xref: /qemu/scripts/qmp/qmp-shell (revision 6faf2384ec78d5a1e0b5dfe430e80cf2278e45c4) 
1#!/usr/bin/env python3
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.
67import argparse
68import ast
69import atexit
70import json
71import os
72import re
73import readline
74import sys
75
76
77sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
78from qemu import qmp
79
80
81class QMPCompleter(list):
82    def complete(self, text, state):
83        for cmd in self:
84            if cmd.startswith(text):
85                if state == 0:
86                    return cmd
87                state -= 1
88        return None
89
90
91class QMPShellError(Exception):
92    pass
93
94
95class FuzzyJSON(ast.NodeTransformer):
96    """
97    This extension of ast.NodeTransformer filters literal "true/false/null"
98    values in a Python AST and replaces them by proper "True/False/None" values
99    that Python can properly evaluate.
100    """
101
102    @classmethod
103    def visit_Name(cls,  # pylint: disable=invalid-name
104                   node: ast.Name) -> ast.AST:
105        if node.id == 'true':
106            return ast.Constant(value=True)
107        if node.id == 'false':
108            return ast.Constant(value=False)
109        if node.id == 'null':
110            return ast.Constant(value=None)
111        return node
112
113
114# TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
115#       _execute_cmd()). Let's design a better one.
116class QMPShell(qmp.QEMUMonitorProtocol):
117    def __init__(self, address, pretty=False, verbose=False):
118        super().__init__(self.parse_address(address))
119        self._greeting = None
120        self._completer = None
121        self._pretty = pretty
122        self._transmode = False
123        self._actions = list()
124        self._histfile = os.path.join(os.path.expanduser('~'),
125                                      '.qmp-shell_history')
126        self.verbose = verbose
127
128    def _fill_completion(self):
129        cmds = self.cmd('query-commands')
130        if 'error' in cmds:
131            return
132        for cmd in cmds['return']:
133            self._completer.append(cmd['name'])
134
135    def __completer_setup(self):
136        self._completer = QMPCompleter()
137        self._fill_completion()
138        readline.set_history_length(1024)
139        readline.set_completer(self._completer.complete)
140        readline.parse_and_bind("tab: complete")
141        # NB: default delimiters conflict with some command names
142        # (eg. query-), clearing everything as it doesn't seem to matter
143        readline.set_completer_delims('')
144        try:
145            readline.read_history_file(self._histfile)
146        except FileNotFoundError:
147            pass
148        except IOError as err:
149            print(f"Failed to read history '{self._histfile}': {err!s}")
150        atexit.register(self.__save_history)
151
152    def __save_history(self):
153        try:
154            readline.write_history_file(self._histfile)
155        except IOError as err:
156            print(f"Failed to save history file '{self._histfile}': {err!s}")
157
158    @classmethod
159    def __parse_value(cls, val):
160        try:
161            return int(val)
162        except ValueError:
163            pass
164
165        if val.lower() == 'true':
166            return True
167        if val.lower() == 'false':
168            return False
169        if val.startswith(('{', '[')):
170            # Try first as pure JSON:
171            try:
172                return json.loads(val)
173            except ValueError:
174                pass
175            # Try once again as FuzzyJSON:
176            try:
177                tree = ast.parse(val, mode='eval')
178                transformed = FuzzyJSON().visit(tree)
179                return ast.literal_eval(transformed)
180            except (SyntaxError, ValueError):
181                pass
182        return val
183
184    def __cli_expr(self, tokens, parent):
185        for arg in tokens:
186            (key, sep, val) = arg.partition('=')
187            if sep != '=':
188                raise QMPShellError(
189                    f"Expected a key=value pair, got '{arg!s}'"
190                )
191
192            value = self.__parse_value(val)
193            optpath = key.split('.')
