programs/winedbg/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  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include "config.h"
  24 #include "debugger.h"
  25
  26 #ifdef __i386__
  27 #define DR7_CONTROL_SHIFT       16
  28 #define DR7_CONTROL_SIZE        4
  29
  30 #define DR7_RW_EXECUTE          (0x0)
  31 #define DR7_RW_WRITE            (0x1)
  32 #define DR7_RW_READ             (0x3)
  33
  34 #define DR7_LEN_1               (0x0)
  35 #define DR7_LEN_2               (0x4)
  36 #define DR7_LEN_4               (0xC)
  37
  38 #define DR7_LOCAL_ENABLE_SHIFT  0
  39 #define DR7_GLOBAL_ENABLE_SHIFT 1
  40 #define DR7_ENABLE_SIZE         2
  41
  42 #define DR7_LOCAL_ENABLE_MASK   (0x55)
  43 #define DR7_GLOBAL_ENABLE_MASK  (0xAA)
  44
  45 #define DR7_CONTROL_RESERVED    (0xFC00)
  46 #define DR7_LOCAL_SLOWDOWN      (0x100)
  47 #define DR7_GLOBAL_SLOWDOWN     (0x200)
  48
  49 #define DR7_ENABLE_MASK(dr)     (1<<(DR7_LOCAL_ENABLE_SHIFT+DR7_ENABLE_SIZE*(dr)))
  50 #define IS_DR7_SET(ctrl,dr)     ((ctrl)&DR7_ENABLE_MASK(dr))
  51 #define INT3          0xcc   /* int 3 opcode */
  52 #endif
  53
  54 #define MAX_BREAKPOINTS 100
  55
  56 static DBG_BREAKPOINT breakpoints[MAX_BREAKPOINTS];
  57
  58 static int next_bp = 1;  /* breakpoint 0 is reserved for step-over */
  59
  60 /***********************************************************************
  61  *           DEBUG_IsStepOverInstr
  62  *
  63  * Determine if the instruction at CS:EIP is an instruction that
  64  * we need to step over (like a call or a repetitive string move).
  65  */
  66 static BOOL DEBUG_IsStepOverInstr(void)
  67 {
  68 #ifdef __i386__
  69     BYTE*       instr;
  70     BYTE        ch;
  71     DBG_ADDR    addr;
  72
  73     addr.seg = DEBUG_context.SegCs;
  74     addr.off = DEBUG_context.Eip;
  75     /* FIXME: old code was using V86BASE(DEBUG_context)
  76      * instead of passing through DOSMEM_MemoryBase
  77      */
  78     instr = (BYTE*)DEBUG_ToLinear(&addr);
  79
  80     for (;;)
  81     {
  82         if (!DEBUG_READ_MEM(instr, &ch, sizeof(ch)))
  83             return FALSE;
  84
  85         switch (ch)
  86         {
  87           /* Skip all prefixes */
  88
  89         case 0x2e:  /* cs: */
  90         case 0x36:  /* ss: */
  91         case 0x3e:  /* ds: */
  92         case 0x26:  /* es: */
  93         case 0x64:  /* fs: */
  94         case 0x65:  /* gs: */
  95         case 0x66:  /* opcode size prefix */
  96         case 0x67:  /* addr size prefix */
  97         case 0xf0:  /* lock */
  98         case 0xf2:  /* repne */
  99         case 0xf3:  /* repe */
 100             instr++;
 101             continue;
 102
 103           /* Handle call instructions */
 104
 105         case 0xcd:  /* int <intno> */
 106         case 0xe8:  /* call <offset> */
 107         case 0x9a:  /* lcall <seg>:<off> */
 108             return TRUE;
 109
 110         case 0xff:  /* call <regmodrm> */
 111             if (!DEBUG_READ_MEM(instr + 1, &ch, sizeof(ch)))
 112                 return FALSE;
 113             return (((ch & 0x38) == 0x10) || ((ch & 0x38) == 0x18));
 114
 115           /* Handle string instructions */
 116
 117         case 0x6c:  /* insb */
 118         case 0x6d:  /* insw */
 119         case 0x6e:  /* outsb */
 120         case 0x6f:  /* outsw */
 121         case 0xa4:  /* movsb */
 122         case 0xa5:  /* movsw */
 123         case 0xa6:  /* cmpsb */
 124         case 0xa7:  /* cmpsw */
 125         case 0xaa:  /* stosb */
 126         case 0xab:  /* stosw */
 127         case 0xac:  /* lodsb */
 128         case 0xad:  /* lodsw */
 129         case 0xae:  /* scasb */
 130         case 0xaf:  /* scasw */
 131             return TRUE;
 132
 133         default:
 134             return FALSE;
 135         }
 136     }
 137 #else
 138     return FALSE;
 139 #endif
 140 }
 141
 142
 143 /***********************************************************************
 144  *           DEBUG_IsFctReturn
 145  *
 146  * Determine if the instruction at CS:EIP is an instruction that
 147  * is a function return.
 148  */
 149 BOOL DEBUG_IsFctReturn(void)
 150 {
 151 #ifdef __i386__
 152     BYTE*       instr;
 153     BYTE        ch;
 154     DBG_ADDR    addr;
 155
 156     addr.seg = DEBUG_context.SegCs;
 157     addr.off = DEBUG_context.Eip;
 158     /* FIXME: old code was using V86BASE(DEBUG_context)
 159      * instead of passing through DOSMEM_MemoryBase
 160      */
 161     instr = (BYTE*)DEBUG_ToLinear(&addr);
 162
 163     if (!DEBUG_READ_MEM(instr, &ch, sizeof(ch)))
 164         return FALSE;
 165
 166     return (ch == 0xc2) || (ch == 0xc3);
 167 #else
 168     return FALSE;
 169 #endif
 170 }
 171
 172
 173 /***********************************************************************
 174  *           DEBUG_SetBreakpoints
 175  *
 176  * Set or remove all the breakpoints.
