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_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( DEBUG_CurrThread->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(BOOL noisy)
 178 {
 179 #ifdef __i386
 180     DBG_ADDR            addr, sw_addr, code, tmp;
 181     unsigned int        ss = DEBUG_context.SegSs;
 182     unsigned int        cs = DEBUG_context.SegCs;
 183     int                 frameno = 0, is16, ok;
 184     DWORD               next_switch, cur_switch, p;
 185     STACK16FRAME        frame16;
 186     STACK32FRAME        frame32;
 187     char                ch;
 188
 189     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Backtrace:\n" );
 190
 191     nframe = 0;
 192     if (frames) DBG_free( frames );
 193     /* frames = (struct bt_info *) DBG_alloc( sizeof(struct bt_info) ); */
 194     frames = NULL;
 195
 196     if (DEBUG_IsSelectorSystem(ss)) ss = 0;
 197     if (DEBUG_IsSelectorSystem(cs)) cs = 0;
 198
 199     /* first stack frame from registers */
 200     switch (DEBUG_GetSelectorType(ss))
 201     {
 202     case MODE_32:
 203         code.seg = cs;
 204         code.off = DEBUG_context.Eip;
 205         addr.seg = ss;
 206         addr.off = DEBUG_context.Ebp;
 207         DEBUG_ForceFrame( &addr, &code, frameno, MODE_32, noisy, NULL );
 208         if (!(code.seg || code.off)) {
 209             /* trying to execute a null pointer... yuck...
 210              * if it was a call to null, the return EIP should be
 211              * available at SS:ESP, so let's try to retrieve it */
 212             tmp.seg = ss;
 213             tmp.off = DEBUG_context.Esp;
 214             if (DEBUG_READ_MEM((void *)DEBUG_ToLinear(&tmp), &code.off, sizeof(code.off))) {
 215                 DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, ", null call assumed" );
 216             }
 217         }
 218         is16 = FALSE;
 219         break;
 220     case MODE_16:
 221     case MODE_VM86:
 222         code.seg = cs;
 223         code.off = LOWORD(DEBUG_context.Eip);
 224         addr.seg = ss;
 225         addr.off = LOWORD(DEBUG_context.Ebp);
 226         DEBUG_ForceFrame( &addr, &code, frameno, MODE_16, noisy, NULL );
 227         is16 = TRUE;
 228         break;
 229     default:
 230         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad segment '%x'\n", ss);
 231         return;
 232     }
 233
 234     /* cur_switch holds address of curr_stack's field in TEB in debuggee
 235      * address space
 236      */
 237     cur_switch = (DWORD)DEBUG_CurrThread->teb + OFFSET_OF(TEB, cur_stack);
 238     if (!DEBUG_READ_MEM((void*)cur_switch, &next_switch, sizeof(next_switch))) {
 239         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Can't read TEB:cur_stack\n");
 240         return;
 241     }
 242
 243     if (is16) {
 244         if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 245             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 246                                      (unsigned long)(STACK32FRAME*)next_switch );
 247             return;
 248         }
 249         cur_switch = (DWORD)frame32.frame16;
 250         sw_addr.seg = SELECTOROF(cur_switch);
 251         sw_addr.off = OFFSETOF(cur_switch);
 252     } else {
 253         tmp.seg = SELECTOROF(next_switch);
 254         tmp.off = OFFSETOF(next_switch);
 255         p = DEBUG_ToLinear(&tmp);
 256
 257         if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 258             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 259                                      (unsigned long)(STACK16FRAME*)p );
 260             return;
 261         }
 262         cur_switch = (DWORD)frame16.frame32;
 263         sw_addr.seg = ss;
 264         sw_addr.off = cur_switch;
 265     }
 266     if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 267         sw_addr.seg = (DWORD)-1;
 268         sw_addr.off = (DWORD)-1;
 269     }
 270
 271     for (ok = TRUE; ok;) {
 272         if ((frames[frameno].ss == sw_addr.seg) &&
 273             sw_addr.off && (frames[frameno].ebp >= sw_addr.off))
 274         {
 275            /* 16<->32 switch...
