fop_util.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) 2001-2002
 *	Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: fop_util.c,v 1.52 2002/09/10 02:41:42 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_am.h"
#include "dbinc/fop.h"
#include "dbinc/lock.h"
#include "dbinc/log.h"
#include "dbinc/txn.h"

static int __fop_set_pgsize __P((DB *, DB_FH *, const char *));

/*
 * Acquire the environment meta-data lock.  The parameters are the
 * environment (ENV), the locker id to use in acquiring the lock (ID)
 * and a pointer to a DB_LOCK.
 */
#define	GET_ENVLOCK(ENV, ID, L) do {					\
	DBT __dbt;							\
	u_int32_t __lockval;						\
									\
	if (LOCKING_ON((ENV))) {					\
		__lockval = 0;						\
		__dbt.data = &__lockval;				\
		__dbt.size = sizeof(__lockval);				\
		if ((ret = (ENV)->lock_get((ENV), (ID),			\
		    0, &__dbt, DB_LOCK_WRITE, (L))) != 0)		\
			goto err;					\
	}								\
} while (0)

#define	REL_ENVLOCK(ENV, L)						\
	(!LOCK_ISSET(*(L)) ? 0 : (ENV)->lock_put((ENV), (L)))

/*
 * If our caller is doing fcntl(2) locking, then we can't close it
 * because that would discard the caller's lock.  Otherwise, close
 * the handle.
 */
#define	CLOSE_HANDLE(D, F) {						\
	if (F_ISSET((F), DB_FH_VALID)) {				\
		if (LF_ISSET(DB_FCNTL_LOCKING))				\
			(D)->saved_open_fhp = (F);			\
		else if ((ret = __os_closehandle((D)->dbenv,(F))) != 0)	\
			goto err;					\
	}								\
}

/*
 * __fop_lock_handle --
 *
 * Get the handle lock for a database.  If the envlock is specified,
 * do this as a lock_vec call that releases the enviroment lock before
 * acquiring the handle lock.
 *
 * PUBLIC: int __fop_lock_handle __P((DB_ENV *,
 * PUBLIC:     DB *, u_int32_t, db_lockmode_t, DB_LOCK *, u_int32_t));
 *
 */
int
__fop_lock_handle(dbenv, dbp, locker, mode, elock, flags)
	DB_ENV *dbenv;
	DB *dbp;
	u_int32_t locker;
	db_lockmode_t mode;
	DB_LOCK *elock;
	u_int32_t flags;
{
	DBT fileobj;
	DB_LOCKREQ reqs[2], *ereq;
	DB_LOCK_ILOCK lock_desc;
	int ret;

	if (!LOCKING_ON(dbenv) || F_ISSET(dbp, DB_AM_COMPENSATE))
		return (0);

	/*
	 * If we are in recovery, the only locking we should be
	 * doing is on the global environment.
	 */
	if (IS_RECOVERING(dbenv)) {
		if (elock != NULL)
			REL_ENVLOCK(dbenv, elock);
		return (0);
	}

	memcpy(&lock_desc.fileid, &dbp->fileid, DB_FILE_ID_LEN);
	lock_desc.pgno = dbp->meta_pgno;
	lock_desc.type = DB_HANDLE_LOCK;

	memset(&fileobj, 0, sizeof(fileobj));
	fileobj.data = &lock_desc;
	fileobj.size = sizeof(lock_desc);
	DB_TEST_SUBLOCKS(dbenv, flags);
	if (elock == NULL)
		ret = dbenv->lock_get(dbenv, locker,
		    flags, &fileobj, mode, &dbp->handle_lock);
	else {
		reqs[0].op = DB_LOCK_PUT;
		reqs[0].lock = *elock;
		reqs[1].op = DB_LOCK_GET;
		reqs[1].mode = mode;
		reqs[1].obj = &fileobj;
		reqs[1].timeout = 0;
		if ((ret = __lock_vec(dbenv,
		    locker, flags, reqs, 2, &ereq)) == 0) {
			dbp->handle_lock = reqs[1].lock;
			LOCK_INIT(*elock);
		} else if (ereq != reqs)
			LOCK_INIT(*elock);
	}

