db_open.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2002
 *	Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: db_open.c,v 11.215 2002/08/15 15:27:52 bostic Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/db_shash.h"
#include "dbinc/db_swap.h"
#include "dbinc/btree.h"
#include "dbinc/crypto.h"
#include "dbinc/hmac.h"
#include "dbinc/fop.h"
#include "dbinc/hash.h"
#include "dbinc/lock.h"
#include "dbinc/log.h"
#include "dbinc/qam.h"
#include "dbinc/txn.h"

static int __db_openchk __P((DB *,
    DB_TXN *, const char *, const char *, DBTYPE, u_int32_t));

/*
 * __db_open --
 *	Main library interface to the DB access methods.
 *
 * PUBLIC: int __db_open __P((DB *, DB_TXN *,
 * PUBLIC:     const char *, const char *, DBTYPE, u_int32_t, int));
 */
int
__db_open(dbp, txn, name, subdb, type, flags, mode)
	DB *dbp;
	DB_TXN *txn;
	const char *name, *subdb;
	DBTYPE type;
	u_int32_t flags;
	int mode;
{
	DB_ENV *dbenv;
	int remove_master, remove_me, ret, t_ret, txn_local;

	dbenv = dbp->dbenv;
	remove_me = remove_master = txn_local = 0;

	PANIC_CHECK(dbenv);

	if ((ret = __db_openchk(dbp, txn, name, subdb, type, flags)) != 0)
		return (ret);

	/*
	 * Create local transaction as necessary, check for consistent
	 * transaction usage.
	 */
	if (IS_AUTO_COMMIT(dbenv, txn, flags)) {
		if ((ret = __db_txn_auto(dbp, &txn)) != 0)
			return (ret);
		txn_local = 1;
	} else
		if (txn != NULL && !TXN_ON(dbenv))
			return (__db_not_txn_env(dbenv));

	/*
	 * If the environment was configured with threads, the DB handle
	 * must also be free-threaded, so we force the DB_THREAD flag on.
	 * (See SR #2033 for why this is a requirement--recovery needs
	 * to be able to grab a dbp using __db_fileid_to_dbp, and it has
	 * no way of knowing which dbp goes with which thread, so whichever
	 * one it finds has to be usable in any of them.)
	 */
	if (F_ISSET(dbenv, DB_ENV_THREAD))
		LF_SET(DB_THREAD);

	/* Convert any DB->open flags. */
	if (LF_ISSET(DB_RDONLY))
		F_SET(dbp, DB_AM_RDONLY);
	if (LF_ISSET(DB_DIRTY_READ))
		F_SET(dbp, DB_AM_DIRTY);

	/* Fill in the type. */
	dbp->type = type;

	/*
	 * If we're opening a subdatabase, we have to open (and potentially
	 * create) the main database, and then get (and potentially store)
	 * our base page number in that database.  Then, we can finally open
	 * the subdatabase.
	 */
	if ((ret = __db_dbopen(
	    dbp, txn, name, subdb, flags, mode, PGNO_BASE_MD)) != 0)
		goto err;

	/*
	 * You can open the database that describes the subdatabases in the
	 * rest of the file read-only.  The content of each key's data is
	 * unspecified and applications should never be adding new records
	 * or updating existing records.  However, during recovery, we need
	 * to open these databases R/W so we can redo/undo changes in them.
	 * Likewise, we need to open master databases read/write during
	 * rename and remove so we can be sure they're fully sync'ed, so
	 * we provide an override flag for the purpose.
	 */
	if (subdb == NULL && !IS_RECOVERING(dbenv) && !LF_ISSET(DB_RDONLY) &&
	    !LF_ISSET(DB_RDWRMASTER) && F_ISSET(dbp, DB_AM_SUBDB)) {
		__db_err(dbenv,
    "files containing multiple databases may only be opened read-only");
		ret = EINVAL;
		goto err;
	}

err:	/* If we were successful, don't discard the file on close. */
	if (ret == 0)
		/* If we were successful, don't discard the file on close. */
		F_CLR(dbp, DB_AM_DISCARD | DB_AM_CREATED | DB_AM_CREATED_MSTR);
	else {
		/*
		 * If we are not transactional, we need to remove the
		 * databases/subdatabases.  If we are transactional, then
		 * the abort of the child transaction should take care of
		 * cleaning them up.
		 */
		remove_me = txn == NULL && F_ISSET(dbp, DB_AM_CREATED);
		remove_master = txn == NULL && F_ISSET(dbp, DB_AM_CREATED_MSTR);

