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
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 = 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
41
42def get_task_by_pid(pid):
43    for task in task_lists():
44        if int(task['pid']) == pid:
45            return task
46    return None
47
48
49class LxTaskByPidFunc(gdb.Function):
50    """Find Linux task by PID and return the task_struct variable.
51
52$lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
53return that task_struct variable which PID matches."""
54
55    def __init__(self):
56        super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
57
58    def invoke(self, pid):
59        task = get_task_by_pid(pid)
60        if task:
61            return task.dereference()
62        else:
63            raise gdb.GdbError("No task of PID " + str(pid))
64
65
66LxTaskByPidFunc()
67
68
69class LxPs(gdb.Command):
70    """Dump Linux tasks."""
71
72    def __init__(self):
73        super(LxPs, self).__init__("lx-ps", gdb.COMMAND_DATA)
74
75    def invoke(self, arg, from_tty):
76        for task in task_lists():
77            gdb.write("{address} {pid} {comm}\n".format(
78                address=task,
79                pid=task["pid"],
80                comm=task["comm"].string()))
81
82LxPs()
83
84
85thread_info_type = utils.CachedType("struct thread_info")
86
87ia64_task_size = None
88
89
90def get_thread_info(task):
91    thread_info_ptr_type = thread_info_type.get_type().pointer()
92    if utils.is_target_arch("ia64"):
93        global ia64_task_size
94        if ia64_task_size is None:
95            ia64_task_size = gdb.parse_and_eval("sizeof(struct task_struct)")
96        thread_info_addr = task.address + ia64_task_size
97        thread_info = thread_info_addr.cast(thread_info_ptr_type)
98    else:
99        thread_info = task['stack'].cast(thread_info_ptr_type)
100    return thread_info.dereference()
101
102
103class LxThreadInfoFunc (gdb.Function):
104    """Calculate Linux thread_info from task variable.
105
106$lx_thread_info(TASK): Given TASK, return the corresponding thread_info
107variable."""
108
109    def __init__(self):
110        super(LxThreadInfoFunc, self).__init__("lx_thread_info")
111
112    def invoke(self, task):
113        return get_thread_info(task)
114
115
116LxThreadInfoFunc()
117