[unix-history] / usr / src / libexec / telnetd / telnetd.c

#ifndef lint
static char sccsid[] = "@(#)telnetd.c	4.21 83/05/24";
#endif

/*
 * Stripped-down telnet server.
 */
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/telnet.h>

#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <sgtty.h>
#include <wait.h>
#include <netdb.h>
#include <getty.h>

#define	BELL		'\07'

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;
char	netobuf[BUFSIZ], *nfrontp = netobuf, *nbackp = netobuf;
int	pcc, ncc;

int	pty, net;
int	inter;
int	reapchild();
extern	int errno;
char	line[] = "/dev/ptyp0";

struct	sockaddr_in sin = { AF_INET };

main(argc, argv)
	char *argv[];
{
	int s, pid, options;
	struct servent *sp;

	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 && !strcmp(*argv, "-d")) {
		options |= SO_DEBUG;
		argc--, argv++;
	}
	if (argc > 0) {
		sin.sin_port = atoi(*argv);
		if (sin.sin_port <= 0) {
			fprintf(stderr, "telnetd: %s: bad port #\n", *argv);
			exit(1);
		}
		sin.sin_port = htons((u_short)sin.sin_port);
	}
#ifndef DEBUG
	if (fork())
		exit(0);
	for (s = 0; s < 10; s++)
		(void) close(s);
	(void) open("/", 0);
	(void) dup2(0, 1);
	(void) dup2(0, 2);
	{ int tt = open("/dev/tty", 2);
	  if (tt > 0) {
		ioctl(tt, TIOCNOTTY, 0);
		close(tt);
	  }
	}
#endif
again:
	s = socket(AF_INET, SOCK_STREAM, 0, 0);
	if (s < 0) {
		perror("telnetd: socket");;
		sleep(5);
		goto again;
	}
	if (options & SO_DEBUG)
		if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
			perror("telnetd: setsockopt (SO_DEBUG)");
	if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
		perror("telnetd: setsockopt (SO_KEEPALIVE)");
	while (bind(s, (caddr_t)&sin, sizeof (sin), 0) < 0) {
		perror("telnetd: bind");
		sleep(5);
	}
	sigset(SIGCHLD, reapchild);
	listen(s, 10);
	for (;;) {
		struct sockaddr_in from;
		int s2, fromlen = sizeof (from);

		s2 = accept(s, (caddr_t)&from, &fromlen);
		if (s2 < 0) {
			if (errno == EINTR)
				continue;
			perror("telnetd: accept");
			sleep(1);
			continue;
		}
		if ((pid = fork()) < 0)
			printf("Out of processes\n");
		else if (pid == 0) {
			signal(SIGCHLD, SIG_IGN);
			doit(s2, &from);
		}
		close(s2);
	}
	/*NOTREACHED*/
}

reapchild()
{
	union wait status;

	while (wait3(&status, WNOHANG, 0) > 0)
		;
}

int	cleanup();

/*
 * Get a pty, scan input lines.
 */
doit(f, who)
	int f;
	struct sockaddr_in *who;
{
	char *cp = line, *host, *ntoa();
	int i, p, cc, t;
	struct sgttyb b;
	struct hostent *hp;

	for (i = 0; i < 16; i++) {
		cp[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
		p = open(cp, 2);
		if (p > 0)
			goto gotpty;
	}
	fatal(f, "All network ports in use");
	/*NOTREACHED*/
gotpty:
	dup2(f, 0);
	cp[strlen("/dev/")] = 't';
	t = open("/dev/tty", 2);
	if (t >= 0) {
		ioctl(t, TIOCNOTTY, 0);
		close(t);
	}
	t = open(cp, 2);
	if (t < 0)
		fatalperror(f, cp, 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 = ntoa(who->sin_addr);
	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);
	execl("/bin/login", "login", "-h", host, 0);
	fatalperror(f, "/bin/login", errno);
	/*NOTREACHED*/
}

fatal(f, msg)
	int f;
	char *msg;
{
	char buf[BUFSIZ];

	(void) sprintf(buf, "telnetd: %s.\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", msg, sys_errlist[errno]);
	fatal(f, buf);
}

