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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "CacheNtDllThunk.h"
#include "mozilla/Maybe.h"
#include "mozilla/Span.h"
#include "mozilla/StaticPtr.h"
namespace mozilla {
static StaticAutoPtr<Buffer<IMAGE_THUNK_DATA>> sCachedNtDllThunk;
// This static method initializes sCachedNtDllThunk. Because it's called in
// XREMain::XRE_main, which happens long before WindowsProcessLauncher's ctor
// accesses sCachedNtDllThunk, there is no race on sCachedNtDllThunk, thus
// no mutex is needed.
static void CacheNtDllThunk() {
if (sCachedNtDllThunk) {
return;
}
do {
nt::PEHeaders ourExeImage(::GetModuleHandleW(nullptr));
if (!ourExeImage) {
break;
}
nt::PEHeaders ntdllImage(::GetModuleHandleW(L"ntdll.dll"));
if (!ntdllImage) {
break;
}
Maybe<Range<const uint8_t>> ntdllBoundaries = ntdllImage.GetBounds();
if (!ntdllBoundaries) {
break;
}
Maybe<Span<IMAGE_THUNK_DATA>> maybeNtDllThunks =
ourExeImage.GetIATThunksForModule("ntdll.dll", ntdllBoundaries.ptr());
if (maybeNtDllThunks.isNothing()) {
break;
}
sCachedNtDllThunk = new Buffer<IMAGE_THUNK_DATA>(maybeNtDllThunks.value());
return;
} while (false);
// Failed to cache IAT. Initializing the variable with nullptr.
sCachedNtDllThunk = new Buffer<IMAGE_THUNK_DATA>();
}
static Buffer<IMAGE_THUNK_DATA>* GetCachedNtDllThunk() {
return sCachedNtDllThunk;
}
} // namespace mozilla