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
 183             if (!DEBUG_WRITE_MEM( (void*)DEBUG_ToLinear(&breakpoints[i].addr),
 184                                   &ch, sizeof(ch) ))
 185             {
 186                DEBUG_Printf(DBG_CHN_MESG, "Invalid address for breakpoint %d, disabling it\n", i);
 187                breakpoints[i].enabled = FALSE;
 188             }
 189 #endif
 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 #ifdef __i386__
 335     DEBUG_FixAddress( &value.addr, DEBUG_context.SegCs );
 336 #endif
 337
 338     if( value.type != NULL && value.type == DEBUG_TypeIntConst )
 339     {
 340        /*
 341         * We know that we have the actual offset stored somewhere
 342         * else in 32-bit space.  Grab it, and we
 343         * should be all set.
 344         */
 345        seg2 = value.addr.seg;
 346        value.addr.seg = 0;
 347        value.addr.off = DEBUG_GetExprValue(&value, NULL);
 348        value.addr.seg = seg2;
 349     }
 350
 351     if ((num = DEBUG_FindBreakpoint(&value.addr, DBG_BREAK)) >= 1)
 352     {
 353        breakpoints[num].refcount++;
 354        return;
 355     }
 356
 357     if (!DEBUG_READ_MEM_VERBOSE((void*)DEBUG_ToLinear( &value.addr ), &ch, sizeof(ch)))
 358         return;
 359
 360     if ((num = DEBUG_InitXPoint(DBG_BREAK, &value.addr)) == -1)
 361        return;
 362
 363     breakpoints[num].u.b.opcode = ch;
 364     breakpoints[num].u.b.func = func;
 365
 366     DEBUG_Printf( DBG_CHN_MESG, "Breakpoint %d at ", num );
 367     DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? 32 : 16,
 368                         TRUE );
 369     DEBUG_Printf( DBG_CHN_MESG, "\n" );
 370 }
 371
 372
 373  /***********************************************************************
 374  *           DEBUG_AddWatchpoint
 375  *
 376  * Add a watchpoint.
 377  */
 378 void DEBUG_AddWatchpoint( const DBG_VALUE *_value, BOOL is_write )
 379 {
 380    DBG_VALUE    value = *_value;
 381    int          num, reg = -1;
 382    unsigned     seg2;
 383    DWORD        mask = 0;
 384
 385    assert(_value->cookie == DV_TARGET || _value->cookie == DV_HOST);
 386
 387 #ifdef __i386__
 388    DEBUG_FixAddress( &value.addr, DEBUG_context.SegCs );
 389 #endif
 390
 391    if ( value.type != NULL && value.type == DEBUG_TypeIntConst )
 392    {
 393       /*
 394        * We know that we have the actual offset stored somewhere
 395        * else in 32-bit space.  Grab it, and we
 396        * should be all set.
 397        */
 398       seg2 = value.addr.seg;
 399       value.addr.seg = 0;
 400       value.addr.off = DEBUG_GetExprValue(&value, NULL);
 401       value.addr.seg = seg2;
 402    }
 403
 404    for (num = 1; num < next_bp; num++)
 405    {
 406       if (breakpoints[num].refcount && breakpoints[num].enabled &&
 407           breakpoints[num].type == DBG_WATCH) {
 408          mask |= (1 << breakpoints[num].u.w.reg);
 409       }
 410    }
 411 #ifdef __i386__
 412    for (reg = 0; reg < 4 && (mask & (1 << reg)); reg++);
 413    if (reg == 4)
 414    {
 415       DEBUG_Printf(DBG_CHN_MESG, "All i386 hardware watchpoints have been set. Delete some\n");
 416       return;
 417    }
 418 #endif
 419
 420    if ((num = DEBUG_InitXPoint(DBG_WATCH, &value.addr)) == -1)
 421       return;
 422
 423    breakpoints[num].u.w.len = 4 - 1;
 424    if (_value->type && DEBUG_GetObjectSize(_value->type) < 4)
 425       breakpoints[num].u.w.len = 2 - 1;
 426
 427    if (!DEBUG_GetWatchedValue( num, &breakpoints[num].u.w.oldval))
 428    {
 429       DEBUG_Printf(DBG_CHN_MESG, "Bad address. Watchpoint not set\n");
 430       breakpoints[num].refcount = 0;
 431    }
 432
 433    breakpoints[num].u.w.rw = (is_write) ? TRUE : FALSE;
 434    breakpoints[reg].u.w.reg = reg;
 435
 436    DEBUG_Printf( DBG_CHN_MESG, "Watchpoint %d at ", num );
 437    DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? 32:16, TRUE );
 438    DEBUG_Printf( DBG_CHN_MESG, "\n" );
 439 }
 440
 441 /***********************************************************************
 442  *           DEBUG_DelBreakpoint
 443  *
 444  * Delete a breakpoint.
