1/*	$NetBSD: utmpentry.c,v 1.16 2008/10/28 14:01:46 christos Exp $	*/
2
3/*-
4 * Copyright (c) 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#ifndef lint
34__RCSID("$NetBSD: utmpentry.c,v 1.16 2008/10/28 14:01:46 christos Exp $");
35#endif
36
37#include <sys/stat.h>
38
39#include <time.h>
40#include <string.h>
41#include <err.h>
42#include <stdlib.h>
43
44#ifdef SUPPORT_UTMP
45#include <utmp.h>
46#endif
47#ifdef SUPPORT_UTMPX
48#include <utmpx.h>
49#endif
50
51#include "utmpentry.h"
52
53
54/* Fail the compile if x is not true, by constructing an illegal type. */
55#define COMPILE_ASSERT(x) /*LINTED null effect */ \
56	((void)sizeof(struct { unsigned : ((x) ? 1 : -1); }))
57
58
59#ifdef SUPPORT_UTMP
60static void getentry(struct utmpentry *, struct utmp *);
61static struct timespec utmptime = {0, 0};
62#endif
63#ifdef SUPPORT_UTMPX
64static void getentryx(struct utmpentry *, struct utmpx *);
65static struct timespec utmpxtime = {0, 0};
66#endif
67#if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
68static int setup(const char *);
69static void adjust_size(struct utmpentry *e);
70#endif
71
72int maxname = 8, maxline = 8, maxhost = 16;
73int etype = 1 << USER_PROCESS;
74static int numutmp = 0;
75static struct utmpentry *ehead;
76
77#if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
78static void
79adjust_size(struct utmpentry *e)
80{
81	int max;
82
83	if ((max = strlen(e->name)) > maxname)
84		maxname = max;
85	if ((max = strlen(e->line)) > maxline)
86		maxline = max;
87	if ((max = strlen(e->host)) > maxhost)
88		maxhost = max;
89}
90
91static int
92setup(const char *fname)
93{
94	int what = 3;
95	struct stat st;
96	const char *sfname;
97
98	if (fname == NULL) {
99#ifdef SUPPORT_UTMPX
100		setutxent();
101#endif
102#ifdef SUPPORT_UTMP
103		setutent();
104#endif
105	} else {
106		size_t len = strlen(fname);
107		if (len == 0)
108			errx(1, "Filename cannot be 0 length.");
109		what = fname[len - 1] == 'x' ? 1 : 2;
110		if (what == 1) {
111#ifdef SUPPORT_UTMPX
112			if (utmpxname(fname) == 0)
113				warnx("Cannot set utmpx file to `%s'",
114				    fname);
115#else
116			warnx("utmpx support not compiled in");
117#endif
118		} else {
119#ifdef SUPPORT_UTMP
120			if (utmpname(fname) == 0)
121				warnx("Cannot set utmp file to `%s'",
122				    fname);
123#else
124			warnx("utmp support not compiled in");
125#endif
126		}
127	}
128#ifdef SUPPORT_UTMPX
129	if (what & 1) {
130		sfname = fname ? fname : _PATH_UTMPX;
131		if (stat(sfname, &st) == -1) {
132			warn("Cannot stat `%s'", sfname);
133			what &= ~1;
134		} else {
135			if (timespeccmp(&st.st_mtimespec, &utmpxtime, >))
136			    utmpxtime = st.st_mtimespec;
137			else
138			    what &= ~1;
139		}
140	}
141#endif
142#ifdef SUPPORT_UTMP
143	if (what & 2) {
144		sfname = fname ? fname : _PATH_UTMP;
145		if (stat(sfname, &st) == -1) {
146			warn("Cannot stat `%s'", sfname);
147			what &= ~2;
148		} else {
149			if (timespeccmp(&st.st_mtimespec, &utmptime, >))
150				utmptime = st.st_mtimespec;
151			else
152				what &= ~2;
153		}
154	}
155#endif
156	return what;
157}
158#endif
159
160void
161endutentries(void)
162{
163	struct utmpentry *ep;
164
165#ifdef SUPPORT_UTMP
166	timespecclear(&utmptime);
167#endif
168#ifdef SUPPORT_UTMPX
169	timespecclear(&utmpxtime);
170#endif
171	ep = ehead;
172	while (ep) {
173		struct utmpentry *sep = ep;
174		ep = ep->next;
175		free(sep);
176	}
177	ehead = NULL;
178	numutmp = 0;
179}
180
181int
182getutentries(const char *fname, struct utmpentry **epp)
183{
184#ifdef SUPPORT_UTMPX
185	struct utmpx *utx;
186#endif
187#ifdef SUPPORT_UTMP
188	struct utmp *ut;
189#endif
190#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
191	struct utmpentry *ep;
192	int what = setup(fname);
193	struct utmpentry **nextp = &ehead;
