proddata/mtd_access.cpp

/*
 * 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.
 */

/**
 * @file
 *  MTDAccess class
 *
 * @author Imagination Technologies
 *
 * @copyright <b>Copyright 2016 by Imagination Technologies Limited and/or its affiliated group companies.</b>
 */

#include "mtd_access.h"
#ifdef __ANDROID__
#include <android-base/logging.h>
#define DLOG(x) LOG(x)
#else
#include <glog/logging.h>
#endif
#include <fcntl.h>
#include <sys/ioctl.h>
#include <stdexcept>

MTDAccess::MTDAccess(const std::string &device_name) : FlashAccess(device_name) {
  DLOG(INFO) << "Initialising MTDAccess";
  if (ioctl(fd_, MEMGETINFO, &mtd_info_) < 0) {
    DLOG(ERROR) << "ioctl failed and returned error: " << strerror(errno);
    close(fd_);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("MTDAccess Initialization failed");
#endif
  }
}

MTDAccess::~MTDAccess() {
  DLOG(INFO) << "Deinitialising MTDAccess";
}

/**
 * Replace vector content with replacement vector from specified position
 *
 * @param[out] data vector whose content is to be replaced
 * @param[in] replacement_vector replacement vector
 * @param[in] position position in the vector from where content is to be replaced
 */

static void replace(std::vector<uint8_t> *data, const std::vector<uint8_t> &replacement_vector,
                    int position) {
  auto erase_end = data->begin() + position + replacement_vector.size();

  if (erase_end > data->end()) { /* data should fit in 1st sector of mtd device */
#ifdef __ANDROID__
    LOG(ERROR) << "Cannot replace content of vector with replacement vector";
    exit(-1);
#else
    throw std::runtime_error("Cannot replace content of vector with replacement vector");
#endif
  }

  data->erase(data->begin() + position, erase_end);
  data->insert(data->begin() + position, replacement_vector.begin(), replacement_vector.end());
}

void MTDAccess::Write(const std::vector<uint8_t> &buf, const int offset) {
  int sector_size = mtd_info_.erasesize;

  /* read sector (note : it is assumed that all the device data will be on 1st sector) */
  std::vector<uint8_t> read_buf = this->Read(sector_size, 0);

  /* erase sector */
  erase_info_t ei;
  ei.length = mtd_info_.erasesize;
  ei.start = 0;
  if (ioctl(fd_, MEMERASE, &ei) < 0) {
    DLOG(ERROR) << "ioctl failed and returned error: " << strerror(errno);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("mtd write: ioctl failed");
#endif
  }
  /* modify sector */
  replace(&read_buf, buf, offset);

  /* write sector */
  if (lseek(fd_, 0, SEEK_SET) < 0) {
    DLOG(ERROR) << "mtd write: lseek failed:" << strerror(errno);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("mtd write: lseek failed");
#endif
  }

  int ret = write(fd_, read_buf.data(), sector_size);
  if (ret < 0) {
    DLOG(ERROR) << "mtd write failed:" << strerror(errno);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("mtd write failed");
#endif
  }
}

std::vector<uint8_t> MTDAccess::Read(const int size, const int offset) {
  std::vector<uint8_t> buf(size);
  if (lseek(fd_, offset, SEEK_SET) < 0) {
    DLOG(ERROR) << "mtd read: lseek failed:" << strerror(errno);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("mtd read: lseek failed");
#endif
  }

  int ret = read(fd_, buf.data(), buf.size());
  if (ret < 0) {
    DLOG(ERROR) << "mtd read failed:" << strerror(errno);
#ifdef __ANDROID__
    exit(-1);
#else
    throw std::runtime_error("mtd read failed");
#endif
  }
  return buf;
}