debugger/stack.c

   1 /*
   2  * Debugger stack handling
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 1996 Eric Youngdale
   6  * Copyright 1999 Ove Kåven
   7  */
   8
   9 #include "config.h"
  10
  11 #include <stdlib.h>
  12
  13 #include "debugger.h"
  14 #include "stackframe.h"
  15 #include "winbase.h"
  16
  17 #ifdef __i386__
  18 /*
  19  * We keep this info for each frame, so that we can
  20  * find local variable information correctly.
  21  */
  22 struct bt_info
  23 {
  24   unsigned int       cs;
  25   unsigned int       eip;
  26   unsigned int       ss;
  27   unsigned int       ebp;
  28   struct symbol_info frame;
  29 };
  30
  31 static int nframe;
  32 static struct bt_info * frames = NULL;
  33
  34 typedef struct
  35 {
  36     WORD bp;
  37     WORD ip;
  38     WORD cs;
  39 } FRAME16;
  40
  41 typedef struct
  42 {
  43     DWORD bp;
  44     DWORD ip;
  45     WORD cs;
  46 } FRAME32;
  47 #endif
  48
  49
  50 /***********************************************************************
  51  *           DEBUG_InfoStack
  52  *
  53  * Dump the top of the stack
  54  */
  55 void DEBUG_InfoStack(void)
  56 {
  57 #ifdef __i386__
  58     DBG_VALUE   value;
  59
  60     value.type = NULL;
  61     value.cookie = DV_TARGET;
  62     value.addr.seg = DEBUG_context.SegSs;
  63     value.addr.off = DEBUG_context.Esp;
  64
  65     DEBUG_Printf(DBG_CHN_MESG,"Stack dump:\n");
  66     switch (DEBUG_GetSelectorType(value.addr.seg))
  67     {
  68     case MODE_32: /* 32-bit mode */
  69        DEBUG_ExamineMemory( &value, 24, 'x' );
  70        break;
  71     case MODE_16:  /* 16-bit mode */
  72     case MODE_VM86:
  73         value.addr.off &= 0xffff;
  74         DEBUG_ExamineMemory( &value, 24, 'w' );
  75         break;
  76     default:
  77        DEBUG_Printf(DBG_CHN_MESG, "Bad segment (%ld)\n", value.addr.seg);
  78     }
  79     DEBUG_Printf(DBG_CHN_MESG,"\n");
  80 #endif
  81 }
  82
  83 #ifdef __i386__
  84 static void DEBUG_ForceFrame(DBG_ADDR *stack, DBG_ADDR *code, int frameno, enum dbg_mode mode,
  85                              int noisy, const char *caveat)
  86 {
  87     int theframe = nframe++;
  88     frames = (struct bt_info *)DBG_realloc(frames,
  89                                            nframe*sizeof(struct bt_info));
  90     if (noisy)
  91       DEBUG_Printf(DBG_CHN_MESG,"%s%d ", (theframe == curr_frame ? "=>" : "  "),
  92               frameno);
  93     frames[theframe].cs = code->seg;
  94     frames[theframe].eip = code->off;
  95     if (noisy)
  96         frames[theframe].frame = DEBUG_PrintAddressAndArgs( code, mode, stack->off, TRUE );
  97     else
  98       DEBUG_FindNearestSymbol( code, TRUE,
  99                                &frames[theframe].frame.sym, stack->off,
 100                                &frames[theframe].frame.list);
 101     frames[theframe].ss = stack->seg;
 102     frames[theframe].ebp = stack->off;
 103     if (noisy) {
 104       DEBUG_Printf( DBG_CHN_MESG, (mode != MODE_32) ? " (bp=%04lx%s)\n" : " (ebp=%08lx%s)\n",
 105                     stack->off, caveat?caveat:"" );
 106     }
 107 }
 108
 109 static BOOL DEBUG_Frame16(DBG_THREAD* thread, DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
 110 {
 111     unsigned int        possible_cs = 0;
 112     FRAME16             frame;
 113     void*               p = (void*)DEBUG_ToLinear(addr);
 114     DBG_ADDR            code;
 115
 116     if (!p) return FALSE;
 117
 118     if (!DEBUG_READ_MEM(p, &frame, sizeof(frame))) {
 119         if (noisy) DEBUG_InvalAddr(addr);
 120         return FALSE;
 121     }
 122     if (!frame.bp) return FALSE;
 123
 124     if (frame.bp & 1) *cs = frame.cs;
 125     else {
 126         /* not explicitly marked as far call,
 127          * but check whether it could be anyway */
 128         if (((frame.cs&7)==7) && (frame.cs != *cs)) {
 129             LDT_ENTRY   le;
 130
 131             if (GetThreadSelectorEntry( thread->handle, frame.cs, &le) &&
