LXR qemu/scripts/render_block

   1#!/usr/bin/env python
   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.machine import MonitorResponseError
  29
  30
  31def perm(arr):
  32    s = 'w' if 'write' in arr else '_'
  33    s += 'r' if 'consistent-read' in arr else '_'
  34    s += 'u' if 'write-unchanged' in arr else '_'
  35    s += 'g' if 'graph-mod' in arr else '_'
  36    s += 's' if 'resize' in arr else '_'
  37    return s
  38
  39
  40def render_block_graph(qmp, filename, format='png'):
  41    '''
  42    Render graph in text (dot) representation into "@filename" and
  43    representation in @format into "@filename.@format"
  44    '''
  45
  46    bds_nodes = qmp.command('query-named-block-nodes')
  47    bds_nodes = {n['node-name']: n for n in bds_nodes}
  48
  49    job_nodes = qmp.command('query-block-jobs')
  50    job_nodes = {n['device']: n for n in job_nodes}
  51
  52    block_graph = qmp.command('x-debug-query-block-graph')
  53
  54    graph = Digraph(comment='Block Nodes Graph')
  55    graph.format = format
  56    graph.node('permission symbols:\l'
  57               '  w - Write\l'
  58               '  r - consistent-Read\l'
  59               '  u - write - Unchanged\l'
  60               '  g - Graph-mod\l'
  61               '  s - reSize\l'
  62               'edge label scheme:\l'
  63               '  <child type>\l'
  64               '  <perm>\l'
  65               '  <shared_perm>\l', shape='none')
  66
  67    for n in block_graph['nodes']:
  68        if n['type'] == 'block-driver':
  69            info = bds_nodes[n['name']]
  70            label = n['name'] + ' [' + info['drv'] + ']'
  71            if info['drv'] == 'file':
  72                label += '\n' + os.path.basename(info['file'])
  73            shape = 'ellipse'
  74        elif n['type'] == 'block-job':
  75            info = job_nodes[n['name']]
  76            label = info['type'] + ' job (' + n['name'] + ')'
  77            shape = 'box'
  78        else:
  79            assert n['type'] == 'block-backend'
  80            label = n['name'] if n['name'] else 'unnamed blk'
  81            shape = 'box'
  82
  83        graph.node(str(n['id']), label, shape=shape)
  84
  85    for e in block_graph['edges']:
  86        label = '%s\l%s\l%s\l' % (e['name'], perm(e['perm']),
  87                                  perm(e['shared-perm']))
  88        graph.edge(str(e['parent']), str(e['child']), label=label)
  89
  90    graph.render(filename)
  91
  92
  93class LibvirtGuest():
  94    def __init__(self, name):
  95        self.name = name
  96
  97    def command(self, cmd):
  98        # only supports qmp commands without parameters
  99        m = {'execute': cmd}
 100        ar = ['virsh', 'qemu-monitor-command', self.name, json.dumps(m)]
 101
 102        reply = json.loads(subprocess.check_output(ar))
 103
 104        if 'error' in reply:
 105            raise MonitorResponseError(reply)
 106
 107        return reply['return']
 108
 109
 110if __name__ == '__main__':
 111    obj = sys.argv[1]
 112    out = sys.argv[2]
 113
 114    if os.path.exists(obj):
 115        # assume unix socket
 116        qmp = QEMUMonitorProtocol(obj)
 117        qmp.connect()
 118    else:
 119        # assume libvirt guest name
 120        qmp = LibvirtGuest(obj)
 121
 122    render_block_graph(qmp, out)
 123