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