 132                 (le.HighWord.Bits.Type & 0x08)) { /* code segment */
 133                 /* it is very uncommon to push a code segment cs as
 134                  * a parameter, so this should work in most cases */
 135                 *cs = possible_cs = frame.cs;
 136             }
 137         }
 138     }
 139     code.seg = *cs;
 140     code.off = frame.ip;
 141     addr->off = frame.bp & ~1;
 142     DEBUG_ForceFrame(addr, &code, frameno, MODE_16, noisy,
 143                      possible_cs ? ", far call assumed" : NULL );
 144     return TRUE;
 145 }
 146
 147 static BOOL DEBUG_Frame32(DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
 148 {
 149     FRAME32             frame;
 150     void*               p = (void*)DEBUG_ToLinear(addr);
 151     DBG_ADDR            code;
 152     DWORD               old_bp = addr->off;
 153
 154     if (!p) return FALSE;
 155
 156     if (!DEBUG_READ_MEM(p, &frame, sizeof(frame))) {
 157        if (noisy) DEBUG_InvalAddr(addr);
 158        return FALSE;
 159     }
 160     if (!frame.ip) return FALSE;
 161
 162     code.seg = *cs;
 163     code.off = frame.ip;
 164     addr->off = frame.bp;
 165     DEBUG_ForceFrame(addr, &code, frameno, MODE_32, noisy, NULL);
 166     if (addr->off == old_bp) return FALSE;
 167     return TRUE;
 168 }
 169 #endif
 170
 171
 172 /***********************************************************************
 173  *           DEBUG_BackTrace
 174  *
 175  * Display a stack back-trace.
 176  */
 177 void DEBUG_BackTrace(DWORD tid, BOOL noisy)
 178 {
 179 #ifdef __i386
 180     DBG_ADDR            addr, sw_addr, code, tmp;
 181     unsigned int        ss, cs;
 182     int                 frameno = 0, is16, ok;
 183     DWORD               next_switch, cur_switch, p;
 184     STACK16FRAME        frame16;
 185     STACK32FRAME        frame32;
 186     char                ch;
 187     CONTEXT             ctx;
 188     DBG_THREAD*         thread;
 189
 190     int                 copy_nframe = 0;
 191     int                 copy_curr_frame = 0;
 192     struct bt_info*     copy_frames = NULL;
 193
 194     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Backtrace:\n" );
 195
 196     if (tid == DEBUG_CurrTid)
 197     {
 198          ctx = DEBUG_context;
 199          thread = DEBUG_CurrThread;
 200
 201          if (frames) DBG_free( frames );
 202          /* frames = (struct bt_info *) DBG_alloc( sizeof(struct bt_info) ); */
 203     }
 204     else
 205     {
 206          thread = DEBUG_GetThread(DEBUG_CurrProcess, tid);
 207
 208          if (!thread)
 209          {
 210               DEBUG_Printf( DBG_CHN_MESG, "Unknown thread id (0x%08lx) in current process\n", tid);
 211               return;
 212          }
 213          memset(&ctx, 0, sizeof(ctx));
 214          ctx.ContextFlags = CONTEXT_CONTROL | CONTEXT_SEGMENTS;
 215
 216          if ( SuspendThread( thread->handle ) == -1 ||
 217               !GetThreadContext( thread->handle, &ctx ))
 218          {
 219               DEBUG_Printf( DBG_CHN_MESG, "Can't get context for thread id (0x%08lx) in current process\n", tid);
 220               return;
 221          }
 222          /* need to avoid trashing stack frame for current thread */
 223          copy_nframe = nframe;
 224          copy_frames = frames;
 225          copy_curr_frame = curr_frame;
 226          curr_frame = 0;
 227     }
 228
 229     nframe = 0;
 230     frames = NULL;
 231
 232     cs = ctx.SegCs;
 233     ss = ctx.SegSs;
 234
 235     if (DEBUG_IsSelectorSystem(ss)) ss = 0;
 236     if (DEBUG_IsSelectorSystem(cs)) cs = 0;
 237
 238     /* first stack frame from registers */
 239     switch (DEBUG_GetSelectorType(ss))
 240     {
 241     case MODE_32:
 242         code.seg = cs;
 243         code.off = ctx.Eip;
 244         addr.seg = ss;
 245         addr.off = ctx.Ebp;
 246         DEBUG_ForceFrame( &addr, &code, frameno, MODE_32, noisy, NULL );
 247         if (!(code.seg || code.off)) {
 248             /* trying to execute a null pointer... yuck...
