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) 1996-2005, 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 1.136 2005/11/17 22:14:51 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/heapam.h"
  18 #include "catalog/dependency.h"
  19 #include "catalog/indexing.h"
  20 #include "catalog/pg_language.h"
  21 #include "catalog/pg_namespace.h"
  22 #include "catalog/pg_proc.h"
  23 #include "catalog/pg_type.h"
  24 #include "executor/functions.h"
  25 #include "funcapi.h"
  26 #include "miscadmin.h"
  27 #include "mb/pg_wchar.h"
  28 #include "parser/parse_type.h"
  29 #include "tcop/pquery.h"
  30 #include "tcop/tcopprot.h"
  31 #include "utils/acl.h"
  32 #include "utils/builtins.h"
  33 #include "utils/lsyscache.h"
  34 #include "utils/syscache.h"
  35
  36
  37 /* GUC parameter */
  38 bool            check_function_bodies = true;
  39
  40
  41 Datum           fmgr_internal_validator(PG_FUNCTION_ARGS);
  42 Datum           fmgr_c_validator(PG_FUNCTION_ARGS);
  43 Datum           fmgr_sql_validator(PG_FUNCTION_ARGS);
  44
  45 static void sql_function_parse_error_callback(void *arg);
  46 static int match_prosrc_to_query(const char *prosrc, const char *queryText,
  47                                           int cursorpos);
  48 static bool match_prosrc_to_literal(const char *prosrc, const char *literal,
  49                                                 int cursorpos, int *newcursorpos);
  50
  51
  52 /* ----------------------------------------------------------------
  53  *              ProcedureCreate
  54  *
  55  * Note: allParameterTypes, parameterModes, parameterNames are either arrays
  56  * of the proper types or NULL.  We declare them Datum, not "ArrayType *",
  57  * to avoid importing array.h into pg_proc.h.
  58  * ----------------------------------------------------------------
  59  */
  60 Oid
  61 ProcedureCreate(const char *procedureName,
  62                                 Oid procNamespace,
  63                                 bool replace,
  64                                 bool returnsSet,
  65                                 Oid returnType,
  66                                 Oid languageObjectId,
  67                                 Oid languageValidator,
  68                                 const char *prosrc,
  69                                 const char *probin,
  70                                 bool isAgg,
  71                                 bool security_definer,
  72                                 bool isStrict,
  73                                 char volatility,
  74                                 oidvector *parameterTypes,
  75                                 Datum allParameterTypes,
  76                                 Datum parameterModes,
  77                                 Datum parameterNames)
  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 return type ANYARRAY or ANYELEMENT unless at least one
 142          * input argument is ANYARRAY or ANYELEMENT.  Also, do not allow return
 143          * type INTERNAL unless at 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                                 genericInParam = true;
 152                                 break;
 153                         case INTERNALOID:
 154                                 internalInParam = true;
 155                                 break;
 156                 }
 157         }
 158
 159         if (allParameterTypes != PointerGetDatum(NULL))
 160         {
 161                 for (i = 0; i < allParamCount; i++)
 162                 {
 163                         /*
 164                          * We don't bother to distinguish input and output params here, so
 165                          * if there is, say, just an input INTERNAL param then we will
 166                          * still set internalOutParam.  This is OK since we don't really
 167                          * care.
