src/backend/catalog/pg_proc.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_proc.c
   4  *        routines to support manipulation of the pg_proc relation
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.150 2008/03/25 22:42:42 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/heapam.h"
  18 #include "access/xact.h"
  19 #include "catalog/dependency.h"
  20 #include "catalog/indexing.h"
  21 #include "catalog/pg_language.h"
  22 #include "catalog/pg_namespace.h"
  23 #include "catalog/pg_proc.h"
  24 #include "catalog/pg_type.h"
  25 #include "executor/functions.h"
  26 #include "funcapi.h"
  27 #include "mb/pg_wchar.h"
  28 #include "miscadmin.h"
  29 #include "parser/parse_type.h"
  30 #include "tcop/pquery.h"
  31 #include "tcop/tcopprot.h"
  32 #include "utils/acl.h"
  33 #include "utils/builtins.h"
  34 #include "utils/lsyscache.h"
  35 #include "utils/syscache.h"
  36
  37
  38 Datum           fmgr_internal_validator(PG_FUNCTION_ARGS);
  39 Datum           fmgr_c_validator(PG_FUNCTION_ARGS);
  40 Datum           fmgr_sql_validator(PG_FUNCTION_ARGS);
  41
  42 static void sql_function_parse_error_callback(void *arg);
  43 static int match_prosrc_to_query(const char *prosrc, const char *queryText,
  44                                           int cursorpos);
  45 static bool match_prosrc_to_literal(const char *prosrc, const char *literal,
  46                                                 int cursorpos, int *newcursorpos);
  47
  48
  49 /* ----------------------------------------------------------------
  50  *              ProcedureCreate
  51  *
  52  * Note: allParameterTypes, parameterModes, parameterNames, and proconfig
  53  * are either arrays of the proper types or NULL.  We declare them Datum,
  54  * not "ArrayType *", to avoid importing array.h into pg_proc.h.
  55  * ----------------------------------------------------------------
  56  */
  57 Oid
  58 ProcedureCreate(const char *procedureName,
  59                                 Oid procNamespace,
  60                                 bool replace,
  61                                 bool returnsSet,
  62                                 Oid returnType,
  63                                 Oid languageObjectId,
  64                                 Oid languageValidator,
  65                                 const char *prosrc,
  66                                 const char *probin,
  67                                 bool isAgg,
  68                                 bool security_definer,
  69                                 bool isStrict,
  70                                 char volatility,
  71                                 oidvector *parameterTypes,
  72                                 Datum allParameterTypes,
  73                                 Datum parameterModes,
  74                                 Datum parameterNames,
  75                                 Datum proconfig,
  76                                 float4 procost,
  77                                 float4 prorows)
  78 {
  79         Oid                     retval;
  80         int                     parameterCount;
  81         int                     allParamCount;
  82         Oid                *allParams;
  83         bool            genericInParam = false;
  84         bool            genericOutParam = false;
  85         bool            internalInParam = false;
  86         bool            internalOutParam = false;
  87         Relation        rel;
  88         HeapTuple       tup;
  89         HeapTuple       oldtup;
  90         char            nulls[Natts_pg_proc];
  91         Datum           values[Natts_pg_proc];
  92         char            replaces[Natts_pg_proc];
  93         Oid                     relid;
  94         NameData        procname;
  95         TupleDesc       tupDesc;
  96         bool            is_update;
  97         ObjectAddress myself,
  98                                 referenced;
  99         int                     i;
 100
 101         /*
 102          * sanity checks
 103          */
 104         Assert(PointerIsValid(prosrc));
 105         Assert(PointerIsValid(probin));
 106
 107         parameterCount = parameterTypes->dim1;
 108         if (parameterCount < 0 || parameterCount > FUNC_MAX_ARGS)
 109                 ereport(ERROR,
 110                                 (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
 111                                  errmsg("functions cannot have more than %d arguments",
 112                                                 FUNC_MAX_ARGS)));
 113         /* note: the above is correct, we do NOT count output arguments */
 114
 115         if (allParameterTypes != PointerGetDatum(NULL))
 116         {
 117                 /*
 118                  * We expect the array to be a 1-D OID array; verify that. We don't
 119                  * need to use deconstruct_array() since the array data is just going
 120                  * to look like a C array of OID values.
