libfdisk: provide more details about GPT

[thirdparty/util-linux.git] / libfdisk / src / gpt.c

/*
 * Copyright (C) 2007 Karel Zak <kzak@redhat.com>
 * Copyright (C) 2012 Davidlohr Bueso <dave@gnu.org>
 *
 * GUID Partition Table (GPT) support. Based on UEFI Specs 2.3.1
 * Chapter 5: GUID Partition Table (GPT) Disk Layout (Jun 27th, 2012).
 * Some ideas and inspiration from GNU parted and gptfdisk.
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
#include <uuid.h>

#include "fdiskP.h"

#include "nls.h"
#include "crc32.h"
#include "blkdev.h"
#include "bitops.h"
#include "strutils.h"
#include "all-io.h"

#define GPT_HEADER_SIGNATURE 0x5452415020494645LL /* EFI PART */
#define GPT_HEADER_REVISION_V1_02 0x00010200
#define GPT_HEADER_REVISION_V1_00 0x00010000
#define GPT_HEADER_REVISION_V0_99 0x00009900
#define GPT_HEADER_MINSZ          92 /* bytes */

#define GPT_PMBR_LBA        0
#define GPT_MBR_PROTECTIVE  1
#define GPT_MBR_HYBRID      2

#define GPT_PRIMARY_PARTITION_TABLE_LBA 0x00000001

#define EFI_PMBR_OSTYPE     0xEE
#define MSDOS_MBR_SIGNATURE 0xAA55
#define GPT_PART_NAME_LEN   72 / sizeof(uint16_t)
#define GPT_NPARTITIONS     128

/* Globally unique identifier */
struct gpt_guid {
        uint32_t   time_low;
        uint16_t   time_mid;
        uint16_t   time_hi_and_version;
        uint8_t    clock_seq_hi;
        uint8_t    clock_seq_low;
        uint8_t    node[6];
};


/* only checking that the GUID is 0 is enough to verify an empty partition. */
#define GPT_UNUSED_ENTRY_GUID                                           \
        ((struct gpt_guid) { 0x00000000, 0x0000, 0x0000, 0x00, 0x00,    \
                             { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }})

/* Linux native partition type */
#define GPT_DEFAULT_ENTRY_TYPE "0FC63DAF-8483-4772-8E79-3D69D8477DE4"

/*
 * Attribute bits
 */
struct gpt_attr {
        uint64_t            required_to_function:1;
        uint64_t            no_blockio_protocol:1;
        uint64_t            legacy_bios_bootable:1;
        uint64_t            reserved:45;
        uint64_t            guid_secific:16;
}  __attribute__ ((packed));

/* The GPT Partition entry array contains an array of GPT entries. */
struct gpt_entry {
        struct gpt_guid     type; /* purpose and type of the partition */
        struct gpt_guid     partition_guid;
        uint64_t            lba_start;
        uint64_t            lba_end;
        struct gpt_attr     attr;
        uint16_t            name[GPT_PART_NAME_LEN];
}  __attribute__ ((packed));

/* GPT header */
struct gpt_header {
        uint64_t            signature; /* header identification */
        uint32_t            revision; /* header version */
        uint32_t            size; /* in bytes */
        uint32_t            crc32; /* header CRC checksum */
        uint32_t            reserved1; /* must be 0 */
        uint64_t            my_lba; /* LBA that contains this struct (LBA 1) */
        uint64_t            alternative_lba; /* backup GPT header */
        uint64_t            first_usable_lba; /* first usable logical block for partitions */
        uint64_t            last_usable_lba; /* last usable logical block for partitions */
        struct gpt_guid     disk_guid; /* unique disk identifier */
        uint64_t            partition_entry_lba; /* stat LBA of the partition entry array */
        uint32_t            npartition_entries; /* total partition entries - normally 128 */
        uint32_t            sizeof_partition_entry; /* bytes for each GUID pt */
        uint32_t            partition_entry_array_crc32; /* partition CRC checksum */
        uint8_t             reserved2[512 - 92]; /* must be 0 */
} __attribute__ ((packed));

struct gpt_record {
        uint8_t             boot_indicator; /* unused by EFI, set to 0x80 for bootable */
        uint8_t             start_head; /* unused by EFI, pt start in CHS */
        uint8_t             start_sector; /* unused by EFI, pt start in CHS */
        uint8_t             start_track;
        uint8_t             os_type; /* EFI and legacy non-EFI OS types */
        uint8_t             end_head; /* unused by EFI, pt end in CHS */
        uint8_t             end_sector; /* unused by EFI, pt end in CHS */
        uint8_t             end_track; /* unused by EFI, pt end in CHS */
        uint32_t            starting_lba; /* used by EFI - start addr of the on disk pt */
        uint32_t            size_in_lba; /* used by EFI - size of pt in LBA */
} __attribute__ ((packed));

/* Protected MBR and legacy MBR share same structure */
struct gpt_legacy_mbr {
        uint8_t             boot_code[440];
        uint32_t            unique_mbr_signature;
        uint16_t            unknown;
        struct gpt_record   partition_record[4];
        uint16_t            signature;
} __attribute__ ((packed));

/*
 * Here be dragons!
 * See: http://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
 */
#define DEF_GUID(_u, _n) \
        { \
                .typestr = (_u), \
                .name = (_n),    \
        }

static struct fdisk_parttype gpt_parttypes[] =
{
        /* Generic OS */
        DEF_GUID("C12A7328-F81F-11D2-BA4B-00A0C93EC93B", N_("EFI System")),

        DEF_GUID("024DEE41-33E7-11D3-9D69-0008C781F39F", N_("MBR partition scheme")),
        /* Hah!IdontneedEFI */
        DEF_GUID("21686148-6449-6E6F-744E-656564454649", N_("BIOS boot partition")),

        /* Windows */
        DEF_GUID("E3C9E316-0B5C-4DB8-817D-F92DF00215AE", N_("Microsoft reserved")),
        DEF_GUID("EBD0A0A2-B9E5-4433-87C0-68B6B72699C7", N_("Microsoft basic data")),
        DEF_GUID("5808C8AA-7E8F-42E0-85D2-E1E90434CFB3", N_("Microsoft LDM metadata")),
        DEF_GUID("AF9B60A0-1431-4F62-BC68-3311714A69AD", N_("Microsoft LDM data")),
        DEF_GUID("DE94BBA4-06D1-4D40-A16A-BFD50179D6AC", N_("Windows recovery evironment")),
        DEF_GUID("37AFFC90-EF7D-4E96-91C3-2D7AE055B174", N_("IBM General Parallel Fs")),

        /* HP-UX */
        DEF_GUID("75894C1E-3AEB-11D3-B7C1-7B03A0000000", N_("HP-UX data partition")),
        DEF_GUID("E2A1E728-32E3-11D6-A682-7B03A0000000", N_("HP-UX service partition")),

        /* Linux */
        DEF_GUID("0FC63DAF-8483-4772-8E79-3D69D8477DE4", N_("Linux filesystem")),
        DEF_GUID("A19D880F-05FC-4D3B-A006-743F0F84911E", N_("Linux RAID")),
        DEF_GUID("0657FD6D-A4AB-43C4-84E5-0933C84B4F4F", N_("Linux swap")),
        DEF_GUID("E6D6D379-F507-44C2-A23C-238F2A3DF928", N_("Linux LVM")),
        DEF_GUID("8DA63339-0007-60C0-C436-083AC8230908", N_("Linux reserved")),

        /* FreeBSD */
        DEF_GUID("516E7CB4-6ECF-11D6-8FF8-00022D09712B", N_("FreeBSD data")),
        DEF_GUID("83BD6B9D-7F41-11DC-BE0B-001560B84F0F", N_("FreeBSD boot")),
        DEF_GUID("516E7CB5-6ECF-11D6-8FF8-00022D09712B", N_("FreeBSD swap")),
        DEF_GUID("516E7CB6-6ECF-11D6-8FF8-00022D09712B", N_("FreeBSD UFS")),
        DEF_GUID("516E7CBA-6ECF-11D6-8FF8-00022D09712B", N_("FreeBSD ZFS")),
        DEF_GUID("516E7CB8-6ECF-11D6-8FF8-00022D09712B", N_("FreeBSD Vinum")),

