diff options
Diffstat (limited to 'src/backend/commands/dbcommands.c')
| -rw-r--r-- | src/backend/commands/dbcommands.c | 74 |
1 files changed, 68 insertions, 6 deletions
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index d7d4cdbfbc4..cd327bb8d15 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -13,7 +13,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.185 2006/10/04 00:29:51 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.186 2006/10/18 22:44:12 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -58,6 +58,7 @@ static bool get_db_info(const char *name, LOCKMODE lockmode, Oid *dbTablespace); static bool have_createdb_privilege(void); static void remove_dbtablespaces(Oid db_id); +static bool check_db_file_conflict(Oid db_id); /* @@ -336,12 +337,22 @@ createdb(const CreatedbStmt *stmt) errmsg("database \"%s\" already exists", dbname))); /* + * Select an OID for the new database, checking that it doesn't have + * a filename conflict with anything already existing in the tablespace + * directories. + */ + pg_database_rel = heap_open(DatabaseRelationId, RowExclusiveLock); + + do + { + dboid = GetNewOid(pg_database_rel); + } while (check_db_file_conflict(dboid)); + + /* * Insert a new tuple into pg_database. This establishes our ownership of * the new database name (anyone else trying to insert the same name will - * block on the unique index, and fail after we commit). It also assigns - * the OID that the new database will have. + * block on the unique index, and fail after we commit). */ - pg_database_rel = heap_open(DatabaseRelationId, RowExclusiveLock); /* Form tuple */ MemSet(new_record, 0, sizeof(new_record)); @@ -371,7 +382,9 @@ createdb(const CreatedbStmt *stmt) tuple = heap_formtuple(RelationGetDescr(pg_database_rel), new_record, new_record_nulls); - dboid = simple_heap_insert(pg_database_rel, tuple); + HeapTupleSetOid(tuple, dboid); + + simple_heap_insert(pg_database_rel, tuple); /* Update indexes */ CatalogUpdateIndexes(pg_database_rel, tuple); @@ -1216,7 +1229,7 @@ remove_dbtablespaces(Oid db_id) dstpath = GetDatabasePath(db_id, dsttablespace); - if (stat(dstpath, &st) < 0 || !S_ISDIR(st.st_mode)) + if (lstat(dstpath, &st) < 0 || !S_ISDIR(st.st_mode)) { /* Assume we can ignore it */ pfree(dstpath); @@ -1251,6 +1264,55 @@ remove_dbtablespaces(Oid db_id) heap_close(rel, AccessShareLock); } +/* + * Check for existing files that conflict with a proposed new DB OID; + * return TRUE if there are any + * + * If there were a subdirectory in any tablespace matching the proposed new + * OID, we'd get a create failure due to the duplicate name ... and then we'd + * try to remove that already-existing subdirectory during the cleanup in + * remove_dbtablespaces. Nuking existing files seems like a bad idea, so + * instead we make this extra check before settling on the OID of the new + * database. This exactly parallels what GetNewRelFileNode() does for table + * relfilenode values. + */ +static bool +check_db_file_conflict(Oid db_id) +{ + bool result = false; + Relation rel; + HeapScanDesc scan; + HeapTuple tuple; + + rel = heap_open(TableSpaceRelationId, AccessShareLock); + scan = heap_beginscan(rel, SnapshotNow, 0, NULL); + while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) + { + Oid dsttablespace = HeapTupleGetOid(tuple); + char *dstpath; + struct stat st; + + /* Don't mess with the global tablespace */ + if (dsttablespace == GLOBALTABLESPACE_OID) + continue; + + dstpath = GetDatabasePath(db_id, dsttablespace); + + if (lstat(dstpath, &st) == 0) + { + /* Found a conflicting file (or directory, whatever) */ + pfree(dstpath); + result = true; + break; + } + + pfree(dstpath); + } + + heap_endscan(scan); + heap_close(rel, AccessShareLock); + return result; +} /* * get_database_oid - given a database name, look up the OID |