osfmk/ddb/db_command.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52 /*
  53  *      Author: David B. Golub, Carnegie Mellon University
  54  *      Date:   7/90
  55  */
  56
  57 /*
  58  * Command dispatcher.
  59  */
  60 #include <cpus.h>
  61 #include <norma_vm.h>
  62 #ifdef  AT386
  63 #include <norma_scsi.h>
  64 #endif  /* AT386 */
  65
  66 #include <mach/boolean.h>
  67 #include <string.h>
  68 #include <machine/db_machdep.h>
  69
  70 #if defined(__alpha)
  71 #  include <kdebug.h>
  72 #  if KDEBUG
  73 #    include <machine/kdebug.h>
  74 #  endif
  75 #endif /* defined(__alpha) */
  76
  77 #include <ddb/db_lex.h>
  78 #include <ddb/db_output.h>
  79 #include <ddb/db_break.h>
  80 #include <ddb/db_command.h>
  81 #include <ddb/db_cond.h>
  82 #include <ddb/db_examine.h>
  83 #include <ddb/db_expr.h>
  84 #include <ppc/db_low_trace.h>
  85 #include <ddb/db_macro.h>
  86 #include <ddb/db_print.h>
  87 #include <ddb/db_run.h>
  88 #include <ddb/db_task_thread.h>
  89 #include <ddb/db_variables.h>
  90 #include <ddb/db_watch.h>
  91 #include <ddb/db_write_cmd.h>
  92 #include <ddb/tr.h>
  93
  94 #include <machine/setjmp.h>
  95 #include <kern/thread.h>
  96
  97 #include <kern/misc_protos.h>
  98 #include <vm/vm_print.h>
  99 #include <ipc/ipc_print.h>
 100 #include <kern/kern_print.h>
 101 #include <machine/db_machdep.h>         /* For db_stack_trace_cmd(). */
 102 #include <kern/zalloc.h>        /* For db_show_one_zone, db_show_all_zones. */
 103 #include <kern/lock.h>                  /* For db_show_all_slocks(). */
 104
 105 #if     NORMA_VM
 106 #include <xmm/xmm_obj.h>
 107 #endif  /* NORMA_VM */
 108
 109 /*
 110  * Exported global variables
 111  */
 112 boolean_t       db_cmd_loop_done;
 113 jmp_buf_t       *db_recover = 0;
 114 db_addr_t       db_dot;
 115 db_addr_t       db_last_addr;
 116 db_addr_t       db_prev;
 117 db_addr_t       db_next;
 118
 119 /*
 120  * if 'ed' style: 'dot' is set at start of last item printed,
 121  * and '+' points to next line.
 122  * Otherwise: 'dot' points to next item, '..' points to last.
 123  */
 124 boolean_t       db_ed_style = TRUE;
 125
 126 /*
 127  * Results of command search.
 128  */
 129 #define CMD_UNIQUE      0
 130 #define CMD_FOUND       1
 131 #define CMD_NONE        2
 132 #define CMD_AMBIGUOUS   3
 133 #define CMD_HELP        4
 134
 135 /* Prototypes for functions local to this file.  XXX -- should be static!
 136  */
 137
 138 void db_command(
 139         struct db_command       **last_cmdp,    /* IN_OUT */
 140         db_expr_t               *last_countp,   /* IN_OUT */
 141         char                    *last_modifp,   /* IN_OUT */
 142         struct db_command       *cmd_table);
 143
 144 void db_help_cmd(void);
 145
 146 void db_output_prompt(void);
 147
 148 void db_fncall(void);
 149
 150 void db_cmd_list(struct db_command *table);
 151
 152 int db_cmd_search(
 153         char *                  name,
 154         struct db_command *     table,
 155         struct db_command **    cmdp);  /* out */
 156
 157 void db_command_list(
 158         struct db_command       **last_cmdp,    /* IN_OUT */
 159         db_expr_t               *last_countp,   /* IN_OUT */
 160         char                    *last_modifp,   /* IN_OUT */
 161         struct db_command       *cmd_table);
 162
 163
 164
 165 /*
 166  * Search for command prefix.
