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) 1996-2007, 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 1.142 2007/01/05 22:19:25 momjian 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 are either arrays
  53  * of the proper types or NULL.  We declare them Datum, not "ArrayType *",
  54  * 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 {
  76         Oid                     retval;
  77         int                     parameterCount;
  78         int                     allParamCount;
  79         Oid                *allParams;
  80         bool            genericInParam = false;
  81         bool            genericOutParam = false;
  82         bool            internalInParam = false;
  83         bool            internalOutParam = false;
  84         Relation        rel;
  85         HeapTuple       tup;
  86         HeapTuple       oldtup;
  87         char            nulls[Natts_pg_proc];
  88         Datum           values[Natts_pg_proc];
  89         char            replaces[Natts_pg_proc];
  90         Oid                     relid;
  91         NameData        procname;
  92         TupleDesc       tupDesc;
  93         bool            is_update;
  94         ObjectAddress myself,
  95                                 referenced;
  96         int                     i;
  97
  98         /*
  99          * sanity checks
 100          */
 101         Assert(PointerIsValid(prosrc));
 102         Assert(PointerIsValid(probin));
 103
 104         parameterCount = parameterTypes->dim1;
 105         if (parameterCount < 0 || parameterCount > FUNC_MAX_ARGS)
 106                 ereport(ERROR,
 107                                 (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
 108                                  errmsg("functions cannot have more than %d arguments",
 109                                                 FUNC_MAX_ARGS)));
 110         /* note: the above is correct, we do NOT count output arguments */
 111
 112         if (allParameterTypes != PointerGetDatum(NULL))
 113         {
 114                 /*
 115                  * We expect the array to be a 1-D OID array; verify that. We don't
 116                  * need to use deconstruct_array() since the array data is just going
 117                  * to look like a C array of OID values.
 118                  */
 119                 ArrayType  *allParamArray = (ArrayType *) DatumGetPointer(allParameterTypes);
 120
 121                 allParamCount = ARR_DIMS(allParamArray)[0];
 122                 if (ARR_NDIM(allParamArray) != 1 ||
 123                         allParamCount <= 0 ||
 124                         ARR_HASNULL(allParamArray) ||
 125                         ARR_ELEMTYPE(allParamArray) != OIDOID)
 126                         elog(ERROR, "allParameterTypes is not a 1-D Oid array");
 127                 allParams = (Oid *) ARR_DATA_PTR(allParamArray);
 128                 Assert(allParamCount >= parameterCount);
 129                 /* we assume caller got the contents right */
 130         }
 131         else
 132         {
 133                 allParamCount = parameterCount;
 134                 allParams = parameterTypes->values;
 135         }
 136
 137         /*
 138          * Do not allow return type ANYARRAY or ANYELEMENT unless at least one
 139          * input argument is ANYARRAY or ANYELEMENT.  Also, do not allow return
 140          * type INTERNAL unless at least one input argument is INTERNAL.
 141          */
 142         for (i = 0; i < parameterCount; i++)
 143         {
 144                 switch (parameterTypes->values[i])
 145                 {
 146                         case ANYARRAYOID:
 147                         case ANYELEMENTOID:
 148                                 genericInParam = true;
 149                                 break;
 150                         case INTERNALOID:
 151                                 internalInParam = true;
 152                                 break;
 153                 }
 154         }
 155
 156         if (allParameterTypes != PointerGetDatum(NULL))
 157         {
 158                 for (i = 0; i < allParamCount; i++)
 159                 {
 160                         /*
 161                          * We don't bother to distinguish input and output params here, so
 162                          * if there is, say, just an input INTERNAL param then we will
 163                          * still set internalOutParam.  This is OK since we don't really
 164                          * care.
