/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * * Copyright (C) 2021 Aidan MacDonald * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "jztool.h" #include /* Following is copied from mkspl-x1000, basically */ struct x1000_spl_header { uint8_t magic[8]; uint8_t type; uint8_t crc7; uint8_t ppb; uint8_t bpp; uint32_t length; }; static const uint8_t x1000_spl_header_magic[8] = {0x06, 0x05, 0x04, 0x03, 0x02, 0x55, 0xaa, 0x55}; static const size_t X1000_SPL_HEADER_SIZE = 2 * 1024; static uint8_t crc7(const uint8_t* buf, size_t len) { /* table-based computation of CRC7 */ static const uint8_t t[256] = { 0x00, 0x09, 0x12, 0x1b, 0x24, 0x2d, 0x36, 0x3f, 0x48, 0x41, 0x5a, 0x53, 0x6c, 0x65, 0x7e, 0x77, 0x19, 0x10, 0x0b, 0x02, 0x3d, 0x34, 0x2f, 0x26, 0x51, 0x58, 0x43, 0x4a, 0x75, 0x7c, 0x67, 0x6e, 0x32, 0x3b, 0x20, 0x29, 0x16, 0x1f, 0x04, 0x0d, 0x7a, 0x73, 0x68, 0x61, 0x5e, 0x57, 0x4c, 0x45, 0x2b, 0x22, 0x39, 0x30, 0x0f, 0x06, 0x1d, 0x14, 0x63, 0x6a, 0x71, 0x78, 0x47, 0x4e, 0x55, 0x5c, 0x64, 0x6d, 0x76, 0x7f, 0x40, 0x49, 0x52, 0x5b, 0x2c, 0x25, 0x3e, 0x37, 0x08, 0x01, 0x1a, 0x13, 0x7d, 0x74, 0x6f, 0x66, 0x59, 0x50, 0x4b, 0x42, 0x35, 0x3c, 0x27, 0x2e, 0x11, 0x18, 0x03, 0x0a, 0x56, 0x5f, 0x44, 0x4d, 0x72, 0x7b, 0x60, 0x69, 0x1e, 0x17, 0x0c, 0x05, 0x3a, 0x33, 0x28, 0x21, 0x4f, 0x46, 0x5d, 0x54, 0x6b, 0x62, 0x79, 0x70, 0x07, 0x0e, 0x15, 0x1c, 0x23, 0x2a, 0x31, 0x38, 0x41, 0x48, 0x53, 0x5a, 0x65, 0x6c, 0x77, 0x7e, 0x09, 0x00, 0x1b, 0x12, 0x2d, 0x24, 0x3f, 0x36, 0x58, 0x51, 0x4a, 0x43, 0x7c, 0x75, 0x6e, 0x67, 0x10, 0x19, 0x02, 0x0b, 0x34, 0x3d, 0x26, 0x2f, 0x73, 0x7a, 0x61, 0x68, 0x57, 0x5e, 0x45, 0x4c, 0x3b, 0x32, 0x29, 0x20, 0x1f, 0x16, 0x0d, 0x04, 0x6a, 0x63, 0x78, 0x71, 0x4e, 0x47, 0x5c, 0x55, 0x22, 0x2b, 0x30, 0x39, 0x06, 0x0f, 0x14, 0x1d, 0x25, 0x2c, 0x37, 0x3e, 0x01, 0x08, 0x13, 0x1a, 0x6d, 0x64, 0x7f, 0x76, 0x49, 0x40, 0x5b, 0x52, 0x3c, 0x35, 0x2e, 0x27, 0x18, 0x11, 0x0a, 0x03, 0x74, 0x7d, 0x66, 0x6f, 0x50, 0x59, 0x42, 0x4b, 0x17, 0x1e, 0x05, 0x0c, 0x33, 0x3a, 0x21, 0x28, 0x5f, 0x56, 0x4d, 0x44, 0x7b, 0x72, 0x69, 0x60, 0x0e, 0x07, 0x1c, 0x15, 0x2a, 0x23, 0x38, 0x31, 0x46, 0x4f, 0x54, 0x5d, 0x62, 0x6b, 0x70, 0x79 }; uint8_t crc = 0; while(len--) crc = t[(crc << 1) ^ *buf++]; return crc; } /** \brief Identify a file as an SPL for X1000 CPUs * \param data File data buffer * \param len Length of file * \return JZ_SUCCESS if file looks correct, or one of the following errors * \retval JZ_IDERR_WRONG_SIZE file too small or size doesn't match header * \retval JZ_IDERR_BAD_HEADER missing magic bytes from header * \retval JZ_IDERR_BAD_CHECKSUM CRC7 mismatch */ int jz_identify_x1000_spl(const void* data, size_t len) { /* Use <= check because a header-only file is not really valid, * it should have at least one byte in it... */ if(len <= X1000_SPL_HEADER_SIZE) return JZ_IDERR_WRONG_SIZE; /* Look for header magic bytes */ const struct x1000_spl_header* header = (const struct x1000_spl_header*)data; if(memcmp(header->magic, x1000_spl_header_magic, 8)) return JZ_IDERR_BAD_HEADER; /* Length stored in the header should equal the length of the file */ if(header->length != len) return JZ_IDERR_WRONG_SIZE; /* Compute the CRC7 checksum; it only covers the SPL code */ const uint8_t* dat = (const uint8_t*)data; uint8_t sum = crc7(&dat[X1000_SPL_HEADER_SIZE], len - X1000_SPL_HEADER_SIZE); if(header->crc7 != sum) return JZ_IDERR_BAD_CHECKSUM; return JZ_SUCCESS; } static const struct scramble_model_info { const char* name; int model_num; size_t offset_crc; size_t offset_name; size_t offset_data; } scramble_models[] = { {"fiio", 114, 0, 4, 8}, {"shq1", 115, 0, 4, 8}, {"eros", 116, 0, 4, 8}, {NULL, 0, 0, 0, 0}, }; /** \brief Identify a file as a Rockbox `scramble` image * \param data File data buffer * \param len Length of file * \return JZ_SUCCESS if file looks correct, or one of the following errors * \retval JZ_IDERR_UNRECOGNIZED_MODEL unsupported/unknown model type * \retval JZ_IDERR_BAD_CHECKSUM checksum mismatch */ int jz_identify_scramble_image(const void* data, size_t len) { const uint8_t* dat; const struct scramble_model_info* model_info; uint32_t sum, file_sum; dat = (const uint8_t*)data; model_info = &scramble_models[0]; /* Look up the model number */ for(; model_info->name != NULL; ++model_info) { if(model_info->offset_name + 4 > len) continue; if(!memcmp(&dat[model_info->offset_name], model_info->name, 4)) break; } if(model_info->name == NULL) return JZ_IDERR_UNRECOGNIZED_MODEL; /* Compute the checksum */ sum = model_info->model_num; for(size_t i = model_info->offset_data; i < len; ++i) sum += dat[i]; /* Compare with file's checksum, it's stored in big-endian form */ dat += model_info->offset_crc; file_sum = (dat[0] << 24) | (dat[1] << 16) | (dat[2] << 8) | dat[3]; if(sum != file_sum) return JZ_IDERR_BAD_CHECKSUM; return JZ_SUCCESS; }