xref: /freebsd/sys/ddb/db_command.c (revision e9ac41698b2f322d55ccf9da50a3596edb2c1800)
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 	panic("%s: did not reenter debugger", __func__);
584 }
585 
586 static void
587 db_dump(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
588 {
589 	int error;
590 
591 	if (textdump_pending) {
592 		db_printf("textdump_pending set.\n"
593 		    "run \"textdump unset\" first or \"textdump dump\" for a textdump.\n");
594 		return;
595 	}
596 	error = doadump(false);
597 	if (error) {
598 		db_printf("Cannot dump: ");
599 		switch (error) {
600 		case EBUSY:
601 			db_printf("debugger got invoked while dumping.\n");
602 			break;
603 		case ENXIO:
604 			db_printf("no dump device specified.\n");
605 			break;
606 		default:
607 			db_printf("unknown error (error=%d).\n", error);
608 			break;
609 		}
610 	}
611 }
612 
613 /*
614  * Call random function:
615  * !expr(arg,arg,arg)
616  */
617 
618 /* The generic implementation supports a maximum of 10 arguments. */
619 typedef db_expr_t __db_f(db_expr_t, db_expr_t, db_expr_t, db_expr_t,
620     db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t);
621 
622 static __inline int
623 db_fncall_generic(db_expr_t addr, db_expr_t *rv, int nargs, db_expr_t args[])
624 {
625 	__db_f *f = (__db_f *)addr;
626 
627 	if (nargs > 10) {
628 		db_printf("Too many arguments (max 10)\n");
629 		return (0);
630 	}
631 	*rv = (*f)(args[0], args[1], args[2], args[3], args[4], args[5],
632 	    args[6], args[7], args[8], args[9]);
633 	return (1);
634 }
635 
636 static void
637 db_fncall(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
638 {
639 	db_expr_t	fn_addr;
640 	db_expr_t	args[DB_MAXARGS];
641 	int		nargs = 0;
642 	db_expr_t	retval;
643 	int		t;
644 
645 	if (!db_expression(&fn_addr)) {
646 	    db_printf("Bad function\n");
647 	    db_flush_lex();
648 	    return;
649 	}
650 
651 	t = db_read_token();
652 	if (t == tLPAREN) {
653 	    if (db_expression(&args[0])) {
654 		nargs++;
655 		while ((t = db_read_token()) == tCOMMA) {
656 		    if (nargs == DB_MAXARGS) {
657 			db_printf("Too many arguments (max %d)\n", DB_MAXARGS);
658 			db_flush_lex();
659 			return;
660 		    }
661 		    if (!db_expression(&args[nargs])) {
662 			db_printf("Argument missing\n");
663 			db_flush_lex();
664 			return;
665 		    }
666 		    nargs++;
667 		}
668 		db_unread_token(t);
669 	    }
670 	    if (db_read_token() != tRPAREN) {
671 	        db_printf("Mismatched parens\n");
672 		db_flush_lex();
673 		return;
674 	    }
675 	}
676 	db_skip_to_eol();
677 	db_disable_pager();
678 
679 	if (DB_CALL(fn_addr, &retval, nargs, args))
680 		db_printf("= %#lr\n", (long)retval);
681 }
682 
683 static void
684 db_halt(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
685 {
686 
687 	cpu_halt();
688 }
689 
690 static void
691 db_kill(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
692 {
693 	db_expr_t old_radix, pid, sig;
694 	struct proc *p;
695 
696 #define	DB_ERROR(f)	do { db_printf f; db_flush_lex(); goto out; } while (0)
697 
698 	/*
699 	 * PIDs and signal numbers are typically represented in base
700 	 * 10, so make that the default here.  It can, of course, be
701 	 * overridden by specifying a prefix.
702 	 */
703 	old_radix = db_radix;
704 	db_radix = 10;
705 	/* Retrieve arguments. */
706 	if (!db_expression(&sig))
707 		DB_ERROR(("Missing signal number\n"));
708 	if (!db_expression(&pid))
709 		DB_ERROR(("Missing process ID\n"));
710 	db_skip_to_eol();
711 	if (!_SIG_VALID(sig))
712 		DB_ERROR(("Signal number out of range\n"));
713 
714 	/*
715 	 * Find the process in question.  allproc_lock is not needed
716 	 * since we're in DDB.
