debugger/break.c

   1 /*
   2  * Debugger break-points handling
   3  *
   4  * Copyright 1994 Martin von Loewis
   5  * Copyright 1995 Alexandre Julliard
   6  * Copyright 1999,2000 Eric Pouech
   7  */
   8
   9 #include "config.h"
  10 #include "debugger.h"
  11
  12 #ifdef __i386__
  13 #define DR7_CONTROL_SHIFT       16
  14 #define DR7_CONTROL_SIZE        4
  15
  16 #define DR7_RW_EXECUTE          (0x0)
  17 #define DR7_RW_WRITE            (0x1)
  18 #define DR7_RW_READ             (0x3)
  19
  20 #define DR7_LEN_1               (0x0)
  21 #define DR7_LEN_2               (0x4)
  22 #define DR7_LEN_4               (0xC)
  23
  24 #define DR7_LOCAL_ENABLE_SHIFT  0
  25 #define DR7_GLOBAL_ENABLE_SHIFT 1
  26 #define DR7_ENABLE_SIZE         2
  27
  28 #define DR7_LOCAL_ENABLE_MASK   (0x55)
  29 #define DR7_GLOBAL_ENABLE_MASK  (0xAA)
  30
  31 #define DR7_CONTROL_RESERVED    (0xFC00)
  32 #define DR7_LOCAL_SLOWDOWN      (0x100)
  33 #define DR7_GLOBAL_SLOWDOWN     (0x200)
  34
  35 #define DR7_ENABLE_MASK(dr)     (1<<(DR7_LOCAL_ENABLE_SHIFT+DR7_ENABLE_SIZE*(dr)))
  36 #define IS_DR7_SET(ctrl,dr)     ((ctrl)&DR7_ENABLE_MASK(dr))
  37 #define INT3          0xcc   /* int 3 opcode */
  38 #endif
  39
  40 #define MAX_BREAKPOINTS 100
  41
  42 static DBG_BREAKPOINT breakpoints[MAX_BREAKPOINTS];
  43
  44 static int next_bp = 1;  /* breakpoint 0 is reserved for step-over */
  45
  46 /***********************************************************************
  47  *           DEBUG_IsStepOverInstr
  48  *
  49  * Determine if the instruction at CS:EIP is an instruction that
  50  * we need to step over (like a call or a repetitive string move).
  51  */
  52 static BOOL DEBUG_IsStepOverInstr(void)
  53 {
  54 #ifdef __i386__
  55     BYTE*       instr;
  56     BYTE        ch;
  57     DBG_ADDR    addr;
  58
  59     addr.seg = DEBUG_context.SegCs;
  60     addr.off = DEBUG_context.Eip;
  61     /* FIXME: old code was using V86BASE(DEBUG_context)
  62      * instead of passing thru DOSMEM_MemoryBase
  63      */
  64     instr = (BYTE*)DEBUG_ToLinear(&addr);
  65
  66     for (;;)
  67     {
  68         if (!DEBUG_READ_MEM(instr, &ch, sizeof(ch)))
  69             return FALSE;
  70
  71         switch (ch)
  72         {
  73           /* Skip all prefixes */
  74
  75         case 0x2e:  /* cs: */
  76         case 0x36:  /* ss: */
  77         case 0x3e:  /* ds: */
  78         case 0x26:  /* es: */
  79         case 0x64:  /* fs: */
  80         case 0x65:  /* gs: */
  81         case 0x66:  /* opcode size prefix */
  82         case 0x67:  /* addr size prefix */
  83         case 0xf0:  /* lock */
  84         case 0xf2:  /* repne */
  85         case 0xf3:  /* repe */
  86             instr++;
  87             continue;
  88
  89           /* Handle call instructions */
  90
  91         case 0xcd:  /* int <intno> */
  92         case 0xe8:  /* call <offset> */
  93         case 0x9a:  /* lcall <seg>:<off> */
  94             return TRUE;
  95
  96         case 0xff:  /* call <regmodrm> */
  97             if (!DEBUG_READ_MEM(instr + 1, &ch, sizeof(ch)))
  98                 return FALSE;
  99             return (((ch & 0x38) == 0x10) || ((ch & 0x38) == 0x18));
 100
 101           /* Handle string instructions */
 102
 103         case 0x6c:  /* insb */
 104         case 0x6d:  /* insw */
 105         case 0x6e:  /* outsb */
 106         case 0x6f:  /* outsw */
 107         case 0xa4:  /* movsb */
 108         case 0xa5:  /* movsw */
 109         case 0xa6:  /* cmpsb */
 110         case 0xa7:  /* cmpsw */
 111         case 0xaa:  /* stosb */
 112         case 0xab:  /* stosw */
 113         case 0xac:  /* lodsb */
 114         case 0xad:  /* lodsw */
 115         case 0xae:  /* scasb */
 116         case 0xaf:  /* scasw */
 117             return TRUE;
 118
 119         default:
 120             return FALSE;
 121         }
 122     }
 123 #else
 124     return FALSE;
 125 #endif
 126 }
 127
 128
 129 /***********************************************************************
 130  *           DEBUG_IsFctReturn
 131  *
 132  * Determine if the instruction at CS:EIP is an instruction that
 133  * is a function return.