	dbp->cur_lid = locker;
	return (ret);
}

/*
 * __fop_file_setup --
 *
 * Perform all the needed checking and locking to open up or create a
 * file.
 *
 * There's a reason we don't push this code down into the buffer cache.
 * The problem is that there's no information external to the file that
 * we can use as a unique ID.  UNIX has dev/inode pairs, but they are
 * not necessarily unique after reboot, if the file was mounted via NFS.
 * Windows has similar problems, as the FAT filesystem doesn't maintain
 * dev/inode numbers across reboot.  So, we must get something from the
 * file we can use to ensure that, even after a reboot, the file we're
 * joining in the cache is the right file for us to join.  The solution
 * we use is to maintain a file ID that's stored in the database, and
 * that's why we have to open and read the file before calling into the
 * buffer cache or obtaining a lock (we use this unique fileid to lock
 * as well as to identify like files in the cache).
 *
 * PUBLIC: int __fop_file_setup __P((DB *,
 * PUBLIC:     DB_TXN *, const char *, int, u_int32_t, u_int32_t *));
 */
int
__fop_file_setup(dbp, txn, name, mode, flags, retidp)
	DB *dbp;
	DB_TXN *txn;
	const char *name;
	int mode;
	u_int32_t flags, *retidp;
{
	DB_ENV *dbenv;
	DB_FH fh, *fhp;
	DB_LOCK elock, tmp_lock;
	DB_TXN *stxn;
	db_lockmode_t lmode;
	u_int32_t locker, oflags;
	u_int8_t mbuf[DBMETASIZE];
	int created_fhp, created_locker, ret, tmp_created, truncating;
	char *real_name, *real_tmpname, *tmpname;

	DB_ASSERT(name != NULL);

	*retidp = TXN_INVALID;

	dbenv = dbp->dbenv;
	LOCK_INIT(elock);
	LOCK_INIT(tmp_lock);
	stxn = NULL;
	created_fhp = created_locker = 0;
	real_name = real_tmpname = tmpname = NULL;
	tmp_created = truncating = 0;

	/*
	 * If we open a file handle and our caller is doing fcntl(2) locking,
	 * we can't close it because that would discard the caller's lock.
	 * Save it until we close the DB handle.
	 */
	if (LF_ISSET(DB_FCNTL_LOCKING)) {
		if ((ret = __os_malloc(dbenv, sizeof(*fhp), &fhp)) != 0)
			return (ret);
		created_fhp = 1;
	} else
		fhp = &fh;
	memset(fhp, 0, sizeof(*fhp));

	/*
	 * Get a lockerid for this handle.  There are paths through queue
	 * rename and remove where this dbp already has a locker, so make
	 * sure we don't clobber it and conflict.
	 */
	if (LOCKING_ON(dbenv) &&
	    !F_ISSET(dbp, DB_AM_COMPENSATE) && dbp->lid == DB_LOCK_INVALIDID) {
		if ((ret = __lock_id(dbenv, &dbp->lid)) != 0)
			goto err;
		created_locker = 1;
	}

	locker = txn == NULL ? dbp->lid : txn->txnid;

	/* Get the real backing file name. */
	if ((ret = __db_appname(dbenv,
	    DB_APP_DATA, name, 0, NULL, &real_name)) != 0)
		goto err;

	/* Fill in the default file mode. */
	if (mode == 0)
		mode = __db_omode("rwrw--");

	oflags = 0;
	if (LF_ISSET(DB_RDONLY))
		oflags |= DB_OSO_RDONLY;

retry:	if (!F_ISSET(dbp, DB_AM_COMPENSATE))
		GET_ENVLOCK(dbenv, locker, &elock);
	if ((ret = __os_exists(real_name, NULL)) == 0) {
		if (LF_ISSET(DB_EXCL)) {
			ret = EEXIST;
			goto err;
		}
reopen:		if ((ret = __fop_read_meta(dbenv, real_name,
		    mbuf, sizeof(mbuf), fhp, 0, oflags)) != 0)
			goto err;

		if ((ret = __db_meta_setup(dbenv,
		    dbp, real_name, (DBMETA *)mbuf, flags, 1)) != 0)
			goto err;

