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#
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#
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4 db4e138b Manuel Franceschini
# Copyright (C) 2007, 2008, 2010 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""HTTP server module.
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"""
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import BaseHTTPServer
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import cgi
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import logging
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import os
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import socket
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import time
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import signal
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import asyncore
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from ganeti import http
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from ganeti import utils
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from ganeti import netutils
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from ganeti import compat
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from ganeti import errors
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WEEKDAYNAME = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
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MONTHNAME = [None,
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             "Jan", "Feb", "Mar", "Apr", "May", "Jun",
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             "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
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# Default error message
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DEFAULT_ERROR_CONTENT_TYPE = "text/html"
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DEFAULT_ERROR_MESSAGE = """\
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<html>
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<head>
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<title>Error response</title>
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</head>
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<body>
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<h1>Error response</h1>
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<p>Error code %(code)d.
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<p>Message: %(message)s.
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<p>Error code explanation: %(code)s = %(explain)s.
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</body>
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</html>
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"""
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def _DateTimeHeader(gmnow=None):
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  """Return the current date and time formatted for a message header.
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  The time MUST be in the GMT timezone.
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  """
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  if gmnow is None:
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    gmnow = time.gmtime()
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  (year, month, day, hh, mm, ss, wd, _, _) = gmnow
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  return ("%s, %02d %3s %4d %02d:%02d:%02d GMT" %
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          (WEEKDAYNAME[wd], day, MONTHNAME[month], year, hh, mm, ss))
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class _HttpServerRequest(object):
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  """Data structure for HTTP request on server side.
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  """
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  def __init__(self, method, path, headers, body):
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    # Request attributes
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    self.request_method = method
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    self.request_path = path
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    self.request_headers = headers
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    self.request_body = body
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    # Response attributes
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    self.resp_headers = {}
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    # Private data for request handler (useful in combination with
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    # authentication)
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    self.private = None
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  def __repr__(self):
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    status = ["%s.%s" % (self.__class__.__module__, self.__class__.__name__),
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              self.request_method, self.request_path,
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              "headers=%r" % str(self.request_headers),
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              "body=%r" % (self.request_body, )]
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    return "<%s at %#x>" % (" ".join(status), id(self))
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class _HttpServerToClientMessageWriter(http.HttpMessageWriter):
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  """Writes an HTTP response to client.
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  """
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  def __init__(self, sock, request_msg, response_msg, write_timeout):
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    """Writes the response to the client.
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    @type sock: socket
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    @param sock: Target socket
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    @type request_msg: http.HttpMessage
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    @param request_msg: Request message, required to determine whether
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        response may have a message body
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    @type response_msg: http.HttpMessage
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    @param response_msg: Response message
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    @type write_timeout: float
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    @param write_timeout: Write timeout for socket
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    """
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    self._request_msg = request_msg
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    self._response_msg = response_msg
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    http.HttpMessageWriter.__init__(self, sock, response_msg, write_timeout)
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  def HasMessageBody(self):
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    """Logic to detect whether response should contain a message body.
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    """
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    if self._request_msg.start_line:
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      request_method = self._request_msg.start_line.method
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    else:
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      request_method = None
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    response_code = self._response_msg.start_line.code
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    # RFC2616, section 4.3: "A message-body MUST NOT be included in a request
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    # if the specification of the request method (section 5.1.1) does not allow
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    # sending an entity-body in requests"
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    #
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    # RFC2616, section 9.4: "The HEAD method is identical to GET except that
