xref: /qemu/scripts/qmp/qmp-shell (revision 74688377feb551101f8a3e3de483df56d30299e4) 
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 json
70import logging
71import os
72import re
73import readline
74import sys
75from typing import (
76    Iterator,
77    List,
78    NoReturn,
79    Optional,
80    Sequence,
81)
82
83
84sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
85from qemu import qmp
86from qemu.qmp import QMPMessage
87
88
89LOG = logging.getLogger(__name__)
90
91
92class QMPCompleter:
93    # NB: Python 3.9+ will probably allow us to subclass list[str] directly,
94    # but pylint as of today does not know that List[str] is simply 'list'.
95    def __init__(self) -> None:
96        self._matches: List[str] = []
97
98    def append(self, value: str) -> None:
99        return self._matches.append(value)
100
101    def complete(self, text: str, state: int) -> Optional[str]:
102        for cmd in self._matches:
103            if cmd.startswith(text):
104                if state == 0:
105                    return cmd
106                state -= 1
107        return None
108
109
110class QMPShellError(Exception):
111    pass
112
113
114class FuzzyJSON(ast.NodeTransformer):
115    """
116    This extension of ast.NodeTransformer filters literal "true/false/null"
117    values in a Python AST and replaces them by proper "True/False/None" values
118    that Python can properly evaluate.
119    """
120
121    @classmethod
122    def visit_Name(cls,  # pylint: disable=invalid-name
123                   node: ast.Name) -> ast.AST:
124        if node.id == 'true':
125            return ast.Constant(value=True)
126        if node.id == 'false':
127            return ast.Constant(value=False)
128        if node.id == 'null':
129            return ast.Constant(value=None)
130        return node
131
132
133class QMPShell(qmp.QEMUMonitorProtocol):
134    def __init__(self, address: qmp.SocketAddrT,
135                 pretty: bool = False, verbose: bool = False):
136        super().__init__(address)
137        self._greeting: Optional[QMPMessage] = None
138        self._completer = QMPCompleter()
139        self._transmode = False
140        self._actions: List[QMPMessage] = []
141        self._histfile = os.path.join(os.path.expanduser('~'),
142                                      '.qmp-shell_history')
143        self.pretty = pretty
144        self.verbose = verbose
145
146    def close(self) -> None:
147        # Hook into context manager of parent to save shell history.
148        self._save_history()
149        super().close()
150
151    def _fill_completion(self) -> None:
152        cmds = self.cmd('query-commands')
153        if 'error' in cmds:
154            return
155        for cmd in cmds['return']:
156            self._completer.append(cmd['name'])
157
158    def __completer_setup(self) -> None:
159        self._completer = QMPCompleter()
160        self._fill_completion()
161        readline.set_history_length(1024)
162        readline.set_completer(self._completer.complete)
163        readline.parse_and_bind("tab: complete")
164        # NB: default delimiters conflict with some command names
165        # (eg. query-), clearing everything as it doesn't seem to matter
166        readline.set_completer_delims('')
167        try:
168            readline.read_history_file(self._histfile)
169        except FileNotFoundError:
170            pass
171        except IOError as err:
172            msg = f"Failed to read history '{self._histfile}': {err!s}"
173            LOG.warning(msg)
174
175    def _save_history(self) -> None:
176        try:
177            readline.write_history_file(self._histfile)
178        except IOError as err:
179            msg = f"Failed to save history file '{self._histfile}': {err!s}"
180            LOG.warning(msg)
181
182    @classmethod
183    def __parse_value(cls, val: str) -> object:
184        try:
185            return int(val)
186        except ValueError:
187            pass
188
189        if val.lower() == 'true':
190            return True
191        if val.lower() == 'false':
192            return False
193        if val.startswith(('{', '[')):
194            # Try first as pure JSON:
195            try:
196                return json.loads(val)
197            except ValueError:
198                pass
199            # Try once again as FuzzyJSON:
200            try:
201                tree = ast.parse(val, mode='eval')
202                transformed = FuzzyJSON().visit(tree)
203                return ast.literal_eval(transformed)
204            except (SyntaxError, ValueError):
205                pass
206        return val
207
208    def __cli_expr(self,
209                   tokens: Sequence[str],
210                   parent: qmp.QMPObject) -> None:
211        for arg in tokens:
212            (key, sep, val) = arg.partition('=')
213            if sep != '=':
214                raise QMPShellError(
215                    f"Expected a key=value pair, got '{arg!s}'"
216                )
217
218            value = self.__parse_value(val)
219            optpath = key.split('.')
