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postgresql/src/backend/commands/dbcommands.c

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/*-------------------------------------------------------------------------
*
* dbcommands.c
* Database management commands (create/drop database).
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.122 2003/09/10 20:24:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/catalog.h"
#include "catalog/pg_database.h"
#include "catalog/pg_shadow.h"
#include "catalog/indexing.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "miscadmin.h"
#include "storage/freespace.h"
#include "storage/sinval.h"
#include "utils/acl.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "mb/pg_wchar.h" /* encoding check */
/* non-export function prototypes */
static bool get_db_info(const char *name, Oid *dbIdP, int4 *ownerIdP,
int *encodingP, bool *dbIsTemplateP, Oid *dbLastSysOidP,
TransactionId *dbVacuumXidP, TransactionId *dbFrozenXidP,
char *dbpath);
static bool have_createdb_privilege(void);
static char *resolve_alt_dbpath(const char *dbpath, Oid dboid);
static bool remove_dbdirs(const char *real_loc, const char *altloc);
/*
* CREATE DATABASE
*/
void
createdb(const CreatedbStmt *stmt)
{
char *nominal_loc;
char *alt_loc;
char *target_dir;
char src_loc[MAXPGPATH];
char buf[2 * MAXPGPATH + 100];
Oid src_dboid;
AclId src_owner;
int src_encoding;
bool src_istemplate;
Oid src_lastsysoid;
TransactionId src_vacuumxid;
TransactionId src_frozenxid;
char src_dbpath[MAXPGPATH];
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;
AclId datdba;
List *option;
DefElem *downer = NULL;
DefElem *dpath = NULL;
DefElem *dtemplate = NULL;
DefElem *dencoding = NULL;
char *dbname = stmt->dbname;
char *dbowner = NULL;
char *dbpath = NULL;
char *dbtemplate = NULL;
int encoding = -1;
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
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, "location") == 0)
{
if (dpath)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
dpath = 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
elog(ERROR, "option \"%s\" not recognized",
defel->defname);
}
if (downer && downer->arg)
dbowner = strVal(downer->arg);
if (dpath && dpath->arg)
dbpath = strVal(dpath->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 sysid of proposed owner */
if (dbowner)
datdba = get_usesysid(dbowner); /* will ereport if no such user */
else
datdba = GetUserId();
if (datdba == GetUserId())
{
/* creating database for self: can be superuser or createdb */
if (!superuser() && !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")));
}
/* don't call this in a transaction block */
PreventTransactionChain((void *) stmt, "CREATE DATABASE");
/* alternate location requires symlinks */
#ifndef HAVE_SYMLINK
if (dbpath != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use an alternate location on this platform")));
#endif
/*
* 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))
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_lastsysoid,
&src_vacuumxid, &src_frozenxid,
src_dbpath))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("template \"%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 (!superuser() && GetUserId() != src_owner)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to copy database \"%s\"",
dbtemplate)));
}
/*
* Determine physical path of source database
*/
alt_loc = resolve_alt_dbpath(src_dbpath, src_dboid);
if (!alt_loc)
alt_loc = GetDatabasePath(src_dboid);
strcpy(src_loc, alt_loc);
/*
* 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 backend encoding %d", encoding)));
/*
* Preassign OID for pg_database tuple, so that we can compute db
* path.
*/
dboid = newoid();
/*
* Compute nominal location (where we will try to access the
* database), and resolve alternate physical location if one is
* specified.
*
* If an alternate location is specified but is the same as the normal
* path, just drop the alternate-location spec (this seems friendlier
* than erroring out). We must test this case to avoid creating a
* circular symlink below.
*/
nominal_loc = GetDatabasePath(dboid);
alt_loc = resolve_alt_dbpath(dbpath, dboid);
if (alt_loc && strcmp(alt_loc, nominal_loc) == 0)
{
alt_loc = NULL;
dbpath = NULL;
}
if (strchr(nominal_loc, '\''))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("database path may not contain single quotes")));
if (alt_loc && strchr(alt_loc, '\''))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("database path may not contain single quotes")));
if (strchr(src_loc, '\''))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("database path may not contain single quotes")));
/* ... otherwise we'd be open to shell exploits below */
/*
* 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...)
*/
BufferSync();
/*
* Close virtual file descriptors so the kernel has more available for
* the mkdir() and system() calls below.
*/
closeAllVfds();
/*
* Check we can create the target directory --- but then remove it
* because we rely on cp(1) to create it for real.
*/
target_dir = alt_loc ? alt_loc : nominal_loc;
if (mkdir(target_dir, S_IRWXU) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create database directory \"%s\": %m",
target_dir)));
if (rmdir(target_dir) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove temp directory \"%s\": %m",
target_dir)));
/* Make the symlink, if needed */
if (alt_loc)
{
#ifdef HAVE_SYMLINK /* already throws error above */
if (symlink(alt_loc, nominal_loc) != 0)
#endif
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not link \"%s\" to \"%s\": %m",
nominal_loc, alt_loc)));
}
/*
* Copy the template database 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.
