/*
 * Copyright (c) 2008 Vreixo Formoso
 * Copyright (c) 2010 - 2024 Thomas Schmitt
 *
 * This file is part of the libisofs project; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2 
 * or later as published by the Free Software Foundation. 
 * See COPYING file for details.
 */

#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif

#include "libisofs.h"
#include "system_area.h"
#include "eltorito.h"
#include "filesrc.h"
#include "ecma119_tree.h"
#include "image.h"
#include "messages.h"
#include "ecma119.h"
#include "writer.h"

#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

/* for gettimeofday() */
#include <sys/time.h>

/* >>> Need ./configure test for uuid_generate() which checks for:
       uuid_t, uuid_generate, the need for -luuid
*/
/*
#define Libisofs_with_uuid_generatE 1
*/
#ifdef Libisofs_with_uuid_generatE
#include <uuid/uuid.h>
#endif

/* O_BINARY is needed for Cygwin but undefined elsewhere */
#ifndef O_BINARY
#define O_BINARY 0
#endif


/*
 * Create a MBR for an isohybrid enabled ISOLINUX boot image.
 * See libisofs/make_isohybrid_mbr.c
 * Deprecated.
 */
int make_isohybrid_mbr(int bin_lba, int *img_blocks, char *mbr, int flag);

/*
 * The New ISOLINUX MBR Producer.
 * Be cautious with changing parameters. Only few combinations are tested.
 *
 */
int make_isolinux_mbr(uint32_t *img_blocks, Ecma119Image *t,
                      int part_offset, int part_number, int fs_type,
                      uint8_t *buf, int flag);

/* Find out whether GPT and APM are desired by isohybrid
   flag bit0 = register APM and GPT requests in Ecma119Image
*/
int assess_isohybrid_gpt_apm(Ecma119Image *t, int *gpt_count, int gpt_idx[128],
                             int *apm_count, int flag);


static int precompute_gpt(Ecma119Image *t);


/*
 * @param flag bit0= img_blocks is start address rather than end address:
                     do not subtract 1
               bit1= img_blocks is counted in 512-byte units rather than 2 KiB
 */
static
void iso_compute_cyl_head_sec(uint64_t img_blocks, int hpc, int sph,
                              uint32_t *end_lba, uint32_t *end_sec,
                              uint32_t *end_head, uint32_t *end_cyl, int flag)
{
    uint64_t secs;

    if(flag & 2)
        secs = img_blocks;
    else
        secs = img_blocks * 4;
    if (secs > (uint64_t) 0xfffffffc)
      secs = 0xfffffffc;                   /* truncate rather than roll over */
    if (flag & 1)
        *end_lba = secs;                              /* first valid 512-lba */
    else
        secs = *end_lba = secs - 1;                    /* last valid 512-lba */
    *end_cyl = secs / (sph * hpc);
    secs -= *end_cyl * sph * hpc;
    *end_head = secs / sph;
    *end_sec = secs - *end_head * sph + 1;   /* Sector count starts by 1 */
    if (*end_cyl >= 1024) {
        *end_cyl = 1023;
        *end_head = hpc - 1;
        *end_sec = sph;
    }
}

/* @param flag bit0= The path contains instructions for the interval reader
   @return ISO_SUCCESS     = ok, partition will be written
           ISO_SUCCESS + 1 = interval which shall be kept in place
           else : error code
*/
static int compute_partition_size(Ecma119Image *t, char *disk_path,
                                  uint32_t *size, int flag)
{
    int ret, keep;
    off_t num;
    struct stat stbuf;
    struct iso_interval_reader *ivr;
    off_t byte_count;

    if (flag & 1) {
        ret = iso_interval_reader_new(t->image, disk_path,
                                      &ivr, &byte_count, 0);
        if (ret < 0)
            return ret;
        *size = (byte_count + BLOCK_SIZE - 1) / BLOCK_SIZE;
        keep = iso_interval_reader_keep(t, ivr, 0);
        iso_interval_reader_destroy(&ivr, 0);
        if (keep < 0)
            return keep;
        return ISO_SUCCESS + (keep > 0);
    }

    *size = 0;
    ret = stat(disk_path, &stbuf);
    if (ret == -1)
        return ISO_BAD_PARTITION_FILE;
    if (! S_ISREG(stbuf.st_mode))
        return ISO_BAD_PARTITION_FILE;
    num = ((stbuf.st_size + 2047) / 2048);
    if (num > 0x3fffffff || num == 0)
        return ISO_BAD_PARTITION_FILE;
    *size = num;
    return ISO_SUCCESS;
}

/* Compute size and position of appended partitions.
   @param flag bit0= Partitions inside ISO : update t->curblock
*/
int iso_compute_append_partitions(Ecma119Image *t, int flag)
{
    int ret, i, sa_type, cyl_align, cyl_size = 0;
    int first_partition, last_partition;
    uint32_t pos, size, add_pos = 0;
    off_t start_byte, byte_count;
    char msg[128];

    sa_type = (t->system_area_options >> 2) & 0x3f;
    cyl_align = (t->system_area_options >> 8) & 0x3;
    if (sa_type == 0 && cyl_align == 3) {
        cyl_size = t->partition_heads_per_cyl * t->partition_secs_per_head;
        if (cyl_size % 4)
            cyl_size = 0;
        else
            cyl_size /= 4;
    }

#ifdef Libisofs_appended_partitions_inlinE

    pos = t->curblock;

#else

    pos = (t->vol_space_size + t->opts->ms_block);

#endif

    iso_tell_max_part_range(t->opts, &first_partition, &last_partition, 0);
    for (i = 0; i < ISO_MAX_PARTITIONS; i++) {
        if (t->opts->appended_partitions[i] == NULL)
    continue;
        if (t->opts->appended_partitions[i][0] == 0)
    continue;
        if (i + 1 > last_partition || i + 1 < first_partition) {
            sprintf(msg,
         "Partition number %d of appended partition is out of range [%d - %d]",
                    i + 1, first_partition, last_partition);
            iso_msgs_submit(0, msg, 0, "FAILURE", 0);
            return ISO_BAD_PARTITION_NO;
        }

        ret = compute_partition_size(t, t->opts->appended_partitions[i], &size,
                                     t->opts->appended_part_flags[i]);
        if (ret < 0)
            return ret;
        if (ret == ISO_SUCCESS + 1) {
            /* Interval from imported_iso in add-on session */
            t->appended_part_prepad[i] = 0;
            ret = iso_interval_reader_start_size(t,
                                               t->opts->appended_partitions[i],
                                               &start_byte, &byte_count, 0);
            if (ret < 0)
                return ret;
            t->appended_part_start[i] = start_byte / 2048;
            t->appended_part_size[i] = size;
            t->opts->iso_mbr_part_type = 0;
    continue;
        }

        add_pos = 0;
        if (sa_type == 3 && (pos % ISO_SUN_CYL_SIZE)) {
            add_pos = ISO_SUN_CYL_SIZE - (pos % ISO_SUN_CYL_SIZE);
        } else if (cyl_size > 0 && (pos % cyl_size)) {
            add_pos = cyl_size - (pos % cyl_size);
        }
        t->appended_part_prepad[i] = add_pos;
        t->appended_part_start[i] = pos + add_pos;

        if (cyl_size > 0 && (size % cyl_size)) {
            /* Obey cylinder alignment (missing data will be written as
               zeros by iso_write_partition_file()) */
            size += cyl_size - (size % cyl_size);
        }
        t->appended_part_size[i] = size;
        pos += add_pos + size;
        t->total_size += (((off_t) add_pos) + size) * 2048;
        if (flag & 1)
            t->curblock = pos;
    }
    return ISO_SUCCESS;
}


static int mbr_part_slot_is_unused(uint8_t *slot)
{
    int i;

    for (i = 0; i < 16; i++)
        if (slot[i] != 0)
    break;
    if (i >= 16)
        return 1;
    return 0;
}


/* @param flag
                bit1= partition_offset and partition_size are counted in
                      blocks of 512 rather than 2048
 */
static int write_mbr_partition_entry(int partition_number, int partition_type,
                  uint64_t partition_offset, uint64_t partition_size,
                  int sph, int hpc, uint8_t *buf, int flag)
{
    uint8_t *wpt;
    uint32_t end_lba, end_sec, end_head, end_cyl;
    uint32_t start_lba, start_sec, start_head, start_cyl;
    uint32_t after_end;
    int i;

    after_end = partition_offset + partition_size;
    iso_compute_cyl_head_sec((uint64_t) partition_offset, hpc, sph,
                             &start_lba, &start_sec, &start_head, &start_cyl,
                             1 | (flag & 2));
    iso_compute_cyl_head_sec((uint64_t) after_end, hpc, sph,
                             &end_lba, &end_sec, &end_head, &end_cyl,
                             (flag & 2));
    wpt = buf + 446 + (partition_number - 1) * 16;

    /* Not bootable */
    *(wpt++) = 0x00;

    /* C/H/S of the start */
    *(wpt++) = start_head;
    *(wpt++) = start_sec | ((start_cyl & 0x300) >> 2);
    *(wpt++) = start_cyl & 0xff;

    /* (partition type) */
    *(wpt++) = partition_type;

    /* 3 bytes of C/H/S end */
    *(wpt++) = end_head;
    *(wpt++) = end_sec | ((end_cyl & 0x300) >> 2);
    *(wpt++) = end_cyl & 0xff;
    
    /* LBA start in little endian */
    for (i = 0; i < 4; i++)
       *(wpt++) = (start_lba >> (8 * i)) & 0xff;

    /* Number of sectors in partition, little endian */
    end_lba = end_lba - start_lba + 1;
    for (i = 0; i < 4; i++)
       *(wpt++) = (end_lba >> (8 * i)) & 0xff;

    /* Afaik, partition tables are recognize donly with MBR signature */
    buf[510] = 0x55;
    buf[511] = 0xAA;

    return ISO_SUCCESS;
}


/* This is the gesture of grub-mkisofs --protective-msdos-label as explained by
   Vladimir Serbinenko <phcoder@gmail.com>, 2 April 2010, on grub-devel@gnu.org
   "Currently we use first and not last entry. You need to:
    1) Zero-fill 446-510
    2) Put 0x55, 0xAA into 510-512
    3) Put 0x80 (for bootable partition), 0, 2, 0 (C/H/S of the start), 0xcd
      (partition type), [3 bytes of C/H/S end], 0x01, 0x00, 0x00, 0x00 (LBA
      start in little endian), [LBA end in little endian] at 446-462
   "

   "C/H/S end" means the CHS address of the last block in the partition.
   It seems that not "[LBA end in little endian]" but "number of blocks"
   should go into bytes 458-461. But with a start lba of 1, this is the
   same number.
   See also http://en.wikipedia.org/wiki/Master_boot_record

   flag   bit0= do not write 0x55, 0xAA to 510,511
          bit1= do not mark partition as bootable
*/
static
int make_grub_msdos_label(uint32_t img_blocks, int sph, int hpc,
                          uint8_t part_type, uint8_t *buf, int flag)
{
    uint8_t *wpt;
    uint32_t end_lba, end_sec, end_head, end_cyl;
    int i;

    iso_compute_cyl_head_sec((uint64_t) img_blocks, hpc, sph,
                             &end_lba, &end_sec, &end_head, &end_cyl, 0);

    /* 1) Zero-fill 446-510 */
    wpt = buf + 446;
    memset(wpt, 0, 64);

    if (!(flag & 1)) {
        /* 2) Put 0x55, 0xAA into 510-512 (actually 510-511) */
        buf[510] = 0x55;
        buf[511] = 0xAA;
    }
    if ((!(flag & 2)) && part_type != 0xee && part_type != 0xef) {
      /* 3) Put 0x80 (for bootable partition), */
      *(wpt++) = 0x80;
    } else {
      *(wpt++) = 0;
    }

    /* 0, 2, 0 (C/H/S of the start), */
    *(wpt++) = 0;
    *(wpt++) = 2;
    *(wpt++) = 0;

    /* 0xcd (partition type) */
    *(wpt++) = part_type;

    /* [3 bytes of C/H/S end], */
    *(wpt++) = end_head;
    *(wpt++) = end_sec | ((end_cyl & 0x300) >> 2);
    *(wpt++) = end_cyl & 0xff;
    

    /* 0x01, 0x00, 0x00, 0x00 (LBA start in little endian), */
    *(wpt++) = 0x01;
    *(wpt++) = 0x00;
    *(wpt++) = 0x00;
    *(wpt++) = 0x00;

    /* [LBA end in little endian] */
    for (i = 0; i < 4; i++)
       *(wpt++) = (end_lba >> (8 * i)) & 0xff;

    /* at 446-462 */
    if (wpt - buf != 462) {
        fprintf(stderr,
        "libisofs: program error in make_grub_msdos_label: \"assert 462\"\n");
        return ISO_ASSERT_FAILURE;
    }
    return ISO_SUCCESS;
}


/* @param flag bit0= zeroize partitions entries 2, 3, 4
               bit1= UEFI protective MBR: start LBA = 1
*/
static
int iso_offset_partition_start(uint32_t img_blocks, int post_part_pad,
                               uint32_t partition_offset,
                               int sph, int hpc, uint8_t *buf, int flag)
{
    uint8_t *wpt;
    uint32_t end_lba, end_sec, end_head, end_cyl;
    uint32_t start_lba, start_sec, start_head, start_cyl;
    uint64_t img_hd_blocks;
    int i;

    iso_compute_cyl_head_sec((uint64_t) partition_offset, hpc, sph,
                           &start_lba, &start_sec, &start_head, &start_cyl, 1);
    img_hd_blocks = ((uint64_t) img_blocks) * 4 - post_part_pad / 512;
    iso_compute_cyl_head_sec(img_hd_blocks, hpc, sph,
                             &end_lba, &end_sec, &end_head, &end_cyl, 2);
    if (flag & 2) {
        start_lba = 1;
        start_sec = 2;
        start_head = start_cyl = 0;
    }
    wpt = buf + 446;

    /* Let pass only legal bootability values */
    if (*wpt != 0 && *wpt != 0x80)
        (*wpt) = 0;
    wpt++;

    /* C/H/S of the start */
    *(wpt++) = start_head;
    *(wpt++) = start_sec | ((start_cyl & 0x300) >> 2);
    *(wpt++) = start_cyl & 0xff;

    /* (partition type) */
    wpt++;

    /* 3 bytes of C/H/S end */
    *(wpt++) = end_head;
    *(wpt++) = end_sec | ((end_cyl & 0x300) >> 2);
    *(wpt++) = end_cyl & 0xff;
    
    /* LBA start in little endian */
    for (i = 0; i < 4; i++)
       *(wpt++) = (start_lba >> (8 * i)) & 0xff;

    /* Number of sectors in partition, little endian */
    end_lba = end_lba - start_lba + 1;
    for (i = 0; i < 4; i++)
       *(wpt++) = (end_lba >> (8 * i)) & 0xff;

    if (wpt - buf != 462) {
        fprintf(stderr,
    "libisofs: program error in iso_offset_partition_start: \"assert 462\"\n");
        return ISO_ASSERT_FAILURE;
    }

    if (flag & 1) /* zeroize the other partition entries */
        memset(wpt, 0, 3 * 16);

    return ISO_SUCCESS;
}


static int boot_nodes_from_iso_path(Ecma119Image *t, char *path, 
                                   IsoNode **iso_node, Ecma119Node **ecma_node,
                                   char *purpose, int flag)
{
    int ret;

    ret = iso_tree_path_to_node(t->image, path, iso_node);
    if (ret <= 0) {
        iso_msg_submit(t->image->id, ISO_BOOT_FILE_MISSING, 0,
                       "Cannot find in ISO image: %s '%s'", purpose, path);
        return ISO_BOOT_FILE_MISSING;
    }
    if ((*iso_node)->type != LIBISO_FILE) {
        iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
                       "Designated boot file is not a data file: '%s'", path);
        return ISO_BOOT_IMAGE_NOT_VALID;
    }

