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postgresql/src/backend/commands/dbcommands.c

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/*-------------------------------------------------------------------------
*
* dbcommands.c
* Database management commands (create/drop database).
*
* Note: database creation/destruction commands take ExclusiveLock on
* pg_database to ensure that no two proceed in parallel. We must use
* at least this level of locking to ensure that no two backends try to
* write the flat-file copy of pg_database at once. We avoid using
* AccessExclusiveLock since there's no need to lock out ordinary readers
* of pg_database.
*
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.164 2005/06/30 00:00:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_database.h"
#include "catalog/pg_tablespace.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/tablespace.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "postmaster/bgwriter.h"
#include "storage/fd.h"
#include "storage/freespace.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/flatfiles.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/* non-export function prototypes */
static bool get_db_info(const char *name, Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP,
TransactionId *dbVacuumXidP, TransactionId *dbFrozenXidP,
Oid *dbTablespace);
static bool have_createdb_privilege(void);
static void remove_dbtablespaces(Oid db_id);
/*
* CREATE DATABASE
*/
void
createdb(const CreatedbStmt *stmt)
{
HeapScanDesc scan;
Relation rel;
Oid src_dboid;
Oid src_owner;
int src_encoding;
bool src_istemplate;
bool src_allowconn;
Oid src_lastsysoid;
TransactionId src_vacuumxid;
TransactionId src_frozenxid;
Oid src_deftablespace;
Oid dst_deftablespace;
Relation pg_database_rel;
HeapTuple tuple;
TupleDesc pg_database_dsc;
Datum new_record[Natts_pg_database];
char new_record_nulls[Natts_pg_database];
Oid dboid;
Oid datdba;
ListCell *option;
DefElem *dtablespacename = NULL;
DefElem *downer = NULL;
DefElem *dtemplate = NULL;
DefElem *dencoding = NULL;
char *dbname = stmt->dbname;
char *dbowner = NULL;
const char *dbtemplate = NULL;
int encoding = -1;
#ifndef WIN32
char buf[2 * MAXPGPATH + 100];
#endif
/* don't call this in a transaction block */
PreventTransactionChain((void *) stmt, "CREATE DATABASE");
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
if (strcmp(defel->defname, "tablespace") == 0)
{
if (dtablespacename)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
dtablespacename = defel;
}
else if (strcmp(defel->defname, "owner") == 0)
{
if (downer)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
downer = defel;
}
else if (strcmp(defel->defname, "template") == 0)
{
if (dtemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
dtemplate = defel;
}
else if (strcmp(defel->defname, "encoding") == 0)
{
if (dencoding)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
dencoding = defel;
}
else if (strcmp(defel->defname, "location") == 0)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("LOCATION is not supported anymore"),
errhint("Consider using tablespaces instead.")));
}
else
elog(ERROR, "option \"%s\" not recognized",
defel->defname);
}
if (downer && downer->arg)
dbowner = strVal(downer->arg);
if (dtemplate && dtemplate->arg)
dbtemplate = strVal(dtemplate->arg);
if (dencoding && dencoding->arg)
{
const char *encoding_name;
if (IsA(dencoding->arg, Integer))
{
encoding = intVal(dencoding->arg);
encoding_name = pg_encoding_to_char(encoding);
if (strcmp(encoding_name, "") == 0 ||
pg_valid_server_encoding(encoding_name) < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%d is not a valid encoding code",
encoding)));
}
else if (IsA(dencoding->arg, String))
{
encoding_name = strVal(dencoding->arg);
if (pg_valid_server_encoding(encoding_name) < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%s is not a valid encoding name",
encoding_name)));
encoding = pg_char_to_encoding(encoding_name);
}
else
elog(ERROR, "unrecognized node type: %d",
nodeTag(dencoding->arg));
}
/* obtain OID of proposed owner */
if (dbowner)
datdba = get_roleid_checked(dbowner);
else
datdba = GetUserId();
if (is_member_of_role(GetUserId(), datdba))
{
/* creating database for self: createdb is required */
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create database")));
}
else
{
/* creating database for someone else: must be superuser */
/* note that the someone else need not have any permissions */
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to create database for another user")));
}
/*
* Check for db name conflict. There is a race condition here, since
* another backend could create the same DB name before we commit.
