xref: /qemu/scripts/qmp/qmp-shell (revision abff1abf) 
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.
67
68import json
69import ast
70import readline
71import sys
72import os
73import errno
74import atexit
75import re
76
77sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
78from qemu import qmp
79
80class QMPCompleter(list):
81    def complete(self, text, state):
82        for cmd in self:
83            if cmd.startswith(text):
84                if not state:
85                    return cmd
86                else:
87                    state -= 1
88
89class QMPShellError(Exception):
90    pass
91
92class QMPShellBadPort(QMPShellError):
93    pass
94
95class FuzzyJSON(ast.NodeTransformer):
96    '''This extension of ast.NodeTransformer filters literal "true/false/null"
97    values in an AST and replaces them by proper "True/False/None" values that
98    Python can properly evaluate.'''
99    def visit_Name(self, node):
100        if node.id == 'true':
101            node.id = 'True'
102        if node.id == 'false':
103            node.id = 'False'
104        if node.id == 'null':
105            node.id = 'None'
106        return node
107
108# TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
109#       _execute_cmd()). Let's design a better one.
110class QMPShell(qmp.QEMUMonitorProtocol):
111    def __init__(self, address, pretty=False):
112        super(QMPShell, self).__init__(self.__get_address(address))
113        self._greeting = None
114        self._completer = None
115        self._pretty = pretty
116        self._transmode = False
117        self._actions = list()
118        self._histfile = os.path.join(os.path.expanduser('~'),
119                                      '.qmp-shell_history')
120
121    def __get_address(self, arg):
122        """
123        Figure out if the argument is in the port:host form, if it's not it's
124        probably a file path.
125        """
126        addr = arg.split(':')
127        if len(addr) == 2:
128            try:
129                port = int(addr[1])
130            except ValueError:
131                raise QMPShellBadPort
132            return ( addr[0], port )
133        # socket path
134        return arg
135
136    def _fill_completion(self):
137        cmds = self.cmd('query-commands')
138        if 'error' in cmds:
139            return
140        for cmd in cmds['return']:
141            self._completer.append(cmd['name'])
142
143    def __completer_setup(self):
144        self._completer = QMPCompleter()
145        self._fill_completion()
146        readline.set_history_length(1024)
147        readline.set_completer(self._completer.complete)
148        readline.parse_and_bind("tab: complete")
149        # XXX: default delimiters conflict with some command names (eg. query-),
150        # clearing everything as it doesn't seem to matter
151        readline.set_completer_delims('')
152        try:
153            readline.read_history_file(self._histfile)
154        except Exception as e:
155            if isinstance(e, IOError) and e.errno == errno.ENOENT:
156                # File not found. No problem.
157                pass
158            else:
159                print("Failed to read history '%s'; %s" % (self._histfile, e))
160        atexit.register(self.__save_history)
161
162    def __save_history(self):
163        try:
164            readline.write_history_file(self._histfile)
165        except Exception as e:
166            print("Failed to save history file '%s'; %s" % (self._histfile, e))
167
168    def __parse_value(self, val):
169        try:
170            return int(val)
171        except ValueError:
172            pass
173
174        if val.lower() == 'true':
175            return True
176        if val.lower() == 'false':
177            return False
178        if val.startswith(('{', '[')):
179            # Try first as pure JSON:
180            try:
181                return json.loads(val)
182            except ValueError:
183                pass
184            # Try once again as FuzzyJSON:
185            try:
186                st = ast.parse(val, mode='eval')
187                return ast.literal_eval(FuzzyJSON().visit(st))
188            except SyntaxError:
189                pass
190            except ValueError:
191                pass
192        return val
193
194    def __cli_expr(self, tokens, parent):
195        for arg in tokens:
196            (key, sep, val) = arg.partition('=')
197            if sep != '=':
198                raise QMPShellError("Expected a key=value pair, got '%s'" % arg)
199
200            value = self.__parse_value(val)
201            optpath = key.split('.')
