xref: /freebsd/sys/ddb/db_command.c (revision 5f757f3ff9144b609b3c433dfd370cc6bdc191ad)
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  * Command dispatcher.
34  */
35 
36 #include <sys/param.h>
37 #include <sys/conf.h>
38 #include <sys/cons.h>
39 #include <sys/eventhandler.h>
40 #include <sys/kdb.h>
41 #include <sys/kernel.h>
42 #include <sys/linker_set.h>
43 #include <sys/lock.h>
44 #include <sys/mutex.h>
45 #include <sys/proc.h>
46 #include <sys/reboot.h>
47 #include <sys/signalvar.h>
48 #include <sys/systm.h>
49 #include <sys/watchdog.h>
50 
51 #include <ddb/ddb.h>
52 #include <ddb/db_command.h>
53 #include <ddb/db_lex.h>
54 #include <ddb/db_output.h>
55 
56 #include <machine/cpu.h>
57 #include <machine/setjmp.h>
58 
59 #include <security/mac/mac_framework.h>
60 
61 /*
62  * Exported global variables
63  */
64 int		db_cmd_loop_done;
65 db_addr_t	db_dot;
66 db_addr_t	db_last_addr;
67 db_addr_t	db_prev;
68 db_addr_t	db_next;
69 
70 static db_cmdfcn_t	db_dump;
71 static db_cmdfcn_t	db_fncall;
72 static db_cmdfcn_t	db_gdb;
73 static db_cmdfcn_t	db_halt;
74 static db_cmdfcn_t	db_kill;
75 static db_cmdfcn_t	db_reset;
76 static db_cmdfcn_t	db_stack_trace;
77 static db_cmdfcn_t	db_stack_trace_active;
78 static db_cmdfcn_t	db_stack_trace_all;
79 static db_cmdfcn_t	db_watchdog;
80 
81 #define	DB_CMD(_name, _func, _flags)	\
82 {					\
83 	.name =	(_name),		\
84 	.fcn =	(_func),		\
85 	.flag =	(_flags),		\
86 	.more = NULL,			\
87 }
88 #define	DB_TABLE(_name, _more)		\
89 {					\
90 	.name =	(_name),		\
91 	.fcn =	NULL,			\
92 	.more =	(_more),		\
93 }
94 
95 static struct db_command db_show_active_cmds[] = {
96 	DB_CMD("trace",		db_stack_trace_active,	DB_CMD_MEMSAFE),
97 };
98 struct db_command_table db_show_active_table =
99     LIST_HEAD_INITIALIZER(db_show_active_table);
100 
101 static struct db_command db_show_all_cmds[] = {
102 	DB_CMD("trace",		db_stack_trace_all,	DB_CMD_MEMSAFE),
103 };
104 struct db_command_table db_show_all_table =
105     LIST_HEAD_INITIALIZER(db_show_all_table);
106 
107 static struct db_command db_show_cmds[] = {
108 	DB_TABLE("active",	&db_show_active_table),
109 	DB_TABLE("all",		&db_show_all_table),
110 	DB_CMD("registers",	db_show_regs,		DB_CMD_MEMSAFE),
111 	DB_CMD("breaks",	db_listbreak_cmd,	DB_CMD_MEMSAFE),
112 	DB_CMD("threads",	db_show_threads,	DB_CMD_MEMSAFE),
113 };
114 struct db_command_table db_show_table = LIST_HEAD_INITIALIZER(db_show_table);
115 
116 static struct db_command db_cmds[] = {
117 	DB_TABLE("show",	&db_show_table),
118 	DB_CMD("print",		db_print_cmd,		0),
119 	DB_CMD("p",		db_print_cmd,		0),
120 	DB_CMD("examine",	db_examine_cmd,		CS_SET_DOT),
121 	DB_CMD("x",		db_examine_cmd,		CS_SET_DOT),
122 	DB_CMD("search",	db_search_cmd,		CS_OWN|CS_SET_DOT),
