184 lines
6.2 KiB
C++
184 lines
6.2 KiB
C++
/***
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*dbgstk.c - debug check stack routine
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*
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* Copyright (c) 1986-1995, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* This module contains a debug impelmentation of the standard _chkstk
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* for i386. It will do the standard stack probe (code copied from
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* VC5 CRT) and then call a debug routine which will have the oportunity
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* top spew the stack before it gets initialized (or not).
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*
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*******************************************************************************/
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#include "headers.hxx"
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#if defined(USE_STACK_SPEW) && defined(_X86_)
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#pragma check_stack(off)
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static BOOL g_fStackSpewEnabled = FALSE;
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static DWORD g_dwSpew = 0x0;
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extern "C" void __declspec(naked) __cdecl _chkstk()
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{
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_asm
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{
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; First probe the stack. We do this because
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; we don't want to write past the stack guard page
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; Note that this code came from the original
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; c run time source.
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push ecx ; save ecx
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push eax ; save eax (size of stack needed)
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cmp eax,1000h ; more than one page requested?
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lea ecx,[esp] + 12 ; compute new stack pointer in ecx
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; correct for return address and
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; saved ecx, eax
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jb short lastpage ; no
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probepages:
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sub ecx,1000h ; yes, move down a page
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sub eax,1000h ; adjust request and...
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test dword ptr [ecx],eax ; ...probe it
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cmp eax,1000h ; more than one page requested?
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jae short probepages ; no
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lastpage:
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sub ecx,eax ; move stack down by eax
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mov eax,esp ; save current tos and do a...
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test dword ptr [ecx],eax ; ...probe in case a page was crossed
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; Now set up and write our data into the area of the stack
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; that was opened up
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lea esp,[ecx] - 12 ; set the stack pointer to the bottom
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; leave room 12 in padding so we don't
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; clobber ourselves
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mov ecx,dword ptr [eax+8] ; recover return address
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push ecx
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cmp g_fStackSpewEnabled,0 ; see if we are enabled
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mov ecx,dword ptr [eax+4] ; recover original ecx
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je done ; not enabled
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push ecx ; save original ecx
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pushfd ; save flags
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std ; set DI: decr edi after stosd
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mov ecx,dword ptr [eax] ; recover original eax (stack size)
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push edi ; save edi on stack also
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lea edi,[eax]+8 ; load up iterator start address
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shr ecx,2 ; get count of dwords
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mov eax,g_dwSpew ; load up value
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rep stosd ; let 'er rip
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pop edi ; pop saved edi
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popfd ; pop flags
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pop ecx ; pop saved ecx
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done:
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ret 12 ; return, popping off 12 padding
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}
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}
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// NOTE: _alloca_probe is impelemented exactly the same as _chkstk
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// I'd like to find some way to merge these two pieces of code but I
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// don't know how with inline assembly...
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extern "C" void __declspec(naked) __cdecl _alloca_probe()
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{
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_asm
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{
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; First probe the stack. We do this because
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; we don't want to write past the stack guard page
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; Note that this code came from the original
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; c run time source.
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push ecx ; save ecx
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push eax ; save eax (size of stack needed)
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cmp eax,1000h ; more than one page requested?
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lea ecx,[esp] + 12 ; compute new stack pointer in ecx
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; correct for return address and
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; saved ecx, eax
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jb short lastpage ; no
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probepages:
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sub ecx,1000h ; yes, move down a page
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sub eax,1000h ; adjust request and...
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test dword ptr [ecx],eax ; ...probe it
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cmp eax,1000h ; more than one page requested?
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jae short probepages ; no
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lastpage:
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sub ecx,eax ; move stack down by eax
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mov eax,esp ; save current tos and do a...
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test dword ptr [ecx],eax ; ...probe in case a page was crossed
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; Now set up and write our data into the area of the stack
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; that was opened up
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lea esp,[ecx] - 12 ; set the stack pointer to the bottom
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; leave room 12 in padding so we don't
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; clobber ourselves
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mov ecx,dword ptr [eax+8] ; recover return address
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push ecx
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cmp g_fStackSpewEnabled,0 ; see if we are enabled
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mov ecx,dword ptr [eax+4] ; recover original ecx
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je done ; not enabled
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push ecx ; save original ecx
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pushfd ; save flags
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std ; set DI: decr edi after stosd
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mov ecx,dword ptr [eax] ; recover original eax (stack size)
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push edi ; save edi on stack also
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lea edi,[eax]+8 ; load up iterator start address
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shr ecx,2 ; get count of dwords
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mov eax,g_dwSpew ; load up value
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rep stosd ; let 'er rip
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pop edi ; pop saved edi
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popfd ; pop flags
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pop ecx ; pop saved ecx
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done:
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ret 12 ; return, popping off 12 padding
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}
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}
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//
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// Initialize the debug stack system
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//
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extern "C" void
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InitChkStk(BOOL dwFill)
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{
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g_dwSpew = dwFill;
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g_fStackSpewEnabled = TRUE;
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}
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#endif
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