 165                          */
 166                         switch (allParams[i])
 167                         {
 168                                 case ANYARRAYOID:
 169                                 case ANYELEMENTOID:
 170                                         genericOutParam = true;
 171                                         break;
 172                                 case INTERNALOID:
 173                                         internalOutParam = true;
 174                                         break;
 175                         }
 176                 }
 177         }
 178
 179         if ((returnType == ANYARRAYOID || returnType == ANYELEMENTOID ||
 180                  genericOutParam) && !genericInParam)
 181                 ereport(ERROR,
 182                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 183                                  errmsg("cannot determine result data type"),
 184                                  errdetail("A function returning \"anyarray\" or \"anyelement\" must have at least one argument of either type.")));
 185
 186         if ((returnType == INTERNALOID || internalOutParam) && !internalInParam)
 187                 ereport(ERROR,
 188                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 189                                  errmsg("unsafe use of pseudo-type \"internal\""),
 190                                  errdetail("A function returning \"internal\" must have at least one \"internal\" argument.")));
 191
 192         /*
 193          * don't allow functions of complex types that have the same name as
 194          * existing attributes of the type
 195          */
 196         if (parameterCount == 1 &&
 197                 OidIsValid(parameterTypes->values[0]) &&
 198                 (relid = typeidTypeRelid(parameterTypes->values[0])) != InvalidOid &&
 199                 get_attnum(relid, procedureName) != InvalidAttrNumber)
 200                 ereport(ERROR,
 201                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 202                                  errmsg("\"%s\" is already an attribute of type %s",
 203                                                 procedureName,
 204                                                 format_type_be(parameterTypes->values[0]))));
 205
 206         /*
 207          * All seems OK; prepare the data to be inserted into pg_proc.
 208          */
 209
 210         for (i = 0; i < Natts_pg_proc; ++i)
 211         {
 212                 nulls[i] = ' ';
 213                 values[i] = (Datum) 0;
 214                 replaces[i] = 'r';
 215         }
 216
 217         namestrcpy(&procname, procedureName);
 218         values[Anum_pg_proc_proname - 1] = NameGetDatum(&procname);
 219         values[Anum_pg_proc_pronamespace - 1] = ObjectIdGetDatum(procNamespace);
 220         values[Anum_pg_proc_proowner - 1] = ObjectIdGetDatum(GetUserId());
 221         values[Anum_pg_proc_prolang - 1] = ObjectIdGetDatum(languageObjectId);
 222         values[Anum_pg_proc_proisagg - 1] = BoolGetDatum(isAgg);
 223         values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
 224         values[Anum_pg_proc_proisstrict - 1] = BoolGetDatum(isStrict);
 225         values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
 226         values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
 227         values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
 228         values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
 229         values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(parameterTypes);
 230         if (allParameterTypes != PointerGetDatum(NULL))
 231                 values[Anum_pg_proc_proallargtypes - 1] = allParameterTypes;
 232         else
 233                 nulls[Anum_pg_proc_proallargtypes - 1] = 'n';
 234         if (parameterModes != PointerGetDatum(NULL))
 235                 values[Anum_pg_proc_proargmodes - 1] = parameterModes;
 236         else
 237                 nulls[Anum_pg_proc_proargmodes - 1] = 'n';
 238         if (parameterNames != PointerGetDatum(NULL))
 239                 values[Anum_pg_proc_proargnames - 1] = parameterNames;
 240         else
 241                 nulls[Anum_pg_proc_proargnames - 1] = 'n';
 242         values[Anum_pg_proc_prosrc - 1] = DirectFunctionCall1(textin,
 243                                                                                                         CStringGetDatum(prosrc));
 244         values[Anum_pg_proc_probin - 1] = DirectFunctionCall1(textin,
 245                                                                                                         CStringGetDatum(probin));
 246         /* start out with empty permissions */
 247         nulls[Anum_pg_proc_proacl - 1] = 'n';
 248
 249         rel = heap_open(ProcedureRelationId, RowExclusiveLock);
 250         tupDesc = RelationGetDescr(rel);
 251
 252         /* Check for pre-existing definition */
 253         oldtup = SearchSysCache(PROCNAMEARGSNSP,
 254                                                         PointerGetDatum(procedureName),
 255                                                         PointerGetDatum(parameterTypes),
 256                                                         ObjectIdGetDatum(procNamespace),
 257                                                         0);
 258
 259         if (HeapTupleIsValid(oldtup))
 260         {
 261                 /* There is one; okay to replace it? */
 262                 Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);
 263
 264                 if (!replace)
 265                         ereport(ERROR,
 266                                         (errcode(ERRCODE_DUPLICATE_FUNCTION),
 267                         errmsg("function \"%s\" already exists with same argument types",
 268                                    procedureName)));
 269                 if (!pg_proc_ownercheck(HeapTupleGetOid(oldtup), GetUserId()))
 270                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
 271                                                    procedureName);
 272
 273                 /*
 274                  * Not okay to change the return type of the existing proc, since
 275                  * existing rules, views, etc may depend on the return type.
