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