#
# gdb helper commands and functions for Linux kernel debugging
#
# list tools
#
# Copyright (c) Thiebaud Weksteen, 2015
#
# Authors:
# Thiebaud Weksteen <thiebaud@weksteen.fr>
#
# This work is licensed under the terms of the GNU GPL version 2.
#
import gdb
from linux import utils
list_head = utils.CachedType("struct list_head")
def list_check(head):
nb = 0
if (head.type == list_head.get_type().pointer()):
head = head.dereference()
elif (head.type != list_head.get_type()):
raise gdb.GdbError('argument must be of type (struct list_head [*])')
c = head
try:
gdb.write("Starting with: {}\n".format(c))
except gdb.MemoryError:
gdb.write('head is not accessible\n')
return
while True:
p = c['prev'].dereference()
n = c['next'].dereference()
try:
if p['next'] != c.address:
gdb.write('prev.next != current: '
'current@{current_addr}={current} '
'prev@{p_addr}={p}\n'.format(
current_addr=c.address,
current=c,
p_addr=p.address,
p=p,
))
return
except gdb.MemoryError:
gdb.write('prev is not accessible: '
'current@{current_addr}={current}\n'.format(
current_addr=c.address,
current=c
))
return
try:
if n['prev'] != c.address:
gdb.write('next.prev != current: '
'current@{current_addr}={current} '
'next@{n_addr}={n}\n'.format(
current_addr=c.address,
current=c,
n_addr=n.address,
n=n,
))
return
except gdb.MemoryError:
gdb.write('next is not accessible: '
'current@{current_addr}={current}\n'.format(
current_addr=c.address,
current=c
))
return
c = n
nb += 1
if c == head:
gdb.write("list is consistent: {} node(s)\n".format(nb))
return
class LxListChk(gdb.Command):
"""Verify a list consistency"""
def __init__(self):
super(LxListChk, self).__init__("lx-list-check", gdb.COMMAND_DATA,
gdb.COMPLETE_EXPRESSION)
def invoke(self, arg, from_tty):
argv = gdb.string_to_argv(arg)
if len(argv) != 1:
raise gdb.GdbError("lx-list-check takes one argument")
list_check(gdb.parse_and_eval(argv[0]))
LxListChk()