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    # the server MUST NOT return a message-body in the response."
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    #
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    # RFC2616, section 10.2.5: "The 204 response MUST NOT include a
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    # message-body [...]"
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    #
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    # RFC2616, section 10.3.5: "The 304 response MUST NOT contain a
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    # message-body, [...]"
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    return (http.HttpMessageWriter.HasMessageBody(self) and
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            (request_method is not None and
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             request_method != http.HTTP_HEAD) and
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            response_code >= http.HTTP_OK and
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            response_code not in (http.HTTP_NO_CONTENT,
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                                  http.HTTP_NOT_MODIFIED))
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class _HttpClientToServerMessageReader(http.HttpMessageReader):
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  """Reads an HTTP request sent by client.
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  """
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  # Length limits
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  START_LINE_LENGTH_MAX = 4096
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  HEADER_LENGTH_MAX = 4096
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  def ParseStartLine(self, start_line):
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    """Parses the start line sent by client.
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    Example: "GET /index.html HTTP/1.1"
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    @type start_line: string
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    @param start_line: Start line
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    """
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    # Empty lines are skipped when reading
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    assert start_line
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    logging.debug("HTTP request: %s", start_line)
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    words = start_line.split()
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    if len(words) == 3:
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      [method, path, version] = words
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      if version[:5] != "HTTP/":
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        raise http.HttpBadRequest("Bad request version (%r)" % version)
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      try:
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        base_version_number = version.split("/", 1)[1]
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        version_number = base_version_number.split(".")
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        # RFC 2145 section 3.1 says there can be only one "." and
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        #   - major and minor numbers MUST be treated as
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        #      separate integers;
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        #   - HTTP/2.4 is a lower version than HTTP/2.13, which in
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        #      turn is lower than HTTP/12.3;
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        #   - Leading zeros MUST be ignored by recipients.
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        if len(version_number) != 2:
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          raise http.HttpBadRequest("Bad request version (%r)" % version)
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        version_number = (int(version_number[0]), int(version_number[1]))
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      except (ValueError, IndexError):
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        raise http.HttpBadRequest("Bad request version (%r)" % version)
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      if version_number >= (2, 0):
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        raise http.HttpVersionNotSupported("Invalid HTTP Version (%s)" %
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                                      base_version_number)
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    elif len(words) == 2:
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      version = http.HTTP_0_9
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      [method, path] = words
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      if method != http.HTTP_GET:
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        raise http.HttpBadRequest("Bad HTTP/0.9 request type (%r)" % method)
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    else:
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      raise http.HttpBadRequest("Bad request syntax (%r)" % start_line)
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    return http.HttpClientToServerStartLine(method, path, version)
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def _HandleServerRequestInner(handler, req_msg):
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  """Calls the handler function for the current request.
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  """
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  handler_context = _HttpServerRequest(req_msg.start_line.method,
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                                       req_msg.start_line.path,
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                                       req_msg.headers,
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                                       req_msg.body)
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  logging.debug("Handling request %r", handler_context)
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  try:
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    try:
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      # Authentication, etc.
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      handler.PreHandleRequest(handler_context)
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      # Call actual request handler
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      result = handler.HandleRequest(handler_context)
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    except (http.HttpException, errors.RapiTestResult,
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            KeyboardInterrupt, SystemExit):
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      raise
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    except Exception, err:
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      logging.exception("Caught exception")
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      raise http.HttpInternalServerError(message=str(err))
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    except:
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      logging.exception("Unknown exception")
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      raise http.HttpInternalServerError(message="Unknown error")
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    if not isinstance(result, basestring):
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      raise http.HttpError("Handler function didn't return string type")
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    return (http.HTTP_OK, handler_context.resp_headers, result)
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  finally:
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    # No reason to keep this any longer, even for exceptions
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    handler_context.private = None
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class HttpResponder(object):
