gecko-dev/ipc/glue/SharedMemoryBasic_chromium.h
Jed Davis 91efa87e62 Bug 1440199 - Part 2: Remove named mode from IPC shared memory. r=froydnj
We're not using named shared memory, and supporting only anonymous
shared memory allows using other backends that are more compatible
with preventing a process from accessing any shared memory it wasn't
explicitly granted (i.e., sandboxing).

Specifically: SharedMemory::Open is removed; SharedMemory::Create no
longer takes a name, no longer has the open_existing option which doesn't
apply to anonymous memory, and no longer supports read-only memory
(anonymous memory which can never have been written isn't very useful).

This patch also fixes some comments in what remains of SharedMemory::Create.

MozReview-Commit-ID: 4kBrURtxq20

--HG--
extra : rebase_source : f6b1fb2fc79b6e9cdd251b3d9041036c0be503f9
2018-02-20 13:07:32 -07:00

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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_ipc_SharedMemoryBasic_chromium_h
#define mozilla_ipc_SharedMemoryBasic_chromium_h
#include "base/shared_memory.h"
#include "SharedMemory.h"
#ifdef FUZZING
#include "SharedMemoryFuzzer.h"
#endif
#include "nsDebug.h"
//
// This is a low-level wrapper around platform shared memory. Don't
// use it directly; use Shmem allocated through IPDL interfaces.
//
namespace mozilla {
namespace ipc {
class SharedMemoryBasic final : public SharedMemoryCommon<base::SharedMemoryHandle>
{
public:
SharedMemoryBasic()
{
}
virtual bool SetHandle(const Handle& aHandle, OpenRights aRights) override {
return mSharedMemory.SetHandle(aHandle, aRights == RightsReadOnly);
}
virtual bool Create(size_t aNbytes) override
{
bool ok = mSharedMemory.Create(aNbytes);
if (ok) {
Created(aNbytes);
}
return ok;
}
virtual bool Map(size_t nBytes) override
{
bool ok = mSharedMemory.Map(nBytes);
if (ok) {
Mapped(nBytes);
}
return ok;
}
virtual void CloseHandle() override
{
mSharedMemory.Close(false);
}
virtual void* memory() const override
{
#ifdef FUZZING
return SharedMemoryFuzzer::MutateSharedMemory(mSharedMemory.memory(),
mAllocSize);
#else
return mSharedMemory.memory();
#endif
}
virtual SharedMemoryType Type() const override
{
return TYPE_BASIC;
}
static Handle NULLHandle()
{
return base::SharedMemory::NULLHandle();
}
virtual bool IsHandleValid(const Handle &aHandle) const override
{
return base::SharedMemory::IsHandleValid(aHandle);
}
virtual bool ShareToProcess(base::ProcessId aProcessId,
Handle* new_handle) override
{
base::SharedMemoryHandle handle;
bool ret = mSharedMemory.ShareToProcess(aProcessId, &handle);
if (ret)
*new_handle = handle;
return ret;
}
private:
~SharedMemoryBasic()
{
}
base::SharedMemory mSharedMemory;
};
} // namespace ipc
} // namespace mozilla
#endif // ifndef mozilla_ipc_SharedMemoryBasic_chromium_h