userboot/userboot/userboot_disk.c

/*-
 * Copyright (c) 2011 Google, Inc.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * Userboot disk image handling.
 */

#include <sys/disk.h>
#include <stand.h>
#include <stdarg.h>
#include <bootstrap.h>

#include "disk.h"
#include "libuserboot.h"

struct userdisk_info {
    uint64_t    mediasize;
    uint16_t    sectorsize;
};

int userboot_disk_maxunit = 0;

static int userdisk_maxunit = 0;
static struct userdisk_info *ud_info;

static int  userdisk_init(void);
static void userdisk_cleanup(void);
static int  userdisk_strategy(void *devdata, int flag, daddr_t dblk,
            size_t size, char *buf, size_t *rsize);
static int  userdisk_open(struct open_file *f, ...);
static int  userdisk_close(struct open_file *f);
static int  userdisk_ioctl(struct open_file *f, u_long cmd, void *data);
static void userdisk_print(int verbose);

struct devsw userboot_disk = {
    "disk",
    DEVT_DISK,
    userdisk_init,
    userdisk_strategy,
    userdisk_open,
    userdisk_close,
    userdisk_ioctl,
    userdisk_print,
    userdisk_cleanup
};

/*
 * Initialize userdisk_info structure for each disk.
 */
static int
userdisk_init(void)
{
    off_t mediasize;
    u_int sectorsize;
    int i;

    userdisk_maxunit = userboot_disk_maxunit;
    if (userdisk_maxunit > 0) {
        ud_info = malloc(sizeof(*ud_info) * userdisk_maxunit);
        if (ud_info == NULL)
            return (ENOMEM);
        for (i = 0; i < userdisk_maxunit; i++) {
            if (CALLBACK(diskioctl, i, DIOCGSECTORSIZE,
                &sectorsize) != 0 || CALLBACK(diskioctl, i,
                DIOCGMEDIASIZE, &mediasize) != 0)
                return (ENXIO);
            ud_info[i].mediasize = mediasize;
            ud_info[i].sectorsize = sectorsize;
        }
    }

    return(0);
}

static void
userdisk_cleanup(void)
{

    if (userdisk_maxunit > 0)
        free(ud_info);
    disk_cleanup(&userboot_disk);
}

/*
 * Print information about disks
 */
static void
userdisk_print(int verbose)
{
    struct disk_devdesc dev;
    char line[80];
    int i;

    for (i = 0; i < userdisk_maxunit; i++) {
        sprintf(line, "    disk%d:   Guest drive image\n", i);
        pager_output(line);
        dev.d_dev = &userboot_disk;
        dev.d_unit = i;
        dev.d_slice = -1;
        dev.d_partition = -1;
        if (disk_open(&dev, ud_info[i].mediasize,
            ud_info[i].sectorsize, 0) == 0) {
            sprintf(line, "    disk%d", i);
            disk_print(&dev, line, verbose);
            disk_close(&dev);
        }
    }
}

/*
 * Attempt to open the disk described by (dev) for use by (f).
 */
static int
userdisk_open(struct open_file *f, ...)
{
    va_list         ap;
    struct disk_devdesc *dev;

    va_start(ap, f);
    dev = va_arg(ap, struct disk_devdesc *);
    va_end(ap);

    if (dev->d_unit < 0 || dev->d_unit >= userdisk_maxunit)
        return (EIO);

    return (disk_open(dev, ud_info[dev->d_unit].mediasize,
        ud_info[dev->d_unit].sectorsize, 0));
}

static int
userdisk_close(struct open_file *f)
{
    struct disk_devdesc *dev;

    dev = (struct disk_devdesc *)f->f_devdata;
    return (disk_close(dev));
}

static int
userdisk_strategy(void *devdata, int rw, daddr_t dblk, size_t size,
    char *buf, size_t *rsize)
{
    struct disk_devdesc *dev = devdata;
    uint64_t    off;
    size_t      resid;
    int     rc;

    if (rw == F_WRITE)
        return (EROFS);
    if (rw != F_READ)
        return (EINVAL);
    if (rsize)
        *rsize = 0;
    off = (dblk + dev->d_offset) * ud_info[dev->d_unit].sectorsize;
    rc = CALLBACK(diskread, dev->d_unit, off, buf, size, &resid);
    if (rc)
        return (rc);
    if (rsize)
        *rsize = size - resid;
    return (0);
}

static int
userdisk_ioctl(struct open_file *f, u_long cmd, void *data)
{
    struct disk_devdesc *dev;

    dev = (struct disk_devdesc *)f->f_devdata;
    return (CALLBACK(diskioctl, dev->d_unit, cmd, data));
}