1/*	$NetBSD: db_input.c,v 1.25 2010/08/31 07:12:55 enami 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 1.25 2010/08/31 07:12:55 enami 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#include <sys/cpu.h>
42
43#include <ddb/ddb.h>
44
45#include <dev/cons.h>
46
47#ifndef DDB_HISTORY_SIZE
48#define DDB_HISTORY_SIZE 0
49#endif /* DDB_HISTORY_SIZE */
50
51/*
52 * Character input and editing.
53 */
54
55/*
56 * We don't track output position while editing input,
57 * since input always ends with a new-line.  We just
58 * reset the line position at the end.
59 */
60static char    *db_lbuf_start;	/* start of input line buffer */
61static char    *db_lbuf_end;	/* end of input line buffer */
62static char    *db_lc;		/* current character */
63static char    *db_le;		/* one past last character */
64#if DDB_HISTORY_SIZE != 0
65static char	db_history[DDB_HISTORY_SIZE];	/* start of history buffer */
66static char    *db_history_curr = db_history;	/* start of current line */
67static char    *db_history_last = db_history;	/* start of last line */
68static char    *db_history_prev = (char *) 0;	/* start of previous line */
69#endif
70
71
72#define	CTRL(c)		((c) & 0x1f)
73#define	isspace(c)	((c) == ' ' || (c) == '\t')
74#define	BLANK		' '
75#define	BACKUP		'\b'
76
77static int	cnmaygetc(void);
78static void	db_putstring(const char *, int);
79static void	db_putnchars(int, int);
80static void	db_delete(int, int);
81static void	db_delete_line(void);
82static int	db_inputchar(int);
83
84static void
85db_putstring(const char *s, int count)
86{
87
88	while (--count >= 0)
89		cnputc(*s++);
90}
91
92static void
93db_putnchars(int c, int count)
94{
95
96	while (--count >= 0)
97		cnputc(c);
98}
99
100/*
101 * Delete N characters, forward or backward
102 */
103#define	DEL_FWD		0
104#define	DEL_BWD		1
105static void
106db_delete(int n, int bwd)
107{
108	char *p;
109
110	if (bwd) {
111		db_lc -= n;
112		db_putnchars(BACKUP, n);
113	}
114	for (p = db_lc; p < db_le-n; p++) {
115		*p = *(p+n);
116		cnputc(*p);
117	}
118	db_putnchars(BLANK, n);
119	db_putnchars(BACKUP, db_le - db_lc);
120	db_le -= n;
121}
122
123static void
124db_delete_line(void)
125{
126
127	db_delete(db_le - db_lc, DEL_FWD);
128	db_delete(db_lc - db_lbuf_start, DEL_BWD);
129	db_le = db_lc = db_lbuf_start;
130}
131
132#if DDB_HISTORY_SIZE != 0
133
134#define INC_DB_CURR() do {						\
135	++db_history_curr;						\
136	if (db_history_curr > db_history + DDB_HISTORY_SIZE - 1)	\
137		db_history_curr = db_history;				\
138    } while (0)
139#define DEC_DB_CURR() do {						\
140	--db_history_curr;						\
141	if (db_history_curr < db_history)				\
142		db_history_curr = db_history + DDB_HISTORY_SIZE - 1;	\
143    } while (0)
144
145static inline void
146db_hist_put(int c)
147{
148	KASSERT(&db_history[0]  <= db_history_last);
149	KASSERT(db_history_last <= &db_history[DDB_HISTORY_SIZE-1]);
150
151	*db_history_last++ = c;
152
153	if (db_history_last > &db_history[DDB_HISTORY_SIZE-1])
154	    db_history_last = db_history;
155}
156#endif
157
158
159/* returns true at end-of-line */
160static int
161db_inputchar(int c)
162{
163	switch (c) {
164	case CTRL('b'):
165		/* back up one character */
166		if (db_lc > db_lbuf_start) {
167			cnputc(BACKUP);
168			db_lc--;
169		}
170		break;
171	case CTRL('f'):
172		/* forward one character */
173		if (db_lc < db_le) {
174			cnputc(*db_lc);
175			db_lc++;
176		}
177		break;
178	case CTRL('a'):
179		/* beginning of line */
180		while (db_lc > db_lbuf_start) {
181			cnputc(BACKUP);
182			db_lc--;
183		}
184		break;
185	case CTRL('e'):
186		/* end of line */
187		while (db_lc < db_le) {
188			cnputc(*db_lc);
189			db_lc++;
190		}
191		break;
192	case CTRL('h'):
193	case 0177:
194		/* erase previous character */
195		if (db_lc > db_lbuf_start)
196			db_delete(1, DEL_BWD);
197		break;
198	case CTRL('d'):
199		/* erase next character */
200		if (db_lc < db_le)
201			db_delete(1, DEL_FWD);
202		break;
203	case CTRL('k'):
204		/* delete to end of line */
205		if (db_lc < db_le)
206			db_delete(db_le - db_lc, DEL_FWD);
207		break;
208	case CTRL('u'):
209		/* delete line */
210		db_delete_line();
211		break;
212	case CTRL('t'):
213		/* twiddle last 2 characters */
214		if (db_lc >= db_lbuf_start + 1) {
215			if (db_lc < db_le) {
216				c = db_lc[-1];
