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/* $OpenBSD: file.h,v 1.61 2020/03/13 10:07:01 anton 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>
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_poll)(struct file *, int, 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 */
#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) */
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 */
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