* However, holding an exclusive lock on pg_database for the whole
* time we are copying the source database doesn't seem like a good
* idea, so accept possibility of race to create. We will check again
* after we grab the exclusive lock.
*/
if (get_db_info(dbname, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
/*
* Lookup database (template) to be cloned.
*/
if (!dbtemplate)
dbtemplate = "template1"; /* Default template database name */
if (!get_db_info(dbtemplate, &src_dboid, &src_owner, &src_encoding,
&src_istemplate, &src_allowconn, &src_lastsysoid,
&src_vacuumxid, &src_frozenxid, &src_deftablespace))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("template database \"%s\" does not exist", dbtemplate)));
/*
* Permission check: to copy a DB that's not marked datistemplate, you
* must be superuser or the owner thereof.
*/
if (!src_istemplate)
{
if (!pg_database_ownercheck(src_dboid, GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to copy database \"%s\"",
dbtemplate)));
}
/*
* The source DB can't have any active backends, except this one
* (exception is to allow CREATE DB while connected to template1).
* Otherwise we might copy inconsistent data. This check is not
* bulletproof, since someone might connect while we are copying...
*/
if (DatabaseHasActiveBackends(src_dboid, true))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("source database \"%s\" is being accessed by other users",
dbtemplate)));
/* If encoding is defaulted, use source's encoding */
if (encoding < 0)
encoding = src_encoding;
/* Some encodings are client only */
if (!PG_VALID_BE_ENCODING(encoding))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid server encoding %d", encoding)));
/* Resolve default tablespace for new database */
if (dtablespacename && dtablespacename->arg)
{
char *tablespacename;
AclResult aclresult;
tablespacename = strVal(dtablespacename->arg);
dst_deftablespace = get_tablespace_oid(tablespacename);
if (!OidIsValid(dst_deftablespace))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
tablespacename)));
/* check permissions */
aclresult = pg_tablespace_aclcheck(dst_deftablespace, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
tablespacename);
/*
* If we are trying to change the default tablespace of the template,
* we require that the template not have any files in the new default
* tablespace. This is necessary because otherwise the copied
* database would contain pg_class rows that refer to its default
* tablespace both explicitly (by OID) and implicitly (as zero), which
* would cause problems. For example another CREATE DATABASE using
* the copied database as template, and trying to change its default
* tablespace again, would yield outright incorrect results (it would
* improperly move tables to the new default tablespace that should
* stay in the same tablespace).
*/
if (dst_deftablespace != src_deftablespace)
{
char *srcpath;
struct stat st;
srcpath = GetDatabasePath(src_dboid, dst_deftablespace);
if (stat(srcpath, &st) == 0 &&
S_ISDIR(st.st_mode) &&
!directory_is_empty(srcpath))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot assign new default tablespace \"%s\"",
tablespacename),
errdetail("There is a conflict because database \"%s\" already has some tables in this tablespace.",
dbtemplate)));
pfree(srcpath);
}
}
else
{
/* Use template database's default tablespace */
dst_deftablespace = src_deftablespace;
/* Note there is no additional permission check in this path */
}
/*
* Normally we mark the new database with the same datvacuumxid and
* datfrozenxid as the source. However, if the source is not allowing
* connections then we assume it is fully frozen, and we can set the
* current transaction ID as the xid limits. This avoids immediately
* starting to generate warnings after cloning template0.
*/
if (!src_allowconn)
src_vacuumxid = src_frozenxid = GetCurrentTransactionId();
/*
* Preassign OID for pg_database tuple, so that we can compute db
* path.
*/
dboid = newoid();
/*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy. (We really only need to flush buffers for
* the source database, but bufmgr.c provides no API for that.)
*/
BufferSync();
/*
* Close virtual file descriptors so the kernel has more available for
* the system() calls below.
