FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_command.c

     /*-
      * Mach Operating System
      * Copyright (c) 1991,1990 Carnegie Mellon University
      * All Rights Reserved.
      *
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
      * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     *
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     *
     * Carnegie Mellon requests users of this software to return to
     *
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     *
     * any improvements or extensions that they make and grant Carnegie the
     * rights to redistribute these changes.
     */
    /*
     *      Author: David B. Golub, Carnegie Mellon University
     *      Date:   7/90
     */
    /*
     * Command dispatcher.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.4/sys/ddb/db_command.c 221939 2011-05-15 01:08:51Z attilio $");
    
    #include <sys/param.h>
    #include <sys/linker_set.h>
    #include <sys/lock.h>
    #include <sys/kdb.h>
    #include <sys/mutex.h>
    #include <sys/proc.h>
    #include <sys/reboot.h>
    #include <sys/signalvar.h>
    #include <sys/systm.h>
    #include <sys/cons.h>
    #include <sys/watchdog.h>
    #include <sys/kernel.h>
    
    #include <ddb/ddb.h>
    #include <ddb/db_command.h>
    #include <ddb/db_lex.h>
    #include <ddb/db_output.h>
    
    #include <machine/cpu.h>
    #include <machine/setjmp.h>
    
    /*
     * Exported global variables
     */
    boolean_t       db_cmd_loop_done;
    db_addr_t       db_dot;
    db_addr_t       db_last_addr;
    db_addr_t       db_prev;
    db_addr_t       db_next;
    
    static db_cmdfcn_t      db_fncall;
    static db_cmdfcn_t      db_gdb;
    static db_cmdfcn_t      db_halt;
    static db_cmdfcn_t      db_kill;
    static db_cmdfcn_t      db_reset;
    static db_cmdfcn_t      db_stack_trace;
    static db_cmdfcn_t      db_stack_trace_all;
    static db_cmdfcn_t      db_watchdog;
    
    /*
     * 'show' commands
     */
    
    static struct command db_show_all_cmds[] = {
            { "trace",      db_stack_trace_all,     0,      0 },
    };
    struct command_table db_show_all_table =
        LIST_HEAD_INITIALIZER(db_show_all_table);
    
    static struct command db_show_cmds[] = {
            { "all",        0,                      0,      &db_show_all_table },
            { "registers",  db_show_regs,           0,      0 },
            { "breaks",     db_listbreak_cmd,       0,      0 },
            { "threads",    db_show_threads,        0,      0 },
    };
    struct command_table db_show_table = LIST_HEAD_INITIALIZER(db_show_table);
    
    static struct command db_cmds[] = {
            { "print",      db_print_cmd,           0,      0 },
            { "p",          db_print_cmd,           0,      0 },
            { "examine",    db_examine_cmd,         CS_SET_DOT, 0 },
            { "x",          db_examine_cmd,         CS_SET_DOT, 0 },
            { "search",     db_search_cmd,          CS_OWN|CS_SET_DOT, 0 },
           { "set",        db_set_cmd,             CS_OWN, 0 },
           { "write",      db_write_cmd,           CS_MORE|CS_SET_DOT, 0 },
           { "w",          db_write_cmd,           CS_MORE|CS_SET_DOT, 0 },
           { "delete",     db_delete_cmd,          0,      0 },
           { "d",          db_delete_cmd,          0,      0 },
           { "break",      db_breakpoint_cmd,      0,      0 },
           { "b",          db_breakpoint_cmd,      0,      0 },
           { "dwatch",     db_deletewatch_cmd,     0,      0 },
           { "watch",      db_watchpoint_cmd,      CS_MORE,0 },
           { "dhwatch",    db_deletehwatch_cmd,    0,      0 },
           { "hwatch",     db_hwatchpoint_cmd,     0,      0 },
           { "step",       db_single_step_cmd,     0,      0 },
           { "s",          db_single_step_cmd,     0,      0 },
           { "continue",   db_continue_cmd,        0,      0 },
           { "c",          db_continue_cmd,        0,      0 },
           { "until",      db_trace_until_call_cmd,0,      0 },
           { "next",       db_trace_until_matching_cmd,0,  0 },
           { "match",      db_trace_until_matching_cmd,0,  0 },
           { "trace",      db_stack_trace,         CS_OWN, 0 },
           { "t",          db_stack_trace,         CS_OWN, 0 },
           /* XXX alias for all trace */
           { "alltrace",   db_stack_trace_all,     0,      0 },
           { "where",      db_stack_trace,         CS_OWN, 0 },
           { "bt",         db_stack_trace,         CS_OWN, 0 },
           { "call",       db_fncall,              CS_OWN, 0 },
           { "show",       0,                      0,      &db_show_table },
           { "ps",         db_ps,                  0,      0 },
           { "gdb",        db_gdb,                 0,      0 },
           { "halt",       db_halt,                0,      0 },
           { "reboot",     db_reset,               0,      0 },
           { "reset",      db_reset,               0,      0 },
           { "kill",       db_kill,                CS_OWN, 0 },
           { "watchdog",   db_watchdog,            CS_OWN, 0 },
           { "thread",     db_set_thread,          CS_OWN, 0 },
           { "run",        db_run_cmd,             CS_OWN, 0 },
           { "script",     db_script_cmd,          CS_OWN, 0 },
           { "scripts",    db_scripts_cmd,         0,      0 },
           { "unscript",   db_unscript_cmd,        CS_OWN, 0 },
           { "capture",    db_capture_cmd,         CS_OWN, 0 },
           { "textdump",   db_textdump_cmd,        CS_OWN, 0 },
   };
   struct command_table db_cmd_table = LIST_HEAD_INITIALIZER(db_cmd_table);
   
