scripts/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 # key=value pairs also support Python or JSON object literal subset notations,
  34 # without spaces. Dictionaries/objects {} are supported as are arrays [].
  35 #
  36 #    example-command arg-name1={'key':'value','obj'={'prop':"value"}}
  37 #
  38 # Both JSON and Python formatting should work, including both styles of
  39 # string literal quotes. Both paradigms of literal values should work,
  40 # including null/true/false for JSON and None/True/False for Python.
  41 #
  42 #
  43 # Transactions have the following multi-line format:
  44 #
  45 #    transaction(
  46 #    action-name1 [ arg-name1=arg1 ] ... [arg-nameN=argN ]
  47 #    ...
  48 #    action-nameN [ arg-name1=arg1 ] ... [arg-nameN=argN ]
  49 #    )
  50 #
  51 # One line transactions are also supported:
  52 #
  53 #    transaction( action-name1 ... )
  54 #
  55 # For example:
  56 #
  57 #     (QEMU) transaction(
  58 #     TRANS> block-dirty-bitmap-add node=drive0 name=bitmap1
  59 #     TRANS> block-dirty-bitmap-clear node=drive0 name=bitmap0
  60 #     TRANS> )
  61 #     {"return": {}}
  62 #     (QEMU)
  63 #
  64 # Use the -v and -p options to activate the verbose and pretty-print options,
  65 # which will echo back the properly formatted JSON-compliant QMP that is being
  66 # sent to QEMU, which is useful for debugging and documentation generation.
  67
  68 from __future__ import print_function
  69 import json
  70 import ast
  71 import readline
  72 import sys
  73 import os
  74 import errno
  75 import atexit
  76 import re
  77
  78 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
  79 from qemu import qmp
  80
  81 if sys.version_info[0] == 2:
  82     input = raw_input
  83
  84 class QMPCompleter(list):
  85     def complete(self, text, state):
  86         for cmd in self:
  87             if cmd.startswith(text):
  88                 if not state:
  89                     return cmd
  90                 else:
  91                     state -= 1
  92
  93 class QMPShellError(Exception):
  94     pass
  95
  96 class QMPShellBadPort(QMPShellError):
  97     pass
  98
  99 class FuzzyJSON(ast.NodeTransformer):
 100     '''This extension of ast.NodeTransformer filters literal "true/false/null"
 101     values in an AST and replaces them by proper "True/False/None" values that
 102     Python can properly evaluate.'''
 103     def visit_Name(self, node):
 104         if node.id == 'true':
 105             node.id = 'True'
 106         if node.id == 'false':
 107             node.id = 'False'
 108         if node.id == 'null':
 109             node.id = 'None'
 110         return node
 111
 112 # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
 113 #       _execute_cmd()). Let's design a better one.
 114 class QMPShell(qmp.QEMUMonitorProtocol):
 115     def __init__(self, address, pretty=False):
 116         super(QMPShell, self).__init__(self.__get_address(address))
 117         self._greeting = None
 118         self._completer = None
 119         self._pretty = pretty
 120         self._transmode = False
 121         self._actions = list()
 122         self._histfile = os.path.join(os.path.expanduser('~'),
 123                                       '.qmp-shell_history')
 124
 125     def __get_address(self, arg):
 126         """
 127         Figure out if the argument is in the port:host form, if it's not it's
 128         probably a file path.
 129         """
 130         addr = arg.split(':')
 131         if len(addr) == 2:
 132             try:
 133                 port = int(addr[1])
 134             except ValueError:
 135                 raise QMPShellBadPort
 136             return ( addr[0], port )
 137         # socket path
 138         return arg
 139
 140     def _fill_completion(self):
 141         cmds = self.cmd('query-commands')
 142         if 'error' in cmds:
 143             return
 144         for cmd in cmds['return']:
 145             self._completer.append(cmd['name'])
 146
 147     def __completer_setup(self):
 148         self._completer = QMPCompleter()
 149         self._fill_completion()
 150         readline.set_history_length(1024)
 151         readline.set_completer(self._completer.complete)
 152         readline.parse_and_bind("tab: complete")
 153         # XXX: default delimiters conflict with some command names (eg. query-),
 154         # clearing everything as it doesn't seem to matter
 155         readline.set_completer_delims('')
 156         try:
 157             readline.read_history_file(self._histfile)
 158         except Exception as e:
 159             if isinstance(e, IOError) and e.errno == errno.ENOENT:
 160                 # File not found. No problem.
