/*-
 * Copyright (c) 1994 Bruce D. Evans.
 * All rights reserved.
 *
 * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      from: @(#)ufs_disksubr.c        7.16 (Berkeley) 5/4/91
 *      from: ufs_disksubr.c,v 1.8 1994/06/07 01:21:39 phk Exp $
 * $FreeBSD: src/sys/kern/subr_diskmbr.c,v 1.45 2000/01/28 10:22:07 bde Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/diskslice.h>
#include <sys/diskmbr.h>
#include <sys/disk.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/device.h>

#define TRACE(str)      do { if (dsi_debug) kprintf str; } while (0)

static volatile u_char dsi_debug;

/*
 * This is what we have embedded in every boot1 for supporting the bogus
 * "Dangerously Dedicated" mode. However, the old table is broken because
 * it has an illegal geometry in it - it specifies 256 heads (heads = end
 * head + 1) which causes nasty stuff when that wraps to zero in bios code.
 * eg: divide by zero etc. This caused the dead-thinkpad problem, numerous
 * SCSI bios crashes, EFI to crash, etc.
 *
 * We still have to recognize the old table though, even though we stopped
 * inflicting it upon the world.
 */
static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0x80, 0, 1, 0, DOSPTYP_DFLYBSD, 255, 255, 255, 0, 50000, },
};
static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
        { 0x80, 0, 1, 0, DOSPTYP_DFLYBSD, 254, 255, 255, 0, 50000, },
};

static int check_part (char *sname, struct dos_partition *dp,
                           u_int64_t offset, int nsectors, int ntracks,
                           u_int64_t mbr_offset);
static void mbr_extended (cdev_t dev, struct disk_info *info,
                              struct diskslices *ssp, u_int64_t ext_offset,
                              u_int64_t ext_size, u_int64_t base_ext_offset,
                              int nsectors, int ntracks, u_int64_t mbr_offset,
                              int level);
static int mbr_setslice (char *sname, struct disk_info *info,
                             struct diskslice *sp, struct dos_partition *dp,
                             u_int64_t br_offset);


int
mbrinit(cdev_t dev, struct disk_info *info, struct diskslices **sspp)
{
        struct buf *bp;
        u_char  *cp;
        int     dospart;
        struct dos_partition *dp;
        struct dos_partition *dp0;
        struct dos_partition dpcopy[NDOSPART];
        int     error;
        int     max_ncyls;
        int     max_nsectors;
        int     max_ntracks;
        u_int64_t mbr_offset;
        char    partname[2];
        u_long  secpercyl;
        char    *sname;
        struct diskslice *sp;
        struct diskslices *ssp;
        cdev_t wdev;

        error = 0;
        sname = dsname(dev, 0, 0, 0, NULL);
        mbr_offset = DOSBBSECTOR;
reread_mbr:
        /*
         * Don't bother if the block size is weird or the
         * media size is 0 (probably means no media present).
         */
        if (info->d_media_blksize & DEV_BMASK)
                return (EIO);
        if (info->d_media_size == 0)
                return (EIO);

        /*
         * Read master boot record.
         */
        wdev = dev;
        bp = getpbuf_mem(NULL);
        KKASSERT((int)info->d_media_blksize <= bp->b_bufsize);
        bp->b_bio1.bio_offset = (off_t)mbr_offset * info->d_media_blksize;
        bp->b_bio1.bio_done = biodone_sync;
        bp->b_bio1.bio_flags |= BIO_SYNC;
        bp->b_bcount = info->d_media_blksize;
        bp->b_cmd = BUF_CMD_READ;
        bp->b_flags |= B_FAILONDIS;
        dev_dstrategy(wdev, &bp->b_bio1);
        if (biowait(&bp->b_bio1, "mbrrd") != 0) {
                if ((info->d_dsflags & DSO_MBRQUIET) == 0) {
                        diskerr(&bp->b_bio1, wdev,
                                "reading primary partition table: error",
                                LOG_PRINTF, 0);
                        kprintf("\n");
                }
                error = EIO;
                goto done;
        }