   static struct command   *db_last_command = 0;
   
   /*
    * if 'ed' style: 'dot' is set at start of last item printed,
    * and '+' points to next line.
    * Otherwise: 'dot' points to next item, '..' points to last.
    */
   static boolean_t        db_ed_style = TRUE;
   
   /*
    * Utility routine - discard tokens through end-of-line.
    */
   void
   db_skip_to_eol()
   {
           int     t;
           do {
               t = db_read_token();
           } while (t != tEOL);
   }
   
   /*
    * Results of command search.
    */
   #define CMD_UNIQUE      0
   #define CMD_FOUND       1
   #define CMD_NONE        2
   #define CMD_AMBIGUOUS   3
   #define CMD_HELP        4
   
   static void     db_cmd_match(char *name, struct command *cmd,
                       struct command **cmdp, int *resultp);
   static void     db_cmd_list(struct command_table *table);
   static int      db_cmd_search(char *name, struct command_table *table,
                       struct command **cmdp);
   static void     db_command(struct command **last_cmdp,
                       struct command_table *cmd_table, int dopager);
   
   /*
    * Initialize the command lists from the static tables.
    */
   void
   db_command_init(void)
   {
   #define N(a)    (sizeof(a) / sizeof(a[0]))
           int i;
   
           for (i = 0; i < N(db_cmds); i++)
                   db_command_register(&db_cmd_table, &db_cmds[i]);
           for (i = 0; i < N(db_show_cmds); i++)
                   db_command_register(&db_show_table, &db_show_cmds[i]);
           for (i = 0; i < N(db_show_all_cmds); i++)
                   db_command_register(&db_show_all_table, &db_show_all_cmds[i]);
   #undef N
   }
   
   /*
    * Register a command.
    */
   void
   db_command_register(struct command_table *list, struct command *cmd)
   {
           struct command *c, *last;
   
           last = NULL;
           LIST_FOREACH(c, list, next) {
                   int n = strcmp(cmd->name, c->name);
   
                   /* Check that the command is not already present. */
                   if (n == 0) {
                           printf("%s: Warning, the command \"%s\" already exists;"
                                " ignoring request\n", __func__, cmd->name);
                           return;
                   }
                   if (n < 0) {
                           /* NB: keep list sorted lexicographically */
                           LIST_INSERT_BEFORE(c, cmd, next);
                           return;
                   }
                   last = c;
           }
           if (last == NULL)
                   LIST_INSERT_HEAD(list, cmd, next);
           else
                   LIST_INSERT_AFTER(last, cmd, next);
   }
   
   /*
    * Remove a command previously registered with db_command_register.
    */
   void
   db_command_unregister(struct command_table *list, struct command *cmd)
   {
           struct command *c;
   
