--- /dev/null
+===================
+virt-qemu-qmp-proxy
+===================
+
+--------------------------------------------------
+Expose a QMP proxy server for a libvirt QEMU guest
+--------------------------------------------------
+
+:Manual section: 1
+:Manual group: Virtualization Support
+
+.. contents::
+
+
+SYNOPSIS
+========
+
+``virt-qemu-qmp-proxy`` [*OPTION*]... *DOMAIN* *QMP-SOCKET-PATH*
+
+
+DESCRIPTION
+===========
+
+This tool provides a way to expose a QMP proxy server that communicates
+with a QEMU guest managed by libvirt. This enables standard QMP client
+tools to interact with libvirt managed guests.
+
+**NOTE: use of this tool will result in the running QEMU guest being
+marked as tainted.** It is strongly recommended that this tool *only be
+used to send commands which query information* about the running guest.
+If this tool is used to make changes to the state of the guest, this
+may have negative interactions with the QEMU driver, resulting in an
+inability to manage the guest operation thereafter, and in the worst
+case **potentially lead to data loss or corruption**.
+
+The ``virt-qemu-qmp-proxy`` program will listen on a UNIX socket for incoming
+client connections, and run the QMP protocol over the connection. Any
+commands received will be sent to the running libvirt guest, and replies
+sent back.
+
+The ``virt-qemu-qmp-proxy`` program may be interrupted (eg Ctrl-C) when it
+is no longer required. The libvirt QEMU guest will continue running.
+
+
+OPTIONS
+=======
+
+*DOMAIN*
+
+The ID or UUID or Name of the libvirt QEMU guest.
+
+*QMP-SOCKET-PATH*
+
+The filesystem path at which to run the QMP server, listening for
+incoming connections.
+
+``-c`` *CONNECTION-URI*
+``--connect``\ =\ *CONNECTION-URI*
+
+The URI for the connection to the libvirt QEMU driver. If omitted,
+a URI will be auto-detected.
+
+``-v``, ``--verbose``
+
+Run in verbose mode, printing all QMP commands and replies that
+are handled.
+
+``-h``, ``--help``
+
+Display the command line help.
+
+
+EXIT STATUS
+===========
+
+Upon successful shutdown, an exit status of 0 will be set. Upon
+failure a non-zero status will be set.
+
+
+AUTHOR
+======
+
+Daniel P. Berrangé
+
+
+BUGS
+====
+
+Please report all bugs you discover. This should be done via either:
+
+#. the mailing list
+
+ `https://libvirt.org/contact.html <https://libvirt.org/contact.html>`_
+
+#. the bug tracker
+
+ `https://libvirt.org/bugs.html <https://libvirt.org/bugs.html>`_
+
+Alternatively, you may report bugs to your software distributor / vendor.
+
+COPYRIGHT
+=========
+
+Copyright (C) 2022 by Red Hat, Inc.
+
+
+LICENSE
+=======
+
+``virt-qemu-qmp-proxy`` is distributed under the terms of the GNU LGPL v2+.
+This is free software; see the source for copying conditions. There
+is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
+PURPOSE
+
+
+SEE ALSO
+========
+
+virsh(1), `https://libvirt.org/ <https://libvirt.org/>`_,
+`QMP reference <https://www.qemu.org/docs/master/interop/qemu-qmp-ref.html>`_
--- /dev/null
+#!/usr/bin/env python3
+
+import argparse
+import array
+import libvirt
+import libvirt_qemu
+import os
+import re
+import socket
+import sys
+import traceback
+import json
+import fcntl
+
+
+debug = False
+
+
+def get_domain(uri, domstr):
+ conn = libvirt.open(uri)
+
+ dom = None
+ saveex = None
+
+ def try_lookup(cb):
+ try:
+ return cb()
+ except libvirt.libvirtError as ex:
+ nonlocal saveex
+ if saveex is None:
+ saveex = ex
+
+ if re.match(r'^\d+$', domstr):
+ dom = try_lookup(lambda: conn.lookupByID(int(domstr)))
+
+ if dom is None and re.match(r'^[-a-f0-9]{36}|[a-f0-9]{32}$', domstr):
+ dom = try_lookup(lambda: conn.lookupByUUIDString(domstr))
+
+ if dom is None:
+ dom = try_lookup(lambda: conn.lookupByName(domstr))