/*
 * Main loop.  Select from pty and network, and
 * hand data to telnet receiver finite state machine.
 */
telnet(f, p)
{
	int on = 1;
	char hostname[32];

	net = f, pty = p;
	ioctl(f, FIONBIO, &on);
	ioctl(p, FIONBIO, &on);
	signal(SIGTSTP, SIG_IGN);
	sigset(SIGCHLD, cleanup);

	/*
	 * Request to do remote echo.
	 */
	dooption(TELOPT_ECHO);
	myopts[TELOPT_ECHO] = 1;
	/*
	 * Show banner that getty never gave.
	 */
	gethostname(hostname, sizeof (hostname));
	sprintf(nfrontp, BANNER, hostname, "");
	nfrontp += strlen(nfrontp);
	for (;;) {
		int ibits = 0, obits = 0;
		register int c;

		/*
		 * Never look for input if there's still
		 * stuff in the corresponding output buffer
		 */
		if (nfrontp - nbackp)
			obits |= (1 << f);
		else
			ibits |= (1 << p);
		if (pfrontp - pbackp)
			obits |= (1 << p);
		else
			ibits |= (1 << f);
		if (ncc < 0 && pcc < 0)
			break;
		select(16, &ibits, &obits, 0, 0);
		if (ibits == 0 && obits == 0) {
			sleep(5);
			continue;
		}

		/*
		 * Something to read from the network...
		 */
		if (ibits & (1 << f)) {
			ncc = read(f, netibuf, BUFSIZ);
			if (ncc < 0 && errno == EWOULDBLOCK)
				ncc = 0;
			else {
				if (ncc <= 0)
					break;
				netip = netibuf;
			}
		}

		/*
		 * Something to read from the pty...
		 */
		if (ibits & (1 << p)) {
			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 ((obits & (1 << f)) && (nfrontp - nbackp) > 0)
			netflush();
		if (ncc > 0)
			telrcv();
		if ((obits & (1 << p)) && (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_BEGINNEG	3	/* throw away begin's... */
#define	TS_ENDNEG	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;
	struct sgttyb b;

	while (ncc > 0) {
		if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
			return;
		c = *netip++ & 0377, ncc--;
		switch (state) {

		case TS_DATA:
			if (c == IAC) {
				state = TS_IAC;
				break;
			}
			if (inter > 0)
				break;
			*pfrontp++ = c;
			if (!myopts[TELOPT_BINARY] && c == '\r')
				state = TS_CR;
			break;

		case TS_CR:
			if (c && c != '\n')
				*pfrontp++ = c;
			state = TS_DATA;
			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 BREAK:
			case IP:
				interrupt();
				break;

			/*
			 * Are You There?
			 */
			case AYT:
				*pfrontp++ = BELL;
				break;

			/*
			 * Erase Character and
			 * Erase Line
			 */
			case EC:
			case EL:
				ptyflush();	/* half-hearted */
				ioctl(pty, TIOCGETP, &b);
				*pfrontp++ = (c == EC) ?
					b.sg_erase : b.sg_kill;
				break;

			/*
			 * Check for urgent data...
			 */
			case DM:
				break;

			/*
			 * Begin option subnegotiation...
			 */
			case SB:
				state = TS_BEGINNEG;
				continue;

			case WILL:
			case WONT:
			case DO:
			case DONT:
				state = TS_WILL + (c - WILL);
				continue;

			case IAC:
				*pfrontp++ = c;
				break;
			}
			state = TS_DATA;
			break;

		case TS_BEGINNEG:
			if (c == IAC)
				state = TS_ENDNEG;
			break;

		case TS_ENDNEG:
			state = c == SE ? TS_DATA : TS_BEGINNEG;
			break;

		case TS_WILL:
			if (!hisopts[c])
				willoption(c);
			state = TS_DATA;
			continue;

		case TS_WONT:
			if (hisopts[c])
				wontoption(c);
			state = TS_DATA;
			continue;

		case TS_DO:
			if (!myopts[c])
				dooption(c);
			state = TS_DATA;
			continue;

		case TS_DONT:
			if (myopts[c]) {
				myopts[c] = 0;
				sprintf(nfrontp, wont, c);
				nfrontp += sizeof (wont) - 2;
			}
			state = TS_DATA;
			continue;

		default:
			printf("telnetd: panic state=%d\n", state);
			exit(1);
		}
	}
}

willoption(option)
	int option;
{
	char *fmt;

	switch (option) {

	case TELOPT_BINARY:
		mode(RAW, 0);
		goto common;