 177  */
 178 void DEBUG_SetBreakpoints( BOOL set )
 179 {
 180    int          i;
 181
 182 #ifdef __i386__
 183    DEBUG_context.Dr7 &= ~DR7_LOCAL_ENABLE_MASK;
 184 #endif
 185
 186    for (i = 0; i < next_bp; i++)
 187    {
 188       if (!(breakpoints[i].refcount && breakpoints[i].enabled))
 189          continue;
 190
 191       switch (breakpoints[i].type) {
 192       case DBG_BREAK:
 193          {
 194 #ifdef __i386__
 195             char ch = set ? INT3 : breakpoints[i].u.b.opcode;
 196
 197             if (!DEBUG_WRITE_MEM( (void*)DEBUG_ToLinear(&breakpoints[i].addr),
 198                                   &ch, sizeof(ch) ))
 199             {
 200                DEBUG_Printf(DBG_CHN_MESG, "Invalid address for breakpoint %d, disabling it\n", i);
 201                breakpoints[i].enabled = FALSE;
 202             }
 203 #endif
 204          }
 205          break;
 206       case DBG_WATCH:
 207          if (set)
 208          {
 209 #ifdef __i386__
 210             DWORD       bits;
 211             int         reg = breakpoints[i].u.w.reg;
 212             LPDWORD     lpdr = NULL;
 213
 214             switch (reg)
 215             {
 216                case 0: lpdr = &DEBUG_context.Dr0; break;
 217                case 1: lpdr = &DEBUG_context.Dr1; break;
 218                case 2: lpdr = &DEBUG_context.Dr2; break;
 219                case 3: lpdr = &DEBUG_context.Dr3; break;
 220                default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 221             }
 222
 223             *lpdr = DEBUG_ToLinear(&breakpoints[i].addr);
 224             bits = (breakpoints[i].u.w.rw) ? DR7_RW_WRITE : DR7_RW_READ;
 225             switch (breakpoints[i].u.w.len + 1)
 226             {
 227                case 4: bits |= DR7_LEN_4;       break;
 228                case 2: bits |= DR7_LEN_2;       break;
 229                case 1: bits |= DR7_LEN_1;       break;
 230                default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 231             }
 232
 233             DEBUG_context.Dr7 &= ~(0x0F << (DR7_CONTROL_SHIFT + DR7_CONTROL_SIZE * reg));
 234             DEBUG_context.Dr7 |= bits << (DR7_CONTROL_SHIFT + DR7_CONTROL_SIZE * reg);
 235             DEBUG_context.Dr7 |= DR7_ENABLE_MASK(reg) | DR7_LOCAL_SLOWDOWN;
 236 #endif
 237          }
 238          break;
 239       }
 240    }
 241 }
 242
 243 /***********************************************************************
 244  *           DEBUG_FindBreakpoint
 245  *
 246  * Find the breakpoint for a given address. Return the breakpoint
 247  * number or -1 if none.
 248  * If type is DBG_BREAKPOINT, addr is a complete addr
 249  * If type is DBG_WATCHPOINT, only addr.off is meaningful and contains
 250  * linear address
 251  */
 252 static int DEBUG_FindBreakpoint( const DBG_ADDR *addr, int type )
 253 {
 254    int i;
 255
 256    for (i = 0; i < next_bp; i++)
 257    {
 258       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 259           breakpoints[i].type == type )
 260       {
 261          if ((type == DBG_BREAK &&
 262               breakpoints[i].addr.seg == addr->seg &&
 263               breakpoints[i].addr.off == addr->off) ||
 264              (type == DBG_WATCH &&
 265               DEBUG_ToLinear(&breakpoints[i].addr) == addr->off))
 266             return i;
 267       }
 268    }
 269    return -1;
 270 }
 271
 272 /***********************************************************************
 273  *           DEBUG_InitXPoint
 274  *
 275  * Find an empty slot in BP table to add a new break/watch point
 276  */
 277 static  int     DEBUG_InitXPoint(int type, const DBG_ADDR* addr)
 278 {
 279    int  num;
 280
 281    for (num = (next_bp < MAX_BREAKPOINTS) ? next_bp++ : 1;
 282         num < MAX_BREAKPOINTS; num++)
 283    {
 284       if (breakpoints[num].refcount == 0)
 285       {
 286           breakpoints[num].refcount = 1;
 287           breakpoints[num].enabled = TRUE;
 288           breakpoints[num].type    = type;
 289           breakpoints[num].skipcount = 0;
 290           breakpoints[num].addr = *addr;
 291           switch (DEBUG_GetSelectorType( addr->seg ))
 292           {
 293           case MODE_32:
 294               breakpoints[num].is32 = 1;
 295               break;
 296           case MODE_VM86:
 297           case MODE_16:
 298               breakpoints[num].is32 = 0;
 299               break;
 300           default:
 301               RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 302           }
 303           return num;
 304       }
 305    }
 306
 307    DEBUG_Printf( DBG_CHN_MESG, "Too many breakpoints. Please delete some.\n" );
 308    return -1;
 309 }
 310
 311 /***********************************************************************
 312  *           DEBUG_GetWatchedValue
 313  *
 314  * Returns the value watched by watch point 'num'.