 134  */
 135 BOOL DEBUG_IsFctReturn(void)
 136 {
 137 #ifdef __i386__
 138     BYTE*       instr;
 139     BYTE        ch;
 140     DBG_ADDR    addr;
 141
 142     addr.seg = DEBUG_context.SegCs;
 143     addr.off = DEBUG_context.Eip;
 144     /* FIXME: old code was using V86BASE(DEBUG_context)
 145      * instead of passing thru DOSMEM_MemoryBase
 146      */
 147     instr = (BYTE*)DEBUG_ToLinear(&addr);
 148
 149     if (!DEBUG_READ_MEM(instr, &ch, sizeof(ch)))
 150         return FALSE;
 151
 152     return (ch == 0xc2) || (ch == 0xc3);
 153 #else
 154     return FALSE;
 155 #endif
 156 }
 157
 158
 159 /***********************************************************************
 160  *           DEBUG_SetBreakpoints
 161  *
 162  * Set or remove all the breakpoints.
 163  */
 164 void DEBUG_SetBreakpoints( BOOL set )
 165 {
 166    int          i;
 167
 168 #ifdef __i386__
 169    DEBUG_context.Dr7 &= ~DR7_LOCAL_ENABLE_MASK;
 170 #endif
 171
 172    for (i = 0; i < next_bp; i++)
 173    {
 174       if (!(breakpoints[i].refcount && breakpoints[i].enabled))
 175          continue;
 176
 177       switch (breakpoints[i].type) {
 178       case DBG_BREAK:
 179          {
 180 #ifdef __i386__
 181             char ch = set ? INT3 : breakpoints[i].u.b.opcode;
 182 #endif
 183
 184             if (!DEBUG_WRITE_MEM( (void*)DEBUG_ToLinear(&breakpoints[i].addr),
 185                                   &ch, sizeof(ch) ))
 186             {
 187                DEBUG_Printf(DBG_CHN_MESG, "Invalid address for breakpoint %d, disabling it\n", i);
 188                breakpoints[i].enabled = FALSE;
 189             }
 190          }
 191          break;
 192       case DBG_WATCH:
 193          if (set)
 194          {
 195 #ifdef __i386__
 196             DWORD       bits;
 197             int         reg = breakpoints[i].u.w.reg;
 198             LPDWORD     lpdr = NULL;
 199
 200             switch (reg)
 201             {
 202                case 0: lpdr = &DEBUG_context.Dr0; break;
 203                case 1: lpdr = &DEBUG_context.Dr1; break;
 204                case 2: lpdr = &DEBUG_context.Dr2; break;
 205                case 3: lpdr = &DEBUG_context.Dr3; break;
 206                default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 207             }
 208
 209             *lpdr = DEBUG_ToLinear(&breakpoints[i].addr);
 210             bits = (breakpoints[i].u.w.rw) ? DR7_RW_WRITE : DR7_RW_READ;
 211             switch (breakpoints[i].u.w.len + 1)
 212             {
 213                case 4: bits |= DR7_LEN_4;       break;
 214                case 2: bits |= DR7_LEN_2;       break;
 215                case 1: bits |= DR7_LEN_1;       break;
 216                default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 217             }
 218
 219             DEBUG_context.Dr7 &= ~(0x0F << (DR7_CONTROL_SHIFT + DR7_CONTROL_SIZE * reg));
 220             DEBUG_context.Dr7 |= bits << (DR7_CONTROL_SHIFT + DR7_CONTROL_SIZE * reg);
 221             DEBUG_context.Dr7 |= DR7_ENABLE_MASK(reg) | DR7_LOCAL_SLOWDOWN;
 222 #endif
 223          }
 224          break;
 225       }
 226    }
 227 }
 228
 229 /***********************************************************************
 230  *           DEBUG_FindBreakpoint
 231  *
 232  * Find the breakpoint for a given address. Return the breakpoint
 233  * number or -1 if none.