 121                  */
 122                 ArrayType  *allParamArray = (ArrayType *) DatumGetPointer(allParameterTypes);
 123
 124                 allParamCount = ARR_DIMS(allParamArray)[0];
 125                 if (ARR_NDIM(allParamArray) != 1 ||
 126                         allParamCount <= 0 ||
 127                         ARR_HASNULL(allParamArray) ||
 128                         ARR_ELEMTYPE(allParamArray) != OIDOID)
 129                         elog(ERROR, "allParameterTypes is not a 1-D Oid array");
 130                 allParams = (Oid *) ARR_DATA_PTR(allParamArray);
 131                 Assert(allParamCount >= parameterCount);
 132                 /* we assume caller got the contents right */
 133         }
 134         else
 135         {
 136                 allParamCount = parameterCount;
 137                 allParams = parameterTypes->values;
 138         }
 139
 140         /*
 141          * Do not allow polymorphic return type unless at least one input argument
 142          * is polymorphic.      Also, do not allow return type INTERNAL unless at
 143          * least one input argument is INTERNAL.
 144          */
 145         for (i = 0; i < parameterCount; i++)
 146         {
 147                 switch (parameterTypes->values[i])
 148                 {
 149                         case ANYARRAYOID:
 150                         case ANYELEMENTOID:
 151                         case ANYNONARRAYOID:
 152                         case ANYENUMOID:
 153                                 genericInParam = true;
 154                                 break;
 155                         case INTERNALOID:
 156                                 internalInParam = true;
 157                                 break;
 158                 }
 159         }
 160
 161         if (allParameterTypes != PointerGetDatum(NULL))
 162         {
 163                 for (i = 0; i < allParamCount; i++)
 164                 {
 165                         /*
 166                          * We don't bother to distinguish input and output params here, so
 167                          * if there is, say, just an input INTERNAL param then we will
 168                          * still set internalOutParam.  This is OK since we don't really
 169                          * care.
 170                          */
 171                         switch (allParams[i])
 172                         {
 173                                 case ANYARRAYOID:
 174                                 case ANYELEMENTOID:
 175                                 case ANYNONARRAYOID:
 176                                 case ANYENUMOID:
 177                                         genericOutParam = true;
 178                                         break;
 179                                 case INTERNALOID:
 180                                         internalOutParam = true;
 181                                         break;
 182                         }
 183                 }
 184         }
 185
 186         if ((IsPolymorphicType(returnType) || genericOutParam)
 187                 && !genericInParam)
 188                 ereport(ERROR,
 189                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 190                                  errmsg("cannot determine result data type"),
 191                                  errdetail("A function returning a polymorphic type must have at least one polymorphic argument.")));
 192
 193         if ((returnType == INTERNALOID || internalOutParam) && !internalInParam)
 194                 ereport(ERROR,
 195                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 196                                  errmsg("unsafe use of pseudo-type \"internal\""),
 197                                  errdetail("A function returning \"internal\" must have at least one \"internal\" argument.")));
 198
 199         /*
 200          * don't allow functions of complex types that have the same name as
 201          * existing attributes of the type
 202          */
 203         if (parameterCount == 1 &&
 204                 OidIsValid(parameterTypes->values[0]) &&
 205                 (relid = typeidTypeRelid(parameterTypes->values[0])) != InvalidOid &&
 206                 get_attnum(relid, procedureName) != InvalidAttrNumber)
 207                 ereport(ERROR,
 208                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 209                                  errmsg("\"%s\" is already an attribute of type %s",
 210                                                 procedureName,
 211                                                 format_type_be(parameterTypes->values[0]))));
 212
 213         /*
 214          * All seems OK; prepare the data to be inserted into pg_proc.