 167  */
 168 int
 169 db_cmd_search(
 170         char *                  name,
 171         struct db_command *     table,
 172         struct db_command **    cmdp)   /* out */
 173 {
 174         struct db_command       *cmd;
 175         int             result = CMD_NONE;
 176
 177         for (cmd = table; cmd->name != 0; cmd++) {
 178             register char *lp;
 179             register char *rp;
 180             register int  c;
 181
 182             lp = name;
 183             rp = cmd->name;
 184             while ((c = *lp) == *rp) {
 185                 if (c == 0) {
 186                     /* complete match */
 187                     *cmdp = cmd;
 188                     return (CMD_UNIQUE);
 189                 }
 190                 lp++;
 191                 rp++;
 192             }
 193             if (c == 0) {
 194                 /* end of name, not end of command -
 195                    partial match */
 196                 if (result == CMD_FOUND) {
 197                     result = CMD_AMBIGUOUS;
 198                     /* but keep looking for a full match -
 199                        this lets us match single letters */
 200                 }
 201                 else {
 202                     *cmdp = cmd;
 203                     result = CMD_FOUND;
 204                 }
 205             }
 206         }
 207         if (result == CMD_NONE) {
 208             /* check for 'help' */
 209             if (!strncmp(name, "help", strlen(name)))
 210                 result = CMD_HELP;
 211         }
 212         return (result);
 213 }
 214
 215 void
 216 db_cmd_list(struct db_command *table)
 217 {
 218         register struct db_command *new;
 219         register struct db_command *old;
 220         register struct db_command *cur;
 221         unsigned int l;
 222         unsigned int len;
 223
 224         len = 1;
 225         for (cur = table; cur->name != 0; cur++)
 226             if ((l = strlen(cur->name)) >= len)
 227                 len = l + 1;
 228
 229         old = (struct db_command *)0;
 230         for (;;) {
 231             new = (struct db_command *)0;
 232             for (cur = table; cur->name != 0; cur++)
 233                 if ((new == (struct db_command *)0 ||
 234                      strcmp(cur->name, new->name) < 0) &&
 235                     (old == (struct db_command *)0 ||
 236                      strcmp(cur->name, old->name) > 0))
 237                     new = cur;
 238             if (new == (struct db_command *)0)
 239                     return;
 240             db_reserve_output_position(len);
 241             db_printf("%-*s", len, new->name);
 242             old = new;
 243         }
 244 }
 245
 246 void
 247 db_command(
 248         struct db_command       **last_cmdp,    /* IN_OUT */
 249         db_expr_t               *last_countp,   /* IN_OUT */
 250         char                    *last_modifp,   /* IN_OUT */
 251         struct db_command       *cmd_table)
 252 {
 253         struct db_command       *cmd;
 254         int             t;
 255         char            modif[TOK_STRING_SIZE];
 256         char            *modifp = &modif[0];
 257         db_expr_t       addr, count;
 258         boolean_t       have_addr;
 259         int             result;
 260
 261         t = db_read_token();
 262         if (t == tEOL || t == tSEMI_COLON) {
 263             /* empty line repeats last command, at 'next' */
 264             cmd = *last_cmdp;
 265             count = *last_countp;
 266             modifp = last_modifp;
 267             addr = (db_expr_t)db_next;
 268             have_addr = FALSE;
 269             if (t == tSEMI_COLON)
 270                 db_unread_token(t);
 271         }
 272         else if (t == tEXCL) {
 273             db_fncall();
 274             return;
 275         }
 276         else if (t != tIDENT) {
 277             db_printf("?\n");
 278             db_flush_lex();
 279             return;
 280         }
 281         else {
 282             /*
 283              * Search for command
 284              */
 285             while (cmd_table) {
 286                 result = db_cmd_search(db_tok_string,
 287                                        cmd_table,
 288                                        &cmd);
 289                 switch (result) {
 290                     case CMD_NONE:
 291                         if (db_exec_macro(db_tok_string) == 0)
