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Support for writing MBR in the system area, to make hybrid boot images.

With the specified isolinux option, a MBR is written to the system area, and this 
allows the image to boot from either CD/DVD or USB sticks.

This is also supported on overwriteable media (note that system area is always
overwritten), but it should not work on multisession media.
release-1.5.4.branch
Vreixo Formoso 14 years ago
parent
commit
7e97a45b20
  1. 2
      Makefile.am
  2. 21
      libisofs/ecma119.c
  3. 24
      libisofs/eltorito.h
  4. 59
      libisofs/system_area.c
  5. 48
      libisofs/system_area.h

2
Makefile.am

@ -52,6 +52,8 @@ libisofs_libisofs_la_SOURCES = \
libisofs/joliet.c \
libisofs/eltorito.h \
libisofs/eltorito.c \
libisofs/system_area.h \
libisofs/system_area.c \
libisofs/make_isohybrid_mbr.c \
libisofs/iso1999.h \
libisofs/iso1999.c \

21
libisofs/ecma119.c

@ -19,6 +19,7 @@
#include "messages.h"
#include "rockridge.h"
#include "util.h"
#include "system_area.h"
#include "libburn/libburn.h"
@ -784,10 +785,14 @@ void *write_function(void *arg)
target->bytes_written = (off_t) 0;
target->percent_written = 0;
/* Write System Area, 16 blocks of zeros (ECMA-119, 6.2.1) */
memset(buf, 0, BLOCK_SIZE);
for (i = 0; i < 16; ++i) {
res = iso_write(target, buf, BLOCK_SIZE);
/* Write System Area (ECMA-119, 6.2.1) */
{
uint8_t sa[16 * BLOCK_SIZE];
res = iso_write_system_area(target, sa);
if (res < 0) {
goto write_error;
}
res = iso_write(target, sa, 16 * BLOCK_SIZE);
if (res < 0) {
goto write_error;
}
@ -1054,6 +1059,14 @@ int ecma119_image_new(IsoImage *src, IsoWriteOpts *opts, Ecma119Image **img)
}
}
/* write the system area */
ret = iso_write_system_area(target, opts->overwrite);
if (ret < 0) {
iso_msg_debug(target->image->id,
"Error writing system area to overwrite buffer");
goto target_cleanup;
}
/* skip the first 16 blocks (system area) */
buf = opts->overwrite + 16 * BLOCK_SIZE;
voldesc_size *= BLOCK_SIZE;

24
libisofs/eltorito.h

@ -35,7 +35,12 @@ struct el_torito_boot_image {
IsoFile *image;
unsigned int bootable:1; /**< If the entry is bootable. */
unsigned int isolinux:1; /**< If the image will be patched */
/**
* isolinux options
* bit 0 -> whether to patch image
* bit 1 -> whether to create isolinux image
*/
unsigned int isolinux_options:2;
unsigned char type; /**< The type of image */
unsigned char partition_type; /**< type of partition for HD-emul images */
short load_seg; /**< Load segment for the initial boot image. */
@ -100,21 +105,4 @@ int el_torito_catalog_file_src_create(Ecma119Image *target, IsoFileSrc **src);
*/
int eltorito_writer_create(Ecma119Image *target);
/*
* 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);
#endif /* LIBISO_ELTORITO_H */

59
libisofs/system_area.c

@ -0,0 +1,59 @@
/*
* Copyright (c) 2008 Vreixo Formoso
*
* 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 as
* published by the Free Software Foundation. See COPYING file for details.
*/
#include "system_area.h"
#include "eltorito.h"
#include "filesrc.h"
#include <string.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);
int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
{
if ((t == NULL) || (buf == NULL)) {
return ISO_NULL_POINTER;
}
/* set buf to 0s */
memset(buf, 0, 16 * BLOCK_SIZE);
if (t->catalog != NULL && t->catalog->image->isolinux_options & 0x02) {
/* We need to write a MBR for an hybrid image */
int ret;
int img_blocks;
img_blocks = t->curblock;
ret = make_isohybrid_mbr(t->bootimg->sections[0].block, &img_blocks, (char*)buf, 0);
// FIXME the new img_blocks size should be taken into account
if (ret != 1) {
/* error, it should never happen */
return ISO_ASSERT_FAILURE;
}
}
return ISO_SUCCESS;
}

48
libisofs/system_area.h

@ -0,0 +1,48 @@
/*
* Copyright (c) 2008 Vreixo Formoso
*
* 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 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);
#endif /* SYSTEM_AREA_H_ */
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