src/backend/commands/conversioncmds.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * conversioncmds.c
   4  *        conversion creation command support code
   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/commands/conversioncmds.c,v 1.34 2008/06/14 18:04:33 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_conversion_fn.h"
  22 #include "catalog/pg_type.h"
  23 #include "commands/conversioncmds.h"
  24 #include "mb/pg_wchar.h"
  25 #include "miscadmin.h"
  26 #include "parser/parse_func.h"
  27 #include "utils/acl.h"
  28 #include "utils/builtins.h"
  29 #include "utils/lsyscache.h"
  30 #include "utils/syscache.h"
  31
  32 static void AlterConversionOwner_internal(Relation rel, Oid conversionOid,
  33                                                           Oid newOwnerId);
  34
  35 /*
  36  * CREATE CONVERSION
  37  */
  38 void
  39 CreateConversionCommand(CreateConversionStmt *stmt)
  40 {
  41         Oid                     namespaceId;
  42         char       *conversion_name;
  43         AclResult       aclresult;
  44         int                     from_encoding;
  45         int                     to_encoding;
  46         Oid                     funcoid;
  47         const char *from_encoding_name = stmt->for_encoding_name;
  48         const char *to_encoding_name = stmt->to_encoding_name;
  49         List       *func_name = stmt->func_name;
  50         static Oid      funcargs[] = {INT4OID, INT4OID, CSTRINGOID, INTERNALOID, INT4OID};
  51
  52         /* Convert list of names to a name and namespace */
  53         namespaceId = QualifiedNameGetCreationNamespace(stmt->conversion_name,
  54                                                                                                         &conversion_name);
  55
  56         /* Check we have creation rights in target namespace */
  57         aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE);
  58         if (aclresult != ACLCHECK_OK)
  59                 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
  60                                            get_namespace_name(namespaceId));
  61
  62         /* Check the encoding names */
  63         from_encoding = pg_char_to_encoding(from_encoding_name);
  64         if (from_encoding < 0)
  65                 ereport(ERROR,
  66                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
  67                                  errmsg("source encoding \"%s\" does not exist",
  68                                                 from_encoding_name)));
  69
  70         to_encoding = pg_char_to_encoding(to_encoding_name);
  71         if (to_encoding < 0)
  72                 ereport(ERROR,
  73                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
  74                                  errmsg("destination encoding \"%s\" does not exist",
  75                                                 to_encoding_name)));
  76
  77         /*
  78          * Check the existence of the conversion function. Function name could be
  79          * a qualified name.
  80          */
  81         funcoid = LookupFuncName(func_name, sizeof(funcargs) / sizeof(Oid),
  82                                                          funcargs, false);
  83
  84         /* Check we have EXECUTE rights for the function */
  85         aclresult = pg_proc_aclcheck(funcoid, GetUserId(), ACL_EXECUTE);
  86         if (aclresult != ACLCHECK_OK)
  87                 aclcheck_error(aclresult, ACL_KIND_PROC,
  88                                            NameListToString(func_name));
  89
  90         /*
  91          * All seem ok, go ahead (possible failure would be a duplicate conversion
  92          * name)
  93          */
  94         ConversionCreate(conversion_name, namespaceId, GetUserId(),
  95                                          from_encoding, to_encoding, funcoid, stmt->def);
  96 }
  97
  98 /*
  99  * DROP CONVERSION
 100  */
 101 void
 102 DropConversionsCommand(DropStmt *drop)
 103 {
 104         ObjectAddresses *objects;
 105         ListCell *cell;
 106
 107         /*
 108          * First we identify all the conversions, then we delete them in a single
 109          * performMultipleDeletions() call.  This is to avoid unwanted
 110          * DROP RESTRICT errors if one of the conversions depends on another.
 111          * (Not that that is very likely, but we may as well do this consistently.)