 292                             return;
 293                         db_printf("No such command \"%s\"\n", db_tok_string);
 294                         db_flush_lex();
 295                         return;
 296                     case CMD_AMBIGUOUS:
 297                         db_printf("Ambiguous\n");
 298                         db_flush_lex();
 299                         return;
 300                     case CMD_HELP:
 301                         db_cmd_list(cmd_table);
 302                         db_flush_lex();
 303                         return;
 304                     default:
 305                         break;
 306                 }
 307                 if ((cmd_table = cmd->more) != 0) {
 308                     t = db_read_token();
 309                     if (t != tIDENT) {
 310                         db_cmd_list(cmd_table);
 311                         db_flush_lex();
 312                         return;
 313                     }
 314                 }
 315             }
 316
 317             if ((cmd->flag & CS_OWN) == 0) {
 318                 /*
 319                  * Standard syntax:
 320                  * command [/modifier] [addr] [,count]
 321                  */
 322                 t = db_read_token();
 323                 if (t == tSLASH) {
 324                     t = db_read_token();
 325                     if (t != tIDENT) {
 326                         db_printf("Bad modifier \"/%s\"\n", db_tok_string);
 327                         db_flush_lex();
 328                         return;
 329                     }
 330                     strcpy(modif, db_tok_string);
 331                 }
 332                 else {
 333                     db_unread_token(t);
 334                     modif[0] = '\0';
 335                 }
 336
 337                 if (db_expression(&addr)) {
 338                     db_dot = (db_addr_t) addr;
 339                     db_last_addr = db_dot;
 340                     have_addr = TRUE;
 341                 }
 342                 else {
 343                     addr = (db_expr_t) db_dot;
 344                     have_addr = FALSE;
 345                 }
 346                 t = db_read_token();
 347                 if (t == tCOMMA) {
 348                     if (!db_expression(&count)) {
 349                         db_printf("Count missing after ','\n");
 350                         db_flush_lex();
 351                         return;
 352                     }
 353                 }
 354                 else {
 355                     db_unread_token(t);
 356                     count = -1;
 357                 }
 358             }
 359         }
 360         if (cmd != 0) {
 361             /*
 362              * Execute the command.
 363              */
 364             (*cmd->fcn)(addr, have_addr, count, modifp);
 365
 366             if (cmd->flag & CS_SET_DOT) {
 367                 /*
 368                  * If command changes dot, set dot to
 369                  * previous address displayed (if 'ed' style).
 370                  */
 371                 if (db_ed_style) {
 372                     db_dot = db_prev;
 373                 }
 374                 else {
 375                     db_dot = db_next;
 376                 }
 377             }
 378             else {
 379                 /*
 380                  * If command does not change dot,
 381                  * set 'next' location to be the same.
 382                  */
 383                 db_next = db_dot;
 384             }
 385         }
 386         *last_cmdp = cmd;
 387         *last_countp = count;
 388         strcpy(last_modifp, modifp);
 389 }
 390
 391 void
 392 db_command_list(
 393         struct db_command       **last_cmdp,    /* IN_OUT */
 394         db_expr_t               *last_countp,   /* IN_OUT */
 395         char                    *last_modifp,   /* IN_OUT */
 396         struct db_command       *cmd_table)
 397 {
 398         do {
 399             db_command(last_cmdp, last_countp, last_modifp, cmd_table);
 400             db_skip_to_eol();
 401         } while (db_read_token() == tSEMI_COLON && db_cmd_loop_done == 0);
 402 }
 403
 404
 405 extern void     db_system_stats(void);
 406
 407 struct db_command db_show_all_cmds[] = {
 408 #if     USLOCK_DEBUG
 409         { "slocks",     (db_func) db_show_all_slocks,           0,      0 },
