xref: /freebsd/sys/ddb/db_command.c (revision e1e636193db45630c7881246d25902e57c43d24e)
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 #ifdef HAS_HW_BREAKPOINT
130 	DB_CMD("dhbreak",	db_deletehbreak_cmd,	0),
131 	DB_CMD("hbreak",	db_hbreakpoint_cmd,	0),
132 #endif
133 	DB_CMD("break",		db_breakpoint_cmd,	0),
134 	DB_CMD("b",		db_breakpoint_cmd,	0),
135 	DB_CMD("dwatch",	db_deletewatch_cmd,	0),
136 	DB_CMD("watch",		db_watchpoint_cmd,	CS_MORE),
137 	DB_CMD("dhwatch",	db_deletehwatch_cmd,	0),
138 	DB_CMD("hwatch",	db_hwatchpoint_cmd,	0),
139 	DB_CMD("step",		db_single_step_cmd,	DB_CMD_MEMSAFE),
140 	DB_CMD("s",		db_single_step_cmd,	DB_CMD_MEMSAFE),
141 	DB_CMD("continue",	db_continue_cmd,	DB_CMD_MEMSAFE),
142 	DB_CMD("c",		db_continue_cmd,	DB_CMD_MEMSAFE),
143 	DB_CMD("until",		db_trace_until_call_cmd, DB_CMD_MEMSAFE),
144 	DB_CMD("next",		db_trace_until_matching_cmd, DB_CMD_MEMSAFE),
145 	DB_CMD("match",		db_trace_until_matching_cmd, 0),
146 	DB_CMD("trace",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
147 	DB_CMD("t",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
148 	/* XXX alias for active trace */
149 	DB_CMD("acttrace",	db_stack_trace_active,	DB_CMD_MEMSAFE),
150 	/* XXX alias for all trace */
151 	DB_CMD("alltrace",	db_stack_trace_all,	DB_CMD_MEMSAFE),
152 	DB_CMD("where",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
153 	DB_CMD("bt",		db_stack_trace,		CS_OWN|DB_CMD_MEMSAFE),
154 	DB_CMD("call",		db_fncall,		CS_OWN),
155 	DB_CMD("ps",		db_ps,			DB_CMD_MEMSAFE),
156 	DB_CMD("gdb",		db_gdb,			0),
157 	DB_CMD("halt",		db_halt,		DB_CMD_MEMSAFE),
158 	DB_CMD("reboot",	db_reset,		DB_CMD_MEMSAFE),
159 	DB_CMD("reset",		db_reset,		DB_CMD_MEMSAFE),
160 	DB_CMD("kill",		db_kill,		CS_OWN|DB_CMD_MEMSAFE),
161 	DB_CMD("watchdog",	db_watchdog,		CS_OWN|DB_CMD_MEMSAFE),
162 	DB_CMD("thread",	db_set_thread,		0),
163 	DB_CMD("run",		db_run_cmd,		CS_OWN|DB_CMD_MEMSAFE),
164 	DB_CMD("script",	db_script_cmd,		CS_OWN|DB_CMD_MEMSAFE),
165 	DB_CMD("scripts",	db_scripts_cmd,		DB_CMD_MEMSAFE),
166 	DB_CMD("unscript",	db_unscript_cmd,	CS_OWN|DB_CMD_MEMSAFE),
167 	DB_CMD("capture",	db_capture_cmd,		CS_OWN|DB_CMD_MEMSAFE),
168 	DB_CMD("textdump",	db_textdump_cmd,	CS_OWN|DB_CMD_MEMSAFE),
169 	DB_CMD("findstack",	db_findstack_cmd,	0),
170 	DB_CMD("pprint",	db_pprint_cmd,		CS_OWN),
171 };
172 struct db_command_table db_cmd_table = LIST_HEAD_INITIALIZER(db_cmd_table);
173 
174 #undef DB_CMD
175 #undef DB_TABLE
176 
177 static struct db_command *db_last_command = NULL;
178 
179 /*
180  * if 'ed' style: 'dot' is set at start of last item printed,
181  * and '+' points to next line.
