gdb/python/lib/gdb/function/strfns.py

   1 # Useful gdb string convenience functions.
   2 # Copyright (C) 2012-2021 Free Software Foundation, Inc.
   3
   4 # This program is free software; you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation; either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 """$_memeq, $_strlen, $_streq, $_regex"""
  18
  19 import gdb
  20 import re
  21
  22
  23 class _MemEq(gdb.Function):
  24   """$_memeq - compare bytes of memory.
  25
  26 Usage: $_memeq (A, B, LEN)
  27
  28 Returns:
  29   True if LEN bytes at A and B compare equally."""
  30   def __init__(self):
  31     super(_MemEq, self).__init__("_memeq")
  32
  33   def invoke(self, a, b, length):
  34     if length < 0:
  35       raise ValueError("length must be non-negative")
  36     if length == 0:
  37       return True
  38     # The argument(s) to vector are [low_bound,]high_bound.
  39     byte_vector = gdb.lookup_type("char").vector(length - 1)
  40     ptr_byte_vector = byte_vector.pointer()
  41     a_ptr = a.reinterpret_cast(ptr_byte_vector)
  42     b_ptr = b.reinterpret_cast(ptr_byte_vector)
  43     return a_ptr.dereference() == b_ptr.dereference()
  44
  45
  46 class _StrLen(gdb.Function):
  47   """$_strlen - compute string length.
  48
  49 Usage: $_strlen (A)
  50
  51 Returns:
  52   Length of string A, assumed to be a string in the current language."""
  53   def __init__(self):
  54     super(_StrLen, self).__init__("_strlen")
  55
  56   def invoke(self, a):
  57     s = a.string()
  58     return len(s)
  59
  60
  61 class _StrEq(gdb.Function):
  62   """$_streq - check string equality.
  63
  64 Usage: $_streq (A, B)
  65
  66 Returns:
  67   True if A and B are identical strings in the current language.
  68
  69 Example (amd64-linux):
  70   catch syscall open
  71   cond $bpnum $_streq((char*) $rdi, "foo")"""
  72   def __init__(self):
  73     super(_StrEq, self).__init__("_streq")
  74
  75   def invoke(self, a, b):
  76     return a.string() == b.string()
  77
  78
  79 class _RegEx(gdb.Function):
  80   """$_regex - check if a string matches a regular expression.
  81
  82 Usage: $_regex (STRING, REGEX)
  83
  84 Returns:
  85   True if string STRING (in the current language) matches the
  86   regular expression REGEX."""
  87   def __init__(self):
  88     super(_RegEx, self).__init__("_regex")
  89
  90   def invoke(self, string, regex):
  91     s = string.string()
  92     r = re.compile(regex.string())
  93     return bool(r.match(s))
  94
  95
  96 # GDB will import us automagically via gdb/__init__.py.
  97 _MemEq()
  98 _StrLen()
  99 _StrEq()
 100 _RegEx()