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 __FBSDID("$FreeBSD$");
  38
  39 #include <sys/param.h>
  40 #include <sys/conf.h>
  41 #include <sys/cons.h>
  42 #include <sys/eventhandler.h>
  43 #include <sys/kdb.h>
  44 #include <sys/kernel.h>
  45 #include <sys/linker_set.h>
  46 #include <sys/lock.h>
  47 #include <sys/mutex.h>
  48 #include <sys/proc.h>
  49 #include <sys/reboot.h>
  50 #include <sys/signalvar.h>
  51 #include <sys/systm.h>
  52 #include <sys/watchdog.h>
  53
  54 #include <ddb/ddb.h>
  55 #include <ddb/db_command.h>
  56 #include <ddb/db_lex.h>
  57 #include <ddb/db_output.h>
  58
  59 #include <machine/cpu.h>
  60 #include <machine/setjmp.h>
  61
  62 #include <security/mac/mac_framework.h>
  63
  64 /*
  65  * Exported global variables
  66  */
  67 int             db_cmd_loop_done;
  68 db_addr_t       db_dot;
  69 db_addr_t       db_last_addr;
  70 db_addr_t       db_prev;
  71 db_addr_t       db_next;
  72
  73 static db_cmdfcn_t      db_dump;
  74 static db_cmdfcn_t      db_fncall;
  75 static db_cmdfcn_t      db_gdb;
  76 static db_cmdfcn_t      db_halt;
  77 static db_cmdfcn_t      db_kill;
  78 static db_cmdfcn_t      db_reset;
  79 static db_cmdfcn_t      db_stack_trace;
  80 static db_cmdfcn_t      db_stack_trace_active;
  81 static db_cmdfcn_t      db_stack_trace_all;
  82 static db_cmdfcn_t      db_watchdog;
  83
  84 #define DB_CMD(_name, _func, _flags)    \
  85 {                                       \
  86         .name = (_name),                \
  87         .fcn =  (_func),                \
  88         .flag = (_flags),               \
  89         .more = NULL,                   \
  90 }
  91 #define DB_TABLE(_name, _more)          \
  92 {                                       \
  93         .name = (_name),                \
  94         .fcn =  NULL,                   \
  95         .more = (_more),                \
  96 }
  97
  98 static struct db_command db_show_active_cmds[] = {
  99         DB_CMD("trace",         db_stack_trace_active,  DB_CMD_MEMSAFE),
 100 };
 101 struct db_command_table db_show_active_table =
 102     LIST_HEAD_INITIALIZER(db_show_active_table);
 103
 104 static struct db_command db_show_all_cmds[] = {
 105         DB_CMD("trace",         db_stack_trace_all,     DB_CMD_MEMSAFE),
 106 };
 107 struct db_command_table db_show_all_table =
 108     LIST_HEAD_INITIALIZER(db_show_all_table);
 109
 110 static struct db_command db_show_cmds[] = {
 111         DB_TABLE("active",      &db_show_active_table),
 112         DB_TABLE("all",         &db_show_all_table),
 113         DB_CMD("registers",     db_show_regs,           DB_CMD_MEMSAFE),
 114         DB_CMD("breaks",        db_listbreak_cmd,       DB_CMD_MEMSAFE),
 115         DB_CMD("threads",       db_show_threads,        DB_CMD_MEMSAFE),
 116 };
 117 struct db_command_table db_show_table = LIST_HEAD_INITIALIZER(db_show_table);
 118
 119 static struct db_command db_cmds[] = {
 120         DB_TABLE("show",        &db_show_table),
 121         DB_CMD("print",         db_print_cmd,           0),
 122         DB_CMD("p",             db_print_cmd,           0),
 123         DB_CMD("examine",       db_examine_cmd,         CS_SET_DOT),
 124         DB_CMD("x",             db_examine_cmd,         CS_SET_DOT),
 125         DB_CMD("search",        db_search_cmd,          CS_OWN|CS_SET_DOT),
 126         DB_CMD("set",           db_set_cmd,             CS_OWN|DB_CMD_MEMSAFE),
 127         DB_CMD("write",         db_write_cmd,           CS_MORE|CS_SET_DOT),
 128         DB_CMD("w",             db_write_cmd,           CS_MORE|CS_SET_DOT),
 129         DB_CMD("delete",        db_delete_cmd,          0),
