utility.cpp

/*
  Copyright (c) 2017 Arduino LLC.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/**************************************************************************************
   INCLUDE
 **************************************************************************************/

#include "lzss.h"

#include "Arduino_Portenta_OTA.h"

/**************************************************************************************
   CONST
 **************************************************************************************/

const char * UPDATE_FILE_NAME      = "/fs/UPDATE.BIN";
const char * UPDATE_FILE_NAME_LZSS = "/fs/UPDATE.BIN.LZSS";

static const uint32_t crc_table[256] =
{
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
    0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

/**************************************************************************************
   FUNCTIONS
 **************************************************************************************/

uint32_t crc_update(uint32_t crc, const void * data, size_t data_len)
{
  const unsigned char *d = (const unsigned char *)data;
  unsigned int tbl_idx;

  while (data_len--) {
    tbl_idx = (crc ^ *d) & 0xff;
    crc = (crc_table[tbl_idx] ^ (crc >> 8)) & 0xffffffff;
    d++;
  }

  return crc & 0xffffffff;
}

/**************************************************************************************
   MAIN
 **************************************************************************************/

union HeaderVersion
{
  struct __attribute__((packed))
  {
    uint32_t header_version    :  6;
    uint32_t compression       :  1;
    uint32_t signature         :  1;
    uint32_t spare             :  4;
    uint32_t payload_target    :  4;
    uint32_t payload_major     :  8;
    uint32_t payload_minor     :  8;
    uint32_t payload_patch     :  8;
    uint32_t payload_build_num : 24;
  } field;
  uint8_t buf[sizeof(field)];
  static_assert(sizeof(buf) == 8, "Error: sizeof(HEADER.VERSION) != 8");
};

union OTAHeader
{
  struct __attribute__((packed))
  {
    uint32_t len;
    uint32_t crc32;
    uint32_t magic_number;
    HeaderVersion hdr_version;
  } header;
  uint8_t buf[sizeof(header)];
  static_assert(sizeof(buf) == 20, "Error: sizeof(HEADER) != 20");
};

int Arduino_Portenta_OTA::download(const char * url, bool const is_https, MbedSocketClass * socket)
{
  return socket->download((char *)url, UPDATE_FILE_NAME_LZSS, is_https);
}

int Arduino_Portenta_OTA::downloadAndDecompress(const char * url, bool const is_https, MbedSocketClass * socket) {
  int res=0;

  FILE* decompressed = fopen(UPDATE_FILE_NAME, "wb");
  OTAHeader ota_header;

  LZSSDecoder decoder([&decompressed](const uint8_t c) {
    fwrite(&c, 1, 1, decompressed);
  });

  enum OTA_DOWNLOAD_STATE: uint8_t {
    OTA_DOWNLOAD_HEADER=0,
    OTA_DOWNLOAD_FILE,
    OTA_DOWNLOAD_ERR
  };

  // since mbed::Callback requires a function to not exceed a certain size, we group the following parameters in a struct
  struct {
    uint32_t crc32 = 0xFFFFFFFF;
    uint32_t header_copied_bytes = 0;
    OTA_DOWNLOAD_STATE state=OTA_DOWNLOAD_HEADER;
    Arduino_Portenta_OTA* ref;
  } ota_progress;

  ota_progress.ref = this;

  int bytes = socket->download(url, is_https, [ &decoder, &ota_header, &ota_progress](const char* buffer, uint32_t size) {
    ota_progress.ref->feedWatchdog();
    for(char* cursor=(char*)buffer; cursor<buffer+size; ) {
      switch(ota_progress.state) {
        case OTA_DOWNLOAD_HEADER: {
          // read to ota_header.buf
          // the header could be split into two arrivals, we must handle that
          uint32_t copied = size < sizeof(ota_header.buf) ? size : sizeof(ota_header.buf);
          memcpy(ota_header.buf, buffer, copied);
          cursor += copied;
          ota_progress.header_copied_bytes += copied;

          // when finished go to next state
          if(sizeof(ota_header.buf) == ota_progress.header_copied_bytes) {
            ota_progress.state = OTA_DOWNLOAD_FILE;

            ota_progress.crc32 = crc_update(
              ota_progress.crc32,
              &(ota_header.header.magic_number),
              sizeof(ota_header) - offsetof(OTAHeader, header.magic_number)
            );

          }
          break;
        }
        case OTA_DOWNLOAD_FILE:
          // continue to download the payload, decompressing it and calculate crc
          decoder.decompress((uint8_t*)cursor, size - (cursor-buffer));
          ota_progress.crc32 = crc_update(
              ota_progress.crc32,
              cursor,
              size - (cursor-buffer)
            );

          cursor += size - (cursor-buffer);
          break;
        default:
          ota_progress.state = OTA_DOWNLOAD_ERR;
      }
    }
  });