    *ecma_node= ecma119_search_iso_node(t, *iso_node);
    if (*ecma_node == NULL) {
        iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
                      "Program error: IsoFile has no Ecma119Node: '%s'", path);
        return ISO_ASSERT_FAILURE;
    } else {
        if ((*ecma_node)->type != ECMA119_FILE) {
            iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
              "Program error: Ecma119Node of IsoFile is no ECMA119_FILE: '%s'",
                          path);
            return ISO_ASSERT_FAILURE;
        }
    }
    return ISO_SUCCESS;
}


/* This function was implemented according to doc/boot_sectors.txt section
   "MIPS Volume Header" which was derived by Thomas Schmitt from
   cdrkit-1.1.10/genisoimage/boot-mips.c by Steve McIntyre which is based
   on work of Florian Lohoff and Thiemo Seufer who possibly learned from
   documents of MIPS Computer Systems, Inc. and Silicon Graphics Computer
   Systems, Inc.
   This function itself is entirely under copyright (C) 2010 Thomas Schmitt.
*/
static int make_mips_volume_header(Ecma119Image *t, uint8_t *buf, int flag)
{
    char *namept, *name_field;
    uint32_t num_cyl, idx, blocks, num, checksum;
    off_t image_size;
    static uint32_t bps = 512, spt = 32;
    Ecma119Node *ecma_node;
    IsoNode *node;
    IsoStream *stream;
    off_t file_size;
    uint32_t file_lba;
    int ret;

    /* Bytes 512 to 32767 may come from image or external file */
    memset(buf, 0, 512);

    image_size = t->curblock * 2048;

    /* 0 -   3 | 0x0be5a941 | Magic number */
    iso_msb(buf, 0x0be5a941, 4);

    /* 28 -  29 |  num_cyl_l | Number of usable cylinder, lower two bytes */
    num_cyl = (image_size + (bps * spt) - 1) / (bps * spt);
    iso_msb(buf + 28, num_cyl & 0xffff, 2);

    /* 32 -  33 |          1 | Number of tracks per cylinder */
    iso_msb(buf + 32, 1, 2);

    /* 35 -  35 |  num_cyl_h | Number of usable cylinders, high byte */
    buf[35] = (num_cyl >> 16) & 0xff;
    
    /* 38 -  39 |         32 | Sectors per track */
    iso_msb(buf + 38, spt, 2);

    /* 40 -  41 |        512 | Bytes per sector */
    iso_msb(buf + 40, bps, 2);

    /* 44 -  47 | 0x00000034 | Controller characteristics */
    iso_msb(buf + 44, 0x00000034, 4);

    /*  72 -  87 | ========== | Volume Directory Entry 1 */
    /*  72 -  79 |  boot_name | Boot file basename */
    /*  80 -  83 | boot_block | ISO 9660 LBA of boot file * 4 */
    /*  84 -  87 | boot_bytes | File length in bytes */
    /*  88 - 311 |          0 | Volume Directory Entries 2 to 15 */

    for (idx = 0; (int) idx < t->image->num_mips_boot_files; idx++) {
        ret = boot_nodes_from_iso_path(t, t->image->mips_boot_file_paths[idx], 
                                       &node, &ecma_node, "MIPS boot file", 0);
        if (ret < 0)
            return ret;

        namept = (char *) iso_node_get_name(node);
        name_field = (char *) (buf + (72 + 16 * idx));
        strncpy(name_field, namept, 8);

        file_lba = ecma_node->info.file->sections[0].block;

        iso_msb(buf + (72 + 16 * idx) + 8, file_lba * 4, 4);

        stream = iso_file_get_stream((IsoFile *) node);
        file_size = iso_stream_get_size(stream);

        /* genisoimage rounds up to full multiples of 2048.
           libisofs did this too until 2020, but the arcload mips boot loader
           throws error if the rounded size is stored here.
           So now the exact bytecount gets stored.
        */
        iso_msb(buf + (72 + 16 * idx) + 12, file_size, 4);
        
    }

    /* 408 - 411 |  part_blks | Number of 512 byte blocks in partition */
    blocks = (image_size + bps - 1) / bps;
    iso_msb(buf + 408, blocks, 4);
    /* 416 - 419 |          0 | Partition is volume header */
    iso_msb(buf + 416, 0, 4);

    /* 432 - 435 |  part_blks | Number of 512 byte blocks in partition */
    iso_msb(buf + 432, blocks, 4);
    iso_msb(buf + 444, 6, 4);

    /* 504 - 507 |   head_chk | Volume header checksum  
                                The two's complement of bytes 0 to 503 read
                                as big endian unsigned 32 bit:
                                  sum(32-bit-words) + head_chk == 0
    */
    checksum = 0;
    for (idx = 0; idx < 504; idx += 4) {
        num = iso_read_msb(buf + idx, 4);
        /* Addition modulo a natural number is commutative and associative.
           Thus the inverse of a sum is the sum of the inverses of the addends.
        */
        checksum -= num;
    }
    iso_msb(buf + 504, checksum, 4);

    return ISO_SUCCESS;
}


/* The following two functions were implemented according to
   doc/boot_sectors.txt section "MIPS Little Endian" which was derived
   by Thomas Schmitt from
   cdrkit-1.1.10/genisoimage/boot-mipsel.c by Steve McIntyre which is based
   on work of Florian Lohoff and Thiemo Seufer,
   and from <elf.h> by Free Software Foundation, Inc.

   Both functions are entirely under copyright (C) 2010 Thomas Schmitt.
*/

/**
 * Read the necessary ELF information from the first MIPS boot file.
 * This is done before image writing starts.
 */
int iso_read_mipsel_elf(Ecma119Image *t, int flag)
{
    uint32_t phdr_adr, todo, count;
    int ret;
    uint8_t *elf_buf = NULL;
    IsoNode *iso_node;
    Ecma119Node *ecma_node;
    IsoStream *stream;
    
    if (t->image->num_mips_boot_files <= 0)
        {ret = ISO_SUCCESS; goto ex;}

    LIBISO_ALLOC_MEM(elf_buf, uint8_t, 2048);
    ret = boot_nodes_from_iso_path(t, t->image->mips_boot_file_paths[0],
                                   &iso_node, &ecma_node, "MIPS boot file", 0);
    if (ret < 0)
        goto ex;
    stream = iso_file_get_stream((IsoFile *) iso_node);

    ret = iso_stream_open(stream);
    if (ret < 0) {
        iso_msg_submit(t->image->id, ret, 0,
                       "Cannot open designated MIPS boot file '%s'",
                       t->image->mips_boot_file_paths[0]);
        goto ex;
    }
    ret = iso_stream_read(stream, elf_buf, 32);
    if (ret != 32) {
cannot_read:;
        iso_stream_close(stream);
        iso_msg_submit(t->image->id, ret, 0,
                       "Cannot read from designated MIPS boot file '%s'",
                       t->image->mips_boot_file_paths[0]);
        goto ex;
    }


    /*  24 -  27 |    e_entry | Entry point virtual address */
    t->mipsel_e_entry = iso_read_lsb(elf_buf + 24, 4);

    /* 28 -  31 |    e_phoff | Program header table file offset */
    phdr_adr = iso_read_lsb(elf_buf + 28, 4);

    /* Skip stream up to byte address phdr_adr */
    todo = phdr_adr - 32;
    while (todo > 0) {
        if (todo > 2048)
            count = 2048;
        else
            count = todo;
        todo -= count;
        ret = iso_stream_read(stream, elf_buf, count);
        if (ret != (int) count)
            goto cannot_read;
    }
    ret = iso_stream_read(stream, elf_buf, 20);
    if (ret != 20)
        goto cannot_read;

    /*  4 -   7 |   p_offset | Segment file offset */
    t->mipsel_p_offset = iso_read_lsb(elf_buf + 4, 4);

    /*  8 -  11 |    p_vaddr | Segment virtual address */
    t->mipsel_p_vaddr = iso_read_lsb(elf_buf + 8, 4);

    /* 16 -  19 |   p_filesz | Segment size in file */
    t->mipsel_p_filesz = iso_read_lsb(elf_buf + 16, 4);

    iso_stream_close(stream);
    ret = ISO_SUCCESS;
ex:;
    LIBISO_FREE_MEM(elf_buf);
    return ret;
}


/**
 * Write DEC Bootblock from previously read ELF parameters.
 * This is done when image writing has already begun.
 */
static int make_mipsel_boot_block(Ecma119Image *t, uint8_t *buf, int flag)
{
    int ret;
    uint32_t seg_size, seg_start;
    IsoNode *iso_node;
    Ecma119Node *ecma_node;
    
    /* Bytes 512 to 32767 may come from image or external file */
    memset(buf, 0, 512);

    if (t->image->num_mips_boot_files <= 0)
        return ISO_SUCCESS;

    ret = boot_nodes_from_iso_path(t, t->image->mips_boot_file_paths[0],
                                   &iso_node, &ecma_node, "MIPS boot file", 0);
    if (ret < 0)
        return ret;

    /*  8 -  11 | 0x0002757a | Magic number */
    iso_lsb(buf + 8, 0x0002757a, 4);

    /* 12 -  15 |          1 | Mode  1: Multi extent boot */
    iso_lsb(buf + 12, 1, 4);

    /* 16 -  19 |   load_adr | Load address */
    iso_lsb(buf + 16, t->mipsel_p_vaddr, 4);

    /* 20 -  23 |   exec_adr | Execution address */
    iso_lsb(buf + 20, t->mipsel_e_entry, 4);

    /* 24 -  27 |   seg_size | Segment size in file. */
    seg_size = (t->mipsel_p_filesz + 511) / 512;
    iso_lsb(buf + 24, seg_size, 4);
    
    /* 28 -  31 |  seg_start | Segment file offset */
    seg_start = ecma_node->info.file->sections[0].block * 4
                + (t->mipsel_p_offset + 511) / 512;
    iso_lsb(buf + 28, seg_start, 4);
    
    return ISO_SUCCESS;
}


/* The following two functions were implemented according to
   doc/boot_sectors.txt section "SUN Disk Label and boot images" which
   was derived by Thomas Schmitt from
     cdrtools-2.01.01a77/mkisofs/sunlabel.h
     cdrtools-2.01.01a77/mkisofs/mkisofs.8
     by Joerg Schilling

   Both functions are entirely under copyright (C) 2010 Thomas Schmitt.
*/

/* @parm flag bit0= copy from next lower valid partition table entry
 */
static int write_sun_partition_entry(int partition_number,
                  char *appended_partitions[],
                  uint32_t partition_offset[], uint32_t partition_size[],
                  uint32_t cyl_size, uint8_t *buf, int flag)
{
    uint8_t *wpt;
    int read_idx, i;

    if (partition_number < 1 || partition_number > 8)
        return ISO_ASSERT_FAILURE;
    
    /* 142 - 173 | ========== | 8 partition entries of 4 bytes */
    wpt = buf + 142 + (partition_number - 1) * 4;
    if (partition_number == 1)
        iso_msb(wpt, 4, 2);                            /* 4 = User partition */
    else
        iso_msb(wpt, 2, 2);            /* 2 = Root partition with boot image */
    iso_msb(wpt + 2, 0x10, 2);              /* Permissions: 0x10 = read-only */

    /* 444 - 507 | ========== | Partition table */
    wpt = buf + 444 + (partition_number - 1) * 8;
    read_idx = partition_number - 1;
    if (flag & 1) {
        /* Search next lower valid partition table entry. #1 is default */
        for (read_idx = partition_number - 2; read_idx > 0; read_idx--)
            if (appended_partitions[read_idx] != NULL)
                if (appended_partitions[read_idx][0] != 0)
        break;
    }
    iso_msb(wpt, partition_offset[read_idx] / (uint32_t) ISO_SUN_CYL_SIZE, 4);
    iso_msb(wpt + 4, partition_size[read_idx] * 4, 4);

    /* 510 - 511 |   checksum | The result of exoring 2-byte words 0 to 254 */
    buf[510] = buf[511] = 0;
    for (i = 0; i < 510; i += 2) {
        buf[510] ^= buf[i];
        buf[511] ^= buf[i + 1];
    }

    return ISO_SUCCESS;
}

/**
 * Write SUN Disk Label with ISO in partition 1 and unused 2 to 8
 */
static int make_sun_disk_label(Ecma119Image *t, uint8_t *buf, int flag)
{
    int ret, i, l;
    uint64_t blk;

    /* Bytes 512 to 32767 may come from image or external file */
    memset(buf, 0, 512);

    /* 0 - 127 |      label | ASCII Label */
    if (t->opts->ascii_disc_label[0]) {
        for (l = 0; l < 128 && t->opts->ascii_disc_label[l] != 0; l++);
        if (l > 0)
            memcpy((char *) buf, t->opts->ascii_disc_label, l);
    } else {
        strcpy((char *) buf,
               "CD-ROM Disc with Sun sparc boot created by libisofs");
    }
    
    /* 128 - 131 |          1 | Layout version */
    iso_msb(buf + 128, 1, 4);

    /* 140 - 141 |          8 | Number of partitions */
    iso_msb(buf + 140, 8, 2);

    /* 188 - 191 | 0x600ddeee | vtoc sanity */
    iso_msb(buf + 188, 0x600ddeee, 4);

    /* 420 - 421 |        350 | Rotations per minute */
    iso_msb(buf + 420, 350, 2);

    /* 422 - 423 |       2048 | Number of physical cylinders (fixely 640 MB) */
    iso_msb(buf + 422, 2048, 2);

    /* 430 - 431 |          1 | interleave factor */
    iso_msb(buf + 430, 1, 2);

    /* 432 - 433 |       2048 | Number of data cylinders (fixely 640 MB) */
    iso_msb(buf + 432, 2048, 2);

    /* 436 - 437 |          1 | Number of heads per cylinder (1 cyl = 320 kB)*/
    iso_msb(buf + 436, 1, 2);

    /* 438 - 439 |        640 | Number of sectors per head (1 head = 320 kB) */
    iso_msb(buf + 438, 640, 2);

    /* 508 - 509 |     0xdabe | Magic Number */
    iso_msb(buf + 508, 0xdabe, 2);

    if (t->sparc_core_src != NULL) {
        /* May be used for grub-sparc. */
        blk= ((uint64_t) t->sparc_core_src->sections[0].block) *
             (uint64_t) 2048; 
        for (i = 0; i < 8; i++)
            buf[Libisofs_grub2_sparc_patch_adr_poS + i] = blk >> ((7 - i) * 8);
        iso_msb(buf + Libisofs_grub2_sparc_patch_size_poS,
                t->sparc_core_src->sections[0].size, 4);
    }

    /* Set partition 1 to describe ISO image and compute checksum */
    t->appended_part_start[0] = 0;
    t->appended_part_size[0] = t->curblock;
    ret = write_sun_partition_entry(1, t->opts->appended_partitions,
                  t->appended_part_start, t->appended_part_size,
                  ISO_SUN_CYL_SIZE, buf, 0);
    if (ret < 0)
        return ret;
    return ISO_SUCCESS;
}


static int hppa_palo_get_filepar(Ecma119Image *t, char *path,
                                 uint32_t *adr, uint32_t *len, int flag)
{
    int ret;
    IsoNode *iso_node;
    Ecma119Node *ecma_node;
    off_t adr64;

    ret = boot_nodes_from_iso_path(t, path,
                             &iso_node, &ecma_node, "HP-PA PALO boot file", 0);
    if (ret < 0)
        return ret;
    if (iso_node_get_type(iso_node) != LIBISO_FILE) {
        iso_msg_submit(t->image->id, ISO_HPPA_PALO_NOTREG, 0,
                       "HP-PA PALO file is not a data file");
        return ISO_HPPA_PALO_NOTREG;
    }
    adr64 = ((off_t) 2048) * (off_t) ecma_node->info.file->sections[0].block;
    if (adr64 > 0x7fffffff) {
        iso_msg_submit(t->image->id, ISO_HPPA_PALO_OFLOW, 0,
                       "HP-PA PALO boot address exceeds 2 GB");
        return ISO_HPPA_PALO_OFLOW;
    }
    *adr = adr64;
    *len = ecma_node->info.file->sections[0].size;
    return ISO_SUCCESS;
}