123 	DB_CMD("set",		db_set_cmd,		CS_OWN|DB_CMD_MEMSAFE),
124 	DB_CMD("write",		db_write_cmd,		CS_MORE|CS_SET_DOT),
125 	DB_CMD("w",		db_write_cmd,		CS_MORE|CS_SET_DOT),
126 	DB_CMD("delete",	db_delete_cmd,		0),
127 	DB_CMD("d",		db_delete_cmd,		0),
128 	DB_CMD("dump",		db_dump,		DB_CMD_MEMSAFE),
129 	DB_CMD("break",		db_breakpoint_cmd,	0),
130 	DB_CMD("b",		db_breakpoint_cmd,	0),
131 	DB_CMD("dwatch",	db_deletewatch_cmd,	0),
132 	DB_CMD("watch",		db_watchpoint_cmd,	CS_MORE),
133 	DB_CMD("dhwatch",	db_deletehwatch_cmd,	0),
134 	DB_CMD("hwatch",	db_hwatchpoint_cmd,	0),
135 	DB_CMD("step",		db_single_step_cmd,	DB_CMD_MEMSAFE),
136 	DB_CMD("s",		db_single_step_cmd,	DB_CMD_MEMSAFE),
137 	DB_CMD("continue",	db_continue_cmd,	DB_CMD_MEMSAFE),
138 	DB_CMD("c",		db_continue_cmd,	DB_CMD_MEMSAFE),
139 	DB_CMD("until",		db_trace_until_call_cmd, DB_CMD_MEMSAFE),
140 	DB_CMD("next",		db_trace_until_matching_cmd, DB_CMD_MEMSAFE),
141 	DB_CMD("match",		db_trace_until_matching_cmd, 0),
142 	DB_CMD("trace",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
143 	DB_CMD("t",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
144 	/* XXX alias for active trace */
145 	DB_CMD("acttrace",	db_stack_trace_active,	DB_CMD_MEMSAFE),
146 	/* XXX alias for all trace */
147 	DB_CMD("alltrace",	db_stack_trace_all,	DB_CMD_MEMSAFE),
148 	DB_CMD("where",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
149 	DB_CMD("bt",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
150 	DB_CMD("call",		db_fncall,		CS_OWN),
151 	DB_CMD("ps",		db_ps,			DB_CMD_MEMSAFE),
152 	DB_CMD("gdb",		db_gdb,			0),
153 	DB_CMD("halt",		db_halt,		DB_CMD_MEMSAFE),
154 	DB_CMD("reboot",	db_reset,		DB_CMD_MEMSAFE),
155 	DB_CMD("reset",		db_reset,		DB_CMD_MEMSAFE),
156 	DB_CMD("kill",		db_kill,		CS_OWN|DB_CMD_MEMSAFE),
157 	DB_CMD("watchdog",	db_watchdog,		CS_OWN|DB_CMD_MEMSAFE),
158 	DB_CMD("thread",	db_set_thread,		0),
159 	DB_CMD("run",		db_run_cmd,		CS_OWN|DB_CMD_MEMSAFE),
160 	DB_CMD("script",	db_script_cmd,		CS_OWN|DB_CMD_MEMSAFE),
161 	DB_CMD("scripts",	db_scripts_cmd,		DB_CMD_MEMSAFE),
162 	DB_CMD("unscript",	db_unscript_cmd,	CS_OWN|DB_CMD_MEMSAFE),
163 	DB_CMD("capture",	db_capture_cmd,		CS_OWN|DB_CMD_MEMSAFE),
164 	DB_CMD("textdump",	db_textdump_cmd,	CS_OWN|DB_CMD_MEMSAFE),
165 	DB_CMD("findstack",	db_findstack_cmd,	0),
166 	DB_CMD("pprint",	db_pprint_cmd,		CS_OWN),
167 };
168 struct db_command_table db_cmd_table = LIST_HEAD_INITIALIZER(db_cmd_table);
169 
170 #undef DB_CMD
171 #undef DB_TABLE
172 
173 static struct db_command *db_last_command = NULL;
174 
175 /*
176  * if 'ed' style: 'dot' is set at start of last item printed,
177  * and '+' points to next line.
178  * Otherwise: 'dot' points to next item, '..' points to last.
