xref: /freebsd/usr.bin/tip/tip/tip.c (revision 0957b409) 
1 /*	$OpenBSD: tip.c,v 1.30 2006/08/18 03:06:18 jason Exp $	*/
2 /*	$NetBSD: tip.c,v 1.13 1997/04/20 00:03:05 mellon Exp $	*/
3 
4 /*-
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Copyright (c) 1983, 1993
8  *	The Regents of the University of California.  All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #ifndef lint
39 static const char copyright[] =
40 "@(#) Copyright (c) 1983, 1993\n\
41 	The Regents of the University of California.  All rights reserved.\n";
42 #endif /* not lint */
43 
44 #ifndef lint
45 #if 0
46 static char sccsid[] = "@(#)tip.c	8.1 (Berkeley) 6/6/93";
47 static const char rcsid[] = "$OpenBSD: tip.c,v 1.30 2006/08/18 03:06:18 jason Exp $";
48 #endif
49 #endif /* not lint */
50 
51 /*
52  * tip - UNIX link to other systems
53  *  tip [-v] [-speed] system-name
54  * or
55  *  cu phone-number [-s speed] [-l line] [-a acu]
56  */
57 #include "tip.h"
58 #include "pathnames.h"
59 
60 int	disc = TTYDISC;		/* tip normally runs this way */
61 char	PNbuf[256];			/* This limits the size of a number */
62 
63 static void	intprompt(int);
64 static void	tipin(void);
65 static int	escape(void);
66 
67 int
68 main(int argc, char *argv[])
69 {
70 	char *sys = NOSTR, sbuf[12], *p;
71 	int i;
72 
73 	/* XXX preserve previous braindamaged behavior */
74 	setboolean(value(DC), TRUE);
75 
76 	gid = getgid();
77 	egid = getegid();
78 	uid = getuid();
79 	euid = geteuid();
80 	if (equal(__progname, "cu")) {
81 		cumode = 1;
82 		cumain(argc, argv);
83 		goto cucommon;
84 	}
85 
86 	if (argc > 4) {
87 		fprintf(stderr, "usage: tip [-v] [-speed] [system-name]\n");
88 		exit(1);
89 	}
90 	if (!isatty(0)) {
91 		fprintf(stderr, "%s: must be interactive\n", __progname);
92 		exit(1);
93 	}
94 
95 	for (; argc > 1; argv++, argc--) {
96 		if (argv[1][0] != '-')
97 			sys = argv[1];
98 		else switch (argv[1][1]) {
99 
100 		case 'v':
101 			vflag++;
102 			break;
103 
104 		case 'n':
105 			noesc++;
106 			break;
107 
108 		case '0': case '1': case '2': case '3': case '4':
109 		case '5': case '6': case '7': case '8': case '9':
110 			BR = atoi(&argv[1][1]);
111 			break;
112 
113 		default:
114 			fprintf(stderr, "%s: %s, unknown option\n", __progname,
115 			    argv[1]);
116 			break;
117 		}
118 	}
119 
120 	if (sys == NOSTR)
121 		goto notnumber;
122 	if (isalpha(*sys))
123 		goto notnumber;
124 	/*
125 	 * System name is really a phone number...
126 	 * Copy the number then stomp on the original (in case the number
127 	 *	is private, we don't want 'ps' or 'w' to find it).
128 	 */
129 	if (strlen(sys) > sizeof PNbuf - 1) {
130 		fprintf(stderr, "%s: phone number too long (max = %d bytes)\n",
131 			__progname, (int)sizeof(PNbuf) - 1);
132 		exit(1);
133 	}
134 	strlcpy(PNbuf, sys, sizeof PNbuf - 1);
135 	for (p = sys; *p; p++)
136 		*p = '\0';
137 	PN = PNbuf;
138 	(void)snprintf(sbuf, sizeof(sbuf), "tip%ld", BR);
139 	sys = sbuf;
140 
141 notnumber:
142 	(void)signal(SIGINT, cleanup);
143 	(void)signal(SIGQUIT, cleanup);
144 	(void)signal(SIGHUP, cleanup);
145 	(void)signal(SIGTERM, cleanup);
146 	(void)signal(SIGCHLD, SIG_DFL);
147 
148 	if ((i = hunt(sys)) == 0) {
149 		printf("all ports busy\n");
150 		exit(3);
151 	}
152 	if (i == -1) {
153 		printf("link down\n");
154 		(void)uu_unlock(uucplock);
155 		exit(3);
156 	}
157 	setbuf(stdout, NULL);
158 	loginit();
159 
160 	/*
161 	 * Now that we have the logfile and the ACU open
162 	 *  return to the real uid and gid.  These things will
163 	 *  be closed on exit.  Swap real and effective uid's
164 	 *  so we can get the original permissions back
165 	 *  for removing the uucp lock.
