tty.c revision 1.24 
1/*	$OpenBSD: tty.c,v 1.24 2023/11/03 19:32:28 anton Exp $	*/
2/*	$NetBSD: tty.c,v 1.7 1997/07/09 05:25:46 mikel Exp $	*/
3
4/*
5 * Copyright (c) 1980, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33/*
34 * Mail -- a mail program
35 *
36 * Generally useful tty stuff.
37 */
38
39#include "rcv.h"
40#include "extern.h"
41#include <sys/ioctl.h>
42#include <errno.h>
43#include <fcntl.h>
44
45#define	TABWIDTH	8
46
47struct tty {
48	int	 fdin;
49	int	 fdout;
50	int	 flags;
51#define	TTY_ALTWERASE	0x1
52#define	TTY_ERR		0x2
53	cc_t	*keys;
54	char	*buf;
55	size_t	 size;
56	size_t	 len;
57	size_t	 cursor;
58};
59
60static void	tty_flush(struct tty *);
61static int	tty_getc(struct tty *);
62static int	tty_insert(struct tty *, int, int);
63static void	tty_putc(struct tty *, int);
64static void	tty_reset(struct tty *);
65static void	tty_visc(struct tty *, int);
66
67static struct tty		tty;
68static	volatile sig_atomic_t	ttysignal;	/* Interrupted by a signal? */
69
70/*
71 * Read all relevant header fields.
72 */
73int
74grabh(struct header *hp, int gflags)
75{
76	struct termios newtio, oldtio;
77#ifdef TIOCEXT
78	int extproc;
79	int flag;
80#endif
81	struct sigaction savetstp;
82	struct sigaction savettou;
83	struct sigaction savettin;
84	struct sigaction act;
85	char *s;
86	int error;
87
88	sigemptyset(&act.sa_mask);
89	act.sa_flags = SA_RESTART;
90	act.sa_handler = SIG_DFL;
91	(void)sigaction(SIGTSTP, &act, &savetstp);
92	(void)sigaction(SIGTTOU, &act, &savettou);
93	(void)sigaction(SIGTTIN, &act, &savettin);
94	error = 1;
95	memset(&tty, 0, sizeof(tty));
96	tty.fdin = fileno(stdin);
97	tty.fdout = fileno(stdout);
98	if (tcgetattr(tty.fdin, &oldtio) == -1) {
99		warn("tcgetattr");
100		return(-1);
101	}
102	tty.keys = oldtio.c_cc;
103	if (oldtio.c_lflag & ALTWERASE)
104		tty.flags |= TTY_ALTWERASE;
105
106	newtio = oldtio;
107	newtio.c_lflag &= ~(ECHO | ICANON);
108	newtio.c_cc[VMIN] = 1;
109	newtio.c_cc[VTIME] = 0;
110	if (tcsetattr(tty.fdin, TCSADRAIN, &newtio) == -1) {
111		warn("tcsetattr");
112		return(-1);
113	}
114
115#ifdef TIOCEXT
116	extproc = ((oldtio.c_lflag & EXTPROC) ? 1 : 0);
117	if (extproc) {
118		flag = 0;
119		if (ioctl(fileno(stdin), TIOCEXT, &flag) == -1)
120			warn("TIOCEXT: off");
121	}
122#endif
123	if (gflags & GTO) {
124		s = readtty("To: ", detract(hp->h_to, 0));
125		if (s == NULL)
126			goto out;
127		hp->h_to = extract(s, GTO);
128	}
129	if (gflags & GSUBJECT) {
130		s = readtty("Subject: ", hp->h_subject);
131		if (s == NULL)
132			goto out;
133		hp->h_subject = s;
134	}
135	if (gflags & GCC) {
136		s = readtty("Cc: ", detract(hp->h_cc, 0));
137		if (s == NULL)
138			goto out;
139		hp->h_cc = extract(s, GCC);
140	}
141	if (gflags & GBCC) {
142		s = readtty("Bcc: ", detract(hp->h_bcc, 0));
143		if (s == NULL)
144			goto out;
145		hp->h_bcc = extract(s, GBCC);
146	}
147	error = 0;
148out:
149	(void)sigaction(SIGTSTP, &savetstp, NULL);
150	(void)sigaction(SIGTTOU, &savettou, NULL);
151	(void)sigaction(SIGTTIN, &savettin, NULL);
152#ifdef TIOCEXT
153	if (extproc) {
154		flag = 1;
155		if (ioctl(fileno(stdin), TIOCEXT, &flag) == -1)
156			warn("TIOCEXT: on");
157	}
158#endif
159	if (tcsetattr(tty.fdin, TCSADRAIN, &oldtio) == -1)
160		warn("tcsetattr");
161	return(error);
162}
163
164/*
165 * Read up a header from standard input.