 234  * If type is DBG_BREAKPOINT, addr is a complete addr
 235  * If type is DBG_WATCHPOINT, only addr.off is meaningful and contains
 236  * linear address
 237  */
 238 static int DEBUG_FindBreakpoint( const DBG_ADDR *addr, int type )
 239 {
 240    int i;
 241
 242    for (i = 0; i < next_bp; i++)
 243    {
 244       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 245           breakpoints[i].type == type )
 246       {
 247          if ((type == DBG_BREAK &&
 248               breakpoints[i].addr.seg == addr->seg &&
 249               breakpoints[i].addr.off == addr->off) ||
 250              (type == DBG_WATCH &&
 251               DEBUG_ToLinear(&breakpoints[i].addr) == addr->off))
 252             return i;
 253       }
 254    }
 255    return -1;
 256 }
 257
 258 /***********************************************************************
 259  *           DEBUG_InitXPoint
 260  *
 261  * Find an empty slot in BP table to add a new break/watch point
 262  */
 263 static  int     DEBUG_InitXPoint(int type, DBG_ADDR* addr)
 264 {
 265    int  num;
 266
 267    for (num = (next_bp < MAX_BREAKPOINTS) ? next_bp++ : 1;
 268         num < MAX_BREAKPOINTS; num++)
 269    {
 270       if (breakpoints[num].refcount == 0)
 271       {
 272          breakpoints[num].refcount = 1;
 273          breakpoints[num].enabled = TRUE;
 274          breakpoints[num].type    = type;
 275          breakpoints[num].skipcount = 0;
 276          breakpoints[num].addr = *addr;
 277          breakpoints[num].is32 = 1;
 278 #ifdef __i386__
 279          if (addr->seg)
 280          {
 281             switch (DEBUG_GetSelectorType( addr->seg ))
 282             {
 283                case 32: break;
 284                case 16: breakpoints[num].is32 = 0; break;
 285                default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 286             }
 287          }
 288 #endif
 289          return num;
 290       }
 291    }
 292
 293    DEBUG_Printf( DBG_CHN_MESG, "Too many breakpoints. Please delete some.\n" );
 294    return -1;
 295 }
 296
 297 /***********************************************************************
 298  *           DEBUG_GetWatchedValue
 299  *
 300  * Returns the value watched by watch point 'num'.
 301  */
 302 static  BOOL    DEBUG_GetWatchedValue( int num, LPDWORD val )
 303 {
 304    BYTE         buf[4];
 305
 306    if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&breakpoints[num].addr),
 307                        buf, breakpoints[num].u.w.len + 1))
 308       return FALSE;
 309
 310    switch (breakpoints[num].u.w.len + 1)
 311    {
 312       case 4:   *val = *(DWORD*)buf;    break;
 313       case 2:   *val = *(WORD*)buf;     break;
 314       case 1:   *val = *(BYTE*)buf;     break;
 315       default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 316    }
 317    return TRUE;
 318 }
 319
 320 /***********************************************************************
 321  *           DEBUG_AddBreakpoint
 322  *
 323  * Add a breakpoint.
 324  */
 325 void DEBUG_AddBreakpoint( const DBG_VALUE *_value, BOOL (*func)(void) )
 326 {
 327     DBG_VALUE value = *_value;
 328     int num;
 329     unsigned int seg2;
 330     BYTE ch;
 331
 332     assert(_value->cookie == DV_TARGET || _value->cookie == DV_HOST);
 333
 334     DEBUG_FixAddress( &value.addr, DEBUG_context.SegCs );
 335
 336     if( value.type != NULL && value.type == DEBUG_TypeIntConst )
 337     {
 338        /*
 339         * We know that we have the actual offset stored somewhere
 340         * else in 32-bit space.  Grab it, and we
 341         * should be all set.
