xref: /netbsd-src/sys/ddb/db_command.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: db_command.c,v 1.76 2004/04/27 04:03:28 atatat 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 
29 /*
30  * Command dispatcher.
31  */
32 
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: db_command.c,v 1.76 2004/04/27 04:03:28 atatat Exp $");
35 
36 #include "opt_ddb.h"
37 #include "opt_kgdb.h"
38 #include "opt_inet.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/reboot.h>
43 #include <sys/device.h>
44 #include <sys/malloc.h>
45 #include <sys/namei.h>
46 #include <sys/pool.h>
47 #include <sys/proc.h>
48 #include <sys/vnode.h>
49 
50 #include <machine/db_machdep.h>		/* type definitions */
51 
52 #if defined(_KERNEL_OPT)
53 #include "opt_multiprocessor.h"
54 #endif
55 #ifdef MULTIPROCESSOR
56 #include <machine/cpu.h>
57 #endif
58 
59 #include <ddb/db_lex.h>
60 #include <ddb/db_output.h>
61 #include <ddb/db_command.h>
62 #include <ddb/db_break.h>
63 #include <ddb/db_watch.h>
64 #include <ddb/db_run.h>
65 #include <ddb/db_variables.h>
66 #include <ddb/db_interface.h>
67 #include <ddb/db_sym.h>
68 #include <ddb/db_extern.h>
69 
70 #include <uvm/uvm_extern.h>
71 #include <uvm/uvm_ddb.h>
72 
73 #include "arp.h"
74 
75 /*
76  * Results of command search.
77  */
78 #define	CMD_UNIQUE	0
79 #define	CMD_FOUND	1
80 #define	CMD_NONE	2
81 #define	CMD_AMBIGUOUS	3
82 #define	CMD_HELP	4
83 
84 /*
85  * Exported global variables
86  */
87 boolean_t	db_cmd_loop_done;
88 label_t		*db_recover;
89 db_addr_t	db_dot;
90 db_addr_t	db_last_addr;
91 db_addr_t	db_prev;
92 db_addr_t	db_next;
93 
94 /*
95  * if 'ed' style: 'dot' is set at start of last item printed,
96  * and '+' points to next line.
97  * Otherwise: 'dot' points to next item, '..' points to last.
98  */
99 static boolean_t db_ed_style = TRUE;
100 
101 static void	db_buf_print_cmd(db_expr_t, int, db_expr_t, char *);
102 static void	db_cmd_list(const struct db_command *);
103 static int	db_cmd_search(const char *, const struct db_command *,
104 		    const struct db_command **);
105 static void	db_command(const struct db_command **,
106 		    const struct db_command *);
107 static void	db_event_print_cmd(db_expr_t, int, db_expr_t, char *);
108 static void	db_fncall(db_expr_t, int, db_expr_t, char *);
109 static void	db_malloc_print_cmd(db_expr_t, int, db_expr_t, char *);
110 static void	db_map_print_cmd(db_expr_t, int, db_expr_t, char *);
111 static void	db_namecache_print_cmd(db_expr_t, int, db_expr_t, char *);
112 static void	db_object_print_cmd(db_expr_t, int, db_expr_t, char *);
113 static void	db_page_print_cmd(db_expr_t, int, db_expr_t, char *);
114 static void	db_pool_print_cmd(db_expr_t, int, db_expr_t, char *);
115 static void	db_reboot_cmd(db_expr_t, int, db_expr_t, char *);
116 static void	db_sifting_cmd(db_expr_t, int, db_expr_t, char *);
117 static void	db_stack_trace_cmd(db_expr_t, int, db_expr_t, char *);
118 static void	db_sync_cmd(db_expr_t, int, db_expr_t, char *);
119 static void	db_uvmexp_print_cmd(db_expr_t, int, db_expr_t, char *);
120 static void	db_vnode_print_cmd(db_expr_t, int, db_expr_t, char *);
121 static void	db_mount_print_cmd(db_expr_t, int, db_expr_t, char *);