        /* Weakly verify it. */
        cp = bp->b_data;
        if (cp[0x1FE] != 0x55 || cp[0x1FF] != 0xAA) {
                /* Don't complain MBR missing for device mapper and CD. */
                if ((info->d_dsflags & (DSO_DEVICEMAPPER | DSO_COMPATLABEL |
                                        DSO_COMPATPARTA)) == 0) {
                        kprintf("%s: MBR magic not found; "
                                "assume a COMPATIBILITY_SLICE (s0)\n", sname);
                }
                goto done;
        }

        /* Make a copy of the partition table to avoid alignment problems. */
        memcpy(&dpcopy[0], cp + DOSPARTOFF, sizeof(dpcopy));
        dp0 = &dpcopy[0];

        /*
         * Check for "Ontrack Disk Manager" or GPT.
         *
         * If a GPT is found in the first DOS partition, ignore the rest of the
         * MBR and go to GPT processing.
         */
        for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
                if (dospart == 0 && dp->dp_typ == DOSPTYP_PMBR) {
                        if (bootverbose)
                                kprintf("%s: Found GPT in slice #%d\n",
                                        sname, dospart + 1);
                        error = gptinit(dev, info, sspp);
                        goto done;
                }

                if (dp->dp_typ == DOSPTYP_ONTRACK) {
                        if (bootverbose)
                                kprintf("%s: Found \"Ontrack Disk Manager\" "
                                        "on this disk.\n", sname);
                        bp->b_flags |= B_INVAL | B_AGE;
                        brelse(bp);
                        mbr_offset = 63;
                        goto reread_mbr;
                }
        }

        if (bcmp(dp0, historical_bogus_partition_table,
                 sizeof historical_bogus_partition_table) == 0 ||
            bcmp(dp0, historical_bogus_partition_table_fixed,
                 sizeof historical_bogus_partition_table_fixed) == 0)
        {
#if 0
                TRACE(("%s: invalid primary partition table: historical\n",
                       sname));
#endif /* 0 */
                if (bootverbose)
                        kprintf("%s: invalid primary partition table: "
                                "Dangerously Dedicated (ignored)\n", sname);
                error = EINVAL;
                goto done;
        }

        /* Guess the geometry. */
        /*
         * TODO:
         * Perhaps skip entries with 0 size.
         * Perhaps only look at entries of type DOSPTYP_386BSD or
         * DOSPTYP_DFLYBSD
         */
        max_ncyls = 0;
        max_nsectors = 0;
        max_ntracks = 0;
        for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
                int     ncyls;
                int     nsectors;
                int     ntracks;

                ncyls = DPCYL(dp->dp_ecyl, dp->dp_esect) + 1;
                if (max_ncyls < ncyls)
                        max_ncyls = ncyls;
                nsectors = DPSECT(dp->dp_esect);
                if (max_nsectors < nsectors)
                        max_nsectors = nsectors;
                ntracks = dp->dp_ehd + 1;
                if (max_ntracks < ntracks)
                        max_ntracks = ntracks;
        }

        /*
         * Check that we have guessed the geometry right by checking the
         * partition entries.
         */
        /*
         * TODO:
         * As above.
         * Check for overlaps.
         * Check against d_secperunit if the latter is reliable.
         */
        for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
                if (dp->dp_scyl == 0 && dp->dp_shd == 0 && dp->dp_ssect == 0
                    && dp->dp_start == 0 && dp->dp_size == 0)
                        continue;
                //sname = dsname(dev, dkunit(dev), BASE_SLICE + dospart,
                //             WHOLE_SLICE_PART, partname);

                /*
                 * Temporarily ignore errors from this check.  We could
                 * simplify things by accepting the table eariler if we
                 * always ignore errors here.  Perhaps we should always
                 * accept the table if the magic is right but not let
                 * bad entries affect the geometry.
                 */
                check_part(sname, dp, mbr_offset, max_nsectors, max_ntracks,
                           mbr_offset);
        }
        if (error != 0)
                goto done;