+
+ if dom is None:
+ raise saveex
+
+ if not dom.isActive():
+ raise Exception("Domain must be running to use QMP")
+
+ return conn, dom
+
+
+class QMPProxy(object):
+
+ def __init__(self, conn, dom, serversock, verbose):
+ self.conn = conn
+ self.dom = dom
+ self.verbose = verbose
+
+ self.serversock = serversock
+ self.serverwatch = 0
+
+ self.clientsock = None
+ self.clientwatch = 0
+
+ self.api2sock = bytes([])
+ self.api2sockfds = []
+
+ self.sock2api = bytes([])
+ self.sock2apifds = []
+
+ self.serverwatch = libvirt.virEventAddHandle(
+ self.serversock.fileno(), libvirt.VIR_EVENT_HANDLE_READABLE,
+ self.handle_server_io, self)
+
+ libvirt_qemu.qemuMonitorEventRegister(self.conn, self.dom,
+ None,
+ self.handle_qmp_event,
+ self)
+
+ @staticmethod
+ def handle_qmp_event(conn, dom, event, secs, usecs, details, self):
+ evdoc = {
+ "event": event,
+ "timestamp": {"seconds": secs, "microseconds": usecs}
+ }
+ if details is not None:
+ evdoc["data"] = details
+
+ ev = json.dumps(evdoc)
+ if self.verbose:
+ print(ev)
+ ev += "\r\n"
+ self.api2sock += ev.encode("utf-8")
+ self.update_client_events()
+
+ def recv_with_fds(self):
+ # Match VIR_NET_MESSAGE_NUM_FDS_MAX in virnetprotocol.x
+ maxfds = 32
+ fds = array.array('i')
+ cmsgdatalen = socket.CMSG_LEN(maxfds * fds.itemsize)
+
+ data, cmsgdata, flags, addr = self.clientsock.recvmsg(1024,
+ cmsgdatalen)
+ for cmsg_level, cmsg_type, cmsg_data in cmsgdata:
+ scm_rights = (cmsg_level == socket.SOL_SOCKET and
+ cmsg_type == socket.SCM_RIGHTS)
+ if scm_rights:
+ fds.frombytes(cmsg_data[:len(cmsg_data) -
+ (len(cmsg_data) % fds.itemsize)])
+ else:
+ raise Exception("Unexpected CMSGDATA level %d type %d" % (
+ cmsg_level, cmsg_type))
+
+ return data, [self.make_file(fd) for fd in fds]
+
+ def send_with_fds(self, data, fds):
+ cfds = [fd.fileno() for fd in fds]
+
+ cmsgdata = [(socket.SOL_SOCKET, socket.SCM_RIGHTS,
+ array.array("i", cfds))]
+
+ return self.clientsock.sendmsg([data], cmsgdata)
+
+ @staticmethod
+ def make_file(fd):
+ flags = fcntl.fcntl(fd, fcntl.F_GETFL)
+
+ mask = os.O_RDONLY | os.O_WRONLY | os.O_RDWR | os.O_APPEND
+ flags = flags & mask
+ mode = ""
+ if flags == os.O_RDONLY:
+ mode = "rb"
+ elif flags == os.O_WRONLY:
+ mode = "wb"
+ elif flags == os.O_RDWR:
+ mode = "r+b"
+ elif flags == (os.O_WRONLY | os.O_APPEND):
+ mode = "ab"
+ elif flags == (os.O_RDWR | os.O_APPEND):
+ mode = "a+b"
+
+ return os.fdopen(fd, mode)
+
+ def add_client(self, sock):
+ ver = self.conn.getVersion()
+ major = int(ver / 1000000) % 1000
+ minor = int(ver / 1000) % 1000
+ micro = ver % 1000
+
+ greetingobj = {
+ "QMP": {
+ "version": {
+ "qemu": {
+ "major": major,
+ "minor": minor,
+ "micro": micro,
+ },
+ "package": f"qemu-{major}.{minor}.{micro}",
+ },
+ "capabilities": [
+ "oob"
+ ],
+ }
+ }
+ greeting = json.dumps(greetingobj)
+ if self.verbose:
+ print(greeting)
+ greeting += "\r\n"
+
+ self.clientsock = sock
+ self.clientwatch = libvirt.virEventAddHandle(
+ self.clientsock.fileno(), libvirt.VIR_EVENT_HANDLE_WRITABLE,
+ self.handle_client_io, self)
+ self.api2sock += greeting.encode("utf-8")
+ self.update_server_events()
+
+ def remove_client(self):
+ libvirt.virEventRemoveHandle(self.clientwatch)
+ self.clientsock.close()
+ self.clientsock = None
+ self.clientwatch = 0
+ self.update_server_events()
+
+ self.api2sock = bytes([])
+ self.api2sockfds = []
+
+ self.sock2api = bytes([])
+ self.sock2apifds = []
+
+ def update_client_events(self):
+ # For simplicity of tracking distinct QMP cmds and their passed FDs
+ # we don't try to support "pipelining", only a single cmd may be
+ # inflight
+ if len(self.api2sock) > 0:
+ events = libvirt.VIR_EVENT_HANDLE_WRITABLE
+ else:
+ events = libvirt.VIR_EVENT_HANDLE_READABLE
+