182  * Otherwise: 'dot' points to next item, '..' points to last.
183  */
184 static bool	db_ed_style = true;
185 
186 /*
187  * Utility routine - discard tokens through end-of-line.
188  */
189 void
190 db_skip_to_eol(void)
191 {
192 	int t;
193 
194 	do {
195 		t = db_read_token();
196 	} while (t != tEOL);
197 }
198 
199 /*
200  * Results of command search.
201  */
202 #define	CMD_UNIQUE	0
203 #define	CMD_FOUND	1
204 #define	CMD_NONE	2
205 #define	CMD_AMBIGUOUS	3
206 #define	CMD_HELP	4
207 
208 static void	db_cmd_match(char *name, struct db_command *cmd,
209 		    struct db_command **cmdp, int *resultp);
210 static void	db_cmd_list(struct db_command_table *table);
211 static int	db_cmd_search(char *name, struct db_command_table *table,
212 		    struct db_command **cmdp);
213 static void	db_command(struct db_command **last_cmdp,
214 		    struct db_command_table *cmd_table, bool dopager);
215 
216 /*
217  * Initialize the command lists from the static tables.
218  */
219 void
220 db_command_init(void)
221 {
222 	int i;
223 
224 	for (i = 0; i < nitems(db_cmds); i++)
225 		db_command_register(&db_cmd_table, &db_cmds[i]);
226 	for (i = 0; i < nitems(db_show_cmds); i++)
227 		db_command_register(&db_show_table, &db_show_cmds[i]);
228 	for (i = 0; i < nitems(db_show_active_cmds); i++)
229 		db_command_register(&db_show_active_table,
230 		    &db_show_active_cmds[i]);
231 	for (i = 0; i < nitems(db_show_all_cmds); i++)
232 		db_command_register(&db_show_all_table, &db_show_all_cmds[i]);
233 }
234 
235 /*
236  * Register a command.
237  */
238 void
239 db_command_register(struct db_command_table *list, struct db_command *cmd)
240 {
241 	struct db_command *c, *last;
242 
243 #ifdef MAC
244 	if (mac_ddb_command_register(list, cmd)) {
245 		printf("%s: MAC policy refused registration of command %s\n",
246 		    __func__, cmd->name);
247 		return;
248 	}
249 #endif
250 	last = NULL;
251 	LIST_FOREACH(c, list, next) {
252 		int n = strcmp(cmd->name, c->name);
253 
254 		/* Check that the command is not already present. */
255 		if (n == 0) {
256 			printf("%s: Warning, the command \"%s\" already exists;"
257 			     " ignoring request\n", __func__, cmd->name);
258 			return;
259 		}
260 		if (n < 0) {
261 			/* NB: keep list sorted lexicographically */
262 			LIST_INSERT_BEFORE(c, cmd, next);
263 			return;
264 		}
265 		last = c;
266 	}
267 	if (last == NULL)
268 		LIST_INSERT_HEAD(list, cmd, next);
269 	else
270 		LIST_INSERT_AFTER(last, cmd, next);
271 }
272 
273 /*
274  * Remove a command previously registered with db_command_register.
275  */
276 void
277 db_command_unregister(struct db_command_table *list, struct db_command *cmd)
278 {
279 	struct db_command *c;
280 
281 	LIST_FOREACH(c, list, next) {
282 		if (cmd == c) {
283 			LIST_REMOVE(cmd, next);
284 			return;
285 		}
286 	}
287 	/* NB: intentionally quiet */
288 }
289 
290 /*
291  * Helper function to match a single command.
292  */
293 static void
294 db_cmd_match(char *name, struct db_command *cmd, struct db_command **cmdp,
295     int *resultp)
296 {
297 	char *lp, *rp;
298 	int c;
299 
300 	lp = name;
301 	rp = cmd->name;
302 	while ((c = *lp) == *rp) {
303 		if (c == 0) {
304 			/* complete match */
305 			*cmdp = cmd;
306 			*resultp = CMD_UNIQUE;
307 			return;
308 		}
309 		lp++;
310 		rp++;
311 	}
312 	if (c == 0) {
313 		/* end of name, not end of command -
314 		   partial match */
315 		if (*resultp == CMD_FOUND) {
316 			*resultp = CMD_AMBIGUOUS;
317 			/* but keep looking for a full match -
318 			   this lets us match single letters */
319 		} else if (*resultp == CMD_NONE) {
320 			*cmdp = cmd;
321 			*resultp = CMD_FOUND;
322 		}
323 	}
324 }
325 
326 /*
327  * Search for command prefix.
