/*      $OpenBSD: file.h,v 1.66 2022/06/20 01:39:44 visa Exp $  */
/*      $NetBSD: file.h,v 1.11 1995/03/26 20:24:13 jtc Exp $    */

/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *      @(#)file.h      8.2 (Berkeley) 8/20/94
 */

#ifndef _KERNEL
#include <sys/fcntl.h>

#else /* _KERNEL */
#include <sys/queue.h>
#include <sys/mutex.h>
#endif /* _KERNEL */

#define DTYPE_VNODE     1       /* file */
#define DTYPE_SOCKET    2       /* communications endpoint */
#define DTYPE_PIPE      3       /* pipe */
#define DTYPE_KQUEUE    4       /* event queue */
#define DTYPE_DMABUF    5       /* DMA buffer (for DRM) */
#define DTYPE_SYNC      6       /* sync file (for DRM) */

#ifdef _KERNEL
struct proc;
struct uio;
struct knote;
struct stat;
struct file;
struct ucred;

/**
 * File operations.
 * The following entries could be called without KERNEL_LOCK hold:
 * - fo_read
 * - fo_write
 * - fo_close
 */
struct  fileops {
        int     (*fo_read)(struct file *, struct uio *, int);
        int     (*fo_write)(struct file *, struct uio *, int);
        int     (*fo_ioctl)(struct file *, u_long, caddr_t, struct proc *);
        int     (*fo_kqfilter)(struct file *, struct knote *);
        int     (*fo_stat)(struct file *, struct stat *, struct proc *);
        int     (*fo_close)(struct file *, struct proc *);
        int     (*fo_seek)(struct file *, off_t *, int, struct proc *);
};
#define FO_POSITION     0x00000001      /* positioned read/write */

/*
 * Kernel descriptor table.
 * One entry for each open kernel vnode and socket.
 *
 *  Locks used to protect struct members in this file:
 *      I       immutable after creation
 *      F       global `fhdlk' mutex
 *      a       atomic operations
 *      f       per file `f_mtx'
 *      v       vnode lock
 */
struct file {
        LIST_ENTRY(file) f_list;/* [F] list of active files */
        struct mutex f_mtx;
        u_int   f_flag;         /* [a] see fcntl.h */
        u_int   f_iflags;       /* [a] internal flags */
        int     f_type;         /* [I] descriptor type */
        u_int   f_count;        /* [a] reference count */
        struct  ucred *f_cred;  /* [I] credentials associated with descriptor */
        const struct fileops *f_ops; /* [I] file operation pointers */
        off_t   f_offset;       /* [f,v] offset */
        void    *f_data;        /* [I] private data */
        uint64_t f_rxfer;       /* [f] total number of read transfers */
        uint64_t f_wxfer;       /* [f] total number of write transfers */
        uint64_t f_seek;        /* [f] total independent seek operations */
        uint64_t f_rbytes;      /* [f] total bytes read */
        uint64_t f_wbytes;      /* [f] total bytes written */
};

#define FIF_HASLOCK             0x01    /* descriptor holds advisory lock */
#define FIF_INSERTED            0x80    /* present in `filehead' */

#define FREF(fp) \
        do { \
                extern void vfs_stall_barrier(void); \
                vfs_stall_barrier(); \
                atomic_inc_int(&(fp)->f_count); \
        } while (0)

#define FRELE(fp,p) \
        (atomic_dec_int_nv(&fp->f_count) == 0 ? fdrop(fp, p) : 0)

#define FDUP_MAX_COUNT          (UINT_MAX - 2 * MAXCPUS)

int     fdrop(struct file *, struct proc *);

static inline off_t
foffset(struct file *fp)
{
        off_t offset;

        mtx_enter(&fp->f_mtx);
        offset = fp->f_offset;
        mtx_leave(&fp->f_mtx);
        return (offset);
}

LIST_HEAD(filelist, file);
extern int maxfiles;                    /* kernel limit on number of open files */
extern int numfiles;                    /* actual number of open files */
extern const struct fileops socketops;  /* socket operations for files */
extern const struct fileops vnops;      /* vnode operations for files */

#endif /* _KERNEL */