        /* Apple OSX */
        DEF_GUID("48465300-0000-11AA-AA11-00306543ECAC", N_("Apple HFS/HFS+")),
        DEF_GUID("55465300-0000-11AA-AA11-00306543ECAC", N_("Apple UFS")),
        DEF_GUID("52414944-0000-11AA-AA11-00306543ECAC", N_("Apple RAID")),
        DEF_GUID("52414944-5F4F-11AA-AA11-00306543ECAC", N_("Apple RAID offline")),
        DEF_GUID("426F6F74-0000-11AA-AA11-00306543ECAC", N_("Apple boot")),
        DEF_GUID("4C616265-6C00-11AA-AA11-00306543ECAC", N_("Apple label")),
        DEF_GUID("5265636F-7665-11AA-AA11-00306543ECAC", N_("Apple TV recovery")),
        DEF_GUID("53746F72-6167-11AA-AA11-00306543ECAC", N_("Apple Core storage")),

        /* Solaris */
        DEF_GUID("6A82CB45-1DD2-11B2-99A6-080020736631", N_("Solaris boot")),
        DEF_GUID("6A85CF4D-1DD2-11B2-99A6-080020736631", N_("Solaris root")),
        /* same as Apple ZFS */
        DEF_GUID("6A898CC3-1DD2-11B2-99A6-080020736631", N_("Solaris /usr & Apple ZFS")),
        DEF_GUID("6A87C46F-1DD2-11B2-99A6-080020736631", N_("Solaris swap")),
        DEF_GUID("6A8B642B-1DD2-11B2-99A6-080020736631", N_("Solaris backup")),
        DEF_GUID("6A8EF2E9-1DD2-11B2-99A6-080020736631", N_("Solaris /var")),
        DEF_GUID("6A90BA39-1DD2-11B2-99A6-080020736631", N_("Solaris /home")),
        DEF_GUID("6A9283A5-1DD2-11B2-99A6-080020736631", N_("Solaris alternate sector")),
        DEF_GUID("6A945A3B-1DD2-11B2-99A6-080020736631", N_("Solaris reserved 1")),
        DEF_GUID("6A9630D1-1DD2-11B2-99A6-080020736631", N_("Solaris reserved 2")),
        DEF_GUID("6A980767-1DD2-11B2-99A6-080020736631", N_("Solaris reserved 3")),
        DEF_GUID("6A96237F-1DD2-11B2-99A6-080020736631", N_("Solaris reserved 4")),
        DEF_GUID("6A8D2AC7-1DD2-11B2-99A6-080020736631", N_("Solaris reserved 5")),

        /* NetBSD */
        DEF_GUID("49F48D32-B10E-11DC-B99B-0019D1879648", N_("NetBSD swap")),
        DEF_GUID("49F48D5A-B10E-11DC-B99B-0019D1879648", N_("NetBSD FFS")),
        DEF_GUID("49F48D82-B10E-11DC-B99B-0019D1879648", N_("NetBSD LFS")),
        DEF_GUID("2DB519C4-B10E-11DC-B99B-0019D1879648", N_("NetBSD concatenated")),
        DEF_GUID("2DB519EC-B10E-11DC-B99B-0019D1879648", N_("NetBSD encrypted")),
        DEF_GUID("49F48DAA-B10E-11DC-B99B-0019D1879648", N_("NetBSD RAID")),

        /* ChromeOS */
        DEF_GUID("FE3A2A5D-4F32-41A7-B725-ACCC3285A309", N_("ChromeOS kernel")),
        DEF_GUID("3CB8E202-3B7E-47DD-8A3C-7FF2A13CFCEC", N_("ChromeOS root fs")),
        DEF_GUID("2E0A753D-9E48-43B0-8337-B15192CB1B5E", N_("ChromeOS reserved")),

        /* MidnightBSD */
        DEF_GUID("85D5E45A-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD data")),
        DEF_GUID("85D5E45E-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD boot")),
        DEF_GUID("85D5E45B-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD swap")),
        DEF_GUID("0394Ef8B-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD UFS")),
        DEF_GUID("85D5E45D-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD ZFS")),
        DEF_GUID("85D5E45C-237C-11E1-B4B3-E89A8F7FC3A7", N_("MidnightBSD Vinum")),
};

/* gpt_entry macros */
#define gpt_partition_start(_e)         le64_to_cpu((_e)->lba_start)
#define gpt_partition_end(_e)           le64_to_cpu((_e)->lba_end)

/*
 * in-memory fdisk GPT stuff
 */
struct fdisk_gpt_label {
        struct fdisk_label      head;           /* generic part */

        /* gpt specific part */
        struct gpt_header       *pheader;       /* primary header */
        struct gpt_header       *bheader;       /* backup header */
        struct gpt_entry        *ents;          /* entries (partitions) */
};

static void gpt_deinit(struct fdisk_label *lb);

static inline struct fdisk_gpt_label *self_label(struct fdisk_context *cxt)
{
        return (struct fdisk_gpt_label *) cxt->label;
}

/*
 * Returns the partition length, or 0 if end is before beginning.
 */
static uint64_t gpt_partition_size(const struct gpt_entry *e)
{
        uint64_t start = gpt_partition_start(e);
        uint64_t end = gpt_partition_end(e);

        return start > end ? 0 : end - start + 1ULL;
}

#ifdef CONFIG_LIBFDISK_DEBUG
/* prints UUID in the real byte order! */
static void dbgprint_uuid(const char *mesg, struct gpt_guid *guid)
{
        const unsigned char *uuid = (unsigned char *) guid;

        fprintf(stderr, "%s: "
                "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x\n",
                mesg,
                uuid[0], uuid[1], uuid[2], uuid[3],
                uuid[4], uuid[5],
                uuid[6], uuid[7],
                uuid[8], uuid[9],
                uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],uuid[15]);
}
#endif

/*
 * UUID is traditionally 16 byte big-endian array, except Intel EFI
 * specification where the UUID is a structure of little-endian fields.
 */
static void swap_efi_guid(struct gpt_guid *uid)
{
        uid->time_low = swab32(uid->time_low);
        uid->time_mid = swab16(uid->time_mid);
        uid->time_hi_and_version = swab16(uid->time_hi_and_version);
}

static int string_to_guid(const char *in, struct gpt_guid *guid)
{
        if (uuid_parse(in, (unsigned char *) guid))     /* BE */
                return -1;
        swap_efi_guid(guid);                            /* LE */
        return 0;
}

static char *guid_to_string(struct gpt_guid *guid, char *out)
{
        struct gpt_guid u = *guid;      /* LE */

        swap_efi_guid(&u);              /* BE */
        uuid_unparse_upper((unsigned char *) &u, out);

        return out;
}

static const char *gpt_get_header_revstr(struct gpt_header *header)
{
        if (!header)
                goto unknown;

        switch (header->revision) {
        case GPT_HEADER_REVISION_V1_02:
                return "1.2";
        case GPT_HEADER_REVISION_V1_00:
                return "1.0";
        case GPT_HEADER_REVISION_V0_99:
                return "0.99";
        default:
                goto unknown;
        }

unknown:
        return "unknown";
}

static inline int partition_unused(const struct gpt_entry *e)
{
        return !memcmp(&e->type, &GPT_UNUSED_ENTRY_GUID,
                        sizeof(struct gpt_guid));
}

/*
 * Builds a clean new valid protective MBR - will wipe out any existing data.
 * Returns 0 on success, otherwise < 0 on error.
 */
static int gpt_mknew_pmbr(struct fdisk_context *cxt)
{
        struct gpt_legacy_mbr *pmbr = NULL;

        if (!cxt || !cxt->firstsector)
                return -ENOSYS;

        fdisk_zeroize_firstsector(cxt);

        pmbr = (struct gpt_legacy_mbr *) cxt->firstsector;

        pmbr->signature = cpu_to_le16(MSDOS_MBR_SIGNATURE);
        pmbr->partition_record[0].os_type      = EFI_PMBR_OSTYPE;
        pmbr->partition_record[0].start_sector = 1;
        pmbr->partition_record[0].end_head     = 0xFE;
        pmbr->partition_record[0].end_sector   = 0xFF;
        pmbr->partition_record[0].end_track    = 0xFF;
        pmbr->partition_record[0].starting_lba = cpu_to_le32(1);
        pmbr->partition_record[0].size_in_lba  =
                cpu_to_le32(min((uint32_t) cxt->total_sectors - 1, 0xFFFFFFFF));

        return 0;
}

/* some universal differences between the headers */
static void gpt_mknew_header_common(struct fdisk_context *cxt,
                                    struct gpt_header *header, uint64_t lba)
{
        if (!cxt || !header)
                return;

        header->my_lba = cpu_to_le64(lba);

        if (lba == GPT_PRIMARY_PARTITION_TABLE_LBA) { /* primary */
                header->alternative_lba = cpu_to_le64(cxt->total_sectors - 1);
                header->partition_entry_lba = cpu_to_le64(2);
        } else { /* backup */
                uint64_t esz = le32_to_cpu(header->npartition_entries) * sizeof(struct gpt_entry);
                uint64_t esects = (esz + cxt->sector_size - 1) / cxt->sector_size;

                header->alternative_lba = cpu_to_le64(GPT_PRIMARY_PARTITION_TABLE_LBA);
                header->partition_entry_lba = cpu_to_le64(cxt->total_sectors - 1 - esects);
        }
}