194            curpath = []
195            for path in optpath[:-1]:
196                curpath.append(path)
197                obj = parent.get(path, {})
198                if not isinstance(obj, dict):
199                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
200                    raise QMPShellError(msg.format('.'.join(curpath)))
201                parent[path] = obj
202                parent = obj
203            if optpath[-1] in parent:
204                if isinstance(parent[optpath[-1]], dict):
205                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
206                    raise QMPShellError(msg.format('.'.join(curpath)))
207                raise QMPShellError(f'Cannot set "{key}" multiple times')
208            parent[optpath[-1]] = value
209
210    def __build_cmd(self, cmdline):
211        """
212        Build a QMP input object from a user provided command-line in the
213        following format:
214
215            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
216        """
217        argument_regex = r'''(?:[^\s"']|"(?:\\.|[^"])*"|'(?:\\.|[^'])*')+'''
218        cmdargs = re.findall(argument_regex, cmdline)
219
220        # Transactional CLI entry/exit:
221        if cmdargs[0] == 'transaction(':
222            self._transmode = True
223            cmdargs.pop(0)
224        elif cmdargs[0] == ')' and self._transmode:
225            self._transmode = False
226            if len(cmdargs) > 1:
227                msg = 'Unexpected input after close of Transaction sub-shell'
228                raise QMPShellError(msg)
229            qmpcmd = {
230                'execute': 'transaction',
231                'arguments': {'actions': self._actions}
232            }
233            self._actions = list()
234            return qmpcmd
235
236        # Nothing to process?
237        if not cmdargs:
238            return None
239
240        # Parse and then cache this Transactional Action
241        if self._transmode:
242            finalize = False
243            action = {'type': cmdargs[0], 'data': {}}
244            if cmdargs[-1] == ')':
245                cmdargs.pop(-1)
246                finalize = True
247            self.__cli_expr(cmdargs[1:], action['data'])
248            self._actions.append(action)
249            return self.__build_cmd(')') if finalize else None
250
251        # Standard command: parse and return it to be executed.
252        qmpcmd = {'execute': cmdargs[0], 'arguments': {}}
253        self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
254        return qmpcmd
255
256    def _print(self, qmp_message):
257        indent = None
258        if self._pretty:
259            indent = 4
260        jsobj = json.dumps(qmp_message, indent=indent, sort_keys=self._pretty)
261        print(str(jsobj))
262
263    def _execute_cmd(self, cmdline):
264        try:
265            qmpcmd = self.__build_cmd(cmdline)
266        except Exception as err:
267            print('Error while parsing command line: %s' % err)
268            print('command format: <command-name> ', end=' ')
269            print('[arg-name1=arg1] ... [arg-nameN=argN]')
270            return True
271        # For transaction mode, we may have just cached the action:
272        if qmpcmd is None:
273            return True
274        if self.verbose:
275            self._print(qmpcmd)
276        resp = self.cmd_obj(qmpcmd)
277        if resp is None:
278            print('Disconnected')
279            return False
280        self._print(resp)
281        return True
282
283    def connect(self, negotiate: bool = True):
284        self._greeting = super().connect(negotiate)
285        self.__completer_setup()
286
287    def show_banner(self, msg='Welcome to the QMP low-level shell!'):
288        print(msg)
289        if not self._greeting:
290            print('Connected')
291            return
292        version = self._greeting['QMP']['version']['qemu']
293        print("Connected to QEMU {major}.{minor}.{micro}\n".format(**version))
294
295    @property
296    def prompt(self):
297        if self._transmode:
298            return 'TRANS> '
299        return '(QEMU) '
300
301    def read_exec_command(self):
302        """
303        Read and execute a command.
304
305        @return True if execution was ok, return False if disconnected.