 168                          */
 169                         switch (allParams[i])
 170                         {
 171                                 case ANYARRAYOID:
 172                                 case ANYELEMENTOID:
 173                                         genericOutParam = true;
 174                                         break;
 175                                 case INTERNALOID:
 176                                         internalOutParam = true;
 177                                         break;
 178                         }
 179                 }
 180         }
 181
 182         if ((returnType == ANYARRAYOID || returnType == ANYELEMENTOID ||
 183                  genericOutParam) && !genericInParam)
 184                 ereport(ERROR,
 185                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 186                                  errmsg("cannot determine result data type"),
 187                                  errdetail("A function returning \"anyarray\" or \"anyelement\" must have at least one argument of either type.")));
 188
 189         if ((returnType == INTERNALOID || internalOutParam) && !internalInParam)
 190                 ereport(ERROR,
 191                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 192                                  errmsg("unsafe use of pseudo-type \"internal\""),
 193                                  errdetail("A function returning \"internal\" must have at least one \"internal\" argument.")));
 194
 195         /*
 196          * don't allow functions of complex types that have the same name as
 197          * existing attributes of the type
 198          */
 199         if (parameterCount == 1 &&
 200                 OidIsValid(parameterTypes->values[0]) &&
 201                 (relid = typeidTypeRelid(parameterTypes->values[0])) != InvalidOid &&
 202                 get_attnum(relid, procedureName) != InvalidAttrNumber)
 203                 ereport(ERROR,
 204                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 205                                  errmsg("\"%s\" is already an attribute of type %s",
 206                                                 procedureName,
 207                                                 format_type_be(parameterTypes->values[0]))));
 208
 209         /*
 210          * All seems OK; prepare the data to be inserted into pg_proc.
 211          */
 212
 213         for (i = 0; i < Natts_pg_proc; ++i)
 214         {
 215                 nulls[i] = ' ';
 216                 values[i] = (Datum) 0;
 217                 replaces[i] = 'r';
 218         }
 219
 220         namestrcpy(&procname, procedureName);
 221         values[Anum_pg_proc_proname - 1] = NameGetDatum(&procname);
 222         values[Anum_pg_proc_pronamespace - 1] = ObjectIdGetDatum(procNamespace);
 223         values[Anum_pg_proc_proowner - 1] = ObjectIdGetDatum(GetUserId());
 224         values[Anum_pg_proc_prolang - 1] = ObjectIdGetDatum(languageObjectId);
 225         values[Anum_pg_proc_proisagg - 1] = BoolGetDatum(isAgg);
 226         values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
 227         values[Anum_pg_proc_proisstrict - 1] = BoolGetDatum(isStrict);
 228         values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
 229         values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
 230         values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
 231         values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
 232         values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(parameterTypes);
 233         if (allParameterTypes != PointerGetDatum(NULL))
 234                 values[Anum_pg_proc_proallargtypes - 1] = allParameterTypes;
 235         else
 236                 nulls[Anum_pg_proc_proallargtypes - 1] = 'n';
 237         if (parameterModes != PointerGetDatum(NULL))
 238                 values[Anum_pg_proc_proargmodes - 1] = parameterModes;
 239         else
 240                 nulls[Anum_pg_proc_proargmodes - 1] = 'n';
 241         if (parameterNames != PointerGetDatum(NULL))
 242                 values[Anum_pg_proc_proargnames - 1] = parameterNames;
 243         else
 244                 nulls[Anum_pg_proc_proargnames - 1] = 'n';
 245         values[Anum_pg_proc_prosrc - 1] = DirectFunctionCall1(textin,
 246                                                                                                         CStringGetDatum(prosrc));
 247         values[Anum_pg_proc_probin - 1] = DirectFunctionCall1(textin,
 248                                                                                                         CStringGetDatum(probin));
 249         /* start out with empty permissions */
 250         nulls[Anum_pg_proc_proacl - 1] = 'n';
 251
 252         rel = heap_open(ProcedureRelationId, RowExclusiveLock);
 253         tupDesc = RelationGetDescr(rel);
 254
 255         /* Check for pre-existing definition */
 256         oldtup = SearchSysCache(PROCNAMEARGSNSP,
 257                                                         PointerGetDatum(procedureName),
 258                                                         PointerGetDatum(parameterTypes),
 259                                                         ObjectIdGetDatum(procNamespace),
 260                                                         0);
 261
 262         if (HeapTupleIsValid(oldtup))
 263         {
 264                 /* There is one; okay to replace it? */
 265                 Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);
 266
 267                 if (!replace)
 268                         ereport(ERROR,
 269                                         (errcode(ERRCODE_DUPLICATE_FUNCTION),
 270                         errmsg("function \"%s\" already exists with same argument types",
 271                                    procedureName)));
 272                 if (!pg_proc_ownercheck(HeapTupleGetOid(oldtup), GetUserId()))
 273                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
 274                                                    procedureName);
 275
 276                 /*
 277                  * Not okay to change the return type of the existing proc, since
 278                  * existing rules, views, etc may depend on the return type.
