esp-idf/components/fatfs/fatfsgen.py

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#!/usr/bin/env python
# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
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# 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
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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:
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"""
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()
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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:
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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')
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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)
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fatfs.generate(input_dir)
fatfs.write_filesystem(args.output_file)