[Libcdio-devel] Bug report: run_mmc_cmd_linux() does only direction READ

[Thomas Schmitt]

Hi,

it appears that run_mmc_cmd_linux() in
libcdio-0.82/lib/driver/gnu_linux.c
works only for transfer direction CGC_DATA_READ
and this only by accident.

I read:

  static driver_return_code_t
  run_mmc_cmd_linux( void *p_user_data,
  ...
                     cdio_mmc_direction_t e_direction,
  ...
  {
  ...
    memset (&cgc, 0, sizeof (struct cdrom_generic_command));
  ...
    cgc.data_direction = (SCSI_MMC_DATA_READ == cgc.data_direction)
      ? CGC_DATA_READ : CGC_DATA_WRITE;

This ignores parameter e_direction and always
yields CGC_DATA_READ because SCSI_MMC_DATA_READ
is 0 and cgc.data_direction is initialized 0.

The statement should rather be

    cgc.data_direction = (SCSI_MMC_DATA_READ == e_direction)
      ? CGC_DATA_READ : CGC_DATA_WRITE;

and even then there is no way to express
direction CGC_DATA_NONE.
The libcdio API does not define a
  SCSI_MMC_DATA_NONE

I checked in growisofs. It uses all three
CGC_DATA_* macros when using CDROM_SEND_PACKET.


Have a nice day :)

Thomas