166 	 */
167 	user_uid();
168 
169 	/*
170 	 * Kludge, their's no easy way to get the initialization
171 	 *   in the right order, so force it here
172 	 */
173 	if ((PH = getenv("PHONES")) == NOSTR)
174 		PH = _PATH_PHONES;
175 	vinit();				/* init variables */
176 	setparity("none");			/* set the parity table */
177 
178 	/*
179 	 * Hardwired connections require the
180 	 *  line speed set before they make any transmissions
181 	 *  (this is particularly true of things like a DF03-AC)
182 	 */
183 	if (HW && ttysetup(number(value(BAUDRATE)))) {
184 		fprintf(stderr, "%s: bad baud rate %ld\n", __progname,
185 		    number(value(BAUDRATE)));
186 		daemon_uid();
187 		(void)uu_unlock(uucplock);
188 		exit(3);
189 	}
190 	if ((p = con())) {
191 		printf("\07%s\n[EOT]\n", p);
192 		daemon_uid();
193 		(void)uu_unlock(uucplock);
194 		exit(1);
195 	}
196 	if (!HW && ttysetup(number(value(BAUDRATE)))) {
197 		fprintf(stderr, "%s: bad baud rate %ld\n", __progname,
198 		    number(value(BAUDRATE)));
199 		daemon_uid();
200 		(void)uu_unlock(uucplock);
201 		exit(3);
202 	}
203 cucommon:
204 	/*
205 	 * From here down the code is shared with
206 	 * the "cu" version of tip.
207 	 */
208 
209 	i = fcntl(FD, F_GETFL);
210 	if (i == -1) {
211 		perror("fcntl");
212 		cleanup(0);
213 	}
214 	i = fcntl(FD, F_SETFL, i & ~O_NONBLOCK);
215 	if (i == -1) {
216 		perror("fcntl");
217 		cleanup(0);
218 	}
219 
220 	tcgetattr(0, &defterm);
221 	gotdefterm = 1;
222 	term = defterm;
223 	term.c_lflag &= ~(ICANON|IEXTEN|ECHO);
224 	term.c_iflag &= ~(INPCK|ICRNL);
225 	term.c_oflag &= ~OPOST;
226 	term.c_cc[VMIN] = 1;
227 	term.c_cc[VTIME] = 0;
228 	defchars = term;
229 	term.c_cc[VINTR] = term.c_cc[VQUIT] = term.c_cc[VSUSP] =
230 	    term.c_cc[VDSUSP] = term.c_cc[VDISCARD] =
231 	    term.c_cc[VLNEXT] = _POSIX_VDISABLE;
232 	raw();
233 
234 	pipe(fildes); pipe(repdes);
235 	(void)signal(SIGALRM, timeout);
236 
237 	if (value(LINEDISC) != TTYDISC) {
238 		int ld = (int)(intptr_t)value(LINEDISC);
239 		ioctl(FD, TIOCSETD, &ld);
240 	}
241 
242 	/*
243 	 * Everything's set up now:
244 	 *	connection established (hardwired or dialup)
245 	 *	line conditioned (baud rate, mode, etc.)
246 	 *	internal data structures (variables)
247 	 * so, fork one process for local side and one for remote.
248 	 */
249 	printf(cumode ? "Connected\r\n" : "\07connected\r\n");
250 	tipin_pid = getpid();
251 	if ((tipout_pid = fork()))
252 		tipin();
253 	else
254 		tipout();
255 	/*NOTREACHED*/
256 	exit(0);
257 }
258 
259 void
260 cleanup(int signo)
261 {
262 	daemon_uid();
263 	(void)uu_unlock(uucplock);
264 	if (odisc)
265 		ioctl(0, TIOCSETD, &odisc);
266 	unraw();
267 	if (signo && tipout_pid) {
268 		kill(tipout_pid, signo);
269 		wait(NULL);
270 	}
271 	exit(0);
272 }
273 
274 /*
275  * Muck with user ID's.  We are setuid to the owner of the lock
276  * directory when we start.  user_uid() reverses real and effective
277  * ID's after startup, to run with the user's permissions.
278  * daemon_uid() switches back to the privileged uid for unlocking.
279  * Finally, to avoid running a shell with the wrong real uid,
280  * shell_uid() sets real and effective uid's to the user's real ID.
