tools/lldbmacros/core/cvalue.py

   1 """
   2 Defines a class value which encapsulates the basic lldb Scripting Bridge APIs. This provides an easy
   3 wrapper to extract information from C based constructs.
   4  |------- core.value------------|
   5  | |--lldb Scripting Bridge--|  |
   6  | |    |--lldb core--|      |  |
   7  | |-------------------------|  |
   8  |------------------------------|
   9 Use the member function GetSBValue() to access the base Scripting Bridge value.
  10 """
  11 import lldb
  12 import re
  13 from lazytarget import *
  14
  15 _cstring_rex = re.compile("((?:\s*|const\s+)\s*char(?:\s+\*|\s+[A-Za-z_0-9]*\s*\[|)\s*)",re.MULTILINE|re.DOTALL)
  16
  17 class value(object):
  18     '''A class designed to wrap lldb.SBValue() objects so the resulting object
  19     can be used as a variable would be in code. So if you have a Point structure
  20     variable in your code in the current frame named "pt", you can initialize an instance
  21     of this class with it:
  22
  23     pt = lldb.value(lldb.frame.FindVariable("pt"))
  24     print pt
  25     print pt.x
  26     print pt.y
  27
  28     pt = lldb.value(lldb.frame.FindVariable("rectangle_array"))
  29     print rectangle_array[12]
  30     print rectangle_array[5].origin.x'''
  31     def __init__(self, sbvalue):
  32         #_sbval19k84obscure747 is specifically chosen to be obscure.
  33         #This avoids conflicts when attributes could mean any field value in code
  34         self._sbval19k84obscure747 = sbvalue
  35         self._sbval19k84obscure747_type = sbvalue.GetType()
  36         self._sbval19k84obscure747_is_ptr = sbvalue.GetType().IsPointerType()
  37         self.sbvalue = sbvalue
  38
  39     def __nonzero__(self):
  40         return ( self._sbval19k84obscure747.__nonzero__() and self._GetValueAsUnsigned() != 0 )
  41
  42     def __repr__(self):
  43         return self._sbval19k84obscure747.__str__()
  44
  45     def __cmp__(self, other):
  46         if type(other) is int or type(other) is long:
  47             me = int(self)
  48             if type(me) is long:
  49                 other = long(other)
  50             return me.__cmp__(other)
  51         if type(other) is value:
  52             try:
  53                 return int(self).__cmp__(int(other))
  54             except TypeError: # Try promoting to long
  55                 return long(self).__cmp__(long(other))
  56         raise TypeError("Cannot compare value with type {}".format(type(other)))
  57
  58     def __str__(self):
  59         global _cstring_rex
  60         type_name = self._sbval19k84obscure747_type.GetName()
  61         if len(_cstring_rex.findall(type_name)) > 0 :
  62             return self._GetValueAsString()
  63         summary = self._sbval19k84obscure747.GetSummary()
  64         if summary:
  65             return summary.strip('"')
  66         return self._sbval19k84obscure747.__str__()
  67
  68     def __getitem__(self, key):
  69         # Allow array access if this value has children...
  70         if type(key) is slice:
  71             _start = int(key.start)
  72             _end = int(key.stop)
  73             _step = 1
  74             if key.step != None:
  75                 _step = int(key.step)
  76             retval = []
  77             while _start < _end:
  78                 retval.append(self[_start])
  79                 _start += _step
  80             return retval
  81         if type(key) in (int, long):
  82             return value(self._sbval19k84obscure747.GetValueForExpressionPath("[%i]" % key))
  83         if type(key) is value:
  84             return value(self._sbval19k84obscure747.GetValueForExpressionPath("[%i]" % int(key)))
  85         raise TypeError("Cannot fetch Array item for this type")
  86
  87     def __getattr__(self, name):
  88         child_sbvalue = self._sbval19k84obscure747.GetChildMemberWithName (name)
  89         if child_sbvalue:
  90             return value(child_sbvalue)
  91         raise AttributeError("No field by name: "+name )
  92
  93     def __add__(self, other):
  94         return int(self) + int(other)
  95
  96     def __radd__(self, other):
  97         return int(self) + int(other)
  98
  99     def __sub__(self, other):
 100         return int(self) - int(other)
 101
 102     def __rsub__(self, other):
 103         return int(other) - int(self)
 104
 105     def __mul__(self, other):
 106         return int(self) * int(other)
 107
 108     def __rmul__(self, other):
 109         return int(self) * int(other)
 110
 111     def __floordiv__(self, other):
 112         return int(self) // int(other)
 113
 114     def __mod__(self, other):
 115         return int(self) % int(other)
 116
 117     def __rmod__(self, other):
 118         return int(other) % int(self)
 119
 120     def __divmod__(self, other):
 121         return int(self) % int(other)
 122
 123     def __rdivmod__(self, other):
 124         return int(other) % int(self)
 125
 126     def __pow__(self, other):
 127         return int(self) ** int(other)
 128
 129     def __lshift__(self, other):
 130         return int(self) << int(other)
 131
 132     def __rshift__(self, other):
 133         return int(self) >> int(other)
 134
 135     def __and__(self, other):
