4.3BSD/usr/src/etc/telnetd.c
/*
* Copyright (c) 1983,1986 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1983 Regents of the University of California.\n\
All rights reserved.\n";
#endif not lint
#ifndef lint
static char sccsid[] = "@(#)telnetd.c 5.18 (Berkeley) 5/12/86";
#endif not lint
/*
* Telnet server.
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/telnet.h>
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <sgtty.h>
#include <netdb.h>
#include <syslog.h>
#include <ctype.h>
#define OPT_NO 0 /* won't do this option */
#define OPT_YES 1 /* will do this option */
#define OPT_YES_BUT_ALWAYS_LOOK 2
#define OPT_NO_BUT_ALWAYS_LOOK 3
char hisopts[256];
char myopts[256];
char doopt[] = { IAC, DO, '%', 'c', 0 };
char dont[] = { IAC, DONT, '%', 'c', 0 };
char will[] = { IAC, WILL, '%', 'c', 0 };
char wont[] = { IAC, WONT, '%', 'c', 0 };
/*
* I/O data buffers, pointers, and counters.
*/
char ptyibuf[BUFSIZ], *ptyip = ptyibuf;
char ptyobuf[BUFSIZ], *pfrontp = ptyobuf, *pbackp = ptyobuf;
char netibuf[BUFSIZ], *netip = netibuf;
#define NIACCUM(c) { *netip++ = c; \
ncc++; \
}
char netobuf[BUFSIZ], *nfrontp = netobuf, *nbackp = netobuf;
char *neturg = 0; /* one past last bye of urgent data */
/* the remote system seems to NOT be an old 4.2 */
int not42 = 1;
char BANNER1[] = "\r\n\r\n4.3 BSD UNIX (",
BANNER2[] = ")\r\n\r\0\r\n\r\0";
/* buffer for sub-options */
char subbuffer[100], *subpointer= subbuffer, *subend= subbuffer;
#define SB_CLEAR() subpointer = subbuffer;
#define SB_TERM() { subend = subpointer; SB_CLEAR(); }
#define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \
*subpointer++ = (c); \
}
#define SB_GET() ((*subpointer++)&0xff)
#define SB_EOF() (subpointer >= subend)
int pcc, ncc;
int pty, net;
int inter;
extern char **environ;
extern int errno;
char *line;
int SYNCHing = 0; /* we are in TELNET SYNCH mode */
/*
* The following are some clocks used to decide how to interpret
* the relationship between various variables.
*/
struct {
int
system, /* what the current time is */
echotoggle, /* last time user entered echo character */
modenegotiated, /* last time operating mode negotiated */
didnetreceive, /* last time we read data from network */
ttypeopt, /* ttype will/won't received */
ttypesubopt, /* ttype subopt is received */
getterminal, /* time started to get terminal information */
gotDM; /* when did we last see a data mark */
} clocks;
#define settimer(x) (clocks.x = ++clocks.system)
#define sequenceIs(x,y) (clocks.x < clocks.y)
main(argc, argv)
char *argv[];
{
struct sockaddr_in from;
int on = 1, fromlen;
#if defined(DEBUG)
{
int s, ns, foo;
struct servent *sp;
static struct sockaddr_in sin = { AF_INET };
sp = getservbyname("telnet", "tcp");
if (sp == 0) {
fprintf(stderr, "telnetd: tcp/telnet: unknown service\n");
exit(1);
}
sin.sin_port = sp->s_port;
argc--, argv++;
if (argc > 0) {
sin.sin_port = atoi(*argv);
sin.sin_port = htons((u_short)sin.sin_port);
}
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0) {
perror("telnetd: socket");;
exit(1);
}
if (bind(s, &sin, sizeof sin) < 0) {
perror("bind");
exit(1);
}
if (listen(s, 1) < 0) {
perror("listen");
exit(1);
}
foo = sizeof sin;
ns = accept(s, &sin, &foo);
if (ns < 0) {
perror("accept");
exit(1);
}
dup2(ns, 0);
close(s);
}
#endif /* defined(DEBUG) */
openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
fromlen = sizeof (from);
if (getpeername(0, &from, &fromlen) < 0) {
fprintf(stderr, "%s: ", argv[0]);
perror("getpeername");
_exit(1);
}
if (setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0) {
syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
}
doit(0, &from);
}
char *terminaltype = 0;
char *envinit[2];
int cleanup();
/*
* ttloop
*
* A small subroutine to flush the network output buffer, get some data
* from the network, and pass it through the telnet state machine. We
* also flush the pty input buffer (by dropping its data) if it becomes
* too full.