*/
#ifndef WIN32
snprintf(buf, sizeof(buf), "cp -r '%s' '%s'", src_loc, target_dir);
if (system(buf) != 0)
{
if (remove_dbdirs(nominal_loc, alt_loc))
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
ereport(ERROR,
(errmsg("could not initialize database directory; delete failed as well"),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
}
#else /* WIN32 */
if (copydir(src_loc, target_dir) != 0)
{
/* copydir should already have given details of its troubles */
if (remove_dbdirs(nominal_loc, alt_loc))
ereport(ERROR,
(errmsg("could not initialize database directory")));
else
ereport(ERROR,
(errmsg("could not initialize database directory; delete failed as well")));
}
#endif /* WIN32 */
/*
* Now OK to grab exclusive lock on pg_database.
*/
pg_database_rel = heap_openr(DatabaseRelationName, AccessExclusiveLock);
/* Check to see if someone else created same DB name meanwhile. */
if (get_db_info(dbname, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL))
{
/* Don't hold lock while doing recursive remove */
heap_close(pg_database_rel, AccessExclusiveLock);
remove_dbdirs(nominal_loc, alt_loc);
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] = Int32GetDatum(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);
/* do not set datpath to null, GetRawDatabaseInfo won't cope */
new_record[Anum_pg_database_datpath - 1] =
DirectFunctionCall1(textin, CStringGetDatum(dbpath ? dbpath : ""));
/*
* 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 lock till commit */
heap_close(pg_database_rel, NoLock);
/*
* Force dirty buffers out to disk, so that newly-connecting backends
* will see the new database in pg_database right away. (They'll see
* an uncommitted tuple, but they don't care; see GetRawDatabaseInfo.)
*/
BufferSync();
}
/*
* DROP DATABASE
*/
void
dropdb(const char *dbname)
{
int4 db_owner;
bool db_istemplate;
Oid db_id;
char *alt_loc;
char *nominal_loc;
char dbpath[MAXPGPATH];
Relation pgdbrel;
SysScanDesc pgdbscan;
ScanKeyData key;
HeapTuple tup;
AssertArg(dbname);
if (strcmp(dbname, get_database_name(MyDatabaseId)) == 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot drop the currently open database")));
PreventTransactionChain((void *) dbname, "DROP 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 will read pg_database without any locking to
* discover the database's OID. But it will detect its error in
* ReverifyMyDatabase and shut down before any serious damage is done.
* See postinit.c.)
*/
pgdbrel = heap_openr(DatabaseRelationName, AccessExclusiveLock);
if (!get_db_info(dbname, &db_id, &db_owner, NULL,
&db_istemplate, NULL, NULL, NULL, dbpath))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
if (GetUserId() != db_owner && !superuser())
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")));
nominal_loc = GetDatabasePath(db_id);
alt_loc = resolve_alt_dbpath(dbpath, db_id);
/*
* 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).
*/
ScanKeyEntryInitialize(&key, 0, ObjectIdAttributeNumber,
F_OIDEQ, ObjectIdGetDatum(db_id));
pgdbscan = systable_beginscan(pgdbrel, DatabaseOidIndex, 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, RelationGetRelid(pgdbrel), 0);
/*
* Close pg_database, but keep exclusive lock till commit to ensure
* that any new backend scanning pg_database will see the tuple dead.
*/
heap_close(pgdbrel, NoLock);
/*
* 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);
/*
* Remove the database's subdirectory and everything in it.
*/
remove_dbdirs(nominal_loc, alt_loc);
/*
* Force dirty buffers out to disk, so that newly-connecting backends
* will see the database tuple marked dead in pg_database right away.
* (They'll see an uncommitted deletion, but they don't care; see
* GetRawDatabaseInfo.)
*/
BufferSync();
}
/*
* Rename database
*/
void
RenameDatabase(const char *oldname, const char *newname)
{
HeapTuple tup,
newtup;
Relation rel;
SysScanDesc scan,
scan2;
ScanKeyData key,
key2;
/*
* Obtain AccessExclusiveLock so that no new session gets started
* while the rename is in progress.
*/
rel = heap_openr(DatabaseRelationName, AccessExclusiveLock);
ScanKeyEntryInitialize(&key, 0, Anum_pg_database_datname,
F_NAMEEQ, NameGetDatum(oldname));
scan = systable_beginscan(rel, DatabaseNameIndex, 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 */
ScanKeyEntryInitialize(&key2, 0, Anum_pg_database_datname,
F_NAMEEQ, NameGetDatum(newname));
scan2 = systable_beginscan(rel, DatabaseNameIndex, 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 */
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, &tup->t_self, newtup);
CatalogUpdateIndexes(rel, newtup);
systable_endscan(scan);
heap_close(rel, NoLock);
/*
* Force dirty buffers out to disk, so that newly-connecting backends
* will see the renamed database in pg_database right away. (They'll
* see an uncommitted tuple, but they don't care; see
* GetRawDatabaseInfo.)