*/
closeAllVfds();
/*
* Iterate through all tablespaces of the template database, and copy
* each one to the new database.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Oid srctablespace = HeapTupleGetOid(tuple);
Oid dsttablespace;
char *srcpath;
char *dstpath;
struct stat st;
/* No need to copy global tablespace */
if (srctablespace == GLOBALTABLESPACE_OID)
continue;
srcpath = GetDatabasePath(src_dboid, srctablespace);
if (stat(srcpath, &st) < 0 || !S_ISDIR(st.st_mode) ||
directory_is_empty(srcpath))
{
/* Assume we can ignore it */
pfree(srcpath);
continue;
}
if (srctablespace == src_deftablespace)
dsttablespace = dst_deftablespace;
else
dsttablespace = srctablespace;
dstpath = GetDatabasePath(dboid, dsttablespace);
if (stat(dstpath, &st) == 0 || errno != ENOENT)
{
remove_dbtablespaces(dboid);
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Directory \"%s\" already exists.",
dstpath)));
}
#ifndef WIN32
/*
* Copy this subdirectory to the new location
*
* XXX use of cp really makes this code pretty grotty, particularly
* with respect to lack of ability to report errors well. Someday
* rewrite to do it for ourselves.
*/
/* We might need to use cp -R one day for portability */
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'",
srcpath, dstpath);
if (system(buf) != 0)
{
remove_dbtablespaces(dboid);
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
}
#else /* WIN32 */
if (copydir(srcpath, dstpath) != 0)
{
/* copydir should already have given details of its troubles */
remove_dbtablespaces(dboid);
ereport(ERROR,
(errmsg("could not initialize database directory")));
}
#endif /* WIN32 */
/* Record the filesystem change in XLOG */
{
xl_dbase_create_rec xlrec;
XLogRecData rdata[1];
xlrec.db_id = dboid;
xlrec.tablespace_id = dsttablespace;
xlrec.src_db_id = src_dboid;
xlrec.src_tablespace_id = srctablespace;
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_dbase_create_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
(void) XLogInsert(RM_DBASE_ID, XLOG_DBASE_CREATE, rdata);
}
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* Now OK to grab exclusive lock on pg_database.
*/
pg_database_rel = heap_open(DatabaseRelationId, ExclusiveLock);
/* Check to see if someone else created same DB name meanwhile. */
if (get_db_info(dbname, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL))
{
/* Don't hold lock while doing recursive remove */
heap_close(pg_database_rel, ExclusiveLock);
remove_dbtablespaces(dboid);
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
}
/*
* Insert a new tuple into pg_database
*/
pg_database_dsc = RelationGetDescr(pg_database_rel);
/* Form tuple */
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, ' ', sizeof(new_record_nulls));
new_record[Anum_pg_database_datname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbname));
new_record[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(datdba);
new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(false);
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(true);
new_record[Anum_pg_database_datlastsysoid - 1] = ObjectIdGetDatum(src_lastsysoid);
new_record[Anum_pg_database_datvacuumxid - 1] = TransactionIdGetDatum(src_vacuumxid);
new_record[Anum_pg_database_datfrozenxid - 1] = TransactionIdGetDatum(src_frozenxid);
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_deftablespace);
/*
* We deliberately set datconfig and datacl to defaults (NULL), rather
* than copying them from the template database. Copying datacl would
* be a bad idea when the owner is not the same as the template's
* owner. It's more debatable whether datconfig should be copied.
*/
new_record_nulls[Anum_pg_database_datconfig - 1] = 'n';
new_record_nulls[Anum_pg_database_datacl - 1] = 'n';
tuple = heap_formtuple(pg_database_dsc, new_record, new_record_nulls);
HeapTupleSetOid(tuple, dboid); /* override heap_insert's OID
* selection */
simple_heap_insert(pg_database_rel, tuple);
/* Update indexes */
CatalogUpdateIndexes(pg_database_rel, tuple);
/* Close pg_database, but keep exclusive lock till commit */
heap_close(pg_database_rel, NoLock);
/*
* We force a checkpoint before committing. This effectively means
* that committed XLOG_DBASE_CREATE operations will never need to be
* replayed (at least not in ordinary crash recovery; we still have
* to make the XLOG entry for the benefit of PITR operations).