/**
 * Write HP-PA PALO boot sector. See doc/boot_sectors.txt
 *
 * learned from  cdrkit-1.1.10/genisoimage/boot-hppa.c
 * by Steve McIntyre <steve@einval.com>
 *    who states "Heavily inspired by palo"
 * Public mail conversations with Helge Deller, beginning with
 *    https://lists.debian.org/debian-hppa/2014/01/msg00016.html
 * http://git.kernel.org/cgit/linux/kernel/git/deller/palo.git/tree/lib/
 *    (especially struct firstblock in common.h and struct partition in part.h)
 *
 */
static int make_hppa_palo_sector(Ecma119Image *t, uint8_t *buf, int hdrversion,
                                 int flag)
{
    int ret;
    IsoImage *img;
    uint32_t adr, len;

    img = t->image;
    if (img->hppa_cmdline == NULL && img->hppa_bootloader == NULL &&
        img->hppa_kernel_32 == NULL && img->hppa_kernel_64 == NULL && 
        img->hppa_ramdisk == NULL)
        return ISO_SUCCESS;
    if (img->hppa_cmdline == NULL || img->hppa_bootloader == NULL ||
        img->hppa_kernel_32 == NULL || img->hppa_kernel_64 == NULL || 
        img->hppa_ramdisk == NULL) {
        iso_msg_submit(img->id, ISO_HPPA_PALO_INCOMPL, 0,
                       "Incomplete HP-PA PALO boot parameters");
        return ISO_HPPA_PALO_INCOMPL;
    }
    if (hdrversion == 4) {
        /* Bytes 256 to 32767 may come from loaded ISO image or external file */
        memset(buf, 0, 256);
    } else if(hdrversion == 5) {
        memset(buf, 0, 512);
        memset(buf + 1024, 0, 1024);
    } else {
        iso_msg_submit(img->id, ISO_WRONG_ARG_VALUE, 0,
                    "Unsupported HP-PA PALO header version %d (can do 4 or 5)",
                       hdrversion);
        return ISO_WRONG_ARG_VALUE;
    }

    /* Magic */
    iso_msb(buf + 0, 0x8000, 2);
    /* Name of boot loader */
    memcpy(buf + 2, "PALO", 5);
    /* Version */
    buf[7] = hdrversion;

    /* Byte address and byte count of the "HPPA 32-bit kernel" file
    */
    ret = hppa_palo_get_filepar(t, img->hppa_kernel_32, &adr, &len, 0);
    if (ret < 0)
        return ret;
    iso_msb(buf +  8, adr, 4);
    iso_msb(buf + 12, len, 4);

    /* Byte address and byte count of the "HPPA ramdisk" file
    */
    ret = hppa_palo_get_filepar(t, img->hppa_ramdisk, &adr, &len, 0);
    if (ret < 0)
        return ret;
    iso_msb(buf + 16, adr, 4);
    iso_msb(buf + 20, len, 4);

    if (hdrversion == 4) {
        /* "Command line" */
        if (strlen(img->hppa_cmdline) > 127) {
            iso_msg_submit(img->id, ISO_HPPA_PALO_CMDLEN, 0,
                           "HP-PA PALO command line too long");
            return ISO_HPPA_PALO_CMDLEN;
        }
        memcpy(buf + 24, img->hppa_cmdline, strlen(img->hppa_cmdline) + 1);
    }

    /* Byte address and byte count of the "HPPA 64-bit kernel" file
    */
    ret = hppa_palo_get_filepar(t, img->hppa_kernel_64, &adr, &len, 0);
    if (ret < 0)
        return ret;
    iso_msb(buf + 232, adr, 4);
    iso_msb(buf + 236, len, 4);

    /* Byte address and byte count of the "HPPA bootloader" file
    */
    ret = hppa_palo_get_filepar(t, img->hppa_bootloader, &adr, &len, 0);
    if (ret < 0)
        return ret;
    iso_msb(buf + 240, adr, 4);
    iso_msb(buf + 244, len, 4);

    if (hdrversion == 5) {
        if (strlen(img->hppa_cmdline) > 1023) {
            iso_msg_submit(img->id, ISO_HPPA_PALO_CMDLEN, 0,
                           "HP-PA PALO command line too long");
            return ISO_HPPA_PALO_CMDLEN;
        }
        memcpy(buf + 1024, img->hppa_cmdline, strlen(img->hppa_cmdline) + 1);
    }
    return ISO_SUCCESS;
}


/**
 * Write DEC Alpha boot sector. See doc/boot_sectors.txt
 *
 * learned from  cdrkit-1.1.10/genisoimage/boot-alpha.c
 * by Steve McIntyre <steve@einval.com>
 *    who states "Heavily inspired by isomarkboot by David Mosberger in 1996"
 *
 */
static int make_dec_alpha_sector(Ecma119Image *t, uint8_t *buf, int flag)
{
    int ret, i;
    IsoImage *img;
    IsoNode *iso_node;
    Ecma119Node *ecma_node;
    uint64_t size, lba, checksum = 0;

    img = t->image;
    if (img->alpha_boot_image == NULL)
        return ISO_SUCCESS;
    ret = boot_nodes_from_iso_path(t, img->alpha_boot_image,
                              &iso_node, &ecma_node, "DEC Alpha boot file", 0);
    if (ret < 0)
        return ret;
    memset(buf, 0, 512);
    strcpy((char *) buf, "Linux/Alpha aboot for ISO filesystem.");
    lba = ecma_node->info.file->sections[0].block * 4;
    size = ecma_node->info.file->sections[0].size / 512 +
           !!(ecma_node->info.file->sections[0].size % 512);
    iso_lsb(buf + 480, size & 0xffffffff, 4);
    iso_lsb(buf + 484, (size >> 32) & 0xffffffff, 4);
    iso_lsb(buf + 488, lba & 0xffffffff, 4);
    iso_lsb(buf + 492, (lba >> 32) & 0xffffffff, 4);
    for (i = 0; i < 63; i++)
       checksum += iso_read_lsb64(buf + 8 * i);
    iso_lsb(buf + 504, checksum & 0xffffffff, 4);
    iso_lsb(buf + 508, (checksum >> 32) & 0xffffffff, 4);
    return ISO_SUCCESS;
}

/* Convenience frontend for iso_register_apm_entry().
   name and type are 0-terminated strings.
*/
int iso_quick_apm_entry(struct iso_apm_partition_request **req_array,
                        int *apm_req_count,
                        uint32_t start_block, uint32_t block_count,
                        char *name, char *type)
{
    int ret, l;
    struct iso_apm_partition_request *entry;

    entry = calloc(1, sizeof(struct iso_apm_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    entry->start_block = start_block;
    entry->block_count = block_count;
    for (l = 0; l < 32 && name[l] != 0; l++);
    if (l > 0)
        memcpy((char *) entry->name, name, l);
    for (l = 0; l < 32 && type[l] != 0; l++);
    if (l > 0)
        memcpy((char *) entry->type, type, l);
    entry->req_status = 0;
    entry->image_path = NULL;
    ret = iso_register_apm_entry(req_array, apm_req_count, entry, 0);
    free(entry);
    return ret;
}


static int iso_find_gpt_entry(struct iso_gpt_partition_request **req_array,
                        int gpt_req_count,
                        uint64_t start_block, uint64_t block_count,
                        int *index, int flag)
{
    struct iso_gpt_partition_request *entry;

    for (*index = 0; *index < gpt_req_count; (*index)++) {
        entry = req_array[*index];
        if (entry->start_block == start_block &&
            entry->block_count == block_count)
            return 1;
    }
    *index = -1;
    return 0;
}


/* Convenience frontend for iso_register_gpt_entry().
   name has to be already encoded as UTF-16LE.
*/
int iso_quick_gpt_entry(struct iso_gpt_partition_request **req_array,
                        int *gpt_req_count,
                        uint64_t start_block, uint64_t block_count,
                        uint8_t type_guid[16], uint8_t partition_guid[16],
                        uint64_t flags, uint8_t name[72])
{
    int ret;
    struct iso_gpt_partition_request *entry;

    entry = calloc(1, sizeof(struct iso_gpt_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    entry->start_block = start_block;
    entry->block_count = block_count;
    memcpy(entry->type_guid, type_guid, 16);
    memcpy(entry->partition_guid, partition_guid, 16);
    entry->flags = flags;
    memcpy(entry->name, name, 72);
    entry->req_status = 0;
    entry->image_path = NULL;
    ret = iso_register_gpt_entry(req_array, gpt_req_count, entry, 0);
    free(entry);
    return ret;
}


int iso_quick_mbr_entry(struct iso_mbr_partition_request **req_array,
                        int *mbr_req_count,
                        uint64_t start_block, uint64_t block_count,
                        uint8_t type_byte, uint8_t status_byte,
                        int desired_slot)
{
    int ret;
    struct iso_mbr_partition_request *entry;

    ret = iso_mbr_entry_slot_is_free(req_array, *mbr_req_count, desired_slot);
    if (ret < 0)
        desired_slot = 0;
    else if (ret == 0)
        return ISO_BOOT_MBR_COLLISION;

    entry = calloc(1, sizeof(struct iso_mbr_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    entry->start_block = start_block;
    entry->block_count = block_count;
    entry->type_byte = type_byte;
    entry->status_byte = status_byte;
    entry->desired_slot = desired_slot;
    entry->image_path = NULL;
    ret = iso_register_mbr_entry(req_array, mbr_req_count, entry, 0);
    free(entry);
    return ret;
}


int iso_mbr_entry_slot_is_free(struct iso_mbr_partition_request **req_array,
                               int mbr_req_count, int slot)
{
    int i;

    if (slot < 0 || slot > ISO_MBR_ENTRIES_MAX)
        return -1;
    if (slot == 0)
        return 1;
    for (i = 0; i < mbr_req_count; i++)
        if (req_array[i]->desired_slot == slot)
            return 0;
    return 1;
}


/**
 * Compare the block interval positions of two iso_apm_partition_request
 */
static
int cmp_partition_request(const void *f1, const void *f2)
{
    struct iso_partition_request {
       uint64_t start_block;
       uint64_t block_count;
    } *r1, *r2;

    r1 = *((struct iso_partition_request **) f1);
    r2 = *((struct iso_partition_request **) f2);
    if (r1->start_block < r2->start_block)
        return -1;
    if (r1->start_block > r2->start_block)
        return 1;

    /* In case of overlapping the largest partition shall be first */
    if (r1->block_count > r2->block_count)
        return -1;
    if (r1->block_count < r2->block_count)
        return 1;
    return 0;
}


/* @param flag bit0= This is the entry in block 1. Its blocks are already in
                     the desired apm_block_size unit. Set block_fac to 1.
                     Set flags to 3 rather than 0x13.
*/
static int iso_write_apm_entry(Ecma119Image *t, int apm_block_size,
                               struct iso_apm_partition_request *req,
                               uint8_t *buf, int map_entries, int flag)
{
    uint8_t *wpt;
    uint32_t flags;
    int block_fac;

    if ((flag & 1) || (t->apm_req_flags & 4))
        block_fac = 1;
    else
        block_fac = 2048 / apm_block_size;
        
    memset(buf, 0, apm_block_size);
    wpt = buf;

    /* Signature */
    wpt[0] = 'P'; wpt[1] = 'M';
    wpt+= 2;
    /* reserved */
    wpt += 2;
    /* Number of partition entries */
    iso_msb(wpt, (uint32_t) map_entries, 4);
    wpt += 4;
    /* Physical block start of partition */
    iso_msb(wpt, (uint32_t) (req->start_block * block_fac), 4);
    wpt += 4;
    /* Physical block count of partition */
    iso_msb(wpt, (uint32_t) (req->block_count * block_fac), 4);
    wpt += 4;
    /* Partition name */
    memcpy(wpt, req->name, 32);
    wpt += 32;
    /* Type string */
    memcpy(wpt, req->type, 32);
    wpt += 32;
    /* Logical block start */
    iso_msb(wpt, (uint32_t) 0, 4);
    wpt += 4;
    /* Logical block count */
    iso_msb(wpt, (uint32_t) (req->block_count * block_fac), 4);
    wpt += 4;
    /* Status flags : bit0= entry is valid , bit1= entry is allocated
                      bit4= partition is readable , bit5= partition is writable
                      bit30= automatic mount (legacy Mac)
    */
    if (flag & 1) {
        flags = 3;
    } else {
        flags = 0x13;
        if (strncmp((char *) req->type, "Apple_HFS", 9) == 0 &&
            req->type[9] == 0)
            flags |= 0x40000000;
    }
    iso_msb(wpt, flags, 4);
    wpt += 4;

    /* boot_block , boot_bytes , processor , reserved : are all 0 */

    return ISO_SUCCESS;
}


/* Sort and fill gaps in requested APM */
static int fill_apm_gaps(Ecma119Image *t, uint32_t img_blocks)
{
    int i, ret, gap_counter = 0, up_to;
    uint32_t part_end, goal, block_fac = 1;
    char gap_name[33];

    if (t->apm_req_flags & 4) {
        if (t->opts->apm_block_size == 0)
            t->opts->apm_block_size = 2048;
        block_fac = 2048 / t->opts->apm_block_size;
    }

    /* Find out whether an entry with start_block <= 1 is requested */
    for (i = 0; i < t->apm_req_count; i++) {
        if (t->apm_req[i]->start_block <= 1)
    break;
    }
    if (i >= t->apm_req_count) {
        ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                  1, 0, "Apple", "Apple_partition_map");
        if (ret < 0)
            return ret;
    }

    qsort(t->apm_req, t->apm_req_count,
        sizeof(struct iso_apm_partition_request *), cmp_partition_request);

    if (t->opts->part_like_isohybrid)
        return 1; /* No filling, only sorting */

    /* t->apm_req_count will grow during the loop */
    up_to = t->apm_req_count + 1;
    for (i = 1; i < up_to; i++) {
        if (i < up_to - 1)
            goal = (uint32_t) t->apm_req[i]->start_block;
        else
            goal = img_blocks * block_fac;
        if (i == 1) {
            /* Description of APM itself */
            /* Actual APM size is not yet known. Protection begins at PVD */
            part_end = 16 * block_fac;
            if (goal < part_end && goal> 1)
                    part_end = goal;
        } else {
            part_end = t->apm_req[i - 1]->start_block +
                       t->apm_req[i - 1]->block_count;
        }
        if (part_end > goal) {
            iso_msg_submit(t->image->id, ISO_BOOT_APM_OVERLAP, 0,
               "Program error: APM partitions %d and %d overlap by %lu blocks",
               i - 1, i, part_end - goal);
            return ISO_BOOT_APM_OVERLAP;
        }

        if (t->apm_req_flags & 2) /* Do not fill gaps */
    continue;

        if (part_end < goal || i == up_to - 1) { /* Always add a final entry */
            sprintf(gap_name, "Gap%d", gap_counter);
            gap_counter++;
            ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                      part_end, goal - part_end,
                                      gap_name, "ISO9660_data");
            if (ret < 0)
                return ret;
            /* Mark as automatically placed filler request */
            t->apm_req[t->apm_req_count - 1]->req_status |= 1;
        }
    }

    /* Merge list of gap partitions with list of already sorted entries */
    if (!(t->apm_req_flags & 2)) /* No gaps were filled */
        qsort(t->apm_req, t->apm_req_count,
            sizeof(struct iso_apm_partition_request *), cmp_partition_request);

    return 1;
}


static int rectify_apm(Ecma119Image *t)
{
    int ret;

