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

     /* 
      * Mach Operating System
      * Copyright (c) 1993,1992,1991,1990 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 "AS IS"
     * 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 Mellon
     * the rights to redistribute these changes.
     */
    /*
     * HISTORY
     * $Log:        db_cond.c,v $
     * Revision 2.5  93/11/17  16:21:26  dbg
     *      Added ANSI function prototypes.
     *      [93/10/08            dbg]
     * 
     * Revision 2.4  92/08/03  17:30:53  jfriedl
     *      removed silly prototypes
     *      [92/08/02            jfriedl]
     * 
     * Revision 2.3  92/05/21  17:06:39  jfriedl
     *      Changed errant call of db_error in db_cond_cmd() to db_printf/db_error.
     *      [92/05/20            jfriedl]
     * 
     * Revision 2.2  91/10/09  15:59:09  af
     *      Created to support conditional break point and command execution.
     *      [91/08/29            tak]
     * 
     */
    
    #include <machine/db_machdep.h>
    #include <machine/setjmp.h>
    
    #include <ddb/db_lex.h>
    #include <ddb/db_break.h>
    #include <ddb/db_command.h>
    #include <ddb/db_output.h>
    
    
    
    #define DB_MAX_COND     10              /* maximum conditions to be set */
    
    int   db_ncond_free = DB_MAX_COND;                      /* free condition */
    struct db_cond {
            int     c_size;                                 /* size of cond */
            char    c_cond_cmd[DB_LEX_LINE_SIZE];           /* cond & cmd */
    } db_cond[DB_MAX_COND];
    
    void
    db_cond_free(
            db_thread_breakpoint_t bkpt)
    {
            if (bkpt->tb_cond > 0) {
                db_cond[bkpt->tb_cond-1].c_size = 0;
                db_ncond_free++;
                bkpt->tb_cond = 0;
            }
    }
    
    boolean_t
    db_cond_check(
            db_thread_breakpoint_t bkpt)
    {
            register  struct db_cond *cp;
            db_expr_t value;
            int       t;
            jmp_buf_t db_jmpbuf;
    
            if (bkpt->tb_cond <= 0)         /* no condition */
                return TRUE;
            db_dot = PC_REGS(DDB_REGS);
            db_prev = db_dot;
            db_next = db_dot;
            if (_setjmp(db_recover = &db_jmpbuf)) {
                /*
                 * in case of error, return true to enter interactive mode
                 */
                return TRUE;
            }
    
            /*
             * switch input, and evaluate condition
             */
           cp = &db_cond[bkpt->tb_cond - 1];
           db_switch_input(cp->c_cond_cmd, cp->c_size);
           if (!db_expression(&value)) {
               db_printf("error: condition evaluation error\n");
               return TRUE;
           }
           if (value == 0 || --(bkpt->tb_count) > 0)
               return FALSE;
   
           /*
            * execute a command list if exist
            */
           bkpt->tb_count = bkpt->tb_init_count;
           if ((t = db_read_token()) != tEOL) {
               db_unread_token(t);
               return(db_exec_cmd_nest(0, 0));
           }
           return TRUE;
   }
   
   void
   db_cond_print(
           db_thread_breakpoint_t bkpt)
   {
           register char *p, *ep;
           register struct db_cond *cp;
   
           if (bkpt->tb_cond <= 0)
               return;
           cp = &db_cond[bkpt->tb_cond-1];
           p = cp->c_cond_cmd;
           ep = p + cp->c_size;
           while (p < ep) {
               if (*p == '\n' || *p == 0)
                   break;
               db_putchar(*p++);
           }
   }
   
   void
   db_cond_cmd()
   {
           register  c;
           register  struct db_cond *cp;
           register  char *p;
           db_expr_t value;
           db_thread_breakpoint_t bkpt;
   
           if (db_read_token() != tHASH || db_read_token() != tNUMBER) {
               db_printf("#<number> expected instead of \"%s\"\n", db_tok_string);
               db_error(0);
               return;
           }
           if ((bkpt = db_find_breakpoint_number(db_tok_number, 0)) == 0) {
               db_printf("No such break point #%d\n", db_tok_number);
               db_error(0);
               return;
           }
           /*
            * if the break point already has a condition, free it first
            */
           if (bkpt->tb_cond > 0) {
               cp = &db_cond[bkpt->tb_cond - 1];
               db_cond_free(bkpt);
           } else {
               if (db_ncond_free <= 0) {
                   db_error("Too many conditions\n");
                   return;
               }
               for (cp = db_cond; cp < &db_cond[DB_MAX_COND]; cp++)
                   if (cp->c_size == 0)
                       break;
               if (cp >= &db_cond[DB_MAX_COND])
                   panic("bad db_cond_free");
           }
           for (c = db_read_char(); c == ' ' || c == '\t'; c = db_read_char());
           for (p = cp->c_cond_cmd; c >= 0; c = db_read_char())
               *p++ = c;
           /*
            * switch to saved data and call db_expression to check the condition.
            * If no condition is supplied, db_expression will return false.
            * In this case, clear previous condition of the break point.
            * If condition is supplied, set the condition to the permanent area.
            * Note: db_expression will not return here, if the condition
            *       expression is wrong.
            */
           db_switch_input(cp->c_cond_cmd, p - cp->c_cond_cmd);
           if (!db_expression(&value)) {
               /* since condition is already freed, do nothing */
               db_flush_lex();
               return;
           }
           db_flush_lex();
           db_ncond_free--;
           cp->c_size = p - cp->c_cond_cmd;
           bkpt->tb_cond = (cp - db_cond) + 1;
   }

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