 130         DB_CMD("d",             db_delete_cmd,          0),
 131         DB_CMD("dump",          db_dump,                DB_CMD_MEMSAFE),
 132         DB_CMD("break",         db_breakpoint_cmd,      0),
 133         DB_CMD("b",             db_breakpoint_cmd,      0),
 134         DB_CMD("dwatch",        db_deletewatch_cmd,     0),
 135         DB_CMD("watch",         db_watchpoint_cmd,      CS_MORE),
 136         DB_CMD("dhwatch",       db_deletehwatch_cmd,    0),
 137         DB_CMD("hwatch",        db_hwatchpoint_cmd,     0),
 138         DB_CMD("step",          db_single_step_cmd,     DB_CMD_MEMSAFE),
 139         DB_CMD("s",             db_single_step_cmd,     DB_CMD_MEMSAFE),
 140         DB_CMD("continue",      db_continue_cmd,        DB_CMD_MEMSAFE),
 141         DB_CMD("c",             db_continue_cmd,        DB_CMD_MEMSAFE),
 142         DB_CMD("until",         db_trace_until_call_cmd, DB_CMD_MEMSAFE),
 143         DB_CMD("next",          db_trace_until_matching_cmd, DB_CMD_MEMSAFE),
 144         DB_CMD("match",         db_trace_until_matching_cmd, 0),
 145         DB_CMD("trace",         db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 146         DB_CMD("t",             db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 147         /* XXX alias for active trace */
 148         DB_CMD("acttrace",      db_stack_trace_active,  DB_CMD_MEMSAFE),
 149         /* XXX alias for all trace */
 150         DB_CMD("alltrace",      db_stack_trace_all,     DB_CMD_MEMSAFE),
 151         DB_CMD("where",         db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 152         DB_CMD("bt",            db_stack_trace,         CS_OWN|DB_CMD_MEMSAFE),
 153         DB_CMD("call",          db_fncall,              CS_OWN),
 154         DB_CMD("ps",            db_ps,                  DB_CMD_MEMSAFE),
 155         DB_CMD("gdb",           db_gdb,                 0),
 156         DB_CMD("halt",          db_halt,                DB_CMD_MEMSAFE),
 157         DB_CMD("reboot",        db_reset,               DB_CMD_MEMSAFE),
 158         DB_CMD("reset",         db_reset,               DB_CMD_MEMSAFE),
 159         DB_CMD("kill",          db_kill,                CS_OWN|DB_CMD_MEMSAFE),
 160         DB_CMD("watchdog",      db_watchdog,            CS_OWN|DB_CMD_MEMSAFE),
 161         DB_CMD("thread",        db_set_thread,          0),
 162         DB_CMD("run",           db_run_cmd,             CS_OWN|DB_CMD_MEMSAFE),
 163         DB_CMD("script",        db_script_cmd,          CS_OWN|DB_CMD_MEMSAFE),
 164         DB_CMD("scripts",       db_scripts_cmd,         DB_CMD_MEMSAFE),
 165         DB_CMD("unscript",      db_unscript_cmd,        CS_OWN|DB_CMD_MEMSAFE),
 166         DB_CMD("capture",       db_capture_cmd,         CS_OWN|DB_CMD_MEMSAFE),
 167         DB_CMD("textdump",      db_textdump_cmd,        CS_OWN|DB_CMD_MEMSAFE),
 168         DB_CMD("findstack",     db_findstack_cmd,       0),
 169 };
 170 struct db_command_table db_cmd_table = LIST_HEAD_INITIALIZER(db_cmd_table);
 171
 172 #undef DB_CMD
 173 #undef DB_TABLE
 174
 175 static struct db_command *db_last_command = NULL;
 176
 177 /*
 178  * if 'ed' style: 'dot' is set at start of last item printed,
 179  * and '+' points to next line.
 180  * Otherwise: 'dot' points to next item, '..' points to last.
 181  */
 182 static bool     db_ed_style = true;
 183
 184 /*
 185  * Utility routine - discard tokens through end-of-line.
 186  */
 187 void
 188 db_skip_to_eol(void)
 189 {
 190         int t;
 191
 192         do {
 193                 t = db_read_token();
 194         } while (t != tEOL);
 195 }
 196
 197 /*
 198  * Results of command search.