 136         return int(self) & int(other)
 137
 138     def __rand(self, other):
 139         return int(self) & int(other)
 140
 141     def __xor__(self, other):
 142         return int(self) ^ int(other)
 143
 144     def __or__(self, other):
 145         return int(self) | int(other)
 146
 147     def __div__(self, other):
 148         return int(self) / int(other)
 149
 150     def __rdiv__(self, other):
 151         return int(other)/int(self)
 152
 153     def __truediv__(self, other):
 154         return int(self) / int(other)
 155
 156     def __iadd__(self, other):
 157         result = self.__add__(other)
 158         self._sbval19k84obscure747.SetValueFromCString (str(result))
 159         return result
 160
 161     def __isub__(self, other):
 162         result = self.__sub__(other)
 163         self._sbval19k84obscure747.SetValueFromCString (str(result))
 164         return result
 165
 166     def __imul__(self, other):
 167         result = self.__mul__(other)
 168         self._sbval19k84obscure747.SetValueFromCString (str(result))
 169         return result
 170
 171     def __idiv__(self, other):
 172         result = self.__div__(other)
 173         self._sbval19k84obscure747.SetValueFromCString (str(result))
 174         return result
 175
 176     def __itruediv__(self, other):
 177         result = self.__truediv__(other)
 178         self._sbval19k84obscure747.SetValueFromCString (str(result))
 179         return result
 180
 181     def __ifloordiv__(self, other):
 182         result =  self.__floordiv__(self, other)
 183         self._sbval19k84obscure747.SetValueFromCString (str(result))
 184         return result
 185
 186     def __imod__(self, other):
 187         result =  self.__and__(self, other)
 188         self._sbval19k84obscure747.SetValueFromCString (str(result))
 189         return result
 190
 191     def __ipow__(self, other):
 192         result = self.__pow__(self, other)
 193         self._sbval19k84obscure747.SetValueFromCString (str(result))
 194         return result
 195
 196     def __ipow__(self, other, modulo):
 197         result = self.__pow__(self, other, modulo)
 198         self._sbval19k84obscure747.SetValueFromCString (str(result))
 199         return result
 200
 201     def __ilshift__(self, other):
 202         result = self.__lshift__(other)
 203         self._sbval19k84obscure747.SetValueFromCString (str(result))
 204         return result
 205
 206     def __irshift__(self, other):
 207         result =  self.__rshift__(other)
 208         self._sbval19k84obscure747.SetValueFromCString (str(result))
 209         return result
 210
 211     def __iand__(self, other):
 212         result =  self.__and__(self, other)
 213         self._sbval19k84obscure747.SetValueFromCString (str(result))
 214         return result
 215
 216     def __ixor__(self, other):
 217         result =  self.__xor__(self, other)
 218         self._sbval19k84obscure747.SetValueFromCString (str(result))
 219         return result
 220
 221     def __ior__(self, other):
 222         result =  self.__ior__(self, other)
 223         self._sbval19k84obscure747.SetValueFromCString (str(result))
 224         return result
 225
 226     def __neg__(self):
 227         return -int(self)
 228
 229     def __pos__(self):
 230         return +int(self)
 231
 232     def __abs__(self):
 233         return abs(int(self))
 234
 235     def __invert__(self):
 236         return ~int(self)
 237
 238     def __complex__(self):
 239         return complex (int(self))
 240
 241     def __int__(self):
 242         if self._sbval19k84obscure747_is_ptr:
 243             return self._GetValueAsUnsigned()
 244         tname= self._sbval19k84obscure747_type.GetName()
 245         if tname.find('uint') >= 0 or tname.find('unsigned') >= 0:
 246             return self._GetValueAsUnsigned()
 247         retval = self._sbval19k84obscure747.GetValueAsSigned()
 248         # <rdar://problem/12481949> lldb python: GetValueAsSigned does not return the correct value
 249         if (retval & 0x80000000):
 250             retval = retval - 0x100000000
 251         return retval
 252
 253     def __long__(self):
 254         return self._sbval19k84obscure747.GetValueAsSigned()
 255
 256     def __float__(self):
 257         return float (self._sbval19k84obscure747.GetValueAsSigned())
 258
 259     def __oct__(self):
 260         return '0%o' % self._GetValueAsUnsigned()
 261
 262     def __hex__(self):
 263         return '0x%x' % self._GetValueAsUnsigned()
 264
 265     def __eq__(self, other):
 266         self_err = lldb.SBError()
 267         other_err = lldb.SBError()
 268         self_val = self._sbval19k84obscure747.GetValueAsUnsigned(self_err)
 269         if self_err.fail:
 270                 raise ValueError("unable to extract value of self")
 271         if type(other) is value:
 272             other_val = other._sbval19k84obscure747.GetValueAsUnsigned(other_err)
 273             if other_err.fail:
 274                 raise ValueError("unable to extract value of other")
 275             return self_val == other_val
 276         if type(other) is int:
 277             return int(self) == other
 278         raise TypeError("Equality operation is not defined for this type.")