* This avoids two nasty scenarios:
*
* #1: When PITR is off, we don't XLOG the contents of newly created
* indexes; therefore the drop-and-recreate-whole-directory behavior
* of DBASE_CREATE replay would lose such indexes.
*
* #2: Since we have to recopy the source database during DBASE_CREATE
* replay, we run the risk of copying changes in it that were committed
* after the original CREATE DATABASE command but before the system
* crash that led to the replay. This is at least unexpected and at
* worst could lead to inconsistencies, eg duplicate table names.
*
* (Both of these were real bugs in releases 8.0 through 8.0.3.)
*
* In PITR replay, the first of these isn't an issue, and the second
* is only a risk if the CREATE DATABASE and subsequent template
* database change both occur while a base backup is being taken.
* There doesn't seem to be much we can do about that except document
* it as a limitation.
*
* Perhaps if we ever implement CREATE DATABASE in a less cheesy
* way, we can avoid this.
*/
RequestCheckpoint(true, false);
/*
* Set flag to update flat database file at commit.
*/
database_file_update_needed();
}
/*
* DROP DATABASE
*/
void
dropdb(const char *dbname)
{
Oid db_id;
bool db_istemplate;
Relation pgdbrel;
SysScanDesc pgdbscan;
ScanKeyData key;
HeapTuple tup;
PreventTransactionChain((void *) dbname, "DROP DATABASE");
AssertArg(dbname);
if (strcmp(dbname, get_database_name(MyDatabaseId)) == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot drop the currently open database")));
/*
* Obtain exclusive lock on pg_database. We need this to ensure that
* no new backend starts up in the target database while we are
* deleting it. (Actually, a new backend might still manage to start
* up, because it isn't able to lock pg_database while starting. But
* it will detect its error in ReverifyMyDatabase and shut down before
* any serious damage is done. See postinit.c.)
*
* An ExclusiveLock, rather than AccessExclusiveLock, is sufficient
* since ReverifyMyDatabase takes RowShareLock. This allows ordinary
* readers of pg_database to proceed in parallel.
*/
pgdbrel = heap_open(DatabaseRelationId, ExclusiveLock);
if (!get_db_info(dbname, &db_id, NULL, NULL,
&db_istemplate, NULL, NULL, NULL, NULL, NULL))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_DATABASE,
dbname);
/*
* Disallow dropping a DB that is marked istemplate. This is just to
* prevent people from accidentally dropping template0 or template1;
* they can do so if they're really determined ...
*/
if (db_istemplate)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot drop a template database")));
/*
* Check for active backends in the target database.
*/
if (DatabaseHasActiveBackends(db_id, false))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
dbname)));
/*
* Find the database's tuple by OID (should be unique).
*/
ScanKeyInit(&key,
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(db_id));
pgdbscan = systable_beginscan(pgdbrel, DatabaseOidIndexId, true,
SnapshotNow, 1, &key);
tup = systable_getnext(pgdbscan);
if (!HeapTupleIsValid(tup))
{
/*
* This error should never come up since the existence of the
* database is checked earlier
*/
elog(ERROR, "database \"%s\" doesn't exist despite earlier reports to the contrary",
dbname);
}
/* Remove the database's tuple from pg_database */
simple_heap_delete(pgdbrel, &tup->t_self);
systable_endscan(pgdbscan);
/*
* Delete any comments associated with the database
*
* NOTE: this is probably dead code since any such comments should have
* been in that database, not mine.
*/
DeleteComments(db_id, DatabaseRelationId, 0);
/*
* Drop pages for this database that are in the shared buffer cache.
* This is important to ensure that no remaining backend tries to
* write out a dirty buffer to the dead database later...
*/
DropBuffers(db_id);
/*
* Also, clean out any entries in the shared free space map.
*/
FreeSpaceMapForgetDatabase(db_id);
/*
* On Windows, force a checkpoint so that the bgwriter doesn't hold any
* open files, which would cause rmdir() to fail.
*/
#ifdef WIN32
RequestCheckpoint(true, false);
#endif
/*
* Remove all tablespace subdirs belonging to the database.