217				db_lc[-1] = db_lc[0];
218				db_lc[0] = c;
219				cnputc(BACKUP);
220				cnputc(db_lc[-1]);
221				cnputc(db_lc[0]);
222				db_lc++;
223			} else if (db_lc >= db_lbuf_start + 2) {
224				c = db_lc[-2];
225				db_lc[-2] = db_lc[-1];
226				db_lc[-1] = c;
227				cnputc(BACKUP);
228				cnputc(BACKUP);
229				cnputc(db_lc[-2]);
230				cnputc(db_lc[-1]);
231			}
232		}
233		break;
234#if DDB_HISTORY_SIZE != 0
235	case CTRL('p'):
236		DEC_DB_CURR();
237		while (db_history_curr != db_history_last) {
238			DEC_DB_CURR();
239			if (*db_history_curr == '\0')
240				break;
241		}
242		db_delete_line();
243		if (db_history_curr == db_history_last) {
244			INC_DB_CURR();
245			db_le = db_lc = db_lbuf_start;
246		} else {
247			char *p;
248			INC_DB_CURR();
249			for (p = db_history_curr, db_le = db_lbuf_start;
250			     *p; ) {
251				*db_le++ = *p++;
252				if (p >= db_history + DDB_HISTORY_SIZE) {
253					p = db_history;
254				}
255			}
256			db_lc = db_le;
257		}
258		db_putstring(db_lbuf_start, db_le - db_lbuf_start);
259		break;
260	case CTRL('n'):
261		while (db_history_curr != db_history_last) {
262			if (*db_history_curr == '\0')
263				break;
264			INC_DB_CURR();
265		}
266		if (db_history_curr != db_history_last) {
267			INC_DB_CURR();
268			db_delete_line();
269			if (db_history_curr != db_history_last) {
270				char *p;
271				for (p = db_history_curr,
272				     db_le = db_lbuf_start; *p;) {
273					*db_le++ = *p++;
274					if (p >= db_history + DDB_HISTORY_SIZE) {
275						p = db_history;
276					}
277				}
278				db_lc = db_le;
279			}
280			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
281		}
282		break;
283#endif
284	case CTRL('r'):
285		db_putstring("^R\n", 3);
286		if (db_le > db_lbuf_start) {
287			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
288			db_putnchars(BACKUP, db_le - db_lc);
289		}
290		break;
291	case '\n':
292	case '\r':
293#if DDB_HISTORY_SIZE != 0
294		/* Check if it same than previous line */
295		if (db_history_curr == db_history_prev) {
296			char *pp, *pc;
297
298			/* Is it unmodified */
299			for (pp = db_history_prev, pc = db_lbuf_start;
300			     pc != db_le && *pp; pp++, pc++) {
301				if (*pp != *pc)
302					break;
303				if (++pp >= db_history + DDB_HISTORY_SIZE) {
304					pp = db_history;
305				}
306				if (++pc >= db_history + DDB_HISTORY_SIZE) {
307					pc = db_history;
308				}
309			}
310			if (!*pp && pc == db_le) {
311				/* Repeted previous line, not saved */
312				db_history_curr = db_history_last;
313				*db_le++ = c;
314				return (true);
315			}
316		}
317		if (db_le != db_lbuf_start) {
318			char *p;
319
320			db_history_prev = db_history_last;
321
322			for (p = db_lbuf_start; p != db_le; ) {
323				db_hist_put(*p++);
324			}
325			db_hist_put(0);
326		}
327		db_history_curr = db_history_last;
328#endif
329		*db_le++ = c;
330		return (1);
331	default:
332		if (db_le == db_lbuf_end) {
333			cnputc('\007');
334		}
335		else if (c >= ' ' && c <= '~') {
336			char *p;
337
338			for (p = db_le; p > db_lc; p--)
339				*p = *(p-1);
340			*db_lc++ = c;
341			db_le++;
342			cnputc(c);
343			db_putstring(db_lc, db_le - db_lc);
344			db_putnchars(BACKUP, db_le - db_lc);
345		}
346		break;
347	}
348	return (0);
349}
350
351int
352db_readline(char *lstart, int lsize)
353{
354
355# ifdef MULTIPROCESSOR
356	db_printf("db{%ld}> ", (long)cpu_number());
357# else
358	db_printf("db> ");
359# endif
360	db_force_whitespace();	/* synch output position */
361
362	db_lbuf_start = lstart;
363	db_lbuf_end   = lstart + lsize;
364	db_lc = lstart;
365	db_le = lstart;
366
367	while (!db_inputchar(cngetc()))
368		continue;
369
370	db_putchar('\n');	/* synch output position */
371
372	*db_le = 0;
373	return (db_le - db_lbuf_start);
374}
375
376void
377db_check_interrupt(void)
378{
379	int	c;
380
381	c = cnmaygetc();
382	switch (c) {
383	case -1:		/* no character */
384		return;
385
386	case CTRL('c'):
387		db_error((char *)0);
388		/*NOTREACHED*/
389
390	case CTRL('s'):
391		do {
392			c = cnmaygetc();
393			if (c == CTRL('c')) {
394				db_error((char *)0);
395				/*NOTREACHED*/
396			}
397		} while (c != CTRL('q'));
398		break;
399
400	default:
401		/* drop on floor */
402		break;
403	}
404}
405
406static int
407cnmaygetc(void)
408{
409
410	return (-1);
411}
412