xref: /dflybsd-src/usr.bin/tip/unidialer.c (revision 44e4a0619b988dddeb18754d7cd2705cf6f7950c)
1 /*
2  * Copyright (c) 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * @(#)unidialer.c	8.1 (Berkeley) 6/6/93
34  * $FreeBSD: src/usr.bin/tip/libacu/unidialer.c,v 1.7 1999/08/28 01:06:30 peter Exp $
35  */
36 
37 /*
38  * Generalized routines for calling up on a Hayes AT command set based modem.
39  * Control variables are pulled out of a modem caps-style database to
40  * configure the driver for a particular modem.
41  */
42 #include "tip.h"
43 #include "pathnames.h"
44 
45 #include <sys/times.h>
46 #include <assert.h>
47 #include <err.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 
51 #include "acucommon.h"
52 #include "tod.h"
53 
54 /* #define DEBUG */
55 #define	MAXRETRY	5
56 
57 typedef enum
58 {
59 	mpt_notype, mpt_string, mpt_number, mpt_boolean
60 } modem_parm_type_t;
61 
62 typedef struct {
63 	modem_parm_type_t modem_parm_type;
64 	const char *name;
65 	union {
66 		char **string;
67 		unsigned int *number;
68 	} value;
69 	union {
70 		char *string;
71 		unsigned int number;
72 	} default_value;
73 } modem_parm_t;
74 
75 /*
76 	Configuration
77 */
78 static char modem_name [80];
79 static char *dial_command;
80 static char *hangup_command;
81 static char *echo_off_command;
82 static char *reset_command;
83 static char *init_string;
84 static char *escape_sequence;
85 static int hw_flow_control;
86 static int lock_baud;
87 static unsigned int intercharacter_delay;
88 static unsigned int intercommand_delay;
89 static unsigned int escape_guard_time;
90 static unsigned int reset_delay;
91 
92 static int unidialer_dialer(char *num, char *acu);
93 static void unidialer_disconnect(void);
94 static void unidialer_abort(void);
95 static int unidialer_connect(void);
96 static int unidialer_swallow(char *);
97 #ifdef DEBUG
98 static void unidialer_verbose_read (void);
99 #endif
100 static void unidialer_modem_cmd(int fd, const char *cmd);
101 static void unidialer_write(int fd, const char *cp, int n);
102 static void unidialer_write_str(int fd, const char *cp);
103 static void sigALRM(int);
104 static int unidialersync(void);
105 
106 static acu_t unidialer =
107 {
108 	modem_name,
109 	unidialer_dialer,
110 	unidialer_disconnect,
111 	unidialer_abort
112 };
113 
114 /*
115 	Table of parameters kept in modem database
116 */
117 modem_parm_t modem_parms [] = {
118 	{ mpt_string, "dial_command", { &dial_command }, { "ATDT%s\r" } },
119 	{ mpt_string, "hangup_command", { &hangup_command }, { "ATH\r", } },
120 	{ mpt_string, "echo_off_command", { &echo_off_command }, { "ATE0\r" } },
121 	{ mpt_string, "reset_command", { &reset_command }, { "ATZ\r" } },
122 	{ mpt_string, "init_string", { &init_string }, { "AT{ &F\r", } },
123 	{ mpt_string, "escape_sequence", { &escape_sequence }, { "+++" } },
124 	{ mpt_boolean, "hw_flow_control", { (char **)&hw_flow_control }, { NULL } },
125 	{ mpt_boolean, "lock_baud", { (char **)&lock_baud }, { NULL } },
126 	{ mpt_number, "intercharacter_delay", { (char **)&intercharacter_delay }, { (char *)50 } },