 279                  */
 280                 if (returnType != oldproc->prorettype ||
 281                         returnsSet != oldproc->proretset)
 282                         ereport(ERROR,
 283                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 284                                          errmsg("cannot change return type of existing function"),
 285                                          errhint("Use DROP FUNCTION first.")));
 286
 287                 /*
 288                  * If it returns RECORD, check for possible change of record type
 289                  * implied by OUT parameters
 290                  */
 291                 if (returnType == RECORDOID)
 292                 {
 293                         TupleDesc       olddesc;
 294                         TupleDesc       newdesc;
 295
 296                         olddesc = build_function_result_tupdesc_t(oldtup);
 297                         newdesc = build_function_result_tupdesc_d(allParameterTypes,
 298                                                                                                           parameterModes,
 299                                                                                                           parameterNames);
 300                         if (olddesc == NULL && newdesc == NULL)
 301                                  /* ok, both are runtime-defined RECORDs */ ;
 302                         else if (olddesc == NULL || newdesc == NULL ||
 303                                          !equalTupleDescs(olddesc, newdesc))
 304                                 ereport(ERROR,
 305                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 306                                         errmsg("cannot change return type of existing function"),
 307                                 errdetail("Row type defined by OUT parameters is different."),
 308                                                  errhint("Use DROP FUNCTION first.")));
 309                 }
 310
 311                 /* Can't change aggregate status, either */
 312                 if (oldproc->proisagg != isAgg)
 313                 {
 314                         if (oldproc->proisagg)
 315                                 ereport(ERROR,
 316                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 317                                                  errmsg("function \"%s\" is an aggregate",
 318                                                                 procedureName)));
 319                         else
 320                                 ereport(ERROR,
 321                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 322                                                  errmsg("function \"%s\" is not an aggregate",
 323                                                                 procedureName)));
 324                 }
 325
 326                 /* do not change existing ownership or permissions, either */
 327                 replaces[Anum_pg_proc_proowner - 1] = ' ';
 328                 replaces[Anum_pg_proc_proacl - 1] = ' ';
 329
 330                 /* Okay, do it... */
 331                 tup = heap_modifytuple(oldtup, tupDesc, values, nulls, replaces);
 332                 simple_heap_update(rel, &tup->t_self, tup);
 333
 334                 ReleaseSysCache(oldtup);
 335                 is_update = true;
 336         }
 337         else
 338         {
 339                 /* Creating a new procedure */
 340                 tup = heap_formtuple(tupDesc, values, nulls);
 341                 simple_heap_insert(rel, tup);
 342                 is_update = false;
 343         }
 344
 345         /* Need to update indexes for either the insert or update case */
 346         CatalogUpdateIndexes(rel, tup);
 347
 348         retval = HeapTupleGetOid(tup);
 349
 350         /*
 351          * Create dependencies for the new function.  If we are updating an
 352          * existing function, first delete any existing pg_depend entries.
