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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_PTR_H_
#define SANDBOXED_API_VAR_PTR_H_
#include <algorithm>
#include <cstring>
#include <memory>
#include <string>
#include "absl/base/macros.h"
#include "absl/strings/str_format.h"
#include "sandboxed_api/var_abstract.h"
#include "sandboxed_api/var_reg.h"
namespace sapi::v {
// Class representing a pointer. Takes both Var* and regular pointers in the
// initializers.
class Ptr : public Reg<Var*> {
public:
Ptr() = delete;
explicit Ptr(Var* value, SyncType sync_type) : sync_type_(sync_type) {
Reg<Var*>::SetValue(value);
}
Var* GetPointedVar() const { return Reg<Var*>::GetValue(); }
void SetValue(Var* ptr) final { value_->SetRemote(ptr); }
Var* GetValue() const final {
return reinterpret_cast<Var*>(value_->GetRemote());
}
const void* GetDataPtr() final {
remote_ptr_cache_ = GetValue();
return &remote_ptr_cache_;
}
void SetDataFromPtr(const void* ptr, size_t max_sz) final {
void* tmp;
memcpy(&tmp, ptr, std::min(sizeof(tmp), max_sz));
SetValue(reinterpret_cast<Var*>(tmp));
}
// Getter/Setter for the sync_type_ field.
SyncType GetSyncType() { return sync_type_; }
void SetSyncType(SyncType sync_type) { sync_type_ = sync_type; }
std::string ToString() const final {
Var* var = GetPointedVar();
return absl::StrFormat(
"Ptr to obj:%p (type:'%s' val:'%s'), local:%p, remote:%p, size:%tx",
var, var->GetTypeString(), var->ToString(), var->GetLocal(),
var->GetRemote(), var->GetSize());
}
private:
// GetDataPtr() interface requires of us to return a pointer to the data
// (variable) that can be copied. We cannot get pointer to pointer with
// Var::GetRemote(), hence we cache it, and return pointer to it.
void* remote_ptr_cache_;
// Shall we synchronize the underlying object before/after call.
SyncType sync_type_;
};
// Good, old nullptr
class NullPtr : public Ptr {
public:
NullPtr() : Ptr(&void_obj_, SyncType::kSyncNone) {}
private:
Reg<void*> void_obj_;
};
// Pointer, which can only point to remote memory, and is never synchronized.
class RemotePtr : public Ptr {
public:
explicit RemotePtr(void* remote_addr)
: Ptr(&pointed_obj_, SyncType::kSyncNone) {
pointed_obj_.SetRemote(remote_addr);
}
private:
Reg<void*> pointed_obj_;
};
} // namespace sapi::v
#endif // SANDBOXED_API_VAR_PTR_H_
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