1 | """CGI-savvy HTTP Server.
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2 |
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3 | This module builds on SimpleHTTPServer by implementing GET and POST
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4 | requests to cgi-bin scripts.
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5 |
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6 | If the os.fork() function is not present (e.g. on Windows),
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7 | os.popen2() is used as a fallback, with slightly altered semantics; if
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8 | that function is not present either (e.g. on Macintosh), only Python
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9 | scripts are supported, and they are executed by the current process.
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10 |
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11 | In all cases, the implementation is intentionally naive -- all
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12 | requests are executed sychronously.
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13 |
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14 | SECURITY WARNING: DON'T USE THIS CODE UNLESS YOU ARE INSIDE A FIREWALL
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15 | -- it may execute arbitrary Python code or external programs.
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16 |
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17 | Note that status code 200 is sent prior to execution of a CGI script, so
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18 | scripts cannot send other status codes such as 302 (redirect).
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19 | """
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20 |
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21 |
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22 | __version__ = "0.4"
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23 |
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24 | __all__ = ["CGIHTTPRequestHandler"]
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25 |
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26 | import os
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27 | import sys
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28 | import urllib
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29 | import BaseHTTPServer
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30 | import SimpleHTTPServer
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31 | import select
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32 |
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33 |
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34 | class CGIHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
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35 |
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36 | """Complete HTTP server with GET, HEAD and POST commands.
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37 |
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38 | GET and HEAD also support running CGI scripts.
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39 |
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40 | The POST command is *only* implemented for CGI scripts.
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41 |
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42 | """
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43 |
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44 | # Determine platform specifics
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45 | have_fork = hasattr(os, 'fork')
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46 | have_popen2 = hasattr(os, 'popen2')
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47 | have_popen3 = hasattr(os, 'popen3')
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48 |
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49 | # Make rfile unbuffered -- we need to read one line and then pass
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50 | # the rest to a subprocess, so we can't use buffered input.
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51 | rbufsize = 0
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52 |
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53 | def do_POST(self):
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54 | """Serve a POST request.
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55 |
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56 | This is only implemented for CGI scripts.
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57 |
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58 | """
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59 |
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60 | if self.is_cgi():
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61 | self.run_cgi()
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62 | else:
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63 | self.send_error(501, "Can only POST to CGI scripts")
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64 |
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65 | def send_head(self):
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66 | """Version of send_head that support CGI scripts"""
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67 | if self.is_cgi():
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68 | return self.run_cgi()
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69 | else:
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70 | return SimpleHTTPServer.SimpleHTTPRequestHandler.send_head(self)
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71 |
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72 | def is_cgi(self):
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73 | """Test whether self.path corresponds to a CGI script,
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74 | and return a boolean.
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75 |
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76 | This function sets self.cgi_info to a tuple (dir, rest)
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77 | when it returns True, where dir is the directory part before
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78 | the CGI script name. Note that rest begins with a
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79 | slash if it is not empty.
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80 |
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81 | The default implementation tests whether the path
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82 | begins with one of the strings in the list
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83 | self.cgi_directories (and the next character is a '/'
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84 | or the end of the string).
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85 | """
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86 |
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87 | path = self.path
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88 |
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89 | for x in self.cgi_directories:
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90 | i = len(x)
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91 | if path[:i] == x and (not path[i:] or path[i] == '/'):
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92 | self.cgi_info = path[:i], path[i+1:]
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93 | return True
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94 | return False
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95 |
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96 | cgi_directories = ['/cgi-bin', '/htbin']
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97 |
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98 | def is_executable(self, path):
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99 | """Test whether argument path is an executable file."""
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100 | return executable(path)
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101 |
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102 | def is_python(self, path):
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103 | """Test whether argument path is a Python script."""
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104 | head, tail = os.path.splitext(path)
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105 | return tail.lower() in (".py", ".pyw")
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106 |
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107 | def run_cgi(self):
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108 | """Execute a CGI script."""
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109 | path = self.path
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110 | dir, rest = self.cgi_info
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111 |
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112 | i = path.find('/', len(dir) + 1)
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113 | while i >= 0:
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114 | nextdir = path[:i]
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115 | nextrest = path[i+1:]
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116 |
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117 | scriptdir = self.translate_path(nextdir)
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118 | if os.path.isdir(scriptdir):
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119 | dir, rest = nextdir, nextrest
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120 | i = path.find('/', len(dir) + 1)
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121 | else:
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122 | break
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123 |
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124 | # find an explicit query string, if present.