 315  */
 316 static  BOOL    DEBUG_GetWatchedValue( int num, LPDWORD val )
 317 {
 318    BYTE         buf[4];
 319
 320    if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&breakpoints[num].addr),
 321                        buf, breakpoints[num].u.w.len + 1))
 322       return FALSE;
 323
 324    switch (breakpoints[num].u.w.len + 1)
 325    {
 326       case 4:   *val = *(DWORD*)buf;    break;
 327       case 2:   *val = *(WORD*)buf;     break;
 328       case 1:   *val = *(BYTE*)buf;     break;
 329       default: RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 330    }
 331    return TRUE;
 332 }
 333
 334 /***********************************************************************
 335  *           DEBUG_AddBreakpoint
 336  *
 337  * Add a breakpoint.
 338  */
 339 BOOL DEBUG_AddBreakpoint( const DBG_VALUE *value, BOOL (*func)(void), BOOL verbose )
 340 {
 341     int num;
 342     BYTE ch;
 343
 344     if ((num = DEBUG_FindBreakpoint(&value->addr, DBG_BREAK)) >= 1)
 345     {
 346         breakpoints[num].refcount++;
 347         return TRUE;
 348     }
 349
 350     if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear( &value->addr ), &ch, sizeof(ch)))
 351     {
 352         if (verbose)
 353             DEBUG_Printf( DBG_CHN_MESG, "Invalid address, can't set breakpoint\n");
 354         return FALSE;
 355     }
 356
 357     if ((num = DEBUG_InitXPoint(DBG_BREAK, &value->addr)) == -1)
 358         return FALSE;
 359
 360     breakpoints[num].u.b.opcode = ch;
 361     breakpoints[num].u.b.func = func;
 362
 363     DEBUG_Printf( DBG_CHN_MESG, "Breakpoint %d at ", num );
 364     DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? MODE_32 : MODE_16,
 365                         TRUE );
 366     DEBUG_Printf( DBG_CHN_MESG, "\n" );
 367
 368     return FALSE;
 369 }
 370
 371 /***********************************************************************
 372  *           DEBUG_AddBreakpointFromValue
 373  *
 374  * Add a breakpoint.
 375  */
 376 BOOL DEBUG_AddBreakpointFromValue( const DBG_VALUE *_value )
 377 {
 378     DBG_VALUE value = *_value;
 379
 380     if (value.type != NULL && value.type == DEBUG_GetBasicType(DT_BASIC_CONST_INT) && value.cookie == DV_HOST)
 381     {
 382         /*
 383          * We know that we have the actual offset stored somewhere
 384          * else in 32-bit space.  Grab it, and we
 385          * should be all set.
 386          */
 387         unsigned int seg2 = value.addr.seg;
 388         value.addr.seg = 0;
 389         value.addr.off = DEBUG_GetExprValue(&value, NULL);
 390         value.addr.seg = seg2;
 391         value.cookie = DV_TARGET;
 392     }
 393
 394     if (!DEBUG_AddBreakpoint( &value, NULL, TRUE ))
 395     {
 396         if (!DBG_IVAR(CanDeferOnBPByAddr))
 397         {
 398             DEBUG_Printf( DBG_CHN_MESG, "Invalid address, can't set breakpoint\n"
 399                           "You can turn on deferring breakpoints by address by setting $CanDeferOnBPByAddr to 1\n");
 400             return FALSE;
 401         }
 402         DEBUG_Printf(DBG_CHN_MESG, "Unable to add breakpoint, will check again any time a new DLL is loaded\n");
 403         DEBUG_CurrProcess->delayed_bp = DBG_realloc(DEBUG_CurrProcess->delayed_bp,
 404                                                     sizeof(DBG_DELAYED_BP) * ++DEBUG_CurrProcess->num_delayed_bp);
 405
 406         DEBUG_CurrProcess->delayed_bp[DEBUG_CurrProcess->num_delayed_bp - 1].is_symbol = FALSE;
 407         DEBUG_CurrProcess->delayed_bp[DEBUG_CurrProcess->num_delayed_bp - 1].u.value = value;
 408         return TRUE;
 409     }
 410
 411     return TRUE;
 412 }
 413
 414 /***********************************************************************
 415  *           DEBUG_AddBreakpointFromId
 416  *
 417  * Add a breakpoint from a function name (and eventually a line #)
 418  */
 419 void    DEBUG_AddBreakpointFromId(const char *name, int lineno)
 420 {
 421     DBG_VALUE   value;
 422     int         i;
 423
 424     switch (DEBUG_GetSymbolValue(name, lineno, &value, TRUE))
 425     {
 426     case gsv_found:
 427         DEBUG_AddBreakpoint(&value, NULL, TRUE);
 428         return;
 429     case gsv_unknown:
 430         break;