179  */
180 static bool	db_ed_style = true;
181 
182 /*
183  * Utility routine - discard tokens through end-of-line.
184  */
185 void
186 db_skip_to_eol(void)
187 {
188 	int t;
189 
190 	do {
191 		t = db_read_token();
192 	} while (t != tEOL);
193 }
194 
195 /*
196  * Results of command search.
197  */
198 #define	CMD_UNIQUE	0
199 #define	CMD_FOUND	1
200 #define	CMD_NONE	2
201 #define	CMD_AMBIGUOUS	3
202 #define	CMD_HELP	4
203 
204 static void	db_cmd_match(char *name, struct db_command *cmd,
205 		    struct db_command **cmdp, int *resultp);
206 static void	db_cmd_list(struct db_command_table *table);
207 static int	db_cmd_search(char *name, struct db_command_table *table,
208 		    struct db_command **cmdp);
209 static void	db_command(struct db_command **last_cmdp,
210 		    struct db_command_table *cmd_table, bool dopager);
211 
212 /*
213  * Initialize the command lists from the static tables.
214  */
215 void
216 db_command_init(void)
217 {
218 	int i;
219 
220 	for (i = 0; i < nitems(db_cmds); i++)
221 		db_command_register(&db_cmd_table, &db_cmds[i]);
222 	for (i = 0; i < nitems(db_show_cmds); i++)
223 		db_command_register(&db_show_table, &db_show_cmds[i]);
224 	for (i = 0; i < nitems(db_show_active_cmds); i++)
225 		db_command_register(&db_show_active_table,
226 		    &db_show_active_cmds[i]);
227 	for (i = 0; i < nitems(db_show_all_cmds); i++)
228 		db_command_register(&db_show_all_table, &db_show_all_cmds[i]);
229 }
230 
231 /*
232  * Register a command.
233  */
234 void
235 db_command_register(struct db_command_table *list, struct db_command *cmd)
236 {
237 	struct db_command *c, *last;
238 
239 #ifdef MAC
240 	if (mac_ddb_command_register(list, cmd)) {
241 		printf("%s: MAC policy refused registration of command %s\n",
242 		    __func__, cmd->name);
243 		return;
244 	}
245 #endif
246 	last = NULL;
247 	LIST_FOREACH(c, list, next) {
248 		int n = strcmp(cmd->name, c->name);
249 
250 		/* Check that the command is not already present. */
251 		if (n == 0) {
252 			printf("%s: Warning, the command \"%s\" already exists;"
253 			     " ignoring request\n", __func__, cmd->name);
254 			return;
255 		}
256 		if (n < 0) {
257 			/* NB: keep list sorted lexicographically */
258 			LIST_INSERT_BEFORE(c, cmd, next);
259 			return;
260 		}
261 		last = c;
262 	}
263 	if (last == NULL)
264 		LIST_INSERT_HEAD(list, cmd, next);
265 	else
266 		LIST_INSERT_AFTER(last, cmd, next);
267 }
268 
269 /*
270  * Remove a command previously registered with db_command_register.
271  */
272 void
273 db_command_unregister(struct db_command_table *list, struct db_command *cmd)
274 {
275 	struct db_command *c;
276 
277 	LIST_FOREACH(c, list, next) {
278 		if (cmd == c) {
279 			LIST_REMOVE(cmd, next);
280 			return;
281 		}
282 	}
283 	/* NB: intentionally quiet */
284 }
285 
286 /*
287  * Helper function to match a single command.
288  */
289 static void
290 db_cmd_match(char *name, struct db_command *cmd, struct db_command **cmdp,
291     int *resultp)
292 {
293 	char *lp, *rp;
294 	int c;
295 
296 	lp = name;
297 	rp = cmd->name;
298 	while ((c = *lp) == *rp) {
299 		if (c == 0) {
300 			/* complete match */
301 			*cmdp = cmd;
302 			*resultp = CMD_UNIQUE;
303 			return;
304 		}
305 		lp++;
306 		rp++;
307 	}
308 	if (c == 0) {
309 		/* end of name, not end of command -
310 		   partial match */
311 		if (*resultp == CMD_FOUND) {
312 			*resultp = CMD_AMBIGUOUS;
313 			/* but keep looking for a full match -
314 			   this lets us match single letters */
315 		} else if (*resultp == CMD_NONE) {
316 			*cmdp = cmd;
317 			*resultp = CMD_FOUND;
318 		}
319 	}
320 }
321 
322 /*
323  * Search for command prefix.
