/
telnetd.c
1114 lines (997 loc) · 27.6 KB
/
telnetd.c
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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*
* @(#)telnetd.c 8.4 (Berkeley) 5/30/95
* $FreeBSD: src/libexec/telnetd/telnetd.c,v 1.22.2.8 2002/04/13 11:07:12 markm Exp $
* $DragonFly: src/libexec/telnetd/telnetd.c,v 1.3 2006/01/12 13:43:10 corecode Exp $
*/
#include "telnetd.h"
#include "pathnames.h"
#include <sys/mman.h>
#include <err.h>
#include <libutil.h>
#include <paths.h>
#include <termcap.h>
#include <utmp.h>
#include <arpa/inet.h>
#include <libtelnet/misc.h>
char remote_hostname[MAXHOSTNAMELEN];
size_t utmp_len = sizeof(remote_hostname) - 1;
int registerd_host_only = 0;
/*
* I/O data buffers,
* pointers, and counters.
*/
char ptyibuf[BUFSIZ], *ptyip = ptyibuf;
char ptyibuf2[BUFSIZ];
int readstream(int, char *, int);
void doit(struct sockaddr *);
int terminaltypeok(char *);
int hostinfo = 1; /* do we print login banner? */
int debug = 0;
int keepalive = 1;
const char *altlogin;
void doit(struct sockaddr *);
int terminaltypeok(char *);
void startslave(char *, int, char *);
extern void usage(void);
static void _gettermname(void);
/*
* 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', ':', 'h', 'k', 'n', 'p', ':', 'S', ':', 'u', ':', 'U',
'4', '6',
#ifdef BFTPDAEMON
'B',
#endif
#ifdef DIAGNOSTICS
'D', ':',
#endif
#ifdef LINEMODE
'l',
#endif
'\0'
};
int family = AF_INET;
#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 256
#endif /* MAXHOSTNAMELEN */
char *hostname;
char host_name[MAXHOSTNAMELEN];
extern void telnet(int, int, char *);
int level;
char user_name[256];
int
main(int argc, char *argv[])
{
struct sockaddr_storage from;
int on = 1, fromlen;
int ch;
#if defined(IPPROTO_IP) && defined(IP_TOS)
int tos = -1;
#endif
pfrontp = pbackp = ptyobuf;
netip = netibuf;
nfrontp = nbackp = netobuf;
/*
* This initialization causes linemode to default to a configuration
* that works on all telnet clients, including the FreeBSD client.
* This is not quite the same as the telnet client issuing a "mode
* character" command, but has most of the same benefits, and is
* preferable since some clients (like usofts) don't have the
* mode character command anyway and linemode breaks things.
* The most notable symptom of fix is that csh "set filec" operations
* like <ESC> (filename completion) and ^D (choices) keys now work
* in telnet sessions and can be used more than once on the same line.
* CR/LF handling is also corrected in some termio modes. This
* change resolves problem reports bin/771 and bin/1037.
*/
linemode=1; /*Default to mode that works on bulk of clients*/
while ((ch = getopt(argc, argv, valid_opts)) != -1) {
switch(ch) {
#ifdef BFTPDAEMON
case 'B':
bftpd++;
break;
#endif /* BFTPDAEMON */
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 */
case 'h':
hostinfo = 0;
break;
#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;
case 'p':
altlogin = optarg;
break;
case 'S':
#ifdef HAS_GETTOS
if ((tos = parsetos(optarg, "tcp")) < 0)
warnx("%s%s%s",
"bad TOS argument '", optarg,
"'; will try to use default TOS");
#else
warnx("TOS option unavailable; -S flag not supported");
#endif
break;
case 'u':
utmp_len = (size_t)atoi(optarg);
if (utmp_len >= sizeof(remote_hostname))
utmp_len = sizeof(remote_hostname) - 1;
break;
case 'U':
registerd_host_only = 1;
break;
case '4':
family = AF_INET;
break;
#ifdef INET6
case '6':
family = AF_INET6;
break;
#endif
default:
warnx("%c: unknown option", ch);
/* FALLTHROUGH */
case '?':
usage();
/* NOTREACHED */
}
}
argc -= optind;
argv += optind;
if (debug) {
int s, ns, foo, error;
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) {
errx(1, "tcp/%s: %s\n", service, gai_strerror(error));
if (error == EAI_SYSTEM)
errx(1, "tcp/%s: %s\n", service, strerror(errno));
usage();
}
s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (s < 0)
err(1, "socket");
(void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
(char *)&on, sizeof(on));
if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
err(1, "bind");
if (listen(s, 1) < 0)
err(1, "listen");
foo = res->ai_addrlen;
ns = accept(s, res->ai_addr, &foo);
if (ns < 0)
err(1, "accept");
(void) dup2(ns, 0);
(void) close(ns);
(void) close(s);
#ifdef convex
} else if (argc == 1) {
; /* VOID*/ /* Just ignore the host/port name */
#endif
} else if (argc > 0) {
usage();
/* NOT REACHED */
}
openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
fromlen = sizeof (from);
if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
warn("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 (from.ss_family == AF_INET) {
# if defined(HAS_GETTOS)
struct tosent *tp;
if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
tos = tp->t_tos;
# endif
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 */
return(0);
} /* end of main */
void
usage()
{
fprintf(stderr, "usage: telnetd");
#ifdef BFTPDAEMON
fprintf(stderr, " [-B]");
#endif
fprintf(stderr, " [-debug]");
#ifdef DIAGNOSTICS
fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
#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 HAS_GETTOS
fprintf(stderr, " [-S tos]");
#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
};
#define undef2 __unused
static int
getterminaltype(char *name undef2)
{
int retval = -1;
settimer(baseline);
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 (
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(sb, sizeof sb);
DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
}
if (his_state_is_will(TELOPT_XDISPLOC)) {
static unsigned char sb[] =
{ IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };
output_datalen(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(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(sb, sizeof sb);
DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
}
if (his_state_is_will(TELOPT_TTYPE)) {
output_datalen(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) strncpy(first, terminaltype, sizeof(first)-1);
first[sizeof(first)-1] = '\0';
for(;;) {
/*
* Save the unknown name, and request the next name.
*/
(void) strncpy(last, terminaltype, sizeof(last)-1);
last[sizeof(last)-1] = '\0';
_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) strncpy(terminaltype, first, sizeof(terminaltype)-1);
terminaltype[sizeof(terminaltype)-1] = '\0';
}
break;
}
}
}
}
return(retval);
} /* end of getterminaltype */
static 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(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];
if (terminaltype == NULL)
return(1);
/*
* 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);
}
/*
* Get a pty, scan input lines.
*/
void
doit(struct sockaddr *who)
{
int err_; /* XXX */
int ptynum;
/*
* Find an available pty to use.
*/
#ifndef convex
pty = getpty(&ptynum);
if (pty < 0)
fatal(net, "All network ports in use");
#else
for (;;) {
char *lp;
if ((lp = getpty()) == NULL)
fatal(net, "Out of ptys");
if ((pty = open(lp, 2)) >= 0) {
strlcpy(line,lp,sizeof(line));
line[5] = 't';
break;
}
}
#endif
/* get name of connected client */
if (realhostname_sa(remote_hostname, sizeof(remote_hostname) - 1,
who, who->sa_len) == HOSTNAME_INVALIDADDR && registerd_host_only)
fatal(net, "Couldn't resolve your address into a host name.\r\n\
Please contact your net administrator");
remote_hostname[sizeof(remote_hostname) - 1] = '\0';
trimdomain(remote_hostname, UT_HOSTSIZE);
if (!isdigit(remote_hostname[0]) && strlen(remote_hostname) > utmp_len)
err_ = getnameinfo(who, who->sa_len, remote_hostname,
sizeof(remote_hostname), NULL, 0,
NI_NUMERICHOST|NI_WITHSCOPEID);
/* XXX: do 'err_' check */
(void) gethostname(host_name, sizeof(host_name) - 1);
host_name[sizeof(host_name) - 1] = '\0';
hostname = host_name;
init_env();
/*
* get terminal type.
*/
*user_name = 0;
level = getterminaltype(user_name);
if (setenv("TERM", terminaltype ? terminaltype : "network", 1) == -1)
syslog(LOG_ERR, "setenv: cannot set TERM=%s: %m", terminaltype ? terminaltype : "network");
telnet(net, pty, remote_hostname); /* begin server process */
/*NOTREACHED*/
} /* end of doit */
/*
* Main loop. Select from pty and network, and
* hand data to telnet receiver finite state machine.
*/
void
telnet(int f, int p, char *host)
{
int on = 1;
#define TABBUFSIZ 512
char defent[TABBUFSIZ];
char defstrs[TABBUFSIZ];
#undef TABBUFSIZ
char *HE;
char *HN;
char *IM;
int nfd;
/*
* Initialize the slc mapping table.
*/
get_slc_defaults();
/*
* Do some tests where it is desireable 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);
#if defined(SO_OOBINLINE)
(void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
(char *)&on, sizeof on);
#endif /* defined(SO_OOBINLINE) */
#ifdef SIGTSTP
(void) signal(SIGTSTP, SIG_IGN);
#endif
#ifdef SIGTTOU
/*
* Ignoring SIGTTOU keeps the kernel from blocking us
* in ttioct() in /sys/tty.c.