        /*
         * Accept the DOS partition table.
         *
         * Adjust the disk information structure with updated CHS
         * conversion parameters, but only use values extracted from
         * the primary partition table.
         *
         * NOTE!  Regardless of our having to deal with this old cruft,
         * we do not screw around with the info->d_media* parameters.
         */
        secpercyl = (u_long)max_nsectors * max_ntracks;
        if (secpercyl != 0 && mbr_offset == DOSBBSECTOR) {
                info->d_secpertrack = max_nsectors;
                info->d_nheads = max_ntracks;
                info->d_secpercyl = secpercyl;
                info->d_ncylinders = info->d_media_blocks / secpercyl;
        }

        /*
         * We are passed a pointer to a suitably initialized minimal
         * slices "struct" with no dangling pointers in it.  Replace it
         * by a maximal one.  This usually oversizes the "struct", but
         * enlarging it while searching for logical drives would be
         * inconvenient.
         */
        kfree(*sspp, M_DEVBUF);
        ssp = dsmakeslicestruct(MAX_SLICES, info);
        *sspp = ssp;

        /* Initialize normal slices. */
        sp = &ssp->dss_slices[BASE_SLICE];
        for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++, sp++) {
                sname = dsname(dev, dkunit(dev), BASE_SLICE + dospart,
                               WHOLE_SLICE_PART, partname);
                (void)mbr_setslice(sname, info, sp, dp, mbr_offset);
        }
        ssp->dss_nslices = BASE_SLICE + NDOSPART;

        /* Handle extended partitions. */
        sp -= NDOSPART;
        for (dospart = 0; dospart < NDOSPART; dospart++, sp++) {
                if (sp->ds_type == DOSPTYP_EXT ||
                    sp->ds_type == DOSPTYP_EXTLBA) {
                        mbr_extended(wdev, info, ssp,
                                     sp->ds_offset, sp->ds_size, sp->ds_offset,
                                     max_nsectors, max_ntracks, mbr_offset, 1);
                }
        }

        /*
         * mbr_extended() abuses ssp->dss_nslices for the number of slices
         * that would be found if there were no limit on the number of slices
         * in *ssp.  Cut it back now.
         */
        if (ssp->dss_nslices > MAX_SLICES)
                ssp->dss_nslices = MAX_SLICES;

done:
        bp->b_flags |= B_INVAL | B_AGE;
        relpbuf(bp, NULL);
        return (error);
}

static int
check_part(char *sname, struct dos_partition *dp, u_int64_t offset,
            int nsectors, int ntracks, u_int64_t mbr_offset)
{
        int     chs_ecyl;
        int     chs_esect;
        int     chs_scyl;
        int     chs_ssect;
        int     error;
        u_long  secpercyl;
        u_int64_t esector;
        u_int64_t esector1;
        u_int64_t ssector;
        u_int64_t ssector1;

        secpercyl = (u_long)nsectors * ntracks;
        chs_scyl = DPCYL(dp->dp_scyl, dp->dp_ssect);
        chs_ssect = DPSECT(dp->dp_ssect);
        ssector = chs_ssect - 1 + dp->dp_shd * nsectors + chs_scyl * secpercyl
                  + mbr_offset;
        ssector1 = offset + dp->dp_start;

        /*
         * If ssector1 is on a cylinder >= 1024, then ssector can't be right.
         * Allow the C/H/S for it to be 1023/ntracks-1/nsectors, or correct
         * apart from the cylinder being reduced modulo 1024.  Always allow
         * 1023/255/63, because this is the official way to represent
         * pure-LBA for the starting position.
         */
        if ((ssector < ssector1
             && ((chs_ssect == nsectors && dp->dp_shd == ntracks - 1
                  && chs_scyl == 1023)
                 || (secpercyl != 0
                     && (ssector1 - ssector) % (1024 * secpercyl) == 0)))
            || (dp->dp_scyl == 255 && dp->dp_shd == 255
                && dp->dp_ssect == 255))
        {
                TRACE(("%s: C/H/S start %d/%d/%d, start %llu: allow\n",
                       sname, chs_scyl, dp->dp_shd, chs_ssect,
                       (long long)ssector1));
                ssector = ssector1;
        }

        chs_ecyl = DPCYL(dp->dp_ecyl, dp->dp_esect);
        chs_esect = DPSECT(dp->dp_esect);
        esector = chs_esect - 1 + dp->dp_ehd * nsectors + chs_ecyl * secpercyl
                  + mbr_offset;
        esector1 = ssector1 + dp->dp_size - 1;