324  */
325 static int
326 db_cmd_search(char *name, struct db_command_table *table,
327     struct db_command **cmdp)
328 {
329 	struct db_command *cmd;
330 	int result = CMD_NONE;
331 
332 	LIST_FOREACH(cmd, table, next) {
333 		db_cmd_match(name,cmd,cmdp,&result);
334 		if (result == CMD_UNIQUE)
335 			break;
336 	}
337 
338 	if (result == CMD_NONE) {
339 		/* check for 'help' */
340 		if (name[0] == 'h' && name[1] == 'e'
341 		    && name[2] == 'l' && name[3] == 'p')
342 			result = CMD_HELP;
343 	}
344 	return (result);
345 }
346 
347 static void
348 db_cmd_list(struct db_command_table *table)
349 {
350 	struct db_command *cmd;
351 	int have_subcommands;
352 
353 	have_subcommands = 0;
354 	LIST_FOREACH(cmd, table, next) {
355 		if (cmd->more != NULL)
356 			have_subcommands++;
357 		db_printf("%-16s", cmd->name);
358 		db_end_line(16);
359 	}
360 
361 	if (have_subcommands > 0) {
362 		db_printf("\nThe following have subcommands; append \"help\" "
363 		    "to list (e.g. \"show help\"):\n");
364 		LIST_FOREACH(cmd, table, next) {
365 			if (cmd->more == NULL)
366 				continue;
367 			db_printf("%-16s", cmd->name);
368 			db_end_line(16);
369 		}
370 	}
371 }
372 
373 static void
374 db_command(struct db_command **last_cmdp, struct db_command_table *cmd_table,
375     bool dopager)
376 {
377 	char modif[TOK_STRING_SIZE];
378 	struct db_command *cmd = NULL;
379 	db_expr_t addr, count;
380 	int t, result;
381 	bool have_addr = false;
382 
383 	t = db_read_token();
384 	if (t == tEOL) {
385 		/* empty line repeats last command, at 'next' */
386 		cmd = *last_cmdp;
387 		addr = (db_expr_t)db_next;
388 		have_addr = false;
389 		count = 1;
390 		modif[0] = '\0';
391 	} else if (t == tEXCL) {
392 		db_fncall((db_expr_t)0, false, (db_expr_t)0, NULL);
393 		return;
394 	} else if (t != tIDENT) {
395 		db_printf("Unrecognized input; use \"help\" "
396 	            "to list available commands\n");
397 		db_flush_lex();
398 		return;
399 	} else {
400 		/*
401 		 * Search for command
402 		 */
403 		while (cmd_table != NULL) {
404 			result = db_cmd_search(db_tok_string, cmd_table, &cmd);
405 			switch (result) {
406 			case CMD_NONE:
407 				db_printf("No such command; use \"help\" "
408 				    "to list available commands\n");
409 				db_flush_lex();
410 				return;
411 			case CMD_AMBIGUOUS:
412 				db_printf("Ambiguous\n");
413 				db_flush_lex();
414 				return;
415 			case CMD_HELP:
416 				if (cmd_table == &db_cmd_table) {
417 					db_printf("This is ddb(4), the kernel debugger; "
418 					    "see https://man.FreeBSD.org/ddb/4 for help.\n");
419 					db_printf("Use \"bt\" for backtrace, \"dump\" for "
420 					    "kernel core dump, \"reset\" to reboot.\n");
421 					db_printf("Available commands:\n");
422 				}
423 				db_cmd_list(cmd_table);
424 				db_flush_lex();
425 				return;
426 			case CMD_UNIQUE:
427 			case CMD_FOUND:
428 				break;
429 			}
430 			if ((cmd_table = cmd->more) != NULL) {
431 				t = db_read_token();
432 				if (t != tIDENT) {
433 					db_printf("Subcommand required; "
434 					    "available subcommands:\n");
