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// Copyright 2018 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "starboard/memory.h"
#include <windows.h>
bool SbMemoryProtect(void* virtual_address, int64_t size_bytes, int flags) {
ULONG new_protection = 0;
switch (flags) {
case kSbMemoryMapProtectReserved:
// After this call, the address will be in reserved state.
return VirtualFree(virtual_address, size_bytes, MEM_DECOMMIT);
case kSbMemoryMapProtectRead:
new_protection = PAGE_READONLY;
break;
// Windows does not provide write only mode privileges
// are escalated to read/write.
case kSbMemoryMapProtectWrite:
case kSbMemoryMapProtectReadWrite:
new_protection = PAGE_READWRITE;
break;
#if SB_CAN(MAP_EXECUTABLE_MEMORY)
case kSbMemoryMapProtectExec:
new_protection = PAGE_EXECUTE;
break;
case kSbMemoryMapProtectRead | kSbMemoryMapProtectExec:
new_protection = PAGE_EXECUTE_READ;
break;
#endif
// No other protections are supported, see
// https://msdn.microsoft.com/en-us/library/windows/desktop/mt169846.
default:
return false;
}
ULONG old_protection;
// Changing protection from No-Access to others needs the memory to be
// committed first. Commit committed pages will not reset them to zero.
VirtualAllocFromApp(virtual_address, size_bytes, MEM_COMMIT, PAGE_READONLY);
return VirtualProtectFromApp(virtual_address, size_bytes, new_protection,
&old_protection) != 0;
}