#!/usr/bin/env python # SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD # SPDX-License-Identifier: Apache-2.0 import os from typing import Any, List, Optional from construct import Const, Int8ul, Int16ul, Int32ul, PaddedString, Struct from fatfsgen_utils.fat import FAT from fatfsgen_utils.fatfs_state import FATFSState from fatfsgen_utils.fs_object import Directory from fatfsgen_utils.utils import generate_4bytes_random, get_args_for_partition_generator, pad_string class FATFS: """ The class FATFS provides API for generating FAT file system. It contains reference to the FAT table and to the root directory. """ MAX_VOL_LAB_SIZE = 11 MAX_OEM_NAME_SIZE = 8 MAX_FS_TYPE_SIZE = 8 BOOT_HEADER_SIZE = 512 BOOT_SECTOR_HEADER = Struct( 'BS_jmpBoot' / Const(b'\xeb\xfe\x90'), 'BS_OEMName' / PaddedString(MAX_OEM_NAME_SIZE, 'utf-8'), 'BPB_BytsPerSec' / Int16ul, 'BPB_SecPerClus' / Int8ul, 'BPB_RsvdSecCnt' / Int16ul, 'BPB_NumFATs' / Int8ul, 'BPB_RootEntCnt' / Int16ul, 'BPB_TotSec16' / Int16ul, 'BPB_Media' / Int8ul, 'BPB_FATSz16' / Int16ul, 'BPB_SecPerTrk' / Int16ul, 'BPB_NumHeads' / Int16ul, 'BPB_HiddSec' / Int32ul, 'BPB_TotSec32' / Int32ul, 'BS_DrvNum' / Const(b'\x80'), 'BS_Reserved1' / Const(b'\x00'), 'BS_BootSig' / Const(b'\x29'), 'BS_VolID' / Int32ul, 'BS_VolLab' / PaddedString(MAX_VOL_LAB_SIZE, 'utf-8'), 'BS_FilSysType' / PaddedString(MAX_FS_TYPE_SIZE, 'utf-8'), 'BS_EMPTY' / Const(448 * b'\x00'), 'Signature_word' / Const(b'\x55\xAA') ) def __init__(self, binary_image_path: Optional[str] = None, size: int = 1024 * 1024, reserved_sectors_cnt: int = 1, fat_tables_cnt: int = 1, sectors_per_cluster: int = 1, sector_size: int = 0x1000, sectors_per_fat: int = 1, root_dir_sectors_cnt: int = 4, hidden_sectors: int = 0, long_names_enabled: bool = False, entry_size: int = 32, num_heads: int = 0xff, oem_name: str = 'MSDOS5.0', sec_per_track: int = 0x3f, volume_label: str = 'Espressif', file_sys_type: str = 'FAT', media_type: int = 0xf8) -> None: self.state = FATFSState(entry_size=entry_size, sector_size=sector_size, reserved_sectors_cnt=reserved_sectors_cnt, root_dir_sectors_cnt=root_dir_sectors_cnt, size=size, file_sys_type=file_sys_type, num_heads=num_heads, fat_tables_cnt=fat_tables_cnt, sectors_per_fat=sectors_per_fat, sectors_per_cluster=sectors_per_cluster, media_type=media_type, hidden_sectors=hidden_sectors, sec_per_track=sec_per_track, long_names_enabled=long_names_enabled, volume_label=volume_label, oem_name=oem_name) binary_image = bytearray( self.read_filesystem(binary_image_path) if binary_image_path else self.create_empty_fatfs()) self.state.binary_image = binary_image self.fat = FAT(fatfs_state=self.state, reserved_sectors_cnt=self.state.reserved_sectors_cnt) self.root_directory = Directory(name='A', # the name is not important size=self.state.root_dir_sectors_cnt * self.state.sector_size, fat=self.fat, cluster=self.fat.clusters[1], fatfs_state=self.state) self.root_directory.init_directory() def create_file(self, name: str, extension: str = '', path_from_root: Optional[List[str]] = None) -> None: # when path_from_root is None the dir is root self.root_directory.new_file(name=name, extension=extension, path_from_root=path_from_root) def create_directory(self, name: str, path_from_root: Optional[List[str]] = None) -> None: # when path_from_root is None the dir is root parent_dir = self.root_directory if path_from_root: parent_dir = self.root_directory.recursive_search(path_from_root, self.root_directory) self.root_directory.new_directory(name=name, parent=parent_dir, path_from_root=path_from_root) def write_content(self, path_from_root: