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

/*
 * Copyright (c) 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)utility.c	5.2 (Berkeley) %G%";
#endif /* not lint */


#include "telnetd.h"

/*
 * utility functions performing io related tasks
 */

/*
 * 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()
{
    void netflush();

    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();
    }
}  /* end of ttloop */

/*
 * 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");
    }
    if (FD_ISSET(s, &excepts)) {
	return 1;
    } else {
	return 0;
    }
}

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;
    }
}  /* end of nextitem */


/*
 * 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;
}  /* end of netclear */

/*
 *  netflush
 *		Send as much data as possible to the network,
 *	handling requests for urgent data.
 */
void
netflush()
{
    int n;
    extern int not42;

    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 || errno == EINTR)
		return;
	cleanup();
    }
    nbackp += n;
    if (nbackp >= neturg) {
	neturg = 0;
    }
    if (nbackp == nfrontp) {
	nbackp = nfrontp = netobuf;
    }
    return;
}  /* end of netflush */


/*
 * writenet
 *
 * Just a handy little function to write a bit of raw data to the net.
 * It will force a transmit of the buffer if necessary
 *
 * arguments
 *    ptr - A pointer to a character string to write
 *    len - How many bytes to write
 */
writenet(ptr, len)
register char *ptr;
register int len;
{
	/* flush buffer if no room for new data) */
	if ((&netobuf[BUFSIZ] - nfrontp) < len) {
		/* if this fails, don't worry, buffer is a little big */
		netflush();
	}

	bcopy(ptr, nfrontp, len);
	nfrontp += len;

}  /* end of writenet */


/*
 * miscellaneous functions doing a variety of little jobs follow ...
 */


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

	(void) sprintf(buf, "telnetd: %s.\r\n", msg);
	(void) write(f, buf, (int)strlen(buf));
	sleep(1);	/*XXX*/
	exit(1);
}

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

	(void) sprintf(buf, "%s: %s\r\n", msg, strerror(errno));
	fatal(f, buf);
}

char editedhost[32];

edithost(pat, host)
	register char *pat;
	register char *host;
{
	register char *res = editedhost;
	char *strncpy();

	if (!pat)
		pat = "";
	while (*pat) {
		switch (*pat) {

		case '#':
			if (*host)
				host++;
			break;

		case '@':
			if (*host)
				*res++ = *host++;
			break;

		default:
			*res++ = *pat;
			break;
		}
		if (res == &editedhost[sizeof editedhost - 1]) {
			*res = '\0';
			return;
		}
		pat++;
	}
	if (*host)
		(void) strncpy(res, host,
				sizeof editedhost - (res - editedhost) -1);
	else
		*res = '\0';
	editedhost[sizeof editedhost - 1] = '\0';
}

static char *putlocation;

putstr(s)
register char *s;
{

	while (*s)
		putchr(*s++);
}

putchr(cc)
{
	*putlocation++ = cc;
}

putf(cp, where)
register char *cp;
char *where;
{
	char *slash;
#ifndef	NO_GETTYTAB
	char datebuffer[60];
#endif	/* NO_GETTYTAB */
	extern char *rindex();

	putlocation = where;

	while (*cp) {
		if (*cp != '%') {
			putchr(*cp++);
			continue;
		}
		switch (*++cp) {

		case 't':
			slash = rindex(line, '/');
			if (slash == (char *) 0)
				putstr(line);
			else
				putstr(&slash[1]);
			break;

		case 'h':
			putstr(editedhost);
			break;

#ifndef	NO_GETTYTAB
		case 'd':
			get_date(datebuffer);
			putstr(datebuffer);
			break;
#endif	/* NO_GETTYTAB */

		case '%':
			putchr('%');
			break;
		}
		cp++;
	}
}

/*ARGSUSED*/
#ifdef	NO_GETTYTAB
getent(cp, name)
char *cp, *name;
{
	return(0);
}

