db_input.c revision 1.27 
1/*	$NetBSD: db_input.c,v 1.27 2019/09/29 02:00:22 uwe Exp $	*/
2
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 "AS IS"
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 *	Author: David B. Golub, Carnegie Mellon University
29 *	Date:	7/90
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: db_input.c,v 1.27 2019/09/29 02:00:22 uwe Exp $");
34
35#ifdef _KERNEL_OPT
36#include "opt_ddbparam.h"
37#endif
38
39#include <sys/param.h>
40#include <sys/proc.h>
41
42#include <ddb/ddb.h>
43
44#include <dev/cons.h>
45
46#ifndef DDB_HISTORY_SIZE
47#define DDB_HISTORY_SIZE 0
48#endif /* DDB_HISTORY_SIZE */
49
50/*
51 * Character input and editing.
52 */
53
54/*
55 * We don't track output position while editing input,
56 * since input always ends with a new-line.  We just
57 * reset the line position at the end.
58 */
59static char    *db_lbuf_start;	/* start of input line buffer */
60static char    *db_lbuf_end;	/* end of input line buffer */
61static char    *db_lc;		/* current character */
62static char    *db_le;		/* one past last character */
63#if DDB_HISTORY_SIZE != 0
64static char	db_history[DDB_HISTORY_SIZE];	/* start of history buffer */
65static char    *db_history_curr = db_history;	/* start of current line */
66static char    *db_history_last = db_history;	/* start of last line */
67static char    *db_history_prev = (char *) 0;	/* start of previous line */
68#endif
69
70
71#define	CTRL(c)		((c) & 0x1f)
72#define	isspace(c)	((c) == ' ' || (c) == '\t')
73#define	BLANK		' '
74#define	BACKUP		'\b'
75
76static int	cnmaygetc(void);
77static void	db_putstring(const char *, int);
78static void	db_putnchars(int, int);
79static void	db_delete(int, int);
80static void	db_delete_line(void);
81static int	db_inputchar(int);
82
83static void
84db_putstring(const char *s, int count)
85{
86
87	while (--count >= 0)
88		cnputc(*s++);
89}
90
91static void
92db_putnchars(int c, int count)
93{
94
95	while (--count >= 0)
96		cnputc(c);
97}
98
99/*
100 * Delete N characters, forward or backward
101 */
102#define	DEL_FWD		0
103#define	DEL_BWD		1
104static void
105db_delete(int n, int bwd)
106{
107	char *p;
108
109	if (bwd) {
110		db_lc -= n;
111		db_putnchars(BACKUP, n);
112	}
113	for (p = db_lc; p < db_le-n; p++) {
114		*p = *(p+n);
115		cnputc(*p);
116	}
117	db_putnchars(BLANK, n);
118	db_putnchars(BACKUP, db_le - db_lc);
119	db_le -= n;
120}
121
122static void
123db_delete_line(void)
124{
125
126	db_delete(db_le - db_lc, DEL_FWD);
127	db_delete(db_lc - db_lbuf_start, DEL_BWD);
128	db_le = db_lc = db_lbuf_start;
129}
130
131#if DDB_HISTORY_SIZE != 0
132
133#define INC_DB_CURR() do {						\
134	++db_history_curr;						\
135	if (db_history_curr > db_history + DDB_HISTORY_SIZE - 1)	\
136		db_history_curr = db_history;				\
137    } while (0)
138#define DEC_DB_CURR() do {						\
139	--db_history_curr;						\
140	if (db_history_curr < db_history)				\
141		db_history_curr = db_history + DDB_HISTORY_SIZE - 1;	\
142    } while (0)
143
144static inline void
145db_hist_put(int c)
146{
147	KASSERT(&db_history[0]  <= db_history_last);
148	KASSERT(db_history_last <= &db_history[DDB_HISTORY_SIZE-1]);
149
150	*db_history_last++ = c;
151
152	if (db_history_last > &db_history[DDB_HISTORY_SIZE-1])
153	    db_history_last = db_history;
154}
155#endif
156
157
158/* returns true at end-of-line */
159static int
160db_inputchar(int c)
161{
162	switch (c) {
163	case CTRL('b'):
164		/* back up one character */
165		if (db_lc > db_lbuf_start) {
166			cnputc(BACKUP);
167			db_lc--;
168		}
169		break;
170	case CTRL('f'):
171		/* forward one character */
172		if (db_lc < db_le) {
173			cnputc(*db_lc);
174			db_lc++;
175		}
176		break;
177	case CTRL('a'):
178		/* beginning of line */
179		while (db_lc > db_lbuf_start) {
180			cnputc(BACKUP);
181			db_lc--;
182		}
183		break;
184	case CTRL('e'):
185		/* end of line */
186		while (db_lc < db_le) {
187			cnputc(*db_lc);
188			db_lc++;
189		}
190		break;
191	case CTRL('h'):
192	case 0177:
193		/* erase previous character */
194		if (db_lc > db_lbuf_start)
195			db_delete(1, DEL_BWD);
196		break;
197	case CTRL('d'):
198		/* erase next character */
199		if (db_lc < db_le)
200			db_delete(1, DEL_FWD);
201		break;
202	case CTRL('k'):
203		/* delete to end of line */
204		if (db_lc < db_le)
205			db_delete(db_le - db_lc, DEL_FWD);
206		break;
207	case CTRL('u'):