 431     case gsv_aborted: /* user aborted symbol lookup */
 432         return;
 433     }
 434
 435     DEBUG_Printf(DBG_CHN_MESG, "Unable to add breakpoint, will check again when a new DLL is loaded\n");
 436     for (i = 0; i < DEBUG_CurrProcess->num_delayed_bp; i++)
 437     {
 438         if (DEBUG_CurrProcess->delayed_bp[i].is_symbol &&
 439             !strcmp(name, DEBUG_CurrProcess->delayed_bp[i].u.symbol.name) &&
 440             lineno == DEBUG_CurrProcess->delayed_bp[i].u.symbol.lineno)
 441             return;
 442     }
 443     DEBUG_CurrProcess->delayed_bp = DBG_realloc(DEBUG_CurrProcess->delayed_bp,
 444                                                 sizeof(DBG_DELAYED_BP) * ++DEBUG_CurrProcess->num_delayed_bp);
 445
 446     DEBUG_CurrProcess->delayed_bp[DEBUG_CurrProcess->num_delayed_bp - 1].is_symbol = TRUE;
 447     DEBUG_CurrProcess->delayed_bp[DEBUG_CurrProcess->num_delayed_bp - 1].u.symbol.name = strcpy(DBG_alloc(strlen(name) + 1), name);
 448     DEBUG_CurrProcess->delayed_bp[DEBUG_CurrProcess->num_delayed_bp - 1].u.symbol.lineno = lineno;
 449 }
 450
 451 /***********************************************************************
 452  *           DEBUG_AddBreakpointFromLineno
 453  *
 454  * Add a breakpoint from a line number in current file
 455  */
 456 void    DEBUG_AddBreakpointFromLineno(int lineno)
 457 {
 458     DBG_VALUE                   value;
 459
 460     DEBUG_GetCurrentAddress(&value.addr);
 461
 462     if (lineno != -1)
 463     {
 464         struct name_hash*       nh;
 465
 466         DEBUG_FindNearestSymbol(&value.addr, TRUE, &nh, 0, NULL);
 467         if (nh == NULL)
 468         {
 469             DEBUG_Printf(DBG_CHN_MESG, "Unable to add breakpoint\n");
 470             return;
 471         }
 472         DEBUG_GetLineNumberAddr(nh, lineno, &value.addr, TRUE);
 473     }
 474
 475     value.type = NULL;
 476     value.cookie = DV_TARGET;
 477     DEBUG_AddBreakpoint( &value,NULL, TRUE );
 478 }
 479
 480 /***********************************************************************
 481  *           DEBUG_CheckDelayedBP
 482  *
 483  * Check is a registered delayed BP is now available.
 484  */
 485 void            DEBUG_CheckDelayedBP(void)
 486 {
 487     DBG_VALUE           value;
 488     int                 i;
 489     DBG_DELAYED_BP*     dbp = DEBUG_CurrProcess->delayed_bp;
 490
 491     for (i = 0; i < DEBUG_CurrProcess->num_delayed_bp; i++)
 492     {
 493         if (dbp[i].is_symbol)
 494         {
 495             if (DEBUG_GetSymbolValue(dbp[i].u.symbol.name, dbp[i].u.symbol.lineno, &value, TRUE) != gsv_found)
 496                 continue;
 497         }
 498         else
 499             value = dbp[i].u.value;
 500         DEBUG_Printf(DBG_CHN_MESG, "trying to add delayed %s-bp\n", dbp[i].is_symbol ? "S" : "A");
 501         if (!dbp[i].is_symbol)
 502             DEBUG_Printf(DBG_CHN_MESG, "\t%04x %04lx:%08lx\n",
 503                          dbp[i].u.value.cookie,
 504                          dbp[i].u.value.addr.seg,
 505                          dbp[i].u.value.addr.off);
 506         else
 507             DEBUG_Printf(DBG_CHN_MESG, "\t'%s' @ %d\n",
 508                          dbp[i].u.symbol.name, dbp[i].u.symbol.lineno);
 509
 510         if (DEBUG_AddBreakpoint(&value, NULL, FALSE))
 511             memmove(&dbp[i], &dbp[i+1], (--DEBUG_CurrProcess->num_delayed_bp - i) * sizeof(*dbp));
 512     }
 513 }
 514
 515 /***********************************************************************
 516  *           DEBUG_AddWatchpoint
 517  *
 518  * Add a watchpoint.
 519  */
 520 void DEBUG_AddWatchpoint( const DBG_VALUE *_value, BOOL is_write )
 521 {
 522    DBG_VALUE    value = *_value;
 523    int          num, reg = -1;
 524    unsigned     seg2;
 525    DWORD        mask = 0;
 526
 527    assert(_value->cookie == DV_TARGET || _value->cookie == DV_HOST);
 528
 529 #ifdef __i386__
 530    DEBUG_FixAddress( &value.addr, DEBUG_context.SegCs );
 531 #endif
 532
 533    if ( value.type != NULL && value.type == DEBUG_GetBasicType(DT_BASIC_CONST_INT) )
 534    {
 535       /*
 536        * We know that we have the actual offset stored somewhere
 537        * else in 32-bit space.  Grab it, and we
 538        * should be all set.
