Tidyed up stack backtrace code a bit, and added a simple special
case for backtracing from a null EIP.
diff --git a/debugger/stack.c b/debugger/stack.c
index 8e4c99f..1eb45ac 100644
--- a/debugger/stack.c
+++ b/debugger/stack.c
@@ -79,7 +79,7 @@
}
#ifdef __i386__
-static void DEBUG_ForceFrame(DBG_ADDR *stack, DBG_ADDR *code, int frameno, int bits, int noisy)
+static void DEBUG_ForceFrame(DBG_ADDR *stack, DBG_ADDR *code, int frameno, int bits, int noisy, const char *caveat)
{
int theframe = nframe++;
frames = (struct bt_info *)DBG_realloc(frames,
@@ -99,16 +99,16 @@
frames[theframe].ss = stack->seg;
frames[theframe].ebp = stack->off;
if (noisy) {
- DEBUG_Printf( DBG_CHN_MESG, (bits == 16) ? " (bp=%04lx)\n" : " (ebp=%08lx)\n", stack->off );
+ DEBUG_Printf( DBG_CHN_MESG, (bits == 16) ? " (bp=%04lx%s)\n" : " (ebp=%08lx%s)\n", stack->off, caveat?caveat:"" );
}
}
static BOOL DEBUG_Frame16(DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
{
- unsigned int ss = addr->seg, possible_cs = 0;
+ unsigned int possible_cs = 0;
FRAME16 frame;
- int theframe = nframe;
void* p = (void*)DEBUG_ToLinear(addr);
+ DBG_ADDR code;
if (!p) return FALSE;
@@ -117,12 +117,7 @@
return FALSE;
}
if (!frame.bp) return FALSE;
- nframe++;
- frames = (struct bt_info *)DBG_realloc(frames,
- nframe*sizeof(struct bt_info));
- if (noisy)
- DEBUG_Printf(DBG_CHN_MESG,"%s%d ", (theframe == curr_frame ? "=>" : " "),
- frameno);
+
if (frame.bp & 1) *cs = frame.cs;
else {
/* not explicitly marked as far call,
@@ -138,33 +133,19 @@
}
}
}
- frames[theframe].cs = addr->seg = *cs;
- frames[theframe].eip = addr->off = frame.ip;
- if (noisy)
- frames[theframe].frame = DEBUG_PrintAddressAndArgs( addr, 16,
- frame.bp, TRUE );
- else
- DEBUG_FindNearestSymbol( addr, TRUE,
- &frames[theframe].frame.sym, frame.bp,
- &frames[theframe].frame.list);
- frames[theframe].ss = addr->seg = ss;
- frames[theframe].ebp = addr->off = frame.bp & ~1;
- if (noisy) {
- DEBUG_Printf( DBG_CHN_MESG, " (bp=%04lx", addr->off );
- if (possible_cs) {
- DEBUG_Printf( DBG_CHN_MESG, ", far call assumed" );
- }
- DEBUG_Printf( DBG_CHN_MESG, ")\n" );
- }
+ code.seg = *cs;
+ code.off = frame.ip;
+ addr->off = frame.bp & ~1;
+ DEBUG_ForceFrame(addr, &code, frameno, 16, noisy, possible_cs ? ", far call assumed" : NULL );
return TRUE;
}
static BOOL DEBUG_Frame32(DBG_ADDR *addr, unsigned int *cs, int frameno, int noisy)
{
- unsigned int ss = addr->seg;
FRAME32 frame;
- int theframe = nframe;
void* p = (void*)DEBUG_ToLinear(addr);
+ DBG_ADDR code;
+ DWORD old_bp = addr->off;
if (!p) return FALSE;
@@ -173,27 +154,12 @@
return FALSE;
}
if (!frame.ip) return FALSE;
-
- nframe++;
- frames = (struct bt_info *)DBG_realloc(frames,
- nframe*sizeof(struct bt_info));
- if (noisy)
- DEBUG_Printf(DBG_CHN_MESG,"%s%d ", (theframe == curr_frame ? "=>" : " "),
- frameno);
- frames[theframe].cs = addr->seg = *cs;
- frames[theframe].eip = addr->off = frame.ip;
- if (noisy)
- frames[theframe].frame = DEBUG_PrintAddressAndArgs( addr, 32,
- frame.bp, TRUE );
- else
- DEBUG_FindNearestSymbol( addr, TRUE,
- &frames[theframe].frame.sym, frame.bp,
- &frames[theframe].frame.list);
