From 51f6aeb462ba645c3978773a91a106d76b5d3344 Mon Sep 17 00:00:00 2001
From: Alexandre Julliard <julliard@winehq.org>
Date: Thu, 13 Apr 2000 17:21:36 +0000
Subject: [PATCH] Implemented guard pages and stack overflow exceptions.

---
 dlls/ntdll/signal_i386.c |  5 +++--
 include/global.h         |  2 +-
 memory/virtual.c         | 28 ++++++++++++++++++++++++----
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/dlls/ntdll/signal_i386.c b/dlls/ntdll/signal_i386.c
index 02a932b0a96..e964f8f00bb 100644
--- a/dlls/ntdll/signal_i386.c
+++ b/dlls/ntdll/signal_i386.c
@@ -475,13 +475,14 @@ static HANDLER_DEF(segv_handler)
 {
     EXCEPTION_RECORD rec;
     CONTEXT context;
+    DWORD page_fault_code = EXCEPTION_ACCESS_VIOLATION;
 
     handler_init( &context, HANDLER_CONTEXT );
 
 #ifdef CR2_sig
     /* we want the page-fault case to be fast */
     if (get_trap_code(HANDLER_CONTEXT) == T_PAGEFLT)
-        if (VIRTUAL_HandleFault( (LPVOID)CR2_sig(HANDLER_CONTEXT) )) return;
+        if (!(page_fault_code = VIRTUAL_HandleFault( (LPVOID)CR2_sig(HANDLER_CONTEXT) ))) return;
 #endif
 
     save_context( &context, HANDLER_CONTEXT );
@@ -520,7 +521,7 @@ static HANDLER_DEF(segv_handler)
 #endif /* ERROR_sig */
         rec.ExceptionInformation[1] = CR2_sig(HANDLER_CONTEXT);
 #endif /* CR2_sig */
-        rec.ExceptionCode = EXCEPTION_ACCESS_VIOLATION;
+        rec.ExceptionCode = page_fault_code;
         break;
     case T_ALIGNFLT:  /* Alignment check exception */
         /* FIXME: pass through exception handler first? */
diff --git a/include/global.h b/include/global.h
index aa93047cb9e..65897108474 100644
--- a/include/global.h
+++ b/include/global.h
@@ -37,7 +37,7 @@ extern LPVOID VIRTUAL_MapFileW( LPCWSTR name );
 
 typedef BOOL (*HANDLERPROC)(LPVOID, LPCVOID);
 extern BOOL VIRTUAL_SetFaultHandler(LPCVOID addr, HANDLERPROC proc, LPVOID arg);
-extern BOOL VIRTUAL_HandleFault(LPCVOID addr);
+extern DWORD VIRTUAL_HandleFault(LPCVOID addr);
 
 /* memory/atom.c */
 extern BOOL ATOM_Init( WORD globalTableSel );
diff --git a/memory/virtual.c b/memory/virtual.c
index 21dd40faee3..f23bc3f7be5 100644
--- a/memory/virtual.c
+++ b/memory/virtual.c
@@ -510,13 +510,33 @@ BOOL VIRTUAL_SetFaultHandler( LPCVOID addr, HANDLERPROC proc, LPVOID arg )
 /***********************************************************************
  *           VIRTUAL_HandleFault
  */
-BOOL VIRTUAL_HandleFault( LPCVOID addr )
+DWORD VIRTUAL_HandleFault( LPCVOID addr )
 {
     FILE_VIEW *view = VIRTUAL_FindView((UINT)addr);
+    DWORD ret = EXCEPTION_ACCESS_VIOLATION;
 
-    if (view && view->handlerProc)
-        return view->handlerProc(view->handlerArg, addr);
-    return FALSE;
+    if (view)
+    {
+        if (view->handlerProc)
+        {
+            if (view->handlerProc(view->handlerArg, addr)) ret = 0;  /* handled */
+        }
+        else
+        {
+            BYTE vprot = view->prot[((UINT)addr - view->base) >> page_shift];
+            UINT page = (UINT)addr & ~page_mask;
+            char *stack = (char *)NtCurrentTeb()->stack_base + SIGNAL_STACK_SIZE + page_mask + 1;
+            if (vprot & VPROT_GUARD)
+            {
+                VIRTUAL_SetProt( view, page, page_mask + 1, vprot & ~VPROT_GUARD );
+                ret = STATUS_GUARD_PAGE_VIOLATION;
+            }
+            /* is it inside the stack guard pages? */
+            if (((char *)addr >= stack) && ((char *)addr < stack + 2*(page_mask+1)))
+                ret = STATUS_STACK_OVERFLOW;
+        }
+    }
+    return ret;
 }