xref: /qemu/scripts/qapi/expr.py (revision 922d42bb) 
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
17from collections import OrderedDict
18import re
19
20from .common import c_name
21from .error import QAPISemError
22
23
24# Names must be letters, numbers, -, and _.  They must start with letter,
25# except for downstream extensions which must start with __RFQDN_.
26# Dots are only valid in the downstream extension prefix.
27valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
28                        '[a-zA-Z][a-zA-Z0-9_-]*$')
29
30
31def check_name_is_str(name, info, source):
32    if not isinstance(name, str):
33        raise QAPISemError(info, "%s requires a string name" % source)
34
35
36def check_name_str(name, info, source,
37                   allow_optional=False, enum_member=False,
38                   permit_upper=False):
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', 'coroutine']:
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    if 'allow-oob' in expr and 'coroutine' in expr:
97        # This is not necessarily a fundamental incompatibility, but
98        # we don't have a use case and the desired semantics isn't
99        # obvious.  The simplest solution is to forbid it until we get
100        # a use case for it.
101        raise QAPISemError(info, "flags 'allow-oob' and 'coroutine' "
102                                 "are incompatible")
103
104
105def check_if(expr, info, source):
106
107    def check_if_str(ifcond, info):
108        if not isinstance(ifcond, str):
109            raise QAPISemError(
110                info,
111                "'if' condition of %s must be a string or a list of strings"
112                % source)
113        if ifcond.strip() == '':
114            raise QAPISemError(
115                info,
116                "'if' condition '%s' of %s makes no sense"
117                % (ifcond, source))
118
119    ifcond = expr.get('if')
120    if ifcond is None:
121        return
122    if isinstance(ifcond, list):
123        if ifcond == []:
124            raise QAPISemError(
125                info, "'if' condition [] of %s is useless" % source)
126        for elt in ifcond:
127            check_if_str(elt, info)
128    else:
129        check_if_str(ifcond, info)
130        expr['if'] = [ifcond]
131
132
133def normalize_members(members):
134    if isinstance(members, OrderedDict):
135        for key, arg in members.items():
136            if isinstance(arg, dict):
137                continue
138            members[key] = {'type': arg}
139
140
141def check_type(value, info, source,
142               allow_array=False, allow_dict=False):
143    if value is None:
144        return
145
146    # Array type
147    if isinstance(value, list):
148        if not allow_array:
149            raise QAPISemError(info, "%s cannot be an array" % source)
150        if len(value) != 1 or not isinstance(value[0], str):
151            raise QAPISemError(info,
152                               "%s: array type must contain single type name" %
153                               source)
154        return
155
156    # Type name
157    if isinstance(value, str):
158        return
159
160    # Anonymous type
161
162    if not allow_dict:
163        raise QAPISemError(info, "%s should be a type name" % source)
164
165    if not isinstance(value, OrderedDict):
166        raise QAPISemError(info,
167                           "%s should be an object or type name" % source)
168
169    permit_upper = allow_dict in info.pragma.name_case_whitelist
170
171    # value is a dictionary, check that each member is okay
172    for (key, arg) in value.items():
173        key_source = "%s member '%s'" % (source, key)
174        check_name_str(key, info, key_source,
175                       allow_optional=True, permit_upper=permit_upper)
176        if c_name(key, False) == 'u' or c_name(key, False).startswith('has_'):
177            raise QAPISemError(info, "%s uses reserved name" % key_source)
178        check_keys(arg, info, key_source, ['type'], ['if', 'features'])
179        check_if(arg, info, key_source)
180        check_features(arg.get('features'), info)
181        check_type(arg['type'], info, key_source, allow_array=True)
182
183
184def check_features(features, info):
185    if features is None:
186        return
187    if not isinstance(features, list):
188        raise QAPISemError(info, "'features' must be an array")
189    features[:] = [f if isinstance(f, dict) else {'name': f}
190                   for f in features]
191    for f in features:
192        source = "'features' member"
193        assert isinstance(f, dict)
194        check_keys(f, info, source, ['name'], ['if'])
195        check_name_is_str(f['name'], info, source)
196        source = "%s '%s'" % (source, f['name'])
197        check_name_str(f['name'], info, source)
198        check_if(f, info, source)
199
200
201def check_enum(expr, info):
202    name = expr['enum']
203    members = expr['data']
204    prefix = expr.get('prefix')
205
206    if not isinstance(members, list):
207        raise QAPISemError(info, "'data' must be an array")
208    if prefix is not None and not isinstance(prefix, str):
209        raise QAPISemError(info, "'prefix' must be a string")
210
211    permit_upper = name in info.pragma.name_case_whitelist