 279
 280     def __neq__(self, other):
 281         return not self.__eq__(other)
 282
 283     def GetSBValue(self):
 284         return self._sbval19k84obscure747
 285
 286     def __getstate__(self):
 287         err = lldb.SBError()
 288         if self._sbval19k84obscure747_is_ptr:
 289             addr = self._sbval19k84obscure747.GetValueAsUnsigned()
 290             size = self._sbval19k84obscure747_type.GetPointeeType().GetByteSize()
 291         else:
 292             addr = self._sbval19k84obscure747.AddressOf().GetValueAsUnsigned()
 293             size = self._sbval19k84obscure747_type.GetByteSize()
 294
 295         content = LazyTarget.GetProcess().ReadMemory(addr, size, err)
 296         if err.fail:
 297             content = ''
 298         return content
 299
 300     def _GetValueAsSigned(self):
 301         if self._sbval19k84obscure747_is_ptr:
 302             print "ERROR: You cannot get 'int' from pointer type %s, please use unsigned(obj) for such purposes." % str(self._sbval19k84obscure747_type)
 303             raise ValueError("Cannot get signed int for pointer data.")
 304         serr = lldb.SBError()
 305         retval = self._sbval19k84obscure747.GetValueAsSigned(serr)
 306         if serr.success:
 307             return retval
 308         raise ValueError("Failed to read signed data. "+ str(self._sbval19k84obscure747) +"(type =" + str(self._sbval19k84obscure747_type) + ") Error description: " + serr.GetCString())
 309
 310     def _GetValueAsCast(self, dest_type):
 311         if type(dest_type) is not lldb.SBType:
 312             raise ValueError("Invalid type for dest_type: {}".format(type(dest_type)))
 313         addr = self._GetValueAsUnsigned()
 314         sbval = self._sbval19k84obscure747.target.CreateValueFromExpression("newname", "(void *)"+str(addr))
 315         val = value(sbval.Cast(dest_type))
 316         return val
 317
 318     def _GetValueAsUnsigned(self):
 319         serr = lldb.SBError()
 320         if self._sbval19k84obscure747_is_ptr:
 321             retval = self._sbval19k84obscure747.GetValueAsAddress()
 322         else:
 323             retval = self._sbval19k84obscure747.GetValueAsUnsigned(serr)
 324         if serr.success:
 325             return retval
 326         raise ValueError("Failed to read unsigned data. "+ str(self._sbval19k84obscure747) +"(type =" + str(self._sbval19k84obscure747_type) + ") Error description: " + serr.GetCString())
 327
 328     def _GetValueAsString(self, offset = 0, maxlen = 1024):
 329         serr = lldb.SBError()
 330         sbdata = None
 331         if self._sbval19k84obscure747_is_ptr:
 332             sbdata = self._sbval19k84obscure747.GetPointeeData(offset, maxlen)
 333         else:
 334             sbdata = self._sbval19k84obscure747.GetData()
 335
 336         retval = ''
 337         bytesize = sbdata.GetByteSize()
 338         if bytesize == 0 :
 339             #raise ValueError('Unable to read value as string')
 340             return ''
 341         for i in range(0, bytesize) :
 342             serr.Clear()
 343             ch = chr(sbdata.GetUnsignedInt8(serr, i))
 344             if serr.fail :
 345                 raise ValueError("Unable to read string data: " + serr.GetCString())
 346             if ch == '\0':
 347                 break
 348             retval += ch
 349         return retval
 350
 351     def __format__(self, format_spec):
 352         ret_format = "{0:"+format_spec+"}"
 353         # typechar is last char. see http://www.python.org/dev/peps/pep-3101/
 354         type_spec=format_spec.strip().lower()[-1]
 355         if type_spec == 'x':
 356             return ret_format.format(self._GetValueAsUnsigned())
 357         if type_spec == 'd':
 358             return ret_format.format(int(self))
 359         if type_spec == 's':
 360             return ret_format.format(str(self))
 361         if type_spec == 'o':
 362             return ret_format.format(int(oct(self)))
 363         if type_spec == 'c':
 364             return ret_format.format(int(self))
 365
 366         return "unknown format " + format_spec + str(self)
 367
 368
 369 def unsigned(val):
 370     """ Helper function to get unsigned value from core.value
 371         params: val - value (see value class above) representation of an integer type
 372         returns: int which is unsigned.