 276                  */
 277                 if (returnType != oldproc->prorettype ||
 278                         returnsSet != oldproc->proretset)
 279                         ereport(ERROR,
 280                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 281                                          errmsg("cannot change return type of existing function"),
 282                                          errhint("Use DROP FUNCTION first.")));
 283
 284                 /*
 285                  * If it returns RECORD, check for possible change of record type
 286                  * implied by OUT parameters
 287                  */
 288                 if (returnType == RECORDOID)
 289                 {
 290                         TupleDesc       olddesc;
 291                         TupleDesc       newdesc;
 292
 293                         olddesc = build_function_result_tupdesc_t(oldtup);
 294                         newdesc = build_function_result_tupdesc_d(allParameterTypes,
 295                                                                                                           parameterModes,
 296                                                                                                           parameterNames);
 297                         if (olddesc == NULL && newdesc == NULL)
 298                                  /* ok, both are runtime-defined RECORDs */ ;
 299                         else if (olddesc == NULL || newdesc == NULL ||
 300                                          !equalTupleDescs(olddesc, newdesc))
 301                                 ereport(ERROR,
 302                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 303                                         errmsg("cannot change return type of existing function"),
 304                                 errdetail("Row type defined by OUT parameters is different."),
 305                                                  errhint("Use DROP FUNCTION first.")));
 306                 }
 307
 308                 /* Can't change aggregate status, either */
 309                 if (oldproc->proisagg != isAgg)
 310                 {
 311                         if (oldproc->proisagg)
 312                                 ereport(ERROR,
 313                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 314                                                  errmsg("function \"%s\" is an aggregate",
 315                                                                 procedureName)));
 316                         else
 317                                 ereport(ERROR,
 318                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 319                                                  errmsg("function \"%s\" is not an aggregate",
 320                                                                 procedureName)));
 321                 }
 322
 323                 /* do not change existing ownership or permissions, either */
 324                 replaces[Anum_pg_proc_proowner - 1] = ' ';
 325                 replaces[Anum_pg_proc_proacl - 1] = ' ';
 326
 327                 /* Okay, do it... */
 328                 tup = heap_modifytuple(oldtup, tupDesc, values, nulls, replaces);
 329                 simple_heap_update(rel, &tup->t_self, tup);
 330
 331                 ReleaseSysCache(oldtup);
 332                 is_update = true;
 333         }
 334         else
 335         {
 336                 /* Creating a new procedure */
 337                 tup = heap_formtuple(tupDesc, values, nulls);
 338                 simple_heap_insert(rel, tup);
 339                 is_update = false;
 340         }
 341
 342         /* Need to update indexes for either the insert or update case */
 343         CatalogUpdateIndexes(rel, tup);
 344
 345         retval = HeapTupleGetOid(tup);
 346
 347         /*
 348          * Create dependencies for the new function.  If we are updating an
 349          * existing function, first delete any existing pg_depend entries.