717 	 */
718 	/* sx_slock(&allproc_lock); */
719 	FOREACH_PROC_IN_SYSTEM(p)
720 	    if (p->p_pid == pid)
721 		    break;
722 	/* sx_sunlock(&allproc_lock); */
723 	if (p == NULL)
724 		DB_ERROR(("Can't find process with pid %ld\n", (long) pid));
725 
726 	/* If it's already locked, bail; otherwise, do the deed. */
727 	if (PROC_TRYLOCK(p) == 0)
728 		DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
729 	else {
730 		pksignal(p, sig, NULL);
731 		PROC_UNLOCK(p);
732 	}
733 
734 out:
735 	db_radix = old_radix;
736 #undef DB_ERROR
737 }
738 
739 /*
740  * Reboot.  In case there is an additional argument, take it as delay in
741  * seconds.  Default to 15s if we cannot parse it and make sure we will
742  * never wait longer than 1 week.  Some code is similar to
743  * kern_shutdown.c:shutdown_panic().
744  */
745 #ifndef	DB_RESET_MAXDELAY
746 #define	DB_RESET_MAXDELAY	(3600 * 24 * 7)
747 #endif
748 
749 static void
750 db_reset(db_expr_t addr, bool have_addr, db_expr_t count __unused,
751     char *modif)
752 {
753 	int delay, loop;
754 
755 	if (have_addr) {
756 		delay = (int)db_hex2dec(addr);
757 
758 		/* If we parse to fail, use 15s. */
759 		if (delay == -1)
760 			delay = 15;
761 
762 		/* Cap at one week. */
763 		if ((uintmax_t)delay > (uintmax_t)DB_RESET_MAXDELAY)
764 			delay = DB_RESET_MAXDELAY;
765 
766 		db_printf("Automatic reboot in %d seconds - "
767 		    "press a key on the console to abort\n", delay);
768 		for (loop = delay * 10; loop > 0; --loop) {
769 			DELAY(1000 * 100); /* 1/10th second */
770 			/* Did user type a key? */
771 			if (cncheckc() != -1)
772 				return;
773 		}
774 	}
775 
776 	/*
777 	 * Conditionally try the standard reboot path, so any registered
778 	 * shutdown/reset handlers have a chance to run first. Some platforms
779 	 * may not support the machine-dependent mechanism used by cpu_reset()
780 	 * and rely on some other non-standard mechanism to perform the reset.
781 	 * For example, the BCM2835 watchdog driver or gpio-poweroff driver.
782 	 */
783 	if (modif[0] != 's') {
784 		kern_reboot(RB_NOSYNC);
785 		/* NOTREACHED */
786 	}
787 
788 	cpu_reset();
789 }
790 
791 static void
792 db_watchdog(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
793 {
794 	db_expr_t old_radix, tout;
795 	int err, i;
796 
797 	old_radix = db_radix;
798 	db_radix = 10;
799 	err = db_expression(&tout);
800 	db_skip_to_eol();
801 	db_radix = old_radix;
802 
803 	/* If no argument is provided the watchdog will just be disabled. */
804 	if (err == 0) {
805 		db_printf("No argument provided, disabling watchdog\n");
806 		tout = 0;
807 	} else if ((tout & WD_INTERVAL) == WD_TO_NEVER) {
808 		db_error("Out of range watchdog interval\n");
809 		return;
810 	}
811 	EVENTHANDLER_INVOKE(watchdog_list, tout, &i);
812 }
813 
814 static void
815 db_gdb(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
816 {
817 
818 	if (kdb_dbbe_select("gdb") != 0) {
819 		db_printf("The remote GDB backend could not be selected.\n");
820 		return;
821 	}
822 	/*
823 	 * Mark that we are done in the debugger.  kdb_trap()
824 	 * should re-enter with the new backend.
