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https://github.com/postgres/postgres.git
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664dd614d9
to do it at the last moment before calling system() ... not at some randomly-chosen earlier point in the routine ...
396 lines
10 KiB
C
396 lines
10 KiB
C
/*-------------------------------------------------------------------------
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*
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* dbcommands.c
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*
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/commands/dbcommands.c,v 1.57 2000/06/02 04:04:54 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "commands/dbcommands.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include "access/heapam.h"
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#include "catalog/catname.h"
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#include "catalog/pg_database.h"
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#include "catalog/pg_shadow.h"
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#include "commands/comment.h"
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#include "miscadmin.h"
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#include "storage/sinval.h" /* for DatabaseHasActiveBackends */
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#include "utils/builtins.h"
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#include "utils/fmgroids.h"
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#include "utils/syscache.h"
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/* non-export function prototypes */
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static bool
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get_user_info(const char *name, int4 *use_sysid, bool *use_super, bool *use_createdb);
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static bool
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get_db_info(const char *name, char *dbpath, Oid *dbIdP, int4 *ownerIdP);
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/*
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* CREATE DATABASE
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*/
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void
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createdb(const char *dbname, const char *dbpath, int encoding)
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{
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char buf[2 * MAXPGPATH + 100];
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char *loc;
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char locbuf[512];
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int4 user_id;
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int ret;
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bool use_super,
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use_createdb;
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Relation pg_database_rel;
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HeapTuple tuple;
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TupleDesc pg_database_dsc;
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Datum new_record[Natts_pg_database];
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char new_record_nulls[Natts_pg_database] = {' ', ' ', ' ', ' '};
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if (!get_user_info(GetPgUserName(), &user_id, &use_super, &use_createdb))
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elog(ERROR, "current user name is invalid");
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if (!use_createdb && !use_super)
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elog(ERROR, "CREATE DATABASE: permission denied");
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if (get_db_info(dbname, NULL, NULL, NULL))
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elog(ERROR, "CREATE DATABASE: database \"%s\" already exists", dbname);
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/* don't call this in a transaction block */
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if (IsTransactionBlock())
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elog(ERROR, "CREATE DATABASE: may not be called in a transaction block");
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/* Generate directory name for the new database */
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if (dbpath == NULL || strcmp(dbpath, dbname) == 0)
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strcpy(locbuf, dbname);
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else
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snprintf(locbuf, sizeof(locbuf), "%s/%s", dbpath, dbname);
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loc = ExpandDatabasePath(locbuf);
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if (loc == NULL)
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elog(ERROR,
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"The database path '%s' is invalid. "
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"This may be due to a character that is not allowed or because the chosen "
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"path isn't permitted for databases", dbpath);
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/*
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* Insert a new tuple into pg_database
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*/
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pg_database_rel = heap_openr(DatabaseRelationName, AccessExclusiveLock);
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pg_database_dsc = RelationGetDescr(pg_database_rel);
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/* Form tuple */
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new_record[Anum_pg_database_datname - 1] = NameGetDatum(namein(dbname));
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new_record[Anum_pg_database_datdba - 1] = Int32GetDatum(user_id);
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new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
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new_record[Anum_pg_database_datpath - 1] = PointerGetDatum(textin(locbuf));
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tuple = heap_formtuple(pg_database_dsc, new_record, new_record_nulls);
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/*
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* Update table
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*/
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heap_insert(pg_database_rel, tuple);
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/*
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* Update indexes (there aren't any currently)
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*/
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#ifdef Num_pg_database_indices
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if (RelationGetForm(pg_database_rel)->relhasindex)
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{
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Relation idescs[Num_pg_database_indices];
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CatalogOpenIndices(Num_pg_database_indices,
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Name_pg_database_indices, idescs);
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CatalogIndexInsert(idescs, Num_pg_database_indices, pg_database_rel,
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tuple);
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CatalogCloseIndices(Num_pg_database_indices, idescs);
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}
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#endif
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heap_close(pg_database_rel, NoLock);
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/*
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* Close virtual file descriptors so the kernel has more available for
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* the mkdir() and system() calls below.