/*ARGSUSED*/
char *
getstr(cp, cpp)
char *cp, **cpp;
{
	return(0);
}
#endif	/* NO_GETTYTAB */
Commit	Line	Data
ea139302 PB	1	/*
	2	* Copyright (c) 1989 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms are permitted
	6	* provided that the above copyright notice and this paragraph are
	7	* duplicated in all such forms and that any documentation,
	8	* advertising materials, and other materials related to such
	9	* distribution and use acknowledge that the software was developed
	10	* by the University of California, Berkeley. The name of the
	11	* University may not be used to endorse or promote products derived
	12	* from this software without specific prior written permission.
	13	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	15	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	16	*/
	17
	18	#ifndef lint
396aa79f	19	static char sccsid[] = "@(#)utility.c 5.2 (Berkeley) %G%";
ea139302 PB	20	#endif /* not lint */
	21
	22
	23	#include "telnetd.h"
	24
	25	/*
	26	* utility functions performing io related tasks
	27	*/
	28
	29	/*
	30	* ttloop
	31	*
	32	* A small subroutine to flush the network output buffer, get some data
	33	* from the network, and pass it through the telnet state machine. We
	34	* also flush the pty input buffer (by dropping its data) if it becomes
	35	* too full.
	36	*/
	37
	38	void
	39	ttloop()
	40	{
	41	void netflush();
	42
	43	if (nfrontp-nbackp) {
	44	netflush();
	45	}
	46	ncc = read(net, netibuf, sizeof netibuf);
	47	if (ncc < 0) {
	48	syslog(LOG_INFO, "ttloop: read: %m\n");
	49	exit(1);
	50	} else if (ncc == 0) {
	51	syslog(LOG_INFO, "ttloop: peer died: %m\n");
	52	exit(1);
	53	}
	54	netip = netibuf;
	55	telrcv(); /* state machine */
	56	if (ncc > 0) {
	57	pfrontp = pbackp = ptyobuf;
	58	telrcv();
	59	}
	60	} /* end of ttloop */
	61
	62	/*
	63	* Check a descriptor to see if out of band data exists on it.
	64	*/
	65	stilloob(s)
	66	int s; /* socket number */
	67	{
	68	static struct timeval timeout = { 0 };
	69	fd_set excepts;
	70	int value;
	71
	72	do {
	73	FD_ZERO(&excepts);
	74	FD_SET(s, &excepts);
	75	value = select(s+1, (fd_set )0, (fd_set )0, &excepts, &timeout);
	76	} while ((value == -1) && (errno == EINTR));
	77
	78	if (value < 0) {
	79	fatalperror(pty, "select");
	80	}
	81	if (FD_ISSET(s, &excepts)) {
	82	return 1;
	83	} else {
84	return 0;
85	}
86	}
87
88	ptyflush()
89	{
90	int n;
91
92	if ((n = pfrontp - pbackp) > 0)
93	n = write(pty, pbackp, n);
94	if (n < 0)
95	return;
96	pbackp += n;
97	if (pbackp == pfrontp)
98	pbackp = pfrontp = ptyobuf;
99	}
100
101	/*
102	* nextitem()
103	*
104	* Return the address of the next "item" in the TELNET data
105	* stream. This will be the address of the next character if
106	* the current address is a user data character, or it will
107	* be the address of the character following the TELNET command
108	* if the current address is a TELNET IAC ("I Am a Command")
109	* character.
110	*/
111	char *
112	nextitem(current)
113	char *current;
114	{
115	if ((*current&0xff) != IAC) {
116	return current+1;
117	}
118	switch (*(current+1)&0xff) {
119	case DO:
120	case DONT:
121	case WILL:
122	case WONT:
123	return current+3;
124	case SB: /* loop forever looking for the SE */
125	{
126	register char *look = current+2;
127
128	for (;;) {
129	if ((*look++&0xff) == IAC) {
130	if ((*look++&0xff) == SE) {
131	return look;
132	}
133	}
134	}
135	}
136	default:
137	return current+2;
138	}
139	} /* end of nextitem */
140
141
142	/*
143	* netclear()
144	*
145	* We are about to do a TELNET SYNCH operation. Clear
146	* the path to the network.
147	*
148	* Things are a bit tricky since we may have sent the first
149	* byte or so of a previous TELNET command into the network.
150	* So, we have to scan the network buffer from the beginning
151	* until we are up to where we want to be.
152	*
153	* A side effect of what we do, just to keep things
154	* simple, is to clear the urgent data pointer. The principal
155	* caller should be setting the urgent data pointer AFTER calling
156	* us in any case.
157	*/
158	netclear()
159	{
160	register char thisitem, next;
161	char *good;
162	#define wewant(p) ((nfrontp > p) && ((*p&0xff) == IAC) && \
163	(((p+1)&0xff) != EC) && (((p+1)&0xff) != EL))
164
165	thisitem = netobuf;
166
167	while ((next = nextitem(thisitem)) <= nbackp) {
168	thisitem = next;
169	}
170
171	/* Now, thisitem is first before/at boundary. */
172
173	good = netobuf; /* where the good bytes go */
174
175	while (nfrontp > thisitem) {
176	if (wewant(thisitem)) {
177	int length;
178
179	next = thisitem;
180	do {
181	next = nextitem(next);
182	} while (wewant(next) && (nfrontp > next));
183	length = next-thisitem;
