64631f3681
First, this permission never protected a node from being changed, as generic child-replacing functions don't check it. Second, it's a strange thing: it presents a permission of parent node to change its child. But generally, children are replaced by different mechanisms, like jobs or qmp commands, not by nodes. Graph-mod permission is hard to understand. All other permissions describe operations which done by parent node on its child: read, write, resize. Graph modification operations are something completely different. The only place where BLK_PERM_GRAPH_MOD is used as "perm" (not shared perm) is mirror_start_job, for s->target. Still modern code should use bdrv_freeze_backing_chain() to protect from graph modification, if we don't do it somewhere it may be considered as a bug. So, it's a bit risky to drop GRAPH_MOD, and analyzing of possible loss of protection is hard. But one day we should do it, let's do it now. One more bit of information is that locking the corresponding byte in file-posix doesn't make sense at all. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210902093754.2352-1-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
125 lines
3.7 KiB
Python
Executable file
125 lines
3.7 KiB
Python
Executable file
#!/usr/bin/env python3
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#
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# Render Qemu Block Graph
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#
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# Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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import os
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import sys
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import subprocess
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import json
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from graphviz import Digraph
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sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
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from qemu.qmp import (
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QEMUMonitorProtocol,
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QMPResponseError,
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)
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def perm(arr):
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s = 'w' if 'write' in arr else '_'
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s += 'r' if 'consistent-read' in arr else '_'
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s += 'u' if 'write-unchanged' in arr else '_'
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s += 's' if 'resize' in arr else '_'
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return s
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def render_block_graph(qmp, filename, format='png'):
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'''
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Render graph in text (dot) representation into "@filename" and
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representation in @format into "@filename.@format"
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'''
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bds_nodes = qmp.command('query-named-block-nodes')
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bds_nodes = {n['node-name']: n for n in bds_nodes}
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job_nodes = qmp.command('query-block-jobs')
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job_nodes = {n['device']: n for n in job_nodes}
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block_graph = qmp.command('x-debug-query-block-graph')
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graph = Digraph(comment='Block Nodes Graph')
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graph.format = format
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graph.node('permission symbols:\l'
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' w - Write\l'
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' r - consistent-Read\l'
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' u - write - Unchanged\l'
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' g - Graph-mod\l'
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' s - reSize\l'
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'edge label scheme:\l'
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' <child type>\l'
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' <perm>\l'
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' <shared_perm>\l', shape='none')
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for n in block_graph['nodes']:
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if n['type'] == 'block-driver':
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info = bds_nodes[n['name']]
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label = n['name'] + ' [' + info['drv'] + ']'
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if info['drv'] == 'file':
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label += '\n' + os.path.basename(info['file'])
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shape = 'ellipse'
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elif n['type'] == 'block-job':
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info = job_nodes[n['name']]
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label = info['type'] + ' job (' + n['name'] + ')'
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shape = 'box'
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else:
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assert n['type'] == 'block-backend'
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label = n['name'] if n['name'] else 'unnamed blk'
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shape = 'box'
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graph.node(str(n['id']), label, shape=shape)
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for e in block_graph['edges']:
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label = '%s\l%s\l%s\l' % (e['name'], perm(e['perm']),
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perm(e['shared-perm']))
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graph.edge(str(e['parent']), str(e['child']), label=label)
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graph.render(filename)
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class LibvirtGuest():
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def __init__(self, name):
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self.name = name
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def command(self, cmd):
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# only supports qmp commands without parameters
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m = {'execute': cmd}
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ar = ['virsh', 'qemu-monitor-command', self.name, json.dumps(m)]
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reply = json.loads(subprocess.check_output(ar))
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if 'error' in reply:
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raise QMPResponseError(reply)
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return reply['return']
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if __name__ == '__main__':
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obj = sys.argv[1]
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out = sys.argv[2]
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if os.path.exists(obj):
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# assume unix socket
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qmp = QEMUMonitorProtocol(obj)
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qmp.connect()
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else:
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# assume libvirt guest name
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qmp = LibvirtGuest(obj)
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render_block_graph(qmp, out)
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