xref: /qemu/scripts/qapi/expr.py (revision 27a4a30e) 
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    membername = name
39
40    if allow_optional and name.startswith('*'):
41        membername = name[1:]
42    # Enum members can start with a digit, because the generated C
43    # code always prefixes it with the enum name
44    if enum_member and membername[0].isdigit():
45        membername = 'D' + membername
46    # Reserve the entire 'q_' namespace for c_name(), and for 'q_empty'
47    # and 'q_obj_*' implicit type names.
48    if not valid_name.match(membername) or \
49       c_name(membername, False).startswith('q_'):
50        raise QAPISemError(info, "%s has an invalid name" % source)
51    if not permit_upper and name.lower() != name:
52        raise QAPISemError(
53            info, "%s uses uppercase in name" % source)
54    assert not membername.startswith('*')
55
56
57def check_defn_name_str(name, info, meta):
58    check_name_str(name, info, meta, permit_upper=True)
59    if name.endswith('Kind') or name.endswith('List'):
60        raise QAPISemError(
61            info, "%s name should not end in '%s'" % (meta, name[-4:]))
62
63
64def check_keys(value, info, source, required, optional):
65
66    def pprint(elems):
67        return ', '.join("'" + e + "'" for e in sorted(elems))
68
69    missing = set(required) - set(value)
70    if missing:
71        raise QAPISemError(
72            info,
73            "%s misses key%s %s"
74            % (source, 's' if len(missing) > 1 else '',
75               pprint(missing)))
76    allowed = set(required + optional)
77    unknown = set(value) - allowed
78    if unknown:
79        raise QAPISemError(
80            info,
81            "%s has unknown key%s %s\nValid keys are %s."
82            % (source, 's' if len(unknown) > 1 else '',
83               pprint(unknown), pprint(allowed)))
84
85
86def check_flags(expr, info):
87    for key in ['gen', 'success-response']:
88        if key in expr and expr[key] is not False:
89            raise QAPISemError(
90                info, "flag '%s' may only use false value" % key)
91    for key in ['boxed', 'allow-oob', 'allow-preconfig']:
92        if key in expr and expr[key] is not True:
93            raise QAPISemError(
94                info, "flag '%s' may only use true value" % key)
95
96
97def check_if(expr, info, source):
98
99    def check_if_str(ifcond, info):
100        if not isinstance(ifcond, str):
101            raise QAPISemError(
102                info,
103                "'if' condition of %s must be a string or a list of strings"
104                % source)
105        if ifcond.strip() == '':
106            raise QAPISemError(
107                info,
108                "'if' condition '%s' of %s makes no sense"
109                % (ifcond, source))
110
111    ifcond = expr.get('if')
112    if ifcond is None:
113        return
114    if isinstance(ifcond, list):
115        if ifcond == []:
116            raise QAPISemError(
117                info, "'if' condition [] of %s is useless" % source)
118        for elt in ifcond:
119            check_if_str(elt, info)
120    else:
121        check_if_str(ifcond, info)
122        expr['if'] = [ifcond]
123
124
125def normalize_members(members):
126    if isinstance(members, OrderedDict):
127        for key, arg in members.items():
128            if isinstance(arg, dict):
129                continue
130            members[key] = {'type': arg}
131
132
133def check_type(value, info, source,
134               allow_array=False, allow_dict=False):
135    if value is None:
136        return
137
138    # Array type
139    if isinstance(value, list):
140        if not allow_array:
141            raise QAPISemError(info, "%s cannot be an array" % source)
142        if len(value) != 1 or not isinstance(value[0], str):
143            raise QAPISemError(info,
144                               "%s: array type must contain single type name" %
145                               source)
146        return
147
148    # Type name
149    if isinstance(value, str):
150        return
151
152    # Anonymous type
153
154    if not allow_dict:
155        raise QAPISemError(info, "%s should be a type name" % source)
156
157    if not isinstance(value, OrderedDict):
158        raise QAPISemError(info,
159                           "%s should be an object or type name" % source)
160
161    permit_upper = allow_dict in info.pragma.name_case_whitelist
162
163    # value is a dictionary, check that each member is okay
164    for (key, arg) in value.items():
165        key_source = "%s member '%s'" % (source, key)
166        check_name_str(key, info, key_source,
167                       allow_optional=True, permit_upper=permit_upper)
168        if c_name(key, False) == 'u' or c_name(key, False).startswith('has_'):
169            raise QAPISemError(info, "%s uses reserved name" % key_source)
170        check_keys(arg, info, key_source, ['type'], ['if', 'features'])
171        check_if(arg, info, key_source)
172        check_features(arg.get('features'), info)
173        check_type(arg['type'], info, key_source, allow_array=True)
174
175
176def check_features(features, info):
177    if features is None:
178        return
179    if not isinstance(features, list):
180        raise QAPISemError(info, "'features' must be an array")
181    features[:] = [f if isinstance(f, dict) else {'name': f}
182                   for f in features]
183    for f in features:
184        source = "'features' member"
185        assert isinstance(f, dict)
186        check_keys(f, info, source, ['name'], ['if'])
187        check_name_is_str(f['name'], info, source)
188        source = "%s '%s'" % (source, f['name'])
189        check_name_str(f['name'], info, source)
190        check_if(f, info, source)
191
192
193def check_enum(expr, info):
194    name = expr['enum']
195    members = expr['data']
196    prefix = expr.get('prefix')
197
198    if not isinstance(members, list):
199        raise QAPISemError(info, "'data' must be an array")