 539        */
 540       seg2 = value.addr.seg;
 541       value.addr.seg = 0;
 542       value.addr.off = DEBUG_GetExprValue(&value, NULL);
 543       value.addr.seg = seg2;
 544    }
 545
 546    for (num = 1; num < next_bp; num++)
 547    {
 548       if (breakpoints[num].refcount && breakpoints[num].enabled &&
 549           breakpoints[num].type == DBG_WATCH) {
 550          mask |= (1 << breakpoints[num].u.w.reg);
 551       }
 552    }
 553 #ifdef __i386__
 554    for (reg = 0; reg < 4 && (mask & (1 << reg)); reg++);
 555    if (reg == 4)
 556    {
 557       DEBUG_Printf(DBG_CHN_MESG, "All i386 hardware watchpoints have been set. Delete some\n");
 558       return;
 559    }
 560 #endif
 561
 562    if ((num = DEBUG_InitXPoint(DBG_WATCH, &value.addr)) == -1)
 563       return;
 564
 565    breakpoints[num].u.w.len = 4 - 1;
 566    if (_value->type && DEBUG_GetObjectSize(_value->type) < 4)
 567       breakpoints[num].u.w.len = 2 - 1;
 568
 569    if (!DEBUG_GetWatchedValue( num, &breakpoints[num].u.w.oldval))
 570    {
 571       DEBUG_Printf(DBG_CHN_MESG, "Bad address. Watchpoint not set\n");
 572       breakpoints[num].refcount = 0;
 573    }
 574    else
 575    {
 576       breakpoints[num].u.w.rw = (is_write) ? TRUE : FALSE;
 577       breakpoints[reg].u.w.reg = reg;
 578
 579       DEBUG_Printf( DBG_CHN_MESG, "Watchpoint %d at ", num );
 580       DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].is32 ? MODE_32 : MODE_16, TRUE );
 581       DEBUG_Printf( DBG_CHN_MESG, "\n" );
 582    }
 583 }
 584
 585 /***********************************************************************
 586  *           DEBUG_AddWathpointFromId
 587  *
 588  * Add a watchpoint from a symbol name (and eventually a line #)
 589  */
 590 void    DEBUG_AddWatchpointFromId(const char *name)
 591 {
 592    DBG_VALUE value;
 593
 594    switch (DEBUG_GetSymbolValue(name, -1, &value, TRUE))
 595    {
 596    case gsv_found:
 597       DEBUG_AddWatchpoint( &value, 1 );
 598       break;
 599    case gsv_unknown:
 600       DEBUG_Printf(DBG_CHN_MESG, "Unable to add watchpoint\n");
 601       break;
 602    case gsv_aborted: /* user aborted symbol lookup */
 603        break;
 604    }
 605 }
 606
 607 /***********************************************************************
 608  *           DEBUG_DelBreakpoint
 609  *
 610  * Delete a breakpoint.
 611  */
 612 void DEBUG_DelBreakpoint( int num )
 613 {
 614     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 615     {
 616         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 617         return;
 618     }
 619
 620     if (--breakpoints[num].refcount > 0)
 621        return;
 622
 623     if( breakpoints[num].condition != NULL )
 624     {
 625        DEBUG_FreeExpr(breakpoints[num].condition);
 626        breakpoints[num].condition = NULL;
 627     }
 628
 629     breakpoints[num].enabled = FALSE;
 630     breakpoints[num].refcount = 0;
 631     breakpoints[num].skipcount = 0;
 632 }
 633
 634 /***********************************************************************
 635  *           DEBUG_EnableBreakpoint
 636  *
 637  * Enable or disable a break point.
 638  */
 639 void DEBUG_EnableBreakpoint( int num, BOOL enable )
 640 {
 641     if ((num <= 0) || (num >= next_bp) || breakpoints[num].refcount == 0)
 642     {
 643         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
 644         return;
 645     }
 646     breakpoints[num].enabled = (enable) ? TRUE : FALSE;
 647     breakpoints[num].skipcount = 0;
 648 }
 649
 650
 651 /***********************************************************************
 652  *           DEBUG_FindTriggeredWatchpoint
 653  *
 654  * Lookup the watchpoints to see if one has been triggered
 655  * Return >= (watch point index) if one is found and *oldval is set to
 656  *      the value watched before the TRAP
 657  * Return -1 if none found (*oldval is undetermined)
 658  *
 659  * Unfortunately, Linux does *NOT* (A REAL PITA) report with ptrace
 660  * the DR6 register value, so we have to look with our own need the
 661  * cause of the TRAP.
 662  * -EP
 663  */
 664 static int DEBUG_FindTriggeredWatchpoint(LPDWORD oldval)
 665 {
 666    int                          found = -1;
 667 #ifdef __i386__
 668    int                          i;
 669
 670    /* Method 1 => get triggered watchpoint from context (doesn't work on Linux
 671     * 2.2.x). This should be fixed in >= 2.2.16
 672     */
 673    for (i = 0; i < next_bp; i++)
 674    {
 675       DWORD val = 0;
 676
 677       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 678           breakpoints[i].type == DBG_WATCH &&
 679           (DEBUG_context.Dr6 & (1 << breakpoints[i].u.w.reg)))
 680       {
 681          DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 682
 683          *oldval = breakpoints[i].u.w.oldval;
 684          if (DEBUG_GetWatchedValue(i, &val)) {
 685             breakpoints[i].u.w.oldval = val;
 686             return i;
 687          }
 688       }
 689    }
 690
 691    /* Method 1 failed, trying method 2 */
 692
 693    /* Method 2 => check if value has changed among registered watchpoints
 694     * this really sucks, but this is how gdb 4.18 works on my linux box
 695     * -EP
 696     */
 697    for (i = 0; i < next_bp; i++)
 698    {
 699       DWORD val = 0;
 700
 701       if (breakpoints[i].refcount && breakpoints[i].enabled &&
 702           breakpoints[i].type == DBG_WATCH &&
 703           DEBUG_GetWatchedValue(i, &val))
 704       {
 705          *oldval = breakpoints[i].u.w.oldval;
 706          if (val != *oldval)
 707          {
 708             DEBUG_context.Dr6 &= ~(1 << breakpoints[i].u.w.reg);
 709             breakpoints[i].u.w.oldval = val;
 710             found = i;
 711             /* cannot break, because two watch points may have been triggered on
 712              * the same access
 713              * only one will be reported to the user (FIXME ?)