 199  */
 200 #define CMD_UNIQUE      0
 201 #define CMD_FOUND       1
 202 #define CMD_NONE        2
 203 #define CMD_AMBIGUOUS   3
 204 #define CMD_HELP        4
 205
 206 static void     db_cmd_match(char *name, struct db_command *cmd,
 207                     struct db_command **cmdp, int *resultp);
 208 static void     db_cmd_list(struct db_command_table *table);
 209 static int      db_cmd_search(char *name, struct db_command_table *table,
 210                     struct db_command **cmdp);
 211 static void     db_command(struct db_command **last_cmdp,
 212                     struct db_command_table *cmd_table, bool dopager);
 213
 214 /*
 215  * Initialize the command lists from the static tables.
 216  */
 217 void
 218 db_command_init(void)
 219 {
 220         int i;
 221
 222         for (i = 0; i < nitems(db_cmds); i++)
 223                 db_command_register(&db_cmd_table, &db_cmds[i]);
 224         for (i = 0; i < nitems(db_show_cmds); i++)
 225                 db_command_register(&db_show_table, &db_show_cmds[i]);
 226         for (i = 0; i < nitems(db_show_active_cmds); i++)
 227                 db_command_register(&db_show_active_table,
 228                     &db_show_active_cmds[i]);
 229         for (i = 0; i < nitems(db_show_all_cmds); i++)
 230                 db_command_register(&db_show_all_table, &db_show_all_cmds[i]);
 231 }
 232
 233 /*
 234  * Register a command.
 235  */
 236 void
 237 db_command_register(struct db_command_table *list, struct db_command *cmd)
 238 {
 239         struct db_command *c, *last;
 240
 241 #ifdef MAC
 242         if (mac_ddb_command_register(list, cmd)) {
 243                 printf("%s: MAC policy refused registration of command %s\n",
 244                     __func__, cmd->name);
 245                 return;
 246         }
 247 #endif
 248         last = NULL;
 249         LIST_FOREACH(c, list, next) {
 250                 int n = strcmp(cmd->name, c->name);
 251
 252                 /* Check that the command is not already present. */
 253                 if (n == 0) {
 254                         printf("%s: Warning, the command \"%s\" already exists;"
 255                              " ignoring request\n", __func__, cmd->name);
 256                         return;
 257                 }
 258                 if (n < 0) {
 259                         /* NB: keep list sorted lexicographically */
 260                         LIST_INSERT_BEFORE(c, cmd, next);
 261                         return;
 262                 }
 263                 last = c;
 264         }
 265         if (last == NULL)
 266                 LIST_INSERT_HEAD(list, cmd, next);
 267         else
 268                 LIST_INSERT_AFTER(last, cmd, next);
 269 }
 270
 271 /*
 272  * Remove a command previously registered with db_command_register.
 273  */
 274 void
 275 db_command_unregister(struct db_command_table *list, struct db_command *cmd)
 276 {
 277         struct db_command *c;
 278
 279         LIST_FOREACH(c, list, next) {
 280                 if (cmd == c) {
 281                         LIST_REMOVE(cmd, next);
 282                         return;
 283                 }
 284         }
 285         /* NB: intentionally quiet */
 286 }
 287
 288 /*
 289  * Helper function to match a single command.
 290  */
 291 static void
 292 db_cmd_match(char *name, struct db_command *cmd, struct db_command **cmdp,
 293     int *resultp)
 294 {
 295         char *lp, *rp;
 296         int c;
 297
 298         lp = name;
 299         rp = cmd->name;
 300         while ((c = *lp) == *rp) {
 301                 if (c == 0) {
 302                         /* complete match */
 303                         *cmdp = cmd;
 304                         *resultp = CMD_UNIQUE;
 305                         return;
 306                 }
 307                 lp++;
 308                 rp++;
 309         }
 310         if (c == 0) {
 311                 /* end of name, not end of command -
 312                    partial match */
 313                 if (*resultp == CMD_FOUND) {
 314                         *resultp = CMD_AMBIGUOUS;
 315                         /* but keep looking for a full match -
 316                            this lets us match single letters */
 317                 } else if (*resultp == CMD_NONE) {
 318                         *cmdp = cmd;
 319                         *resultp = CMD_FOUND;
 320                 }
 321         }
 322 }
 323
 324 /*
 325  * Search for command prefix.
