sys/ddb/db_command.c

   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/cdefs.h>
  37 #include <sys/param.h>
  38 #include <sys/conf.h>
  39 #include <sys/cons.h>
  40 #include <sys/eventhandler.h>
  41 #include <sys/kdb.h>
  42 #include <sys/kernel.h>
  43 #include <sys/linker_set.h>
  44 #include <sys/lock.h>
  45 #include <sys/mutex.h>
  46 #include <sys/proc.h>
  47 #include <sys/reboot.h>
  48 #include <sys/signalvar.h>
  49 #include <sys/systm.h>
  50 #include <sys/watchdog.h>
  51
  52 #include <ddb/ddb.h>
  53 #include <ddb/db_command.h>
  54 #include <ddb/db_lex.h>
  55 #include <ddb/db_output.h>
  56
  57 #include <machine/cpu.h>
  58 #include <machine/setjmp.h>
  59
  60 #include <security/mac/mac_framework.h>
  61
  62 /*
  63  * Exported global variables
  64  */
  65 int             db_cmd_loop_done;
  66 db_addr_t       db_dot;
  67 db_addr_t       db_last_addr;
  68 db_addr_t       db_prev;
  69 db_addr_t       db_next;
  70
  71 static db_cmdfcn_t      db_dump;
  72 static db_cmdfcn_t      db_fncall;
  73 static db_cmdfcn_t      db_gdb;
  74 static db_cmdfcn_t      db_halt;
  75 static db_cmdfcn_t      db_kill;
  76 static db_cmdfcn_t      db_reset;
  77 static db_cmdfcn_t      db_stack_trace;
  78 static db_cmdfcn_t      db_stack_trace_active;
  79 static db_cmdfcn_t      db_stack_trace_all;
  80 static db_cmdfcn_t      db_watchdog;
  81
  82 #define DB_CMD(_name, _func, _flags)    \
  83 {                                       \
  84         .name = (_name),                \
  85         .fcn =  (_func),                \
  86         .flag = (_flags),               \
  87         .more = NULL,                   \
  88 }
  89 #define DB_TABLE(_name, _more)          \
  90 {                                       \
  91         .name = (_name),                \
  92         .fcn =  NULL,                   \
  93         .more = (_more),                \
  94 }
  95
  96 static struct db_command db_show_active_cmds[] = {
  97         DB_CMD("trace",         db_stack_trace_active,  DB_CMD_MEMSAFE),
  98 };
  99 struct db_command_table db_show_active_table =
 100     LIST_HEAD_INITIALIZER(db_show_active_table);
 101
 102 static struct db_command db_show_all_cmds[] = {
 103         DB_CMD("trace",         db_stack_trace_all,     DB_CMD_MEMSAFE),
 104 };
 105 struct db_command_table db_show_all_table =
 106     LIST_HEAD_INITIALIZER(db_show_all_table);
 107
 108 static struct db_command db_show_cmds[] = {
 109         DB_TABLE("active",      &db_show_active_table),
 110         DB_TABLE("all",         &db_show_all_table),
 111         DB_CMD("registers",     db_show_regs,           DB_CMD_MEMSAFE),
 112         DB_CMD("breaks",        db_listbreak_cmd,       DB_CMD_MEMSAFE),
 113         DB_CMD("threads",       db_show_threads,        DB_CMD_MEMSAFE),
 114 };
 115 struct db_command_table db_show_table = LIST_HEAD_INITIALIZER(db_show_table);
 116
 117 static struct db_command db_cmds[] = {
 118         DB_TABLE("show",        &db_show_table),
 119         DB_CMD("print",         db_print_cmd,           0),
 120         DB_CMD("p",             db_print_cmd,           0),
 121         DB_CMD("examine",       db_examine_cmd,         CS_SET_DOT),
 122         DB_CMD("x",             db_examine_cmd,         CS_SET_DOT),
 123         DB_CMD("search",        db_search_cmd,          CS_OWN|CS_SET_DOT),
 124         DB_CMD("set",           db_set_cmd,             CS_OWN|DB_CMD_MEMSAFE),
 125         DB_CMD("write",         db_write_cmd,           CS_MORE|CS_SET_DOT),
 126         DB_CMD("w",             db_write_cmd,           CS_MORE|CS_SET_DOT),
 127         DB_CMD("delete",        db_delete_cmd,          0),
 128         DB_CMD("d",             db_delete_cmd,          0),
 129         DB_CMD("dump",          db_dump,                DB_CMD_MEMSAFE),
 130         DB_CMD("break",         db_breakpoint_cmd,      0),
 131         DB_CMD("b",             db_breakpoint_cmd,      0),
 132         DB_CMD("dwatch",        db_deletewatch_cmd,     0),
 133         DB_CMD("watch",         db_watchpoint_cmd,      CS_MORE),
 134         DB_CMD("dhwatch",       db_deletehwatch_cmd,    0),
 135         DB_CMD("hwatch",        db_hwatchpoint_cmd,     0),
 136         DB_CMD("step",          db_single_step_cmd,     DB_CMD_MEMSAFE),
 137         DB_CMD("s",             db_single_step_cmd,     DB_CMD_MEMSAFE),
 138         DB_CMD("continue",      db_continue_cmd,        DB_CMD_MEMSAFE),
 139         DB_CMD("c",             db_continue_cmd,        DB_CMD_MEMSAFE),
 140         DB_CMD("until",         db_trace_until_call_cmd, DB_CMD_MEMSAFE),
 141         DB_CMD("next",          db_trace_until_matching_cmd, DB_CMD_MEMSAFE),
 142         DB_CMD("match",         db_trace_until_matching_cmd, 0),
 143         DB_CMD("trace",         db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 144         DB_CMD("t",             db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 145         /* XXX alias for active trace */
 146         DB_CMD("acttrace",      db_stack_trace_active,  DB_CMD_MEMSAFE),
 147         /* XXX alias for all trace */
 148         DB_CMD("alltrace",      db_stack_trace_all,     DB_CMD_MEMSAFE),
 149         DB_CMD("where",         db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 150         DB_CMD("bt",            db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 151         DB_CMD("call",          db_fncall,              CS_OWN),
 152         DB_CMD("ps",            db_ps,                  DB_CMD_MEMSAFE),
 153         DB_CMD("gdb",           db_gdb,                 0),
 154         DB_CMD("halt",          db_halt,                DB_CMD_MEMSAFE),
 155         DB_CMD("reboot",        db_reset,               DB_CMD_MEMSAFE),
 156         DB_CMD("reset",         db_reset,               DB_CMD_MEMSAFE),
 157         DB_CMD("kill",          db_kill,                CS_OWN|DB_CMD_MEMSAFE),
 158         DB_CMD("watchdog",      db_watchdog,            CS_OWN|DB_CMD_MEMSAFE),
 159         DB_CMD("thread",        db_set_thread,          0),
 160         DB_CMD("run",           db_run_cmd,             CS_OWN|DB_CMD_MEMSAFE),
 161         DB_CMD("script",        db_script_cmd,          CS_OWN|DB_CMD_MEMSAFE),
 162         DB_CMD("scripts",       db_scripts_cmd,         DB_CMD_MEMSAFE),
 163         DB_CMD("unscript",      db_unscript_cmd,        CS_OWN|DB_CMD_MEMSAFE),
 164         DB_CMD("capture",       db_capture_cmd,         CS_OWN|DB_CMD_MEMSAFE),
 165         DB_CMD("textdump",      db_textdump_cmd,        CS_OWN|DB_CMD_MEMSAFE),
 166         DB_CMD("findstack",     db_findstack_cmd,       0),
 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 }