 714              */
 715          }
 716       }
 717    }
 718 #endif
 719    return found;
 720 }
 721
 722 /***********************************************************************
 723  *           DEBUG_InfoBreakpoints
 724  *
 725  * Display break points information.
 726  */
 727 void DEBUG_InfoBreakpoints(void)
 728 {
 729     int i;
 730
 731     DEBUG_Printf( DBG_CHN_MESG, "Breakpoints:\n" );
 732     for (i = 1; i < next_bp; i++)
 733     {
 734         if (breakpoints[i].refcount && breakpoints[i].type == DBG_BREAK)
 735         {
 736             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 737             DEBUG_PrintAddress( &breakpoints[i].addr,
 738                                 breakpoints[i].is32 ? MODE_32 : MODE_16, TRUE);
 739             DEBUG_Printf( DBG_CHN_MESG, " (%u)\n", breakpoints[i].refcount );
 740             if( breakpoints[i].condition != NULL )
 741             {
 742                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 743                 DEBUG_DisplayExpr(breakpoints[i].condition);
 744                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 745             }
 746         }
 747     }
 748     DEBUG_Printf( DBG_CHN_MESG, "Watchpoints:\n" );
 749     for (i = 1; i < next_bp; i++)
 750     {
 751         if (breakpoints[i].refcount && breakpoints[i].type == DBG_WATCH)
 752         {
 753             DEBUG_Printf( DBG_CHN_MESG, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
 754             DEBUG_PrintAddress( &breakpoints[i].addr,
 755                                 breakpoints[i].is32 ? MODE_32 : MODE_16, TRUE);
 756             DEBUG_Printf( DBG_CHN_MESG, " on %d byte%s (%c)\n",
 757                      breakpoints[i].u.w.len + 1,
 758                      breakpoints[i].u.w.len > 0 ? "s" : "",
 759                      breakpoints[i].u.w.rw ? 'W' : 'R');
 760             if( breakpoints[i].condition != NULL )
 761             {
 762                 DEBUG_Printf(DBG_CHN_MESG, "\t\tstop when  ");
 763                 DEBUG_DisplayExpr(breakpoints[i].condition);
 764                 DEBUG_Printf(DBG_CHN_MESG, "\n");
 765             }
 766         }
 767     }
 768 }
 769
 770 /***********************************************************************
 771  *           DEBUG_ShallBreak
 772  *
 773  * Check whether or not the condition (bp / skipcount) of a break/watch
 774  * point are met.
 775  */
 776 static  BOOL DEBUG_ShallBreak( int bpnum )
 777 {
 778     if ( breakpoints[bpnum].condition != NULL )
 779     {
 780         DBG_VALUE value = DEBUG_EvalExpr(breakpoints[bpnum].condition);
 781
 782         if ( value.type == NULL )
 783         {
 784             /*
 785              * Something wrong - unable to evaluate this expression.
 786              */
 787             DEBUG_Printf(DBG_CHN_MESG, "Unable to evaluate expression ");
 788             DEBUG_DisplayExpr(breakpoints[bpnum].condition);
 789             DEBUG_Printf(DBG_CHN_MESG, "\nTurning off condition\n");
 790             DEBUG_AddBPCondition(bpnum, NULL);
 791         }
 792         else if( !DEBUG_GetExprValue( &value, NULL) )
 793         {
 794             return FALSE;
 795         }
 796     }
 797
 798     if ( breakpoints[bpnum].skipcount > 0 && --breakpoints[bpnum].skipcount > 0 )
 799         return FALSE;
 800
 801    if ((breakpoints[bpnum].type == DBG_BREAK) && breakpoints[bpnum].u.b.func)
 802        return breakpoints[bpnum].u.b.func();
 803    return TRUE;
 804 }
 805
 806 /***********************************************************************
 807  *           DEBUG_ShouldContinue
 808  *
 809  * Determine if we should continue execution after a SIGTRAP signal when
 810  * executing in the given mode.
 811  */
 812 BOOL DEBUG_ShouldContinue( DBG_ADDR *addr, DWORD code, int * count )
 813 {
 814     int                 bpnum;
 815     DWORD               oldval;
 816     int                 wpnum;
 817     enum dbg_mode       addr_mode;
 818     struct symbol_info  syminfo;
 819     enum exec_mode      mode = DEBUG_CurrThread->exec_mode;
 820
 821 #ifdef __i386__
 822     /* If not single-stepping, back up over the int3 instruction */
 823     if (code == EXCEPTION_BREAKPOINT)
 824     {
 825        DEBUG_context.Eip--;
 826        addr->off--;
 827     }
 828 #endif
 829
 830     bpnum = DEBUG_FindBreakpoint( addr, DBG_BREAK );
 831     breakpoints[0].enabled = FALSE;  /* disable the step-over breakpoint */
 832
 833     if ((bpnum != 0) && (bpnum != -1))
 834     {
 835         if (!DEBUG_ShallBreak(bpnum)) return TRUE;
 836
 837         DEBUG_Printf( DBG_CHN_MESG, "Stopped on breakpoint %d at ", bpnum );
 838         syminfo = DEBUG_PrintAddress( &breakpoints[bpnum].addr,
 839                                       breakpoints[bpnum].is32 ? MODE_32 : MODE_16, TRUE );
 840         DEBUG_Printf( DBG_CHN_MESG, "\n" );
 841
 842         if( syminfo.list.sourcefile != NULL )
 843             DEBUG_List(&syminfo.list, NULL, 0);
 844         return FALSE;
 845     }
 846
 847     wpnum = DEBUG_FindTriggeredWatchpoint(&oldval);
 848     if ((wpnum != 0) && (wpnum != -1))
 849     {
 850        /* If not single-stepping, do not back up over the int3 instruction */
 851        if (code == EXCEPTION_BREAKPOINT)
 852        {
 853 #ifdef __i386__
 854            DEBUG_context.Eip++;
 855            addr->off++;
 856 #endif
 857        }
 858        if (!DEBUG_ShallBreak(wpnum)) return TRUE;
 859
 860        addr_mode = DEBUG_GetSelectorType( addr->seg );
 861        DEBUG_Printf(DBG_CHN_MESG, "Stopped on watchpoint %d at ", wpnum);
 862        syminfo = DEBUG_PrintAddress( addr, addr_mode, TRUE );
 863
 864        DEBUG_Printf(DBG_CHN_MESG, " values: old=%lu new=%lu\n",
 865                     oldval, breakpoints[wpnum].u.w.oldval);
 866        if (syminfo.list.sourcefile != NULL)
 867           DEBUG_List(&syminfo.list, NULL, 0);
 868        return FALSE;
 869     }
 870
 871     /*
 872      * If our mode indicates that we are stepping line numbers,
 873      * get the current function, and figure out if we are exactly
 874      * on a line number or not.