122 
123 /*
124  * 'show' commands
125  */
126 
127 static const struct db_command db_show_all_cmds[] = {
128 	{ "callout",	db_show_callout,	0, NULL },
129 	{ "procs",	db_show_all_procs,	0, NULL },
130 	{ NULL, 	NULL, 			0, NULL }
131 };
132 
133 static const struct db_command db_show_cmds[] = {
134 	{ "all",	NULL,			0,	db_show_all_cmds },
135 #if defined(INET) && (NARP > 0)
136 	{ "arptab",	db_show_arptab,		0,	NULL },
137 #endif
138 	{ "breaks",	db_listbreak_cmd, 	0,	NULL },
139 	{ "buf",	db_buf_print_cmd,	0,	NULL },
140 	{ "event",	db_event_print_cmd,	0,	NULL },
141 	{ "malloc",	db_malloc_print_cmd,	0,	NULL },
142 	{ "map",	db_map_print_cmd,	0,	NULL },
143 	{ "mount",	db_mount_print_cmd,	0,	NULL },
144 	{ "ncache",	db_namecache_print_cmd,	0,	NULL },
145 	{ "object",	db_object_print_cmd,	0,	NULL },
146 	{ "page",	db_page_print_cmd,	0,	NULL },
147 	{ "pool",	db_pool_print_cmd,	0,	NULL },
148 	{ "registers",	db_show_regs,		0,	NULL },
149 	{ "sched_qs",	db_show_sched_qs,	0,	NULL },
150 	{ "uvmexp",	db_uvmexp_print_cmd,	0,	NULL },
151 	{ "vnode",	db_vnode_print_cmd,	0,	NULL },
152 	{ "watches",	db_listwatch_cmd, 	0,	NULL },
153 	{ NULL,		NULL,			0,	NULL }
154 };
155 
156 static const struct db_command db_command_table[] = {
157 	{ "b",		db_breakpoint_cmd,	0,		NULL },
158 	{ "break",	db_breakpoint_cmd,	0,		NULL },
159 	{ "bt",		db_stack_trace_cmd,	0,		NULL },
160 	{ "c",		db_continue_cmd,	0,		NULL },
161 	{ "call",	db_fncall,		CS_OWN,		NULL },
162 	{ "callout",	db_show_callout,	0,		NULL },
163 	{ "continue",	db_continue_cmd,	0,		NULL },
164 	{ "d",		db_delete_cmd,		0,		NULL },
165 	{ "delete",	db_delete_cmd,		0,		NULL },
166 	{ "dmesg",	db_dmesg,		0,		NULL },
167 	{ "dwatch",	db_deletewatch_cmd,	0,		NULL },
168 	{ "examine",	db_examine_cmd,		CS_SET_DOT, 	NULL },
169 	{ "kill",	db_kill_proc,		CS_OWN,		NULL },
170 #ifdef KGDB
171 	{ "kgdb",	db_kgdb_cmd,		0,		NULL },
172 #endif
173 #ifdef DB_MACHINE_COMMANDS
174 	{ "machine",	NULL,			0, db_machine_command_table },
175 #endif
176 	{ "match",	db_trace_until_matching_cmd,0,		NULL },
177 	{ "next",	db_trace_until_matching_cmd,0,		NULL },
178 	{ "p",		db_print_cmd,		0,		NULL },
179 	{ "print",	db_print_cmd,		0,		NULL },
180 	{ "ps",		db_show_all_procs,	0,		NULL },
181 	{ "reboot",	db_reboot_cmd,		CS_OWN,		NULL },
182 	{ "s",		db_single_step_cmd,	0,		NULL },
183 	{ "search",	db_search_cmd,		CS_OWN|CS_SET_DOT, NULL },
184 	{ "set",	db_set_cmd,		CS_OWN,		NULL },
185 	{ "show",	NULL,			0,		db_show_cmds },
186 	{ "sifting",	db_sifting_cmd,		CS_OWN,		NULL },
187 	{ "step",	db_single_step_cmd,	0,		NULL },
188 	{ "sync",	db_sync_cmd,		CS_OWN,		NULL },
189 	{ "trace",	db_stack_trace_cmd,	0,		NULL },
190 	{ "until",	db_trace_until_call_cmd,0,		NULL },
191 	{ "w",		db_write_cmd,		CS_MORE|CS_SET_DOT, NULL },
192 	{ "watch",	db_watchpoint_cmd,	CS_MORE,	NULL },
193 	{ "write",	db_write_cmd,		CS_MORE|CS_SET_DOT, NULL },
194 	{ "x",		db_examine_cmd,		CS_SET_DOT, 	NULL },
195 	{ NULL, 	NULL,			0,		NULL }
196 };
197 
198 static const struct db_command	*db_last_command = NULL;
199 
200 /*
201  * Utility routine - discard tokens through end-of-line.
