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from gdb.printing import PrettyPrinter, register_pretty_printer
import gdb
import uuid
class UuidPrettyPrinter(object):
"""Print 'struct Uuid' as 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'"""
def __init__(self, val):
self.val = val
def to_string(self):
# gdb.Value can be accessed just like they would be in C. Since
# this is a Uuid struct we can index into "bytes" and grab the
# value from each entry in the array
array = self.val["bytes"]
# Format the byte array as a hex string so Python uuid module can
# be used to get the string
uuid_bytes = "".join(
["%02x" % int(array[i]) for i in range(0, array.type.sizeof)]
return str(uuid.UUID(uuid_bytes))
class CustomPrettyPrinterLocator(PrettyPrinter):
"""Given a gdb.Value, search for a custom pretty printer"""
def __init__(self):
super(CustomPrettyPrinterLocator, self).__init__(
"my_pretty_printers", []
def __call__(self, val):
"""Return the custom formatter if the type can be handled"""
typename = gdb.types.get_basic_type(val.type).tag
if typename is None:
typename =
if typename == "Uuid":
return UuidPrettyPrinter(val)
register_pretty_printer(None, CustomPrettyPrinterLocator(), replace=True)
class UuidListDumpCmd(gdb.Command):
"""Prints the ListNode from our example in a nice format!"""
def __init__(self):
super(UuidListDumpCmd, self).__init__(
"uuid_list_dump", gdb.COMMAND_USER
def _uuid_list_to_str(self, val):
"""Walk through the UuidListNode list.
We will simply follow the 'next' pointers until we encounter NULL
idx = 0
node_ptr = val
result = ""
while node_ptr != 0:
uuid = node_ptr["uuid"]
result += "\n%d: Addr: 0x%x, uuid: %s" % (idx, node_ptr, uuid)
node_ptr = node_ptr["next"]
idx += 1
result = ("Found a Linked List with %d nodes:" % idx) + result
return result
def complete(self, text, word):
# We expect the argument passed to be a symbol so fallback to the
# internal tab-completion handler for symbols
def invoke(self, args, from_tty):
# We can pass args here and use Python CLI utilities like argparse
# to do argument parsing
print("Args Passed: %s" % args)
node_ptr_val = gdb.parse_and_eval(args)
if str(node_ptr_val.type) != "UuidListNode *":
print("Expected pointer argument of type (UuidListNode *)")
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