		/* Now, get our handle lock. */
		lmode = LF_ISSET(DB_TRUNCATE) ? DB_LOCK_WRITE : DB_LOCK_READ;
		if ((ret = __fop_lock_handle(dbenv,
		    dbp, locker, lmode, NULL, DB_LOCK_NOWAIT)) == 0) {
			if ((ret = REL_ENVLOCK(dbenv, &elock)) != 0)
				goto err;
		} else {
			/* Someone else has file locked; need to wait. */
			if ((ret = __os_closehandle(dbenv, fhp)) != 0)
				goto err;
			ret = __fop_lock_handle(dbenv,
			    dbp, locker, lmode, &elock, 0);
			if (ret == DB_LOCK_NOTEXIST)
				goto retry;
			if (ret != 0)
				goto err;
			/*
			 * XXX I need to convince myself that I don't need
			 * to re-read the metadata page here.
			 * XXX If you do need to re-read it you'd better
			 * decrypt it too...
			 */
			if ((ret = __os_open(dbenv, real_name, 0, 0, fhp)) != 0)
				goto err;
		}

		/*
		 * Check for a truncate which needs to leap over to the
		 * create case.
		 */
		if (LF_ISSET(DB_TRUNCATE)) {
			/*
			 * Sadly, we need to close and reopen the handle
			 * in order to do the actual truncate.  We couldn't
			 * do the truncate on the initial open because we
			 * needed to read the old file-id in order to lock.
			 */
			if ((ret = __os_closehandle(dbenv, fhp)) != 0)
				goto err;
			if ((ret = __os_open(dbenv,
			    real_name, DB_OSO_TRUNC, 0, fhp)) != 0)
				goto err;
			/*
			 * This is not-transactional, so we'll do the
			 * open/create in-place.
			 */
			tmp_lock = dbp->handle_lock;
			truncating = 1;
			tmpname = (char *)name;
			goto creat2;
		}

		/*
		 * Check for a file in the midst of a rename
		 */
		if (F_ISSET(dbp, DB_AM_IN_RENAME)) {
			if (LF_ISSET(DB_CREATE)) {
				F_CLR(dbp, DB_AM_IN_RENAME);
				goto create;
			} else {
				ret = ENOENT;
				goto err;
			}
		}

		CLOSE_HANDLE(dbp, fhp);
		goto done;
	}

	/* File does not exist. */
	if (!LF_ISSET(DB_CREATE))
		goto err;
	ret = 0;

	/*
	 * Need to create file; we need to set up the file,
	 * the fileid and the locks.  Then we need to call
	 * the appropriate routines to create meta-data pages.
	 */
	if ((ret = REL_ENVLOCK(dbenv, &elock)) != 0)
		goto err;

create:	if ((ret = __db_backup_name(dbenv, name, txn, &tmpname)) != 0)
		goto err;
	if (TXN_ON(dbenv) && txn != NULL &&
	    (ret = dbenv->txn_begin(dbenv, txn, &stxn, 0)) != 0)
		goto err;
	if ((ret = __fop_create(dbenv,
	    stxn, fhp, tmpname, DB_APP_DATA, mode)) != 0)
		goto err;
	tmp_created = 1;
creat2:	if ((ret = __db_appname(dbenv,
	    DB_APP_DATA, tmpname, 0, NULL, &real_tmpname)) != 0)
		goto err;

	/* Set the pagesize if it isn't yet set. */
	if (dbp->pgsize == 0 &&
	    (ret = __fop_set_pgsize(dbp, fhp, real_tmpname)) != 0)
		goto errmsg;

	/* Construct a file_id. */
	if ((ret = __os_fileid(dbenv, real_tmpname, 1, dbp->fileid)) != 0)
		goto errmsg;

	if ((ret = __db_new_file(dbp, stxn, fhp, tmpname)) != 0)
		goto err;
	CLOSE_HANDLE(dbp, fhp);

