xref: /netbsd-src/sys/ddb/db_command.c (revision 500db002748d9818288e46e10f026a2b09548086)
1 /*	$NetBSD: db_command.c,v 1.130 2009/03/11 13:29:44 nakayama Exp $	*/
2 /*
3  * Mach Operating System
4  * Copyright (c) 1991,1990 Carnegie Mellon University
5  * All Rights Reserved.
6  *
7  * Permission to use, copy, modify and distribute this software and its
8  * documentation is hereby granted, provided that both the copyright
9  * notice and this permission notice appear in all copies of the
10  * software, derivative works or modified versions, and any portions
11  * thereof, and that both notices appear in supporting documentation.
12  *
13  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
14  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
15  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
16  *
17  * Carnegie Mellon requests users of this software to return to
18  *
19  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
20  *  School of Computer Science
21  *  Carnegie Mellon University
22  *  Pittsburgh PA 15213-3890
23  *
24  * any improvements or extensions that they make and grant Carnegie the
25  * rights to redistribute these changes.
26  */
27 /*
28  * Copyright (c) 1996, 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
29  * All rights reserved.
30  *
31  * This code is derived from software contributed to The NetBSD Foundation
32  * by Adam Hamsik.
33  *
34  * Redistribution and use in source and binary forms, with or without
35  * modification, are permitted provided that the following conditions
36  * are met:
37  * 1. Redistributions of source code must retain the above copyright
38  *    notice, this list of conditions and the following disclaimer.
39  * 2. Redistributions in binary form must reproduce the above copyright
40  *    notice, this list of conditions and the following disclaimer in the
41  *    documentation and/or other materials provided with the distribution.
42  *
43  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
44  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
45  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
46  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
47  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
48  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
49  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
50  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
51  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
52  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
53  * POSSIBILITY OF SUCH DAMAGE.
54  */
55 
56 /*
57  * Command dispatcher.
58  */
59 
60 #include <sys/cdefs.h>
61 __KERNEL_RCSID(0, "$NetBSD: db_command.c,v 1.130 2009/03/11 13:29:44 nakayama Exp $");
62 
63 #ifdef _KERNEL_OPT
64 #include "opt_aio.h"
65 #include "opt_ddb.h"
66 #include "opt_kgdb.h"
67 #include "opt_inet.h"
68 #include "opt_uvmhist.h"
69 #include "opt_ddbparam.h"
70 #include "opt_multiprocessor.h"
71 #include "arp.h"
72 #endif
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/reboot.h>
77 #include <sys/device.h>
78 #include <sys/lwp.h>
79 #include <sys/malloc.h>
80 #include <sys/mbuf.h>
81 #include <sys/namei.h>
82 #include <sys/pool.h>
83 #include <sys/proc.h>
84 #include <sys/vnode.h>
85 #include <sys/vmem.h>
86 #include <sys/lockdebug.h>
87 #include <sys/cpu.h>
88 #include <sys/buf.h>
89 #include <sys/module.h>
90 
91 /*include queue macros*/
92 #include <sys/queue.h>
93 
94 #include <ddb/ddb.h>
95 
96 #include <uvm/uvm_extern.h>
97 #include <uvm/uvm_ddb.h>
98 
99 /*
100  * Results of command search.
101  */
102 #define	CMD_EXACT		0
103 #define	CMD_PREFIX		1
104 #define	CMD_NONE		2
105 #define	CMD_AMBIGUOUS	3
106 
107 /*
108  * Exported global variables
109  */
110 bool		db_cmd_loop_done;
111 label_t		*db_recover;
112 db_addr_t	db_dot;
113 db_addr_t	db_last_addr;
114 db_addr_t	db_prev;
115 db_addr_t	db_next;
116 
117 
118 /*
119  * New DDB api for adding and removing commands uses three lists, because
120  * we use two types of commands
121  * a) standard commands without subcommands -> reboot
122  * b) show commands which are subcommands of show command -> show aio_jobs
123  * c) if defined machine specific commands
124  *
125  * ddb_add_cmd, ddb_rem_cmd use type (DDB_SHOW_CMD||DDB_BASE_CMD)argument to
126  * add them to representativ lists.
127  */
128 
129 static const struct db_command db_command_table[];
130 static const struct db_command db_show_cmds[];
131 
132 #ifdef DB_MACHINE_COMMANDS
133 static const struct db_command db_machine_command_table[];
134 #endif
135 
136 /* the global queue of all command tables */
137 TAILQ_HEAD(db_cmd_tbl_en_head, db_cmd_tbl_en);
138 
139 /* TAILQ entry used to register command tables */
140 struct db_cmd_tbl_en {
141 	const struct db_command *db_cmd;	/* cmd table */
142 	TAILQ_ENTRY(db_cmd_tbl_en) db_cmd_next;
143 };
144 
145 /* head of base commands list */
146 static struct db_cmd_tbl_en_head db_base_cmd_list =
147 	TAILQ_HEAD_INITIALIZER(db_base_cmd_list);
148 static struct db_cmd_tbl_en db_base_cmd_builtins =
149      { .db_cmd = db_command_table };
150 
151 /* head of show commands list */
152 static struct db_cmd_tbl_en_head db_show_cmd_list =
153 	TAILQ_HEAD_INITIALIZER(db_show_cmd_list);
154 static struct db_cmd_tbl_en db_show_cmd_builtins =
155      { .db_cmd = db_show_cmds };
156 
157 /* head of machine commands list */
158 static struct db_cmd_tbl_en_head db_mach_cmd_list =
159 	TAILQ_HEAD_INITIALIZER(db_mach_cmd_list);
160 #ifdef DB_MACHINE_COMMANDS
161 static struct db_cmd_tbl_en db_mach_cmd_builtins =
162      { .db_cmd = db_machine_command_table };
163 #endif
164 
165 /*
166  * if 'ed' style: 'dot' is set at start of last item printed,
167  * and '+' points to next line.
168  * Otherwise: 'dot' points to next item, '..' points to last.
