/*
 * Some of the MPLE magic bytes are set from the media serial number
 * in the FAT header. This data is not accessible to non-root
 * users. This is a small helper program to read the data. Note, it
 * can read arbitrary devices, but only 4 bytes at 0x27.
 */
#include <stdio.h>
#include <errno.h>
#include <glib.h>
#include <string.h>
#include "mple.h"

/* this is the allowed device prefix. anything else will be rejected */
#define DEVICE_PREFIX "/dev/sd"

int main( int argc, char *argv[] ) {
  mple_device device;

  if (( argc != 2 ) || strncmp( argv[1], DEVICE_PREFIX,
                                strlen( DEVICE_PREFIX ))) {
    fprintf( stderr, "usage: %s %s...\n", argv[0], DEVICE_PREFIX );
    return 1;
  }

  memset( &device, 0, sizeof( device ));
  device.device = g_strdup( argv[1] );

  errno = 0;
  if ( mple_get_media_serial_number( &device )) {
    printf( "%08x\n", device.msn );
    return 0;
  } else {
    perror( "get_msn" );
    return 1;
  }
}