/*
 * Builds a new GPT header (at sector lba) from a backup header2.
 * If building a primary header, then backup is the secondary, and vice versa.
 *
 * Always pass a new (zeroized) header to build upon as we don't
 * explicitly zero-set some values such as CRCs and reserved.
 *
 * Returns 0 on success, otherwise < 0 on error.
 */
static int gpt_mknew_header_from_bkp(struct fdisk_context *cxt,
                                     struct gpt_header *header,
                                     uint64_t lba,
                                     struct gpt_header *header2)
{
        if (!cxt || !header || !header2)
                return -ENOSYS;

        header->signature              = header2->signature;
        header->revision               = header2->revision;
        header->size                   = header2->size;
        header->npartition_entries     = header2->npartition_entries;
        header->sizeof_partition_entry = header2->sizeof_partition_entry;
        header->first_usable_lba       = header2->first_usable_lba;
        header->last_usable_lba        = header2->last_usable_lba;

        memcpy(&header->disk_guid,
               &header2->disk_guid, sizeof(header2->disk_guid));
        gpt_mknew_header_common(cxt, header, lba);

        return 0;
}

/*
 * Builds a clean new GPT header (currently under revision 1.0).
 *
 * Always pass a new (zeroized) header to build upon as we don't
 * explicitly zero-set some values such as CRCs and reserved.
 *
 * Returns 0 on success, otherwise < 0 on error.
 */
static int gpt_mknew_header(struct fdisk_context *cxt,
                            struct gpt_header *header, uint64_t lba)
{
        uint64_t esz = 0, first, last;

        if (!cxt || !header)
                return -ENOSYS;

        esz = sizeof(struct gpt_entry) * GPT_NPARTITIONS / cxt->sector_size;

        header->signature = cpu_to_le64(GPT_HEADER_SIGNATURE);
        header->revision  = cpu_to_le32(GPT_HEADER_REVISION_V1_00);
        header->size      = cpu_to_le32(sizeof(struct gpt_header));

        /*
         * 128 partitions is the default. It can go behond this, however,
         * we're creating a de facto header here, so no funny business.
         */
        header->npartition_entries     = cpu_to_le32(GPT_NPARTITIONS);
        header->sizeof_partition_entry = cpu_to_le32(sizeof(struct gpt_entry));

        last = cxt->total_sectors - 2 - esz;
        first = esz + 2;

        if (first < cxt->first_lba && cxt->first_lba < last)
                /* Align according to topology */
                first = cxt->first_lba;

        header->first_usable_lba = cpu_to_le64(first);
        header->last_usable_lba  = cpu_to_le64(last);

        gpt_mknew_header_common(cxt, header, lba);
        uuid_generate_random((unsigned char *) &header->disk_guid);
        swap_efi_guid(&header->disk_guid);

        return 0;
}

/*
 * Checks if there is a valid protective MBR partition table.
 * Returns 0 if it is invalid or failure. Otherwise, return
 * GPT_MBR_PROTECTIVE or GPT_MBR_HYBRID, depeding on the detection.
 */
static int valid_pmbr(struct fdisk_context *cxt)
{
        int i, ret = 0; /* invalid by default */
        struct gpt_legacy_mbr *pmbr = NULL;

        if (!cxt->firstsector)
                goto done;

        pmbr = (struct gpt_legacy_mbr *) cxt->firstsector;

        if (le16_to_cpu(pmbr->signature) != MSDOS_MBR_SIGNATURE)
                goto done;

        /* LBA of the GPT partition header */
        if (pmbr->partition_record[0].starting_lba !=
            cpu_to_le32(GPT_PRIMARY_PARTITION_TABLE_LBA))
                goto done;

        /* seems like a valid MBR was found, check DOS primary partitions */
        for (i = 0; i < 4; i++) {
                if (pmbr->partition_record[i].os_type == EFI_PMBR_OSTYPE) {
                        /*
                         * Ok, we at least know that there's a protective MBR,
                         * now check if there are other partition types for
                         * hybrid MBR.
                         */
                        ret = GPT_MBR_PROTECTIVE;
                        goto check_hybrid;
                }
        }
check_hybrid:
        if (ret != GPT_MBR_PROTECTIVE)
                goto done;
        for (i = 0 ; i < 4; i++) {
                if ((pmbr->partition_record[i].os_type != EFI_PMBR_OSTYPE) &&
                    (pmbr->partition_record[i].os_type != 0x00))
                        ret = GPT_MBR_HYBRID;
        }

        /*
         * Protective MBRs take up the lesser of the whole disk
         * or 2 TiB (32bit LBA), ignoring the rest of the disk.
         *
         * Hybrid MBRs do not necessarily comply with this.
         */
        if (ret == GPT_MBR_PROTECTIVE) {
                if (le32_to_cpu(pmbr->partition_record[0].size_in_lba) !=
                    min((uint32_t) cxt->total_sectors - 1, 0xFFFFFFFF))
                        ret = 0;
        }
done:
        return ret;
}

static uint64_t last_lba(struct fdisk_context *cxt)
{
        struct stat s;

        memset(&s, 0, sizeof(s));
        if (fstat(cxt->dev_fd, &s) == -1) {
                fdisk_warn(cxt, _("gpt: stat() failed"));
                return 0;
        }

        if (S_ISBLK(s.st_mode))
                return cxt->total_sectors - 1;
        else if (S_ISREG(s.st_mode)) {
                uint64_t sectors = s.st_size >> cxt->sector_size;
                return (sectors / cxt->sector_size) - 1ULL;
        } else
                fdisk_warnx(cxt, _("gpt: cannot handle files with mode %o"), s.st_mode);
        return 0;
}

static ssize_t read_lba(struct fdisk_context *cxt, uint64_t lba,
                        void *buffer, const size_t bytes)
{
        off_t offset = lba * cxt->sector_size;

        if (lseek(cxt->dev_fd, offset, SEEK_SET) == (off_t) -1)
                return -1;
        return read(cxt->dev_fd, buffer, bytes) != bytes;
}


/* Returns the GPT entry array */
static struct gpt_entry *gpt_read_entries(struct fdisk_context *cxt,
                                         struct gpt_header *header)
{
        ssize_t sz;
        struct gpt_entry *ret = NULL;
        off_t offset;

        assert(cxt);
        assert(header);

        sz = le32_to_cpu(header->npartition_entries) *
             le32_to_cpu(header->sizeof_partition_entry);

        ret = calloc(1, sz);
        if (!ret)
                return NULL;
        offset = le64_to_cpu(header->partition_entry_lba) *
                       cxt->sector_size;

        if (offset != lseek(cxt->dev_fd, offset, SEEK_SET))
                goto fail;
        if (sz != read(cxt->dev_fd, ret, sz))
                goto fail;

        return ret;

fail:
        free(ret);
        return NULL;
}

static inline uint32_t count_crc32(const unsigned char *buf, size_t len)
{
        return (crc32(~0L, buf, len) ^ ~0L);
}

/*
 * Recompute header and partition array 32bit CRC checksums.
 * This function does not fail - if there's corruption, then it
 * will be reported when checksuming it again (ie: probing or verify).
 */
static void gpt_recompute_crc(struct gpt_header *header, struct gpt_entry *ents)
{
        uint32_t crc = 0;
        size_t entry_sz = 0;

        if (!header)
                return;

        /* header CRC */
        header->crc32 = 0;
        crc = count_crc32((unsigned char *) header, le32_to_cpu(header->size));
        header->crc32 = cpu_to_le32(crc);

        /* partition entry array CRC */
        header->partition_entry_array_crc32 = 0;
        entry_sz = le32_to_cpu(header->npartition_entries) *
                le32_to_cpu(header->sizeof_partition_entry);

        crc = count_crc32((unsigned char *) ents, entry_sz);
        header->partition_entry_array_crc32 = cpu_to_le32(crc);
}

/*
 * Compute the 32bit CRC checksum of the partition table header.
 * Returns 1 if it is valid, otherwise 0.
 */
static int gpt_check_header_crc(struct gpt_header *header, struct gpt_entry *ents)
{
        uint32_t crc, orgcrc = le32_to_cpu(header->crc32);

        header->crc32 = 0;
        crc = count_crc32((unsigned char *) header, le32_to_cpu(header->size));
        header->crc32 = cpu_to_le32(orgcrc);

        if (crc == le32_to_cpu(header->crc32))
                return 1;