169  */
170 static bool	 db_ed_style = true;
171 
172 static void	db_init_commands(void);
173 static int	db_register_tbl_entry(uint8_t type,
174     struct db_cmd_tbl_en *list_ent);
175 static void	db_cmd_list(const struct db_cmd_tbl_en_head *);
176 static int	db_cmd_search(const char *, struct db_cmd_tbl_en_head *,
177 			      const struct db_command **);
178 static int	db_cmd_search_table(const char *, const struct db_command *,
179 				    const struct db_command **);
180 static void	db_cmd_search_failed(char *, int);
181 static const struct db_command *db_read_command(void);
182 static void	db_command(const struct db_command **);
183 static void	db_buf_print_cmd(db_expr_t, bool, db_expr_t, const char *);
184 static void	db_event_print_cmd(db_expr_t, bool, db_expr_t, const char *);
185 static void	db_fncall(db_expr_t, bool, db_expr_t, const char *);
186 static void     db_help_print_cmd(db_expr_t, bool, db_expr_t, const char *);
187 static void	db_lock_print_cmd(db_expr_t, bool, db_expr_t, const char *);
188 static void	db_mount_print_cmd(db_expr_t, bool, db_expr_t, const char *);
189 static void	db_mbuf_print_cmd(db_expr_t, bool, db_expr_t, const char *);
190 static void	db_malloc_print_cmd(db_expr_t, bool, db_expr_t, const char *);
191 static void	db_map_print_cmd(db_expr_t, bool, db_expr_t, const char *);
192 static void	db_namecache_print_cmd(db_expr_t, bool, db_expr_t,
193 		    const char *);
194 static void	db_object_print_cmd(db_expr_t, bool, db_expr_t, const char *);
195 static void	db_page_print_cmd(db_expr_t, bool, db_expr_t, const char *);
196 static void	db_show_all_pages(db_expr_t, bool, db_expr_t, const char *);
197 static void	db_pool_print_cmd(db_expr_t, bool, db_expr_t, const char *);
198 static void	db_reboot_cmd(db_expr_t, bool, db_expr_t, const char *);
199 static void	db_sifting_cmd(db_expr_t, bool, db_expr_t, const char *);
200 static void	db_stack_trace_cmd(db_expr_t, bool, db_expr_t, const char *);
201 static void	db_sync_cmd(db_expr_t, bool, db_expr_t, const char *);
202 static void	db_whatis_cmd(db_expr_t, bool, db_expr_t, const char *);
203 static void	db_uvmexp_print_cmd(db_expr_t, bool, db_expr_t, const char *);
204 #ifdef UVMHIST
205 static void	db_uvmhist_print_cmd(db_expr_t, bool, db_expr_t, const char *);
206 #endif
207 static void	db_vnode_print_cmd(db_expr_t, bool, db_expr_t, const char *);
208 static void	db_vmem_print_cmd(db_expr_t, bool, db_expr_t, const char *);
209 
210 static const struct db_command db_show_cmds[] = {
211 	/*added from all sub cmds*/
212 #ifdef _KERNEL	/* XXX CRASH(8) */
213 	{ DDB_ADD_CMD("callout",  db_show_callout,
214 	    0 ,"List all used callout functions.",NULL,NULL) },
215 #endif
216 	{ DDB_ADD_CMD("pages",	db_show_all_pages,
217 	    0 ,"List all used memory pages.",NULL,NULL) },
218 	{ DDB_ADD_CMD("procs",	db_show_all_procs,
219 	    0 ,"List all processes.",NULL,NULL) },
220 	{ DDB_ADD_CMD("pools",	db_show_all_pools,
221 	    0 ,"Show all poolS",NULL,NULL) },
222 #ifdef AIO
223 	/*added from all sub cmds*/
224 	{ DDB_ADD_CMD("aio_jobs",	db_show_aio_jobs,	0,
225 	    "Show aio jobs",NULL,NULL) },
226 #endif
227 	{ DDB_ADD_CMD("all",	NULL,
228 	    CS_COMPAT, NULL,NULL,NULL) },
229 #if defined(INET) && (NARP > 0)
230 	{ DDB_ADD_CMD("arptab",	db_show_arptab,		0,NULL,NULL,NULL) },
231 #endif
232 #ifdef _KERNEL
233 	{ DDB_ADD_CMD("breaks",	db_listbreak_cmd, 	0,
234 	    "Display all breaks.",NULL,NULL) },
235 #endif
236 	{ DDB_ADD_CMD("buf",	db_buf_print_cmd,	0,
237 	    "Print the struct buf at address.", "[/f] address",NULL) },
238 	{ DDB_ADD_CMD("event",	db_event_print_cmd,	0,
239 	    "Print all the non-zero evcnt(9) event counters.", "[/f]",NULL) },
240 	{ DDB_ADD_CMD("files", db_show_files_cmd,	0,
241 	    "Print the files open by process at address",
242 	    "[/f] address", NULL) },
243 	{ DDB_ADD_CMD("lock",	db_lock_print_cmd,	0,NULL,NULL,NULL) },
244 	{ DDB_ADD_CMD("malloc",	db_malloc_print_cmd,0,NULL,NULL,NULL) },
245 	{ DDB_ADD_CMD("map",	db_map_print_cmd,	0,
246 	    "Print the vm_map at address.", "[/f] address",NULL) },
247 	{ DDB_ADD_CMD("module", db_show_module_cmd,	0,
248 	    "Print kernel modules", NULL, NULL) },
249 	{ DDB_ADD_CMD("mount",	db_mount_print_cmd,	0,
250 	    "Print the mount structure at address.", "[/f] address",NULL) },
251 	{ DDB_ADD_CMD("mqueue", db_show_mqueue_cmd,	0,
252 	    "Print the message queues", NULL, NULL) },
253 	{ DDB_ADD_CMD("mbuf",	db_mbuf_print_cmd,	0,NULL,NULL,
254 	    "-c prints all mbuf chains") },
255 	{ DDB_ADD_CMD("ncache",	db_namecache_print_cmd,	0,
256 	    "Dump the namecache list.", "address",NULL) },
257 	{ DDB_ADD_CMD("object",	db_object_print_cmd,	0,
258 	    "Print the vm_object at address.", "[/f] address",NULL) },
259 	{ DDB_ADD_CMD("page",	db_page_print_cmd,	0,
260 	    "Print the vm_page at address.", "[/f] address",NULL) },
261 	{ DDB_ADD_CMD("pool",	db_pool_print_cmd,	0,
262 	    "Print the pool at address.", "[/clp] address",NULL) },
