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
17
18
19task_type = utils.CachedType("struct task_struct")
20
21def task_lists():
22    global task_type
23    task_ptr_type = task_type.get_type().pointer()
24    init_task = gdb.parse_and_eval("init_task").address
25    t = g = init_task
26
27    while True:
28        while True:
29            yield t
30
31            t = utils.container_of(t['thread_group']['next'],
32                                   task_ptr_type, "thread_group")
33            if t == g:
34                break
35
36        t = g = utils.container_of(g['tasks']['next'],
37                                   task_ptr_type, "tasks")
38        if t == init_task:
39            return
40
41def get_task_by_pid(pid):
42    for task in task_lists():
43        if int(task['pid']) == pid:
44            return task
45    return None
46
47
48class LxTaskByPidFunc(gdb.Function):
49    """Find Linux task by PID and return the task_struct variable.
50
51$lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
52return that task_struct variable which PID matches."""
53
54    def __init__(self):
55        super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
56
57    def invoke(self, pid):
58        task = get_task_by_pid(pid)
59        if task:
60            return task.dereference()
61        else:
62            raise gdb.GdbError("No task of PID " + str(pid))
63
64
65LxTaskByPidFunc()
66
67
68thread_info_type = utils.CachedType("struct thread_info")
69
70ia64_task_size = None
71
72
73def get_thread_info(task):
74    global thread_info_type
75    thread_info_ptr_type = thread_info_type.get_type().pointer()
76    if utils.is_target_arch("ia64"):
77        global ia64_task_size
78        if ia64_task_size is None:
79            ia64_task_size = gdb.parse_and_eval("sizeof(struct task_struct)")
80        thread_info_addr = task.address + ia64_task_size
81        thread_info = thread_info_addr.cast(thread_info_ptr_type)
82    else:
83        thread_info = task['stack'].cast(thread_info_ptr_type)
84    return thread_info.dereference()
85
86
87class LxThreadInfoFunc (gdb.Function):
88    """Calculate Linux thread_info from task variable.
89
90$lx_thread_info(TASK): Given TASK, return the corresponding thread_info
91variable."""
92
93    def __init__(self):
94        super(LxThreadInfoFunc, self).__init__("lx_thread_info")
95
96    def invoke(self, task):
97        return get_thread_info(task)
98
99
100LxThreadInfoFunc()
101