328  */
329 static int
330 db_cmd_search(char *name, struct db_command_table *table,
331     struct db_command **cmdp)
332 {
333 	struct db_command *cmd;
334 	int result = CMD_NONE;
335 
336 	LIST_FOREACH(cmd, table, next) {
337 		db_cmd_match(name,cmd,cmdp,&result);
338 		if (result == CMD_UNIQUE)
339 			break;
340 	}
341 
342 	if (result == CMD_NONE) {
343 		/* check for 'help' */
344 		if (name[0] == 'h' && name[1] == 'e'
345 		    && name[2] == 'l' && name[3] == 'p')
346 			result = CMD_HELP;
347 	}
348 	return (result);
349 }
350 
351 static void
352 db_cmd_list(struct db_command_table *table)
353 {
354 	struct db_command *cmd;
355 	int have_subcommands;
356 
357 	have_subcommands = 0;
358 	LIST_FOREACH(cmd, table, next) {
359 		if (cmd->more != NULL)
360 			have_subcommands++;
361 		db_printf("%-16s", cmd->name);
362 		db_end_line(16);
363 	}
364 
365 	if (have_subcommands > 0) {
366 		db_printf("\nThe following have subcommands; append \"help\" "
367 		    "to list (e.g. \"show help\"):\n");
368 		LIST_FOREACH(cmd, table, next) {
369 			if (cmd->more == NULL)
370 				continue;
371 			db_printf("%-16s", cmd->name);
372 			db_end_line(16);
373 		}
374 	}
375 }
376 
377 static void
378 db_command(struct db_command **last_cmdp, struct db_command_table *cmd_table,
379     bool dopager)
380 {
381 	char modif[TOK_STRING_SIZE];
382 	struct db_command *cmd = NULL;
383 	db_expr_t addr, count;
384 	int t, result;
385 	bool have_addr = false;
386 
387 	t = db_read_token();
388 	if (t == tEOL) {
389 		/* empty line repeats last command, at 'next' */
390 		cmd = *last_cmdp;
391 		addr = (db_expr_t)db_next;
392 		have_addr = false;
393 		count = 1;
394 		modif[0] = '\0';
395 	} else if (t == tEXCL) {
396 		db_fncall((db_expr_t)0, false, (db_expr_t)0, NULL);
397 		return;
398 	} else if (t != tIDENT) {
399 		db_printf("Unrecognized input; use \"help\" "
400 	            "to list available commands\n");
401 		db_flush_lex();
402 		return;
403 	} else {
404 		/*
405 		 * Search for command
406 		 */
407 		while (cmd_table != NULL) {
408 			result = db_cmd_search(db_tok_string, cmd_table, &cmd);
409 			switch (result) {
410 			case CMD_NONE:
411 				db_printf("No such command; use \"help\" "
412 				    "to list available commands\n");
413 				db_flush_lex();
414 				return;
415 			case CMD_AMBIGUOUS:
416 				db_printf("Ambiguous\n");
417 				db_flush_lex();
418 				return;
419 			case CMD_HELP:
420 				if (cmd_table == &db_cmd_table) {
421 					db_printf("This is ddb(4), the kernel debugger; "
422 					    "see https://man.FreeBSD.org/ddb/4 for help.\n");
423 					db_printf("Use \"bt\" for backtrace, \"dump\" for "
424 					    "kernel core dump, \"reset\" to reboot.\n");
425 					db_printf("Available commands:\n");
426 				}
427 				db_cmd_list(cmd_table);
428 				db_flush_lex();
429 				return;
430 			case CMD_UNIQUE:
431 			case CMD_FOUND:
432 				break;
433 			}
434 			if ((cmd_table = cmd->more) != NULL) {
435 				t = db_read_token();
436 				if (t != tIDENT) {
437 					db_printf("Subcommand required; "
438 					    "available subcommands:\n");