263 	{ DDB_ADD_CMD("registers",	db_show_regs,		0,
264 	    "Display the register set.", "[/u]",NULL) },
265 	{ DDB_ADD_CMD("sched_qs",	db_show_sched_qs,	0,
266 	    "Print the state of the scheduler's run queues.",
267 	    NULL,NULL) },
268 	{ DDB_ADD_CMD("uvmexp",	db_uvmexp_print_cmd, 0,
269 	    "Print a selection of UVM counters and statistics.",
270 	    NULL,NULL) },
271 #ifdef UVMHIST
272 	{ DDB_ADD_CMD("uvmhist", db_uvmhist_print_cmd, 0,
273 	    "Print the UVM history logs.",
274 	    NULL,NULL) },
275 #endif
276 	{ DDB_ADD_CMD("vnode",	db_vnode_print_cmd,	0,
277 	    "Print the vnode at address.", "[/f] address",NULL) },
278 	{ DDB_ADD_CMD("vmem", db_vmem_print_cmd,	0,
279 	    "Print the vmem usage.", "[/a] address", NULL) },
280 	{ DDB_ADD_CMD("vmems", db_show_all_vmems,	0,
281 	    "Show all vmems.", NULL, NULL) },
282 #ifdef _KERNEL
283 	{ DDB_ADD_CMD("watches",	db_listwatch_cmd, 	0,
284 	    "Display all watchpoints.", NULL,NULL) },
285 #endif
286 	{ DDB_ADD_CMD(NULL,		NULL,			0,NULL,NULL,NULL) }
287 };
288 
289 /* arch/<arch>/<arch>/db_interface.c */
290 #ifdef DB_MACHINE_COMMANDS
291 extern const struct db_command db_machine_command_table[];
292 #endif
293 
294 static const struct db_command db_command_table[] = {
295 	{ DDB_ADD_CMD("b",		db_breakpoint_cmd,	0,
296 	    "Set a breakpoint at address", "[/u] address[,count].",NULL) },
297 	{ DDB_ADD_CMD("break",	db_breakpoint_cmd,	0,
298 	    "Set a breakpoint at address", "[/u] address[,count].",NULL) },
299 	{ DDB_ADD_CMD("bt",		db_stack_trace_cmd,	0,
300 	    "Show backtrace.", "See help trace.",NULL) },
301 	{ DDB_ADD_CMD("c",		db_continue_cmd,	0,
302 	    "Continue execution.", "[/c]",NULL) },
303 	{ DDB_ADD_CMD("call",	db_fncall,		CS_OWN,
304 	    "Call the function", "address[(expression[,...])]",NULL) },
305 #ifdef _KERNEL	/* XXX CRASH(8) */
306 	{ DDB_ADD_CMD("callout",	db_show_callout,	0, NULL,
307 	    NULL,NULL ) },
308 #endif
309 	{ DDB_ADD_CMD("continue",	db_continue_cmd,	0,
310 	    "Continue execution.", "[/c]",NULL) },
311 	{ DDB_ADD_CMD("d",		db_delete_cmd,		0,
312 	    "Delete a breakpoint.", "address | #number",NULL) },
313 	{ DDB_ADD_CMD("delete",	db_delete_cmd,		0,
314 	    "Delete a breakpoint.", "address | #number",NULL) },
315 	{ DDB_ADD_CMD("dmesg",	db_dmesg,		0,
316 	    "Show kernel message buffer.", "[count]",NULL) },
317 	{ DDB_ADD_CMD("dwatch",	db_deletewatch_cmd,	0,
318 	    "Delete the watchpoint.", "address",NULL) },
319 	{ DDB_ADD_CMD("examine",	db_examine_cmd,		CS_SET_DOT,
320 	    "Display the address locations.",
321 	    "[/modifier] address[,count]",NULL) },
322 	{ DDB_ADD_CMD("exit",		db_continue_cmd,	0,
323 	    "Continue execution.", "[/c]",NULL) },
324 	{ DDB_ADD_CMD("help",   db_help_print_cmd, CS_OWN|CS_NOREPEAT,
325 	    "Display help about commands",
326 	    "Use other commands as arguments.",NULL) },
327 	{ DDB_ADD_CMD("kill",	db_kill_proc,		CS_OWN,
328 	    "Send a signal to the process","pid[,signal_number]",
329 	    "   pid:\t\t\tthe process id (may need 0t prefix for decimal)\n"
330 	    "   signal_number:\tthe signal to send") },
331 #ifdef KGDB
332 	{ DDB_ADD_CMD("kgdb",	db_kgdb_cmd,	0,	NULL,NULL,NULL) },
333 #endif
334 	{ DDB_ADD_CMD("machine",NULL,CS_MACH,
335 	    "Architecture specific functions.",NULL,NULL) },
336 	{ DDB_ADD_CMD("match",	db_trace_until_matching_cmd,0,
337 	    "Stop at the matching return instruction.","See help next",NULL) },
338 	{ DDB_ADD_CMD("next",	db_trace_until_matching_cmd,0,
339 	    "Stop at the matching return instruction.","[/p]",NULL) },
340 	{ DDB_ADD_CMD("p",		db_print_cmd,		0,
341 	    "Print address according to the format.",
342 	    "[/axzodurc] address [address ...]",NULL) },
343 	{ DDB_ADD_CMD("print",	db_print_cmd,		0,
344 	    "Print address according to the format.",
345 	    "[/axzodurc] address [address ...]",NULL) },
346 	{ DDB_ADD_CMD("ps",		db_show_all_procs,	0,
347 	    "Print all processes.","See show all procs",NULL) },
348 	{ DDB_ADD_CMD("quit",		db_continue_cmd,	0,
349 	    "Continue execution.", "[/c]",NULL) },
350 	{ DDB_ADD_CMD("reboot",	db_reboot_cmd,		CS_OWN,
351 	    "Reboot","0x1  RB_ASKNAME, 0x2 RB_SINGLE, 0x4 RB_NOSYNC, 0x8 RB_HALT,"
352 	    "0x40 RB_KDB, 0x100 RB_DUMP, 0x808 RB_POWERDOWN",NULL) },
353 	{ DDB_ADD_CMD("s",		db_single_step_cmd,	0,
354 	    "Single-step count times.","[/p] [,count]",NULL) },
355 	{ DDB_ADD_CMD("search",	db_search_cmd,		CS_OWN|CS_SET_DOT,
356 	    "Search memory from address for value.",
357 	    "[/bhl] address value [mask] [,count]",NULL) },
358 	{ DDB_ADD_CMD("set",	db_set_cmd,		CS_OWN,
359 	    "Set the named variable","$variable [=] expression",NULL) },
360 	{ DDB_ADD_CMD("show",	NULL, CS_SHOW,
361 	    "Show kernel stats.", NULL,NULL) },
362 	{ DDB_ADD_CMD("sifting",	db_sifting_cmd,		CS_OWN,
363 	    "Search the symbol tables ","[/F] string",NULL) },
364 	{ DDB_ADD_CMD("step",	db_single_step_cmd,	0,
365 	    "Single-step count times.","[/p] [,count]",NULL) },