 445  */
 446 void DEBUG_DelBreakpoint( int num )
 447 {
 448     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 449     {
 450         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 451         return;
 452     }
 453
 454     if (--breakpoints[num].refcount > 0)
 455        return;
 456
 457     if( breakpoints[num].condition != NULL )
 458     {
 459        DEBUG_FreeExpr(breakpoints[num].condition);
 460        breakpoints[num].condition = NULL;
 461     }
 462
 463     breakpoints[num].enabled = FALSE;
 464     breakpoints[num].refcount = 0;
 465     breakpoints[num].skipcount = 0;
 466 }
 467
 468 /***********************************************************************
 469  *           DEBUG_EnableBreakpoint
 470  *
 471  * Enable or disable a break point.
 472  */
 473 void DEBUG_EnableBreakpoint( int num, BOOL enable )
 474 {
 475     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 476     {
 477         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 478         return;
 479     }
 480     breakpoints[num].enabled = (enable) ? TRUE : FALSE;
 481     breakpoints[num].skipcount = 0;
 482 }
 483
 484
 485 /***********************************************************************
 486  *           DEBUG_FindTriggeredWatchpoint
 487  *
 488  * Lookup the watchpoints to see if one has been triggered
 489  * Return >= (watch point index) if one is found and *oldval is set to
 490  *      the value watched before the TRAP
 491  * Return -1 if none found (*oldval is undetermined)
 492  *
 493  * Unfortunately, Linux does *NOT* (A REAL PITA) report with ptrace
 494  * the DR6 register value, so we have to look with our own need the
 495  * cause of the TRAP.
 496  * -EP
 497  */
 498 static int DEBUG_FindTriggeredWatchpoint(LPDWORD oldval)
 499 {
 500    int                          i;
 501    int                          found = -1;
 502
 503    /* Method 1 => get triggered watchpoint from context (doesn't work on Linux
 504     * 2.2.x)
 505     */
 506    for (i = 0; i < next_bp; i++)
 507    {
 508 #ifdef __i386__
 509       DWORD val = 0;
 510
 511       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 512           breakpoints[i].type == DBG_WATCH &&
 513           (DEBUG_context.Dr6 & (1 << breakpoints[i].u.w.reg)))
 514       {
 515          DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 516
 517          *oldval = breakpoints[i].u.w.oldval;
 518          if (DEBUG_GetWatchedValue(i, &val)) {
 519             breakpoints[i].u.w.oldval = val;
 520             return i;
 521          }
 522       }
 523 #endif
 524    }
 525
 526    /* Method 1 failed, trying method2 */
 527
 528    /* Method 2 => check if value has changed among registered watchpoints
 529     * this really sucks, but this is how gdb 4.18 works on my linux box
 530     * -EP
 531     */
 532    for (i = 0; i < next_bp; i++)
 533    {
 534 #ifdef __i386__
 535       DWORD val = 0;
 536
 537       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 538           breakpoints[i].type == DBG_WATCH &&
 539           DEBUG_GetWatchedValue(i, &val))
 540       {
 541          *oldval = breakpoints[i].u.w.oldval;
 542          if (val != *oldval)
 543          {
 544             DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 545             breakpoints[i].u.w.oldval = val;
 546             found = i;
 547             /* cannot break, because two watch points may have been triggered on
 548              * the same acces
 549              * only one will be reported to the user (FIXME ?)