*/
(void) signal(SIGTTOU, SIG_IGN);
#endif
(void) signal(SIGCHLD, cleanup);
#ifdef TIOCNOTTY
{
int t;
t = open(_PATH_TTY, O_RDWR);
if (t >= 0) {
(void) ioctl(t, TIOCNOTTY, (char *)0);
(void) close(t);
}
}
#endif
/*
* 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, "default") == 1) {
char *cp=defstrs;
HE = Getstr("he", &cp);
HN = Getstr("hn", &cp);
IM = Getstr("im", &cp);
if (HN && *HN)
(void) strlcpy(host_name, HN, sizeof(host_name));
if (IM == 0)
IM = strdup("");
} else {
IM = strdup(DEFAULT_IM);
HE = 0;
}
edithost(HE, host_name);
if (hostinfo && *IM)
putf(IM, ptyibuf2);
if (pcc)
(void) strncat(ptyibuf2, 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"));
/*
* Startup the login process on the slave side of the terminal
* now. We delay this until here to insure option negotiation
* is complete.
*/
startslave(host, level, user_name);
nfd = ((f > p) ? f : p) + 1;
for (;;) {
fd_set ibits, obits, xbits;
int c;
if (ncc < 0 && pcc < 0)
break;
FD_ZERO(&ibits);
FD_ZERO(&obits);
FD_ZERO(&xbits);
/*
* Never look for input if there's still
* stuff in the corresponding output buffer
*/
if (nfrontp - nbackp || pcc > 0) {
FD_SET(f, &obits);
} else {
FD_SET(p, &ibits);
}
if (pfrontp - pbackp || ncc > 0) {
FD_SET(p, &obits);
} else {
FD_SET(f, &ibits);
}
if (!SYNCHing) {
FD_SET(f, &xbits);
}
if ((c = select(nfd, &ibits, &obits, &xbits,
(struct timeval *)0)) < 1) {
if (c == -1) {
if (errno == EINTR) {
continue;
}
}
sleep(5);
continue;
}
/*
* Any urgent data?
*/
if (FD_ISSET(net, &xbits)) {
SYNCHing = 1;
}
/*
* Something to read from the network...
*/
if (FD_ISSET(net, &ibits)) {
#if !defined(SO_OOBINLINE)
/*
* In 4.2 (and 4.3 beta) systems, the
* OOB indication and data handling in the kernel
* is such that if two separate TCP Urgent requests
* come in, one byte of TCP data will be overlaid.
* This is fatal for Telnet, but we try to live
* with it.
*
* In addition, in 4.2 (and...), a special protocol
* is needed to pick up the TCP Urgent data in
* the correct sequence.
*
* What we do is: if we think we are in urgent
* mode, we look to see if we are "at the mark".
* If we are, we do an OOB receive. If we run
* this twice, we will do the OOB receive twice,
* but the second will fail, since the second
* time we were "at the mark", but there wasn't
* any data there (the kernel doesn't reset
* "at the mark" until we do a normal read).
* Once we've read the OOB data, we go ahead
* and do normal reads.
*
* There is also another problem, which is that
* since the OOB byte we read doesn't put us
* out of OOB state, and since that byte is most
* likely the TELNET DM (data mark), we would
* stay in the TELNET SYNCH (SYNCHing) state.
* So, clocks to the rescue. If we've "just"
* received a DM, then we test for the
* presence of OOB data when the receive OOB
* fails (and AFTER we did the normal mode read
* to clear "at the mark").
*/
if (SYNCHing) {
int atmark;
(void) ioctl(net, SIOCATMARK, (char *)&atmark);
if (atmark) {
ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
if ((ncc == -1) && (errno == EINVAL)) {
ncc = read(net, netibuf, sizeof (netibuf));
if (sequenceIs(didnetreceive, gotDM)) {
SYNCHing = stilloob(net);
}
}
} else {
ncc = read(net, netibuf, sizeof (netibuf));
}
} else {
ncc = read(net, netibuf, sizeof (netibuf));
}
settimer(didnetreceive);
#else /* !defined(SO_OOBINLINE)) */
ncc = read(net, netibuf, sizeof (netibuf));
#endif /* !defined(SO_OOBINLINE)) */
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 (FD_ISSET(p, &ibits)) {
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 ||
#ifdef EAGAIN
errno == EAGAIN ||
#endif
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 */
#ifndef NO_URGENT
/*
* 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));
#endif
}
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;
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;
}
}