 350          */
 351         if (is_update)
 352         {
 353                 deleteDependencyRecordsFor(ProcedureRelationId, retval);
 354                 deleteSharedDependencyRecordsFor(ProcedureRelationId, retval);
 355         }
 356
 357         myself.classId = ProcedureRelationId;
 358         myself.objectId = retval;
 359         myself.objectSubId = 0;
 360
 361         /* dependency on namespace */
 362         referenced.classId = NamespaceRelationId;
 363         referenced.objectId = procNamespace;
 364         referenced.objectSubId = 0;
 365         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 366
 367         /* dependency on implementation language */
 368         referenced.classId = LanguageRelationId;
 369         referenced.objectId = languageObjectId;
 370         referenced.objectSubId = 0;
 371         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 372
 373         /* dependency on return type */
 374         referenced.classId = TypeRelationId;
 375         referenced.objectId = returnType;
 376         referenced.objectSubId = 0;
 377         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 378
 379         /* dependency on parameter types */
 380         for (i = 0; i < allParamCount; i++)
 381         {
 382                 referenced.classId = TypeRelationId;
 383                 referenced.objectId = allParams[i];
 384                 referenced.objectSubId = 0;
 385                 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 386         }
 387
 388         /* dependency on owner */
 389         recordDependencyOnOwner(ProcedureRelationId, retval, GetUserId());
 390
 391         heap_freetuple(tup);
 392
 393         heap_close(rel, RowExclusiveLock);
 394
 395         /* Verify function body */
 396         if (OidIsValid(languageValidator))
 397         {
 398                 /* Advance command counter so new tuple can be seen by validator */
 399                 CommandCounterIncrement();
 400                 OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
 401         }
 402
 403         return retval;
 404 }
 405
 406
 407
 408 /*
 409  * Validator for internal functions
 410  *
 411  * Check that the given internal function name (the "prosrc" value) is
 412  * a known builtin function.
 413  */
 414 Datum
 415 fmgr_internal_validator(PG_FUNCTION_ARGS)
 416 {
 417         Oid                     funcoid = PG_GETARG_OID(0);
 418         HeapTuple       tuple;
 419         Form_pg_proc proc;
 420         bool            isnull;
 421         Datum           tmp;
 422         char       *prosrc;
 423
 424         /*
 425          * We do not honor check_function_bodies since it's unlikely the function
 426          * name will be found later if it isn't there now.
 427          */
 428
 429         tuple = SearchSysCache(PROCOID,
 430                                                    ObjectIdGetDatum(funcoid),
 431                                                    0, 0, 0);
 432         if (!HeapTupleIsValid(tuple))
 433                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 434         proc = (Form_pg_proc) GETSTRUCT(tuple);
 435
 436         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 437         if (isnull)
 438                 elog(ERROR, "null prosrc");
 439         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 440
 441         if (fmgr_internal_function(prosrc) == InvalidOid)
 442                 ereport(ERROR,
 443                                 (errcode(ERRCODE_UNDEFINED_FUNCTION),
 444                                  errmsg("there is no built-in function named \"%s\"",
 445                                                 prosrc)));
 446
 447         ReleaseSysCache(tuple);
 448
 449         PG_RETURN_VOID();
 450 }
 451
 452
 453
 454 /*
 455  * Validator for C language functions
 456  *
 457  * Make sure that the library file exists, is loadable, and contains
 458  * the specified link symbol. Also check for a valid function
 459  * information record.
 460  */
 461 Datum
 462 fmgr_c_validator(PG_FUNCTION_ARGS)
 463 {
 464         Oid                     funcoid = PG_GETARG_OID(0);
 465         void       *libraryhandle;
 466         HeapTuple       tuple;
 467         Form_pg_proc proc;
 468         bool            isnull;
 469         Datum           tmp;
 470         char       *prosrc;
 471         char       *probin;
 472
 473         /*
 474          * It'd be most consistent to skip the check if !check_function_bodies,
 475          * but the purpose of that switch is to be helpful for pg_dump loading,
 476          * and for pg_dump loading it's much better if we *do* check.
