[gparted] Support querying whole disk devices for signatures (#741430)

[Curtis Gedak <gedakc src gnome org>]

commit 005a842f2522afe7f37990e8d52da8f7b58f9158
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Wed Dec 24 13:18:07 2014 +0000

    Support querying whole disk devices for signatures (#741430)
    
    Make GParted_Core::get_filesystem() capable of recognising file system
    signatures on whole disk devices.  Pass NULL for lp_partition to make it
    read signatures from the whole disk rather than a specific partition.
    Add debugging to test it works.
    
        # fgrep sdb /proc/partitions
           8    16    8388608 sdb
        # lvm pvcreate /dev/sdb
         Writing physical volume data to disk "/dev/sdb"
         Physical volume "/dev/sdb" successfully created
        # ./gpartedbin
        ======================
        libparted : 1.8.1
        ======================
        Unable to open /dev/sdb - unrecognised disk label.
        DEBUG: /dev/sdb (lvm2 pv)
    
    Bug 741430 - GParted cannot recognise LVM signature on unpartitioned
                 drive

 src/GParted_Core.cc |   58 +++++++++++++++++++++++++++++++++-----------------
 1 files changed, 38 insertions(+), 20 deletions(-)
---
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index fadcf4b..de87510 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -333,9 +333,14 @@ void GParted_Core::set_devices_thread( std::vector<Device> * pdevices )
                                        libparted_messages .clear() ;
                                }
                        }
-                       //harddisk without disklabel
+                       // Hard disk without a libparted recognised disklabel
                        else
                        {
+                               // FIXME: Replace quick test of whole device signature recognition
+                               std::vector<Glib::ustring> dummy;
+                               FILESYSTEM fstype = get_filesystem( lp_device, NULL, dummy );
+                               std::cout << "DEBUG: " << lp_device->path << " (" << 
Utils::get_filesystem_string( fstype ) << ")" << std::endl;
+
                                temp_device .disktype =
                                                /* TO TRANSLATORS:  unrecognized
                                                 * means that the partition table for this
@@ -1295,8 +1300,13 @@ FILESYSTEM GParted_Core::recognise_filesystem_signature( PedDevice * lp_device,
                if ( len1 == 0UL || ( signatures[i].sig2 != NULL && len2 == 0UL ) )
                        continue;  // Don't allow 0 length signatures to match
 
+               Sector start = 0LL;
+               if ( lp_partition )
+                       start = lp_partition->geom.start;
+               start += signatures[i].offset1 / lp_device->sector_size;
+
                memset( buf, 0, lp_device->sector_size );
-               if ( ped_geometry_read( &lp_partition->geom, buf, signatures[i].offset1 / 
lp_device->sector_size, 1 ) != 0 )
+               if ( ped_device_read( lp_device, buf, start, 1 ) != 0 )
                {
                        memcpy( magic1, buf + signatures[i].offset1 % lp_device->sector_size, len1 );
 
@@ -1327,18 +1337,29 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
 {
        FS_Info fs_info ;
        Glib::ustring fsname = "";
+       Glib::ustring path;
        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 )
+       if ( lp_partition )
        {
-               fsname = lp_partition->fs_type->name;
+               path = get_partition_path( lp_partition );
 
-               //TODO:  Temporary code to detect ext4.
-               //       Replace when libparted >= 1.9.0 is chosen as minimum required version.
-               Glib::ustring temp = fs_info .get_fs_type( get_partition_path( lp_partition ) ) ;
-               if ( temp == "ext4" || temp == "ext4dev" )
-                       fsname = temp;
+               // Standard libparted file system detection
+               if ( lp_partition->fs_type )
+               {
+                       fsname = lp_partition->fs_type->name;
+
+                       // TODO: Temporary code to detect ext4.  Replace when
+                       // libparted >= 1.9.0 is chosen as minimum required version.
+                       Glib::ustring temp = fs_info.get_fs_type( path );
+                       if ( temp == "ext4" || temp == "ext4dev" )
+                               fsname = temp;
+               }
+       }
+       else
+       {
+               // Querying whole disk device instead of libparted PedPartition
+               path = lp_device->path;
        }
 
        //FS_Info (blkid) file system detection because current libparted (v2.2) does not
@@ -1346,7 +1367,7 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
        if ( fsname.empty() )
        {
                //TODO: blkid does not return anything for an "extended" partition.  Need to handle this 
somehow
-               fsname = fs_info.get_fs_type( get_partition_path( lp_partition ) );
+               fsname = fs_info.get_fs_type( path );
        }
 
        if ( ! fsname.empty() )
@@ -1412,14 +1433,11 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
        }
 
        // Fallback to GParted simple internal file system detection
-       if ( lp_partition )
-       {
-               FILESYSTEM fstype = recognise_filesystem_signature( lp_device, lp_partition );
-               if ( fstype == FS_LUKS )
-                       messages.push_back( luks_unsupported );
-               if ( fstype != FS_UNKNOWN )
-                       return fstype;
-       }
+       FILESYSTEM fstype = recognise_filesystem_signature( lp_device, lp_partition );
+       if ( fstype == FS_LUKS )
+               messages.push_back( luks_unsupported );
+       if ( fstype != FS_UNKNOWN )
+               return fstype;
 
        //no file system found....
        Glib::ustring  temp = _( "Unable to detect file system! Possible reasons are:" ) ;
@@ -1431,7 +1449,7 @@ GParted::FILESYSTEM GParted_Core::get_filesystem( PedDevice* lp_device, PedParti
        temp += _( "There is no file system available (unformatted)" ) ; 
        temp += "\n- "; 
        /* TO TRANSLATORS: looks like  The device entry /dev/sda5 is missing */
-       temp += String::ucompose( _( "The device entry %1 is missing" ), get_partition_path( lp_partition ) ) 
;
+       temp += String::ucompose( _("The device entry %1 is missing"), path );
        
        messages .push_back( temp ) ;