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/* protw3.c: PROTECTION FOR WIN32
*
* $Id$
* Copyright (c) 2001-2020 Ravenbrook Limited. See end of file for license.
*/
#include "prmcw3.h"
#if !defined(MPS_OS_W3)
#error "protw3.c is specific to MPS_OS_W3"
#endif
#include "mpswin.h"
#include "vm.h" /* PageSize */
SRCID(protw3, "$Id$");
void ProtSet(Addr base, Addr limit, AccessSet mode)
{
DWORD newProtect;
DWORD oldProtect;
AVER(base < limit);
AVER(base != 0);
AVERT(AccessSet, mode);
newProtect = PAGE_EXECUTE_READWRITE;
if((mode & AccessWRITE) != 0)
newProtect = PAGE_EXECUTE_READ;
if((mode & AccessREAD) != 0)
newProtect = PAGE_NOACCESS;
if(VirtualProtect((LPVOID)base, (SIZE_T)AddrOffset(base, limit),
newProtect, &oldProtect) == 0)
NOTREACHED;
}
LONG WINAPI ProtSEHfilter(LPEXCEPTION_POINTERS info)
{
LPEXCEPTION_RECORD er;
ULONG_PTR address;
AccessSet mode;
Addr base, limit;
LONG action;
DWORD lastError;
MutatorContextStruct context;
er = info->ExceptionRecord;
if(er->ExceptionCode != EXCEPTION_ACCESS_VIOLATION)
return EXCEPTION_CONTINUE_SEARCH;
/* This is the first point where we call a Windows API function that
* might change the last error. There are also no early returns from
* this point onwards.
*/
lastError = GetLastError();
MutatorContextInitFault(&context, info);
/* assert that the exception is continuable */
/* Note that Microsoft say that this field should be 0 or */
/* EXCEPTION_NONCONTINUABLE, but this is not true */
AVER((er->ExceptionFlags & EXCEPTION_NONCONTINUABLE) == 0);
/* er->ExceptionRecord is pointer to next exception in chain */
/* er->ExceptionAddress is where exception occurred */
AVER(er->NumberParameters >= 2);
switch (er->ExceptionInformation[0]) {
case 0: /* read */
case 8: /* execute */
mode = AccessREAD;
break;
case 1: /* write */
/* Pages cannot be made write-only, so an attempt to write must
also cause a read-access if necessary */
mode = AccessREAD | AccessWRITE;
break;
default:
/* <https://docs.microsoft.com/en-gb/windows/desktop/api/winnt/ns-winnt-_exception_record> */
NOTREACHED;
mode = AccessREAD | AccessWRITE;
break;
}
address = er->ExceptionInformation[1];
base = (Addr)address;
limit = AddrAdd(address, sizeof(Addr));
if(base < limit) {
if(ArenaAccess(base, mode, &context))
action = EXCEPTION_CONTINUE_EXECUTION;
else
action = EXCEPTION_CONTINUE_SEARCH;
} else {
/* Access on last sizeof(Addr) (ie 4 on this platform) bytes */
/* in memory. We assume we can't get this page anyway */
/* <code/vmw3.c#assume.not-last> so it can't be our fault. */
action = EXCEPTION_CONTINUE_SEARCH;
}
/* Restore the last error value before returning. */
SetLastError(lastError);
return action;
}
/* ProtSetup -- set up the protection system */
void ProtSetup(void)
{
void *handler;
/* See "AddVectoredExceptionHandler function (Windows)"
<https://msdn.microsoft.com/en-us/library/windows/desktop/ms679274%28v=vs.85%29.aspx> */
/* ProtSetup is called only once per process, not once per arena, so
this exception handler is only installed once. */
handler = AddVectoredExceptionHandler(1uL, ProtSEHfilter);
AVER(handler != NULL);
}
/* ProtGranularity -- return the granularity of protection */
Size ProtGranularity(void)
{
/* Individual pages can be protected. */
return PageSize();
}
/* ProtSync -- synchronize protection settings with hardware
*
* This does nothing under Win32. See protan.c.
*/
void ProtSync(Arena arena)
{
UNUSED(arena);
NOOP;
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2020 Ravenbrook Limited <https://www.ravenbrook.com/>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
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