 215          */
 216
 217         for (i = 0; i < Natts_pg_proc; ++i)
 218         {
 219                 nulls[i] = ' ';
 220                 values[i] = (Datum) 0;
 221                 replaces[i] = 'r';
 222         }
 223
 224         namestrcpy(&procname, procedureName);
 225         values[Anum_pg_proc_proname - 1] = NameGetDatum(&procname);
 226         values[Anum_pg_proc_pronamespace - 1] = ObjectIdGetDatum(procNamespace);
 227         values[Anum_pg_proc_proowner - 1] = ObjectIdGetDatum(GetUserId());
 228         values[Anum_pg_proc_prolang - 1] = ObjectIdGetDatum(languageObjectId);
 229         values[Anum_pg_proc_procost - 1] = Float4GetDatum(procost);
 230         values[Anum_pg_proc_prorows - 1] = Float4GetDatum(prorows);
 231         values[Anum_pg_proc_proisagg - 1] = BoolGetDatum(isAgg);
 232         values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
 233         values[Anum_pg_proc_proisstrict - 1] = BoolGetDatum(isStrict);
 234         values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
 235         values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
 236         values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
 237         values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
 238         values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(parameterTypes);
 239         if (allParameterTypes != PointerGetDatum(NULL))
 240                 values[Anum_pg_proc_proallargtypes - 1] = allParameterTypes;
 241         else
 242                 nulls[Anum_pg_proc_proallargtypes - 1] = 'n';
 243         if (parameterModes != PointerGetDatum(NULL))
 244                 values[Anum_pg_proc_proargmodes - 1] = parameterModes;
 245         else
 246                 nulls[Anum_pg_proc_proargmodes - 1] = 'n';
 247         if (parameterNames != PointerGetDatum(NULL))
 248                 values[Anum_pg_proc_proargnames - 1] = parameterNames;
 249         else
 250                 nulls[Anum_pg_proc_proargnames - 1] = 'n';
 251         values[Anum_pg_proc_prosrc - 1] = CStringGetTextDatum(prosrc);
 252         values[Anum_pg_proc_probin - 1] = CStringGetTextDatum(probin);
 253         if (proconfig != PointerGetDatum(NULL))
 254                 values[Anum_pg_proc_proconfig - 1] = proconfig;
 255         else
 256                 nulls[Anum_pg_proc_proconfig - 1] = 'n';
 257         /* start out with empty permissions */
 258         nulls[Anum_pg_proc_proacl - 1] = 'n';
 259
 260         rel = heap_open(ProcedureRelationId, RowExclusiveLock);
 261         tupDesc = RelationGetDescr(rel);
 262
 263         /* Check for pre-existing definition */
 264         oldtup = SearchSysCache(PROCNAMEARGSNSP,
 265                                                         PointerGetDatum(procedureName),
 266                                                         PointerGetDatum(parameterTypes),
 267                                                         ObjectIdGetDatum(procNamespace),
 268                                                         0);
 269
 270         if (HeapTupleIsValid(oldtup))
 271         {
 272                 /* There is one; okay to replace it? */
 273                 Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);
 274
 275                 if (!replace)
 276                         ereport(ERROR,
 277                                         (errcode(ERRCODE_DUPLICATE_FUNCTION),
 278                         errmsg("function \"%s\" already exists with same argument types",
 279                                    procedureName)));
 280                 if (!pg_proc_ownercheck(HeapTupleGetOid(oldtup), GetUserId()))
 281                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
 282                                                    procedureName);
 283
 284                 /*
 285                  * Not okay to change the return type of the existing proc, since
 286                  * existing rules, views, etc may depend on the return type.
 287                  */
 288                 if (returnType != oldproc->prorettype ||
 289                         returnsSet != oldproc->proretset)
 290                         ereport(ERROR,
 291                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 292                                          errmsg("cannot change return type of existing function"),
 293                                          errhint("Use DROP FUNCTION first.")));
 294
 295                 /*
 296                  * If it returns RECORD, check for possible change of record type
 297                  * implied by OUT parameters
 298                  */
 299                 if (returnType == RECORDOID)
 300                 {
 301                         TupleDesc       olddesc;
 302                         TupleDesc       newdesc;
 303
 304                         olddesc = build_function_result_tupdesc_t(oldtup);
 305                         newdesc = build_function_result_tupdesc_d(allParameterTypes,
 306                                                                                                           parameterModes,
 307                                                                                                           parameterNames);
 308                         if (olddesc == NULL && newdesc == NULL)
 309                                  /* ok, both are runtime-defined RECORDs */ ;