 550              */
 551          }
 552       }
 553 #endif
 554    }
 555    return found;
 556 }
 557
 558 /***********************************************************************
 559  *           DEBUG_InfoBreakpoints
 560  *
 561  * Display break points information.
 562  */
 563 void DEBUG_InfoBreakpoints(void)
 564 {
 565     int i;
 566
 567     DEBUG_Printf( DBG_CHN_MESG, "Breakpoints:\n" );
 568     for (i = 1; i < next_bp; i++)
 569     {
 570         if (breakpoints[i].refcount && breakpoints[i].type == DBG_BREAK)
 571         {
 572             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 573             DEBUG_PrintAddress( &breakpoints[i].addr,
 574                                 breakpoints[i].is32 ? 32 : 16, TRUE);
 575             DEBUG_Printf( DBG_CHN_MESG, " (%u)\n", breakpoints[i].refcount );
 576             if( breakpoints[i].condition != NULL )
 577             {
 578                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 579                 DEBUG_DisplayExpr(breakpoints[i].condition);
 580                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 581             }
 582         }
 583     }
 584     DEBUG_Printf( DBG_CHN_MESG, "Watchpoints:\n" );
 585     for (i = 1; i < next_bp; i++)
 586     {
 587         if (breakpoints[i].refcount && breakpoints[i].type == DBG_WATCH)
 588         {
 589             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 590             DEBUG_PrintAddress( &breakpoints[i].addr,
 591                                 breakpoints[i].is32 ? 32 : 16, TRUE);
 592             DEBUG_Printf( DBG_CHN_MESG, " on %d byte%s (%c)\n",
 593                      breakpoints[i].u.w.len + 1,
 594                      breakpoints[i].u.w.len > 0 ? "s" : "",
 595                      breakpoints[i].u.w.rw ? 'W' : 'R');
 596             if( breakpoints[i].condition != NULL )
 597             {
 598                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 599                 DEBUG_DisplayExpr(breakpoints[i].condition);
 600                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 601             }
 602         }
 603     }
 604 }
 605
 606 /***********************************************************************
 607  *           DEBUG_ShallBreak
 608  *
 609  * Check whether or not the condition (bp / skipcount) of a break/watch
 610  * point are met.
 611  */
 612 static  BOOL DEBUG_ShallBreak( int bpnum )
 613 {
 614    if ( breakpoints[bpnum].condition != NULL )
 615    {
 616       DBG_VALUE value = DEBUG_EvalExpr(breakpoints[bpnum].condition);
 617
 618       if ( value.type == NULL )
 619       {
 620          /*
 621           * Something wrong - unable to evaluate this expression.
 622           */
 623          DEBUG_Printf(DBG_CHN_MESG, "Unable to evaluate expression ");
 624          DEBUG_DisplayExpr(breakpoints[bpnum].condition);
 625          DEBUG_Printf(DBG_CHN_MESG, "\nTurning off condition\n");
 626          DEBUG_AddBPCondition(bpnum, NULL);
 627       }
 628       else if( !DEBUG_GetExprValue( &value, NULL) )
 629       {
 630          return FALSE;
 631       }
 632    }
 633
 634    if ( breakpoints[bpnum].skipcount > 0 && --breakpoints[bpnum].skipcount > 0 )
 635       return FALSE;
 636
 637    return (breakpoints[bpnum].u.b.func) ? (breakpoints[bpnum].u.b.func)() : TRUE;
 638 }
 639
 640 /***********************************************************************
 641  *           DEBUG_ShouldContinue
 642  *
 643  * Determine if we should continue execution after a SIGTRAP signal when
 644  * executing in the given mode.