 373         raises : ValueError if the type cannot be represented as unsigned int.
 374     """
 375     if type(val) is value:
 376         return val._GetValueAsUnsigned()
 377     return int(val)
 378
 379 def sizeof(t):
 380     """ Find the byte size of a type.
 381         params: t - str : ex 'time_spec' returns equivalent of sizeof(time_spec) in C
 382                 t - value: ex a value object. returns size of the object
 383         returns: int - byte size length
 384     """
 385     if type(t) is value :
 386         return t.GetSBValue().GetByteSize()
 387     if type(t) is str:
 388         return gettype(t).GetByteSize()
 389     raise ValueError("Cannot get sizeof. Invalid argument")
 390
 391
 392 def dereference(val):
 393     """ Get a dereferenced obj for a pointer type obj
 394         params: val - value object representing a pointer type C construct in lldb
 395         returns: value - value
 396         ex. val = dereference(ptr_obj) #python
 397         is same as
 398             obj_ptr = (int *)0x1234  #C
 399             val = *obj_ptr           #C
 400     """
 401     if type(val) is value and val._sbval19k84obscure747_is_ptr:
 402         return value(val.GetSBValue().Dereference())
 403     raise TypeError('Cannot dereference this type.')
 404
 405 def addressof(val):
 406     """ Get address of a core.value object.
 407         params: val - value object representing a C construct in lldb
 408         returns: value - value object referring to 'type(val) *' type
 409         ex. addr = addressof(hello_obj)  #python
 410         is same as
 411            uintptr_t addr = (uintptr_t)&hello_obj  #C
 412     """
 413     if type(val) is value:
 414         return value(val.GetSBValue().AddressOf())
 415     raise TypeError("Cannot do addressof for non-value type objects")
 416
 417 def cast(obj, target_type):
 418     """ Type cast an object to another C type.
 419         params:
 420             obj - core.value  object representing some C construct in lldb
 421             target_type - str : ex 'char *'
 422                         - lldb.SBType :
 423     """
 424     dest_type = target_type
 425     if type(target_type) is str:
 426         dest_type = gettype(target_type)
 427     elif type(target_type) is value:
 428         dest_type = target_type.GetSBValue().GetType()
 429
 430     if type(obj) is value:
 431         return obj._GetValueAsCast(dest_type)
 432     elif type(obj) is int:
 433         print "ERROR: You cannot cast an 'int' to %s, please use kern.GetValueFromAddress() for such purposes." % str(target_type)
 434     raise TypeError("object of type %s cannot be casted to %s" % (str(type(obj)), str(target_type)))
 435
 436 def containerof(obj, target_type, field_name):
 437     """ Type cast an object to another C type from a pointer to a field.
