/*      $NetBSD: boot1.c,v 1.22 2023/06/29 14:18:58 manu Exp $  */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by David Laight.
 *
 * 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.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: boot1.c,v 1.22 2023/06/29 14:18:58 manu Exp $");

#include <lib/libsa/stand.h>
#include <lib/libkern/libkern.h>
#include <biosdisk_ll.h>

#include <sys/param.h>
#include <sys/uuid.h>
#include <sys/bootblock.h>
#include <sys/disklabel.h>
#include <sys/disklabel_gpt.h>
#include <dev/raidframe/raidframevar.h> /* For RF_PROTECTED_SECTORS */

#define XSTR(x) #x
#define STR(x) XSTR(x)

static daddr_t bios_sector;

static struct biosdisk_ll d;

const char *boot1(uint32_t, uint64_t *);
#ifndef NO_GPT
static daddr_t gpt_lookup(daddr_t);
#endif
extern void putstr(const char *);

extern struct disklabel ptn_disklabel;

static int
ob(void)
{
        return open("boot", 0);
}

const char *
boot1(uint32_t biosdev, uint64_t *sector)
{
        struct stat sb;
        int fd;

        bios_sector = *sector;
        d.dev = biosdev;

        putstr("\r\nNetBSD/x86 " STR(FS) " Primary Bootstrap\r\n");

        if (set_geometry(&d, NULL))
                return "set_geometry\r\n";

        /*
         * We default to the filesystem at the start of the
         * MBR partition
         */
        fd = ob();
        if (fd != -1)
                goto done;
        /*
         * Maybe the filesystem is enclosed in a raid set.
         * add in size of raidframe header and try again.
         * (Maybe this should only be done if the filesystem
         * magic number is absent.)
         */
        bios_sector += RF_PROTECTED_SECTORS;
        fd = ob();
        if (fd != -1)
                goto done;

#ifndef NO_GPT
        /*
         * Test for a GPT inside the RAID
         */
        bios_sector += gpt_lookup(bios_sector);
        fd = ob();
        if (fd != -1)
                goto done;
#endif

        /*
         * Nothing at the start of the MBR partition, fallback on
         * partition 'a' from the disklabel in this MBR partition.
         */
        if (ptn_disklabel.d_magic != DISKMAGIC ||
            ptn_disklabel.d_magic2 != DISKMAGIC ||
            ptn_disklabel.d_partitions[0].p_fstype == FS_UNUSED)
                goto done;
        bios_sector = ptn_disklabel.d_partitions[0].p_offset;
        *sector = bios_sector;
        if (ptn_disklabel.d_partitions[0].p_fstype == FS_RAID)
                bios_sector += RF_PROTECTED_SECTORS;

        fd = ob();

done:
        if (fd == -1 || fstat(fd, &sb) == -1)
                return "Can't open /boot\r\n";

        biosdev = (uint32_t)sb.st_size;
#if 0
        if (biosdev > SECONDARY_MAX_LOAD)
                return "/boot too large\r\n";
#endif

        if (read(fd, (void *)SECONDARY_LOAD_ADDRESS, biosdev) != biosdev)
                return "/boot load failed\r\n";

        if (*(uint32_t *)(SECONDARY_LOAD_ADDRESS + 4) != X86_BOOT_MAGIC_2)
                return "Invalid /boot file format\r\n";

        /* We need to jump to the secondary bootstrap in realmode */
        return 0;
}

int
blkdevstrategy(void *devdata, int flag, daddr_t dblk, size_t size, void *buf, size_t *rsize)
{
        if (flag != F_READ)
                return EROFS;

        if (size & (BIOSDISK_DEFAULT_SECSIZE - 1))
                return EINVAL;

        if (rsize)
                *rsize = size;

        if (size != 0 && readsects(&d, bios_sector + dblk,
                                   size / BIOSDISK_DEFAULT_SECSIZE,
                                   buf, 1) != 0)
                return EIO;

        return 0;
}

#ifndef NO_GPT
static int
is_unused(struct gpt_ent *ent)
{
        const struct uuid unused = GPT_ENT_TYPE_UNUSED;