 645  */
 646 BOOL DEBUG_ShouldContinue( DWORD code, enum exec_mode mode, int * count )
 647 {
 648     DBG_ADDR    addr;
 649     int         bpnum;
 650     DWORD       oldval;
 651     int         wpnum;
 652     int         addrlen = 32;
 653     struct symbol_info syminfo;
 654
 655 #ifdef __i386__
 656     /* If not single-stepping, back up over the int3 instruction */
 657     if (code == EXCEPTION_BREAKPOINT)
 658        DEBUG_context.Eip--;
 659 #endif
 660
 661     DEBUG_GetCurrentAddress( &addr );
 662     bpnum = DEBUG_FindBreakpoint( &addr, DBG_BREAK );
 663     breakpoints[0].enabled = FALSE;  /* disable the step-over breakpoint */
 664
 665     if ((bpnum != 0) && (bpnum != -1))
 666     {
 667         if (!DEBUG_ShallBreak(bpnum)) return TRUE;
 668
 669         DEBUG_Printf( DBG_CHN_MESG, "Stopped on breakpoint %d at ", bpnum );
 670         syminfo = DEBUG_PrintAddress( &breakpoints[bpnum].addr,
 671                                       breakpoints[bpnum].is32 ? 32 : 16, TRUE );
 672         DEBUG_Printf( DBG_CHN_MESG, "\n" );
 673
 674         if( syminfo.list.sourcefile != NULL )
 675             DEBUG_List(&syminfo.list, NULL, 0);
 676         return FALSE;
 677     }
 678
 679     wpnum = DEBUG_FindTriggeredWatchpoint(&oldval);
 680     if ((wpnum != 0) && (wpnum != -1))
 681     {
 682        /* If not single-stepping, do not back up over the int3 instruction */
 683        if (code == EXCEPTION_BREAKPOINT)
 684        {
 685 #ifdef __i386__
 686            DEBUG_context.Eip++;
 687            addr.off++;
 688 #endif
 689        }
 690        if (!DEBUG_ShallBreak(wpnum)) return TRUE;
 691
 692 #ifdef __i386__
 693        addrlen = !addr.seg? 32 : DEBUG_GetSelectorType( addr.seg );
 694 #endif
 695        DEBUG_Printf(DBG_CHN_MESG, "Stopped on watchpoint %d at ", wpnum);
 696        syminfo = DEBUG_PrintAddress( &addr, addrlen, TRUE );
 697
 698        DEBUG_Printf(DBG_CHN_MESG, " values: old=%lu new=%lu\n",
 699                oldval, breakpoints[wpnum].u.w.oldval);
 700        if (syminfo.list.sourcefile != NULL)
 701           DEBUG_List(&syminfo.list, NULL, 0);
 702        return FALSE;
 703     }
 704
 705     /*
 706      * If our mode indicates that we are stepping line numbers,
 707      * get the current function, and figure out if we are exactly
 708      * on a line number or not.
 709      */
 710     if( mode == EXEC_STEP_OVER || mode == EXEC_STEP_INSTR )
 711     {
 712         if( DEBUG_CheckLinenoStatus(&addr) == AT_LINENUMBER )
 713         {
 714             (*count)--;
 715         }
 716     }
 717     else if( mode == EXEC_STEPI_OVER || mode == EXEC_STEPI_INSTR )
 718     {
 719         (*count)--;
 720     }
 721
 722     if( *count > 0 || mode == EXEC_FINISH )
 723     {
 724         /*
 725          * We still need to execute more instructions.
 726          */
 727         return TRUE;
 728     }
 729
 730     /*
 731      * If we are about to stop, then print out the source line if we
 732      * have it.
