scripts/qemu.py

   1 # QEMU library
   2 #
   3 # Copyright (C) 2015-2016 Red Hat Inc.
   4 # Copyright (C) 2012 IBM Corp.
   5 #
   6 # Authors:
   7 #  Fam Zheng <famz@redhat.com>
   8 #
   9 # This work is licensed under the terms of the GNU GPL, version 2.  See
  10 # the COPYING file in the top-level directory.
  11 #
  12 # Based on qmp.py.
  13 #
  14
  15 import errno
  16 import logging
  17 import os
  18 import sys
  19 import subprocess
  20 import qmp.qmp
  21
  22
  23 LOG = logging.getLogger(__name__)
  24
  25
  26 class QEMUMachineError(Exception):
  27     """
  28     Exception called when an error in QEMUMachine happens.
  29     """
  30
  31
  32 class MonitorResponseError(qmp.qmp.QMPError):
  33     '''
  34     Represents erroneous QMP monitor reply
  35     '''
  36     def __init__(self, reply):
  37         try:
  38             desc = reply["error"]["desc"]
  39         except KeyError:
  40             desc = reply
  41         super(MonitorResponseError, self).__init__(desc)
  42         self.reply = reply
  43
  44
  45 class QEMUMachine(object):
  46     '''A QEMU VM
  47
  48     Use this object as a context manager to ensure the QEMU process terminates::
  49
  50         with VM(binary) as vm:
  51             ...
  52         # vm is guaranteed to be shut down here
  53     '''
  54
  55     def __init__(self, binary, args=None, wrapper=None, name=None,
  56                  test_dir="/var/tmp", monitor_address=None,
  57                  socket_scm_helper=None, debug=False):
  58         '''
  59         Initialize a QEMUMachine
  60
  61         @param binary: path to the qemu binary
  62         @param args: list of extra arguments
  63         @param wrapper: list of arguments used as prefix to qemu binary
  64         @param name: prefix for socket and log file names (default: qemu-PID)
  65         @param test_dir: where to create socket and log file
  66         @param monitor_address: address for QMP monitor
  67         @param socket_scm_helper: helper program, required for send_fd_scm()"
  68         @param debug: enable debug mode
  69         @note: Qemu process is not started until launch() is used.
  70         '''
  71         if args is None:
  72             args = []
  73         if wrapper is None:
  74             wrapper = []
  75         if name is None:
  76             name = "qemu-%d" % os.getpid()
  77         if monitor_address is None:
  78             monitor_address = os.path.join(test_dir, name + "-monitor.sock")
  79         self._monitor_address = monitor_address
  80         self._qemu_log_path = os.path.join(test_dir, name + ".log")
  81         self._popen = None
  82         self._binary = binary
  83         self._args = list(args)     # Force copy args in case we modify them
  84         self._wrapper = wrapper
  85         self._events = []
  86         self._iolog = None
  87         self._socket_scm_helper = socket_scm_helper
  88         self._debug = debug
  89         self._qmp = None
  90
  91     def __enter__(self):
  92         return self
  93
  94     def __exit__(self, exc_type, exc_val, exc_tb):
  95         self.shutdown()
  96         return False
  97
  98     # This can be used to add an unused monitor instance.
  99     def add_monitor_telnet(self, ip, port):
 100         args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)
 101         self._args.append('-monitor')
 102         self._args.append(args)
 103
 104     def add_fd(self, fd, fdset, opaque, opts=''):
 105         '''Pass a file descriptor to the VM'''
 106         options = ['fd=%d' % fd,
 107                    'set=%d' % fdset,
 108                    'opaque=%s' % opaque]
 109         if opts:
 110             options.append(opts)
 111
 112         self._args.append('-add-fd')
 113         self._args.append(','.join(options))
 114         return self
 115
 116     def send_fd_scm(self, fd_file_path):
 117         # In iotest.py, the qmp should always use unix socket.