202  */
203 void
204 db_skip_to_eol(void)
205 {
206 	int t;
207 
208 	do {
209 		t = db_read_token();
210 	} while (t != tEOL);
211 }
212 
213 void
214 db_error(s)
215 	char *s;
216 {
217 
218 	if (s)
219 		db_printf("%s", s);
220 	db_flush_lex();
221 	longjmp(db_recover);
222 }
223 
224 void
225 db_command_loop(void)
226 {
227 	label_t	db_jmpbuf;
228 	label_t	*savejmp;
229 
230 	/*
231 	 * Initialize 'prev' and 'next' to dot.
232 	 */
233 	db_prev = db_dot;
234 	db_next = db_dot;
235 
236 	db_cmd_loop_done = 0;
237 
238 	savejmp = db_recover;
239 	db_recover = &db_jmpbuf;
240 	(void) setjmp(&db_jmpbuf);
241 
242 	while (!db_cmd_loop_done) {
243 		if (db_print_position() != 0)
244 			db_printf("\n");
245 		db_output_line = 0;
246 
247 
248 #ifdef MULTIPROCESSOR
249 		db_printf("db{%ld}> ", (long)cpu_number());
250 #else
251 		db_printf("db> ");
252 #endif
253 		(void) db_read_line();
254 
255 		db_command(&db_last_command, db_command_table);
256 	}
257 
258 	db_recover = savejmp;
259 }
260 
261 /*
262  * Search for command prefix.
263  */
264 static int
265 db_cmd_search(const char *name, const struct db_command *table,
266     const struct db_command **cmdp)
267 {
268 	const struct db_command	*cmd;
269 	int			result = CMD_NONE;
270 
271 	for (cmd = table; cmd->name != 0; cmd++) {
272 		const char *lp;
273 		const char *rp;
274 		int  c;
275 
276 		lp = name;
277 		rp = cmd->name;
278 		while ((c = *lp) == *rp) {
279 			if (c == 0) {
280 				/* complete match */
281 				*cmdp = cmd;
282 				return (CMD_UNIQUE);
283 			}
284 			lp++;
285 			rp++;
286 		}
287 		if (c == 0) {
288 			/* end of name, not end of command -
289 			   partial match */
290 			if (result == CMD_FOUND) {
291 				result = CMD_AMBIGUOUS;
292 				/* but keep looking for a full match -
293 				   this lets us match single letters */
294 			} else {
295 				*cmdp = cmd;
296 				result = CMD_FOUND;
297 			}
298 		}
299 	}
300 	if (result == CMD_NONE) {
301 		/* check for 'help' */
302 		if (name[0] == 'h' && name[1] == 'e'
303 		    && name[2] == 'l' && name[3] == 'p')
304 			result = CMD_HELP;
305 	}
306 	return (result);
307 }
308 
309 static void
310 db_cmd_list(const struct db_command *table)
311 {
312 	int	 i, j, w, columns, lines, width=0, numcmds;
313 	const char	*p;
314 
315 	for (numcmds = 0; table[numcmds].name != NULL; numcmds++) {
316 		w = strlen(table[numcmds].name);
317 		if (w > width)
318 			width = w;
319 	}
320 	width = DB_NEXT_TAB(width);
321 
322 	columns = db_max_width / width;
323 	if (columns == 0)
324 		columns = 1;
325 	lines = (numcmds + columns - 1) / columns;
326 	for (i = 0; i < lines; i++) {
327 		for (j = 0; j < columns; j++) {
328 			p = table[j * lines + i].name;
329 			if (p)
330 				db_printf("%s", p);
331 			if (j * lines + i + lines >= numcmds) {
332 				db_putchar('\n');
333 				break;
334 			}
335 			w = strlen(p);
336 			while (w < width) {
337 				w = DB_NEXT_TAB(w);
338 				db_putchar('\t');
339 			}
340 		}
341 	}
342 }
343 
344 static void
345 db_command(const struct db_command **last_cmdp,
346     const struct db_command *cmd_table)
347 {
348 	const struct db_command	*cmd;
349 	int		t;
350 	char		modif[TOK_STRING_SIZE];
351 	db_expr_t	addr, count;
352 	boolean_t	have_addr = FALSE;
353 	int		result;
354 
355 	static db_expr_t last_count = 0;
356 
357 	t = db_read_token();
358 	if ((t == tEOL) || (t == tCOMMA)) {
359 		/*
360 		 * An empty line repeats last command, at 'next'.