208		/* delete line */
209		db_delete_line();
210		break;
211	case CTRL('t'):
212		/* twiddle last 2 characters */
213		if (db_lc >= db_lbuf_start + 1) {
214			if (db_lc < db_le) {
215				c = db_lc[-1];
216				db_lc[-1] = db_lc[0];
217				db_lc[0] = c;
218				cnputc(BACKUP);
219				cnputc(db_lc[-1]);
220				cnputc(db_lc[0]);
221				db_lc++;
222			} else if (db_lc >= db_lbuf_start + 2) {
223				c = db_lc[-2];
224				db_lc[-2] = db_lc[-1];
225				db_lc[-1] = c;
226				cnputc(BACKUP);
227				cnputc(BACKUP);
228				cnputc(db_lc[-2]);
229				cnputc(db_lc[-1]);
230			}
231		}
232		break;
233#if DDB_HISTORY_SIZE != 0
234	case CTRL('p'):
235		DEC_DB_CURR();
236		while (db_history_curr != db_history_last) {
237			DEC_DB_CURR();
238			if (*db_history_curr == '\0')
239				break;
240		}
241		db_delete_line();
242		if (db_history_curr == db_history_last) {
243			INC_DB_CURR();
244			db_le = db_lc = db_lbuf_start;
245		} else {
246			char *p;
247			INC_DB_CURR();
248			for (p = db_history_curr, db_le = db_lbuf_start;
249			     *p; ) {
250				*db_le++ = *p++;
251				if (p >= db_history + DDB_HISTORY_SIZE) {
252					p = db_history;
253				}
254			}
255			db_lc = db_le;
256		}
257		db_putstring(db_lbuf_start, db_le - db_lbuf_start);
258		break;
259	case CTRL('n'):
260		while (db_history_curr != db_history_last) {
261			if (*db_history_curr == '\0')
262				break;
263			INC_DB_CURR();
264		}
265		if (db_history_curr != db_history_last) {
266			INC_DB_CURR();
267			db_delete_line();
268			if (db_history_curr != db_history_last) {
269				char *p;
270				for (p = db_history_curr,
271				     db_le = db_lbuf_start; *p;) {
272					*db_le++ = *p++;
273					if (p >= db_history + DDB_HISTORY_SIZE) {
274						p = db_history;
275					}
276				}
277				db_lc = db_le;
278			}
279			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
280		}
281		break;
282#endif
283	case CTRL('r'):
284		db_putstring("^R\n", 3);
285		if (db_le > db_lbuf_start) {
286			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
287			db_putnchars(BACKUP, db_le - db_lc);
288		}
289		break;
290	case '\n':
291	case '\r':
292#if DDB_HISTORY_SIZE != 0
293		/* Check if it same than previous line */
294		if (db_history_curr == db_history_prev) {
295			char *pp, *pc;
296
297			/* Is it unmodified */
298			for (pp = db_history_prev, pc = db_lbuf_start;
299			     pc != db_le && *pp; pp++, pc++) {
300				if (*pp != *pc)
301					break;
302				if (++pp >= db_history + DDB_HISTORY_SIZE) {
303					pp = db_history;
304				}
305				if (++pc >= db_history + DDB_HISTORY_SIZE) {
306					pc = db_history;
307				}
308			}
309			if (!*pp && pc == db_le) {
310				/* Repeted previous line, not saved */
311				db_history_curr = db_history_last;
312				*db_le++ = c;
313				return (true);
314			}
315		}
316		if (db_le != db_lbuf_start) {
317			char *p;
318
319			db_history_prev = db_history_last;
320
321			for (p = db_lbuf_start; p != db_le; ) {
322				db_hist_put(*p++);
323			}
324			db_hist_put(0);
325		}
326		db_history_curr = db_history_last;
327#endif
328		*db_le++ = c;
329		return (1);
330	default:
331		if (db_le == db_lbuf_end) {
332			cnputc('\007');
333		}
334		else if (c >= ' ' && c <= '~') {
335			char *p;
336
337			for (p = db_le; p > db_lc; p--)
338				*p = *(p-1);
339			*db_lc++ = c;
340			db_le++;
341			cnputc(c);
342			db_putstring(db_lc, db_le - db_lc);
343			db_putnchars(BACKUP, db_le - db_lc);
344		}
345		break;
346	}
347	return (0);
348}
349
350int
351db_readline(char *lstart, int lsize)
352{
353
354	db_force_whitespace();	/* synch output position */
355
356	db_lbuf_start = lstart;
357	db_lbuf_end   = lstart + lsize;
358	db_lc = lstart;
359	db_le = lstart;
360
361	while (!db_inputchar(cngetc()))
362		continue;
363
364	db_putchar('\n');	/* synch output position */
365
366	*db_le = 0;
367	return (db_le - db_lbuf_start);
368}
369
370void
371db_check_interrupt(void)
372{
373	int	c;
374
375	c = cnmaygetc();
376	switch (c) {
377	case -1:		/* no character */
378		return;
379
380	case CTRL('c'):
381		db_error((char *)0);
382		/*NOTREACHED*/
383
384	case CTRL('s'):
385		do {
386			c = cnmaygetc();
387			if (c == CTRL('c')) {
388				db_error((char *)0);
389				/*NOTREACHED*/
390			}
391		} while (c != CTRL('q'));
392		break;
393
394	default:
395		/* drop on floor */
396		break;
397	}
398}
399
400static int
401cnmaygetc(void)
402{
403
404	return (-1);
405}
406