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