granicus.if.org Git - postgresql/blob - src/backend/catalog/pg_conversion.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_conversion.c
   4  *        routines to support manipulation of the pg_conversion 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_conversion.c,v 1.28 2005/10/18 01:06:23 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_conversion.h"
  21 #include "catalog/pg_proc.h"
  22 #include "catalog/namespace.h"
  23 #include "utils/builtins.h"
  24 #include "utils/lsyscache.h"
  25 #include "utils/syscache.h"
  26 #include "utils/catcache.h"
  27 #include "mb/pg_wchar.h"
  28 #include "utils/fmgroids.h"
  29 #include "utils/acl.h"
  30 #include "miscadmin.h"
  31
  32 /*
  33  * ConversionCreate
  34  *
  35  * Add a new tuple to pg_conversion.
  36  */
  37 Oid
  38 ConversionCreate(const char *conname, Oid connamespace,
  39                                  Oid conowner,
  40                                  int32 conforencoding, int32 contoencoding,
  41                                  Oid conproc, bool def)
  42 {
  43         int                     i;
  44         Relation        rel;
  45         TupleDesc       tupDesc;
  46         HeapTuple       tup;
  47         char            nulls[Natts_pg_conversion];
  48         Datum           values[Natts_pg_conversion];
  49         NameData        cname;
  50         Oid                     oid;
  51         ObjectAddress myself,
  52                                 referenced;
  53
  54         /* sanity checks */
  55         if (!conname)
  56                 elog(ERROR, "no conversion name supplied");
  57
  58         /* make sure there is no existing conversion of same name */
  59         if (SearchSysCacheExists(CONNAMENSP,
  60                                                          PointerGetDatum(conname),
  61                                                          ObjectIdGetDatum(connamespace),
  62                                                          0, 0))
  63                 ereport(ERROR,
  64                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
  65                                  errmsg("conversion \"%s\" already exists", conname)));
  66
  67         if (def)
  68         {
  69                 /*
  70                  * make sure there is no existing default <for encoding><to encoding>
  71                  * pair in this name space
  72                  */
  73                 if (FindDefaultConversion(connamespace,
  74                                                                   conforencoding,
  75                                                                   contoencoding))
  76                         ereport(ERROR,
  77                                         (errcode(ERRCODE_DUPLICATE_OBJECT),
  78                                          errmsg("default conversion for %s to %s already exists",
  79                                                         pg_encoding_to_char(conforencoding),
  80                                                         pg_encoding_to_char(contoencoding))));
  81         }
  82
  83         /* open pg_conversion */
  84         rel = heap_open(ConversionRelationId, RowExclusiveLock);
  85         tupDesc = rel->rd_att;
  86
  87         /* initialize nulls and values */
  88         for (i = 0; i < Natts_pg_conversion; i++)
  89         {
  90                 nulls[i] = ' ';
  91                 values[i] = (Datum) NULL;
  92         }
  93
  94         /* form a tuple */
  95         namestrcpy(&cname, conname);
  96         values[Anum_pg_conversion_conname - 1] = NameGetDatum(&cname);
  97         values[Anum_pg_conversion_connamespace - 1] = ObjectIdGetDatum(connamespace);
  98         values[Anum_pg_conversion_conowner - 1] = ObjectIdGetDatum(conowner);
  99         values[Anum_pg_conversion_conforencoding - 1] = Int32GetDatum(conforencoding);
 100         values[Anum_pg_conversion_contoencoding - 1] = Int32GetDatum(contoencoding);
 101         values[Anum_pg_conversion_conproc - 1] = ObjectIdGetDatum(conproc);
 102         values[Anum_pg_conversion_condefault - 1] = BoolGetDatum(def);
 103
 104         tup = heap_formtuple(tupDesc, values, nulls);
 105
 106         /* insert a new tuple */
 107         oid = simple_heap_insert(rel, tup);
 108         Assert(OidIsValid(oid));
 109
 110         /* update the index if any */
 111         CatalogUpdateIndexes(rel, tup);
 112
 113         myself.classId = ConversionRelationId;
 114         myself.objectId = HeapTupleGetOid(tup);
 115         myself.objectSubId = 0;
 116
 117         /* create dependency on conversion procedure */
 118         referenced.classId = ProcedureRelationId;
 119         referenced.objectId = conproc;
 120         referenced.objectSubId = 0;
 121         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 122
 123         /* create dependency on owner */
 124         recordDependencyOnOwner(ConversionRelationId, HeapTupleGetOid(tup),
 125                                                         conowner);
 126
 127         heap_freetuple(tup);
 128         heap_close(rel, RowExclusiveLock);
 129
 130         return oid;
 131 }
 132
 133 /*
 134  * ConversionDrop
 135  *
 136  * Drop a conversion after doing permission checks.
