abe7f841ca
Backed out changeset 3e8d2c47138c (bug 1454816) Backed out changeset 80ff20241831 (bug 1454816) Backed out changeset 28c2d6d2a683 (bug 1454816) Backed out changeset 236943ab4142 (bug 1454816)
135 lines
3.6 KiB
C++
135 lines
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/ipc/SharedMemory.h"
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#include "mozilla/Atomics.h"
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#include "nsIMemoryReporter.h"
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#ifdef FUZZING
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# include "mozilla/ipc/SharedMemoryFuzzer.h"
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#endif
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namespace mozilla::ipc {
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static Atomic<size_t> gShmemAllocated;
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static Atomic<size_t> gShmemMapped;
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class ShmemReporter final : public nsIMemoryReporter {
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~ShmemReporter() = default;
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public:
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NS_DECL_THREADSAFE_ISUPPORTS
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NS_IMETHOD
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CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData,
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bool aAnonymize) override {
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MOZ_COLLECT_REPORT(
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"shmem-allocated", KIND_OTHER, UNITS_BYTES, gShmemAllocated,
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"Memory shared with other processes that is accessible (but not "
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"necessarily mapped).");
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MOZ_COLLECT_REPORT(
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"shmem-mapped", KIND_OTHER, UNITS_BYTES, gShmemMapped,
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"Memory shared with other processes that is mapped into the address "
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"space.");
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return NS_OK;
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}
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};
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NS_IMPL_ISUPPORTS(ShmemReporter, nsIMemoryReporter)
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SharedMemory::SharedMemory() : mAllocSize(0), mMappedSize(0) {
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static Atomic<bool> registered;
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if (registered.compareExchange(false, true)) {
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RegisterStrongMemoryReporter(new ShmemReporter());
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}
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}
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SharedMemory::~SharedMemory() {
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Unmap();
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CloseHandle();
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MOZ_ASSERT(gShmemAllocated >= mAllocSize,
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"Can't destroy more than allocated");
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gShmemAllocated -= mAllocSize;
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mAllocSize = 0;
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}
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bool SharedMemory::WriteHandle(IPC::MessageWriter* aWriter) {
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Handle handle = CloneHandle();
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if (!handle) {
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return false;
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}
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IPC::WriteParam(aWriter, std::move(handle));
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return true;
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}
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bool SharedMemory::ReadHandle(IPC::MessageReader* aReader) {
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Handle handle;
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return IPC::ReadParam(aReader, &handle) && IsHandleValid(handle) &&
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SetHandle(std::move(handle), RightsReadWrite);
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}
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void SharedMemory::Protect(char* aAddr, size_t aSize, int aRights) {
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char* memStart = reinterpret_cast<char*>(Memory());
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if (!memStart) MOZ_CRASH("SharedMemory region points at NULL!");
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char* memEnd = memStart + Size();
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char* protStart = aAddr;
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if (!protStart) MOZ_CRASH("trying to Protect() a NULL region!");
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char* protEnd = protStart + aSize;
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if (!(memStart <= protStart && protEnd <= memEnd)) {
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MOZ_CRASH("attempt to Protect() a region outside this SharedMemory");
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}
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// checks alignment etc.
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SystemProtect(aAddr, aSize, aRights);
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}
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size_t SharedMemory::PageAlignedSize(size_t aSize) {
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size_t pageSize = SystemPageSize();
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size_t nPagesNeeded = size_t(ceil(double(aSize) / double(pageSize)));
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return pageSize * nPagesNeeded;
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}
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bool SharedMemory::Create(size_t aNBytes) {
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bool ok = CreateImpl(aNBytes);
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if (ok) {
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mAllocSize = aNBytes;
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gShmemAllocated += mAllocSize;
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}
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return ok;
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}
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bool SharedMemory::Map(size_t aNBytes, void* fixedAddress) {
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bool ok = MapImpl(aNBytes, fixedAddress);
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if (ok) {
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mMappedSize = aNBytes;
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gShmemMapped += mMappedSize;
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}
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return ok;
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}
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void SharedMemory::Unmap() {
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MOZ_ASSERT(gShmemMapped >= mMappedSize, "Can't unmap more than mapped");
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UnmapImpl(mMappedSize);
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gShmemMapped -= mMappedSize;
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mMappedSize = 0;
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}
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void* SharedMemory::Memory() const {
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#ifdef FUZZING
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return SharedMemoryFuzzer::MutateSharedMemory(MemoryImpl(), mAllocSize);
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#else
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return MemoryImpl();
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#endif
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}
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} // namespace mozilla::ipc
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