sfatables/xmlrule.py

   1 import libxml2
   2 import libxslt
   3 from sfatables.globals import *
   4
   5 class XMLRule:
   6
   7     def apply_processor(self, type, doc, output_xpath_filter=None):
   8         processor = self.processors[type]
   9
  10         # XXX TO CLEAN UP
  11         filepath = os.path.join(sfatables_config, 'processors', processor)
  12         # XXX
  13
  14         styledoc = libxml2.parseFile(filepath)
  15         style = libxslt.parseStylesheetDoc(styledoc)
  16         result = style.applyStylesheet(doc, None)
  17         if (output_xpath_filter):
  18             p = result.xpathNewContext()
  19             xpath_result = p.xpathEval(output_xpath_filter)
  20             if (xpath_result == []):
  21                 raise Exception("Could not apply processor %s."%processor)
  22
  23             stylesheet_result = xpath_result
  24             p.xpathFreeContext()
  25         else:
  26             stylesheet_result = result #style.saveResultToString(result)
  27
  28         style.freeStylesheet()
  29         #doc.freeDoc()
  30         #result.freeDoc()
  31
  32         return stylesheet_result
  33
  34     def wrap_up(self, doc):
  35         filepath = os.path.join(sfatables_config, 'processors', self.final_processor)
  36
  37         if not os.path.exists(filepath):
  38             # TODO: final_processor is not there yet
  39             return doc#rspec
  40
  41         styledoc = libxml2.parseFile(filepath)
  42         style = libxslt.parseStylesheetDoc(styledoc)
  43         #doc = libxml2.parseDoc(rspec)
  44         result = style.applyStylesheet(doc, None)
  45         stylesheet_result = style.saveResultToString(result)
  46         style.freeStylesheet()
  47         doc.freeDoc()
  48         result.freeDoc()
  49
  50         import pdb
  51         pdb.set_trace()
  52         return stylesheet_result
  53
  54     def match(self, rspec):
  55         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  56         return (match_result[0].content=='True')
  57
  58     def target(self, rspec):
  59         target_result = self.apply_processor('target',rspec,None)
  60         return target_result
  61
  62     def apply_interpreted(self, rspec):
  63         # Interpreted
  64         #
  65         # output =
  66         #    if (match(match_args, rspec)
  67         #       then target(target_args, rspec)
  68         #       else rspec
  69
  70         if (self.match(rspec)):
  71             return self.target(rspec)
  72         else:
  73             return rspec
  74
  75
  76     def apply_compiled(rspec):
  77         # Not supported yet
  78         return None
  79
  80     def load_xml_extension (self, type, chain, rule_number):
  81         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
  82
  83         self.xmldoc = libxml2.parseFile(filename)
  84         p = self.xmldoc.xpathNewContext()
  85
  86         context = p.xpathEval('//context/@select')
  87         self.context[type] = context[0].content
  88
  89         processor = p.xpathEval('//processor/@filename')
  90
  91         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
  92         if (context != []):
  93             self.terminal = 1
  94
  95         self.processors[type] = processor[0].content
  96         self.arguments[type] = p.xpathEval('//rule')
  97
  98         p.xpathFreeContext()
  99
 100
 101     def wrap_rspec (self, type, rspec):
 102         argument = self.arguments[type]
 103         p = rspec.xmldoc.xpathNewContext()
 104         root_node = p.xpathEval('/RSpec')
 105         if (not root_node or not root_node):
 106             raise Exception('An evil aggregate manager sent me a malformed RSpec. Please see the stack trace to identify it.')
 107
 108         root_node.addChild(arguments[type])
 109         return rspec
 110
 111     def __init__(self, chain=None, rule_number=None):
 112         self.rule_number = None
 113         self.chain = None
 114         self.xmldoc = None
 115         self.terminal = 0
 116         self.final_processor = '__sfatables_wrap_up__.xsl'
 117
 118         self.arguments = {'match':None,'target':None}
 119         self.processors = {'match':None,'target':None}
 120         self.context = {'match':None,'target':None}
 121
 122         if (chain and rule_number):
 123             self.load_xml_extension('match', chain, rule_number)
 124             self.load_xml_extension('target',chain, rule_number)
 125             self.rule_number = rule_number
 126             self.chain = chain
 127         return
 128
 129     def free(self):
 130         self.xmldoc.freeDoc()