 137  */
 138 void
 139 ConversionDrop(Oid conversionOid, DropBehavior behavior)
 140 {
 141         HeapTuple       tuple;
 142         ObjectAddress object;
 143
 144         tuple = SearchSysCache(CONOID,
 145                                                    ObjectIdGetDatum(conversionOid),
 146                                                    0, 0, 0);
 147         if (!HeapTupleIsValid(tuple))
 148                 elog(ERROR, "cache lookup failed for conversion %u", conversionOid);
 149
 150         if (!superuser() &&
 151                 ((Form_pg_conversion) GETSTRUCT(tuple))->conowner != GetUserId())
 152                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
 153                                   NameStr(((Form_pg_conversion) GETSTRUCT(tuple))->conname));
 154
 155         ReleaseSysCache(tuple);
 156
 157         /*
 158          * Do the deletion
 159          */
 160         object.classId = ConversionRelationId;
 161         object.objectId = conversionOid;
 162         object.objectSubId = 0;
 163
 164         performDeletion(&object, behavior);
 165 }
 166
 167 /*
 168  * RemoveConversionById
 169  *
 170  * Remove a tuple from pg_conversion by Oid. This function is solely
 171  * called inside catalog/dependency.c
 172  */
 173 void
 174 RemoveConversionById(Oid conversionOid)
 175 {
 176         Relation        rel;
 177         HeapTuple       tuple;
 178         HeapScanDesc scan;
 179         ScanKeyData scanKeyData;
 180
 181         ScanKeyInit(&scanKeyData,
 182                                 ObjectIdAttributeNumber,
 183                                 BTEqualStrategyNumber, F_OIDEQ,
 184                                 ObjectIdGetDatum(conversionOid));
 185
 186         /* open pg_conversion */
 187         rel = heap_open(ConversionRelationId, RowExclusiveLock);
 188
 189         scan = heap_beginscan(rel, SnapshotNow,
 190                                                   1, &scanKeyData);
 191
 192         /* search for the target tuple */
 193         if (HeapTupleIsValid(tuple = heap_getnext(scan, ForwardScanDirection)))
 194                 simple_heap_delete(rel, &tuple->t_self);
 195         else
 196                 elog(ERROR, "could not find tuple for conversion %u", conversionOid);
 197         heap_endscan(scan);
 198         heap_close(rel, RowExclusiveLock);
 199 }
 200
 201 /*
 202  * FindDefaultConversion
 203  *
 204  * Find "default" conversion proc by for_encoding and to_encoding in the
 205  * given namespace.
 206  *
 207  * If found, returns the procedure's oid, otherwise InvalidOid.  Note that
 208  * you get the procedure's OID not the conversion's OID!
 209  */
 210 Oid
 211 FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
 212 {
 213         CatCList   *catlist;
 214         HeapTuple       tuple;
 215         Form_pg_conversion body;
 216         Oid                     proc = InvalidOid;
 217         int                     i;
 218
 219         catlist = SearchSysCacheList(CONDEFAULT, 3,
 220                                                                  ObjectIdGetDatum(name_space),
 221                                                                  Int32GetDatum(for_encoding),
 222                                                                  Int32GetDatum(to_encoding),
 223                                                                  0);
 224
 225         for (i = 0; i < catlist->n_members; i++)
 226         {
 227                 tuple = &catlist->members[i]->tuple;
 228                 body = (Form_pg_conversion) GETSTRUCT(tuple);
 229                 if (body->condefault)
 230                 {
 231                         proc = body->conproc;
 232                         break;
 233                 }
 234         }
 235         ReleaseSysCacheList(catlist);
 236         return proc;
 237 }
 238
 239 /*
 240  * FindConversion
 241  *
 242  * Find conversion by namespace and conversion name.
