ttyslot.c revision 8fd04b8338ed5093ec2d1e668fa620b7de44c177
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 1984 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
/*
* Return the number of the slot in the utmp file
* corresponding to the current user: try for file 0, 1, 2.
* To mimic the behavior of getttyent, we loop through utmp
* and try to find an entry with a matching line number.
* If we don't find one we return the index of the end of
* the file, so that the record can be added to the end of
* the file.
*/
#include "../../sys/common/compat.h"
#include <sys/syscall.h>
#include <sys/fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <strings.h>
int
ttyslot(void)
{
char *tp, *p;
int s;
int fd;
struct utmpx utx;
if ((tp = ttyname(0)) == NULL &&
(tp = ttyname(1)) == NULL &&
(tp = ttyname(2)) == NULL)
return (0);
if ((p = rindex(tp, '/')) == NULL)
p = tp;
else
p++;
if ((fd = _syscall(SYS_openat,
AT_FDCWD, "/etc/utmpx", O_RDONLY)) == -1) {
perror("ttyslot: open of /etc/utmpx failed:");
return (0);
}
s = 0;
while (_read(fd, &utx, sizeof (struct utmpx)) > 0) {
s++;
if (strncmp(utx.ut_line, p, sizeof (utx.ut_line)) == 0) {
_syscall(SYS_close, fd);
return (s);
}
}
_syscall(SYS_close, fd);
return (s);
}