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block.c

/*
 * Copyright (c) 2002 Juli Mallett.  All rights reserved.
 *
 * This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
 * FreeBSD project.  Redistribution and use in source and binary forms, with
 * or without modification, are permitted provided that the following
 * conditions are met:
 *
 * 1. Redistribution of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistribution 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.
 *
 * 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libufs/block.c,v 1.10 2003/10/07 07:12:22 phk Exp $");

#include <sys/param.h>
#include <sys/mount.h>
#include <sys/disklabel.h>
#include <sys/stat.h>

#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <libufs.h>

ssize_t
bread(struct uufsd *disk, ufs2_daddr_t blockno, void *data, size_t size)
{
      void *p2;
      ssize_t cnt;

      ERROR(disk, NULL);

      p2 = data;
      /*
       * XXX: various disk controllers require alignment of our buffer
       * XXX: which is stricter than struct alignment.
       * XXX: Bounce the buffer if not 64 byte aligned.
       * XXX: this can be removed if/when the kernel is fixed
       */
      if (((intptr_t)data) & 0x3f) {
            p2 = malloc(size);
            if (p2 == NULL)
                  ERROR(disk, "allocate bounce buffer");
      }
      cnt = pread(disk->d_fd, p2, size, (off_t)(blockno * disk->d_bsize));
      if (cnt == -1) {
            ERROR(disk, "read error from block device");
            goto fail;
      }
      if (cnt == 0) {
            ERROR(disk, "end of file from block device");
            goto fail;
      }
      if ((size_t)cnt != size) {
            ERROR(disk, "short read or read error from block device");
            goto fail;
      }
      if (p2 != data) {
            memcpy(data, p2, size);
            free(p2);
      }
      return (cnt);
fail: memset(data, 0, size);
      if (p2 != data) {
            free(p2);
      }
      return (-1);
}

ssize_t
bwrite(struct uufsd *disk, ufs2_daddr_t blockno, const void *data, size_t size)
{
      ssize_t cnt;
      int rv;
      void *p2 = NULL;

      ERROR(disk, NULL);

      rv = ufs_disk_write(disk);
      if (rv == -1) {
            ERROR(disk, "failed to open disk for writing");
            return (-1);
      }

      /*
       * XXX: various disk controllers require alignment of our buffer
       * XXX: which is stricter than struct alignment.
       * XXX: Bounce the buffer if not 64 byte aligned.
       * XXX: this can be removed if/when the kernel is fixed
       */
      if (((intptr_t)data) & 0x3f) {
            p2 = malloc(size);
            if (p2 == NULL)
                  ERROR(disk, "allocate bounce buffer");
            memcpy(p2, data, size);
            data = p2;
      }
      cnt = pwrite(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
      if (p2 != NULL)
            free(p2);
      if (cnt == -1) {
            ERROR(disk, "write error to block device");
            return (-1);
      }
      if ((size_t)cnt != size) {
            ERROR(disk, "short write to block device");
            return (-1);
      }

      return (cnt);
}

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