 353          */
 354         if (is_update)
 355         {
 356                 deleteDependencyRecordsFor(ProcedureRelationId, retval);
 357                 deleteSharedDependencyRecordsFor(ProcedureRelationId, retval);
 358         }
 359
 360         myself.classId = ProcedureRelationId;
 361         myself.objectId = retval;
 362         myself.objectSubId = 0;
 363
 364         /* dependency on namespace */
 365         referenced.classId = NamespaceRelationId;
 366         referenced.objectId = procNamespace;
 367         referenced.objectSubId = 0;
 368         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 369
 370         /* dependency on implementation language */
 371         referenced.classId = LanguageRelationId;
 372         referenced.objectId = languageObjectId;
 373         referenced.objectSubId = 0;
 374         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 375
 376         /* dependency on return type */
 377         referenced.classId = TypeRelationId;
 378         referenced.objectId = returnType;
 379         referenced.objectSubId = 0;
 380         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 381
 382         /* dependency on parameter types */
 383         for (i = 0; i < allParamCount; i++)
 384         {
 385                 referenced.classId = TypeRelationId;
 386                 referenced.objectId = allParams[i];
 387                 referenced.objectSubId = 0;
 388                 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 389         }
 390
 391         /* dependency on owner */
 392         recordDependencyOnOwner(ProcedureRelationId, retval, GetUserId());
 393
 394         heap_freetuple(tup);
 395
 396         heap_close(rel, RowExclusiveLock);
 397
 398         /* Verify function body */
 399         if (OidIsValid(languageValidator))
 400         {
 401                 /* Advance command counter so new tuple can be seen by validator */
 402                 CommandCounterIncrement();
 403                 OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
 404         }
 405
 406         return retval;
 407 }
 408
 409
 410
 411 /*
 412  * Validator for internal functions
 413  *
 414  * Check that the given internal function name (the "prosrc" value) is
 415  * a known builtin function.
 416  */
 417 Datum
 418 fmgr_internal_validator(PG_FUNCTION_ARGS)
 419 {
 420         Oid                     funcoid = PG_GETARG_OID(0);
 421         HeapTuple       tuple;
 422         Form_pg_proc proc;
 423         bool            isnull;
 424         Datum           tmp;
 425         char       *prosrc;
 426
 427         /*
 428          * We do not honor check_function_bodies since it's unlikely the function
 429          * name will be found later if it isn't there now.
 430          */
 431
 432         tuple = SearchSysCache(PROCOID,
 433                                                    ObjectIdGetDatum(funcoid),
 434                                                    0, 0, 0);
 435         if (!HeapTupleIsValid(tuple))
 436                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 437         proc = (Form_pg_proc) GETSTRUCT(tuple);
 438
 439         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 440         if (isnull)
 441                 elog(ERROR, "null prosrc");
 442         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 443
 444         if (fmgr_internal_function(prosrc) == InvalidOid)
 445                 ereport(ERROR,
 446                                 (errcode(ERRCODE_UNDEFINED_FUNCTION),
 447                                  errmsg("there is no built-in function named \"%s\"",
 448                                                 prosrc)));
 449
 450         ReleaseSysCache(tuple);
 451
 452         PG_RETURN_VOID();
 453 }
 454
 455
 456
 457 /*
 458  * Validator for C language functions
 459  *
 460  * Make sure that the library file exists, is loadable, and contains
 461  * the specified link symbol. Also check for a valid function
 462  * information record.
 463  */
 464 Datum
 465 fmgr_c_validator(PG_FUNCTION_ARGS)
 466 {
 467         Oid                     funcoid = PG_GETARG_OID(0);
 468         void       *libraryhandle;
 469         HeapTuple       tuple;
 470         Form_pg_proc proc;
 471         bool            isnull;
 472         Datum           tmp;
 473         char       *prosrc;
 474         char       *probin;
 475
 476         /*
 477          * It'd be most consistent to skip the check if !check_function_bodies,
 478          * but the purpose of that switch is to be helpful for pg_dump loading,
 479          * and for pg_dump loading it's much better if we *do* check.
