shm.h

基于组件方式开发操作系统的OSKIT源代码

/*	$NetBSD: shm.h,v 1.15 1994/06/29 06:45:17 cgd Exp $	*/

/*
 * Copyright (c) 1994 Adam Glass
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Adam Glass.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * As defined+described in "X/Open System Interfaces and Headers"
 *                         Issue 4, p. XXX
 */

#ifndef _SYS_SHM_H_
#define _SYS_SHM_H_

#include <sys/ipc.h>

#define SHM_RDONLY  010000  /* Attach read-only (else read-write) */
#define SHM_RND     020000  /* Round attach address to SHMLBA */
#define SHMLBA      CLBYTES /* Segment low boundry address multiple */

/* "official" access mode definitions; somewhat braindead since you have
   to specify (SHM_* >> 3) for group and (SHM_* >> 6) for world permissions */
#define SHM_R       (IPC_R)
#define SHM_W       (IPC_W)


struct shmid_ds {
	struct ipc_perm shm_perm;	/* operation permission structure */
	int             shm_segsz;	/* size of segment in bytes */
	pid_t           shm_lpid;   /* process ID of last shared memory op */
	pid_t           shm_cpid;	/* process ID of creator */
	short		shm_nattch;	/* number of current attaches */
	time_t          shm_atime;	/* time of last shmat() */
	time_t          shm_dtime;	/* time of last shmdt() */
	time_t          shm_ctime;	/* time of last change by shmctl() */
	void           *shm_internal;   /* sysv stupidity */
};

#ifdef KERNEL

/*
 * System 5 style catch-all structure for shared memory constants that
 * might be of interest to user programs.  Do we really want/need this?
 */
struct shminfo {
	int	shmmax,		/* max shared memory segment size (bytes) */
		shmmin,		/* min shared memory segment size (bytes) */
		shmmni,		/* max number of shared memory identifiers */
		shmseg,		/* max shared memory segments per process */
		shmall;		/* max amount of shared memory (pages) */
};
extern struct shminfo	shminfo;
struct shmid_ds	*shmsegs;

void	shminit __P((void));
void	shmexit __P((struct proc *));
void	shmfork __P((struct proc *, struct proc *, int));
#else /* !KERNEL */

#include <sys/cdefs.h>

__BEGIN_DECLS
int shmsys __P((int, ...));
void *shmat  __P((int, void *, int));
int shmget __P((key_t, int, int));
int shmctl __P((int, int, struct shmid_ds *));
int shmdt  __P((void *));
__END_DECLS

#endif /* !KERNEL */

#endif /* !_SYS_SHM_H_ */