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lab3b.py
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# NAME: Richard Tang
# EMAIL: [email protected]
# ID: 305348008
from enum import Enum
import sys
import csv
class Exit_Code(Enum):
NO_INCONSISTENCIES = 0
PROGRAM_ERROR = 1
INCONSISTENCIES_FOUND = 2
class EXT2_Filesystem():
def __init__(self):
self.num_of_blocks = None
self.num_of_inodes = None
self.block_size = None
self.inode_size = None
self.free_blocks = []
self.free_inodes = []
self.inodes = {}
self.directories = {}
self.indirect_blocks = {}
class EXT2_Inode():
def __init__(self, filetype, link_count, direct_blocks = None, indir_block = None, double_indir_block = None, triple_indir_block = None):
self.filetype = filetype
self.link_count = link_count
self.direct_blocks = direct_blocks
self.indir_block = indir_block
self.double_indir_block = double_indir_block
self.triple_indir_block = triple_indir_block
class EXT2_Dirent():
def __init__(self, parent_inode, logical_offset, file_inode, name):
self.parent_inode = parent_inode
self.logical_offset = logical_offset
self.file_inode = file_inode
self.name = name
class EXT2_Indirect_Block():
def __init__(self, parent_inode, depth, logical_offset, block_num, referenced_block_num):
self.parent_inode = parent_inode
self.depth = depth
self.logical_offset = logical_offset
self.block_num = block_num
self.referenced_block_num = referenced_block_num
def print_usage_string(program_name):
print('Usage: {} filename'.format(program_name))
def process_arguments(arguments):
if (len(arguments) != 2):
program_name = arguments[0]
print_usage_string(arguments[0])
sys.exit(Exit_Code.PROGRAM_ERROR.value)
filename = arguments[1]
return filename
def process_ext2_report(filename):
fs_instance = EXT2_Filesystem()
with open(filename, 'r', newline='') as csvfile:
reader = csv.reader(csvfile, delimiter=',', quotechar='\'')
for row in reader:
line_type, *data = row
if (line_type == 'BFREE'):
free_block_num = int(data[0])
fs_instance.free_blocks.append(free_block_num)
elif (line_type == 'IFREE'):
free_inode_num = int(data[0])
fs_instance.free_inodes.append(free_inode_num)
elif (line_type == 'SUPERBLOCK'):
num_of_blocks, num_of_inodes, block_size, inode_size, *_ = data
fs_instance.num_of_blocks = num_of_blocks
fs_instance.num_of_inodes = num_of_inodes
fs_instance.block_size = block_size
fs_instance.inode_size = inode_size
elif (line_type == 'INODE'):
inode_num = data[0]
file_type = data[1]
link_count = data[5]
if (file_type != 's'):
*direct_blocks, indir, d_indir, t_indir = data[11:]
fs_instance.inodes[inode_num] = EXT2_Inode(file_type, link_count, direct_blocks, indir, d_indir, t_indir)
else:
fs_instance.inodes[inode_num] = EXT2_Inode(file_type, link_count)
elif (line_type == 'DIRENT'):
parent_inode, logical_offset, file_inode, _, _, name = data
if (parent_inode not in fs_instance.directories):
fs_instance.directories[parent_inode] = []
fs_instance.directories[parent_inode].append(EXT2_Dirent(parent_inode, logical_offset, file_inode, name))
elif (line_type == 'INDIRECT'):
parent_inode, depth, logical_offset, block_num, ref_block_num = data
if (parent_inode not in fs_instance.indirect_blocks):
fs_instance.indirect_blocks[parent_inode] = []
fs_instance.indirect_blocks[parent_inode].append(EXT2_Indirect_Block(parent_inode, depth, logical_offset, block_num, ref_block_num))
process_inode_allocation_audit(fs_instance)
process_directory_consistency_audit(fs_instance)
def process_inode_allocation_audit(fs_instance):
"""
Checks for I-node allocation inconsistencies.
Prints all inconsistencies to standard output.
"""
inodes_allocation_list = [False] * (int(fs_instance.num_of_inodes) + 1)
# Place free inodes on table
for free_inode in fs_instance.free_inodes:
inodes_allocation_list[free_inode] = True
for inode_number in fs_instance.inodes:
if (inodes_allocation_list[int(inode_number)]):
print('ALLOCATED INODE {0} ON FREELIST'.format(inode_number))
# TODO: inconsistencies found
else:
inodes_allocation_list[int(inode_number)] = True
reserved_inodes = [1, 3, 4, 5, 6, 7, 8, 9, 10]
for inode_number in reserved_inodes:
inodes_allocation_list[inode_number] = True
for index, inode_allocated in enumerate(inodes_allocation_list[1:], 1):
if (not inode_allocated):
print('UNALLOCATED INODE {0} NOT ON FREELIST'.format(index))
# TODO: inconsistencies found
def process_directory_consistency_audit(fs_instance):
"""
Checks for directory inconsistencies.
Prints all inconsistencies to standard output.
"""
reference_counts = {}
for directory in fs_instance.directories.values():
for directory_entry in directory:
file_inode = directory_entry.file_inode
if (file_inode not in reference_counts):
reference_counts[file_inode] = 0
reference_counts[file_inode] = reference_counts[file_inode] + 1
for inode_number in fs_instance.inodes:
link_count = fs_instance.inodes[inode_number].link_count
if (inode_number not in reference_counts):
reference_count = 0
else:
reference_count = reference_counts[inode_number]
if int(link_count) != reference_count:
print('INODE {0} HAS {1} LINKS BUT LINKCOUNT IS {2}'.format(inode_number, reference_count, link_count))
# TODO: inconsistencies found
unallocated_inodes = set()
for inode_number in fs_instance.free_inodes:
unallocated_inodes.add(inode_number)
for inode in fs_instance.inodes:
if (int(inode) in unallocated_inodes):
unallocated_inodes.remove(int(inode))
parent_directories = {}
for directory_inode in fs_instance.directories:
for directory_entry in fs_instance.directories[directory_inode]:
if (directory_entry.name != '..' and directory_entry.name != '.'):
parent_directories[directory_entry.file_inode] = directory_inode
parent_directories['2'] = '2'
for directory_inode in fs_instance.directories:
for directory_entry in fs_instance.directories[directory_inode]:
file_inode = int(directory_entry.file_inode)
if (file_inode < 1 or file_inode > int(fs_instance.num_of_inodes) + 1):
print('DIRECTORY INODE {0} NAME \'{1}\' INVALID INODE {2}'.format(directory_inode, directory_entry.name, file_inode))
# TODO: inconsistencies found
if (file_inode in unallocated_inodes):
print('DIRECTORY INODE {0} NAME \'{1}\' UNALLOCATED INODE {2}'.format(directory_inode, directory_entry.name, file_inode))
# TODO: inconsistencies found
if (directory_entry.name == '.'):
if (int(directory_inode) != file_inode):
print('DIRECTORY INODE {0} NAME \'{1}\' LINK TO INODE {2} SHOULD BE {0}'.format(directory_inode, directory_entry.name, file_inode))
# TODO: inconsistencies found
elif (directory_entry.name == '..'):
parent_inode = int(parent_directories[directory_inode])
if (file_inode != parent_inode):
print('DIRECTORY INODE {0} NAME \'..\' LINK TO INODE {1} SHOULD BE {2}'.format(directory_inode, file_inode, parent_inode))
# TODO: inconsistencies found
if __name__ == '__main__':
filename = process_arguments(sys.argv)
process_ext2_report(filename)