	case TELOPT_ECHO:
		mode(0, ECHO|CRMOD);
		/*FALL THRU*/

	case TELOPT_SGA:
	common:
		hisopts[option] = 1;
		fmt = doopt;
		break;

	case TELOPT_TM:
		fmt = dont;
		break;

	default:
		fmt = dont;
		break;
	}
	sprintf(nfrontp, fmt, option);
	nfrontp += sizeof (dont) - 2;
}

wontoption(option)
	int option;
{
	char *fmt;

	switch (option) {

	case TELOPT_ECHO:
		mode(ECHO|CRMOD, 0);
		goto common;

	case TELOPT_BINARY:
		mode(0, RAW);
		/*FALL THRU*/

	case TELOPT_SGA:
	common:
		hisopts[option] = 0;
		fmt = dont;
		break;

	default:
		fmt = dont;
	}
	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);
		goto common;

	case TELOPT_BINARY:
		mode(RAW, 0);
		/*FALL THRU*/

	case TELOPT_SGA:
	common:
		fmt = will;
		break;

	default:
		fmt = wont;
		break;
	}
	sprintf(nfrontp, fmt, option);
	nfrontp += sizeof (doopt) - 2;
}

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;
}

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;
}

netflush()
{
	int n;

	if ((n = nfrontp - nbackp) > 0)
		n = write(net, nbackp, n);
	if (n < 0) {
		if (errno == EWOULDBLOCK)
			return;
		/* should blow this guy away... */
		return;
	}
	nbackp += n;
	if (nbackp == nfrontp)
		nbackp = nfrontp = netobuf;
}

cleanup()
{

	rmut();
	vhangup();	/* XXX */
	shutdown(net, 2);
	kill(0, SIGKILL);
	exit(1);
}

#include <utmp.h>

struct	utmp wtmp;
char	wtmpf[]	= "/usr/adm/wtmp";
char	utmp[] = "/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;

	f = open(utmp, 2);
	if (f >= 0) {
		while(read(f, (char *)&wtmp, sizeof (wtmp)) == sizeof (wtmp)) {
			if (SCMPN(wtmp.ut_line, line+5) || wtmp.ut_name[0]==0)
				continue;
			lseek(f, -(long)sizeof (wtmp), 1);
			SCPYN(wtmp.ut_name, "");
			SCPYN(wtmp.ut_host, "");
			time(&wtmp.ut_time);
			write(f, (char *)&wtmp, sizeof (wtmp));
			found++;
		}
		close(f);
	}
	if (found) {
		f = open(wtmpf, 1);
		if (f >= 0) {
			SCPYN(wtmp.ut_line, line+5);
			SCPYN(wtmp.ut_name, "");
			SCPYN(wtmp.ut_host, "");
			time(&wtmp.ut_time);
			lseek(f, (long)0, 2);
			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);
}

/*
 * Convert network-format internet address
 * to base 256 d.d.d.d representation.
 */
char *
ntoa(in)
	struct in_addr in;
{
	static char b[18];
	register char *p;

