One-KVM/kvmd/kvmd/msd.py
2018-07-03 07:00:17 +03:00

268 lines
9.0 KiB
Python

import os
import struct
import asyncio
import types
from typing import Dict
from typing import NamedTuple
from typing import Callable
from typing import Type
from typing import Optional
from typing import Any
import pyudev
import aiofiles
import aiofiles.base
from .logging import get_logger
# =====
class MassStorageError(Exception):
pass
class IsNotOperationalError(MassStorageError):
def __init__(self) -> None:
super().__init__("Missing bind for mass-storage device")
class AlreadyConnectedToPcError(MassStorageError):
def __init__(self) -> None:
super().__init__("Mass-storage is already connected to Server")
class AlreadyConnectedToKvmError(MassStorageError):
def __init__(self) -> None:
super().__init__("Mass-storage is already connected to KVM")
class IsNotConnectedToKvmError(MassStorageError):
def __init__(self) -> None:
super().__init__("Mass-storage is not connected to KVM")
class IsBusyError(MassStorageError):
def __init__(self) -> None:
super().__init__("Mass-storage is busy (write in progress)")
class DeviceInfo(NamedTuple):
path: str
bind: str
size: int
manufacturer: str
product: str
serial: str
image_name: str
_DISK_META_SIZE = 4096
_DISK_META_MAGIC_SIZE = 16
_DISK_META_IMAGE_NAME_SIZE = 256
_DISK_META_PADS_SIZE = _DISK_META_SIZE - _DISK_META_IMAGE_NAME_SIZE - _DISK_META_MAGIC_SIZE * 8
_DISK_META_FORMAT = ">%dL%dc%dx%dL" % (
_DISK_META_MAGIC_SIZE,
_DISK_META_IMAGE_NAME_SIZE,
_DISK_META_PADS_SIZE,
_DISK_META_MAGIC_SIZE,
)
_DISK_META_MAGIC = [0x1ACE1ACE] * _DISK_META_MAGIC_SIZE
def _make_disk_meta(image_name: str) -> bytes:
return struct.pack(
_DISK_META_FORMAT,
*_DISK_META_MAGIC,
*memoryview(( # type: ignore
image_name.encode("utf-8")
+ b"\x00" * _DISK_META_IMAGE_NAME_SIZE
)[:_DISK_META_IMAGE_NAME_SIZE]).cast("c"),
*_DISK_META_MAGIC,
)
def _parse_disk_meta(data: bytes) -> Dict:
disk_meta = {"image_name": ""}
try:
parsed = list(struct.unpack(_DISK_META_FORMAT, data))
except struct.error:
pass
else:
magic_begin = parsed[:_DISK_META_MAGIC_SIZE]
magic_end = parsed[-_DISK_META_MAGIC_SIZE:]
if magic_begin == magic_end == _DISK_META_MAGIC:
image_name_bytes = b"".join(parsed[_DISK_META_MAGIC_SIZE:_DISK_META_MAGIC_SIZE + _DISK_META_IMAGE_NAME_SIZE])
disk_meta["image_name"] = image_name_bytes.decode("utf-8", errors="ignore").strip("\x00").strip()
return disk_meta
def explore_device(path: str) -> DeviceInfo:
# udevadm info -a -p $(udevadm info -q path -n /dev/sda)
ctx = pyudev.Context()
block_device = pyudev.Devices.from_device_file(ctx, path)
size = block_device.attributes.asint("size") * 512
storage_device = block_device.find_parent("usb", "usb_interface")
assert storage_device.driver == "usb-storage", (storage_device.driver, storage_device)
usb_device = block_device.find_parent("usb", "usb_device")
assert usb_device.driver == "usb", (usb_device.driver, usb_device)
with open(path, "rb") as device_file:
device_file.seek(size - _DISK_META_SIZE)
disk_meta = _parse_disk_meta(device_file.read())
return DeviceInfo(
path=path,
bind=storage_device.sys_name,
size=size,
manufacturer=usb_device.attributes.asstring("manufacturer").strip(),
product=usb_device.attributes.asstring("product").strip(),
serial=usb_device.attributes.asstring("serial").strip(),
image_name=disk_meta["image_name"],
)
def locate_by_bind(bind: str) -> str:
ctx = pyudev.Context()
for device in ctx.list_devices(subsystem="block"):
storage_device = device.find_parent("usb", "usb_interface")
if storage_device:
try:
device.attributes.asint("partititon")
except KeyError:
if storage_device.sys_name == bind:
return os.path.join("/dev", device.sys_name)
return ""
def _operated_and_locked(method: Callable) -> Callable:
async def wrap(self: "MassStorageDevice", *args: Any, **kwargs: Any) -> Any:
if self._device_file: # pylint: disable=protected-access