366 	{ DDB_ADD_CMD("sync",	db_sync_cmd,		CS_OWN,
367 	    "Force a crash dump, and then reboot.",NULL,NULL) },
368 	{ DDB_ADD_CMD("trace",	db_stack_trace_cmd,	0,
369 	    "Stack trace from frame-address.",
370 	    "[/u[l]] [frame-address][,count]",NULL) },
371 	{ DDB_ADD_CMD("until",	db_trace_until_call_cmd,0,
372 	    "Stop at the next call or return instruction.","[/p]",NULL) },
373 	{ DDB_ADD_CMD("w",		db_write_cmd,		CS_MORE|CS_SET_DOT,
374 	    "Write the expressions at succeeding locations.",
375 	    "[/bhl] address expression [expression ...]",NULL) },
376 	{ DDB_ADD_CMD("watch",	db_watchpoint_cmd,	CS_MORE,
377 	    "Set a watchpoint for a region. ","address[,size]",NULL) },
378 	{ DDB_ADD_CMD("whatis",	db_whatis_cmd, 0,
379 	    "Describe what an address is", "address", NULL) },
380 	{ DDB_ADD_CMD("write",	db_write_cmd,		CS_MORE|CS_SET_DOT,
381 	    "Write the expressions at succeeding locations.",
382 	    "[/bhl] address expression [expression ...]",NULL) },
383 	{ DDB_ADD_CMD("x",		db_examine_cmd,		CS_SET_DOT,
384 	    "Display the address locations.",
385 	    "[/modifier] address[,count]",NULL) },
386 	{ DDB_ADD_CMD(NULL, 	NULL,		   0, NULL, NULL, NULL) }
387 };
388 
389 static const struct db_command	*db_last_command = NULL;
390 #if defined(DDB_COMMANDONENTER)
391 char db_cmd_on_enter[DB_LINE_MAXLEN + 1] = ___STRING(DDB_COMMANDONENTER);
392 #else /* defined(DDB_COMMANDONENTER) */
393 char db_cmd_on_enter[DB_LINE_MAXLEN + 1] = "";
394 #endif /* defined(DDB_COMMANDONENTER) */
395 #define	DB_LINE_SEP	';'
396 
397 /*
398  * Execute commandlist after ddb start
399  * This function goes through the command list created from commands and ';'
400  */
401 static void
402 db_execute_commandlist(const char *cmdlist)
403 {
404 	const char *cmd = cmdlist;
405 	const struct db_command	*dummy = NULL;
406 
407 	while (*cmd != '\0') {
408 		const char *ep = cmd;
409 
410 		while (*ep != '\0' && *ep != DB_LINE_SEP) {
411 			ep++;
412 		}
413 		db_set_line(cmd, ep);
414 		db_command(&dummy);
415 		cmd = ep;
416 		if (*cmd == DB_LINE_SEP) {
417 			cmd++;
418 		}
419 	}
420 }
421 
422 /* Initialize ddb command tables */
423 void
424 db_init_commands(void)
425 {
426 	static bool done = false;
427 
428 	if (done) return;
429 	done = true;
430 
431 	/* register command tables */
432 	(void)db_register_tbl_entry(DDB_BASE_CMD, &db_base_cmd_builtins);
433 #ifdef DB_MACHINE_COMMANDS
434 	(void)db_register_tbl_entry(DDB_MACH_CMD, &db_mach_cmd_builtins);
435 #endif
436 	(void)db_register_tbl_entry(DDB_SHOW_CMD, &db_show_cmd_builtins);
437 }
438 
439 
440 /*
441  * Add command table to the specified list
442  * Arg:
443  * int type specifies type of command table DDB_SHOW_CMD|DDB_BASE_CMD|DDB_MAC_CMD
444  * *cmd_tbl poiter to static allocated db_command table
445  *
446  * Command table must be NULL terminated array of struct db_command
447  */
448 int
449 db_register_tbl(uint8_t type, const struct db_command *cmd_tbl)
450 {
451 	struct db_cmd_tbl_en *list_ent;
452 
453 	/* empty list - ignore */
454 	if (cmd_tbl->name == 0)
455 		return 0;
456 
457 	/* force builtin commands to be registered first */
458 	db_init_commands();
459 
460 	/* now create a list entry for this table */
461 	list_ent = db_zalloc(sizeof(*list_ent));
462 	if (list_ent == NULL)
463 		return ENOMEM;
464 	list_ent->db_cmd=cmd_tbl;
465 
466 	/* and register it */
467 	return db_register_tbl_entry(type, list_ent);
468 }
469 
470 static int
471 db_register_tbl_entry(uint8_t type, struct db_cmd_tbl_en *list_ent)
472 {
473 	struct db_cmd_tbl_en_head *list;
474 
475 	switch(type) {
476 	case DDB_BASE_CMD:
477 		list = &db_base_cmd_list;
478 		break;
479 	case DDB_SHOW_CMD:
480 		list = &db_show_cmd_list;
481 		break;
482 	case DDB_MACH_CMD:
483 		list = &db_mach_cmd_list;
484 		break;
485 	default:
486 		return ENOENT;
487 	}
488 
489 	TAILQ_INSERT_TAIL(list, list_ent, db_cmd_next);
490 
491 	return 0;
492 }
493 
494 /*
495  * Remove command table specified with db_cmd address == cmd_tbl
496  */
497 int
498 db_unregister_tbl(uint8_t type,const struct db_command *cmd_tbl)
499 {
500 	struct db_cmd_tbl_en *list_ent;
501 	struct db_cmd_tbl_en_head *list;
502 
503 	/* find list on which the entry should live */
504 	switch (type) {
505 	case DDB_BASE_CMD:
506 		list=&db_base_cmd_list;
507 		break;
508 	case DDB_SHOW_CMD:
509 		list=&db_show_cmd_list;
510 		break;
511 	case DDB_MACH_CMD:
512 		list=&db_mach_cmd_list;
513 		break;
514 	default:
515 		return EINVAL;
516 	}
517 
518 	TAILQ_FOREACH (list_ent, list, db_cmd_next) {
519 		if (list_ent->db_cmd == cmd_tbl){
520 			TAILQ_REMOVE(list,
521 			    list_ent, db_cmd_next);
522 			db_free(list_ent, sizeof(*list_ent));
523 			return 0;
524 		}
525 	}
526 	return ENOENT;
527 }
528 
529 /* This function is called from machine trap code. */
530 void
531 db_command_loop(void)
532 {
533 	label_t	db_jmpbuf;
534 	label_t	*savejmp;
535 
536 	/*
537 	 * Initialize 'prev' and 'next' to dot.