#ifdef NIX
    /* Disabled */

    /* <<< ts B20526 : Dummy mock-up */
    if (t->apm_req_count <= 0) {
        /*
        ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                  16, 20, "Test1_name_16_20", "Test1_type");
        / * >>> Caution: Size 90 causes intentional partition overlap error * /
        ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                  30, 90, "BAD_30_90_BAD", "Test1_type");
        */
        ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                  30, 20, "Test1_name_30_20", "Test1_type");
        if (ret < 0)
            return ret;
        ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                                 100, 400, "Test2_name_100_400", "Test2_type");
        if (ret < 0)
            return ret;
    }
#endif /* NIX */

    if (t->apm_req_count == 0)
        return 1;

    if (t->gpt_req_count > 0 &&
        t->opts->apm_block_size != 2048 && t->apm_req_count > 0) {
        iso_msgs_submit(0,
                "GPT and APM requested. APM block size would have to be 2048.",
                        0, "FAILURE", 0);
        return ISO_BOOT_APM_GPT_BSIZE;
    }
    if (t->apm_req_count > 0) {
        ret = fill_apm_gaps(t, t->curblock);
        if (ret < 0)
            return ret;
    }
    return 1;
}


/* flag bit0= do not write Block0
*/
static int iso_write_apm(Ecma119Image *t, uint32_t img_blocks, uint8_t *buf,
                         int flag)
{
    int i, ret;
    uint32_t block_fac = 1;
    /* This is a micro mock-up of an APM Block0
       and also harmless x86 machine code.
    */
    static uint8_t block0_template[8] = {
        0x45, 0x52, 0x02, 0x00, 0xeb, 0x02, 0xff, 0xff
    };

    if (t->apm_req_count <= 0)
        return 2;

    if (t->opts->apm_block_size == 0) {
        /* One cannot be sure that all GPT partitions are registered
           already. So it is necessary to choose the block size which is
           combinable with GPT but not mountable on Linux.
        */
        t->opts->apm_block_size = 2048;
    }

    if (t->apm_req_flags & 4)
        block_fac = 2048 / t->opts->apm_block_size;

    if (!(t->apm_req_flags & 2)) {
        /* Gaps have been filled. Care for the final one */
        /* Adjust last partition to img_size. This size was not known when the
           number of APM partitions was determined.
        */
        if (img_blocks * block_fac <
            t->apm_req[t->apm_req_count - 1]->start_block)
            t->apm_req[t->apm_req_count - 1]->block_count = 0;
        else
            t->apm_req[t->apm_req_count - 1]->block_count =
                                 img_blocks * block_fac -
                                 t->apm_req[t->apm_req_count - 1]->start_block;
        /* If it is still empty, remove it */
        if(t->apm_req[t->apm_req_count - 1]->block_count == 0) {
          free(t->apm_req[t->apm_req_count - 1]);
          t->apm_req_count--;
        }
    }

    /* If block size is larger than 512, then not all 63 entries will fit */
    if ((t->apm_req_count + 1) * t->opts->apm_block_size > 32768) 
        return ISO_BOOT_TOO_MANY_APM;

    /* Block 1 describes the APM itself */
    t->apm_req[0]->start_block = 1;
    t->apm_req[0]->block_count = t->apm_req_count;

    if (!(flag & 1)) {
      /* Write APM block 0. Very sparse, not to overwrite much of
         possible MBR.
      */
      memcpy(buf, block0_template, 8);
      buf[2]= (t->opts->apm_block_size >> 8) & 0xff;
      buf[3]= 0;
    }

    /* Write APM Block 1 to t->apm_req_count */
    for (i = 0; i < t->apm_req_count; i++) {
        ret = iso_write_apm_entry(t, t->opts->apm_block_size, t->apm_req[i],
                     buf + (i + 1) * t->opts->apm_block_size, t->apm_req_count,
                     i == 0);
        if (ret < 0)
            return ret;
    }
    return ISO_SUCCESS;
}


static int iso_write_mbr(Ecma119Image *t, uint32_t img_blocks, uint8_t *buf)
{
    int i, ret, req_of_slot[ISO_MBR_ENTRIES_MAX], q, j;

#ifdef NIX
    /* Disabled */

    /* <<< Dummy mock-up */
    if (t->mbr_req_count <= 0) {
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count),
                                  (uint64_t) 0, (uint64_t) 0, 0xee, 0, 0);
        if (ret < 0)
            return ret;
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count),
                                  ((uint64_t) 100) * 4, (uint64_t) 0,
                                  0x0c, 0x80, 1);
        if (ret < 0)
            return ret;
    }
#endif /* NIX */

    if (t->mbr_req_count <= 0)
        return 2;

    /* >>> Sort by start block ? */

    /* Adjust partition ends */
    for (i = 0; i < t->mbr_req_count; i++) {
        if (i > 0) {
            if (t->mbr_req[i]->start_block <= t->mbr_req[i - 1]->start_block &&
                !(t->mbr_req[i]->block_count == 0 &&
                  t->mbr_req[i]->start_block ==
                                             t->mbr_req[i - 1]->start_block))
                return ISO_BOOT_MBR_OVERLAP;
            if (t->mbr_req[i - 1]->start_block +
                   t->mbr_req[i - 1]->block_count > t->mbr_req[i]->start_block)
                return ISO_BOOT_MBR_OVERLAP;
        }
        if (t->mbr_req[i]->block_count != 0)
    continue;
        if (i < t->mbr_req_count - 1)
            t->mbr_req[i]->block_count = t->mbr_req[i + 1]->start_block -
                                         t->mbr_req[i]->start_block;
        else
            t->mbr_req[i]->block_count = ((uint64_t) img_blocks) * 4 -
                                         t->mbr_req[i]->start_block;
    }

    /* Assign requested entries to slot numbers */
    for (i = 0; i < ISO_MBR_ENTRIES_MAX; i++)
        req_of_slot[i] = -1;
    for (i = 0; i < t->mbr_req_count; i++) {
        if (t->mbr_req[i]->desired_slot < 1 ||
            t->mbr_req[i]->desired_slot > ISO_MBR_ENTRIES_MAX)
    continue;
        if (req_of_slot[t->mbr_req[i]->desired_slot - 1] >= 0)
            return ISO_BOOT_MBR_COLLISION;
        req_of_slot[t->mbr_req[i]->desired_slot - 1] = i;
    }
    for (i = 0; i < t->mbr_req_count; i++) {
        if (t->mbr_req[i]->desired_slot > 0)
    continue;
        for (j = 0; j < ISO_MBR_ENTRIES_MAX; j++)
             if (req_of_slot[j] < 0)
        break;
        if (j >= ISO_MBR_ENTRIES_MAX)
            return ISO_BOOT_TOO_MANY_MBR;
        req_of_slot[j] = i;
    }

    /* Write partition slots */
    for (i = 0; i < ISO_MBR_ENTRIES_MAX; i++) {
        memset(buf + 446 + i * 16, 0, 16);
        q = req_of_slot[i];
        if (q < 0) 
    continue;
        if (t->mbr_req[q]->block_count == 0)
    continue;
        ret = write_mbr_partition_entry(i + 1, (int) t->mbr_req[q]->type_byte,
                  t->mbr_req[q]->start_block, t->mbr_req[q]->block_count,
                  t->partition_secs_per_head, t->partition_heads_per_cyl,
                  buf, 2);
        if (ret < 0)
            return ret;
        buf[446 + i * 16] = t->mbr_req[q]->status_byte;
    }
    return ISO_SUCCESS;
}


static void iso_write_gpt_entry(Ecma119Image *t, uint8_t *buf,
                                uint8_t type_guid[16], uint8_t part_uuid[16],
                                uint64_t start_lba, uint64_t end_lba,
                                uint64_t flags, uint8_t name[72])
{
    char *wpt;
    int i;

    wpt = (char *) buf;
    memcpy(wpt, type_guid, 16);
    wpt += 16;
    for (i = 0; i < 16; i++)
        if (part_uuid[i])
    break;
    if (i == 16) {
        if (!t->gpt_disk_guid_set)
            iso_gpt_uuid(t, t->gpt_disk_guid);
        t->gpt_disk_guid_set = 1;
        iso_gpt_uuid(t, part_uuid);
    }
    memcpy(wpt, part_uuid, 16);
    wpt += 16;
    iso_lsb_to_buf(&wpt, start_lba & 0xffffffff, 4, 0);
    iso_lsb_to_buf(&wpt, (start_lba >> 32) & 0xffffffff, 4, 0);
    iso_lsb_to_buf(&wpt, end_lba & 0xffffffff, 4, 0);
    iso_lsb_to_buf(&wpt, (end_lba >> 32) & 0xffffffff, 4, 0);
    iso_lsb_to_buf(&wpt, flags & 0xffffffff, 4, 0);
    iso_lsb_to_buf(&wpt, (flags >> 32) & 0xffffffff, 4, 0);
    memcpy(wpt, name, 72);
}


int iso_write_gpt_header_block(Ecma119Image *t, uint32_t img_blocks,
                               uint8_t *buf, uint32_t max_entries,
                               uint32_t part_start, uint32_t p_arr_crc)
{
    static char *sig = "EFI PART";
    static char revision[4] = {0x00, 0x00, 0x01, 0x00};
    char *wpt;
    uint32_t crc;
    off_t back_lba;

    memset(buf, 0, 512);
    wpt = (char *) buf;

    /* >>> Make signature adjustable */
    memcpy(wpt, sig, 8); /* no trailing 0 */
    wpt += 8;

    memcpy(wpt, revision, 4);
    wpt += 4;
    iso_lsb_to_buf(&wpt, 92, 4, 0);

    /* CRC will be inserted later */
    wpt += 4;

    /* reserved */
    iso_lsb_to_buf(&wpt, 0, 4, 0);
    /* Own LBA low 32 */
    iso_lsb_to_buf(&wpt, 1, 4, 0);
    /* Own LBA high 32 */
    iso_lsb_to_buf(&wpt, 0, 4, 0);

    /* Backup header LBA is 1 hd block before backup GPT area end */
    back_lba = t->gpt_backup_end * 4 - 1;
    iso_lsb_to_buf(&wpt, (uint32_t) (back_lba & 0xffffffff), 4, 1);
    iso_lsb_to_buf(&wpt, (uint32_t) (back_lba >> 32), 4, 1);

    /* First usable LBA for partitions (4 entries per hd block) */
    iso_lsb_to_buf(&wpt, part_start + max_entries / 4, 4, 0);
    iso_lsb_to_buf(&wpt, 0, 4, 0);

    /* Last usable LBA for partitions is 1 hd block before first backup entry*/
    iso_lsb_to_buf(&wpt,
                   (uint32_t) ((back_lba - max_entries / 4 - 1) & 0xffffffff),
                   4, 1);
    iso_lsb_to_buf(&wpt,
                   (uint32_t) ((back_lba - max_entries / 4 - 1) >> 32), 4, 1);

    /* Disk GUID */
    if (!t->gpt_disk_guid_set)
        iso_gpt_uuid(t, t->gpt_disk_guid);
    t->gpt_disk_guid_set = 1;
    memcpy(wpt, t->gpt_disk_guid, 16);
    wpt += 16;

    /* Partition entries start */
    iso_lsb_to_buf(&wpt, part_start, 4, 0);
    iso_lsb_to_buf(&wpt, 0, 4, 0);

    /* Number of partition entries */
    iso_lsb_to_buf(&wpt, max_entries, 4, 0);

    /* Size of a partition entry */
    iso_lsb_to_buf(&wpt, 128, 4, 0);

    /* CRC-32 of the partition array */
    iso_lsb_to_buf(&wpt, p_arr_crc, 4, 0);


    /* <<< Only for a first test */
    if (wpt - (char *) buf != 92) {
        iso_msgs_submit(0,
                   "program error : write_gpt_header_block : wpt != 92",
                   0, "FATAL", 0);
        return ISO_ISOLINUX_CANT_PATCH;
    }

    /* CRC-32 of this header while head_crc is 0 */
    crc = iso_crc32_gpt((unsigned char *) buf, 92, 0); 
    wpt = ((char *) buf) + 16;
    iso_lsb_to_buf(&wpt, crc, 4, 0);

    return ISO_SUCCESS;
}


/* Only for up to 36 characters ISO-8859-1 (or ASCII) input */
void iso_ascii_utf_16le(uint8_t gap_name[72])
{
    int i;

    for (i = strlen((char *) gap_name) - 1; i >= 0; i--) {
        gap_name[2 * i] = gap_name[i];
        gap_name[2 * i + 1] = 0;
    }
}


static int intvl_overlap(uint64_t start1, uint64_t end1,
                         uint64_t start2, uint64_t end2, int second)
{
    if (start1 >= start2 && start1 <= end2)
        return 1;
    if (end1 >= start2 && end1 <= end2)
        return 1;
    if (!second)
        return intvl_overlap(start2, end2, start1, end1, 1);
    return 0;
}


/* Check APM HFS+ partitions whether they would fit in gaps.
   If so, add them as GPT partitions, too.
 */
static int iso_copy_apmhfs_to_gpt(Ecma119Image *t, int flag)
{
    int a, i, counter = 0, ret;
    uint64_t bfac = 4;
    static uint8_t hfs_plus_uuid[16] = {
        0x00, 0x53, 0x46, 0x48, 0x00, 0x00, 0xaa, 0x11,
        0xaa, 0x11, 0x00, 0x30, 0x65, 0x43, 0xec, 0xac
    };
    static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    uint8_t gpt_name[72];
    static uint64_t gpt_flags = (((uint64_t) 1) << 60) | 1;

    if ((t->apm_req_flags & 4) && t->opts->apm_block_size / 512 > 0)
        bfac = t->opts->apm_block_size / 512;

    for (a = 0; a < t->apm_req_count; a++) {
        if (strcmp((char *) t->apm_req[a]->type, "Apple_HFS") != 0)
    continue;
        for (i = 0; i < t->gpt_req_count; i++)
            if (intvl_overlap(t->apm_req[a]->start_block * bfac,
                              (t->apm_req[a]->start_block +
                               t->apm_req[a]->block_count - 1) * bfac,
                              t->gpt_req[i]->start_block,
                              t->gpt_req[i]->start_block +
                              t->gpt_req[i]->block_count - 1, 0))
        break;
        if (i >= t->gpt_req_count) {
            memset(gpt_name, 0, 72);
            counter++;
            if (counter > 1)
                sprintf((char *) gpt_name, "HFSPLUS_%d", counter);
            else
                sprintf((char *) gpt_name, "HFSPLUS");
            iso_ascii_utf_16le(gpt_name);
            ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                      t->apm_req[a]->start_block * bfac,
                                      t->apm_req[a]->block_count * bfac,
                                      hfs_plus_uuid, zero_uuid,
                                      gpt_flags, gpt_name);
            if (ret < 0)
                return ret;
        }
    }
    return 1;
}


static int iso_write_gpt(Ecma119Image *t, uint32_t img_blocks, uint8_t *buf)
{
    static uint8_t basic_data_uuid[16] = {
        0xa2, 0xa0, 0xd0, 0xeb, 0xe5, 0xb9, 0x33, 0x44,
        0x87, 0xc0, 0x68, 0xb6, 0xb7, 0x26, 0x99, 0xc7
    };

    uint8_t *wpt;
    uint32_t p_arr_crc = 0;
    uint64_t start_lba, end_lba, goal, part_end, next_end, backup_end_lba;
    uint64_t eff_gpt_flags;
    int ret, i, gap_counter = 0, up_to, slot, j, to_insert;
    struct iso_gpt_partition_request *req;
    char msg[81];
    uint8_t gpt_name[72];
    static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    static uint8_t *type_guid;
    static uint64_t gpt_flags = (((uint64_t) 1) << 60) | 1;

    if (t->gpt_req_count == 0)
        return 2;
    backup_end_lba = ((uint64_t) t->gpt_backup_end - t->gpt_backup_size) * 4;

    ret = iso_copy_apmhfs_to_gpt(t, 0);
    if (ret <= 0)
        return ret;

    if (t->opts->partition_offset == 16 && (t->opts->iso_gpt_flag & 2) &&
        !(t->opts->iso_gpt_flag & 8)) {
        /* If there is no appended partition number 1, the space between
           t->opts->partition_offset and t->vol_space_size is uncovered,
           and t->opts->partition_offset == 16:
           Create ISO9660 partitition (see below)
        */
        for (i = 0; i < t->gpt_req_count; i++) {
            if (t->gpt_req[i]->desired_slot == 1)
        break;
            if (t->gpt_req[i]->start_block < t->vol_space_size * (uint64_t) 4
                &&
                t->gpt_req[i]->start_block + t->gpt_req[i - 1]->block_count >
                t->opts->partition_offset * (uint64_t) 4)
        break;
        }
        if (i >= t->gpt_req_count) {
            /* Create ISO 9660 partition */
            memset(gpt_name, 0, 72);
            type_guid = basic_data_uuid;
            eff_gpt_flags= gpt_flags;
            sprintf((char *) gpt_name, "ISO9660");
            type_guid = basic_data_uuid;
            if (t->opts->iso_gpt_flag & 1)
                type_guid = t->opts->iso_gpt_type_guid;
            if (t->system_area_options & (1 << 16))
                eff_gpt_flags|= 4; /* Legacy BIOS bootable */
            if (t->system_area_options & (1 << 17))
                eff_gpt_flags&= ~(((uint64_t) 1) << 60);/* Not read-only */
            iso_ascii_utf_16le(gpt_name);
            ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                    t->opts->partition_offset * (uint64_t) 4,
                                    (t->vol_space_size -
                                     t->opts->partition_offset) * (uint64_t) 4,
                                    type_guid, zero_uuid,
                                    eff_gpt_flags, gpt_name);
            if (ret < 0)
                return ret;
            t->gpt_req[t->gpt_req_count - 1]->desired_slot = 1;
            /* Make new partition the first one */
            req= t->gpt_req[t->gpt_req_count - 1];
            for (i = t->gpt_req_count - 2; i >= 0; i--)
                t->gpt_req[i + 1]= t->gpt_req[i];
            t->gpt_req[0]= req;
        }
    }

