mirror of
https://github.com/BigfootACA/arch-image-builder.git
synced 2024-09-21 17:30:55 +08:00
107 lines
2.9 KiB
Python
107 lines
2.9 KiB
Python
import ctypes
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from logging import getLogger
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from builder.lib.serializable import SerializableDict
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from builder.disk.layout.mbr.types import DiskTypesMBR
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log = getLogger(__name__)
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class MbrPartEntry(ctypes.Structure, SerializableDict):
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_fields_ = [
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("boot_indicator", ctypes.c_uint8),
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("start_head", ctypes.c_uint8),
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("start_sector", ctypes.c_uint8),
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("start_track", ctypes.c_uint8),
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("os_indicator", ctypes.c_uint8),
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("end_head", ctypes.c_uint8),
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("end_sector", ctypes.c_uint8),
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("end_track", ctypes.c_uint8),
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("start_lba", ctypes.c_uint32),
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("size_lba", ctypes.c_uint32),
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]
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heads: int=255
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sectors: int=63
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def is_bootable(self) -> bool:
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return self.boot_indicator == 0x80
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def set_bootable(self, bootable: bool):
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self.boot_indicator = 0x80 if bootable else 0
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def get_type_name(self) -> str:
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return DiskTypesMBR.lookup_one_name(self.os_indicator)
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def get_type_id(self) -> int:
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return DiskTypesMBR.lookup_one_id(self.os_indicator)
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def set_type(self, t: int|str):
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g = DiskTypesMBR.lookup_one_id(t)
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if g is None: raise ValueError(f"bad type {t}")
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self.os_indicator = g
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def set_start_lba(self, start_lba: int):
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c, h, s = lba_to_chs(start_lba, self.sectors, self.heads)
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self.start_head = h
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self.start_sector = s
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self.start_track = c
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self.start_lba = start_lba
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def set_end_lba(self, end_lba: int):
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c, h, s = lba_to_chs(end_lba, self.sectors, self.heads)
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self.end_head = h
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self.end_sector = s
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self.end_track = c
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self.size_lba = end_lba - self.start_lba + 1
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def set_size_lba(self, size_lba: int):
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end_lba = size_lba + self.start_lba - 1
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c, h, s = lba_to_chs(end_lba, self.sectors, self.heads)
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self.end_head = h
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self.end_sector = s
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self.end_track = c
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self.size_lba = size_lba
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def to_dict(self) -> dict:
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ret = {field[0]: getattr(self, field[0]) for field in self._fields_}
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ret["bootable"] = self.is_bootable()
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ret["type_id"] = self.get_type_id()
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ret["type_name"] = self.get_type_name()
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return ret
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class MasterBootRecord(ctypes.Structure, SerializableDict):
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_pack_ = 1
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_fields_ = [
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("boot_code", ctypes.c_byte * 440),
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("mbr_id", ctypes.c_uint32),
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("reserved", ctypes.c_uint16),
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("partitions", MbrPartEntry * 4),
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("signature", ctypes.c_uint16),
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]
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MBR_SIGNATURE: int = 0xaa55
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def fill_header(self):
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self.signature = self.MBR_SIGNATURE
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def check_signature(self) -> bool:
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return self.signature == self.MBR_SIGNATURE
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def to_dict(self) -> dict:
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parts = [part for part in self.partitions if part.os_indicator != 0]
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return {
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"mbr_id": f"{self.mbr_id:08x}",
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"partitions": parts,
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"signature": self.signature,
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}
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assert(ctypes.sizeof(MbrPartEntry()) == 16)
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assert(ctypes.sizeof(MasterBootRecord()) == 512)
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def lba_to_chs(lba: int, sectors: int = 63, heads: int = 255):
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lba += 1
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sector = lba % sectors
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head = (lba // sectors) % heads
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cylinder = lba // (sectors * heads)
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return cylinder, head, sector
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