220            curpath = []
221            for path in optpath[:-1]:
222                curpath.append(path)
223                obj = parent.get(path, {})
224                if not isinstance(obj, dict):
225                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
226                    raise QMPShellError(msg.format('.'.join(curpath)))
227                parent[path] = obj
228                parent = obj
229            if optpath[-1] in parent:
230                if isinstance(parent[optpath[-1]], dict):
231                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
232                    raise QMPShellError(msg.format('.'.join(curpath)))
233                raise QMPShellError(f'Cannot set "{key}" multiple times')
234            parent[optpath[-1]] = value
235
236    def __build_cmd(self, cmdline: str) -> Optional[QMPMessage]:
237        """
238        Build a QMP input object from a user provided command-line in the
239        following format:
240
241            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
242        """
243        argument_regex = r'''(?:[^\s"']|"(?:\\.|[^"])*"|'(?:\\.|[^'])*')+'''
244        cmdargs = re.findall(argument_regex, cmdline)
245        qmpcmd: QMPMessage
246
247        # Transactional CLI entry/exit:
248        if cmdargs[0] == 'transaction(':
249            self._transmode = True
250            cmdargs.pop(0)
251        elif cmdargs[0] == ')' and self._transmode:
252            self._transmode = False
253            if len(cmdargs) > 1:
254                msg = 'Unexpected input after close of Transaction sub-shell'
255                raise QMPShellError(msg)
256            qmpcmd = {
257                'execute': 'transaction',
258                'arguments': {'actions': self._actions}
259            }
260            self._actions = list()
261            return qmpcmd
262
263        # Nothing to process?
264        if not cmdargs:
265            return None
266
267        # Parse and then cache this Transactional Action
268        if self._transmode:
269            finalize = False
270            action = {'type': cmdargs[0], 'data': {}}
271            if cmdargs[-1] == ')':
272                cmdargs.pop(-1)
273                finalize = True
274            self.__cli_expr(cmdargs[1:], action['data'])
275            self._actions.append(action)
276            return self.__build_cmd(')') if finalize else None
277
278        # Standard command: parse and return it to be executed.
279        qmpcmd = {'execute': cmdargs[0], 'arguments': {}}
280        self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
281        return qmpcmd
282
283    def _print(self, qmp_message: object) -> None:
284        jsobj = json.dumps(qmp_message,
285                           indent=4 if self.pretty else None,
286                           sort_keys=self.pretty)
287        print(str(jsobj))
288
289    def _execute_cmd(self, cmdline: str) -> bool:
290        try:
291            qmpcmd = self.__build_cmd(cmdline)
292        except Exception as err:
293            print('Error while parsing command line: %s' % err)
294            print('command format: <command-name> ', end=' ')
295            print('[arg-name1=arg1] ... [arg-nameN=argN]')
296            return True
297        # For transaction mode, we may have just cached the action:
298        if qmpcmd is None:
299            return True
300        if self.verbose:
301            self._print(qmpcmd)
302        resp = self.cmd_obj(qmpcmd)
303        if resp is None:
304            print('Disconnected')
305            return False
306        self._print(resp)
307        return True
308
309    def connect(self, negotiate: bool = True) -> None:
310        self._greeting = super().connect(negotiate)
311        self.__completer_setup()
312
313    def show_banner(self,
314                    msg: str = 'Welcome to the QMP low-level shell!') -> None:
315        print(msg)
316        if not self._greeting:
317            print('Connected')
318            return
319        version = self._greeting['QMP']['version']['qemu']
320        print("Connected to QEMU {major}.{minor}.{micro}\n".format(**version))
321
322    @property
323    def prompt(self) -> str:
324        if self._transmode:
325            return 'TRANS> '
326        return '(QEMU) '
327
328    def read_exec_command(self) -> bool:
329        """
330        Read and execute a command.
331
332        @return True if execution was ok, return False if disconnected.