    /* Sort and fill gaps */

    /* Sort if not gap filling is disabled or not sorting is disabled */
    if (!((t->opts->iso_gpt_flag & 2) && (t->opts->iso_gpt_flag & 4))) {
        qsort(t->gpt_req, t->gpt_req_count,
            sizeof(struct iso_gpt_partition_request *), cmp_partition_request);
    }
    /* t->gpt_req_count will grow during the loop */
    up_to = t->gpt_req_count + 1;
    goal = 0;
    part_end = 0;

    if (t->opts->part_like_isohybrid || t->opts->iso_gpt_flag & 2)
        up_to = 0; /* No gap filling */

    for (i = 0; i < up_to; i++) {
        if (i < up_to - 1) {
            goal = t->gpt_req[i]->start_block;
        } else {
            goal = ((uint64_t) img_blocks) * 4;
            if (goal > backup_end_lba)
                goal = backup_end_lba;
        }
        if (i == 0) {
            if (goal <= 16 * 4)
    continue;
            next_end = 16 * 4;
        } else {
            next_end = t->gpt_req[i - 1]->start_block +
                       t->gpt_req[i - 1]->block_count;
        }
        if (next_end > part_end)
            part_end = next_end;
        if (part_end > goal) {
            if (!(t->gpt_req_flags & 1)) {
                iso_msg_submit(t->image->id, ISO_BOOT_GPT_OVERLAP, 0,
               "Program error: GPT partitions %d and %d overlap by %.f blocks",
                               i - 1, i, (double) (part_end - goal));
                return ISO_BOOT_GPT_OVERLAP;
            }
        } else if (part_end < goal) {
            memset(gpt_name, 0, 72);
            type_guid = basic_data_uuid;
            eff_gpt_flags= gpt_flags;
            if (goal == t->vol_space_size * (uint64_t) 4 &&
                part_end == t->opts->partition_offset * (uint64_t) 4) {
                sprintf((char *) gpt_name, "ISO9660");
                if (t->opts->iso_gpt_flag & 1)
                    type_guid = t->opts->iso_gpt_type_guid;
                if (t->system_area_options & (1 << 16))
                    eff_gpt_flags|= 4; /* Legacy BIOS bootable */
                if (t->system_area_options & (1 << 17))
                    eff_gpt_flags&= ~(((uint64_t) 1) << 60);/* Not read-only */
            } else {
                sprintf((char *) gpt_name, "Gap%d", gap_counter);
            }
            iso_ascii_utf_16le(gpt_name);
            gap_counter++;
            ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                      part_end, goal - part_end,
                                      type_guid, zero_uuid,
                                      eff_gpt_flags, gpt_name);
            if (ret < 0)
                return ret;
            /* Mark as automatically placed filler request */
            t->gpt_req[t->gpt_req_count - 1]->req_status |= 1;
        }
    }
    if (!((t->opts->iso_gpt_flag & 2) && (t->opts->iso_gpt_flag & 4))) {
        /* Merge list of gap partitions with list of already sorted entries */
        qsort(t->gpt_req, t->gpt_req_count,
            sizeof(struct iso_gpt_partition_request *), cmp_partition_request);
    }
 
    if ((int) t->gpt_max_entries < t->gpt_req_count)
        return ISO_BOOT_TOO_MANY_GPT;

    /* Write the GPT entries to buf */
    wpt= buf + 512 * t->gpt_part_start;
    slot= 1;
    for (i = 0; i < t->gpt_req_count; i++) {
        req = t->gpt_req[i];
        start_lba = req->start_block;
        end_lba = req->start_block + req->block_count;
        if (req->start_block == t->opts->partition_offset * ((uint64_t) 4) &&
            req->block_count == ((uint64_t) 4) * 0xffffffff)
            end_lba = t->vol_space_size * 4;
        if (end_lba > backup_end_lba)
            end_lba = backup_end_lba;
        end_lba = end_lba - 1;
        if (req->desired_slot > 0) {
            to_insert= req->desired_slot - slot;
            if (to_insert > 0 &&
                slot - 1 + to_insert + t->gpt_req_count - i <=
                                                    (int) t->gpt_max_entries) {
                /* There is need and room to insert empty partition entries */
                for (j = 0; j < to_insert; j++) {
                    memset(wpt, 0, 128);
                    wpt+= 128;
                    slot++;
                }
		if (!t->wthread_is_running) {
                    sprintf(msg,
                    "Inserted %d empty GPT slots before appended partition %d",
                            to_insert, req->desired_slot);
                    iso_msgs_submit(0, msg, 0, "DEBUG", 0);
                }
            } else if (slot != req->desired_slot) {
		if (!t->wthread_is_running) {
                    sprintf(msg,
              "Appended GPT partition becomes number %d instead of desired %d",
                            i + 1, req->desired_slot);
                    iso_msgs_submit(0, msg, 0, "NOTE", 0);
                }
            }
        }
        iso_write_gpt_entry(t, wpt, req->type_guid, req->partition_guid, 
                            start_lba, end_lba, req->flags, req->name);
        wpt+= 128;
        slot++;
    }
    for (i= slot - 1; i < (int) t->gpt_max_entries; i++)
        memset(buf + 512 * t->gpt_part_start + 128 * i, 0, 128);

    p_arr_crc = iso_crc32_gpt((unsigned char *) buf + 512 * t->gpt_part_start,
                              128 * t->gpt_max_entries, 0);
    ret = iso_write_gpt_header_block(t, img_blocks, buf + 512,
                                     t->gpt_max_entries,
                                     t->gpt_part_start, p_arr_crc);
    if (ret < 0)
        return ret;
    return ISO_SUCCESS;
}


/* Add a dummy MBR partition of type 0 with boot flag */
static void iso_dummy_mbr_partition(uint8_t *buf, int mode)
{
    int i;
                             /* bootable , start 0/0/1, type 0x00, end 0/0/1,
                                start LBA 0, block count 1 */
    static uint8_t dummy_entry[16] = {
                              0x80, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x00,
                              0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00 };

    for (i = 0; i < 4; i++) {
        if (mbr_part_slot_is_unused(buf + 446 + 16 * i)) {
            memcpy(buf + 446 + 16 * i, dummy_entry, 16);
            return;
        }
    }
    /* Abundance of 0xee and 0xef partitions. No other one free. */
    for (i = 0; i < 4; i++) {
        if (buf[446 + 16 * i + 4] != 0xef) {
            buf[446 + 16 * i] |= 0x80;
            return;
        }
    }
    i = 3;
    buf[446 + 16 * i] |= 0x80;
}


/* flag bit0= only accept partition 1 as match for partition_offset
*/
static
int iso_ensure_mbr_part_table(Ecma119Image *t, uint32_t img_blocks,
                              uint8_t *buf, int flag)
{
    int part_type, ret, i, found_part = 0;
    uint32_t start_lba, num_blocks;

    /* Look for MBR partition which starts at t->opts->partition_offset * 4
       and has non-zero length
    */
    if (buf[510] == 0x55 && buf[511] == 0xaa &&
        t->opts->partition_offset < 0x3fffffff && img_blocks < 0x3fffffff ) {
        for (i = 0; i < 4; i++) {
            start_lba = iso_read_lsb(buf + 446 + i * 16 + 8, 4);
            num_blocks = iso_read_lsb(buf + 446 + i * 16 + 12, 4);
            if (t->opts->partition_offset * 4 == start_lba && num_blocks > 0) {
                found_part = i + 1;
        break;
            }
            if (flag & 1)
        break;
        }
    }
    if (found_part > 0) {
        /* Update size fields in found_part */
        part_type = buf[446 + (found_part - 1) * 16 + 4];
        if (t->opts->iso_mbr_part_type >= 0 &&
            t->opts->iso_mbr_part_type <= 255)
            part_type= t->opts->iso_mbr_part_type;
        ret = write_mbr_partition_entry(found_part, part_type, 
                                        start_lba, img_blocks * 4,
                                        t->partition_secs_per_head,
                                        t->partition_heads_per_cyl, buf, 2);
    } else {
        part_type = 0xcd;
        if (t->opts->iso_mbr_part_type >= 0 &&
            t->opts->iso_mbr_part_type <= 255)
            part_type= t->opts->iso_mbr_part_type;
        ret = make_grub_msdos_label(img_blocks, t->partition_secs_per_head,
                                    t->partition_heads_per_cyl,
                                    (uint8_t) part_type, buf, 2);
    }
    if (ret != ISO_SUCCESS) /* error should never happen */
        return ISO_ASSERT_FAILURE;
    return ISO_SUCCESS;
}


/* @param flag
          bit0= t->opts->ms_block is not counted in t->total_size
*/
int iso_write_system_area(Ecma119Image *t, uint8_t *buf, int flag)
{
    int ret, int_img_blocks, sa_type, i, will_append = 0, do_isohybrid = 0;
    int first_partition = 1, last_partition = 4, apm_flag, part_type = 0;
    int gpt_count = 0, gpt_idx[128], apm_count = 0, no_boot_mbr = 0;
    int offset_flag = 0, risk_of_ee = 0;
    uint32_t img_blocks, gpt_blocks, mbrp1_blocks, pml_blocks;
    uint64_t blk;
    uint8_t *wpt;

    if ((t == NULL) || (buf == NULL)) {
        return ISO_NULL_POINTER;
    }

    /* set buf to 0s */
    memset(buf, 0, 16 * BLOCK_SIZE);

    sa_type = (t->system_area_options >> 2) & 0x3f;

    iso_tell_max_part_range(t->opts, &first_partition, &last_partition, 0);
    for (i = first_partition - 1; i <= last_partition - 1; i++)
        if (t->opts->appended_partitions[i] != NULL) {
            will_append = 1;
    break;
        }

#ifdef Libisofs_appended_partitions_inlinE
    img_blocks = t->vol_space_size;
#else
    img_blocks = t->curblock;
#endif

    if (t->system_area_data != NULL) {
        /* Write more or less opaque boot image */
        memcpy(buf, t->system_area_data, 16 * BLOCK_SIZE);

    } else if (sa_type == 0 && t->catalog != NULL &&
               (t->catalog->bootimages[0]->isolinux_options & 0x0a) == 0x02) {
        /* Check for isolinux image with magic number of 3.72 and produce
           an MBR from our built-in template. (Deprecated since 31 Mar 2010)
        */
        if (t->bootsrc[0] == NULL)
            return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
      "Cannot refer by isohybrid MBR to data outside of ISO 9660 filesystem.");
        if (img_blocks < 0x80000000) {
            int_img_blocks= img_blocks;
        } else {
            int_img_blocks= 0x7ffffff0;
        }
        ret = make_isohybrid_mbr(t->bootsrc[0]->sections[0].block,
                                 &int_img_blocks, (char*)buf, 0);
        if (ret != 1) {
            /* error, it should never happen */
            return ISO_ASSERT_FAILURE;
        }
        return ISO_SUCCESS;
    }

    /* If APM entries were submitted to iso_register_apm_entry(), then they
       get sprinkled over the system area after the system area template was
       loaded and before any other data get inserted.
       Note that if APM and MBR get combined, then the first 8 bytes of the MBR
       template must be replaceable by:
          {0x45, 0x52, 0x08 0x00, 0xeb, 0x02, 0xff, 0xff}

       >>> ts B20526
       >>> This does not care for eventual image enlargements in last minute.
       >>> A sa_type, that does this, will have to adjust the last APM entry
       >>> if exactness matters.
    */

    apm_flag = 0;
    if (sa_type == 0 && ((t->system_area_options & 3) == 2 ||
                          t->opts->part_like_isohybrid)) {
        if (sa_type == 0 && (t->system_area_options & 3) == 2)
            do_isohybrid = 1;

        /* >>> Coordinate with partprepend writer */
        /* <<< provisory trap */
        if (t->mbr_req_count > 0)
            return ISO_BOOT_MBR_OVERLAP;

        /* If own APM is desired, set flag bit0 to prevent writing of Block0
           which would interfere with the own Block0 of isohybrid.
        */
        ret = assess_isohybrid_gpt_apm(t, &gpt_count, gpt_idx, &apm_count, 0);
        if (ret < 0)
            return ret;
        if (apm_count > 0)
            apm_flag |= 1;
    }

    ret = iso_write_apm(t, img_blocks, buf, apm_flag);
    if (ret < 0) {
        iso_msg_submit(t->image->id, ret, 0,
                       "Cannot set up Apple Partition Map");
        return ret;
    }
    ret = iso_write_mbr(t, img_blocks, buf);
    if (ret < 0) {
        iso_msg_submit(t->image->id, ret, 0,
                       "Cannot set up MBR partition table");
        return ret;
    }
    if (t->mbr_req_count > 0) {
        if (sa_type != 0)
            return ISO_NON_MBR_SYS_AREA;
        risk_of_ee = 1;
    }

    if (t->gpt_backup_outside)
        gpt_blocks = t->total_size / BLOCK_SIZE +
                     (flag & 1) * t->opts->ms_block;
    else
        gpt_blocks = img_blocks;
    ret = iso_write_gpt(t, gpt_blocks, buf);
    if (ret < 0) {
        iso_msg_submit(t->image->id, ret, 0, "Cannot set up GPT");
        return ret;
    }

    if (sa_type == 0 && (t->system_area_options & 1)) {
        if (t->mbr_req_count == 0){
            /* Write GRUB protective msdos label, i.e. a simple partition
               table */
            if (t->gpt_req_count > 0 && ! t->opts->part_like_isohybrid) {
                part_type = 0xee;
                pml_blocks = gpt_blocks;
            } else {
                part_type = 0xcd;
                if (t->opts->iso_mbr_part_type >= 0 &&
                    t->opts->iso_mbr_part_type <= 255)
                    part_type= t->opts->iso_mbr_part_type;
                pml_blocks = img_blocks;
            }
            ret = make_grub_msdos_label(pml_blocks, t->partition_secs_per_head,
                                        t->partition_heads_per_cyl,
                                        (uint8_t) part_type, buf, 0);
            if (ret != ISO_SUCCESS) /* error should never happen */
               return ISO_ASSERT_FAILURE;
            risk_of_ee = 1;
        } else if (t->gpt_req_count > 0) {

           /* >>> ??? change first partition type to 0xee */;