        /*
         * If we have checksum mismatch it may be due to stale data,
         * like a partition being added or deleted. Recompute the CRC again
         * and make sure this is not the case.
         */
        if (ents) {
                gpt_recompute_crc(header, ents);
                orgcrc = le32_to_cpu(header->crc32);
                header->crc32 = 0;
                crc = count_crc32((unsigned char *) header, le32_to_cpu(header->size));
                header->crc32 = cpu_to_le32(orgcrc);

                return crc == le32_to_cpu(header->crc32);
        }

        return 0;
}

/*
 * It initializes the partition entry array.
 * Returns 1 if the checksum is valid, otherwise 0.
 */
static int gpt_check_entryarr_crc(struct gpt_header *header,
                                  struct gpt_entry *ents)
{
        int ret = 0;
        ssize_t entry_sz;
        uint32_t crc;

        if (!header || !ents)
                goto done;

        entry_sz = le32_to_cpu(header->npartition_entries) *
                   le32_to_cpu(header->sizeof_partition_entry);

        if (!entry_sz)
                goto done;

        crc = count_crc32((unsigned char *) ents, entry_sz);
        ret = (crc == le32_to_cpu(header->partition_entry_array_crc32));
done:
        return ret;
}

static int gpt_check_lba_sanity(struct fdisk_context *cxt, struct gpt_header *header)
{
        int ret = 0;
        uint64_t lu, fu, lastlba = last_lba(cxt);

        fu = le64_to_cpu(header->first_usable_lba);
        lu = le64_to_cpu(header->last_usable_lba);

        /* check if first and last usable LBA make sense */
        if (lu < fu) {
                DBG(LABEL, dbgprint("error: header last LBA is before first LBA"));
                goto done;
        }

        /* check if first and last usable LBAs with the disk's last LBA */
        if (fu > lastlba || lu > lastlba) {
                DBG(LABEL, dbgprint("error: header LBAs are after the disk's last LBA"));
                goto done;
        }

        /* the header has to be outside usable range */
        if (fu < GPT_PRIMARY_PARTITION_TABLE_LBA &&
            GPT_PRIMARY_PARTITION_TABLE_LBA < lu) {
                DBG(LABEL, dbgprint("error: header outside of usable range"));
                goto done;
        }

        ret = 1; /* sane */
done:
        return ret;
}

/* Check if there is a valid header signature */
static int gpt_check_signature(struct gpt_header *header)
{
        return header->signature == cpu_to_le64(GPT_HEADER_SIGNATURE);
}

/*
 * Return the specified GPT Header, or NULL upon failure/invalid.
 * Note that all tests must pass to ensure a valid header,
 * we do not rely on only testing the signature for a valid probe.
 */
static struct gpt_header *gpt_read_header(struct fdisk_context *cxt,
                                          uint64_t lba,
                                          struct gpt_entry **_ents)
{
        struct gpt_header *header = NULL;
        struct gpt_entry *ents = NULL;
        uint32_t hsz;

        if (!cxt)
                return NULL;

        header = calloc(1, sizeof(*header));
        if (!header)
                return NULL;

        /* read and verify header */
        if (read_lba(cxt, lba, header, sizeof(struct gpt_header)) != 0)
                goto invalid;

        if (!gpt_check_signature(header))
                goto invalid;

        if (!gpt_check_header_crc(header, NULL))
                goto invalid;

        /* read and verify entries */
        ents = gpt_read_entries(cxt, header);
        if (!ents)
                goto invalid;

        if (!gpt_check_entryarr_crc(header, ents))
                goto invalid;

        if (!gpt_check_lba_sanity(cxt, header))
                goto invalid;

        /* valid header must be at MyLBA */
        if (le64_to_cpu(header->my_lba) != lba)
                goto invalid;

        /* make sure header size is between 92 and sector size bytes */
        hsz = le32_to_cpu(header->size);
        if (hsz < GPT_HEADER_MINSZ || hsz > cxt->sector_size)
                goto invalid;

        if (_ents)
                *_ents = ents;
        else
                free(ents);

        return header;
invalid:
        free(header);
        free(ents);
        return NULL;
}

/*
 * Returns the number of partitions that are in use.
 */
static unsigned partitions_in_use(struct gpt_header *header, struct gpt_entry *e)
{
        uint32_t i, used = 0;

        if (!header || ! e)
                return 0;

        for (i = 0; i < le32_to_cpu(header->npartition_entries); i++)
                if (!partition_unused(&e[i]))
                        used++;
        return used;
}


/*
 * Check if a partition is too big for the disk (sectors).
 * Returns the faulting partition number, otherwise 0.
 */
static uint32_t partition_check_too_big(struct gpt_header *header,
                                   struct gpt_entry *e, uint64_t sectors)
{
        uint32_t i;

        for (i = 0; i < le32_to_cpu(header->npartition_entries); i++) {
                if (partition_unused(&e[i]))
                        continue;
                if (gpt_partition_end(&e[i]) >= sectors)
                        return i + 1;
        }

        return 0;
}

/*
 * Check if a partition ends before it begins
 * Returns the faulting partition number, otherwise 0.
 */
static uint32_t partition_start_after_end(struct gpt_header *header, struct gpt_entry *e)
{
        uint32_t i;

        for (i = 0; i < le32_to_cpu(header->npartition_entries); i++) {
                if (partition_unused(&e[i]))
                        continue;
                if (gpt_partition_start(&e[i]) > gpt_partition_end(&e[i]))
                        return i + 1;
        }

        return 0;
}

/*
 * Check if partition e1 overlaps with partition e2
 */
static inline int partition_overlap(struct gpt_entry *e1, struct gpt_entry *e2)
{
        uint64_t start1 = gpt_partition_start(e1);
        uint64_t end1   = gpt_partition_end(e1);
        uint64_t start2 = gpt_partition_start(e2);
        uint64_t end2   = gpt_partition_end(e2);

        return (start1 && start2 && (start1 <= end2) != (end1 < start2));
}

/*
 * Find any paritions that overlap.
 */
static uint32_t partition_check_overlaps(struct gpt_header *header, struct gpt_entry *e)
{
        uint32_t i, j;

        for (i = 0; i < le32_to_cpu(header->npartition_entries); i++)
                for (j = 0; j < i; j++) {
                        if (partition_unused(&e[i]) ||
                            partition_unused(&e[j]))
                                continue;
                        if (partition_overlap(&e[i], &e[j])) {
                                DBG(LABEL, dbgprint("GPT partitions overlap detected [%u vs. %u]", i, j));
                                return i + 1;
                        }
                }

        return 0;
}

/*
 * Find the first available block after the starting point; returns 0 if
 * there are no available blocks left, or error. From gdisk.
 */
static uint64_t find_first_available(struct gpt_header *header,
                                     struct gpt_entry *e, uint64_t start)
{
        uint64_t first;
        uint32_t i, first_moved = 0;

        uint64_t fu, lu;

        if (!header || !e)
                return 0;

        fu = le64_to_cpu(header->first_usable_lba);
        lu = le64_to_cpu(header->last_usable_lba);

        /*
         * Begin from the specified starting point or from the first usable
         * LBA, whichever is greater...
         */
        first = start < fu ? fu : start;

        /*
         * Now search through all partitions; if first is within an
         * existing partition, move it to the next sector after that
         * partition and repeat. If first was moved, set firstMoved
         * flag; repeat until firstMoved is not set, so as to catch
         * cases where partitions are out of sequential order....
         */
        do {
                first_moved = 0;
                for (i = 0; i < le32_to_cpu(header->npartition_entries); i++) {
                        if (partition_unused(&e[i]))
                                continue;
                        if (first < gpt_partition_start(&e[i]))
                                continue;
                        if (first <= gpt_partition_end(&e[i])) {
                                first = gpt_partition_end(&e[i]) + 1;
                                first_moved = 1;
                        }
                }
        } while (first_moved == 1);

        if (first > lu)
                first = 0;

        return first;
}


/* Returns last available sector in the free space pointed to by start. From gdisk. */
static uint64_t find_last_free(struct gpt_header *header,
                               struct gpt_entry *e, uint64_t start)
{
        uint32_t i;
        uint64_t nearest_start;

        if (!header || !e)
                return 0;

        nearest_start = le64_to_cpu(header->last_usable_lba);

        for (i = 0; i < le32_to_cpu(header->npartition_entries); i++) {
                uint64_t ps = gpt_partition_start(&e[i]);

                if (nearest_start > ps && ps > start)
                        nearest_start = ps - 1;
        }

        return nearest_start;
}

/* Returns the last free sector on the disk. From gdisk. */
static uint64_t find_last_free_sector(struct gpt_header *header,
                                      struct gpt_entry *e)
{
        uint32_t i, last_moved;
        uint64_t last = 0;

        if (!header || !e)
                goto done;

