1/* $NetBSD: utmpentry.c,v 1.22 2021/02/26 02:45:43 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 1.22 2021/02/26 02:45:43 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#define COMPILE_ASSERT(x) ((void)0)
55
56
57#ifdef SUPPORT_UTMP
58static void getentry(struct utmpentry *, struct utmp *);
59static struct timespec utmptime = {0, 0};
60#endif
61#ifdef SUPPORT_UTMPX
62static void getentryx(struct utmpentry *, struct utmpx *);
63static struct timespec utmpxtime = {0, 0};
64#endif
65#if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
66static int setup(const char *);
67static void adjust_size(struct utmpentry *e);
68#endif
69
70size_t maxname = 8, maxline = 8, maxhost = 16;
71int etype = 1 << USER_PROCESS;
72static size_t numutmp = 0;
73static struct utmpentry *ehead;
74
75#if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
76static void
77adjust_size(struct utmpentry *e)
78{
79 size_t max;
80
81 if ((max = strlen(e->name)) > maxname)
82 maxname = max;
83 if ((max = strlen(e->line)) > maxline)
84 maxline = max;
85 if ((max = strlen(e->host)) > maxhost)
86 maxhost = max;
87}
88
89static int
90setup(const char *fname)
91{
92 int what = 3;
93 struct stat st;
94 const char *sfname;
95
96 if (fname != NULL) {
97 size_t len = strlen(fname);
98 if (len == 0)
99 errx(1, "Filename cannot be 0 length.");
100 what = fname[len - 1] == 'x' ? 1 : 2;
101 if (what == 1) {
102#ifdef SUPPORT_UTMPX
103 if (utmpxname(fname) == 0)
104 warnx("Cannot set utmpx file to `%s'",
105 fname);
106#else
107 warnx("utmpx support not compiled in");
108#endif
109 } else {
110#ifdef SUPPORT_UTMP
111 if (utmpname(fname) == 0)
112 warnx("Cannot set utmp file to `%s'",
113 fname);
114#else
115 warnx("utmp support not compiled in");
116#endif
117 }
118 }
119#ifdef SUPPORT_UTMPX
120 if (what & 1) {
121 sfname = fname ? fname : _PATH_UTMPX;
122 if (stat(sfname, &st) == -1) {
123 warn("Cannot stat `%s'", sfname);
124 what &= ~1;
125 } else {
126 if (timespeccmp(&st.st_mtim, &utmpxtime, >))
127 utmpxtime = st.st_mtim;
128 else
129 what &= ~1;
130 }
131 }
132#endif
133#ifdef SUPPORT_UTMP
134 if (what & 2) {
135 sfname = fname ? fname : _PATH_UTMP;
136 if (stat(sfname, &st) == -1) {
137 warn("Cannot stat `%s'", sfname);
138 what &= ~2;
139 } else {
140 if (timespeccmp(&st.st_mtim, &utmptime, >))
141 utmptime = st.st_mtim;
142 else
143 what &= ~2;
144 }
145 }
146#endif
147 return what;
148}
149#endif
150
151void
152endutentries(void)
153{
154 struct utmpentry *ep;
155
156#ifdef SUPPORT_UTMP
157 timespecclear(&utmptime);
158#endif
159#ifdef SUPPORT_UTMPX
160 timespecclear(&utmpxtime);
161#endif
162 ep = ehead;
163 while (ep) {
164 struct utmpentry *sep = ep;
165 ep = ep->next;
166 free(sep);
167 }
168 ehead = NULL;
169 numutmp = 0;
170}
171
172size_t
173getutentries(const char *fname, struct utmpentry **epp)
174{
175#ifdef SUPPORT_UTMPX
176 struct utmpx *utx;
177#endif
178#ifdef SUPPORT_UTMP
179 struct utmp *ut;
180#endif
181#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
182 struct utmpentry *ep;
183 int what = setup(fname);
184 struct utmpentry **nextp = &ehead;
185 switch (what) {
186 case 0:
187 /* No updates */
188 *epp = ehead;
189 return numutmp;
190 default:
191 /* Need to re-scan */
192 ehead = NULL;
193 numutmp = 0;
194 }
195#endif
196
197#ifdef SUPPORT_UTMPX
198 setutxent();
199 while ((what & 1) && (utx = getutxent()) != NULL) {
