/*-
 * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * 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 AUTHORS 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 AUTHORS 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/param.h>
#include <sys/gpt.h>

#ifndef LITTLE_ENDIAN
#error gpt.c works only for little endian architectures
#endif

#include "stand.h"
#include "zlib.h"
#include "drv.h"
#include "gpt.h"

static struct gpt_hdr hdr_primary, hdr_backup, *gpthdr;
static uint64_t hdr_primary_lba, hdr_backup_lba;
static struct gpt_ent table_primary[MAXTBLENTS], table_backup[MAXTBLENTS];
static struct gpt_ent *gpttable;
static int curent, bootonce;

/*
 * Buffer below 64kB passed on gptread(), which can hold at least
 * one sector of data (512 bytes).
 */
static char *secbuf;

static void
gptupdate(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
    struct gpt_ent *table)
{
        int entries_per_sec, firstent;
        daddr_t slba;

        /*
         * We need to update the following for both primary and backup GPT:
         * 1. Sector on disk that contains current partition.
         * 2. Partition table checksum.
         * 3. Header checksum.
         * 4. Header on disk.
         */

        entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
        slba = curent / entries_per_sec;
        firstent = slba * entries_per_sec;
        bcopy(&table[firstent], secbuf, DEV_BSIZE);
        slba += hdr->hdr_lba_table;
        if (drvwrite(dskp, secbuf, slba, 1)) {
                printf("%s: unable to update %s GPT partition table\n",
                    BOOTPROG, which);
                return;
        }
        hdr->hdr_crc_table = crc32(0, Z_NULL, 0);
        hdr->hdr_crc_table = crc32(hdr->hdr_crc_table, (const Bytef *)table,
            hdr->hdr_entries * hdr->hdr_entsz);
        hdr->hdr_crc_self = crc32(0, Z_NULL, 0);
        hdr->hdr_crc_self = crc32(hdr->hdr_crc_self, (const Bytef *)hdr,
            hdr->hdr_size);
        bzero(secbuf, DEV_BSIZE);
        bcopy(hdr, secbuf, hdr->hdr_size);
        if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1)) {
                printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
                return;
        }
}

int
gptfind(const uuid_t *uuid, struct dsk *dskp, int part)
{
        struct gpt_ent *ent;
        int firsttry;

        if (part >= 0) {
                if (part == 0 || part > gpthdr->hdr_entries) {
                        printf("%s: invalid partition index\n", BOOTPROG);
                        return (-1);
                }
                ent = &gpttable[part - 1];
                if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0) {
                        printf("%s: specified partition is not UFS\n",
                            BOOTPROG);
                        return (-1);
                }
                curent = part - 1;
                goto found;
        }

        firsttry = (curent == -1);
        curent++;
        if (curent >= gpthdr->hdr_entries) {
                curent = gpthdr->hdr_entries;
                return (-1);
        }
        if (bootonce) {
                /*
                 * First look for partition with both GPT_ENT_ATTR_BOOTME and
                 * GPT_ENT_ATTR_BOOTONCE flags.
                 */
                for (; curent < gpthdr->hdr_entries; curent++) {
                        ent = &gpttable[curent];
                        if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
                                continue;
                        if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
                                continue;
                        if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTONCE))
                                continue;
                        /* Ok, found one. */
                        goto found;
                }
                bootonce = 0;
                curent = 0;
        }
        for (; curent < gpthdr->hdr_entries; curent++) {
                ent = &gpttable[curent];
                if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
                        continue;
                if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
                        continue;
                if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE)
                        continue;
                /* Ok, found one. */
                goto found;
        }
        if (firsttry) {
                /*
                 * No partition with BOOTME flag was found, try to boot from
                 * first UFS partition.
                 */
                for (curent = 0; curent < gpthdr->hdr_entries; curent++) {
                        ent = &gpttable[curent];
                        if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
                                continue;
                        /* Ok, found one. */
                        goto found;
                }
        }
        return (-1);
found:
        dskp->part = curent + 1;
        ent = &gpttable[curent];
        dskp->start = ent->ent_lba_start;
        if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE) {
                /*
                 * Clear BOOTME, but leave BOOTONCE set before trying to
                 * boot from this partition.
                 */
                if (hdr_primary_lba > 0) {
                        table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
                        gptupdate("primary", dskp, &hdr_primary, table_primary);
                }
                if (hdr_backup_lba > 0) {
                        table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
                        gptupdate("backup", dskp, &hdr_backup, table_backup);
                }
        }
        return (0);
}