	p = (char *)&in;
#define	UC(b)	(((int)b)&0xff)
	sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3]));
	return (b);
}
Commit	Line	Data
ac6e6727	1	#ifndef lint
0c285f22	2	static char sccsid[] = "@(#)telnetd.c 4.21 83/05/24";
ac6e6727 BJ	3	#endif
ac6e6727 BJ	4
66b878f6 BJ	5	/*
	6	* Stripped-down telnet server.
	7	*/
de3b21e8 SL	8	#include <sys/types.h>
	9	#include <sys/socket.h>
	10
	11	#include <netinet/in.h>
	12
2b597a6b SL	13	#include <arpa/telnet.h>
2b597a6b SL	14
66b878f6 BJ	15	#include <stdio.h>
	16	#include <signal.h>
	17	#include <errno.h>
	18	#include <sgtty.h>
	19	#include <wait.h>
9f005877	20	#include <netdb.h>
0c285f22	21	#include <getty.h>
de3b21e8	22
66b878f6	23	#define BELL '\07'
66b878f6 BJ	24
	25	char hisopts[256];
	26	char myopts[256];
	27
	28	char doopt[] = { IAC, DO, '%', 'c', 0 };
	29	char dont[] = { IAC, DONT, '%', 'c', 0 };
	30	char will[] = { IAC, WILL, '%', 'c', 0 };
	31	char wont[] = { IAC, WONT, '%', 'c', 0 };
	32
	33	/*
	34	* I/O data buffers, pointers, and counters.
	35	*/
	36	char ptyibuf[BUFSIZ], *ptyip = ptyibuf;
	37	char ptyobuf[BUFSIZ], pfrontp = ptyobuf, pbackp = ptyobuf;
	38	char netibuf[BUFSIZ], *netip = netibuf;
9ef3087d	39	char netobuf[BUFSIZ], nfrontp = netobuf, nbackp = netobuf;
66b878f6 BJ	40	int pcc, ncc;
	41
	42	int pty, net;
	43	int inter;
f553aca8	44	int reapchild();
66b878f6 BJ	45	extern int errno;
	46	char line[] = "/dev/ptyp0";
	47
9f005877	48	struct sockaddr_in sin = { AF_INET };
66b878f6 BJ	49
	50	main(argc, argv)
	51	char *argv[];
	52	{
f553aca8	53	int s, pid, options;
9f005877	54	struct servent *sp;
66b878f6	55
9f005877 SL	56	sp = getservbyname("telnet", "tcp");
	57	if (sp == 0) {
	58	fprintf(stderr, "telnetd: tcp/telnet: unknown service\n");
	59	exit(1);
	60	}
	61	sin.sin_port = sp->s_port;
66b878f6	62	argc--, argv++;
f553aca8 SL	63	if (argc > 0 && !strcmp(*argv, "-d")) {
	64	options \|= SO_DEBUG;
	65	argc--, argv++;
	66	}
9f005877 SL	67	if (argc > 0) {
	68	sin.sin_port = atoi(*argv);
	69	if (sin.sin_port <= 0) {
	70	fprintf(stderr, "telnetd: %s: bad port #\n", *argv);
	71	exit(1);
	72	}
5eba30a3	73	sin.sin_port = htons((u_short)sin.sin_port);
9f005877	74	}
16f092bf SL	75	#ifndef DEBUG
	76	if (fork())
	77	exit(0);
	78	for (s = 0; s < 10; s++)
	79	(void) close(s);
	80	(void) open("/", 0);
	81	(void) dup2(0, 1);
	82	(void) dup2(0, 2);
	83	{ int tt = open("/dev/tty", 2);
	84	if (tt > 0) {
	85	ioctl(tt, TIOCNOTTY, 0);
	86	close(tt);
	87	}
	88	}
	89	#endif
de3b21e8	90	again:
9de2cbb6	91	s = socket(AF_INET, SOCK_STREAM, 0, 0);
de3b21e8 SL	92	if (s < 0) {
	93	perror("telnetd: socket");;
	94	sleep(5);
	95	goto again;
	96	}
f553aca8 SL	97	if (options & SO_DEBUG)
	98	if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
	99	perror("telnetd: setsockopt (SO_DEBUG)");
f553aca8 SL	100	if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
f553aca8 SL	101	perror("telnetd: setsockopt (SO_KEEPALIVE)");
de3b21e8 SL	102	while (bind(s, (caddr_t)&sin, sizeof (sin), 0) < 0) {
	103	perror("telnetd: bind");
	104	sleep(5);
	105	}
349e2d84	106	sigset(SIGCHLD, reapchild);
de3b21e8	107	listen(s, 10);
