platform/slpi/include/chre/target_platform/platform_nanoapp_base.h

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * 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.
 */

#ifndef CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_
#define CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_

#include <cstddef>
#include <cstdint>

#include "chre/platform/shared/nanoapp_support_lib_dso.h"
#include "chre/util/entry_points.h"

namespace chre {

/**
 * SLPI-specific nanoapp functionality.
 */
class PlatformNanoappBase {
 public:
  /**
   * Copies the supplied application binary data into a new buffer. The
   * application may be invalid - full checking and initialization happens just
   * before invoking start() nanoapp entry point.
   *
   * @param appId The unique app identifier associated with this binary
   * @param appVersion An application-defined version number
   * @param appBinary Buffer containing the complete ELF binary for this
   *        nanoapp, without any CHRE-specific header
   * @param appBinaryLen Size of appBinary, in bytes
   *
   * @return true if the allocation was successful
   */
  bool loadFromBuffer(uint64_t appId, uint32_t appVersion,
                      const void *appBinary, size_t appBinaryLen);

  /**
   * Associate this PlatformNanoapp with a nanoapp that is statically built into
   * the CHRE binary with the given app info structure.
   */
  void loadStatic(const struct chreNslNanoappInfo *appInfo);

  /**
   * @return true if the app's binary data is resident in memory, i.e. a
   *         previous call to loadFromBuffer() or loadStatic() was successful
   */
  bool isLoaded() const;

 protected:
  //! The app ID we received in the metadata alongside the nanoapp binary. This
  //! is also included in (and checked against) mAppInfo.
  uint64_t mExpectedAppId;

  //! The application-defined version number we received in the metadata
  //! alongside the nanoapp binary. This is also included in (and checked
  //! against) mAppInfo.
  uint32_t mExpectedAppVersion;

  //! Buffer containing the complete DSO binary
  void *mAppBinary = nullptr;
  size_t mAppBinaryLen = 0;

  //! The dynamic shared object (DSO) handle returned by dlopen[buf]()
  void *mDsoHandle = nullptr;

  //! Pointer to the app info structure within this nanoapp
  const struct chreNslNanoappInfo *mAppInfo = nullptr;

  //! Set to true if this app is built into the CHRE binary, and was loaded via
  //! loadStatic(). In this case, the member variables above are not valid or
  //! applicable.
  bool mIsStatic = false;

  /**
   * Calls dlopenbuf on the app binary, and fetches and validates the app info
   * pointer. This will result in execution of any on-load handlers (e.g. static
   * global constructors) in the nanoapp.
   *
   * @return true if the app was opened successfully and the app info structure
   *         passed validation
   */
  bool openNanoapp();

  /**
   * Releases the DSO handle if it was active, by calling dlclose(). This will
   * result in execution of any unload handlers in the nanoapp.
   */
  void closeNanoapp();
};

}  // namespace chre

#endif  // CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_