           LIST_FOREACH(c, list, next) {
                   if (cmd == c) {
                           LIST_REMOVE(cmd, next);
                           return;
                   }
           }
           /* NB: intentionally quiet */
   }
   
   /*
    * Helper function to match a single command.
    */
   static void
   db_cmd_match(name, cmd, cmdp, resultp)
           char *          name;
           struct command  *cmd;
           struct command  **cmdp; /* out */
           int *           resultp;
   {
           char *lp, *rp;
           int c;
   
           lp = name;
           rp = cmd->name;
           while ((c = *lp) == *rp) {
                   if (c == 0) {
                           /* complete match */
                           *cmdp = cmd;
                           *resultp = CMD_UNIQUE;
                           return;
                   }
                   lp++;
                   rp++;
           }
           if (c == 0) {
                   /* end of name, not end of command -
                      partial match */
                   if (*resultp == CMD_FOUND) {
                           *resultp = CMD_AMBIGUOUS;
                           /* but keep looking for a full match -
                              this lets us match single letters */
                   } else {
                           *cmdp = cmd;
                           *resultp = CMD_FOUND;
                   }
           }
   }
   
   /*
    * Search for command prefix.
    */
   static int
   db_cmd_search(name, table, cmdp)
           char *          name;
           struct command_table *table;
           struct command  **cmdp; /* out */
   {
           struct command  *cmd;
           int             result = CMD_NONE;
   
           LIST_FOREACH(cmd, table, next) {
                   db_cmd_match(name,cmd,cmdp,&result);
                   if (result == CMD_UNIQUE)
                           break;
           }
   
           if (result == CMD_NONE) {
                   /* check for 'help' */
                   if (name[0] == 'h' && name[1] == 'e'
                       && name[2] == 'l' && name[3] == 'p')
                           result = CMD_HELP;
           }
           return (result);
   }
   
   static void
   db_cmd_list(table)
           struct command_table *table;
   {
           register struct command *cmd;
   
           LIST_FOREACH(cmd, table, next) {
                   db_printf("%-12s", cmd->name);
                   db_end_line(12);
           }
   }
   
   static void
   db_command(last_cmdp, cmd_table, dopager)
           struct command  **last_cmdp;    /* IN_OUT */
           struct command_table *cmd_table;
           int dopager;
   {
           struct command  *cmd = NULL;
           int             t;
           char            modif[TOK_STRING_SIZE];
           db_expr_t       addr, count;
           boolean_t       have_addr = FALSE;
           int             result;
   
           t = db_read_token();
           if (t == tEOL) {
               /* empty line repeats last command, at 'next' */
               cmd = *last_cmdp;
               addr = (db_expr_t)db_next;
               have_addr = FALSE;
               count = 1;
               modif[0] = '\0';
           }
           else if (t == tEXCL) {
               db_fncall((db_expr_t)0, (boolean_t)0, (db_expr_t)0, (char *)0);
               return;
           }
           else if (t != tIDENT) {
               db_printf("?\n");
               db_flush_lex();
               return;
           }
           else {
               /*
                * Search for command
                */
               while (cmd_table) {
                   result = db_cmd_search(db_tok_string,
                                          cmd_table,
                                          &cmd);
                   switch (result) {
                       case CMD_NONE:
                           db_printf("No such command\n");
                           db_flush_lex();
                           return;
                       case CMD_AMBIGUOUS:
                           db_printf("Ambiguous\n");
                           db_flush_lex();
                           return;
                       case CMD_HELP:
                           db_cmd_list(cmd_table);
                           db_flush_lex();
                           return;
                       default:
                           break;
                   }
                   if ((cmd_table = cmd->more) != NULL) {
                       t = db_read_token();
                       if (t != tIDENT) {
                           db_cmd_list(cmd_table);
                           db_flush_lex();
                           return;
                       }
                   }
               }
   
               if ((cmd->flag & CS_OWN) == 0) {
                   /*
                    * Standard syntax:
                    * command [/modifier] [addr] [,count]
                    */
                   t = db_read_token();
                   if (t == tSLASH) {
                       t = db_read_token();
                       if (t != tIDENT) {
                           db_printf("Bad modifier\n");
                           db_flush_lex();
                           return;
                       }
                       db_strcpy(modif, db_tok_string);
                   }
                   else {
                       db_unread_token(t);
                       modif[0] = '\0';
                   }
   