 112          */
 113         objects = new_object_addresses();
 114
 115         foreach(cell, drop->objects)
 116         {
 117                 List            *name = (List *) lfirst(cell);
 118                 Oid                     conversionOid;
 119                 HeapTuple       tuple;
 120                 Form_pg_conversion con;
 121                 ObjectAddress object;
 122
 123                 conversionOid = FindConversionByName(name);
 124
 125                 if (!OidIsValid(conversionOid))
 126                 {
 127                         if (!drop->missing_ok)
 128                         {
 129                                 ereport(ERROR,
 130                                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 131                                                  errmsg("conversion \"%s\" does not exist",
 132                                                                 NameListToString(name))));
 133                         }
 134                         else
 135                         {
 136                                 ereport(NOTICE,
 137                                                 (errmsg("conversion \"%s\" does not exist, skipping",
 138                                                                 NameListToString(name))));
 139                         }
 140                         continue;
 141                 }
 142
 143                 tuple = SearchSysCache(CONVOID,
 144                                                            ObjectIdGetDatum(conversionOid),
 145                                                            0, 0, 0);
 146                 if (!HeapTupleIsValid(tuple))
 147                         elog(ERROR, "cache lookup failed for conversion %u",
 148                                  conversionOid);
 149                 con = (Form_pg_conversion) GETSTRUCT(tuple);
 150
 151                 /* Permission check: must own conversion or its namespace */
 152                 if (!pg_conversion_ownercheck(conversionOid, GetUserId()) &&
 153                         !pg_namespace_ownercheck(con->connamespace, GetUserId()))
 154                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
 155                                                    NameStr(con->conname));
 156
 157                 object.classId = ConversionRelationId;
 158                 object.objectId = conversionOid;
 159                 object.objectSubId = 0;
 160
 161                 add_exact_object_address(&object, objects);
 162
 163                 ReleaseSysCache(tuple);
 164         }
 165
 166         performMultipleDeletions(objects, drop->behavior);
 167
 168         free_object_addresses(objects);
 169 }
 170
 171 /*
 172  * Rename conversion
 173  */
 174 void
 175 RenameConversion(List *name, const char *newname)
 176 {
 177         Oid                     conversionOid;
 178         Oid                     namespaceOid;
 179         HeapTuple       tup;
 180         Relation        rel;
 181         AclResult       aclresult;
 182
 183         rel = heap_open(ConversionRelationId, RowExclusiveLock);
 184
 185         conversionOid = FindConversionByName(name);
 186         if (!OidIsValid(conversionOid))
 187                 ereport(ERROR,
 188                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 189                                  errmsg("conversion \"%s\" does not exist",
 190                                                 NameListToString(name))));
 191
 192         tup = SearchSysCacheCopy(CONVOID,
 193                                                          ObjectIdGetDatum(conversionOid),
 194                                                          0, 0, 0);
 195         if (!HeapTupleIsValid(tup)) /* should not happen */
 196                 elog(ERROR, "cache lookup failed for conversion %u", conversionOid);
 197
 198         namespaceOid = ((Form_pg_conversion) GETSTRUCT(tup))->connamespace;
 199
 200         /* make sure the new name doesn't exist */
 201         if (SearchSysCacheExists(CONNAMENSP,
 202                                                          CStringGetDatum(newname),
 203                                                          ObjectIdGetDatum(namespaceOid),
 204                                                          0, 0))
 205                 ereport(ERROR,
 206                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
 207                                  errmsg("conversion \"%s\" already exists in schema \"%s\"",
 208                                                 newname, get_namespace_name(namespaceOid))));
 209
 210         /* must be owner */
 211         if (!pg_conversion_ownercheck(conversionOid, GetUserId()))
 212                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
 213                                            NameListToString(name));
 214
 215         /* must have CREATE privilege on namespace */
