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