                   if (db_expression(&addr)) {
                       db_dot = (db_addr_t) addr;
                       db_last_addr = db_dot;
                       have_addr = TRUE;
                   }
                   else {
                       addr = (db_expr_t) db_dot;
                       have_addr = FALSE;
                   }
                   t = db_read_token();
                   if (t == tCOMMA) {
                       if (!db_expression(&count)) {
                           db_printf("Count missing\n");
                           db_flush_lex();
                           return;
                       }
                   }
                   else {
                       db_unread_token(t);
                       count = -1;
                   }
                   if ((cmd->flag & CS_MORE) == 0) {
                       db_skip_to_eol();
                   }
               }
           }
           *last_cmdp = cmd;
           if (cmd != 0) {
               /*
                * Execute the command.
                */
               if (dopager)
                   db_enable_pager();
               else
                   db_disable_pager();
               (*cmd->fcn)(addr, have_addr, count, modif);
               if (dopager)
                   db_disable_pager();
   
               if (cmd->flag & CS_SET_DOT) {
                   /*
                    * If command changes dot, set dot to
                    * previous address displayed (if 'ed' style).
                    */
                   if (db_ed_style) {
                       db_dot = db_prev;
                   }
                   else {
                       db_dot = db_next;
                   }
               }
               else {
                   /*
                    * If command does not change dot,
                    * set 'next' location to be the same.
                    */
                   db_next = db_dot;
               }
           }
   }
   
   /*
    * At least one non-optional command must be implemented using
    * DB_COMMAND() so that db_cmd_set gets created.  Here is one.
    */
   DB_COMMAND(panic, db_panic)
   {
           db_disable_pager();
           panic("from debugger");
   }
   
   void
   db_command_loop()
   {
           /*
            * Initialize 'prev' and 'next' to dot.
            */
           db_prev = db_dot;
           db_next = db_dot;
   
           db_cmd_loop_done = 0;
           while (!db_cmd_loop_done) {
               if (db_print_position() != 0)
                   db_printf("\n");
   
               db_printf("db> ");
               (void) db_read_line();
   
               db_command(&db_last_command, &db_cmd_table, /* dopager */ 1);
           }
   }
   
   /*
    * Execute a command on behalf of a script.  The caller is responsible for
    * making sure that the command string is < DB_MAXLINE or it will be
    * truncated.
    *
    * XXXRW: Runs by injecting faked input into DDB input stream; it would be
    * nicer to use an alternative approach that didn't mess with the previous
    * command buffer.
    */
   void
   db_command_script(const char *command)
   {
           db_prev = db_next = db_dot;
           db_inject_line(command);
           db_command(&db_last_command, &db_cmd_table, /* dopager */ 0);
   }
   
   void
   db_error(s)
           const char *s;
   {
           if (s)
               db_printf("%s", s);
           db_flush_lex();
           kdb_reenter();
   }
   
   
   /*
    * Call random function:
    * !expr(arg,arg,arg)
    */
   
   /* The generic implementation supports a maximum of 10 arguments. */
   typedef db_expr_t __db_f(db_expr_t, db_expr_t, db_expr_t, db_expr_t,
       db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t, db_expr_t);
   
   static __inline int
   db_fncall_generic(db_expr_t addr, db_expr_t *rv, int nargs, db_expr_t args[])
   {
           __db_f *f = (__db_f *)addr;
   
           if (nargs > 10) {
                   db_printf("Too many arguments (max 10)\n");
                   return (0);
           }
           *rv = (*f)(args[0], args[1], args[2], args[3], args[4], args[5],
               args[6], args[7], args[8], args[9]);
           return (1);
   }
   
   static void
   db_fncall(dummy1, dummy2, dummy3, dummy4)
           db_expr_t       dummy1;
           boolean_t       dummy2;
           db_expr_t       dummy3;
           char *          dummy4;
   {
           db_expr_t       fn_addr;
           db_expr_t       args[DB_MAXARGS];
           int             nargs = 0;
           db_expr_t       retval;
           int             t;
   
