QMP/qmp-shell

   1 #!/usr/bin/python
   2 #
   3 # Low-level QEMU shell on top of QMP.
   4 #
   5 # Copyright (C) 2009, 2010 Red Hat Inc.
   6 #
   7 # Authors:
   8 #  Luiz Capitulino <lcapitulino@redhat.com>
   9 #
  10 # This work is licensed under the terms of the GNU GPL, version 2.  See
  11 # the COPYING file in the top-level directory.
  12 #
  13 # Usage:
  14 #
  15 # Start QEMU with:
  16 #
  17 # # qemu [...] -qmp unix:./qmp-sock,server
  18 #
  19 # Run the shell:
  20 #
  21 # $ qmp-shell ./qmp-sock
  22 #
  23 # Commands have the following format:
  24 #
  25 #    < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
  26 #
  27 # For example:
  28 #
  29 # (QEMU) device_add driver=e1000 id=net1
  30 # {u'return': {}}
  31 # (QEMU)
  32
  33 import qmp
  34 import readline
  35 import sys
  36 import pprint
  37
  38 class QMPCompleter(list):
  39     def complete(self, text, state):
  40         for cmd in self:
  41             if cmd.startswith(text):
  42                 if not state:
  43                     return cmd
  44                 else:
  45                     state -= 1
  46
  47 class QMPShellError(Exception):
  48     pass
  49
  50 class QMPShellBadPort(QMPShellError):
  51     pass
  52
  53 # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
  54 #       _execute_cmd()). Let's design a better one.
  55 class QMPShell(qmp.QEMUMonitorProtocol):
  56     def __init__(self, address, pp=None):
  57         qmp.QEMUMonitorProtocol.__init__(self, self.__get_address(address))
  58         self._greeting = None
  59         self._completer = None
  60         self._pp = pp
  61
  62     def __get_address(self, arg):
  63         """
  64         Figure out if the argument is in the port:host form, if it's not it's
  65         probably a file path.
  66         """
  67         addr = arg.split(':')
  68         if len(addr) == 2:
  69             try:
  70                 port = int(addr[1])
  71             except ValueError:
  72                 raise QMPShellBadPort
  73             return ( addr[0], port )
  74         # socket path
  75         return arg
  76
  77     def _fill_completion(self):
  78         for cmd in self.cmd('query-commands')['return']:
  79             self._completer.append(cmd['name'])
  80
  81     def __completer_setup(self):
  82         self._completer = QMPCompleter()
  83         self._fill_completion()
  84         readline.set_completer(self._completer.complete)
  85         readline.parse_and_bind("tab: complete")
  86         # XXX: default delimiters conflict with some command names (eg. query-),
  87         # clearing everything as it doesn't seem to matter
  88         readline.set_completer_delims('')
  89
  90     def __build_cmd(self, cmdline):
  91         """
  92         Build a QMP input object from a user provided command-line in the
  93         following format:
  94
  95             < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
  96         """
  97         cmdargs = cmdline.split()
  98         qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
  99         for arg in cmdargs[1:]:
 100             opt = arg.split('=')
 101             try:
 102                 value = int(opt[1])
 103             except ValueError:
 104                 if opt[1] == 'true':
 105                     value = True
 106                 elif opt[1] == 'false':
 107                     value = False
 108                 else:
 109                     value = opt[1]
 110             qmpcmd['arguments'][opt[0]] = value
 111         return qmpcmd
 112
 113     def _execute_cmd(self, cmdline):
 114         try:
 115             qmpcmd = self.__build_cmd(cmdline)
 116         except:
 117             print 'command format: <command-name> ',
 118             print '[arg-name1=arg1] ... [arg-nameN=argN]'
 119             return True
 120         resp = self.cmd_obj(qmpcmd)
 121         if resp is None:
 122             print 'Disconnected'
 123             return False
 124
 125         if self._pp is not None:
 126             self._pp.pprint(resp)
 127         else:
 128             print resp
 129         return True
 130
 131     def connect(self):
 132         self._greeting = qmp.QEMUMonitorProtocol.connect(self)
 133         self.__completer_setup()
 134
 135     def show_banner(self, msg='Welcome to the QMP low-level shell!'):
 136         print msg
 137         version = self._greeting['QMP']['version']['qemu']
 138         print 'Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro'])
 139
 140     def read_exec_command(self, prompt):
 141         """
 142         Read and execute a command.
 143
 144         @return True if execution was ok, return False if disconnected.