List[str], content: bytes) -> None: """ fat fs invokes root directory to recursively find the required file and writes the content """ self.root_directory.write_to_file(path_from_root, content) def create_empty_fatfs(self) -> Any: sectors_count = self.state.size // self.state.sector_size volume_uuid = generate_4bytes_random() return ( FATFS.BOOT_SECTOR_HEADER.build( dict(BS_OEMName=pad_string(self.state.oem_name, size=FATFS.MAX_OEM_NAME_SIZE), BPB_BytsPerSec=self.state.sectors_per_cluster * self.state.sector_size, BPB_SecPerClus=self.state.sectors_per_cluster, BPB_RsvdSecCnt=self.state.reserved_sectors_cnt, BPB_NumFATs=self.state.fat_tables_cnt, BPB_RootEntCnt=self.state.entries_root_count, BPB_TotSec16=0x00 if self.state.fatfs_type == FATFSState.FAT32 else sectors_count, BPB_Media=self.state.media_type, BPB_FATSz16=self.state.sectors_per_fat_cnt, BPB_SecPerTrk=self.state.sec_per_track, BPB_NumHeads=self.state.num_heads, BPB_HiddSec=self.state.hidden_sectors, BPB_TotSec32=sectors_count if self.state.fatfs_type == FATFSState.FAT32 else 0x00, BS_VolID=volume_uuid, BS_VolLab=pad_string(self.state.volume_label, size=FATFS.MAX_VOL_LAB_SIZE), BS_FilSysType=pad_string(self.state.file_sys_type, size=FATFS.MAX_FS_TYPE_SIZE) ) ) + (self.state.sector_size - FATFS.BOOT_HEADER_SIZE) * b'\x00' + self.state.sectors_per_fat_cnt * self.state.fat_tables_cnt * self.state.sector_size * b'\x00' + self.state.root_dir_sectors_cnt * self.state.sector_size * b'\x00' + self.state.data_sectors * self.state.sector_size * b'\xff' ) @staticmethod def read_filesystem(path: str) -> bytearray: with open(path, 'rb') as fs_file: return bytearray(fs_file.read()) def write_filesystem(self, output_path: str) -> None: with open(output_path, 'wb') as output: output.write(bytearray(self.state.binary_image)) def _generate_partition_from_folder(self, folder_relative_path: str, folder_path: str = '', is_dir: bool = False) -> None: """ Given path to folder and folder name recursively encodes folder into binary image. Used by method generate """ real_path = os.path.join(folder_path, folder_relative_path) smaller_path = folder_relative_path folder_relative_path = folder_relative_path.upper() normal_path = os.path.normpath(folder_relative_path) split_path = normal_path.split(os.sep) if os.path.isfile(real_path): with open(real_path, 'rb') as file: content = file.read() file_name, extension = os.path.splitext(split_path[-1]) extension = extension[1:] # remove the dot from the extension self.create_file(name=file_name, extension=extension, path_from_root=split_path[1:-1] or None) self.write_content(split_path[1:], content) elif os.path.isdir(real_path): if not is_dir: self.create_directory(split_path[-1], split_path[1:-1]) # sorting files for better testability dir_content = list(sorted(os.listdir(real_path))) for path in dir_content: self._generate_partition_from_folder(os.path.join(smaller_path, path), folder_path=folder_path) def generate(self, input_directory: str) -> None: """ Normalize path to folder and recursively encode folder to binary image """ path_to_folder, folder_name = os.path.split(input_directory) self._generate_partition_from_folder(folder_name, folder_path=path_to_folder, is_dir=True) if __name__ == '__main__': args = get_args_for_partition_generator('Create a FAT filesystem and populate it with directory content') input_dir = args.input_directory partition_size = int(str(args.partition_size), 0) sector_size_bytes = int(str(args.sector_size), 0) fatfs = FATFS(size=partition_size, sector_size=sector_size_bytes) fatfs.generate(input_dir) fatfs.write_filesystem(args.output_file)