 410 #endif  /* USLOCK_DEBUG */
 411         { "acts",       db_show_all_acts,                       0,      0 },
 412         { "spaces",     db_show_all_spaces,                     0,      0 },
 413         { "tasks",      db_show_all_acts,                       0,      0 },
 414         /* temporary alias for sanity preservation */
 415         { "threads",    db_show_all_acts,                       0,      0 },
 416         { "zones",      db_show_all_zones,                      0,      0 },
 417         { "vmtask",     db_show_all_task_vm,                    0,      0 },
 418         { (char *)0 }
 419 };
 420
 421 /* XXX */
 422
 423 extern void             db_show_thread_log(void);
 424 extern void             db_show_one_lock(lock_t*);
 425 extern void             db_show_etap_log(db_expr_t, int, db_expr_t, char *);
 426
 427 struct db_command db_show_cmds[] = {
 428         { "all",        0,                              0,      db_show_all_cmds },
 429         { "registers",  db_show_regs,                   0,      0 },
 430         { "variables",  (db_func) db_show_variable,     CS_OWN, 0 },
 431         { "breaks",     (db_func) db_listbreak_cmd,     0,      0 },
 432         { "watches",    (db_func) db_listwatch_cmd,     0,      0 },
 433         { "task",       db_show_one_task,               0,      0 },
 434         { "act",        db_show_one_act,                0,      0 },
 435         { "shuttle",    db_show_shuttle,                0,      0 },
 436 #if 0
 437         { "thread",     db_show_one_thread,             0,      0 },
 438 #endif
 439         { "vmtask",     db_show_one_task_vm,            0,      0 },
 440         { "macro",      (db_func) db_show_macro,        CS_OWN, 0 },
 441         { "runq",       (db_func) db_show_runq,         0,      0 },
 442         { "map",        (db_func) vm_map_print,         0,      0 },
 443         { "object",     (db_func) vm_object_print,      0,      0 },
 444         { "page",       (db_func) vm_page_print,        0,      0 },
 445         { "copy",       (db_func) vm_map_copy_print,    0,      0 },
 446         { "port",       (db_func) ipc_port_print,       0,      0 },
 447         { "pset",       (db_func) ipc_pset_print,       0,      0 },
 448         { "kmsg",       (db_func) ipc_kmsg_print,       0,      0 },
 449         { "msg",        (db_func) ipc_msg_print,        0,      0 },
 450         { "ipc_port",   db_show_port_id,                0,      0 },
 451         { "lock",       (db_func)db_show_one_lock,      0,      0 },
 452 #if     NORMA_VM
 453         { "xmm_obj",    (db_func) xmm_obj_print,        0,      0 },
 454         { "xmm_reply",  (db_func) xmm_reply_print,      0,      0 },
 455 #endif  /* NORMA_VM */
 456 #if     TRACE_BUFFER
 457         { "tr",         db_show_tr,                     0,      0 },
 458 #endif  /* TRACE_BUFFER */
 459         { "space",      db_show_one_space,              0,      0 },
 460         { "system",     (db_func) db_system_stats,      0,      0 },
 461         { "zone",       db_show_one_zone,               0,      0 },
 462         { "simple_lock", db_show_one_simple_lock,       0,      0 },
 463         { "thread_log", (db_func)db_show_thread_log,    0,      0 },
 464         { "shuttle",    db_show_shuttle,                0,      0 },
 465         { "etap_log",   db_show_etap_log,               0,      0 },
 466         { (char *)0, }
 467 };
 468
 469 #if     NCPUS > 1
 470 #define db_switch_cpu kdb_on
 471 extern void     db_switch_cpu(int);
 472 #endif  /* NCPUS > 1 */
 473
 474 struct db_command db_command_table[] = {
 475 #if DB_MACHINE_COMMANDS
 476
 477 /* this must be the first entry, if it exists */
 478         { "machine",    0,                              0,                      0 },
 479 #endif
 480         { "print",      (db_func) db_print_cmd,         CS_OWN,                 0 },
 481         { "examine",    db_examine_cmd,                 CS_MORE|CS_SET_DOT,     0 },
 482         { "x",          db_examine_cmd,                 CS_MORE|CS_SET_DOT,     0 },
 483         { "xf",         db_examine_forward,             CS_SET_DOT,             0 },
 484         { "xb",         db_examine_backward,            CS_SET_DOT,             0 },
 485         { "search",     (db_func) db_search_cmd,        CS_OWN|CS_SET_DOT,      0 },
 486         { "set",        (db_func) db_set_cmd,           CS_OWN,                 0 },