        /* start by assuming the last usable LBA is available */
        last = le64_to_cpu(header->last_usable_lba);
        do {
                last_moved = 0;
                for (i = 0; i < le32_to_cpu(header->npartition_entries); i++) {
                        if ((last >= gpt_partition_start(&e[i])) &&
                            (last <= gpt_partition_end(&e[i]))) {
                                last = gpt_partition_start(&e[i]) - 1;
                                last_moved = 1;
                        }
                }
        } while (last_moved == 1);
done:
        return last;
}

/*
 * Finds the first available sector in the largest block of unallocated
 * space on the disk. Returns 0 if there are no available blocks left.
 * From gdisk.
 */
static uint64_t find_first_in_largest(struct gpt_header *header, struct gpt_entry *e)
{
        uint64_t start = 0, first_sect, last_sect;
        uint64_t segment_size, selected_size = 0, selected_segment = 0;

        if (!header || !e)
                goto done;

        do {
                first_sect =  find_first_available(header, e, start);
                if (first_sect != 0) {
                        last_sect = find_last_free(header, e, first_sect);
                        segment_size = last_sect - first_sect + 1;

                        if (segment_size > selected_size) {
                                selected_size = segment_size;
                                selected_segment = first_sect;
                        }
                        start = last_sect + 1;
                }
        } while (first_sect != 0);

done:
        return selected_segment;
}

/*
 * Find the total number of free sectors, the number of segments in which
 * they reside, and the size of the largest of those segments. From gdisk.
 */
static uint64_t get_free_sectors(struct fdisk_context *cxt, struct gpt_header *header,
                                 struct gpt_entry *e, uint32_t *nsegments,
                                 uint64_t *largest_segment)
{
        uint32_t num = 0;
        uint64_t first_sect, last_sect;
        uint64_t largest_seg = 0, segment_sz;
        uint64_t totfound = 0, start = 0; /* starting point for each search */

        if (!cxt->total_sectors)
                goto done;

        do {
                first_sect = find_first_available(header, e, start);
                if (first_sect) {
                        last_sect = find_last_free(header, e, first_sect);
                        segment_sz = last_sect - first_sect + 1;

                        if (segment_sz > largest_seg)
                                largest_seg = segment_sz;
                        totfound += segment_sz;
                        num++;
                        start = last_sect + 1;
                }
        } while (first_sect);

done:
        if (nsegments)
                *nsegments = num;
        if (largest_segment)
                *largest_segment = largest_seg;

        return totfound;
}

static int gpt_probe_label(struct fdisk_context *cxt)
{
        int mbr_type;
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        mbr_type = valid_pmbr(cxt);
        if (!mbr_type)
                goto failed;

        DBG(LABEL, dbgprint("found a %s MBR", mbr_type == GPT_MBR_PROTECTIVE ?
                            "protective" : "hybrid"));

        /* primary header */
        gpt->pheader = gpt_read_header(cxt, GPT_PRIMARY_PARTITION_TABLE_LBA,
                                       &gpt->ents);

        /*
         * TODO: If the primary GPT is corrupt, we must check the last LBA of the
         * device to see if it has a valid GPT Header and point to a valid GPT
         * Partition Entry Array.
         * If it points to a valid GPT Partition Entry Array, then software should
         * restore the primary GPT if allowed by platform policy settings.
         *
         * For now we just abort GPT probing!
         */
        if (!gpt->pheader || !gpt->ents)
                goto failed;

        /* OK, probing passed, now initialize backup header and fdisk variables. */
        gpt->bheader = gpt_read_header(cxt, last_lba(cxt), NULL);

        cxt->label->nparts_max = le32_to_cpu(gpt->pheader->npartition_entries);
        cxt->label->nparts_cur = partitions_in_use(gpt->pheader, gpt->ents);

        fdisk_warnx(cxt, _("WARNING: fdisk GPT support is currently new, and therefore "
                 "in an experimental phase. Use at your own discretion."));

        return 1;
failed:
        DBG(LABEL, dbgprint("GPT probe failed"));
        gpt_deinit(cxt->label);
        return 0;
}

/*
 * Stolen from libblkid - can be removed once partition semantics
 * are added to the fdisk API.
 */
static char *encode_to_utf8(unsigned char *src, size_t count)
{
        uint16_t c;
        char *dest;
        size_t i, j, len = count;

        dest = calloc(1, count);
        if (!dest)
                return NULL;

        for (j = i = 0; i + 2 <= count; i += 2) {
                /* always little endian */
                c = (src[i+1] << 8) | src[i];
                if (c == 0) {
                        dest[j] = '\0';
                        break;
                } else if (c < 0x80) {
                        if (j+1 >= len)
                                break;
                        dest[j++] = (uint8_t) c;
                } else if (c < 0x800) {
                        if (j+2 >= len)
                                break;
                        dest[j++] = (uint8_t) (0xc0 | (c >> 6));
                        dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
                } else {
                        if (j+3 >= len)
                                break;
                        dest[j++] = (uint8_t) (0xe0 | (c >> 12));
                        dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
                        dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
                }
        }
        dest[j] = '\0';

        return dest;
}

/*
 * List label partitions.
 * This function must currently exist to comply with standard fdisk
 * requirements, but once partition semantics are added to the fdisk
 * API it can be removed for custom implementation (see gpt_label struct).
 */
static int gpt_list_disklabel(struct fdisk_context *cxt)
{
        int rc, trunc = TT_FL_TRUNC;
        uint32_t i;
        struct fdisk_gpt_label *gpt;
        struct gpt_header *h;
        uint64_t fu;
        uint64_t lu;
        struct tt *tb = NULL;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);
        h = gpt->pheader;
        fu = le64_to_cpu(gpt->pheader->first_usable_lba);
        lu = le64_to_cpu(gpt->pheader->last_usable_lba);

        tb = tt_new_table(TT_FL_FREEDATA);
        if (!tb)
                return -ENOMEM;

        /* don't trunc anything in expert mode */
        if (fdisk_context_display_details(cxt)) {
                trunc = 0;
                fdisk_info(cxt, _("First LBA: %ju"), h->first_usable_lba);
                fdisk_info(cxt, _("Last LBA: %ju"), h->last_usable_lba);
                fdisk_info(cxt, _("Alternative LBA: %ju"), h->alternative_lba);
                fdisk_info(cxt, _("Partitions entries LBA: %ju"), h->partition_entry_lba);
                fdisk_info(cxt, _("Allocated partition entries: %ju"), h->npartition_entries);
        }
        tt_define_column(tb, _("Device"), 0.1, 0);
        tt_define_column(tb, _("Start"),   12, TT_FL_RIGHT);
        tt_define_column(tb, _("End"),     12, TT_FL_RIGHT);
        tt_define_column(tb, _("Size"),     6, TT_FL_RIGHT);
        tt_define_column(tb, _("Type"),   0.1, trunc);

        if (fdisk_context_display_details(cxt)) {
                tt_define_column(tb, _("UUID"),  36, 0);
                tt_define_column(tb, _("Name"), 0.2, trunc);
        }

        for (i = 0; i < le32_to_cpu(h->npartition_entries); i++) {
                struct gpt_entry *e = &gpt->ents[i];
                char *sizestr = NULL, *p;
                uint64_t start = gpt_partition_start(e);
                uint64_t size = gpt_partition_size(e);
                struct fdisk_parttype *t;
                struct tt_line *ln;
                char u_str[37];

                if (partition_unused(&gpt->ents[i]) || start == 0)
                        continue;
                /* the partition has to inside usable range */
                if (start < fu || start + size - 1 > lu)
                        continue;
                ln = tt_add_line(tb, NULL);
                if (!ln)
                        continue;

                if (fdisk_context_display_details(cxt) &&
                    asprintf(&p, "%ju", size * cxt->sector_size) > 0)
                        sizestr = p;
                else
                        sizestr = size_to_human_string(SIZE_SUFFIX_1LETTER,
                                               size * cxt->sector_size);
                t = fdisk_get_partition_type(cxt, i);

                /* basic columns */
                p = fdisk_partname(cxt->dev_path, i + 1);
                if (p)
                        tt_line_set_data(ln, 0, p);
                if (asprintf(&p, "%ju", start) > 0)
                        tt_line_set_data(ln, 1, p);
                if (asprintf(&p, "%ju", gpt_partition_end(e)) > 0)
                        tt_line_set_data(ln, 2, p);
                if (sizestr)
                        tt_line_set_data(ln, 3, sizestr);
                if (t && t->name)
                        tt_line_set_data(ln, 4, strdup(t->name));

