summaryrefslogtreecommitdiff
path: root/src/logoutd.c
blob: 1503a743ac61f49f8e16840256c126227986b40f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
/*
 * 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
 */
const 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;
	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
 *	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;
}