 487         { "write",      db_write_cmd,                   CS_MORE|CS_SET_DOT,     0 },
 488         { "w",          db_write_cmd,                   CS_MORE|CS_SET_DOT,     0 },
 489         { "delete",     (db_func) db_delete_cmd,        CS_OWN,                 0 },
 490         { "d",          (db_func) db_delete_cmd,        CS_OWN,                 0 },
 491         { "break",      db_breakpoint_cmd,              CS_MORE,                0 },
 492         { "dwatch",     db_deletewatch_cmd,             CS_MORE,                0 },
 493         { "watch",      db_watchpoint_cmd,              CS_MORE,                0 },
 494         { "step",       db_single_step_cmd,             0,                      0 },
 495         { "s",          db_single_step_cmd,             0,                      0 },
 496         { "continue",   db_continue_cmd,                0,                      0 },
 497         { "c",          db_continue_cmd,                0,                      0 },
 498         { "gdb",        db_continue_gdb,                0,                      0 },
 499         { "until",      db_trace_until_call_cmd,        0,                      0 },
 500
 501         /* As per request of DNoveck, CR1550, leave this disabled       */
 502 #if 0   /* until CR1440 is fixed, to avoid toe-stubbing                 */
 503         { "next",       db_trace_until_matching_cmd,    0,                      0 },
 504 #endif
 505         { "match",      db_trace_until_matching_cmd,    0       ,               0 },
 506         { "trace",      db_stack_trace_cmd,             0,                      0 },
 507         { "cond",       (db_func) db_cond_cmd,          CS_OWN,                 0 },
 508         { "call",       (db_func) db_fncall,            CS_OWN,                 0 },
 509         { "macro",      (db_func) db_def_macro_cmd,     CS_OWN,                 0 },
 510         { "dmacro",     (db_func) db_del_macro_cmd,     CS_OWN,                 0 },
 511         { "show",       0,                              0,                      db_show_cmds },
 512 #if     NCPUS > 1
 513         { "cpu",        (db_func) db_switch_cpu,        0,                      0 },
 514 #endif  /* NCPUS > 1 */
 515         { "reboot",     (db_func) db_reboot,            0,                      0 },
 516 #if defined(__ppc__)
 517         { "lt",         db_low_trace,                   CS_MORE|CS_SET_DOT,     0 },
 518         { "dl",         db_display_long,                CS_MORE|CS_SET_DOT,     0 },
 519         { "dr",         db_display_real,                CS_MORE|CS_SET_DOT,     0 },
 520         { "dv",         db_display_virtual,             CS_MORE|CS_SET_DOT,     0 },
 521         { "dm",         db_display_mappings,    CS_MORE|CS_SET_DOT,     0 },
 522         { "dp",         db_display_pmap,                CS_MORE,                        0 },
 523         { "ds",         db_display_save,                CS_MORE|CS_SET_DOT,     0 },
 524         { "dx",         db_display_xregs,               CS_MORE|CS_SET_DOT,     0 },
 525         { "dk",         db_display_kmod,                CS_MORE,                        0 },
 526         { "gs",         db_gsnoop,                              CS_MORE,                        0 },
 527 #endif
 528         { (char *)0, }
 529 };
 530
 531 /* this function should be called to install the machine dependent
 532    commands. It should be called before the debugger is enabled  */
 533 void db_machine_commands_install(struct db_command *ptr)
 534 {
 535   db_command_table[0].more = ptr;
 536   return;
 537 }
 538
 539
 540 struct db_command       *db_last_command = 0;
 541 db_expr_t               db_last_count = 0;
 542 char                    db_last_modifier[TOK_STRING_SIZE] = { '\0' };
 543
 544 void
 545 db_help_cmd(void)
 546 {
 547         struct db_command *cmd = db_command_table;
 548
 549         while (cmd->name != 0) {
 550             db_printf("%-12s", cmd->name);
 551             db_end_line();
 552             cmd++;
 553         }
 554 }
 555
 556 int     (*ddb_display)(void);
 557
 558 void
 559 db_command_loop(void)
 560 {
 561         jmp_buf_t db_jmpbuf;
 562         jmp_buf_t *prev = db_recover;
 563         extern int db_output_line;
 564         extern int db_macro_level;
 565         extern int db_indent;
 566
 567         /*
 568          * Initialize 'prev' and 'next' to dot.