 276             * yes, I know this is confusing, it gave me a headache too */
 277            if (is16) {
 278
 279                if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 280                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 281                                            (unsigned long)(STACK32FRAME*)next_switch );
 282                   return;
 283                }
 284
 285                code.seg  = 0;
 286                code.off  = frame32.retaddr;
 287
 288                cs = 0;
 289                addr.seg = 0;
 290                addr.off = frame32.ebp;
 291                DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, NULL );
 292
 293                next_switch = cur_switch;
 294                tmp.seg = SELECTOROF(next_switch);
 295                tmp.off = OFFSETOF(next_switch);
 296                p = DEBUG_ToLinear(&tmp);
 297
 298                if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 299                    if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 300                                             (unsigned long)(STACK16FRAME*)p );
 301                    return;
 302                }
 303                cur_switch = (DWORD)frame16.frame32;
 304                sw_addr.seg = 0;
 305                sw_addr.off = cur_switch;
 306
 307                is16 = FALSE;
 308            } else {
 309               tmp.seg = SELECTOROF(next_switch);
 310               tmp.off = OFFSETOF(next_switch);
 311               p = DEBUG_ToLinear(&tmp);
 312
 313               if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 314                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 315                                            (unsigned long)(STACK16FRAME*)p );
 316                   return;
 317               }
 318
 319               code.seg  = frame16.cs;
 320               code.off  = frame16.ip;
 321
 322               cs = frame16.cs;
 323               addr.seg = SELECTOROF(next_switch);
 324               addr.off = frame16.bp;
 325               DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_16, noisy, NULL );
 326
 327               next_switch = cur_switch;
 328               if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 329                  if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 330                                           (unsigned long)(STACK32FRAME*)next_switch );
 331                  return;
 332               }
 333               cur_switch = (DWORD)frame32.frame16;
 334               sw_addr.seg = SELECTOROF(cur_switch);
 335               sw_addr.off = OFFSETOF(cur_switch);
 336
 337               is16 = TRUE;
 338            }
 339            if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 340               sw_addr.seg = (DWORD)-1;
 341               sw_addr.off = (DWORD)-1;
 342            }
 343         } else {
 344             /* ordinary stack frame */
 345            ok = is16 ? DEBUG_Frame16( &addr, &cs, ++frameno, noisy)
 346               : DEBUG_Frame32( &addr, &cs, ++frameno, noisy);
 347         }
 348     }
 349     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "\n" );
 350 #endif
 351 }
 352
 353 int
 354 DEBUG_SetFrame(int newframe)
 355 {
 356 #ifdef __i386__
 357   int           rtn = FALSE;
 358
 359   curr_frame = newframe;
 360
 361   if( curr_frame >= nframe )
 362     {
 363       curr_frame = nframe - 1;
 364     }
 365
 366   if( curr_frame < 0 )
 367     {
 368       curr_frame = 0;
 369     }
 370
 371    if( frames && frames[curr_frame].frame.list.sourcefile != NULL )
 372     {
 373       DEBUG_List(&frames[curr_frame].frame.list, NULL, 0);
 374     }
 375
 376   rtn = TRUE;
 377   return (rtn);
 378 #else /* __i386__ */
 379   return FALSE;
 380 #endif /* __i386__ */
 381 }
 382
 383 int
 384 DEBUG_GetCurrentFrame(struct name_hash ** name, unsigned int * eip,
 385                       unsigned int * ebp)
 386 {
 387 #ifdef __i386__
 388   /*
 389    * If we don't have a valid backtrace, then just return.
 390    */
 391   if( frames == NULL )
 392     {
 393       return FALSE;
 394     }
 395
 396   /*
 397    * If we don't know what the current function is, then we also have
 398    * nothing to report here.
 399    */
 400   if( frames[curr_frame].frame.sym == NULL )
 401     {
 402       return FALSE;
 403     }
 404
 405   *name = frames[curr_frame].frame.sym;
 406   *eip = frames[curr_frame].eip;
 407   *ebp = frames[curr_frame].ebp;
 408
 409   return TRUE;
 410 #else /* __i386__ */
 411   return FALSE;
 412 #endif /* __i386__ */
 413 }
 414