1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2018 Gary Mills
24 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
25 * Use is subject to license terms.
26 */
27
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <unistd.h>
31 #include <sys/types.h>
32 #include <sys/sysi86.h>
33 #include <errno.h>
34 #include <time.h>
35 #include <string.h>
36 #include <sys/stat.h>
37
38 /* RTC modes */
39 #define M_UNSET 0 /* Mode never set */
40 #define M_VAR 1 /* Tracks local time including DST */
41 #define M_UTC 2 /* Clock runs in UTC */
42 #define M_STD 3 /* Clock runs in local standard time */
43
44 static char *progname;
45 static char *zonefile = "/etc/rtc_config";
46 static FILE *zonefptr;
47 static char zone_info[256];
48 static char zone_lag[256];
49 static char tz[256] = "TZ=";
50 static char *utc_zone = "UTC";
51 int debug = 0;
52 int rtc_mode = M_UNSET;
53 int lag;
54 int errors_ok = 0; /* allow "rtc no-args" to be quiet when not configured */
55 static time_t clock_val;
56 static char zone_comment[] =
57 "#\n"
58 "# This file (%s) contains information used to manage the\n"
59 "# x86 real time clock hardware. The hardware is kept in\n"
60 "# the machine's local time for compatibility with other x86\n"
61 "# operating systems. This file is read by the kernel at\n"
62 "# boot time. It is set and updated by the /usr/sbin/rtc\n"
63 "# command. The 'zone_info' field designates the local\n"
64 "# time zone. The 'zone_lag' field indicates the number\n"
65 "# of seconds between local time and Greenwich Mean Time.\n"
66 "#\n";
67
68 /*
69 * Open the configuration file and extract the
70 * zone_info and the zone_lag. Return 0 if successful.
71 */
72 int
73 open_zonefile()
74 {
75 char b[256], *s;
76 int lag_hrs;
77
78 if ((zonefptr = fopen(zonefile, "r")) == NULL) {
79 if (errors_ok == 0)
80 (void) fprintf(stderr,
81 "%s: cannot open %s: errno = %d\n",
82 progname, zonefile, errno);
83 return (1);
84 }
85
86 for (;;) {
87 if ((s = fgets(b, sizeof (b), zonefptr)) == NULL)
88 break;
89 if ((s = strchr(s, 'z')) == NULL)
90 continue;
91 if (strncmp(s, "zone_info", 9) == 0) {
92 s += 9;
93 while (*s != 0 && *s != '=')
94 s++;
95 if (*s == '=') {
96 s++;
97 while (*s != 0 && (*s == ' ' || *s == '\t'))
98 s++;
99 (void) strncpy(zone_info, s,
100 sizeof (zone_info));
101 s = zone_info;
102 while (*s != 0 && *s != '\n')
103 s++;
104 if (*s == '\n')
105 *s = 0;
106 }
107 } else if (strncmp(s, "zone_lag", 8) == 0) {
108 s += 8;
109 while (*s != 0 && *s != '=')
110 s++;
111 if (*s == '=') {
112 s++;
113 while (*s != 0 && (*s == ' ' || *s == '\t'))
114 s++;
115 (void) strncpy(zone_lag, s, sizeof (zone_lag));
116 s = zone_lag;
117 while (*s != 0 && *s != '\n')
118 s++;
119 if (*s == '\n')
120 *s = 0;
121 }
122 }
123 }
124 lag = atoi(zone_lag);
125 lag_hrs = lag / 3600;
126 if (zone_info[0] == 0) {
127 (void) fprintf(stderr, "%s: zone_info field is invalid\n",
128 progname);
129 zone_info[0] = 0;
130 zone_lag[0] = 0;
131 return (1);
132 }
133 if (zone_lag[0] == 0) {
134 (void) fprintf(stderr, "%s: zone_lag field is invalid\n",
135 progname);
136 zone_lag[0] = 0;
137 return (1);
138 }
139 if ((lag_hrs < -24) || (lag_hrs > 24)) {
140 (void) fprintf(stderr, "%s: a GMT lag of %d is out of range\n",
141 progname, lag_hrs);
142 zone_info[0] = 0;
143 zone_lag[0] = 0;
144 return (1);
145 }
146 if (debug)
147 (void) fprintf(stderr, "zone_info = %s, zone_lag = %s\n",
148 zone_info, zone_lag);
149 if (debug)
150 (void) fprintf(stderr, "lag (decimal) is %d\n", lag);
151
152 (void) fclose(zonefptr);
153 zonefptr = NULL;
154 return (0);
155 }
156
157 void
158 display_zone_string(void)
159 {
160 if (open_zonefile() == 0)
161 (void) printf("%s\n", zone_info);
162 else
163 (void) printf("GMT\n");
164 }
165
166 int
167 get_local(char *z)
168 {
169 struct tm *tm;
170
171 tz[3] = 0;
172 (void) strncat(tz, z, 253);
173 if (debug)
174 (void) fprintf(stderr, "Time Zone string is '%s'\n", tz);
175
176 (void) putenv(tz);
177 if (debug)
178 (void) system("env | grep TZ");
179
180 (void) time(&clock_val);
181
182 tm = localtime(&clock_val);
183 return (tm->tm_isdst);
184 }
185
186 long
187 set_zone(char *zone_string)
188 {
189 int isdst;
190 long current_lag;
191
192 (void) umask(0022);
193 if ((zonefptr = fopen(zonefile, "w")) == NULL) {
