xref: /src/usr.sbin/makefs/cd9660/cd9660_eltorito.c

/*	$NetBSD: cd9660_eltorito.c,v 1.24 2020/11/15 00:18:48 jmcneill Exp $	*/

/*
 * Copyright (c) 2005 Daniel Watt, Walter Deignan, Ryan Gabrys, Alan
 * Perez-Rathke and Ram Vedam.  All rights reserved.
 *
 * This code was written by Daniel Watt, Walter Deignan, Ryan Gabrys,
 * Alan Perez-Rathke and Ram Vedam.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY DANIEL WATT, WALTER DEIGNAN, RYAN
 * GABRYS, ALAN PEREZ-RATHKE AND RAM VEDAM ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL DANIEL WATT, WALTER DEIGNAN, RYAN
 * GABRYS, ALAN PEREZ-RATHKE AND RAM VEDAM BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE,DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */


#include "cd9660.h"
#include "cd9660_eltorito.h"
#include <sys/bootblock.h>
#include <util.h>

#include <sys/cdefs.h>
#if defined(__RCSID) && !defined(__lint)
__RCSID("$NetBSD: cd9660_eltorito.c,v 1.24 2020/11/15 00:18:48 jmcneill Exp $");
#endif  /* !__lint */

#ifdef DEBUG
#define	ELTORITO_DPRINTF(__x)	printf __x
#else
#define	ELTORITO_DPRINTF(__x)
#endif

#include <util.h>

static struct boot_catalog_entry *cd9660_init_boot_catalog_entry(void);
static struct boot_catalog_entry *cd9660_boot_setup_validation_entry(char);
static struct boot_catalog_entry *cd9660_boot_setup_default_entry(
    struct cd9660_boot_image *);
static struct boot_catalog_entry *cd9660_boot_setup_section_head(char);
#if 0
static u_char cd9660_boot_get_system_type(struct cd9660_boot_image *);
#endif

static struct cd9660_boot_image *default_boot_image;

int
cd9660_add_boot_disk(iso9660_disk *diskStructure, const char *boot_info)
{
	struct stat stbuf;
	const char *mode_msg;
	char *temp;
	char *sysname;
	char *filename;
	struct cd9660_boot_image *new_image, *tmp_image;

	assert(boot_info != NULL);

	if (*boot_info == '\0') {
		warnx("Error: Boot disk information must be in the "
		      "format 'system;filename'");
		return 0;
	}

	/* First decode the boot information */
	temp = estrdup(boot_info);

	sysname = temp;
	filename = strchr(sysname, ';');
	if (filename == NULL) {
		warnx("supply boot disk information in the format "
		    "'system;filename'");
		free(temp);
		return 0;
	}

	*filename++ = '\0';

	if (diskStructure->verbose_level > 0) {
		printf("Found bootdisk with system %s, and filename %s\n",
		    sysname, filename);
	}
	new_image = ecalloc(1, sizeof(*new_image));
	new_image->loadSegment = 0;	/* default for now */

	/* Decode System */
	if (strcmp(sysname, "i386") == 0)
		new_image->system = ET_SYS_X86;
	else if (strcmp(sysname, "powerpc") == 0)
		new_image->system = ET_SYS_PPC;
	else if (strcmp(sysname, "macppc") == 0 ||
	         strcmp(sysname, "mac68k") == 0)
		new_image->system = ET_SYS_MAC;
	else if (strcmp(sysname, "efi") == 0)
		new_image->system = ET_SYS_EFI;
	else {
		warnx("boot disk system must be "
		      "i386, powerpc, macppc, mac68k, or efi");
		free(temp);
		free(new_image);
		return 0;
	}


	new_image->filename = estrdup(filename);

	free(temp);

