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pwndbg/pwndbg/dt.py

151 lines
4.0 KiB
Python

"""
Prints structures in a manner similar to Windbg's "dt" command.
"""
import re
import gdb
import pwndbg.memory
import pwndbg.typeinfo
def get_type(v):
t = v.type
while not t.name:
if t.code == gdb.TYPE_CODE_PTR:
t = t.target()
return t.name
def get_typename(t):
return str(t)
def get_arrsize(f):
t = f.type
if t.code != gdb.TYPE_CODE_ARRAY:
return 0
t2 = t.target()
s = t2.sizeof
return int(t.sizeof / t2.sizeof)
def get_field_by_name(obj, field):
# Dereference once
if obj.type.code == gdb.TYPE_CODE_PTR:
obj = obj.dereference()
for f in re.split(r"(->|\.|\[\d+\])", field):
if not f:
continue
if f == "->":
obj = obj.dereference()
elif f == ".":
pass
elif f.startswith("["):
n = int(f.strip("[]"))
obj = obj.cast(obj.dereference().type.pointer())
obj += n
obj = obj.dereference()
else:
obj = obj[f]
return obj
def happy(typename):
prefix = ""
if "unsigned" in typename:
prefix = "u"
typename = typename.replace("unsigned ", "")
return (
prefix
+ {
"char": "char",
"short int": "short",
"long int": "long",
"int": "int",
"long long": "longlong",
"float": "float",
"double": "double",
}[typename]
)
def dt(name="", addr=None, obj=None):
"""
Dump out a structure type Windbg style.
"""
# Return value is a list of strings.of
# We concatenate at the end.
rv = []
if obj and not name:
t = obj.type
while t.code == (gdb.TYPE_CODE_PTR):
t = t.target()
obj = obj.dereference()
name = str(t)
# Lookup the type name specified by the user
else:
t = pwndbg.typeinfo.load(name)
# If it's not a struct (e.g. int or char*), bail
if t.code not in (gdb.TYPE_CODE_STRUCT, gdb.TYPE_CODE_TYPEDEF, gdb.TYPE_CODE_UNION):
raise Exception("Not a structure: %s" % t)
# If an address was specified, create a Value of the
# specified type at that address.
if addr is not None:
obj = pwndbg.memory.poi(t, addr)
# Header, optionally include the name
header = name
if obj:
header = "%s @ %s" % (header, hex(int(obj.address)))
rv.append(header)
if t.strip_typedefs().code == gdb.TYPE_CODE_ARRAY:
return "Arrays not supported yet"
if t.strip_typedefs().code not in (gdb.TYPE_CODE_STRUCT, gdb.TYPE_CODE_UNION):
t = {name: obj or gdb.Value(0).cast(t)}
for name, field in t.items():
# Offset into the parent structure
o = getattr(field, "bitpos", 0) // 8
b = getattr(field, "bitpos", 0) % 8
extra = str(field.type)
ftype = field.type.strip_typedefs()
if obj and obj.type.strip_typedefs().code in (gdb.TYPE_CODE_STRUCT, gdb.TYPE_CODE_UNION):
v = obj[name]
if ftype.code == gdb.TYPE_CODE_INT:
v = hex(int(v))
if (
ftype.code in (gdb.TYPE_CODE_PTR, gdb.TYPE_CODE_ARRAY)
and ftype.target() == pwndbg.typeinfo.uchar
):
data = pwndbg.memory.read(v.address, ftype.sizeof)
v = " ".join("%02x" % b for b in data)
extra = v
# Adjust trailing lines in 'extra' to line up
# This is necessary when there are nested structures.
# Ideally we'd expand recursively if the type is complex.
extra_lines = []
for i, line in enumerate(str(extra).splitlines()):
if i == 0:
extra_lines.append(line)
else:
extra_lines.append(35 * " " + line)
extra = "\n".join(extra_lines)
bitpos = "" if not b else (".%i" % b)
line = " +0x%04x%s %-20s : %s" % (o, bitpos, name, extra)
rv.append(line)
return "\n".join(rv)