 310                         else if (olddesc == NULL || newdesc == NULL ||
 311                                          !equalTupleDescs(olddesc, newdesc))
 312                                 ereport(ERROR,
 313                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 314                                         errmsg("cannot change return type of existing function"),
 315                                 errdetail("Row type defined by OUT parameters is different."),
 316                                                  errhint("Use DROP FUNCTION first.")));
 317                 }
 318
 319                 /* Can't change aggregate status, either */
 320                 if (oldproc->proisagg != isAgg)
 321                 {
 322                         if (oldproc->proisagg)
 323                                 ereport(ERROR,
 324                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 325                                                  errmsg("function \"%s\" is an aggregate",
 326                                                                 procedureName)));
 327                         else
 328                                 ereport(ERROR,
 329                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 330                                                  errmsg("function \"%s\" is not an aggregate",
 331                                                                 procedureName)));
 332                 }
 333
 334                 /* do not change existing ownership or permissions, either */
 335                 replaces[Anum_pg_proc_proowner - 1] = ' ';
 336                 replaces[Anum_pg_proc_proacl - 1] = ' ';
 337
 338                 /* Okay, do it... */
 339                 tup = heap_modifytuple(oldtup, tupDesc, values, nulls, replaces);
 340                 simple_heap_update(rel, &tup->t_self, tup);
 341
 342                 ReleaseSysCache(oldtup);
 343                 is_update = true;
 344         }
 345         else
 346         {
 347                 /* Creating a new procedure */
 348                 tup = heap_formtuple(tupDesc, values, nulls);
 349                 simple_heap_insert(rel, tup);
 350                 is_update = false;
 351         }
 352
 353         /* Need to update indexes for either the insert or update case */
 354         CatalogUpdateIndexes(rel, tup);
 355
 356         retval = HeapTupleGetOid(tup);
 357
 358         /*
 359          * Create dependencies for the new function.  If we are updating an
 360          * existing function, first delete any existing pg_depend entries.
 361          */
 362         if (is_update)
 363         {
 364                 deleteDependencyRecordsFor(ProcedureRelationId, retval);
 365                 deleteSharedDependencyRecordsFor(ProcedureRelationId, retval);
 366         }
 367
 368         myself.classId = ProcedureRelationId;
 369         myself.objectId = retval;
 370         myself.objectSubId = 0;
 371
 372         /* dependency on namespace */
 373         referenced.classId = NamespaceRelationId;
 374         referenced.objectId = procNamespace;
 375         referenced.objectSubId = 0;
 376         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 377
 378         /* dependency on implementation language */
 379         referenced.classId = LanguageRelationId;
 380         referenced.objectId = languageObjectId;
 381         referenced.objectSubId = 0;
 382         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 383
 384         /* dependency on return type */
 385         referenced.classId = TypeRelationId;
 386         referenced.objectId = returnType;
 387         referenced.objectSubId = 0;
 388         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 389
 390         /* dependency on parameter types */
 391         for (i = 0; i < allParamCount; i++)
 392         {
 393                 referenced.classId = TypeRelationId;
 394                 referenced.objectId = allParams[i];
 395                 referenced.objectSubId = 0;
 396                 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 397         }
 398
 399         /* dependency on owner */
 400         recordDependencyOnOwner(ProcedureRelationId, retval, GetUserId());
 401
 402         heap_freetuple(tup);
 403
 404         heap_close(rel, RowExclusiveLock);
 405
 406         /* Verify function body */
 407         if (OidIsValid(languageValidator))
 408         {
 409                 /* Advance command counter so new tuple can be seen by validator */
 410                 CommandCounterIncrement();
 411                 OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
 412         }
 413
 414         return retval;
 415 }
 416
 417
 418
 419 /*
 420  * Validator for internal functions
 421  *
 422  * Check that the given internal function name (the "prosrc" value) is
 423  * a known builtin function.
 424  */
 425 Datum
 426 fmgr_internal_validator(PG_FUNCTION_ARGS)
 427 {
 428         Oid                     funcoid = PG_GETARG_OID(0);
 429         HeapTuple       tuple;
 430         Form_pg_proc proc;
 431         bool            isnull;
 432         Datum           tmp;
 433         char       *prosrc;
 434
 435         /*
 436          * We do not honor check_function_bodies since it's unlikely the function
 437          * name will be found later if it isn't there now.