 342         */
 343        seg2 = value.addr.seg;
 344        value.addr.seg = 0;
 345        value.addr.off = DEBUG_GetExprValue(&value, NULL);
 346        value.addr.seg = seg2;
 347     }
 348
 349     if ((num = DEBUG_FindBreakpoint(&value.addr, DBG_BREAK)) >= 1)
 350     {
 351        breakpoints[num].refcount++;
 352        return;
 353     }
 354
 355     if (!DEBUG_READ_MEM_VERBOSE((void*)DEBUG_ToLinear( &value.addr ), &ch, sizeof(ch)))
 356         return;
 357
 358     if ((num = DEBUG_InitXPoint(DBG_BREAK, &value.addr)) == -1)
 359        return;
 360
 361     breakpoints[num].u.b.opcode = ch;
 362     breakpoints[num].u.b.func = func;
 363
 364     DEBUG_Printf( DBG_CHN_MESG, "Breakpoint %d at ", num );
 365     DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? 32 : 16,
 366                         TRUE );
 367     DEBUG_Printf( DBG_CHN_MESG, "\n" );
 368 }
 369
 370
 371  /***********************************************************************
 372  *           DEBUG_AddWatchpoint
 373  *
 374  * Add a watchpoint.
 375  */
 376 void DEBUG_AddWatchpoint( const DBG_VALUE *_value, BOOL is_write )
 377 {
 378    DBG_VALUE    value = *_value;
 379    int          num, reg;
 380    unsigned     seg2;
 381    DWORD        mask = 0;
 382
 383    assert(_value->cookie == DV_TARGET || _value->cookie == DV_HOST);
 384
 385 #ifdef __i386__
 386    DEBUG_FixAddress( &value.addr, DEBUG_context.SegCs );
 387 #endif
 388
 389    if ( value.type != NULL && value.type == DEBUG_TypeIntConst )
 390    {
 391       /*
 392        * We know that we have the actual offset stored somewhere
 393        * else in 32-bit space.  Grab it, and we
 394        * should be all set.
 395        */
 396       seg2 = value.addr.seg;
 397       value.addr.seg = 0;
 398       value.addr.off = DEBUG_GetExprValue(&value, NULL);
 399       value.addr.seg = seg2;
 400    }
 401
 402    for (num = 1; num < next_bp; num++)
 403    {
 404       if (breakpoints[num].refcount && breakpoints[num].enabled &&
 405           breakpoints[num].type == DBG_WATCH) {
 406          mask |= (1 << breakpoints[num].u.w.reg);
 407       }
 408    }
 409 #ifdef __i386__
 410    for (reg = 0; reg < 4 && (mask & (1 << reg)); reg++);
 411    if (reg == 4)
 412    {
 413       DEBUG_Printf(DBG_CHN_MESG, "All i386 hardware watchpoints have been set. Delete some\n");
 414       return;
 415    }
 416 #endif
 417
 418    if ((num = DEBUG_InitXPoint(DBG_WATCH, &value.addr)) == -1)
 419       return;
 420
 421    breakpoints[num].u.w.len = 4 - 1;
 422    if (_value->type && DEBUG_GetObjectSize(_value->type) < 4)
 423       breakpoints[num].u.w.len = 2 - 1;
 424
 425    if (!DEBUG_GetWatchedValue( num, &breakpoints[num].u.w.oldval))
 426    {
 427       DEBUG_Printf(DBG_CHN_MESG, "Bad address. Watchpoint not set\n");
 428       breakpoints[num].refcount = 0;
 429    }
 430
 431    breakpoints[num].u.w.rw = (is_write) ? TRUE : FALSE;
 432    breakpoints[reg].u.w.reg = reg;
 433
 434    DEBUG_Printf( DBG_CHN_MESG, "Watchpoint %d at ", num );
 435    DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? 32:16, TRUE );
 436    DEBUG_Printf( DBG_CHN_MESG, "\n" );
 437 }
 438
 439 /***********************************************************************
 440  *           DEBUG_DelBreakpoint
 441  *
 442  * Delete a breakpoint.
 443  */
 444 void DEBUG_DelBreakpoint( int num )
 445 {
 446     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 447     {
 448         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 449         return;
 450     }
 451
 452     if (--breakpoints[num].refcount > 0)
 453        return;
 454
 455     if( breakpoints[num].condition != NULL )
 456     {
 457        DEBUG_FreeExpr(breakpoints[num].condition);
 458        breakpoints[num].condition = NULL;
 459     }
 460
 461     breakpoints[num].enabled = FALSE;
 462     breakpoints[num].refcount = 0;
 463     breakpoints[num].skipcount = 0;
 464 }
 465
 466 /***********************************************************************
 467  *           DEBUG_EnableBreakpoint
 468  *
 469  * Enable or disable a break point.