202            curpath = []
203            for p in optpath[:-1]:
204                curpath.append(p)
205                d = parent.get(p, {})
206                if type(d) is not dict:
207                    raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
208                parent[p] = d
209                parent = d
210            if optpath[-1] in parent:
211                if type(parent[optpath[-1]]) is dict:
212                    raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
213                else:
214                    raise QMPShellError('Cannot set "%s" multiple times' % key)
215            parent[optpath[-1]] = value
216
217    def __build_cmd(self, cmdline):
218        """
219        Build a QMP input object from a user provided command-line in the
220        following format:
221
222            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
223        """
224        cmdargs = re.findall(r'''(?:[^\s"']|"(?:\\.|[^"])*"|'(?:\\.|[^'])*')+''', cmdline)
225
226        # Transactional CLI entry/exit:
227        if cmdargs[0] == 'transaction(':
228            self._transmode = True
229            cmdargs.pop(0)
230        elif cmdargs[0] == ')' and self._transmode:
231            self._transmode = False
232            if len(cmdargs) > 1:
233                raise QMPShellError("Unexpected input after close of Transaction sub-shell")
234            qmpcmd = { 'execute': 'transaction',
235                       'arguments': { 'actions': self._actions } }
236            self._actions = list()
237            return qmpcmd
238
239        # Nothing to process?
240        if not cmdargs:
241            return None
242
243        # Parse and then cache this Transactional Action
244        if self._transmode:
245            finalize = False
246            action = { 'type': cmdargs[0], 'data': {} }
247            if cmdargs[-1] == ')':
248                cmdargs.pop(-1)
249                finalize = True
250            self.__cli_expr(cmdargs[1:], action['data'])
251            self._actions.append(action)
252            return self.__build_cmd(')') if finalize else None
253
254        # Standard command: parse and return it to be executed.
255        qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
256        self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
257        return qmpcmd
258
259    def _print(self, qmp):
260        indent = None
261        if self._pretty:
262            indent = 4
263        jsobj = json.dumps(qmp, indent=indent)
264        print(str(jsobj))
265
266    def _execute_cmd(self, cmdline):
267        try:
268            qmpcmd = self.__build_cmd(cmdline)
269        except Exception as e:
270            print('Error while parsing command line: %s' % e)
271            print('command format: <command-name> ', end=' ')
272            print('[arg-name1=arg1] ... [arg-nameN=argN]')
273            return True
274        # For transaction mode, we may have just cached the action:
275        if qmpcmd is None:
276            return True
277        if self._verbose:
278            self._print(qmpcmd)
279        resp = self.cmd_obj(qmpcmd)
280        if resp is None:
281            print('Disconnected')
282            return False
283        self._print(resp)
284        return True
285
286    def connect(self, negotiate):
287        self._greeting = super(QMPShell, self).connect(negotiate)
288        self.__completer_setup()
289
290    def show_banner(self, msg='Welcome to the QMP low-level shell!'):
291        print(msg)
292        if not self._greeting:
293            print('Connected')
294            return
295        version = self._greeting['QMP']['version']['qemu']
296        print('Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro']))
297
298    def get_prompt(self):
299        if self._transmode:
300            return "TRANS> "
301        return "(QEMU) "
302
303    def read_exec_command(self, prompt):
304        """
305        Read and execute a command.
306
307        @return True if execution was ok, return False if disconnected.
