/*-
 * 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.
 */

/*
 * 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             ud_open;        /* reference counter */
        void            *ud_bcache;     /* buffer cache data */
};

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_realstrategy(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 int      userdisk_print(int verbose);

struct devsw userboot_disk = {
        .dv_name = "disk",
        .dv_type = DEVT_DISK,
        .dv_init = userdisk_init,
        .dv_strategy = userdisk_strategy,
        .dv_open = userdisk_open,
        .dv_close = userdisk_close,
        .dv_ioctl = userdisk_ioctl,
        .dv_print = userdisk_print,
        .dv_cleanup = userdisk_cleanup,
        .dv_fmtdev = disk_fmtdev,
        .dv_parsedev = disk_parsedev,
};

/*
 * 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;
                        ud_info[i].ud_open = 0;
                        ud_info[i].ud_bcache = NULL;
                }
        }
        bcache_add_dev(userdisk_maxunit);
        return(0);
}

static void
userdisk_cleanup(void)
{

        if (userdisk_maxunit > 0)
                free(ud_info);
}

/*
 * Print information about disks
 */
static int
userdisk_print(int verbose)
{
        struct disk_devdesc dev;
        char line[80];
        int i, ret = 0;

        if (userdisk_maxunit == 0)
                return (0);

        printf("%s devices:", userboot_disk.dv_name);
        if ((ret = pager_output("\n")) != 0)
                return (ret);

        for (i = 0; i < userdisk_maxunit; i++) {
                snprintf(line, sizeof(line),
                    "    disk%d:   Guest drive image\n", i);
                ret = pager_output(line);
                if (ret != 0)
                        break;
                dev.dd.d_dev = &userboot_disk;
                dev.dd.d_unit = i;
                dev.d_slice = D_SLICENONE;
                dev.d_partition = D_PARTNONE;
                if (disk_open(&dev, ud_info[i].mediasize,
                    ud_info[i].sectorsize) == 0) {
                        snprintf(line, sizeof(line), "    disk%d", i);
                        ret = disk_print(&dev, line, verbose);
                        disk_close(&dev);
                        if (ret != 0)
                                break;
                }
        }
        return (ret);
}

/*
 * 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->dd.d_unit < 0 || dev->dd.d_unit >= userdisk_maxunit)
                return (EIO);
        ud_info[dev->dd.d_unit].ud_open++;
        if (ud_info[dev->dd.d_unit].ud_bcache == NULL)
                ud_info[dev->dd.d_unit].ud_bcache = bcache_allocate();
        return (disk_open(dev, ud_info[dev->dd.d_unit].mediasize,
            ud_info[dev->dd.d_unit].sectorsize));
}

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

        dev = (struct disk_devdesc *)f->f_devdata;
        ud_info[dev->dd.d_unit].ud_open--;
        if (ud_info[dev->dd.d_unit].ud_open == 0) {
                bcache_free(ud_info[dev->dd.d_unit].ud_bcache);
                ud_info[dev->dd.d_unit].ud_bcache = NULL;
        }
        return (disk_close(dev));
}

static int
userdisk_strategy(void *devdata, int rw, daddr_t dblk, size_t size,
    char *buf, size_t *rsize)
{
        struct bcache_devdata bcd;
        struct disk_devdesc *dev;

        dev = (struct disk_devdesc *)devdata;
        bcd.dv_strategy = userdisk_realstrategy;
        bcd.dv_devdata = devdata;
        bcd.dv_cache = ud_info[dev->dd.d_unit].ud_bcache;
        return (bcache_strategy(&bcd, rw, dblk + dev->d_offset,
            size, buf, rsize));
}

static int
userdisk_realstrategy(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 (rsize)
                *rsize = 0;
        off = dblk * ud_info[dev->dd.d_unit].sectorsize;
        switch (rw & F_MASK) {
        case F_READ:
                rc = CALLBACK(diskread, dev->dd.d_unit, off, buf, size, &resid);
                break;
        case F_WRITE:
                rc = CALLBACK(diskwrite, dev->dd.d_unit, off, buf, size,
                    &resid);
                break;
        default:
                rc = EINVAL;
                break;
        }
        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;
        int rc;

        dev = (struct disk_devdesc *)f->f_devdata;
        rc = disk_ioctl(dev, cmd, data);
        if (rc != ENOTTY)
                return (rc);

        return (CALLBACK(diskioctl, dev->dd.d_unit, cmd, data));
}