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  * 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
  25 #include <stdlib.h>
  26
  27 #include "debugger.h"
  28 #include "stackframe.h"
  29 #include "winbase.h"
  30
  31 #ifdef __i386__
  32 /*
  33  * We keep this info for each frame, so that we can
  34  * find local variable information correctly.
  35  */
  36 struct bt_info
  37 {
  38   unsigned int       cs;
  39   unsigned int       eip;
  40   unsigned int       ss;
  41   unsigned int       ebp;
  42   struct symbol_info frame;
  43 };
  44
  45 static int nframe;
  46 static struct bt_info * frames = NULL;
  47
  48 typedef struct
  49 {
  50     WORD bp;
  51     WORD ip;
  52     WORD cs;
  53 } FRAME16;
  54
  55 typedef struct
  56 {
  57     DWORD bp;
  58     DWORD ip;
  59     WORD cs;
  60 } FRAME32;
  61 #endif
  62
  63
  64 /***********************************************************************
  65  *           DEBUG_InfoStack
  66  *
  67  * Dump the top of the stack
  68  */
  69 void DEBUG_InfoStack(void)
  70 {
  71 #ifdef __i386__
  72     DBG_VALUE   value;
  73
  74     value.type = NULL;
  75     value.cookie = DV_TARGET;
  76     value.addr.seg = DEBUG_context.SegSs;
  77     value.addr.off = DEBUG_context.Esp;
  78
  79     DEBUG_Printf(DBG_CHN_MESG,"Stack dump:\n");
  80     switch (DEBUG_GetSelectorType(value.addr.seg))
  81     {
  82     case MODE_32: /* 32-bit mode */
  83        DEBUG_ExamineMemory( &value, 24, 'x' );
  84        break;
  85     case MODE_16:  /* 16-bit mode */
  86     case MODE_VM86:
  87         value.addr.off &= 0xffff;
  88         DEBUG_ExamineMemory( &value, 24, 'w' );
  89         break;
  90     default:
  91        DEBUG_Printf(DBG_CHN_MESG, "Bad segment (%ld)\n", value.addr.seg);
  92     }
  93     DEBUG_Printf(DBG_CHN_MESG,"\n");
  94 #endif
  95 }
  96
  97 #ifdef __i386__
  98 static void DEBUG_ForceFrame(DBG_ADDR *stack, DBG_ADDR *code, int frameno, enum dbg_mode mode,
  99                              int noisy, const char *caveat)
 100 {
 101     int theframe = nframe++;
 102     frames = (struct bt_info *)DBG_realloc(frames,
 103                                            nframe*sizeof(struct bt_info));
 104     if (noisy)
 105       DEBUG_Printf(DBG_CHN_MESG,"%s%d ", (theframe == curr_frame ? "=>" : "  "),
 106               frameno);
 107     frames[theframe].cs = code->seg;
 108     frames[theframe].eip = code->off;
 109     if (noisy)
 110         frames[theframe].frame = DEBUG_PrintAddressAndArgs( code, mode, stack->off, TRUE );
 111     else
 112       DEBUG_FindNearestSymbol( code, TRUE,
 113                                &frames[theframe].frame.sym, stack->off,
 114                                &frames[theframe].frame.list);
 115     frames[theframe].ss = stack->seg;
 116     frames[theframe].ebp = stack->off;
 117     if (noisy) {
 118       DEBUG_Printf( DBG_CHN_MESG, (mode != MODE_32) ? " (bp=%04lx%s)\n" : " (ebp=%08lx%s)\n",
 119                     stack->off, caveat?caveat:"" );
 120     }
 121 }
 122
 123 static BOOL DEBUG_Frame16(DBG_THREAD* thread, DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
 124 {
 125     unsigned int        possible_cs = 0;
 126     FRAME16             frame;
 127     void*               p = (void*)DEBUG_ToLinear(addr);
 128     DBG_ADDR            code;
 129
 130     if (!p) return FALSE;
 131
 132     if (!DEBUG_READ_MEM(p, &frame, sizeof(frame))) {
 133         if (noisy) DEBUG_InvalAddr(addr);
 134         return FALSE;
 135     }
 136     if (!frame.bp) return FALSE;
 137
 138     if (frame.bp & 1) *cs = frame.cs;
 139     else {
 140         /* not explicitly marked as far call,
 141          * but check whether it could be anyway */
 142         if (((frame.cs&7)==7) && (frame.cs != *cs)) {
 143             LDT_ENTRY   le;
 144
 145             if (GetThreadSelectorEntry( thread->handle, frame.cs, &le) &&
 146                 (le.HighWord.Bits.Type & 0x08)) { /* code segment */
