#!/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 fatfsgen_utils.fat import FAT
from fatfsgen_utils.fatfs_parser import FATFSParser
from fatfsgen_utils.fatfs_state import FATFSState
from fatfsgen_utils.fs_object import Directory
from fatfsgen_utils.utils import (BYTES_PER_DIRECTORY_ENTRY, FAT32, generate_4bytes_random,
get_args_for_partition_generator, pad_string, read_filesystem)
class FATFS:
"""
The class FATFS provides API for generating FAT file system.
It contains reference to the FAT table and to the root directory.
"""
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,
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',
root_entry_count: int = 512,
explicit_fat_type: int = None,
media_type: int = 0xf8) -> None:
assert (root_entry_count * BYTES_PER_DIRECTORY_ENTRY) % sector_size == 0
assert ((root_entry_count * BYTES_PER_DIRECTORY_ENTRY) // sector_size) % 2 == 0
root_dir_sectors_cnt = (root_entry_count * BYTES_PER_DIRECTORY_ENTRY) // sector_size
self.state = FATFSState(entry_size=entry_size,
sector_size=sector_size,
explicit_fat_type=explicit_fat_type,
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(
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, must be string
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 (
FATFSParser.BOOT_SECTOR_HEADER.build(
dict(BS_OEMName=pad_string(self.state.oem_name, size=FATFSParser.MAX_OEM_NAME_SIZE),
BPB_BytsPerSec=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 == 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 == FAT32 else 0x00,
BS_VolID=volume_uuid,
BS_VolLab=pad_string(self.state.volume_label, size=FATFSParser.MAX_VOL_LAB_SIZE),
BS_FilSysType=pad_string(self.state.file_sys_type, size=FATFSParser.MAX_FS_TYPE_SIZE)
)
)
+ (self.state.sector_size - FATFSParser.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'
)
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)
def main() -> None:
args = get_args_for_partition_generator('Create a FAT filesystem and populate it with directory content')
fatfs = FATFS(sector_size=args.sector_size,
sectors_per_cluster=args.sectors_per_cluster,
size=args.partition_size,
root_entry_count=args.root_entry_count,
explicit_fat_type=args.fat_type)
fatfs.generate(args.input_directory)
fatfs.write_filesystem(args.output_file)
if __name__ == '__main__':
main()