 438          */
 439
 440         tuple = SearchSysCache(PROCOID,
 441                                                    ObjectIdGetDatum(funcoid),
 442                                                    0, 0, 0);
 443         if (!HeapTupleIsValid(tuple))
 444                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 445         proc = (Form_pg_proc) GETSTRUCT(tuple);
 446
 447         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 448         if (isnull)
 449                 elog(ERROR, "null prosrc");
 450         prosrc = TextDatumGetCString(tmp);
 451
 452         if (fmgr_internal_function(prosrc) == InvalidOid)
 453                 ereport(ERROR,
 454                                 (errcode(ERRCODE_UNDEFINED_FUNCTION),
 455                                  errmsg("there is no built-in function named \"%s\"",
 456                                                 prosrc)));
 457
 458         ReleaseSysCache(tuple);
 459
 460         PG_RETURN_VOID();
 461 }
 462
 463
 464
 465 /*
 466  * Validator for C language functions
 467  *
 468  * Make sure that the library file exists, is loadable, and contains
 469  * the specified link symbol. Also check for a valid function
 470  * information record.
 471  */
 472 Datum
 473 fmgr_c_validator(PG_FUNCTION_ARGS)
 474 {
 475         Oid                     funcoid = PG_GETARG_OID(0);
 476         void       *libraryhandle;
 477         HeapTuple       tuple;
 478         Form_pg_proc proc;
 479         bool            isnull;
 480         Datum           tmp;
 481         char       *prosrc;
 482         char       *probin;
 483
 484         /*
 485          * It'd be most consistent to skip the check if !check_function_bodies,
 486          * but the purpose of that switch is to be helpful for pg_dump loading,
 487          * and for pg_dump loading it's much better if we *do* check.
 488          */
 489
 490         tuple = SearchSysCache(PROCOID,
 491                                                    ObjectIdGetDatum(funcoid),
 492                                                    0, 0, 0);
 493         if (!HeapTupleIsValid(tuple))
 494                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 495         proc = (Form_pg_proc) GETSTRUCT(tuple);
 496
 497         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 498         if (isnull)
 499                 elog(ERROR, "null prosrc");
 500         prosrc = TextDatumGetCString(tmp);
 501
 502         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_probin, &isnull);
 503         if (isnull)
 504                 elog(ERROR, "null probin");
 505         probin = TextDatumGetCString(tmp);
 506
 507         (void) load_external_function(probin, prosrc, true, &libraryhandle);
 508         (void) fetch_finfo_record(libraryhandle, prosrc);
 509
 510         ReleaseSysCache(tuple);
 511
 512         PG_RETURN_VOID();
 513 }
 514
 515
 516 /*
 517  * Validator for SQL language functions
 518  *
 519  * Parse it here in order to be sure that it contains no syntax errors.
 520  */
 521 Datum
 522 fmgr_sql_validator(PG_FUNCTION_ARGS)
 523 {
 524         Oid                     funcoid = PG_GETARG_OID(0);
 525         HeapTuple       tuple;
 526         Form_pg_proc proc;
 527         List       *querytree_list;
 528         bool            isnull;
 529         Datum           tmp;
 530         char       *prosrc;
 531         ErrorContextCallback sqlerrcontext;
 532         bool            haspolyarg;
 533         int                     i;
 534
 535         tuple = SearchSysCache(PROCOID,
 536                                                    ObjectIdGetDatum(funcoid),
 537                                                    0, 0, 0);
 538         if (!HeapTupleIsValid(tuple))
 539                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 540         proc = (Form_pg_proc) GETSTRUCT(tuple);
 541
 542         /* Disallow pseudotype result */
 543         /* except for RECORD, VOID, or polymorphic */
 544         if (get_typtype(proc->prorettype) == TYPTYPE_PSEUDO &&
 545                 proc->prorettype != RECORDOID &&
 546                 proc->prorettype != VOIDOID &&
 547                 !IsPolymorphicType(proc->prorettype))
 548                 ereport(ERROR,
 549                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 550                                  errmsg("SQL functions cannot return type %s",
 551                                                 format_type_be(proc->prorettype))));
 552
 553         /* Disallow pseudotypes in arguments */
 554         /* except for polymorphic */
 555         haspolyarg = false;
 556         for (i = 0; i < proc->pronargs; i++)
 557         {
 558                 if (get_typtype(proc->proargtypes.values[i]) == TYPTYPE_PSEUDO)
 559                 {
 560                         if (IsPolymorphicType(proc->proargtypes.values[i]))
 561                                 haspolyarg = true;
 562                         else
 563                                 ereport(ERROR,
 564                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 565                                          errmsg("SQL functions cannot have arguments of type %s",
 566                                                         format_type_be(proc->proargtypes.values[i]))));
 567                 }
 568         }
 569
 570         /* Postpone body checks if !check_function_bodies */
 571         if (check_function_bodies)
 572         {
 573                 tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 574                 if (isnull)
 575                         elog(ERROR, "null prosrc");
 576
 577                 prosrc = TextDatumGetCString(tmp);
 578
 579                 /*
 580                  * Setup error traceback support for ereport().