 147                 /* it is very uncommon to push a code segment cs as
 148                  * a parameter, so this should work in most cases */
 149                 *cs = possible_cs = frame.cs;
 150             }
 151         }
 152     }
 153     code.seg = *cs;
 154     code.off = frame.ip;
 155     addr->off = frame.bp & ~1;
 156     DEBUG_ForceFrame(addr, &code, frameno, MODE_16, noisy,
 157                      possible_cs ? ", far call assumed" : NULL );
 158     return TRUE;
 159 }
 160
 161 static BOOL DEBUG_Frame32(DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
 162 {
 163     FRAME32             frame;
 164     void*               p = (void*)DEBUG_ToLinear(addr);
 165     DBG_ADDR            code;
 166     DWORD               old_bp = addr->off;
 167
 168     if (!p) return FALSE;
 169
 170     if (!DEBUG_READ_MEM(p, &frame, sizeof(frame))) {
 171        if (noisy) DEBUG_InvalAddr(addr);
 172        return FALSE;
 173     }
 174     if (!frame.ip) return FALSE;
 175
 176     code.seg = *cs;
 177     code.off = frame.ip;
 178     addr->off = frame.bp;
 179     DEBUG_ForceFrame(addr, &code, frameno, MODE_32, noisy, NULL);
 180     if (addr->off == old_bp) return FALSE;
 181     return TRUE;
 182 }
 183 #endif
 184
 185
 186 /***********************************************************************
 187  *           DEBUG_BackTrace
 188  *
 189  * Display a stack back-trace.
 190  */
 191 void DEBUG_BackTrace(DWORD tid, BOOL noisy)
 192 {
 193 #ifdef __i386
 194     DBG_ADDR            addr, sw_addr, code, tmp;
 195     unsigned int        ss, cs;
 196     int                 frameno = 0, is16, ok;
 197     DWORD               next_switch, cur_switch, p;
 198     STACK16FRAME        frame16;
 199     STACK32FRAME        frame32;
 200     char                ch;
 201     CONTEXT             ctx;
 202     DBG_THREAD*         thread;
 203
 204     int                 copy_nframe = 0;
 205     int                 copy_curr_frame = 0;
 206     struct bt_info*     copy_frames = NULL;
 207
 208     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Backtrace:\n" );
 209
 210     if (tid == DEBUG_CurrTid)
 211     {
 212          ctx = DEBUG_context;
 213          thread = DEBUG_CurrThread;
 214
 215          if (frames) DBG_free( frames );
 216          /* frames = (struct bt_info *) DBG_alloc( sizeof(struct bt_info) ); */
 217     }
 218     else
 219     {
 220          thread = DEBUG_GetThread(DEBUG_CurrProcess, tid);
 221
 222          if (!thread)
 223          {
 224               DEBUG_Printf( DBG_CHN_MESG, "Unknown thread id (0x%08lx) in current process\n", tid);
 225               return;
 226          }
 227          memset(&ctx, 0, sizeof(ctx));
 228          ctx.ContextFlags = CONTEXT_CONTROL | CONTEXT_SEGMENTS;
 229
 230          if ( SuspendThread( thread->handle ) == -1 ||
 231               !GetThreadContext( thread->handle, &ctx ))
 232          {
 233               DEBUG_Printf( DBG_CHN_MESG, "Can't get context for thread id (0x%08lx) in current process\n", tid);
 234               return;
 235          }
 236          /* need to avoid trashing stack frame for current thread */
 237          copy_nframe = nframe;
 238          copy_frames = frames;
 239          copy_curr_frame = curr_frame;
 240          curr_frame = 0;
 241     }
 242
 243     nframe = 0;
 244     frames = NULL;
 245
 246     cs = ctx.SegCs;
 247     ss = ctx.SegSs;
 248
 249     if (DEBUG_IsSelectorSystem(ss)) ss = 0;
 250     if (DEBUG_IsSelectorSystem(cs)) cs = 0;
 251
 252     /* first stack frame from registers */
 253     switch (DEBUG_GetSelectorType(ss))
 254     {
 255     case MODE_32:
 256         code.seg = cs;
 257         code.off = ctx.Eip;
 258         addr.seg = ss;
 259         addr.off = ctx.Ebp;
 260         DEBUG_ForceFrame( &addr, &code, frameno, MODE_32, noisy, NULL );
 261         if (!(code.seg || code.off)) {
 262             /* trying to execute a null pointer... yuck...