		/*
		 * If we had an error, it may have happened before or after
		 * we actually logged the open.  If it happened before, then
		 * abort won't know anything about it and won't close or
		 * refresh the dbp, so we need to do it explicitly.
		 */
		(void)__db_refresh(dbp, txn, DB_NOSYNC);
	}

	/* Remove anyone we created. */
	if (remove_master || (subdb == NULL && remove_me))
		/* Remove file. */
		(void)dbenv->dbremove(dbenv, txn, name, NULL, 0);
	else if (remove_me)
		/* Remove subdatabase. */
		(void)dbenv->dbremove(dbenv, txn, name, subdb, 0);

	/* Commit for DB_AUTO_COMMIT. */
	if (txn_local) {
		if (ret == 0)
			ret = txn->commit(txn, 0);
		else
			if ((t_ret = txn->abort(txn)) != 0)
				ret = __db_panic(dbenv, t_ret);
	}

	return (ret);
}

/*
 * __db_dbopen --
 *	Open a database.  This routine  gets called in three different ways.
 * 1. It can be called to open a file/database.  In this case, subdb will
 *    be NULL and meta_pgno will be PGNO_BASE_MD.
 * 2. It can be called to open a subdatabase during normal operation.  In
 *    this case, name and subname will both be non-NULL and meta_pgno will
 *    be PGNO_BAS_MD (also PGNO_INVALID).
 * 3. It can be called during recovery to open a subdatabase in which case
 *    name will be non-NULL, subname mqy be NULL and meta-pgno will be
 *    a valid pgno (i.e., not PGNO_BASE_MD).
 *
 * PUBLIC: int __db_dbopen __P((DB *, DB_TXN *,
 * PUBLIC:     const char *, const char *, u_int32_t, int, db_pgno_t));
 */
int
__db_dbopen(dbp, txn, name, subdb, flags, mode, meta_pgno)
	DB *dbp;
	DB_TXN *txn;
	const char *name, *subdb;
	u_int32_t flags;
	int mode;
	db_pgno_t meta_pgno;
{
	DB_ENV *dbenv;
	int ret;
	u_int32_t id;

	dbenv = dbp->dbenv;
	id = TXN_INVALID;
	if (txn != NULL)
		F_SET(dbp, DB_AM_TXN);

	DB_TEST_RECOVERY(dbp, DB_TEST_PREOPEN, ret, name);
	/*
	 * If name is NULL, it's always a create, so make sure that we
	 * have a type specified.  It would be nice if this checking
	 * were done in __db_open where most of the interface checking
	 * is done, but this interface (__db_dbopen) is used by the
	 * recovery and limbo system, so we need to safeguard this
	 * interface as well.
	 */
	if (name == NULL) {
		F_SET(dbp, DB_AM_INMEM);

		if (dbp->type == DB_UNKNOWN) {
			__db_err(dbenv,
			    "DBTYPE of unknown without existing file");
			return (EINVAL);
		}

		if (dbp->pgsize == 0)
			dbp->pgsize = DB_DEF_IOSIZE;

		/*
		 * If the file is a temporary file and we're doing locking,
		 * then we have to create a unique file ID.  We can't use our
		 * normal dev/inode pair (or whatever this OS uses in place of
		 * dev/inode pairs) because no backing file will be created
		 * until the mpool cache is filled forcing the buffers to disk.
		 * Grab a random locker ID to use as a file ID.  The created
		 * ID must never match a potential real file ID -- we know it
		 * won't because real file IDs contain a time stamp after the
		 * dev/inode pair, and we're simply storing a 4-byte value.
		 *
		 * !!!
		 * Store the locker in the file id structure -- we can get it
		 * from there as necessary, and it saves having two copies.
		 */
		if (LOCKING_ON(dbenv) && (ret = dbenv->lock_id(dbenv,
		    (u_int32_t *)dbp->fileid)) != 0)
			return (ret);
	} else if (subdb == NULL && meta_pgno == PGNO_BASE_MD) {
		/* Open/create the underlying file.  Acquire locks. */
		if ((ret =
		    __fop_file_setup(dbp, txn, name, mode, flags, &id)) != 0)
			return (ret);
	} else {
		if ((ret = __fop_subdb_setup(dbp,
		    txn, name, subdb, mode, flags)) != 0)
			return (ret);
		meta_pgno = dbp->meta_pgno;
	}