 470  */
 471 void DEBUG_EnableBreakpoint( int num, BOOL enable )
 472 {
 473     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 474     {
 475         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 476         return;
 477     }
 478     breakpoints[num].enabled = (enable) ? TRUE : FALSE;
 479     breakpoints[num].skipcount = 0;
 480 }
 481
 482
 483 /***********************************************************************
 484  *           DEBUG_FindTriggeredWatchpoint
 485  *
 486  * Lookup the watchpoints to see if one has been triggered
 487  * Return >= (watch point index) if one is found and *oldval is set to
 488  *      the value watched before the TRAP
 489  * Return -1 if none found (*oldval is undetermined)
 490  *
 491  * Unfortunately, Linux does *NOT* (A REAL PITA) report with ptrace
 492  * the DR6 register value, so we have to look with our own need the
 493  * cause of the TRAP.
 494  * -EP
 495  */
 496 static int DEBUG_FindTriggeredWatchpoint(LPDWORD oldval)
 497 {
 498    int                          i;
 499    int                          found = -1;
 500    DWORD                        val = 0;
 501
 502    /* Method 1 => get triggered watchpoint from context (doesn't work on Linux
 503     * 2.2.x)
 504     */
 505    for (i = 0; i < next_bp; i++)
 506    {
 507 #ifdef __i386__
 508       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 509           breakpoints[i].type == DBG_WATCH &&
 510           (DEBUG_context.Dr6 & (1 << breakpoints[i].u.w.reg)))
 511       {
 512          DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 513
 514          *oldval = breakpoints[i].u.w.oldval;
 515          if (DEBUG_GetWatchedValue(i, &val)) {
 516             breakpoints[i].u.w.oldval = val;
 517             return i;
 518          }
 519       }
 520 #endif
 521    }
 522
 523    /* Method 1 failed, trying method2 */
 524
 525    /* Method 2 => check if value has changed among registered watchpoints
 526     * this really sucks, but this is how gdb 4.18 works on my linux box
 527     * -EP
 528     */
 529    for (i = 0; i < next_bp; i++)
 530    {
 531 #ifdef __i386__
 532       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 533           breakpoints[i].type == DBG_WATCH &&
 534           DEBUG_GetWatchedValue(i, &val))
 535       {
 536          *oldval = breakpoints[i].u.w.oldval;
 537          if (val != *oldval)
 538          {
 539             DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 540             breakpoints[i].u.w.oldval = val;
 541             found = i;
 542             /* cannot break, because two watch points may have been triggered on
 543              * the same acces
 544              * only one will be reported to the user (FIXME ?)
 545              */
 546          }
 547       }
 548 #endif
 549    }
 550    return found;
 551 }
 552
 553 /***********************************************************************
 554  *           DEBUG_InfoBreakpoints
 555  *
 556  * Display break points information.
 557  */
 558 void DEBUG_InfoBreakpoints(void)
 559 {
 560     int i;
 561
 562     DEBUG_Printf( DBG_CHN_MESG, "Breakpoints:\n" );
 563     for (i = 1; i < next_bp; i++)
 564     {
 565         if (breakpoints[i].refcount && breakpoints[i].type == DBG_BREAK)
 566         {
 567             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 568             DEBUG_PrintAddress( &breakpoints[i].addr,
 569                                 breakpoints[i].is32 ? 32 : 16, TRUE);
 570             DEBUG_Printf( DBG_CHN_MESG, " (%u)\n", breakpoints[i].refcount );
 571             if( breakpoints[i].condition != NULL )
 572             {
 573                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 574                 DEBUG_DisplayExpr(breakpoints[i].condition);
 575                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 576             }
 577         }
 578     }
 579     DEBUG_Printf( DBG_CHN_MESG, "Watchpoints:\n" );
 580     for (i = 1; i < next_bp; i++)
 581     {
 582         if (breakpoints[i].refcount && breakpoints[i].type == DBG_WATCH)
 583         {
 584             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 585             DEBUG_PrintAddress( &breakpoints[i].addr,
 586                                 breakpoints[i].is32 ? 32 : 16, TRUE);
 587             DEBUG_Printf( DBG_CHN_MESG, " on %d byte%s (%c)\n",
 588                      breakpoints[i].u.w.len + 1,
 589                      breakpoints[i].u.w.len > 0 ? "s" : "",
 590                      breakpoints[i].u.w.rw ? 'W' : 'R');
 591             if( breakpoints[i].condition != NULL )
 592             {
 593                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 594                 DEBUG_DisplayExpr(breakpoints[i].condition);
 595                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 596             }
 597         }
 598     }
 599 }
 600
 601 /***********************************************************************
 602  *           DEBUG_ShallBreak
 603  *
 604  * Check whether or not the condition (bp / skipcount) of a break/watch
 605  * point are met.