*/
void
ttloop()
{
if (nfrontp-nbackp) {
netflush();
}
ncc = read(net, netibuf, sizeof netibuf);
if (ncc < 0) {
syslog(LOG_INFO, "ttloop: read: %m\n");
exit(1);
} else if (ncc == 0) {
syslog(LOG_INFO, "ttloop: peer died: %m\n");
exit(1);
}
netip = netibuf;
telrcv(); /* state machine */
if (ncc > 0) {
pfrontp = pbackp = ptyobuf;
telrcv();
}
}
/*
* getterminaltype
*
* Ask the other end to send along its terminal type.
* Output is the variable terminaltype filled in.
*/
void
getterminaltype()
{
static char sbuf[] = { IAC, DO, TELOPT_TTYPE };
settimer(getterminal);
bcopy(sbuf, nfrontp, sizeof sbuf);
nfrontp += sizeof sbuf;
hisopts[TELOPT_TTYPE] = OPT_YES_BUT_ALWAYS_LOOK;
while (sequenceIs(ttypeopt, getterminal)) {
ttloop();
}
if (hisopts[TELOPT_TTYPE] == OPT_YES) {
static char sbbuf[] = { IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE };
bcopy(sbbuf, nfrontp, sizeof sbbuf);
nfrontp += sizeof sbbuf;
while (sequenceIs(ttypesubopt, getterminal)) {
ttloop();
}
}
}
/*
* Get a pty, scan input lines.
*/
doit(f, who)
int f;
struct sockaddr_in *who;
{
char *host, *inet_ntoa();
int i, p, t;
struct sgttyb b;
struct hostent *hp;
int c;
for (c = 'p'; c <= 's'; c++) {
struct stat stb;
line = "/dev/ptyXX";
line[strlen("/dev/pty")] = c;
line[strlen("/dev/ptyp")] = '0';
if (stat(line, &stb) < 0)
break;
for (i = 0; i < 16; i++) {
line[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
p = open(line, 2);
if (p > 0)
goto gotpty;
}
}
fatal(f, "All network ports in use");
/*NOTREACHED*/
gotpty:
dup2(f, 0);
line[strlen("/dev/")] = 't';
t = open("/dev/tty", O_RDWR);
if (t >= 0) {
ioctl(t, TIOCNOTTY, 0);
close(t);
}
t = open(line, O_RDWR);
if (t < 0)
fatalperror(f, line, errno);
ioctl(t, TIOCGETP, &b);
b.sg_flags = CRMOD|XTABS|ANYP;
ioctl(t, TIOCSETP, &b);
ioctl(p, TIOCGETP, &b);
b.sg_flags &= ~ECHO;
ioctl(p, TIOCSETP, &b);
hp = gethostbyaddr(&who->sin_addr, sizeof (struct in_addr),
who->sin_family);
if (hp)
host = hp->h_name;
else
host = inet_ntoa(who->sin_addr);
net = f;
pty = p;
/*
* get terminal type.
*/
getterminaltype();
if ((i = fork()) < 0)
fatalperror(f, "fork", errno);
if (i)
telnet(f, p);
close(f);
close(p);
dup2(t, 0);
dup2(t, 1);
dup2(t, 2);
close(t);
envinit[0] = terminaltype;
envinit[1] = 0;
environ = envinit;
/*
* -h : pass on name of host.
* WARNING: -h is accepted by login if and only if
* getuid() == 0.
* -p : don't clobber the environment (so terminal type stays set).
*/
execl("/bin/login", "login", "-h", host,
terminaltype ? "-p" : 0, 0);
fatalperror(f, "/bin/login", errno);
/*NOTREACHED*/
}
fatal(f, msg)
int f;
char *msg;
{
char buf[BUFSIZ];
(void) sprintf(buf, "telnetd: %s.\r\n", msg);
(void) write(f, buf, strlen(buf));
exit(1);
}
fatalperror(f, msg, errno)
int f;
char *msg;
int errno;
{
char buf[BUFSIZ];
extern char *sys_errlist[];
(void) sprintf(buf, "%s: %s\r\n", msg, sys_errlist[errno]);
fatal(f, buf);
}
/*
* Check a descriptor to see if out of band data exists on it.