 875      */
 876     if( mode == EXEC_STEP_OVER || mode == EXEC_STEP_INSTR )
 877     {
 878         if( DEBUG_CheckLinenoStatus(addr) == AT_LINENUMBER )
 879         {
 880             (*count)--;
 881         }
 882     }
 883     else if( mode == EXEC_STEPI_OVER || mode == EXEC_STEPI_INSTR )
 884     {
 885         (*count)--;
 886     }
 887
 888     if( *count > 0 || mode == EXEC_FINISH )
 889     {
 890         /*
 891          * We still need to execute more instructions.
 892          */
 893         return TRUE;
 894     }
 895
 896     /*
 897      * If we are about to stop, then print out the source line if we
 898      * have it.
 899      */
 900     if (mode != EXEC_CONT && mode != EXEC_FINISH)
 901     {
 902         DEBUG_FindNearestSymbol(addr, TRUE, NULL, 0, &syminfo.list);
 903         if (syminfo.list.sourcefile != NULL)
 904         {
 905             DEBUG_List(&syminfo.list, NULL, 0);
 906         }
 907     }
 908
 909 #ifdef __i386__
 910     /* If there's no breakpoint and we are not single-stepping, then
 911      * either we must have encountered an int3 in the Windows program
 912      * or someone is trying to stop us
 913      * If the later, (no int3 opcode at current address) then stop,
 914      * otherwise, let's skip it.
 915      */
 916     if ((bpnum == -1) && code == EXCEPTION_BREAKPOINT)
 917     {
 918         unsigned char   c;
 919
 920         if (!DEBUG_READ_MEM(&addr, &c, 1)) c = 0xCC;
 921         DEBUG_context.Eip++;
 922         addr->off++;
 923         if (c != 0xCC) return FALSE;
 924     }
 925 #endif
 926
 927     /* no breakpoint, continue if in continuous mode */
 928     return (mode == EXEC_CONT || mode == EXEC_FINISH);
 929 }
 930
 931 /***********************************************************************
 932  *           DEBUG_SuspendExecution
 933  *
 934  * Remove all breakpoints before entering the debug loop
 935  */
 936 void    DEBUG_SuspendExecution( void )
 937 {
 938    DEBUG_SetBreakpoints( FALSE );
 939    breakpoints[0] = DEBUG_CurrThread->stepOverBP;
 940 }
 941
 942 /***********************************************************************
 943  *           DEBUG_RestartExecution
 944  *
 945  * Set the breakpoints to the correct state to restart execution
 946  * in the given mode.
 947  */
 948 void DEBUG_RestartExecution( int count )
 949 {
 950     DBG_ADDR addr;
 951     DBG_ADDR addr2;
 952     int bp;
 953     int delta;
 954     int status;
 955     enum exec_mode mode, ret_mode;
 956     DWORD instr;
 957     unsigned char ch;
 958
 959     DEBUG_GetCurrentAddress( &addr );
 960
 961     /*
 962      * This is the mode we will be running in after we finish.  We would like
 963      * to be able to modify this in certain cases.
 964      */
 965     ret_mode = mode = DEBUG_CurrThread->exec_mode;
 966
 967     bp = DEBUG_FindBreakpoint( &addr, DBG_BREAK );
 968     if ( bp != -1 && bp != 0)
 969       {
 970         /*
 971          * If we have set a new value, then save it in the BP number.
 972          */
 973         if( count != 0 && mode == EXEC_CONT )
 974           {
 975             breakpoints[bp].skipcount = count;
 976           }
 977         mode = EXEC_STEPI_INSTR;  /* If there's a breakpoint, skip it */
 978       }
 979     else
 980       {
 981         if( mode == EXEC_CONT && count > 1 )
 982           {
 983             DEBUG_Printf(DBG_CHN_MESG, "Not stopped at any breakpoint; argument ignored.\n");
 984           }
 985       }
 986
 987     if( mode == EXEC_FINISH && DEBUG_IsFctReturn() )
 988       {
 989         mode = ret_mode = EXEC_STEPI_INSTR;
 990       }
 991
 992     instr = DEBUG_ToLinear( &addr );
 993     DEBUG_READ_MEM((void*)instr, &ch, sizeof(ch));
 994     /*
 995      * See if the function we are stepping into has debug info
 996      * and line numbers.  If not, then we step over it instead.
