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/*
* SPDX-FileCopyrightText: 1991 - 1993, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2001 - 2006, Tomasz Kłoczko
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <utmpx.h>
#include "defines.h"
#include "prototypes.h"
#include "shadowlog.h"
#include "sizeof.h"
#include "string/zustr2stp.h"
/*
* Global variables
*/
static const char Prog[] = "logoutd";
#ifndef DEFAULT_HUP_MESG
#define DEFAULT_HUP_MESG _("login time exceeded\n\n")
#endif
#ifndef HUP_MESG_FILE
#define HUP_MESG_FILE "/etc/logoutd.mesg"
#endif
/* local function prototypes */
static int check_login (const struct utmpx *ut);
static void send_mesg_to_tty (int tty_fd);
/*
* check_login - check if user (struct utmpx) allowed to stay logged in
*/
static int
check_login(const struct utmpx *ut)
{
char user[sizeof(ut->ut_user) + 1];
char line[sizeof(ut->ut_line) + 1];
time_t now;
ZUSTR2STP(user, ut->ut_user);
ZUSTR2STP(line, ut->ut_line);
(void) time (&now);
/*
* Check if they are allowed to be logged in right now.
*/
if (!isttytime(user, line, now)) {
return 0;
}
return 1;
}
static void send_mesg_to_tty (int tty_fd)
{
TERMIO oldt, newt;
FILE *mesg_file, *tty_file;
bool is_tty;
tty_file = fdopen (tty_fd, "w");
if (NULL == tty_file) {
return;
}
is_tty = (GTTY (tty_fd, &oldt) == 0);
if (is_tty) {
/* Suggested by Ivan Nejgebauar <ian@unsux.ns.ac.yu>:
set OPOST before writing the message. */
newt = oldt;
newt.c_oflag |= OPOST;
STTY (tty_fd, &newt);
}
mesg_file = fopen (HUP_MESG_FILE, "r");
if (NULL != mesg_file) {
int c;
while ((c = getc (mesg_file)) != EOF) {
if (c == '\n') {
putc ('\r', tty_file);
}
putc (c, tty_file);
}
fclose (mesg_file);
} else {
fputs (DEFAULT_HUP_MESG, tty_file);
}
fflush (tty_file);
fclose (tty_file);
if (is_tty) {
STTY (tty_fd, &oldt);
}
}
/*
* logoutd - logout daemon to enforce /etc/porttime file policy
*
* logoutd is started at system boot time and enforces the login
* time and port restrictions specified in /etc/porttime. The
* utmp file is periodically scanned and offending users are logged
* off from the system.
*/
int
main(int argc, char **argv)
{
int i;
int status;
pid_t pid;
struct utmpx *ut;
char user[sizeof (ut->ut_user) + 1]; /* terminating NUL */
char tty_name[sizeof (ut->ut_line) + 6]; /* /dev/ + NUL */
int tty_fd;
if (1 != argc) {
(void) fputs (_("Usage: logoutd\n"), stderr);
}
(void) setlocale (LC_ALL, "");
(void) bindtextdomain (PACKAGE, LOCALEDIR);
(void) textdomain (PACKAGE);
#ifndef DEBUG
for (i = 0; close (i) == 0; i++);
setpgrp ();
/*
* Put this process in the background.
*/
pid = fork ();
if (pid > 0) {
/* parent */
exit (EXIT_SUCCESS);
} else if (pid < 0) {
/* error */
perror ("fork");
exit (EXIT_FAILURE);
}
#endif /* !DEBUG */
/*
* Start syslogging everything
*/
log_set_progname(Prog);
log_set_logfd(stderr);
OPENLOG (Prog);
/*
* Scan the utmp file once per minute looking for users that
* are not supposed to still be logged in.
*/
while (true) {
/*
* Attempt to re-open the utmp file. The file is only
* open while it is being used.
*/
setutxent();
/*
* Read all of the entries in the utmp file. The entries
* for login sessions will be checked to see if the user
* is permitted to be signed on at this time.
*/
while ((ut = getutxent()) != NULL) {
if (ut->ut_type != USER_PROCESS) {
continue;
}
if (ut->ut_user[0] == '\0') {
continue;
}
if (check_login (ut)) {
continue;
}
/*
* Put the rest of this in a child process. This
* keeps the scan from waiting on other ports to die.
*/
pid = fork ();
if (pid > 0) {
/* parent */
continue;
} else if (pid < 0) {
/* failed - give up until the next scan */
break;
}
/* child */
if (strncmp (ut->ut_line, "/dev/", 5) != 0) {
strcpy (tty_name, "/dev/");
} else {
tty_name[0] = '\0';
}
strncat(tty_name, ut->ut_line, NITEMS(ut->ut_line));
#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif
tty_fd =
open (tty_name, O_WRONLY | O_NDELAY | O_NOCTTY);
if (tty_fd != -1) {
send_mesg_to_tty (tty_fd);
close (tty_fd);
sleep (10);
}
if (ut->ut_pid > 1) {
kill (-ut->ut_pid, SIGHUP);
sleep (10);
kill (-ut->ut_pid, SIGKILL);
}
ZUSTR2STP(user, ut->ut_user);
SYSLOG ((LOG_NOTICE,
"logged off user '%s' on '%s'", user,
tty_name));
/*
* This child has done all it can, drop dead.
*/
exit (EXIT_SUCCESS);
}
endutxent();
#ifndef DEBUG
sleep (60);
#endif
/*
* Reap any dead babies ...
*/
while (wait (&status) != -1);
}
return EXIT_FAILURE;
}
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