ttyslot.c revision 5d54f3d8999eac1762fe0a8c7177d20f1f201fae
/*
* Copyright 1991 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.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* 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_open, "/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);
}