*/
remove_dbtablespaces(db_id);
/* Close pg_database, but keep exclusive lock till commit */
heap_close(pgdbrel, NoLock);
/*
* Set flag to update flat database file at commit.
*/
database_file_update_needed();
}
/*
* Rename database
*/
void
RenameDatabase(const char *oldname, const char *newname)
{
HeapTuple tup,
newtup;
Relation rel;
SysScanDesc scan,
scan2;
ScanKeyData key,
key2;
/*
* Obtain ExclusiveLock so that no new session gets started
* while the rename is in progress.
*/
rel = heap_open(DatabaseRelationId, ExclusiveLock);
ScanKeyInit(&key,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
NameGetDatum(oldname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
SnapshotNow, 1, &key);
tup = systable_getnext(scan);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", oldname)));
/*
* XXX Client applications probably store the current database
* somewhere, so renaming it could cause confusion. On the other
* hand, there may not be an actual problem besides a little
* confusion, so think about this and decide.
*/
if (HeapTupleGetOid(tup) == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("current database may not be renamed")));
/*
* Make sure the database does not have active sessions. Might not be
* necessary, but it's consistent with other database operations.
*/
if (DatabaseHasActiveBackends(HeapTupleGetOid(tup), false))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
oldname)));
/* make sure the new name doesn't exist */
ScanKeyInit(&key2,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
NameGetDatum(newname));
scan2 = systable_beginscan(rel, DatabaseNameIndexId, true,
SnapshotNow, 1, &key2);
if (HeapTupleIsValid(systable_getnext(scan2)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", newname)));
systable_endscan(scan2);
/* must be owner */
if (!pg_database_ownercheck(HeapTupleGetOid(tup), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_DATABASE,
oldname);
/* must have createdb rights */
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to rename database")));
/* rename */
newtup = heap_copytuple(tup);
namestrcpy(&(((Form_pg_database) GETSTRUCT(newtup))->datname), newname);
simple_heap_update(rel, &newtup->t_self, newtup);
CatalogUpdateIndexes(rel, newtup);
systable_endscan(scan);
/* Close pg_database, but keep exclusive lock till commit */
heap_close(rel, NoLock);
/*
* Set flag to update flat database file at commit.
*/
database_file_update_needed();
}
/*
* ALTER DATABASE name SET ...
*/
void
AlterDatabaseSet(AlterDatabaseSetStmt *stmt)
{
char *valuestr;
HeapTuple tuple,
newtuple;
Relation rel;
ScanKeyData scankey;
SysScanDesc scan;
Datum repl_val[Natts_pg_database];
char repl_null[Natts_pg_database];
char repl_repl[Natts_pg_database];
valuestr = flatten_set_variable_args(stmt->variable, stmt->value);
/*
* We don't need ExclusiveLock since we aren't updating the
* flat file.
*/
rel = heap_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
NameGetDatum(stmt->dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
SnapshotNow, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", stmt->dbname)));
if (!pg_database_ownercheck(HeapTupleGetOid(tuple), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_DATABASE,
stmt->dbname);
MemSet(repl_repl, ' ', sizeof(repl_repl));
repl_repl[Anum_pg_database_datconfig - 1] = 'r';
if (strcmp(stmt->variable, "all") == 0 && valuestr == NULL)
{
/* RESET ALL */
repl_null[Anum_pg_database_datconfig - 1] = 'n';
repl_val[Anum_pg_database_datconfig - 1] = (Datum) 0;
}
else
{
Datum datum;
bool isnull;
ArrayType *a;
repl_null[Anum_pg_database_datconfig - 1] = ' ';
datum = heap_getattr(tuple, Anum_pg_database_datconfig,
RelationGetDescr(rel), &isnull);
a = isnull ? NULL : DatumGetArrayTypeP(datum);
if (valuestr)
a = GUCArrayAdd(a, stmt->variable, valuestr);
else
a = GUCArrayDelete(a, stmt->variable);
if (a)
repl_val[Anum_pg_database_datconfig - 1] = PointerGetDatum(a);
else
repl_null[Anum_pg_database_datconfig - 1] = 'n';
}
newtuple = heap_modifytuple(tuple, RelationGetDescr(rel), repl_val, repl_null, repl_repl);
simple_heap_update(rel, &tuple->t_self, newtuple);
/* Update indexes */
CatalogUpdateIndexes(rel, newtuple);
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
heap_close(rel, NoLock);
/*
* We don't bother updating the flat file since ALTER DATABASE SET
* doesn't affect it.