361 		 * Only a count repeats the last command with the new count.
362 		 */
363 		cmd = *last_cmdp;
364 		addr = (db_expr_t)db_next;
365 		if (t == tCOMMA) {
366 			if (!db_expression(&count)) {
367 				db_printf("Count missing\n");
368 				db_flush_lex();
369 				return;
370 			}
371 		} else
372 			count = last_count;
373 		have_addr = FALSE;
374 		modif[0] = '\0';
375 		db_skip_to_eol();
376 	} else if (t == tEXCL) {
377 		db_fncall(0, 0, 0, NULL);
378 		return;
379 	} else if (t != tIDENT) {
380 		db_printf("?\n");
381 		db_flush_lex();
382 		return;
383 	} else {
384 		/*
385 		 * Search for command
386 		 */
387 		while (cmd_table) {
388 			result = db_cmd_search(db_tok_string, cmd_table, &cmd);
389 			switch (result) {
390 			case CMD_NONE:
391 				db_printf("No such command\n");
392 				db_flush_lex();
393 				return;
394 			case CMD_AMBIGUOUS:
395 				db_printf("Ambiguous\n");
396 				db_flush_lex();
397 				return;
398 			case CMD_HELP:
399 				db_cmd_list(cmd_table);
400 				db_flush_lex();
401 				return;
402 			default:
403 				break;
404 			}
405 			if ((cmd_table = cmd->more) != 0) {
406 				t = db_read_token();
407 				if (t != tIDENT) {
408 					db_cmd_list(cmd_table);
409 					db_flush_lex();
410 					return;
411 				}
412 			}
413 		}
414 
415 		if ((cmd->flag & CS_OWN) == 0) {
416 			/*
417 			 * Standard syntax:
418 			 * command [/modifier] [addr] [,count]
419 			 */
420 			t = db_read_token();
421 			if (t == tSLASH) {
422 				t = db_read_token();
423 				if (t != tIDENT) {
424 					db_printf("Bad modifier\n");
425 					db_flush_lex();
426 					return;
427 				}
428 				strlcpy(modif, db_tok_string, sizeof(modif));
429 			} else {
430 				db_unread_token(t);
431 				modif[0] = '\0';
432 			}
433 
434 			if (db_expression(&addr)) {
435 				db_dot = (db_addr_t) addr;
436 				db_last_addr = db_dot;
437 				have_addr = TRUE;
438 			} else {
439 				addr = (db_expr_t) db_dot;
440 				have_addr = FALSE;
441 			}
442 			t = db_read_token();
443 			if (t == tCOMMA) {
444 				if (!db_expression(&count)) {
445 					db_printf("Count missing\n");
446 					db_flush_lex();
447 					return;
448 				}
449 			} else {
450 				db_unread_token(t);
451 				count = -1;
452 			}
453 			if ((cmd->flag & CS_MORE) == 0) {
454 				db_skip_to_eol();
455 			}
456 		}
457 	}
458 	*last_cmdp = cmd;
459 	last_count = count;
460 	if (cmd != 0) {
461 		/*
462 		 * Execute the command.