*/
BufferSync();
}
/*
* 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);
rel = heap_openr(DatabaseRelationName, RowExclusiveLock);
ScanKeyEntryInitialize(&scankey, 0, Anum_pg_database_datname,
F_NAMEEQ, NameGetDatum(stmt->dbname));
scan = systable_beginscan(rel, DatabaseNameIndex, 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 (!(superuser()
|| ((Form_pg_database) GETSTRUCT(tuple))->datdba == 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 ? ((ArrayType *) 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, rel, repl_val, repl_null, repl_repl);
simple_heap_update(rel, &tuple->t_self, newtuple);
/* Update indexes */
CatalogUpdateIndexes(rel, newtuple);
systable_endscan(scan);
heap_close(rel, RowExclusiveLock);
}
/*
* Helper functions
*/
static bool
get_db_info(const char *name, Oid *dbIdP, int4 *ownerIdP,
int *encodingP, bool *dbIsTemplateP, Oid *dbLastSysOidP,
TransactionId *dbVacuumXidP, TransactionId *dbFrozenXidP,
char *dbpath)
{
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_openr(DatabaseRelationName, AccessShareLock);
ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname,
F_NAMEEQ, NameGetDatum(name));
scan = systable_beginscan(relation, DatabaseNameIndex, 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);
/* sysid of the owner */
if (ownerIdP)
*ownerIdP = dbform->datdba;
/* character encoding */
if (encodingP)
*encodingP = dbform->encoding;
/* allowed as template? */
if (dbIsTemplateP)
*dbIsTemplateP = dbform->datistemplate;
/* 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;
/* database path (as registered in pg_database) */
if (dbpath)
{
Datum datum;
bool isnull;
datum = heap_getattr(tuple,
Anum_pg_database_datpath,
RelationGetDescr(relation),
&isnull);
if (!isnull)
{
text *pathtext = DatumGetTextP(datum);
int pathlen = VARSIZE(pathtext) - VARHDRSZ;
Assert(pathlen >= 0 && pathlen < MAXPGPATH);
strncpy(dbpath, VARDATA(pathtext), pathlen);
*(dbpath + pathlen) = '\0';
}
else
strcpy(dbpath, "");
}
}
systable_endscan(scan);
heap_close(relation, AccessShareLock);
return gottuple;
}
static bool
have_createdb_privilege(void)
{
HeapTuple utup;
bool retval;
utup = SearchSysCache(SHADOWSYSID,
Int32GetDatum(GetUserId()),
0, 0, 0);
if (!HeapTupleIsValid(utup))
retval = false;
else
retval = ((Form_pg_shadow) GETSTRUCT(utup))->usecreatedb;
ReleaseSysCache(utup);
return retval;
}
static char *
resolve_alt_dbpath(const char *dbpath, Oid dboid)
{
const char *prefix;
char *ret;
size_t len;
if (dbpath == NULL || dbpath[0] == '\0')
return NULL;
if (first_path_separator(dbpath))
{
if (!is_absolute_path(dbpath))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("relative paths are not allowed as database locations")));
#ifndef ALLOW_ABSOLUTE_DBPATHS
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("absolute paths are not allowed as database locations")));
#endif
prefix = dbpath;
}
else
{
/* must be environment variable */
char *var = getenv(dbpath);
if (!var)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("postmaster environment variable \"%s\" not found",
dbpath)));
if (!is_absolute_path(var))
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("postmaster environment variable \"%s\" must be absolute path",
dbpath)));
prefix = var;
}
len = strlen(prefix) + 6 + sizeof(Oid) * 8 + 1;
if (len >= MAXPGPATH - 100)
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("alternate path is too long")));
ret = palloc(len);
snprintf(ret, len, "%s/base/%u", prefix, dboid);
return ret;
}
static bool
remove_dbdirs(const char *nominal_loc, const char *alt_loc)
{
const char *target_dir;
char buf[MAXPGPATH + 100];
bool success = true;
target_dir = alt_loc ? alt_loc : nominal_loc;
/*
* Close virtual file descriptors so the kernel has more available for
* the system() call below.
*/
closeAllVfds();
if (alt_loc)
{
/* remove symlink */
if (unlink(nominal_loc) != 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove \"%s\": %m", nominal_loc)));
success = false;
}
}
#ifndef WIN32
snprintf(buf, sizeof(buf), "rm -rf '%s'", target_dir);
#else
snprintf(buf, sizeof(buf), "rmdir /s /q \"%s\"", target_dir);
#endif
if (system(buf) != 0)
{
ereport(WARNING,
(errmsg("could not remove database directory \"%s\"",
target_dir),
errdetail("Failing system command was: %s", buf),
errhint("Look in the postmaster's stderr log for more information.")));
success = false;
}
return success;
}
/*
* 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_openr(DatabaseRelationName, AccessShareLock);
ScanKeyEntryInitialize(&entry[0], 0x0,
Anum_pg_database_datname, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(pg_database, DatabaseNameIndex, 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 InvalidOid if database name not found.
*
* 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_openr(DatabaseRelationName, AccessShareLock);
ScanKeyEntryInitialize(&entry[0], 0x0,
ObjectIdAttributeNumber, F_OIDEQ,
ObjectIdGetDatum(dbid));
scan = systable_beginscan(pg_database, DatabaseOidIndex, 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;
}
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