435 					db_cmd_list(cmd_table);
436 					db_flush_lex();
437 					return;
438 				}
439 			}
440 		}
441 
442 		if ((cmd->flag & CS_OWN) == 0) {
443 			/*
444 			 * Standard syntax:
445 			 * command [/modifier] [addr] [,count]
446 			 */
447 			t = db_read_token();
448 			if (t == tSLASH) {
449 				t = db_read_token();
450 				if (t != tIDENT) {
451 					db_printf("Bad modifier\n");
452 					db_flush_lex();
453 					return;
454 				}
455 				db_strcpy(modif, db_tok_string);
456 			} else {
457 				db_unread_token(t);
458 				modif[0] = '\0';
459 			}
460 
461 			if (db_expression(&addr)) {
462 				db_dot = (db_addr_t) addr;
463 				db_last_addr = db_dot;
464 				have_addr = true;
465 			} else {
466 				addr = (db_expr_t) db_dot;
467 				have_addr = false;
468 			}
469 
470 			t = db_read_token();
471 			if (t == tCOMMA) {
472 				if (!db_expression(&count)) {
473 					db_printf("Count missing\n");
474 					db_flush_lex();
475 					return;
476 				}
477 			} else {
478 				db_unread_token(t);
479 				count = -1;
480 			}
481 
482 			if ((cmd->flag & CS_MORE) == 0) {
483 				db_skip_to_eol();
484 			}
485 		}
486 	}
487 
488 	*last_cmdp = cmd;
489 	if (cmd != NULL) {
490 #ifdef MAC
491 		if (mac_ddb_command_exec(cmd, addr, have_addr, count, modif)) {
492 			db_printf("MAC prevented execution of command %s\n",
493 			    cmd->name);
494 			return;
495 		}
496 #endif
497 		/*
498 		 * Execute the command.
499 		 */
500 		if (dopager)
501 			db_enable_pager();
502 		else
503 			db_disable_pager();
504 		(*cmd->fcn)(addr, have_addr, count, modif);
505 		if (dopager)
506 			db_disable_pager();
507 
508 		if (cmd->flag & CS_SET_DOT) {
509 			/*
510 			 * If command changes dot, set dot to previous address
511 			 * displayed (if 'ed' style).
512 			 */
513 			db_dot = db_ed_style ? db_prev : db_next;
514 		} else {
515 			/*
516 			 * If command does not change dot, set 'next' location
517 			 * to be the same.
518 			 */
519 			db_next = db_dot;
520 		}
521 	}
522 }
523 
524 /*
525  * At least one non-optional command must be implemented using
526  * DB_COMMAND() so that db_cmd_set gets created.  Here is one.
527  */
528 DB_COMMAND_FLAGS(panic, db_panic, DB_CMD_MEMSAFE)
529 {
530 	db_disable_pager();
531 	panic("from debugger");
532 }
533 
534 void
535 db_command_loop(void)
536 {
537 	/*
538 	 * Initialize 'prev' and 'next' to dot.
539 	 */
540 	db_prev = db_dot;
541 	db_next = db_dot;
542 
543 	db_cmd_loop_done = 0;
544 	while (!db_cmd_loop_done) {
545 		if (db_print_position() != 0)
546 			db_printf("\n");
547 
548 		db_printf("db> ");
549 		(void)db_read_line();
550 
551 		db_command(&db_last_command, &db_cmd_table, /* dopager */ true);
552 	}
553 }
554 
555 /*
556  * Execute a command on behalf of a script.  The caller is responsible for
557  * making sure that the command string is < DB_MAXLINE or it will be
558  * truncated.
559  *
560  * XXXRW: Runs by injecting faked input into DDB input stream; it would be
561  * nicer to use an alternative approach that didn't mess with the previous
562  * command buffer.