 326  */
 327 static int
 328 db_cmd_search(char *name, struct db_command_table *table,
 329     struct db_command **cmdp)
 330 {
 331         struct db_command *cmd;
 332         int result = CMD_NONE;
 333
 334         LIST_FOREACH(cmd, table, next) {
 335                 db_cmd_match(name,cmd,cmdp,&result);
 336                 if (result == CMD_UNIQUE)
 337                         break;
 338         }
 339
 340         if (result == CMD_NONE) {
 341                 /* check for 'help' */
 342                 if (name[0] == 'h' && name[1] == 'e'
 343                     && name[2] == 'l' && name[3] == 'p')
 344                         result = CMD_HELP;
 345         }
 346         return (result);
 347 }
 348
 349 static void
 350 db_cmd_list(struct db_command_table *table)
 351 {
 352         struct db_command *cmd;
 353         int have_subcommands;
 354
 355         have_subcommands = 0;
 356         LIST_FOREACH(cmd, table, next) {
 357                 if (cmd->more != NULL)
 358                         have_subcommands++;
 359                 db_printf("%-16s", cmd->name);
 360                 db_end_line(16);
 361         }
 362
 363         if (have_subcommands > 0) {
 364                 db_printf("\nThe following have subcommands; append \"help\" "
 365                     "to list (e.g. \"show help\"):\n");
 366                 LIST_FOREACH(cmd, table, next) {
 367                         if (cmd->more == NULL)
 368                                 continue;
 369                         db_printf("%-16s", cmd->name);
 370                         db_end_line(16);
 371                 }
 372         }
 373 }
 374
 375 static void
 376 db_command(struct db_command **last_cmdp, struct db_command_table *cmd_table,
 377     bool dopager)
 378 {
 379         char modif[TOK_STRING_SIZE];
 380         struct db_command *cmd = NULL;
 381         db_expr_t addr, count;
 382         int t, result;
 383         bool have_addr = false;
 384
 385         t = db_read_token();
 386         if (t == tEOL) {
 387                 /* empty line repeats last command, at 'next' */
 388                 cmd = *last_cmdp;
 389                 addr = (db_expr_t)db_next;
 390                 have_addr = false;
 391                 count = 1;
 392                 modif[0] = '\0';
 393         } else if (t == tEXCL) {
 394                 db_fncall((db_expr_t)0, false, (db_expr_t)0, NULL);
 395                 return;
 396         } else if (t != tIDENT) {
 397                 db_printf("Unrecognized input; use \"help\" "
 398                     "to list available commands\n");
 399                 db_flush_lex();
 400                 return;
 401         } else {
 402                 /*
 403                  * Search for command
 404                  */
 405                 while (cmd_table != NULL) {
 406                         result = db_cmd_search(db_tok_string, cmd_table, &cmd);
 407                         switch (result) {
 408                         case CMD_NONE:
 409                                 db_printf("No such command; use \"help\" "
 410                                     "to list available commands\n");
 411                                 db_flush_lex();
 412                                 return;
 413                         case CMD_AMBIGUOUS:
 414                                 db_printf("Ambiguous\n");
 415                                 db_flush_lex();
 416                                 return;
 417                         case CMD_HELP:
 418                                 if (cmd_table == &db_cmd_table) {
 419                                         db_printf("This is ddb(4), the kernel debugger; "
 420                                             "see https://man.FreeBSD.org/ddb/4 for help.\n");
 421                                         db_printf("Use \"bt\" for backtrace, \"dump\" for "
 422                                             "kernel core dump, \"reset\" to reboot.\n");
 423                                         db_printf("Available commands:\n");
 424                                 }
 425                                 db_cmd_list(cmd_table);
 426                                 db_flush_lex();
 427                                 return;
 428                         case CMD_UNIQUE:
 429                         case CMD_FOUND:
 430                                 break;
 431                         }
 432                         if ((cmd_table = cmd->more) != NULL) {
 433                                 t = db_read_token();
 434                                 if (t != tIDENT) {
 435                                         db_printf("Subcommand required; "
 436                                             "available subcommands:\n");
 437                                         db_cmd_list(cmd_table);
 438                                         db_flush_lex();