*/
stilloob(s)
int s; /* socket number */
{
static struct timeval timeout = { 0 };
fd_set excepts;
int value;
do {
FD_ZERO(&excepts);
FD_SET(s, &excepts);
value = select(s+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
} while ((value == -1) && (errno == EINTR));
if (value < 0) {
fatalperror(pty, "select", errno);
}
if (FD_ISSET(s, &excepts)) {
return 1;
} else {
return 0;
}
}
/*
* Main loop. Select from pty and network, and
* hand data to telnet receiver finite state machine.
*/
telnet(f, p)
{
int on = 1;
char hostname[MAXHOSTNAMELEN];
ioctl(f, FIONBIO, &on);
ioctl(p, FIONBIO, &on);
#if defined(SO_OOBINLINE)
setsockopt(net, SOL_SOCKET, SO_OOBINLINE, &on, sizeof on);
#endif /* defined(SO_OOBINLINE) */
signal(SIGTSTP, SIG_IGN);
signal(SIGCHLD, cleanup);
setpgrp(0, 0);
/*
* Request to do remote echo and to suppress go ahead.
*/
if (!myopts[TELOPT_ECHO]) {
dooption(TELOPT_ECHO);
}
if (!myopts[TELOPT_SGA]) {
dooption(TELOPT_SGA);
}
/*
* 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).
*/
sprintf(nfrontp, doopt, TELOPT_ECHO);
nfrontp += sizeof doopt-2;
hisopts[TELOPT_ECHO] = OPT_YES_BUT_ALWAYS_LOOK;
/*
* Show banner that getty never gave.
*
* The banner includes some null's (for TELNET CR disambiguation),
* so we have to be somewhat complicated.
*/
gethostname(hostname, sizeof (hostname));
bcopy(BANNER1, nfrontp, sizeof BANNER1 -1);
nfrontp += sizeof BANNER1 - 1;
bcopy(hostname, nfrontp, strlen(hostname));
nfrontp += strlen(hostname);
bcopy(BANNER2, nfrontp, sizeof BANNER2 -1);
nfrontp += sizeof BANNER2 - 1;
/*
* Call telrcv() once to pick up anything received during
* terminal type negotiation.
*/
telrcv();
for (;;) {
fd_set ibits, obits, xbits;
register 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(16, &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;
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;
}
}
/*
* Something to read from the pty...
*/
if (FD_ISSET(p, &ibits)) {
pcc = read(p, ptyibuf, BUFSIZ);
if (pcc < 0 && errno == EWOULDBLOCK)
pcc = 0;
else {
if (pcc <= 0)
break;
ptyip = ptyibuf;
}
}
while (pcc > 0) {
if ((&netobuf[BUFSIZ] - nfrontp) < 2)
break;
c = *ptyip++ & 0377, pcc--;
if (c == IAC)
*nfrontp++ = c;
*nfrontp++ = c;
if (c == '\r') {
if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
*nfrontp++ = *ptyip++ & 0377;
pcc--;
} else
*nfrontp++ = '\0';
}
}
if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
netflush();
if (ncc > 0)
telrcv();
if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
ptyflush();
}
cleanup();
}
/*
* State for recv fsm
*/
#define TS_DATA 0 /* base state */
#define TS_IAC 1 /* look for double IAC's */
#define TS_CR 2 /* CR-LF ->'s CR */
#define TS_SB 3 /* throw away begin's... */
#define TS_SE 4 /* ...end's (suboption negotiation) */
#define TS_WILL 5 /* will option negotiation */
#define TS_WONT 6 /* wont " */
#define TS_DO 7 /* do " */
#define TS_DONT 8 /* dont " */
telrcv()
{
register int c;
static int state = TS_DATA;
while (ncc > 0) {
if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
return;
c = *netip++ & 0377, ncc--;
switch (state) {
case TS_CR:
state = TS_DATA;
if ((c == 0) || (c == '\n')) {
break;
}
/* FALL THROUGH */
case TS_DATA:
if (c == IAC) {
state = TS_IAC;
break;
}
if (inter > 0)
break;
/*
* We map \r\n ==> \n, since \r\n says
* that we want to be in column 1 of the next
* printable line, and \n is the standard
* unix way of saying that (\r is only good
* if CRMOD is set, which it normally is).