	/* Get information about the file */
	if (lstat(new_image->filename, &stbuf) == -1)
		err(EXIT_FAILURE, "%s: lstat(\"%s\")", __func__,
		    new_image->filename);

	switch (stbuf.st_size) {
	case 1440 * 1024:
		new_image->targetMode = ET_MEDIA_144FDD;
		mode_msg = "Assigned boot image to 1.44 emulation mode";
		break;
	case 1200 * 1024:
		new_image->targetMode = ET_MEDIA_12FDD;
		mode_msg = "Assigned boot image to 1.2 emulation mode";
		break;
	case 2880 * 1024:
		new_image->targetMode = ET_MEDIA_288FDD;
		mode_msg = "Assigned boot image to 2.88 emulation mode";
		break;
	default:
		new_image->targetMode = ET_MEDIA_NOEM;
		mode_msg = "Assigned boot image to no emulation mode";
		break;
	}

	if (diskStructure->verbose_level > 0)
		printf("%s\n", mode_msg);

	new_image->size = stbuf.st_size;
	new_image->num_sectors =
	    howmany(new_image->size, diskStructure->sectorSize) *
	    howmany(diskStructure->sectorSize, 512);
	if (diskStructure->verbose_level > 0) {
		printf("New image has size %d, uses %d 512-byte sectors\n",
		    new_image->size, new_image->num_sectors);
	}
	new_image->sector = -1;
	/* Bootable by default */
	new_image->bootable = ET_BOOTABLE;
	/* Add boot disk */

	/* Group images for the same platform together. */
	TAILQ_FOREACH(tmp_image, &diskStructure->boot_images, image_list) {
		if (tmp_image->system != new_image->system)
			break;
	}

	if (tmp_image == NULL) {
		TAILQ_INSERT_HEAD(&diskStructure->boot_images, new_image,
		    image_list);
	} else
		TAILQ_INSERT_BEFORE(tmp_image, new_image, image_list);

	new_image->serialno = diskStructure->image_serialno++;

	new_image->platform_id = new_image->system;

	/* TODO : Need to do anything about the boot image in the tree? */
	diskStructure->is_bootable = 1;

	/* First boot image is initial/default entry. */
	if (default_boot_image == NULL)
		default_boot_image = new_image;

	return 1;
}

int
cd9660_eltorito_add_boot_option(iso9660_disk *diskStructure,
    const char *option_string, const char *value)
{
	char *eptr;
	struct cd9660_boot_image *image;

	assert(option_string != NULL);

	/* Find the last image added */
	TAILQ_FOREACH(image, &diskStructure->boot_images, image_list) {
		if (image->serialno + 1 == diskStructure->image_serialno)
			break;
	}
	if (image == NULL)
		errx(EXIT_FAILURE, "Attempted to add boot option, "
		    "but no boot images have been specified");

	if (strcmp(option_string, "no-emul-boot") == 0) {
		image->targetMode = ET_MEDIA_NOEM;
	} else if (strcmp(option_string, "no-boot") == 0) {
		image->bootable = ET_NOT_BOOTABLE;
	} else if (strcmp(option_string, "hard-disk-boot") == 0) {
		image->targetMode = ET_MEDIA_HDD;
	} else if (strcmp(option_string, "boot-load-segment") == 0) {
		image->loadSegment = strtoul(value, &eptr, 16);
		if (eptr == value || *eptr != '\0' || errno != ERANGE) {
			warn("%s: strtoul", __func__);
			return 0;
		}
	} else if (strcmp(option_string, "platformid") == 0) {
		if (strcmp(value, "efi") == 0)
			image->platform_id = ET_SYS_EFI;
		else {
			warn("%s: unknown platform: %s", __func__, value);
			return 0;
		}
	} else {
		return 0;
	}
	return 1;
}

static struct boot_catalog_entry *
cd9660_init_boot_catalog_entry(void)
{
	return ecalloc(1, sizeof(struct boot_catalog_entry));
}

static struct boot_catalog_entry *
cd9660_boot_setup_validation_entry(char sys)
{
	struct boot_catalog_entry *entry;
	boot_catalog_validation_entry *ve;
	int16_t checksum;
	unsigned char *csptr;
	size_t i;
	entry = cd9660_init_boot_catalog_entry();

	entry->entry_type = ET_ENTRY_VE;
	ve = &entry->entry_data.VE;

	ve->header_id[0] = 1;
	ve->platform_id[0] = sys;
	ve->key[0] = 0x55;
	ve->key[1] = 0xAA;

	/* Calculate checksum */
	checksum = 0;
	cd9660_721(0, ve->checksum);
	csptr = (unsigned char*)ve;
	for (i = 0; i < sizeof(*ve); i += 2) {
		checksum += (int16_t)csptr[i];
		checksum += 256 * (int16_t)csptr[i + 1];
	}
	checksum = -checksum;
	cd9660_721(checksum, ve->checksum);