127 	{ mpt_number, "intercommand_delay", { (char **)&intercommand_delay }, { (char *)300 } },
128 	{ mpt_number, "escape_guard_time", { (char **)&escape_guard_time }, { (char *)300 } },
129 	{ mpt_number, "reset_delay", { (char **)&reset_delay }, { (char *)3000 } },
130 	{ mpt_notype, NULL, { NULL }, { NULL } }
131 };
132 
133 /*
134 	Global vars
135 */
136 static int timeout = 0;
137 static int connected = 0;
138 static jmp_buf timeoutbuf;
139 
140 #define cgetflag(f)	(cgetcap(bp, f, ':') != NULL)
141 
142 #ifdef DEBUG
143 
144 #define print_str(x) printf (#x " = %s\n", x)
145 #define print_num(x) printf (#x " = %d\n", x)
146 
147 void dumpmodemparms (char *modem)
148 {
149 		printf ("modem parms for %s\n", modem);
150 		print_str (dial_command);
151 		print_str (hangup_command);
152 		print_str (echo_off_command);
153 		print_str (reset_command);
154 		print_str (init_string);
155 		print_str (escape_sequence);
156 		print_num (lock_baud);
157 		print_num (intercharacter_delay);
158 		print_num (intercommand_delay);
159 		print_num (escape_guard_time);
160 		print_num (reset_delay);
161 		printf ("\n");
162 }
163 #endif
164 
165 static int getmodemparms (const char *modem)
166 {
167 	char *bp, *db_array [3], *modempath;
168 	int ndx, stat;
169 	modem_parm_t *mpp;
170 
171 	modempath = getenv ("MODEMS");
172 
173 	ndx = 0;
174 
175 	if (modempath != NULL)
176 		db_array [ndx++] = modempath;
177 
178 	db_array [ndx++] = _PATH_MODEMS;
179 	db_array [ndx] = NULL;
180 
181 	if ((stat = cgetent (&bp, db_array, (char *)modem)) < 0) {
182 		switch (stat) {
183 		case -1:
184 			warnx ("unknown modem %s", modem);
185 			break;
186 		case -2:
187 			warnx ("can't open modem description file");
188 			break;
189 		case -3:
190 			warnx ("possible reference loop in modem description file");
191 			break;
192 		}
193 		return 0;
194 	}
195 	for (mpp = modem_parms; mpp->name; mpp++)
196 	{
197 		switch (mpp->modem_parm_type)
198 		{
199 		case mpt_string:
200 			if (cgetstr (bp, (char *)mpp->name, mpp->value.string) == -1)
201 				*mpp->value.string = mpp->default_value.string;
202 			break;
203 		case mpt_number:
204 		{
205 			long l;
206 			if (cgetnum (bp, (char *)mpp->name, &l) == -1)
207 				*mpp->value.number = mpp->default_value.number;
208 			else
209 				*mpp->value.number = (unsigned int)l;
210 		}
211 			break;
212 		case mpt_boolean:
213 			*mpp->value.number = cgetflag ((char *)mpp->name);
214 			break;
215 		default:
216 			break;
217 		}
218 	}
219 	strncpy (modem_name, modem, sizeof (modem_name) - 1);
220 	modem_name [sizeof (modem_name) - 1] = '\0';
221 	return 1;
222 }
223 
224 /*
225 */
226 acu_t *
227 unidialer_getmodem(const char *modem_name)
228 {
229 	acu_t* rc = NULL;
230 	if (getmodemparms (modem_name))
231 		rc = &unidialer;
232 	return rc;
233 }
234 
235 static int
236 unidialer_modem_ready(void)
237 {
238 	int state;
239 	ioctl (FD, TIOCMGET, &state);
240 	return (state & TIOCM_DSR) ? 1 : 0;
241 }
242 
243 static int unidialer_waitfor_modem_ready (int ms)
244 {
245 	int count;
