1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
'''
Utilities for adding or deleting entries on hosts file
as /etc/hosts.
'''
import os
import sys
import json
import subprocess
import socket
import argparse
def is_valid_ip_address(ip):
'''
Check whether an ip address is valid, both for ipv4
and ipv6.
'''
try:
socket.inet_pton(socket.AF_INET, ip)
return True
except socket.error:
pass
try:
socket.inet_pton(socket.AF_INET6, ip)
return True
except socket.error:
pass
return False
def parse_line(line):
pos = line.find("#")
new_line = line[:pos].strip() if pos != -1 else line.strip()
comment = line[pos:] if pos != -1 else ''
if new_line:
parts = list(map(lambda x: x.strip(), new_line.split()))
return (line, parts, comment)
else:
return (line, None, comment)
class HostEditor(object):
def __init__(self, filename='/etc/hosts'):
self.filename = filename
self._parse()
def chk_user_permissions(self):
'''
Check if current user has sufficient permissions to
edit hosts file.
Raise an exception if user is invalid
'''
if self.filename != '-' and not os.access(self.filename, os.W_OK):
msg = 'User does not have sufficient permissions, are you super user?'
raise Exception(msg)
return
def add(self, ip, *hostnames):
'''
Add an entry to hosts file.
'''
self.chk_user_permissions()
if not is_valid_ip_address(ip):
raise Exception("IP %s is not valid." % ip)
if not self.entries:
return
ret = []
added = False
if not self.entries:
return
for (line, parts, comment) in self.entries:
if parts and parts[0] == ip and not added:
for hostname in hostnames:
if hostname not in parts[1:]:
parts.append(hostname)
line = ' '.join(['\t'.join(parts), comment])
added = True
ret.append((line, parts, comment))
if not added:
parts = [ip] + list(hostnames)
line = '\t'.join(parts)
ret.append((line, parts, comment))
self.entries = ret
self.write()
self.output()
def drop(self, ip_or_hostname):
'''
Drop lines with specified ip or hostname from hosts file.
'''
self.chk_user_permissions()
ret = []
for (line, parts, comment) in self.entries:
if parts and ip_or_hostname in parts:
continue
ret.append((line, parts, comment))
self.entries = ret
self.write()
self.output()
def delete(self, ip, hostname):
'''
Delete host from the lines with (ip, hostname) tuple from hosts file.
'''
self.chk_user_permissions()
if not is_valid_ip_address(ip):
raise Exception("IP %s is not valid." % ip)
ret = []
for (line, parts, comment) in self.entries:
if parts and parts[0] == ip:
parts = list(filter(lambda x: x != hostname, parts))
if not parts[1:]:
continue
line = ' '.join(['\t'.join(parts), comment])
ret.append((line, parts, comment))
self.entries = ret
self.write()
self.output()
def _parse(self):
'''
Parse the files into entries.
'''
self.entries = []
fd = sys.stdin if self.filename == '-' else open(self.filename)
for line in fd.readlines():
self.entries.append(parse_line(line))
def output(self, fd=None):
if fd is None:
fd = sys.stdout
fd.write('\n'.join(map(lambda x: x[0].strip(), self.entries)))
fd.write('\n')
def write(self):
if self.filename != '-':
fd = open(self.filename, 'w')
self.output(fd=fd)
fd.close()
def output_docker_ip(self, container):
proc = subprocess.Popen("docker inspect %s" % container,
shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
stdout, stderr = proc.communicate()
if proc.returncode == 0:
ret = json.loads(stdout.decode('utf-8'))
ip = ret[0]['NetworkSettings']['IPAddress']
sys.stdout.write(ip)
def parse_cmdline():
'''
Parse cmd line arguments and returns a dictionary
with its parsed values
'''
parser = argparse.ArgumentParser(
prog='hostsed',
description='A hosts file editing tool for command line shell')
subparsers = parser.add_subparsers(dest='name')
add_parser = subparsers.add_parser(
name='add',
help='Add entry IPADDRESS HOSTNAME1 [HOSTNAME2 ...]'
)
add_parser.add_argument('add',
type=str,
metavar='IPADDRESS_OR_HOSTNAME',
nargs='+')
# subparser does not support aliasing
del_opts = ['del', 'rm', 'delete', 'remove']
for do in del_opts:
del_parser = subparsers.add_parser(
name=do,
help='Delete an IPADDRESS HOSTNAME entry',
)
del_parser.add_argument(do, nargs=2, metavar='IPADDRESS_OR_HOSTNAME',)
drop_parser = subparsers.add_parser(
name='drop',
help='Drop a lines containing an IP_OR_HOSTNAME entry'
)
drop_parser.add_argument('drop', nargs=1, metavar='IPADDRESS_OR_HOSTNAME')
docker_parser = subparsers.add_parser(
name='docker',
help='Show docker cointainer IP address of the given name'
)
docker_parser.add_argument(
'docker',
help='Name of the Container to get IP address from',
metavar='CONTAINER',
type=str,
nargs=1
)
parser.add_argument("-f", "--file",
default="/etc/hosts",
help="The location of hosts file, default /etc/hosts, - for reading from stdin",
type=str)
dparser = vars(parser.parse_args())
# normalize keys for del and its aliases:
name = dparser.get('name')
if name in del_opts:
dparser['name'] = 'del'
dparser['del'] = dparser.get(name)
return dparser
def main():
args = parse_cmdline()
f_name = args.get('name')
he = HostEditor(filename=args.get('file'))
funcs = {
'add': he.add,
'del': he.delete,
'drop': he.drop,
'docker': he.output_docker_ip
}
try:
if not args.get(f_name):
he.output()
else:
funcs.get(f_name)(*args.get(f_name))
except Exception as e:
fd = sys.stdout
fd.write('ERROR: {} \n'.format(e))
if __name__ == '__main__':
main()
|