        ELTORITO_DPRINTF(("%s: header_id %d, platform_id %d, key[0] %d, key[1] %d, "
	    "checksum %04x\n", __func__, ve->header_id[0], ve->platform_id[0],
	    ve->key[0], ve->key[1], checksum));
	return entry;
}

static struct boot_catalog_entry *
cd9660_boot_setup_default_entry(struct cd9660_boot_image *disk)
{
	struct boot_catalog_entry *default_entry;
	boot_catalog_initial_entry *ie;

	default_entry = cd9660_init_boot_catalog_entry();
	if (default_entry == NULL)
		return NULL;

	default_entry->entry_type = ET_ENTRY_IE;
	ie = &default_entry->entry_data.IE;

	ie->boot_indicator[0] = disk->bootable;
	ie->media_type[0] = disk->targetMode;
	cd9660_721(disk->loadSegment, ie->load_segment);
	ie->system_type[0] = disk->system;
	cd9660_721(disk->num_sectors, ie->sector_count);
	cd9660_731(disk->sector, ie->load_rba);

	ELTORITO_DPRINTF(("%s: boot indicator %d, media type %d, "
	    "load segment %04x, system type %d, sector count %d, "
	    "load rba %d\n", __func__, ie->boot_indicator[0],
	    ie->media_type[0], disk->loadSegment, ie->system_type[0],
	    disk->num_sectors, disk->sector));
	return default_entry;
}

static struct boot_catalog_entry *
cd9660_boot_setup_section_head(char platform)
{
	struct boot_catalog_entry *entry;
	boot_catalog_section_header *sh;

	entry = cd9660_init_boot_catalog_entry();
	if (entry == NULL)
		return NULL;

	entry->entry_type = ET_ENTRY_SH;
	sh = &entry->entry_data.SH;
	/* More by default. The last one will manually be set to 0x91 */
	sh->header_indicator[0] = ET_SECTION_HEADER_MORE;
	sh->platform_id[0] = platform;
	sh->num_section_entries[0] = 0;
	return entry;
}

static struct boot_catalog_entry *
cd9660_boot_setup_section_entry(struct cd9660_boot_image *disk)
{
	struct boot_catalog_entry *entry;
	boot_catalog_section_entry *se;
	if ((entry = cd9660_init_boot_catalog_entry()) == NULL)
		return NULL;

	entry->entry_type = ET_ENTRY_SE;
	se = &entry->entry_data.SE;

	se->boot_indicator[0] = ET_BOOTABLE;
	se->media_type[0] = disk->targetMode;
	cd9660_721(disk->loadSegment, se->load_segment);
	cd9660_721(disk->num_sectors, se->sector_count);
	cd9660_731(disk->sector, se->load_rba);
	return entry;
}

#if 0
static u_char
cd9660_boot_get_system_type(struct cd9660_boot_image *disk)
{
	/*
		For hard drive booting, we need to examine the MBR to figure
		out what the partition type is
	*/
	return 0;
}
#endif

/*
 * Set up the BVD, Boot catalog, and the boot entries, but do no writing
 */
int
cd9660_setup_boot(iso9660_disk *diskStructure, int first_sector)
{
	int sector;
	int used_sectors;
	int num_entries = 0;
	int catalog_sectors;
	struct boot_catalog_entry *x86_head, *mac_head, *ppc_head, *efi_head,
		*valid_entry, *default_entry, *temp, *head, **headp, *next;
	struct cd9660_boot_image *tmp_disk;
	u_char system;

	headp = NULL;
	x86_head = mac_head = ppc_head = efi_head = NULL;

	/* If there are no boot disks, don't bother building boot information */
	if (TAILQ_EMPTY(&diskStructure->boot_images))
		return 0;

	/* Point to catalog: For now assume it consumes one sector */
	ELTORITO_DPRINTF(("Boot catalog will go in sector %d\n", first_sector));
	diskStructure->boot_catalog_sector = first_sector;
	cd9660_bothendian_dword(first_sector,
		diskStructure->boot_descriptor->boot_catalog_pointer);

	/*
	 * Use system type of default image for validation entry. Fallback to
	 * X86 system type if not found.
	 */
	system = default_boot_image != NULL ? default_boot_image->system :
					      ET_SYS_X86;

	/* Step 1: Generate boot catalog */
	/* Step 1a: Validation entry */
	valid_entry = cd9660_boot_setup_validation_entry(system);
	if (valid_entry == NULL)
		return -1;

