1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 23 /* All Rights Reserved */ 24 25 26 #ifndef _SYS_OPEN_H 27 #define _SYS_OPEN_H 28 29 #ifdef __cplusplus 30 extern "C" { 31 #endif 32 33 /* 34 * Some drivers need to be able to keep accurate records of open/close 35 * calls to determine whether a device is still in use. To allow this 36 * open/close calls have been typed and the type is passed as a third 37 * argument in open/close calls, as in: 38 * (*cdevsw[getmajor(dev)].d_open)(getminor(dev), flag, OTYP_CHR); 39 * or 40 * (*cdevsw[getmajor(dev)].d_close)(getminor(dev), flag, OTYP_CHR); 41 * Five types of open/close calls have been defined: 42 * OTYP_BLK: open/close of a block special file 43 * OTYP_MNT: open/close for mounting/unmounting a file system 44 * OTYP_CHR: open/close of a character special file 45 * OTYP_SWP: open/close of a swapping device. 46 * OTYP_LYR: open/close calls from a driver to another driver, 47 * without a file being open for the dev of the lower driver. 48 * 49 * The first four types of open/close calls obey the protocol rule 50 * that many more opens may occur for a given minor(dev) for that type of open, 51 * but a close call happens only on the last close of that dev. 52 * This protocol allows a flag to be used (set by opens, cleared by closes) 53 * to keep track of the state for a given minor device value. 54 * 55 * Calls of the fifth type (OTYP_LYR) must obey the protocol rule 56 * that open and close call calls are always paired. This protocol 57 * permits several drivers to be layers above the same device driver. 58 * A counter can be used for this protocol. 59 * 60 * The value OTYPCNT is defined for the purpose of declaring arrays 61 * in drivers and for performing range checks (0 <= otyp < OTYPCNT) 62 * on values passed. 63 */ 64 65 #define OTYPCNT 5 66 #define OTYP_BLK 0 67 #define OTYP_MNT 1 68 #define OTYP_CHR 2 69 #define OTYP_SWP 3 70 #define OTYP_LYR 4 71 72 #ifdef __cplusplus 73 } 74 #endif 75 76 #endif /* _SYS_OPEN_H */ 77