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 69 70ContainerOf() 71 72 73BIG_ENDIAN = 0 74LITTLE_ENDIAN = 1 75target_endianness = None 76 77 78def get_target_endianness(): 79 global target_endianness 80 if target_endianness is None: 81 endian = gdb.execute("show endian", to_string=True) 82 if "little endian" in endian: 83 target_endianness = LITTLE_ENDIAN 84 elif "big endian" in endian: 85 target_endianness = BIG_ENDIAN 86 else: 87 raise gdb.GdbError("unknown endianness '{0}'".format(str(endian))) 88 return target_endianness 89 90 91def read_memoryview(inf, start, length): 92 return memoryview(inf.read_memory(start, length)) 93 94 95def read_u16(buffer): 96 value = [0, 0] 97 98 if type(buffer[0]) is str: 99 value[0] = ord(buffer[0]) 100 value[1] = ord(buffer[1]) 101 else: 102 value[0] = buffer[0] 103 value[1] = buffer[1] 104 105 if get_target_endianness() == LITTLE_ENDIAN: 106 return value[0] + (value[1] << 8) 107 else: 108 return value[1] + (value[0] << 8) 109 110 111def read_u32(buffer): 112 if get_target_endianness() == LITTLE_ENDIAN: 113 return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16) 114 else: 115 return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16) 116 117 118def read_u64(buffer): 119 if get_target_endianness() == LITTLE_ENDIAN: 120 return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32) 121 else: 122 return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32) 123 124 125target_arch = None 126 127 128def is_target_arch(arch): 129 if hasattr(gdb.Frame, 'architecture'): 130 return arch in gdb.newest_frame().architecture().name() 131 else: 132 global target_arch 133 if target_arch is None: 134 target_arch = gdb.execute("show architecture", to_string=True) 135 return arch in target_arch 136 137 138GDBSERVER_QEMU = 0 139GDBSERVER_KGDB = 1 140gdbserver_type = None 141 142 143def get_gdbserver_type(): 144 def exit_handler(event): 145 global gdbserver_type 146 gdbserver_type = None 147 gdb.events.exited.disconnect(exit_handler) 148 149 def probe_qemu(): 150 try: 151 return gdb.execute("monitor info version", to_string=True) != "" 152 except gdb.error: 153 return False 154 155 def probe_kgdb(): 156 try: 157 thread_info = gdb.execute("info thread 2", to_string=True) 158 return "shadowCPU0" in thread_info 159 except gdb.error: 160 return False 161 162 global gdbserver_type 163 if gdbserver_type is None: 164 if probe_qemu(): 165 gdbserver_type = GDBSERVER_QEMU 166 elif probe_kgdb(): 167 gdbserver_type = GDBSERVER_KGDB 168 if gdbserver_type is not None and hasattr(gdb, 'events'): 169 gdb.events.exited.connect(exit_handler) 170 return gdbserver_type 171 172 173def gdb_eval_or_none(expresssion): 174 try: 175 return gdb.parse_and_eval(expresssion) 176 except gdb.error: 177 return None 178 179 180def dentry_name(d): 181 parent = d['d_parent'] 182 if parent == d or parent == 0: 183 return "" 184 p = dentry_name(d['d_parent']) + "/" 185 return p + d['d_iname'].string() 186