 733      */
 734     if (mode != EXEC_CONT && mode != EXEC_PASS && mode != EXEC_FINISH)
 735     {
 736         DEBUG_FindNearestSymbol( &addr, TRUE, NULL, 0, &syminfo.list);
 737         if( syminfo.list.sourcefile != NULL )
 738         {
 739             DEBUG_List(&syminfo.list, NULL, 0);
 740         }
 741     }
 742
 743 #ifdef __i386__
 744     /* If there's no breakpoint and we are not single-stepping, then we     */
 745     /* must have encountered an int3 in the Windows program; let's skip it. */
 746     if ((bpnum == -1) && code == EXCEPTION_BREAKPOINT)
 747         DEBUG_context.Eip++;
 748 #endif
 749
 750     /* no breakpoint, continue if in continuous mode */
 751     return (mode == EXEC_CONT || mode == EXEC_PASS || mode == EXEC_FINISH);
 752 }
 753
 754 /***********************************************************************
 755  *           DEBUG_SuspendExecution
 756  *
 757  * Remove all breakpoints before entering the debug loop
 758  */
 759 void    DEBUG_SuspendExecution( void )
 760 {
 761    DEBUG_SetBreakpoints( FALSE );
 762    breakpoints[0] = DEBUG_CurrThread->stepOverBP;
 763 }
 764
 765 /***********************************************************************
 766  *           DEBUG_RestartExecution
 767  *
 768  * Set the breakpoints to the correct state to restart execution
 769  * in the given mode.
 770  */
 771 enum exec_mode DEBUG_RestartExecution( enum exec_mode mode, int count )
 772 {
 773     DBG_ADDR addr;
 774     DBG_ADDR addr2;
 775     int bp;
 776     int delta;
 777     int status;
 778     enum exec_mode ret_mode;
 779     DWORD instr;
 780     unsigned char ch;
 781
 782     DEBUG_GetCurrentAddress( &addr );
 783
 784     /*
 785      * This is the mode we will be running in after we finish.  We would like
 786      * to be able to modify this in certain cases.
 787      */
 788     ret_mode = mode;
 789
 790     bp = DEBUG_FindBreakpoint( &addr, DBG_BREAK );
 791     if ( bp != -1 && bp != 0)
 792       {
 793         /*
 794          * If we have set a new value, then save it in the BP number.
 795          */
 796         if( count != 0 && mode == EXEC_CONT )
 797           {
 798             breakpoints[bp].skipcount = count;
 799           }
 800         mode = EXEC_STEPI_INSTR;  /* If there's a breakpoint, skip it */
 801       }
 802     else
 803       {
 804         if( mode == EXEC_CONT && count > 1 )
 805           {
 806             DEBUG_Printf(DBG_CHN_MESG, "Not stopped at any breakpoint; argument ignored.\n");
 807           }
 808       }
 809
 810     if( mode == EXEC_FINISH && DEBUG_IsFctReturn() )
 811       {
 812         mode = ret_mode = EXEC_STEPI_INSTR;
 813       }
 814
 815     instr = DEBUG_ToLinear( &addr );
 816     DEBUG_READ_MEM((void*)instr, &ch, sizeof(ch));
 817     /*
 818      * See if the function we are stepping into has debug info
 819      * and line numbers.  If not, then we step over it instead.
 820      * FIXME - we need to check for things like thunks or trampolines,
 821      * as the actual function may in fact have debug info.
 822      */
 823     if( ch == 0xe8 )
 824       {
 825         DEBUG_READ_MEM((void*)(instr + 1), &delta, sizeof(delta));
 826         addr2 = addr;
 827         DEBUG_Disasm(&addr2, FALSE);
 828         addr2.off += delta;
 829
 830         status = DEBUG_CheckLinenoStatus(&addr2);
 831         /*
 832          * Anytime we have a trampoline, step over it.