246 	for (count = 0; count < ms; count += 100)
247 	{
248 		if (unidialer_modem_ready ())
249 		{
250 #ifdef DEBUG
251 			printf ("unidialer_waitfor_modem_ready: modem ready.\n");
252 #endif
253 			break;
254 		}
255 		acu_nap (100);
256 	}
257 	return (count < ms);
258 }
259 
260 static void
261 unidialer_tty_clocal(int flag)
262 {
263 	struct termios t;
264 	tcgetattr (FD, &t);
265 	if (flag)
266 		t.c_cflag |= CLOCAL;
267 	else
268 		t.c_cflag &= ~CLOCAL;
269 	tcsetattr (FD, TCSANOW, &t);
270 }
271 
272 static int
273 unidialer_get_modem_response(char *buf, int bufsz, int response_timeout)
274 {
275 	sig_t f;
276 	char c, *p = buf, *lid = buf + bufsz - 1;
277 	int state;
278 
279 	assert (bufsz > 0);
280 
281 	f = signal (SIGALRM, sigALRM);
282 
283 	timeout = 0;
284 
285 	if (setjmp (timeoutbuf)) {
286 		signal (SIGALRM, f);
287 		*p = '\0';
288 #ifdef DEBUG
289 		printf ("get_response: timeout buf=%s\n", buf);
290 #endif
291 		return (0);
292 	}
293 
294 	ualarm (response_timeout * 1000, 0);
295 
296 	state = 0;
297 
298 	while (1)
299 	{
300 		switch (state)
301 		{
302 			case 0:
303 				if (read (FD, &c, 1) == 1)
304 				{
305 					if (c == '\r')
306 					{
307 						++state;
308 					}
309 					else
310 					{
311 #ifdef DEBUG
312 						printf ("get_response: unexpected char %s.\n", ctrl (c));
313 #endif
314 					}
315 				}
316 				break;
317 
318 			case 1:
319 				if (read (FD, &c, 1) == 1)
320 				{
321 					if (c == '\n')
322 					{
323 #ifdef DEBUG
324 						printf ("get_response: <CRLF> encountered.\n");
325 #endif
326 						++state;
327 					}
328 					else
329 					{
330 							state = 0;
331 #ifdef DEBUG
332 							printf ("get_response: unexpected char %s.\n", ctrl (c));
333 #endif
334 					}
335 				}
336 				break;
337 
338 			case 2:
339 				if (read (FD, &c, 1) == 1)
340 				{
341 					if (c == '\r')
342 						++state;
343 					else if (c >= ' ' && p < lid)
344 						*p++ = c;
345 				}
346 				break;
347 
348 			case 3:
349 				if (read (FD, &c, 1) == 1)
350 				{
351 					if (c == '\n')
352 					{
353 						signal (SIGALRM, f);
354 						/* ualarm (0, 0); */
355 						alarm (0);
356 						*p = '\0';
357 #ifdef DEBUG
358 						printf ("get_response: %s\n", buf);
359 #endif
360 						return (1);
361 					}
362 					else
363 					{
364 						state = 0;
365 						p = buf;
366 					}
367 				}
368 				break;
369 		}
370 	}
371 }
372 
373 static int
374 unidialer_get_okay(int ms)
375 {
376 	int okay;
377 	char buf [BUFSIZ];
378 	okay = unidialer_get_modem_response (buf, sizeof (buf), ms) &&
379 		strcmp (buf, "OK") == 0;
380 	return okay;
381 }
382 
383 static int
384 unidialer_dialer(char *num, char *acu)
385 {
386 	char *cp;
387 	char dial_string [80];
388 	char line [80];
389 
390 #ifdef DEBUG
391 	dumpmodemparms (modem_name);
392 #endif
393 
394 	if (lock_baud) {
395 		int i;
396 		if ((i = speed(number(value(BAUDRATE)))) == 0)
397 			return 0;
398 		ttysetup (i);
399 	}
400 
401 	if (boolean(value(VERBOSE)))
402 		printf("Using \"%s\"\n", acu);
403 
404 	acu_hupcl ();
405 
406 	/*
407 	 * Get in synch.
