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##############################################################################
# Copyright (c) 2015 Todd Gaunt and others.
#
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
##############################################################################
import ipaddress
import logging
import os
class cd:
"""Context manager for changing the current working directory"""
def __init__(self, new_path):
self.new_path = os.path.expanduser(new_path)
def __enter__(self):
self.saved_path = os.getcwd()
os.chdir(self.new_path)
def __exit__(self, etype, value, traceback):
os.chdir(self.saved_path)
def approxsize(x, y, deviation):
"""Approximately compares 'x' to 'y' with in % of 'deviation'"""
logger = logging.getLogger(__name__)
dev = (y * .01 * deviation)
if x >= round(y - dev, 0) and x <= round(y + dev, 0):
logger.debug("{} is approximately {}".format(x, y))
return True
else:
logger.debug("{} is not approximately {}".format(x, y))
return False
def read_line(sock):
"""Reads from a socket until a \n character or 512 bytes have been read,
whichever comes first"""
c = ""
recvline = ""
reads = 0
while (c != "\n" and reads < 512):
# Decode bytes to str, sockets output bytes which aren't pretty
c = sock.recv(1).decode("utf-8")
#print("char: '" + c + "'") # Debugging code
recvline += c
reads += 1
return recvline
def read_msg(sock):
"""Reads a message prefixed with a number and a newline char, eg. "20\n"
then reads x lines, where x is equal to the number in the first line."""
# Read the socket once initially for the line count
buf = read_line(sock)
buf = buf[:-1] # Cut off the '\n' character
length = int(buf)
lines = []
for i in range(length):
lines.append(read_line(sock))
return "".join(lines)
def send_msg(sock, msg):
"""Sends a message to a socket"""
# Encode python str to bytes beforehand, sockets only deal in bytes
msg = bytes(msg, "utf-8")
totalsent = 0
while totalsent < len(msg):
sent = sock.send(msg[totalsent:])
if sent == 0:
return -1
totalsent = totalsent + sent
return totalsent
def get_addr(interface):
"""Get the address of the machine that this program is running on"""
return netifaces.ifaddresses(interface)[netifaces.AF_INET][0]["addr"]
def gen_ip_range(cidr, excluded, minimum, maximum ):
"""Takes a network cidr number, and then a min max value, and creates a list
of ip addresses avalable on [a,b]. Also removes "excluded" addresses
from the range"""
logger = logging.getLogger(__name__)
# Generate a list of available ip addresses for the dhcp server
ip_range = list(map(lambda x: x.exploded, ipaddress.ip_network(cidr).hosts()))
for addr in excluded:
# Remove the value from the list, if it isn't in the list then whatever
try:
ip_range.remove(addr)
except ValueError:
logger.debug("{} not in ip_range, cannot remove".format(addr))
# Remove all values before the minimum usable value
for i in range(len(ip_range)):
if ip_range[i] == minimum:
ip_range = ip_range[i::]
break
# Remove all values after the maximum usable value
for i in range(len(ip_range)):
if ip_range[i] == maximum:
ip_range = ip_range[0:i+1]
break
return ip_range
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