scripts/gdb/linux/lists.py

   1 #
   2 # gdb helper commands and functions for Linux kernel debugging
   3 #
   4 #  list tools
   5 #
   6 # Copyright (c) Thiebaud Weksteen, 2015
   7 #
   8 # Authors:
   9 #  Thiebaud Weksteen <thiebaud@weksteen.fr>
  10 #
  11 # This work is licensed under the terms of the GNU GPL version 2.
  12 #
  13
  14 import gdb
  15
  16 from linux import utils
  17
  18 list_head = utils.CachedType("struct list_head")
  19 hlist_head = utils.CachedType("struct hlist_head")
  20 hlist_node = utils.CachedType("struct hlist_node")
  21
  22
  23 def list_for_each(head):
  24     if head.type == list_head.get_type().pointer():
  25         head = head.dereference()
  26     elif head.type != list_head.get_type():
  27         raise TypeError("Must be struct list_head not {}"
  28                            .format(head.type))
  29
  30     node = head['next'].dereference()
  31     while node.address != head.address:
  32         yield node.address
  33         node = node['next'].dereference()
  34
  35
  36 def list_for_each_entry(head, gdbtype, member):
  37     for node in list_for_each(head):
  38         yield utils.container_of(node, gdbtype, member)
  39
  40
  41 def hlist_for_each(head):
  42     if head.type == hlist_head.get_type().pointer():
  43         head = head.dereference()
  44     elif head.type != hlist_head.get_type():
  45         raise TypeError("Must be struct hlist_head not {}"
  46                            .format(head.type))
  47
  48     node = head['first'].dereference()
  49     while node.address:
  50         yield node.address
  51         node = node['next'].dereference()
  52
  53
  54 def hlist_for_each_entry(head, gdbtype, member):
  55     for node in hlist_for_each(head):
  56         yield utils.container_of(node, gdbtype, member)
  57
  58
  59 def list_check(head):
  60     nb = 0
  61     if (head.type == list_head.get_type().pointer()):
  62         head = head.dereference()
  63     elif (head.type != list_head.get_type()):
  64         raise gdb.GdbError('argument must be of type (struct list_head [*])')
  65     c = head
  66     try:
  67         gdb.write("Starting with: {}\n".format(c))
  68     except gdb.MemoryError:
  69         gdb.write('head is not accessible\n')
  70         return
  71     while True:
  72         p = c['prev'].dereference()
  73         n = c['next'].dereference()
  74         try:
  75             if p['next'] != c.address:
  76                 gdb.write('prev.next != current: '
  77                           'current@{current_addr}={current} '
  78                           'prev@{p_addr}={p}\n'.format(
  79                               current_addr=c.address,
  80                               current=c,
  81                               p_addr=p.address,
  82                               p=p,
  83                           ))
  84                 return
  85         except gdb.MemoryError:
  86             gdb.write('prev is not accessible: '
  87                       'current@{current_addr}={current}\n'.format(
  88                           current_addr=c.address,
  89                           current=c
  90                       ))
  91             return
  92         try:
  93             if n['prev'] != c.address:
  94                 gdb.write('next.prev != current: '
  95                           'current@{current_addr}={current} '
  96                           'next@{n_addr}={n}\n'.format(
  97                               current_addr=c.address,
  98                               current=c,
  99                               n_addr=n.address,
 100                               n=n,
 101                           ))
 102                 return
 103         except gdb.MemoryError:
 104             gdb.write('next is not accessible: '
 105                       'current@{current_addr}={current}\n'.format(
 106                           current_addr=c.address,
 107                           current=c
 108                       ))
 109             return
 110         c = n
 111         nb += 1
 112         if c == head:
 113             gdb.write("list is consistent: {} node(s)\n".format(nb))
 114             return
 115
 116
 117 class LxListChk(gdb.Command):
 118     """Verify a list consistency"""
 119
 120     def __init__(self):
 121         super(LxListChk, self).__init__("lx-list-check", gdb.COMMAND_DATA,
 122                                         gdb.COMPLETE_EXPRESSION)
 123
 124     def invoke(self, arg, from_tty):
 125         argv = gdb.string_to_argv(arg)
 126         if len(argv) != 1:
 127             raise gdb.GdbError("lx-list-check takes one argument")
 128         list_check(gdb.parse_and_eval(argv[0]))
 129
 130
 131 LxListChk()