	/* Now move the file into place. */
	if (!F_ISSET(dbp, DB_AM_COMPENSATE))
		GET_ENVLOCK(dbenv, locker, &elock);
	if (!truncating && __os_exists(real_name, NULL) == 0) {
		/*
		 * Someone managed to create the file; remove our temp
		 * and try to open the file that now exists.
		 */
		(void)__fop_remove(dbenv,
		    NULL, dbp->fileid, tmpname, DB_APP_DATA);
		if (LOCKING_ON(dbenv))
			dbenv->lock_put(dbenv, &dbp->handle_lock);
		LOCK_INIT(dbp->handle_lock);

		/* If we have a saved handle; close it. */
		if (LF_ISSET(DB_FCNTL_LOCKING))
			(void)__os_closehandle(dbenv, fhp);
		if (stxn != NULL) {
			ret = stxn->abort(stxn);
			stxn = NULL;
		}
		if (ret != 0)
			goto err;
		goto reopen;
	}

	/* We've successfully created, move the file into place. */
	if ((ret = __fop_lock_handle(dbenv,
	    dbp, locker, DB_LOCK_WRITE, &elock, 0)) != 0)
		goto err;
	if (!truncating && (ret = __fop_rename(dbenv,
	    stxn, tmpname, name, dbp->fileid, DB_APP_DATA)) != 0)
		goto err;

	/* If this was a truncate; release lock on the old file. */
	if (LOCK_ISSET(tmp_lock) && (ret = __lock_put(dbenv, &tmp_lock)) != 0)
		goto err;

	if (stxn != NULL) {
		*retidp = stxn->txnid;
		ret = stxn->commit(stxn, 0);
		stxn = NULL;
	} else
		*retidp = TXN_INVALID;

	if (ret != 0)
		goto err;

	F_SET(dbp, DB_AM_CREATED);

	if (0) {
errmsg:		__db_err(dbenv, "%s: %s", name, db_strerror(ret));

err:		if (stxn != NULL)
			(void)stxn->abort(stxn);
		if (tmp_created && txn == NULL)
			(void)__fop_remove(dbenv,
			    NULL, NULL, tmpname, DB_APP_DATA);
		if (F_ISSET(fhp, DB_FH_VALID))
			(void)__os_closehandle(dbenv, fhp);
		if (LOCK_ISSET(tmp_lock))
			__lock_put(dbenv, &tmp_lock);
		if (LOCK_ISSET(dbp->handle_lock) && txn == NULL)
			__lock_put(dbenv, &dbp->handle_lock);
		if (LOCK_ISSET(elock))
			(void)REL_ENVLOCK(dbenv, &elock);
		if (created_locker) {
			(void)__lock_id_free(dbenv, dbp->lid);
			dbp->lid = DB_LOCK_INVALIDID;
		}
		if (created_fhp)
			__os_free(dbenv, fhp);
	}

done:	if (!truncating && tmpname != NULL)
		__os_free(dbenv, tmpname);
	if (real_name != NULL)
		__os_free(dbenv, real_name);
	if (real_tmpname != NULL)
		__os_free(dbenv, real_tmpname);

	return (ret);
}

/*
 * __fop_set_pgsize --
 *	Set the page size based on file information.
 */
static int
__fop_set_pgsize(dbp, fhp, name)
	DB *dbp;
	DB_FH *fhp;
	const char *name;
{
	DB_ENV *dbenv;
	u_int32_t iopsize;
	int ret;

	dbenv = dbp->dbenv;

	/*
	 * Use the filesystem's optimum I/O size as the pagesize if a pagesize
	 * not specified.  Some filesystems have 64K as their optimum I/O size,
	 * but as that results in fairly large default caches, we limit the
	 * default pagesize to 16K.
	 */
	if ((ret = __os_ioinfo(dbenv, name, fhp, NULL, NULL, &iopsize)) != 0) {
		__db_err(dbenv, "%s: %s", name, db_strerror(ret));
		return (ret);
	}
	if (iopsize < 512)
		iopsize = 512;
	if (iopsize > 16 * 1024)
		iopsize = 16 * 1024;