                /* expert menu column(s) */
                if (fdisk_context_display_details(cxt)) {
                        char *name = encode_to_utf8(
                                        (unsigned char *)e->name,
                                        sizeof(e->name));

                        if (guid_to_string(&e->partition_guid, u_str))
                                tt_line_set_data(ln, 5, strdup(u_str));
                        if (name)
                                tt_line_set_data(ln, 6, name);
                }

                fdisk_warn_alignment(cxt, start, i);
                fdisk_free_parttype(t);
        }

        rc = fdisk_print_table(cxt, tb);
        tt_free_table(tb);

        return rc;
}

/*
 * Write partitions.
 * Returns 0 on success, or corresponding error otherwise.
 */
static int gpt_write_partitions(struct fdisk_context *cxt,
                                struct gpt_header *header, struct gpt_entry *ents)
{
        off_t offset = le64_to_cpu(header->partition_entry_lba) * cxt->sector_size;
        uint32_t nparts = le32_to_cpu(header->npartition_entries);
        uint32_t totwrite = nparts * le32_to_cpu(header->sizeof_partition_entry);
        ssize_t rc;

        if (offset != lseek(cxt->dev_fd, offset, SEEK_SET))
                goto fail;

        rc = write(cxt->dev_fd, ents, totwrite);
        if (rc > 0 && totwrite == (uint32_t) rc)
                return 0;
fail:
        return -errno;
}

/*
 * Write a GPT header to a specified LBA
 * Returns 0 on success, or corresponding error otherwise.
 */
static int gpt_write_header(struct fdisk_context *cxt,
                            struct gpt_header *header, uint64_t lba)
{
        off_t offset = lba * cxt->sector_size;

        if (offset != lseek(cxt->dev_fd, offset, SEEK_SET))
                goto fail;
        if (cxt->sector_size ==
            (size_t) write(cxt->dev_fd, header, cxt->sector_size))
                return 0;
fail:
        return -errno;
}

/*
 * Write the protective MBR.
 * Returns 0 on success, or corresponding error otherwise.
 */
static int gpt_write_pmbr(struct fdisk_context *cxt)
{
        off_t offset;
        struct gpt_legacy_mbr *pmbr = NULL;

        assert(cxt);
        assert(cxt->firstsector);

        pmbr = (struct gpt_legacy_mbr *) cxt->firstsector;

        /* zero out the legacy partitions */
        memset(pmbr->partition_record, 0, sizeof(pmbr->partition_record));

        pmbr->signature = cpu_to_le16(MSDOS_MBR_SIGNATURE);
        pmbr->partition_record[0].os_type      = EFI_PMBR_OSTYPE;
        pmbr->partition_record[0].start_sector = 1;
        pmbr->partition_record[0].end_head     = 0xFE;
        pmbr->partition_record[0].end_sector   = 0xFF;
        pmbr->partition_record[0].end_track    = 0xFF;
        pmbr->partition_record[0].starting_lba = cpu_to_le32(1);

        /*
         * Set size_in_lba to the size of the disk minus one. If the size of the disk
         * is too large to be represented by a 32bit LBA (2Tb), set it to 0xFFFFFFFF.
         */
        if (cxt->total_sectors - 1 > 0xFFFFFFFFULL)
                pmbr->partition_record[0].size_in_lba = cpu_to_le32(0xFFFFFFFF);
        else
                pmbr->partition_record[0].size_in_lba =
                        cpu_to_le32(cxt->total_sectors - 1UL);

        offset = GPT_PMBR_LBA * cxt->sector_size;
        if (offset != lseek(cxt->dev_fd, offset, SEEK_SET))
                goto fail;

        /* pMBR covers the first sector (LBA) of the disk */
        if (write_all(cxt->dev_fd, pmbr, cxt->sector_size))
                goto fail;
        return 0;
fail:
        return -errno;
}

/*
 * Writes in-memory GPT and pMBR data to disk.
 * Returns 0 if successful write, otherwise, a corresponding error.
 * Any indication of error will abort the operation.
 */
static int gpt_write_disklabel(struct fdisk_context *cxt)
{
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        /* we do not want to mess up hybrid MBRs by creating a valid pmbr */
        if (valid_pmbr(cxt) == GPT_MBR_HYBRID)
                goto err0;

        /* check that disk is big enough to handle the backup header */
        if (le64_to_cpu(gpt->pheader->alternative_lba) > cxt->total_sectors)
                goto err0;

        /* check that the backup header is properly placed */
        if (le64_to_cpu(gpt->pheader->alternative_lba) < cxt->total_sectors - 1)
                /* TODO: correct this (with user authorization) and write */
                goto err0;

        if (partition_check_overlaps(gpt->pheader, gpt->ents))
                goto err0;

        /* recompute CRCs for both headers */
        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        /*
         * UEFI requires writing in this specific order:
         *   1) backup partition tables
         *   2) backup GPT header
         *   3) primary partition tables
         *   4) primary GPT header
         *   5) protective MBR
         *
         * If any write fails, we abort the rest.
         */
        if (gpt_write_partitions(cxt, gpt->bheader, gpt->ents) != 0)
                goto err1;
        if (gpt_write_header(cxt, gpt->bheader,
                             le64_to_cpu(gpt->pheader->alternative_lba)) != 0)
                goto err1;
        if (gpt_write_partitions(cxt, gpt->pheader, gpt->ents) != 0)
                goto err1;
        if (gpt_write_header(cxt, gpt->pheader, GPT_PRIMARY_PARTITION_TABLE_LBA) != 0)
                goto err1;
        if (gpt_write_pmbr(cxt) != 0)
                goto err1;

        DBG(LABEL, dbgprint("GPT write success"));
        return 0;
err0:
        DBG(LABEL, dbgprint("GPT write failed: incorrect input"));
        errno = EINVAL;
        return -EINVAL;
err1:
        DBG(LABEL, dbgprint("GPT write failed: %m"));
        return -errno;
}

/*
 * Verify data integrity and report any found problems for:
 *   - primary and backup header validations
 *   - paritition validations
 */
static int gpt_verify_disklabel(struct fdisk_context *cxt)
{
        int nerror = 0;
        unsigned int ptnum;
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if (!gpt || !gpt->bheader) {
                nerror++;
                fdisk_warnx(cxt, _("Disk does not contain a valid backup header."));
        }

        if (!gpt_check_header_crc(gpt->pheader, gpt->ents)) {
                nerror++;
                fdisk_warnx(cxt, _("Invalid primary header CRC checksum."));
        }
        if (gpt->bheader && !gpt_check_header_crc(gpt->bheader, gpt->ents)) {
                nerror++;
                fdisk_warnx(cxt, _("Invalid backup header CRC checksum."));
        }

        if (!gpt_check_entryarr_crc(gpt->pheader, gpt->ents)) {
                nerror++;
                fdisk_warnx(cxt, _("Invalid partition entry checksum."));
        }

        if (!gpt_check_lba_sanity(cxt, gpt->pheader)) {
                nerror++;
                fdisk_warnx(cxt, _("Invalid primary header LBA sanity checks."));
        }
        if (gpt->bheader && !gpt_check_lba_sanity(cxt, gpt->bheader)) {
                nerror++;
                fdisk_warnx(cxt, _("Invalid backup header LBA sanity checks."));
        }

        if (le64_to_cpu(gpt->pheader->my_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA) {
                nerror++;
                fdisk_warnx(cxt, _("MyLBA mismatch with real position at primary header."));
        }
        if (gpt->bheader && le64_to_cpu(gpt->bheader->my_lba) != last_lba(cxt)) {
                nerror++;
                fdisk_warnx(cxt, _("MyLBA mismatch with real position at backup header."));

        }
        if (le64_to_cpu(gpt->pheader->alternative_lba) >= cxt->total_sectors) {
                nerror++;
                fdisk_warnx(cxt, _("Disk is to small to hold all data."));
        }