 161                 pass
 162             else:
 163                 print("Failed to read history '%s'; %s" % (self._histfile, e))
 164         atexit.register(self.__save_history)
 165
 166     def __save_history(self):
 167         try:
 168             readline.write_history_file(self._histfile)
 169         except Exception as e:
 170             print("Failed to save history file '%s'; %s" % (self._histfile, e))
 171
 172     def __parse_value(self, val):
 173         try:
 174             return int(val)
 175         except ValueError:
 176             pass
 177
 178         if val.lower() == 'true':
 179             return True
 180         if val.lower() == 'false':
 181             return False
 182         if val.startswith(('{', '[')):
 183             # Try first as pure JSON:
 184             try:
 185                 return json.loads(val)
 186             except ValueError:
 187                 pass
 188             # Try once again as FuzzyJSON:
 189             try:
 190                 st = ast.parse(val, mode='eval')
 191                 return ast.literal_eval(FuzzyJSON().visit(st))
 192             except SyntaxError:
 193                 pass
 194             except ValueError:
 195                 pass
 196         return val
 197
 198     def __cli_expr(self, tokens, parent):
 199         for arg in tokens:
 200             (key, sep, val) = arg.partition('=')
 201             if sep != '=':
 202                 raise QMPShellError("Expected a key=value pair, got '%s'" % arg)
 203
 204             value = self.__parse_value(val)
 205             optpath = key.split('.')
 206             curpath = []
 207             for p in optpath[:-1]:
 208                 curpath.append(p)
 209                 d = parent.get(p, {})
 210                 if type(d) is not dict:
 211                     raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
 212                 parent[p] = d
 213                 parent = d
 214             if optpath[-1] in parent:
 215                 if type(parent[optpath[-1]]) is dict:
 216                     raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
 217                 else:
 218                     raise QMPShellError('Cannot set "%s" multiple times' % key)
 219             parent[optpath[-1]] = value
 220
 221     def __build_cmd(self, cmdline):
 222         """
 223         Build a QMP input object from a user provided command-line in the
 224         following format:
 225
 226             < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
 227         """
 228         cmdargs = re.findall(r'''(?:[^\s"']|"(?:\\.|[^"])*"|'(?:\\.|[^'])*')+''', cmdline)
 229
 230         # Transactional CLI entry/exit:
 231         if cmdargs[0] == 'transaction(':
 232             self._transmode = True
 233             cmdargs.pop(0)
 234         elif cmdargs[0] == ')' and self._transmode:
 235             self._transmode = False
 236             if len(cmdargs) > 1:
 237                 raise QMPShellError("Unexpected input after close of Transaction sub-shell")
 238             qmpcmd = { 'execute': 'transaction',
 239                        'arguments': { 'actions': self._actions } }
 240             self._actions = list()
 241             return qmpcmd
 242
 243         # Nothing to process?
 244         if not cmdargs:
 245             return None
 246
 247         # Parse and then cache this Transactional Action
 248         if self._transmode:
 249             finalize = False
 250             action = { 'type': cmdargs[0], 'data': {} }
 251             if cmdargs[-1] == ')':
 252                 cmdargs.pop(-1)
 253                 finalize = True
 254             self.__cli_expr(cmdargs[1:], action['data'])
 255             self._actions.append(action)
 256             return self.__build_cmd(')') if finalize else None
 257
 258         # Standard command: parse and return it to be executed.
 259         qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
 260         self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
 261         return qmpcmd
 262
 263     def _print(self, qmp):
 264         indent = None
 265         if self._pretty:
 266             indent = 4
 267         jsobj = json.dumps(qmp, indent=indent)
 268         print(str(jsobj))
 269
 270     def _execute_cmd(self, cmdline):
 271         try:
 272             qmpcmd = self.__build_cmd(cmdline)
 273         except Exception as e:
 274             print('Error while parsing command line: %s' % e)
 275             print('command format: <command-name> ', end=' ')
 276             print('[arg-name1=arg1] ... [arg-nameN=argN]')
 277             return True
 278         # For transaction mode, we may have just cached the action:
 279         if qmpcmd is None:
 280             return True
 281         if self._verbose:
 282             self._print(qmpcmd)
 283         resp = self.cmd_obj(qmpcmd)
 284         if resp is None:
 285             print('Disconnected')
 286             return False
 287         self._print(resp)
 288         return True
 289
 290     def connect(self, negotiate):
 291         self._greeting = super(QMPShell, self).connect(negotiate)
 292         self.__completer_setup()
 293
 294     def show_banner(self, msg='Welcome to the QMP low-level shell!'):
 295         print(msg)
 296         if not self._greeting:
 297             print('Connected')
 298             return
 299         version = self._greeting['QMP']['version']['qemu']
 300         print('Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro']))
 301
 302     def get_prompt(self):
 303         if self._transmode:
 304             return "TRANS> "
 305         return "(QEMU) "
 306
 307     def read_exec_command(self, prompt):
 308         """
 309         Read and execute a command.
 310
 311         @return True if execution was ok, return False if disconnected.