	/*
	 * Count how many boot images there are,
	 * and how many sectors they consume.
	 */
	num_entries = 1;
	used_sectors = 0;

	TAILQ_FOREACH(tmp_disk, &diskStructure->boot_images, image_list) {
		used_sectors += tmp_disk->num_sectors;

		/* One default entry per image */
		num_entries++;
	}
	catalog_sectors = howmany(num_entries * 0x20, diskStructure->sectorSize);
	used_sectors += catalog_sectors;

	if (diskStructure->verbose_level > 0) {
		printf("%s: there will be %i entries consuming %i sectors. "
		       "Catalog is %i sectors\n", __func__, num_entries,
		       used_sectors, catalog_sectors);
	}

	/* Populate sector numbers */
	sector = first_sector + catalog_sectors;
	TAILQ_FOREACH(tmp_disk, &diskStructure->boot_images, image_list) {
		tmp_disk->sector = sector;
		sector += tmp_disk->num_sectors /
		    (diskStructure->sectorSize / 512);
	}

	LIST_INSERT_HEAD(&diskStructure->boot_entries, valid_entry, ll_struct);

	/* Step 1b: Initial/default entry */
	/* TODO : PARAM */
	if (default_boot_image != NULL) {
		struct cd9660_boot_image *tcbi;
		TAILQ_FOREACH(tcbi, &diskStructure->boot_images, image_list) {
			if (tcbi == default_boot_image) {
				tmp_disk = tcbi;
				break;
			}
		}
	}
	if (tmp_disk == NULL)
		tmp_disk = TAILQ_FIRST(&diskStructure->boot_images);
	default_entry = cd9660_boot_setup_default_entry(tmp_disk);
	if (default_entry == NULL) {
		warnx("Error: memory allocation failed in cd9660_setup_boot");
		return -1;
	}

	LIST_INSERT_AFTER(valid_entry, default_entry, ll_struct);

	/* Todo: multiple default entries? */

	tmp_disk = TAILQ_FIRST(&diskStructure->boot_images);

	head = NULL;
	temp = default_entry;

	/* If multiple boot images are given : */
	for (; tmp_disk != NULL; tmp_disk = TAILQ_NEXT(tmp_disk, image_list)) {
		if (tmp_disk == default_boot_image)
			continue;

		/* Step 2: Section header */
		switch (tmp_disk->platform_id) {
		case ET_SYS_X86:
			headp = &x86_head;
			break;
		case ET_SYS_PPC:
			headp = &ppc_head;
			break;
		case ET_SYS_MAC:
			headp = &mac_head;
			break;
		case ET_SYS_EFI:
			headp = &efi_head;
			break;
		default:
			warnx("%s: internal error: unknown system type",
			    __func__);
			return -1;
		}

		if (*headp == NULL) {
			head =
			  cd9660_boot_setup_section_head(tmp_disk->platform_id);
			if (head == NULL) {
				warnx("Error: memory allocation failed in "
				      "cd9660_setup_boot");
				return -1;
			}
			LIST_INSERT_AFTER(default_entry, head, ll_struct);
			*headp = head;
		} else
			head = *headp;

		head->entry_data.SH.num_section_entries[0]++;

		/* Step 2a: Section entry and extensions */
		temp = cd9660_boot_setup_section_entry(tmp_disk);
		if (temp == NULL) {
			warn("%s: cd9660_boot_setup_section_entry", __func__);
			return -1;
		}

		while ((next = LIST_NEXT(head, ll_struct)) != NULL &&
		       next->entry_type == ET_ENTRY_SE)
			head = next;

		LIST_INSERT_AFTER(head, temp, ll_struct);
	}

	/* Find the last Section Header entry and mark it as the last. */
	head = NULL;
	LIST_FOREACH(next, &diskStructure->boot_entries, ll_struct) {
		if (next->entry_type == ET_ENTRY_SH)
			head = next;
	}
	if (head != NULL)
		head->entry_data.SH.header_indicator[0] = ET_SECTION_HEADER_LAST;