194 (void) fprintf(stderr, "%s: cannot open %s: errno = %d\n",
195 progname, zonefile, errno);
196 return (0);
197 }
198
199 switch (rtc_mode) {
200 case M_VAR:
201 isdst = get_local(zone_string);
202 current_lag = isdst ? altzone : timezone;
203 break;
204 case M_STD:
205 isdst = get_local(zone_string);
206 current_lag = timezone;
207 break;
208 default: /* Includes M_UTC */
209 isdst = 0;
210 current_lag = 0;
211 zone_string = utc_zone;
212 break;
213 }
214 if (debug)
215 (void) printf("%s DST. Lag is %ld.\n", isdst ? "Is" :
216 "Is NOT", current_lag);
217
218 (void) fprintf(zonefptr, zone_comment, zonefile);
219 (void) fprintf(zonefptr, "zone_info=%s\n", zone_string);
220 (void) fprintf(zonefptr, "zone_lag=%ld\n", current_lag);
221 (void) fclose(zonefptr);
222 zonefptr = NULL;
223 return (current_lag);
224 }
225
226 void
227 correct_rtc_and_lag()
228 {
229 int isdst;
230 long kernels_lag;
231 long current_lag;
232
233 if (open_zonefile())
234 return;
235
236 switch (rtc_mode) {
237 case M_VAR:
238 isdst = get_local(zone_info);
239 current_lag = isdst ? altzone : timezone;
240 break;
241 case M_STD:
242 (void) get_local(zone_info);
243 current_lag = timezone;
244 break;
245 default: /* Includes M_UTC */
246 current_lag = 0;
247 break;
248 }
249
250 if (current_lag != lag) { /* if file is wrong */
251 if (debug)
252 (void) fprintf(stderr, "correcting file\n");
253 (void) set_zone(zone_info); /* then rewrite file */
254 }
255
256 (void) sysi86(GGMTL, &kernels_lag);
257 if (current_lag != kernels_lag) {
258 if (debug)
259 (void) fprintf(stderr, "correcting kernel's lag\n");
260 (void) sysi86(SGMTL, current_lag); /* correct the lag */
261 (void) sysi86(WTODC); /* set the rtc to */
262 /* new local time */
263 }
264 }
265
266 void
267 initialize_zone(char *zone_string)
268 {
269 long current_lag;
270
271 /* write the config file */
272 current_lag = set_zone(zone_string);
273
274 /* correct the lag */
275 (void) sysi86(SGMTL, current_lag);
276
277 /*
278 * set the unix time from the rtc,
279 * assuming the rtc was the correct
280 * local time.
281 */
282 (void) sysi86(RTCSYNC);
283 }
284
285 void
286 usage()
287 {
288 static char Usage[] = "Usage:\n\
289 rtc [-w] [-s|-u|-v] [-c] [-z time_zone] [-?]\n";
290
291 (void) fprintf(stderr, Usage);
292 }
293
294 void
295 verbose_usage()
296 {
297 static char Usage1[] = "\
298 Options:\n\
299 -w\t\tDoes nothing.\n\
300 -s\t\tRTC runs in local standard time.\n\
301 -u\t\tRTC runs in UTC time.\n\
302 -v\t\tRTC tracks local time (with cron command).\n\
303 -c\t\tCheck and correct for daylight savings time rollover.\n\
304 -z [zone]\tRecord the zone info in the config file.\n";
305
306 (void) fprintf(stderr, Usage1);
307 }
308
309 void
310 set_default()
311 {
312 switch (rtc_mode) {
313 default: /* Includes M_UNSET */
314 rtc_mode = M_VAR;
315 break;
316 case M_VAR:
317 /*FALLTHROUGH*/
318 case M_UTC:
319 /*FALLTHROUGH*/
320 case M_STD:
321 break;
322 }
323 }
324
325 void
326 check_mode(int letter, int mode)
327 {
328 if (rtc_mode == M_UNSET || rtc_mode == mode) {
329 rtc_mode = mode;
330 return;
331 }
332 (void) fprintf(stderr, "%s: option -%c conflicts with other options\n",
333 progname, letter);
334 exit(1);
335 }
336
337
338 int
339 main(int argc, char *argv[])
340 {
341 int c;
342 int cflg = 0;
343 char *zone_name = NULL;
344
345 progname = argv[0];
346
347 if (argc == 1) {
348 errors_ok = 1;
349 display_zone_string();
350 exit(0);
351 }
352
353 while ((c = getopt(argc, argv, "suvwcz:d")) != EOF) {
354 switch (c) {
355 case 'c':
356 cflg++;
357 continue;
358 case 'z':
359 zone_name = optarg;
360 continue;
361 case 'd':
362 debug = 1;
363 continue;
364 case 's': /* standard: RTC runs local standard time */
365 check_mode(c, M_STD);
366 continue;
367 case 'u': /* utc: RTC runs UTC time */
368 check_mode(c, M_UTC);
369 continue;
370 case 'v': /* varies: RTC tracks local time */
371 check_mode(c, M_VAR);
372 continue;
373 case 'w': /* Does nothing */
374 continue;
375 case '?':
376 verbose_usage();
377 exit(0);
378 default:
379 usage();
380 exit(1);
381 }
382 }
383 set_default();
384 if (zone_name != NULL)
385 initialize_zone(zone_name);
386 if (cflg > 0)
387 correct_rtc_and_lag();
388 exit(0);
389 /*LINTED*/
390 }