463 		 */
464 		(*cmd->fcn)(addr, have_addr, count, modif);
465 
466 		if (cmd->flag & CS_SET_DOT) {
467 			/*
468 			 * If command changes dot, set dot to
469 			 * previous address displayed (if 'ed' style).
470 			 */
471 			if (db_ed_style)
472 				db_dot = db_prev;
473 			else
474 				db_dot = db_next;
475 		} else {
476 			/*
477 			 * If command does not change dot,
478 			 * set 'next' location to be the same.
479 			 */
480 			db_next = db_dot;
481 		}
482 	}
483 }
484 
485 /*ARGSUSED*/
486 static void
487 db_map_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
488 {
489 	boolean_t full = FALSE;
490 
491 	if (modif[0] == 'f')
492 		full = TRUE;
493 
494 	if (have_addr == FALSE)
495 		addr = (db_expr_t)(intptr_t) kernel_map;
496 
497 	uvm_map_printit((struct vm_map *)(intptr_t) addr, full, db_printf);
498 }
499 
500 /*ARGSUSED*/
501 static void
502 db_malloc_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
503 {
504 
505 #ifdef MALLOC_DEBUG
506 	if (!have_addr)
507 		addr = 0;
508 
509 	debug_malloc_printit(db_printf, (vaddr_t) addr);
510 #else
511 	db_printf("The kernel is not built with the MALLOC_DEBUG option.\n");
512 #endif /* MALLOC_DEBUG */
513 }
514 
515 /*ARGSUSED*/
516 static void
517 db_object_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
518 {
519 	boolean_t full = FALSE;
520 
521 	if (modif[0] == 'f')
522 		full = TRUE;
523 
524 	uvm_object_printit((struct uvm_object *)(intptr_t) addr, full,
525 	    db_printf);
526 }
527 
528 /*ARGSUSED*/
529 static void
530 db_page_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
531 {
532 	boolean_t full = FALSE;
533 
534 	if (modif[0] == 'f')
535 		full = TRUE;
536 
537 	uvm_page_printit((struct vm_page *)(intptr_t) addr, full, db_printf);
538 }
539 
540 /*ARGSUSED*/
541 static void
542 db_buf_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
543 {
544 	boolean_t full = FALSE;
545 
546 	if (modif[0] == 'f')
547 		full = TRUE;
548 
549 	vfs_buf_print((struct buf *)(intptr_t) addr, full, db_printf);
550 }
551 
552 /*ARGSUSED*/
553 static void
554 db_event_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
555 {
556 	boolean_t full = FALSE;
557 
558 	if (modif[0] == 'f')
559 		full = TRUE;
560 
561 	event_print(full, db_printf);
562 }
563 
564 /*ARGSUSED*/
565 static void
566 db_vnode_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
567 {
568 	boolean_t full = FALSE;
569 
570 	if (modif[0] == 'f')
571 		full = TRUE;
572 
573 	vfs_vnode_print((struct vnode *)(intptr_t) addr, full, db_printf);
574 }
575 
576 static void
577 db_mount_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
578 {
579 	boolean_t full = FALSE;
580 
581 	if (modif[0] == 'f')
582 		full = TRUE;
583 
584 	vfs_mount_print((struct mount *)(intptr_t) addr, full, db_printf);
585 }
586 
587 /*ARGSUSED*/
588 static void
589 db_pool_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
590 {
591 
592 	pool_printit((struct pool *)(intptr_t) addr, modif, db_printf);
593 }
594 
595 /*ARGSUSED*/
596 static void
597 db_namecache_print_cmd(db_expr_t addr, int have_addr, db_expr_t count,
598     char *modif)
599 {
600 
601 	namecache_print((struct vnode *)(intptr_t) addr, db_printf);
602 }
603 
604 /*ARGSUSED*/
605 static void
606 db_uvmexp_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
607 {
608 
609 	uvmexp_print(db_printf);
610 }
