dCache NFS file handle decoder

decode.py

#!/usr/bin/env python

import sys
import struct
import binascii


def hexToByte(h):
  bytes = []
  h = ''.join( h.split(" ") )
  for i in range(0, len(h), 2):
    bytes.append( chr( int (h[i:i+2], 16 ) ) )
  return ''.join( bytes )

fh = sys.argv[1].upper()

version = struct.unpack('b', hexToByte(fh[0:2]) )[0]
magic = fh[2:8]
generation = struct.unpack('>i', hexToByte(fh[8:16]))[0]
index = struct.unpack('>i', hexToByte(fh[16:24]))[0]
t =   struct.unpack('b', hexToByte(fh[24:26]))[0]
l = struct.unpack('b', hexToByte(fh[26:28]) )[0]
handle = hexToByte(fh[28:])

INODE_TYPES = {
    0: "INODE",
    1: "TAG",
    2: "TAGS",
    3: "ID",
    4: "PATHOF",
    5: "PARENT",
    6: "NAMWOF",
    7: "PGET",
    8: "PSET",
    9: "CONST",
}

print 'version   :', version
print 'magic     :', magic
print 'generation:', generation
print 'index     :', index
print 'type      :', t
print 'opaque len:', l
print 'handle    :', fh[28:]
print "fsid      :", struct.unpack('b', hexToByte(fh[28:30]) )[0]

inodeType = struct.unpack('b', hexToByte(fh[30:32]) )[0]
print "inode type:", INODE_TYPES[inodeType]
idLen = struct.unpack('b', hexToByte(fh[32:34]) )[0]
print "id len    :", idLen
print "id        :", fh[34:34+idLen*2]
argsLen = struct.unpack('b', hexToByte(fh[34+idLen*2:36+idLen*2]) )[0]
print "args      :", binascii.a2b_hex(fh[36+idLen*2:])