xref: /openbmc/qemu/scripts/qapi/expr.py (revision c145bfda18f63c67f77ecbedbbd5a68fed2c4a4a) 
1# -*- coding: utf-8 -*-
2#
3# Check (context-free) QAPI schema expression structure
4#
5# Copyright IBM, Corp. 2011
6# Copyright (c) 2013-2019 Red Hat Inc.
7#
8# Authors:
9#  Anthony Liguori <aliguori@us.ibm.com>
10#  Markus Armbruster <armbru@redhat.com>
11#  Eric Blake <eblake@redhat.com>
12#  Marc-André Lureau <marcandre.lureau@redhat.com>
13#
14# This work is licensed under the terms of the GNU GPL, version 2.
15# See the COPYING file in the top-level directory.
16
17import re
18from collections import OrderedDict
19from qapi.common import c_name
20from qapi.error import QAPISemError
21
22
23# Names must be letters, numbers, -, and _.  They must start with letter,
24# except for downstream extensions which must start with __RFQDN_.
25# Dots are only valid in the downstream extension prefix.
26valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
27                        '[a-zA-Z][a-zA-Z0-9_-]*$')
28
29
30def check_name_is_str(name, info, source):
31    if not isinstance(name, str):
32        raise QAPISemError(info, "%s requires a string name" % source)
33
34
35def check_name_str(name, info, source,
36                   allow_optional=False, enum_member=False,
37                   permit_upper=False):
38    global valid_name
39    membername = name
40
41    if allow_optional and name.startswith('*'):
42        membername = name[1:]
43    # Enum members can start with a digit, because the generated C
44    # code always prefixes it with the enum name
45    if enum_member and membername[0].isdigit():
46        membername = 'D' + membername
47    # Reserve the entire 'q_' namespace for c_name(), and for 'q_empty'
48    # and 'q_obj_*' implicit type names.
49    if not valid_name.match(membername) or \
50       c_name(membername, False).startswith('q_'):
51        raise QAPISemError(info, "%s has an invalid name" % source)
52    if not permit_upper and name.lower() != name:
53        raise QAPISemError(
54            info, "%s uses uppercase in name" % source)
55    assert not membername.startswith('*')
56
57
58def check_defn_name_str(name, info, meta):
59    check_name_str(name, info, meta, permit_upper=True)
60    if name.endswith('Kind') or name.endswith('List'):
61        raise QAPISemError(
62            info, "%s name should not end in '%s'" % (meta, name[-4:]))
63
64
65def check_keys(value, info, source, required, optional):
66
67    def pprint(elems):
68        return ', '.join("'" + e + "'" for e in sorted(elems))
69
70    missing = set(required) - set(value)
71    if missing:
72        raise QAPISemError(
73            info,
74            "%s misses key%s %s"
75            % (source, 's' if len(missing) > 1 else '',
76               pprint(missing)))
77    allowed = set(required + optional)
78    unknown = set(value) - allowed
79    if unknown:
80        raise QAPISemError(
81            info,
82            "%s has unknown key%s %s\nValid keys are %s."