212
213    members[:] = [m if isinstance(m, dict) else {'name': m}
214                  for m in members]
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
232
233def check_union(expr, info):
234    name = expr['union']
235    base = expr.get('base')
236    discriminator = expr.get('discriminator')
237    members = expr['data']
238
239    if discriminator is None:   # simple union
240        if base is not None:
241            raise QAPISemError(info, "'base' requires 'discriminator'")
242    else:                       # flat union
243        check_type(base, info, "'base'", allow_dict=name)
244        if not base:
245            raise QAPISemError(info, "'discriminator' requires 'base'")
246        check_name_is_str(discriminator, info, "'discriminator'")
247
248    for (key, value) in members.items():
249        source = "'data' member '%s'" % key
250        check_name_str(key, info, source)
251        check_keys(value, info, source, ['type'], ['if'])
252        check_if(value, info, source)
253        check_type(value['type'], info, source, allow_array=not base)
254
255
256def check_alternate(expr, info):
257    members = expr['data']
258
259    if not members:
260        raise QAPISemError(info, "'data' must not be empty")
261    for (key, value) in members.items():
262        source = "'data' member '%s'" % key
263        check_name_str(key, info, source)
264        check_keys(value, info, source, ['type'], ['if'])
265        check_if(value, info, source)
266        check_type(value['type'], info, source)
267
268
269def check_command(expr, info):
270    args = expr.get('data')
271    rets = expr.get('returns')
272    boxed = expr.get('boxed', False)
273
274    if boxed and args is None:
275        raise QAPISemError(info, "'boxed': true requires 'data'")
276    check_type(args, info, "'data'", allow_dict=not boxed)
277    check_type(rets, info, "'returns'", allow_array=True)
278
279
280def check_event(expr, info):
281    args = expr.get('data')
282    boxed = expr.get('boxed', False)
283
284    if boxed and args is None:
285        raise QAPISemError(info, "'boxed': true requires 'data'")
286    check_type(args, info, "'data'", allow_dict=not boxed)
287
288
289def check_exprs(exprs):
290    for expr_elem in exprs:
291        expr = expr_elem['expr']
292        info = expr_elem['info']
293        doc = expr_elem.get('doc')
294
295        if 'include' in expr:
296            continue
297
298        if 'enum' in expr:
299            meta = 'enum'
300        elif 'union' in expr:
301            meta = 'union'
302        elif 'alternate' in expr:
303            meta = 'alternate'
304        elif 'struct' in expr:
305            meta = 'struct'
306        elif 'command' in expr:
307            meta = 'command'
308        elif 'event' in expr:
309            meta = 'event'
310        else:
311            raise QAPISemError(info, "expression is missing metatype")
312
313        name = expr[meta]
314        check_name_is_str(name, info, "'%s'" % meta)
315        info.set_defn(meta, name)
316        check_defn_name_str(name, info, meta)
317
318        if doc:
319            if doc.symbol != name:
320                raise QAPISemError(
321                    info, "documentation comment is for '%s'" % doc.symbol)
322            doc.check_expr(expr)
323        elif info.pragma.doc_required:
324            raise QAPISemError(info,
325                               "documentation comment required")
326
327        if meta == 'enum':
328            check_keys(expr, info, meta,
329                       ['enum', 'data'], ['if', 'features', 'prefix'])
330            check_enum(expr, info)
331        elif meta == 'union':
332            check_keys(expr, info, meta,
333                       ['union', 'data'],
334                       ['base', 'discriminator', 'if', 'features'])
335            normalize_members(expr.get('base'))
336            normalize_members(expr['data'])
337            check_union(expr, info)
338        elif meta == 'alternate':
339            check_keys(expr, info, meta,
340                       ['alternate', 'data'], ['if', 'features'])
341            normalize_members(expr['data'])
342            check_alternate(expr, info)
343        elif meta == 'struct':
344            check_keys(expr, info, meta,
345                       ['struct', 'data'], ['base', 'if', 'features'])
346            normalize_members(expr['data'])
347            check_struct(expr, info)
348        elif meta == 'command':
349            check_keys(expr, info, meta,
350                       ['command'],
351                       ['data', 'returns', 'boxed', 'if', 'features',
352                        'gen', 'success-response', 'allow-oob',
353                        'allow-preconfig', 'coroutine'])
354            normalize_members(expr.get('data'))
355            check_command(expr, info)
356        elif meta == 'event':
357            check_keys(expr, info, meta,
358                       ['event'], ['data', 'boxed', 'if', 'features'])
359            normalize_members(expr.get('data'))
360            check_event(expr, info)
361        else:
362            assert False, 'unexpected meta type'
363
364        check_if(expr, info, meta)
365        check_features(expr.get('features'), info)
366        check_flags(expr, info)
367
368    return exprs
369