/*      $NetBSD: dkwedge_gpt.c,v 1.26 2020/04/11 16:00:34 jdolecek 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.
*/

/*
* EFI GUID Partition Table support for disk wedges
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dkwedge_gpt.c,v 1.26 2020/04/11 16:00:34 jdolecek 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/disklabel_gpt.h>
#include <sys/uuid.h>

/* UTF-8 encoding stuff */
#include <fs/unicode.h>

/*
* GUID to dkw_ptype mapping information.
*
* GPT_ENT_TYPE_MS_BASIC_DATA is not suited to mapping.  Aside from being
* used for multiple Microsoft file systems, Linux uses it for its own
* set of native file systems.  Treating this GUID as unknown seems best.
*/

static const struct {
       struct uuid ptype_guid;
       const char *ptype_str;
} gpt_ptype_guid_to_str_tab[] = {
       { GPT_ENT_TYPE_EFI,                     DKW_PTYPE_FAT },
       { GPT_ENT_TYPE_NETBSD_SWAP,             DKW_PTYPE_SWAP },
       { GPT_ENT_TYPE_FREEBSD_SWAP,            DKW_PTYPE_SWAP },
       { GPT_ENT_TYPE_NETBSD_FFS,              DKW_PTYPE_FFS },
       { GPT_ENT_TYPE_FREEBSD_UFS,             DKW_PTYPE_FFS },
       { GPT_ENT_TYPE_APPLE_UFS,               DKW_PTYPE_FFS },
       { GPT_ENT_TYPE_NETBSD_LFS,              DKW_PTYPE_LFS },
       { GPT_ENT_TYPE_NETBSD_RAIDFRAME,        DKW_PTYPE_RAIDFRAME },
       { GPT_ENT_TYPE_NETBSD_CCD,              DKW_PTYPE_CCD },
       { GPT_ENT_TYPE_NETBSD_CGD,              DKW_PTYPE_CGD },
       { GPT_ENT_TYPE_APPLE_HFS,               DKW_PTYPE_APPLEHFS },
       { GPT_ENT_TYPE_VMWARE_VMKCORE,          DKW_PTYPE_VMKCORE },
       { GPT_ENT_TYPE_VMWARE_VMFS,             DKW_PTYPE_VMFS },
       { GPT_ENT_TYPE_VMWARE_RESERVED,         DKW_PTYPE_VMWRESV },
       { GPT_ENT_TYPE_MS_BASIC_DATA,           DKW_PTYPE_NTFS },
       { GPT_ENT_TYPE_LINUX_DATA,              DKW_PTYPE_EXT2FS },
       { GPT_ENT_TYPE_FREEBSD_ZFS,             DKW_PTYPE_ZFS },
};

static const char *
gpt_ptype_guid_to_str(const struct uuid *guid)
{
       int i;

       for (i = 0; i < __arraycount(gpt_ptype_guid_to_str_tab); i++) {
               if (memcmp(&gpt_ptype_guid_to_str_tab[i].ptype_guid,
                          guid, sizeof(*guid)) == 0)
                       return (gpt_ptype_guid_to_str_tab[i].ptype_str);
       }

       return (DKW_PTYPE_UNKNOWN);
}

static int
gpt_verify_header_crc(struct gpt_hdr *hdr)
{
       uint32_t crc;
       int rv;

       crc = hdr->hdr_crc_self;
       hdr->hdr_crc_self = 0;
       rv = le32toh(crc) == crc32(0, (void *)hdr, le32toh(hdr->hdr_size));
       hdr->hdr_crc_self = crc;

       return (rv);
}

static int
dkwedge_discover_gpt(struct disk *pdk, struct vnode *vp)
{
       static const struct uuid ent_type_unused = GPT_ENT_TYPE_UNUSED;
       static const char gpt_hdr_sig[] = GPT_HDR_SIG;
       struct dkwedge_info dkw;
       struct buf *bp;
       uint32_t secsize;
       struct gpt_hdr *hdr;
       struct gpt_ent *ent;
       uint32_t entries, entsz;
       daddr_t lba_start, lba_end, lba_table;
       uint32_t gpe_crc;
       int error;
       u_int i;
       size_t r, n, sz;
       uint8_t *c;

       secsize = DEV_BSIZE << pdk->dk_blkshift;
       bp = geteblk(secsize);

       /*
        * Note: We don't bother with a Legacy or Protective MBR
        * here.  If a GPT is found, then the search stops, and
        * the GPT is authoritative.
        */

       /* Read in the GPT Header. */
       error = dkwedge_read(pdk, vp, GPT_HDR_BLKNO << pdk->dk_blkshift,
           bp->b_data, secsize);
       if (error)
               goto out;
       hdr = bp->b_data;

       /* Validate it. */
       if (memcmp(gpt_hdr_sig, hdr->hdr_sig, sizeof(hdr->hdr_sig)) != 0) {
               /* XXX Should check at end-of-disk. */
               error = ESRCH;
               goto out;
       }
       if (hdr->hdr_revision != htole32(GPT_HDR_REVISION)) {
               /* XXX Should check at end-of-disk. */
               error = ESRCH;
               goto out;
       }
       if (le32toh(hdr->hdr_size) > secsize) {
               /* XXX Should check at end-of-disk. */
               error = ESRCH;
               goto out;
       }
       if (gpt_verify_header_crc(hdr) == 0) {
               /* XXX Should check at end-of-disk. */
               error = ESRCH;
               goto out;
       }