 216         aclresult = pg_namespace_aclcheck(namespaceOid, GetUserId(), ACL_CREATE);
 217         if (aclresult != ACLCHECK_OK)
 218                 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 219                                            get_namespace_name(namespaceOid));
 220
 221         /* rename */
 222         namestrcpy(&(((Form_pg_conversion) GETSTRUCT(tup))->conname), newname);
 223         simple_heap_update(rel, &tup->t_self, tup);
 224         CatalogUpdateIndexes(rel, tup);
 225
 226         heap_close(rel, NoLock);
 227         heap_freetuple(tup);
 228 }
 229
 230 /*
 231  * Change conversion owner, by name
 232  */
 233 void
 234 AlterConversionOwner(List *name, Oid newOwnerId)
 235 {
 236         Oid                     conversionOid;
 237         Relation        rel;
 238
 239         rel = heap_open(ConversionRelationId, RowExclusiveLock);
 240
 241         conversionOid = FindConversionByName(name);
 242         if (!OidIsValid(conversionOid))
 243                 ereport(ERROR,
 244                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 245                                  errmsg("conversion \"%s\" does not exist",
 246                                                 NameListToString(name))));
 247
 248         AlterConversionOwner_internal(rel, conversionOid, newOwnerId);
 249
 250         heap_close(rel, NoLock);
 251 }
 252
 253 /*
 254  * Change conversion owner, by oid
 255  */
 256 void
 257 AlterConversionOwner_oid(Oid conversionOid, Oid newOwnerId)
 258 {
 259         Relation        rel;
 260
 261         rel = heap_open(ConversionRelationId, RowExclusiveLock);
 262
 263         AlterConversionOwner_internal(rel, conversionOid, newOwnerId);
 264
 265         heap_close(rel, NoLock);
 266 }
 267
 268 /*
 269  * AlterConversionOwner_internal
 270  *
 271  * Internal routine for changing the owner.  rel must be pg_conversion, already
 272  * open and suitably locked; it will not be closed.
 273  */
 274 static void
 275 AlterConversionOwner_internal(Relation rel, Oid conversionOid, Oid newOwnerId)
 276 {
 277         Form_pg_conversion convForm;
 278         HeapTuple       tup;
 279
 280         Assert(RelationGetRelid(rel) == ConversionRelationId);
 281
 282         tup = SearchSysCacheCopy(CONVOID,
 283                                                          ObjectIdGetDatum(conversionOid),
 284                                                          0, 0, 0);
 285         if (!HeapTupleIsValid(tup)) /* should not happen */
 286                 elog(ERROR, "cache lookup failed for conversion %u", conversionOid);
 287
 288         convForm = (Form_pg_conversion) GETSTRUCT(tup);
 289
 290         /*
 291          * If the new owner is the same as the existing owner, consider the
 292          * command to have succeeded.  This is for dump restoration purposes.
 293          */
 294         if (convForm->conowner != newOwnerId)
 295         {
 296                 AclResult       aclresult;
 297
 298                 /* Superusers can always do it */
 299                 if (!superuser())
 300                 {
 301                         /* Otherwise, must be owner of the existing object */
 302                         if (!pg_conversion_ownercheck(HeapTupleGetOid(tup), GetUserId()))
 303                                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
 304                                                            NameStr(convForm->conname));
 305
 306                         /* Must be able to become new owner */
 307                         check_is_member_of_role(GetUserId(), newOwnerId);
 308
 309                         /* New owner must have CREATE privilege on namespace */
 310                         aclresult = pg_namespace_aclcheck(convForm->connamespace,
 311                                                                                           newOwnerId,
 312                                                                                           ACL_CREATE);
 313                         if (aclresult != ACLCHECK_OK)
 314                                 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 315                                                            get_namespace_name(convForm->connamespace));
 316                 }
 317
 318                 /*
 319                  * Modify the owner --- okay to scribble on tup because it's a copy
 320                  */
 321                 convForm->conowner = newOwnerId;
 322
 323                 simple_heap_update(rel, &tup->t_self, tup);
 324
 325                 CatalogUpdateIndexes(rel, tup);
 326
 327                 /* Update owner dependency reference */
 328                 changeDependencyOnOwner(ConversionRelationId, conversionOid,
 329                                                                 newOwnerId);
 330         }
 331
 332         heap_freetuple(tup);
 333 }