        /*
         * Allow certain bogus C/H/S values for esector, as above. However,
         * heads == 255 isn't really legal and causes some BIOS crashes. The
         * correct value to indicate a pure-LBA end is 1023/heads-1/sectors -
         * usually 1023/254/63. "heads" is base 0, "sectors" is base 1.
         */
        if ((esector < esector1
             && ((chs_esect == nsectors && dp->dp_ehd == ntracks - 1
                  && chs_ecyl == 1023)
                 || (secpercyl != 0
                     && (esector1 - esector) % (1024 * secpercyl) == 0)))
            || (dp->dp_ecyl == 255 && dp->dp_ehd == 255
                && dp->dp_esect == 255))
        {
                TRACE(("%s: C/H/S end %d/%d/%d, end %llu: allow\n",
                       sname, chs_ecyl, dp->dp_ehd, chs_esect,
                       (long long)esector1));
                esector = esector1;
        }

        error = (ssector == ssector1 && esector == esector1) ? 0 : EINVAL;
        if (bootverbose) {
                kprintf("%s: type 0x%x, start %llu, end = %llu, size %u %s\n",
                        sname, dp->dp_typ,
                        (long long)ssector1, (long long)esector1,
                        dp->dp_size, (error ? "" : ": OK"));
                if (ssector != ssector1)
                        kprintf("%s: C/H/S start %d/%d/%d (%llu) != start %llu"
                                ": invalid\n",
                                sname, chs_scyl, dp->dp_shd, chs_ssect,
                                (long long)ssector, (long long)ssector1);
                if (esector != esector1)
                        kprintf("%s: C/H/S end %d/%d/%d (%llu) != end %llu"
                                ": invalid\n",
                                sname, chs_ecyl, dp->dp_ehd, chs_esect,
                                (long long)esector, (long long)esector1);
        }

        return (error);
}

static void
mbr_extended(cdev_t dev, struct disk_info *info, struct diskslices *ssp,
            u_int64_t ext_offset, u_int64_t ext_size, u_int64_t base_ext_offset,
            int nsectors, int ntracks, u_int64_t mbr_offset, int level)
{
        struct buf *bp;
        u_char  *cp;
        int     dospart;
        struct dos_partition *dp;
        struct dos_partition dpcopy[NDOSPART];
        u_int64_t ext_offsets[NDOSPART];
        u_int64_t ext_sizes[NDOSPART];
        char    partname[2];
        int     slice;
        char    *sname;
        struct diskslice *sp;

        if (level >= 16) {
                kprintf("%s: excessive recursion in search for slices; "
                        "aborting search\n", devtoname(dev));
                return;
        }

        /* Read extended boot record. */
        bp = getpbuf_mem(NULL);
        KKASSERT((int)info->d_media_blksize <= bp->b_bufsize);
        bp->b_bio1.bio_offset = (off_t)ext_offset * info->d_media_blksize;
        bp->b_bio1.bio_done = biodone_sync;
        bp->b_bio1.bio_flags |= BIO_SYNC;
        bp->b_bcount = info->d_media_blksize;
        bp->b_cmd = BUF_CMD_READ;
        bp->b_flags |= B_FAILONDIS;
        dev_dstrategy(dev, &bp->b_bio1);
        if (biowait(&bp->b_bio1, "mbrrd") != 0) {
                diskerr(&bp->b_bio1, dev,
                        "reading extended partition table: error",
                        LOG_PRINTF, 0);
                kprintf("\n");
                goto done;
        }

