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 subprocess
  19 import qmp.qmp
  20 import shutil
  21 import tempfile
  22
  23
  24 LOG = logging.getLogger(__name__)
  25
  26
  27 class QEMUMachineError(Exception):
  28     """
  29     Exception called when an error in QEMUMachine happens.
  30     """
  31
  32
  33 class MonitorResponseError(qmp.qmp.QMPError):
  34     '''
  35     Represents erroneous QMP monitor reply
  36     '''
  37     def __init__(self, reply):
  38         try:
  39             desc = reply["error"]["desc"]
  40         except KeyError:
  41             desc = reply
  42         super(MonitorResponseError, self).__init__(desc)
  43         self.reply = reply
  44
  45
  46 class QEMUMachine(object):
  47     '''A QEMU VM
  48
  49     Use this object as a context manager to ensure the QEMU process terminates::
  50
  51         with VM(binary) as vm:
  52             ...
  53         # vm is guaranteed to be shut down here
  54     '''
  55
  56     def __init__(self, binary, args=None, wrapper=None, name=None,
  57                  test_dir="/var/tmp", monitor_address=None,
  58                  socket_scm_helper=None):
  59         '''
  60         Initialize a QEMUMachine
  61
  62         @param binary: path to the qemu binary
  63         @param args: list of extra arguments
  64         @param wrapper: list of arguments used as prefix to qemu binary
  65         @param name: prefix for socket and log file names (default: qemu-PID)
  66         @param test_dir: where to create socket and log file
  67         @param monitor_address: address for QMP monitor
  68         @param socket_scm_helper: helper program, required for send_fd_scm()"
  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         self._name = name
  78         self._monitor_address = monitor_address
  79         self._vm_monitor = None
  80         self._qemu_log_path = None
  81         self._qemu_log_file = None
  82         self._popen = None
  83         self._binary = binary
  84         self._args = list(args)     # Force copy args in case we modify them
  85         self._wrapper = wrapper
  86         self._events = []
  87         self._iolog = None
  88         self._socket_scm_helper = socket_scm_helper
  89         self._qmp = None
  90         self._qemu_full_args = None
  91         self._test_dir = test_dir
  92         self._temp_dir = None
  93         self._launched = False
  94
  95         # just in case logging wasn't configured by the main script:
  96         logging.basicConfig()
  97
  98     def __enter__(self):
  99         return self
 100
 101     def __exit__(self, exc_type, exc_val, exc_tb):
 102         self.shutdown()
 103         return False
 104
 105     # This can be used to add an unused monitor instance.
 106     def add_monitor_telnet(self, ip, port):
 107         args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)
 108         self._args.append('-monitor')
 109         self._args.append(args)
 110
 111     def add_fd(self, fd, fdset, opaque, opts=''):
 112         '''Pass a file descriptor to the VM'''
 113         options = ['fd=%d' % fd,
 114                    'set=%d' % fdset,
 115                    'opaque=%s' % opaque]
 116         if opts:
 117             options.append(opts)
 118
 119         self._args.append('-add-fd')
 120         self._args.append(','.join(options))
 121         return self
 122
 123     def send_fd_scm(self, fd_file_path):
 124         # In iotest.py, the qmp should always use unix socket.
 125         assert self._qmp.is_scm_available()
 126         if self._socket_scm_helper is None:
 127             raise QEMUMachineError("No path to socket_scm_helper set")
 128         if not os.path.exists(self._socket_scm_helper):
 129             raise QEMUMachineError("%s does not exist" %
 130                                    self._socket_scm_helper)
 131         fd_param = ["%s" % self._socket_scm_helper,
 132                     "%d" % self._qmp.get_sock_fd(),
 133                     "%s" % fd_file_path]
 134         devnull = open(os.path.devnull, 'rb')
 135         proc = subprocess.Popen(fd_param, stdin=devnull, stdout=subprocess.PIPE,
 136                                 stderr=subprocess.STDOUT)
 137         output = proc.communicate()[0]
 138         if output:
 139             LOG.debug(output)
 140
 141         return proc.returncode
 142
 143     @staticmethod
 144     def _remove_if_exists(path):
 145         '''Remove file object at path if it exists'''
 146         try:
 147             os.remove(path)
 148         except OSError as exception:
 149             if exception.errno == errno.ENOENT:
 150                 return
 151             raise
 152
 153     def is_running(self):
 154         return self._popen is not None and self._popen.poll() is None
 155
 156     def exitcode(self):
 157         if self._popen is None:
 158             return None
 159         return self._popen.poll()
 160
 161     def get_pid(self):
 162         if not self.is_running():
 163             return None
 164         return self._popen.pid
 165
 166     def _load_io_log(self):
 167         if self._qemu_log_path is not None:
 168             with open(self._qemu_log_path, "r") as iolog:
 169                 self._iolog = iolog.read()
 170
 171     def _base_args(self):
 172         if isinstance(self._monitor_address, tuple):
 173             moncdev = "socket,id=mon,host=%s,port=%s" % (
 174                 self._monitor_address[0],
 175                 self._monitor_address[1])
 176         else:
 177             moncdev = 'socket,id=mon,path=%s' % self._vm_monitor
 178         return ['-chardev', moncdev,
 179                 '-mon', 'chardev=mon,mode=control',
 180                 '-display', 'none', '-vga', 'none']
 181
 182     def _pre_launch(self):
 183         self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
 184         if self._monitor_address is not None:
 185             self._vm_monitor = self._monitor_address
 186         else:
 187             self._vm_monitor = os.path.join(self._temp_dir,
 188                                             self._name + "-monitor.sock")
 189         self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
 190         self._qemu_log_file = open(self._qemu_log_path, 'wb')
 191