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*/
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closeAllVfds();
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/* Copy the template database to the new location */
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if (mkdir(loc, S_IRWXU) != 0)
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elog(ERROR, "CREATE DATABASE: unable to create database directory '%s': %s", loc, strerror(errno));
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snprintf(buf, sizeof(buf), "cp %s%cbase%ctemplate1%c* '%s'",
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DataDir, SEP_CHAR, SEP_CHAR, SEP_CHAR, loc);
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ret = system(buf);
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/* Some versions of SunOS seem to return ECHILD after a system() call */
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#if defined(sun)
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if (ret != 0 && errno != ECHILD)
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#else
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if (ret != 0)
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#endif
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{
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/* Failed, so try to clean up the created directory ... */
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snprintf(buf, sizeof(buf), "rm -rf '%s'", loc);
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ret = system(buf);
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#if defined(sun)
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if (ret == 0 || errno == ECHILD)
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#else
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if (ret == 0)
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#endif
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elog(ERROR, "CREATE DATABASE: could not initialize database directory");
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else
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elog(ERROR, "CREATE DATABASE: Could not initialize database directory. Delete failed as well");
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}
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}
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/*
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* DROP DATABASE
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*/
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void
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dropdb(const char *dbname)
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{
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int4 user_id,
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db_owner;
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bool use_super;
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Oid db_id;
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char *path,
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dbpath[MAXPGPATH],
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buf[MAXPGPATH + 100];
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Relation pgdbrel;
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HeapScanDesc pgdbscan;
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ScanKeyData key;
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HeapTuple tup;
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AssertArg(dbname);
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if (strcmp(dbname, "template1") == 0)
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elog(ERROR, "DROP DATABASE: May not be executed on the template1 database");
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if (strcmp(dbname, DatabaseName) == 0)
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elog(ERROR, "DROP DATABASE: Cannot be executed on the currently open database");
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if (IsTransactionBlock())
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elog(ERROR, "DROP DATABASE: May not be called in a transaction block");
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if (!get_user_info(GetPgUserName(), &user_id, &use_super, NULL))
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elog(ERROR, "Current user name is invalid");
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if (!get_db_info(dbname, dbpath, &db_id, &db_owner))
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elog(ERROR, "DROP DATABASE: Database \"%s\" does not exist", dbname);
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if (user_id != db_owner && !use_super)
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elog(ERROR, "DROP DATABASE: Permission denied");
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path = ExpandDatabasePath(dbpath);
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if (path == NULL)
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elog(ERROR,
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"The database path '%s' is invalid. "
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"This may be due to a character that is not allowed or because the chosen "
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"path isn't permitted for databases", path);
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/*
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* Obtain exclusive lock on pg_database. We need this to ensure that
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* no new backend starts up in the target database while we are
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* deleting it. (Actually, a new backend might still manage to start
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* up, because it will read pg_database without any locking to
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* discover the database's OID. But it will detect its error in
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* ReverifyMyDatabase and shut down before any serious damage is done.
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* See postinit.c.)
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*/
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pgdbrel = heap_openr(DatabaseRelationName, AccessExclusiveLock);
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/*
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* Check for active backends in the target database.
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*/
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if (DatabaseHasActiveBackends(db_id))
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{
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heap_close(pgdbrel, AccessExclusiveLock);
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elog(ERROR, "DROP DATABASE: Database \"%s\" is being accessed by other users", dbname);
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}
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/*
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* Find the database's tuple by OID (should be unique, we trust).
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*/
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ScanKeyEntryInitialize(&key, 0, ObjectIdAttributeNumber,
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F_OIDEQ, ObjectIdGetDatum(db_id));
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pgdbscan = heap_beginscan(pgdbrel, 0, SnapshotNow, 1, &key);
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tup = heap_getnext(pgdbscan, 0);
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if (!HeapTupleIsValid(tup))
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{
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heap_close(pgdbrel, AccessExclusiveLock);
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/*
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* This error should never come up since the existence of the
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* database is checked earlier
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*/
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elog(ERROR, "DROP DATABASE: Database \"%s\" doesn't exist despite earlier reports to the contrary",
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dbname);
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}
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/* Delete any comments associated with the database */
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DeleteComments(db_id);
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/* Remove the database's tuple from pg_database */
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heap_delete(pgdbrel, &tup->t_self, NULL);
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heap_endscan(pgdbscan);
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/*
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* Close pg_database, but keep exclusive lock till commit to ensure
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* that any new backend scanning pg_database will see the tuple dead.