*/
}
/*
* ALTER DATABASE name OWNER TO newowner
*/
void
AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
{
HeapTuple tuple;
Relation rel;
ScanKeyData scankey;
SysScanDesc scan;
Form_pg_database datForm;
/*
* We don't need ExclusiveLock since we aren't updating the
* flat file.
*/
rel = heap_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
NameGetDatum(dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
SnapshotNow, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
datForm = (Form_pg_database) GETSTRUCT(tuple);
/*
* If the new owner is the same as the existing owner, consider the
* command to have succeeded. This is to be consistent with other
* objects.
*/
if (datForm->datdba != newOwnerId)
{
Datum repl_val[Natts_pg_database];
char repl_null[Natts_pg_database];
char repl_repl[Natts_pg_database];
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* must be superuser to change ownership */
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to change owner")));
memset(repl_null, ' ', sizeof(repl_null));
memset(repl_repl, ' ', sizeof(repl_repl));
repl_repl[Anum_pg_database_datdba - 1] = 'r';
repl_val[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = heap_getattr(tuple,
Anum_pg_database_datacl,
RelationGetDescr(rel),
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
datForm->datdba, newOwnerId);
repl_repl[Anum_pg_database_datacl - 1] = 'r';
repl_val[Anum_pg_database_datacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modifytuple(tuple, RelationGetDescr(rel), repl_val, repl_null, repl_repl);
simple_heap_update(rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(rel, newtuple);
heap_freetuple(newtuple);
}
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
heap_close(rel, NoLock);
/*
* We don't bother updating the flat file since ALTER DATABASE OWNER
* doesn't affect it.
*/
}
/*
* Helper functions
*/
static bool
get_db_info(const char *name, Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP,
TransactionId *dbVacuumXidP, TransactionId *dbFrozenXidP,
Oid *dbTablespace)
{
Relation relation;
ScanKeyData scanKey;
SysScanDesc scan;
HeapTuple tuple;
bool gottuple;
AssertArg(name);
/* Caller may wish to grab a better lock on pg_database beforehand... */
relation = heap_open(DatabaseRelationId, AccessShareLock);
ScanKeyInit(&scanKey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
NameGetDatum(name));
scan = systable_beginscan(relation, DatabaseNameIndexId, true,
SnapshotNow, 1, &scanKey);
tuple = systable_getnext(scan);
gottuple = HeapTupleIsValid(tuple);
if (gottuple)
{
Form_pg_database dbform = (Form_pg_database) GETSTRUCT(tuple);
/* oid of the database */
if (dbIdP)
*dbIdP = HeapTupleGetOid(tuple);
/* oid of the owner */
if (ownerIdP)
*ownerIdP = dbform->datdba;
/* character encoding */
if (encodingP)
*encodingP = dbform->encoding;
/* allowed as template? */
if (dbIsTemplateP)
*dbIsTemplateP = dbform->datistemplate;
/* allowing connections? */
if (dbAllowConnP)
*dbAllowConnP = dbform->datallowconn;
/* last system OID used in database */
if (dbLastSysOidP)
*dbLastSysOidP = dbform->datlastsysoid;
/* limit of vacuumed XIDs */
if (dbVacuumXidP)
*dbVacuumXidP = dbform->datvacuumxid;
/* limit of frozen XIDs */
if (dbFrozenXidP)
*dbFrozenXidP = dbform->datfrozenxid;
/* default tablespace for this database */
if (dbTablespace)
*dbTablespace = dbform->dattablespace;
}
systable_endscan(scan);
heap_close(relation, AccessShareLock);
return gottuple;
}
/* Check if current user has createdb privileges */
static bool
have_createdb_privilege(void)
{
bool result = false;
HeapTuple utup;
/* Superusers can always do everything */
if (superuser())
return true;
utup = SearchSysCache(AUTHOID,
ObjectIdGetDatum(GetUserId()),
0, 0, 0);
if (HeapTupleIsValid(utup))
{
result = ((Form_pg_authid) GETSTRUCT(utup))->rolcreatedb;