 833          */
 834         if( ((mode == EXEC_STEP_OVER) || (mode == EXEC_STEPI_OVER))
 835             && status == FUNC_IS_TRAMPOLINE )
 836           {
 837 #if 0
 838             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into trampoline at %x (no lines)\n",
 839                     addr2.off);
 840 #endif
 841             mode = EXEC_STEP_OVER_TRAMPOLINE;
 842           }
 843
 844         if( mode == EXEC_STEP_INSTR && status == FUNC_HAS_NO_LINES )
 845           {
 846 #if 0
 847             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into function at %x (no lines)\n",
 848                     addr2.off);
 849 #endif
 850             mode = EXEC_STEP_OVER;
 851           }
 852       }
 853
 854
 855     if( mode == EXEC_STEP_INSTR )
 856       {
 857         if( DEBUG_CheckLinenoStatus(&addr) == FUNC_HAS_NO_LINES )
 858           {
 859             DEBUG_Printf(DBG_CHN_MESG, "Single stepping until exit from function, \n");
 860             DEBUG_Printf(DBG_CHN_MESG, "which has no line number information.\n");
 861
 862             ret_mode = mode = EXEC_FINISH;
 863           }
 864       }
 865
 866     switch(mode)
 867     {
 868     case EXEC_CONT: /* Continuous execution */
 869     case EXEC_PASS: /* Continue, passing exception */
 870 #ifdef __i386__
 871         DEBUG_context.EFlags &= ~STEP_FLAG;
 872 #endif
 873         DEBUG_SetBreakpoints( TRUE );
 874         break;
 875
 876     case EXEC_STEP_OVER_TRAMPOLINE:
 877       /*
 878        * This is the means by which we step over our conversion stubs
 879        * in callfrom*.s and callto*.s.  We dig the appropriate address
 880        * off the stack, and we set the breakpoint there instead of the
 881        * address just after the call.
 882        */
 883 #ifdef __i386__
 884       DEBUG_READ_MEM((void*)(DEBUG_context.Esp +
 885                              2 * sizeof(unsigned int)),
 886                      &addr.off, sizeof(addr.off));
 887       DEBUG_context.EFlags &= ~STEP_FLAG;
 888 #endif
 889       breakpoints[0].addr    = addr;
 890       breakpoints[0].enabled = TRUE;
 891       breakpoints[0].refcount = 1;
 892       breakpoints[0].skipcount = 0;
 893       DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
 894                      sizeof(char));
 895       DEBUG_SetBreakpoints( TRUE );
 896       break;
 897
 898     case EXEC_FINISH:
 899     case EXEC_STEPI_OVER:  /* Stepping over a call */
 900     case EXEC_STEP_OVER:  /* Stepping over a call */
 901         if (DEBUG_IsStepOverInstr())
 902         {
 903 #ifdef __i386__
 904             DEBUG_context.EFlags &= ~STEP_FLAG;
 905 #endif
 906             DEBUG_Disasm(&addr, FALSE);
 907             breakpoints[0].addr    = addr;
 908             breakpoints[0].enabled = TRUE;
 909             breakpoints[0].refcount = 1;
 910             breakpoints[0].skipcount = 0;
 911             DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
 912                            sizeof(char));
 913             DEBUG_SetBreakpoints( TRUE );
 914             break;
 915         }
 916         /* else fall through to single-stepping */
 917
 918     case EXEC_STEP_INSTR: /* Single-stepping an instruction */
 919     case EXEC_STEPI_INSTR: /* Single-stepping an instruction */
 920 #ifdef __i386__
 921         DEBUG_context.EFlags |= STEP_FLAG;
 922 #endif
 923         break;
 924     case EXEC_KILL:
 925         break;
 926     default:
 927         RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 928     }
 929     DEBUG_CurrThread->stepOverBP = breakpoints[0];
 930     return ret_mode;
 931 }
 932
 933 int
 934 DEBUG_AddBPCondition(int num, struct expr * exp)
 935 {
 936     if ((num <= 0) || (num >= next_bp) || !breakpoints[num].refcount)
 937     {
 938         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 939         return FALSE;
 940     }
 941
 942     if( breakpoints[num].condition != NULL )
 943       {
 944         DEBUG_FreeExpr(breakpoints[num].condition);
 945         breakpoints[num].condition = NULL;
 946       }
 947
 948     if( exp != NULL )
 949       {
 950         breakpoints[num].condition = DEBUG_CloneExpr(exp);
 951       }
 952
 953    return TRUE;
 954 }