1# 2# gdb helper commands and functions for Linux kernel debugging 3# 4# common utilities 5# 6# Copyright (c) Siemens AG, 2011-2013 7# 8# Authors: 9# Jan Kiszka <jan.kiszka@siemens.com> 10# 11# This work is licensed under the terms of the GNU GPL version 2. 12# 13 14import gdb 15 16 17class CachedType: 18 def __init__(self, name): 19 self._type = None 20 self._name = name 21 22 def _new_objfile_handler(self, event): 23 self._type = None 24 gdb.events.new_objfile.disconnect(self._new_objfile_handler) 25 26 def get_type(self): 27 if self._type is None: 28 self._type = gdb.lookup_type(self._name) 29 if self._type is None: 30 raise gdb.GdbError( 31 "cannot resolve type '{0}'".format(self._name)) 32 if hasattr(gdb, 'events') and hasattr(gdb.events, 'new_objfile'): 33 gdb.events.new_objfile.connect(self._new_objfile_handler) 34 return self._type 35 36 37long_type = CachedType("long") 38 39 40def get_long_type(): 41 global long_type 42 return long_type.get_type() 43 44 45def offset_of(typeobj, field): 46 element = gdb.Value(0).cast(typeobj) 47 return int(str(element[field].address).split()[0], 16) 48 49 50def container_of(ptr, typeobj, member): 51 return (ptr.cast(get_long_type()) - 52 offset_of(typeobj, member)).cast(typeobj) 53 54 55class ContainerOf(gdb.Function): 56 """Return pointer to containing data structure. 57 58$container_of(PTR, "TYPE", "ELEMENT"): Given PTR, return a pointer to the 59data structure of the type TYPE in which PTR is the address of ELEMENT. 60Note that TYPE and ELEMENT have to be quoted as strings.""" 61 62 def __init__(self): 63 super(ContainerOf, self).__init__("container_of") 64 65 def invoke(self, ptr, typename, elementname): 66 return container_of(ptr, gdb.lookup_type(typename.string()).pointer(), 67 elementname.string()) 68 69ContainerOf() 70 71 72BIG_ENDIAN = 0 73LITTLE_ENDIAN = 1 74target_endianness = None 75 76 77def get_target_endianness(): 78 global target_endianness 79 if target_endianness is None: 80 endian = gdb.execute("show endian", to_string=True) 81 if "little endian" in endian: 82 target_endianness = LITTLE_ENDIAN 83 elif "big endian" in endian: 84 target_endianness = BIG_ENDIAN 85 else: 86 raise gdb.GdgError("unknown endianness '{0}'".format(str(endian))) 87 return target_endianness 88 89 90def read_u16(buffer): 91 if get_target_endianness() == LITTLE_ENDIAN: 92 return ord(buffer[0]) + (ord(buffer[1]) << 8) 93 else: 94 return ord(buffer[1]) + (ord(buffer[0]) << 8) 95 96 97def read_u32(buffer): 98 if get_target_endianness() == LITTLE_ENDIAN: 99 return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16) 100 else: 101 return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16) 102 103 104def read_u64(buffer): 105 if get_target_endianness() == LITTLE_ENDIAN: 106 return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32) 107 else: 108 return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32) 109 110 111target_arch = None 112 113 114def is_target_arch(arch): 115 if hasattr(gdb.Frame, 'architecture'): 116 return arch in gdb.newest_frame().architecture().name() 117 else: 118 global target_arch 119 if target_arch is None: 120 target_arch = gdb.execute("show architecture", to_string=True) 121 return arch in target_arch 122 123 124GDBSERVER_QEMU = 0 125GDBSERVER_KGDB = 1 126gdbserver_type = None 127 128 129def get_gdbserver_type(): 130 def exit_handler(event): 131 global gdbserver_type 132 gdbserver_type = None 133 gdb.events.exited.disconnect(exit_handler) 134 135 def probe_qemu(): 136 try: 137 return gdb.execute("monitor info version", to_string=True) != "" 138 except: 139 return False 140 141 def probe_kgdb(): 142 try: 143 thread_info = gdb.execute("info thread 2", to_string=True) 144 return "shadowCPU0" in thread_info 145 except: 146 return False 147 148 global gdbserver_type 149 if gdbserver_type is None: 150 if probe_qemu(): 151 gdbserver_type = GDBSERVER_QEMU 152 elif probe_kgdb(): 153 gdbserver_type = GDBSERVER_KGDB 154 if not gdbserver_type is None and hasattr(gdb, 'events'): 155 gdb.events.exited.connect(exit_handler) 156 return gdbserver_type 157