  // if download fails it return a negative error code
  if(bytes <= 0) {
    res = bytes;
    goto exit;
  }

  // if state is download finished and completed correctly the state should be OTA_DOWNLOAD_FILE
  if(ota_progress.state != OTA_DOWNLOAD_FILE) {
    res = static_cast<int>(Error::OtaDownload);
    goto exit;
  }

  if(ota_header.header.len == (bytes-sizeof(ota_header.buf))) {
    res = static_cast<int>(Error::OtaHeaderLength);
    goto exit;
  }

  // verify magic number: it may be done in the download function and stop the download immediately
  if(ota_header.header.magic_number != ARDUINO_PORTENTA_OTA_MAGIC) {
    res = static_cast<int>(Error::OtaHeaterMagicNumber);
    goto exit;
  }

  // finalize CRC and verify it
  ota_progress.crc32 ^= 0xFFFFFFFF;
  if(ota_header.header.crc32 != ota_progress.crc32) {
    res = static_cast<int>(Error::OtaHeaderCrc);
    goto exit;
  }

  res = ftell(decompressed);

exit:
  fclose(decompressed);

  if(res < 0) {
    remove(UPDATE_FILE_NAME);
  }

  return res;
}


int Arduino_Portenta_OTA::decompress()
{
  struct stat stat_buf;
  stat(UPDATE_FILE_NAME_LZSS, &stat_buf);
  auto update_file_size = stat_buf.st_size;

  /* For UPDATE.BIN.LZSS - LZSS compressed binary files. */
  FILE* update_file = fopen(UPDATE_FILE_NAME_LZSS, "rb");

  OTAHeader ota_header;
  uint32_t crc32, bytes_read;
  uint8_t crc_buf[128];

  feedWatchdog();

  /* Read the OTA header ... */
  fread(ota_header.buf, 1, sizeof(ota_header.buf), update_file);

  /* ... and check first length ... */
  if (ota_header.header.len != (update_file_size - sizeof(ota_header.header.len) - sizeof(ota_header.header.crc32))) {
    fclose(update_file);
    remove(UPDATE_FILE_NAME_LZSS);
    return static_cast<int>(Error::OtaHeaderLength);
  }

  feedWatchdog();

  /* ... and the CRC second ... rewind to start of CRC verified header ... */
  fseek(update_file, sizeof(ota_header.header.len) + sizeof(ota_header.header.crc32), SEEK_SET);
  /* ... initialize CRC ... */
  crc32 = 0xFFFFFFFF;
  /* ... and calculate over file ... */
  for(bytes_read = 0;
      bytes_read < (ota_header.header.len - sizeof(crc_buf));
      bytes_read += sizeof(crc_buf))
  {
    fread(crc_buf, 1, sizeof(crc_buf), update_file);
    crc32 = crc_update(crc32, crc_buf, sizeof(crc_buf));
  }
  fread(crc_buf, 1, ota_header.header.len - bytes_read, update_file);
  crc32 = crc_update(crc32, crc_buf, ota_header.header.len - bytes_read);

  feedWatchdog();

  /* ... then finalise ... */
  crc32 ^= 0xFFFFFFFF;
  /* ... and compare. */
  if (ota_header.header.crc32 != crc32) {
    fclose(update_file);
    remove(UPDATE_FILE_NAME_LZSS);
    return static_cast<int>(Error::OtaHeaderCrc);
  }

  feedWatchdog();

  if (ota_header.header.magic_number != ARDUINO_PORTENTA_OTA_MAGIC)
  {
    fclose(update_file);
    remove(UPDATE_FILE_NAME_LZSS);
    return static_cast<int>(Error::OtaHeaterMagicNumber);
  }

  /* Rewind to start of LZSS compressed binary. */
  fseek(update_file, sizeof(ota_header.buf), SEEK_SET);

  uint32_t const LZSS_FILE_SIZE = update_file_size - sizeof(ota_header.buf);

  FILE* decompressed = fopen(UPDATE_FILE_NAME, "w");

  lzss_init(update_file, decompressed, LZSS_FILE_SIZE, _feed_watchdog_func);

  /* During the process of decoding UPDATE.BIN.LZSS
   * is decompressed and stored as UPDATE.BIN.
   */
  lzss_decode();
  /* Write the data remaining in the write buffer to
   * the file.
   */
  lzss_flush();

  /* Determine the size of the decompressed file. */
  int const decompressed_file_size = ftell(decompressed);

  /* Delete UPDATE.BIN.LZSS because this update is complete. */
  fclose(update_file);
  fclose(decompressed);
  remove(UPDATE_FILE_NAME_LZSS);

  return decompressed_file_size;
}