shadow/src/logoutd.c

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/*
* Copyright (c) 1991 - 1993, Julianne Frances Haugh
* Copyright (c) 1996 - 2000, Marek Michałkiewicz
* Copyright (c) 2001 - 2006, Tomasz Kłoczko
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#ident "$Id$"
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "defines.h"
#include "prototypes.h"
/*
* Global variables
*/
char *Prog;
#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 */
#ifdef USE_UTMPX
static int check_login (const struct utmpx *ut);
#else /* !USE_UTMPX */
static int check_login (const struct utmp *ut);
#endif /* !USE_UTMPX */
static void send_mesg_to_tty (int tty_fd);
/*
* check_login - check if user (struct utmpx/utmp) allowed to stay logged in
*/
#ifdef USE_UTMPX
static int check_login (const struct utmpx *ut)
#else /* !USE_UTMPX */
static int check_login (const struct utmp *ut)
#endif /* !USE_UTMPX */
{
char user[sizeof (ut->ut_user) + 1];
time_t now;
/*
* ut_user may not have the terminating NUL.
*/
strncpy (user, ut->ut_user, sizeof (ut->ut_user));
user[sizeof (ut->ut_user)] = '\0';
(void) time (&now);
/*
* Check if they are allowed to be logged in right now.
*/
if (!isttytime (user, ut->ut_line, now)) {
return 0;
}
return 1;
}
static void send_mesg_to_tty (int tty_fd)
{
TERMIO oldt, newt;
FILE *mesg_file, *tty_file;
int c;
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) {
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
* utmpx/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;
#ifdef USE_UTMPX
struct utmpx *ut;
#else /* !USE_UTMPX */
struct utmp *ut;
#endif /* !USE_UTMPX */
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
*/
Prog = Basename (argv[0]);
OPENLOG ("logoutd");
/*
* Scan the utmpx/utmp file once per minute looking for users that
* are not supposed to still be logged in.
*/
while (true) {
/*
* Attempt to re-open the utmpx/utmp file. The file is only
* open while it is being used.
*/
#ifdef USE_UTMPX
setutxent ();
#else /* !USE_UTMPX */
setutent ();
#endif /* !USE_UTMPX */
/*
* Read all of the entries in the utmpx/utmp file. The entries
* for login sessions will be checked to see if the user
* is permitted to be signed on at this time.
*/
#ifdef USE_UTMPX
while ((ut = getutxent ()) != NULL)
#else /* !USE_UTMPX */
while ((ut = getutent ()) != NULL)
#endif /* !USE_UTMPX */
{
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';
}
strcat (tty_name, 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);
}
strncpy (user, ut->ut_user, sizeof (user) - 1);
user[sizeof (user) - 1] = '\0';
SYSLOG ((LOG_NOTICE,
"logged off user '%s' on '%s'", user,
tty_name));
/*
* This child has done all it can, drop dead.
*/
exit (EXIT_SUCCESS);
}
#ifdef USE_UTMPX
endutxent ();
#else /* !USE_UTMPX */
endutent ();
#endif /* !USE_UTMPX */
#ifndef DEBUG
sleep (60);
#endif
/*
* Reap any dead babies ...
*/
while (wait (&status) != -1);
}
return EXIT_FAILURE;
}