           if (!db_expression(&fn_addr)) {
               db_printf("Bad function\n");
               db_flush_lex();
               return;
           }
   
           t = db_read_token();
           if (t == tLPAREN) {
               if (db_expression(&args[0])) {
                   nargs++;
                   while ((t = db_read_token()) == tCOMMA) {
                       if (nargs == DB_MAXARGS) {
                           db_printf("Too many arguments (max %d)\n", DB_MAXARGS);
                           db_flush_lex();
                           return;
                       }
                       if (!db_expression(&args[nargs])) {
                           db_printf("Argument missing\n");
                           db_flush_lex();
                           return;
                       }
                       nargs++;
                   }
                   db_unread_token(t);
               }
               if (db_read_token() != tRPAREN) {
                   db_printf("?\n");
                   db_flush_lex();
                   return;
               }
           }
           db_skip_to_eol();
           db_disable_pager();
   
           if (DB_CALL(fn_addr, &retval, nargs, args))
                   db_printf("= %#lr\n", (long)retval);
   }
   
   static void
   db_halt(db_expr_t dummy, boolean_t dummy2, db_expr_t dummy3, char *dummy4)
   {
   
           cpu_halt();
   }
   
   static void
   db_kill(dummy1, dummy2, dummy3, dummy4)
           db_expr_t       dummy1;
           boolean_t       dummy2;
           db_expr_t       dummy3;
           char *          dummy4;
   {
           db_expr_t old_radix, pid, sig;
           struct proc *p;
   
   #define DB_ERROR(f)     do { db_printf f; db_flush_lex(); goto out; } while (0)
   
           /*
            * PIDs and signal numbers are typically represented in base
            * 10, so make that the default here.  It can, of course, be
            * overridden by specifying a prefix.
            */
           old_radix = db_radix;
           db_radix = 10;
           /* Retrieve arguments. */
           if (!db_expression(&sig))
                   DB_ERROR(("Missing signal number\n"));
           if (!db_expression(&pid))
                   DB_ERROR(("Missing process ID\n"));
           db_skip_to_eol();
           if (!_SIG_VALID(sig))
                   DB_ERROR(("Signal number out of range\n"));
   
           /*
            * Find the process in question.  allproc_lock is not needed
            * since we're in DDB.
            */
           /* sx_slock(&allproc_lock); */
           FOREACH_PROC_IN_SYSTEM(p)
               if (p->p_pid == pid)
                       break;
           /* sx_sunlock(&allproc_lock); */
           if (p == NULL)
                   DB_ERROR(("Can't find process with pid %ld\n", (long) pid));
   
           /* If it's already locked, bail; otherwise, do the deed. */
           if (PROC_TRYLOCK(p) == 0)
                   DB_ERROR(("Can't lock process with pid %ld\n", (long) pid));
           else {
                   pksignal(p, sig, NULL);
                   PROC_UNLOCK(p);
           }
   
   out:
           db_radix = old_radix;
   #undef DB_ERROR
   }
   
   /*
    * Reboot.  In case there is an additional argument, take it as delay in
    * seconds.  Default to 15s if we cannot parse it and make sure we will
    * never wait longer than 1 week.  Some code is similar to
    * kern_shutdown.c:shutdown_panic().
    */
   #ifndef DB_RESET_MAXDELAY
   #define DB_RESET_MAXDELAY       (3600 * 24 * 7)
   #endif
   
   static void
   db_reset(db_expr_t addr, boolean_t have_addr, db_expr_t count __unused,
       char *modif __unused)
   {
           int delay, loop;
   
           if (have_addr) {
                   delay = (int)db_hex2dec(addr);
   
                   /* If we parse to fail, use 15s. */
                   if (delay == -1)
                           delay = 15;
   
                   /* Cap at one week. */
                   if ((uintmax_t)delay > (uintmax_t)DB_RESET_MAXDELAY)
                           delay = DB_RESET_MAXDELAY;
   
                   db_printf("Automatic reboot in %d seconds - "
                       "press a key on the console to abort\n", delay);
                   for (loop = delay * 10; loop > 0; --loop) {
                           DELAY(1000 * 100); /* 1/10th second */
                           /* Did user type a key? */
                           if (cncheckc() != -1)
                                   return;
                   }
           }
   
           cpu_reset();
   }
   
   static void
   db_watchdog(dummy1, dummy2, dummy3, dummy4)
           db_expr_t       dummy1;
           boolean_t       dummy2;
           db_expr_t       dummy3;
           char *          dummy4;
   {
           db_expr_t old_radix, tout;
           int err, i;
   
           old_radix = db_radix;
           db_radix = 10;
           err = db_expression(&tout);
           db_skip_to_eol();
           db_radix = old_radix;
   