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  # The default request version.  This only affects responses up until
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  # the point where the request line is parsed, so it mainly decides what
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  # the client gets back when sending a malformed request line.
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  # Most web servers default to HTTP 0.9, i.e. don't send a status line.
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  default_request_version = http.HTTP_0_9
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  responses = BaseHTTPServer.BaseHTTPRequestHandler.responses
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  def __init__(self, handler):
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    """Initializes this class.
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    """
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    self._handler = handler
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  def __call__(self, fn):
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    """Handles a request.
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    @type fn: callable
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    @param fn: Callback for retrieving HTTP request, must return a tuple
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      containing request message (L{http.HttpMessage}) and C{None} or the
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      message reader (L{_HttpClientToServerMessageReader})
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    """
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    response_msg = http.HttpMessage()
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    response_msg.start_line = \
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      http.HttpServerToClientStartLine(version=self.default_request_version,
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                                       code=None, reason=None)
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    force_close = True
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    try:
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      (request_msg, req_msg_reader) = fn()
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      response_msg.start_line.version = request_msg.start_line.version
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      # RFC2616, 14.23: All Internet-based HTTP/1.1 servers MUST respond
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      # with a 400 (Bad Request) status code to any HTTP/1.1 request
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      # message which lacks a Host header field.
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      if (request_msg.start_line.version == http.HTTP_1_1 and
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          not (request_msg.headers and
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               http.HTTP_HOST in request_msg.headers)):
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        raise http.HttpBadRequest(message="Missing Host header")
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      (response_msg.start_line.code, response_msg.headers,
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       response_msg.body) = \
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        _HandleServerRequestInner(self._handler, request_msg)
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    except http.HttpException, err:
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      self._SetError(self.responses, self._handler, response_msg, err)
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    else:
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      # Only wait for client to close if we didn't have any exception.
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      force_close = False
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    return (request_msg, req_msg_reader, force_close,
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            self._Finalize(self.responses, response_msg))
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  @staticmethod
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  def _SetError(responses, handler, response_msg, err):
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    """Sets the response code and body from a HttpException.
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    @type err: HttpException
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    @param err: Exception instance
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    """
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    try:
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      (shortmsg, longmsg) = responses[err.code]
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    except KeyError:
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      shortmsg = longmsg = "Unknown"
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    if err.message:
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      message = err.message
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    else:
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      message = shortmsg
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    values = {
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      "code": err.code,
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      "message": cgi.escape(message),
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      "explain": longmsg,
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      }
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    (content_type, body) = handler.FormatErrorMessage(values)
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    headers = {
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      http.HTTP_CONTENT_TYPE: content_type,
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      }
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    if err.headers:
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      headers.update(err.headers)
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    response_msg.start_line.code = err.code
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    response_msg.headers = headers
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    response_msg.body = body
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  @staticmethod
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  def _Finalize(responses, msg):
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    assert msg.start_line.reason is None
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    if not msg.headers:
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      msg.headers = {}
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    msg.headers.update({
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      # TODO: Keep-alive is not supported
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      http.HTTP_CONNECTION: "close",
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      http.HTTP_DATE: _DateTimeHeader(),
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      http.HTTP_SERVER: http.HTTP_GANETI_VERSION,
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      })
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    # Get response reason based on code
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    try:
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      code_desc = responses[msg.start_line.code]
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    except KeyError:
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      reason = ""
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    else:
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      (reason, _) = code_desc
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371 d859a2cf Michael Hanselmann
    msg.start_line.reason = reason
372 d859a2cf Michael Hanselmann
373 d859a2cf Michael Hanselmann
    return msg
374 d859a2cf Michael Hanselmann
375 d859a2cf Michael Hanselmann
376 1f8588f6 Iustin Pop
class HttpServerRequestExecutor(object):
377 02cab3e7 Michael Hanselmann
  """Implements server side of HTTP.
378 02cab3e7 Michael Hanselmann