166 * The source string has the preliminary contents to
167 * be read.
168 *
169 */
170char *
171readtty(char *pr, char *src)
172{
173	struct sigaction act, saveint;
174	unsigned char canonb[BUFSIZ];
175	char *cp;
176	sigset_t oset;
177	int c, done;
178
179	memset(canonb, 0, sizeof(canonb));
180	tty.buf = canonb;
181	tty.size = sizeof(canonb) - 1;
182
183	for (cp = pr; *cp != '\0'; cp++)
184		tty_insert(&tty, *cp, 1);
185	tty_flush(&tty);
186	tty_reset(&tty);
187
188	if (src != NULL && strlen(src) > sizeof(canonb) - 2) {
189		puts("too long to edit");
190		return(src);
191	}
192	if (src != NULL) {
193		for (cp = src; *cp != '\0'; cp++)
194			tty_insert(&tty, *cp, 1);
195		tty_flush(&tty);
196	}
197
198	sigemptyset(&act.sa_mask);
199	act.sa_flags = 0;		/* Note: will not restart syscalls */
200	act.sa_handler = ttyint;
201	(void)sigaction(SIGINT, &act, &saveint);
202	act.sa_handler = ttystop;
203	(void)sigaction(SIGTSTP, &act, NULL);
204	(void)sigaction(SIGTTOU, &act, NULL);
205	(void)sigaction(SIGTTIN, &act, NULL);
206	(void)sigprocmask(SIG_UNBLOCK, &intset, &oset);
207	for (;;) {
208		c = tty_getc(&tty);
209		switch (ttysignal) {
210			case SIGINT:
211				tty_visc(&tty, '\003');	/* output ^C */
212				/* FALLTHROUGH */
213			case 0:
214				break;
215			default:
216				ttysignal = 0;
217				goto redo;
218		}
219		if (c == 0) {
220			done = 1;
221		} else if (c == '\n') {
222			tty_putc(&tty, c);
223			done = 1;
224		} else {
225			done = tty_insert(&tty, c, 0);
226			tty_flush(&tty);
227		}
228		if (done)
229			break;
230	}
231	act.sa_handler = SIG_DFL;
232	sigemptyset(&act.sa_mask);
233	act.sa_flags = SA_RESTART;
234	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
235	(void)sigaction(SIGTSTP, &act, NULL);
236	(void)sigaction(SIGTTOU, &act, NULL);
237	(void)sigaction(SIGTTIN, &act, NULL);
238	(void)sigaction(SIGINT, &saveint, NULL);
239	if (tty.flags & TTY_ERR) {
240		if (ttysignal == SIGINT) {
241			ttysignal = 0;
242			return(NULL);	/* user hit ^C */
243		}
244
245redo:
246		cp = strlen(canonb) > 0 ? canonb : NULL;
247		/* XXX - make iterative, not recursive */
248		return(readtty(pr, cp));
249	}
250	if (equal("", canonb))
251		return("");
252	return(savestr(canonb));
253}
254
255/*
256 * Receipt continuation.
257 */
258void
259ttystop(int s)
260{
261	struct sigaction act, oact;
262	sigset_t nset;
263	int save_errno;
264
265	/*
266	 * Save old handler and set to default.
267	 * Unblock receipt of 's' and then resend it.
