/*      $OpenBSD: shm.h,v 1.31 2024/10/26 05:39:03 jsg Exp $    */
/*      $NetBSD: shm.h,v 1.20 1996/04/09 20:55:35 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_

#ifndef _SYS_IPC_H_
#include <sys/ipc.h>
#endif

#if __BSD_VISIBLE

/* shm-specific sysctl variables corresponding to members of struct shminfo */
#define KERN_SHMINFO_SHMMAX     1       /* int: max shm segment size (bytes) */
#define KERN_SHMINFO_SHMMIN     2       /* int: min shm segment size (bytes) */
#define KERN_SHMINFO_SHMMNI     3       /* int: max number of shm identifiers */
#define KERN_SHMINFO_SHMSEG     4       /* int: max shm segments per process */
#define KERN_SHMINFO_SHMALL     5       /* int: max amount of shm (pages) */
#define KERN_SHMINFO_MAXID      6       /* number of valid shared memory ids */

#define CTL_KERN_SHMINFO_NAMES { \
        { 0, 0 }, \
        { "shmmax", CTLTYPE_INT }, \
        { "shmmin", CTLTYPE_INT }, \
        { "shmmni", CTLTYPE_INT }, \
        { "shmseg", CTLTYPE_INT }, \
        { "shmall", CTLTYPE_INT }, \
}

/*
 * Old (deprecated) access mode definitions--do not use.
 * Provided for compatibility with old code only.
 */
#define SHM_R           IPC_R
#define SHM_W           IPC_W

#endif /* __BSD_VISIBLE */

/*
 * Shared memory operation flags for shmat(2).
 */
#define SHM_RDONLY      010000  /* Attach read-only (else read-write) */
#define SHM_RND         020000  /* Round attach address to SHMLBA */

/*
 * Shared memory specific control commands for shmctl().
 * We accept but ignore these (XXX).
 */
#define SHM_LOCK        3       /* Lock segment in memory. */
#define SHM_UNLOCK      4       /* Unlock a segment locked by SHM_LOCK. */

/*
 * Segment low boundary address multiple
 */
#define SHMLBA          (1U << _MAX_PAGE_SHIFT)

typedef short           shmatt_t;

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 shm op */
        pid_t           shm_cpid;       /* process ID of creator */
        shmatt_t        shm_nattch;     /* number of current attaches */
        time_t          shm_atime;      /* time of last shmat() */
        long            __shm_atimensec;
        time_t          shm_dtime;      /* time of last shmdt() */
        long            __shm_dtimensec;
        time_t          shm_ctime;      /* time of last change by shmctl() */
        long            __shm_ctimensec;
        void            *shm_internal;  /* implementation specific data */
};

#if __BSD_VISIBLE
/*
 * System V 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) */
        int     shmmin;         /* min shared memory segment size (bytes) */
        int     shmmni;         /* max number of shared memory identifiers */
        int     shmseg;         /* max shared memory segments per process */
        int     shmall;         /* max amount of shared memory (pages) */
};

struct shm_sysctl_info {
        struct  shminfo shminfo;
        struct  shmid_ds shmids[1];
};
#endif /* __BSD_VISIBLE */

#ifdef _KERNEL
extern struct shminfo shminfo;
extern struct shmid_ds **shmsegs;

struct vmspace;

void    shminit(void);
void    shmfork(struct vmspace *, struct vmspace *);
void    shmexit(struct vmspace *);
int     sysctl_sysvshm(int *, u_int, void *, size_t *, void *, size_t);

#else /* !_KERNEL */

__BEGIN_DECLS
void *shmat(int, const void *, int);
int shmctl(int, int, struct shmid_ds *);
int shmdt(const void *);
int shmget(key_t, size_t, int);
__END_DECLS

#endif /* !_KERNEL */

#endif /* !_SYS_SHM_H_ */