563  */
564 void
565 db_command_script(const char *command)
566 {
567 	db_prev = db_next = db_dot;
568 	db_inject_line(command);
569 	db_command(&db_last_command, &db_cmd_table, /* dopager */ false);
570 }
571 
572 void
573 db_error(const char *s)
574 {
575 	if (s)
576 	    db_printf("%s", s);
577 	db_flush_lex();
578 	kdb_reenter_silent();
579 }
580 
581 static void
582 db_dump(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
583 {
584 	int error;
585 
586 	if (textdump_pending) {
587 		db_printf("textdump_pending set.\n"
588 		    "run \"textdump unset\" first or \"textdump dump\" for a textdump.\n");
589 		return;
590 	}
591 	error = doadump(false);
592 	if (error) {
593 		db_printf("Cannot dump: ");
594 		switch (error) {
595 		case EBUSY:
596 			db_printf("debugger got invoked while dumping.\n");
597 			break;
598 		case ENXIO:
599 			db_printf("no dump device specified.\n");
600 			break;
601 		default:
602 			db_printf("unknown error (error=%d).\n", error);
603 			break;
604 		}
605 	}
606 }
607 
608 /*
609  * Call random function:
610  * !expr(arg,arg,arg)
611  */
612 
613 /* The generic implementation supports a maximum of 10 arguments. */
614 typedef db_expr_t __db_f(db_expr_t, db_expr_t, db_expr_t, db_expr_t,
615     db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t);
616 
617 static __inline int
618 db_fncall_generic(db_expr_t addr, db_expr_t *rv, int nargs, db_expr_t args[])
619 {
620 	__db_f *f = (__db_f *)addr;
621 
622 	if (nargs > 10) {
623 		db_printf("Too many arguments (max 10)\n");
624 		return (0);
625 	}
626 	*rv = (*f)(args[0], args[1], args[2], args[3], args[4], args[5],
627 	    args[6], args[7], args[8], args[9]);
628 	return (1);
629 }
630 
631 static void
632 db_fncall(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
633 {
634 	db_expr_t	fn_addr;
635 	db_expr_t	args[DB_MAXARGS];
636 	int		nargs = 0;
637 	db_expr_t	retval;
638 	int		t;
639 
640 	if (!db_expression(&fn_addr)) {
641 	    db_printf("Bad function\n");
642 	    db_flush_lex();
643 	    return;
644 	}
645 
646 	t = db_read_token();
647 	if (t == tLPAREN) {
648 	    if (db_expression(&args[0])) {
649 		nargs++;
650 		while ((t = db_read_token()) == tCOMMA) {
651 		    if (nargs == DB_MAXARGS) {
652 			db_printf("Too many arguments (max %d)\n", DB_MAXARGS);
653 			db_flush_lex();
654 			return;
655 		    }
656 		    if (!db_expression(&args[nargs])) {
657 			db_printf("Argument missing\n");
658 			db_flush_lex();
659 			return;
660 		    }
661 		    nargs++;
662 		}
663 		db_unread_token(t);
664 	    }
665 	    if (db_read_token() != tRPAREN) {
666 	        db_printf("Mismatched parens\n");
667 		db_flush_lex();
668 		return;
669 	    }
670 	}
671 	db_skip_to_eol();
672 	db_disable_pager();
673 
674 	if (DB_CALL(fn_addr, &retval, nargs, args))
675 		db_printf("= %#lr\n", (long)retval);
676 }
677 
678 static void
679 db_halt(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
680 {
681 
682 	cpu_halt();
683 }
684 
685 static void
686 db_kill(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
687 {
688 	db_expr_t old_radix, pid, sig;
689 	struct proc *p;
690 
691 #define	DB_ERROR(f)	do { db_printf f; db_flush_lex(); goto out; } while (0)
692 
693 	/*
694 	 * PIDs and signal numbers are typically represented in base
695 	 * 10, so make that the default here.  It can, of course, be
696 	 * overridden by specifying a prefix.
697 	 */
698 	old_radix = db_radix;
699 	db_radix = 10;
700 	/* Retrieve arguments. */
701 	if (!db_expression(&sig))
702 		DB_ERROR(("Missing signal number\n"));
703 	if (!db_expression(&pid))
704 		DB_ERROR(("Missing process ID\n"));
705 	db_skip_to_eol();
706 	if (!_SIG_VALID(sig))
707 		DB_ERROR(("Signal number out of range\n"));
708 
709 	/*
710 	 * Find the process in question.  allproc_lock is not needed
711 	 * since we're in DDB.
