libisofs/libisofs/system_area.h

/*
 * Copyright (c) 2008 Vreixo Formoso
 * Copyright (c) 2012 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.
 */

/*
 * Functions for dealing with the system area, this is, the first 16 blocks
 * of the image.
 *
 * At this time, this is only used for hybrid boot images with isolinux.
 */

#ifndef SYSTEM_AREA_H_
#define SYSTEM_AREA_H_

#include "ecma119.h"

/*
 * Create a MBR for an isohybrid enabled ISOLINUX boot image.
 *
 * It is assumed that the caller has verified the readiness of the boot image
 * by checking for 0xfb 0xc0 0x78 0x70 at bytes 0x40 to 0x43 of isolinux.bin.
 *
 * @param bin_lba    The predicted LBA of isolinux.bin within the emerging ISO.
 * @param img_blocks The predicted number of 2048 byte blocks in the ISO.
 *                   It will get rounded up to full MBs and that many blocks
 *                   must really be written as ISO 9660 image.
 * @param mbr        A buffer of at least 512 bytes to take the result which is
 *                   to be written as the very beginning of the ISO.
 * @param flag    unused yet, submit 0
 * @return  <0 = fatal, 0 = failed , 1 = ok , 2 = ok with size warning
 */
int make_isohybrid_mbr(int bin_lba, int *img_blocks, char *mbr, int flag);

/**
 * Write the system area for the given image to the given buffer.
 *
 * @param buf
 *      A buffer with at least 32 K allocated
 * @return
 *      1 if success, < 0 on error
 */
int iso_write_system_area(Ecma119Image *t, uint8_t *buf);

/**
 * Adjust t->tail_blocks to the eventual alignment needs of isohybrid booting.
 */
int iso_align_isohybrid(Ecma119Image *t, int flag);


/** 
 * Read the necessary ELF information from the first MIPS boot file.
 * See doc/boot_sectors.txt "DEC Boot Block" for "MIPS Little Endian".
 */
int iso_read_mipsel_elf(Ecma119Image *t, int flag);


/* Compute size and position of appended partitions.
*/
int iso_compute_append_partitions(Ecma119Image *t, int flag);


/* The parameter struct for production of a single Apple Partition Map entry.
   See also the partial APM description in doc/boot_sectors.txt.
   The list of entries is stored in Ecma119Image.apm_req.
   The size of a block can be chosen by setting Ecma119Image.apm_block_size.
   If an entry has start_block <=1, then its block_count will be adjusted
   to the final size of the partition map.
   If no such entry is requested, then it will be prepended automatically
   with name "Apple" and type "Apple_partition_map".
*/
struct iso_apm_partition_request {

    /* Always given in blocks of 2 KiB.
       Written to the ISO image according to Ecma119Image.apm_block_size.
    */
    uint32_t start_block;
    uint32_t block_count;

    /* All 32 bytes get copied to the system area.
       Take care to pad up short strings by 0.
    */
    uint8_t name[32];
    uint8_t type[32];
};

/* Copies the content of req and registers it in t.apm_req[].
   I.e. after the call the submitted storage of req can be disposed or re-used.
   Submit 0 as value flag.
*/
int iso_register_apm_entry(Ecma119Image *t,
                           struct iso_apm_partition_request *req, int flag);

/* Convenience frontend for iso_register_apm_entry().
   name and type are 0-terminated strings, which may get silently truncated.
*/
int iso_quick_apm_entry(Ecma119Image *t, 
           uint32_t start_block, uint32_t block_count, char *name, char *type);


#endif /* SYSTEM_AREA_H_ */