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Diffstat (limited to 'usr/src/uts/common/sys/open.h')
| -rw-r--r-- | usr/src/uts/common/sys/open.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/usr/src/uts/common/sys/open.h b/usr/src/uts/common/sys/open.h new file mode 100644 index 0000000000..b7c95ddb2e --- /dev/null +++ b/usr/src/uts/common/sys/open.h @@ -0,0 +1,78 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License, Version 1.0 only + * (the "License"). You may not use this file except in compliance + * with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ +/* All Rights Reserved */ + + +#ifndef _SYS_OPEN_H +#define _SYS_OPEN_H + +#pragma ident "%Z%%M% %I% %E% SMI" /* from SVR4 11.4 */ + +#ifdef __cplusplus +extern "C" { +#endif + +/* + * Some drivers need to be able to keep accurate records of open/close + * calls to determine whether a device is still in use. To allow this + * open/close calls have been typed and the type is passed as a third + * argument in open/close calls, as in: + * (*cdevsw[getmajor(dev)].d_open)(getminor(dev), flag, OTYP_CHR); + * or + * (*cdevsw[getmajor(dev)].d_close)(getminor(dev), flag, OTYP_CHR); + * Five types of open/close calls have been defined: + * OTYP_BLK: open/close of a block special file + * OTYP_MNT: open/close for mounting/unmounting a file system + * OTYP_CHR: open/close of a character special file + * OTYP_SWP: open/close of a swapping device. + * OTYP_LYR: open/close calls from a driver to another driver, + * without a file being open for the dev of the lower driver. + * + * The first four types of open/close calls obey the protocol rule + * that many more opens may occur for a given minor(dev) for that type of open, + * but a close call happens only on the last close of that dev. + * This protocol allows a flag to be used (set by opens, cleared by closes) + * to keep track of the state for a given minor device value. + * + * Calls of the fifth type (OTYP_LYR) must obey the protocol rule + * that open and close call calls are always paired. This protocol + * permits several drivers to be layers above the same device driver. + * A counter can be used for this protocol. + * + * The value OTYPCNT is defined for the purpose of declaring arrays + * in drivers and for performing range checks (0 <= otyp < OTYPCNT) + * on values passed. + */ + +#define OTYPCNT 5 +#define OTYP_BLK 0 +#define OTYP_MNT 1 +#define OTYP_CHR 2 +#define OTYP_SWP 3 +#define OTYP_LYR 4 + +#ifdef __cplusplus +} +#endif + +#endif /* _SYS_OPEN_H */ |