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 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <sys/types.h>
33 #include <sys/sysi86.h>
34 #include <errno.h>
35 #include <time.h>
36 #include <string.h>
37 #include <sys/stat.h>
38
39 static char *progname;
40 static char *zonefile = "/etc/rtc_config";
41 static FILE *zonefptr;
42 static char zone_info[256];
43 static char zone_lag[256];
44 static char tz[256] = "TZ=";
45 int debug = 0;
46 int lag;
47 int errors_ok = 0; /* allow "rtc no-args" to be quiet when not configured */
48 static time_t clock_val;
49 static char zone_comment[] =
50 "#\n"
51 "# This file (%s) contains information used to manage the\n"
52 "# x86 real time clock hardware. The hardware is kept in\n"
53 "# the machine's local time for compatibility with other x86\n"
54 "# operating systems. This file is read by the kernel at\n"
55 "# boot time. It is set and updated by the /usr/sbin/rtc\n"
56 "# command. The 'zone_info' field designates the local\n"
57 "# time zone. The 'zone_lag' field indicates the number\n"
58 "# of seconds between local time and Greenwich Mean Time.\n"
59 "#\n";
60
61 /*
62 * Open the configuration file and extract the
63 * zone_info and the zone_lag. Return 0 if successful.
64 */
65 int
66 open_zonefile()
67 {
68 char b[256], *s;
69 int lag_hrs;
70
71 if ((zonefptr = fopen(zonefile, "r")) == NULL) {
72 if (errors_ok == 0)
73 (void) fprintf(stderr,
74 "%s: cannot open %s: errno = %d\n",
75 progname, zonefile, errno);
76 return (1);
77 }
78
79 for (;;) {
80 if ((s = fgets(b, sizeof (b), zonefptr)) == NULL)
81 break;
82 if ((s = strchr(s, 'z')) == NULL)
83 continue;
84 if (strncmp(s, "zone_info", 9) == 0) {
85 s += 9;
86 while (*s != 0 && *s != '=')
87 s++;
88 if (*s == '=') {
89 s++;
90 while (*s != 0 && (*s == ' ' || *s == '\t'))
91 s++;
92 (void) strncpy(zone_info, s,
93 sizeof (zone_info));
94 s = zone_info;
95 while (*s != 0 && *s != '\n')
96 s++;
97 if (*s == '\n')
98 *s = 0;
99 }
100 } else if (strncmp(s, "zone_lag", 8) == 0) {
101 s += 8;
102 while (*s != 0 && *s != '=')
103 s++;
104 if (*s == '=') {
105 s++;
106 while (*s != 0 && (*s == ' ' || *s == '\t'))
107 s++;
108 (void) strncpy(zone_lag, s, sizeof (zone_lag));
109 s = zone_lag;
110 while (*s != 0 && *s != '\n')
111 s++;
112 if (*s == '\n')
113 *s = 0;
114 }
115 }
116 }
117 lag = atoi(zone_lag);
118 lag_hrs = lag / 3600;
119 if (zone_info[0] == 0) {
120 (void) fprintf(stderr, "%s: zone_info field is invalid\n",
121 progname);
122 zone_info[0] = 0;
123 zone_lag[0] = 0;
124 return (1);
125 }
126 if (zone_lag[0] == 0) {
127 (void) fprintf(stderr, "%s: zone_lag field is invalid\n",
128 progname);
129 zone_lag[0] = 0;
130 return (1);
131 }
132 if ((lag_hrs < -24) || (lag_hrs > 24)) {
133 (void) fprintf(stderr, "%s: a GMT lag of %d is out of range\n",
134 progname, lag_hrs);
135 zone_info[0] = 0;
136 zone_lag[0] = 0;
137 return (1);
138 }
139 if (debug)
140 (void) fprintf(stderr, "zone_info = %s, zone_lag = %s\n",
141 zone_info, zone_lag);
142 if (debug)
143 (void) fprintf(stderr, "lag (decimal) is %d\n", lag);
144
145 (void) fclose(zonefptr);
146 zonefptr = NULL;
147 return (0);
148 }
149
150 void
151 display_zone_string(void)
152 {
153 if (open_zonefile() == 0)
154 (void) printf("%s\n", zone_info);
155 else
156 (void) printf("GMT\n");
157 }
