123 lines
3.7 KiB
Python
123 lines
3.7 KiB
Python
# JTFTP - Python/AsyncIO TFTP Server
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# Copyright (C) 2022 Jeffrey C. Ollie
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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# Warning!!! This does not actually work because aiofiles does not support
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# usage outside of a context manager. See: https://github.com/Tinche/aiofiles/issues/139
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#
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import functools
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import logging
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import os
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import pathlib
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from typing import Callable
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from typing import TypeVar
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import aiofiles
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import aiofiles.os
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from jtftp.errors import AccessViolation
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from jtftp.filesystem import FileMode
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logger = logging.getLogger(__name__)
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RT = TypeVar("RT")
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def ensure_open(method: Callable[..., RT]) -> Callable[..., RT]:
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@functools.wraps(method)
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async def _impl(self, *args, **kwargs) -> RT:
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logger.debug("ensure open")
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if self.data is None:
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await self.open()
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return await method(self, *args, **kwargs)
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return _impl
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class OnDiskFile:
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path: bytes
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mode: FileMode
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data: aiofiles.threadpool.binary.AsyncFileIO | None
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closed: bool
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def __init__(self, path: pathlib.PosixPath, mode: FileMode):
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logger.debug(f"myfile {path} {mode}")
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self.path = path
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self.mode = mode
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self.data = None
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self.closed = True
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async def open(self) -> None:
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logger.debug("diskfile open")
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self.data = aiofiles.open(self.path, self.mode.value)
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self.closed = False
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@ensure_open
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async def length(self) -> int:
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logger.debug("diskfile length")
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cur = await self.data.seek(0, os.SEEK_CUR)
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logger.debug(f"diskfile cur {cur}")
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length = await self.data.seek(0, os.SEEK_END)
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logger.debug(f"diskfile len {length}")
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await self.data.seek(cur, os.SEEK_SET)
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return length
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@ensure_open
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async def seek(self, offset: int, whence: int) -> int:
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logger.debug(f"diskfile seek {offset} {whence}")
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return await self.data.seek(offset, whence)
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@ensure_open
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async def read(self, length: int) -> bytes:
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logger.debug(f"diskfile read {length}")
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return await self.data.read(length)
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@ensure_open
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async def write(self, data: bytes) -> int:
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logger.debug(f"diskfile write {len(data)}")
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return await self.data.write(data)
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@ensure_open
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async def close(self, complete: bool) -> None:
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logger.debug(f"diskfile close {complete}")
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self.closed = True
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if self.data is not None:
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await self.data.close()
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self.data = None
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class ReadOnlyOnDiskFilesystem:
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def __init__(self, root: pathlib.PosixPath):
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self.root = root.resolve()
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async def open(self, filename: bytes, mode: FileMode) -> OnDiskFile:
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path = self.root.joinpath(filename.decode("ascii")).resolve()
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try:
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path.relative_to(self.root)
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except ValueError:
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raise AccessViolation("illegal directory traversal")
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logger.debug(f"ro ondisk open {filename} {mode}")
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match mode:
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case FileMode.BINARY_READ:
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return OnDiskFile(path, mode)
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case FileMode.BINARY_WRITE:
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raise AccessViolation("read-only")
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case _:
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raise ValueError
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