268	 */
269	save_errno = errno;
270	(void)sigemptyset(&act.sa_mask);
271	act.sa_flags = SA_RESTART;
272	act.sa_handler = SIG_DFL;
273	(void)sigaction(s, &act, &oact);
274	(void)sigemptyset(&nset);
275	(void)sigaddset(&nset, s);
276	(void)sigprocmask(SIG_UNBLOCK, &nset, NULL);
277	(void)kill(0, s);
278	(void)sigprocmask(SIG_BLOCK, &nset, NULL);
279	(void)sigaction(s, &oact, NULL);
280	ttysignal = s;
281	errno = save_errno;
282}
283
284void
285ttyint(int s)
286{
287
288	ttysignal = s;
289}
290
291static void
292tty_flush(struct tty *t)
293{
294	size_t	i, len;
295	int	c;
296
297	if (t->cursor < t->len) {
298		for (; t->cursor < t->len; t->cursor++)
299			tty_visc(t, t->buf[t->cursor]);
300	} else if (t->cursor > t->len) {
301		len = t->cursor - t->len;
302		for (i = len; i > 0; i--) {
303			c = t->buf[--t->cursor];
304			if (c == '\t')
305				len += TABWIDTH - 1;
306			else if (iscntrl(c))
307				len++;	/* account for leading ^ */
308		}
309		for (i = 0; i < len; i++)
310			tty_putc(t, '\b');
311		for (i = 0; i < len; i++)
312			tty_putc(t, ' ');
313		for (i = 0; i < len; i++)
314			tty_putc(t, '\b');
315		t->cursor = t->len;
316	}
317
318	t->buf[t->len] = '\0';
319}
320
321static int
322tty_getc(struct tty *t)
323{
324	ssize_t		n;
325	unsigned char	c;
326
327	if (ttysignal != 0)
328		n = -1;
329	else
330		n = read(t->fdin, &c, 1);
331	switch (n) {
332	case -1:
333		t->flags |= TTY_ERR;
334		/* FALLTHROUGH */
335	case 0:
336		return 0;
337	default:
338		return c & 0x7f;
339	}
340}
341
342static int
343tty_insert(struct tty *t, int c, int nocntrl)
344{
345	const unsigned char	*ws = " \t";
346
347	if (CCEQ(t->keys[VERASE], c)) {
348		if (nocntrl)
349			return 0;
350		if (t->len > 0)
351			t->len--;
352	} else if (CCEQ(t->keys[VWERASE], c)) {
353		if (nocntrl)
354			return 0;
355		for (; t->len > 0; t->len--)
356			if (strchr(ws, t->buf[t->len - 1]) == NULL
357			    && ((t->flags & TTY_ALTWERASE) == 0
358				    || isalpha(t->buf[t->len - 1])))
359				break;
360		for (; t->len > 0; t->len--)
361			if (strchr(ws, t->buf[t->len - 1]) != NULL
362			    || ((t->flags & TTY_ALTWERASE)
363				    && !isalpha(t->buf[t->len - 1])))
364				break;
365	} else if (CCEQ(t->keys[VKILL], c)) {
366		if (nocntrl)
367			return 0;
368		t->len = 0;
369	} else {
370		if (t->len == t->size)
371			return 1;
372		t->buf[t->len++] = c;
373	}
374
375	return 0;
376}
377
378static void
379tty_putc(struct tty *t, int c)
380{
381	unsigned char	cc = c;
382
383	write(t->fdout, &cc, 1);
384}
385
386static void
387tty_reset(struct tty *t)
388{
389	memset(t->buf, 0, t->len);
390	t->len = t->cursor = 0;
391}
392
393static void
394tty_visc(struct tty *t, int c)
395{
396	int	i;
397
398	if (c == '\t') {
399		for (i = 0; i < TABWIDTH; i++)
400			tty_putc(t, ' ');
401	} else if (iscntrl(c)) {
402		tty_putc(t, '^');
403		if (c == 0x7F)
404			tty_putc(t, '?');
405		else
406			tty_putc(t, (c | 0x40));
407	} else {
408		tty_putc(t, c);
409	}
410}
411