379 25e7b43f Iustin Pop
  This class implements the server side of HTTP. It's based on code of
380 25e7b43f Iustin Pop
  Python's BaseHTTPServer, from both version 2.4 and 3k. It does not
381 25e7b43f Iustin Pop
  support non-ASCII character encodings. Keep-alive connections are
382 25e7b43f Iustin Pop
  not supported.
383 02cab3e7 Michael Hanselmann

384 02cab3e7 Michael Hanselmann
  """
385 02cab3e7 Michael Hanselmann
  # Timeouts in seconds for socket layer
386 02cab3e7 Michael Hanselmann
  WRITE_TIMEOUT = 10
387 02cab3e7 Michael Hanselmann
  READ_TIMEOUT = 10
388 02cab3e7 Michael Hanselmann
  CLOSE_TIMEOUT = 1
389 02cab3e7 Michael Hanselmann
390 e0003509 Michael Hanselmann
  def __init__(self, server, handler, sock, client_addr):
391 02cab3e7 Michael Hanselmann
    """Initializes this class.
392 02cab3e7 Michael Hanselmann

393 02cab3e7 Michael Hanselmann
    """
394 d859a2cf Michael Hanselmann
    responder = HttpResponder(handler)
395 02cab3e7 Michael Hanselmann
396 02cab3e7 Michael Hanselmann
    # Disable Python's timeout
397 d859a2cf Michael Hanselmann
    sock.settimeout(None)
398 02cab3e7 Michael Hanselmann
399 02cab3e7 Michael Hanselmann
    # Operate in non-blocking mode
400 d859a2cf Michael Hanselmann
    sock.setblocking(0)
401 d859a2cf Michael Hanselmann
402 d859a2cf Michael Hanselmann
    request_msg_reader = None
403 d859a2cf Michael Hanselmann
    force_close = True
404 02cab3e7 Michael Hanselmann
405 14d57a8b Iustin Pop
    logging.debug("Connection from %s:%s", client_addr[0], client_addr[1])
406 02cab3e7 Michael Hanselmann
    try:
407 d859a2cf Michael Hanselmann
      # Block for closing connection
408 02cab3e7 Michael Hanselmann
      try:
409 f2e13d55 Michael Hanselmann
        # Do the secret SSL handshake
410 d859a2cf Michael Hanselmann
        if server.using_ssl:
411 d859a2cf Michael Hanselmann
          sock.set_accept_state()
412 f2e13d55 Michael Hanselmann
          try:
413 d859a2cf Michael Hanselmann
            http.Handshake(sock, self.WRITE_TIMEOUT)
414 f2e13d55 Michael Hanselmann
          except http.HttpSessionHandshakeUnexpectedEOF:
415 f2e13d55 Michael Hanselmann
            # Ignore rest
416 f2e13d55 Michael Hanselmann
            return
417 f2e13d55 Michael Hanselmann
418 d859a2cf Michael Hanselmann
        (request_msg, request_msg_reader, force_close, response_msg) = \
419 d859a2cf Michael Hanselmann
          responder(compat.partial(self._ReadRequest, sock, self.READ_TIMEOUT))
420 d859a2cf Michael Hanselmann
        if response_msg:
421 d859a2cf Michael Hanselmann
          # HttpMessage.start_line can be of different types
422 d859a2cf Michael Hanselmann
          # pylint: disable=E1103
423 d859a2cf Michael Hanselmann
          logging.info("%s:%s %s %s", client_addr[0], client_addr[1],
424 d859a2cf Michael Hanselmann
                       request_msg.start_line, response_msg.start_line.code)
425 d859a2cf Michael Hanselmann
          self._SendResponse(sock, request_msg, response_msg,
426 d859a2cf Michael Hanselmann
                             self.WRITE_TIMEOUT)
427 02cab3e7 Michael Hanselmann
      finally:
428 aea0ed67 Michael Hanselmann
        http.ShutdownConnection(sock, self.CLOSE_TIMEOUT, self.WRITE_TIMEOUT,
429 02cab3e7 Michael Hanselmann
                                request_msg_reader, force_close)
430 02cab3e7 Michael Hanselmann
431 d859a2cf Michael Hanselmann
      sock.close()
432 02cab3e7 Michael Hanselmann
    finally:
433 14d57a8b Iustin Pop
      logging.debug("Disconnected %s:%s", client_addr[0], client_addr[1])
434 02cab3e7 Michael Hanselmann
435 d859a2cf Michael Hanselmann
  @staticmethod
436 d859a2cf Michael Hanselmann
  def _ReadRequest(sock, timeout):
437 02cab3e7 Michael Hanselmann
    """Reads a request sent by client.
438 02cab3e7 Michael Hanselmann

439 02cab3e7 Michael Hanselmann
    """
440 d859a2cf Michael Hanselmann
    msg = http.HttpMessage()
441 d859a2cf Michael Hanselmann
442 02cab3e7 Michael Hanselmann
    try:
443 d859a2cf Michael Hanselmann
      reader = _HttpClientToServerMessageReader(sock, msg, timeout)
444 02cab3e7 Michael Hanselmann
    except http.HttpSocketTimeout:
445 02cab3e7 Michael Hanselmann
      raise http.HttpError("Timeout while reading request")
446 02cab3e7 Michael Hanselmann
    except socket.error, err:
447 02cab3e7 Michael Hanselmann
      raise http.HttpError("Error reading request: %s" % err)
448 02cab3e7 Michael Hanselmann
449 d859a2cf Michael Hanselmann
    return (msg, reader)
450 02cab3e7 Michael Hanselmann
451 d859a2cf Michael Hanselmann
  @staticmethod
452 d859a2cf Michael Hanselmann
  def _SendResponse(sock, req_msg, msg, timeout):
453 02cab3e7 Michael Hanselmann
    """Sends the response to the client.
454 02cab3e7 Michael Hanselmann

