usr/src/cmd/rtc/rtc.c

   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 }