194	switch (what) {
195	case 0:
196		/* No updates */
197		*epp = ehead;
198		return numutmp;
199	default:
200		/* Need to re-scan */
201		ehead = NULL;
202		numutmp = 0;
203	}
204#endif
205
206#ifdef SUPPORT_UTMPX
207	while ((what & 1) && (utx = getutxent()) != NULL) {
208		if (fname == NULL && ((1 << utx->ut_type) & etype) == 0)
209			continue;
210		if ((ep = calloc(1, sizeof(struct utmpentry))) == NULL) {
211			warn(NULL);
212			return 0;
213		}
214		getentryx(ep, utx);
215		*nextp = ep;
216		nextp = &(ep->next);
217	}
218#endif
219
220#ifdef SUPPORT_UTMP
221	if ((etype & (1 << USER_PROCESS)) != 0) {
222		while ((what & 2) && (ut = getutent()) != NULL) {
223			if (fname == NULL && (*ut->ut_name == '\0' ||
224			    *ut->ut_line == '\0'))
225				continue;
226			/* Don't process entries that we have utmpx for */
227			for (ep = ehead; ep != NULL; ep = ep->next) {
228				if (strncmp(ep->line, ut->ut_line,
229				    sizeof(ut->ut_line)) == 0)
230					break;
231			}
232			if (ep != NULL)
233				continue;
234			if ((ep = calloc(1, sizeof(*ep))) == NULL) {
235				warn(NULL);
236				return 0;
237			}
238			getentry(ep, ut);
239			*nextp = ep;
240			nextp = &(ep->next);
241		}
242	}
243#endif
244	numutmp = 0;
245#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
246	if (ehead != NULL) {
247		struct utmpentry *from = ehead, *save;
248
249		ehead = NULL;
250		while (from != NULL) {
251			for (nextp = &ehead;
252			    (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
253			    nextp = &(*nextp)->next)
254				continue;
255			save = from;
256			from = from->next;
257			save->next = *nextp;
258			*nextp = save;
259			numutmp++;
260		}
261	}
262	*epp = ehead;
263	return numutmp;
264#else
265	*epp = NULL;
266	return 0;
267#endif
268}
269
270#ifdef SUPPORT_UTMP
271static void
272getentry(struct utmpentry *e, struct utmp *up)
273{
274	COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
275	COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
276	COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
277
278	/*
279	 * e has just been calloc'd. We don't need to clear it or
280	 * append null-terminators, because its length is strictly
281	 * greater than the source string. Use strncpy to _read_
282	 * up->ut_* because they may not be terminated. For this
283	 * reason we use the size of the _source_ as the length
284	 * argument.
285	 */
286	(void)strncpy(e->name, up->ut_name, sizeof(up->ut_name));
287	(void)strncpy(e->line, up->ut_line, sizeof(up->ut_line));
288	(void)strncpy(e->host, up->ut_host, sizeof(up->ut_host));
289
290	e->tv.tv_sec = up->ut_time;
291	e->tv.tv_usec = 0;
292	e->pid = 0;
293	e->term = 0;
294	e->exit = 0;
295	e->sess = 0;
296	e->type = USER_PROCESS;
297	adjust_size(e);
298}
299#endif
300
301#ifdef SUPPORT_UTMPX
302static void
303getentryx(struct utmpentry *e, struct utmpx *up)
304{
305	COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
306	COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
307	COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
308
309	/*
310	 * e has just been calloc'd. We don't need to clear it or
311	 * append null-terminators, because its length is strictly
312	 * greater than the source string. Use strncpy to _read_
313	 * up->ut_* because they may not be terminated. For this
314	 * reason we use the size of the _source_ as the length
315	 * argument.
316	 */
317	(void)strncpy(e->name, up->ut_name, sizeof(up->ut_name));
318	(void)strncpy(e->line, up->ut_line, sizeof(up->ut_line));
319	(void)strncpy(e->host, up->ut_host, sizeof(up->ut_host));
320
321	e->tv = up->ut_tv;
322	e->pid = up->ut_pid;
323	e->term = up->ut_exit.e_termination;
324	e->exit = up->ut_exit.e_exit;
325	e->sess = up->ut_session;
326	e->type = up->ut_type;
327	adjust_size(e);
328}
329#endif
330