        /*
         * if the GPT is the primary table, check the alternateLBA
         * to see if it is a valid GPT
         */
        if (gpt->bheader && (le64_to_cpu(gpt->pheader->my_lba) !=
                             le64_to_cpu(gpt->bheader->alternative_lba))) {
                nerror++;
                fdisk_warnx(cxt, _("Primary and backup header mismatch."));
        }

        ptnum = partition_check_overlaps(gpt->pheader, gpt->ents);
        if (ptnum) {
                nerror++;
                fdisk_warnx(cxt, _("Partition %u overlaps with partition %u."),
                                ptnum, ptnum+1);
        }

        ptnum = partition_check_too_big(gpt->pheader, gpt->ents, cxt->total_sectors);
        if (ptnum) {
                nerror++;
                fdisk_warnx(cxt, _("Partition %u is too big for the disk."),
                                ptnum);
        }

        ptnum = partition_start_after_end(gpt->pheader, gpt->ents);
        if (ptnum) {
                nerror++;
                fdisk_warnx(cxt, _("Partition %u ends before it starts."),
                                ptnum);
        }

        if (!nerror) { /* yay :-) */
                uint32_t nsegments = 0;
                uint64_t free_sectors = 0, largest_segment = 0;

                fdisk_info(cxt, _("No errors detected"));
                fdisk_info(cxt, _("Header version: %s"), gpt_get_header_revstr(gpt->pheader));
                fdisk_info(cxt, _("Using %u out of %d partitions."),
                       partitions_in_use(gpt->pheader, gpt->ents),
                       le32_to_cpu(gpt->pheader->npartition_entries));

                free_sectors = get_free_sectors(cxt, gpt->pheader, gpt->ents,
                                                &nsegments, &largest_segment);
                fdisk_info(cxt, _("A total of %ld free sectors available in %d segment(s) "
                         "(largest %ld)."),
                       free_sectors, nsegments, largest_segment);
        } else
                fdisk_warnx(cxt, _("Detected %d error(s)."), nerror);

        return 0;
}

/* Delete a single GPT partition, specified by partnum. */
static int gpt_delete_partition(struct fdisk_context *cxt,
                                size_t partnum)
{
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if (partnum >= cxt->label->nparts_max
            ||  partition_unused(&gpt->ents[partnum]))
                return -EINVAL;

        /* hasta la vista, baby! */
        memset(&gpt->ents[partnum], 0, sizeof(struct gpt_entry));
        if (!partition_unused(&gpt->ents[partnum]))
                return -EINVAL;
        else {
                gpt_recompute_crc(gpt->pheader, gpt->ents);
                gpt_recompute_crc(gpt->bheader, gpt->ents);
                cxt->label->nparts_cur--;
                fdisk_label_set_changed(cxt->label, 1);
        }

        return 0;
}

static void gpt_entry_set_type(struct gpt_entry *e, struct gpt_guid *uuid)
{
        e->type = *uuid;
        DBG(LABEL, dbgprint_uuid("new type", &(e->type)));
}

/*
 * Create a new GPT partition entry, specified by partnum, and with a range
 * of fsect to lsenct sectors, of type t.
 * Returns 0 on success, or negative upon failure.
 */
static int gpt_create_new_partition(struct fdisk_context *cxt,
                                    size_t partnum, uint64_t fsect, uint64_t lsect,
                                    struct gpt_guid *type,
                                    struct gpt_entry *entries)
{
        struct gpt_entry *e = NULL;
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if (fsect > lsect || partnum >= cxt->label->nparts_max)
                return -EINVAL;

        e = calloc(1, sizeof(*e));
        if (!e)
                return -ENOMEM;
        e->lba_end = cpu_to_le64(lsect);
        e->lba_start = cpu_to_le64(fsect);

        gpt_entry_set_type(e, type);

        /*
         * Any time a new partition entry is created a new GUID must be
         * generated for that partition, and every partition is guaranteed
         * to have a unique GUID.
         */
        uuid_generate_random((unsigned char *) &e->partition_guid);
        swap_efi_guid(&e->partition_guid);

        memcpy(&entries[partnum], e, sizeof(*e));

        gpt_recompute_crc(gpt->pheader, entries);
        gpt_recompute_crc(gpt->bheader, entries);

        free(e);
        return 0;
}

/* Performs logical checks to add a new partition entry */
static int gpt_add_partition(
                struct fdisk_context *cxt,
                size_t partnum,
                struct fdisk_parttype *t)
{
        uint64_t user_f, user_l;        /* user input ranges for first and last sectors */
        uint64_t disk_f, disk_l;        /* first and last available sector ranges on device*/
        uint64_t dflt_f, dflt_l;        /* largest segment (default) */
        struct gpt_guid typeid;
        struct fdisk_gpt_label *gpt;
        struct gpt_header *pheader;
        struct gpt_entry *ents;
        struct fdisk_ask *ask = NULL;
        int rc;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if (partnum >= cxt->label->nparts_max)
                return -EINVAL;

        pheader = gpt->pheader;
        ents = gpt->ents;

        if (!partition_unused(&ents[partnum])) {
                fdisk_warnx(cxt, _("Partition %zd is already defined. "
                         "Delete it before re-adding it."), partnum +1);
                return -EINVAL;
        }
        if (le32_to_cpu(pheader->npartition_entries) ==
                        partitions_in_use(pheader, ents)) {
                fdisk_warnx(cxt, _("All partitions are already in use."));
                return -EINVAL;
        }

        if (!get_free_sectors(cxt, pheader, ents, NULL, NULL)) {
                fdisk_warnx(cxt, _("No free sectors available."));
                return -ENOSPC;
        }

        disk_f = find_first_available(pheader, ents, 0);
        disk_l = find_last_free_sector(pheader, ents);

        /* the default is the largest free space */
        dflt_f = find_first_in_largest(pheader, ents);
        dflt_l = find_last_free(pheader, ents, dflt_f);

        /* align the default in range <dflt_f,dflt_l>*/
        dflt_f = fdisk_align_lba_in_range(cxt, dflt_f, dflt_f, dflt_l);

        string_to_guid(t && t->typestr ? t->typestr : GPT_DEFAULT_ENTRY_TYPE, &typeid);

        /* get user input for first and last sectors of the new partition */
        for (;;) {
                if (!ask)
                        ask = fdisk_new_ask();
                else
                        fdisk_reset_ask(ask);

                /* First sector */
                fdisk_ask_set_query(ask, _("First sector"));
                fdisk_ask_set_type(ask, FDISK_ASKTYPE_NUMBER);
                fdisk_ask_number_set_low(ask,     disk_f);      /* minimal */
                fdisk_ask_number_set_default(ask, dflt_f);      /* default */
                fdisk_ask_number_set_high(ask,    disk_l);      /* maximal */

                rc = fdisk_do_ask(cxt, ask);
                if (rc)
                        goto done;

                user_f = fdisk_ask_number_get_result(ask);
                if (user_f != find_first_available(pheader, ents, user_f)) {
                        fdisk_warnx(cxt, _("Sector %ju already used."), user_f);
                        continue;
                }

                fdisk_reset_ask(ask);

                /* Last sector */
                dflt_l = find_last_free(pheader, ents, user_f);

                fdisk_ask_set_query(ask, _("Last sector, +sectors or +size{K,M,G,T,P}"));
                fdisk_ask_set_type(ask, FDISK_ASKTYPE_OFFSET);
                fdisk_ask_number_set_low(ask,     user_f);      /* minimal */
                fdisk_ask_number_set_default(ask, dflt_l);      /* default */
                fdisk_ask_number_set_high(ask,    dflt_l);      /* maximal */
                fdisk_ask_number_set_base(ask,    user_f);      /* base for relative input */
                fdisk_ask_number_set_unit(ask,    cxt->sector_size);

                rc = fdisk_do_ask(cxt, ask);
                if (rc)
                        goto done;

                user_l = fdisk_ask_number_get_result(ask);
                if (fdisk_ask_number_is_relative(ask))
                        user_l = fdisk_align_lba_in_range(cxt, user_l, user_f, dflt_l) - 1;
                if (user_l > user_f && user_l <= disk_l)
                        break;
        }

        if (gpt_create_new_partition(cxt, partnum,
                                     user_f, user_l, &typeid, ents) != 0)
                fdisk_warnx(cxt, _("Could not create partition %zd"), partnum + 1);
        else {
                fdisk_info(cxt, _("Created partition %zd\n"), partnum + 1);
                cxt->label->nparts_cur++;
                fdisk_label_set_changed(cxt->label, 1);
        }

        rc = 0;
done:
        fdisk_free_ask(ask);
        return rc;
}

/*
 * Create a new GPT disklabel - destroys any previous data.
 */
static int gpt_create_disklabel(struct fdisk_context *cxt)
{
        int rc = 0;
        ssize_t esz = 0;
        char str[37];
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        /* label private stuff has to be empty, see gpt_deinit() */
        assert(gpt->pheader == NULL);
        assert(gpt->bheader == NULL);

        /*
         * When no header, entries or pmbr is set, we're probably
         * dealing with a new, empty disk - so always allocate memory
         * to deal with the data structures whatever the case is.
         */
        rc = gpt_mknew_pmbr(cxt);
        if (rc < 0)
                goto done;

        /* primary */
        gpt->pheader = calloc(1, sizeof(*gpt->pheader));
        if (!gpt->pheader) {
                rc = -ENOMEM;
                goto done;
        }
        rc = gpt_mknew_header(cxt, gpt->pheader, GPT_PRIMARY_PARTITION_TABLE_LBA);
        if (rc < 0)
                goto done;