ReleaseSysCache(utup);
}
return result;
}
/*
* Remove tablespace directories
*
* We don't know what tablespaces db_id is using, so iterate through all
* tablespaces removing <tablespace>/db_id
*/
static void
remove_dbtablespaces(Oid db_id)
{
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 (stat(dstpath, &st) < 0 || !S_ISDIR(st.st_mode))
{
/* Assume we can ignore it */
pfree(dstpath);
continue;
}
if (!rmtree(dstpath, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
dstpath)));
/* Record the filesystem change in XLOG */
{
xl_dbase_drop_rec xlrec;
XLogRecData rdata[1];
xlrec.db_id = db_id;
xlrec.tablespace_id = dsttablespace;
rdata[0].data = (char *) &xlrec;
rdata[0].len = sizeof(xl_dbase_drop_rec);
rdata[0].buffer = InvalidBuffer;
rdata[0].next = NULL;
(void) XLogInsert(RM_DBASE_ID, XLOG_DBASE_DROP, rdata);
}
pfree(dstpath);
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
}
/*
* get_database_oid - given a database name, look up the OID
*
* Returns InvalidOid if database name not found.
*
* This is not actually used in this file, but is exported for use elsewhere.
*/
Oid
get_database_oid(const char *dbname)
{
Relation pg_database;
ScanKeyData entry[1];
SysScanDesc scan;
HeapTuple dbtuple;
Oid oid;
/* There's no syscache for pg_database, so must look the hard way */
pg_database = heap_open(DatabaseRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(pg_database, DatabaseNameIndexId, true,
SnapshotNow, 1, entry);
dbtuple = systable_getnext(scan);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(dbtuple))
oid = HeapTupleGetOid(dbtuple);
else
oid = InvalidOid;
systable_endscan(scan);
heap_close(pg_database, AccessShareLock);
return oid;
}
/*
* get_database_name - given a database OID, look up the name
*
* Returns a palloc'd string, or NULL if no such database.
*
* This is not actually used in this file, but is exported for use elsewhere.
*/
char *
get_database_name(Oid dbid)
{
Relation pg_database;
ScanKeyData entry[1];
SysScanDesc scan;
HeapTuple dbtuple;
char *result;
/* There's no syscache for pg_database, so must look the hard way */
pg_database = heap_open(DatabaseRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(dbid));
scan = systable_beginscan(pg_database, DatabaseOidIndexId, true,
SnapshotNow, 1, entry);
dbtuple = systable_getnext(scan);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(dbtuple))
result = pstrdup(NameStr(((Form_pg_database) GETSTRUCT(dbtuple))->datname));
else
result = NULL;
systable_endscan(scan);
heap_close(pg_database, AccessShareLock);
return result;
}
/*
* DATABASE resource manager's routines
*/
void
dbase_redo(XLogRecPtr lsn, XLogRecord *record)
{
uint8 info = record->xl_info & ~XLR_INFO_MASK;
if (info == XLOG_DBASE_CREATE)
{
xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) XLogRecGetData(record);
char *src_path;
char *dst_path;
struct stat st;
#ifndef WIN32
char buf[2 * MAXPGPATH + 100];
#endif
src_path = GetDatabasePath(xlrec->src_db_id, xlrec->src_tablespace_id);
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
/*
* Our theory for replaying a CREATE is to forcibly drop the
* target subdirectory if present, then re-copy the source data.
* This may be more work than needed, but it is simple to
* implement.
*/
if (stat(dst_path, &st) == 0 && S_ISDIR(st.st_mode))
{
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
dst_path)));
}
/*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy. (We really only need to flush buffers for
* the source database, but bufmgr.c provides no API for that.)
*/
BufferSync();
#ifndef WIN32
/*
* Copy this subdirectory to the new location
*
* XXX use of cp really makes this code pretty grotty, particularly
* with respect to lack of ability to report errors well. Someday
* rewrite to do it for ourselves.