83            % (source, 's' if len(unknown) > 1 else '',
84               pprint(unknown), pprint(allowed)))
85
86
87def check_flags(expr, info):
88    for key in ['gen', 'success-response']:
89        if key in expr and expr[key] is not False:
90            raise QAPISemError(
91                info, "flag '%s' may only use false value" % key)
92    for key in ['boxed', 'allow-oob', 'allow-preconfig']:
93        if key in expr and expr[key] is not True:
94            raise QAPISemError(
95                info, "flag '%s' may only use true value" % key)
96
97
98def check_if(expr, info, source):
99
100    def check_if_str(ifcond, info):
101        if not isinstance(ifcond, str):
102            raise QAPISemError(
103                info,
104                "'if' condition of %s must be a string or a list of strings"
105                % source)
106        if ifcond.strip() == '':
107            raise QAPISemError(
108                info,
109                "'if' condition '%s' of %s makes no sense"
110                % (ifcond, source))
111
112    ifcond = expr.get('if')
113    if ifcond is None:
114        return
115    if isinstance(ifcond, list):
116        if ifcond == []:
117            raise QAPISemError(
118                info, "'if' condition [] of %s is useless" % source)
119        for elt in ifcond:
120            check_if_str(elt, info)
121    else:
122        check_if_str(ifcond, info)
123        expr['if'] = [ifcond]
124
125
126def normalize_members(members):
127    if isinstance(members, OrderedDict):
128        for key, arg in members.items():
129            if isinstance(arg, dict):
130                continue
131            members[key] = {'type': arg}
132
133
134def check_type(value, info, source,
135               allow_array=False, allow_dict=False):
136    if value is None:
137        return
138
139    # Array type
140    if isinstance(value, list):
141        if not allow_array:
142            raise QAPISemError(info, "%s cannot be an array" % source)
143        if len(value) != 1 or not isinstance(value[0], str):
144            raise QAPISemError(info,
145                               "%s: array type must contain single type name" %
146                               source)
147        return
148
149    # Type name
150    if isinstance(value, str):
151        return
152
153    # Anonymous type
154
155    if not allow_dict:
156        raise QAPISemError(info, "%s should be a type name" % source)
157
158    if not isinstance(value, OrderedDict):
159        raise QAPISemError(info,
160                           "%s should be an object or type name" % source)
161
162    permit_upper = allow_dict in info.pragma.name_case_whitelist
163
164    # value is a dictionary, check that each member is okay
165    for (key, arg) in value.items():
166        key_source = "%s member '%s'" % (source, key)
167        check_name_str(key, info, key_source,
168                       allow_optional=True, permit_upper=permit_upper)
169        if c_name(key, False) == 'u' or c_name(key, False).startswith('has_'):
170            raise QAPISemError(info, "%s uses reserved name" % key_source)
171        check_keys(arg, info, key_source, ['type'], ['if'])
172        check_if(arg, info, key_source)
173        check_type(arg['type'], info, key_source, allow_array=True)
174
175
176def normalize_features(features):
177    if isinstance(features, list):
178        features[:] = [f if isinstance(f, dict) else {'name': f}
179                       for f in features]
180
181
182def check_features(features, info):
183    if features is None:
184        return
185    if not isinstance(features, list):
186        raise QAPISemError(info, "'features' must be an array")
187    for f in features:
188        source = "'features' member"
189        assert isinstance(f, dict)
190        check_keys(f, info, source, ['name'], ['if'])
191        check_name_is_str(f['name'], info, source)
192        source = "%s '%s'" % (source, f['name'])
193        check_name_str(f['name'], info, source)
194        check_if(f, info, source)
195
196
197def normalize_enum(expr):
198    if isinstance(expr['data'], list):
199        expr['data'] = [m if isinstance(m, dict) else {'name': m}
200                        for m in expr['data']]
201
202
203def check_enum(expr, info):
204    name = expr['enum']
205    members = expr['data']
206    prefix = expr.get('prefix')
207
208    if not isinstance(members, list):
209        raise QAPISemError(info, "'data' must be an array")
210    if prefix is not None and not isinstance(prefix, str):
211        raise QAPISemError(info, "'prefix' must be a string")
212
213    permit_upper = name in info.pragma.name_case_whitelist
214
215    for member in members:
216        source = "'data' member"
217        check_keys(member, info, source, ['name'], ['if'])
218        check_name_is_str(member['name'], info, source)
219        source = "%s '%s'" % (source, member['name'])
220        check_name_str(member['name'], info, source,
221                       enum_member=True, permit_upper=permit_upper)
222        check_if(member, info, source)
223
224
225def check_struct(expr, info):
226    name = expr['struct']
227    members = expr['data']
228
229    check_type(members, info, "'data'", allow_dict=name)
230    check_type(expr.get('base'), info, "'base'")