66b878f6	108	for (;;) {
37c640e2 SL	109	struct sockaddr_in from;
37c640e2 SL	110	int s2, fromlen = sizeof (from);
de3b21e8	111
37c640e2	112	s2 = accept(s, (caddr_t)&from, &fromlen);
de3b21e8	113	if (s2 < 0) {
f553aca8 SL	114	if (errno == EINTR)
f553aca8 SL	115	continue;
8f2758db	116	perror("telnetd: accept");
66b878f6 BJ	117	sleep(1);
	118	continue;
	119	}
	120	if ((pid = fork()) < 0)
	121	printf("Out of processes\n");
d05f347d SL	122	else if (pid == 0) {
d05f347d SL	123	signal(SIGCHLD, SIG_IGN);
37c640e2	124	doit(s2, &from);
d05f347d	125	}
de3b21e8	126	close(s2);
66b878f6 BJ	127	}
	128	/NOTREACHED/
	129	}
	130
f553aca8 SL	131	reapchild()
	132	{
	133	union wait status;
	134
	135	while (wait3(&status, WNOHANG, 0) > 0)
	136	;
	137	}
	138
66b878f6 BJ	139	int cleanup();
	140
	141	/*
	142	* Get a pty, scan input lines.
	143	*/
37c640e2 SL	144	doit(f, who)
	145	int f;
	146	struct sockaddr_in *who;
66b878f6	147	{
37c640e2	148	char cp = line, host, *ntoa();
66b878f6 BJ	149	int i, p, cc, t;
66b878f6 BJ	150	struct sgttyb b;
37c640e2	151	struct hostent *hp;
66b878f6 BJ	152
	153	for (i = 0; i < 16; i++) {
	154	cp[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
	155	p = open(cp, 2);
	156	if (p > 0)
	157	goto gotpty;
	158	}
8f2758db SL	159	fatal(f, "All network ports in use");
8f2758db SL	160	/NOTREACHED/
66b878f6 BJ	161	gotpty:
	162	dup2(f, 0);
	163	cp[strlen("/dev/")] = 't';
	164	t = open("/dev/tty", 2);
	165	if (t >= 0) {
	166	ioctl(t, TIOCNOTTY, 0);
	167	close(t);
	168	}
	169	t = open(cp, 2);
8f2758db SL	170	if (t < 0)
8f2758db SL	171	fatalperror(f, cp, errno);
66b878f6	172	ioctl(t, TIOCGETP, &b);
9ef3087d	173	b.sg_flags = CRMOD\|XTABS\|ANYP;
66b878f6	174	ioctl(t, TIOCSETP, &b);
9ef3087d	175	ioctl(p, TIOCGETP, &b);
da96b661	176	b.sg_flags &= ~ECHO;
9ef3087d	177	ioctl(p, TIOCSETP, &b);
37c640e2 SL	178	hp = gethostbyaddr(&who->sin_addr, sizeof (struct in_addr),
	179	who->sin_family);
	180	if (hp)
	181	host = hp->h_name;
	182	else
	183	host = ntoa(who->sin_addr);
8f2758db SL	184	if ((i = fork()) < 0)
8f2758db SL	185	fatalperror(f, "fork", errno);
66b878f6 BJ	186	if (i)
	187	telnet(f, p);
	188	close(f);
	189	close(p);
	190	dup2(t, 0);
	191	dup2(t, 1);
	192	dup2(t, 2);
	193	close(t);
0c285f22	194	execl("/bin/login", "login", "-h", host, 0);
8f2758db SL	195	fatalperror(f, "/bin/login", errno);
	196	/NOTREACHED/
	197	}
	198
	199	fatal(f, msg)
	200	int f;
	201	char *msg;
	202	{
	203	char buf[BUFSIZ];
	204
	205	(void) sprintf(buf, "telnetd: %s.\n", msg);
	206	(void) write(f, buf, strlen(buf));
66b878f6 BJ	207	exit(1);
	208	}
	209
8f2758db SL	210	fatalperror(f, msg, errno)
	211	int f;
	212	char *msg;
	213	int errno;
	214	{
	215	char buf[BUFSIZ];
	216	extern char *sys_errlist[];
	217
	218	(void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]);
	219	fatal(f, buf);
	220	}
	221
66b878f6 BJ	222	/*
	223	* Main loop. Select from pty and network, and
	224	* hand data to telnet receiver finite state machine.
	225	*/
	226	telnet(f, p)
	227	{
	228	int on = 1;
0c285f22	229	char hostname[32];
66b878f6 BJ	230
	231	net = f, pty = p;