200 if (fname == NULL && ((1 << utx->ut_type) & etype) == 0)
201 continue;
202 if ((ep = calloc(1, sizeof(*ep))) == NULL) {
203 warn(NULL);
204 return 0;
205 }
206 getentryx(ep, utx);
207 *nextp = ep;
208 nextp = &(ep->next);
209 }
210#endif
211
212#ifdef SUPPORT_UTMP
213 setutent();
214 if ((etype & (1 << USER_PROCESS)) != 0) {
215 while ((what & 2) && (ut = getutent()) != NULL) {
216 if (fname == NULL && (*ut->ut_name == '\0' ||
217 *ut->ut_line == '\0'))
218 continue;
219 /* Don't process entries that we have utmpx for */
220 for (ep = ehead; ep != NULL; ep = ep->next) {
221 if (strncmp(ep->line, ut->ut_line,
222 sizeof(ut->ut_line)) == 0)
223 break;
224 }
225 if (ep != NULL)
226 continue;
227 if ((ep = calloc(1, sizeof(*ep))) == NULL) {
228 warn(NULL);
229 return 0;
230 }
231 getentry(ep, ut);
232 *nextp = ep;
233 nextp = &(ep->next);
234 }
235 }
236#endif
237 numutmp = 0;
238#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
239 if (ehead != NULL) {
240 struct utmpentry *from = ehead, *save;
241
242 ehead = NULL;
243 while (from != NULL) {
244 for (nextp = &ehead;
245 (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
246 nextp = &(*nextp)->next)
247 continue;
248 save = from;
249 from = from->next;
250 save->next = *nextp;
251 *nextp = save;
252 numutmp++;
253 }
254 }
255 *epp = ehead;
256 return numutmp;
257#else
258 *epp = NULL;
259 return 0;
260#endif
261}
262
263#ifdef SUPPORT_UTMP
264static void
265getentry(struct utmpentry *e, struct utmp *up)
266{
267 COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
268 COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
269 COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
270
271 /*
272 * e has just been calloc'd. We don't need to clear it or
273 * append null-terminators, because its length is strictly
274 * greater than the source string. Use memcpy to read up->ut_*
275 * because they may not be terminated. For this reason we use
276 * the size of the source as the length argument.
277 */
278 memcpy(e->name, up->ut_name, sizeof(up->ut_name));
279 memcpy(e->line, up->ut_line, sizeof(up->ut_line));
280 memcpy(e->host, up->ut_host, sizeof(up->ut_host));
281
282 e->tv.tv_sec = up->ut_time;
283 e->tv.tv_usec = 0;
284 e->pid = 0;
285 e->term = 0;
286 e->exit = 0;
287 e->sess = 0;
288 e->type = USER_PROCESS;
289 adjust_size(e);
290}
291#endif
292
293#ifdef SUPPORT_UTMPX
294static void
295getentryx(struct utmpentry *e, struct utmpx *up)
296{
297 COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
298 COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
299 COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
300
301 /*
302 * e has just been calloc'd. We don't need to clear it or
303 * append null-terminators, because its length is strictly
304 * greater than the source string. Use memcpy to read up->ut_*
305 * because they may not be terminated. For this reason we use
306 * the size of the source as the length argument.
307 */
308 memcpy(e->name, up->ut_name, sizeof(up->ut_name));
309 memcpy(e->line, up->ut_line, sizeof(up->ut_line));
310 memcpy(e->host, up->ut_host, sizeof(up->ut_host));
311
312 e->tv = up->ut_tv;
313 e->pid = up->ut_pid;
314 e->term = up->ut_exit.e_termination;
315 e->exit = up->ut_exit.e_exit;
316 e->sess = up->ut_session;
317 e->type = up->ut_type;
318 adjust_size(e);
319}
320#endif