281  */
282 static int uidswapped;
283 
284 void
285 user_uid(void)
286 {
287 	if (uidswapped == 0) {
288 		seteuid(uid);
289 		uidswapped = 1;
290 	}
291 }
292 
293 void
294 daemon_uid(void)
295 {
296 
297 	if (uidswapped) {
298 		seteuid(euid);
299 		uidswapped = 0;
300 	}
301 }
302 
303 void
304 shell_uid(void)
305 {
306 	setegid(gid);
307 	seteuid(uid);
308 }
309 
310 /*
311  * put the controlling keyboard into raw mode
312  */
313 void
314 raw(void)
315 {
316 	tcsetattr(0, TCSADRAIN, &term);
317 }
318 
319 
320 /*
321  * return keyboard to normal mode
322  */
323 void
324 unraw(void)
325 {
326 	if (gotdefterm)
327 		tcsetattr(0, TCSADRAIN, &defterm);
328 }
329 
330 /*
331  * give up exclusive tty access
332  */
333 void
334 unexcl()
335 {
336 	ioctl(FD, TIOCNXCL, 0);
337 }
338 
339 static	jmp_buf promptbuf;
340 
341 /*
342  * Print string ``s'', then read a string
343  *  in from the terminal.  Handles signals & allows use of
344  *  normal erase and kill characters.
345  */
346 int
347 prompt(char *s, char *p, size_t sz)
348 {
349 	int c;
350 	char *b = p;
351 	sig_t oint, oquit;
352 
353 	stoprompt = 0;
354 	oint = signal(SIGINT, intprompt);
355 	oquit = signal(SIGQUIT, SIG_IGN);
356 	unraw();
357 	printf("%s", s);
358 	if (setjmp(promptbuf) == 0)
359 		while ((c = getchar()) != EOF && (*p = c) != '\n' && --sz > 0)
360 			p++;
361 	*p = '\0';
362 
363 	raw();
364 	(void)signal(SIGINT, oint);
365 	(void)signal(SIGQUIT, oquit);
366 	return (stoprompt || p == b);
367 }
368 
369 /*
370  * Interrupt service routine during prompting
371  */
372 /*ARGSUSED*/
373 static void
374 intprompt(int signo)
375 {
376 	(void)signal(SIGINT, SIG_IGN);
377 	stoprompt = 1;
378 	printf("\r\n");
379 	longjmp(promptbuf, 1);
380 }
381 
382 /*
383  * ****TIPIN   TIPIN****
384  */
385 static void
386 tipin(void)
387 {
388 	int bol = 1;
389 	int gch;
390 	char ch;
391 
392 	/*
393 	 * Kinda klugey here...
394 	 *   check for scripting being turned on from the .tiprc file,
395 	 *   but be careful about just using setscript(), as we may
396 	 *   send a SIGEMT before tipout has a chance to set up catching
397 	 *   it; so wait a second, then setscript()
398 	 */
399 	if (boolean(value(SCRIPT))) {
400 		sleep(1);
401 		setscript();
402 	}
403 
404 	while (1) {
405 		gch = getchar()&STRIP_PAR;
406 		/* XXX does not check for EOF */
407 		if ((gch == character(value(ESCAPE))) && bol) {
408 			if (!noesc) {
409 				if (!(gch = escape()))
410 					continue;
411 			}
412 		} else if (!cumode && gch == character(value(RAISECHAR))) {
413 			setboolean(value(RAISE), !boolean(value(RAISE)));
414 			continue;
415 		} else if (gch == '\r') {
416 			bol = 1;
417 			ch = gch;
418 			parwrite(FD, &ch, 1);
419 			if (boolean(value(HALFDUPLEX)))
420 				printf("\r\n");
421 			continue;
422 		} else if (!cumode && gch == character(value(FORCE)))
423 			gch = getchar()&STRIP_PAR;
424 		bol = any(gch, value(EOL));
425 		if (boolean(value(RAISE)) && islower(gch))
426 			gch = toupper(gch);
427 		ch = gch;
428 		parwrite(FD, &ch, 1);
429 		if (boolean(value(HALFDUPLEX)))
430 			printf("%c", ch);
431 	}
432 }
433 
434 extern esctable_t etable[];
435 
436 /*
437  * Escape handler --
438  *  called on recognition of ``escapec'' at the beginning of a line
439  */
440 static int
441 escape(void)
442 {
443 	int gch;
444 	esctable_t *p;
445 	char c = character(value(ESCAPE));
446 
447 	gch = (getchar()&STRIP_PAR);
448 	/* XXX does not check for EOF */
449 	for (p = etable; p->e_char; p++)
450 		if (p->e_char == gch) {
451 			if ((p->e_flags&PRIV) && uid)
452 				continue;
453 			printf("%s", ctrl(c));
454 			(*p->e_func)(gch);
455 			return (0);
456 		}
457 	/* ESCAPE ESCAPE forces ESCAPE */
