xref: /openbmc/linux/scripts/gdb/linux/lists.py (revision 671841d2) 
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
14import gdb
15
16from linux import utils
17
18list_head = utils.CachedType("struct list_head")
19hlist_head = utils.CachedType("struct hlist_head")
20hlist_node = utils.CachedType("struct hlist_node")
21
22
23def 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
36def 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
41def 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
54def 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
59def 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
117class 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
131LxListChk()
132