        return (memcmp(ent->ent_type, &unused, sizeof(unused)) == 0);
}

static int
is_bootable(struct gpt_ent *ent)
{
        /* GPT_ENT_TYPE_NETBSD_RAID omitted as we are already in a RAID */
        const struct uuid bootable[] = {
                GPT_ENT_TYPE_NETBSD_FFS,
                GPT_ENT_TYPE_NETBSD_LFS,
                GPT_ENT_TYPE_NETBSD_CCD,
                GPT_ENT_TYPE_NETBSD_CGD,
        };
        int i;

        for (i = 0; i < sizeof(bootable) / sizeof(*bootable); i++) {
                if (memcmp(ent->ent_type, &bootable[i],
                    sizeof(struct uuid)) == 0)
                        return 1;
        }

        return 0;
}

static daddr_t
gpt_lookup(daddr_t sector)
{
        char buf[BIOSDISK_DEFAULT_SECSIZE];
        struct mbr_sector *pmbr;        
        const char gpt_hdr_sig[] = GPT_HDR_SIG;
        struct gpt_hdr *hdr;
        struct gpt_ent *ent;
        uint32_t nents;
        uint32_t entsz;
        uint32_t entries_per_sector;
        uint32_t sectors_per_entry;
        uint64_t firstpart_lba = 0;
        uint64_t bootable_lba = 0;
        uint64_t bootme_lba = 0;
        int i, j;

        /*
         * Look for a PMBR
         */
        if (readsects(&d, sector, 1, buf, 1) != 0)
                return 0;

        pmbr = (struct mbr_sector *)buf;

        if (pmbr->mbr_magic != htole16(MBR_MAGIC))
                return 0;

        if (pmbr->mbr_parts[0].mbrp_type != MBR_PTYPE_PMBR)
                return 0;

        sector++; /* skip PMBR */

        /*
         * Look for a GPT header
         * Space is scarce, we do not check CRC.
         */
        if (readsects(&d, sector, 1, buf, 1) != 0)
                return 0;

        hdr = (struct gpt_hdr *)buf;

        if (memcmp(gpt_hdr_sig, hdr->hdr_sig, sizeof(hdr->hdr_sig)) != 0)
                return 0;

        if (hdr->hdr_revision != htole32(GPT_HDR_REVISION))
                return 0;

        if (le32toh(hdr->hdr_size) > BIOSDISK_DEFAULT_SECSIZE)
                return 0;

        nents = le32toh(hdr->hdr_entries);
        entsz = le32toh(hdr->hdr_entsz);

        sector++; /* skip GPT header */

        /*
         * Read partition table
         *
         * According to UEFI specification section 5.3.2, entries
         * are 128 * (2^n) bytes long. The most common scenario is
         * 128 bytes (n = 0) where there are 4 entries per sector.
         * If n > 2, then entries spans multiple sectors, but they
         * remain sector-aligned.
         */
        entries_per_sector = BIOSDISK_DEFAULT_SECSIZE / entsz;
        if (entries_per_sector == 0)
                entries_per_sector = 1;

        sectors_per_entry = entsz / BIOSDISK_DEFAULT_SECSIZE;
        if (sectors_per_entry == 0)
                sectors_per_entry = 1;

        for (i = 0; i < nents; i += entries_per_sector) {
                if (readsects(&d, sector, 1, buf, 1) != 0)
                        return 0;

                sector += sectors_per_entry;

                for (j = 0; j < entries_per_sector; j++) {
                        ent = (struct gpt_ent *)&buf[j * entsz];

                        if (is_unused(ent))
                                continue;

                        /* First bootme wins, we can stop there */
                        if (ent->ent_attr & GPT_ENT_ATTR_BOOTME) {
                                bootme_lba = le64toh(ent->ent_lba_start);
                                goto out;
                        }

                        if (firstpart_lba == 0)
                                firstpart_lba = le64toh(ent->ent_lba_start);

                        if (is_bootable(ent) && bootable_lba == 0)
                                bootable_lba = le64toh(ent->ent_lba_start);
                }
        }

out:
        if (bootme_lba)
                return bootme_lba;

        if (bootable_lba)
                return bootable_lba;

        if (firstpart_lba)
                return firstpart_lba;

        return 0;
}
#endif /* ! NO_GPT */