           /* If no argument is provided the watchdog will just be disabled. */
           if (err == 0) {
                   db_printf("No argument provided, disabling watchdog\n");
                   tout = 0;
           } else if ((tout & WD_INTERVAL) == WD_TO_NEVER) {
                   db_error("Out of range watchdog interval\n");
                   return;
           }
           EVENTHANDLER_INVOKE(watchdog_list, tout, &i);
   }
   
   static void
   db_gdb(db_expr_t dummy1, boolean_t dummy2, db_expr_t dummy3, char *dummy4)
   {
   
           if (kdb_dbbe_select("gdb") != 0) {
                   db_printf("The remote GDB backend could not be selected.\n");
                   return;
           }
           /*
            * Mark that we are done in the debugger.  kdb_trap()
            * should re-enter with the new backend.
            */
           db_cmd_loop_done = 1;
           db_printf("(ctrl-c will return control to ddb)\n");
   }
   
   static void
   db_stack_trace(db_expr_t tid, boolean_t hastid, db_expr_t count, char *modif)
   {
           struct thread *td;
           db_expr_t radix;
           pid_t pid;
           int t;
   
           /*
            * We parse our own arguments. We don't like the default radix.
            */
           radix = db_radix;
           db_radix = 10;
           hastid = db_expression(&tid);
           t = db_read_token();
           if (t == tCOMMA) {
                   if (!db_expression(&count)) {
                           db_printf("Count missing\n");
                           db_flush_lex();
                           return;
                   }
           } else {
                   db_unread_token(t);
                   count = -1;
           }
           db_skip_to_eol();
           db_radix = radix;
   
           if (hastid) {
                   td = kdb_thr_lookup((lwpid_t)tid);
                   if (td == NULL)
                           td = kdb_thr_from_pid((pid_t)tid);
                   if (td == NULL) {
                           db_printf("Thread %d not found\n", (int)tid);
                           return;
                   }
           } else
                   td = kdb_thread;
           if (td->td_proc != NULL)
                   pid = td->td_proc->p_pid;
           else
                   pid = -1;
           db_printf("Tracing pid %d tid %ld td %p\n", pid, (long)td->td_tid, td);
           db_trace_thread(td, count);
   }
   
   static void
   db_stack_trace_all(db_expr_t dummy, boolean_t dummy2, db_expr_t dummy3,
       char *dummy4)
   {
           struct proc *p;
           struct thread *td;
           jmp_buf jb;
           void *prev_jb;
   
           FOREACH_PROC_IN_SYSTEM(p) {
                   prev_jb = kdb_jmpbuf(jb);
                   if (setjmp(jb) == 0) {
                           FOREACH_THREAD_IN_PROC(p, td) {
                                   db_printf("\nTracing command %s pid %d tid %ld td %p\n",
                                             p->p_comm, p->p_pid, (long)td->td_tid, td);
                                   db_trace_thread(td, -1);
                                   if (db_pager_quit) {
                                           kdb_jmpbuf(prev_jb);
                                           return;
                                   }
                           }
                   }
                   kdb_jmpbuf(prev_jb);
           }
   }
   
   /*
    * Take the parsed expression value from the command line that was parsed
    * as a hexadecimal value and convert it as if the expression was parsed
    * as a decimal value.  Returns -1 if the expression was not a valid
    * decimal value.
    */
   db_expr_t
   db_hex2dec(db_expr_t expr)
   {
           uintptr_t x, y;
           db_expr_t val;
   
           y = 1;
           val = 0;
           x = expr;
           while (x != 0) {
                   if (x % 16 > 9)
                           return (-1);
                   val += (x % 16) * (y);
                   x >>= 4;
                   y *= 10;
           }
           return (val);
   }

Cache object: 7af1fe7606b6587753c10182c279532c