1#
2# gdb helper commands and functions for Linux kernel debugging
3#
4#  task & thread tools
5#
6# Copyright (c) Siemens AG, 2011-2013
7#
8# Authors:
9#  Jan Kiszka <jan.kiszka@siemens.com>
10#
11# This work is licensed under the terms of the GNU GPL version 2.
12#
13
14import gdb
15
16from linux import utils, lists
17
18
19task_type = utils.CachedType("struct task_struct")
20
21
22def task_lists():
23    task_ptr_type = task_type.get_type().pointer()
24    init_task = gdb.parse_and_eval("init_task").address
25    t = init_task
26
27    while True:
28        thread_head = t['signal']['thread_head']
29        for thread in lists.list_for_each_entry(thread_head, task_ptr_type, 'thread_node'):
30            yield thread
31
32        t = utils.container_of(t['tasks']['next'],
33                               task_ptr_type, "tasks")
34        if t == init_task:
35            return
36
37
38def get_task_by_pid(pid):
39    for task in task_lists():
40        if int(task['pid']) == pid:
41            return task
42    return None
43
44
45class LxTaskByPidFunc(gdb.Function):
46    """Find Linux task by PID and return the task_struct variable.
47
48$lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
49return that task_struct variable which PID matches."""
50
51    def __init__(self):
52        super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
53
54    def invoke(self, pid):
55        task = get_task_by_pid(pid)
56        if task:
57            return task.dereference()
58        else:
59            raise gdb.GdbError("No task of PID " + str(pid))
60
61
62LxTaskByPidFunc()
63
64
65class LxPs(gdb.Command):
66    """Dump Linux tasks."""
67
68    def __init__(self):
69        super(LxPs, self).__init__("lx-ps", gdb.COMMAND_DATA)
70
71    def invoke(self, arg, from_tty):
72        gdb.write("{:>10} {:>12} {:>7}\n".format("TASK", "PID", "COMM"))
73        for task in task_lists():
74            gdb.write("{} {:^5} {}\n".format(
75                task.format_string().split()[0],
76                task["pid"].format_string(),
77                task["comm"].string()))
78
79
80LxPs()
81
82
83thread_info_type = utils.CachedType("struct thread_info")
84
85
86def get_thread_info(task):
87    thread_info_ptr_type = thread_info_type.get_type().pointer()
88    if task.type.fields()[0].type == thread_info_type.get_type():
89        return task['thread_info']
90    thread_info = task['stack'].cast(thread_info_ptr_type)
91    return thread_info.dereference()
92
93
94class LxThreadInfoFunc (gdb.Function):
95    """Calculate Linux thread_info from task variable.
96
97$lx_thread_info(TASK): Given TASK, return the corresponding thread_info
98variable."""
99
100    def __init__(self):
101        super(LxThreadInfoFunc, self).__init__("lx_thread_info")
102
103    def invoke(self, task):
104        return get_thread_info(task)
105
106
107LxThreadInfoFunc()
108
109
110class LxThreadInfoByPidFunc (gdb.Function):
111    """Calculate Linux thread_info from task variable found by pid
112
113$lx_thread_info_by_pid(PID): Given PID, return the corresponding thread_info
114variable."""
115
116    def __init__(self):
117        super(LxThreadInfoByPidFunc, self).__init__("lx_thread_info_by_pid")
118
119    def invoke(self, pid):
120        task = get_task_by_pid(pid)
121        if task:
122            return get_thread_info(task.dereference())
123        else:
124            raise gdb.GdbError("No task of PID " + str(pid))
125
126
127LxThreadInfoByPidFunc()
128