matos/custom_gdb_extension.py
2020-08-21 00:35:33 +02:00

92 lines
3.1 KiB
Python

from gdb.printing import PrettyPrinter, register_pretty_printer
import gdb
class KthreadPrettyPrinter(object):
def __init__(self, val):
self.val = val
def to_string(self):
result = ""
name = self.val["name"]
state = self.val["state"]
# Should get PC on stack for non-current thread otherwise will only get address in cpu_context_switch
cpuState = self.val["cpuState"]
cmdline = "info line *%s"%int(cpuState["eip"].cast(gdb.lookup_type("long").pointer()))
line = gdb.execute(cmdline, to_string=True)
#line = gdb.find_pc_line(int(cpuState["eip"].cast(gdb.lookup_type("long").pointer()).referenced_value()))
currentThread = gdb.parse_and_eval("currentThread")
if self.val == currentThread:
result += "->"
else:
result += " "
result += "Addr: 0x%x, name: %s, state: %s, PC: %s" % (self.val, name, state, line)
return result
class CustomPrettyPrinterLocator(PrettyPrinter):
"""Given a gdb.Value, search for a custom pretty printer"""
def __init__(self):
super(CustomPrettyPrinterLocator, self).__init__(
"matos_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 = val.type.name
if typename == "kthread":
return KthreadPrettyPrinter(val)
class KthreadListDumpCmd(gdb.Command):
"""Prints the kthread list"""
def __init__(self):
super(KthreadListDumpCmd, self).__init__(
"kthread_list_dump", gdb.COMMAND_USER
)
def _kthread_list_to_str(self, val):
"""Walk through the Kthread list.
We will simply follow the 'next' pointers until we encounter the HEAD again
"""
idx = 0
head = val
kthread_ptr = val
result = ""
while kthread_ptr != 0 and (idx == 0 or kthread_ptr != head) :
result += "\n%d: %s" % (idx, KthreadPrettyPrinter(kthread_ptr).to_string())
kthread_ptr = kthread_ptr["next"]
idx += 1
result = ("Found a Linked List with %d kthread:" % 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
return gdb.COMPLETE_SYMBOL
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)
if args:
kthread_ptr_val = gdb.parse_and_eval(args)
else:
kthread_ptr_val = gdb.parse_and_eval("currentThread")
if str(kthread_ptr_val.type) != "struct kthread *":
print("Expected pointer argument of type (struct kthread *)")
return
print(self._kthread_list_to_str(kthread_ptr_val))
register_pretty_printer(None, CustomPrettyPrinterLocator(), replace=True)
KthreadListDumpCmd()