INT 21 - DR-DOS 3.41+ internal - GET ACCESS RIGHTS
        AX = 4302h
        DS:DX -> ASCIZ pathname
Return: CF clear if successful
            CX = access rights (see below)
            AX = CX (DR-DOS 5.0)
        CF set on error
            AX = error code
Desc:   Determine which operations the calling program may perform on a
          specified file without being required to provide a password.
Notes:  this protection scheme has been coordinated on all current Digital
          Research/Novell operating systems (DR-DOS 3.41+, DRMDOS 5.x, and
          FlexOS 2+)
        this function is documented in DR-DOS 6.0 and corresponds to the
          "Get/Set File Attributes" function, subfunction 2, documented in
          Concurrent DOS.
        only FlexOS actually uses the "execution" bits; DR-DOS 3.41+ treats
          them as "read" bits.
        DR-DOS 3.41-5.x only use bits 0-3.  Only DR-DOS 6.0 using a
          DRMDOS 5.x security system allowing for users and groups uses bits
          4-11.
SeeAlso: AX=4303h

Bitfields for access rights:
 bit 0  owner delete requires password
 bit 1  owner execution requires password (FlexOS)
 bit 2  owner write requires password
 bit 3  owner read requires password
 bit 4  group delete requires password
 bit 5  group execution requires password (FlexOS)
 bit 6  group write requires password
 bit 7  group read requires password
 bit 8  world delete requires password
 bit 9  world execution requires password (FlexOS)
 bit 10 world write requires password
 bit 11 world read requires password

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