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         self._qemu_full_args = None
  91
  92         # just in case logging wasn't configured by the main script:
  93         logging.basicConfig(level=(logging.DEBUG if debug else logging.WARN))
  94
  95     def __enter__(self):
  96         return self
  97
  98     def __exit__(self, exc_type, exc_val, exc_tb):
  99         self.shutdown()
 100         return False
 101
 102     # This can be used to add an unused monitor instance.
 103     def add_monitor_telnet(self, ip, port):
 104         args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)
 105         self._args.append('-monitor')
 106         self._args.append(args)
 107
 108     def add_fd(self, fd, fdset, opaque, opts=''):
 109         '''Pass a file descriptor to the VM'''
 110         options = ['fd=%d' % fd,
 111                    'set=%d' % fdset,
 112                    'opaque=%s' % opaque]
 113         if opts:
 114             options.append(opts)
 115
 116         self._args.append('-add-fd')
 117         self._args.append(','.join(options))
 118         return self
 119
 120     def send_fd_scm(self, fd_file_path):
 121         # In iotest.py, the qmp should always use unix socket.
 122         assert self._qmp.is_scm_available()
 123         if self._socket_scm_helper is None:
 124             raise QEMUMachineError("No path to socket_scm_helper set")
 125         if not os.path.exists(self._socket_scm_helper):
 126             raise QEMUMachineError("%s does not exist" %
 127                                    self._socket_scm_helper)
 128         fd_param = ["%s" % self._socket_scm_helper,
 129                     "%d" % self._qmp.get_sock_fd(),
 130                     "%s" % fd_file_path]
 131         devnull = open(os.path.devnull, 'rb')
 132         proc = subprocess.Popen(fd_param, stdin=devnull, stdout=subprocess.PIPE,
 133                                 stderr=subprocess.STDOUT)
 134         output = proc.communicate()[0]
 135         if output:
 136             LOG.debug(output)
 137
 138         return proc.returncode
 139
 140     @staticmethod
 141     def _remove_if_exists(path):
 142         '''Remove file object at path if it exists'''
 143         try:
 144             os.remove(path)
 145         except OSError as exception:
 146             if exception.errno == errno.ENOENT:
 147                 return
 148             raise
 149
 150     def is_running(self):
 151         return self._popen is not None and self._popen.returncode is None
 152
 153     def exitcode(self):
 154         if self._popen is None:
 155             return None
 156         return self._popen.returncode
 157
 158     def get_pid(self):
 159         if not self.is_running():
 160             return None
 161         return self._popen.pid
 162
 163     def _load_io_log(self):
 164         with open(self._qemu_log_path, "r") as iolog:
 165             self._iolog = iolog.read()
 166
 167     def _base_args(self):
 168         if isinstance(self._monitor_address, tuple):
 169             moncdev = "socket,id=mon,host=%s,port=%s" % (
 170                 self._monitor_address[0],
 171                 self._monitor_address[1])
 172         else:
 173             moncdev = 'socket,id=mon,path=%s' % self._monitor_address
 174         return ['-chardev', moncdev,
 175                 '-mon', 'chardev=mon,mode=control',
 176                 '-display', 'none', '-vga', 'none']
 177
 178     def _pre_launch(self):
 179         self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address,
 180                                                 server=True,
 181                                                 debug=self._debug)
 182
 183     def _post_launch(self):
 184         self._qmp.accept()
 185
 186     def _post_shutdown(self):
 187         if not isinstance(self._monitor_address, tuple):
 188             self._remove_if_exists(self._monitor_address)
 189         self._remove_if_exists(self._qemu_log_path)
 190
 191     def launch(self):
 192         '''Launch the VM and establish a QMP connection'''
 193         self._iolog = None
 194         self._qemu_full_args = None
 195         devnull = open(os.path.devnull, 'rb')
 196         qemulog = open(self._qemu_log_path, 'wb')
 197         try:
 198             self._pre_launch()
 199             self._qemu_full_args = (self._wrapper + [self._binary] +
 200                                     self._base_args() + self._args)
 201             self._popen = subprocess.Popen(self._qemu_full_args,
 202                                            stdin=devnull,
 203                                            stdout=qemulog,
 204                                            stderr=subprocess.STDOUT,
 205                                            shell=False)