 581                  */
 582                 sqlerrcontext.callback = sql_function_parse_error_callback;
 583                 sqlerrcontext.arg = tuple;
 584                 sqlerrcontext.previous = error_context_stack;
 585                 error_context_stack = &sqlerrcontext;
 586
 587                 /*
 588                  * We can't do full prechecking of the function definition if there
 589                  * are any polymorphic input types, because actual datatypes of
 590                  * expression results will be unresolvable.  The check will be done at
 591                  * runtime instead.
 592                  *
 593                  * We can run the text through the raw parser though; this will at
 594                  * least catch silly syntactic errors.
 595                  */
 596                 if (!haspolyarg)
 597                 {
 598                         querytree_list = pg_parse_and_rewrite(prosrc,
 599                                                                                                   proc->proargtypes.values,
 600                                                                                                   proc->pronargs);
 601                         (void) check_sql_fn_retval(funcoid, proc->prorettype,
 602                                                                            querytree_list,
 603                                                                            false, NULL);
 604                 }
 605                 else
 606                         querytree_list = pg_parse_query(prosrc);
 607
 608                 error_context_stack = sqlerrcontext.previous;
 609         }
 610
 611         ReleaseSysCache(tuple);
 612
 613         PG_RETURN_VOID();
 614 }
 615
 616 /*
 617  * Error context callback for handling errors in SQL function definitions
 618  */
 619 static void
 620 sql_function_parse_error_callback(void *arg)
 621 {
 622         HeapTuple       tuple = (HeapTuple) arg;
 623         Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tuple);
 624         bool            isnull;
 625         Datum           tmp;
 626         char       *prosrc;
 627
 628         /* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
 629         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 630         if (isnull)
 631                 elog(ERROR, "null prosrc");
 632         prosrc = TextDatumGetCString(tmp);
 633
 634         if (!function_parse_error_transpose(prosrc))
 635         {
 636                 /* If it's not a syntax error, push info onto context stack */
 637                 errcontext("SQL function \"%s\"", NameStr(proc->proname));
 638         }
 639
 640         pfree(prosrc);
 641 }
 642
 643 /*
 644  * Adjust a syntax error occurring inside the function body of a CREATE
 645  * FUNCTION command.  This can be used by any function validator, not only
 646  * for SQL-language functions.  It is assumed that the syntax error position
 647  * is initially relative to the function body string (as passed in).  If
 648  * possible, we adjust the position to reference the original CREATE command;
 649  * if we can't manage that, we set up an "internal query" syntax error instead.
 650  *
 651  * Returns true if a syntax error was processed, false if not.
 652  */
 653 bool
 654 function_parse_error_transpose(const char *prosrc)
 655 {
 656         int                     origerrposition;
 657         int                     newerrposition;
 658         const char *queryText;
 659
 660         /*
 661          * Nothing to do unless we are dealing with a syntax error that has a
 662          * cursor position.
 663          *
 664          * Some PLs may prefer to report the error position as an internal error
 665          * to begin with, so check that too.
 666          */
 667         origerrposition = geterrposition();
 668         if (origerrposition <= 0)
 669         {
 670                 origerrposition = getinternalerrposition();
 671                 if (origerrposition <= 0)
 672                         return false;
 673         }
 674
 675         /* We can get the original query text from the active portal (hack...) */
 676         Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
 677         queryText = ActivePortal->sourceText;
 678
 679         /* Try to locate the prosrc in the original text */
 680         newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);
 681
 682         if (newerrposition > 0)
 683         {
 684                 /* Successful, so fix error position to reference original query */
 685                 errposition(newerrposition);
 686                 /* Get rid of any report of the error as an "internal query" */
 687                 internalerrposition(0);
 688                 internalerrquery(NULL);
 689         }
 690         else
 691         {
 692                 /*
 693                  * If unsuccessful, convert the position to an internal position
 694                  * marker and give the function text as the internal query.