        /* Weakly verify it. */
        cp = bp->b_data;
        if (cp[0x1FE] != 0x55 || cp[0x1FF] != 0xAA) {
                sname = dsname(dev, dkunit(dev), WHOLE_DISK_SLICE, WHOLE_SLICE_PART,
                               partname);
                if (bootverbose)
                        kprintf("%s: invalid extended partition table: no magic\n",
                                sname);
                goto done;
        }

        /* Make a copy of the partition table to avoid alignment problems. */
        memcpy(&dpcopy[0], cp + DOSPARTOFF, sizeof(dpcopy));

        slice = ssp->dss_nslices;
        for (dospart = 0, dp = &dpcopy[0]; dospart < NDOSPART;
            dospart++, dp++) {
                ext_sizes[dospart] = 0;
                if (dp->dp_scyl == 0 && dp->dp_shd == 0 && dp->dp_ssect == 0
                    && dp->dp_start == 0 && dp->dp_size == 0)
                        continue;
                if (dp->dp_typ == DOSPTYP_EXT ||
                    dp->dp_typ == DOSPTYP_EXTLBA) {
                        static char buf[32];

                        sname = dsname(dev, dkunit(dev), WHOLE_DISK_SLICE,
                                       WHOLE_SLICE_PART, partname);
                        ksnprintf(buf, sizeof(buf), "%s", sname);
                        if (strlen(buf) < sizeof buf - 11)
                                strcat(buf, "<extended>");
                        check_part(buf, dp, base_ext_offset, nsectors,
                                   ntracks, mbr_offset);
                        ext_offsets[dospart] = base_ext_offset + dp->dp_start;
                        ext_sizes[dospart] = dp->dp_size;
                } else {
                        sname = dsname(dev, dkunit(dev), slice, WHOLE_SLICE_PART,
                                       partname);
                        check_part(sname, dp, ext_offset, nsectors, ntracks,
                                   mbr_offset);
                        if (slice >= MAX_SLICES) {
                                kprintf("%s: too many slices\n", sname);
                                slice++;
                                continue;
                        }
                        sp = &ssp->dss_slices[slice];
                        if (mbr_setslice(sname, info, sp, dp, ext_offset) != 0)
                                continue;
                        slice++;
                }
        }
        ssp->dss_nslices = slice;

        /* If we found any more slices, recursively find all the subslices. */
        for (dospart = 0; dospart < NDOSPART; dospart++) {
                if (ext_sizes[dospart] != 0) {
                        mbr_extended(dev, info, ssp, ext_offsets[dospart],
                                     ext_sizes[dospart], base_ext_offset,
                                     nsectors, ntracks, mbr_offset, ++level);
                }
        }

done:
        bp->b_flags |= B_INVAL | B_AGE;
        relpbuf(bp, NULL);
}

static int
mbr_setslice(char *sname, struct disk_info *info, struct diskslice *sp,
            struct dos_partition *dp, u_int64_t br_offset)
{
        u_int64_t       offset;
        u_int64_t       size;

        offset = br_offset + dp->dp_start;
        if (offset > info->d_media_blocks || offset < br_offset) {
                kprintf(
                "%s: slice starts beyond end of the disk: rejecting it\n",
                       sname);
                return (1);
        }
        size = info->d_media_blocks - offset;
        if (size >= dp->dp_size) {
                if (dp->dp_size == 0xFFFFFFFFU) {
                        kprintf("%s: slice >2TB, using media size instead "
                                "of slice table size\n", sname);
                } else {
                        size = dp->dp_size;
                }
        } else {
                kprintf("%s: slice extends beyond end of disk: "
                        "truncating from %u to %llu sectors\n",
                        sname, dp->dp_size, (unsigned long long)size);
        }
        sp->ds_offset = offset;
        sp->ds_size = size;
        sp->ds_type = dp->dp_typ;
        bzero(&sp->ds_type_uuid, sizeof(sp->ds_type_uuid));
        bzero(&sp->ds_stor_uuid, sizeof(sp->ds_type_uuid));

        /*
         * Slices do not overlap with the parent (if any).
         */
        sp->ds_reserved = 0;
        return (0);
}