/*------------------------------------------------------------------------- * * database.c-- * miscellanious initialization support stuff * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/utils/misc/Attic/database.c,v 1.18 1998/09/01 03:26:58 momjian Exp $ * *------------------------------------------------------------------------- */ #include #include #include #include #include #include "postgres.h" #include "access/heapam.h" #include "access/xact.h" #include "catalog/catname.h" #include "catalog/pg_database.h" #include "fmgr.h" #include "miscadmin.h" #include "storage/bufmgr.h" #include "storage/bufpage.h" #include "utils/builtins.h" #include "utils/syscache.h" #ifdef MULTIBYTE #include "mb/pg_wchar.h" #endif #ifdef 0 /* GetDatabaseInfo() * Pull database information from pg_database. */ int GetDatabaseInfo(char *name, int4 *owner, char *path) { Oid dbowner, dbid; char dbpath[MAXPGPATH + 1]; text *dbtext; Relation dbrel; HeapTuple dbtup; HeapTuple tup; HeapScanDesc scan; ScanKeyData scanKey; dbrel = heap_openr(DatabaseRelationName); if (!RelationIsValid(dbrel)) elog(FATAL, "GetDatabaseInfo: cannot open relation \"%-.*s\"", DatabaseRelationName); ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname, F_NAMEEQ, NameGetDatum(name)); scan = heap_beginscan(dbrel, 0, SnapshotNow, 1, &scanKey); if (!HeapScanIsValid(scan)) elog(ERROR, "GetDatabaseInfo: cannot begin scan of %s", DatabaseRelationName); /* * Since we're going to close the relation, copy the tuple. */ tup = heap_getnext(scan, 0); if (HeapTupleIsValid(tup)) dbtup = heap_copytuple(tup); else dbtup = tup; heap_endscan(scan); if (!HeapTupleIsValid(dbtup)) { elog(NOTICE, "GetDatabaseInfo: %s entry not found %s", DatabaseRelationName, name); return TRUE; } dbowner = (Oid) heap_getattr(dbtup, Anum_pg_database_datdba, RelationGetDescr(dbrel), (char *) NULL); dbid = dbtup->t_oid; dbtext = (text *) heap_getattr(dbtup, Anum_pg_database_datpath, RelationGetDescr(dbrel), (char *) NULL); memcpy(dbpath, VARDATA(dbtext), (VARSIZE(dbtext) - VARHDRSZ)); *(dbpath + (VARSIZE(dbtext) - VARHDRSZ)) = '\0'; heap_close(dbrel); owner = palloc(sizeof(Oid)); *owner = dbowner; path = palloc(strlen(dbpath) + 1); strcpy(path, dbpath); return FALSE; } /* GetDatabaseInfo() */ #endif char * ExpandDatabasePath(char *dbpath) { char *path; char *cp; char buf[MAXPGPATH + 1]; /* leading path delimiter? then already absolute path */ if (*dbpath == SEP_CHAR) { #ifdef ALLOW_ABSOLUTE_DBPATHS cp = strrchr(dbpath, SEP_CHAR); strncpy(buf, dbpath, (cp - dbpath)); sprintf(&buf[cp - dbpath], "%cbase%c%s", SEP_CHAR, SEP_CHAR, (cp + 1)); #else return NULL; #endif } /* path delimiter somewhere? then has leading environment variable */ else if (strchr(dbpath, SEP_CHAR) != NULL) { cp = strchr(dbpath, SEP_CHAR); strncpy(buf, dbpath, (cp - dbpath)); buf[cp - dbpath] = '\0'; path = getenv(buf); /* * problem getting environment variable? let calling routine * handle it */ if (path == NULL) return path; sprintf(buf, "%s%cbase%c%s", path, SEP_CHAR, SEP_CHAR, (cp + 1)); } /* no path delimiter? then add the default path prefixes */ else sprintf(buf, "%s%cbase%c%s", DataDir, SEP_CHAR, SEP_CHAR, dbpath); path = palloc(strlen(buf) + 1); strcpy(path, buf); return path; } /* ExpandDatabasePath() */ /* -------------------------------- * GetRawDatabaseInfo() -- Find the OID and path of the database. * * The database's oid forms half of the unique key for the system * caches and lock tables. We therefore want it initialized before * we open any relations, since opening relations puts things in the * cache. To get around this problem, this code opens and scans the * pg_database relation by hand. * * This algorithm relies on the fact that first attribute in the * pg_database relation schema is the database name. It also knows * about the internal format of tuples on disk and the length of * the datname attribute. It knows the location of the pg_database * file. * Actually, the code looks as though it is using the pg_database * tuple definition to locate the database name, so the above statement * seems to be no longer correct. - thomas 1997-11-01 * * This code is called from InitPostgres(), before we chdir() to the * local database directory and before we open any relations. * Used to be called after the chdir(), but we now want to confirm * the location of the target database using pg_database info. * - thomas 1997-11-01 * -------------------------------- */ void GetRawDatabaseInfo(char *name, int4 *owner, Oid *db_id, char *path, int *encoding) { int dbfd; int fileflags; int nbytes; int max, i; HeapTuple tup; Page pg; PageHeader ph; char *dbfname; Form_pg_database tup_db; dbfname = (char *) palloc(strlen(DataDir) + strlen("pg_database") + 2); sprintf(dbfname, "%s%cpg_database", DataDir, SEP_CHAR); fileflags = O_RDONLY; if ((dbfd = open(dbfname, O_RDONLY, 0)) < 0) elog(FATAL, "Cannot open %s", dbfname); pfree(dbfname); /* ---------------- * read and examine every page in pg_database * * Raw I/O! Read those tuples the hard way! Yow! * * Why don't we use the access methods or move this code * someplace else? This is really pg_database schema dependent * code. Perhaps it should go in lib/catalog/pg_database? * -cim 10/3/90 * * mao replies 4 apr 91: yeah, maybe this should be moved to * lib/catalog. however, we CANNOT use the access methods since * those use the buffer cache, which uses the relation cache, which * requires that the dbid be set, which is what we're trying to do * here. * ---------------- */ pg = (Page) palloc(BLCKSZ); ph = (PageHeader) pg; while ((nbytes = read(dbfd, pg, BLCKSZ)) == BLCKSZ) { max = PageGetMaxOffsetNumber(pg); /* look at each tuple on the page */ for (i = 0; i <= max; i++) { int offset; /* if it's a freed tuple, ignore it */ if (!(ph->pd_linp[i].lp_flags & LP_USED)) continue; /* get a pointer to the tuple itself */ offset = (int) ph->pd_linp[i].lp_off; tup = (HeapTuple) (((char *) pg) + offset); /* * if the tuple has been deleted (the database was destroyed), * skip this tuple. XXX warning, will robinson: violation of * transaction semantics happens right here. we should check * to be sure that the xact that deleted this tuple actually * committed. only way to do this at init time is to paw over * the log relation by hand, too. let's be optimistic. * * XXX This is an evil type cast. tup->t_xmax is char[5] while * TransactionId is struct * { char data[5] }. It works but * if data is ever moved and no longer the first field this * will be broken!! -mer 11 Nov 1991. */ if (TransactionIdIsValid((TransactionId) tup->t_xmax)) continue; /* * Okay, see if this is the one we want. XXX 1 july 91: mao * and mer discover that tuples now squash t_bits. Why is * this? * * 24 july 92: mer realizes that the t_bits field is only used * in the event of null values. If no fields are null we * reduce the header size by doing the squash. t_hoff tells * you exactly how big the header actually is. use the PC * means of getting at sys cat attrs. */ tup_db = (Form_pg_database) GETSTRUCT(tup); #ifdef MULTIBYTE /* get encoding from template database. This is the "default for default" for create database command. */ if (strcmp("template1",tup_db->datname.data) == 0) { SetTemplateEncoding(tup_db->encoding); } #endif if (strcmp(name, tup_db->datname.data) == 0) { *db_id = tup->t_oid; strncpy(path, VARDATA(&(tup_db->datpath)), (VARSIZE(&(tup_db->datpath)) - VARHDRSZ)); *(path + VARSIZE(&(tup_db->datpath)) - VARHDRSZ) = '\0'; #ifdef MULTIBYTE *encoding = tup_db->encoding; #endif goto done; } } } done: close(dbfd); pfree(pg); } /* GetRawDatabaseInfo() */