 480          */
 481
 482         tuple = SearchSysCache(PROCOID,
 483                                                    ObjectIdGetDatum(funcoid),
 484                                                    0, 0, 0);
 485         if (!HeapTupleIsValid(tuple))
 486                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 487         proc = (Form_pg_proc) GETSTRUCT(tuple);
 488
 489         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 490         if (isnull)
 491                 elog(ERROR, "null prosrc");
 492         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 493
 494         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_probin, &isnull);
 495         if (isnull)
 496                 elog(ERROR, "null probin");
 497         probin = DatumGetCString(DirectFunctionCall1(textout, tmp));
 498
 499         (void) load_external_function(probin, prosrc, true, &libraryhandle);
 500         (void) fetch_finfo_record(libraryhandle, prosrc);
 501
 502         ReleaseSysCache(tuple);
 503
 504         PG_RETURN_VOID();
 505 }
 506
 507
 508 /*
 509  * Validator for SQL language functions
 510  *
 511  * Parse it here in order to be sure that it contains no syntax errors.
 512  */
 513 Datum
 514 fmgr_sql_validator(PG_FUNCTION_ARGS)
 515 {
 516         Oid                     funcoid = PG_GETARG_OID(0);
 517         HeapTuple       tuple;
 518         Form_pg_proc proc;
 519         List       *querytree_list;
 520         bool            isnull;
 521         Datum           tmp;
 522         char       *prosrc;
 523         ErrorContextCallback sqlerrcontext;
 524         bool            haspolyarg;
 525         int                     i;
 526
 527         tuple = SearchSysCache(PROCOID,
 528                                                    ObjectIdGetDatum(funcoid),
 529                                                    0, 0, 0);
 530         if (!HeapTupleIsValid(tuple))
 531                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 532         proc = (Form_pg_proc) GETSTRUCT(tuple);
 533
 534         /* Disallow pseudotype result */
 535         /* except for RECORD, VOID, ANYARRAY, or ANYELEMENT */
 536         if (get_typtype(proc->prorettype) == 'p' &&
 537                 proc->prorettype != RECORDOID &&
 538                 proc->prorettype != VOIDOID &&
 539                 proc->prorettype != ANYARRAYOID &&
 540                 proc->prorettype != ANYELEMENTOID)
 541                 ereport(ERROR,
 542                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 543                                  errmsg("SQL functions cannot return type %s",
 544                                                 format_type_be(proc->prorettype))));
 545
 546         /* Disallow pseudotypes in arguments */
 547         /* except for ANYARRAY or ANYELEMENT */
 548         haspolyarg = false;
 549         for (i = 0; i < proc->pronargs; i++)
 550         {
 551                 if (get_typtype(proc->proargtypes.values[i]) == 'p')
 552                 {
 553                         if (proc->proargtypes.values[i] == ANYARRAYOID ||
 554                                 proc->proargtypes.values[i] == ANYELEMENTOID)
 555                                 haspolyarg = true;
 556                         else
 557                                 ereport(ERROR,
 558                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 559                                          errmsg("SQL functions cannot have arguments of type %s",
 560                                                         format_type_be(proc->proargtypes.values[i]))));
 561                 }
 562         }
 563
 564         /* Postpone body checks if !check_function_bodies */
 565         if (check_function_bodies)
 566         {
 567                 tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 568                 if (isnull)
 569                         elog(ERROR, "null prosrc");
 570
 571                 prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 572
 573                 /*
 574                  * Setup error traceback support for ereport().
 575                  */
 576                 sqlerrcontext.callback = sql_function_parse_error_callback;
 577                 sqlerrcontext.arg = tuple;
 578                 sqlerrcontext.previous = error_context_stack;
 579                 error_context_stack = &sqlerrcontext;
 580
 581                 /*
 582                  * We can't do full prechecking of the function definition if there
 583                  * are any polymorphic input types, because actual datatypes of
 584                  * expression results will be unresolvable.  The check will be done at
 585                  * runtime instead.
 586                  *
 587                  * We can run the text through the raw parser though; this will at least
 588                  * catch silly syntactic errors.