	/*
	 * If we created the file, set the truncate flag for the mpool.  This
	 * isn't for anything we've done, it's protection against stupid user
	 * tricks: if the user deleted a file behind Berkeley DB's back, we
	 * may still have pages in the mpool that match the file's "unique" ID.
	 *
	 * Note that if we're opening a subdatabase, we don't want to set
	 * the TRUNCATE flag even if we just created the file--we already
	 * opened and updated the master using access method interfaces,
	 * so we don't want to get rid of any pages that are in the mpool.
	 * If we created the file when we opened the master, we already hit
	 * this check in a non-subdb context then.
	 */
	if (subdb == NULL && F_ISSET(dbp, DB_AM_CREATED))
		LF_SET(DB_TRUNCATE);

	/* Set up the underlying environment. */
	if ((ret = __db_dbenv_setup(dbp, txn, name, id, flags)) != 0)
		return (ret);

	/*
	 * Set the open flag.  We use it to mean that the dbp has gone
	 * through mpf setup, including dbreg_register.  Also, below,
	 * the underlying access method open functions may want to do
	 * things like acquire cursors, so the open flag has to be set
	 * before calling them.
	 */
	F_SET(dbp, DB_AM_OPEN_CALLED);

	/*
	 * For unnamed files, we need to actually create the file now
	 * that the mpool is open.
	 */
	if (name == NULL && (ret = __db_new_file(dbp, txn, NULL, NULL)) != 0)
		return (ret);

	switch (dbp->type) {
	case DB_BTREE:
		ret = __bam_open(dbp, txn, name, meta_pgno, flags);
		break;
	case DB_HASH:
		ret = __ham_open(dbp, txn, name, meta_pgno, flags);
		break;
	case DB_RECNO:
		ret = __ram_open(dbp, txn, name, meta_pgno, flags);
		break;
	case DB_QUEUE:
		ret = __qam_open(dbp, txn, name, meta_pgno, mode, flags);
		break;
	case DB_UNKNOWN:
		return (__db_unknown_type(dbenv, "__db_dbopen", dbp->type));
	}
	if (ret != 0)
		goto err;

	DB_TEST_RECOVERY(dbp, DB_TEST_POSTOPEN, ret, name);

	/*
	 * Unnamed files don't need handle locks, so we only have to check
	 * for a handle lock downgrade or lockevent in the case of named
	 * files.
	 */
	if (!F_ISSET(dbp, DB_AM_RECOVER) &&
	    name != NULL && LOCK_ISSET(dbp->handle_lock)) {
		if (txn != NULL) {
			ret = __txn_lockevent(dbenv,
			    txn, dbp, &dbp->handle_lock, dbp->lid);
		} else if (LOCKING_ON(dbenv))
			/* Trade write handle lock for read handle lock. */
			ret = __lock_downgrade(dbenv,
			    &dbp->handle_lock, DB_LOCK_READ, 0);
	}
DB_TEST_RECOVERY_LABEL
err:
	return (ret);
}

/*
 * __db_new_file --
 *	Create a new database file.
 *
 * PUBLIC: int __db_new_file __P((DB *, DB_TXN *, DB_FH *, const char *));
 */
int
__db_new_file(dbp, txn, fhp, name)
	DB *dbp;
	DB_TXN *txn;
	DB_FH *fhp;
	const char *name;
{
	int ret;

	switch (dbp->type) {
	case DB_BTREE:
	case DB_RECNO:
		ret = __bam_new_file(dbp, txn, fhp, name);
		break;
	case DB_HASH:
		ret = __ham_new_file(dbp, txn, fhp, name);
		break;