 477          */
 478
 479         tuple = SearchSysCache(PROCOID,
 480                                                    ObjectIdGetDatum(funcoid),
 481                                                    0, 0, 0);
 482         if (!HeapTupleIsValid(tuple))
 483                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 484         proc = (Form_pg_proc) GETSTRUCT(tuple);
 485
 486         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 487         if (isnull)
 488                 elog(ERROR, "null prosrc");
 489         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 490
 491         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_probin, &isnull);
 492         if (isnull)
 493                 elog(ERROR, "null probin");
 494         probin = DatumGetCString(DirectFunctionCall1(textout, tmp));
 495
 496         (void) load_external_function(probin, prosrc, true, &libraryhandle);
 497         (void) fetch_finfo_record(libraryhandle, prosrc);
 498
 499         ReleaseSysCache(tuple);
 500
 501         PG_RETURN_VOID();
 502 }
 503
 504
 505 /*
 506  * Validator for SQL language functions
 507  *
 508  * Parse it here in order to be sure that it contains no syntax errors.
 509  */
 510 Datum
 511 fmgr_sql_validator(PG_FUNCTION_ARGS)
 512 {
 513         Oid                     funcoid = PG_GETARG_OID(0);
 514         HeapTuple       tuple;
 515         Form_pg_proc proc;
 516         List       *querytree_list;
 517         bool            isnull;
 518         Datum           tmp;
 519         char       *prosrc;
 520         ErrorContextCallback sqlerrcontext;
 521         bool            haspolyarg;
 522         int                     i;
 523
 524         tuple = SearchSysCache(PROCOID,
 525                                                    ObjectIdGetDatum(funcoid),
 526                                                    0, 0, 0);
 527         if (!HeapTupleIsValid(tuple))
 528                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 529         proc = (Form_pg_proc) GETSTRUCT(tuple);
 530
 531         /* Disallow pseudotype result */
 532         /* except for RECORD, VOID, ANYARRAY, or ANYELEMENT */
 533         if (get_typtype(proc->prorettype) == 'p' &&
 534                 proc->prorettype != RECORDOID &&
 535                 proc->prorettype != VOIDOID &&
 536                 proc->prorettype != ANYARRAYOID &&
 537                 proc->prorettype != ANYELEMENTOID)
 538                 ereport(ERROR,
 539                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 540                                  errmsg("SQL functions cannot return type %s",
 541                                                 format_type_be(proc->prorettype))));
 542
 543         /* Disallow pseudotypes in arguments */
 544         /* except for ANYARRAY or ANYELEMENT */
 545         haspolyarg = false;
 546         for (i = 0; i < proc->pronargs; i++)
 547         {
 548                 if (get_typtype(proc->proargtypes.values[i]) == 'p')
 549                 {
 550                         if (proc->proargtypes.values[i] == ANYARRAYOID ||
 551                                 proc->proargtypes.values[i] == ANYELEMENTOID)
 552                                 haspolyarg = true;
 553                         else
 554                                 ereport(ERROR,
 555                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 556                                          errmsg("SQL functions cannot have arguments of type %s",
 557                                                         format_type_be(proc->proargtypes.values[i]))));
 558                 }
 559         }
 560
 561         /* Postpone body checks if !check_function_bodies */
 562         if (check_function_bodies)
 563         {
 564                 tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 565                 if (isnull)
 566                         elog(ERROR, "null prosrc");
 567
 568                 prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 569
 570                 /*
 571                  * Setup error traceback support for ereport().
 572                  */
 573                 sqlerrcontext.callback = sql_function_parse_error_callback;
 574                 sqlerrcontext.arg = tuple;
 575                 sqlerrcontext.previous = error_context_stack;
 576                 error_context_stack = &sqlerrcontext;
 577
 578                 /*
 579                  * We can't do full prechecking of the function definition if there
 580                  * are any polymorphic input types, because actual datatypes of
 581                  * expression results will be unresolvable.  The check will be done at
 582                  * runtime instead.
