From 6fc3bb677746fb97a855feb85bd4a9c7a8e098dd Mon Sep 17 00:00:00 2001
From: Thomas Schmitt <scdbackup@gmx.net>
Date: Tue, 12 Jun 2012 21:16:56 +0200
Subject: [PATCH] New ystem area sub type CHRP with
 iso_write_opts_set_system_area()

---
 doc/boot_sectors.txt   |  4 ++++
 libisofs/ecma119.c     |  7 ++++---
 libisofs/libisofs.h    | 14 +++++++++++---
 libisofs/system_area.c | 17 ++++++++++++++---
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/doc/boot_sectors.txt b/doc/boot_sectors.txt
index 9935dd0..8e336c2 100644
--- a/doc/boot_sectors.txt
+++ b/doc/boot_sectors.txt
@@ -1416,5 +1416,9 @@ Involved -as mkisofs options:
   -efi-boot-part DISKFILE
   -prep-boot-part DISKFILE
 
+
+>>> What boots by what ?
+
+
 ------------------------------------------------------------------------------
 
diff --git a/libisofs/ecma119.c b/libisofs/ecma119.c
index f1ab0e0..b33793f 100644
--- a/libisofs/ecma119.c
+++ b/libisofs/ecma119.c
@@ -3235,8 +3235,9 @@ int iso_write_opts_get_data_start(IsoWriteOpts *opts, uint32_t *data_start,
  *              ISOLINUX boot image (see iso_image_set_boot_image()) and
  *              only if not bit0 is set.
  *        bit2-7= System area type
- *              0= PC-BIOS DOS MBR
- *              1= MIPS Big Endian Volume Header
+ *        bit8-9= Only with System area type 0 = MBR
+ *                Cylinder alignment mode
+ *        bit10-13= System area sub type
  * @param flag     bit0 = invalidate any attached system area data
  *                        same as data == NULL
  *                 bit1 = keep data unaltered
@@ -3258,7 +3259,7 @@ int iso_write_opts_set_system_area(IsoWriteOpts *opts, char data[32768],
         memcpy(opts->system_area_data, data, 32768);
     }
     if (!(flag & 4))
-        opts->system_area_options = options & 0x3ff;
+        opts->system_area_options = options & 0x3fff;
     return ISO_SUCCESS;
 }
 
diff --git a/libisofs/libisofs.h b/libisofs/libisofs.h
index fc2c149..8a40603 100644
--- a/libisofs/libisofs.h
+++ b/libisofs/libisofs.h
@@ -2145,12 +2145,20 @@ int iso_write_opts_set_fifo_size(IsoWriteOpts *opts, size_t fifo_size);
  *                 to 8.
  *                 This will overwrite the first 512 bytes of the submitted
  *        bit8-9= Only with System area type 0 = MBR
- *                @since 1.0.4
- *                Cylinder alignment mode eventually pads the image to make it
- *                end at a cylinder boundary.
+ *              @since 1.0.4
+ *              Cylinder alignment mode eventually pads the image to make it
+ *              end at a cylinder boundary.
  *                0 = auto (align if bit1)
  *                1 = always align to cylinder boundary
  *                2 = never align to cylinder boundary
+ *        bit10-13= System area sub type
+ *              @since 1.2.4
+ *              With type 0 = MBR:
+ *                Gets overridden by bit0 and bit1.
+ *                0 = no particular sub type
+ *                1 = CHRP: A single MBR partition of type 0x96 covers the
+ *                          ISO image. Not compatible with any other feature
+ *                          which needs to have own MBR partition entries.
  * @param flag
  *        bit0 = invalidate any attached system area data. Same as data == NULL
  *               (This re-activates eventually loaded image System Area data.
diff --git a/libisofs/system_area.c b/libisofs/system_area.c
index 8193722..8c27565 100644
--- a/libisofs/system_area.c
+++ b/libisofs/system_area.c
@@ -2008,7 +2008,8 @@ static int partprepend_writer_compute_data_blocks(IsoImageWriter *writer)
         return ISO_ASSERT_FAILURE;
     t = writer->target;
 
-    /* >>> t->chrp_mark */;
+    if (t->efi_boot_partition != NULL || t->hfsplus || t->gpt_req_count > 0)
+        will_have_gpt = 1;
 
     if (t->efi_boot_partition != NULL) {
         ret = compute_partition_size(t->efi_boot_partition,
@@ -2025,8 +2026,18 @@ static int partprepend_writer_compute_data_blocks(IsoImageWriter *writer)
         t->curblock += t->efi_boot_part_size;
     }
 
-    if (t->efi_boot_partition != NULL || t->hfsplus)
-        will_have_gpt = 1;
+    if ((((t->system_area_options >> 10) & 0xf) == 1) &&
+       ((t->system_area_options >> 2) & 0x3f) == 0) {
+        /* CHRP is not compatible with any other partition in MBR */
+        if (t->prep_partition != NULL || t->fat || will_have_gpt ||
+            t->mbr_req_count > 0)
+            return ISO_BOOT_MBR_OVERLAP;
+        ret = iso_quick_mbr_entry(t, (uint32_t) 0, (uint32_t) 0, 0x96, 0);
+        if (ret < 0)
+            return ret;
+        return ISO_SUCCESS;
+    }
+
     if (t->prep_partition != NULL) {
         ret = compute_partition_size(t->prep_partition, &(t->prep_part_size),
                                      0);