 589                  */
 590                 if (!haspolyarg)
 591                 {
 592                         querytree_list = pg_parse_and_rewrite(prosrc,
 593                                                                                                   proc->proargtypes.values,
 594                                                                                                   proc->pronargs);
 595                         (void) check_sql_fn_retval(funcoid, proc->prorettype,
 596                                                                            querytree_list, NULL);
 597                 }
 598                 else
 599                         querytree_list = pg_parse_query(prosrc);
 600
 601                 error_context_stack = sqlerrcontext.previous;
 602         }
 603
 604         ReleaseSysCache(tuple);
 605
 606         PG_RETURN_VOID();
 607 }
 608
 609 /*
 610  * Error context callback for handling errors in SQL function definitions
 611  */
 612 static void
 613 sql_function_parse_error_callback(void *arg)
 614 {
 615         HeapTuple       tuple = (HeapTuple) arg;
 616         Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tuple);
 617         bool            isnull;
 618         Datum           tmp;
 619         char       *prosrc;
 620
 621         /* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
 622         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 623         if (isnull)
 624                 elog(ERROR, "null prosrc");
 625         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 626
 627         if (!function_parse_error_transpose(prosrc))
 628         {
 629                 /* If it's not a syntax error, push info onto context stack */
 630                 errcontext("SQL function \"%s\"", NameStr(proc->proname));
 631         }
 632
 633         pfree(prosrc);
 634 }
 635
 636 /*
 637  * Adjust a syntax error occurring inside the function body of a CREATE
 638  * FUNCTION command.  This can be used by any function validator, not only
 639  * for SQL-language functions.  It is assumed that the syntax error position
 640  * is initially relative to the function body string (as passed in).  If
 641  * possible, we adjust the position to reference the original CREATE command;
 642  * if we can't manage that, we set up an "internal query" syntax error instead.
 643  *
 644  * Returns true if a syntax error was processed, false if not.
 645  */
 646 bool
 647 function_parse_error_transpose(const char *prosrc)
 648 {
 649         int                     origerrposition;
 650         int                     newerrposition;
 651         const char *queryText;
 652
 653         /*
 654          * Nothing to do unless we are dealing with a syntax error that has a
 655          * cursor position.
 656          *
 657          * Some PLs may prefer to report the error position as an internal error to
 658          * begin with, so check that too.
 659          */
 660         origerrposition = geterrposition();
 661         if (origerrposition <= 0)
 662         {
 663                 origerrposition = getinternalerrposition();
 664                 if (origerrposition <= 0)
 665                         return false;
 666         }
 667
 668         /* We can get the original query text from the active portal (hack...) */
 669         Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
 670         queryText = ActivePortal->sourceText;
 671
 672         /* Try to locate the prosrc in the original text */
 673         newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);
 674
 675         if (newerrposition > 0)
 676         {
 677                 /* Successful, so fix error position to reference original query */
 678                 errposition(newerrposition);
 679                 /* Get rid of any report of the error as an "internal query" */
 680                 internalerrposition(0);
 681                 internalerrquery(NULL);
 682         }
 683         else
 684         {
 685                 /*
 686                  * If unsuccessful, convert the position to an internal position
 687                  * marker and give the function text as the internal query.
 688                  */
 689                 errposition(0);
 690                 internalerrposition(origerrposition);
 691                 internalerrquery(prosrc);
 692         }
 693
 694         return true;
 695 }
 696
 697 /*
 698  * Try to locate the string literal containing the function body in the
 699  * given text of the CREATE FUNCTION command.  If successful, return the
 700  * character (not byte) index within the command corresponding to the
 701  * given character index within the literal.  If not successful, return 0.