439 					db_cmd_list(cmd_table);
440 					db_flush_lex();
441 					return;
442 				}
443 			}
444 		}
445 
446 		if ((cmd->flag & CS_OWN) == 0) {
447 			/*
448 			 * Standard syntax:
449 			 * command [/modifier] [addr] [,count]
450 			 */
451 			t = db_read_token();
452 			if (t == tSLASH) {
453 				t = db_read_token();
454 				if (t != tIDENT) {
455 					db_printf("Bad modifier\n");
456 					db_flush_lex();
457 					return;
458 				}
459 				db_strcpy(modif, db_tok_string);
460 			} else {
461 				db_unread_token(t);
462 				modif[0] = '\0';
463 			}
464 
465 			if (db_expression(&addr)) {
466 				db_dot = (db_addr_t) addr;
467 				db_last_addr = db_dot;
468 				have_addr = true;
469 			} else {
470 				addr = (db_expr_t) db_dot;
471 				have_addr = false;
472 			}
473 
474 			t = db_read_token();
475 			if (t == tCOMMA) {
476 				if (!db_expression(&count)) {
477 					db_printf("Count missing\n");
478 					db_flush_lex();
479 					return;
480 				}
481 			} else {
482 				db_unread_token(t);
483 				count = -1;
484 			}
485 
486 			if ((cmd->flag & CS_MORE) == 0) {
487 				db_skip_to_eol();
488 			}
489 		}
490 	}
491 
492 	*last_cmdp = cmd;
493 	if (cmd != NULL) {
494 #ifdef MAC
495 		if (mac_ddb_command_exec(cmd, addr, have_addr, count, modif)) {
496 			db_printf("MAC prevented execution of command %s\n",
497 			    cmd->name);
498 			return;
499 		}
500 #endif
501 		/*
502 		 * Execute the command.
503 		 */
504 		if (dopager)
505 			db_enable_pager();
506 		else
507 			db_disable_pager();
508 		(*cmd->fcn)(addr, have_addr, count, modif);
509 		if (dopager)
510 			db_disable_pager();
511 
512 		if (cmd->flag & CS_SET_DOT) {
513 			/*
514 			 * If command changes dot, set dot to previous address
515 			 * displayed (if 'ed' style).
516 			 */
517 			db_dot = db_ed_style ? db_prev : db_next;
518 		} else {
519 			/*
520 			 * If command does not change dot, set 'next' location
521 			 * to be the same.
522 			 */
523 			db_next = db_dot;
524 		}
525 	}
526 }
527 
528 /*
529  * At least one non-optional command must be implemented using
530  * DB_COMMAND() so that db_cmd_set gets created.  Here is one.
531  */
532 DB_COMMAND_FLAGS(panic, db_panic, DB_CMD_MEMSAFE)
533 {
534 	db_disable_pager();
535 	panic("from debugger");
536 }
537 
538 void
539 db_command_loop(void)
540 {
541 	/*
542 	 * Initialize 'prev' and 'next' to dot.
543 	 */
544 	db_prev = db_dot;
545 	db_next = db_dot;
546 
547 	db_cmd_loop_done = 0;
548 	while (!db_cmd_loop_done) {
549 		if (db_print_position() != 0)
550 			db_printf("\n");
551 
552 		db_printf("db> ");
553 		(void)db_read_line();
554 
555 		db_command(&db_last_command, &db_cmd_table, /* dopager */ true);
556 	}
557 }
558 
559 /*
560  * Execute a command on behalf of a script.  The caller is responsible for
561  * making sure that the command string is < DB_MAXLINE or it will be
562  * truncated.
563  *
564  * XXXRW: Runs by injecting faked input into DDB input stream; it would be
565  * nicer to use an alternative approach that didn't mess with the previous
566  * command buffer.