*/
if ((myopts[TELOPT_BINARY] == OPT_NO) && c == '\r') {
if ((ncc > 0) && ('\n' == *netip)) {
netip++; ncc--;
c = '\n';
} else {
state = TS_CR;
}
}
*pfrontp++ = c;
break;
case TS_IAC:
switch (c) {
/*
* Send the process on the pty side an
* interrupt. Do this with a NULL or
* interrupt char; depending on the tty mode.
*/
case IP:
interrupt();
break;
case BREAK:
sendbrk();
break;
/*
* Are You There?
*/
case AYT:
strcpy(nfrontp, "\r\n[Yes]\r\n");
nfrontp += 9;
break;
/*
* Abort Output
*/
case AO: {
struct ltchars tmpltc;
ptyflush(); /* half-hearted */
ioctl(pty, TIOCGLTC, &tmpltc);
if (tmpltc.t_flushc != '\377') {
*pfrontp++ = tmpltc.t_flushc;
}
netclear(); /* clear buffer back */
*nfrontp++ = IAC;
*nfrontp++ = DM;
neturg = nfrontp-1; /* off by one XXX */
break;
}
/*
* Erase Character and
* Erase Line
*/
case EC:
case EL: {
struct sgttyb b;
char ch;
ptyflush(); /* half-hearted */
ioctl(pty, TIOCGETP, &b);
ch = (c == EC) ?
b.sg_erase : b.sg_kill;
if (ch != '\377') {
*pfrontp++ = ch;
}
break;
}
/*
* Check for urgent data...
*/
case DM:
SYNCHing = stilloob(net);
settimer(gotDM);
break;
/*
* Begin option subnegotiation...
*/
case SB:
state = TS_SB;
continue;
case WILL:
state = TS_WILL;
continue;
case WONT:
state = TS_WONT;
continue;
case DO:
state = TS_DO;
continue;
case DONT:
state = TS_DONT;
continue;
case IAC:
*pfrontp++ = c;
break;
}
state = TS_DATA;
break;
case TS_SB:
if (c == IAC) {
state = TS_SE;
} else {
SB_ACCUM(c);
}
break;
case TS_SE:
if (c != SE) {
if (c != IAC) {
SB_ACCUM(IAC);
}
SB_ACCUM(c);
state = TS_SB;
} else {
SB_TERM();
suboption(); /* handle sub-option */
state = TS_DATA;
}
break;
case TS_WILL:
if (hisopts[c] != OPT_YES)
willoption(c);
state = TS_DATA;
continue;
case TS_WONT:
if (hisopts[c] != OPT_NO)
wontoption(c);
state = TS_DATA;
continue;
case TS_DO:
if (myopts[c] != OPT_YES)
dooption(c);
state = TS_DATA;
continue;
case TS_DONT:
if (myopts[c] != OPT_NO) {
dontoption(c);
}
state = TS_DATA;
continue;
default:
syslog(LOG_ERR, "telnetd: panic state=%d\n", state);
printf("telnetd: panic state=%d\n", state);
exit(1);
}
}
}
willoption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_BINARY:
mode(RAW, 0);
fmt = doopt;
break;
case TELOPT_ECHO:
not42 = 0; /* looks like a 4.2 system */
/*
* Now, in a 4.2 system, to break them out of ECHOing
* (to the terminal) mode, we need to send a "WILL ECHO".
* Kludge upon kludge!