 312         """
 313         try:
 314             cmdline = input(prompt)
 315         except EOFError:
 316             print()
 317             return False
 318         if cmdline == '':
 319             for ev in self.get_events():
 320                 print(ev)
 321             self.clear_events()
 322             return True
 323         else:
 324             return self._execute_cmd(cmdline)
 325
 326     def set_verbosity(self, verbose):
 327         self._verbose = verbose
 328
 329 class HMPShell(QMPShell):
 330     def __init__(self, address):
 331         QMPShell.__init__(self, address)
 332         self.__cpu_index = 0
 333
 334     def __cmd_completion(self):
 335         for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
 336             if cmd and cmd[0] != '[' and cmd[0] != '\t':
 337                 name = cmd.split()[0] # drop help text
 338                 if name == 'info':
 339                     continue
 340                 if name.find('|') != -1:
 341                     # Command in the form 'foobar|f' or 'f|foobar', take the
 342                     # full name
 343                     opt = name.split('|')
 344                     if len(opt[0]) == 1:
 345                         name = opt[1]
 346                     else:
 347                         name = opt[0]
 348                 self._completer.append(name)
 349                 self._completer.append('help ' + name) # help completion
 350
 351     def __info_completion(self):
 352         for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
 353             if cmd:
 354                 self._completer.append('info ' + cmd.split()[1])
 355
 356     def __other_completion(self):
 357         # special cases
 358         self._completer.append('help info')
 359
 360     def _fill_completion(self):
 361         self.__cmd_completion()
 362         self.__info_completion()
 363         self.__other_completion()
 364
 365     def __cmd_passthrough(self, cmdline, cpu_index = 0):
 366         return self.cmd_obj({ 'execute': 'human-monitor-command', 'arguments':
 367                               { 'command-line': cmdline,
 368                                 'cpu-index': cpu_index } })
 369
 370     def _execute_cmd(self, cmdline):
 371         if cmdline.split()[0] == "cpu":
 372             # trap the cpu command, it requires special setting
 373             try:
 374                 idx = int(cmdline.split()[1])
 375                 if not 'return' in self.__cmd_passthrough('info version', idx):
 376                     print('bad CPU index')
 377                     return True
 378                 self.__cpu_index = idx
 379             except ValueError:
 380                 print('cpu command takes an integer argument')
 381                 return True
 382         resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
 383         if resp is None:
 384             print('Disconnected')
 385             return False
 386         assert 'return' in resp or 'error' in resp
 387         if 'return' in resp:
 388             # Success
 389             if len(resp['return']) > 0:
 390                 print(resp['return'], end=' ')
 391         else:
 392             # Error
 393             print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
 394         return True
 395
 396     def show_banner(self):
 397         QMPShell.show_banner(self, msg='Welcome to the HMP shell!')
 398
 399 def die(msg):
 400     sys.stderr.write('ERROR: %s\n' % msg)
 401     sys.exit(1)
 402
 403 def fail_cmdline(option=None):
 404     if option:
 405         sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
 406     sys.stderr.write('qmp-shell [ -v ] [ -p ] [ -H ] [ -N ] < UNIX socket path> | < TCP address:port >\n')
 407     sys.stderr.write('    -v     Verbose (echo command sent and received)\n')
 408     sys.stderr.write('    -p     Pretty-print JSON\n')
 409     sys.stderr.write('    -H     Use HMP interface\n')
 410     sys.stderr.write('    -N     Skip negotiate (for qemu-ga)\n')
 411     sys.exit(1)
 412
 413 def main():
 414     addr = ''
 415     qemu = None
 416     hmp = False
 417     pretty = False
 418     verbose = False
 419     negotiate = True
 420
 421     try:
 422         for arg in sys.argv[1:]:
 423             if arg == "-H":
 424                 if qemu is not None:
 425                     fail_cmdline(arg)
 426                 hmp = True
 427             elif arg == "-p":
 428                 pretty = True
 429             elif arg == "-N":
 430                 negotiate = False
 431             elif arg == "-v":
 432                 verbose = True
 433             else:
 434                 if qemu is not None:
 435                     fail_cmdline(arg)
 436                 if hmp:
 437                     qemu = HMPShell(arg)
 438                 else:
 439                     qemu = QMPShell(arg, pretty)
 440                 addr = arg
 441
 442         if qemu is None:
 443             fail_cmdline()
 444     except QMPShellBadPort:
 445         die('bad port number in command-line')
 446
 447     try:
 448         qemu.connect(negotiate)
 449     except qmp.QMPConnectError:
 450         die('Didn\'t get QMP greeting message')
 451     except qmp.QMPCapabilitiesError:
 452         die('Could not negotiate capabilities')
 453     except qemu.error:
 454         die('Could not connect to %s' % addr)
 455
 456     qemu.show_banner()
 457     qemu.set_verbosity(verbose)
 458     while qemu.read_exec_command(qemu.get_prompt()):
 459         pass
 460     qemu.close()
 461
 462 if __name__ == '__main__':
 463     main()