 263              * if it was a call to null, the return EIP should be
 264              * available at SS:ESP, so let's try to retrieve it */
 265             tmp.seg = ss;
 266             tmp.off = ctx.Esp;
 267             if (DEBUG_READ_MEM((void *)DEBUG_ToLinear(&tmp), &code.off, sizeof(code.off))) {
 268                 DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, ", null call assumed" );
 269             }
 270         }
 271         is16 = FALSE;
 272         break;
 273     case MODE_16:
 274     case MODE_VM86:
 275         code.seg = cs;
 276         code.off = LOWORD(ctx.Eip);
 277         addr.seg = ss;
 278         addr.off = LOWORD(ctx.Ebp);
 279         DEBUG_ForceFrame( &addr, &code, frameno, MODE_16, noisy, NULL );
 280         is16 = TRUE;
 281         break;
 282     default:
 283         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad segment '%x'\n", ss);
 284         return;
 285     }
 286
 287     /* cur_switch holds address of curr_stack's field in TEB in debuggee
 288      * address space
 289      */
 290     cur_switch = (DWORD)thread->teb + OFFSET_OF(TEB, cur_stack);
 291     if (!DEBUG_READ_MEM((void*)cur_switch, &next_switch, sizeof(next_switch))) {
 292         if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Can't read TEB:cur_stack\n");
 293         return;
 294     }
 295
 296     if (is16) {
 297         if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 298             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 299                                      (unsigned long)(STACK32FRAME*)next_switch );
 300             return;
 301         }
 302         cur_switch = (DWORD)frame32.frame16;
 303         sw_addr.seg = SELECTOROF(cur_switch);
 304         sw_addr.off = OFFSETOF(cur_switch);
 305     } else {
 306         tmp.seg = SELECTOROF(next_switch);
 307         tmp.off = OFFSETOF(next_switch);
 308         p = DEBUG_ToLinear(&tmp);
 309
 310         if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 311             if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 312                                      (unsigned long)(STACK16FRAME*)p );
 313             return;
 314         }
 315         cur_switch = (DWORD)frame16.frame32;
 316         sw_addr.seg = ss;
 317         sw_addr.off = cur_switch;
 318     }
 319     if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 320         sw_addr.seg = (DWORD)-1;
 321         sw_addr.off = (DWORD)-1;
 322     }
 323
 324     for (ok = TRUE; ok;) {
 325         if ((frames[frameno].ss == sw_addr.seg) &&
 326             sw_addr.off && (frames[frameno].ebp >= sw_addr.off))
 327         {
 328            /* 16<->32 switch...