 606  */
 607 static  BOOL DEBUG_ShallBreak( int bpnum )
 608 {
 609    if ( breakpoints[bpnum].condition != NULL )
 610    {
 611       DBG_VALUE value = DEBUG_EvalExpr(breakpoints[bpnum].condition);
 612
 613       if ( value.type == NULL )
 614       {
 615          /*
 616           * Something wrong - unable to evaluate this expression.
 617           */
 618          DEBUG_Printf(DBG_CHN_MESG, "Unable to evaluate expression ");
 619          DEBUG_DisplayExpr(breakpoints[bpnum].condition);
 620          DEBUG_Printf(DBG_CHN_MESG, "\nTurning off condition\n");
 621          DEBUG_AddBPCondition(bpnum, NULL);
 622       }
 623       else if( !DEBUG_GetExprValue( &value, NULL) )
 624       {
 625          return FALSE;
 626       }
 627    }
 628
 629    if ( breakpoints[bpnum].skipcount > 0 && --breakpoints[bpnum].skipcount > 0 )
 630       return FALSE;
 631
 632    return (breakpoints[bpnum].u.b.func) ? (breakpoints[bpnum].u.b.func)() : TRUE;
 633 }
 634
 635 /***********************************************************************
 636  *           DEBUG_ShouldContinue
 637  *
 638  * Determine if we should continue execution after a SIGTRAP signal when
 639  * executing in the given mode.
 640  */
 641 BOOL DEBUG_ShouldContinue( DWORD code, enum exec_mode mode, int * count )
 642 {
 643     DBG_ADDR    addr;
 644     int         bpnum;
 645     DWORD       oldval;
 646     int         wpnum;
 647     struct symbol_info syminfo;
 648
 649 #ifdef __i386__
 650     /* If not single-stepping, back up over the int3 instruction */
 651     if (code == EXCEPTION_BREAKPOINT)
 652        DEBUG_context.Eip--;
 653 #endif
 654
 655     DEBUG_GetCurrentAddress( &addr );
 656     bpnum = DEBUG_FindBreakpoint( &addr, DBG_BREAK );
 657     breakpoints[0].enabled = FALSE;  /* disable the step-over breakpoint */
 658
 659     if ((bpnum != 0) && (bpnum != -1))
 660     {
 661         if (!DEBUG_ShallBreak(bpnum)) return TRUE;
 662
 663         DEBUG_Printf( DBG_CHN_MESG, "Stopped on breakpoint %d at ", bpnum );
 664         syminfo = DEBUG_PrintAddress( &breakpoints[bpnum].addr,
 665                                       breakpoints[bpnum].is32 ? 32 : 16, TRUE );
 666         DEBUG_Printf( DBG_CHN_MESG, "\n" );
 667
 668         if( syminfo.list.sourcefile != NULL )
 669             DEBUG_List(&syminfo.list, NULL, 0);
 670         return FALSE;
 671     }
 672
 673     wpnum = DEBUG_FindTriggeredWatchpoint(&oldval);
 674     if ((wpnum != 0) && (wpnum != -1))
 675     {
 676        /* If not single-stepping, do not back up over the int3 instruction */
 677        if (code == EXCEPTION_BREAKPOINT)
 678        {
 679 #ifdef __i386__
 680            DEBUG_context.Eip++;
 681            addr.off++;
 682 #endif
 683        }
 684        if (!DEBUG_ShallBreak(wpnum)) return TRUE;
 685
 686        DEBUG_Printf(DBG_CHN_MESG, "Stopped on watchpoint %d at ", wpnum);
 687        syminfo = DEBUG_PrintAddress( &addr, !addr.seg ? 32 :
 688                                      DEBUG_GetSelectorType( addr.seg ), TRUE );
 689
 690        DEBUG_Printf(DBG_CHN_MESG, " values: old=%lu new=%lu\n",
 691                oldval, breakpoints[wpnum].u.w.oldval);
 692        if (syminfo.list.sourcefile != NULL)
 693           DEBUG_List(&syminfo.list, NULL, 0);
 694        return FALSE;
 695     }
 696
 697     /*
 698      * If our mode indicates that we are stepping line numbers,
 699      * get the current function, and figure out if we are exactly
 700      * on a line number or not.
