1/*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28/*
29 *	Author: David B. Golub, Carnegie Mellon University
30 *	Date:	7/90
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/cons.h>
39
40#include <ddb/ddb.h>
41#include <ddb/db_output.h>
42
43/*
44 * Character input and editing.
45 */
46
47/*
48 * We don't track output position while editing input,
49 * since input always ends with a new-line.  We just
50 * reset the line position at the end.
51 */
52static char *	db_lbuf_start;	/* start of input line buffer */
53static char *	db_lbuf_end;	/* end of input line buffer */
54static char *	db_lc;		/* current character */
55static char *	db_le;		/* one past last character */
56
57/*
58 * Simple input line history support.
59 */
60static char	db_lhistory[2048];
61static int	db_lhistlsize, db_lhistidx, db_lhistcur;
62static int	db_lhist_nlines;
63
64#define	CTRL(c)		((c) & 0x1f)
65#define	BLANK		' '
66#define	BACKUP		'\b'
67
68static int	cnmaygetc(void);
69static void	db_delete(int n, int bwd);
70static int	db_inputchar(int c);
71static void	db_putnchars(int c, int count);
72static void	db_putstring(char *s, int count);
73
74static void
75db_putstring(s, count)
76	char	*s;
77	int	count;
78{
79	while (--count >= 0)
80	    cnputc(*s++);
81}
82
83static void
84db_putnchars(c, count)
85	int	c;
86	int	count;
87{
88	while (--count >= 0)
89	    cnputc(c);
90}
91
92/*
93 * Delete N characters, forward or backward
94 */
95#define	DEL_FWD		0
96#define	DEL_BWD		1
97static void
98db_delete(n, bwd)
99	int	n;
100	int	bwd;
101{
102	char *p;
103
104	if (bwd) {
105	    db_lc -= n;
106	    db_putnchars(BACKUP, n);
107	}
108	for (p = db_lc; p < db_le-n; p++) {
109	    *p = *(p+n);
110	    cnputc(*p);
111	}
112	db_putnchars(BLANK, n);
113	db_putnchars(BACKUP, db_le - db_lc);
114	db_le -= n;
115}
116
117/* returns true at end-of-line */
118static int
119db_inputchar(c)
120	int	c;
121{
122	static int escstate;
123
124	if (escstate == 1) {
125		/* ESC seen, look for [ or O */
126		if (c == '[' || c == 'O')
127			escstate++;
128		else
129			escstate = 0; /* re-init state machine */
130		return (0);
131	} else if (escstate == 2) {
132		escstate = 0;
133		/*
134		 * If a valid cursor key has been found, translate
135		 * into an emacs-style control key, and fall through.
136		 * Otherwise, drop off.
137		 */
138		switch (c) {
139		case 'A':	/* up */
140			c = CTRL('p');
141			break;
142		case 'B':	/* down */
143			c = CTRL('n');
144			break;
145		case 'C':	/* right */
146			c = CTRL('f');
147			break;
148		case 'D':	/* left */
149			c = CTRL('b');
150			break;
151		default:
152			return (0);
153		}
154	}
155
156	switch (c) {
157	    case CTRL('['):
158		escstate = 1;
159		break;
160	    case CTRL('b'):
161		/* back up one character */
162		if (db_lc > db_lbuf_start) {
163		    cnputc(BACKUP);
164		    db_lc--;
165		}
166		break;
167	    case CTRL('f'):
168		/* forward one character */
169		if (db_lc < db_le) {
170		    cnputc(*db_lc);
171		    db_lc++;
172		}
173		break;
174	    case CTRL('a'):
175		/* beginning of line */
176		while (db_lc > db_lbuf_start) {
177		    cnputc(BACKUP);
178		    db_lc--;
179		}
180		break;
181	    case CTRL('e'):
182		/* end of line */
183		while (db_lc < db_le) {
184		    cnputc(*db_lc);
185		    db_lc++;
186		}
187		break;
188	    case CTRL('h'):
189	    case 0177:
190		/* erase previous character */
191		if (db_lc > db_lbuf_start)
192		    db_delete(1, DEL_BWD);
193		break;
194	    case CTRL('d'):
195		/* erase next character */
196		if (db_lc < db_le)
197		    db_delete(1, DEL_FWD);
198		break;
199	    case CTRL('u'):
200	    case CTRL('c'):
201		/* kill entire line: */
202		/* at first, delete to beginning of line */
203		if (db_lc > db_lbuf_start)
204		    db_delete(db_lc - db_lbuf_start, DEL_BWD);
205		/* FALLTHROUGH */
206	    case CTRL('k'):
207		/* delete to end of line */
208		if (db_lc < db_le)
209		    db_delete(db_le - db_lc, DEL_FWD);
210		break;
211	    case CTRL('t'):
212		/* twiddle last 2 characters */
213		if (db_lc >= db_lbuf_start + 2) {
214		    c = db_lc[-2];
215		    db_lc[-2] = db_lc[-1];
216		    db_lc[-1] = c;
217		    cnputc(BACKUP);
218		    cnputc(BACKUP);
219		    cnputc(db_lc[-2]);
220		    cnputc(db_lc[-1]);
221		}
222		break;
223	    case CTRL('w'):
224		/* erase previous word */
225		for (; db_lc > db_lbuf_start;) {
226		    if (*(db_lc - 1) != ' ')
227			break;
228		    db_delete(1, DEL_BWD);
229		}
230		for (; db_lc > db_lbuf_start;) {
231		    if (*(db_lc - 1) == ' ')
232			break;
233		    db_delete(1, DEL_BWD);
234		}
235		break;
236	    case CTRL('r'):
237		db_putstring("^R\n", 3);
238	    redraw:
239		if (db_le > db_lbuf_start) {
240		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
241		    db_putnchars(BACKUP, db_le - db_lc);
242		}
243		break;
244	    case CTRL('p'):
245		/* Make previous history line the active one. */
246		if (db_lhistcur >= 0) {
247		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
248			  db_lbuf_start, db_lhistlsize);
249		    db_lhistcur--;
250		    goto hist_redraw;
251		}
252		break;
253	    case CTRL('n'):
254		/* Make next history line the active one. */
255		if (db_lhistcur < db_lhistidx - 1) {
256		    db_lhistcur += 2;
257		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
258			  db_lbuf_start, db_lhistlsize);
259		} else {
260		    /*
261		     * ^N through tail of history, reset the
262		     * buffer to zero length.
