A question on the implementation of /dev/stdin, etc.

[Boyd Roberts]

In article <[2643142a:635.16]comp.unix.wizards;1 at wcbcs> akcs.kevin at wcbcs (Kevin Schoedel) writes:
>This discussion has prompted me to try to implement /dev/fd/... for
>System V 3.2 on a 386.  I don't have kernel source, so I can't use the
>   case IFCHR:

Yes, do it as a device driver.  But...  you'll have to cheat!

Grody hack follows:

    fdopen(dev, mode)
    dev_t   dev;
    int	    mode;
    {
	/* u_rval1 should hold the allocated file descriptor -- gag! */

	closef(u.u_ofile[u.u_rval1]);

	if (u.u_error)
	    return;

	if (u.u_ofile[minor(dev)] != NULL)
	{
	    /* fake dup */
	    u.u_ofile[u.u_rval1] = u.u_ofile[minor(dev)];
	    u.u_ofile[minor(dev)]->f_count++;
	}
	else
	    u.u_error = EBADF;
    }


Boyd Roberts			boyd at necisa.ho.necisa.oz.au

``When the going gets wierd, the weird turn pro...''