop(); } if (his_state_is_will(TELOPT_TSPEED)) { static unsigned char sb[] = { IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE }; output_datalen((const char *)sb, sizeof sb); DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); } #ifdef ENCRYPTION /* * Wait for the negotiation of what type of encryption we can * send with. If autoencrypt is not set, this will just return. */ if (his_state_is_will(TELOPT_ENCRYPT)) { encrypt_wait(); } #endif /* ENCRYPTION */ if (his_state_is_will(TELOPT_XDISPLOC)) { static unsigned char sb[] = { IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE }; output_datalen((const char *)sb, sizeof sb); DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); } if (his_state_is_will(TELOPT_NEW_ENVIRON)) { static unsigned char sb[] = { IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE }; output_datalen((const char *)sb, sizeof sb); DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); } else if (his_state_is_will(TELOPT_OLD_ENVIRON)) { static unsigned char sb[] = { IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE }; output_datalen((const char *)sb, sizeof sb); DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2);); } if (his_state_is_will(TELOPT_TTYPE)) { output_datalen((const char *)ttytype_sbbuf, sizeof ttytype_sbbuf); DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2, sizeof ttytype_sbbuf - 2);); } if (his_state_is_will(TELOPT_TSPEED)) { while (sequenceIs(tspeedsubopt, baseline)) ttloop(); } if (his_state_is_will(TELOPT_XDISPLOC)) { while (sequenceIs(xdisplocsubopt, baseline)) ttloop(); } if (his_state_is_will(TELOPT_NEW_ENVIRON)) { while (sequenceIs(environsubopt, baseline)) ttloop(); } if (his_state_is_will(TELOPT_OLD_ENVIRON)) { while (sequenceIs(oenvironsubopt, baseline)) ttloop(); } if (his_state_is_will(TELOPT_TTYPE)) { char first[256], last[256]; while (sequenceIs(ttypesubopt, baseline)) ttloop(); /* * If the other side has already disabled the option, then * we have to just go with what we (might) have already gotten. */ if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) { (void) strlcpy(first, terminaltype, sizeof(first)); for(;;) { /* * Save the unknown name, and request the next name. */ (void) strlcpy(last, terminaltype, sizeof(last)); _gettermname(); if (terminaltypeok(terminaltype)) break; if ((strncmp(last, terminaltype, sizeof(last)) == 0) || his_state_is_wont(TELOPT_TTYPE)) { /* * We've hit the end. If this is the same as * the first name, just go with it. */ if (strncmp(first, terminaltype, sizeof(first)) == 0) break; /* * Get the terminal name one more time, so that * RFC1091 compliant telnets will cycle back to * the start of the list. */ _gettermname(); if (strncmp(first, terminaltype, sizeof(first)) != 0) { (void) strlcpy(terminaltype, first, sizeof(terminaltype)); } break; } } } } return(retval); } /* end of getterminaltype */ void _gettermname(void) { /* * If the client turned off the option, * we can't send another request, so we * just return. */ if (his_state_is_wont(TELOPT_TTYPE)) return; settimer(baseline); output_datalen((const char *)ttytype_sbbuf, sizeof ttytype_sbbuf); DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2, sizeof ttytype_sbbuf - 2);); while (sequenceIs(ttypesubopt, baseline)) ttloop(); } int terminaltypeok(char *s) { char buf[1024]; /* * tgetent() will return 1 if the type is known, and * 0 if it is not known. If it returns -1, it couldn't * open the database. But if we can't open the database, * it won't help to say we failed, because we won't be * able to verify anything