       /* XXX Now that we found it, should we validate the backup? */

       {
               struct uuid disk_guid;
               char guid_str[UUID_STR_LEN];
               uuid_dec_le(hdr->hdr_guid, &disk_guid);
               uuid_snprintf(guid_str, sizeof(guid_str), &disk_guid);
               aprint_verbose("%s: GPT GUID: %s\n", pdk->dk_name, guid_str);
       }

       entries = le32toh(hdr->hdr_entries);
       entsz = roundup(le32toh(hdr->hdr_entsz), 8);
       if (entsz != sizeof(struct gpt_ent)) {
               aprint_error("%s: bogus GPT entry size: %u\n",
                   pdk->dk_name, le32toh(hdr->hdr_entsz));
               error = EINVAL;
               goto out;
       }
       gpe_crc = le32toh(hdr->hdr_crc_table);

       /* XXX Clamp entries at 512 for now. */
       if (entries > 512) {
               aprint_error("%s: WARNING: clamping number of GPT entries to "
                   "512 (was %u)\n", pdk->dk_name, entries);
               entries = 512;
       }

       lba_start = le64toh(hdr->hdr_lba_start);
       lba_end = le64toh(hdr->hdr_lba_end);
       lba_table = le64toh(hdr->hdr_lba_table);
       if (lba_start < 0 || lba_end < 0 || lba_table < 0) {
               aprint_error("%s: GPT block numbers out of range\n",
                   pdk->dk_name);
               error = EINVAL;
               goto out;
       }

       brelse(bp, 0);

       sz = roundup(entries * entsz, secsize);
       bp = geteblk(sz);
       error = dkwedge_read(pdk, vp, lba_table << pdk->dk_blkshift,
           bp->b_data, sz);
       if (error) {
               /* XXX Should check alternate location. */
               aprint_error("%s: unable to read GPT partition array, "
                   "error = %d\n", pdk->dk_name, error);
               goto out;
       }

       if (crc32(0, bp->b_data, entries * entsz) != gpe_crc) {
               /* XXX Should check alternate location. */
               aprint_error("%s: bad GPT partition array CRC\n",
                   pdk->dk_name);
               error = EINVAL;
               goto out;
       }

       /*
        * Walk the partitions, adding a wedge for each type we know about.
        */
       for (i = 0; i < entries; i++) {
               struct uuid ptype_guid, ent_guid;
               const char *ptype;
               int j;
               char ptype_guid_str[UUID_STR_LEN], ent_guid_str[UUID_STR_LEN];

               ent = (struct gpt_ent *)((char *)bp->b_data + (i * entsz));

               uuid_dec_le(ent->ent_type, &ptype_guid);
               if (memcmp(&ptype_guid, &ent_type_unused,
                          sizeof(ptype_guid)) == 0)
                       continue;

               uuid_dec_le(ent->ent_guid, &ent_guid);

               uuid_snprintf(ptype_guid_str, sizeof(ptype_guid_str),
                   &ptype_guid);
               uuid_snprintf(ent_guid_str, sizeof(ent_guid_str),
                   &ent_guid);

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

               /* figure out the type */
               ptype = gpt_ptype_guid_to_str(&ptype_guid);
               strlcpy(dkw.dkw_ptype, ptype, sizeof(dkw.dkw_ptype));

               strlcpy(dkw.dkw_parent, pdk->dk_name, sizeof(dkw.dkw_parent));
               dkw.dkw_offset = le64toh(ent->ent_lba_start);
               dkw.dkw_size = le64toh(ent->ent_lba_end) - dkw.dkw_offset + 1;

               /* XXX Make sure it falls within the disk's data area. */

               if (ent->ent_name[0] == 0x0000)
                       strlcpy(dkw.dkw_wname, ent_guid_str, sizeof(dkw.dkw_wname));
               else {
                       c = dkw.dkw_wname;
                       r = sizeof(dkw.dkw_wname) - 1;
                       for (j = 0; j < __arraycount(ent->ent_name)
                           && ent->ent_name[j] != 0x0000; j++) {
                               n = wput_utf8(c, r, le16toh(ent->ent_name[j]));
                               if (n == 0)
                                       break;
                               c += n; r -= n;
                       }
                       *c = '\0';
               }

               /*
                * Try with the partition name first.  If that fails,
                * use the GUID string.  If that fails, punt.
                */
               if ((error = dkwedge_add(&dkw)) == EEXIST &&
                   strcmp(dkw.dkw_wname, ent_guid_str) != 0) {
                       char orig[sizeof(dkw.dkw_wname)];
                       strlcpy(orig, dkw.dkw_wname, sizeof(orig));
                       strlcpy(dkw.dkw_wname, ent_guid_str, sizeof(dkw.dkw_wname));
                       error = dkwedge_add(&dkw);
                       if (!error)
                               aprint_error("%s: wedge named '%s' already "
                                   "existed, using '%s'\n", pdk->dk_name,
                                   orig, ent_guid_str);
               }
               if (error == EEXIST)
                       aprint_error("%s: wedge named '%s' already exists, "
                           "manual intervention required\n", pdk->dk_name,
                           dkw.dkw_wname);
               else if (error)
                       aprint_error("%s: error %d adding entry %u (%s), "
                           "type %s\n", pdk->dk_name, error, i, ent_guid_str,
                           ptype_guid_str);
       }
       error = 0;

out:
       brelse(bp, 0);
       return (error);
}

DKWEDGE_DISCOVERY_METHOD_DECL(GPT, 0, dkwedge_discover_gpt);

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