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 /* 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
60 static void getentry(struct utmpentry *, struct utmp *);
61 static struct timespec utmptime = {0, 0};
62 #endif
63 #ifdef SUPPORT_UTMPX
64 static void getentryx(struct utmpentry *, struct utmpx *);
65 static struct timespec utmpxtime = {0, 0};
66 #endif
67 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
68 static int setup(const char *);
69 static void adjust_size(struct utmpentry *e);
70 #endif
71
72 size_t maxname = 8, maxline = 8, maxhost = 16;
73 int etype = 1 << USER_PROCESS;
74 static size_t numutmp = 0;
75 static struct utmpentry *ehead;
76
77 #if defined(SUPPORT_UTMPX) || defined(SUPPORT_UTMP)
78 static void
adjust_size(struct utmpentry * e)79 adjust_size(struct utmpentry *e)
80 {
81 size_t 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
91 static int
setup(const char * fname)92 setup(const char *fname)
93 {
94 int what = 3;
95 struct stat st;
96 const char *sfname;
97
98 if (fname != NULL) {
99 size_t len = strlen(fname);
100 if (len == 0)
101 errx(1, "Filename cannot be 0 length.");
102 what = fname[len - 1] == 'x' ? 1 : 2;
103 if (what == 1) {
104 #ifdef SUPPORT_UTMPX
105 if (utmpxname(fname) == 0)
106 warnx("Cannot set utmpx file to `%s'",
107 fname);
108 #else
109 warnx("utmpx support not compiled in");
110 #endif
111 } else {
112 #ifdef SUPPORT_UTMP
113 if (utmpname(fname) == 0)
114 warnx("Cannot set utmp file to `%s'",
115 fname);
116 #else
117 warnx("utmp support not compiled in");
118 #endif
119 }
120 }
121 #ifdef SUPPORT_UTMPX
122 if (what & 1) {
123 sfname = fname ? fname : _PATH_UTMPX;
124 if (stat(sfname, &st) == -1) {
125 warn("Cannot stat `%s'", sfname);
126 what &= ~1;
127 } else {
128 if (timespeccmp(&st.st_mtimespec, &utmpxtime, >))
129 utmpxtime = st.st_mtimespec;
130 else
131 what &= ~1;
132 }
133 }
134 #endif
135 #ifdef SUPPORT_UTMP
136 if (what & 2) {
137 sfname = fname ? fname : _PATH_UTMP;
138 if (stat(sfname, &st) == -1) {
139 warn("Cannot stat `%s'", sfname);
140 what &= ~2;
141 } else {
142 if (timespeccmp(&st.st_mtimespec, &utmptime, >))
143 utmptime = st.st_mtimespec;
144 else
145 what &= ~2;
146 }
147 }
148 #endif
149 return what;
150 }
151 #endif
152
153 void
endutentries(void)154 endutentries(void)
155 {
156 struct utmpentry *ep;
157
158 #ifdef SUPPORT_UTMP
159 timespecclear(&utmptime);
160 #endif
161 #ifdef SUPPORT_UTMPX
162 timespecclear(&utmpxtime);
163 #endif
164 ep = ehead;
165 while (ep) {
166 struct utmpentry *sep = ep;
167 ep = ep->next;
168 free(sep);
169 }
170 ehead = NULL;
171 numutmp = 0;
172 }
173
174 size_t
getutentries(const char * fname,struct utmpentry ** epp)175 getutentries(const char *fname, struct utmpentry **epp)
176 {
177 #ifdef SUPPORT_UTMPX
178 struct utmpx *utx;
179 #endif
180 #ifdef SUPPORT_UTMP
181 struct utmp *ut;
182 #endif
183 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
184 struct utmpentry *ep;
185 int what = setup(fname);
186 struct utmpentry **nextp = &ehead;
187 switch (what) {
188 case 0:
189 /* No updates */
190 *epp = ehead;
191 return numutmp;
192 default:
193 /* Need to re-scan */
194 ehead = NULL;
195 numutmp = 0;
196 }
197 #endif
198
199 #ifdef SUPPORT_UTMPX
200 setutxent();
201 while ((what & 1) && (utx = getutxent()) != NULL) {
202 if (fname == NULL && ((1 << utx->ut_type) & etype) == 0)
203 continue;