 145         """
 146         try:
 147             cmdline = raw_input(prompt)
 148         except EOFError:
 149             print
 150             return False
 151         if cmdline == '':
 152             for ev in self.get_events():
 153                 print ev
 154             self.clear_events()
 155             return True
 156         else:
 157             return self._execute_cmd(cmdline)
 158
 159 class HMPShell(QMPShell):
 160     def __init__(self, address):
 161         QMPShell.__init__(self, address)
 162         self.__cpu_index = 0
 163
 164     def __cmd_completion(self):
 165         for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
 166             if cmd and cmd[0] != '[' and cmd[0] != '\t':
 167                 name = cmd.split()[0] # drop help text
 168                 if name == 'info':
 169                     continue
 170                 if name.find('|') != -1:
 171                     # Command in the form 'foobar|f' or 'f|foobar', take the
 172                     # full name
 173                     opt = name.split('|')
 174                     if len(opt[0]) == 1:
 175                         name = opt[1]
 176                     else:
 177                         name = opt[0]
 178                 self._completer.append(name)
 179                 self._completer.append('help ' + name) # help completion
 180
 181     def __info_completion(self):
 182         for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
 183             if cmd:
 184                 self._completer.append('info ' + cmd.split()[1])
 185
 186     def __other_completion(self):
 187         # special cases
 188         self._completer.append('help info')
 189
 190     def _fill_completion(self):
 191         self.__cmd_completion()
 192         self.__info_completion()
 193         self.__other_completion()
 194
 195     def __cmd_passthrough(self, cmdline, cpu_index = 0):
 196         return self.cmd_obj({ 'execute': 'human-monitor-command', 'arguments':
 197                               { 'command-line': cmdline,
 198                                 'cpu-index': cpu_index } })
 199
 200     def _execute_cmd(self, cmdline):
 201         if cmdline.split()[0] == "cpu":
 202             # trap the cpu command, it requires special setting
 203             try:
 204                 idx = int(cmdline.split()[1])
 205                 if not 'return' in self.__cmd_passthrough('info version', idx):
 206                     print 'bad CPU index'
 207                     return True
 208                 self.__cpu_index = idx
 209             except ValueError:
 210                 print 'cpu command takes an integer argument'
 211                 return True
 212         resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
 213         if resp is None:
 214             print 'Disconnected'
 215             return False
 216         assert 'return' in resp or 'error' in resp
 217         if 'return' in resp:
 218             # Success
 219             if len(resp['return']) > 0:
 220                 print resp['return'],
 221         else:
 222             # Error
 223             print '%s: %s' % (resp['error']['class'], resp['error']['desc'])
 224         return True
 225
 226     def show_banner(self):
 227         QMPShell.show_banner(self, msg='Welcome to the HMP shell!')
 228
 229 def die(msg):
 230     sys.stderr.write('ERROR: %s\n' % msg)
 231     sys.exit(1)
 232
 233 def fail_cmdline(option=None):
 234     if option:
 235         sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
 236     sys.stderr.write('qemu-shell [ -p ] [ -H ] < UNIX socket path> | < TCP address:port >\n')
 237     sys.exit(1)
 238
 239 def main():
 240     addr = ''
 241     qemu = None
 242     hmp = False
 243     pp = None
 244
 245     try:
 246         for arg in sys.argv[1:]:
 247             if arg == "-H":
 248                 if qemu is not None:
 249                     fail_cmdline(arg)
 250                 hmp = True
 251             elif arg == "-p":
 252                 if pp is not None:
 253                     fail_cmdline(arg)
 254                 pp = pprint.PrettyPrinter(indent=4)
 255             else:
 256                 if qemu is not None:
 257                     fail_cmdline(arg)
 258                 if hmp:
 259                     qemu = HMPShell(arg)
 260                 else:
 261                     qemu = QMPShell(arg, pp)
 262                 addr = arg
 263
 264         if qemu is None:
 265             fail_cmdline()
 266     except QMPShellBadPort:
 267         die('bad port number in command-line')
 268
 269     try:
 270         qemu.connect()
 271     except qmp.QMPConnectError:
 272         die('Didn\'t get QMP greeting message')
 273     except qmp.QMPCapabilitiesError:
 274         die('Could not negotiate capabilities')
 275     except qemu.error:
 276         die('Could not connect to %s' % addr)
 277
 278     qemu.show_banner()
 279     while qemu.read_exec_command('(QEMU) '):
 280         pass
 281     qemu.close()
 282
 283 if __name__ == '__main__':
 284     main()