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*/
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heap_close(pgdbrel, NoLock);
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/*
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* Drop pages for this database that are in the shared buffer cache.
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* This is important to ensure that no remaining backend tries to
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* write out a dirty buffer to the dead database later...
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*/
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DropBuffers(db_id);
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/*
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* Close virtual file descriptors so the kernel has more available for
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* the system() call below.
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*/
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closeAllVfds();
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/*
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* Remove the database's subdirectory and everything in it.
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*/
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snprintf(buf, sizeof(buf), "rm -rf '%s'", path);
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#if defined(sun)
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if (system(buf) != 0 && errno != ECHILD)
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#else
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if (system(buf) != 0)
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#endif
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elog(NOTICE, "DROP DATABASE: The database directory '%s' could not be removed", path);
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}
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/*
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* Helper functions
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*/
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static bool
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get_db_info(const char *name, char *dbpath, Oid *dbIdP, int4 *ownerIdP)
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{
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Relation relation;
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HeapTuple tuple;
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ScanKeyData scanKey;
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HeapScanDesc scan;
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AssertArg(name);
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relation = heap_openr(DatabaseRelationName, AccessExclusiveLock /* ??? */ );
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ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname,
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F_NAMEEQ, NameGetDatum(name));
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scan = heap_beginscan(relation, 0, SnapshotNow, 1, &scanKey);
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if (!HeapScanIsValid(scan))
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elog(ERROR, "Cannot begin scan of %s.", DatabaseRelationName);
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tuple = heap_getnext(scan, 0);
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if (HeapTupleIsValid(tuple))
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{
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text *tmptext;
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bool isnull;
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/* oid of the database */
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if (dbIdP)
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*dbIdP = tuple->t_data->t_oid;
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/* uid of the owner */
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if (ownerIdP)
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{
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*ownerIdP = (int4) heap_getattr(tuple,
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Anum_pg_database_datdba,
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RelationGetDescr(relation),
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&isnull);
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if (isnull)
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*ownerIdP = -1; /* hopefully no one has that id already ;) */
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}
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/* database path (as registered in pg_database) */
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if (dbpath)
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{
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tmptext = (text *) heap_getattr(tuple,
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Anum_pg_database_datpath,
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RelationGetDescr(relation),
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&isnull);
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if (!isnull)
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{
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Assert(VARSIZE(tmptext) - VARHDRSZ < MAXPGPATH);
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strncpy(dbpath, VARDATA(tmptext), VARSIZE(tmptext) - VARHDRSZ);
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*(dbpath + VARSIZE(tmptext) - VARHDRSZ) = '\0';
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}
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else
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strcpy(dbpath, "");
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}
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}
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else
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{
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if (dbIdP)
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*dbIdP = InvalidOid;
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}
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heap_endscan(scan);
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/* We will keep the lock on the relation until end of transaction. */
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heap_close(relation, NoLock);
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return HeapTupleIsValid(tuple);
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}
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static bool
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get_user_info(const char *name, int4 *use_sysid, bool *use_super, bool *use_createdb)
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{
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HeapTuple utup;
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AssertArg(name);
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utup = SearchSysCacheTuple(SHADOWNAME,
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PointerGetDatum(name),
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0, 0, 0);
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if (!HeapTupleIsValid(utup))
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return false;
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if (use_sysid)
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*use_sysid = ((Form_pg_shadow) GETSTRUCT(utup))->usesysid;
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if (use_super)
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*use_super = ((Form_pg_shadow) GETSTRUCT(utup))->usesuper;
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if (use_createdb)
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*use_createdb = ((Form_pg_shadow) GETSTRUCT(utup))->usecreatedb;
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return true;
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}
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