| # |
| # gdb helper commands and functions for Linux kernel debugging |
| # |
| # common utilities |
| # |
| # Copyright (c) Siemens AG, 2011-2013 |
| # |
| # Authors: |
| # Jan Kiszka <jan.kiszka@siemens.com> |
| # |
| # This work is licensed under the terms of the GNU GPL version 2. |
| # |
| |
| import gdb |
| |
| |
| class CachedType: |
| def __init__(self, name): |
| self._type = None |
| self._name = name |
| |
| def _new_objfile_handler(self, event): |
| self._type = None |
| gdb.events.new_objfile.disconnect(self._new_objfile_handler) |
| |
| def get_type(self): |
| if self._type is None: |
| self._type = gdb.lookup_type(self._name) |
| if self._type is None: |
| raise gdb.GdbError( |
| "cannot resolve type '{0}'".format(self._name)) |
| if hasattr(gdb, 'events') and hasattr(gdb.events, 'new_objfile'): |
| gdb.events.new_objfile.connect(self._new_objfile_handler) |
| return self._type |
| |
| |
| long_type = CachedType("long") |
| |
| |
| def get_long_type(): |
| global long_type |
| return long_type.get_type() |
| |
| |
| def offset_of(typeobj, field): |
| element = gdb.Value(0).cast(typeobj) |
| return int(str(element[field].address).split()[0], 16) |
| |
| |
| def container_of(ptr, typeobj, member): |
| return (ptr.cast(get_long_type()) - |
| offset_of(typeobj, member)).cast(typeobj) |
| |
| |
| class ContainerOf(gdb.Function): |
| """Return pointer to containing data structure. |
| |
| $container_of(PTR, "TYPE", "ELEMENT"): Given PTR, return a pointer to the |
| data structure of the type TYPE in which PTR is the address of ELEMENT. |
| Note that TYPE and ELEMENT have to be quoted as strings.""" |
| |
| def __init__(self): |
| super(ContainerOf, self).__init__("container_of") |
| |
| def invoke(self, ptr, typename, elementname): |
| return container_of(ptr, gdb.lookup_type(typename.string()).pointer(), |
| elementname.string()) |
| |
| ContainerOf() |