455 02cab3e7 Michael Hanselmann
    """
456 02cab3e7 Michael Hanselmann
    try:
457 d859a2cf Michael Hanselmann
      _HttpServerToClientMessageWriter(sock, req_msg, msg, timeout)
458 02cab3e7 Michael Hanselmann
    except http.HttpSocketTimeout:
459 02cab3e7 Michael Hanselmann
      raise http.HttpError("Timeout while sending response")
460 02cab3e7 Michael Hanselmann
    except socket.error, err:
461 02cab3e7 Michael Hanselmann
      raise http.HttpError("Error sending response: %s" % err)
462 02cab3e7 Michael Hanselmann
463 57fd6d0b Michael Hanselmann
464 112d240d Guido Trotter
class HttpServer(http.HttpBase, asyncore.dispatcher):
465 02cab3e7 Michael Hanselmann
  """Generic HTTP server class
466 02cab3e7 Michael Hanselmann

467 02cab3e7 Michael Hanselmann
  """
468 02cab3e7 Michael Hanselmann
  MAX_CHILDREN = 20
469 02cab3e7 Michael Hanselmann
470 e0003509 Michael Hanselmann
  def __init__(self, mainloop, local_address, port, handler,
471 1f8588f6 Iustin Pop
               ssl_params=None, ssl_verify_peer=False,
472 1f8588f6 Iustin Pop
               request_executor_class=None):
473 02cab3e7 Michael Hanselmann
    """Initializes the HTTP server
474 02cab3e7 Michael Hanselmann

475 02cab3e7 Michael Hanselmann
    @type mainloop: ganeti.daemon.Mainloop
476 02cab3e7 Michael Hanselmann
    @param mainloop: Mainloop used to poll for I/O events
477 c41eea6e Iustin Pop
    @type local_address: string
478 02cab3e7 Michael Hanselmann
    @param local_address: Local IP address to bind to
479 02cab3e7 Michael Hanselmann
    @type port: int
480 02cab3e7 Michael Hanselmann
    @param port: TCP port to listen on
481 02cab3e7 Michael Hanselmann
    @type ssl_params: HttpSslParams
482 02cab3e7 Michael Hanselmann
    @param ssl_params: SSL key and certificate
483 02cab3e7 Michael Hanselmann
    @type ssl_verify_peer: bool
484 25e7b43f Iustin Pop
    @param ssl_verify_peer: Whether to require client certificate
485 25e7b43f Iustin Pop
        and compare it with our certificate
486 1f8588f6 Iustin Pop
    @type request_executor_class: class
487 1f8588f6 Iustin Pop
    @param request_executor_class: an class derived from the
488 1f8588f6 Iustin Pop
        HttpServerRequestExecutor class
489 02cab3e7 Michael Hanselmann

