[gparted] Recognise GRUB2 core.img (#766989)

[Curtis Gedak <gedakc src gnome org>]

commit 8ac3a0e4ad335171cc67c4b8bc37e0d344ccb199
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Fri Jun 3 20:34:09 2016 +0100

    Recognise GRUB2 core.img (#766989)
    
    Recognise GRUB2 core.img boot code written to a partition without a file
    system.  Such setups are possible/likely with GPT partitioned disks as
    there is a specific partition type reserved for it [1][2]:
        21686148-6449-6E6F-744E-656564454649  (BIOS Boot partition)
    
    [1] GUID Partition Table, Partition types
        https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
    
    [2] BIOS boot partition
        https://en.wikipedia.org/wiki/BIOS_boot_partition
    
    Bug 766989 - zfsonline support - need file system name support for ZFS
                 type codes

 include/Utils.h     |   13 +++++++------
 src/GParted_Core.cc |   32 ++++++++++++++++++++------------
 src/Utils.cc        |    2 ++
 3 files changed, 29 insertions(+), 18 deletions(-)
---
diff --git a/include/Utils.h b/include/Utils.h
index 2256788..e14a527 100644
--- a/include/Utils.h
+++ b/include/Utils.h
@@ -90,14 +90,15 @@ enum FILESYSTEM
 
        // Recognised signatures but otherwise unsupported file system types
        FS_BITLOCKER       = 25,
-       FS_LINUX_SWRAID    = 26,
-       FS_LINUX_SWSUSPEND = 27,
-       FS_REFS            = 28,
-       FS_ZFS             = 29,
+       FS_GRUB2_CORE_IMG  = 26,
+       FS_LINUX_SWRAID    = 27,
+       FS_LINUX_SWSUSPEND = 28,
+       FS_REFS            = 29,
+       FS_ZFS             = 30,
 
        // Partition space usage colours
-       FS_USED            = 30,
-       FS_UNUSED          = 31
+       FS_USED            = 31,
+       FS_UNUSED          = 32
 } ;
 
 enum SIZE_UNIT
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index 9768ab8..5b8c0a8 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -1548,19 +1548,27 @@ FILESYSTEM GParted_Core::detect_filesystem_internal( PedDevice * lp_device, PedP
                const char * sig2;
                FILESYSTEM   fstype;
        } signatures[] = {
-               //offset1, sig1          , offset2, sig2  , fstype
-               { 65536LL, "ReIsEr4"     ,     0LL, NULL  , FS_REISER4   },
-               {   512LL, "LABELONE"    ,   536LL, "LVM2", FS_LVM2_PV   },
-               {     0LL, "LUKS\xBA\xBE",     0LL, NULL  , FS_LUKS      },
-               { 65600LL, "_BHRfS_M"    ,     0LL, NULL  , FS_BTRFS     },
-               {     3LL, "-FVE-FS-"    ,     0LL, NULL  , FS_BITLOCKER },
-               {  1030LL, "\x34\x34"    ,     0LL, NULL  , FS_NILFS2    }
+               //offset1, sig1              , offset2, sig2  , fstype
+               { 65536LL, "ReIsEr4"         ,     0LL, NULL  , FS_REISER4        },
+               {   512LL, "LABELONE"        ,   536LL, "LVM2", FS_LVM2_PV        },
+               {     0LL, "LUKS\xBA\xBE"    ,     0LL, NULL  , FS_LUKS           },
+               { 65600LL, "_BHRfS_M"        ,     0LL, NULL  , FS_BTRFS          },
+               {     3LL, "-FVE-FS-"        ,     0LL, NULL  , FS_BITLOCKER      },
+               {  1030LL, "\x34\x34"        ,     0LL, NULL  , FS_NILFS2         },
+               {     0LL, "\x52\x56\xBE\x1B",     0LL, NULL  , FS_GRUB2_CORE_IMG },
+               {     0LL, "\x52\x56\xBE\x6F",     0LL, NULL  , FS_GRUB2_CORE_IMG },
+               {     0LL, "\x52\xE8\x28\x01",     0LL, NULL  , FS_GRUB2_CORE_IMG },
+               {     0LL, "\x52\xBF\xF4\x81",     0LL, NULL  , FS_GRUB2_CORE_IMG }
        };
-       // Reference:
-       //   Detecting BitLocker
-       //   http://blogs.msdn.com/b/si_team/archive/2006/10/26/detecting-bitlocker.aspx
-       // Consider validation of BIOS Parameter Block fields as unnecessary for
-       // simple recognition only of BitLocker.
+       // For simple BitLocker recognition consider validation of BIOS Parameter block
+       // fields unnecessary.
+       // *   Detecting BitLocker
+       //     http://blogs.msdn.com/b/si_team/archive/2006/10/26/detecting-bitlocker.aspx
+       //
+       // Recognise GRUB2 core.img just by any of the possible first 4 bytes of x86 CPU
+       // instructions it starts with.
+       // *   bootinfoscript v0.74 line 1963  [GRUB2 core.img possible staring 4 bytes]
+       //     
https://github.com/arvidjaar/bootinfoscript/blob/b1f711e39d7aa4021f4ad3d31468a8b1e1b3fda7/bootinfoscript#L1963
 
        for ( unsigned int i = 0 ; i < sizeof( signatures ) / sizeof( signatures[0] ) ; i ++ )
        {
diff --git a/src/Utils.cc b/src/Utils.cc
index 165c13b..8a8da5e 100644
--- a/src/Utils.cc
+++ b/src/Utils.cc
@@ -115,6 +115,7 @@ Glib::ustring Utils::get_color( FILESYSTEM filesystem )
                case FS_UNUSED          : return "#FFFFFF" ;    //white
                case FS_LVM2_PV         : return "#B39169" ;    //face skin dark
                case FS_BITLOCKER       : return "#494066" ;    //purple shadow
+               case FS_GRUB2_CORE_IMG  : return "#666666" ;    //~ dark gray
                case FS_LUKS            : return "#625B81" ;    //purple dark
                case FS_LINUX_SWRAID    : return "#5A4733" ;    // ~ dark brown
                case FS_LINUX_SWSUSPEND : return "#884631" ;    //red dark
@@ -291,6 +292,7 @@ Glib::ustring Utils::get_filesystem_string( FILESYSTEM filesystem )
                case FS_UNUSED          : return _("unused") ;
                case FS_LVM2_PV         : return "lvm2 pv" ;
                case FS_BITLOCKER       : return "bitlocker" ;
+               case FS_GRUB2_CORE_IMG  : return "grub2 core.img";
                case FS_LUKS            : return "luks";
                case FS_LINUX_SWRAID    : return "linux-raid" ;
                case FS_LINUX_SWSUSPEND : return "linux-suspend" ;