        /* backup ("copy" primary) */
        gpt->bheader = calloc(1, sizeof(*gpt->bheader));
        if (!gpt->bheader) {
                rc = -ENOMEM;
                goto done;
        }
        rc = gpt_mknew_header_from_bkp(cxt, gpt->bheader,
                        last_lba(cxt), gpt->pheader);
        if (rc < 0)
                goto done;

        esz = le32_to_cpu(gpt->pheader->npartition_entries) *
              le32_to_cpu(gpt->pheader->sizeof_partition_entry);
        gpt->ents = calloc(1, esz);
        if (!gpt->ents) {
                rc = -ENOMEM;
                goto done;
        }
        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        cxt->label->nparts_max = le32_to_cpu(gpt->pheader->npartition_entries);
        cxt->label->nparts_cur = 0;

        guid_to_string(&gpt->pheader->disk_guid, str);
        fdisk_info(cxt, _("Building a new GPT disklabel (GUID: %s)"), str);
        fdisk_label_set_changed(cxt->label, 1);
done:
        return rc;
}

static int gpt_get_disklabel_id(struct fdisk_context *cxt, char **id)
{
        struct fdisk_gpt_label *gpt;
        char str[37];

        assert(cxt);
        assert(id);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);
        guid_to_string(&gpt->pheader->disk_guid, str);

        *id = strdup(str);
        if (!*id)
                return -ENOMEM;
        return 0;
}

static int gpt_set_disklabel_id(struct fdisk_context *cxt)
{
        struct fdisk_gpt_label *gpt;
        struct gpt_guid uuid;
        char *str, *old, *new;
        int rc;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);
        if (fdisk_ask_string(cxt,
                        _("Enter new disk UUID (in 8-4-4-4-12 format)"), &str))
                return -EINVAL;

        rc = string_to_guid(str, &uuid);
        free(str);

        if (rc) {
                fdisk_warnx(cxt, _("Failed to parse your UUID."));
                return rc;
        }

        gpt_get_disklabel_id(cxt, &old);

        gpt->pheader->disk_guid = uuid;
        gpt->bheader->disk_guid = uuid;

        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        gpt_get_disklabel_id(cxt, &new);

        fdisk_info(cxt, _("Changing disk identifier from %s to %s."), old, new);

        free(old);
        free(new);
        fdisk_label_set_changed(cxt->label, 1);
        return 0;
}


static struct fdisk_parttype *gpt_get_partition_type(
                struct fdisk_context *cxt,
                size_t i)
{
        struct fdisk_parttype *t;
        char str[37];
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if ((uint32_t) i >= le32_to_cpu(gpt->pheader->npartition_entries))
                return NULL;

        guid_to_string(&gpt->ents[i].type, str);
        t = fdisk_get_parttype_from_string(cxt, str);
        if (!t)
                t = fdisk_new_unknown_parttype(0, str);

        return t;
}


static int gpt_set_partition_type(
                struct fdisk_context *cxt,
                size_t i,
                struct fdisk_parttype *t)
{
        struct gpt_guid uuid;
        struct fdisk_gpt_label *gpt;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);
        if ((uint32_t) i >= le32_to_cpu(gpt->pheader->npartition_entries)
             || !t || !t->typestr || string_to_guid(t->typestr, &uuid) != 0)
                return -EINVAL;

        gpt_entry_set_type(&gpt->ents[i], &uuid);
        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        fdisk_label_set_changed(cxt->label, 1);
        return 0;
}

static int gpt_get_partition_status(
                struct fdisk_context *cxt,
                size_t i,
                int *status)
{
        struct fdisk_gpt_label *gpt;
        struct gpt_entry *e;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        gpt = self_label(cxt);

        if (!status || (uint32_t) i >= le32_to_cpu(gpt->pheader->npartition_entries))
                return -EINVAL;

        e = &gpt->ents[i];
        *status = FDISK_PARTSTAT_NONE;

        if (!partition_unused(e) || gpt_partition_start(e))
                *status = FDISK_PARTSTAT_USED;

        return 0;
}

int fdisk_gpt_partition_set_uuid(struct fdisk_context *cxt, size_t i)
{
        struct fdisk_gpt_label *gpt;
        struct gpt_entry *e;
        struct gpt_guid uuid;
        char *str, new_u[37], old_u[37];
        int rc;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        DBG(LABEL, dbgprint("UUID change requested partno=%zd", i));

        gpt = self_label(cxt);

        if ((uint32_t) i >= le32_to_cpu(gpt->pheader->npartition_entries))
                return -EINVAL;

        if (fdisk_ask_string(cxt,
                        _("New UUID (in 8-4-4-4-12 format)"), &str))
                return -EINVAL;

        rc = string_to_guid(str, &uuid);
        free(str);

        if (rc) {
                fdisk_warnx(cxt, _("Failed to parse your UUID."));
                return rc;
        }

        e = &gpt->ents[i];

        guid_to_string(&e->partition_guid, old_u);
        guid_to_string(&uuid, new_u);
        fdisk_info(cxt, _("Changing partition UUID from %s to %s"),
                        old_u, new_u);

        e->partition_guid = uuid;
        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        fdisk_label_set_changed(cxt->label, 1);
        return 0;
}

int fdisk_gpt_partition_set_name(struct fdisk_context *cxt, size_t i)
{
        struct fdisk_gpt_label *gpt;
        struct gpt_entry *e;
        char *str, *old, name[GPT_PART_NAME_LEN] = { 0 };
        size_t sz;

        assert(cxt);
        assert(cxt->label);
        assert(fdisk_is_disklabel(cxt, GPT));

        DBG(LABEL, dbgprint("NAME change requested partno=%zd", i));

        gpt = self_label(cxt);

        if ((uint32_t) i >= le32_to_cpu(gpt->pheader->npartition_entries))
                return -EINVAL;

        if (fdisk_ask_string(cxt, _("New name"), &str))
                return -EINVAL;

        e = &gpt->ents[i];
        old = encode_to_utf8((unsigned char *)e->name, sizeof(e->name));

        fdisk_info(cxt, _("Changing partition name from '%s' to '%.*s'"),
                                old, GPT_PART_NAME_LEN, str);
        sz = strlen(str);
        if (sz) {
                if (sz > GPT_PART_NAME_LEN)
                        sz = GPT_PART_NAME_LEN;
                memcpy(name, str, sz);
        }
        free(str);
        free(old);

        for (i = 0; i < GPT_PART_NAME_LEN; i++)
                e->name[i] = cpu_to_le16((uint16_t) name[i]);

        gpt_recompute_crc(gpt->pheader, gpt->ents);
        gpt_recompute_crc(gpt->bheader, gpt->ents);

        fdisk_label_set_changed(cxt->label, 1);
        return 0;
}


/*
 * Deinitialize fdisk-specific variables
 */
static void gpt_deinit(struct fdisk_label *lb)
{
        struct fdisk_gpt_label *gpt = (struct fdisk_gpt_label *) lb;

        if (!gpt)
                return;

        free(gpt->ents);
        free(gpt->pheader);
        free(gpt->bheader);

        gpt->ents = NULL;
        gpt->pheader = NULL;
        gpt->bheader = NULL;
}

static const struct fdisk_label_operations gpt_operations =
{
        .probe          = gpt_probe_label,
        .write          = gpt_write_disklabel,
        .verify         = gpt_verify_disklabel,
        .create         = gpt_create_disklabel,
        .list           = gpt_list_disklabel,
        .get_id         = gpt_get_disklabel_id,
        .set_id         = gpt_set_disklabel_id,

        .part_add       = gpt_add_partition,
        .part_delete    = gpt_delete_partition,
        .part_get_type  = gpt_get_partition_type,
        .part_set_type  = gpt_set_partition_type,

        .part_get_status = gpt_get_partition_status,

        .deinit         = gpt_deinit
};

/*
 * allocates GPT in-memory stuff
 */
struct fdisk_label *fdisk_new_gpt_label(struct fdisk_context *cxt)
{
        struct fdisk_label *lb;
        struct fdisk_gpt_label *gpt;

        assert(cxt);

        gpt = calloc(1, sizeof(*gpt));
        if (!gpt)
                return NULL;

        /* initialize generic part of the driver */
        lb = (struct fdisk_label *) gpt;
        lb->name = "gpt";
        lb->id = FDISK_DISKLABEL_GPT;
        lb->op = &gpt_operations;
        lb->parttypes = gpt_parttypes;
        lb->nparttypes = ARRAY_SIZE(gpt_parttypes);

        return lb;
}