time/zdump.c

   1 #ifdef  LIBC
   2 #include <ansidecl.h>
   3 #endif
   4
   5 #ifndef lint
   6 #ifndef NOID
   7 static char     elsieid[] = "@(#)zdump.c        7.2";
   8 #endif /* !defined NOID */
   9 #endif /* !defined lint */
  10
  11 /*
  12 ** This code has been made independent of the rest of the time
  13 ** conversion package to increase confidence in the verification it provides.
  14 ** You can use this code to help in verifying other implementations.
  15 */
  16
  17 #include "stdio.h"      /* for stdout, stderr */
  18 #include "string.h"     /* for strcpy */
  19 #include "sys/types.h"  /* for time_t */
  20 #include "time.h"       /* for struct tm */
  21
  22 #ifndef MAX_STRING_LENGTH
  23 #define MAX_STRING_LENGTH       1024
  24 #endif /* !defined MAX_STRING_LENGTH */
  25
  26 #ifndef TRUE
  27 #define TRUE            1
  28 #endif /* !defined TRUE */
  29
  30 #ifndef FALSE
  31 #define FALSE           0
  32 #endif /* !defined FALSE */
  33
  34 #ifndef EXIT_SUCCESS
  35 #define EXIT_SUCCESS    0
  36 #endif /* !defined EXIT_SUCCESS */
  37
  38 #ifndef EXIT_FAILURE
  39 #define EXIT_FAILURE    1
  40 #endif /* !defined EXIT_FAILURE */
  41
  42 #ifndef SECSPERMIN
  43 #define SECSPERMIN      60
  44 #endif /* !defined SECSPERMIN */
  45
  46 #ifndef SECSPERHOUR
  47 #define SECSPERHOUR     3600
  48 #endif /* !defined SECSPERHOUR */
  49
  50 #ifndef HOURSPERDAY
  51 #define HOURSPERDAY     24
  52 #endif /* !defined HOURSPERDAY */
  53
  54 #ifndef EPOCH_YEAR
  55 #define EPOCH_YEAR      1970
  56 #endif /* !defined EPOCH_YEAR */
  57
  58 #ifndef DAYSPERNYEAR
  59 #define DAYSPERNYEAR    365
  60 #endif /* !defined DAYSPERNYEAR */
  61
  62 extern char **  environ;
  63 extern int      getopt();
  64 extern char *   optarg;
  65 extern int      optind;
  66 extern time_t   time();
  67 extern char *   tzname[2];
  68 extern void     tzset();
  69
  70 #ifdef USG
  71 extern void     exit();
  72 extern void     perror();
  73 #endif /* defined USG */
  74
  75 static char *   abbr();
  76 static long     delta();
  77 static void     hunt();
  78 static int      longest;
  79 static char *   progname;
  80 static void     show();
  81
  82 int
  83 main(argc, argv)
  84 int     argc;
  85 char *  argv[];
  86 {
  87         register int    i, c;
  88         register int    vflag;
  89         register char * cutoff;
  90         register int    cutyear;
  91         register long   cuttime;
  92         time_t          now;
  93         time_t          t, newt;
  94         time_t          hibit;
  95         struct tm       tm, newtm;
  96
  97         progname = argv[0];
  98         vflag = 0;
  99         cutoff = NULL;
 100         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 101                 if (c == 'v')
 102                         vflag = 1;
 103                 else    cutoff = optarg;
 104         if (c != EOF ||
 105            (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 106                 (void) fprintf(stderr,
 107                         "%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n",
 108                         argv[0], argv[0]);
 109                 (void) exit(EXIT_FAILURE);
 110         }
 111         if (cutoff != NULL)
 112                 cutyear = atoi(cutoff);
 113         /*
 114         ** VERY approximate.
 115         */
 116         cuttime = (long) (cutyear - EPOCH_YEAR) *
 117                 SECSPERHOUR * HOURSPERDAY * DAYSPERNYEAR;
 118         (void) time(&now);
 119         longest = 0;
 120         for (i = optind; i < argc; ++i)
 121                 if (strlen(argv[i]) > longest)
 122                         longest = strlen(argv[i]);
 123         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 124                 ;
 125         for (i = optind; i < argc; ++i) {
 126                 register char **        saveenv;
 127                 static char             buf[MAX_STRING_LENGTH];
 128                 char *                  fakeenv[2];
 129
 130                 if (strlen(argv[i]) + 4 > sizeof buf) {
 131                         (void) fflush(stdout);
 132                         (void) fprintf(stderr, "%s: argument too long -- %s\n",
 133                                 progname, argv[i]);
 134                         (void) exit(EXIT_FAILURE);
 135                 }
 136                 (void) strcpy(buf, "TZ=");
 137                 (void) strcat(buf, argv[i]);
 138                 fakeenv[0] = buf;
 139                 fakeenv[1] = NULL;
 140                 saveenv = environ;
 141                 environ = fakeenv;
 142                 (void) tzset();
 143                 environ = saveenv;
 144                 show(argv[i], now, FALSE);
 145                 if (!vflag)
 146                         continue;
 147                 /*
 148                 ** Get lowest value of t.
