Print files that have a specific length ACL text presentation

acllength.py

#!/usr/bin/python

"""Print files that have a specific length ACL text presentation

Used to debug a backup tool that may have been having problems with files
with this precise ACL representation.

Created by Jesse Peterson on 2/2/16
"""

import sys
import os
from ctypes import *
from ctypes.util import find_library

libc = cdll.LoadLibrary(find_library('c'))

# from <sys/acl.h>
ACL_TYPE_EXTENDED = 0x00000100

acl_get_file = libc.acl_get_file
acl_get_file.argtypes = [c_char_p, c_int]
acl_get_file.restype = c_void_p

acl_to_text = libc.acl_to_text
# note the second ulong here is actually a pointer,
# havn't looked into how to provide a ptr arg yet
acl_to_text.argtypes = [c_void_p, c_ulong]
acl_to_text.restype = c_char_p

acl_free = libc.acl_free
acl_free.argtypes = [c_void_p]
acl_free.restype = c_int

for stdinline in sys.stdin:
	if stdinline[-1] == '\n':
		filename = stdinline[:-1]

	if os.path.exists(filename):
		acl = acl_get_file(filename, ACL_TYPE_EXTENDED)
		if acl:
			textacl = acl_to_text(acl, 0)

			modded = len(textacl) % 1024

			if modded <= 5 or modded >= 1018:
				print len(textacl), modded, filename

			acl_free(acl)