567  */
568 void
569 db_command_script(const char *command)
570 {
571 	db_prev = db_next = db_dot;
572 	db_inject_line(command);
573 	db_command(&db_last_command, &db_cmd_table, /* dopager */ false);
574 }
575 
576 void
577 db_error(const char *s)
578 {
579 	if (s)
580 	    db_printf("%s", s);
581 	db_flush_lex();
582 	kdb_reenter_silent();
583 }
584 
585 static void
586 db_dump(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
587 {
588 	int error;
589 
590 	if (textdump_pending) {
591 		db_printf("textdump_pending set.\n"
592 		    "run \"textdump unset\" first or \"textdump dump\" for a textdump.\n");
593 		return;
594 	}
595 	error = doadump(false);
596 	if (error) {
597 		db_printf("Cannot dump: ");
598 		switch (error) {
599 		case EBUSY:
600 			db_printf("debugger got invoked while dumping.\n");
601 			break;
602 		case ENXIO:
603 			db_printf("no dump device specified.\n");
604 			break;
605 		default:
606 			db_printf("unknown error (error=%d).\n", error);
607 			break;
608 		}
609 	}
610 }
611 
612 /*
613  * Call random function:
614  * !expr(arg,arg,arg)
615  */
616 
617 /* The generic implementation supports a maximum of 10 arguments. */
618 typedef db_expr_t __db_f(db_expr_t, db_expr_t, db_expr_t, db_expr_t,
619     db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t);
620 
621 static __inline int
622 db_fncall_generic(db_expr_t addr, db_expr_t *rv, int nargs, db_expr_t args[])
623 {
624 	__db_f *f = (__db_f *)addr;
625 
626 	if (nargs > 10) {
627 		db_printf("Too many arguments (max 10)\n");
628 		return (0);
629 	}
630 	*rv = (*f)(args[0], args[1], args[2], args[3], args[4], args[5],
631 	    args[6], args[7], args[8], args[9]);
632 	return (1);
633 }
634 
635 static void
636 db_fncall(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
637 {
638 	db_expr_t	fn_addr;
639 	db_expr_t	args[DB_MAXARGS];
640 	int		nargs = 0;
641 	db_expr_t	retval;
642 	int		t;
643 
644 	if (!db_expression(&fn_addr)) {
645 	    db_printf("Bad function\n");
646 	    db_flush_lex();
647 	    return;
648 	}
649 
650 	t = db_read_token();
651 	if (t == tLPAREN) {
652 	    if (db_expression(&args[0])) {
653 		nargs++;
654 		while ((t = db_read_token()) == tCOMMA) {
655 		    if (nargs == DB_MAXARGS) {
656 			db_printf("Too many arguments (max %d)\n", DB_MAXARGS);
657 			db_flush_lex();
658 			return;
659 		    }
660 		    if (!db_expression(&args[nargs])) {
661 			db_printf("Argument missing\n");
662 			db_flush_lex();
663 			return;
664 		    }
665 		    nargs++;
666 		}
667 		db_unread_token(t);
668 	    }
669 	    if (db_read_token() != tRPAREN) {
670 	        db_printf("Mismatched parens\n");
671 		db_flush_lex();
672 		return;
673 	    }
674 	}
675 	db_skip_to_eol();
676 	db_disable_pager();
677 
678 	if (DB_CALL(fn_addr, &retval, nargs, args))
679 		db_printf("= %#lr\n", (long)retval);
680 }
681 
682 static void
683 db_halt(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
684 {
685 
686 	cpu_halt();
687 }
688 
689 static void
690 db_kill(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
691 {
692 	db_expr_t old_radix, pid, sig;
693 	struct proc *p;
694 
695 #define	DB_ERROR(f)	do { db_printf f; db_flush_lex(); goto out; } while (0)
696 
697 	/*
698 	 * PIDs and signal numbers are typically represented in base
699 	 * 10, so make that the default here.  It can, of course, be
700 	 * overridden by specifying a prefix.