*/
if (myopts[TELOPT_ECHO] == OPT_YES) {
dooption(TELOPT_ECHO);
}
fmt = dont;
break;
case TELOPT_TTYPE:
settimer(ttypeopt);
if (hisopts[TELOPT_TTYPE] == OPT_YES_BUT_ALWAYS_LOOK) {
hisopts[TELOPT_TTYPE] = OPT_YES;
return;
}
fmt = doopt;
break;
case TELOPT_SGA:
fmt = doopt;
break;
case TELOPT_TM:
fmt = dont;
break;
default:
fmt = dont;
break;
}
if (fmt == doopt) {
hisopts[option] = OPT_YES;
} else {
hisopts[option] = OPT_NO;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof (dont) - 2;
}
wontoption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_ECHO:
not42 = 1; /* doesn't seem to be a 4.2 system */
break;
case TELOPT_BINARY:
mode(0, RAW);
break;
case TELOPT_TTYPE:
settimer(ttypeopt);
break;
}
fmt = dont;
hisopts[option] = OPT_NO;
sprintf(nfrontp, fmt, option);
nfrontp += sizeof (doopt) - 2;
}
dooption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_TM:
fmt = wont;
break;
case TELOPT_ECHO:
mode(ECHO|CRMOD, 0);
fmt = will;
break;
case TELOPT_BINARY:
mode(RAW, 0);
fmt = will;
break;
case TELOPT_SGA:
fmt = will;
break;
default:
fmt = wont;
break;
}
if (fmt == will) {
myopts[option] = OPT_YES;
} else {
myopts[option] = OPT_NO;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof (doopt) - 2;
}
dontoption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_ECHO: /* we should stop echoing */
mode(0, ECHO|CRMOD);
fmt = wont;
break;
default:
fmt = wont;
break;
}
if (fmt = wont) {
myopts[option] = OPT_NO;
} else {
myopts[option] = OPT_YES;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof (wont) - 2;
}
/*
* suboption()
*
* Look at the sub-option buffer, and try to be helpful to the other
* side.
*
* Currently we recognize:
*
* Terminal type is
*/
suboption()
{
switch (SB_GET()) {
case TELOPT_TTYPE: { /* Yaaaay! */
static char terminalname[5+41] = "TERM=";
settimer(ttypesubopt);
if (SB_GET() != TELQUAL_IS) {
return; /* ??? XXX but, this is the most robust */
}
terminaltype = terminalname+strlen(terminalname);
while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
!SB_EOF()) {
register int c;
c = SB_GET();
if (isupper(c)) {
c = tolower(c);
}
*terminaltype++ = c; /* accumulate name */
}
*terminaltype = 0;
terminaltype = terminalname;
break;
}
default:
;
}
}
mode(on, off)
int on, off;
{
struct sgttyb b;
ptyflush();
ioctl(pty, TIOCGETP, &b);
b.sg_flags |= on;
b.sg_flags &= ~off;
ioctl(pty, TIOCSETP, &b);
}
/*
* Send interrupt to process on other side of pty.
* If it is in raw mode, just write NULL;
* otherwise, write intr char.
*/
interrupt()
{
struct sgttyb b;
struct tchars tchars;
ptyflush(); /* half-hearted */
ioctl(pty, TIOCGETP, &b);
if (b.sg_flags & RAW) {
*pfrontp++ = '\0';
return;
}
*pfrontp++ = ioctl(pty, TIOCGETC, &tchars) < 0 ?
'\177' : tchars.t_intrc;
}
/*
* Send quit to process on other side of pty.
* If it is in raw mode, just write NULL;
* otherwise, write quit char.
*/
sendbrk()
{
struct sgttyb b;
struct tchars tchars;
ptyflush(); /* half-hearted */
ioctl(pty, TIOCGETP, &b);
if (b.sg_flags & RAW) {
*pfrontp++ = '\0';
return;
}
*pfrontp++ = ioctl(pty, TIOCGETC, &tchars) < 0 ?
'\034' : tchars.t_quitc;
}
ptyflush()
{
int n;
if ((n = pfrontp - pbackp) > 0)
n = write(pty, pbackp, n);
if (n < 0)
return;
pbackp += n;
if (pbackp == pfrontp)
pbackp = pfrontp = ptyobuf;
}
/*
* nextitem()
*
* Return the address of the next "item" in the TELNET data
* stream. This will be the address of the next character if
* the current address is a user data character, or it will
* be the address of the character following the TELNET command
* if the current address is a TELNET IAC ("I Am a Command")
* character.
*/
char *
nextitem(current)
char *current;
{
if ((*current&0xff) != IAC) {
return current+1;
}
switch (*(current+1)&0xff) {
case DO:
case DONT:
case WILL:
case WONT:
return current+3;
case SB: /* loop forever looking for the SE */
{
register char *look = current+2;
for (;;) {
if ((*look++&0xff) == IAC) {
if ((*look++&0xff) == SE) {
return look;
}
}
}
}
default:
return current+2;
}
}
/*
* netclear()
*
* We are about to do a TELNET SYNCH operation. Clear
* the path to the network.
*
* Things are a bit tricky since we may have sent the first
* byte or so of a previous TELNET command into the network.