+ libvirt.virEventUpdateHandle(self.clientwatch, events)
+
+ def update_server_events(self):
+ if self.clientsock is not None:
+ libvirt.virEventUpdateHandle(self.serverwatch, 0)
+ else:
+ libvirt.virEventUpdateHandle(self.serverwatch,
+ libvirt.VIR_EVENT_HANDLE_READABLE)
+
+ def try_command(self):
+ try:
+ cmdstr = self.sock2api.decode("utf-8")
+ cmd = json.loads(cmdstr)
+
+ if self.verbose:
+ cmdstr = cmdstr.strip()
+ print(cmdstr)
+ except Exception as ex:
+ if debug:
+ print("Incomplete %s: %s" % (self.sock2api, ex))
+ return
+
+ id = None
+ if "id" in cmd:
+ id = cmd["id"]
+ del cmd["id"]
+
+ if cmd.get("execute", "") == "qmp_capabilities":
+ resobj = {
+ "return": {},
+ }
+ resfds = []
+ else:
+ if hasattr(libvirt_qemu, "qemuMonitorCommandWithFiles"):
+ res, resfds = libvirt_qemu.qemuMonitorCommandWithFiles(
+ self.dom, json.dumps(cmd), [f.fileno() for f in self.sock2apifds])
+ resobj = json.loads(res)
+ else:
+ if len(self.sock2apifds) > 0:
+ raise Exception("FD passing not supported")
+ res = libvirt_qemu.qemuMonitorCommand(
+ self.dom, json.dumps(cmd))
+ resfds = []
+ resobj = json.loads(res)
+
+ if "id" in resobj:
+ del resobj["id"]
+ if id is not None:
+ resobj["id"] = id
+
+ res = json.dumps(resobj)
+ if self.verbose:
+ print(res)
+ res += "\r\n"
+
+ self.sock2api = bytes([])
+ self.sock2apifds = []
+ self.api2sock += res.encode("utf-8")
+ self.api2sockfds = resfds
+
+ @staticmethod
+ def handle_client_io(watch, fd, events, self):
+ error = False
+ try:
+ if events & libvirt.VIR_EVENT_HANDLE_WRITABLE:
+ done = self.send_with_fds(self.api2sock, self.api2sockfds)
+ if done > 0:
+ self.api2sock = self.api2sock[done:]
+ self.api2sockfds = []
+ elif events & libvirt.VIR_EVENT_HANDLE_READABLE:
+ data, fds = self.recv_with_fds()
+ if len(data) == 0:
+ error = True
+ else:
+ self.sock2api += data
+ if len(fds):
+ self.sock2apifds += fds
+
+ self.try_command()
+ else:
+ error = True
+ except Exception as e:
+ global debug
+ if debug:
+ print("%s: %s" % (sys.argv[0], str(e)))
+ print(traceback.format_exc())
+ error = True
+
+ if error:
+ self.remove_client()
+ else:
+ self.update_client_events()
+
+ @staticmethod
+ def handle_server_io(watch, fd, events, self):
+ if self.clientsock is None:
+ sock, addr = self.serversock.accept()
+ self.add_client(sock)
+ else:
+ self.update_server_events()
+
+
+def parse_commandline():
+ parser = argparse.ArgumentParser(description="Libvirt QMP proxy")
+ parser.add_argument("--connect", "-c",
+ help="Libvirt QEMU driver connection URI")
+ parser.add_argument("--debug", "-d", action='store_true',
+ help="Display debugging information")
+ parser.add_argument("--verbose", "-v", action='store_true',
+ help="Display QMP traffic")
+ parser.add_argument("domain", metavar="DOMAIN",
+ help="Libvirt guest domain ID/UUID/Name")
+ parser.add_argument("sockpath", metavar="QMP-SOCK-PATH",
+ help="UNIX socket path for QMP server")
+
+ return parser.parse_args()
+
+
+def main():
+ args = parse_commandline()
+ global debug
+ debug = args.debug
+
+ if not debug:
+ libvirt.registerErrorHandler(lambda opaque, error: None, None)
+
+ libvirt.virEventRegisterDefaultImpl()
+
+ conn, dom = get_domain(args.connect, args.domain)
+
+ if conn.getType() != "QEMU":
+ raise Exception("QMP proxy requires a QEMU driver connection not %s" %
+ conn.getType())
+
+ sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+ if os.path.exists(args.sockpath):
+ os.unlink(args.sockpath)
+ sock.bind(args.sockpath)
+ sock.listen(1)
+
+ _ = QMPProxy(conn, dom, sock, args.verbose)
+
+ while True:
+ libvirt.virEventRunDefaultImpl()
+
+
+try:
+ main()
+ sys.exit(0)
+except Exception as e:
+ print("%s: %s" % (sys.argv[0], str(e)))
+ if debug:
+ print(traceback.format_exc())
+ sys.exit(1)
projects / libvirt.git / commitdiff