825 	 */
826 	db_cmd_loop_done = 1;
827 	db_printf("(ctrl-c will return control to ddb)\n");
828 }
829 
830 static void
831 db_stack_trace(db_expr_t tid, bool hastid, db_expr_t count, char *modif)
832 {
833 	struct thread *td;
834 	db_expr_t radix;
835 	pid_t pid;
836 	int t;
837 
838 	/*
839 	 * We parse our own arguments. We don't like the default radix.
840 	 */
841 	radix = db_radix;
842 	db_radix = 10;
843 	hastid = db_expression(&tid);
844 	t = db_read_token();
845 	if (t == tCOMMA) {
846 		if (!db_expression(&count)) {
847 			db_printf("Count missing\n");
848 			db_flush_lex();
849 			db_radix = radix;
850 			return;
851 		}
852 	} else {
853 		db_unread_token(t);
854 		count = -1;
855 	}
856 	db_skip_to_eol();
857 	db_radix = radix;
858 
859 	if (hastid) {
860 		td = kdb_thr_lookup((lwpid_t)tid);
861 		if (td == NULL)
862 			td = kdb_thr_from_pid((pid_t)tid);
863 		if (td == NULL) {
864 			db_printf("Thread %d not found\n", (int)tid);
865 			return;
866 		}
867 	} else
868 		td = kdb_thread;
869 	if (td->td_proc != NULL)
870 		pid = td->td_proc->p_pid;
871 	else
872 		pid = -1;
873 	db_printf("Tracing pid %d tid %ld td %p\n", pid, (long)td->td_tid, td);
874 	if (td->td_proc != NULL && (td->td_proc->p_flag & P_INMEM) == 0)
875 		db_printf("--- swapped out\n");
876 	else
877 		db_trace_thread(td, count);
878 }
879 
880 static void
881 _db_stack_trace_all(bool active_only)
882 {
883 	struct thread *td;
884 	jmp_buf jb;
885 	void *prev_jb;
886 
887 	for (td = kdb_thr_first(); td != NULL; td = kdb_thr_next(td)) {
888 		prev_jb = kdb_jmpbuf(jb);
889 		if (setjmp(jb) == 0) {
890 			if (TD_IS_RUNNING(td))
891 				db_printf("\nTracing command %s pid %d"
892 				    " tid %ld td %p (CPU %d)\n",
893 				    td->td_proc->p_comm, td->td_proc->p_pid,
894 				    (long)td->td_tid, td, td->td_oncpu);
895 			else if (active_only)
896 				continue;
897 			else
898 				db_printf("\nTracing command %s pid %d"
899 				    " tid %ld td %p\n", td->td_proc->p_comm,
900 				    td->td_proc->p_pid, (long)td->td_tid, td);
901 			if (td->td_proc->p_flag & P_INMEM)
902 				db_trace_thread(td, -1);
903 			else
904 				db_printf("--- swapped out\n");
905 			if (db_pager_quit) {
906 				kdb_jmpbuf(prev_jb);
907 				return;
908 			}
909 		}
910 		kdb_jmpbuf(prev_jb);
911 	}
912 }
913 
914 static void
915 db_stack_trace_active(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
916     char *dummy4)
917 {
918 
919 	_db_stack_trace_all(true);
920 }
921 
922 static void
923 db_stack_trace_all(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
924     char *dummy4)
925 {
926 
927 	_db_stack_trace_all(false);
928 }
929 
930 /*
931  * Take the parsed expression value from the command line that was parsed
932  * as a hexadecimal value and convert it as if the expression was parsed
933  * as a decimal value.  Returns -1 if the expression was not a valid
934  * decimal value.
935  */
936 db_expr_t
937 db_hex2dec(db_expr_t expr)
938 {
939 	uintptr_t x, y;
940 	db_expr_t val;
941 
942 	y = 1;
943 	val = 0;
944 	x = expr;
945 	while (x != 0) {
946 		if (x % 16 > 9)
947 			return (-1);
948 		val += (x % 16) * (y);
949 		x >>= 4;
950 		y *= 10;
951 	}
952 	return (val);
953 }
954