/*      $NetBSD: dkwedge_mbr.c,v 1.13 2024/02/26 21:55:05 charlotte Exp $       */

/*-
* Copyright (c) 2004 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

/*
* Master Boot Record partition table support for disk wedges
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dkwedge_mbr.c,v 1.13 2024/02/26 21:55:05 charlotte Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/disk.h>
#include <sys/vnode.h>
#include <sys/buf.h>

#include <sys/bootblock.h>
#include <sys/disklabel.h>

typedef struct mbr_args {
       struct disk     *pdk;
       struct vnode    *vp;
       struct buf      *bp;
       int             error;
       uint32_t        secsize;
       int             mbr_count;
} mbr_args_t;

static const char *
mbr_ptype_to_str(uint8_t ptype)
{
       const char *str;

       switch (ptype) {
       case MBR_PTYPE_FAT12:   str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_FAT16S:  str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_FAT16B:  str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_NTFS:    str = DKW_PTYPE_NTFS;           break;
       case MBR_PTYPE_FAT32:   str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_FAT32L:  str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_FAT16L:  str = DKW_PTYPE_FAT;            break;
       case MBR_PTYPE_LNXSWAP: str = DKW_PTYPE_SWAP;           break;
       case MBR_PTYPE_LNXEXT2: str = DKW_PTYPE_EXT2FS;         break;
       case MBR_PTYPE_APPLE_UFS:str = DKW_PTYPE_APPLEUFS;      break;
       case MBR_PTYPE_EFI:     str = DKW_PTYPE_FAT;            break;
       default:                str = NULL;                     break;
       }

       return (str);
}

static void
getparts(mbr_args_t *a, uint32_t off, uint32_t extoff)
{
       struct dkwedge_info dkw;
       struct mbr_partition *dp;
       struct mbr_sector *mbr;
       const char *ptype;
       int i, error;

       error = dkwedge_read(a->pdk, a->vp, off, a->bp->b_data, a->secsize);
       if (error) {
               a->error = error;
               aprint_error("%s: unable to read MBR @ %u/%u, "
                   "error = %d\n", a->pdk->dk_name, off, a->secsize, a->error);
               return;
       }

       mbr = a->bp->b_data;
       if (mbr->mbr_magic != htole16(MBR_MAGIC))
               return;

       dp = mbr->mbr_parts;

       for (i = 0; i < MBR_PART_COUNT; i++) {
               switch (dp[i].mbrp_type) {
               case 0:                 /* empty */
               case MBR_PTYPE_PMBR:    /* Handled by GPT */
                       continue;
               default:
                   /* Extended partitions are handled below. */
                       if (MBR_IS_EXTENDED(dp[i].mbrp_type))
                               continue;
                       break;
               }

               memset(&dkw, 0, sizeof(dkw));

               if ((ptype = mbr_ptype_to_str(dp[i].mbrp_type)) == NULL) {
                       /*
                        * XXX Should probably just add these...
                        * XXX maybe just have an empty ptype?
                        */
                       aprint_verbose("%s: skipping partition %d, "
                           "type 0x%02x\n", a->pdk->dk_name, i,
                           dp[i].mbrp_type);
                       continue;
               }
               strlcpy(dkw.dkw_ptype, ptype, sizeof(dkw.dkw_ptype));

               strlcpy(dkw.dkw_parent, a->pdk->dk_name, sizeof(dkw.dkw_parent));
               dkw.dkw_offset = le32toh(dp[i].mbrp_start);
               dkw.dkw_size = le32toh(dp[i].mbrp_size);

               /*
                * These get historical disk naming style
                * wedge names.  We start at 'e', and reserve
                * 4 slots for each MBR we parse.
                *
                * XXX For FAT, we should extract the FAT volume
                * XXX name.
                */
               snprintf(dkw.dkw_wname, sizeof(dkw.dkw_wname),
                   "%s%c", a->pdk->dk_name,
                   'e' + (a->mbr_count * MBR_PART_COUNT) + i);

               error = dkwedge_add(&dkw);
               if (error == EEXIST)
                       aprint_error("%s: wedge named '%s' already "
                           "exists, manual intervention required\n",
                           a->pdk->dk_name, dkw.dkw_wname);
               else if (error)
                       aprint_error("%s: error %d adding partition "
                           "%d type 0x%02x\n", a->pdk->dk_name, error,
                           (a->mbr_count * MBR_PART_COUNT) + i,
                           dp[i].mbrp_type);
       }

       /* We've parsed one MBR. */
       a->mbr_count++;

       /* Recursively scan extended partitions. */
       for (i = 0; i < MBR_PART_COUNT; i++) {
               uint32_t poff;

               if (MBR_IS_EXTENDED(dp[i].mbrp_type)) {
                       poff = le32toh(dp[i].mbrp_start) + extoff;
                       getparts(a, poff, extoff ? extoff : poff);
               }
       }
}

static int
dkwedge_discover_mbr(struct disk *pdk, struct vnode *vp)
{
       mbr_args_t a;

       memset(&a, 0, sizeof(a));
       a.pdk = pdk;
       a.secsize = DEV_BSIZE << pdk->dk_blkshift;
       a.vp = vp;
       a.bp = geteblk(a.secsize);
       a.error = 0;
       a.mbr_count = 0;

       getparts(&a, MBR_BBSECTOR, 0);
       if (a.mbr_count != 0)
               a.error = 0;            /* found it, wedges installed */
       else if (a.error == 0)
               a.error = ESRCH;        /* no MBRs found */

       brelse(a.bp, 0);
       return (a.error);
}

DKWEDGE_DISCOVERY_METHOD_DECL(MBR, 10, dkwedge_discover_mbr);

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