231    check_features(expr.get('features'), info)
232
233
234def check_union(expr, info):
235    name = expr['union']
236    base = expr.get('base')
237    discriminator = expr.get('discriminator')
238    members = expr['data']
239
240    if discriminator is None:   # simple union
241        if base is not None:
242            raise QAPISemError(info, "'base' requires 'discriminator'")
243    else:                       # flat union
244        check_type(base, info, "'base'", allow_dict=name)
245        if not base:
246            raise QAPISemError(info, "'discriminator' requires 'base'")
247        check_name_is_str(discriminator, info, "'discriminator'")
248
249    for (key, value) in members.items():
250        source = "'data' member '%s'" % key
251        check_name_str(key, info, source)
252        check_keys(value, info, source, ['type'], ['if'])
253        check_if(value, info, source)
254        check_type(value['type'], info, source, allow_array=not base)
255
256
257def check_alternate(expr, info):
258    members = expr['data']
259
260    if len(members) == 0:
261        raise QAPISemError(info, "'data' must not be empty")
262    for (key, value) in members.items():
263        source = "'data' member '%s'" % key
264        check_name_str(key, info, source)
265        check_keys(value, info, source, ['type'], ['if'])
266        check_if(value, info, source)
267        check_type(value['type'], info, source)
268
269
270def check_command(expr, info):
271    args = expr.get('data')
272    rets = expr.get('returns')
273    boxed = expr.get('boxed', False)
274
275    if boxed and args is None:
276        raise QAPISemError(info, "'boxed': true requires 'data'")
277    check_type(args, info, "'data'", allow_dict=not boxed)
278    check_type(rets, info, "'returns'", allow_array=True)
279    check_features(expr.get('features'), info)
280
281
282def check_event(expr, info):
283    args = expr.get('data')
284    boxed = expr.get('boxed', False)
285
286    if boxed and args is None:
287        raise QAPISemError(info, "'boxed': true requires 'data'")
288    check_type(args, info, "'data'", allow_dict=not boxed)
289
290
291def check_exprs(exprs):
292    for expr_elem in exprs:
293        expr = expr_elem['expr']
294        info = expr_elem['info']
295        doc = expr_elem.get('doc')
296
297        if 'include' in expr:
298            continue
299
300        if 'enum' in expr:
301            meta = 'enum'
302        elif 'union' in expr:
303            meta = 'union'
304        elif 'alternate' in expr:
305            meta = 'alternate'
306        elif 'struct' in expr:
307            meta = 'struct'
308        elif 'command' in expr:
309            meta = 'command'
310        elif 'event' in expr:
311            meta = 'event'
312        else:
313            raise QAPISemError(info, "expression is missing metatype")
314
315        name = expr[meta]
316        check_name_is_str(name, info, "'%s'" % meta)
317        info.set_defn(meta, name)
318        check_defn_name_str(name, info, meta)
319
320        if doc:
321            if doc.symbol != name:
322                raise QAPISemError(
323                    info, "documentation comment is for '%s'" % doc.symbol)
324            doc.check_expr(expr)
325        elif info.pragma.doc_required:
326            raise QAPISemError(info,
327                               "documentation comment required")
328
329        if meta == 'enum':
330            check_keys(expr, info, meta,
331                       ['enum', 'data'], ['if', 'prefix'])
332            normalize_enum(expr)
333            check_enum(expr, info)
334        elif meta == 'union':
335            check_keys(expr, info, meta,
336                       ['union', 'data'],
337                       ['base', 'discriminator', 'if'])
338            normalize_members(expr.get('base'))
339            normalize_members(expr['data'])
340            check_union(expr, info)
341        elif meta == 'alternate':
342            check_keys(expr, info, meta,
343                       ['alternate', 'data'], ['if'])
344            normalize_members(expr['data'])
345            check_alternate(expr, info)
346        elif meta == 'struct':
347            check_keys(expr, info, meta,
348                       ['struct', 'data'], ['base', 'if', 'features'])
349            normalize_members(expr['data'])
350            normalize_features(expr.get('features'))
351            check_struct(expr, info)
352        elif meta == 'command':
353            check_keys(expr, info, meta,
354                       ['command'],
355                       ['data', 'returns', 'boxed', 'if', 'features',
356                        'gen', 'success-response', 'allow-oob',
357                        'allow-preconfig'])
358            normalize_members(expr.get('data'))
359            normalize_features(expr.get('features'))
360            check_command(expr, info)
361        elif meta == 'event':
362            check_keys(expr, info, meta,
363                       ['event'], ['data', 'boxed', 'if'])
364            normalize_members(expr.get('data'))
365            check_event(expr, info)
366        else:
367            assert False, 'unexpected meta type'
368
369        check_if(expr, info, meta)
370        check_flags(expr, info)
371
372    return exprs
373