Source Code for Module envi.expression

 1  """
 
 2  Unified expression helpers.
 
 3  """ 
 4  
 
 5 -def evaluate(pycode, locals): 
 6      return eval(pycode, {}, locals) 
 7  
 
 8 -class ExpressionLocals(dict): 
 9      """
 
10      An object to act as the locals dictionary for the evaluation
 
11      of envi expressions.  You may pass in an envi.resolver.SymbolResolver
 
12      object to automagically use symbols in your expressions.
 
13      """ 
14 -    def __init__(self, symobj=None): 
15          dict.__init__(self) 
16          self.symobj = symobj 
17  
 
18 -    def __getitem__(self, name): 
19          if self.symobj != None: 
20              ret = self.symobj.getSymByName(name) 
21              if ret != None: return ret 
22          return dict.__getitem__(self, name) 
23  
 
24 -class MemoryExpressionLocals(ExpressionLocals): 
25  
 
26 -    def __init__(self, memobj, symobj=None): 
27          ExpressionLocals.__init__(self, symobj=symobj) 
28          self.memobj = memobj 
29          self.update({
 
30              'mapbase':self.mapbase,
 
31              'maplen':self.maplen,
 
32              'ispoi':self.ispoi,
 
33              'mem':self.mem,
 
34              'poi':self.poi,
 
35              'sym':self.sym,
 
36          }) 
37  
 
38 -    def sym(self, symstr): 
39          '''
 
40          An easy to use utility for symbols which have un-pythonic names.
 
41  
 
42          Example x = sym('kernel32.??2@$$FYAPAXI@Z')
 
43          ''' 
44          return long(evaluate(symstr, self)) 
45  
 
46 -    def mapbase(self, address): 
47          """
 
48          The expression mapbase(address) returns the base address of the
 
49          memory mapped area containing "address"
 
50          """ 
51          map = self.memobj.getMemoryMap(address) 
52          if not map: 
53              raise Exception("ERROR - un-mapped address in mapbase()") 
54          return map[0] 
55  
 
56 -    def maplen(self, address): 
57          """
 
58          The expression maplen(address) returns the length of the
 
59          memory mapped area containing "address".
 
60          """ 
61          map = self.memobj.getMemoryMap(address) 
62          if not map: 
63              raise Exception("ERROR - un-mapped address in maplen()") 
64          return map[1] 
65  
 
66 -    def ispoi(self, addr): 
67          """
 
68          The expression ispoi(value) returns True if the specified value
 
69          is a valid pointer.  Otherwise, False.
 
70          """ 
71          return self.memobj.isValidPointer(addr) 
72  
 
73 -    def mem(self, addr, size): 
74          """
 
75          Read and return memory.
 
76  
 
77          Example: mem(ecx, 20)
 
78          """ 
79          return self.memobj.readMemory(addr, size) 
80  
 
81 -    def poi(self, address): 
82          """
 
83          When expression contains "poi(addr)" this will return
 
84          the address pointed to by addr.
 
85          """ 
86          return self.memobj.readMemoryFormat(address, "P")[0] 
87