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125 | i = rest.rfind('?')
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126 | if i >= 0:
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127 | rest, query = rest[:i], rest[i+1:]
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128 | else:
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129 | query = ''
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130 |
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131 | # dissect the part after the directory name into a script name &
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132 | # a possible additional path, to be stored in PATH_INFO.
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133 | i = rest.find('/')
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134 | if i >= 0:
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135 | script, rest = rest[:i], rest[i:]
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136 | else:
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137 | script, rest = rest, ''
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138 |
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139 | scriptname = dir + '/' + script
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140 | scriptfile = self.translate_path(scriptname)
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141 | if not os.path.exists(scriptfile):
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142 | self.send_error(404, "No such CGI script (%r)" % scriptname)
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143 | return
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144 | if not os.path.isfile(scriptfile):
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145 | self.send_error(403, "CGI script is not a plain file (%r)" %
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146 | scriptname)
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147 | return
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148 | ispy = self.is_python(scriptname)
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149 | if not ispy:
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150 | if not (self.have_fork or self.have_popen2 or self.have_popen3):
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151 | self.send_error(403, "CGI script is not a Python script (%r)" %
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152 | scriptname)
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153 | return
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154 | if not self.is_executable(scriptfile):
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155 | self.send_error(403, "CGI script is not executable (%r)" %
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156 | scriptname)
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157 | return
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158 |
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159 | # Reference: http://hoohoo.ncsa.uiuc.edu/cgi/env.html
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160 | # XXX Much of the following could be prepared ahead of time!
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161 | env = {}
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162 | env['SERVER_SOFTWARE'] = self.version_string()
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163 | env['SERVER_NAME'] = self.server.server_name
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164 | env['GATEWAY_INTERFACE'] = 'CGI/1.1'
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165 | env['SERVER_PROTOCOL'] = self.protocol_version
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166 | env['SERVER_PORT'] = str(self.server.server_port)
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167 | env['REQUEST_METHOD'] = self.command
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168 | uqrest = urllib.unquote(rest)
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169 | env['PATH_INFO'] = uqrest
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170 | env['PATH_TRANSLATED'] = self.translate_path(uqrest)
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171 | env['SCRIPT_NAME'] = scriptname
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172 | if query:
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173 | env['QUERY_STRING'] = query
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174 | host = self.address_string()
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175 | if host != self.client_address[0]:
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176 | env['REMOTE_HOST'] = host
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177 | env['REMOTE_ADDR'] = self.client_address[0]
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178 | authorization = self.headers.getheader("authorization")
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179 | if authorization:
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180 | authorization = authorization.split()
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181 | if len(authorization) == 2:
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182 | import base64, binascii
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183 | env['AUTH_TYPE'] = authorization[0]
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184 | if authorization[0].lower() == "basic":
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185 | try:
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186 | authorization = base64.decodestring(authorization[1])
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187 | except binascii.Error:
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188 | pass
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189 | else:
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190 | authorization = authorization.split(':')
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191 | if len(authorization) == 2:
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192 | env['REMOTE_USER'] = authorization[0]
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193 | # XXX REMOTE_IDENT
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194 | if self.headers.typeheader is None:
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195 | env['CONTENT_TYPE'] = self.headers.type
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196 | else:
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197 | env['CONTENT_TYPE'] = self.headers.typeheader
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198 | length = self.headers.getheader('content-length')
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199 | if length:
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200 | env['CONTENT_LENGTH'] = length
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201 | referer = self.headers.getheader('referer')
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202 | if referer:
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203 | env['HTTP_REFERER'] = referer
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204 | accept = []
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205 | for line in self.headers.getallmatchingheaders('accept'):
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206 | if line[:1] in "\t\n\r ":
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207 | accept.append(line.strip())
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208 | else:
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209 | accept = accept + line[7:].split(',')
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210 | env['HTTP_ACCEPT'] = ','.join(accept)
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211 | ua = self.headers.getheader('user-agent')
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212 | if ua:
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213 | env['HTTP_USER_AGENT'] = ua
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214 | co = filter(None, self.headers.getheaders('cookie'))
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215 | if co:
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216 | env['HTTP_COOKIE'] = ', '.join(co)
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217 | # XXX Other HTTP_* headers
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218 | # Since we're setting the env in the parent, provide empty
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219 | # values to override previously set values
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220 | for k in ('QUERY_STRING', 'REMOTE_HOST', 'CONTENT_LENGTH',
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221 | 'HTTP_USER_AGENT', 'HTTP_COOKIE', 'HTTP_REFERER'):
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222 | env.setdefault(k, "")
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223 | os.environ.update(env)
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224 |