 701      */
 702     if( mode == EXEC_STEP_OVER || mode == EXEC_STEP_INSTR )
 703     {
 704         if( DEBUG_CheckLinenoStatus(&addr) == AT_LINENUMBER )
 705         {
 706             (*count)--;
 707         }
 708     }
 709     else if( mode == EXEC_STEPI_OVER || mode == EXEC_STEPI_INSTR )
 710     {
 711         (*count)--;
 712     }
 713
 714     if( *count > 0 || mode == EXEC_FINISH )
 715     {
 716         /*
 717          * We still need to execute more instructions.
 718          */
 719         return TRUE;
 720     }
 721
 722     /*
 723      * If we are about to stop, then print out the source line if we
 724      * have it.
 725      */
 726     if (mode != EXEC_CONT && mode != EXEC_PASS && mode != EXEC_FINISH)
 727     {
 728         DEBUG_FindNearestSymbol( &addr, TRUE, NULL, 0, &syminfo.list);
 729         if( syminfo.list.sourcefile != NULL )
 730         {
 731             DEBUG_List(&syminfo.list, NULL, 0);
 732         }
 733     }
 734
 735 #ifdef __i386__
 736     /* If there's no breakpoint and we are not single-stepping, then we     */
 737     /* must have encountered an int3 in the Windows program; let's skip it. */
 738     if ((bpnum == -1) && code == EXCEPTION_BREAKPOINT)
 739         DEBUG_context.Eip++;
 740 #endif
 741
 742     /* no breakpoint, continue if in continuous mode */
 743     return (mode == EXEC_CONT || mode == EXEC_PASS || mode == EXEC_FINISH);
 744 }
 745
 746 /***********************************************************************
 747  *           DEBUG_SuspendExecution
 748  *
 749  * Remove all breakpoints before entering the debug loop
 750  */
 751 void    DEBUG_SuspendExecution( void )
 752 {
 753    DEBUG_SetBreakpoints( FALSE );
 754    breakpoints[0] = DEBUG_CurrThread->stepOverBP;
 755 }
 756
 757 /***********************************************************************
 758  *           DEBUG_RestartExecution
 759  *
 760  * Set the breakpoints to the correct state to restart execution
 761  * in the given mode.
 762  */
 763 enum exec_mode DEBUG_RestartExecution( enum exec_mode mode, int count )
 764 {
 765     DBG_ADDR addr;
 766     DBG_ADDR addr2;
 767     int bp;
 768     int delta;
 769     int status;
 770     enum exec_mode ret_mode;
 771     DWORD instr;
 772     unsigned char ch;
 773
 774     DEBUG_GetCurrentAddress( &addr );
 775
 776     /*
 777      * This is the mode we will be running in after we finish.  We would like
 778      * to be able to modify this in certain cases.
 779      */
 780     ret_mode = mode;
 781
 782     bp = DEBUG_FindBreakpoint( &addr, DBG_BREAK );
 783     if ( bp != -1 && bp != 0)
 784       {
 785         /*
 786          * If we have set a new value, then save it in the BP number.
 787          */
 788         if( count != 0 && mode == EXEC_CONT )
 789           {
 790             breakpoints[bp].skipcount = count;
 791           }
 792         mode = EXEC_STEPI_INSTR;  /* If there's a breakpoint, skip it */
 793       }
 794     else
 795       {
 796         if( mode == EXEC_CONT && count > 1 )
 797           {
 798             DEBUG_Printf(DBG_CHN_MESG, "Not stopped at any breakpoint; argument ignored.\n");
 799           }
 800       }
 801
 802     if( mode == EXEC_FINISH && DEBUG_IsFctReturn() )
 803       {
 804         mode = ret_mode = EXEC_STEPI_INSTR;
 805       }
 806
 807     instr = DEBUG_ToLinear( &addr );
 808     DEBUG_READ_MEM((void*)instr, &ch, sizeof(ch));
 809     /*
 810      * See if the function we are stepping into has debug info
 811      * and line numbers.  If not, then we step over it instead.
 812      * FIXME - we need to check for things like thunks or trampolines,
 813      * as the actual function may in fact have debug info.
 814      */
 815     if( ch == 0xe8 )
 816       {
 817         DEBUG_READ_MEM((void*)(instr + 1), &delta, sizeof(delta));
 818         addr2 = addr;
 819         DEBUG_Disasm(&addr2, FALSE);
 820         addr2.off += delta;
 821
 822         status = DEBUG_CheckLinenoStatus(&addr2);
 823         /*
 824          * Anytime we have a trampoline, step over it.
