1#!/usr/bin/env python3
2#
3# Render Qemu Block Graph
4#
5# Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
6#
7# This program is free software; you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation; either version 2 of the License, or
10# (at your option) any later version.
11#
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with this program.  If not, see <http://www.gnu.org/licenses/>.
19#
20
21import os
22import sys
23import subprocess
24import json
25from graphviz import Digraph
26
27sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
28from qemu.qmp import (
29    QEMUMonitorProtocol,
30    QMPResponseError,
31)
32
33
34def perm(arr):
35    s = 'w' if 'write' in arr else '_'
36    s += 'r' if 'consistent-read' in arr else '_'
37    s += 'u' if 'write-unchanged' in arr else '_'
38    s += 's' if 'resize' in arr else '_'
39    return s
40
41
42def render_block_graph(qmp, filename, format='png'):
43    '''
44    Render graph in text (dot) representation into "@filename" and
45    representation in @format into "@filename.@format"
46    '''
47
48    bds_nodes = qmp.command('query-named-block-nodes')
49    bds_nodes = {n['node-name']: n for n in bds_nodes}
50
51    job_nodes = qmp.command('query-block-jobs')
52    job_nodes = {n['device']: n for n in job_nodes}
53
54    block_graph = qmp.command('x-debug-query-block-graph')
55
56    graph = Digraph(comment='Block Nodes Graph')
57    graph.format = format
58    graph.node('permission symbols:\l'
59               '  w - Write\l'
60               '  r - consistent-Read\l'
61               '  u - write - Unchanged\l'
62               '  g - Graph-mod\l'
63               '  s - reSize\l'
64               'edge label scheme:\l'
65               '  <child type>\l'
66               '  <perm>\l'
67               '  <shared_perm>\l', shape='none')
68
69    for n in block_graph['nodes']:
70        if n['type'] == 'block-driver':
71            info = bds_nodes[n['name']]
72            label = n['name'] + ' [' + info['drv'] + ']'
73            if info['drv'] == 'file':
74                label += '\n' + os.path.basename(info['file'])
75            shape = 'ellipse'
76        elif n['type'] == 'block-job':
77            info = job_nodes[n['name']]
78            label = info['type'] + ' job (' + n['name'] + ')'
79            shape = 'box'
80        else:
81            assert n['type'] == 'block-backend'
82            label = n['name'] if n['name'] else 'unnamed blk'
83            shape = 'box'
84
85        graph.node(str(n['id']), label, shape=shape)
86
87    for e in block_graph['edges']:
88        label = '%s\l%s\l%s\l' % (e['name'], perm(e['perm']),
89                                  perm(e['shared-perm']))
90        graph.edge(str(e['parent']), str(e['child']), label=label)
91
92    graph.render(filename)
93
94
95class LibvirtGuest():
96    def __init__(self, name):
97        self.name = name
98
99    def command(self, cmd):
100        # only supports qmp commands without parameters
101        m = {'execute': cmd}
102        ar = ['virsh', 'qemu-monitor-command', self.name, json.dumps(m)]
103
104        reply = json.loads(subprocess.check_output(ar))
105
106        if 'error' in reply:
107            raise QMPResponseError(reply)
108
109        return reply['return']
110
111
112if __name__ == '__main__':
113    obj = sys.argv[1]
114    out = sys.argv[2]
115
116    if os.path.exists(obj):
117        # assume unix socket
118        qmp = QEMUMonitorProtocol(obj)
119        qmp.connect()
120    else:
121        # assume libvirt guest name
122        qmp = LibvirtGuest(obj)
123
124    render_block_graph(qmp, out)
125