200    if prefix is not None and not isinstance(prefix, str):
201        raise QAPISemError(info, "'prefix' must be a string")
202
203    permit_upper = name in info.pragma.name_case_whitelist
204
205    members[:] = [m if isinstance(m, dict) else {'name': m}
206                  for m in members]
207    for member in members:
208        source = "'data' member"
209        check_keys(member, info, source, ['name'], ['if'])
210        check_name_is_str(member['name'], info, source)
211        source = "%s '%s'" % (source, member['name'])
212        check_name_str(member['name'], info, source,
213                       enum_member=True, permit_upper=permit_upper)
214        check_if(member, info, source)
215
216
217def check_struct(expr, info):
218    name = expr['struct']
219    members = expr['data']
220
221    check_type(members, info, "'data'", allow_dict=name)
222    check_type(expr.get('base'), info, "'base'")
223
224
225def check_union(expr, info):
226    name = expr['union']
227    base = expr.get('base')
228    discriminator = expr.get('discriminator')
229    members = expr['data']
230
231    if discriminator is None:   # simple union
232        if base is not None:
233            raise QAPISemError(info, "'base' requires 'discriminator'")
234    else:                       # flat union
235        check_type(base, info, "'base'", allow_dict=name)
236        if not base:
237            raise QAPISemError(info, "'discriminator' requires 'base'")
238        check_name_is_str(discriminator, info, "'discriminator'")
239
240    for (key, value) in members.items():
241        source = "'data' member '%s'" % key
242        check_name_str(key, info, source)
243        check_keys(value, info, source, ['type'], ['if'])
244        check_if(value, info, source)
245        check_type(value['type'], info, source, allow_array=not base)
246
247
248def check_alternate(expr, info):
249    members = expr['data']
250
251    if not members:
252        raise QAPISemError(info, "'data' must not be empty")
253    for (key, value) in members.items():
254        source = "'data' member '%s'" % key
255        check_name_str(key, info, source)
256        check_keys(value, info, source, ['type'], ['if'])
257        check_if(value, info, source)
258        check_type(value['type'], info, source)
259
260
261def check_command(expr, info):
262    args = expr.get('data')
263    rets = expr.get('returns')
264    boxed = expr.get('boxed', False)
265
266    if boxed and args is None:
267        raise QAPISemError(info, "'boxed': true requires 'data'")
268    check_type(args, info, "'data'", allow_dict=not boxed)
269    check_type(rets, info, "'returns'", allow_array=True)
270
271
272def check_event(expr, info):
273    args = expr.get('data')
274    boxed = expr.get('boxed', False)
275
276    if boxed and args is None:
277        raise QAPISemError(info, "'boxed': true requires 'data'")
278    check_type(args, info, "'data'", allow_dict=not boxed)
279
280
281def check_exprs(exprs):
282    for expr_elem in exprs:
283        expr = expr_elem['expr']
284        info = expr_elem['info']
285        doc = expr_elem.get('doc')
286
287        if 'include' in expr:
288            continue
289
290        if 'enum' in expr:
291            meta = 'enum'
292        elif 'union' in expr:
293            meta = 'union'
294        elif 'alternate' in expr:
295            meta = 'alternate'
296        elif 'struct' in expr:
297            meta = 'struct'
298        elif 'command' in expr:
299            meta = 'command'
300        elif 'event' in expr:
301            meta = 'event'
302        else:
303            raise QAPISemError(info, "expression is missing metatype")
304
305        name = expr[meta]
306        check_name_is_str(name, info, "'%s'" % meta)
307        info.set_defn(meta, name)
308        check_defn_name_str(name, info, meta)
309
310        if doc:
311            if doc.symbol != name:
312                raise QAPISemError(
313                    info, "documentation comment is for '%s'" % doc.symbol)
314            doc.check_expr(expr)
315        elif info.pragma.doc_required:
316            raise QAPISemError(info,
317                               "documentation comment required")
318
319        if meta == 'enum':
320            check_keys(expr, info, meta,
321                       ['enum', 'data'], ['if', 'features', 'prefix'])
322            check_enum(expr, info)
323        elif meta == 'union':
324            check_keys(expr, info, meta,
325                       ['union', 'data'],
326                       ['base', 'discriminator', 'if', 'features'])
327            normalize_members(expr.get('base'))
328            normalize_members(expr['data'])
329            check_union(expr, info)
330        elif meta == 'alternate':
331            check_keys(expr, info, meta,
332                       ['alternate', 'data'], ['if', 'features'])
333            normalize_members(expr['data'])
334            check_alternate(expr, info)
335        elif meta == 'struct':
336            check_keys(expr, info, meta,
337                       ['struct', 'data'], ['base', 'if', 'features'])
338            normalize_members(expr['data'])
339            check_struct(expr, info)
340        elif meta == 'command':
341            check_keys(expr, info, meta,
342                       ['command'],
343                       ['data', 'returns', 'boxed', 'if', 'features',
344                        'gen', 'success-response', 'allow-oob',
345                        'allow-preconfig'])
346            normalize_members(expr.get('data'))
347            check_command(expr, info)
348        elif meta == 'event':
349            check_keys(expr, info, meta,
350                       ['event'], ['data', 'boxed', 'if', 'features'])
351            normalize_members(expr.get('data'))
352            check_event(expr, info)
353        else:
354            assert False, 'unexpected meta type'
355
356        check_if(expr, info, meta)
357        check_features(expr.get('features'), info)
358        check_flags(expr, info)
359
360    return exprs
361