308        """
309        try:
310            cmdline = input(prompt)
311        except EOFError:
312            print()
313            return False
314        if cmdline == '':
315            for ev in self.get_events():
316                print(ev)
317            self.clear_events()
318            return True
319        else:
320            return self._execute_cmd(cmdline)
321
322    def set_verbosity(self, verbose):
323        self._verbose = verbose
324
325class HMPShell(QMPShell):
326    def __init__(self, address):
327        QMPShell.__init__(self, address)
328        self.__cpu_index = 0
329
330    def __cmd_completion(self):
331        for cmd in self.__cmd_passthrough('help')['return'].split('\r\n'):
332            if cmd and cmd[0] != '[' and cmd[0] != '\t':
333                name = cmd.split()[0] # drop help text
334                if name == 'info':
335                    continue
336                if name.find('|') != -1:
337                    # Command in the form 'foobar|f' or 'f|foobar', take the
338                    # full name
339                    opt = name.split('|')
340                    if len(opt[0]) == 1:
341                        name = opt[1]
342                    else:
343                        name = opt[0]
344                self._completer.append(name)
345                self._completer.append('help ' + name) # help completion
346
347    def __info_completion(self):
348        for cmd in self.__cmd_passthrough('info')['return'].split('\r\n'):
349            if cmd:
350                self._completer.append('info ' + cmd.split()[1])
351
352    def __other_completion(self):
353        # special cases
354        self._completer.append('help info')
355
356    def _fill_completion(self):
357        self.__cmd_completion()
358        self.__info_completion()
359        self.__other_completion()
360
361    def __cmd_passthrough(self, cmdline, cpu_index = 0):
362        return self.cmd_obj({ 'execute': 'human-monitor-command', 'arguments':
363                              { 'command-line': cmdline,
364                                'cpu-index': cpu_index } })
365
366    def _execute_cmd(self, cmdline):
367        if cmdline.split()[0] == "cpu":
368            # trap the cpu command, it requires special setting
369            try:
370                idx = int(cmdline.split()[1])
371                if not 'return' in self.__cmd_passthrough('info version', idx):
372                    print('bad CPU index')
373                    return True
374                self.__cpu_index = idx
375            except ValueError:
376                print('cpu command takes an integer argument')
377                return True
378        resp = self.__cmd_passthrough(cmdline, self.__cpu_index)
379        if resp is None:
380            print('Disconnected')
381            return False
382        assert 'return' in resp or 'error' in resp
383        if 'return' in resp:
384            # Success
385            if len(resp['return']) > 0:
386                print(resp['return'], end=' ')
387        else:
388            # Error
389            print('%s: %s' % (resp['error']['class'], resp['error']['desc']))
390        return True
391
392    def show_banner(self):
393        QMPShell.show_banner(self, msg='Welcome to the HMP shell!')
394
395def die(msg):
396    sys.stderr.write('ERROR: %s\n' % msg)
397    sys.exit(1)
398
399def fail_cmdline(option=None):
400    if option:
401        sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
402    sys.stderr.write('qmp-shell [ -v ] [ -p ] [ -H ] [ -N ] < UNIX socket path> | < TCP address:port >\n')
403    sys.stderr.write('    -v     Verbose (echo command sent and received)\n')
404    sys.stderr.write('    -p     Pretty-print JSON\n')
405    sys.stderr.write('    -H     Use HMP interface\n')
406    sys.stderr.write('    -N     Skip negotiate (for qemu-ga)\n')
407    sys.exit(1)
408
409def main():
410    addr = ''
411    qemu = None
412    hmp = False
413    pretty = False
414    verbose = False
415    negotiate = True
416
417    try:
418        for arg in sys.argv[1:]:
419            if arg == "-H":
420                if qemu is not None:
421                    fail_cmdline(arg)
422                hmp = True
423            elif arg == "-p":
424                pretty = True
425            elif arg == "-N":
426                negotiate = False
427            elif arg == "-v":
428                verbose = True
429            else:
430                if qemu is not None:
431                    fail_cmdline(arg)
432                if hmp:
433                    qemu = HMPShell(arg)
434                else:
435                    qemu = QMPShell(arg, pretty)
436                addr = arg
437
438        if qemu is None:
439            fail_cmdline()
440    except QMPShellBadPort:
441        die('bad port number in command-line')
442
443    try:
444        qemu.connect(negotiate)
445    except qmp.QMPConnectError:
446        die('Didn\'t get QMP greeting message')
447    except qmp.QMPCapabilitiesError:
448        die('Could not negotiate capabilities')
449    except qemu.error:
450        die('Could not connect to %s' % addr)
451
452    qemu.show_banner()
453    qemu.set_verbosity(verbose)
454    while qemu.read_exec_command(qemu.get_prompt()):
455        pass
456    qemu.close()
457
458if __name__ == '__main__':
459    main()
460