raise IsBusyError()
if not self._bind: # pylint: disable=protected-access
IsNotOperationalError()
async with self._lock: # pylint: disable=protected-access
return (await method(self, *args, **kwargs))
return wrap
class MassStorageDevice: # pylint: disable=too-many-instance-attributes
def __init__(self, bind: str, init_delay: float, write_meta: bool, loop: asyncio.AbstractEventLoop) -> None:
self._bind = bind
self.__init_delay = init_delay
self.__write_meta = write_meta
self.__loop = loop
self.__device_info: Optional[DeviceInfo] = None
self._lock = asyncio.Lock()
self._device_file: Optional[aiofiles.base.AiofilesContextManager] = None
self.__writed = 0
logger = get_logger(0)
if self._bind:
logger.info("Using bind %r as mass-storage device", self._bind)
try:
logger.info("Enabled metadata writing")
loop.run_until_complete(self.connect_to_kvm(no_delay=True))
except Exception as err:
if isinstance(err, MassStorageError):
log = logger.error
else:
log = logger.exception
log("Mass-storage device is not operational: %s", err)
self._bind = ""
else:
logger.warning("Missing bind; mass-storage device is not operational")
@_operated_and_locked
async def connect_to_kvm(self, no_delay: bool=False) -> None:
if self.__device_info:
raise AlreadyConnectedToKvmError()
# TODO: disable gpio
if not no_delay:
await asyncio.sleep(self.__init_delay)
await self.__reread_device_info()
get_logger().info("Mass-storage device switched to KVM: %s", self.__device_info)
@_operated_and_locked
async def connect_to_pc(self) -> None:
if not self.__device_info:
raise AlreadyConnectedToPcError()
# TODO: enable gpio
self.__device_info = None
get_logger().info("Mass-storage device switched to Server")
def get_state(self) -> Dict:
return {
"in_operate": bool(self._bind),
"connected_to": ("kvm" if self.__device_info else "server"),
"is_busy": bool(self._device_file),
"writed": self.__writed,
"info": (self.__device_info._asdict() if self.__device_info else None),
}
async def cleanup(self) -> None:
async with self._lock:
await self.__close_device_file()
# TODO: disable gpio
@_operated_and_locked
async def __aenter__(self) -> "MassStorageDevice":
if not self.__device_info:
raise IsNotConnectedToKvmError()
self._device_file = await aiofiles.open(self.__device_info.path, mode="wb", buffering=0)
self.__writed = 0
return self
async def write_image_name(self, image_name: str) -> None:
async with self._lock:
assert self._device_file
assert self.__device_info
if self.__write_meta:
await self._device_file.seek(self.__device_info.size - _DISK_META_SIZE)
await self._device_file.write(_make_disk_meta(image_name))
await self._device_file.flush()
await self.__loop.run_in_executor(None, os.fsync, self._device_file.fileno())
await self._device_file.seek(0)
await self.__reread_device_info()
async def write_image_chunk(self, chunk: bytes) -> int:
async with self._lock:
assert self._device_file
size = len(chunk)
await self._device_file.write(chunk)
await self._device_file.flush()
await self.__loop.run_in_executor(None, os.fsync, self._device_file.fileno())
self.__writed += size
return self.__writed
async def __aexit__(
self,
_exc_type: Type[BaseException],
_exc: BaseException,
_tb: types.TracebackType,
) -> None:
async with self._lock:
await self.__close_device_file()
async def __reread_device_info(self) -> None:
path = await self.__loop.run_in_executor(None, locate_by_bind, self._bind)
if not path:
raise MassStorageError("Can't locate device by bind %r" % (self._bind))
self.__device_info = await self.__loop.run_in_executor(None, explore_device, path)
async def __close_device_file(self) -> None:
try:
if self._device_file:
get_logger().info("Closing mass-storage device file ...")
await self._device_file.close()
except Exception:
get_logger().exception("Can't close mass-storage device file")
# TODO: reset device file
self._device_file = None
self.__writed = 0