 243  * Returns conversion OID.
 244  */
 245 Oid
 246 FindConversion(const char *conname, Oid connamespace)
 247 {
 248         HeapTuple       tuple;
 249         Oid                     procoid;
 250         Oid                     conoid;
 251         AclResult       aclresult;
 252
 253         /* search pg_conversion by connamespace and conversion name */
 254         tuple = SearchSysCache(CONNAMENSP,
 255                                                    PointerGetDatum(conname),
 256                                                    ObjectIdGetDatum(connamespace),
 257                                                    0, 0);
 258         if (!HeapTupleIsValid(tuple))
 259                 return InvalidOid;
 260
 261         procoid = ((Form_pg_conversion) GETSTRUCT(tuple))->conproc;
 262         conoid = HeapTupleGetOid(tuple);
 263
 264         ReleaseSysCache(tuple);
 265
 266         /* Check we have execute rights for the function */
 267         aclresult = pg_proc_aclcheck(procoid, GetUserId(), ACL_EXECUTE);
 268         if (aclresult != ACLCHECK_OK)
 269                 return InvalidOid;
 270
 271         return conoid;
 272 }
 273
 274 /*
 275  * Execute SQL99's CONVERT function.
 276  *
 277  * CONVERT <left paren> <character value expression>
 278  * USING <form-of-use conversion name> <right paren>
 279  *
 280  * TEXT convert_using(TEXT string, TEXT conversion_name)
 281  */
 282 Datum
 283 pg_convert_using(PG_FUNCTION_ARGS)
 284 {
 285         text       *string = PG_GETARG_TEXT_P(0);
 286         text       *conv_name = PG_GETARG_TEXT_P(1);
 287         text       *retval;
 288         List       *parsed_name;
 289         Oid                     convoid;
 290         HeapTuple       tuple;
 291         Form_pg_conversion body;
 292         char       *str;
 293         char       *result;
 294         int                     len;
 295
 296         /* Convert input string to null-terminated form */
 297         len = VARSIZE(string) - VARHDRSZ;
 298         str = palloc(len + 1);
 299         memcpy(str, VARDATA(string), len);
 300         *(str + len) = '\0';
 301
 302         /* Look up the conversion name */
 303         parsed_name = textToQualifiedNameList(conv_name);
 304         convoid = FindConversionByName(parsed_name);
 305         if (!OidIsValid(convoid))
 306                 ereport(ERROR,
 307                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 308                                  errmsg("conversion \"%s\" does not exist",
 309                                                 NameListToString(parsed_name))));
 310
 311         tuple = SearchSysCache(CONOID,
 312                                                    ObjectIdGetDatum(convoid),
 313                                                    0, 0, 0);
 314         if (!HeapTupleIsValid(tuple))
 315                 elog(ERROR, "cache lookup failed for conversion %u", convoid);
 316         body = (Form_pg_conversion) GETSTRUCT(tuple);
 317
 318         /* Temporary result area should be more than big enough */
 319         result = palloc(len * 4 + 1);
 320
 321         OidFunctionCall5(body->conproc,
 322                                          Int32GetDatum(body->conforencoding),
 323                                          Int32GetDatum(body->contoencoding),
 324                                          CStringGetDatum(str),
 325                                          CStringGetDatum(result),
 326                                          Int32GetDatum(len));
 327
 328         ReleaseSysCache(tuple);
 329
 330         /*
 331          * build text result structure. we cannot use textin() here, since textin
 332          * assumes that input string encoding is same as database encoding.
 333          */
 334         len = strlen(result) + VARHDRSZ;
 335         retval = palloc(len);
 336         VARATT_SIZEP(retval) = len;
 337         memcpy(VARDATA(retval), result, len - VARHDRSZ);
 338
 339         pfree(result);
 340         pfree(str);
 341
 342         PG_RETURN_TEXT_P(retval);
 343 }