        }
    } else if (do_isohybrid || t->opts->part_like_isohybrid) {
        /* Patch externally provided system area as isohybrid MBR
           or at least write an MBR partition table as of isohybrid
        */
        if ((t->catalog == NULL || t->system_area_data == NULL) &&
            do_isohybrid) {
            /* isohybrid makes only sense together with ISOLINUX boot image
               and externally provided System Area.
            */
            return ISO_ISOLINUX_CANT_PATCH;
        }

        if (gpt_count > 0 || apm_count > 0) {
            /* Decision can be revoked in make_isolinux_mbr if !do_isohybrid */
            part_type = 0x00;
        } else {
            part_type = 0x17;
        }
        /* By tradition, real isohybrid insists in 0x00 if GPT or APM */
        if (part_type != 0x00 || !do_isohybrid)
            if (t->opts->iso_mbr_part_type >= 0 &&
                t->opts->iso_mbr_part_type <= 255)
                part_type= t->opts->iso_mbr_part_type;

        if (t->opts->appended_as_gpt && t->have_appended_partitions) {
            part_type = 0xee;
            risk_of_ee = 1;
            img_blocks = gpt_blocks;
            no_boot_mbr = 2;
        }

        /* ??? Why was partition_offset 0 here ?
               It gets adjusted later by iso_offset_partition_start()
               Does it harm to give the real offset here ?
           Now this is really needed for checking whether partitions
           are inside the ISO 9660 partition if !do_isohybrid
        */
        ret = make_isolinux_mbr(&img_blocks, t, t->opts->partition_offset * 4,
                                1, part_type, buf,
                                1 | no_boot_mbr | ((!do_isohybrid) << 2) |
                                ((!do_isohybrid) << 3));
        if (ret != 1)
            return ret;
    } else if (sa_type == 1) {
        ret = make_mips_volume_header(t, buf, 0);
        if (ret != ISO_SUCCESS)
            return ret;
    } else if (sa_type == 2) {
        ret = make_mipsel_boot_block(t, buf, 0);
        if (ret != ISO_SUCCESS)
            return ret;
    } else if (sa_type == 3) {
        ret = make_sun_disk_label(t, buf, 0);
        if (ret != ISO_SUCCESS)
            return ret;
    } else if (sa_type == 4 || sa_type == 5) {
        /* (By coincidence, sa_type and PALO header versions match) */
        ret = make_hppa_palo_sector(t, buf, sa_type, 0);
        if (ret != ISO_SUCCESS)
            return ret;
    } else if (sa_type == 6) {
        ret = make_dec_alpha_sector(t, buf, 0);
        if (ret != ISO_SUCCESS)
            return ret;
    } else if ((t->opts->partition_offset > 0 || will_append) &&
               sa_type == 0 && t->mbr_req_count == 0) {
        ret= iso_ensure_mbr_part_table(t, img_blocks, buf,
                  ((t->opts->appended_as_gpt && t->have_appended_partitions) ||
                   t->opts->partition_offset == 0));
        if (ret != ISO_SUCCESS) /* error should never happen */
            return ISO_ASSERT_FAILURE;
        risk_of_ee = 1;
        if (t->opts->appended_as_gpt && t->have_appended_partitions) {

            /* >>> ??? Do this in any case of  t->gpt_req_count > ? */;

            /* Re-write partition entry 1 : protective MBR for GPT */
            part_type = 0xee;
            risk_of_ee = 1;
            ret = write_mbr_partition_entry(1, part_type,
                        (uint64_t) 1, ((uint64_t) gpt_blocks) * 4 - 1, 
                        t->partition_secs_per_head, t->partition_heads_per_cyl,
                        buf, 2);
            if (ret < 0)
                return ret;
        } else if (t->opts->partition_offset == 0) {
            /* Re-write partition entry 1 : start at 0, type Linux */
            blk = ((uint64_t) img_blocks) * 4 - t->post_iso_part_pad / 512;
            part_type = 0x83;
            if (t->opts->iso_mbr_part_type >= 0 &&
                t->opts->iso_mbr_part_type <= 255)
                part_type= t->opts->iso_mbr_part_type;
            ret = write_mbr_partition_entry(1, part_type, (uint64_t) 0, blk,
                        t->partition_secs_per_head, t->partition_heads_per_cyl,
                        buf, 2);
            if (ret < 0)
                return ret;
        }
    }

    /* Check for protective MBR in mbr_req and adjust to GPT size */
    if (t->gpt_req_count > 0 && sa_type == 0 && t->mbr_req_count == 1) {
        if (t->mbr_req[0]->type_byte == 0xee && buf[450] == 0xee &&
            t->mbr_req[0]->desired_slot <= 1) {
            part_type = 0xee;
            risk_of_ee = 1;
            ret = write_mbr_partition_entry(1, part_type,
                        (uint64_t) 1, ((uint64_t) gpt_blocks) * 4 - 1, 
                        t->partition_secs_per_head, t->partition_heads_per_cyl,
                        buf, 2);
            if (ret < 0)
                return ret;
        }
    }

    if (t->opts->partition_offset > 0 && sa_type == 0 &&
        t->mbr_req_count == 0) {
        /* Adjust partition table to partition offset.
           With t->mbr_req_count > 0 this has already been done,
        */

#ifndef Libisofs_appended_partitions_inlinE

        img_blocks = t->curblock;          /* value might have been altered */

#else

        /* A change of t->curblock does not matter in this case */

#endif

        if (part_type == 0xee && t->gpt_req_count > 0) {
            mbrp1_blocks = t->total_size / BLOCK_SIZE +
                           (flag & 1) * t->opts->ms_block;
            offset_flag |= 2 | 1; /* protective MBR, no other partitions */
        } else {
            mbrp1_blocks = img_blocks;
        }
        ret = iso_offset_partition_start(mbrp1_blocks, t->post_iso_part_pad,
                                         t->opts->partition_offset,
                                         t->partition_secs_per_head,
                                         t->partition_heads_per_cyl, buf,
                                         offset_flag);
        if (ret != ISO_SUCCESS) /* error should never happen */
            return ISO_ASSERT_FAILURE;
    }

    /* This possibly overwrites the non-mbr_req partition table entries
       made so far. Overwriting those from t->mbr_req is not allowed.
    */
    if (sa_type == 3 ||
        !(t->opts->appended_as_gpt || t->opts->appended_as_apm)) {
        for (i = first_partition - 1; i <= last_partition - 1; i++) {
            if (t->opts->appended_partitions[i] == NULL)
        continue;
            if (i < t->mbr_req_count)
                return ISO_BOOT_MBR_COLLISION;
            if (sa_type == 3) {
                ret = write_sun_partition_entry(i + 1,
                        t->opts->appended_partitions,
                        t->appended_part_start, t->appended_part_size,
                        ISO_SUN_CYL_SIZE,
                        buf, t->opts->appended_partitions[i][0] == 0);
            } else {
                ret = write_mbr_partition_entry(i + 1,
                        t->opts->appended_part_types[i],
                        (uint64_t) t->appended_part_start[i],
                        (uint64_t) t->appended_part_size[i],
                        t->partition_secs_per_head, t->partition_heads_per_cyl,
                        buf, 0);
            }
            if (ret < 0)
                return ret;
        }
    }

    if (sa_type == 0 && (t->system_area_options & 0x4000) && !do_isohybrid) {
        /* Patch MBR for GRUB2 */
	if (t->num_bootsrc <= 0)
            return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
                          "No boot image found as jump target for GRUB2 MBR.");
        if (t->bootsrc[0] == NULL)
            return iso_msg_submit(t->image->id, ISO_BOOT_IMAGE_NOT_VALID, 0,
          "Cannot refer by GRUB2 MBR to data outside of ISO 9660 filesystem.");
        blk = t->bootsrc[0]->sections[0].block * 4 +
                                                Libisofs_grub2_mbr_patch_offsT;
        wpt = buf + Libisofs_grub2_mbr_patch_poS;
        for (i = 0; i < 8; i++)
             wpt[i] = blk >> (i * 8);
    }

    /* Prevent partition type 0xee if no GPT emerged */

    /* >>> ??? check for GPT magic number at byte 512 ff. ? */;

    if (sa_type == 0 && ((t->system_area_options & 3) || risk_of_ee) &&
        (t->opts->part_like_isohybrid || t->gpt_req_count == 0) &&
        t->opts->iso_mbr_part_type != 0xee) {
        for (i = 0; i < 4; i++) {
            if (buf[446 + 16 * i + 4] == 0xee) {
                iso_msgs_submit(0,
                            "Prevented partition type 0xEE in MBR without GPT",
                            0, "WARNING", 0);
                part_type = 0xcd;
                if (t->opts->iso_mbr_part_type >= 0 &&
                    t->opts->iso_mbr_part_type <= 255)
                    part_type= t->opts->iso_mbr_part_type;
                buf[446 + 16 * i + 4] = (uint8_t) part_type;
            }
        }
    }

    if (sa_type == 0 && (
        (t->system_area_options & 3) ||
        (t->system_area_options & (1 << 14)) ||
        (((t->system_area_options >> 10) & 15) != 1 &&
         (t->system_area_options & (1 << 15)))
        )) {
        /* This is an MBR which shall have a bootable/active flag
           protective-msdos-label, isohybrid, grub2-mbr, mbr-force-bootable
         */
        for (i = 0; i < 4; i++)
            if (buf[446 + 16 * i] & 0x80)
        break;
        if (i >= 4) { /* no bootable/active flag set yet */
            for (i = 0; i < 4; i++) {
                if ((!mbr_part_slot_is_unused(buf + 446 + 16 * i)) &&
                    buf[446 + 16 * i + 4] != 0xee &&
                    buf[446 + 16 * i + 4] != 0xef) {
                    buf[446 + 16 * i] |= 0x80;
            break;
                }
            }
            if (i >= 4) { /* still no bootable/active flag set */
                if (t->system_area_options & (1 << 15)) /* Force it */
                    iso_dummy_mbr_partition(buf, 0);
            }
        }
    }

    if ((((t->system_area_options >> 2) & 0x3f) == 0 &&
         (t->system_area_options & 3) == 1) ||
        t->opts->partition_offset > 0) {
        /* Protective MBR || partition offset
           ISO will not be a partition or add-on session.
           It can span the whole image.
        */
        t->pvd_size_is_total_size = 1;
    }

    return ISO_SUCCESS;
}

/* Choose *heads_per_cyl so that
   - *heads_per_cyl * secs_per_head * 1024 >= imgsize / 512
   - *heads_per_cyl * secs_per_head is divisible by 4
   - it is as small as possible (to reduce alignment overhead)
   - it is <= 255
   @return 1= success , 0= cannot achieve goals
*/
static
int try_sph(off_t imgsize, int secs_per_head, int *heads_per_cyl, int flag)
{
    off_t hd_blocks, hpc;

    hd_blocks= imgsize / 512;
    hpc = hd_blocks / secs_per_head / 1024;
    if (hpc * secs_per_head * 1024 < hd_blocks)
        hpc++;
    if ((secs_per_head % 4) == 0) {
        ;
    } else if ((secs_per_head % 2) == 0) {
        hpc += (hpc % 2);
    } else if(hpc % 4) {
        hpc += 4 - (hpc % 4);
    }
    if (hpc > 255)
        return 0;
    *heads_per_cyl = hpc;
    return 1;
}

int iso_align_isohybrid(Ecma119Image *t, int flag)
{
    int sa_type, ret, always_align;
    uint32_t img_blocks;
    off_t imgsize, cylsize = 0, frac;
    char *msg = NULL;

#ifdef Libisofs_part_align_writeR
    int fap, lap, app_part_count;
#endif

    LIBISO_ALLOC_MEM(msg, char, 160);
    sa_type = (t->system_area_options >> 2) & 0x3f;
    if (sa_type != 0)
        {ret = ISO_SUCCESS; goto ex;}
    always_align = (t->system_area_options >> 8) & 3;

    if (!t->gpt_backup_outside) {
        /* Take into account the backup GPT */;
        ret = precompute_gpt(t);
        if (ret < 0)
            goto ex;
    }

#ifdef Libisofs_part_align_writeR

    /* If partitions get appended then t->opts->tail_blocks and
       t->gpt_backup_size come after the alignment padding.
    */
    app_part_count = iso_count_appended_partitions(t, &fap, &lap);
    img_blocks = t->curblock;
    if (app_part_count == 0)
        img_blocks += t->opts->tail_blocks + t->gpt_backup_size;

#else

    img_blocks = t->curblock + t->opts->tail_blocks + t->gpt_backup_size;

#endif

    imgsize = ((off_t) img_blocks) * (off_t) 2048;
    if ((!(t->opts->appended_as_gpt && t->have_appended_partitions))
        && ((t->system_area_options & 3) || always_align)
        && (off_t) (t->partition_heads_per_cyl * t->partition_secs_per_head
                    * 1024) * (off_t) 512 < imgsize) {
        /* Choose small values which can represent the image size */
        /* First try 32 sectors per head */
        ret = try_sph(imgsize, 32, &(t->partition_heads_per_cyl), 0);
        if (ret == 1) {
            t->partition_secs_per_head = 32;
        } else {
            /* Did not work with 32. Try 63 */
            t->partition_secs_per_head = 63;
            ret = try_sph(imgsize, 63, &(t->partition_heads_per_cyl), 0);
            if (ret != 1)
                t->partition_heads_per_cyl = 255;
        }
        cylsize = t->partition_heads_per_cyl * t->partition_secs_per_head *512;
        frac = imgsize % cylsize;
        sprintf(msg, "Automatically adjusted MBR geometry to %d/%d/%d",
                      (int) (imgsize / cylsize + !!frac),
                      t->partition_heads_per_cyl, t->partition_secs_per_head);
        iso_msgs_submit(0, msg, 0, "NOTE", 0);
    }

    if (always_align == 2)
        {ret = ISO_SUCCESS; goto ex;}

    cylsize = 0;
    if (t->catalog != NULL &&
               (t->catalog->bootimages[0]->isolinux_options & 0x0a) == 0x02) {
        /* Check for isolinux image with magic number of 3.72 and produce
           an MBR from our built-in template. (Deprecated since 31 Mar 2010)
        */
        if (img_blocks >= 0x40000000)
            {ret = ISO_SUCCESS; goto ex;}
        cylsize = 64 * 32 * 512;

    } else if (t->system_area_options & 2) {
        /* Patch externally provided system area as isohybrid MBR */
        if (t->catalog == NULL || t->system_area_data == NULL) {
            /* isohybrid makes only sense together with ISOLINUX boot image
               and externally provided System Area.
            */
            {ret = ISO_ISOLINUX_CANT_PATCH; goto ex;}
        }
        cylsize = t->partition_heads_per_cyl * t->partition_secs_per_head
                  * 512;
    } else if (always_align) {
        cylsize = t->partition_heads_per_cyl * t->partition_secs_per_head
                  * 512;
    } 
    if (cylsize == 0)
        {ret = ISO_SUCCESS; goto ex;}
    if (((double) imgsize) / (double) cylsize > 1024.0) {
        iso_msgs_submit(0,
                  "Image size exceeds 1024 cylinders. Cannot align partition.",
                  0, "WARNING", 0);
        iso_msgs_submit(0,
               "There are said to be BIOSes which will not boot this via MBR.",
               0, "WARNING", 0);
        {ret = ISO_SUCCESS; goto ex;}
    }

    frac = imgsize % cylsize;
    imgsize += (frac > 0 ? cylsize - frac : 0);

    frac = imgsize - ((off_t) img_blocks) * (off_t) 2048;
    if (frac == 0)
        {ret = ISO_SUCCESS; goto ex;}
    t->post_iso_part_pad = 0;
    if (frac % 2048) {
        t->post_iso_part_pad = 2048 - frac % 2048;
        sprintf(msg,
 "Cylinder aligned image size is not divisible by 2048. Have to add %d bytes.",
                t->post_iso_part_pad);
        iso_msgs_submit(0, msg, 0, "WARNING", 0);
    }

#ifdef Libisofs_part_align_writeR

    t->part_align_blocks = (frac + 2047) / 2048;

#else

    t->opts->tail_blocks += (frac + 2047) / 2048;