* So, we have to scan the network buffer from the beginning
* until we are up to where we want to be.
*
* A side effect of what we do, just to keep things
* simple, is to clear the urgent data pointer. The principal
* caller should be setting the urgent data pointer AFTER calling
* us in any case.
*/
netclear()
{
register char *thisitem, *next;
char *good;
#define wewant(p) ((nfrontp > p) && ((*p&0xff) == IAC) && \
((*(p+1)&0xff) != EC) && ((*(p+1)&0xff) != EL))
thisitem = netobuf;
while ((next = nextitem(thisitem)) <= nbackp) {
thisitem = next;
}
/* Now, thisitem is first before/at boundary. */
good = netobuf; /* where the good bytes go */
while (nfrontp > thisitem) {
if (wewant(thisitem)) {
int length;
next = thisitem;
do {
next = nextitem(next);
} while (wewant(next) && (nfrontp > next));
length = next-thisitem;
bcopy(thisitem, good, length);
good += length;
thisitem = next;
} else {
thisitem = nextitem(thisitem);
}
}
nbackp = netobuf;
nfrontp = good; /* next byte to be sent */
neturg = 0;
}
/*
* netflush
* Send as much data as possible to the network,
* handling requests for urgent data.
*/
netflush()
{
int n;
if ((n = nfrontp - nbackp) > 0) {
/*
* if no urgent data, or if the other side appears to be an
* old 4.2 client (and thus unable to survive TCP urgent data),
* write the entire buffer in non-OOB mode.
*/
if ((neturg == 0) || (not42 == 0)) {
n = write(net, nbackp, n); /* normal write */
} else {
n = neturg - nbackp;
/*
* In 4.2 (and 4.3) systems, there is some question about
* what byte in a sendOOB operation is the "OOB" data.
* To make ourselves compatible, we only send ONE byte
* out of band, the one WE THINK should be OOB (though
* we really have more the TCP philosophy of urgent data
* rather than the Unix philosophy of OOB data).
*/
if (n > 1) {
n = send(net, nbackp, n-1, 0); /* send URGENT all by itself */
} else {
n = send(net, nbackp, n, MSG_OOB); /* URGENT data */
}
}
}
if (n < 0) {
if (errno == EWOULDBLOCK)
return;
/* should blow this guy away... */
return;
}
nbackp += n;
if (nbackp >= neturg) {
neturg = 0;
}
if (nbackp == nfrontp) {
nbackp = nfrontp = netobuf;
}
}
cleanup()
{
rmut();
vhangup(); /* XXX */
shutdown(net, 2);
exit(1);
}
#include <utmp.h>
struct utmp wtmp;
char wtmpf[] = "/usr/adm/wtmp";
char utmpf[] = "/etc/utmp";
#define SCPYN(a, b) strncpy(a, b, sizeof(a))
#define SCMPN(a, b) strncmp(a, b, sizeof(a))
rmut()
{
register f;
int found = 0;
struct utmp *u, *utmp;
int nutmp;
struct stat statbf;
f = open(utmpf, O_RDWR);
if (f >= 0) {
fstat(f, &statbf);
utmp = (struct utmp *)malloc(statbf.st_size);
if (!utmp)
syslog(LOG_ERR, "utmp malloc failed");
if (statbf.st_size && utmp) {
nutmp = read(f, utmp, statbf.st_size);
nutmp /= sizeof(struct utmp);
for (u = utmp ; u < &utmp[nutmp] ; u++) {
if (SCMPN(u->ut_line, line+5) ||
u->ut_name[0]==0)
continue;
lseek(f, ((long)u)-((long)utmp), L_SET);
SCPYN(u->ut_name, "");
SCPYN(u->ut_host, "");
time(&u->ut_time);
write(f, (char *)u, sizeof(wtmp));
found++;
}
}
close(f);
}
if (found) {
f = open(wtmpf, O_WRONLY|O_APPEND);
if (f >= 0) {
SCPYN(wtmp.ut_line, line+5);
SCPYN(wtmp.ut_name, "");
SCPYN(wtmp.ut_host, "");
time(&wtmp.ut_time);
write(f, (char *)&wtmp, sizeof(wtmp));
close(f);
}
}
chmod(line, 0666);
chown(line, 0, 0);
line[strlen("/dev/")] = 'p';
chmod(line, 0666);
chown(line, 0, 0);
}