 249              * if it was a call to null, the return EIP should be
 250              * available at SS:ESP, so let's try to retrieve it */
 251             tmp.seg = ss;
 252             tmp.off = ctx.Esp;
 253             if (DEBUG_READ_MEM((void *)DEBUG_ToLinear(&tmp), &code.off, sizeof(code.off))) {
 254                 DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, ", null call assumed" );
 255             }
 256         }
 257         is16 = FALSE;
 258         break;
 259     case MODE_16:
 260     case MODE_VM86:
 261         code.seg = cs;
 262         code.off = LOWORD(ctx.Eip);
 263         addr.seg = ss;
 264         addr.off = LOWORD(ctx.Ebp);
 265         DEBUG_ForceFrame( &addr, &code, frameno, MODE_16, noisy, NULL );
 266         is16 = TRUE;
 267         break;
 268     default:
 269         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad segment '%x'\n", ss);
 270         return;
 271     }
 272
 273     /* cur_switch holds address of curr_stack's field in TEB in debuggee
 274      * address space
 275      */
 276     cur_switch = (DWORD)thread->teb + OFFSET_OF(TEB, cur_stack);
 277     if (!DEBUG_READ_MEM((void*)cur_switch, &next_switch, sizeof(next_switch))) {
 278         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Can't read TEB:cur_stack\n");
 279         return;
 280     }
 281
 282     if (is16) {
 283         if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 284             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 285                                      (unsigned long)(STACK32FRAME*)next_switch );
 286             return;
 287         }
 288         cur_switch = (DWORD)frame32.frame16;
 289         sw_addr.seg = SELECTOROF(cur_switch);
 290         sw_addr.off = OFFSETOF(cur_switch);
 291     } else {
 292         tmp.seg = SELECTOROF(next_switch);
 293         tmp.off = OFFSETOF(next_switch);
 294         p = DEBUG_ToLinear(&tmp);
 295
 296         if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 297             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 298                                      (unsigned long)(STACK16FRAME*)p );
 299             return;
 300         }
 301         cur_switch = (DWORD)frame16.frame32;
 302         sw_addr.seg = ss;
 303         sw_addr.off = cur_switch;
 304     }
 305     if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 306         sw_addr.seg = (DWORD)-1;
 307         sw_addr.off = (DWORD)-1;
 308     }
 309
 310     for (ok = TRUE; ok;) {
 311         if ((frames[frameno].ss == sw_addr.seg) &&
 312             sw_addr.off && (frames[frameno].ebp >= sw_addr.off))
 313         {
 314            /* 16<->32 switch...