458 	if (c != gch)
459 		parwrite(FD, &c, 1);
460 	return (gch);
461 }
462 
463 int
464 any(int cc, char *p)
465 {
466 	char c = cc;
467 	while (p && *p)
468 		if (*p++ == c)
469 			return (1);
470 	return (0);
471 }
472 
473 size_t
474 size(char *s)
475 {
476 	size_t i = 0;
477 
478 	while (s && *s++)
479 		i++;
480 	return (i);
481 }
482 
483 char *
484 interp(char *s)
485 {
486 	static char buf[256];
487 	char *p = buf, c, *q;
488 
489 	while ((c = *s++)) {
490 		for (q = "\nn\rr\tt\ff\033E\bb"; *q; q++)
491 			if (*q++ == c) {
492 				*p++ = '\\'; *p++ = *q;
493 				goto next;
494 			}
495 		if (c < 040) {
496 			*p++ = '^'; *p++ = c + 'A'-1;
497 		} else if (c == 0177) {
498 			*p++ = '^'; *p++ = '?';
499 		} else
500 			*p++ = c;
501 	next:
502 		;
503 	}
504 	*p = '\0';
505 	return (buf);
506 }
507 
508 char *
509 ctrl(char c)
510 {
511 	static char s[3];
512 
513 	if (c < 040 || c == 0177) {
514 		s[0] = '^';
515 		s[1] = c == 0177 ? '?' : c+'A'-1;
516 		s[2] = '\0';
517 	} else {
518 		s[0] = c;
519 		s[1] = '\0';
520 	}
521 	return (s);
522 }
523 
524 /*
525  * Help command
526  */
527 void
528 help(int c)
529 {
530 	esctable_t *p;
531 
532 	printf("%c\r\n", c);
533 	for (p = etable; p->e_char; p++) {
534 		if ((p->e_flags&PRIV) && uid)
535 			continue;
536 		printf("%2s", ctrl(character(value(ESCAPE))));
537 		printf("%-2s %c   %s\r\n", ctrl(p->e_char),
538 			p->e_flags&EXP ? '*': ' ', p->e_help);
539 	}
540 }
541 
542 /*
543  * Set up the "remote" tty's state
544  */
545 int
546 ttysetup(int speed)
547 {
548 	struct termios	cntrl;
549 
550 	if (tcgetattr(FD, &cntrl))
551 		return (-1);
552 	cfsetspeed(&cntrl, speed);
553 	cntrl.c_cflag &= ~(CSIZE|PARENB);
554 	cntrl.c_cflag |= CS8;
555 	if (boolean(value(DC)))
556 		cntrl.c_cflag |= CLOCAL;
557 	if (boolean(value(HARDWAREFLOW)))
558 		cntrl.c_cflag |= CRTSCTS;
559 	cntrl.c_iflag &= ~(ISTRIP|ICRNL);
560 	cntrl.c_oflag &= ~OPOST;
561 	cntrl.c_lflag &= ~(ICANON|ISIG|IEXTEN|ECHO);
562 	cntrl.c_cc[VMIN] = 1;
563 	cntrl.c_cc[VTIME] = 0;
564 	if (boolean(value(TAND)))
565 		cntrl.c_iflag |= IXOFF;
566 	return (tcsetattr(FD, TCSAFLUSH, &cntrl));
567 }
568 
569 static char partab[0200];
570 
571 /*
572  * Do a write to the remote machine with the correct parity.
573  * We are doing 8 bit wide output, so we just generate a character
574  * with the right parity and output it.
575  */
576 void
577 parwrite(int fd, char *buf, size_t n)
578 {
579 	size_t i;
580 	char *bp;
581 
582 	bp = buf;
583 	if (bits8 == 0)
584 		for (i = 0; i < n; i++) {
585 			*bp = partab[(*bp) & 0177];
586 			bp++;
587 		}
588 	if (write(fd, buf, n) < 0) {
589 		if (errno == EIO || errno == ENXIO)
590 			tipabort("Lost carrier.");
591 		/* this is questionable */
592 		perror("write");
593 	}
594 }
595 
596 /*
597  * Build a parity table with appropriate high-order bit.
598  */
599 void
600 setparity(char *defparity)
601 {
602 	int i, flip, clr, set;
603 	char *parity;
604 	extern const unsigned char evenpartab[];
605 
606 	if (value(PARITY) == NOSTR)
607 		value(PARITY) = defparity;
608 	parity = value(PARITY);
609 	if (equal(parity, "none")) {
610 		bits8 = 1;
611 		return;
612 	}
613 	bits8 = 0;
614 	flip = 0;
615 	clr = 0377;
616 	set = 0;
617 	if (equal(parity, "odd"))
618 		flip = 0200;			/* reverse bit 7 */
619 	else if (equal(parity, "zero"))
620 		clr = 0177;			/* turn off bit 7 */
621 	else if (equal(parity, "one"))
622 		set = 0200;			/* turn on bit 7 */
623 	else if (!equal(parity, "even")) {
624 		(void) fprintf(stderr, "%s: unknown parity value\r\n", parity);
625 		(void) fflush(stderr);
626 	}
627 	for (i = 0; i < 0200; i++)
628 		partab[i] = ((evenpartab[i] ^ flip) | set) & clr;
629 }
630