 439                                         return;
 440                                 }
 441                         }
 442                 }
 443
 444                 if ((cmd->flag & CS_OWN) == 0) {
 445                         /*
 446                          * Standard syntax:
 447                          * command [/modifier] [addr] [,count]
 448                          */
 449                         t = db_read_token();
 450                         if (t == tSLASH) {
 451                                 t = db_read_token();
 452                                 if (t != tIDENT) {
 453                                         db_printf("Bad modifier\n");
 454                                         db_flush_lex();
 455                                         return;
 456                                 }
 457                                 db_strcpy(modif, db_tok_string);
 458                         } else {
 459                                 db_unread_token(t);
 460                                 modif[0] = '\0';
 461                         }
 462
 463                         if (db_expression(&addr)) {
 464                                 db_dot = (db_addr_t) addr;
 465                                 db_last_addr = db_dot;
 466                                 have_addr = true;
 467                         } else {
 468                                 addr = (db_expr_t) db_dot;
 469                                 have_addr = false;
 470                         }
 471
 472                         t = db_read_token();
 473                         if (t == tCOMMA) {
 474                                 if (!db_expression(&count)) {
 475                                         db_printf("Count missing\n");
 476                                         db_flush_lex();
 477                                         return;
 478                                 }
 479                         } else {
 480                                 db_unread_token(t);
 481                                 count = -1;
 482                         }
 483
 484                         if ((cmd->flag & CS_MORE) == 0) {
 485                                 db_skip_to_eol();
 486                         }
 487                 }
 488         }
 489
 490         *last_cmdp = cmd;
 491         if (cmd != NULL) {
 492 #ifdef MAC
 493                 if (mac_ddb_command_exec(cmd, addr, have_addr, count, modif)) {
 494                         db_printf("MAC prevented execution of command %s\n",
 495                             cmd->name);
 496                         return;
 497                 }
 498 #endif
 499                 /*
 500                  * Execute the command.
 501                  */
 502                 if (dopager)
 503                         db_enable_pager();
 504                 else
 505                         db_disable_pager();
 506                 (*cmd->fcn)(addr, have_addr, count, modif);
 507                 if (dopager)
 508                         db_disable_pager();
 509
 510                 if (cmd->flag & CS_SET_DOT) {
 511                         /*
 512                          * If command changes dot, set dot to previous address
 513                          * displayed (if 'ed' style).
 514                          */
 515                         db_dot = db_ed_style ? db_prev : db_next;
 516                 } else {
 517                         /*
 518                          * If command does not change dot, set 'next' location
 519                          * to be the same.
 520                          */
 521                         db_next = db_dot;
 522                 }
 523         }
 524 }
 525
 526 /*
 527  * At least one non-optional command must be implemented using
 528  * DB_COMMAND() so that db_cmd_set gets created.  Here is one.
 529  */
 530 DB_COMMAND_FLAGS(panic, db_panic, DB_CMD_MEMSAFE)
 531 {
 532         db_disable_pager();
 533         panic("from debugger");
 534 }
 535
 536 void
 537 db_command_loop(void)
 538 {
 539         /*
 540          * Initialize 'prev' and 'next' to dot.
 541          */
 542         db_prev = db_dot;
 543         db_next = db_dot;
 544
 545         db_cmd_loop_done = 0;
 546         while (!db_cmd_loop_done) {
 547                 if (db_print_position() != 0)
 548                         db_printf("\n");
 549
 550                 db_printf("db> ");
 551                 (void)db_read_line();
 552
 553                 db_command(&db_last_command, &db_cmd_table, /* dopager */ true);
 554         }
 555 }
 556
 557 /*
 558  * Execute a command on behalf of a script.  The caller is responsible for
 559  * making sure that the command string is < DB_MAXLINE or it will be
 560  * truncated.
 561  *
 562  * XXXRW: Runs by injecting faked input into DDB input stream; it would be
 563  * nicer to use an alternative approach that didn't mess with the previous
 564  * command buffer.