 695                  */
 696                 errposition(0);
 697                 internalerrposition(origerrposition);
 698                 internalerrquery(prosrc);
 699         }
 700
 701         return true;
 702 }
 703
 704 /*
 705  * Try to locate the string literal containing the function body in the
 706  * given text of the CREATE FUNCTION command.  If successful, return the
 707  * character (not byte) index within the command corresponding to the
 708  * given character index within the literal.  If not successful, return 0.
 709  */
 710 static int
 711 match_prosrc_to_query(const char *prosrc, const char *queryText,
 712                                           int cursorpos)
 713 {
 714         /*
 715          * Rather than fully parsing the CREATE FUNCTION command, we just scan the
 716          * command looking for $prosrc$ or 'prosrc'.  This could be fooled (though
 717          * not in any very probable scenarios), so fail if we find more than one
 718          * match.
 719          */
 720         int                     prosrclen = strlen(prosrc);
 721         int                     querylen = strlen(queryText);
 722         int                     matchpos = 0;
 723         int                     curpos;
 724         int                     newcursorpos;
 725
 726         for (curpos = 0; curpos < querylen - prosrclen; curpos++)
 727         {
 728                 if (queryText[curpos] == '$' &&
 729                         strncmp(prosrc, &queryText[curpos + 1], prosrclen) == 0 &&
 730                         queryText[curpos + 1 + prosrclen] == '$')
 731                 {
 732                         /*
 733                          * Found a $foo$ match.  Since there are no embedded quoting
 734                          * characters in a dollar-quoted literal, we don't have to do any
 735                          * fancy arithmetic; just offset by the starting position.
 736                          */
 737                         if (matchpos)
 738                                 return 0;               /* multiple matches, fail */
 739                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 740                                 + cursorpos;
 741                 }
 742                 else if (queryText[curpos] == '\'' &&
 743                                  match_prosrc_to_literal(prosrc, &queryText[curpos + 1],
 744                                                                                  cursorpos, &newcursorpos))
 745                 {
 746                         /*
 747                          * Found a 'foo' match.  match_prosrc_to_literal() has adjusted
 748                          * for any quotes or backslashes embedded in the literal.
 749                          */
 750                         if (matchpos)
 751                                 return 0;               /* multiple matches, fail */
 752                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 753                                 + newcursorpos;
 754                 }
 755         }
 756
 757         return matchpos;
 758 }
 759
 760 /*
 761  * Try to match the given source text to a single-quoted literal.
 762  * If successful, adjust newcursorpos to correspond to the character
 763  * (not byte) index corresponding to cursorpos in the source text.
 764  *
 765  * At entry, literal points just past a ' character.  We must check for the
 766  * trailing quote.
 767  */
 768 static bool
 769 match_prosrc_to_literal(const char *prosrc, const char *literal,
 770                                                 int cursorpos, int *newcursorpos)
 771 {
 772         int                     newcp = cursorpos;
 773         int                     chlen;
 774
 775         /*
 776          * This implementation handles backslashes and doubled quotes in the
 777          * string literal.      It does not handle the SQL syntax for literals
 778          * continued across line boundaries.
 779          *
 780          * We do the comparison a character at a time, not a byte at a time, so
 781          * that we can do the correct cursorpos math.
 782          */
 783         while (*prosrc)
 784         {
 785                 cursorpos--;                    /* characters left before cursor */
 786
 787                 /*
 788                  * Check for backslashes and doubled quotes in the literal; adjust
 789                  * newcp when one is found before the cursor.
 790                  */
 791                 if (*literal == '\\')
 792                 {
 793                         literal++;
 794                         if (cursorpos > 0)
 795                                 newcp++;
 796                 }
 797                 else if (*literal == '\'')
 798                 {
 799                         if (literal[1] != '\'')
 800                                 goto fail;
 801                         literal++;
 802                         if (cursorpos > 0)
 803                                 newcp++;
 804                 }
 805                 chlen = pg_mblen(prosrc);
 806                 if (strncmp(prosrc, literal, chlen) != 0)
 807                         goto fail;
 808                 prosrc += chlen;
 809                 literal += chlen;
 810         }
 811
 812         if (*literal == '\'' && literal[1] != '\'')
 813         {
 814                 /* success */
 815                 *newcursorpos = newcp;
 816                 return true;
 817         }
 818
 819 fail:
 820         /* Must set *newcursorpos to suppress compiler warning */
 821         *newcursorpos = newcp;
 822         return false;
 823 }