static int
gptread_hdr(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
    uint64_t hdrlba)
{
        uint32_t crc;

        if (drvread(dskp, secbuf, hdrlba, 1)) {
                printf("%s: unable to read %s GPT header\n", BOOTPROG, which);
                return (-1);
        }
        bcopy(secbuf, hdr, sizeof(*hdr));
        if (bcmp(hdr->hdr_sig, GPT_HDR_SIG, sizeof(hdr->hdr_sig)) != 0 ||
            hdr->hdr_lba_self != hdrlba || hdr->hdr_revision < 0x00010000 ||
            hdr->hdr_entsz < sizeof(struct gpt_ent) ||
            hdr->hdr_entries > MAXTBLENTS || DEV_BSIZE % hdr->hdr_entsz != 0) {
                printf("%s: invalid %s GPT header\n", BOOTPROG, which);
                return (-1);
        }
        crc = hdr->hdr_crc_self;
        hdr->hdr_crc_self = crc32(0, Z_NULL, 0);
        if (crc32(hdr->hdr_crc_self, (const Bytef *)hdr, hdr->hdr_size) !=
            crc) {
                printf("%s: %s GPT header checksum mismatch\n", BOOTPROG,
                    which);
                return (-1);
        }
        hdr->hdr_crc_self = crc;
        return (0);
}

void
gptbootfailed(struct dsk *dskp)
{

        if (!(gpttable[curent].ent_attr & GPT_ENT_ATTR_BOOTONCE))
                return;

        if (hdr_primary_lba > 0) {
                table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
                table_primary[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
                gptupdate("primary", dskp, &hdr_primary, table_primary);
        }
        if (hdr_backup_lba > 0) {
                table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
                table_backup[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
                gptupdate("backup", dskp, &hdr_backup, table_backup);
        }
}

static void
gptbootconv(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
    struct gpt_ent *table)
{
        struct gpt_ent *ent;
        daddr_t slba;
        int table_updated, sector_updated;
        int entries_per_sec, nent, part;

        table_updated = 0;
        entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
        for (nent = 0, slba = hdr->hdr_lba_table;
             slba < hdr->hdr_lba_table + hdr->hdr_entries / entries_per_sec;
             slba++, nent += entries_per_sec) {
                sector_updated = 0;
                for (part = 0; part < entries_per_sec; part++) {
                        ent = &table[nent + part];
                        if ((ent->ent_attr & (GPT_ENT_ATTR_BOOTME |
                            GPT_ENT_ATTR_BOOTONCE |
                            GPT_ENT_ATTR_BOOTFAILED)) !=
                            GPT_ENT_ATTR_BOOTONCE) {
                                continue;
                        }
                        ent->ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
                        ent->ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
                        table_updated = 1;
                        sector_updated = 1;
                }
                if (!sector_updated)
                        continue;
                bcopy(&table[nent], secbuf, DEV_BSIZE);
                if (drvwrite(dskp, secbuf, slba, 1)) {
                        printf("%s: unable to update %s GPT partition table\n",
                            BOOTPROG, which);
                }
        }
        if (!table_updated)
                return;
        hdr->hdr_crc_table = crc32(0, Z_NULL, 0);
        hdr->hdr_crc_table = crc32(hdr->hdr_crc_table, (const Bytef *)table,
            hdr->hdr_entries * hdr->hdr_entsz);
        hdr->hdr_crc_self = crc32(0, Z_NULL, 0);
        hdr->hdr_crc_self = crc32(hdr->hdr_crc_self, (const Bytef *)hdr,
            hdr->hdr_size);
        bzero(secbuf, DEV_BSIZE);
        bcopy(hdr, secbuf, hdr->hdr_size);
        if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1))
                printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
}