 565  */
 566 void
 567 db_command_script(const char *command)
 568 {
 569         db_prev = db_next = db_dot;
 570         db_inject_line(command);
 571         db_command(&db_last_command, &db_cmd_table, /* dopager */ false);
 572 }
 573
 574 void
 575 db_error(const char *s)
 576 {
 577         if (s)
 578             db_printf("%s", s);
 579         db_flush_lex();
 580         kdb_reenter_silent();
 581 }
 582
 583 static void
 584 db_dump(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
 585 {
 586         int error;
 587
 588         if (textdump_pending) {
 589                 db_printf("textdump_pending set.\n"
 590                     "run \"textdump unset\" first or \"textdump dump\" for a textdump.\n");
 591                 return;
 592         }
 593         error = doadump(false);
 594         if (error) {
 595                 db_printf("Cannot dump: ");
 596                 switch (error) {
 597                 case EBUSY:
 598                         db_printf("debugger got invoked while dumping.\n");
 599                         break;
 600                 case ENXIO:
 601                         db_printf("no dump device specified.\n");
 602                         break;
 603                 default:
 604                         db_printf("unknown error (error=%d).\n", error);
 605                         break;
 606                 }
 607         }
 608 }
 609
 610 /*
 611  * Call random function:
 612  * !expr(arg,arg,arg)
 613  */
 614
 615 /* The generic implementation supports a maximum of 10 arguments. */
 616 typedef db_expr_t __db_f(db_expr_t, db_expr_t, db_expr_t, db_expr_t,
 617     db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t);
 618
 619 static __inline int
 620 db_fncall_generic(db_expr_t addr, db_expr_t *rv, int nargs, db_expr_t args[])
 621 {
 622         __db_f *f = (__db_f *)addr;
 623
 624         if (nargs > 10) {
 625                 db_printf("Too many arguments (max 10)\n");
 626                 return (0);
 627         }
 628         *rv = (*f)(args[0], args[1], args[2], args[3], args[4], args[5],
 629             args[6], args[7], args[8], args[9]);
 630         return (1);
 631 }
 632
 633 static void
 634 db_fncall(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
 635 {
 636         db_expr_t       fn_addr;
 637         db_expr_t       args[DB_MAXARGS];
 638         int             nargs = 0;
 639         db_expr_t       retval;
 640         int             t;
 641
 642         if (!db_expression(&fn_addr)) {
 643             db_printf("Bad function\n");
 644             db_flush_lex();
 645             return;
 646         }
 647
 648         t = db_read_token();
 649         if (t == tLPAREN) {
 650             if (db_expression(&args[0])) {
 651                 nargs++;
 652                 while ((t = db_read_token()) == tCOMMA) {
 653                     if (nargs == DB_MAXARGS) {
 654                         db_printf("Too many arguments (max %d)\n", DB_MAXARGS);
 655                         db_flush_lex();
 656                         return;
 657                     }
 658                     if (!db_expression(&args[nargs])) {
 659                         db_printf("Argument missing\n");
 660                         db_flush_lex();
 661                         return;
 662                     }
 663                     nargs++;
 664                 }
 665                 db_unread_token(t);
 666             }
 667             if (db_read_token() != tRPAREN) {
 668                 db_printf("Mismatched parens\n");
 669                 db_flush_lex();
 670                 return;
 671             }
 672         }
 673         db_skip_to_eol();
 674         db_disable_pager();
 675
 676         if (DB_CALL(fn_addr, &retval, nargs, args))
 677                 db_printf("= %#lr\n", (long)retval);
 678 }
 679
 680 static void
 681 db_halt(db_expr_t dummy, bool dummy2, db_expr_t dummy3, char *dummy4)
 682 {
 683
 684         cpu_halt();
 685 }
 686
 687 static void
 688 db_kill(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
 689 {
 690         db_expr_t old_radix, pid, sig;
 691         struct proc *p;
 692
 693 #define DB_ERROR(f)     do { db_printf f; db_flush_lex(); goto out; } while (0)
 694
 695         /*
 696          * PIDs and signal numbers are typically represented in base
 697          * 10, so make that the default here.  It can, of course, be
 698          * overridden by specifying a prefix.
 699          */
 700         old_radix = db_radix;
 701         db_radix = 10;
 702         /* Retrieve arguments. */
 703         if (!db_expression(&sig))
 704                 DB_ERROR(("Missing signal number\n"));
 705         if (!db_expression(&pid))
 706                 DB_ERROR(("Missing process ID\n"));
 707         db_skip_to_eol();
 708         if (!_SIG_VALID(sig))
 709                 DB_ERROR(("Signal number out of range\n"));
 710
 711         /*
 712          * Find the process in question.  allproc_lock is not needed
 713          * since we're in DDB.