538 	 */
539 	db_prev = db_dot;
540 	db_next = db_dot;
541 
542 	db_cmd_loop_done = false;
543 
544 	/* Init default command tables add machine, base,
545 	   show command tables to the list */
546 	db_init_commands();
547 
548 	/* save context for return from ddb */
549 	savejmp = db_recover;
550 	db_recover = &db_jmpbuf;
551 	(void) setjmp(&db_jmpbuf);
552 
553 	/* Execute default ddb start commands */
554 	db_execute_commandlist(db_cmd_on_enter);
555 
556 	(void) setjmp(&db_jmpbuf);
557 	while (!db_cmd_loop_done) {
558 		if (db_print_position() != 0)
559 			db_printf("\n");
560 		db_output_line = 0;
561 		(void) db_read_line();
562 		db_command(&db_last_command);
563 	}
564 
565 	db_recover = savejmp;
566 }
567 
568 /*
569  * Search command table for command prefix
570  */
571 static int
572 db_cmd_search_table(const char *name,
573 		    const struct db_command *table,
574 		    const struct db_command **cmdp)
575 {
576 
577 	const struct db_command	*cmd;
578 	int result;
579 
580 	result = CMD_NONE;
581 	*cmdp = NULL;
582 
583 	for (cmd = table; cmd->name != 0; cmd++) {
584 		const char *lp;
585 		const char *rp;
586 
587 		lp = name;
588 		rp = cmd->name;
589 		while (*lp != '\0' && *lp == *rp) {
590 			rp++;
591 			lp++;
592 		}
593 
594 		if (*lp != '\0') /* mismatch or extra chars in name */
595 			continue;
596 
597 		if (*rp == '\0') { /* exact match */
598 			*cmdp = cmd;
599 			return (CMD_EXACT);
600 		}
601 
602 		/* prefix match: end of name, not end of command */
603 		if (result == CMD_NONE) {
604 			result = CMD_PREFIX;
605 			*cmdp = cmd;
606 		}
607 		else if (result == CMD_PREFIX) {
608 			result = CMD_AMBIGUOUS;
609 			*cmdp = NULL;
610 		}
611 	}
612 
613 	return (result);
614 }
615 
616 
617 /*
618  * Search list of command tables for command
619  */
620 static int
621 db_cmd_search(const char *name,
622 	      struct db_cmd_tbl_en_head *list_head,
623 	      const struct db_command **cmdp)
624 {
625 	struct db_cmd_tbl_en *list_ent;
626 	const struct db_command *found_command;
627 	bool accept_prefix_match;
628 	int result;
629 
630 	result = CMD_NONE;
631 	found_command = NULL;
632 	accept_prefix_match = true;
633 
634 	TAILQ_FOREACH(list_ent, list_head, db_cmd_next) {
635 		const struct db_command *cmd;
636 		int found;
637 
638 		found = db_cmd_search_table(name, list_ent->db_cmd, &cmd);
639 		if (found == CMD_EXACT) {
640 			result = CMD_EXACT;
641 			found_command = cmd;
642 			break;
643 		}
644 
645 		if (found == CMD_PREFIX) {
646 			if (accept_prefix_match) {
647 				/*
648 				 * Continue search, but note current result
649 				 * in case we won't find anything else.
650 				 */
651 				accept_prefix_match = false;
652 				result = CMD_PREFIX;
653 				found_command = cmd;
654 			} else {
655 				/*
656 				 * Watch out for globally ambiguous
657 				 * prefix match that is not locally
658 				 * ambiguous - with one match in one
659 				 * table and another match(es) in
660 				 * another table.
661 				 */
662 				result = CMD_AMBIGUOUS;
663 				found_command = NULL;
664 			}
665 		}
666 		else if (found == CMD_AMBIGUOUS) {
667 			accept_prefix_match = false;
668 			result = CMD_AMBIGUOUS;
669 			found_command = NULL;
670 		}
671 	}
672 
673 	*cmdp = found_command;
674 	return result;
675 }
676 
677 static void
678 db_cmd_search_failed(char *name, int search_result)
679 {
680 	if (search_result == CMD_NONE)
681 		db_printf("No such command: %s\n", name);
682 	else
683 		db_printf("Ambiguous command: %s\n", name);
684 }
685 
686 
687 /*
688  * List commands to the console.
689  */
690 static void
691 db_cmd_list(const struct db_cmd_tbl_en_head *list)
692 {
693 
694 	struct db_cmd_tbl_en *list_ent;
695 	const struct db_command *table;
696 	size_t		i, j, w, columns, lines, numcmds, width=0;
697 	const char	*p;
698 
699 	TAILQ_FOREACH(list_ent,list,db_cmd_next) {
700 		table = list_ent->db_cmd;
701 		for (i = 0; table[i].name != NULL; i++) {
702 			w = strlen(table[i].name);
703 			if (w > width)
704 				width = w;
705 		}
706 	}
707 
708 	width = DB_NEXT_TAB(width);
709 
710 	columns = db_max_width / width;
711 	if (columns == 0)
712 		columns = 1;
713 
714 	TAILQ_FOREACH(list_ent,list,db_cmd_next) {
715 		table = list_ent->db_cmd;
716 
717 		for (numcmds = 0; table[numcmds].name != NULL; numcmds++)
718 			;
719 		lines = (numcmds + columns - 1) / columns;
720 
721 		for (i = 0; i < lines; i++) {
722 			for (j = 0; j < columns; j++) {
723 				p = table[j * lines + i].name;
724 				if (p)
725 					db_printf("%s", p);
726 				if (j * lines + i + lines >= numcmds) {
727 					db_putchar('\n');
728 					break;
729 				}
730 				if (p) {
731 					w = strlen(p);
732 					while (w < width) {
733 						w = DB_NEXT_TAB(w);
734 						db_putchar('\t');
735 					}
736 				}
737 			}
738 		}
739 	}
740 	return;
741 }
742 
743 /*
744  * Read complete command with all subcommands, starting with current
745  * db_tok_string. If subcommand is missing, print the list of all
746  * subcommands.  If command/subcommand is not found, print an error
747  * message.  Returns pointer to "leaf" command or NULL.
