Python：将 /etc/services 文件导入到字典中

Question

所以我必须创建一个 python 脚本来导入

/etc/services

文件并将其写入字典。

目标是端口/协议成为关键并服务于价值。 我希望能够打印输入关键信息的字典并查看服务返回：

print(yourdictionaryname["22/tcp"])
ssh

这个脚本是我能得到的最远的。我在网上找到了它，它工作得很好，但它的设计目的只是显示未使用的端口。似乎无法修改它来执行我需要的操作：

# set the file name depending on the operating system
if sys.platform == 'win32':
file = r'C:\WINDOWS\system32\drivers\etc\services'
else:
file = '/etc/services'

# Create an empty dictionary
ports = dict()

# Iterate through the file, one line at a time
for line in open(file):

# Ignore lines starting with '#' and those containing only whitespace
if line[0:1] != '#' and not line.isspace():

   # Extract the second field (seperated by \s+)
   pp = line.split(None, 1)[1]

   # Extract the port number from port/protocol
   port = pp.split ('/', 1)[0]

   # Convert to int, then store as a dictionary key
   port = int(port)
   ports[port] = None

   # Give up after port 200
   if port > 200: break

# Print any port numbers not present as a dictionary key
for num in xrange(1,201):
if not num in ports:
    print "Unused port", num

Answer 1

根据您想要完成的任务，socket模块可能足以满足您的需求，其

getservbyname

和

getservbyport

功能：

>>> socket.getservbyport(22)
'ssh'
>>> socket.getservbyport(22, 'udp')
'ssh'
>>> socket.getservbyport(22, 'tcp')
'ssh'
>>> socket.getservbyname('http')
80
>>> socket.getservbyname('http', 'tcp')
80
>>> socket.getservbyname('http', 'udp')
80

如果你确实需要字典，你可以用

range(1, 65536)

迭代

getservbyport

。

Answer 2

所以我必须四处寻找才能让它发挥作用。这是一个很酷的功能。首先它检测操作系统，然后根据 /etc/services 文件创建一个字典。接下来，它将解析该文件以获取端口输入，然后返回关联的服务。

import sys
import os

# set the file name depending on the operating system
if sys.platform == 'win32':
    file = os.environ.get('WINDIR', r'C:\WINDOWS') + r'\system32\drivers\etc\services'
else:
    file = '/etc/services'

# Create an empty dictionary
ports = dict()

# Iterate through the file, one line at a time
for line in open(file):

    if line[0:1] != '#' and not line.isspace():
        k = line.split(None, )[1]

        # Extract the port number from port/protocol
        v = line.split('/', )[0]
        j = ''.join([i for i in v if not i.isdigit()])
        l = j.strip('\t')
        ports[k] = l

print(ports.get("22/tcp"))
print(ports.get("8080/tcp"))
print(ports.get("53/udp"))