 583                  *
 584                  * We can run the text through the raw parser though; this will at
 585                  * least catch silly syntactic errors.
 586                  */
 587                 if (!haspolyarg)
 588                 {
 589                         querytree_list = pg_parse_and_rewrite(prosrc,
 590                                                                                                   proc->proargtypes.values,
 591                                                                                                   proc->pronargs);
 592                         (void) check_sql_fn_retval(funcoid, proc->prorettype,
 593                                                                            querytree_list, NULL);
 594                 }
 595                 else
 596                         querytree_list = pg_parse_query(prosrc);
 597
 598                 error_context_stack = sqlerrcontext.previous;
 599         }
 600
 601         ReleaseSysCache(tuple);
 602
 603         PG_RETURN_VOID();
 604 }
 605
 606 /*
 607  * Error context callback for handling errors in SQL function definitions
 608  */
 609 static void
 610 sql_function_parse_error_callback(void *arg)
 611 {
 612         HeapTuple       tuple = (HeapTuple) arg;
 613         Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tuple);
 614         bool            isnull;
 615         Datum           tmp;
 616         char       *prosrc;
 617
 618         /* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
 619         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 620         if (isnull)
 621                 elog(ERROR, "null prosrc");
 622         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 623
 624         if (!function_parse_error_transpose(prosrc))
 625         {
 626                 /* If it's not a syntax error, push info onto context stack */
 627                 errcontext("SQL function \"%s\"", NameStr(proc->proname));
 628         }
 629
 630         pfree(prosrc);
 631 }
 632
 633 /*
 634  * Adjust a syntax error occurring inside the function body of a CREATE
 635  * FUNCTION command.  This can be used by any function validator, not only
 636  * for SQL-language functions.  It is assumed that the syntax error position
 637  * is initially relative to the function body string (as passed in).  If
 638  * possible, we adjust the position to reference the original CREATE command;
 639  * if we can't manage that, we set up an "internal query" syntax error instead.
 640  *
 641  * Returns true if a syntax error was processed, false if not.
 642  */
 643 bool
 644 function_parse_error_transpose(const char *prosrc)
 645 {
 646         int                     origerrposition;
 647         int                     newerrposition;
 648         const char *queryText;
 649
 650         /*
 651          * Nothing to do unless we are dealing with a syntax error that has a
 652          * cursor position.
 653          *
 654          * Some PLs may prefer to report the error position as an internal error
 655          * to begin with, so check that too.
 656          */
 657         origerrposition = geterrposition();
 658         if (origerrposition <= 0)
 659         {
 660                 origerrposition = getinternalerrposition();
 661                 if (origerrposition <= 0)
 662                         return false;
 663         }
 664
 665         /* We can get the original query text from the active portal (hack...) */
 666         Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
 667         queryText = ActivePortal->sourceText;
 668
 669         /* Try to locate the prosrc in the original text */
 670         newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);
 671
 672         if (newerrposition > 0)
 673         {
 674                 /* Successful, so fix error position to reference original query */
 675                 errposition(newerrposition);
 676                 /* Get rid of any report of the error as an "internal query" */
 677                 internalerrposition(0);
 678                 internalerrquery(NULL);
 679         }
 680         else
 681         {
 682                 /*
 683                  * If unsuccessful, convert the position to an internal position
 684                  * marker and give the function text as the internal query.
 685                  */
 686                 errposition(0);
 687                 internalerrposition(origerrposition);
 688                 internalerrquery(prosrc);
 689         }
 690
 691         return true;
 692 }
 693
 694 /*
 695  * Try to locate the string literal containing the function body in the
 696  * given text of the CREATE FUNCTION command.  If successful, return the
 697  * character (not byte) index within the command corresponding to the
 698  * given character index within the literal.  If not successful, return 0.