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225 | self.send_response(200, "Script output follows")
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226 |
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227 | decoded_query = query.replace('+', ' ')
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228 |
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229 | if self.have_fork:
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230 | # Unix -- fork as we should
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231 | args = [script]
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232 | if '=' not in decoded_query:
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233 | args.append(decoded_query)
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234 | nobody = nobody_uid()
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235 | self.wfile.flush() # Always flush before forking
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236 | pid = os.fork()
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237 | if pid != 0:
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238 | # Parent
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239 | pid, sts = os.waitpid(pid, 0)
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240 | # throw away additional data [see bug #427345]
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241 | while select.select([self.rfile], [], [], 0)[0]:
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242 | if not self.rfile.read(1):
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243 | break
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244 | if sts:
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245 | self.log_error("CGI script exit status %#x", sts)
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246 | return
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247 | # Child
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248 | try:
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249 | try:
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250 | os.setuid(nobody)
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251 | except os.error:
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252 | pass
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253 | os.dup2(self.rfile.fileno(), 0)
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254 | os.dup2(self.wfile.fileno(), 1)
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255 | os.execve(scriptfile, args, os.environ)
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256 | except:
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257 | self.server.handle_error(self.request, self.client_address)
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258 | os._exit(127)
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259 |
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260 | else:
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261 | # Non Unix - use subprocess
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262 | import subprocess
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263 | cmdline = [scriptfile]
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264 | if self.is_python(scriptfile):
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265 | interp = sys.executable
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266 | if interp.lower().endswith("w.exe"):
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267 | # On Windows, use python.exe, not pythonw.exe
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268 | interp = interp[:-5] + interp[-4:]
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269 | cmdline = [interp, '-u'] + cmdline
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270 | if '=' not in query:
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271 | cmdline.append(query)
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272 |
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273 | self.log_message("command: %s", subprocess.list2cmdline(cmdline))
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274 | try:
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275 | nbytes = int(length)
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276 | except (TypeError, ValueError):
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277 | nbytes = 0
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278 | p = subprocess.Popen(cmdline,
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279 | stdin = subprocess.PIPE,
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280 | stdout = subprocess.PIPE,
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281 | stderr = subprocess.PIPE
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282 | )
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283 | if self.command.lower() == "post" and nbytes > 0:
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284 | data = self.rfile.read(nbytes)
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285 | else:
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286 | data = None
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287 | # throw away additional data [see bug #427345]
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288 | while select.select([self.rfile._sock], [], [], 0)[0]:
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289 | if not self.rfile._sock.recv(1):
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290 | break
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291 | stdout, stderr = p.communicate(data)
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292 | self.wfile.write(stdout)
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293 | if stderr:
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294 | self.log_error('%s', stderr)
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295 | status = p.returncode
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296 | if status:
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297 | self.log_error("CGI script exit status %#x", status)
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298 | else:
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299 | self.log_message("CGI script exited OK")
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300 |
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301 |
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302 | nobody = None
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303 |
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304 | def nobody_uid():
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305 | """Internal routine to get nobody's uid"""
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306 | global nobody
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307 | if nobody:
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308 | return nobody
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309 | try:
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310 | import pwd
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311 | except ImportError:
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312 | return -1
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313 | try:
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314 | nobody = pwd.getpwnam('nobody')[2]
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315 | except KeyError:
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316 | nobody = 1 + max(map(lambda x: x[2], pwd.getpwall()))
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317 | return nobody
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318 |
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319 |
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320 | def executable(path):
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321 | """Test for executable file."""
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322 | try:
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323 | st = os.stat(path)
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324 | except os.error:
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325 | return False
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326 | return st.st_mode & 0111 != 0
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327 |
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328 |
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329 | def test(HandlerClass = CGIHTTPRequestHandler,
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330 | ServerClass = BaseHTTPServer.HTTPServer):
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331 | SimpleHTTPServer.test(HandlerClass, ServerClass)
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332 |
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333 |
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334 | if __name__ == '__main__':
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335 | test()
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