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