 438         params:
 439             obj - core.value  object representing some C construct in lldb
 440             target_type - str : ex 'struct thread'
 441                         - lldb.SBType :
 442             field_name - the field name within the target_type obj is a pointer to
 443     """
 444     addr = int(obj) - getfieldoffset(target_type, field_name)
 445     obj = value(obj.GetSBValue().CreateValueFromExpression(None,'(void *)'+str(addr)))
 446     return cast(obj, target_type + " *")
 447
 448
 449 _value_types_cache={}
 450
 451 def gettype(target_type):
 452     """ Returns lldb.SBType of the given target_type
 453         params:
 454             target_type - str, ex. 'char', 'uint32_t' etc
 455         returns:
 456             lldb.SBType - SBType corresponding to the given target_type
 457         raises:
 458             NameError  - Incase the type is not identified
 459     """
 460     global _value_types_cache
 461     target_type = str(target_type).strip()
 462     if target_type in _value_types_cache:
 463         return _value_types_cache[target_type]
 464
 465     target_type = target_type.strip()
 466
 467     requested_type_is_struct = False
 468     m = re.match(r'\s*struct\s*(.*)$', target_type)
 469     if m:
 470         requested_type_is_struct = True
 471         target_type = m.group(1)
 472
 473     tmp_type = None
 474     requested_type_is_pointer = False
 475     if target_type.endswith('*') :
 476         requested_type_is_pointer = True
 477
 478     # tmp_type = LazyTarget.GetTarget().FindFirstType(target_type.rstrip('*').strip())
 479     search_type = target_type.rstrip('*').strip()
 480     type_arr = [t for t in LazyTarget.GetTarget().FindTypes(search_type)]
 481
 482     if requested_type_is_struct:
 483         type_arr = [t for t in type_arr if t.type == lldb.eTypeClassStruct]
 484
 485     # After the sort, the struct type with more fields will be at index [0].
 486     # This hueristic helps selecting struct type with more fields compared to ones with "opaque" members
 487     type_arr.sort(reverse=True, key=lambda x: x.GetNumberOfFields())
 488     if len(type_arr) > 0:
 489         tmp_type = type_arr[0]
 490     else:
 491         raise NameError('Unable to find type '+target_type)
 492
 493     if not tmp_type.IsValid():
 494         raise NameError('Unable to Cast to type '+target_type)
 495
 496     if requested_type_is_pointer:
 497         tmp_type = tmp_type.GetPointerType()
 498     _value_types_cache[target_type] = tmp_type
 499
 500     return _value_types_cache[target_type]
 501
 502
 503 def getfieldoffset(struct_type, field_name):
 504     """ Returns the byte offset of a field inside a given struct
 505         Understands anonymous unions and field names in sub-structs
 506         params:
 507             struct_type - str or lldb.SBType, ex. 'struct ipc_port *' or port.gettype()
 508             field_name  - str, name of the field inside the struct ex. 'ip_messages'
 509         returns:
 510             int - byte offset of the field_name inside the struct_type
 511         raises:
 512             TypeError  - - In case the struct_type has no field with the name field_name
 513     """
 514
 515     if type(struct_type) == str:
 516         struct_type = gettype(struct_type)
 517
 518     if '.' in field_name :
 519         # Handle recursive fields in sub-structs
 520         components = field_name.split('.', 1)
 521         for field in struct_type.get_fields_array():
 522             if str(field.GetName()) == components[0]:
 523                 return getfieldoffset(struct_type, components[0]) + getfieldoffset(field.GetType(), components[1])
 524         raise TypeError('Field name "%s" not found in type "%s"' % (components[0], str(struct_type)))
 525
 526     offset = 0
 527     for field in struct_type.get_fields_array():
 528         if str(field.GetName()) == field_name:
 529             return field.GetOffsetInBytes()
 530
 531         # Hack for anonymous unions - the compiler does this, so cvalue should too
 532         if field.GetName() is None and field.GetType().GetTypeClass() == lldb.eTypeClassUnion :
 533             for union_field in field.GetType().get_fields_array():
 534                 if str(union_field.GetName()) == field_name:
 535                     return union_field.GetOffsetInBytes() + field.GetOffsetInBytes()
 536     raise TypeError('Field name "%s" not found in type "%s"' % (field_name, str(struct_type)))
 537
 538 def islong(x):
 539     """ Returns True if a string represents a long integer, False otherwise
 540     """
 541     try:
 542         long(x,16)
 543     except ValueError:
 544         try:
 545             long(x)
 546         except ValueError:
 547             return False
 548     return True
 549
 550 def readmemory(val):
 551     """ Returns a string of hex data that is referenced by the value.
 552         params: val - a value object.
 553         return: str - string of hex bytes.
 554         raises: TypeError if val is not a valid type
 555     """
 556     if not type(val) is value:
 557         raise TypeError('%s is not of type value' % str(type(val)))
 558     return val.__getstate__()