 329             * yes, I know this is confusing, it gave me a headache too */
 330            if (is16) {
 331
 332                if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 333                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 334                                            (unsigned long)(STACK32FRAME*)next_switch );
 335                   return;
 336                }
 337
 338                code.seg  = 0;
 339                code.off  = frame32.retaddr;
 340
 341                cs = 0;
 342                addr.seg = 0;
 343                addr.off = frame32.ebp;
 344                DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_32, noisy, NULL );
 345
 346                next_switch = cur_switch;
 347                tmp.seg = SELECTOROF(next_switch);
 348                tmp.off = OFFSETOF(next_switch);
 349                p = DEBUG_ToLinear(&tmp);
 350
 351                if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 352                    if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 353                                             (unsigned long)(STACK16FRAME*)p );
 354                    return;
 355                }
 356                cur_switch = (DWORD)frame16.frame32;
 357                sw_addr.seg = 0;
 358                sw_addr.off = cur_switch;
 359
 360                is16 = FALSE;
 361            } else {
 362               tmp.seg = SELECTOROF(next_switch);
 363               tmp.off = OFFSETOF(next_switch);
 364               p = DEBUG_ToLinear(&tmp);
 365
 366               if (!DEBUG_READ_MEM((void*)p, &frame16, sizeof(STACK16FRAME))) {
 367                   if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 368                                            (unsigned long)(STACK16FRAME*)p );
 369                   return;
 370               }
 371
 372               code.seg  = frame16.cs;
 373               code.off  = frame16.ip;
 374
 375               cs = frame16.cs;
 376               addr.seg = SELECTOROF(next_switch);
 377               addr.off = frame16.bp;
 378               DEBUG_ForceFrame( &addr, &code, ++frameno, MODE_16, noisy, NULL );
 379
 380               next_switch = cur_switch;
 381               if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
 382                  if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Bad stack frame 0x%08lx\n",
 383                                           (unsigned long)(STACK32FRAME*)next_switch );
 384                  return;
 385               }
 386               cur_switch = (DWORD)frame32.frame16;
 387               sw_addr.seg = SELECTOROF(cur_switch);
 388               sw_addr.off = OFFSETOF(cur_switch);
 389
 390               is16 = TRUE;
 391            }
 392            if (!DEBUG_READ_MEM((void*)DEBUG_ToLinear(&sw_addr), &ch, sizeof(ch))) {
 393               sw_addr.seg = (DWORD)-1;
 394               sw_addr.off = (DWORD)-1;
 395            }
 396         } else {
 397             /* ordinary stack frame */
 398            ok = is16 ? DEBUG_Frame16( thread, &addr, &cs, ++frameno, noisy)
 399               : DEBUG_Frame32( &addr, &cs, ++frameno, noisy);
 400         }
 401     }
 402     if (noisy) DEBUG_Printf( DBG_CHN_MESG, "\n" );
 403
 404     if (tid != DEBUG_CurrTid)
 405     {
 406          ResumeThread( thread->handle );
 407          /* restore stack frame for current thread */
 408          if (frames) DBG_free( frames );
 409          frames = copy_frames;
 410          nframe = copy_nframe;
 411          curr_frame = copy_curr_frame;
 412     }
 413 #endif
 414 }
 415
 416 int
 417 DEBUG_SetFrame(int newframe)
 418 {
 419 #ifdef __i386__
 420   int           rtn = FALSE;
 421
 422   curr_frame = newframe;
 423
 424   if( curr_frame >= nframe )
 425     {
 426       curr_frame = nframe - 1;
 427     }
 428
 429   if( curr_frame < 0 )
 430     {
 431       curr_frame = 0;
 432     }
 433
 434    if( frames && frames[curr_frame].frame.list.sourcefile != NULL )
 435     {
 436       DEBUG_List(&frames[curr_frame].frame.list, NULL, 0);
 437     }
 438
 439   rtn = TRUE;
 440   return (rtn);
 441 #else /* __i386__ */
 442   return FALSE;
 443 #endif /* __i386__ */
 444 }
 445
 446 int
 447 DEBUG_GetCurrentFrame(struct name_hash ** name, unsigned int * eip,
 448                       unsigned int * ebp)
 449 {
 450 #ifdef __i386__
 451   /*
 452    * If we don't have a valid backtrace, then just return.
 453    */
 454   if( frames == NULL )
 455     {
 456       return FALSE;
 457     }
 458
 459   /*
 460    * If we don't know what the current function is, then we also have
 461    * nothing to report here.
 462    */
 463   if( frames[curr_frame].frame.sym == NULL )
 464     {
 465       return FALSE;
 466     }
 467
 468   *name = frames[curr_frame].frame.sym;
 469   *eip = frames[curr_frame].eip;
 470   *ebp = frames[curr_frame].ebp;
 471
 472   return TRUE;
 473 #else /* __i386__ */
 474   return FALSE;
 475 #endif /* __i386__ */
 476 }
 477