263		     */
264		    *db_lbuf_start = '\0';
265		    db_lhistcur = db_lhistidx;
266		}
267
268	    hist_redraw:
269		db_putnchars(BACKUP, db_lc - db_lbuf_start);
270		db_putnchars(BLANK, db_le - db_lbuf_start);
271		db_putnchars(BACKUP, db_le - db_lbuf_start);
272		db_le = strchr(db_lbuf_start, '\0');
273		if (db_le[-1] == '\r' || db_le[-1] == '\n')
274		    *--db_le = '\0';
275		db_lc = db_le;
276		goto redraw;
277
278	    case -1:
279		/*
280		 * eek! the console returned eof.
281		 * probably that means we HAVE no console.. we should try bail
282		 * XXX
283		 */
284		c = '\r';
285	    case '\n':
286		/* FALLTHROUGH */
287	    case '\r':
288		*db_le++ = c;
289		return (1);
290	    default:
291		if (db_le == db_lbuf_end) {
292		    cnputc('\007');
293		}
294		else if (c >= ' ' && c <= '~') {
295		    char *p;
296
297		    for (p = db_le; p > db_lc; p--)
298			*p = *(p-1);
299		    *db_lc++ = c;
300		    db_le++;
301		    cnputc(c);
302		    db_putstring(db_lc, db_le - db_lc);
303		    db_putnchars(BACKUP, db_le - db_lc);
304		}
305		break;
306	}
307	return (0);
308}
309
310static int
311cnmaygetc()
312{
313	return (-1);
314}
315
316int
317db_readline(lstart, lsize)
318	char *	lstart;
319	int	lsize;
320{
321
322	if (lsize < 2)
323		return (0);
324	if (lsize != db_lhistlsize) {
325		/*
326		 * (Re)initialize input line history.  Throw away any
327		 * existing history.
328		 */
329		db_lhist_nlines = sizeof(db_lhistory) / lsize;
330		db_lhistlsize = lsize;
331		db_lhistidx = -1;
332	}
333	db_lhistcur = db_lhistidx;
334
335	db_force_whitespace();	/* synch output position */
336
337	db_lbuf_start = lstart;
338	db_lbuf_end   = lstart + lsize - 2;	/* Will append NL and NUL. */
339	db_lc = lstart;
340	db_le = lstart;
341
342	while (!db_inputchar(cngetc()))
343	    continue;
344
345	db_capture_write(lstart, db_le - db_lbuf_start);
346	db_printf("\n");	/* synch output position */
347	*db_le = 0;
348
349	if (db_le - db_lbuf_start > 1) {
350	    /* Maintain input line history for non-empty lines. */
351	    if (++db_lhistidx == db_lhist_nlines) {
352		/* Rotate history. */
353		bcopy(db_lhistory + db_lhistlsize, db_lhistory,
354		      db_lhistlsize * (db_lhist_nlines - 1));
355		db_lhistidx--;
356	    }
357	    bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
358		  db_lhistlsize);
359	}
360
361	return (db_le - db_lbuf_start);
362}
363
364void
365db_check_interrupt(void)
366{
367	int	c;
368
369	c = cnmaygetc();
370	switch (c) {
371	    case -1:		/* no character */
372		return;
373
374	    case CTRL('c'):
375		db_error((char *)0);
376		/*NOTREACHED*/
377
378	    case CTRL('s'):
379		do {
380		    c = cnmaygetc();
381		    if (c == CTRL('c'))
382			db_error((char *)0);
383		} while (c != CTRL('q'));
384		break;
385
386	    default:
387		/* drop on floor */
388		break;
389	}
390}
391