333        """
334        try:
335            cmdline = input(self.prompt)
336        except EOFError:
337            print()
338            return False
339
340        if cmdline == '':
341            for event in self.get_events():
342                print(event)
343            self.clear_events()
344            return True
345
346        return self._execute_cmd(cmdline)
347
348    def repl(self) -> Iterator[None]:
349        self.show_banner()
350        while self.read_exec_command():
351            yield
352        self.close()
353
354
355class HMPShell(QMPShell):
356    def __init__(self, address: qmp.SocketAddrT,
357                 pretty: bool = False, verbose: bool = False):
358        super().__init__(address, pretty, verbose)
359        self.__cpu_index = 0
360
361    def __cmd_completion(self) -> None:
362        for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
363            if cmd and cmd[0] != '[' and cmd[0] != '\t':
364                name = cmd.split()[0]  # drop help text
365                if name == 'info':
366                    continue
367                if name.find('|') != -1:
368                    # Command in the form 'foobar|f' or 'f|foobar', take the
369                    # full name
370                    opt = name.split('|')
371                    if len(opt[0]) == 1:
372                        name = opt[1]
373                    else:
374                        name = opt[0]
375                self._completer.append(name)
376                self._completer.append('help ' + name)  # help completion
377
378    def __info_completion(self) -> None:
379        for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
380            if cmd:
381                self._completer.append('info ' + cmd.split()[1])
382
383    def __other_completion(self) -> None:
384        # special cases
385        self._completer.append('help info')
386
387    def _fill_completion(self) -> None:
388        self.__cmd_completion()
389        self.__info_completion()
390        self.__other_completion()
391
392    def __cmd_passthrough(self, cmdline: str,
393                          cpu_index: int = 0) -> QMPMessage:
394        return self.cmd_obj({
395            'execute': 'human-monitor-command',
396            'arguments': {
397                'command-line': cmdline,
398                'cpu-index': cpu_index
399            }
400        })
401
402    def _execute_cmd(self, cmdline: str) -> bool:
403        if cmdline.split()[0] == "cpu":
404            # trap the cpu command, it requires special setting
405            try:
406                idx = int(cmdline.split()[1])
407                if 'return' not in self.__cmd_passthrough('info version', idx):
408                    print('bad CPU index')
409                    return True
410                self.__cpu_index = idx
411            except ValueError:
412                print('cpu command takes an integer argument')
413                return True
414        resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
415        if resp is None:
416            print('Disconnected')
417            return False
418        assert 'return' in resp or 'error' in resp
419        if 'return' in resp:
420            # Success
421            if len(resp['return']) > 0:
422                print(resp['return'], end=' ')
423        else:
424            # Error
425            print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
426        return True
427
428    def show_banner(self, msg: str = 'Welcome to the HMP shell!') -> None:
429        QMPShell.show_banner(self, msg)
430
431
432def die(msg: str) -> NoReturn:
433    sys.stderr.write('ERROR: %s\n' % msg)
434    sys.exit(1)
435
436
437def main() -> None:
438    parser = argparse.ArgumentParser()
439    parser.add_argument('-H', '--hmp', action='store_true',
440                        help='Use HMP interface')
441    parser.add_argument('-N', '--skip-negotiation', action='store_true',
442                        help='Skip negotiate (for qemu-ga)')
443    parser.add_argument('-v', '--verbose', action='store_true',
444                        help='Verbose (echo commands sent and received)')
445    parser.add_argument('-p', '--pretty', action='store_true',
446                        help='Pretty-print JSON')
447
448    default_server = os.environ.get('QMP_SOCKET')
449    parser.add_argument('qmp_server', action='store',
450                        default=default_server,
451                        help='< UNIX socket path | TCP address:port >')
452
453    args = parser.parse_args()
454    if args.qmp_server is None:
455        parser.error("QMP socket or TCP address must be specified")
456
457    shell_class = HMPShell if args.hmp else QMPShell
458
459    try:
460        address = shell_class.parse_address(args.qmp_server)
461    except qmp.QMPBadPortError:
462        parser.error(f"Bad port number: {args.qmp_server}")
463        return  # pycharm doesn't know error() is noreturn
464
465    with shell_class(address, args.pretty, args.verbose) as qemu:
466        try:
467            qemu.connect(negotiate=not args.skip_negotiation)
468        except qmp.QMPConnectError:
469            die("Didn't get QMP greeting message")
470        except qmp.QMPCapabilitiesError:
471            die("Couldn't negotiate capabilities")
472        except OSError as err:
473            die(f"Couldn't connect to {args.qmp_server}: {err!s}")
474
475        for _ in qemu.repl():
476            pass
477
478
479if __name__ == '__main__':
480    main()
481