158
159 long
160 set_zone(char *zone_string)
161 {
162 struct tm *tm;
163 long current_lag;
164
165 (void) umask(0022);
166 if ((zonefptr = fopen(zonefile, "w")) == NULL) {
167 (void) fprintf(stderr, "%s: cannot open %s: errno = %d\n",
168 progname, zonefile, errno);
169 return (0);
170 }
171
172 tz[3] = 0;
173 (void) strncat(tz, zone_string, 253);
174 if (debug)
175 (void) fprintf(stderr, "Time Zone string is '%s'\n", tz);
176
177 (void) putenv(tz);
178 if (debug)
179 (void) system("env | grep TZ");
180
181 (void) time(&clock_val);
182
183 tm = localtime(&clock_val);
184 current_lag = tm->tm_isdst ? altzone : timezone;
185 if (debug)
186 (void) printf("%s DST. Lag is %ld.\n", tm->tm_isdst ? "Is" :
187 "Is NOT", tm->tm_isdst ? altzone : timezone);
188
189 (void) fprintf(zonefptr, zone_comment, zonefile);
190 (void) fprintf(zonefptr, "zone_info=%s\n", zone_string);
191 (void) fprintf(zonefptr, "zone_lag=%ld\n",
192 tm->tm_isdst ? altzone : timezone);
193 (void) fclose(zonefptr);
194 zonefptr = NULL;
195 return (current_lag);
196 }
197
198 void
199 correct_rtc_and_lag()
200 {
201 struct tm *tm;
202 long kernels_lag;
203 long current_lag;
204
205 if (open_zonefile())
206 return;
207
208 tz[3] = 0;
209 (void) strncat(tz, zone_info, 253);
210 if (debug)
211 (void) fprintf(stderr, "Time Zone string is '%s'\n", tz);
212
213 (void) putenv(tz);
214 if (debug)
215 (void) system("env | grep TZ");
216
217 (void) time(&clock_val);
218 tm = localtime(&clock_val);
219 current_lag = tm->tm_isdst ? altzone : timezone;
220
221 if (current_lag != lag) { /* if file is wrong */
222 if (debug)
223 (void) fprintf(stderr, "correcting file");
224 (void) set_zone(zone_info); /* then rewrite file */
225 }
226
227 (void) sysi86(GGMTL, &kernels_lag);
228 if (current_lag != kernels_lag) {
229 if (debug)
230 (void) fprintf(stderr, "correcting kernel's lag");
231 (void) sysi86(SGMTL, current_lag); /* correct the lag */
232 (void) sysi86(WTODC); /* set the rtc to */
233 /* new local time */
234 }
235 }
236
237 void
238 initialize_zone(char *zone_string)
239 {
240 long current_lag;
241
242 /* write the config file */
243 current_lag = set_zone(zone_string);
244
245 /* correct the lag */
246 (void) sysi86(SGMTL, current_lag);
247
248 /*
249 * set the unix time from the rtc,
250 * assuming the rtc was the correct
251 * local time.
252 */
253 (void) sysi86(RTCSYNC);
254 }
255
256 void
257 usage()
258 {
259 static char Usage[] = "Usage:\n\
260 rtc [-c] [-z time_zone] [-?]\n";
261
262 (void) fprintf(stderr, Usage);
263 }
264
265 void
266 verbose_usage()
267 {
268 static char Usage1[] = "\
269 Options:\n\
270 -c\t\tCheck and correct for daylight savings time rollover.\n\
271 -z [zone]\tRecord the zone info in the config file.\n";
272
273 (void) fprintf(stderr, Usage1);
274 }
275
276 int
277 main(int argc, char *argv[])
278 {
279 int c;
280
281 progname = argv[0];
282
283 if (argc == 1) {
284 errors_ok = 1;
285 display_zone_string();
286 }
287
288 while ((c = getopt(argc, argv, "cz:d")) != EOF) {
289 switch (c) {
290 case 'c':
291 correct_rtc_and_lag();
292 continue;
293 case 'z':
294 initialize_zone(optarg);
295 continue;
296 case 'd':
297 debug = 1;
298 continue;
299 case '?':
300 verbose_usage();
301 return (0);
302 default:
303 usage();
304 return (1);
305 }
306 }
307 return (0);
308 }