[gparted] Reorder crypt-luks detection (#741430)

[Curtis Gedak <gedakc src gnome org>]

commit bd9c76f602e0ef4eafe96cfe04818c33ecb3d13e
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Tue Dec 23 14:29:29 2014 +0000

    Reorder crypt-luks detection (#741430)
    
    (1) Add recognition of LUKS signatures detected by blkid command, via
    the FS_Info cache.
    
    (2) Relocate internal GParted detection of LUKS signature to back after
    libparted and blkid identification.  This reverses previous commit:
    
        7695593d21a51422c230001083858e738b94c5e5
        Improve crypt-luks detection (#578300)
    
    Bug 578300 must have been caused by either: (1) reading stale data from
    the whole disk device, or (2) formatting as LUKS over the top of ext3
    leaving old signatures behind.  Case (1) has been resolved by commit:
    
        3bea067596e3e2d6513cda2a66df1b3e4fa432fb
        Flush devices when scanning to prevent reading stale signatures
        (#723842)
    
    Re-tested case (2) and find that no old signatures are left behind:
    
        # mkfs.ext3 /dev/sda8
        # wipefs /dev/sda8
        offset               type
        ----------------------------------------------------------------
        0x438                ext3   [filesystem]
                             UUID:  756dcd5f-73c5-4881-81ee-dc88e8b18f42
        # cryptsetup luksFormat /dev/sda8
        # wipefs /dev/sda8
        offset               type
        ----------------------------------------------------------------
        0x0                  crypto_LUKS   [crypto]
                             UUID:  de15ed1a-f461-46b7-803b-d0fd3b4bd680
    
    Bug 741430 - GParted cannot recognise LVM signature on unpartitioned
                 drive

 src/GParted_Core.cc |   49 ++++++++++++++++++++++++-------------------------
 1 files changed, 24 insertions(+), 25 deletions(-)
---
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index 816a9cc..650960c 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -1250,32 +1250,9 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
 {
        char magic1[16] = "";
        char magic2[16] = "";
-
-       //Check for LUKS encryption prior to libparted file system detection.
-       //  Otherwise encrypted file systems such as ext3 will be detected by
-       //  libparted as 'ext3'.
-
-       //LUKS encryption
-       char * buf = static_cast<char *>( malloc( lp_device ->sector_size ) ) ;
-       if ( buf )
-       {
-               ped_device_open( lp_device );
-               ped_geometry_read( & lp_partition ->geom, buf, 0, 1 ) ;
-               memcpy(magic1, buf+0, 6) ;  //set binary magic data
-               ped_device_close( lp_device );
-               free( buf ) ;
-
-               if ( 0 == memcmp( magic1 , "LUKS\xBA\xBE", 6 ) )
-               {
-                       Glib::ustring temp ;
-                       temp = _( "Linux Unified Key Setup encryption is not yet supported." ) ;
-                       messages .push_back( temp ) ;
-                       return GParted::FS_LUKS ;
-               }
-       }
-
        FS_Info fs_info ;
        Glib::ustring fs_type = "" ;
+       static Glib::ustring luks_unsupported = _("Linux Unified Key Setup encryption is not yet supported.");
 
        //Standard libparted file system detection
        if ( lp_partition && lp_partition ->fs_type )
@@ -1319,6 +1296,11 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
                          fs_type == "linux-swap(old)" ||
                          fs_type == "swap" )
                        return GParted::FS_LINUX_SWAP ;
+               else if ( fs_type == "crypto_LUKS" )
+               {
+                       messages.push_back( luks_unsupported );
+                       return FS_LUKS;
+               }
                else if ( fs_type == "LVM2_member" )
                        return GParted::FS_LVM2_PV ;
                else if ( fs_type == "f2fs" )
@@ -1360,7 +1342,7 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
        // - no patches sent to parted for lvm2, or luks
 
        //reiser4
-       buf = static_cast<char *>( malloc( lp_device ->sector_size ) ) ;
+       char * buf = static_cast<char *>( malloc( lp_device->sector_size ) );
        if ( buf )
        {
                ped_device_open( lp_device );
@@ -1405,6 +1387,23 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
                }
        }
 
+       //LUKS encryption
+       buf = static_cast<char *>( malloc( lp_device->sector_size ) );
+       if ( buf )
+       {
+               ped_device_open( lp_device );
+               ped_geometry_read( & lp_partition->geom, buf, 0, 1 );
+               memcpy(magic1, buf+0, 6);  // set binary magic data
+               ped_device_close( lp_device );
+               free( buf );
+
+               if ( 0 == memcmp( magic1 , "LUKS\xBA\xBE", 6 ) )
+               {
+                       messages.push_back( luks_unsupported );
+                       return FS_LUKS;
+               }
+       }
+
        //btrfs
        const Sector BTRFS_SUPER_INFO_SIZE   = 4096 ;
        const Sector BTRFS_SUPER_INFO_OFFSET = (64 * 1024) ;