stdin doesn't work

[stsp]

Reading from stdin always returns error.

[stsp]

get_sft_idx() returns DE_INVLDHNDL with
this code:

  idx = p->ps_filetab[hndl];
  return idx == 0xff ? DE_INVLDHNDL : idx;

so p->ps_filetab[0] == 0xff, which causes
the error to be returned when reading from stdin.

@bartoldeman Could you please hint me where
to look? Where should the ps_filetab be initialized
for stdin?
I also see this code:

/* if the sft is invalid, then we just monitor syscon */
struct dhdr FAR *sft_to_dev(sft FAR *s)
{
  if (FP_OFF(s) == (UWORD) -1)
    return syscon;

but DosRWSft() doesn't have such fall-back.

[stsp]

OK, looks like FsConfig() does this.
Looking...

[stsp]

OK, the bug seems to be in truename().
It gets called to open AUX and errors here:

  dhp = IsDevice(src);
    
  cdsEntry = get_cds(result);
  if (cdsEntry == NULL)
  {
    /* workaround for a device prefixed with invalid drive (e.g. "@:NUL") */
    /* (MS-DOS always return drive P: for invalid drive. Why P:?) */
    if (dhp)
    {
      result = default_drive;
      cdsEntry = get_cds(result);
      if (cdsEntry == NULL)
        return DE_PATHNOTFND;
    }

So it correctly finds device header, but,
since I have no drives defined, it can't
find CDS for default_drive and returns
an error. IMHO when opening the devices
like AUX, the missing drive should not
cause any failure. So I think this is a freedos
bug.
@bartoldeman Could you please clarify?