xref: /qemu/scripts/qmp/qmp-shell (revision be19c6a7126e5a463b3ef1ea23b985f6dc627a7a) 
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
133# TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
134#       _execute_cmd()). Let's design a better one.
135class QMPShell(qmp.QEMUMonitorProtocol):
136    def __init__(self, address: qmp.SocketAddrT,
137                 pretty: bool = False, verbose: bool = False):
138        super().__init__(address)
139        self._greeting: Optional[QMPMessage] = None
140        self._completer = QMPCompleter()
141        self._transmode = False
142        self._actions: List[QMPMessage] = []
143        self._histfile = os.path.join(os.path.expanduser('~'),
144                                      '.qmp-shell_history')
145        self.pretty = pretty
146        self.verbose = verbose
147
148    def close(self) -> None:
149        # Hook into context manager of parent to save shell history.
150        self._save_history()
151        super().close()
152
153    def _fill_completion(self) -> None:
154        cmds = self.cmd('query-commands')
155        if 'error' in cmds:
156            return
157        for cmd in cmds['return']:
158            self._completer.append(cmd['name'])
159
160    def __completer_setup(self) -> None:
161        self._completer = QMPCompleter()
162        self._fill_completion()
163        readline.set_history_length(1024)
164        readline.set_completer(self._completer.complete)
165        readline.parse_and_bind("tab: complete")
166        # NB: default delimiters conflict with some command names
167        # (eg. query-), clearing everything as it doesn't seem to matter
168        readline.set_completer_delims('')
169        try:
170            readline.read_history_file(self._histfile)
171        except FileNotFoundError:
172            pass
173        except IOError as err:
174            msg = f"Failed to read history '{self._histfile}': {err!s}"
175            LOG.warning(msg)
176
177    def _save_history(self) -> None:
178        try:
179            readline.write_history_file(self._histfile)
180        except IOError as err:
181            msg = f"Failed to save history file '{self._histfile}': {err!s}"
182            LOG.warning(msg)
183
184    @classmethod
185    def __parse_value(cls, val: str) -> object:
186        try:
187            return int(val)
188        except ValueError:
189            pass
190
191        if val.lower() == 'true':
192            return True
193        if val.lower() == 'false':
194            return False
195        if val.startswith(('{', '[')):
196            # Try first as pure JSON:
197            try:
198                return json.loads(val)
199            except ValueError:
200                pass
201            # Try once again as FuzzyJSON:
202            try:
203                tree = ast.parse(val, mode='eval')
204                transformed = FuzzyJSON().visit(tree)
205                return ast.literal_eval(transformed)
206            except (SyntaxError, ValueError):
207                pass
208        return val
209
210    def __cli_expr(self,
211                   tokens: Sequence[str],
212                   parent: qmp.QMPObject) -> None:
213        for arg in tokens:
214            (key, sep, val) = arg.partition('=')
215            if sep != '=':
216                raise QMPShellError(
217                    f"Expected a key=value pair, got '{arg!s}'"
218                )
219
220            value = self.__parse_value(val)
221            optpath = key.split('.')
222            curpath = []
223            for path in optpath[:-1]:
224                curpath.append(path)
225                obj = parent.get(path, {})
226                if not isinstance(obj, dict):
227                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
228                    raise QMPShellError(msg.format('.'.join(curpath)))
229                parent[path] = obj
230                parent = obj
231            if optpath[-1] in parent:
232                if isinstance(parent[optpath[-1]], dict):
233                    msg = 'Cannot use "{:s}" as both leaf and non-leaf key'
234                    raise QMPShellError(msg.format('.'.join(curpath)))
235                raise QMPShellError(f'Cannot set "{key}" multiple times')
236            parent[optpath[-1]] = value
237
238    def __build_cmd(self, cmdline: str) -> Optional[QMPMessage]:
239        """
240        Build a QMP input object from a user provided command-line in the
241        following format:
242
243            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
244        """
245        argument_regex = r'''(?:[^\s"']|"(?:\\.|[^"])*"|'(?:\\.|[^'])*')+'''
246        cmdargs = re.findall(argument_regex, cmdline)
247        qmpcmd: QMPMessage
248
249        # Transactional CLI entry/exit:
250        if cmdargs[0] == 'transaction(':
251            self._transmode = True
252            cmdargs.pop(0)
253        elif cmdargs[0] == ')' and self._transmode:
254            self._transmode = False
255            if len(cmdargs) > 1:
256                msg = 'Unexpected input after close of Transaction sub-shell'
257                raise QMPShellError(msg)
258            qmpcmd = {
259                'execute': 'transaction',
260                'arguments': {'actions': self._actions}
261            }
262            self._actions = list()
263            return qmpcmd
264
265        # Nothing to process?