748  */
749 static const struct db_command *
750 db_read_command(void)
751 {
752 	const struct db_command *command;
753 	struct db_cmd_tbl_en_head *list;
754 	int found;
755 	int t;
756 
757 	list = &db_base_cmd_list;
758 	do {
759 		found = db_cmd_search(db_tok_string, list, &command);
760 		if (command == NULL) {
761 			db_cmd_search_failed(db_tok_string, found);
762 			db_flush_lex();
763 			return NULL;
764 		}
765 
766 		if (command->flag == CS_SHOW)
767 			list = &db_show_cmd_list;
768 		else if (command->flag == CS_MACH)
769 			list = &db_mach_cmd_list;
770 		else if (command->flag == CS_COMPAT)
771 			/* same list */;
772 		else
773 			break; /* expect no more subcommands */
774 
775 		t = db_read_token(); /* read subcommand */
776 		if (t != tIDENT) {
777 			/* if none given - just print all of them */
778 			db_cmd_list(list);
779 			db_flush_lex();
780 			return NULL;
781 		}
782 	} while (list != NULL);
783 
784 	return command;
785 }
786 
787 /*
788  * Parse command line and execute apropriate function.
789  */
790 static void
791 db_command(const struct db_command **last_cmdp)
792 {
793 	const struct db_command *command;
794 	static db_expr_t last_count = 0;
795 	db_expr_t	addr, count;
796 	char		modif[TOK_STRING_SIZE];
797 
798 	int			t;
799 	bool		have_addr = false;
800 
801 	command = NULL;
802 
803 	t = db_read_token();
804 	if ((t == tEOL) || (t == tCOMMA)) {
805 		/*
806 		 * An empty line repeats last command, at 'next'.
807 		 * Only a count repeats the last command with the new count.
808 		 */
809 		command = *last_cmdp;
810 
811 		if (!command)
812 			return;
813 
814 		addr = (db_expr_t)db_next;
815 		if (t == tCOMMA) {
816 			if (!db_expression(&count)) {
817 				db_printf("Count missing\n");
818 				db_flush_lex();
819 				return;
820 			}
821 		} else
822 			count = last_count;
823 		have_addr = false;
824 		modif[0] = '\0';
825 		db_skip_to_eol();
826 
827 	} else if (t == tEXCL) {
828 		db_fncall(0, 0, 0, NULL);
829 		return;
830 
831 	} else if (t != tIDENT) {
832 		db_printf("?\n");
833 		db_flush_lex();
834 		return;
835 
836 	} else {
837 
838 		command = db_read_command();
839 		if (command == NULL)
840 			return;
841 
842 		if ((command->flag & CS_OWN) == 0) {
843 
844 			/*
845 			 * Standard syntax:
846 			 * command [/modifier] [addr] [,count]
847 			 */
848 			t = db_read_token(); /* get modifier */
849 			if (t == tSLASH) {
850 				t = db_read_token();
851 				if (t != tIDENT) {
852 					db_printf("Bad modifier\n");
853 					db_flush_lex();
854 					return;
855 				}
856 				/* save modifier */
857 				strlcpy(modif, db_tok_string, sizeof(modif));
858 
859 			} else {
860 				db_unread_token(t);
861 				modif[0] = '\0';
862 			}
863 
864 			if (db_expression(&addr)) { /*get address*/
865 				db_dot = (db_addr_t) addr;
866 				db_last_addr = db_dot;
867 				have_addr = true;
868 			} else {
869 				addr = (db_expr_t) db_dot;
870 				have_addr = false;
871 			}
872 
873 			t = db_read_token();
874 			if (t == tCOMMA) { /*Get count*/
875 				if (!db_expression(&count)) {
876 					db_printf("Count missing\n");
877 					db_flush_lex();
878 					return;
879 				}
880 			} else {
881 				db_unread_token(t);
882 				count = -1;
883 			}
884 			if ((command->flag & CS_MORE) == 0) {
885 				db_skip_to_eol();
886 			}
887 		}
888 	}
889 
890 	if (command != NULL && command->flag & CS_NOREPEAT) {
891 		*last_cmdp = NULL;
892 		last_count = 0;
893 	} else {
894 		*last_cmdp = command;
895 		last_count = count;
896 	}
897 
898 
899 	if (command != NULL) {
900 		/*
901 		 * Execute the command.
902 		 */
903 		if (command->fcn != NULL)
904 			(*command->fcn)(addr, have_addr, count, modif);
905 
906 		if (command->flag & CS_SET_DOT) {
907 			/*
908 			 * If command changes dot, set dot to
909 			 * previous address displayed (if 'ed' style).
910 			 */
911 			if (db_ed_style)
912 				db_dot = db_prev;
913 			else
914 				db_dot = db_next;
915 		} else {
916 			/*
917 			 * If command does not change dot,
918 			 * set 'next' location to be the same.