 118         assert self._qmp.is_scm_available()
 119         if self._socket_scm_helper is None:
 120             raise QEMUMachineError("No path to socket_scm_helper set")
 121         if not os.path.exists(self._socket_scm_helper):
 122             raise QEMUMachineError("%s does not exist" %
 123                                    self._socket_scm_helper)
 124         fd_param = ["%s" % self._socket_scm_helper,
 125                     "%d" % self._qmp.get_sock_fd(),
 126                     "%s" % fd_file_path]
 127         devnull = open('/dev/null', 'rb')
 128         proc = subprocess.Popen(fd_param, stdin=devnull, stdout=subprocess.PIPE,
 129                                 stderr=subprocess.STDOUT)
 130         output = proc.communicate()[0]
 131         if output:
 132             LOG.debug(output)
 133
 134         return proc.returncode
 135
 136     @staticmethod
 137     def _remove_if_exists(path):
 138         '''Remove file object at path if it exists'''
 139         try:
 140             os.remove(path)
 141         except OSError as exception:
 142             if exception.errno == errno.ENOENT:
 143                 return
 144             raise
 145
 146     def is_running(self):
 147         return self._popen is not None and self._popen.returncode is None
 148
 149     def exitcode(self):
 150         if self._popen is None:
 151             return None
 152         return self._popen.returncode
 153
 154     def get_pid(self):
 155         if not self.is_running():
 156             return None
 157         return self._popen.pid
 158
 159     def _load_io_log(self):
 160         with open(self._qemu_log_path, "r") as iolog:
 161             self._iolog = iolog.read()
 162
 163     def _base_args(self):
 164         if isinstance(self._monitor_address, tuple):
 165             moncdev = "socket,id=mon,host=%s,port=%s" % (
 166                 self._monitor_address[0],
 167                 self._monitor_address[1])
 168         else:
 169             moncdev = 'socket,id=mon,path=%s' % self._monitor_address
 170         return ['-chardev', moncdev,
 171                 '-mon', 'chardev=mon,mode=control',
 172                 '-display', 'none', '-vga', 'none']
 173
 174     def _pre_launch(self):
 175         self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address,
 176                                                 server=True,
 177                                                 debug=self._debug)
 178
 179     def _post_launch(self):
 180         self._qmp.accept()
 181
 182     def _post_shutdown(self):
 183         if not isinstance(self._monitor_address, tuple):
 184             self._remove_if_exists(self._monitor_address)
 185         self._remove_if_exists(self._qemu_log_path)
 186
 187     def launch(self):
 188         '''Launch the VM and establish a QMP connection'''
 189         devnull = open('/dev/null', 'rb')
 190         qemulog = open(self._qemu_log_path, 'wb')
 191         try:
 192             self._pre_launch()
 193             args = (self._wrapper + [self._binary] + self._base_args() +
 194                     self._args)
 195             self._popen = subprocess.Popen(args, stdin=devnull, stdout=qemulog,
 196                                            stderr=subprocess.STDOUT,
 197                                            shell=False)
 198             self._post_launch()
 199         except:
 200             if self.is_running():
 201                 self._popen.kill()
 202                 self._popen.wait()
 203             self._load_io_log()
 204             self._post_shutdown()
 205             raise
 206
 207     def shutdown(self):
 208         '''Terminate the VM and clean up'''
 209         if self.is_running():
 210             try:
 211                 self._qmp.cmd('quit')
 212                 self._qmp.close()
 213             except:
 214                 self._popen.kill()
 215
 216             exitcode = self._popen.wait()
 217             if exitcode < 0:
 218                 LOG.warn('qemu received signal %i: %s', -exitcode,
 219                           ' '.join(self._args))
 220             self._load_io_log()
 221             self._post_shutdown()
 222
 223     def qmp(self, cmd, conv_keys=True, **args):
 224         '''Invoke a QMP command and return the response dict'''
 225         qmp_args = dict()
 226         for key, value in args.iteritems():
 227             if conv_keys:
 228                 qmp_args[key.replace('_', '-')] = value
 229             else:
 230                 qmp_args[key] = value
 231
 232         return self._qmp.cmd(cmd, args=qmp_args)
 233
 234     def command(self, cmd, conv_keys=True, **args):
 235         '''
 236         Invoke a QMP command.
 237         On success return the response dict.
 238         On failure raise an exception.
 239         '''
 240         reply = self.qmp(cmd, conv_keys, **args)
 241         if reply is None:
 242             raise qmp.qmp.QMPError("Monitor is closed")
 243         if "error" in reply:
 244             raise MonitorResponseError(reply)
 245         return reply["return"]
 246
 247     def get_qmp_event(self, wait=False):
 248         '''Poll for one queued QMP events and return it'''
 249         if len(self._events) > 0:
 250             return self._events.pop(0)
 251         return self._qmp.pull_event(wait=wait)
 252
 253     def get_qmp_events(self, wait=False):
 254         '''Poll for queued QMP events and return a list of dicts'''
 255         events = self._qmp.get_events(wait=wait)
 256         events.extend(self._events)
 257         del self._events[:]
 258         self._qmp.clear_events()
 259         return events
 260
 261     def event_wait(self, name, timeout=60.0, match=None):
 262         '''
 263         Wait for specified timeout on named event in QMP; optionally filter
 264         results by match.
 265
 266         The 'match' is checked to be a recursive subset of the 'event'; skips
 267         branch processing on match's value None
 268            {"foo": {"bar": 1}} matches {"foo": None}
 269            {"foo": {"bar": 1}} does not matches {"foo": {"baz": None}}
 270         '''
 271         def event_match(event, match=None):
 272             if match is None:
 273                 return True
 274
 275             for key in match:
 276                 if key in event:
 277                     if isinstance(event[key], dict):
 278                         if not event_match(event[key], match[key]):
 279                             return False
 280                     elif event[key] != match[key]:
 281                         return False
 282                 else:
 283                     return False
 284
 285             return True
 286
 287         # Search cached events
 288         for event in self._events:
 289             if (event['event'] == name) and event_match(event, match):
 290                 self._events.remove(event)
 291                 return event
 292
 293         # Poll for new events
 294         while True:
 295             event = self._qmp.pull_event(wait=timeout)
 296             if (event['event'] == name) and event_match(event, match):
 297                 return event
 298             self._events.append(event)
 299
 300         return None
 301
 302     def get_log(self):
 303         '''
 304         After self.shutdown or failed qemu execution, this returns the output
 305         of the qemu process.
 306         '''
 307         return self._iolog