 702  */
 703 static int
 704 match_prosrc_to_query(const char *prosrc, const char *queryText,
 705                                           int cursorpos)
 706 {
 707         /*
 708          * Rather than fully parsing the CREATE FUNCTION command, we just scan the
 709          * command looking for $prosrc$ or 'prosrc'.  This could be fooled (though
 710          * not in any very probable scenarios), so fail if we find more than one
 711          * match.
 712          */
 713         int                     prosrclen = strlen(prosrc);
 714         int                     querylen = strlen(queryText);
 715         int                     matchpos = 0;
 716         int                     curpos;
 717         int                     newcursorpos;
 718
 719         for (curpos = 0; curpos < querylen - prosrclen; curpos++)
 720         {
 721                 if (queryText[curpos] == '$' &&
 722                         strncmp(prosrc, &queryText[curpos + 1], prosrclen) == 0 &&
 723                         queryText[curpos + 1 + prosrclen] == '$')
 724                 {
 725                         /*
 726                          * Found a $foo$ match.  Since there are no embedded quoting
 727                          * characters in a dollar-quoted literal, we don't have to do any
 728                          * fancy arithmetic; just offset by the starting position.
 729                          */
 730                         if (matchpos)
 731                                 return 0;               /* multiple matches, fail */
 732                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 733                                 + cursorpos;
 734                 }
 735                 else if (queryText[curpos] == '\'' &&
 736                                  match_prosrc_to_literal(prosrc, &queryText[curpos + 1],
 737                                                                                  cursorpos, &newcursorpos))
 738                 {
 739                         /*
 740                          * Found a 'foo' match.  match_prosrc_to_literal() has adjusted
 741                          * for any quotes or backslashes embedded in the literal.
 742                          */
 743                         if (matchpos)
 744                                 return 0;               /* multiple matches, fail */
 745                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 746                                 + newcursorpos;
 747                 }
 748         }
 749
 750         return matchpos;
 751 }
 752
 753 /*
 754  * Try to match the given source text to a single-quoted literal.
 755  * If successful, adjust newcursorpos to correspond to the character
 756  * (not byte) index corresponding to cursorpos in the source text.
 757  *
 758  * At entry, literal points just past a ' character.  We must check for the
 759  * trailing quote.
 760  */
 761 static bool
 762 match_prosrc_to_literal(const char *prosrc, const char *literal,
 763                                                 int cursorpos, int *newcursorpos)
 764 {
 765         int                     newcp = cursorpos;
 766         int                     chlen;
 767
 768         /*
 769          * This implementation handles backslashes and doubled quotes in the
 770          * string literal.      It does not handle the SQL syntax for literals
 771          * continued across line boundaries.
 772          *
 773          * We do the comparison a character at a time, not a byte at a time, so that
 774          * we can do the correct cursorpos math.
 775          */
 776         while (*prosrc)
 777         {
 778                 cursorpos--;                    /* characters left before cursor */
 779
 780                 /*
 781                  * Check for backslashes and doubled quotes in the literal; adjust
 782                  * newcp when one is found before the cursor.
 783                  */
 784                 if (*literal == '\\')
 785                 {
 786                         literal++;
 787                         if (cursorpos > 0)
 788                                 newcp++;
 789                 }
 790                 else if (*literal == '\'')
 791                 {
 792                         if (literal[1] != '\'')
 793                                 goto fail;
 794                         literal++;
 795                         if (cursorpos > 0)
 796                                 newcp++;
 797                 }
 798                 chlen = pg_mblen(prosrc);
 799                 if (strncmp(prosrc, literal, chlen) != 0)
 800                         goto fail;
 801                 prosrc += chlen;
 802                 literal += chlen;
 803         }
 804
 805         if (*literal == '\'' && literal[1] != '\'')
 806         {
 807                 /* success */
 808                 *newcursorpos = newcp;
 809                 return true;
 810         }
 811
 812 fail:
 813         /* Must set *newcursorpos to suppress compiler warning */
 814         *newcursorpos = newcp;
 815         return false;
 816 }