Binary writing to an input pipe and ASCII reading from an output one

[Colossus <colossus 3000 it>]

Hi,

I'm trying without success to implement cat /tmp/file.cpio | cpio -tv 
with g_spawn family and giochannels. My code is to use 
"g_spawn_async_with_pipes" with both input and output pipes the "cpio 
-tv" command and then I open in read mode the binary cpio archive (I 
don't spawn cat just use g_io_channel_new_file):

gchar buffer[65536];
gsize bytes_read;
GError *error = NULL;
GIOChannel *ioc , *input_ioc;

 compressor_pid = SpawnAsyncProcess ( "cpio -tv" , 0 , 1);
    if ( compressor_pid == 0 )
    {
        unlink ( tmp );
        g_free (tmp);
        return;
    }
    SetIOChannel (error_fd, 
G_IO_IN|G_IO_PRI|G_IO_ERR|G_IO_HUP|G_IO_NVAL,GenError, NULL );
    SetIOChannel (output_fd, 
G_IO_IN|G_IO_PRI|G_IO_ERR|G_IO_HUP|G_IO_NVAL,ReadCPIOOutput, NULL );

    input_ioc = SetIOChannel (input_fd, G_IO_IN|G_IO_PRI , NULL, NULL);
    //The second parameter is set to NULL because the CPIO archive is 
binary
    g_io_channel_set_encoding (input_ioc, NULL , NULL);
    //tmp contains the filename of the binary cpio archive
    ioc = g_io_channel_new_file ( tmp , "r" , NULL );
        g_io_channel_set_encoding (ioc, NULL , NULL);
    g_io_channel_set_flags ( ioc , G_IO_FLAG_NONBLOCK , NULL );

	while ( g_io_channel_read_chars ( ioc, buffer, sizeof(buffer), 
&bytes_read, &error ) == G_IO_STATUS_NORMAL )
    {
        if ( error != NULL )
        {
            g_print ("Read Error: %s\n",error->message);
            g_error_free ( error );
            g_io_channel_shutdown ( ioc,TRUE,NULL );
                    g_io_channel_unref (ioc);
                    g_spawn_close_pid ( child_pid );
            g_free (tmp);
        }

        status = g_io_channel_write_chars ( input_ioc , buffer , 
sizeof(buffer) , NULL , &error );
        if ( status == G_IO_STATUS_ERROR )
        {
            g_print ("Write Error: %s\n",error->message);
            g_error_free ( error );
            g_io_channel_shutdown ( ioc,TRUE,NULL );
                    g_io_channel_unref (ioc);
                    g_spawn_close_pid ( child_pid );
            g_free (tmp);
        }
    }

Sometimes the console gives no output but the output of the command 
cpio (redirected in a GtkTextBuffer) is:

cpio: warning: skipped 7099 bytes of junk
cpio: warning: skipped 13776 bytes of junk
cpio: warning: skipped 22769 bytes of junk
cpio: warning: skipped 104333 bytes of junk

while some other times the output (the list of files in the cpio 
archive) is incomplete. I believed is was a matter of encoding but the 
cpio archive is binary I'm sure of this while its ouput is ASCII and I 
have correctly set the encoding, so what can be ?
--
Colossus
Xarchiver, a GTK2 only archive manager - http://xarchiver.sourceforge.net
Cpsed, a Linux OpenGL 3D scene editor - http://cpsed.sourceforge.net
Mizio, a QT proxy hunter scanner tool - http://mizio.sourceforge.net