 149                 */
 150                 t = hibit;
 151                 if (t > 0)              /* time_t is unsigned */
 152                         t = 0;
 153                 show(argv[i], t, TRUE);
 154                 t += SECSPERHOUR * HOURSPERDAY;
 155                 show(argv[i], t, TRUE);
 156                 tm = *localtime(&t);
 157                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 158                 for ( ; ; ) {
 159                         if (cutoff != NULL && t >= cuttime)
 160                                 break;
 161                         newt = t + SECSPERHOUR * 12;
 162                         if (cutoff != NULL && newt >= cuttime)
 163                                 break;
 164                         if (newt <= t)
 165                                 break;
 166                         newtm = *localtime(&newt);
 167                         if (delta(&newtm, &tm) != (newt - t) ||
 168                                 newtm.tm_isdst != tm.tm_isdst ||
 169                                 strcmp(abbr(&newtm), buf) != 0) {
 170                                         hunt(argv[i], t, newt);
 171                                         (void) strncpy(buf, abbr(&newtm),
 172                                                 (sizeof buf) - 1);
 173                         }
 174                         t = newt;
 175                         tm = newtm;
 176                 }
 177                 /*
 178                 ** Get highest value of t.
 179                 */
 180                 t = ~((time_t) 0);
 181                 if (t < 0)              /* time_t is signed */
 182                         t &= ~hibit;
 183                 t -= SECSPERHOUR * HOURSPERDAY;
 184                 show(argv[i], t, TRUE);
 185                 t += SECSPERHOUR * HOURSPERDAY;
 186                 show(argv[i], t, TRUE);
 187         }
 188         if (fflush(stdout) || ferror(stdout)) {
 189                 (void) fprintf(stderr, "%s: Error writing standard output ",
 190                         argv[0]);
 191                 (void) perror("standard output");
 192                 (void) exit(EXIT_FAILURE);
 193         }
 194         exit(EXIT_SUCCESS);
 195
 196         /* gcc -Wall pacifier */
 197         for ( ; ; )
 198                 ;
 199 }
 200
 201 static void
 202 hunt(name, lot, hit)
 203 char *  name;
 204 time_t  lot;
 205 time_t  hit;
 206 {
 207         time_t          t;
 208         struct tm       lotm;
 209         struct tm       tm;
 210         static char     loab[MAX_STRING_LENGTH];
 211
 212         lotm = *localtime(&lot);
 213         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 214         while ((hit - lot) >= 2) {
 215                 t = lot / 2 + hit / 2;
 216                 if (t <= lot)
 217                         ++t;
 218                 else if (t >= hit)
 219                         --t;
 220                 tm = *localtime(&t);
 221                 if (delta(&tm, &lotm) == (t - lot) &&
 222                         tm.tm_isdst == lotm.tm_isdst &&
 223                         strcmp(abbr(&tm), loab) == 0) {
 224                                 lot = t;
 225                                 lotm = tm;
 226                 } else  hit = t;
 227         }
 228         show(name, lot, TRUE);
 229         show(name, hit, TRUE);
 230 }
 231
 232 static long
 233 delta(newp, oldp)
 234 struct tm *     newp;
 235 struct tm *     oldp;
 236 {
 237         long    result;
 238
 239         result = newp->tm_hour - oldp->tm_hour;
 240         if (result < 0)
 241                 result += HOURSPERDAY;
 242         result *= SECSPERHOUR;
 243         result += (newp->tm_min - oldp->tm_min) * SECSPERMIN;
 244         return result + newp->tm_sec - oldp->tm_sec;
 245 }
 246
 247 static void
 248 show(zone, t, v)
 249 char *  zone;
 250 time_t  t;
 251 int     v;
 252 {
 253         struct tm *             tmp;
 254         extern struct tm *      localtime();
 255
 256         (void) printf("%-*s  ", longest, zone);
 257         if (v)
 258                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
 259         tmp = localtime(&t);
 260         (void) printf("%.24s", asctime(tmp));
 261         if (*abbr(tmp) != '\0')
 262                 (void) printf(" %s", abbr(tmp));
 263         if (v) {
 264                 (void) printf(" isdst=%d", tmp->tm_isdst);
 265 #ifdef TM_GMTOFF
 266                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 267 #endif /* defined TM_GMTOFF */
 268         }
 269         (void) printf("\n");
 270 }
 271
 272 static char *
 273 abbr(tmp)
 274 struct tm *     tmp;
 275 {
 276         register char * result;
 277
 278         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 279                 return "";
 280         result = tzname[tmp->tm_isdst];
 281         return (result == NULL) ? "" : result;
 282 }