 714          */
 715         /* sx_slock(&allproc_lock); */
 716         FOREACH_PROC_IN_SYSTEM(p)
 717             if (p->p_pid == pid)
 718                     break;
 719         /* sx_sunlock(&allproc_lock); */
 720         if (p == NULL)
 721                 DB_ERROR(("Can't find process with pid %ld\n", (long) pid));
 722
 723         /* If it's already locked, bail; otherwise, do the deed. */
 724         if (PROC_TRYLOCK(p) == 0)
 725                 DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
 726         else {
 727                 pksignal(p, sig, NULL);
 728                 PROC_UNLOCK(p);
 729         }
 730
 731 out:
 732         db_radix = old_radix;
 733 #undef DB_ERROR
 734 }
 735
 736 /*
 737  * Reboot.  In case there is an additional argument, take it as delay in
 738  * seconds.  Default to 15s if we cannot parse it and make sure we will
 739  * never wait longer than 1 week.  Some code is similar to
 740  * kern_shutdown.c:shutdown_panic().
 741  */
 742 #ifndef DB_RESET_MAXDELAY
 743 #define DB_RESET_MAXDELAY       (3600 * 24 * 7)
 744 #endif
 745
 746 static void
 747 db_reset(db_expr_t addr, bool have_addr, db_expr_t count __unused,
 748     char *modif)
 749 {
 750         int delay, loop;
 751
 752         if (have_addr) {
 753                 delay = (int)db_hex2dec(addr);
 754
 755                 /* If we parse to fail, use 15s. */
 756                 if (delay == -1)
 757                         delay = 15;
 758
 759                 /* Cap at one week. */
 760                 if ((uintmax_t)delay > (uintmax_t)DB_RESET_MAXDELAY)
 761                         delay = DB_RESET_MAXDELAY;
 762
 763                 db_printf("Automatic reboot in %d seconds - "
 764                     "press a key on the console to abort\n", delay);
 765                 for (loop = delay * 10; loop > 0; --loop) {
 766                         DELAY(1000 * 100); /* 1/10th second */
 767                         /* Did user type a key? */
 768                         if (cncheckc() != -1)
 769                                 return;
 770                 }
 771         }
 772
 773         /*
 774          * Conditionally try the standard reboot path, so any registered
 775          * shutdown/reset handlers have a chance to run first. Some platforms
 776          * may not support the machine-dependent mechanism used by cpu_reset()
 777          * and rely on some other non-standard mechanism to perform the reset.
 778          * For example, the BCM2835 watchdog driver or gpio-poweroff driver.
 779          */
 780         if (modif[0] != 's') {
 781                 kern_reboot(RB_NOSYNC);
 782                 /* NOTREACHED */
 783         }
 784
 785         cpu_reset();
 786 }
 787
 788 static void
 789 db_watchdog(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
 790 {
 791         db_expr_t old_radix, tout;
 792         int err, i;
 793
 794         old_radix = db_radix;
 795         db_radix = 10;
 796         err = db_expression(&tout);
 797         db_skip_to_eol();
 798         db_radix = old_radix;
 799
 800         /* If no argument is provided the watchdog will just be disabled. */
 801         if (err == 0) {
 802                 db_printf("No argument provided, disabling watchdog\n");
 803                 tout = 0;
 804         } else if ((tout & WD_INTERVAL) == WD_TO_NEVER) {
 805                 db_error("Out of range watchdog interval\n");
 806                 return;
 807         }
 808         EVENTHANDLER_INVOKE(watchdog_list, tout, &i);
 809 }
 810
 811 static void
 812 db_gdb(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
 813 {
 814
 815         if (kdb_dbbe_select("gdb") != 0) {
 816                 db_printf("The remote GDB backend could not be selected.\n");
 817                 return;
 818         }
 819         /*
 820          * Mark that we are done in the debugger.  kdb_trap()
 821          * should re-enter with the new backend.