 206             self._post_launch()
 207         except:
 208             if self.is_running():
 209                 self._popen.kill()
 210                 self._popen.wait()
 211             self._load_io_log()
 212             self._post_shutdown()
 213
 214             LOG.debug('Error launching VM')
 215             if self._qemu_full_args:
 216                 LOG.debug('Command: %r', ' '.join(self._qemu_full_args))
 217             if self._iolog:
 218                 LOG.debug('Output: %r', self._iolog)
 219             raise
 220
 221     def wait(self):
 222         '''Wait for the VM to power off'''
 223         self._popen.wait()
 224         self._qmp.close()
 225         self._load_io_log()
 226         self._post_shutdown()
 227
 228     def shutdown(self):
 229         '''Terminate the VM and clean up'''
 230         if self.is_running():
 231             try:
 232                 self._qmp.cmd('quit')
 233                 self._qmp.close()
 234             except:
 235                 self._popen.kill()
 236             self._popen.wait()
 237
 238             self._load_io_log()
 239             self._post_shutdown()
 240
 241         exitcode = self.exitcode()
 242         if exitcode is not None and exitcode < 0:
 243             msg = 'qemu received signal %i: %s'
 244             if self._qemu_full_args:
 245                 command = ' '.join(self._qemu_full_args)
 246             else:
 247                 command = ''
 248             LOG.warn(msg, exitcode, command)
 249
 250     def qmp(self, cmd, conv_keys=True, **args):
 251         '''Invoke a QMP command and return the response dict'''
 252         qmp_args = dict()
 253         for key, value in args.iteritems():
 254             if conv_keys:
 255                 qmp_args[key.replace('_', '-')] = value
 256             else:
 257                 qmp_args[key] = value
 258
 259         return self._qmp.cmd(cmd, args=qmp_args)
 260
 261     def command(self, cmd, conv_keys=True, **args):
 262         '''
 263         Invoke a QMP command.
 264         On success return the response dict.
 265         On failure raise an exception.
 266         '''
 267         reply = self.qmp(cmd, conv_keys, **args)
 268         if reply is None:
 269             raise qmp.qmp.QMPError("Monitor is closed")
 270         if "error" in reply:
 271             raise MonitorResponseError(reply)
 272         return reply["return"]
 273
 274     def get_qmp_event(self, wait=False):
 275         '''Poll for one queued QMP events and return it'''
 276         if len(self._events) > 0:
 277             return self._events.pop(0)
 278         return self._qmp.pull_event(wait=wait)
 279
 280     def get_qmp_events(self, wait=False):
 281         '''Poll for queued QMP events and return a list of dicts'''
 282         events = self._qmp.get_events(wait=wait)
 283         events.extend(self._events)
 284         del self._events[:]
 285         self._qmp.clear_events()
 286         return events
 287
 288     def event_wait(self, name, timeout=60.0, match=None):
 289         '''
 290         Wait for specified timeout on named event in QMP; optionally filter
 291         results by match.
 292
 293         The 'match' is checked to be a recursive subset of the 'event'; skips
 294         branch processing on match's value None
 295            {"foo": {"bar": 1}} matches {"foo": None}
 296            {"foo": {"bar": 1}} does not matches {"foo": {"baz": None}}
 297         '''
 298         def event_match(event, match=None):
 299             if match is None:
 300                 return True
 301
 302             for key in match:
 303                 if key in event:
 304                     if isinstance(event[key], dict):
 305                         if not event_match(event[key], match[key]):
 306                             return False
 307                     elif event[key] != match[key]:
 308                         return False
 309                 else:
 310                     return False
 311
 312             return True
 313
 314         # Search cached events
 315         for event in self._events:
 316             if (event['event'] == name) and event_match(event, match):
 317                 self._events.remove(event)
 318                 return event
 319
 320         # Poll for new events
 321         while True:
 322             event = self._qmp.pull_event(wait=timeout)
 323             if (event['event'] == name) and event_match(event, match):
 324                 return event
 325             self._events.append(event)
 326
 327         return None
 328
 329     def get_log(self):
 330         '''
 331         After self.shutdown or failed qemu execution, this returns the output
 332         of the qemu process.
 333         '''
 334         return self._iolog