xref: /qemu/scripts/qmp/qmp-shell (revision 82f51817) 
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
68from __future__ import print_function
69import json
70import ast
71import readline
72import sys
73import os
74import errno
75import atexit
76import shlex
77
78sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
79from qemu import qmp
80
81class 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
90class QMPShellError(Exception):
91    pass
92
93class QMPShellBadPort(QMPShellError):
94    pass
95
96class 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.
111class 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 = shlex.split(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
326class 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
396def die(msg):
397    sys.stderr.write('ERROR: %s\n' % msg)
398    sys.exit(1)
399
400def 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
410def 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
459if __name__ == '__main__':
460    main()
461