184	bcopy(thisitem, good, length);
185	good += length;
186	thisitem = next;
187	} else {
188	thisitem = nextitem(thisitem);
189	}
190	}
191
192	nbackp = netobuf;
193	nfrontp = good; /* next byte to be sent */
194	neturg = 0;
195	} /* end of netclear */
196
197	/*
198	* netflush
199	* Send as much data as possible to the network,
200	* handling requests for urgent data.
201	*/
202	void
203	netflush()
204	{
205	int n;
206	extern int not42;
207
208	if ((n = nfrontp - nbackp) > 0) {
209	/*
210	* if no urgent data, or if the other side appears to be an
211	* old 4.2 client (and thus unable to survive TCP urgent data),
212	* write the entire buffer in non-OOB mode.
213	*/
214	if ((neturg == 0) \|\| (not42 == 0)) {
215	n = write(net, nbackp, n); /* normal write */
216	} else {
217	n = neturg - nbackp;
218	/*
219	* In 4.2 (and 4.3) systems, there is some question about
220	* what byte in a sendOOB operation is the "OOB" data.
221	* To make ourselves compatible, we only send ONE byte
222	* out of band, the one WE THINK should be OOB (though
223	* we really have more the TCP philosophy of urgent data
224	* rather than the Unix philosophy of OOB data).
225	*/
226	if (n > 1) {
227	n = send(net, nbackp, n-1, 0); /* send URGENT all by itself */
228	} else {
229	n = send(net, nbackp, n, MSG_OOB); /* URGENT data */
230	}
231	}
232	}
233	if (n < 0) {
234	if (errno == EWOULDBLOCK \|\| errno == EINTR)
235	return;
236	cleanup();
237	}
238	nbackp += n;
239	if (nbackp >= neturg) {
240	neturg = 0;
241	}
242	if (nbackp == nfrontp) {
243	nbackp = nfrontp = netobuf;
244	}
245	return;
246	} /* end of netflush */
247
248
249	/*
250	* writenet
251	*
252	* Just a handy little function to write a bit of raw data to the net.
253	* It will force a transmit of the buffer if necessary
254	*
255	* arguments
256	* ptr - A pointer to a character string to write
257	* len - How many bytes to write
258	*/
259	writenet(ptr, len)
260	register char *ptr;
261	register int len;
262	{
263	/* flush buffer if no room for new data) */
264	if ((&netobuf[BUFSIZ] - nfrontp) < len) {
265	/* if this fails, don't worry, buffer is a little big */
266	netflush();
267	}
268
269	bcopy(ptr, nfrontp, len);
270	nfrontp += len;
271
272	} /* end of writenet */
273
274
275	/*
276	* miscellaneous functions doing a variety of little jobs follow ...
277	*/
278
279
280	fatal(f, msg)
281	int f;
282	char *msg;
283	{
284	char buf[BUFSIZ];
285
286	(void) sprintf(buf, "telnetd: %s.\r\n", msg);
287	(void) write(f, buf, (int)strlen(buf));
288	sleep(1); /XXX/
289	exit(1);
290	}
291
292	fatalperror(f, msg)
293	int f;
294	char *msg;
295	{
396aa79f	296	char buf[BUFSIZ], *strerror();
ea139302	297
396aa79f	298	(void) sprintf(buf, "%s: %s\r\n", msg, strerror(errno));
ea139302 PB	299	fatal(f, buf);
	300	}
	301
	302	char editedhost[32];
	303
	304	edithost(pat, host)
	305	register char *pat;
	306	register char *host;
	307	{
	308	register char *res = editedhost;
	309	char *strncpy();
	310
	311	if (!pat)
	312	pat = "";
	313	while (*pat) {
	314	switch (*pat) {
	315
	316	case '#':
	317	if (*host)
	318	host++;
	319	break;
	320
	321	case '@':
	322	if (*host)
	323	res++ = host++;
	324	break;
	325
	326	default:
	327	res++ = pat;
	328	break;
	329	}
	330	if (res == &editedhost[sizeof editedhost - 1]) {
	331	*res = '\0';
	332	return;
	333	}
	334	pat++;
	335	}
	336	if (*host)
	337	(void) strncpy(res, host,
	338	sizeof editedhost - (res - editedhost) -1);
	339	else
	340	*res = '\0';
	341	editedhost[sizeof editedhost - 1] = '\0';
	342	}
	343
	344	static char *putlocation;
	345
	346	putstr(s)
	347	register char *s;
	348	{
	349
	350	while (*s)
	351	putchr(*s++);
	352	}
	353
	354	putchr(cc)
	355	{
	356	*putlocation++ = cc;
	357	}
	358
	359	putf(cp, where)
	360	register char *cp;
	361	char *where;
	362	{
363	char *slash;
364	#ifndef NO_GETTYTAB
365	char datebuffer[60];
366	#endif /* NO_GETTYTAB */
367	extern char *rindex();
368
369	putlocation = where;
370
371	while (*cp) {
372	if (*cp != '%') {
373	putchr(*cp++);
374	continue;
375	}
376	switch (*++cp) {
377
378	case 't':
379	slash = rindex(line, '/');
380	if (slash == (char *) 0)
381	putstr(line);
382	else
383	putstr(&slash[1]);
384	break;
385
386	case 'h':
387	putstr(editedhost);
388	break;
389
390	#ifndef NO_GETTYTAB
391	case 'd':
392	get_date(datebuffer);
393	putstr(datebuffer);
394	break;
395	#endif /* NO_GETTYTAB */
396
397	case '%':
398	putchr('%');
399	break;
400	}
401	cp++;
402	}
403	}
404
405	/ARGSUSED/
406	#ifdef NO_GETTYTAB
407	getent(cp, name)
408	char cp, name;
409	{
410	return(0);
411	}
412
413	/ARGSUSED/
414	char *
415	getstr(cp, cpp)
416	char cp, *cpp;
417	{
418	return(0);
419	}
420	#endif /* NO_GETTYTAB */