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
  37 class QMPCompleter(list):
  38     def complete(self, text, state):
  39         for cmd in self:
  40             if cmd.startswith(text):
  41                 if not state:
  42                     return cmd
  43                 else:
  44                     state -= 1
  45
  46 class QMPShellError(Exception):
  47     pass
  48
  49 class QMPShellBadPort(QMPShellError):
  50     pass
  51
  52 # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
  53 #       _execute_cmd()). Let's design a better one.
  54 class QMPShell(qmp.QEMUMonitorProtocol):
  55     def __init__(self, address):
  56         qmp.QEMUMonitorProtocol.__init__(self, self.__get_address(address))
  57         self._greeting = None
  58         self._completer = None
  59
  60     def __get_address(self, arg):
  61         """
  62         Figure out if the argument is in the port:host form, if it's not it's
  63         probably a file path.
  64         """
  65         addr = arg.split(':')
  66         if len(addr) == 2:
  67             try:
  68                 port = int(addr[1])
  69             except ValueError:
  70                 raise QMPShellBadPort
  71             return ( addr[0], port )
  72         # socket path
  73         return arg
  74
  75     def _fill_completion(self):
  76         for cmd in self.cmd('query-commands')['return']:
  77             self._completer.append(cmd['name'])
  78
  79     def __completer_setup(self):
  80         self._completer = QMPCompleter()
  81         self._fill_completion()
  82         readline.set_completer(self._completer.complete)
  83         readline.parse_and_bind("tab: complete")
  84         # XXX: default delimiters conflict with some command names (eg. query-),
  85         # clearing everything as it doesn't seem to matter
  86         readline.set_completer_delims('')
  87
  88     def __build_cmd(self, cmdline):
  89         """
  90         Build a QMP input object from a user provided command-line in the
  91         following format:
  92
  93             < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
  94         """
  95         cmdargs = cmdline.split()
  96         qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
  97         for arg in cmdargs[1:]:
  98             opt = arg.split('=')
  99             try:
 100                 value = int(opt[1])
 101             except ValueError:
 102                 value = opt[1]
 103             qmpcmd['arguments'][opt[0]] = value
 104         return qmpcmd
 105
 106     def _execute_cmd(self, cmdline):
 107         try:
 108             qmpcmd = self.__build_cmd(cmdline)
 109         except:
 110             print 'command format: <command-name> ',
 111             print '[arg-name1=arg1] ... [arg-nameN=argN]'
 112             return True
 113         resp = self.cmd_obj(qmpcmd)
 114         if resp is None:
 115             print 'Disconnected'
 116             return False
 117         print resp
 118         return True
 119
 120     def connect(self):
 121         self._greeting = qmp.QEMUMonitorProtocol.connect(self)
 122         self.__completer_setup()
 123
 124     def show_banner(self, msg='Welcome to the QMP low-level shell!'):
 125         print msg
 126         version = self._greeting['QMP']['version']['qemu']
 127         print 'Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro'])
 128
 129     def read_exec_command(self, prompt):
 130         """
 131         Read and execute a command.
 132
 133         @return True if execution was ok, return False if disconnected.
 134         """
 135         try:
 136             cmdline = raw_input(prompt)
 137         except EOFError:
 138             print
 139             return False
 140         if cmdline == '':
 141             for ev in self.get_events():
 142                 print ev
 143             self.clear_events()
 144             return True
 145         else:
 146             return self._execute_cmd(cmdline)
 147
 148 def die(msg):
 149     sys.stderr.write('ERROR: %s\n' % msg)
 150     sys.exit(1)
 151
 152 def fail_cmdline(option=None):
 153     if option:
 154         sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
 155     sys.stderr.write('qemu-shell [ -H ] < UNIX socket path> | < TCP address:port >\n')
 156     sys.exit(1)
 157
 158 def main():
 159     try:
 160         if len(sys.argv) == 2:
 161             qemu = QMPShell(sys.argv[1])
 162         else:
 163                 fail_cmdline()
 164     except QMPShellBadPort:
 165         die('bad port number in command-line')
 166
 167     try:
 168         qemu.connect()
 169     except qmp.QMPConnectError:
 170         die('Didn\'t get QMP greeting message')
 171     except qmp.QMPCapabilitiesError:
 172         die('Could not negotiate capabilities')
 173     except qemu.error:
 174         die('Could not connect to %s' % sys.argv[1])
 175
 176     qemu.show_banner()
 177     while qemu.read_exec_command('(QEMU) '):
 178         pass
 179     qemu.close()
 180
 181 if __name__ == '__main__':
 182     main()