	232	ioctl(f, FIONBIO, &on);
	233	ioctl(p, FIONBIO, &on);
	234	signal(SIGTSTP, SIG_IGN);
	235	sigset(SIGCHLD, cleanup);
	236
da96b661 SL	237	/*
	238	* Request to do remote echo.
	239	*/
	240	dooption(TELOPT_ECHO);
	241	myopts[TELOPT_ECHO] = 1;
0c285f22 SL	242	/*
	243	* Show banner that getty never gave.
	244	*/
	245	gethostname(hostname, sizeof (hostname));
	246	sprintf(nfrontp, BANNER, hostname, "");
	247	nfrontp += strlen(nfrontp);
66b878f6 BJ	248	for (;;) {
	249	int ibits = 0, obits = 0;
	250	register int c;
	251
	252	/*
	253	* Never look for input if there's still
	254	* stuff in the corresponding output buffer
	255	*/
	256	if (nfrontp - nbackp)
	257	obits \|= (1 << f);
	258	else
	259	ibits \|= (1 << p);
	260	if (pfrontp - pbackp)
	261	obits \|= (1 << p);
	262	else
	263	ibits \|= (1 << f);
	264	if (ncc < 0 && pcc < 0)
	265	break;
de3b21e8	266	select(16, &ibits, &obits, 0, 0);
66b878f6 BJ	267	if (ibits == 0 && obits == 0) {
	268	sleep(5);
	269	continue;
	270	}
	271
	272	/*
	273	* Something to read from the network...
	274	*/
	275	if (ibits & (1 << f)) {
	276	ncc = read(f, netibuf, BUFSIZ);
	277	if (ncc < 0 && errno == EWOULDBLOCK)
	278	ncc = 0;
	279	else {
	280	if (ncc <= 0)
	281	break;
	282	netip = netibuf;
	283	}
	284	}
	285
	286	/*
	287	* Something to read from the pty...
	288	*/
	289	if (ibits & (1 << p)) {
	290	pcc = read(p, ptyibuf, BUFSIZ);
	291	if (pcc < 0 && errno == EWOULDBLOCK)
	292	pcc = 0;
	293	else {
	294	if (pcc <= 0)
	295	break;
	296	ptyip = ptyibuf;
	297	}
	298	}
	299
	300	while (pcc > 0) {
	301	if ((&netobuf[BUFSIZ] - nfrontp) < 2)
	302	break;
	303	c = *ptyip++ & 0377, pcc--;
	304	if (c == IAC)
	305	*nfrontp++ = c;
	306	*nfrontp++ = c;
	307	}
	308	if ((obits & (1 << f)) && (nfrontp - nbackp) > 0)
	309	netflush();
	310	if (ncc > 0)
	311	telrcv();
	312	if ((obits & (1 << p)) && (pfrontp - pbackp) > 0)
	313	ptyflush();
	314	}
	315	cleanup();
	316	}
	317
	318	/*
	319	* State for recv fsm
	320	*/
	321	#define TS_DATA 0 /* base state */
	322	#define TS_IAC 1 /* look for double IAC's */
	323	#define TS_CR 2 /* CR-LF ->'s CR */
	324	#define TS_BEGINNEG 3 /* throw away begin's... */
	325	#define TS_ENDNEG 4 /* ...end's (suboption negotiation) */
	326	#define TS_WILL 5 /* will option negotiation */
	327	#define TS_WONT 6 /* wont " */
	328	#define TS_DO 7 /* do " */
	329	#define TS_DONT 8 /* dont " */
	330
331	telrcv()
332	{
333	register int c;
334	static int state = TS_DATA;
335	struct sgttyb b;
336
337	while (ncc > 0) {
338	if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
339	return;
340	c = *netip++ & 0377, ncc--;
341	switch (state) {
342
343	case TS_DATA:
344	if (c == IAC) {
345	state = TS_IAC;
346	break;
347	}
348	if (inter > 0)
349	break;
350	*pfrontp++ = c;
351	if (!myopts[TELOPT_BINARY] && c == '\r')
352	state = TS_CR;
353	break;
354
355	case TS_CR:
356	if (c && c != '\n')
357	*pfrontp++ = c;
358	state = TS_DATA;
359	break;
360
361	case TS_IAC:
362	switch (c) {
363
364	/*
365	* Send the process on the pty side an
366	* interrupt. Do this with a NULL or
367	* interrupt char; depending on the tty mode.
