/*
 * Copyright (c) 1996 John S. Dyson
 * All rights reserved.
 * Copyright (c) 2003-2017 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * 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 immediately at the beginning of the file, without modification,
 *    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. Absolutely no warranty of function or purpose is made by the author
 *    John S. Dyson.
 * 4. This work was done expressly for inclusion into FreeBSD.  Other use
 *    is allowed if this notation is included.
 * 5. Modifications may be freely made to this file if the above conditions
 *    are met.
 */

#ifndef _SYS_PIPE_H_
#define _SYS_PIPE_H_

#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)

#ifndef _SYS_TYPES_H_
#include <sys/types.h>
#endif
#ifndef _SYS_TIME_H_
#include <sys/time.h>                   /* for struct timespec */
#endif
#ifndef _SYS_EVENT_H_
#include <sys/event.h>                  /* for struct kqinfo */
#endif
#ifndef _SYS_XIO_H_
#include <sys/xio.h>                    /* for struct xio */
#endif
#ifndef _SYS_THREAD_H_
#include <sys/thread.h>                 /* for struct lwkt_token */
#endif
#ifndef _MACHINE_PARAM_H_
#include <machine/param.h>              /* for PAGE_SIZE */
#endif

/*
 * Pipe buffer information.
 */
struct pipebuf {
        struct {
                struct lwkt_token rlock;
                size_t          rindex; /* current read index (FIFO)    */
                int32_t         rip;    /* blocking read requested (FIFO) */
                int32_t         unu01;  /* blocking read requested (FIFO) */
                struct timespec atime;  /* time of last access */
        } __cachealign;
        struct {
                struct lwkt_token wlock;
                size_t          windex; /* current write index (FIFO)   */
                int32_t         wip;
                int32_t         unu02;
                struct timespec mtime;  /* time of last modify */
        } __cachealign;
        size_t          size;           /* size of buffer */
        caddr_t         buffer;         /* kva of buffer */
        struct vm_object *object;       /* VM object containing buffer */
        struct kqinfo   kq;             /* for compat with select/poll/kq */
        struct sigio    *sigio;         /* information for async I/O */
        uint32_t        state;          /* pipe status info */
        int             lticks;         /* vfs_timestamp optimization */
} __cachealign;

/*
 * Bits in pipebuf.state.
 */
#define PIPE_ASYNC      0x0004  /* Async? I/O */
#define PIPE_WANTR      0x0008  /* Reader wants some characters */
#define PIPE_WANTW      0x0010  /* Writer wants space to put characters */
#define PIPE_REOF       0x0040  /* Pipe is in EOF condition (read EOF) */
#define PIPE_WEOF       0x0080  /* Pipe is in EOF condition (write shutdown) */
#define PIPE_CLOSED     0x1000  /* Pipe has been closed */

/*
 * The pipe() data structure encompasses two pipes.  Bit 0 in fp->f_data
 * denotes which.
 */
struct pipe {
        struct pipebuf  bufferA;        /* data storage */
        struct pipebuf  bufferB;        /* data storage */
        struct timespec ctime;          /* time of status change */
        struct pipe     *next;
        uint32_t        open_count;
        uint32_t        unused01;
        uint64_t        inum;
} __cachealign;

#endif  /* _KERNEL || _KERNEL_STRUCTURES */
#endif /* !_SYS_PIPE_H_ */