	/* TODO: Remaining boot disks when implemented */

	return first_sector + used_sectors;
}

int
cd9660_setup_boot_volume_descriptor(iso9660_disk *diskStructure,
    volume_descriptor *bvd)
{
	boot_volume_descriptor *bvdData =
	    (boot_volume_descriptor*)bvd->volumeDescriptorData;

	bvdData->boot_record_indicator[0] = ISO_VOLUME_DESCRIPTOR_BOOT;
	memcpy(bvdData->identifier, ISO_VOLUME_DESCRIPTOR_STANDARD_ID, 5);
	bvdData->version[0] = 1;
	memcpy(bvdData->boot_system_identifier, ET_ID, 23);
	memcpy(bvdData->identifier, ISO_VOLUME_DESCRIPTOR_STANDARD_ID, 5);
	diskStructure->boot_descriptor =
	    (boot_volume_descriptor*) bvd->volumeDescriptorData;
	return 1;
}

static int
cd9660_write_mbr_partition_entry(FILE *fd, int idx, off_t sector_start,
    off_t nsectors, int type)
{
	uint8_t val;
	uint32_t lba;

	if (fseeko(fd, (off_t)(idx) * 16 + 0x1be, SEEK_SET) == -1)
		err(1, "fseeko");

	val = 0x80; /* Bootable */
	fwrite(&val, sizeof(val), 1, fd);

	val = 0xff; /* CHS begin */
	fwrite(&val, sizeof(val), 1, fd);
	fwrite(&val, sizeof(val), 1, fd);
	fwrite(&val, sizeof(val), 1, fd);

	val = type; /* Part type */
	fwrite(&val, sizeof(val), 1, fd);

	val = 0xff; /* CHS end */
	fwrite(&val, sizeof(val), 1, fd);
	fwrite(&val, sizeof(val), 1, fd);
	fwrite(&val, sizeof(val), 1, fd);

	/* LBA extent */
	lba = htole32(sector_start);
	fwrite(&lba, sizeof(lba), 1, fd);
	lba = htole32(nsectors);
	fwrite(&lba, sizeof(lba), 1, fd);

	return 0;
}

static int
cd9660_write_apm_partition_entry(FILE *fd, int idx, int total_partitions,
    off_t sector_start, off_t nsectors, off_t sector_size,
    const char *part_name, const char *part_type)
{
	uint32_t apm32, part_status;
	uint16_t apm16;

	/* See Apple Tech Note 1189 for the details about the pmPartStatus
	 * flags.
	 * Below the flags which are default:
	 * - IsValid     0x01
	 * - IsAllocated 0x02
	 * - IsReadable  0x10
	 * - IsWritable  0x20
	 */
	part_status = APPLE_PS_VALID | APPLE_PS_ALLOCATED | APPLE_PS_READABLE |
	    APPLE_PS_WRITABLE;

	if (fseeko(fd, (off_t)(idx + 1) * sector_size, SEEK_SET) == -1)
		err(1, "fseeko");

	/* Signature */
	apm16 = htobe16(0x504d);
	fwrite(&apm16, sizeof(apm16), 1, fd);
	apm16 = 0;
	fwrite(&apm16, sizeof(apm16), 1, fd);

	/* Total number of partitions */
	apm32 = htobe32(total_partitions);
	fwrite(&apm32, sizeof(apm32), 1, fd);
	/* Bounds */
	apm32 = htobe32(sector_start);
	fwrite(&apm32, sizeof(apm32), 1, fd);
	apm32 = htobe32(nsectors);
	fwrite(&apm32, sizeof(apm32), 1, fd);

	fwrite(part_name, strlen(part_name) + 1, 1, fd);
	fseek(fd, 32 - strlen(part_name) - 1, SEEK_CUR);
	fwrite(part_type, strlen(part_type) + 1, 1, fd);
	fseek(fd, 32 - strlen(part_type) - 1, SEEK_CUR);

	apm32 = 0;
	/* pmLgDataStart */
	fwrite(&apm32, sizeof(apm32), 1, fd);
	/* pmDataCnt */
	apm32 = htobe32(nsectors);
	fwrite(&apm32, sizeof(apm32), 1, fd);
	/* pmPartStatus */
	apm32 = htobe32(part_status);
	fwrite(&apm32, sizeof(apm32), 1, fd);

	return 0;
}

int
cd9660_write_boot(iso9660_disk *diskStructure, FILE *fd)
{
	struct boot_catalog_entry *e;
	struct cd9660_boot_image *t;
	int apm_partitions = 0;
	int mbr_partitions = 0;

