[gparted] Use wipefs to clear old signatures before creating new file systems (#688882)

[Curtis Gedak <gedakc src gnome org>]

commit 3c75f3f5b103bc158b0f70ea63459aa362b0bab8
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sat Dec 1 12:49:29 2012 +0000

    Use wipefs to clear old signatures before creating new file systems (#688882)
    
    Previously the function erase_filesystem_signatures() was used to clear
    file system signatures when a new partition was created and when an
    existing partition was formatted with a file system.  However this was
    only available with libparted <= 2.4 and then only for the file systems
    which libparted supports.
    
    Having multiple different file system signatures on a partition leads to
    misidentification of file system.  For example creating a nilfs2 over
    the top of a fat32 file system is detected as a fat32, not nilfs2.  This
    shows that old file system signatures must be cleared before a new file
    system is created.
    
    Fix by always using "wipefs -a /dev/PARTITION" command to clear all old
    file system signatures rather than libparted API calls.  Failure from
    wipefs is only considered a warning so doesn't fail the file system
    creation.  (This doesn't yet fully meet the "MUST be cleared"
    requirement above.  Will be fully met later in this patchset).  Output
    from the wipefs command is displayed as a new sub-step which looks like
    this:
    
        v Format /dev/sda7 as xfs                            00:00:05
          > calibrate /dev/sda14                             00:00:01
          v clear old file system signatures in /dev/sda7    00:00:01  [NEW]
            > wipefs -a /dev/sda7                                      [NEW]
          > set partition type on /dev/sda7                  00:00:02
          v create new xfs file system                       00:00:01
            > mkfs.xfs -f -L "" /dev/sda7
    
    Also signatures are only cleared immediately before a new file system is
    written and not when an unformatted partition is created.  This allows
    recovery from accidental partition deletion by re-creating the deleted
    partition as unformatted.
    
    Bug #688882 - Improve clearing of file system signatures

 include/GParted_Core.h |    4 +--
 src/GParted_Core.cc    |   61 ++++++++++++++++++-----------------------------
 2 files changed, 24 insertions(+), 41 deletions(-)
---
diff --git a/include/GParted_Core.h b/include/GParted_Core.h
index 6eb533e..da4b0c0 100644
--- a/include/GParted_Core.h
+++ b/include/GParted_Core.h
@@ -178,9 +178,7 @@ private:
                                   Partition & partition_new,
                                   OperationDetail & operationdetail ) ;
        FileSystem* set_proper_filesystem( const FILESYSTEM & filesystem ) ;
-#ifndef HAVE_LIBPARTED_3_0_0_PLUS
-       bool erase_filesystem_signatures( const Partition & partition ) ;
-#endif
+       bool erase_filesystem_signatures( const Partition & partition, OperationDetail & operationdetail ) ;
        bool update_bootsector( const Partition & partition, OperationDetail & operationdetail ) ;
 
        //general..     
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index 7ac3368..cc48a91 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -1700,8 +1700,9 @@ bool GParted_Core::create( const Device & device, Partition & new_partition, Ope
                if ( new_partition .filesystem == GParted::FS_UNFORMATTED )
                        return true ;
                else
-                       return set_partition_type( new_partition, operationdetail ) &&
-                              create_filesystem( new_partition, operationdetail ) ;
+                       return    erase_filesystem_signatures( new_partition, operationdetail )
+                              && set_partition_type( new_partition, operationdetail )
+                              && create_filesystem( new_partition, operationdetail ) ;
        }
        
        return false ;
@@ -1796,11 +1797,7 @@ bool GParted_Core::create_partition( Partition & new_partition, OperationDetail
                close_device_and_disk( lp_device, lp_disk ) ;
        }
 
-       bool succes = new_partition .partition_number > 0
-#ifndef HAVE_LIBPARTED_3_0_0_PLUS
-                     && erase_filesystem_signatures( new_partition )
-#endif
-       ;
+       bool succes = new_partition .partition_number > 0 ;
 
 #ifndef USE_LIBPARTED_DMRAID
        //create dev map entries if dmraid
@@ -1849,12 +1846,9 @@ bool GParted_Core::create_filesystem( const Partition & partition, OperationDeta
 
 bool GParted_Core::format( const Partition & partition, OperationDetail & operationdetail )
 {
-#ifndef HAVE_LIBPARTED_3_0_0_PLUS
-       //remove all file system signatures...
-       erase_filesystem_signatures( partition ) ;
-#endif
-
-       return set_partition_type( partition, operationdetail ) && create_filesystem( partition, 
operationdetail ) ;
+       return    erase_filesystem_signatures( partition, operationdetail )
+              && set_partition_type( partition, operationdetail )
+              && create_filesystem( partition, operationdetail ) ;
 }
 
 bool GParted_Core::Delete( const Partition & partition, OperationDetail & operationdetail ) 
@@ -3123,36 +3117,27 @@ bool GParted_Core::filesystem_resize_disallowed( const Partition & partition )
        return false ;
 }
 
-#ifndef HAVE_LIBPARTED_3_0_0_PLUS
-bool GParted_Core::erase_filesystem_signatures( const Partition & partition ) 
+bool GParted_Core::erase_filesystem_signatures( const Partition & partition, OperationDetail & 
operationdetail )
 {
-       bool return_value = false ;
-
-       PedDevice* lp_device = NULL ;
-       PedDisk* lp_disk = NULL ;
-       if ( open_device_and_disk( partition .device_path, lp_device, lp_disk ) )
+       if ( ! Glib::find_program_in_path( "wipefs" ) .empty() )
        {
-               PedPartition* lp_partition = ped_disk_get_partition_by_sector( lp_disk, partition 
.get_sector() ) ;
-
-               if ( lp_partition && ped_file_system_clobber( & lp_partition ->geom ) )
-               {
-                       //file systems not yet supported by libparted
-                       if ( ped_device_open( lp_device ) )
-                       {
-                               //reiser4 stores "ReIsEr4" at sector 128 with a sector size of 512 bytes
-                               // FIXME writing block of partially uninitialized bytes (security/privacy)
-                               return_value = ped_geometry_write( & lp_partition ->geom, "0000000", (65536 / 
lp_device ->sector_size), 1 ) ;
-
-                               ped_device_close( lp_device ) ;
-                       }
-               }
-               
-               close_device_and_disk( lp_device, lp_disk ) ;
+               operationdetail .add_child( OperationDetail(
+                               String::ucompose( _("clear old file system signatures in %1"),
+                                                 partition .get_path() ) ) ) ;
+               OperationDetail & od = operationdetail .get_last_child() ;
+               Glib::ustring output, error ;
+               Glib::ustring command = "wipefs -a " + partition .get_path() ;
+               od .add_child( OperationDetail( command, STATUS_NONE, FONT_BOLD_ITALIC ) ) ;
+               int exit_status = Utils::execute_command( command, output, error, true ) ;
+               if ( ! output .empty() )
+                       od .get_last_child() .add_child( OperationDetail( output, STATUS_NONE, FONT_ITALIC ) 
) ;
+               if ( ! error .empty() )
+                       od .get_last_child() .add_child( OperationDetail( error, STATUS_NONE, FONT_ITALIC ) ) 
;
+               od .set_status( exit_status == 0 ? STATUS_SUCCES : STATUS_N_A ) ;
        }
 
-       return return_value ;
+       return true ;
 }
-#endif
 
 bool GParted_Core::update_bootsector( const Partition & partition, OperationDetail & operationdetail ) 
 {