 192         self._qmp = qmp.qmp.QEMUMonitorProtocol(self._vm_monitor,
 193                                                 server=True)
 194
 195     def _post_launch(self):
 196         self._qmp.accept()
 197
 198     def _post_shutdown(self):
 199         if self._qemu_log_file is not None:
 200             self._qemu_log_file.close()
 201             self._qemu_log_file = None
 202
 203         self._qemu_log_path = None
 204
 205         if self._temp_dir is not None:
 206             shutil.rmtree(self._temp_dir)
 207             self._temp_dir = None
 208
 209     def launch(self):
 210         """
 211         Launch the VM and make sure we cleanup and expose the
 212         command line/output in case of exception
 213         """
 214
 215         if self._launched:
 216             raise QEMUMachineError('VM already launched')
 217
 218         self._iolog = None
 219         self._qemu_full_args = None
 220         try:
 221             self._launch()
 222             self._launched = True
 223         except:
 224             self.shutdown()
 225
 226             LOG.debug('Error launching VM')
 227             if self._qemu_full_args:
 228                 LOG.debug('Command: %r', ' '.join(self._qemu_full_args))
 229             if self._iolog:
 230                 LOG.debug('Output: %r', self._iolog)
 231             raise
 232
 233     def _launch(self):
 234         '''Launch the VM and establish a QMP connection'''
 235         devnull = open(os.path.devnull, 'rb')
 236         self._pre_launch()
 237         self._qemu_full_args = (self._wrapper + [self._binary] +
 238                                 self._base_args() + self._args)
 239         self._popen = subprocess.Popen(self._qemu_full_args,
 240                                        stdin=devnull,
 241                                        stdout=self._qemu_log_file,
 242                                        stderr=subprocess.STDOUT,
 243                                        shell=False)
 244         self._post_launch()
 245
 246     def wait(self):
 247         '''Wait for the VM to power off'''
 248         self._popen.wait()
 249         self._qmp.close()
 250         self._load_io_log()
 251         self._post_shutdown()
 252
 253     def shutdown(self):
 254         '''Terminate the VM and clean up'''
 255         if self.is_running():
 256             try:
 257                 self._qmp.cmd('quit')
 258                 self._qmp.close()
 259             except:
 260                 self._popen.kill()
 261             self._popen.wait()
 262
 263         self._load_io_log()
 264         self._post_shutdown()
 265
 266         exitcode = self.exitcode()
 267         if exitcode is not None and exitcode < 0:
 268             msg = 'qemu received signal %i: %s'
 269             if self._qemu_full_args:
 270                 command = ' '.join(self._qemu_full_args)
 271             else:
 272                 command = ''
 273             LOG.warn(msg, exitcode, command)
 274
 275         self._launched = False
 276
 277     def qmp(self, cmd, conv_keys=True, **args):
 278         '''Invoke a QMP command and return the response dict'''
 279         qmp_args = dict()
 280         for key, value in args.items():
 281             if conv_keys:
 282                 qmp_args[key.replace('_', '-')] = value
 283             else:
 284                 qmp_args[key] = value
 285
 286         return self._qmp.cmd(cmd, args=qmp_args)
 287
 288     def command(self, cmd, conv_keys=True, **args):
 289         '''
 290         Invoke a QMP command.
 291         On success return the response dict.
 292         On failure raise an exception.
 293         '''
 294         reply = self.qmp(cmd, conv_keys, **args)
 295         if reply is None:
 296             raise qmp.qmp.QMPError("Monitor is closed")
 297         if "error" in reply:
 298             raise MonitorResponseError(reply)
 299         return reply["return"]
 300
 301     def get_qmp_event(self, wait=False):
 302         '''Poll for one queued QMP events and return it'''
 303         if len(self._events) > 0:
 304             return self._events.pop(0)
 305         return self._qmp.pull_event(wait=wait)
 306
 307     def get_qmp_events(self, wait=False):
 308         '''Poll for queued QMP events and return a list of dicts'''
 309         events = self._qmp.get_events(wait=wait)
 310         events.extend(self._events)
 311         del self._events[:]
 312         self._qmp.clear_events()
 313         return events
 314
 315     def event_wait(self, name, timeout=60.0, match=None):
 316         '''
 317         Wait for specified timeout on named event in QMP; optionally filter
 318         results by match.
 319
 320         The 'match' is checked to be a recursive subset of the 'event'; skips
 321         branch processing on match's value None
 322            {"foo": {"bar": 1}} matches {"foo": None}
 323            {"foo": {"bar": 1}} does not matches {"foo": {"baz": None}}
 324         '''
 325         def event_match(event, match=None):
 326             if match is None:
 327                 return True
 328
 329             for key in match:
 330                 if key in event:
 331                     if isinstance(event[key], dict):
 332                         if not event_match(event[key], match[key]):
 333                             return False
 334                     elif event[key] != match[key]:
 335                         return False
 336                 else:
 337                     return False
 338
 339             return True
 340
 341         # Search cached events
 342         for event in self._events:
 343             if (event['event'] == name) and event_match(event, match):
 344                 self._events.remove(event)
 345                 return event
 346
 347         # Poll for new events
 348         while True:
 349             event = self._qmp.pull_event(wait=timeout)
 350             if (event['event'] == name) and event_match(event, match):
 351                 return event
 352             self._events.append(event)
 353
 354         return None
 355
 356     def get_log(self):
 357         '''
 358         After self.shutdown or failed qemu execution, this returns the output
 359         of the qemu process.
 360         '''
 361         return self._iolog