408 	 */
409 	if (!unidialersync()) {
410 badsynch:
411 		printf("tip: can't synchronize with %s\n", modem_name);
412 		logent(value(HOST), num, modem_name, "can't synch up");
413 		return (0);
414 	}
415 
416 	unidialer_modem_cmd (FD, echo_off_command);	/* turn off echoing */
417 
418 	sleep(1);
419 
420 #ifdef DEBUG
421 	if (boolean(value(VERBOSE)))
422 		unidialer_verbose_read();
423 #endif
424 
425 	acu_flush (); /* flush any clutter */
426 
427 	unidialer_modem_cmd (FD, init_string);
428 
429 	if (!unidialer_get_okay (reset_delay))
430 		goto badsynch;
431 
432 	fflush (stdout);
433 
434 	for (cp = num; *cp; cp++)
435 		if (*cp == '=')
436 			*cp = ',';
437 
438 	(void) sprintf (dial_string, dial_command, num);
439 
440 	unidialer_modem_cmd (FD, dial_string);
441 
442 	connected = unidialer_connect ();
443 
444 	if (connected && hw_flow_control) {
445 		acu_hw_flow_control (hw_flow_control);
446 	}
447 
448 	if (timeout) {
449 		sprintf(line, "%d second dial timeout",
450 			number(value(DIALTIMEOUT)));
451 		logent(value(HOST), num, modem_name, line);
452 	}
453 
454 	if (timeout)
455 		unidialer_disconnect ();
456 
457 	return (connected);
458 }
459 
460 static void
461 unidialer_disconnect(void)
462 {
463 	int okay, retries;
464 
465 	acu_flush (); /* flush any clutter */
466 
467 	unidialer_tty_clocal (TRUE);
468 
469  	/* first hang up the modem*/
470 	ioctl (FD, TIOCCDTR, 0);
471 	acu_nap (250);
472 	ioctl (FD, TIOCSDTR, 0);
473 
474 	/*
475 	 * If AT&D2, then dropping DTR *should* just hangup the modem. But
476 	 * some modems reset anyway; also, the modem may be programmed to reset
477 	 * anyway with AT&D3. Play it safe and wait for the full reset time before
478 	 * proceeding.
479 	 */
480 	acu_nap (reset_delay);
481 
482 	if (!unidialer_waitfor_modem_ready (reset_delay))
483 	{
484 #ifdef DEBUG
485 			printf ("unidialer_disconnect: warning CTS low.\r\n");
486 #endif
487 	}
488 
489 	/*
490 	 * If not strapped for DTR control, try to get command mode.
491 	 */
492 	for (retries = okay = 0; retries < MAXRETRY && !okay; retries++)
493 	{
494 		int timeout_value;
495 		/* flush any clutter */
496 		if (!acu_flush ())
497 		{
498 #ifdef DEBUG
499 			printf ("unidialer_disconnect: warning flush failed.\r\n");
500 #endif
501 		}
502 		timeout_value = escape_guard_time;
503 		timeout_value += (timeout_value * retries / MAXRETRY);
504 		acu_nap (timeout_value);
505 		acu_flush (); /* flush any clutter */
506 		unidialer_modem_cmd (FD, escape_sequence);
507 		acu_nap (timeout_value);
508 		unidialer_modem_cmd (FD, hangup_command);
509 		okay = unidialer_get_okay (reset_delay);
510 	}
511 	if (!okay)
512 	{
513 		logent(value(HOST), "", modem_name, "can't hang up modem");
514 		if (boolean(value(VERBOSE)))
515 			printf("hang up failed\n");
516 	}
517 	(void) acu_flush ();
518 	close (FD);
519 }
520 
521 static void
522 unidialer_abort(void)
523 {
524 	unidialer_write_str (FD, "\r");	/* send anything to abort the call */
