/*      $NetBSD: buf.c,v 1.28 2023/03/14 10:36:06 kre Exp $     */

/*
* Copyright (c) 2001 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Luke Mewburn for Wasabi Systems, Inc.
*
* 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 for the NetBSD Project by
*      Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
*    or promote products derived from this software without specific prior
*    written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if defined(__RCSID) && !defined(__lint)
__RCSID("$NetBSD: buf.c,v 1.28 2023/03/14 10:36:06 kre Exp $");
#endif  /* !__lint */

#include <sys/param.h>
#include <sys/time.h>

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <util.h>

#include "makefs.h"
#include "buf.h"

TAILQ_HEAD(buftailhead,buf) buftail;

int
bread(struct vnode *vp, daddr_t blkno, int size, int u2 __unused,
       struct buf **bpp)
{
       off_t   offset;
       ssize_t rv;
       fsinfo_t *fs = vp->fs;
       int saved_errno;

       assert (bpp != NULL);

       if (debug & DEBUG_BUF_BREAD)
               printf("%s: blkno %jd size %d\n", __func__,
                   (intmax_t)blkno, size);
       *bpp = getblk(vp, blkno, size, 0, 0);
       offset = (*bpp)->b_blkno * fs->sectorsize + fs->offset;
       if (debug & DEBUG_BUF_BREAD)
               printf("%s: blkno %jd offset %jd bcount %ld\n", __func__,
                   (intmax_t)(*bpp)->b_blkno, (intmax_t) offset,
                   (*bpp)->b_bcount);
       if (lseek((*bpp)->b_fs->fd, offset, SEEK_SET) == -1) {
               saved_errno = errno;
               warn("%s: lseek %jd (%jd)", __func__,
                   (intmax_t)(*bpp)->b_blkno, (intmax_t)offset);
               goto out;
       }
       rv = read((*bpp)->b_fs->fd, (*bpp)->b_data, (size_t)(*bpp)->b_bcount);
       saved_errno = errno;
       if (debug & DEBUG_BUF_BREAD)
               printf("%s: read %ld (%jd) returned %zd\n", __func__,
                   (*bpp)->b_bcount, (intmax_t)offset, rv);
       if (rv == -1) {                         /* read error */
               warn("%s: read %ld (%jd) returned %zd", __func__,
                   (*bpp)->b_bcount, (intmax_t)offset, rv);
               goto out;
       }
       if (rv != (*bpp)->b_bcount) {   /* short read */
               saved_errno = ENOSPC;
               warn("%s: read %ld (%jd) returned %zd", __func__,
                   (*bpp)->b_bcount, (intmax_t)offset, rv);
               goto out;
       }
       return 0;
out:
       brelse(*bpp, 0);
       *bpp = NULL;
#if 1
       __USE(saved_errno);
       exit(EXIT_FAILURE);
#else
       return saved_errno;
#endif
}

void
brelse(struct buf *bp, int u1 __unused)
{

       assert (bp != NULL);
       assert (bp->b_data != NULL);

       if (bp->b_lblkno < 0) {
               /*
                * XXX  don't remove any buffers with negative logical block
                *      numbers (lblkno), so that we retain the mapping
                *      of negative lblkno -> real blkno that ffs_balloc()
                *      sets up.
                *
                *      if we instead released these buffers, and implemented
                *      ufs_strategy() (and ufs_bmaparray()) and called those
                *      from bread() and bwrite() to convert the lblkno to
                *      a real blkno, we'd add a lot more code & complexity
                *      and reading off disk, for little gain, because this
                *      simple hack works for our purpose.
                */
               bp->b_bcount = 0;
               return;
       }

       TAILQ_REMOVE(&buftail, bp, b_tailq);
       free(bp->b_data);
       free(bp);
}

int
bwrite(struct buf *bp)
{
       off_t   offset;
       ssize_t rv;
       size_t  bytes;
       int     e;
       fsinfo_t *fs = bp->b_fs;

       assert (bp != NULL);
       offset = bp->b_blkno * fs->sectorsize + fs->offset;
       bytes  = (size_t)bp->b_bcount;
       if (debug & DEBUG_BUF_BWRITE)
               printf("%s: blkno %jd offset %jd bcount %zu\n", __func__,
                   (intmax_t)bp->b_blkno, (intmax_t) offset, bytes);
       if (lseek(bp->b_fs->fd, offset, SEEK_SET) == -1)
               return errno;
       rv = write(bp->b_fs->fd, bp->b_data, bytes);
       e = errno;
       if (debug & DEBUG_BUF_BWRITE)
               printf("%s: write %ld (offset %jd) returned %jd\n", __func__,
                   bp->b_bcount, (intmax_t)offset, (intmax_t)rv);
       brelse(bp, 0);
       if (rv == (ssize_t)bytes)
               return 0;
       if (rv == -1)           /* write error */
               return e;
       return EAGAIN;
}

void
bcleanup(void)
{
       struct buf *bp;

       /*
        * XXX  this really shouldn't be necessary, but i'm curious to
        *      know why there's still some buffers lying around that
        *      aren't brelse()d
        */

       if (TAILQ_EMPTY(&buftail))
               return;

       printf("%s: unflushed buffers:\n", __func__);
       TAILQ_FOREACH(bp, &buftail, b_tailq) {
               printf("\tlblkno %10jd blkno %10jd count %6ld  bufsize %6ld\n",
                   (intmax_t)bp->b_lblkno, (intmax_t)bp->b_blkno,
                   bp->b_bcount, bp->b_bufsize);
       }
       printf("%s: done\n", __func__);
}

struct buf *
getblk(struct vnode *vp, daddr_t blkno, int size, int u1 __unused,
   int u2 __unused)
{
       static int buftailinitted;
       struct buf *bp;
       void *n;

       if (debug & DEBUG_BUF_GETBLK)
               printf("%s: blkno %jd size %d\n", __func__,
                   (intmax_t)blkno, size);

       bp = NULL;
       if (!buftailinitted) {
               if (debug & DEBUG_BUF_GETBLK)
                       printf("%s: initialising tailq\n", __func__);
               TAILQ_INIT(&buftail);
               buftailinitted = 1;
       } else {
               TAILQ_FOREACH(bp, &buftail, b_tailq) {
                       if (bp->b_lblkno != blkno)
                               continue;
                       break;
               }
       }
       if (bp == NULL) {
               bp = ecalloc(1, sizeof(*bp));
               bp->b_bufsize = 0;
               bp->b_blkno = bp->b_lblkno = blkno;
               bp->b_fs = vp->fs;
               bp->b_data = NULL;
               TAILQ_INSERT_HEAD(&buftail, bp, b_tailq);
       }
       bp->b_bcount = size;
       if (bp->b_data == NULL || bp->b_bcount > bp->b_bufsize) {
               n = erealloc(bp->b_data, (size_t)size);
               memset(n, 0, (size_t)size);
               bp->b_data = n;
               bp->b_bufsize = size;
       }

       return bp;
}

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