tlbmc/io/ioctl.h

/*
 * Copyright 2020 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
 *
 *      http://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.
 */

// Provides a virtual interface for execution ioctl() operations.
//
// This doesn't provide any actual functionality, it simply acts as a trivial
// wrapper around the system call so that users of it can take it as an input to
// support dependency injection for testing.

#ifndef THIRD_PARTY_ECCLESIA_LIB_IO_IOCTL_H_
#define THIRD_PARTY_ECCLESIA_LIB_IO_IOCTL_H_

#include <cstdint>

namespace ecclesia {

class IoctlInterface {
 public:
  IoctlInterface() {}
  virtual ~IoctlInterface() = default;

  // Call ioctl with the given arguments. Note that while technically ioctl is
  // a variadic function, you can only actually provide a single variadic
  // parameter and so we support only void* (for pointer valued arguments) and
  // intptr_t (for scalar integer arguments).
  virtual int Call(int fd, unsigned long request, intptr_t argi) = 0;
  virtual int Call(int fd, unsigned long request, void *argp) = 0;
};

// Implementation of the interface that uses the system call.
class SysIoctl final : public IoctlInterface {
 public:
  int Call(int fd, unsigned long request, intptr_t argi) override;
  int Call(int fd, unsigned long request, void *argp) override;
};

}  // namespace ecclesia

#endif  // THIRD_PARTY_ECCLESIA_LIB_IO_IOCTL_H_