919 			 */
920 			db_next = db_dot;
921 		}
922 	}
923 }
924 
925 /*
926  * Print help for commands
927  */
928 static void
929 db_help_print_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
930 const char *modif)
931 {
932 	const struct db_command *command;
933 	int t;
934 
935 	t = db_read_token();
936 
937 	/* is there another command after the "help"? */
938 	if (t != tIDENT) {
939 		/* print base commands */
940 		db_cmd_list(&db_base_cmd_list);
941 		return;
942 	}
943 
944 	command = db_read_command();
945 	if (command == NULL)
946 		return;
947 
948 #ifdef DDB_VERBOSE_HELP
949 	db_printf("Command: %s\n", command->name);
950 	if (command->cmd_descr != NULL)
951 		db_printf(" Description: %s\n", command->cmd_descr);
952 	if (command->cmd_arg != NULL)
953 		db_printf(" Arguments: %s\n", command->cmd_arg);
954 	if (command->cmd_arg_help != NULL)
955 		db_printf(" Arguments description:\n%s\n",
956 			  command->cmd_arg_help);
957 	if ((command->cmd_arg == NULL) && (command->cmd_descr == NULL))
958 		db_printf(" No help message.\n");
959 #endif
960 
961 	db_skip_to_eol();
962 }
963 
964 /*ARGSUSED*/
965 static void
966 db_map_print_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
967     const char *modif)
968 {
969 	bool full = false;
970 
971 	if (modif[0] == 'f')
972 		full = true;
973 
974 	if (have_addr == false)
975 		addr = (db_expr_t)(uintptr_t)db_read_ptr("kernel_map");
976 
977 #ifdef _KERNEL
978 	uvm_map_printit((struct vm_map *)(uintptr_t) addr, full, db_printf);
979 #endif	/* XXX CRASH(8) */
980 }
981 
982 /*ARGSUSED*/
983 static void
984 db_malloc_print_cmd(db_expr_t addr, bool have_addr,
985     db_expr_t count, const char *modif)
986 {
987 
988 #ifdef MALLOC_DEBUG
989 	if (!have_addr)
990 		addr = 0;
991 
992 	debug_malloc_printit(db_printf, (vaddr_t) addr);
993 #else
994 	db_printf("The kernel is not built with the MALLOC_DEBUG option.\n");
995 #endif /* MALLOC_DEBUG */
996 }
997 
998 /*ARGSUSED*/
999 static void
1000 db_object_print_cmd(db_expr_t addr, bool have_addr,
1001     db_expr_t count, const char *modif)
1002 {
1003 	bool full = false;
1004 
1005 	if (modif[0] == 'f')
1006 		full = true;
1007 
1008 #ifdef _KERNEL /* XXX CRASH(8) */
1009 	uvm_object_printit((struct uvm_object *)(uintptr_t) addr, full,
1010 	    db_printf);
1011 #endif
1012 }
1013 
1014 /*ARGSUSED*/
1015 static void
1016 db_page_print_cmd(db_expr_t addr, bool have_addr,
1017     db_expr_t count, const char *modif)
1018 {
1019 	bool full = false;
1020 
1021 	if (modif[0] == 'f')
1022 		full = true;
1023 
1024 #ifdef _KERNEL /* XXX CRASH(8) */
1025 	uvm_page_printit((struct vm_page *)(uintptr_t) addr, full, db_printf);
1026 #endif
1027 }
1028 
1029 /*ARGSUSED*/
1030 static void
1031 db_show_all_pages(db_expr_t addr, bool have_addr,
1032     db_expr_t count, const char *modif)
1033 {
1034 
1035 #ifdef _KERNEL /* XXX CRASH(8) */
1036 	uvm_page_printall(db_printf);
1037 #endif
1038 }
1039 
1040 /*ARGSUSED*/
1041 static void
1042 db_buf_print_cmd(db_expr_t addr, bool have_addr,
1043     db_expr_t count, const char *modif)
1044 {
1045 	bool full = false;
1046 
1047 	if (modif[0] == 'f')
1048 		full = true;
1049 
1050 #ifdef _KERNEL /* XXX CRASH(8) */
1051 	vfs_buf_print((struct buf *)(uintptr_t) addr, full, db_printf);
1052 #endif
1053 }
1054 
1055 /*ARGSUSED*/
1056 static void
1057 db_event_print_cmd(db_expr_t addr, bool have_addr,
1058     db_expr_t count, const char *modif)
1059 {
1060 	bool full = false;
1061 
1062 	if (modif[0] == 'f')
1063 		full = true;
1064 
1065 #ifdef _KERNEL	/* XXX CRASH(8) */
1066 	event_print(full, db_printf);
1067 #endif
1068 }
1069 
1070 /*ARGSUSED*/
1071 static void
1072 db_vnode_print_cmd(db_expr_t addr, bool have_addr,
1073     db_expr_t count, const char *modif)
1074 {
1075 	bool full = false;
1076 
1077 	if (modif[0] == 'f')
1078 		full = true;
1079 
1080 #ifdef _KERNEL /* XXX CRASH(8) */
1081 	vfs_vnode_print((struct vnode *)(uintptr_t) addr, full, db_printf);
1082 #endif
1083 }
1084 
1085 /*ARGSUSED*/
1086 static void
1087 db_vmem_print_cmd(db_expr_t addr, bool have_addr,
1088     db_expr_t count, const char *modif)
1089 {
1090 
1091 #ifdef _KERNEL /* XXX CRASH(8) */
1092 	vmem_print((uintptr_t) addr, modif, db_printf);
1093 #endif
1094 }
1095 
1096 static void
1097 db_mount_print_cmd(db_expr_t addr, bool have_addr,
1098     db_expr_t count, const char *modif)
1099 {
1100 	bool full = false;
1101 
1102 	if (modif[0] == 'f')
1103 		full = true;
1104 
1105 #ifdef _KERNEL	/* XXX CRASH(8) */
1106 	vfs_mount_print((struct mount *)(uintptr_t) addr, full, db_printf);
1107 #endif
1108 }
1109 
1110 /*ARGSUSED*/
1111 static void
1112 db_mbuf_print_cmd(db_expr_t addr, bool have_addr,
1113     db_expr_t count, const char *modif)
1114 {
1115 
1116 #ifdef _KERNEL /* XXX CRASH(8) */
1117 	m_print((const struct mbuf *)(uintptr_t) addr, modif, db_printf);
1118 #endif
1119 }
1120 
1121 /*ARGSUSED*/
1122 static void
1123 db_pool_print_cmd(db_expr_t addr, bool have_addr,
1124     db_expr_t count, const char *modif)
1125 {
1126 
1127 #ifdef _KERNEL /* XXX CRASH(8) */
1128 	pool_printit((struct pool *)(uintptr_t) addr, modif, db_printf);
1129 #endif
1130 }
1131 
1132 /*ARGSUSED*/
1133 static void
1134 db_namecache_print_cmd(db_expr_t addr, bool have_addr,
1135     db_expr_t count, const char *modif)
1136 {
1137 
1138 #ifdef _KERNEL /* XXX CRASH(8) */
