1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
# QEMU Monitor Protocol Python class
#
# Copyright (C) 2009, 2010 Red Hat Inc.
#
# Authors:
# Luiz Capitulino <lcapitulino@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
import json
import errno
import socket
import sys
class QMPError(Exception):
pass
class QMPConnectError(QMPError):
pass
class QMPCapabilitiesError(QMPError):
pass
class QMPTimeoutError(QMPError):
pass
class QEMUMonitorProtocol(object):
#: Socket's error class
error = socket.error
#: Socket's timeout
timeout = socket.timeout
def __init__(self, address, server=False, debug=False):
"""
Create a QEMUMonitorProtocol class.
@param address: QEMU address, can be either a unix socket path (string)
or a tuple in the form ( address, port ) for a TCP
connection
@param server: server mode listens on the socket (bool)
@raise socket.error on socket connection errors
@note No connection is established, this is done by the connect() or
accept() methods
"""
self.__events = []
self.__address = address
self._debug = debug
self.__sock = self.__get_sock()
self.__sockfile = None
if server:
self.__sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.__sock.bind(self.__address)
self.__sock.listen(1)
def __get_sock(self):
if isinstance(self.__address, tuple):
family = socket.AF_INET
else:
family = socket.AF_UNIX
return socket.socket(family, socket.SOCK_STREAM)
def __negotiate_capabilities(self):
greeting = self.__json_read()
if greeting is None or "QMP" not in greeting:
raise QMPConnectError
# Greeting seems ok, negotiate capabilities
resp = self.cmd('qmp_capabilities')
if "return" in resp:
return greeting
raise QMPCapabilitiesError
def __json_read(self, only_event=False):
while True:
data = self.__sockfile.readline()
if not data:
return
resp = json.loads(data)
if 'event' in resp:
if self._debug:
print >>sys.stderr, "QMP:<<< %s" % resp
self.__events.append(resp)
if not only_event:
continue
return resp
def __get_events(self, wait=False):
"""
Check for new events in the stream and cache them in __events.
@param wait (bool): block until an event is available.
@param wait (float): If wait is a float, treat it as a timeout value.
@raise QMPTimeoutError: If a timeout float is provided and the timeout
period elapses.
@raise QMPConnectError: If wait is True but no events could be
retrieved or if some other error occurred.
"""
# Check for new events regardless and pull them into the cache:
self.__sock.setblocking(0)
try:
self.__json_read()
except socket.error as err:
if err[0] == errno.EAGAIN:
# No data available
pass
self.__sock.setblocking(1)
# Wait for new events, if needed.
# if wait is 0.0, this means "no wait" and is also implicitly false.
if not self.__events and wait:
if isinstance(wait, float):
self.__sock.settimeout(wait)
try:
ret = self.__json_read(only_event=True)
except socket.timeout:
raise QMPTimeoutError("Timeout waiting for event")
except:
raise QMPConnectError("Error while reading from socket")
if ret is None:
raise QMPConnectError("Error while reading from socket")
self.__sock.settimeout(None)
def connect(self, negotiate=True):
"""
Connect to the QMP Monitor and perform capabilities negotiation.
@return QMP greeting dict
@raise socket.error on socket connection errors
@raise QMPConnectError if the greeting is not received
@raise QMPCapabilitiesError if fails to negotiate capabilities
"""
self.__sock.connect(self.__address)
self.__sockfile = self.__sock.makefile()
if negotiate:
return self.__negotiate_capabilities()
def accept(self):
"""
Await connection from QMP Monitor and perform capabilities negotiation.
@return QMP greeting dict
@raise socket.error on socket connection errors
@raise QMPConnectError if the greeting is not received
@raise QMPCapabilitiesError if fails to negotiate capabilities
"""
self.__sock.settimeout(15)
self.__sock, _ = self.__sock.accept()
self.__sockfile = self.__sock.makefile()
return self.__negotiate_capabilities()
def cmd_obj(self, qmp_cmd):
"""
Send a QMP command to the QMP Monitor.
@param qmp_cmd: QMP command to be sent as a Python dict
@return QMP response as a Python dict or None if the connection has
been closed
"""
if self._debug:
print >>sys.stderr, "QMP:>>> %s" % qmp_cmd
try:
self.__sock.sendall(json.dumps(qmp_cmd))
except socket.error as err:
if err[0] == errno.EPIPE:
return
raise socket.error(err)
resp = self.__json_read()
if self._debug:
print >>sys.stderr, "QMP:<<< %s" % resp
return resp
def cmd(self, name, args=None, cmd_id=None):
"""
Build a QMP command and send it to the QMP Monitor.
@param name: command name (string)
@param args: command arguments (dict)
@param cmd_id: command id (dict, list, string or int)
"""
qmp_cmd = {'execute': name}
if args:
qmp_cmd['arguments'] = args
if cmd_id:
qmp_cmd['id'] = cmd_id
return self.cmd_obj(qmp_cmd)
def command(self, cmd, **kwds):
"""
Build and send a QMP command to the monitor, report errors if any
"""
ret = self.cmd(cmd, kwds)
if "error" in ret:
raise Exception(ret['error']['desc'])
return ret['return']
def pull_event(self, wait=False):
"""
Pulls a single event.
@param wait (bool): block until an event is available.
@param wait (float): If wait is a float, treat it as a timeout value.
@raise QMPTimeoutError: If a timeout float is provided and the timeout
period elapses.
@raise QMPConnectError: If wait is True but no events could be
retrieved or if some other error occurred.
@return The first available QMP event, or None.
"""
self.__get_events(wait)
if self.__events:
return self.__events.pop(0)
return None
def get_events(self, wait=False):
"""
Get a list of available QMP events.
@param wait (bool): block until an event is available.
@param wait (float): If wait is a float, treat it as a timeout value.
@raise QMPTimeoutError: If a timeout float is provided and the timeout
period elapses.
@raise QMPConnectError: If wait is True but no events could be
retrieved or if some other error occurred.
@return The list of available QMP events.
"""
self.__get_events(wait)
return self.__events
def clear_events(self):
"""
Clear current list of pending events.
"""
self.__events = []
def close(self):
self.__sock.close()
self.__sockfile.close()
def settimeout(self, timeout):
self.__sock.settimeout(timeout)
def get_sock_fd(self):
return self.__sock.fileno()
def is_scm_available(self):
return self.__sock.family == socket.AF_UNIX
|