 315             * yes, I know this is confusing, it gave me a headache too */
 316            if (is16) {
 317
 318                if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 319                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 320                                            (unsigned long)(STACK32FRAME*)next_switch );
 321                   return;
 322                }
 323
 324                code.seg  = 0;
 325                code.off  = frame32.retaddr;
 326
 327                cs = 0;
 328                addr.seg = 0;
 329                addr.off = frame32.ebp;
 330                DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, NULL );
 331
 332                next_switch = cur_switch;
 333                tmp.seg = SELECTOROF(next_switch);
 334                tmp.off = OFFSETOF(next_switch);
 335                p = DEBUG_ToLinear(&tmp);
 336
 337                if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 338                    if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 339                                             (unsigned long)(STACK16FRAME*)p );
 340                    return;
 341                }
 342                cur_switch = (DWORD)frame16.frame32;
 343                sw_addr.seg = 0;
 344                sw_addr.off = cur_switch;
 345
 346                is16 = FALSE;
 347            } else {
 348               tmp.seg = SELECTOROF(next_switch);
 349               tmp.off = OFFSETOF(next_switch);
 350               p = DEBUG_ToLinear(&tmp);
 351
 352               if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 353                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 354                                            (unsigned long)(STACK16FRAME*)p );
 355                   return;
 356               }
 357
 358               code.seg  = frame16.cs;
 359               code.off  = frame16.ip;
 360
 361               cs = frame16.cs;
 362               addr.seg = SELECTOROF(next_switch);
 363               addr.off = frame16.bp;
 364               DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_16, noisy, NULL );
 365
 366               next_switch = cur_switch;
 367               if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 368                  if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 369                                           (unsigned long)(STACK32FRAME*)next_switch );
 370                  return;
 371               }
 372               cur_switch = (DWORD)frame32.frame16;
 373               sw_addr.seg = SELECTOROF(cur_switch);
 374               sw_addr.off = OFFSETOF(cur_switch);
 375
 376               is16 = TRUE;
 377            }
 378            if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 379               sw_addr.seg = (DWORD)-1;
 380               sw_addr.off = (DWORD)-1;
 381            }
 382         } else {
 383             /* ordinary stack frame */
 384            ok = is16 ? DEBUG_Frame16( thread, &addr, &cs, ++frameno, noisy)
 385               : DEBUG_Frame32( &addr, &cs, ++frameno, noisy);
 386         }
 387     }
 388     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "\n" );
 389
 390     if (tid != DEBUG_CurrTid)
 391     {
 392          ResumeThread( thread->handle );
 393          /* restore stack frame for current thread */
 394          if (frames) DBG_free( frames );
 395          frames = copy_frames;
 396          nframe = copy_nframe;
 397          curr_frame = copy_curr_frame;
 398     }
 399 #endif
 400 }
 401
 402 int
 403 DEBUG_SetFrame(int newframe)
 404 {
 405 #ifdef __i386__
 406   int           rtn = FALSE;
 407
 408   curr_frame = newframe;
 409
 410   if( curr_frame >= nframe )
 411     {
 412       curr_frame = nframe - 1;
 413     }
 414
 415   if( curr_frame < 0 )
 416     {
 417       curr_frame = 0;
 418     }
 419
 420    if( frames && frames[curr_frame].frame.list.sourcefile != NULL )
 421     {
 422       DEBUG_List(&frames[curr_frame].frame.list, NULL, 0);
 423     }
 424
 425   rtn = TRUE;
 426   return (rtn);
 427 #else /* __i386__ */
 428   return FALSE;
 429 #endif /* __i386__ */
 430 }
 431
 432 int
 433 DEBUG_GetCurrentFrame(struct name_hash ** name, unsigned int * eip,
 434                       unsigned int * ebp)
 435 {
 436 #ifdef __i386__
 437   /*
 438    * If we don't have a valid backtrace, then just return.
 439    */
 440   if( frames == NULL )
 441     {
 442       return FALSE;
 443     }
 444
 445   /*
 446    * If we don't know what the current function is, then we also have
 447    * nothing to report here.
 448    */
 449   if( frames[curr_frame].frame.sym == NULL )
 450     {
 451       return FALSE;
 452     }
 453
 454   *name = frames[curr_frame].frame.sym;
 455   *eip = frames[curr_frame].eip;
 456   *ebp = frames[curr_frame].ebp;
 457
 458   return TRUE;
 459 #else /* __i386__ */
 460   return FALSE;
 461 #endif /* __i386__ */
 462 }
 463