else. So, we treat -1 like 1. */ if (tgetent(buf, s) == 0) return(0); return(1); } char *hostname; char host_name[MAXHOSTNAMELEN + 1]; char remote_host_name[MAXHOSTNAMELEN + 1]; static void telnet(int, int) __dead; /* * Get a pty, scan input lines. */ static void doit(struct sockaddr *who) { char *host; int error; int level; int ptynum; int flags; char user_name[256]; /* * Initialize the slc mapping table. */ get_slc_defaults(); /* * Find an available pty to use. */ pty = getpty(&ptynum); if (pty < 0) fatal(net, "All network ports in use"); flags = registerd_host_only ? NI_NAMEREQD : 0; /* get name of connected client */ error = getnameinfo(who, who->sa_len, remote_host_name, sizeof(remote_host_name), NULL, 0, flags); if (error) { fatal(net, "Couldn't resolve your address into a host name.\r\n\ Please contact your net administrator"); #ifdef __GNUC__ host = NULL; /* XXX gcc */ #endif } remote_host_name[sizeof(remote_host_name)-1] = 0; host = remote_host_name; (void)gethostname(host_name, sizeof(host_name)); host_name[sizeof(host_name) - 1] = '\0'; hostname = host_name; #if defined(AUTHENTICATION) || defined(ENCRYPTION) auth_encrypt_init(hostname, host, "TELNETD", 1); #endif init_env(); /* * get terminal type. */ *user_name = 0; level = getterminaltype(user_name, sizeof(user_name)); setenv("TERM", terminaltype[0] ? terminaltype : "network", 1); /* * Start up the login process on the slave side of the terminal */ startslave(host, level, user_name); telnet(net, pty); /* begin server processing */ /*NOTREACHED*/ } /* end of doit */ /* * Main loop. Select from pty and network, and * hand data to telnet receiver finite state machine. */ static void telnet(int f, int p) { int on = 1; #define TABBUFSIZ 512 char defent[TABBUFSIZ]; char defstrs[TABBUFSIZ]; #undef TABBUFSIZ char *HE, *HN, *IF, *ptyibuf2ptr; const char *IM; struct pollfd set[2]; /* * Do some tests where it is desirable to wait for a response. * Rather than doing them slowly, one at a time, do them all * at once. */ if (my_state_is_wont(TELOPT_SGA)) send_will(TELOPT_SGA, 1); /* * Is the client side a 4.2 (NOT 4.3) system? We need to know this * because 4.2 clients are unable to deal with TCP urgent data. * * To find out, we send out a "DO ECHO". If the remote system * answers "WILL ECHO" it is probably a 4.2 client, and we note * that fact ("WILL ECHO" ==> that the client will echo what * WE, the server, sends it; it does NOT mean that the client will * echo the terminal input). */ send_do(TELOPT_ECHO, 1); #ifdef LINEMODE if (his_state_is_wont(TELOPT_LINEMODE)) { /* Query the peer for linemode support by trying to negotiate * the linemode option. */ linemode = 0; editmode = 0; send_do(TELOPT_LINEMODE, 1); /* send do linemode */ } #endif /* LINEMODE */ /* * Send along a couple of other options that we wish to negotiate. */ send_do(TELOPT_NAWS, 1); send_will(TELOPT_STATUS, 1); flowmode = 1; /* default flow control state */ restartany = -1; /* uninitialized... */ send_do(TELOPT_LFLOW, 1); /* * Spin, waiting for a response from the DO ECHO. However, * some REALLY DUMB telnets out there might not respond * to the DO ECHO. So, we spin looking for NAWS, (most dumb * telnets so far seem to respond with WONT for a DO that * they don't understand...) because by the time we get the * response, it will already have processed the DO ECHO. * Kludge upon kludge. */ while (his_will_wont_is_changing(TELOPT_NAWS)) ttloop(); /* * But... * The client might have sent a WILL NAWS as part of its * startup code; if so, we'll be here before we get the * response to the DO ECHO. We'll make the assumption * that any implementation that understands about NAWS * is a modern enough implementation that it will respond * to our DO ECHO request; hence we'll do another spin * waiting for the ECHO option to settle down, which is * what we wanted to do in the first place... */ if (his_want_state_is_will(TELOPT_ECHO) && his_state_is_will(TELOPT_NAWS)) { while (his_will_wont_is_changing(TELOPT_ECHO)) ttloop(); } /* * On the off chance that the telnet client is broken and does not * respond to the DO ECHO we sent, (after all, we did send the * DO NAWS negotiation after the DO ECHO, and we won't get here * until a response to the DO NAWS comes back) simulate the * receipt of a will echo. This will also send a WONT ECHO * to the client, since we assume that the client failed to * respond because it believes that it is already in DO ECHO * mode, which we do not want. */ if (his_want_state_is_will(TELOPT_ECHO)) { DIAG(TD_OPTIONS, {output_data("td: simulating recv\r\n");}); willoption(TELOPT_ECHO); } /* * Finally, to clean things up, we turn on our echo. This * will break stupid 4.2 telnets out of local terminal echo. */ if (my_state_is_wont(TELOPT_ECHO)) send_will(TELOPT_ECHO, 1); /* * Turn on packet mode */ (void) ioctl(p, TIOCPKT, (char *)&on); #if defined(LINEMODE) && defined(KLUDGELINEMODE) /* * Continuing line mode support. If client does not support * real linemode, attempt to negotiate kludge linemode by sending * the do timing mark sequence. */ if (lmodetype < REAL_LINEMODE) send_do(TELOPT_TM, 1); #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ /* * Call telrcv() once to pick up anything received during * terminal type negotiation, 4.2/4.3 determination, and * linemode negotiation. */ telrcv(); (void) ioctl(f, FIONBIO, (char *)&on); (void) ioctl(p, FIONBIO, (char *)&on); (void) setsockopt(f, SOL_SOCKET, SO_OOBINLINE, (char *)&on, sizeof on); (void) signal(SIGTSTP, SIG_IGN); /* * Ignoring SIGTTOU keeps the kernel from blocking us * in ttioct() in /sys/tty.c. */ (void) signal(SIGTTOU, SIG_IGN); (void) signal(SIGCHLD, cleanup); { int t; t = open(_PATH_TTY, O_RDWR); if (t >= 0) { (void) ioctl(t, TIOCNOTTY, (char *)0); (void) close(t); } } /* * Show banner that getty never gave. * * We put the banner in the pty input buffer. This way, it * gets carriage return null processing, etc., just like all * other pty --> client data. */ if (getent(defent, gettyname) == 1) { char *cp=defstrs; HE = getstr("he", &cp); HN = getstr("hn", &cp); IM = getstr("im", &cp); IF = getstr("if", &cp); if (HN && *HN) (void)strlcpy(host_name, HN, sizeof(host_name)); if (IM == 0) IM = ""; } else { IM = DEFAULT_IM; HE = 0; IF = NULL; } edithost(HE, host_name); ptyibuf2ptr = ptyibuf2; if (hostinfo) { if (IF) { char buf[_POSIX2_LINE_MAX]; FILE *fd; if ((fd = fopen(IF, "r")) != NULL) { while (fgets(buf, sizeof(buf) - 1, fd) != NULL) ptyibuf2ptr = putf(buf, ptyibuf2ptr); fclose(fd); } } if (*IM) ptyibuf2ptr = putf(IM, ptyibuf2ptr); } if (pcc) strncpy(ptyibuf2ptr, ptyip, pcc+1); ptyip = ptyibuf2; pcc = strlen(ptyip); #ifdef LINEMODE /* * Last check to make sure all our states are correct. */ init_termbuf(); localstat(); #endif /* LINEMODE */ DIAG(TD_REPORT, {output_data("td: Entering processing loop\r\n");}); set[0].fd = f; set[1].fd = p; for (;;) { int c; if (ncc < 0 && pcc < 0) break; /* * Never look for input if there's still * stuff in the corresponding output buffer */ set[0].events = 0; set[1].events = 0; if (nfrontp - nbackp || pcc > 0) set[0].events |= POLLOUT; else set[1].events |= POLLIN; if (pfrontp - pbackp || ncc > 0) set[1].events |= POLLOUT; else set[0].events |= POLLIN; if (!SYNCHing) set[0].events |= POLLPRI; if ((c = poll(set, 2, INFTIM)) < 1) { if (c == -1) { if (errno == EINTR) { continue; } } sleep(5); continue; } /* * Any urgent data? */ if (set[0].revents & POLLPRI) { SYNCHing = 1; } /* * Something to read from the network... */ if (set[0].revents & POLLIN) { ncc = read(f, netibuf, sizeof (netibuf)); if (ncc < 0 && errno == EWOULDBLOCK) ncc = 0; else { if (ncc <= 0) { break; } netip = netibuf; } DIAG((TD_REPORT | TD_NETDATA), {output_data("td: netread %d chars\r\n", ncc);}); DIAG(TD_NETDATA, printdata("nd", netip, ncc)); } /* * Something to read from the pty... */ if (set[1].revents & POLLIN) { pcc = read(p, ptyibuf, BUFSIZ); /* * On some systems, if we try to read something * off the master side before the slave side is * opened, we get EIO. */ if (pcc < 0 && (errno == EWOULDBLOCK || errno == EAGAIN || errno == EIO)) { pcc = 0; } else { if (pcc <= 0) break; #ifdef LINEMODE /* * If ioctl from pty, pass it through net */ if (ptyibuf[0] & TIOCPKT_IOCTL) { copy_termbuf(ptyibuf+1, pcc-1); localstat(); pcc = 1; } #endif /* LINEMODE */ if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) { netclear(); /* clear buffer back */ /* * There are client telnets on some * operating systems get screwed up * royally if we send them urgent * mode data. */ output_data("%c%c", IAC, DM); neturg = nfrontp - 1; /* off by one XXX */ DIAG(TD_OPTIONS, printoption("td: send IAC", DM)); } if (his_state_is_will(TELOPT_LFLOW) && (ptyibuf[0] & (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) { int newflow = ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0; if (newflow != flowmode) { flowmode = newflow; (void) output_data( "%c%c%c%c%c%c", IAC, SB, TELOPT_LFLOW, flowmode ? LFLOW_ON : LFLOW_OFF, IAC, SE); DIAG(TD_OPTIONS, printsub('>', (unsigned char *)nfrontp - 4, 4);); } } pcc--; ptyip = ptyibuf+1; } } while (pcc > 0) { if ((&netobuf[BUFSIZ] - nfrontp) < 2) break; c = *ptyip++ & 0377, pcc--; if (c == IAC) output_data("%c", c); output_data("%c", c); if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) { if (pcc > 0 && ((*ptyip & 0377) == '\n')) { output_data("%c", *ptyip++ & 0377); pcc--; } else output_datalen("\0", 1); } } if ((set[0].revents & POLLOUT) && (nfrontp - nbackp) > 0) netflush(); if (ncc > 0) telrcv(); if ((set[1].revents & POLLOUT) && (pfrontp - pbackp) > 0) ptyflush(); } cleanup(0); } /* end of telnet */ /* * Send interrupt to process on other side of pty. * If it is in raw mode, just write NULL; * otherwise, write intr char. */ void interrupt(void) { ptyflush(); /* half-hearted */ (void) ioctl(pty, TIOCSIG, (char *)SIGINT); } /* * Send quit to process on other side of pty. * If it is in raw mode, just write NULL; * otherwise, write quit char. */ void sendbrk(void) { ptyflush(); /* half-hearted */ (void) ioctl(pty, TIOCSIG, (char *)SIGQUIT); } void sendsusp(void) { ptyflush(); /* half-hearted */ (void) ioctl(pty, TIOCSIG, (char *)SIGTSTP); } /* * When we get an AYT, if ^T is enabled, use that. Otherwise, * just send back "[Yes]". */ void recv_ayt(void) { if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) { (void) ioctl(pty, TIOCSIG, (char *)SIGINFO); return; } (void) output_data("\r\n[Yes]\r\n"); } void doeof(void) { init_termbuf(); #if defined(LINEMODE) && (VEOF == VMIN) if (!tty_isediting()) { extern char oldeofc; *pfrontp++ = oldeofc; return; } #endif *pfrontp++ = slctab[SLC_EOF].sptr ? (unsigned char)*slctab[SLC_EOF].sptr : '\004'; }