source: trunk/minix/lib/other/ttyslot.c@ 20

/*
ttyslot.c

Return the index in the utmp file for the current user's terminal. The 
current user's terminal is the first file descriptor in the range 0..2
for which ttyname() returns a name. The index is the line number in the
/etc/ttytab file. 0 will be returned in case of an error.

Created:        Oct 11, 1992 by Philip Homburg
*/

#define _MINIX_SOURCE

#include <sys/types.h>
#include <ttyent.h>
#include <string.h>
#include <unistd.h>

int ttyslot()
{
        int slot;

        slot= fttyslot(0);
        if (slot == 0) slot= fttyslot(1);
        if (slot == 0) slot= fttyslot(2);
        return slot;
}

int fttyslot(fd)
int fd;
{
        char *tname;
        int lineno;
        struct ttyent *ttyp;

        tname= ttyname(fd);
        if (tname == NULL) return 0;

        /* Assume that tty devices are in /dev */
        if (strncmp(tname, "/dev/", 5) != 0)
                return 0;       /* Malformed tty name. */
        tname += 5;

        /* Scan /etc/ttytab. */
        lineno= 1;
        while ((ttyp= getttyent()) != NULL)
        {
                if (strcmp(tname, ttyp->ty_name) == 0)
                {
                        endttyent();
                        return lineno;
                }
                lineno++;
        }
        /* No match */
        endttyent();
        return 0;
}

/*
 * $PchHeader: /mount/hd2/minix/lib/misc/RCS/ttyslot.c,v 1.3 1994/12/22 13:49:12 philip Exp $
 */