From b83ff630d169837d5d4963ef320f653bfbc6ae0e Mon Sep 17 00:00:00 2001
From: Thomas Schmitt <scdbackup@gmx.net>
Date: Tue, 16 Apr 2013 12:44:16 +0000
Subject: [PATCH] Recognizing grub2_mbr= on image load

---
 xorriso/iso_img.c           | 75 +++++++++++++++++++++++++++++++++----
 xorriso/xorriso_timestamp.h |  2 +-
 2 files changed, 68 insertions(+), 9 deletions(-)

diff --git a/xorriso/iso_img.c b/xorriso/iso_img.c
index 23f510cf..5a0c3c19 100644
--- a/xorriso/iso_img.c
+++ b/xorriso/iso_img.c
@@ -211,6 +211,40 @@ int Xorriso_is_isohybrid(struct XorrisO *xorriso, IsoFile *bootimg_node,
 }
 
 
+/* @return <0 yes , 0 no , <0 error */
+int Xorriso_is_grub2_elto(struct XorrisO *xorriso, IsoFile *bootimg_node,
+                          int flag)
+{
+#define Xorriso_grub2_boot_info_poS 2548
+ int ret, i;
+ unsigned char buf[Xorriso_grub2_boot_info_poS + 8];
+ void *data_stream= NULL;
+ off_t blk;
+
+ ret= Xorriso_iso_file_open(xorriso, "", (void *) bootimg_node,
+                            &data_stream, 1);
+ if(ret <= 0)
+   return(-1);
+ ret= Xorriso_iso_file_read(xorriso, data_stream, (char *) buf,
+                            Xorriso_grub2_boot_info_poS  + 8, 0);
+ Xorriso_iso_file_close(xorriso, &data_stream, 0);
+ if(ret < Xorriso_grub2_boot_info_poS + 8)
+   return(0);
+
+ /* >>> ??? Check for some id */;
+
+ /* Check whether it has grub2_boot_info patching */
+ blk= 0;
+ for(i= 0; i < 8; i++)
+   blk|= buf[Xorriso_grub2_boot_info_poS + i] << (8 * i);
+ blk-= 5;
+ blk/= 4;
+ if(blk != (off_t) xorriso->loaded_boot_bin_lba)
+   return(0);
+ return(1);
+}
+
+
 int Xorriso_image_has_md5(struct XorrisO *xorriso, int flag)
 {
  int ret;
@@ -730,9 +764,10 @@ int Xorriso__append_boot_params(char *line, ElToritoBootImage *bootimg,
 */
 int Xorriso_show_boot_info(struct XorrisO *xorriso, int flag)
 {
- int ret, bin_path_valid= 0,has_isolinux_mbr= 0, i, num_boots;
+ int ret, bin_path_valid= 0,has_isolinux_mbr= 0, i, num_boots, has_mbr= 0;
+ int has_grub2_mbr= 0;
  unsigned int mbr_lba= 0;
- off_t lb0_count;
+ off_t lb0_count, blk;
  char *respt, *path;
  unsigned char *lb0= NULL;
  struct burn_drive_info *dinfo;
@@ -785,18 +820,19 @@ no_boot:;
      bin_path_valid= 1;
  }
  sprintf(respt, "Boot record  : El Torito");
+ /* Load and examine potential MBR */
+ ret= burn_read_data(drive, (off_t) 0, (char *) lb0, (off_t) 2048,
+                     &lb0_count, 2);
+ if(ret > 0)
+   if(lb0[510] == 0x55 && lb0[511] == 0xaa)
+     has_mbr= 1;
  if(bin_path_valid)
    ret= Xorriso_is_isohybrid(xorriso, bootimg_node, 0);
  else
    ret= 0;
  if(ret > 0) {
-   /* Load and examine potential MBR */
-   ret= burn_read_data(drive, (off_t) 0, (char *) lb0, (off_t) 2048,
-                       &lb0_count, 2);
-   if(ret > 0) {
+   if(has_mbr) {
      has_isolinux_mbr= 1;
-     if(lb0[510] != 0x55 || lb0[511] != 0xaa)
-       has_isolinux_mbr= 0;
      mbr_lba= lb0[432] | (lb0[433] << 8) | (lb0[434] << 16) | (lb0[435] << 24);
      mbr_lba/= 4;
      if(mbr_lba != (unsigned int) xorriso->loaded_boot_bin_lba)
@@ -814,6 +850,29 @@ no_boot:;
    else
      strcat(respt, " , ISOLINUX boot image capable of isohybrid");
  }
+ if(bin_path_valid)
+   ret= Xorriso_is_grub2_elto(xorriso, bootimg_node, 0);
+ else
+   ret= 0;
+ if(ret > 0) {
+   if(has_mbr) {
+     has_grub2_mbr= 1;
+     blk= 0;
+     for(i= 0; i < 8; i++)
+       blk|= lb0[i + 0x1b0] << (8 * i);
+     blk-= 4;
+     blk/= 4;
+     if(blk != (off_t) xorriso->loaded_boot_bin_lba)
+       has_grub2_mbr= 0;
+     for(i= 32; i < 427; i++)
+       if(strncmp((char *) (lb0 + i), "GRUB", 4) == 0)
+     break;
+     if(i >= 427)
+       has_grub2_mbr= 0;
+   }
+   if(has_grub2_mbr)
+     strcat(respt, " , GRUB2 MBR pointing to first boot image");
+ }
  strcat(respt, "\n");
  Xorriso_toc_line(xorriso, flag & 8);
  if(flag & 2)
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index 3d132407..ca0c44aa 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2013.04.14.174902"
+#define Xorriso_timestamP "2013.04.16.124331"