266        if not cmdargs:
267            return None
268
269        # Parse and then cache this Transactional Action
270        if self._transmode:
271            finalize = False
272            action = {'type': cmdargs[0], 'data': {}}
273            if cmdargs[-1] == ')':
274                cmdargs.pop(-1)
275                finalize = True
276            self.__cli_expr(cmdargs[1:], action['data'])
277            self._actions.append(action)
278            return self.__build_cmd(')') if finalize else None
279
280        # Standard command: parse and return it to be executed.
281        qmpcmd = {'execute': cmdargs[0], 'arguments': {}}
282        self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
283        return qmpcmd
284
285    def _print(self, qmp_message: object) -> None:
286        jsobj = json.dumps(qmp_message,
287                           indent=4 if self.pretty else None,
288                           sort_keys=self.pretty)
289        print(str(jsobj))
290
291    def _execute_cmd(self, cmdline: str) -> bool:
292        try:
293            qmpcmd = self.__build_cmd(cmdline)
294        except Exception as err:
295            print('Error while parsing command line: %s' % err)
296            print('command format: <command-name> ', end=' ')
297            print('[arg-name1=arg1] ... [arg-nameN=argN]')
298            return True
299        # For transaction mode, we may have just cached the action:
300        if qmpcmd is None:
301            return True
302        if self.verbose:
303            self._print(qmpcmd)
304        resp = self.cmd_obj(qmpcmd)
305        if resp is None:
306            print('Disconnected')
307            return False
308        self._print(resp)
309        return True
310
311    def connect(self, negotiate: bool = True) -> None:
312        self._greeting = super().connect(negotiate)
313        self.__completer_setup()
314
315    def show_banner(self,
316                    msg: str = 'Welcome to the QMP low-level shell!') -> None:
317        print(msg)
318        if not self._greeting:
319            print('Connected')
320            return
321        version = self._greeting['QMP']['version']['qemu']
322        print("Connected to QEMU {major}.{minor}.{micro}\n".format(**version))
323
324    @property
325    def prompt(self) -> str:
326        if self._transmode:
327            return 'TRANS> '
328        return '(QEMU) '
329
330    def read_exec_command(self) -> bool:
331        """
332        Read and execute a command.
333
334        @return True if execution was ok, return False if disconnected.