525 	unidialer_disconnect ();
526 }
527 
528 static void
529 sigALRM(int signo)
530 {
531 	(void) printf("\07timeout waiting for reply\n");
532 	timeout = 1;
533 	longjmp(timeoutbuf, 1);
534 }
535 
536 static int unidialer_swallow (char *match)
537 {
538 	sig_t f;
539 	char c;
540 
541 	f = signal(SIGALRM, sigALRM);
542 
543 	timeout = 0;
544 
545 	if (setjmp(timeoutbuf)) {
546 		signal(SIGALRM, f);
547 		return (0);
548 	}
549 
550 	alarm(number(value(DIALTIMEOUT)));
551 
552 	do {
553 		if (*match =='\0') {
554 			signal(SIGALRM, f);
555 			alarm (0);
556 			return (1);
557 		}
558 		do {
559 			read (FD, &c, 1);
560 		} while (c == '\0');
561 		c &= 0177;
562 #ifdef DEBUG
563 		if (boolean(value(VERBOSE)))
564 		{
565 			/* putchar(c); */
566 			printf (ctrl (c));
567 		}
568 #endif
569 	} while (c == *match++);
570 	signal(SIGALRM, SIG_DFL);
571 	alarm(0);
572 #ifdef DEBUG
573 	if (boolean(value(VERBOSE)))
574 		fflush (stdout);
575 #endif
576 	return (0);
577 }
578 
579 static struct baud_msg {
580 	char *msg;
581 	int baud;
582 } baud_msg[] = {
583 	{ "",		B300 },
584 	{ " 1200",	B1200 },
585 	{ " 2400",	B2400 },
586 	{ " 9600",	B9600 },
587 	{ " 9600/ARQ",	B9600 },
588 	{ 0,		0 },
589 };
590 
591 static int
592 unidialer_connect(void)
593 {
594 	char c;
595 	int nc, nl, n;
596 	char dialer_buf[64];
597 	struct baud_msg *bm;
598 	sig_t f;
599 
600 	if (unidialer_swallow("\r\n") == 0)
601 		return (0);
602 	f = signal(SIGALRM, sigALRM);
603 again:
604 	nc = 0; nl = sizeof(dialer_buf)-1;
605 	bzero(dialer_buf, sizeof(dialer_buf));
606 	timeout = 0;
607 	for (nc = 0, nl = sizeof(dialer_buf)-1 ; nl > 0 ; nc++, nl--) {
608 		if (setjmp(timeoutbuf))
609 			break;
610 		alarm(number(value(DIALTIMEOUT)));
611 		n = read(FD, &c, 1);
612 		alarm(0);
613 		if (n <= 0)
614 			break;
615 		c &= 0x7f;
616 		if (c == '\r') {
617 			if (unidialer_swallow("\n") == 0)
618 				break;
619 			if (!dialer_buf[0])
620 				goto again;
621 			if (strcmp(dialer_buf, "RINGING") == 0 &&
622 			    boolean(value(VERBOSE))) {
623 #ifdef DEBUG
624 				printf("%s\r\n", dialer_buf);
625 #endif
626 				goto again;
627 			}
628 			if (strncmp(dialer_buf, "CONNECT",
629 				    sizeof("CONNECT")-1) != 0)
630 				break;
631 			if (lock_baud) {
632 				signal(SIGALRM, f);
633 #ifdef DEBUG
634 				if (boolean(value(VERBOSE)))
635 					printf("%s\r\n", dialer_buf);
636 #endif
637 				return (1);
638 			}
639 			for (bm = baud_msg ; bm->msg ; bm++)
640 				if (strcmp(bm->msg, dialer_buf+sizeof("CONNECT")-1) == 0) {
641 					if (!acu_setspeed (bm->baud))
642 						goto error;
643 					signal(SIGALRM, f);
644 #ifdef DEBUG
645 					if (boolean(value(VERBOSE)))
646 						printf("%s\r\n", dialer_buf);
647 #endif
648 					return (1);
649 				}
650 			break;
651 		}
652 		dialer_buf[nc] = c;
653 	}
654 	printf("%s\r\n", dialer_buf);
655 error:
656 	signal(SIGALRM, f);
657 	return (0);
658 }
659 
660 /*
661  * This convoluted piece of code attempts to get
662  * the unidialer in sync.
