freebsd-dev/lib/libufs/sblock.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * 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("$FreeBSD$");

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

#include <libufs.h>

int
sbread(struct uufsd *disk)
{
	struct fs *fs;

	ERROR(disk, NULL);

	if ((errno = sbget(disk->d_fd, &fs, -1)) != 0) {
		switch (errno) {
		case EIO:
			ERROR(disk, "non-existent or truncated superblock");
			break;
		case ENOENT:
			ERROR(disk, "no usable known superblock found");
			break;
		case ENOSPC:
			ERROR(disk, "failed to allocate space for superblock "
			    "information");
			break;
		case EINVAL:
			ERROR(disk, "The previous newfs operation on this "
			    "volume did not complete.\nYou must complete "
			    "newfs before using this volume.");
			break;
		default:
			ERROR(disk, "unknown superblock read error");
			errno = EIO;
			break;
		}
		disk->d_ufs = 0;
		return (-1);
	}
	memcpy(&disk->d_fs, fs, fs->fs_sbsize);
	free(fs);
	fs = &disk->d_fs;
	if (fs->fs_magic == FS_UFS1_MAGIC)
		disk->d_ufs = 1;
	if (fs->fs_magic == FS_UFS2_MAGIC)
		disk->d_ufs = 2;
	disk->d_bsize = fs->fs_fsize / fsbtodb(fs, 1);
	disk->d_sblock = fs->fs_sblockloc / disk->d_bsize;
	disk->d_sbcsum = fs->fs_csp;
	return (0);
}

int
sbwrite(struct uufsd *disk, int all)
{
	struct fs *fs;
	int rv;

	ERROR(disk, NULL);

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

	fs = &disk->d_fs;
	if ((errno = sbput(disk->d_fd, fs, all ? fs->fs_ncg : 0)) != 0) {
		switch (errno) {
		case EIO:
			ERROR(disk, "failed to write superblock");
			break;
		default:
			ERROR(disk, "unknown superblock write error");
			errno = EIO;
			break;
		}
		return (-1);
	}
	return (0);
}

/*
 * These are the low-level functions that actually read and write
 * the superblock and its associated data. The actual work is done by
 * the functions ffs_sbget and ffs_sbput in /sys/ufs/ffs/ffs_subr.c.
 */
static int use_pread(void *devfd, off_t loc, void **bufp, int size);
static int use_pwrite(void *devfd, off_t loc, void *buf, int size);

/*
 * Read a superblock from the devfd device allocating memory returned
 * in fsp. Also read the superblock summary information.
 */
int
sbget(int devfd, struct fs **fsp, off_t sblockloc)
{

	return (ffs_sbget(&devfd, fsp, sblockloc, "user", use_pread));
}

/*
 * A read function for use by user-level programs using libufs.
 */
static int
use_pread(void *devfd, off_t loc, void **bufp, int size)
{
	int fd;

	fd = *(int *)devfd;
	if ((*bufp = malloc(size)) == NULL)
		return (ENOSPC);
	if (pread(fd, *bufp, size, loc) != size)
		return (EIO);
	return (0);
}

/*
 * Write a superblock to the devfd device from the memory pointed to by fs.
 * Also write out the superblock summary information but do not free the
 * summary information memory.
 *
 * Additionally write out numaltwrite of the alternate superblocks. Use
 * fs->fs_ncg to write out all of the alternate superblocks.
 */
int
sbput(int devfd, struct fs *fs, int numaltwrite)
{
	struct csum *savedcsp;
	off_t savedactualloc;
	int i, error;

	if ((error = ffs_sbput(&devfd, fs, fs->fs_sblockactualloc,
	     use_pwrite)) != 0)
		return (error);
	if (numaltwrite == 0)
		return (0);
	savedactualloc = fs->fs_sblockactualloc;
	savedcsp = fs->fs_csp;
	fs->fs_csp = NULL;
	for (i = 0; i < numaltwrite; i++) {
		fs->fs_sblockactualloc = dbtob(fsbtodb(fs, cgsblock(fs, i)));
		if ((error = ffs_sbput(&devfd, fs, fs->fs_sblockactualloc,
		     use_pwrite)) != 0) {
			fs->fs_sblockactualloc = savedactualloc;
			fs->fs_csp = savedcsp;
			return (-1);
		}
	}
	fs->fs_sblockactualloc = savedactualloc;
	fs->fs_csp = savedcsp;
	return (0);
}

/*
 * A write function for use by user-level programs using sbput in libufs.
 */
static int
use_pwrite(void *devfd, off_t loc, void *buf, int size)
{
	int fd;

	fd = *(int *)devfd;
	if (pwrite(fd, buf, size, loc) != size)
		return (EIO);
	return (0);
}