- if (noisy) DEBUG_Printf( DBG_CHN_MESG, " (ebp=%08lx)\n", frame.bp );
- frames[theframe].ss = addr->seg = ss;
- frames[theframe].ebp = frame.bp;
- if (addr->off == frame.bp) return FALSE;
+
+ code.seg = *cs;
+ code.off = frame.ip;
addr->off = frame.bp;
+ DEBUG_ForceFrame(addr, &code, frameno, 32, noisy, NULL);
+ if (addr->off == old_bp) return FALSE;
return TRUE;
}
#endif
@@ -218,11 +184,10 @@
if (noisy) DEBUG_Printf( DBG_CHN_MESG, "Backtrace:\n" );
- nframe = 1;
+ nframe = 0;
if (frames) DBG_free( frames );
- frames = (struct bt_info *) DBG_alloc( sizeof(struct bt_info) );
- if (noisy)
- DEBUG_Printf(DBG_CHN_MESG,"%s%d ",(curr_frame == 0 ? "=>" : " "), frameno);
+ /* frames = (struct bt_info *) DBG_alloc( sizeof(struct bt_info) ); */
+ frames = NULL;
if (DEBUG_IsSelectorSystem(ss)) ss = 0;
if (DEBUG_IsSelectorSystem(cs)) cs = 0;
@@ -231,29 +196,29 @@
switch (DEBUG_GetSelectorType(ss))
{
case 32:
- frames[0].cs = addr.seg = cs;
- frames[0].eip = addr.off = DEBUG_context.Eip;
- if (noisy)
- frames[0].frame = DEBUG_PrintAddress( &addr, 32, TRUE );
- else
- DEBUG_FindNearestSymbol( &addr, TRUE, &frames[0].frame.sym, 0,
- &frames[0].frame.list);
- frames[0].ss = addr.seg = ss;
- frames[0].ebp = addr.off = DEBUG_context.Ebp;
- if (noisy) DEBUG_Printf( DBG_CHN_MESG, " (ebp=%08x)\n", frames[0].ebp );
+ code.seg = cs;
+ code.off = DEBUG_context.Eip;
+ addr.seg = ss;
+ addr.off = DEBUG_context.Ebp;
+ DEBUG_ForceFrame( &addr, &code, frameno, 32, noisy, NULL );
+ if (!(code.seg || code.off)) {
+ /* trying to execute a null pointer... yuck...
+ * if it was a call to null, the return EIP should be
+ * available at SS:ESP, so let's try to retrieve it */
+ tmp.seg = ss;
+ tmp.off = DEBUG_context.Esp;
+ if (DEBUG_READ_MEM(DEBUG_ToLinear(&tmp), &code.off, sizeof(code.off))) {
+ DEBUG_ForceFrame( &addr, &code, ++frameno, 32, noisy, ", null call assumed" );
+ }
+ }
is16 = FALSE;
break;
case 16:
- frames[0].cs = addr.seg = cs;
- frames[0].eip = addr.off = LOWORD(DEBUG_context.Eip);
- if (noisy)
- frames[0].frame = DEBUG_PrintAddress( &addr, 16, TRUE );
- else
- DEBUG_FindNearestSymbol( &addr, TRUE, &frames[0].frame.sym, 0,
- &frames[0].frame.list);
- frames[0].ss = addr.seg = ss;
- frames[0].ebp = addr.off = LOWORD(DEBUG_context.Ebp);
- if (noisy) DEBUG_Printf( DBG_CHN_MESG, " (bp=%04x)\n", frames[0].ebp );
+ code.seg = cs;
+ code.off = LOWORD(DEBUG_context.Eip);
+ addr.seg = ss;
+ addr.off = LOWORD(DEBUG_context.Ebp);
+ DEBUG_ForceFrame( &addr, &code, frameno, 16, noisy, NULL );
is16 = TRUE;
break;
default:
@@ -317,7 +282,7 @@
cs = 0;
addr.seg = 0;
addr.off = frame32.ebp;
- DEBUG_ForceFrame( &addr, &code, ++frameno, 32, noisy );
+ DEBUG_ForceFrame( &addr, &code, ++frameno, 32, noisy, NULL );
next_switch = cur_switch;
tmp.seg = SELECTOROF(next_switch);
@@ -351,7 +316,7 @@
cs = frame16.cs;
addr.seg = SELECTOROF(next_switch);
addr.off = frame16.bp;
- DEBUG_ForceFrame( &addr, &code, ++frameno, 16, noisy );
+ DEBUG_ForceFrame( &addr, &code, ++frameno, 16, noisy, NULL );
next_switch = cur_switch;
if (!DEBUG_READ_MEM((void*)next_switch, &frame32, sizeof(STACK32FRAME))) {
