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109 lines
3.3 KiB
Python
109 lines
3.3 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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import os
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import sys
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import types
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import ctypes
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FDT_MAGIC = b"\xD0\x0D\xFE\xED"
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class fdt_header(ctypes.BigEndianStructure):
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_fields_ = [("magic", ctypes.c_uint),
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("totalsize", ctypes.c_uint),
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("off_dt_struct", ctypes.c_uint),
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("off_dt_strings", ctypes.c_uint),
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("off_mem_rsvmap", ctypes.c_uint),
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("version", ctypes.c_uint),
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("last_comp_version", ctypes.c_uint),
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("boot_cpuid_phys", ctypes.c_uint),
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("size_dt_strings", ctypes.c_uint),
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("size_dt_struct", ctypes.c_uint)]
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class fdt_reserve_entry(ctypes.BigEndianStructure):
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_fields_ = [("address", ctypes.c_uint64),
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("size", ctypes.c_uint64)]
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class fdt_node_header(ctypes.BigEndianStructure):
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_fields_ = [("tag", ctypes.c_uint),
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("name", ctypes.c_char * 128)]
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class fdt_property(ctypes.BigEndianStructure):
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_fields_ = [("tag", ctypes.c_uint),
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("len", ctypes.c_uint),
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("nameoff", ctypes.c_uint),
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("data", ctypes.c_char)]
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FDT_TAGSIZE = 4
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FDT_BEGIN_NODE = 0x1 # Start node: full name
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FDT_END_NODE = 0x2 # End node
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FDT_PROP = 0x3 # Property: name off, size, content
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FDT_NOP = 0x4 # nop
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FDT_END = 0x9
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FDT_V1_SIZE = 7 * 4
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FDT_V2_SIZE = FDT_V1_SIZE + 4
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FDT_V3_SIZE = FDT_V2_SIZE + 4
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FDT_V16_SIZE = FDT_V3_SIZE
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FDT_V17_SIZE = FDT_V16_SIZE + 4
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def get_dtb_totalsize(img, pos = 0, check = True):
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if img[pos:pos+4] != FDT_MAGIC:
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return -1
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hdrsize = ctypes.sizeof(fdt_header)
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dt = fdt_header.from_buffer_copy(img[pos:pos+hdrsize])
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if not check and dt.totalsize > hdrsize + 128:
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return dt.totalsize
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if dt.totalsize > hdrsize + 128:
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if dt.off_dt_struct > hdrsize and dt.off_dt_struct < dt.totalsize:
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if dt.off_dt_strings > hdrsize and dt.off_dt_strings < dt.totalsize:
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if dt.version == 17 and dt.last_comp_version == 16:
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if dt.boot_cpuid_phys == 0:
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if dt.size_dt_strings < dt.totalsize and dt.size_dt_struct < dt.totalsize:
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return dt.totalsize
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return -1
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def find_dtb(img, pos=0, maxsize = 256000):
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while True:
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k = img.find(FDT_MAGIC + b"\x00", pos)
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if k < 0:
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break
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pos = k + 4
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totalsize = get_dtb_totalsize(img, k, check = True)
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if totalsize > 0 and totalsize <= maxsize:
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return k, totalsize
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return None, None
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def get_dtb(img, pos=0):
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pos, size = find_dtb(img, pos)
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return img[pos:pos+size] if pos is not None else None
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def get_dtb_part_info(dtb, part_name):
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k = dtb.find(b'fixed-partitions\x00')
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if k <= 0:
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return None
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while True:
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k = dtb.find(b"partition@", k)
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if k < 0:
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break
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k = dtb.find(b"\x00", k) + 1
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k = (k + 3) & 0xFFFFFFFC
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k += 12
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n = dtb.find(b"\x00", k)
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name = dtb[k:n]
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name_len = len(name)
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name = name.decode('latin_1')
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if name != part_name:
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continue
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k += name_len + 1
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k = (k + 3) & 0xFFFFFFFC
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k += 12
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addr = int.from_bytes(dtb[k:k+4], byteorder='big')
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size = int.from_bytes(dtb[k+4:k+8], byteorder='big')
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return {'addr': addr, 'size': size, 'name': name}
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return None
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