#endif /* ! Libisofs_part_align_writeR */

    ret = ISO_SUCCESS;
ex:;
    LIBISO_FREE_MEM(msg);
    return ret;
}


int iso_register_apm_entry(struct iso_apm_partition_request **req_array,
                           int *apm_req_count,
                           struct iso_apm_partition_request *req, int flag)
{
    struct iso_apm_partition_request *entry;

    if (*apm_req_count >= ISO_APM_ENTRIES_MAX)
        return ISO_BOOT_TOO_MANY_APM;
    entry = calloc(1, sizeof(struct iso_apm_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    
    memcpy(entry, req, sizeof(struct iso_apm_partition_request));
    if (req->image_path != NULL) {
        entry->image_path = strdup(req->image_path);
        if (entry->image_path == NULL) {
            LIBISO_FREE_MEM(entry);
            return ISO_OUT_OF_MEM;
        }
    }
    req_array[*apm_req_count] = entry;
    (*apm_req_count)++;
    return ISO_SUCCESS;
}


int iso_register_mbr_entry(struct iso_mbr_partition_request **req_array,
                           int *mbr_req_count,
                           struct iso_mbr_partition_request *req, int flag)
{
    struct iso_mbr_partition_request *entry;

    if (*mbr_req_count >= ISO_MBR_ENTRIES_MAX)
        return ISO_BOOT_TOO_MANY_MBR;
    entry = calloc(1, sizeof(struct iso_mbr_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    
    memcpy(entry, req, sizeof(struct iso_mbr_partition_request));
    if (req->image_path != NULL) {
        entry->image_path = strdup(req->image_path);
        if (entry->image_path == NULL) {
            LIBISO_FREE_MEM(entry);
            return ISO_OUT_OF_MEM;
        }
    }
    req_array[*mbr_req_count] = entry;
    (*mbr_req_count)++;
    return ISO_SUCCESS;
}

int iso_register_gpt_entry(struct iso_gpt_partition_request **req_array,
                           int *gpt_req_count,
                           struct iso_gpt_partition_request *req, int flag)
{
    struct iso_gpt_partition_request *entry;

    if (*gpt_req_count >= ISO_GPT_ENTRIES_MAX)
        return ISO_BOOT_TOO_MANY_GPT;
    entry = calloc(1, sizeof(struct iso_gpt_partition_request));
    if (entry == NULL)
        return ISO_OUT_OF_MEM;
    
    memcpy(entry, req, sizeof(struct iso_gpt_partition_request));
    if (req->image_path != NULL) {
        entry->image_path = strdup(req->image_path);
        if (entry->image_path == NULL) {
            LIBISO_FREE_MEM(entry);
            return ISO_OUT_OF_MEM;
        }
    }
    req_array[*gpt_req_count] = entry;
    (*gpt_req_count)++;
    return ISO_SUCCESS;
}

#ifdef Libisofs_with_uuid_generatE

static void swap_uuid(void *u_pt)
{
     uint8_t tr, *u;

     u = (uint8_t *) u_pt;
     tr = u[0]; u[0] = u[3]; u[3] = tr;
     tr = u[1]; u[1] = u[2]; u[2] = tr;
     tr = u[4]; u[4] = u[5]; u[5] = tr;
     tr = u[6]; u[6] = u[7]; u[7] = tr;
}

#endif /* Libisofs_with_uuid_generatE */


/* CRC-32 as of GPT and Ethernet.
   Parameters are deduced from a table driven implementation in isohybrid.c
*/
uint32_t iso_crc32_gpt(unsigned char *data, int count, int flag)
{   
    unsigned int acc, top, result = 0;
    long int i;

    /* Chosen so that the CRC of 0 bytes of input is 0x00000000 */
    acc = 0x46af6449;

    /* Process data bits and flush numerator by 32 zero bits */
    for (i = 0; i < count * 8 + 32; i++) {
        top = acc & 0x80000000;
        acc = (acc << 1);
        if (i < count * 8)
            /* The least significant bits of input bytes get processed first */
            acc |= ((data[i / 8] >> (i % 8)) & 1);
        if (top)
            /* Division by the generating polynomial */
            acc ^= 0x04c11db7;
    }
    /* Mirror residue bits */
    for (i = 0; i < 32; i++)
        if (acc & (1 << i))
            result |= 1 << (31 - i);
    /* Return bit complement */
    return result ^ 0xffffffff;
}

void iso_mark_guid_version_4(uint8_t *u)
{
    /* Mark as UUID version 4. RFC 4122 says u[6], but UEFI prescribes
       bytes 6 and 7 to be swapped.
    */
    u[7] = (u[7] & 0x0f) | 0x40;

    /* Variant is "1 0 x" as described in RFC 4122.
    */
    u[8] = (u[8] & 0x3f) | 0x80;

    return;
}

void iso_generate_gpt_guid(uint8_t guid[16])
{

#ifdef Libisofs_with_uuid_generatE

    uuid_t u;

    uuid_generate(u);
    swap_uuid((void *) u);
    memcpy(guid, u, 16);

#else

    uint8_t *u;
    /* produced by uuid_generate() and byte-swapped to UEFI specs */
    static uint8_t uuid_template[16] = {
        0xee, 0x29, 0x9d, 0xfc, 0x65, 0xcc, 0x7c, 0x40,
        0x92, 0x61, 0x5b, 0xcd, 0x6f, 0xed, 0x08, 0x34
    };
    uint32_t rnd, salt;
    struct timeval tv;
    pid_t pid;
    int i, ret, fd;

    u = guid;

    /* First try /dev/urandom
    */
    fd = open("/dev/urandom", O_RDONLY | O_BINARY);
    if (fd == -1)
        goto fallback;
    ret = read(fd, u, 16);
    if (ret != 16) {
        close(fd);
        goto fallback;
    }
    close(fd);
    iso_mark_guid_version_4(u);
    return;


fallback:;
    pid = getpid();
    salt = iso_crc32_gpt((unsigned char *) &guid, sizeof(uint8_t *), 0) ^ pid; 

    /* This relies on the uniqueness of the template and the rareness of
       bootable ISO image production via libisofs. Estimated 48 bits of
       entropy should influence the production of a single day. 
       So first collisions are to be expected with about 16 million images
       per day.
    */
    memcpy(u, uuid_template, 16);
    gettimeofday(&tv, NULL);
    for (i = 0; i < 4; i++)
        u[i] = (salt >> (8 * i)) & 0xff;
    for (i = 0; i < 2; i++)
        u[4 + i] = (pid >> (8 * i)) & 0xff;
    u[6] = ((salt >> 8) ^ (pid >> 16)) & 0xff;
    rnd = ((0xffffff & tv.tv_sec) << 8) |
          (((tv.tv_usec >> 16) ^ (salt & 0xf0)) & 0xff);
    for (i = 0; i < 4; i++)
        u[10 + i] ^= (rnd >> (8 * i)) & 0xff;
    u[14] ^= (tv.tv_usec >> 8) & 0xff;
    u[15] ^= tv.tv_usec & 0xff;

    iso_mark_guid_version_4(u);
    return;

#endif /* ! Libisofs_with_uuid_generatE */    

}

void iso_gpt_uuid(Ecma119Image *t, uint8_t uuid[16])
{
    if (t->gpt_uuid_counter == 0)
        iso_generate_gpt_guid(t->gpt_uuid_base);

    memcpy(uuid, t->gpt_uuid_base, 16);

    /* Previous implementation changed only byte 9. So i expand it by applying
       the counter in little-endian style.
    */
    uuid[9] ^= t->gpt_uuid_counter & 0xff;
    uuid[10] ^= (t->gpt_uuid_counter >> 8) & 0xff;
    uuid[11] ^= (t->gpt_uuid_counter >> 16) & 0xff;
    uuid[12] ^= (t->gpt_uuid_counter >> 24) & 0xff;
    t->gpt_uuid_counter++;
    return;
}

int assess_appended_gpt(Ecma119Image *t, int flag)
{
    static uint8_t basic_data_uuid[16] = {
        0xa2, 0xa0, 0xd0, 0xeb, 0xe5, 0xb9, 0x33, 0x44,
        0x87, 0xc0, 0x68, 0xb6, 0xb7, 0x26, 0x99, 0xc7
    };
    static uint8_t efi_sys_uuid[16] = {
       0x28, 0x73, 0x2a, 0xc1, 0x1f, 0xf8, 0xd2, 0x11,
       0xba, 0x4b, 0x00, 0xa0, 0xc9, 0x3e, 0xc9, 0x3b
    };
    static uint8_t hfs_plus_uuid[16] = {
        0x00, 0x53, 0x46, 0x48, 0x00, 0x00, 0xaa, 0x11,
        0xaa, 0x11, 0x00, 0x30, 0x65, 0x43, 0xec, 0xac
    };
    static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    int i, ret, do_apm = 0, do_gpt = 0, index, already_in_gpt = 0;
    int first_partition, last_partition;
    uint8_t gpt_name[72], *type_uuid;
    char apm_type[33];

#ifndef Libisofs_appended_partitions_inlinE
    if (!t->gpt_backup_outside)
        return 2;
#endif

    if ((t->apm_req_count > 0 && t->opts->part_like_isohybrid) ||
       (t->have_appended_partitions && t->opts->appended_as_apm))
       do_apm = 1;
    if (t->gpt_req_count > 0 ||
        (t->have_appended_partitions && t->opts->appended_as_gpt))
       do_gpt = 1;

    if (do_apm == 0 && do_gpt == 0)
            return 2;

    /* Represent appended partitions */
    iso_tell_max_part_range(t->opts, &first_partition, &last_partition, 0);
    for (i = first_partition - 1; i < last_partition; i++) {
        if (t->opts->appended_partitions[i] == NULL)
    continue;
        if (do_apm) {
            memset(gpt_name, 0, 32);
            sprintf((char *) gpt_name, "Appended%d", i + 1);
            strcpy(apm_type, "Data");
            if (t->opts->appended_part_gpt_flags[i] & 1) {
                if (memcmp(t->opts->appended_part_type_guids[i], hfs_plus_uuid,
                           16) == 0)
                    strcpy(apm_type, "Apple_HFS");
            }
            ret = iso_quick_apm_entry(t->apm_req, &(t->apm_req_count),
                            t->appended_part_start[i] * t->hfsp_iso_block_fac,
                            t->appended_part_size[i] * t->hfsp_iso_block_fac,
                            (char *) gpt_name, apm_type);
            if (ret < 0)
                return ret;
        }
        if (do_gpt)
            already_in_gpt = iso_find_gpt_entry(t->gpt_req, t->gpt_req_count,
                                    ((uint64_t) t->appended_part_start[i]) * 4,
                                    ((uint64_t) t->appended_part_size[i]) * 4,
                                    &index, 0);
        if (do_gpt && !already_in_gpt) {
            memset(gpt_name, 0, 72);
            sprintf((char *) gpt_name, "Appended%d", i + 1);
            iso_ascii_utf_16le(gpt_name);
            if (t->opts->appended_part_gpt_flags[i] & 1)
                type_uuid = t->opts->appended_part_type_guids[i];
            else if (t->opts->appended_part_types[i] == 0xef)
                type_uuid = efi_sys_uuid;
            else
                type_uuid = basic_data_uuid;
            ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                  ((uint64_t) t->appended_part_start[i]) * 4,
                                  ((uint64_t) t->appended_part_size[i]) * 4,
                                  type_uuid, zero_uuid,
                                  (uint64_t) 0, gpt_name);
            if (ret < 0)
                return ret;
            t->gpt_req[t->gpt_req_count - 1]->desired_slot = i + 1;
        } else if(do_gpt) {
            t->gpt_req[index]->desired_slot = i + 1;
        }
    }
    return ISO_SUCCESS;
}

/* Probably already called by tail_writer_compute_data_blocks via
   iso_align_isohybrid
*/
static int precompute_gpt(Ecma119Image *t)
{
    uint32_t gpt_part_start;
    int ret, sa_type;
    int gpt_count, gpt_idx[128], apm_count;

    /* Avoid repetition by  gpt_tail_writer_compute_data_blocks */
    t->gpt_is_computed = 1;


    /* Assess APM and GPT requests of isohybrid */
    sa_type = (t->system_area_options >> 2) & 0x3f;
    if (sa_type == 0 && (t->system_area_options & 3) == 2) {

        /* >>> ISOHYBRID :
               Shall isohybrid be combinable with other APM and GPT requesters ?
        */;
        /* <<< provisorily: Not compatible */
        ret = assess_isohybrid_gpt_apm(t, &gpt_count, gpt_idx, &apm_count, 0);
        if (ret < 0)
            return ret;
        if (t->gpt_req_count > 0 && gpt_count > 0)
            return ISO_BOOT_GPT_OVERLAP;
        if (t->apm_req_count > 0 && apm_count > 0)
            return ISO_BOOT_APM_OVERLAP;
        /* Register the GPT and APM partition entries */
        ret = assess_isohybrid_gpt_apm(t, &gpt_count, gpt_idx, &apm_count, 1);
        if (ret < 0)
            return ret;
    }

    /* With part_like_isohybrid:
       If no GPT is registered yet, and MBR, but neither CHRP nor ISOLINUX
       isohybrid is desired, then try to apply the isohybrid GPT and APM flags
       nevertheless. Avoid an overall ISO image GPT partition.
    */
    if (t->opts->part_like_isohybrid && t->gpt_req_count <= 0 &&
        ((t->system_area_options >> 2) & 0x3f) == 0 &&
        ((t->system_area_options >> 10) & 0xf) != 1 &&
        (!(t->system_area_options & 2))) {

        ret = assess_isohybrid_gpt_apm(t, &gpt_count, gpt_idx, &apm_count,
                                       1 | ((t->apm_req_count > 0) << 1) | 4);
        if (ret <= 0)
            return ret;
        t->apm_req_flags |= 2; /* Do not fill APM gaps,
                                  do not adjust final APM partition size */
    }

    /* Assess impact of appended partitions on GPT */
    ret = assess_appended_gpt(t, 0);
    if (ret < 0)
        return ret;

    /* Rectify APM requests early in order to learn the size of GPT.
       iso_write_apm() relies on this being already done here.
       So perform even if no GPT is required.
    */
    ret = rectify_apm(t);
    if (ret < 0)
        return ret;

#ifdef NIX
    /* Disabled */
    
    /* <<< ts B20526 : Dummy mock-up */
    if (t->gpt_req_count <= 0) { 

        /* <<< ??? Move to system_area.h and publish as macro ?
                   Or to make_isohybrid_mbr.c ?
        */
        static uint8_t hfs_uuid[16] = {
            0x00, 0x53, 0x46, 0x48, 0x00, 0x00, 0xaa, 0x11,
            0xaa, 0x11, 0x00, 0x30, 0x65, 0x43, 0xec, 0xac
        };
        static uint8_t basic_data_uuid[16] = {
            0xa2, 0xa0, 0xd0, 0xeb, 0xe5, 0xb9, 0x33, 0x44,
            0x87, 0xc0, 0x68, 0xb6, 0xb7, 0x26, 0x99, 0xc7
        };

        uint8_t gpt_name[72];
        static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        static uint64_t gpt_flags = (((uint64_t) 1) << 60) | 1;

        memset(gpt_name, 0, 72);
        gpt_name[0] = 'T'; gpt_name[2] = '1';
        strcpy((char *) gpt_name, "GPT Test 1");
        iso_ascii_utf_16le(gpt_name);
        /*
        ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                  (uint64_t) (16 * 4),  (uint64_t) (20 * 4),
                                  hfs_uuid, zero_uuid, gpt_flags, gpt_name);
        / * Caution: Size 90 causes intentional partition overlap error * /
        ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                  (uint64_t) (30 * 4), (uint64_t) (90 * 4),
                                  hfs_uuid, zero_uuid,
                                  gpt_flags, gpt_name);
        */ 
        ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                  (uint64_t) (30 * 4),  (uint64_t) (40 * 4), 
                                  hfs_uuid, zero_uuid,
                                  gpt_flags, gpt_name);
        if (ret < 0)
            return ret;
        strcpy((char *) gpt_name, "GPT Test 2");
        iso_ascii_utf_16le(gpt_name);
        ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count),
                                  (uint64_t) (110 * 4),  (uint64_t) (60 * 4), 
                                  basic_data_uuid, zero_uuid,
                                  gpt_flags, gpt_name);
        if (ret < 0)
            return ret;
    }
#endif /* NIX */