*/
/* We might need to use cp -R one day for portability */
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'",
src_path, dst_path);
if (system(buf) != 0)
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
#else /* WIN32 */
if (copydir(src_path, dst_path) != 0)
{
/* copydir should already have given details of its troubles */
ereport(ERROR,
(errmsg("could not initialize database directory")));
}
#endif /* WIN32 */
}
else if (info == XLOG_DBASE_DROP)
{
xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) XLogRecGetData(record);
char *dst_path;
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
/*
* Drop pages for this database that are in the shared buffer
* cache
*/
DropBuffers(xlrec->db_id);
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
dst_path)));
}
else if (info == XLOG_DBASE_CREATE_OLD)
{
xl_dbase_create_rec_old *xlrec = (xl_dbase_create_rec_old *) XLogRecGetData(record);
char *dst_path = xlrec->src_path + strlen(xlrec->src_path) + 1;
struct stat st;
#ifndef WIN32
char buf[2 * MAXPGPATH + 100];
#endif
/*
* Our theory for replaying a CREATE is to forcibly drop the
* target subdirectory if present, then re-copy the source data.
* This may be more work than needed, but it is simple to
* implement.
*/
if (stat(dst_path, &st) == 0 && S_ISDIR(st.st_mode))
{
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
dst_path)));
}
/*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy. (We really only need to flush buffers for
* the source database, but bufmgr.c provides no API for that.)
*/
BufferSync();
#ifndef WIN32
/*
* Copy this subdirectory to the new location
*
* XXX use of cp really makes this code pretty grotty, particularly
* with respect to lack of ability to report errors well. Someday
* rewrite to do it for ourselves.
*/
/* We might need to use cp -R one day for portability */
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'",
xlrec->src_path, dst_path);
if (system(buf) != 0)
ereport(ERROR,
(errmsg("could not initialize database directory"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
#else /* WIN32 */
if (copydir(xlrec->src_path, dst_path) != 0)
{
/* copydir should already have given details of its troubles */
ereport(ERROR,
(errmsg("could not initialize database directory")));
}
#endif /* WIN32 */
}
else if (info == XLOG_DBASE_DROP_OLD)
{
xl_dbase_drop_rec_old *xlrec = (xl_dbase_drop_rec_old *) XLogRecGetData(record);
/*
* Drop pages for this database that are in the shared buffer
* cache
*/
DropBuffers(xlrec->db_id);
if (!rmtree(xlrec->dir_path, true))
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
xlrec->dir_path)));
}
else
elog(PANIC, "dbase_redo: unknown op code %u", info);
}
void
dbase_desc(char *buf, uint8 xl_info, char *rec)
{
uint8 info = xl_info & ~XLR_INFO_MASK;
if (info == XLOG_DBASE_CREATE)
{
xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) rec;
sprintf(buf + strlen(buf), "create db: copy dir %u/%u to %u/%u",
xlrec->src_db_id, xlrec->src_tablespace_id,
xlrec->db_id, xlrec->tablespace_id);
}
else if (info == XLOG_DBASE_DROP)
{
xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) rec;
sprintf(buf + strlen(buf), "drop db: dir %u/%u",
xlrec->db_id, xlrec->tablespace_id);
}
else if (info == XLOG_DBASE_CREATE_OLD)
{
xl_dbase_create_rec_old *xlrec = (xl_dbase_create_rec_old *) rec;
char *dst_path = xlrec->src_path + strlen(xlrec->src_path) + 1;
sprintf(buf + strlen(buf), "create db: %u copy \"%s\" to \"%s\"",
xlrec->db_id, xlrec->src_path, dst_path);
}
else if (info == XLOG_DBASE_DROP_OLD)
{
xl_dbase_drop_rec_old *xlrec = (xl_dbase_drop_rec_old *) rec;
sprintf(buf + strlen(buf), "drop db: %u directory: \"%s\"",
xlrec->db_id, xlrec->dir_path);
}
else
strcat(buf, "UNKNOWN");
}
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