qemu

FORK: QEMU emulator
git clone https://git.neptards.moe/neptards/qemu.git
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render_block_graph.py (3767B)

      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 
     21 import os
     22 import sys
     23 import subprocess
     24 import json
     25 from graphviz import Digraph
     26 
     27 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
     28 from qemu.qmp import QMPError
     29 from qemu.qmp.legacy import QEMUMonitorProtocol
     30 
     31 
     32 def perm(arr):
     33     s = 'w' if 'write' in arr else '_'
     34     s += 'r' if 'consistent-read' in arr else '_'
     35     s += 'u' if 'write-unchanged' in arr else '_'
     36     s += 's' if 'resize' in arr else '_'
     37     return s
     38 
     39 
     40 def 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 
     93 class 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 QMPError(reply)
    106 
    107         return reply['return']
    108 
    109 
    110 if __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)