204 if ((ep = calloc(1, sizeof(*ep))) == NULL) {
205 warn(NULL);
206 return 0;
207 }
208 getentryx(ep, utx);
209 *nextp = ep;
210 nextp = &(ep->next);
211 }
212 #endif
213
214 #ifdef SUPPORT_UTMP
215 setutent();
216 if ((etype & (1 << USER_PROCESS)) != 0) {
217 while ((what & 2) && (ut = getutent()) != NULL) {
218 if (fname == NULL && (*ut->ut_name == '\0' ||
219 *ut->ut_line == '\0'))
220 continue;
221 /* Don't process entries that we have utmpx for */
222 for (ep = ehead; ep != NULL; ep = ep->next) {
223 if (strncmp(ep->line, ut->ut_line,
224 sizeof(ut->ut_line)) == 0)
225 break;
226 }
227 if (ep != NULL)
228 continue;
229 if ((ep = calloc(1, sizeof(*ep))) == NULL) {
230 warn(NULL);
231 return 0;
232 }
233 getentry(ep, ut);
234 *nextp = ep;
235 nextp = &(ep->next);
236 }
237 }
238 #endif
239 numutmp = 0;
240 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
241 if (ehead != NULL) {
242 struct utmpentry *from = ehead, *save;
243
244 ehead = NULL;
245 while (from != NULL) {
246 for (nextp = &ehead;
247 (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
248 nextp = &(*nextp)->next)
249 continue;
250 save = from;
251 from = from->next;
252 save->next = *nextp;
253 *nextp = save;
254 numutmp++;
255 }
256 }
257 *epp = ehead;
258 return numutmp;
259 #else
260 *epp = NULL;
261 return 0;
262 #endif
263 }
264
265 #ifdef SUPPORT_UTMP
266 static void
getentry(struct utmpentry * e,struct utmp * up)267 getentry(struct utmpentry *e, struct utmp *up)
268 {
269 COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
270 COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
271 COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
272
273 /*
274 * e has just been calloc'd. We don't need to clear it or
275 * append null-terminators, because its length is strictly
276 * greater than the source string. Use memcpy to _read_
277 * up->ut_* because they may not be terminated. For this
278 * reason we use the size of the _source_ as the length
279 * argument.
280 */
281 memcpy(e->name, up->ut_name, sizeof(up->ut_name));
282 memcpy(e->line, up->ut_line, sizeof(up->ut_line));
283 memcpy(e->host, up->ut_host, sizeof(up->ut_host));
284
285 e->tv.tv_sec = up->ut_time;
286 e->tv.tv_usec = 0;
287 e->pid = 0;
288 e->term = 0;
289 e->exit = 0;
290 e->sess = 0;
291 e->type = USER_PROCESS;
292 adjust_size(e);
293 }
294 #endif
295
296 #ifdef SUPPORT_UTMPX
297 static void
getentryx(struct utmpentry * e,struct utmpx * up)298 getentryx(struct utmpentry *e, struct utmpx *up)
299 {
300 COMPILE_ASSERT(sizeof(e->name) > sizeof(up->ut_name));
301 COMPILE_ASSERT(sizeof(e->line) > sizeof(up->ut_line));
302 COMPILE_ASSERT(sizeof(e->host) > sizeof(up->ut_host));
303
304 /*
305 * e has just been calloc'd. We don't need to clear it or
306 * append null-terminators, because its length is strictly
307 * greater than the source string. Use memcpy to _read_
308 * up->ut_* because they may not be terminated. For this
309 * reason we use the size of the _source_ as the length
310 * argument.
311 */
312 memcpy(e->name, up->ut_name, sizeof(up->ut_name));
313 memcpy(e->line, up->ut_line, sizeof(up->ut_line));
314 memcpy(e->host, up->ut_host, sizeof(up->ut_host));
315
316 e->tv = up->ut_tv;
317 e->pid = up->ut_pid;
318 e->term = up->ut_exit.e_termination;
319 e->exit = up->ut_exit.e_exit;
320 e->sess = up->ut_session;
321 e->type = up->ut_type;
322 adjust_size(e);
323 }
324 #endif
325