663  */
664 static int
665 unidialersync(void)
666 {
667 	int already = 0;
668 	int len;
669 	char buf[40];
670 
671 	while (already++ < MAXRETRY) {
672 		acu_nap (intercommand_delay);
673 		acu_flush (); /* flush any clutter */
674 		unidialer_write_str (FD, reset_command); /* reset modem */
675 		bzero(buf, sizeof(buf));
676 		acu_nap (reset_delay);
677 		ioctl (FD, FIONREAD, &len);
678 		if (len) {
679 			len = read(FD, buf, sizeof(buf));
680 #ifdef DEBUG
681 			buf [len] = '\0';
682 			printf("unidialersync (%s): (\"%s\")\n\r", modem_name, buf);
683 #endif
684 			if (index(buf, '0') ||
685 		   	   (index(buf, 'O') && index(buf, 'K')))
686 				return(1);
687 		}
688 		/*
689 		 * If not strapped for DTR control,
690 		 * try to get command mode.
691 		 */
692 		acu_nap (escape_guard_time);
693 		unidialer_write_str (FD, escape_sequence);
694 		acu_nap (escape_guard_time);
695 		unidialer_write_str (FD, hangup_command);
696 		/*
697 		 * Toggle DTR to force anyone off that might have left
698 		 * the modem connected.
699 		 */
700 		acu_nap (escape_guard_time);
701 		ioctl (FD, TIOCCDTR, 0);
702 		acu_nap (1000);
703 		ioctl (FD, TIOCSDTR, 0);
704 	}
705 	acu_nap (intercommand_delay);
706 	unidialer_write_str (FD, reset_command);
707 	return (0);
708 }
709 
710 /*
711 	Send commands to modem; impose delay between commands.
712 */
713 static void unidialer_modem_cmd (int fd, const char *cmd)
714 {
715 	static struct timeval oldt = { 0, 0 };
716 	struct timeval newt;
717 	tod_gettime (&newt);
718 	if (tod_lt (&newt, &oldt))
719 	{
720 		unsigned int naptime;
721 		tod_subfrom (&oldt, newt);
722 		naptime = oldt.tv_sec * 1000 + oldt.tv_usec / 1000;
723 		if (naptime > intercommand_delay)
724 		{
725 #ifdef DEBUG
726 		printf ("unidialer_modem_cmd: suspicious naptime (%u ms)\r\n", naptime);
727 #endif
728 			naptime = intercommand_delay;
729 		}
730 #ifdef DEBUG
731 		printf ("unidialer_modem_cmd: delaying %u ms\r\n", naptime);
732 #endif
733 		acu_nap (naptime);
734 	}
735 	unidialer_write_str (fd, cmd);
736 	tod_gettime (&oldt);
737 	newt.tv_sec = 0;
738 	newt.tv_usec = intercommand_delay;
739 	tod_addto (&oldt, &newt);
740 }
741 
742 static void unidialer_write_str (int fd, const char *cp)
743 {
744 #ifdef DEBUG
745 	printf ("unidialer (%s): sending %s\n", modem_name, cp);
746 #endif
747 	unidialer_write (fd, cp, strlen (cp));
748 }
749 
750 static void unidialer_write (int fd, const char *cp, int n)
751 {
752 	acu_nap (intercharacter_delay);
753 	for ( ; n-- ; cp++) {
754 		write (fd, cp, 1);
755 		acu_nap (intercharacter_delay);
756 	}
757 }
758 
759 #ifdef DEBUG
760 static void unidialer_verbose_read(void)
761 {
762 	int n = 0;
763 	char buf[BUFSIZ];
764 
765 	if (ioctl(FD, FIONREAD, &n) < 0)
766 		return;
767 	if (n <= 0)
768 		return;
769 	if (read(FD, buf, n) != n)
770 		return;
771 	write(1, buf, n);
772 }
773 #endif
774 
775 /* end of unidialer.c */
776