 825          */
 826         if( ((mode == EXEC_STEP_OVER) || (mode == EXEC_STEPI_OVER))
 827             && status == FUNC_IS_TRAMPOLINE )
 828           {
 829 #if 0
 830             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into trampoline at %x (no lines)\n",
 831                     addr2.off);
 832 #endif
 833             mode = EXEC_STEP_OVER_TRAMPOLINE;
 834           }
 835
 836         if( mode == EXEC_STEP_INSTR && status == FUNC_HAS_NO_LINES )
 837           {
 838 #if 0
 839             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into function at %x (no lines)\n",
 840                     addr2.off);
 841 #endif
 842             mode = EXEC_STEP_OVER;
 843           }
 844       }
 845
 846
 847     if( mode == EXEC_STEP_INSTR )
 848       {
 849         if( DEBUG_CheckLinenoStatus(&addr) == FUNC_HAS_NO_LINES )
 850           {
 851             DEBUG_Printf(DBG_CHN_MESG, "Single stepping until exit from function, \n");
 852             DEBUG_Printf(DBG_CHN_MESG, "which has no line number information.\n");
 853
 854             ret_mode = mode = EXEC_FINISH;
 855           }
 856       }
 857
 858     switch(mode)
 859     {
 860     case EXEC_CONT: /* Continuous execution */
 861     case EXEC_PASS: /* Continue, passing exception */
 862 #ifdef __i386__
 863         DEBUG_context.EFlags &= ~STEP_FLAG;
 864 #endif
 865         DEBUG_SetBreakpoints( TRUE );
 866         break;
 867
 868     case EXEC_STEP_OVER_TRAMPOLINE:
 869       /*
 870        * This is the means by which we step over our conversion stubs
 871        * in callfrom*.s and callto*.s.  We dig the appropriate address
 872        * off the stack, and we set the breakpoint there instead of the
 873        * address just after the call.
 874        */
 875 #ifdef __i386__
 876       DEBUG_READ_MEM((void*)(DEBUG_context.Esp +
 877                              2 * sizeof(unsigned int)),
 878                      &addr.off, sizeof(addr.off));
 879       DEBUG_context.EFlags &= ~STEP_FLAG;
 880 #endif
 881       breakpoints[0].addr    = addr;
 882       breakpoints[0].enabled = TRUE;
 883       breakpoints[0].refcount = 1;
 884       breakpoints[0].skipcount = 0;
 885       DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
 886                      sizeof(char));
 887       DEBUG_SetBreakpoints( TRUE );
 888       break;
 889
 890     case EXEC_FINISH:
 891     case EXEC_STEPI_OVER:  /* Stepping over a call */
 892     case EXEC_STEP_OVER:  /* Stepping over a call */
 893         if (DEBUG_IsStepOverInstr())
 894         {
 895 #ifdef __i386__
 896             DEBUG_context.EFlags &= ~STEP_FLAG;
 897 #endif
 898             DEBUG_Disasm(&addr, FALSE);
 899             breakpoints[0].addr    = addr;
 900             breakpoints[0].enabled = TRUE;
 901             breakpoints[0].refcount = 1;
 902             breakpoints[0].skipcount = 0;
 903             DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
 904                            sizeof(char));
 905             DEBUG_SetBreakpoints( TRUE );
 906             break;
 907         }
 908         /* else fall through to single-stepping */
 909
 910     case EXEC_STEP_INSTR: /* Single-stepping an instruction */
 911     case EXEC_STEPI_INSTR: /* Single-stepping an instruction */
 912 #ifdef __i386__
 913         DEBUG_context.EFlags |= STEP_FLAG;
 914 #endif
 915         break;
 916     case EXEC_KILL:
 917         break;
 918     default:
 919         RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 920     }
 921     DEBUG_CurrThread->stepOverBP = breakpoints[0];
 922     return ret_mode;
 923 }
 924
 925 int
 926 DEBUG_AddBPCondition(int num, struct expr * exp)
 927 {
 928     if ((num <= 0) || (num >= next_bp) || !breakpoints[num].refcount)
 929     {
 930         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 931         return FALSE;
 932     }
 933
 934     if( breakpoints[num].condition != NULL )
 935       {
 936         DEBUG_FreeExpr(breakpoints[num].condition);
 937         breakpoints[num].condition = NULL;
 938       }
 939
 940     if( exp != NULL )
 941       {
 942         breakpoints[num].condition = DEBUG_CloneExpr(exp);
 943       }
 944
 945    return TRUE;
 946 }