 997      * FIXME - we need to check for things like thunks or trampolines,
 998      * as the actual function may in fact have debug info.
 999      */
1000     if ( ch == 0xe8 )
1001       {
1002         DEBUG_READ_MEM((void*)(instr + 1), &delta, sizeof(delta));
1003         addr2 = addr;
1004         DEBUG_Disasm(&addr2, FALSE);
1005         addr2.off += delta;
1006
1007         status = DEBUG_CheckLinenoStatus(&addr2);
1008         /*
1009          * Anytime we have a trampoline, step over it.
1010          */
1011         if( ((mode == EXEC_STEP_OVER) || (mode == EXEC_STEPI_OVER))
1012             && status == FUNC_IS_TRAMPOLINE )
1013           {
1014 #if 0
1015             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into trampoline at %x (no lines)\n",
1016                     addr2.off);
1017 #endif
1018             mode = EXEC_STEP_OVER_TRAMPOLINE;
1019           }
1020
1021         if( mode == EXEC_STEP_INSTR && status == FUNC_HAS_NO_LINES )
1022           {
1023 #if 0
1024             DEBUG_Printf(DBG_CHN_MESG, "Not stepping into function at %x (no lines)\n",
1025                     addr2.off);
1026 #endif
1027             mode = EXEC_STEP_OVER;
1028           }
1029       }
1030
1031
1032     if( mode == EXEC_STEP_INSTR )
1033       {
1034         if( DEBUG_CheckLinenoStatus(&addr) == FUNC_HAS_NO_LINES )
1035           {
1036             DEBUG_Printf(DBG_CHN_MESG, "Single stepping until exit from function, \n");
1037             DEBUG_Printf(DBG_CHN_MESG, "which has no line number information.\n");
1038
1039             ret_mode = mode = EXEC_FINISH;
1040           }
1041       }
1042
1043     switch(mode)
1044     {
1045     case EXEC_CONT: /* Continuous execution */
1046 #ifdef __i386__
1047         DEBUG_context.EFlags &= ~STEP_FLAG;
1048 #endif
1049         DEBUG_SetBreakpoints( TRUE );
1050         break;
1051
1052     case EXEC_STEP_OVER_TRAMPOLINE:
1053       /*
1054        * This is the means by which we step over our conversion stubs
1055        * in callfrom*.s and callto*.s.  We dig the appropriate address
1056        * off the stack, and we set the breakpoint there instead of the
1057        * address just after the call.
1058        */
1059 #ifdef __i386__
1060       DEBUG_READ_MEM((void*)(DEBUG_context.Esp +
1061                              2 * sizeof(unsigned int)),
1062                      &addr.off, sizeof(addr.off));
1063       DEBUG_context.EFlags &= ~STEP_FLAG;
1064 #endif
1065       breakpoints[0].addr    = addr;
1066       breakpoints[0].enabled = TRUE;
1067       breakpoints[0].refcount = 1;
1068       breakpoints[0].skipcount = 0;
1069       DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
1070                      sizeof(char));
1071       DEBUG_SetBreakpoints( TRUE );
1072       break;
1073
1074     case EXEC_FINISH:
1075     case EXEC_STEPI_OVER:  /* Stepping over a call */
1076     case EXEC_STEP_OVER:  /* Stepping over a call */
1077         if (DEBUG_IsStepOverInstr())
1078         {
1079 #ifdef __i386__
1080             DEBUG_context.EFlags &= ~STEP_FLAG;
1081 #endif
1082             DEBUG_Disasm(&addr, FALSE);
1083             breakpoints[0].addr    = addr;
1084             breakpoints[0].enabled = TRUE;
1085             breakpoints[0].refcount = 1;
1086             breakpoints[0].skipcount = 0;
1087             DEBUG_READ_MEM((void*)DEBUG_ToLinear( &addr ), &breakpoints[0].u.b.opcode,
1088                            sizeof(char));
1089             DEBUG_SetBreakpoints( TRUE );
1090             break;
1091         }
1092         /* else fall through to single-stepping */
1093
1094     case EXEC_STEP_INSTR: /* Single-stepping an instruction */
1095     case EXEC_STEPI_INSTR: /* Single-stepping an instruction */
1096 #ifdef __i386__
1097         DEBUG_context.EFlags |= STEP_FLAG;
1098 #endif
1099         break;
1100     default:
1101         RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
1102     }
1103     DEBUG_CurrThread->stepOverBP = breakpoints[0];
1104     DEBUG_CurrThread->exec_mode = ret_mode;
1105 }
1106
1107 int
1108 DEBUG_AddBPCondition(int num, struct expr * exp)
1109 {
1110     if ((num <= 0) || (num >= next_bp) || !breakpoints[num].refcount)
1111     {
1112         DEBUG_Printf( DBG_CHN_MESG, "Invalid breakpoint number %d\n", num );
1113         return FALSE;
1114     }
1115
1116     if( breakpoints[num].condition != NULL )
1117       {
1118         DEBUG_FreeExpr(breakpoints[num].condition);
1119         breakpoints[num].condition = NULL;
1120       }
1121
1122     if( exp != NULL )
1123       {
1124         breakpoints[num].condition = DEBUG_CloneExpr(exp);
1125       }
1126
1127    return TRUE;
1128 }