368	*/
369	case BREAK:
370	case IP:
371	interrupt();
372	break;
373
374	/*
375	* Are You There?
376	*/
377	case AYT:
378	*pfrontp++ = BELL;
379	break;
380
381	/*
382	* Erase Character and
383	* Erase Line
384	*/
385	case EC:
386	case EL:
387	ptyflush(); /* half-hearted */
388	ioctl(pty, TIOCGETP, &b);
389	*pfrontp++ = (c == EC) ?
390	b.sg_erase : b.sg_kill;
391	break;
392
393	/*
394	* Check for urgent data...
395	*/
396	case DM:
397	break;
398
399	/*
400	* Begin option subnegotiation...
401	*/
402	case SB:
403	state = TS_BEGINNEG;
404	continue;
405
406	case WILL:
407	case WONT:
408	case DO:
409	case DONT:
410	state = TS_WILL + (c - WILL);
411	continue;
412
413	case IAC:
414	*pfrontp++ = c;
415	break;
416	}
417	state = TS_DATA;
418	break;
419
420	case TS_BEGINNEG:
421	if (c == IAC)
422	state = TS_ENDNEG;
423	break;
424
425	case TS_ENDNEG:
426	state = c == SE ? TS_DATA : TS_BEGINNEG;
427	break;
428
429	case TS_WILL:
430	if (!hisopts[c])
431	willoption(c);
432	state = TS_DATA;
433	continue;
434
435	case TS_WONT:
436	if (hisopts[c])
437	wontoption(c);
438	state = TS_DATA;
439	continue;
440
441	case TS_DO:
442	if (!myopts[c])
443	dooption(c);
444	state = TS_DATA;
445	continue;
446
447	case TS_DONT:
448	if (myopts[c]) {
449	myopts[c] = 0;
450	sprintf(nfrontp, wont, c);
da96b661	451	nfrontp += sizeof (wont) - 2;
66b878f6 BJ	452	}
	453	state = TS_DATA;
	454	continue;
	455
	456	default:
de3b21e8	457	printf("telnetd: panic state=%d\n", state);
66b878f6 BJ	458	exit(1);
	459	}
	460	}
	461	}
	462
	463	willoption(option)
	464	int option;
	465	{
	466	char *fmt;
	467
	468	switch (option) {
	469
	470	case TELOPT_BINARY:
	471	mode(RAW, 0);
	472	goto common;
	473
	474	case TELOPT_ECHO:
	475	mode(0, ECHO\|CRMOD);
	476	/FALL THRU/
	477
	478	case TELOPT_SGA:
	479	common:
	480	hisopts[option] = 1;
	481	fmt = doopt;
	482	break;
	483
	484	case TELOPT_TM:
	485	fmt = dont;
	486	break;
	487
	488	default:
	489	fmt = dont;
	490	break;
	491	}
13646f15	492	sprintf(nfrontp, fmt, option);
da96b661	493	nfrontp += sizeof (dont) - 2;
66b878f6 BJ	494	}
	495
	496	wontoption(option)
	497	int option;
	498	{
	499	char *fmt;
	500
	501	switch (option) {
	502
	503	case TELOPT_ECHO:
	504	mode(ECHO\|CRMOD, 0);
	505	goto common;
	506
	507	case TELOPT_BINARY:
	508	mode(0, RAW);
	509	/FALL THRU/
	510
	511	case TELOPT_SGA:
	512	common:
	513	hisopts[option] = 0;
	514	fmt = dont;
	515	break;
	516
	517	default:
	518	fmt = dont;
	519	}
	520	sprintf(nfrontp, fmt, option);
da96b661	521	nfrontp += sizeof (doopt) - 2;
66b878f6 BJ	522	}
	523
	524	dooption(option)
	525	int option;
	526	{
	527	char *fmt;
	528
	529	switch (option) {
	530
	531	case TELOPT_TM:
	532	fmt = wont;
	533	break;
	534
	535	case TELOPT_ECHO:
	536	mode(ECHO\|CRMOD, 0);
	537	goto common;
	538
	539	case TELOPT_BINARY:
	540	mode(RAW, 0);
	541	/FALL THRU/
	542
	543	case TELOPT_SGA:
	544	common:
	545	fmt = will;
	546	break;
	547
	548	default:
	549	fmt = wont;
	550	break;
	551	}
	552	sprintf(nfrontp, fmt, option);
da96b661	553	nfrontp += sizeof (doopt) - 2;
66b878f6 BJ	554	}
	555
	556	mode(on, off)
	557	int on, off;
	558	{