 822          */
 823         db_cmd_loop_done = 1;
 824         db_printf("(ctrl-c will return control to ddb)\n");
 825 }
 826
 827 static void
 828 db_stack_trace(db_expr_t tid, bool hastid, db_expr_t count, char *modif)
 829 {
 830         struct thread *td;
 831         db_expr_t radix;
 832         pid_t pid;
 833         int t;
 834
 835         /*
 836          * We parse our own arguments. We don't like the default radix.
 837          */
 838         radix = db_radix;
 839         db_radix = 10;
 840         hastid = db_expression(&tid);
 841         t = db_read_token();
 842         if (t == tCOMMA) {
 843                 if (!db_expression(&count)) {
 844                         db_printf("Count missing\n");
 845                         db_flush_lex();
 846                         db_radix = radix;
 847                         return;
 848                 }
 849         } else {
 850                 db_unread_token(t);
 851                 count = -1;
 852         }
 853         db_skip_to_eol();
 854         db_radix = radix;
 855
 856         if (hastid) {
 857                 td = kdb_thr_lookup((lwpid_t)tid);
 858                 if (td == NULL)
 859                         td = kdb_thr_from_pid((pid_t)tid);
 860                 if (td == NULL) {
 861                         db_printf("Thread %d not found\n", (int)tid);
 862                         return;
 863                 }
 864         } else
 865                 td = kdb_thread;
 866         if (td->td_proc != NULL)
 867                 pid = td->td_proc->p_pid;
 868         else
 869                 pid = -1;
 870         db_printf("Tracing pid %d tid %ld td %p\n", pid, (long)td->td_tid, td);
 871         if (td->td_proc != NULL && (td->td_proc->p_flag & P_INMEM) == 0)
 872                 db_printf("--- swapped out\n");
 873         else
 874                 db_trace_thread(td, count);
 875 }
 876
 877 static void
 878 _db_stack_trace_all(bool active_only)
 879 {
 880         struct thread *td;
 881         jmp_buf jb;
 882         void *prev_jb;
 883
 884         for (td = kdb_thr_first(); td != NULL; td = kdb_thr_next(td)) {
 885                 prev_jb = kdb_jmpbuf(jb);
 886                 if (setjmp(jb) == 0) {
 887                         if (TD_IS_RUNNING(td))
 888                                 db_printf("\nTracing command %s pid %d"
 889                                     " tid %ld td %p (CPU %d)\n",
 890                                     td->td_proc->p_comm, td->td_proc->p_pid,
 891                                     (long)td->td_tid, td, td->td_oncpu);
 892                         else if (active_only)
 893                                 continue;
 894                         else
 895                                 db_printf("\nTracing command %s pid %d"
 896                                     " tid %ld td %p\n", td->td_proc->p_comm,
 897                                     td->td_proc->p_pid, (long)td->td_tid, td);
 898                         if (td->td_proc->p_flag & P_INMEM)
 899                                 db_trace_thread(td, -1);
 900                         else
 901                                 db_printf("--- swapped out\n");
 902                         if (db_pager_quit) {
 903                                 kdb_jmpbuf(prev_jb);
 904                                 return;
 905                         }
 906                 }
 907                 kdb_jmpbuf(prev_jb);
 908         }
 909 }
 910
 911 static void
 912 db_stack_trace_active(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
 913     char *dummy4)
 914 {
 915
 916         _db_stack_trace_all(true);
 917 }
 918
 919 static void
 920 db_stack_trace_all(db_expr_t dummy, bool dummy2, db_expr_t dummy3,
 921     char *dummy4)
 922 {
 923
 924         _db_stack_trace_all(false);
 925 }
 926
 927 /*
 928  * Take the parsed expression value from the command line that was parsed
 929  * as a hexadecimal value and convert it as if the expression was parsed
 930  * as a decimal value.  Returns -1 if the expression was not a valid
 931  * decimal value.
 932  */
 933 db_expr_t
 934 db_hex2dec(db_expr_t expr)
 935 {
 936         uintptr_t x, y;
 937         db_expr_t val;
 938
 939         y = 1;
 940         val = 0;
 941         x = expr;
 942         while (x != 0) {
 943                 if (x % 16 > 9)
 944                         return (-1);
 945                 val += (x % 16) * (y);
 946                 x >>= 4;
 947                 y *= 10;
 948         }
 949         return (val);
 950 }