Keep only base/extractor.[cc|h].

third_party/minicrt/resetstk.c

-/***
-*resetstk.c - Recover from Stack overflow.
-*
-*       Copyright (c) Microsoft Corporation. All rights reserved.
-*
-*Purpose:
-*       Defines the _resetstkoflw() function.
-*
-*******************************************************************************/
-
-#include <stdlib.h>
-#include <malloc.h>
-#include <windows.h>
-
-#define MIN_STACK_REQ_WIN9X 17
-#define MIN_STACK_REQ_WINNT 2
-
-#define _osplatform VER_PLATFORM_WIN32_NT
-
-/***
-* void _resetstkoflw() - Recovers from Stack Overflow
-*
-* Purpose:
-*       Sets the guard page to its position before the stack overflow.
-*
-* Exit:
-*       Returns nonzero on success, zero on failure
-*
-*******************************************************************************/
-
-int _resetstkoflw()
-{
-    LPBYTE pStack, pGuard, pStackBase, pMaxGuard, pMinGuard;
-    MEMORY_BASIC_INFORMATION mbi;
-    SYSTEM_INFO si;
-    DWORD PageSize;
-    DWORD flNewProtect;
-    DWORD flOldProtect;
-
-    // Use _alloca() to get the current stack pointer
-
-    pStack = _alloca(1);
-
-    // Find the base of the stack.
-
-    if (VirtualQuery(pStack, &mbi, sizeof mbi) == 0)
-        return 0;
-    pStackBase = mbi.AllocationBase;
-
-    // Find the page just below where the stack pointer currently points.
-    // This is the highest potential guard page.
-
-    GetSystemInfo(&si);
-    PageSize = si.dwPageSize;
-
-    pMaxGuard = (LPBYTE) (((DWORD_PTR)pStack & ~(DWORD_PTR)(PageSize - 1))
-                       - PageSize);
-
-    // If the potential guard page is too close to the start of the stack
-    // region, abandon the reset effort for lack of space.  Win9x has a
-    // larger reserved stack requirement.
-
-    pMinGuard = pStackBase + ((_osplatform == VER_PLATFORM_WIN32_WINDOWS)
-                              ? MIN_STACK_REQ_WIN9X
-                              : MIN_STACK_REQ_WINNT) * PageSize;
-
-    if (pMaxGuard < pMinGuard)
-        return 0;
-
-    // On a non-Win9x system, do nothing if a guard page is already present,
-    // else set up the guard page to the bottom of the committed range,
-    // allowing for the reserved stack requirement.
-    // For Win9x, just set guard page below the current stack page.
-
-    if (_osplatform != VER_PLATFORM_WIN32_WINDOWS) {
-
-        // Find first block of committed memory in the stack region
-
-        pGuard = pStackBase;
-        do {
-            if (VirtualQuery(pGuard, &mbi, sizeof mbi) == 0)
-                return 0;
-            pGuard = pGuard + mbi.RegionSize;
-        } while ((mbi.State & MEM_COMMIT) == 0);
-        pGuard = mbi.BaseAddress;
-
-        // If first committed block is already marked as a guard page,
-        // there is nothing that needs to be done, so return success.
-
-        if (mbi.Protect & PAGE_GUARD)
-            return 1;
-
-        // Fail if the first committed block is above the highest potential
-        // guard page.  Should never happen.
-
-        if (pMaxGuard < pGuard)
-            return 0;
-
-        // Make sure to leave enough room so the next overflow will have
-        // the proper reserved stack requirement available.
-
-        if (pGuard < pMinGuard)
-            pGuard = pMinGuard;
-
-        VirtualAlloc(pGuard, PageSize, MEM_COMMIT, PAGE_READWRITE);
-    }
-    else {
-        pGuard = pMaxGuard;
-    }
-
-    // Enable the new guard page.
-
-    flNewProtect = _osplatform == VER_PLATFORM_WIN32_WINDOWS
-                   ? PAGE_NOACCESS
-                   : PAGE_READWRITE | PAGE_GUARD;
-
-    return VirtualProtect(pGuard, PageSize, flNewProtect, &flOldProtect);
-}