1139 	namecache_print((struct vnode *)(uintptr_t) addr, db_printf);
1140 #endif
1141 }
1142 
1143 /*ARGSUSED*/
1144 static void
1145 db_uvmexp_print_cmd(db_expr_t addr, bool have_addr,
1146     db_expr_t count, const char *modif)
1147 {
1148 
1149 #ifdef _KERNEL	/* XXX CRASH(8) */
1150 	uvmexp_print(db_printf);
1151 #endif
1152 }
1153 
1154 #ifdef UVMHIST
1155 /*ARGSUSED*/
1156 static void
1157 db_uvmhist_print_cmd(db_expr_t addr, bool have_addr,
1158     db_expr_t count, const char *modif)
1159 {
1160 
1161 	uvmhist_print(db_printf);
1162 }
1163 #endif
1164 
1165 /*ARGSUSED*/
1166 static void
1167 db_lock_print_cmd(db_expr_t addr, bool have_addr,
1168     db_expr_t count, const char *modif)
1169 {
1170 
1171 #ifdef _KERNEL	/* XXX CRASH(8) */
1172 	lockdebug_lock_print((void *)(uintptr_t)addr, db_printf);
1173 #endif
1174 }
1175 
1176 /*
1177  * Call random function:
1178  * !expr(arg,arg,arg)
1179  */
1180 /*ARGSUSED*/
1181 static void
1182 db_fncall(db_expr_t addr, bool have_addr,
1183     db_expr_t count, const char *modif)
1184 {
1185 #ifdef _KERNEL
1186 	db_expr_t	fn_addr;
1187 #define	MAXARGS		11
1188 	db_expr_t	args[MAXARGS];
1189 	int		nargs = 0;
1190 	db_expr_t	retval;
1191 	db_expr_t	(*func)(db_expr_t, ...);
1192 	int		t;
1193 
1194 	if (!db_expression(&fn_addr)) {
1195 		db_printf("Bad function\n");
1196 		db_flush_lex();
1197 		return;
1198 	}
1199 	func = (db_expr_t (*)(db_expr_t, ...))(uintptr_t) fn_addr;
1200 
1201 	t = db_read_token();
1202 	if (t == tLPAREN) {
1203 		if (db_expression(&args[0])) {
1204 			nargs++;
1205 			while ((t = db_read_token()) == tCOMMA) {
1206 				if (nargs == MAXARGS) {
1207 					db_printf("Too many arguments\n");
1208 					db_flush_lex();
1209 					return;
1210 				}
1211 				if (!db_expression(&args[nargs])) {
1212 					db_printf("Argument missing\n");
1213 					db_flush_lex();
1214 					return;
1215 				}
1216 				nargs++;
1217 			}
1218 			db_unread_token(t);
1219 		}
1220 		if (db_read_token() != tRPAREN) {
1221 			db_printf("?\n");
1222 			db_flush_lex();
1223 			return;
1224 		}
1225 	}
1226 	db_skip_to_eol();
1227 
1228 	while (nargs < MAXARGS) {
1229 		args[nargs++] = 0;
1230 	}
1231 
1232 	retval = (*func)(args[0], args[1], args[2], args[3], args[4],
1233 			 args[5], args[6], args[7], args[8], args[9]);
1234 	db_printf("%s\n", db_num_to_str(retval));
1235 #else	/* _KERNEL */
1236 	db_printf("This command can only be used in-kernel.\n");
1237 #endif	/* _KERNEL */
1238 }
1239 
1240 static void
1241 db_reboot_cmd(db_expr_t addr, bool have_addr,
1242     db_expr_t count, const char *modif)
1243 {
1244 #ifdef _KERNEL
1245 	db_expr_t bootflags;
1246 
1247 	/* Flags, default to RB_AUTOBOOT */
1248 	if (!db_expression(&bootflags))
1249 		bootflags = (db_expr_t)RB_AUTOBOOT;
1250 	if (db_read_token() != tEOL) {
1251 		db_error("?\n");
1252 		/*NOTREACHED*/
1253 	}
1254 	/*
1255 	 * We are leaving DDB, never to return upward.
1256 	 * Clear db_recover so that we can debug faults in functions
1257 	 * called from cpu_reboot.
1258 	 */
1259 	db_recover = 0;
1260 	cpu_reboot((int)bootflags, NULL);
1261 #else	/* _KERNEL */
1262 	db_printf("This command can only be used in-kernel.\n");
1263 #endif	/* _KERNEL */
1264 }
1265 
1266 static void
1267 db_sifting_cmd(db_expr_t addr, bool have_addr,
1268     db_expr_t count, const char *modif)
1269 {
1270 	int	mode, t;
1271 
1272 	t = db_read_token();
1273 	if (t == tSLASH) {
1274 		t = db_read_token();
1275 		if (t != tIDENT) {
1276 			bad_modifier:
1277 			db_printf("Bad modifier\n");
1278 			db_flush_lex();
1279 			return;
1280 		}
1281 		if (!strcmp(db_tok_string, "F"))
1282 			mode = 'F';
1283 		else
1284 			goto bad_modifier;
1285 		t = db_read_token();
1286 	} else
1287 		mode = 0;
1288 
1289 	if (t == tIDENT)
1290 		db_sifting(db_tok_string, mode);
1291 	else {
1292 		db_printf("Bad argument (non-string)\n");
1293 		db_flush_lex();
1294 	}
1295 }
1296 
1297 static void
1298 db_stack_trace_cmd(db_expr_t addr, bool have_addr, db_expr_t count, const char *modif)
1299 {
1300 	register const char *cp = modif;
1301 	register char c;
1302 	void (*pr)(const char *, ...);
1303 
1304 	pr = db_printf;
1305 	while ((c = *cp++) != 0)
1306 		if (c == 'l')
1307 			pr = (void (*)(const char *, ...))printf;
1308 
1309 	if (count == -1)
1310 		count = 65535;
1311 
1312 	db_stack_trace_print(addr, have_addr, count, modif, pr);
1313 }
1314 
1315 static void
1316 db_sync_cmd(db_expr_t addr, bool have_addr,
1317     db_expr_t count, const char *modif)
1318 {
1319 #ifdef _KERNEL
1320 	/*
1321 	 * We are leaving DDB, never to return upward.
1322 	 * Clear db_recover so that we can debug faults in functions
1323 	 * called from cpu_reboot.
1324 	 */
1325 	db_recover = 0;
1326 	panicstr = "dump forced via kernel debugger";
1327 	cpu_reboot(RB_DUMP, NULL);
1328 #else	/* _KERNEL */
1329 	db_printf("This command can only be used in-kernel.\n");
1330 #endif	/* _KERNEL */
1331 }
1332 
1333 /*
1334  * Describe what an address is
1335  */
1336 void
1337 db_whatis_cmd(db_expr_t address, bool have_addr,
1338     db_expr_t count, const char *modif)
1339 {
1340 	const uintptr_t addr = (uintptr_t)address;
1341 
1342 	db_lwp_whatis(addr, db_printf);
1343 #ifdef _KERNEL	/* XXX CRASH(8) */
1344 	pool_whatis(addr, db_printf);
1345 	vmem_whatis(addr, db_printf);
1346 	uvm_whatis(addr, db_printf);
1347 	module_whatis(addr, db_printf);
1348 #endif
1349 }
1350