static int
gptread_table(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
    struct gpt_ent *table)
{
        struct gpt_ent *ent;
        int entries_per_sec;
        int part, nent;
        daddr_t slba;

        if (hdr->hdr_entries == 0)
                return (0);

        entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
        slba = hdr->hdr_lba_table;
        nent = 0;
        for (;;) {
                if (drvread(dskp, secbuf, slba, 1)) {
                        printf("%s: unable to read %s GPT partition table\n",
                            BOOTPROG, which);
                        return (-1);
                }
                ent = (struct gpt_ent *)secbuf;
                for (part = 0; part < entries_per_sec; part++, ent++) {
                        bcopy(ent, &table[nent], sizeof(table[nent]));
                        if (++nent >= hdr->hdr_entries)
                                break;
                }
                if (nent >= hdr->hdr_entries)
                        break;
                slba++;
        }
        if (crc32(0, (const Bytef *)table, nent * hdr->hdr_entsz) !=
            hdr->hdr_crc_table) {
                printf("%s: %s GPT table checksum mismatch\n", BOOTPROG, which);
                return (-1);
        }
        return (0);
}

int
gptread(struct dsk *dskp, char *buf)
{
        uint64_t altlba;

        /*
         * Read and verify both GPT headers: primary and backup.
         */

        secbuf = buf;
        hdr_primary_lba = hdr_backup_lba = 0;
        curent = -1;
        bootonce = 1;
        dskp->start = 0;

        if (gptread_hdr("primary", dskp, &hdr_primary, 1) == 0 &&
            gptread_table("primary", dskp, &hdr_primary, table_primary) == 0) {
                hdr_primary_lba = hdr_primary.hdr_lba_self;
                gpthdr = &hdr_primary;
                gpttable = table_primary;
        }

        if (hdr_primary_lba > 0) {
                /*
                 * If primary header is valid, we can get backup
                 * header location from there.
                 */
                altlba = hdr_primary.hdr_lba_alt;
        } else {
                altlba = drvsize(dskp);
                if (altlba > 0)
                        altlba--;
        }
        if (altlba == 0)
                printf("%s: unable to locate backup GPT header\n", BOOTPROG);
        else if (gptread_hdr("backup", dskp, &hdr_backup, altlba) == 0 &&
            gptread_table("backup", dskp, &hdr_backup, table_backup) == 0) {
                hdr_backup_lba = hdr_backup.hdr_lba_self;
                if (hdr_primary_lba == 0) {
                        gpthdr = &hdr_backup;
                        gpttable = table_backup;
                        printf("%s: using backup GPT\n", BOOTPROG);
                }
        }

        /*
         * Convert all BOOTONCE without BOOTME flags into BOOTFAILED.
         * BOOTONCE without BOOTME means that we tried to boot from it,
         * but failed after leaving gptboot and machine was rebooted.
         * We don't want to leave partitions marked as BOOTONCE only,
         * because when we boot successfully start-up scripts should
         * find at most one partition with only BOOTONCE flag and this
         * will mean that we booted from that partition.
         */
        if (hdr_primary_lba != 0)
                gptbootconv("primary", dskp, &hdr_primary, table_primary);
        if (hdr_backup_lba != 0)
                gptbootconv("backup", dskp, &hdr_backup, table_backup);

        if (hdr_primary_lba == 0 && hdr_backup_lba == 0)
                return (-1);
        return (0);
}