611 
612 /*
613  * Call random function:
614  * !expr(arg,arg,arg)
615  */
616 /*ARGSUSED*/
617 static void
618 db_fncall(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
619 {
620 	db_expr_t	fn_addr;
621 #define	MAXARGS		11
622 	db_expr_t	args[MAXARGS];
623 	int		nargs = 0;
624 	db_expr_t	retval;
625 	db_expr_t	(*func)(db_expr_t, ...);
626 	int		t;
627 
628 	if (!db_expression(&fn_addr)) {
629 		db_printf("Bad function\n");
630 		db_flush_lex();
631 		return;
632 	}
633 	func = (db_expr_t (*)(db_expr_t, ...))(intptr_t) fn_addr;
634 
635 	t = db_read_token();
636 	if (t == tLPAREN) {
637 		if (db_expression(&args[0])) {
638 			nargs++;
639 			while ((t = db_read_token()) == tCOMMA) {
640 				if (nargs == MAXARGS) {
641 					db_printf("Too many arguments\n");
642 					db_flush_lex();
643 					return;
644 				}
645 				if (!db_expression(&args[nargs])) {
646 					db_printf("Argument missing\n");
647 					db_flush_lex();
648 					return;
649 				}
650 				nargs++;
651 			}
652 			db_unread_token(t);
653 		}
654 		if (db_read_token() != tRPAREN) {
655 			db_printf("?\n");
656 			db_flush_lex();
657 			return;
658 		}
659 	}
660 	db_skip_to_eol();
661 
662 	while (nargs < MAXARGS) {
663 		args[nargs++] = 0;
664 	}
665 
666 	retval = (*func)(args[0], args[1], args[2], args[3], args[4],
667 			 args[5], args[6], args[7], args[8], args[9]);
668 	db_printf("%s\n", db_num_to_str(retval));
669 }
670 
671 static void
672 db_reboot_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
673 {
674 	db_expr_t bootflags;
675 
676 	/* Flags, default to RB_AUTOBOOT */
677 	if (!db_expression(&bootflags))
678 		bootflags = (db_expr_t)RB_AUTOBOOT;
679 	if (db_read_token() != tEOL) {
680 		db_error("?\n");
681 		/*NOTREACHED*/
682 	}
683 	/*
684 	 * We are leaving DDB, never to return upward.
685 	 * Clear db_recover so that we can debug faults in functions
686 	 * called from cpu_reboot.
687 	 */
688 	db_recover = 0;
689 	cpu_reboot((int)bootflags, NULL);
690 }
691 
692 static void
693 db_sifting_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
694 {
695 	int	mode, t;
696 
697 	t = db_read_token();
698 	if (t == tSLASH) {
699 		t = db_read_token();
700 		if (t != tIDENT) {
701 			bad_modifier:
702 			db_printf("Bad modifier\n");
703 			db_flush_lex();
704 			return;
705 		}
706 		if (!strcmp(db_tok_string, "F"))
707 			mode = 'F';
708 		else
709 			goto bad_modifier;
710 		t = db_read_token();
711 	} else
712 		mode = 0;
713 
714 	if (t == tIDENT)
715 		db_sifting(db_tok_string, mode);
716 	else {
717 		db_printf("Bad argument (non-string)\n");
718 		db_flush_lex();
719 	}
720 }
721 
722 static void
723 db_stack_trace_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
724 {
725 	register char *cp = modif;
726 	register char c;
727 	void (*pr)(const char *, ...);
728 
729 	pr = db_printf;
730 	while ((c = *cp++) != 0)
731 		if (c == 'l')
732 			pr = printf;
733 
734 	if (count == -1)
735 		count = 65535;
736 
737 	db_stack_trace_print(addr, have_addr, count, modif, pr);
738 }
739 
740 static void
741 db_sync_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
742 {
743 
744 	/*
745 	 * We are leaving DDB, never to return upward.
746 	 * Clear db_recover so that we can debug faults in functions
747 	 * called from cpu_reboot.
748 	 */
749 	db_recover = 0;
750 	cpu_reboot(RB_DUMP, NULL);
751 }
752