306        """
307        try:
308            cmdline = input(self.prompt)
309        except EOFError:
310            print()
311            return False
312
313        if cmdline == '':
314            for event in self.get_events():
315                print(event)
316            self.clear_events()
317            return True
318
319        return self._execute_cmd(cmdline)
320
321    def repl(self):
322        self.show_banner()
323        while self.read_exec_command():
324            yield
325        self.close()
326
327
328class HMPShell(QMPShell):
329    def __init__(self, address, pretty=False, verbose=False):
330        super().__init__(address, pretty, verbose)
331        self.__cpu_index = 0
332
333    def __cmd_completion(self):
334        for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
335            if cmd and cmd[0] != '[' and cmd[0] != '\t':
336                name = cmd.split()[0]  # drop help text
337                if name == 'info':
338                    continue
339                if name.find('|') != -1:
340                    # Command in the form 'foobar|f' or 'f|foobar', take the
341                    # full name
342                    opt = name.split('|')
343                    if len(opt[0]) == 1:
344                        name = opt[1]
345                    else:
346                        name = opt[0]
347                self._completer.append(name)
348                self._completer.append('help ' + name)  # help completion
349
350    def __info_completion(self):
351        for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
352            if cmd:
353                self._completer.append('info ' + cmd.split()[1])
354
355    def __other_completion(self):
356        # special cases
357        self._completer.append('help info')
358
359    def _fill_completion(self):
360        self.__cmd_completion()
361        self.__info_completion()
362        self.__other_completion()
363
364    def __cmd_passthrough(self, cmdline, cpu_index=0):
365        return self.cmd_obj({
366            'execute': 'human-monitor-command',
367            'arguments': {
368                'command-line': cmdline,
369                'cpu-index': cpu_index
370            }
371        })
372
373    def _execute_cmd(self, cmdline):
374        if cmdline.split()[0] == "cpu":
375            # trap the cpu command, it requires special setting
376            try:
377                idx = int(cmdline.split()[1])
378                if 'return' not in self.__cmd_passthrough('info version', idx):
379                    print('bad CPU index')
380                    return True
381                self.__cpu_index = idx
382            except ValueError:
383                print('cpu command takes an integer argument')
384                return True
385        resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
386        if resp is None:
387            print('Disconnected')
388            return False
389        assert 'return' in resp or 'error' in resp
390        if 'return' in resp:
391            # Success
392            if len(resp['return']) > 0:
393                print(resp['return'], end=' ')
394        else:
395            # Error
396            print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
397        return True
398
399    def show_banner(self, msg='Welcome to the HMP shell!'):
400        QMPShell.show_banner(self, msg)
401
402
403def die(msg):
404    sys.stderr.write('ERROR: %s\n' % msg)
405    sys.exit(1)
406
407
408def main():
409    parser = argparse.ArgumentParser()
410    parser.add_argument('-H', '--hmp', action='store_true',
411                        help='Use HMP interface')
412    parser.add_argument('-N', '--skip-negotiation', action='store_true',
413                        help='Skip negotiate (for qemu-ga)')
414    parser.add_argument('-v', '--verbose', action='store_true',
415                        help='Verbose (echo commands sent and received)')
416    parser.add_argument('-p', '--pretty', action='store_true',
417                        help='Pretty-print JSON')
418
419    default_server = os.environ.get('QMP_SOCKET')
420    parser.add_argument('qmp_server', action='store',
421                        default=default_server,
422                        help='< UNIX socket path | TCP address:port >')
423
424    args = parser.parse_args()
425    if args.qmp_server is None:
426        parser.error("QMP socket or TCP address must be specified")
427
428    shell_class = HMPShell if args.hmp else QMPShell
429    try:
430        qemu = shell_class(args.qmp_server, args.pretty, args.verbose)
431    except qmp.QMPBadPortError:
432        parser.error(f"Bad port number: {args.qmp_server}")
433        return  # pycharm doesn't know error() is noreturn
434
435    try:
436        qemu.connect(negotiate=not args.skip_negotiation)
437    except qmp.QMPConnectError:
438        die("Didn't get QMP greeting message")
439    except qmp.QMPCapabilitiesError:
440        die("Couldn't negotiate capabilities")
441    except OSError as err:
442        die(f"Couldn't connect to {args.qmp_server}: {err!s}")
443
444    for _ in qemu.repl():
445        pass
446
447
448if __name__ == '__main__':
449    main()
450