	/* write boot catalog */
	if (fseeko(fd, (off_t)diskStructure->boot_catalog_sector *
	    diskStructure->sectorSize, SEEK_SET) == -1)
		err(1, "fseeko");

	if (diskStructure->verbose_level > 0) {
		printf("Writing boot catalog to sector %" PRId64 "\n",
		    diskStructure->boot_catalog_sector);
	}
	LIST_FOREACH(e, &diskStructure->boot_entries, ll_struct) {
		if (diskStructure->verbose_level > 0) {
			printf("Writing catalog entry of type %d\n",
			    e->entry_type);
		}
		/*
		 * It doesnt matter which one gets written
		 * since they are the same size
		 */
		fwrite(&(e->entry_data.VE), 1, 32, fd);
	}
	if (diskStructure->verbose_level > 0)
		printf("Finished writing boot catalog\n");

	/* copy boot images */
	TAILQ_FOREACH(t, &diskStructure->boot_images, image_list) {
		if (diskStructure->verbose_level > 0) {
			printf("Writing boot image from %s to sectors %d\n",
			    t->filename, t->sector);
		}
		cd9660_copy_file(diskStructure, fd, t->sector, t->filename);

		if (t->system == ET_SYS_MAC)
			apm_partitions++;
		if (t->system == ET_SYS_PPC)
			mbr_partitions++;
	}

	/* some systems need partition tables as well */
	if (mbr_partitions > 0 || diskStructure->chrp_boot) {
		uint16_t sig;

		fseek(fd, 0x1fe, SEEK_SET);
		sig = htole16(0xaa55);
		fwrite(&sig, sizeof(sig), 1, fd);

		mbr_partitions = 0;

		/* Write ISO9660 descriptor, enclosing the whole disk */
		if (diskStructure->chrp_boot)
			cd9660_write_mbr_partition_entry(fd, mbr_partitions++,
			    0, diskStructure->totalSectors *
			    (diskStructure->sectorSize / 512), 0x96);

		/* Write all partition entries */
		TAILQ_FOREACH(t, &diskStructure->boot_images, image_list) {
			if (t->system != ET_SYS_PPC)
				continue;
			cd9660_write_mbr_partition_entry(fd, mbr_partitions++,
			    t->sector * (diskStructure->sectorSize / 512),
			    t->num_sectors * (diskStructure->sectorSize / 512),
			    0x41 /* PReP Boot */);
		}
	}

	if (apm_partitions > 0) {
		/* Write DDR and global APM info */
		uint32_t apm32;
		uint16_t apm16;
		int total_parts;

		fseek(fd, 0, SEEK_SET);
		apm16 = htobe16(0x4552);
		fwrite(&apm16, sizeof(apm16), 1, fd);
		/* Device block size */
		apm16 = htobe16(512);
		fwrite(&apm16, sizeof(apm16), 1, fd);
		/* Device block count */
		apm32 = htobe32(diskStructure->totalSectors *
		    (diskStructure->sectorSize / 512));
		fwrite(&apm32, sizeof(apm32), 1, fd);
		/* Device type/id */
		apm16 = htobe16(1);
		fwrite(&apm16, sizeof(apm16), 1, fd);
		fwrite(&apm16, sizeof(apm16), 1, fd);

		/* Count total needed entries */
		total_parts = 2 + apm_partitions; /* Self + ISO9660 */

		/* Write self-descriptor */
		cd9660_write_apm_partition_entry(fd, 0, total_parts, 1,
		    total_parts, 512, "Apple", "Apple_partition_map");

		/* Write all partition entries */
		apm_partitions = 0;
		TAILQ_FOREACH(t, &diskStructure->boot_images, image_list) {
			if (t->system != ET_SYS_MAC)
				continue;

			cd9660_write_apm_partition_entry(fd,
			    1 + apm_partitions++, total_parts,
			    t->sector * (diskStructure->sectorSize / 512),
			    t->num_sectors * (diskStructure->sectorSize / 512),
			    512, "CD Boot", "Apple_Bootstrap");
		}

		/* Write ISO9660 descriptor, enclosing the whole disk */
		cd9660_write_apm_partition_entry(fd, 2 + apm_partitions,
		    total_parts, 0, diskStructure->totalSectors *
		    (diskStructure->sectorSize / 512), 512, "ISO9660",
		    "CD_ROM_Mode_1");
	}

	return 0;
}