scripts/qapi/expr.py

   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
  17 import re
  18 from collections import OrderedDict
  19 from qapi.common import c_name
  20 from 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.
  26 valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
  27                         '[a-zA-Z][a-zA-Z0-9_-]*$')
  28
  29
  30 def 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
  35 def 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
  58 def 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
  65 def 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
  87 def 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
  98 def 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
 126 def 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
 134 def 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
 176 def 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
 182 def 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
 197 def 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
 203 def 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
 225 def 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
 234 def 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
 257 def 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
 270 def 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
 282 def 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
 291 def 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