490 02cab3e7 Michael Hanselmann
    """
491 f4322a1e Michael Hanselmann
    http.HttpBase.__init__(self)
492 112d240d Guido Trotter
    asyncore.dispatcher.__init__(self)
493 02cab3e7 Michael Hanselmann
494 1f8588f6 Iustin Pop
    if request_executor_class is None:
495 1f8588f6 Iustin Pop
      self.request_executor = HttpServerRequestExecutor
496 1f8588f6 Iustin Pop
    else:
497 1f8588f6 Iustin Pop
      self.request_executor = request_executor_class
498 1f8588f6 Iustin Pop
499 02cab3e7 Michael Hanselmann
    self.mainloop = mainloop
500 02cab3e7 Michael Hanselmann
    self.local_address = local_address
501 02cab3e7 Michael Hanselmann
    self.port = port
502 e0003509 Michael Hanselmann
    self.handler = handler
503 db4e138b Manuel Franceschini
    family = netutils.IPAddress.GetAddressFamily(local_address)
504 db4e138b Manuel Franceschini
    self.socket = self._CreateSocket(ssl_params, ssl_verify_peer, family)
505 02cab3e7 Michael Hanselmann
506 02cab3e7 Michael Hanselmann
    # Allow port to be reused
507 02cab3e7 Michael Hanselmann
    self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
508 02cab3e7 Michael Hanselmann
509 02cab3e7 Michael Hanselmann
    self._children = []
510 112d240d Guido Trotter
    self.set_socket(self.socket)
511 112d240d Guido Trotter
    self.accepting = True
512 02cab3e7 Michael Hanselmann
    mainloop.RegisterSignal(self)
513 02cab3e7 Michael Hanselmann
514 02cab3e7 Michael Hanselmann
  def Start(self):
515 02cab3e7 Michael Hanselmann
    self.socket.bind((self.local_address, self.port))
516 59305197 Michael Hanselmann
    self.socket.listen(1024)
517 02cab3e7 Michael Hanselmann
518 02cab3e7 Michael Hanselmann
  def Stop(self):
519 02cab3e7 Michael Hanselmann
    self.socket.close()
520 02cab3e7 Michael Hanselmann
521 112d240d Guido Trotter
  def handle_accept(self):
522 112d240d Guido Trotter
    self._IncomingConnection()
523 02cab3e7 Michael Hanselmann
524 02cab3e7 Michael Hanselmann
  def OnSignal(self, signum):
525 02cab3e7 Michael Hanselmann
    if signum == signal.SIGCHLD:
526 02cab3e7 Michael Hanselmann
      self._CollectChildren(True)
527 02cab3e7 Michael Hanselmann
528 02cab3e7 Michael Hanselmann
  def _CollectChildren(self, quick):
529 02cab3e7 Michael Hanselmann
    """Checks whether any child processes are done
530 02cab3e7 Michael Hanselmann

531 02cab3e7 Michael Hanselmann
    @type quick: bool
532 02cab3e7 Michael Hanselmann
    @param quick: Whether to only use non-blocking functions
533 02cab3e7 Michael Hanselmann

534 02cab3e7 Michael Hanselmann
    """
535 02cab3e7 Michael Hanselmann
    if not quick:
536 02cab3e7 Michael Hanselmann
      # Don't wait for other processes if it should be a quick check
537 02cab3e7 Michael Hanselmann
      while len(self._children) > self.MAX_CHILDREN:
538 02cab3e7 Michael Hanselmann
        try:
539 02cab3e7 Michael Hanselmann
          # Waiting without a timeout brings us into a potential DoS situation.
540 02cab3e7 Michael Hanselmann
          # As soon as too many children run, we'll not respond to new
541 02cab3e7 Michael Hanselmann
          # requests. The real solution would be to add a timeout for children
542 02cab3e7 Michael Hanselmann
          # and killing them after some time.
543 7c4d6c7b Michael Hanselmann
          pid, _ = os.waitpid(0, 0)
544 02cab3e7 Michael Hanselmann
        except os.error:
545 02cab3e7 Michael Hanselmann
          pid = None
546 02cab3e7 Michael Hanselmann
        if pid and pid in self._children:
547 02cab3e7 Michael Hanselmann
          self._children.remove(pid)
548 02cab3e7 Michael Hanselmann
549 02cab3e7 Michael Hanselmann
    for child in self._children:
550 02cab3e7 Michael Hanselmann
      try:
551 1122eb25 Iustin Pop
        pid, _ = os.waitpid(child, os.WNOHANG)
552 02cab3e7 Michael Hanselmann
      except os.error:
553 02cab3e7 Michael Hanselmann
        pid = None
554 02cab3e7 Michael Hanselmann
      if pid and pid in self._children:
555 02cab3e7 Michael Hanselmann
        self._children.remove(pid)
556 02cab3e7 Michael Hanselmann
557 02cab3e7 Michael Hanselmann
  def _IncomingConnection(self):
558 02cab3e7 Michael Hanselmann
    """Called for each incoming connection
559 02cab3e7 Michael Hanselmann

