FreeBSD/Linux Kernel Cross Reference
sys/sys/shm.h

     /*      $OpenBSD: shm.h,v 1.30 2021/03/10 10:21:47 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 proc;
   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_ */

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