    /* Is a GPT requested ? */
    t->gpt_backup_end = 0;
    t->gpt_max_entries = 0;
    if (t->gpt_req_count == 0)
        return ISO_SUCCESS;

    /* Determine GPT partition start in System Area, */
    gpt_part_start = 0;
    if (t->apm_req_count > 0) {
        if (t->opts->apm_block_size == 0)
            t->opts->apm_block_size = 2048;
        gpt_part_start = (t->apm_req_count + 1) *
                         (t->opts->apm_block_size / 512);
    }
    if (gpt_part_start < 2)
        gpt_part_start = 2; 
    else if (gpt_part_start >= 64)
        return ISO_BOOT_TOO_MANY_GPT;
    t->gpt_part_start = gpt_part_start;

    /* Necessary number of 2K blocks */
    t->gpt_max_entries = (64 - t->gpt_part_start) * 4;
    t->gpt_backup_size = ((t->gpt_max_entries / 4 + 1) * 512 + 2047) / 2048;

    return ISO_SUCCESS;
}


int gpt_tail_writer_compute_data_blocks(IsoImageWriter *writer)
{
    Ecma119Image *t;
    int ret;

    if (writer == NULL)
        return ISO_ASSERT_FAILURE;
    t = writer->target;

    if (! t->gpt_is_computed) {
        ret = precompute_gpt(t);
        if (ret < 0)
            return ret;
    }

    if (t->gpt_backup_outside) {
        t->total_size += t->gpt_backup_size * 2048;
        /* The ISO block number after the backup GPT header */
        t->gpt_backup_end = t->total_size / BLOCK_SIZE + t->opts->ms_block;
    } else {
        t->curblock += t->gpt_backup_size;
        /* The ISO block number after the backup GPT header */
        t->gpt_backup_end = t->curblock;
    }

    return ISO_SUCCESS;
}


int gpt_tail_writer_write_vol_desc(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


static int gpt_tail_writer_write_data(IsoImageWriter *writer)
{
    Ecma119Image *t;
    uint8_t *head, *new_head, *entries;
    uint8_t *backup_buf = NULL;
    uint32_t crc, i;
    uint64_t part_start;
    int ret;

    t = writer->target;
    if (t->gpt_backup_end == 0 || t->gpt_max_entries == 0)
        return ISO_SUCCESS; /* No backup GPT area reserved by compute_data() */

    backup_buf = calloc(1, t->gpt_backup_size * 2048);
    if (backup_buf == NULL)
        return ISO_OUT_OF_MEM;
    memset(backup_buf, 0, t->gpt_backup_size * 2048);

    /* Check whether GPT header block came through */
    head = t->sys_area_as_written + 512;
    if (strncmp((char *) head, "EFI PART", 8) != 0) {
tampered_head:;
        /* Send error message but do not prevent further image production */
        iso_msgs_submit(0,
                 "GPT header block was altered before writing to System Area.",
                 0, "FAILURE", 0);
        goto write_zeros;
    }
    for (i = 92; i < 512; i++)
        if (head[i])
            goto tampered_head;

    /* Patch memorized header block */
    new_head = backup_buf + t->gpt_backup_size * 2048 - 512;
    memcpy(new_head, head, 512);
    /* Exchange "Location of this header" and "Location of header backup" */
    memcpy(new_head + 24, head + 32, 8);
    memcpy(new_head + 32, head + 24, 8);
    /* Point to the backup partition entries */
    part_start = ((uint64_t) t->gpt_backup_end) * 4
                 - 1 - t->gpt_max_entries / 4;
    iso_lsb(new_head + 72, part_start & 0xffffffff, 4);
    iso_lsb(new_head + 76, (part_start >> 32) & 0xffffffff, 4);

    /* Compute new header CRC */
    memset(new_head + 16, 0, 4);
    crc = iso_crc32_gpt((unsigned char *) new_head, 92, 0); 
    iso_lsb(new_head + 16, crc, 4);

    /* Copy GPT entries */
    entries = t->sys_area_as_written + t->gpt_part_start * 512;
    memcpy(new_head - t->gpt_max_entries * 128,
           entries, t->gpt_max_entries * 128);
              
    ret = iso_write(t, backup_buf, t->gpt_backup_size * 2048);
    free(backup_buf);
    if (ret < 0)
        return ret;

    if (!t->gpt_backup_outside) {

        /* >>> Why isn't t->curblock updated ? */;

    }
    return ISO_SUCCESS;

write_zeros:;
    ret = iso_write(t, backup_buf, t->gpt_backup_size * 2048);
    free(backup_buf);
    if (ret < 0)
        return ret;
    return ISO_SUCCESS;
}


static int gpt_tail_writer_free_data(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


int gpt_tail_writer_create(Ecma119Image *target)
{
    IsoImageWriter *writer;

    writer = calloc(1, sizeof(IsoImageWriter));
    if (writer == NULL) {
        return ISO_OUT_OF_MEM;
    }
    writer->compute_data_blocks = gpt_tail_writer_compute_data_blocks;
    writer->write_vol_desc = gpt_tail_writer_write_vol_desc;
    writer->write_data = gpt_tail_writer_write_data;
    writer->free_data = gpt_tail_writer_free_data;
    writer->data = NULL;
    writer->target = target;

    /* add this writer to image */
    target->writers[target->nwriters++] = writer;

    return ISO_SUCCESS;
}


/* ----------------------  Partition Prepend Writer --------------------- */


static int partprepend_writer_compute_data_blocks(IsoImageWriter *writer)
{
    Ecma119Image *t;
    IsoFileSrc *src;
    int ret, will_have_gpt = 0, with_chrp = 0, i, part_type, keep;
    static uint8_t zero_uuid[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    static uint64_t gpt_flags = (((uint64_t) 1) << 60) | 1;
    uint8_t gpt_name[72];
    uint64_t part_start;
    off_t start_byte, byte_count;

    /* <<< ??? Move to system_area.h and publish as macro ? */
    static uint8_t efi_sys_uuid[16] = {
       0x28, 0x73, 0x2a, 0xc1, 0x1f, 0xf8, 0xd2, 0x11,
       0xba, 0x4b, 0x00, 0xa0, 0xc9, 0x3e, 0xc9, 0x3b
    };

    if (writer == NULL)
        return ISO_ASSERT_FAILURE;
    t = writer->target;

    with_chrp = ((t->system_area_options & 0x3cff) == 0x0400);
    if (t->opts->efi_boot_partition != NULL ||
        t->gpt_req_count > 0) /* Might not catch all cases with GPT */
        will_have_gpt = 1;

    if (t->opts->efi_boot_partition != NULL) {
        keep = 0;
        if (t->efi_boot_part_filesrc != NULL) {
            /* A file in the emerging ISO image shall store its content
               as prepended partition.
               Install absolute block addresses and determine partition size.
            */
            src = t->efi_boot_part_filesrc;
            t->efi_boot_part_size = 0;
            for (i = 0; i < src->nsections; i++) {
                src->sections[i].block = t->curblock + t->efi_boot_part_size;
                t->efi_boot_part_size += (src->sections[i].size + 2047) / 2048;
            }
            part_start = t->curblock * 4;
        } else {
            ret = compute_partition_size(t, t->opts->efi_boot_partition,
                                         &(t->efi_boot_part_size),
                                         t->opts->efi_boot_part_flag & 1);
            if (ret < 0)
                return ret;
            part_start = t->curblock * 4;
            if (ret == ISO_SUCCESS + 1) {
                /* Interval from imported_iso in add-on session will be kept */
                ret = iso_interval_reader_start_size(t,
                                                  t->opts->efi_boot_partition,
                                                  &start_byte, &byte_count, 0);
                if (ret < 0)
                    return ret;
                part_start = start_byte / 512;
                keep = 1;
            }
        }
        memset(gpt_name, 0, 72);
        strcpy((char *) gpt_name, "EFI boot partition");
        iso_ascii_utf_16le(gpt_name);
        ret = iso_quick_gpt_entry(t->gpt_req, &(t->gpt_req_count), part_start,
                                 ((uint64_t) t->efi_boot_part_size) * 4,
                                 efi_sys_uuid, zero_uuid, gpt_flags, gpt_name);
        if (ret < 0)
            return ret;
        if (!keep)
            t->curblock += t->efi_boot_part_size;
    }

    if (with_chrp) {
        /* CHRP is not compatible with any other partition in MBR */
        if (t->opts->prep_partition != NULL || t->opts->fat || will_have_gpt ||
            t->mbr_req_count > 0)
            return ISO_BOOT_MBR_OVERLAP;
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count),
                                  (uint64_t) 0, (uint64_t) 0, 0x96, 0x80, 0);
        if (ret < 0)
            return ret;
        return ISO_SUCCESS;
    }

    part_start = t->curblock * 4;
    keep = 0;
    if (t->opts->prep_partition != NULL) {
        ret = compute_partition_size(t, t->opts->prep_partition,
                                     &(t->prep_part_size),
                                     t->opts->prep_part_flag & 1);
        if (ret < 0)
            return ret;
        if (ret == ISO_SUCCESS + 1) {
            /* Interval from imported_iso in add-on session will be kept */
            ret = iso_interval_reader_start_size(t,
                                                 t->opts->prep_partition,
                                                 &start_byte, &byte_count, 0);
            if (ret < 0)
                return ret;
            part_start = start_byte / 512;
            keep = 1;
        }
    }
    if (t->prep_part_size > 0 || t->opts->fat || will_have_gpt) {
        /* Protecting MBR entry for ISO start or whole ISO */
        part_type = 0xcd;
        if (t->opts->iso_mbr_part_type >= 0 &&
            t->opts->iso_mbr_part_type <= 255)
            part_type= t->opts->iso_mbr_part_type;
        if (will_have_gpt)
            part_type = 0xee;
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count),
                                  will_have_gpt ? (uint64_t) 1 :
                                  ((uint64_t) t->opts->partition_offset) * 4,
                                  (uint64_t) 0, part_type, 0, 0);
        if (ret < 0)
            return ret;
    }
    if (t->prep_part_size > 0) {
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count), part_start,
                                  ((uint64_t) t->prep_part_size) * 4,
                                  0x41, 0, 0);
        if (ret < 0)
            return ret;
        if (!keep) {
            t->curblock += t->prep_part_size;
            part_start = t->curblock * 4;
        } else {
            part_start += t->prep_part_size * 4;
        }
    } else {
        part_start = t->curblock * 4;
    }
    if (t->prep_part_size > 0 || t->opts->fat) {
        /* FAT partition or protecting MBR entry for ISO end */
        ret = iso_quick_mbr_entry(t->mbr_req, &(t->mbr_req_count),
                                  part_start, (uint64_t) 0,
                                  t->opts->fat ? 0x0c : 0xcd, 0, 0);
        if (ret < 0)
            return ret;
    }

    return ISO_SUCCESS;
}


static int partprepend_writer_write_vol_desc(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


static int partprepend_writer_write_data(IsoImageWriter *writer)
{
    Ecma119Image *t;
    int ret;

    t = writer->target;

    if (t->opts->efi_boot_partition != NULL && t->efi_boot_part_size) {

        if (t->efi_boot_part_filesrc != NULL) {
            ret = iso_filesrc_write_data(t, t->efi_boot_part_filesrc,
                                         NULL, NULL, 0);
        } else {
            ret = iso_write_partition_file(t, t->opts->efi_boot_partition,
                                       (uint32_t) 0, t->efi_boot_part_size,
                                       t->opts->efi_boot_part_flag & 1);
        }
        if (ret < 0)
            return ret;
    }
    if (t->opts->prep_partition != NULL && t->prep_part_size) {
        ret = iso_write_partition_file(t, t->opts->prep_partition,
                                       (uint32_t) 0, t->prep_part_size,
                                       t->opts->prep_part_flag & 1);
        if (ret < 0)
            return ret;
    }

    return ISO_SUCCESS;
}


static int partprepend_writer_free_data(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


int partprepend_writer_create(Ecma119Image *target)
{
    IsoImageWriter *writer;

    writer = calloc(1, sizeof(IsoImageWriter));
    if (writer == NULL) {
        return ISO_OUT_OF_MEM;
    }

    writer->compute_data_blocks = partprepend_writer_compute_data_blocks;
    writer->write_vol_desc = partprepend_writer_write_vol_desc;
    writer->write_data = partprepend_writer_write_data;
    writer->free_data = partprepend_writer_free_data;
    writer->data = NULL;
    writer->target = target;

    /* add this writer to image */
    target->writers[target->nwriters++] = writer;

    return ISO_SUCCESS;
}


#ifdef Libisofs_appended_partitions_inlinE

/* ----------------- Inline Partition Append Writer ------------------ */


static int partappend_writer_compute_data_blocks(IsoImageWriter *writer)
{
    int ret;

    ret = iso_compute_append_partitions(writer->target, 1);
    return ret;
}


static int partappend_writer_write_vol_desc(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


static int partappend_writer_write_data(IsoImageWriter *writer)
{
    Ecma119Image *target;
    int res, first_partition = 1, last_partition = 0;
    int i;

    target = writer->target;

    /* Append partition data */
    iso_tell_max_part_range(target->opts,
                            &first_partition, &last_partition, 0);
    
    for (i = first_partition - 1; i <= last_partition - 1; i++) {
        if (target->opts->appended_partitions[i] == NULL)
    continue;
        if (target->opts->appended_partitions[i][0] == 0)
    continue;
        res = iso_write_partition_file(target,
                                       target->opts->appended_partitions[i],
                                       target->appended_part_prepad[i],
                                       target->appended_part_size[i],
                                     target->opts->appended_part_flags[i] & 1);
        if (res < 0)
            return res;
        target->curblock += target->appended_part_size[i];
    }
    return ISO_SUCCESS;
}


static int partappend_writer_free_data(IsoImageWriter *writer)
{
    return ISO_SUCCESS;
}


int partappend_writer_create(Ecma119Image *target)
{
    IsoImageWriter *writer;

    writer = calloc(1, sizeof(IsoImageWriter));
    if (writer == NULL) {
        return ISO_OUT_OF_MEM;
    }

    writer->compute_data_blocks = partappend_writer_compute_data_blocks;
    writer->write_vol_desc = partappend_writer_write_vol_desc;
    writer->write_data = partappend_writer_write_data;
    writer->free_data = partappend_writer_free_data;
    writer->data = NULL;
    writer->target = target;

    /* add this writer to image */
    target->writers[target->nwriters++] = writer;

    return ISO_SUCCESS;
}

#endif /* Libisofs_appended_partitions_inlinE */


void iso_delete_gpt_apm_fillers(Ecma119Image *target, int flag)
{
    int i, widx;

    /* Dispose the requests with req_status bit0 */
    for (i = 0; i < target->gpt_req_count; i++) {
        if (target->gpt_req[i]->req_status & 1) {
            free(target->gpt_req[i]);
            target->gpt_req[i] = NULL;
        }
    }
    /* Densify the request arrays */
    widx = 0;
    for (i = 0; i < target->gpt_req_count; i++) {
        if (target->gpt_req[i] != NULL) {
            target->gpt_req[widx] = target->gpt_req[i];
            widx++;
        }
    }
    target->gpt_req_count = widx;

    /* And again for APM */
    for (i = 0; i < target->apm_req_count; i++) {
        if (target->apm_req[i]->req_status & 1) {
            free(target->apm_req[i]);
            target->apm_req[i] = NULL;
        }
    }
    widx = 0;
    for (i = 0; i < target->apm_req_count; i++) {
        if (target->apm_req[i] != NULL) {
            target->apm_req[widx] = target->apm_req[i];
            widx++;
        }
    }
    target->apm_req_count = widx;
}