335        """
336        try:
337            cmdline = input(self.prompt)
338        except EOFError:
339            print()
340            return False
341
342        if cmdline == '':
343            for event in self.get_events():
344                print(event)
345            self.clear_events()
346            return True
347
348        return self._execute_cmd(cmdline)
349
350    def repl(self) -> Iterator[None]:
351        self.show_banner()
352        while self.read_exec_command():
353            yield
354        self.close()
355
356
357class HMPShell(QMPShell):
358    def __init__(self, address: qmp.SocketAddrT,
359                 pretty: bool = False, verbose: bool = False):
360        super().__init__(address, pretty, verbose)
361        self.__cpu_index = 0
362
363    def __cmd_completion(self) -> None:
364        for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
365            if cmd and cmd[0] != '[' and cmd[0] != '\t':
366                name = cmd.split()[0]  # drop help text
367                if name == 'info':
368                    continue
369                if name.find('|') != -1:
370                    # Command in the form 'foobar|f' or 'f|foobar', take the
371                    # full name
372                    opt = name.split('|')
373                    if len(opt[0]) == 1:
374                        name = opt[1]
375                    else:
376                        name = opt[0]
377                self._completer.append(name)
378                self._completer.append('help ' + name)  # help completion
379
380    def __info_completion(self) -> None:
381        for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
382            if cmd:
383                self._completer.append('info ' + cmd.split()[1])
384
385    def __other_completion(self) -> None:
386        # special cases
387        self._completer.append('help info')
388
389    def _fill_completion(self) -> None:
390        self.__cmd_completion()
391        self.__info_completion()
392        self.__other_completion()
393
394    def __cmd_passthrough(self, cmdline: str,
395                          cpu_index: int = 0) -> QMPMessage:
396        return self.cmd_obj({
397            'execute': 'human-monitor-command',
398            'arguments': {
399                'command-line': cmdline,
400                'cpu-index': cpu_index
401            }
402        })
403
404    def _execute_cmd(self, cmdline: str) -> bool:
405        if cmdline.split()[0] == "cpu":
406            # trap the cpu command, it requires special setting
407            try:
408                idx = int(cmdline.split()[1])
409                if 'return' not in self.__cmd_passthrough('info version', idx):
410                    print('bad CPU index')
411                    return True
412                self.__cpu_index = idx
413            except ValueError:
414                print('cpu command takes an integer argument')
415                return True
416        resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
417        if resp is None:
418            print('Disconnected')
419            return False
420        assert 'return' in resp or 'error' in resp
421        if 'return' in resp:
422            # Success
423            if len(resp['return']) > 0:
424                print(resp['return'], end=' ')
425        else:
426            # Error
427            print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
428        return True
429
430    def show_banner(self, msg: str = 'Welcome to the HMP shell!') -> None:
431        QMPShell.show_banner(self, msg)
432
433
434def die(msg: str) -> NoReturn:
435    sys.stderr.write('ERROR: %s\n' % msg)
436    sys.exit(1)
437
438
439def main() -> None:
440    parser = argparse.ArgumentParser()
441    parser.add_argument('-H', '--hmp', action='store_true',
442                        help='Use HMP interface')
443    parser.add_argument('-N', '--skip-negotiation', action='store_true',
444                        help='Skip negotiate (for qemu-ga)')
445    parser.add_argument('-v', '--verbose', action='store_true',
446                        help='Verbose (echo commands sent and received)')
447    parser.add_argument('-p', '--pretty', action='store_true',
448                        help='Pretty-print JSON')
449
450    default_server = os.environ.get('QMP_SOCKET')
451    parser.add_argument('qmp_server', action='store',
452                        default=default_server,
453                        help='< UNIX socket path | TCP address:port >')
454
455    args = parser.parse_args()
456    if args.qmp_server is None:
457        parser.error("QMP socket or TCP address must be specified")
458
459    shell_class = HMPShell if args.hmp else QMPShell
460
461    try:
462        address = shell_class.parse_address(args.qmp_server)
463    except qmp.QMPBadPortError:
464        parser.error(f"Bad port number: {args.qmp_server}")
465        return  # pycharm doesn't know error() is noreturn
466
467    with shell_class(address, args.pretty, args.verbose) as qemu:
468        try:
469            qemu.connect(negotiate=not args.skip_negotiation)
470        except qmp.QMPConnectError:
471            die("Didn't get QMP greeting message")
472        except qmp.QMPCapabilitiesError:
473            die("Couldn't negotiate capabilities")
474        except OSError as err:
475            die(f"Couldn't connect to {args.qmp_server}: {err!s}")
476
477        for _ in qemu.repl():
478            pass
479
480
481if __name__ == '__main__':
482    main()
483