	559	struct sgttyb b;
	560
	561	ptyflush();
	562	ioctl(pty, TIOCGETP, &b);
	563	b.sg_flags \|= on;
	564	b.sg_flags &= ~off;
	565	ioctl(pty, TIOCSETP, &b);
	566	}
	567
	568	/*
	569	* Send interrupt to process on other side of pty.
	570	* If it is in raw mode, just write NULL;
	571	* otherwise, write intr char.
	572	*/
	573	interrupt()
	574	{
	575	struct sgttyb b;
	576	struct tchars tchars;
	577
	578	ptyflush(); /* half-hearted */
	579	ioctl(pty, TIOCGETP, &b);
	580	if (b.sg_flags & RAW) {
	581	*pfrontp++ = '\0';
	582	return;
	583	}
	584	*pfrontp++ = ioctl(pty, TIOCGETC, &tchars) < 0 ?
	585	'\177' : tchars.t_intrc;
	586	}
	587
	588	ptyflush()
	589	{
	590	int n;
	591
	592	if ((n = pfrontp - pbackp) > 0)
	593	n = write(pty, pbackp, n);
9f005877 SL	594	if (n < 0)
9f005877 SL	595	return;
66b878f6 BJ	596	pbackp += n;
	597	if (pbackp == pfrontp)
	598	pbackp = pfrontp = ptyobuf;
	599	}
	600
	601	netflush()
	602	{
	603	int n;
	604
	605	if ((n = nfrontp - nbackp) > 0)
	606	n = write(net, nbackp, n);
9f005877 SL	607	if (n < 0) {
	608	if (errno == EWOULDBLOCK)
	609	return;
	610	/* should blow this guy away... */
	611	return;
	612	}
66b878f6 BJ	613	nbackp += n;
	614	if (nbackp == nfrontp)
	615	nbackp = nfrontp = netobuf;
	616	}
	617
	618	cleanup()
	619	{
66b878f6 BJ	620
66b878f6 BJ	621	rmut();
a7f6263e	622	vhangup(); /* XXX */
ff24c640	623	shutdown(net, 2);
66b878f6 BJ	624	kill(0, SIGKILL);
	625	exit(1);
	626	}
	627
	628	#include <utmp.h>
	629
	630	struct utmp wtmp;
	631	char wtmpf[] = "/usr/adm/wtmp";
	632	char utmp[] = "/etc/utmp";
da96b661 SL	633	#define SCPYN(a, b) strncpy(a, b, sizeof (a))
da96b661 SL	634	#define SCMPN(a, b) strncmp(a, b, sizeof (a))
66b878f6 BJ	635
	636	rmut()
	637	{
	638	register f;
	639	int found = 0;
	640
	641	f = open(utmp, 2);
	642	if (f >= 0) {
da96b661	643	while(read(f, (char *)&wtmp, sizeof (wtmp)) == sizeof (wtmp)) {
66b878f6 BJ	644	if (SCMPN(wtmp.ut_line, line+5) \|\| wtmp.ut_name[0]==0)
66b878f6 BJ	645	continue;
da96b661	646	lseek(f, -(long)sizeof (wtmp), 1);
66b878f6	647	SCPYN(wtmp.ut_name, "");
37c640e2	648	SCPYN(wtmp.ut_host, "");
66b878f6	649	time(&wtmp.ut_time);
da96b661	650	write(f, (char *)&wtmp, sizeof (wtmp));
66b878f6 BJ	651	found++;
	652	}
	653	close(f);
	654	}
	655	if (found) {
	656	f = open(wtmpf, 1);
	657	if (f >= 0) {
	658	SCPYN(wtmp.ut_line, line+5);
	659	SCPYN(wtmp.ut_name, "");
37c640e2	660	SCPYN(wtmp.ut_host, "");
66b878f6 BJ	661	time(&wtmp.ut_time);
66b878f6 BJ	662	lseek(f, (long)0, 2);
da96b661	663	write(f, (char *)&wtmp, sizeof (wtmp));
66b878f6 BJ	664	close(f);
	665	}
	666	}
	667	chmod(line, 0666);
	668	chown(line, 0, 0);
	669	line[strlen("/dev/")] = 'p';
	670	chmod(line, 0666);
	671	chown(line, 0, 0);
	672	}
37c640e2 SL	673
	674	/*
	675	* Convert network-format internet address
	676	* to base 256 d.d.d.d representation.
	677	*/
	678	char *
	679	ntoa(in)
	680	struct in_addr in;
	681	{
	682	static char b[18];
	683	register char *p;
	684
	685	p = (char *)&in;
	686	#define UC(b) (((int)b)&0xff)
	687	sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3]));
	688	return (b);
	689	}