712 	 */
713 	/* sx_slock(&allproc_lock); */
714 	FOREACH_PROC_IN_SYSTEM(p)
715 	    if (p->p_pid == pid)
716 		    break;
717 	/* sx_sunlock(&allproc_lock); */
718 	if (p == NULL)
719 		DB_ERROR(("Can't find process with pid %ld\n", (long) pid));
720 
721 	/* If it's already locked, bail; otherwise, do the deed. */
722 	if (PROC_TRYLOCK(p) == 0)
723 		DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
724 	else {
725 		pksignal(p, sig, NULL);
726 		PROC_UNLOCK(p);
727 	}
728 
729 out:
730 	db_radix = old_radix;
731 #undef DB_ERROR
732 }
733 
734 /*
735  * Reboot.  In case there is an additional argument, take it as delay in
736  * seconds.  Default to 15s if we cannot parse it and make sure we will
737  * never wait longer than 1 week.  Some code is similar to
738  * kern_shutdown.c:shutdown_panic().
739  */
740 #ifndef	DB_RESET_MAXDELAY
741 #define	DB_RESET_MAXDELAY	(3600 * 24 * 7)
742 #endif
743 
744 static void
745 db_reset(db_expr_t addr, bool have_addr, db_expr_t count __unused,
746     char *modif)
747 {
748 	int delay, loop;
749 
750 	if (have_addr) {
751 		delay = (int)db_hex2dec(addr);
752 
753 		/* If we parse to fail, use 15s. */
754 		if (delay == -1)
755 			delay = 15;
756 
757 		/* Cap at one week. */
758 		if ((uintmax_t)delay > (uintmax_t)DB_RESET_MAXDELAY)
759 			delay = DB_RESET_MAXDELAY;
760 
761 		db_printf("Automatic reboot in %d seconds - "
762 		    "press a key on the console to abort\n", delay);
763 		for (loop = delay * 10; loop > 0; --loop) {
764 			DELAY(1000 * 100); /* 1/10th second */
765 			/* Did user type a key? */
766 			if (cncheckc() != -1)
767 				return;
768 		}
769 	}
770 
771 	/*
772 	 * Conditionally try the standard reboot path, so any registered
773 	 * shutdown/reset handlers have a chance to run first. Some platforms
774 	 * may not support the machine-dependent mechanism used by cpu_reset()
775 	 * and rely on some other non-standard mechanism to perform the reset.
776 	 * For example, the BCM2835 watchdog driver or gpio-poweroff driver.
777 	 */
778 	if (modif[0] != 's') {
779 		kern_reboot(RB_NOSYNC);
780 		/* NOTREACHED */
781 	}
782 
783 	cpu_reset();
784 }
785 
786 static void
787 db_watchdog(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
788 {
789 	db_expr_t old_radix, tout;
790 	int err, i;
791 
792 	old_radix = db_radix;
793 	db_radix = 10;
794 	err = db_expression(&tout);
795 	db_skip_to_eol();
796 	db_radix = old_radix;
797 
798 	/* If no argument is provided the watchdog will just be disabled. */
799 	if (err == 0) {
800 		db_printf("No argument provided, disabling watchdog\n");
801 		tout = 0;
802 	} else if ((tout & WD_INTERVAL) == WD_TO_NEVER) {
803 		db_error("Out of range watchdog interval\n");
804 		return;
805 	}
806 	EVENTHANDLER_INVOKE(watchdog_list, tout, &i);
807 }
808 
809 static void
810 db_gdb(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
811 {
812 
813 	if (kdb_dbbe_select("gdb") != 0) {
814 		db_printf("The remote GDB backend could not be selected.\n");
815 		return;
816 	}
817 	/*
818 	 * Mark that we are done in the debugger.  kdb_trap()
819 	 * should re-enter with the new backend.