701 	 */
702 	old_radix = db_radix;
703 	db_radix = 10;
704 	/* Retrieve arguments. */
705 	if (!db_expression(&sig))
706 		DB_ERROR(("Missing signal number\n"));
707 	if (!db_expression(&pid))
708 		DB_ERROR(("Missing process ID\n"));
709 	db_skip_to_eol();
710 	if (!_SIG_VALID(sig))
711 		DB_ERROR(("Signal number out of range\n"));
712 
713 	/*
714 	 * Find the process in question.  allproc_lock is not needed
715 	 * since we're in DDB.
716 	 */
717 	/* sx_slock(&allproc_lock); */
718 	FOREACH_PROC_IN_SYSTEM(p)
719 	    if (p->p_pid == pid)
720 		    break;
721 	/* sx_sunlock(&allproc_lock); */
722 	if (p == NULL)
723 		DB_ERROR(("Can't find process with pid %ld\n", (long) pid));
724 
725 	/* If it's already locked, bail; otherwise, do the deed. */
726 	if (PROC_TRYLOCK(p) == 0)
727 		DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
728 	else {
729 		pksignal(p, sig, NULL);
730 		PROC_UNLOCK(p);
731 	}
732 
733 out:
734 	db_radix = old_radix;
735 #undef DB_ERROR
736 }
737 
738 /*
739  * Reboot.  In case there is an additional argument, take it as delay in
740  * seconds.  Default to 15s if we cannot parse it and make sure we will
741  * never wait longer than 1 week.  Some code is similar to
742  * kern_shutdown.c:shutdown_panic().
743  */
744 #ifndef	DB_RESET_MAXDELAY
745 #define	DB_RESET_MAXDELAY	(3600 * 24 * 7)
746 #endif
747 
748 static void
749 db_reset(db_expr_t addr, bool have_addr, db_expr_t count __unused,
750     char *modif)
751 {
752 	int delay, loop;
753 
754 	if (have_addr) {
755 		delay = (int)db_hex2dec(addr);
756 
757 		/* If we parse to fail, use 15s. */
758 		if (delay == -1)
759 			delay = 15;
760 
761 		/* Cap at one week. */
762 		if ((uintmax_t)delay > (uintmax_t)DB_RESET_MAXDELAY)
763 			delay = DB_RESET_MAXDELAY;
764 
765 		db_printf("Automatic reboot in %d seconds - "
766 		    "press a key on the console to abort\n", delay);
767 		for (loop = delay * 10; loop > 0; --loop) {
768 			DELAY(1000 * 100); /* 1/10th second */
769 			/* Did user type a key? */
770 			if (cncheckc() != -1)
771 				return;
772 		}
773 	}
774 
775 	/*
776 	 * Conditionally try the standard reboot path, so any registered
777 	 * shutdown/reset handlers have a chance to run first. Some platforms
778 	 * may not support the machine-dependent mechanism used by cpu_reset()
779 	 * and rely on some other non-standard mechanism to perform the reset.
780 	 * For example, the BCM2835 watchdog driver or gpio-poweroff driver.
781 	 */
782 	if (modif[0] != 's') {
783 		kern_reboot(RB_NOSYNC);
784 		/* NOTREACHED */
785 	}
786 
787 	cpu_reset();
788 }
789 
790 static void
791 db_watchdog(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
792 {
793 	db_expr_t old_radix, tout;
794 	int err, i;
795 
796 	old_radix = db_radix;
797 	db_radix = 10;
798 	err = db_expression(&tout);
799 	db_skip_to_eol();
800 	db_radix = old_radix;
801 
802 	/* If no argument is provided the watchdog will just be disabled. */
803 	if (err == 0) {
804 		db_printf("No argument provided, disabling watchdog\n");
805 		tout = 0;
806 	} else if ((tout & WD_INTERVAL) == WD_TO_NEVER) {
807 		db_error("Out of range watchdog interval\n");
808 		return;
809 	}
810 	EVENTHANDLER_INVOKE(watchdog_list, tout, &i);
811 }
812 
813 static void
814 db_gdb(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
815 {
816 
817 	if (kdb_dbbe_select("gdb") != 0) {
818 		db_printf("The remote GDB backend could not be selected.\n");
819 		return;
820 	}
821 	/*
822 	 * Mark that we are done in the debugger.  kdb_trap()
823 	 * should re-enter with the new backend.