 699  */
 700 static int
 701 match_prosrc_to_query(const char *prosrc, const char *queryText,
 702                                           int cursorpos)
 703 {
 704         /*
 705          * Rather than fully parsing the CREATE FUNCTION command, we just scan the
 706          * command looking for $prosrc$ or 'prosrc'.  This could be fooled (though
 707          * not in any very probable scenarios), so fail if we find more than one
 708          * match.
 709          */
 710         int                     prosrclen = strlen(prosrc);
 711         int                     querylen = strlen(queryText);
 712         int                     matchpos = 0;
 713         int                     curpos;
 714         int                     newcursorpos;
 715
 716         for (curpos = 0; curpos < querylen - prosrclen; curpos++)
 717         {
 718                 if (queryText[curpos] == '$' &&
 719                         strncmp(prosrc, &queryText[curpos + 1], prosrclen) == 0 &&
 720                         queryText[curpos + 1 + prosrclen] == '$')
 721                 {
 722                         /*
 723                          * Found a $foo$ match.  Since there are no embedded quoting
 724                          * characters in a dollar-quoted literal, we don't have to do any
 725                          * fancy arithmetic; just offset by the starting position.
 726                          */
 727                         if (matchpos)
 728                                 return 0;               /* multiple matches, fail */
 729                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 730                                 + cursorpos;
 731                 }
 732                 else if (queryText[curpos] == '\'' &&
 733                                  match_prosrc_to_literal(prosrc, &queryText[curpos + 1],
 734                                                                                  cursorpos, &newcursorpos))
 735                 {
 736                         /*
 737                          * Found a 'foo' match.  match_prosrc_to_literal() has adjusted
 738                          * for any quotes or backslashes embedded in the literal.
 739                          */
 740                         if (matchpos)
 741                                 return 0;               /* multiple matches, fail */
 742                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 743                                 + newcursorpos;
 744                 }
 745         }
 746
 747         return matchpos;
 748 }
 749
 750 /*
 751  * Try to match the given source text to a single-quoted literal.
 752  * If successful, adjust newcursorpos to correspond to the character
 753  * (not byte) index corresponding to cursorpos in the source text.
 754  *
 755  * At entry, literal points just past a ' character.  We must check for the
 756  * trailing quote.
 757  */
 758 static bool
 759 match_prosrc_to_literal(const char *prosrc, const char *literal,
 760                                                 int cursorpos, int *newcursorpos)
 761 {
 762         int                     newcp = cursorpos;
 763         int                     chlen;
 764
 765         /*
 766          * This implementation handles backslashes and doubled quotes in the
 767          * string literal.      It does not handle the SQL syntax for literals
 768          * continued across line boundaries.
 769          *
 770          * We do the comparison a character at a time, not a byte at a time, so
 771          * that we can do the correct cursorpos math.
 772          */
 773         while (*prosrc)
 774         {
 775                 cursorpos--;                    /* characters left before cursor */
 776
 777                 /*
 778                  * Check for backslashes and doubled quotes in the literal; adjust
 779                  * newcp when one is found before the cursor.
 780                  */
 781                 if (*literal == '\\')
 782                 {
 783                         literal++;
 784                         if (cursorpos > 0)
 785                                 newcp++;
 786                 }
 787                 else if (*literal == '\'')
 788                 {
 789                         if (literal[1] != '\'')
 790                                 goto fail;
 791                         literal++;
 792                         if (cursorpos > 0)
 793                                 newcp++;
 794                 }
 795                 chlen = pg_mblen(prosrc);
 796                 if (strncmp(prosrc, literal, chlen) != 0)
 797                         goto fail;
 798                 prosrc += chlen;
 799                 literal += chlen;
 800         }
 801
 802         if (*literal == '\'' && literal[1] != '\'')
 803         {
 804                 /* success */
 805                 *newcursorpos = newcp;
 806                 return true;
 807         }
 808
 809 fail:
 810         /* Must set *newcursorpos to suppress compiler warning */
 811         *newcursorpos = newcp;
 812         return false;
 813 }