sandboxed-api/sandboxed_api/var_abstract.h

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// Copyright 2019 Google LLC
//
// 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
//
// https://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.
#ifndef SANDBOXED_API_VAR_ABSTRACT_H_
#define SANDBOXED_API_VAR_ABSTRACT_H_
#include <ctime>
#include <memory>
#include <string>
#include <type_traits>
#include "absl/base/attributes.h"
#include "absl/base/macros.h"
#include "absl/status/status.h"
#include "sandboxed_api/var_type.h"
namespace sandbox2 {
class Comms;
} // namespace sandbox2
namespace sapi {
class RPCChannel;
class Sandbox;
} // namespace sapi
namespace sapi::v {
class Ptr;
class ABSL_DEPRECATED(
"Use the Var::PtrXXX() family of methods instead") Pointable {
public:
enum SyncType {
// Do not synchronize the underlying object after/before calls.
kSyncNone = 0x0,
// Synchronize the underlying object (send the data to the sandboxee)
// before the call takes place.
kSyncBefore = 0x1,
// Synchronize the underlying object (retrieve data from the sandboxee)
// after the call has finished.
kSyncAfter = 0x2,
// Synchronize the underlying object with the remote object, by sending the
// data to the sandboxee before the call, and retrieving it from the
// sandboxee after the call has finished.
kSyncBoth = kSyncBefore | kSyncAfter,
};
virtual ~Pointable() = default;
};
// An abstract class representing variables.
class Var : public Pointable {
public:
Var(const Var&) = delete;
Var& operator=(const Var&) = delete;
virtual ~Var();
// Returns the address of the storage (remote side).
virtual void* GetRemote() const { return remote_; }
// Sets the address of the remote storage.
virtual void SetRemote(void* remote) { remote_ = remote; }
// Returns the address of the storage (local side).
virtual void* GetLocal() const { return local_; }
// Returns the size of the local variable storage.
virtual size_t GetSize() const = 0;
// Returns the type of the variable.
virtual Type GetType() const = 0;
// Returns a string representation of the variable type.
virtual std::string GetTypeString() const = 0;
// Returns a string representation of the variable value.
virtual std::string ToString() const = 0;
// Functions to get pointers with certain type of synchronization schemes.
Ptr* PtrNone();
Ptr* PtrBoth();
Ptr* PtrBefore();
Ptr* PtrAfter();
protected:
Var() = default;
// Set pointer to local storage class.
void SetLocal(void* local) { local_ = local; }
// Setter/Getter for the address of a Comms object which can be used to
// remotely free allocated memory backing up this variable, upon this
// object's end of life-time
void SetFreeRPCChannel(RPCChannel* rpc_channel) {
free_rpc_channel_ = rpc_channel;
}
RPCChannel* GetFreeRPCChannel() { return free_rpc_channel_; }
// Allocates the local variable on the remote side. The 'automatic_free'
// argument dictates whether the remote memory should be freed upon end of
// this object's lifetime.
virtual absl::Status Allocate(RPCChannel* rpc_channel, bool automatic_free);
// Frees the local variable on the remote side.
virtual absl::Status Free(RPCChannel* rpc_channel);
// Transfers the variable to the sandboxee's address space, has to be
// allocated there first.
virtual absl::Status TransferToSandboxee(RPCChannel* rpc_channel, pid_t pid);
// Transfers the variable from the sandboxee's address space.
virtual absl::Status TransferFromSandboxee(RPCChannel* rpc_channel,
pid_t pid);
private:
// Needed so that we can use unique_ptr with incomplete type.
struct PtrDeleter {
void operator()(Ptr* p);
};
// Invokes Allocate()/Free()/Transfer*Sandboxee().
friend class ::sapi::Sandbox;
std::unique_ptr<Ptr, PtrDeleter> ptr_none_;
std::unique_ptr<Ptr, PtrDeleter> ptr_both_;
std::unique_ptr<Ptr, PtrDeleter> ptr_before_;
std::unique_ptr<Ptr, PtrDeleter> ptr_after_;
// Pointer to local storage of the variable.
void* local_ = nullptr;
// Pointer to remote storage of the variable.
void* remote_ = nullptr;
// Comms which can be used to free resources allocated in the sandboxer upon
// this process' end of lifetime.
RPCChannel* free_rpc_channel_ = nullptr;
};
} // namespace sapi::v
#endif // SANDBOXED_API_VAR_ABSTRACT_H_