 569          */
 570         db_prev = db_dot;
 571         db_next = db_dot;
 572
 573         if (ddb_display)
 574                 (*ddb_display)();
 575
 576         db_cmd_loop_done = 0;
 577         while (!db_cmd_loop_done) {
 578             (void) _setjmp(db_recover = &db_jmpbuf);
 579             db_macro_level = 0;
 580             if (db_print_position() != 0)
 581                 db_printf("\n");
 582             db_output_line = 0;
 583             db_indent = 0;
 584             db_reset_more();
 585             db_output_prompt();
 586
 587             (void) db_read_line("!!");
 588             db_command_list(&db_last_command, &db_last_count,
 589                             db_last_modifier, db_command_table);
 590         }
 591
 592         db_recover = prev;
 593 }
 594
 595 boolean_t
 596 db_exec_cmd_nest(
 597         char    *cmd,
 598         int     size)
 599 {
 600         struct db_lex_context lex_context;
 601
 602         db_cmd_loop_done = 0;
 603         if (cmd) {
 604             db_save_lex_context(&lex_context);
 605             db_switch_input(cmd, size);
 606         }
 607         db_command_list(&db_last_command, &db_last_count,
 608                         db_last_modifier, db_command_table);
 609         if (cmd)
 610             db_restore_lex_context(&lex_context);
 611         return(db_cmd_loop_done == 0);
 612 }
 613
 614 void
 615 db_error(char *s)
 616 {
 617         extern int db_macro_level;
 618
 619 #if defined(__alpha)
 620 #  if KDEBUG
 621         extern boolean_t kdebug_mode;
 622         if (kdebug_mode) {
 623                 if (s) kprintf(DBG_DEBUG, s);
 624                 return;
 625         }
 626 #  endif /* KDEBUG */
 627 #endif /* defined(__alpha) */
 628
 629         db_macro_level = 0;
 630         if (db_recover) {
 631             if (s > (char *)1)
 632                 db_printf(s);
 633             db_flush_lex();
 634             _longjmp(db_recover, (s == (char *)1) ? 2 : 1);
 635         }
 636         else
 637         {
 638             if (s > (char *)1)
 639                 db_printf(s);
 640             panic("db_error");
 641         }
 642 }
 643
 644
 645 /*
 646  * Call random function:
 647  * !expr(arg,arg,arg)
 648  */
 649 void
 650 db_fncall(void)
 651 {
 652         db_expr_t       fn_addr;
 653 #define MAXARGS         11
 654         db_expr_t       args[MAXARGS];
 655         int             nargs = 0;
 656         db_expr_t       retval;
 657         db_expr_t       (*func)(db_expr_t, ...);
 658         int             t;
 659
 660         if (!db_expression(&fn_addr)) {
 661             db_printf("Bad function \"%s\"\n", db_tok_string);
 662             db_flush_lex();
 663             return;
 664         }
 665         func = (db_expr_t (*) (db_expr_t, ...)) fn_addr;
 666
 667         t = db_read_token();
 668         if (t == tLPAREN) {
 669             if (db_expression(&args[0])) {
 670                 nargs++;
 671                 while ((t = db_read_token()) == tCOMMA) {
 672                     if (nargs == MAXARGS) {
 673                         db_printf("Too many arguments\n");
 674                         db_flush_lex();
 675                         return;
 676                     }
 677                     if (!db_expression(&args[nargs])) {
 678                         db_printf("Argument missing\n");
 679                         db_flush_lex();
 680                         return;
 681                     }
 682                     nargs++;
 683                 }
 684                 db_unread_token(t);
 685             }
 686             if (db_read_token() != tRPAREN) {
 687                 db_printf("?\n");
 688                 db_flush_lex();
 689                 return;
 690             }
 691         }
 692         while (nargs < MAXARGS) {
 693             args[nargs++] = 0;
 694         }
 695
 696         retval = (*func)(args[0], args[1], args[2], args[3], args[4],
 697                          args[5], args[6], args[7], args[8], args[9] );
 698         db_printf(" %#n\n", retval);
 699 }
 700
 701 boolean_t
 702 db_option(
 703         char    *modif,
 704         int     option)
 705 {
 706         register char *p;
 707
 708         for (p = modif; *p; p++)
 709             if (*p == option)
 710                 return(TRUE);
 711         return(FALSE);
 712 }