560 02cab3e7 Michael Hanselmann
    """
561 b459a848 Andrea Spadaccini
    # pylint: disable=W0212
562 02cab3e7 Michael Hanselmann
    (connection, client_addr) = self.socket.accept()
563 02cab3e7 Michael Hanselmann
564 02cab3e7 Michael Hanselmann
    self._CollectChildren(False)
565 02cab3e7 Michael Hanselmann
566 02cab3e7 Michael Hanselmann
    pid = os.fork()
567 02cab3e7 Michael Hanselmann
    if pid == 0:
568 02cab3e7 Michael Hanselmann
      # Child process
569 02cab3e7 Michael Hanselmann
      try:
570 bcb1a39e Michael Hanselmann
        # The client shouldn't keep the listening socket open. If the parent
571 bcb1a39e Michael Hanselmann
        # process is restarted, it would fail when there's already something
572 bcb1a39e Michael Hanselmann
        # listening (in this case its own child from a previous run) on the
573 bcb1a39e Michael Hanselmann
        # same port.
574 bcb1a39e Michael Hanselmann
        try:
575 bcb1a39e Michael Hanselmann
          self.socket.close()
576 bcb1a39e Michael Hanselmann
        except socket.error:
577 bcb1a39e Michael Hanselmann
          pass
578 bcb1a39e Michael Hanselmann
        self.socket = None
579 bcb1a39e Michael Hanselmann
580 82869978 Michael Hanselmann
        # In case the handler code uses temporary files
581 82869978 Michael Hanselmann
        utils.ResetTempfileModule()
582 82869978 Michael Hanselmann
583 e0003509 Michael Hanselmann
        self.request_executor(self, self.handler, connection, client_addr)
584 b459a848 Andrea Spadaccini
      except Exception: # pylint: disable=W0703
585 02cab3e7 Michael Hanselmann
        logging.exception("Error while handling request from %s:%s",
586 02cab3e7 Michael Hanselmann
                          client_addr[0], client_addr[1])
587 02cab3e7 Michael Hanselmann
        os._exit(1)
588 02cab3e7 Michael Hanselmann
      os._exit(0)
589 02cab3e7 Michael Hanselmann
    else:
590 02cab3e7 Michael Hanselmann
      self._children.append(pid)
591 02cab3e7 Michael Hanselmann
592 e0003509 Michael Hanselmann
593 e0003509 Michael Hanselmann
class HttpServerHandler(object):
594 e0003509 Michael Hanselmann
  """Base class for handling HTTP server requests.
595 e0003509 Michael Hanselmann

596 e0003509 Michael Hanselmann
  Users of this class must subclass it and override the L{HandleRequest}
597 e0003509 Michael Hanselmann
  function.
598 e0003509 Michael Hanselmann

599 e0003509 Michael Hanselmann
  """
600 f8bd7df3 Michael Hanselmann
  def PreHandleRequest(self, req):
601 f8bd7df3 Michael Hanselmann
    """Called before handling a request.
602 f8bd7df3 Michael Hanselmann

603 5bbd3f7f Michael Hanselmann
    Can be overridden by a subclass.
604 f8bd7df3 Michael Hanselmann

605 f8bd7df3 Michael Hanselmann
    """
606 f8bd7df3 Michael Hanselmann
607 02cab3e7 Michael Hanselmann
  def HandleRequest(self, req):
608 02cab3e7 Michael Hanselmann
    """Handles a request.
609 02cab3e7 Michael Hanselmann

610 5bbd3f7f Michael Hanselmann
    Must be overridden by subclass.
611 02cab3e7 Michael Hanselmann

612 02cab3e7 Michael Hanselmann
    """
613 02cab3e7 Michael Hanselmann
    raise NotImplementedError()
614 377ae13e Michael Hanselmann
615 377ae13e Michael Hanselmann
  @staticmethod
616 377ae13e Michael Hanselmann
  def FormatErrorMessage(values):
617 377ae13e Michael Hanselmann
    """Formats the body of an error message.
618 377ae13e Michael Hanselmann

619 377ae13e Michael Hanselmann
    @type values: dict
620 377ae13e Michael Hanselmann
    @param values: dictionary with keys C{code}, C{message} and C{explain}.
621 377ae13e Michael Hanselmann
    @rtype: tuple; (string, string)
622 377ae13e Michael Hanselmann
    @return: Content-type and response body
623 377ae13e Michael Hanselmann

624 377ae13e Michael Hanselmann
    """
625 377ae13e Michael Hanselmann
    return (DEFAULT_ERROR_CONTENT_TYPE, DEFAULT_ERROR_MESSAGE % values)