820 	 */
821 	db_cmd_loop_done = 1;
822 	db_printf("(ctrl-c will return control to ddb)\n");
823 }
824 
825 static void
826 db_stack_trace(db_expr_t tid, bool hastid, db_expr_t count, char *modif)
827 {
828 	struct thread *td;
829 	db_expr_t radix;
830 	pid_t pid;
831 	int t;
832 
833 	/*
834 	 * We parse our own arguments. We don't like the default radix.
835 	 */
836 	radix = db_radix;
837 	db_radix = 10;
838 	hastid = db_expression(&tid);
839 	t = db_read_token();
840 	if (t == tCOMMA) {
841 		if (!db_expression(&count)) {
842 			db_printf("Count missing\n");
843 			db_flush_lex();
844 			db_radix = radix;
845 			return;
846 		}
847 	} else {
848 		db_unread_token(t);
849 		count = -1;
850 	}
851 	db_skip_to_eol();
852 	db_radix = radix;
853 
854 	if (hastid) {
855 		td = kdb_thr_lookup((lwpid_t)tid);
856 		if (td == NULL)
857 			td = kdb_thr_from_pid((pid_t)tid);
858 		if (td == NULL) {
859 			db_printf("Thread %d not found\n", (int)tid);
860 			return;
861 		}
862 	} else
863 		td = kdb_thread;
864 	if (td->td_proc != NULL)
865 		pid = td->td_proc->p_pid;
866 	else
867 		pid = -1;
868 	db_printf("Tracing pid %d tid %ld td %p\n", pid, (long)td->td_tid, td);
869 	if (td->td_proc != NULL && (td->td_proc->p_flag & P_INMEM) == 0)
870 		db_printf("--- swapped out\n");
871 	else
872 		db_trace_thread(td, count);
873 }
874 
875 static void
876 _db_stack_trace_all(bool active_only)
877 {
878 	struct thread *td;
879 	jmp_buf jb;
880 	void *prev_jb;
881 
882 	for (td = kdb_thr_first(); td != NULL; td = kdb_thr_next(td)) {
883 		prev_jb = kdb_jmpbuf(jb);
884 		if (setjmp(jb) == 0) {
885 			if (TD_IS_RUNNING(td))
886 				db_printf("\nTracing command %s pid %d"
887 				    " tid %ld td %p (CPU %d)\n",
888 				    td->td_proc->p_comm, td->td_proc->p_pid,
889 				    (long)td->td_tid, td, td->td_oncpu);
890 			else if (active_only)
891 				continue;
892 			else
893 				db_printf("\nTracing command %s pid %d"
894 				    " tid %ld td %p\n", td->td_proc->p_comm,
895 				    td->td_proc->p_pid, (long)td->td_tid, td);
896 			if (td->td_proc->p_flag & P_INMEM)
897 				db_trace_thread(td, -1);
898 			else
899 				db_printf("--- swapped out\n");
900 			if (db_pager_quit) {
901 				kdb_jmpbuf(prev_jb);
902 				return;
903 			}
904 		}
905 		kdb_jmpbuf(prev_jb);
906 	}
907 }
908 
909 static void
910 db_stack_trace_active(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
911     char *dummy4)
912 {
913 
914 	_db_stack_trace_all(true);
915 }
916 
917 static void
918 db_stack_trace_all(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
919     char *dummy4)
920 {
921 
922 	_db_stack_trace_all(false);
923 }
924 
925 /*
926  * Take the parsed expression value from the command line that was parsed
927  * as a hexadecimal value and convert it as if the expression was parsed
928  * as a decimal value.  Returns -1 if the expression was not a valid
929  * decimal value.
930  */
931 db_expr_t
932 db_hex2dec(db_expr_t expr)
933 {
934 	uintptr_t x, y;
935 	db_expr_t val;
936 
937 	y = 1;
938 	val = 0;
939 	x = expr;
940 	while (x != 0) {
941 		if (x % 16 > 9)
942 			return (-1);
943 		val += (x % 16) * (y);
944 		x >>= 4;
945 		y *= 10;
946 	}
947 	return (val);
948 }
949