findCopyInterruptLocation.py

# This script finds the last sector copied by GParted given an initial sector
# and an offset to the location of its copy.
#
# This is done simply by comparing sector number n to sector number
# n+<offset_of_copy>. If these match it increments n and continues.
#
#        *** WARNING: In its current form, this script is very slow! ***
#
# You may prefer to increment n by a much larger number to save time (simply
# modify numSectorsToIncrement), but this won't find the exact last copied
# sector, just one within your increment size.

import sys

n                   = 123456789   # <- EDIT THIS!
offset              = 314159      # <- EDIT THIS!
partitionName       = "/dev/sda3" # <- EDIT THIS!
numIncrementSectors = 1           # <- Possibly edit this...
bytesPerSector      = 512         # <- Only edit this if you know what you're doing

m=n+offset

partition=open(partitionName,'rb') # Open partition

#Read data at sector n
partition.seek(n*bytesPerSector,0)
nData=partition.read(1*bytesPerSector)
print("Initial sector data:\n\n" + nData + "\n")

#Read data at sector m
partition.seek(m*bytesPerSector,0)
mData=partition.read(1*bytesPerSector)

if (nData != mData):
    partition.close()
    sys.exit("Initial sectors don't match, are you sure your numbers are correct?")

print("Starting at sector offset " + str(m-numIncrementSectors))

while (nData == mData):
    n += numIncrementSectors             # Increment sector pointer
    partition.seek(n*bytesPerSector)     # Seek to pointer position
    nData=partition.read(bytesPerSector) # Read data at that position

    m += numIncrementSectors             # Same as above
    partition.seek(m*bytesPerSector)
    mData=partition.read(bytesPerSector)

    if (( m % (1024*1024*1024/512)) == 0): # Check how far we've got
        print("Offset: " + str(m/(1024*1024*1024/512)) + " GiB, current sector offset: " + str(m-numIncrementSectors))

print("Last matching original/copied sector has absolute offset: " + str(m-numIncrementSectors))
print("Last matching copied/original sector has absolute offset: " + str(n-numIncrementSectors))

partition.close() # Close partition