824 	 */
825 	db_cmd_loop_done = 1;
826 	db_printf("(ctrl-c will return control to ddb)\n");
827 }
828 
829 static void
830 db_stack_trace(db_expr_t tid, bool hastid, db_expr_t count, char *modif)
831 {
832 	struct thread *td;
833 	db_expr_t radix;
834 	pid_t pid;
835 	int t;
836 
837 	/*
838 	 * We parse our own arguments. We don't like the default radix.
839 	 */
840 	radix = db_radix;
841 	db_radix = 10;
842 	hastid = db_expression(&tid);
843 	t = db_read_token();
844 	if (t == tCOMMA) {
845 		if (!db_expression(&count)) {
846 			db_printf("Count missing\n");
847 			db_flush_lex();
848 			db_radix = radix;
849 			return;
850 		}
851 	} else {
852 		db_unread_token(t);
853 		count = -1;
854 	}
855 	db_skip_to_eol();
856 	db_radix = radix;
857 
858 	if (hastid) {
859 		td = kdb_thr_lookup((lwpid_t)tid);
860 		if (td == NULL)
861 			td = kdb_thr_from_pid((pid_t)tid);
862 		if (td == NULL) {
863 			db_printf("Thread %d not found\n", (int)tid);
864 			return;
865 		}
866 	} else
867 		td = kdb_thread;
868 	if (td->td_proc != NULL)
869 		pid = td->td_proc->p_pid;
870 	else
871 		pid = -1;
872 	db_printf("Tracing pid %d tid %ld td %p\n", pid, (long)td->td_tid, td);
873 	if (td->td_proc != NULL && (td->td_proc->p_flag & P_INMEM) == 0)
874 		db_printf("--- swapped out\n");
875 	else
876 		db_trace_thread(td, count);
877 }
878 
879 static void
880 _db_stack_trace_all(bool active_only)
881 {
882 	struct thread *td;
883 	jmp_buf jb;
884 	void *prev_jb;
885 
886 	for (td = kdb_thr_first(); td != NULL; td = kdb_thr_next(td)) {
887 		prev_jb = kdb_jmpbuf(jb);
888 		if (setjmp(jb) == 0) {
889 			if (TD_IS_RUNNING(td))
890 				db_printf("\nTracing command %s pid %d"
891 				    " tid %ld td %p (CPU %d)\n",
892 				    td->td_proc->p_comm, td->td_proc->p_pid,
893 				    (long)td->td_tid, td, td->td_oncpu);
894 			else if (active_only)
895 				continue;
896 			else
897 				db_printf("\nTracing command %s pid %d"
898 				    " tid %ld td %p\n", td->td_proc->p_comm,
899 				    td->td_proc->p_pid, (long)td->td_tid, td);
900 			if (td->td_proc->p_flag & P_INMEM)
901 				db_trace_thread(td, -1);
902 			else
903 				db_printf("--- swapped out\n");
904 			if (db_pager_quit) {
905 				kdb_jmpbuf(prev_jb);
906 				return;
907 			}
908 		}
909 		kdb_jmpbuf(prev_jb);
910 	}
911 }
912 
913 static void
914 db_stack_trace_active(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
915     char *dummy4)
916 {
917 
918 	_db_stack_trace_all(true);
919 }
920 
921 static void
922 db_stack_trace_all(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
923     char *dummy4)
924 {
925 
926 	_db_stack_trace_all(false);
927 }
928 
929 /*
930  * Take the parsed expression value from the command line that was parsed
931  * as a hexadecimal value and convert it as if the expression was parsed
932  * as a decimal value.  Returns -1 if the expression was not a valid
933  * decimal value.
934  */
935 db_expr_t
936 db_hex2dec(db_expr_t expr)
937 {
938 	uintptr_t x, y;
939 	db_expr_t val;
940 
941 	y = 1;
942 	val = 0;
943 	x = expr;
944 	while (x != 0) {
945 		if (x % 16 > 9)
946 			return (-1);
947 		val += (x % 16) * (y);
948 		x >>= 4;
949 		y *= 10;
950 	}
951 	return (val);
952 }
953