timezone/zdump.c

   1 static char     elsieid[] = "@(#)zdump.c        7.31";
   2
   3 /*
   4 ** This code has been made independent of the rest of the time
   5 ** conversion package to increase confidence in the verification it provides.
   6 ** You can use this code to help in verifying other implementations.
   7 */
   8
   9 #include "stdio.h"      /* for stdout, stderr, perror */
  10 #include "string.h"     /* for strcpy */
  11 #include "sys/types.h"  /* for time_t */
  12 #include "time.h"       /* for struct tm */
  13 #include "stdlib.h"     /* for exit, malloc, atoi */
  14
  15 #ifndef MAX_STRING_LENGTH
  16 #define MAX_STRING_LENGTH       1024
  17 #endif /* !defined MAX_STRING_LENGTH */
  18
  19 #ifndef TRUE
  20 #define TRUE            1
  21 #endif /* !defined TRUE */
  22
  23 #ifndef FALSE
  24 #define FALSE           0
  25 #endif /* !defined FALSE */
  26
  27 #ifndef EXIT_SUCCESS
  28 #define EXIT_SUCCESS    0
  29 #endif /* !defined EXIT_SUCCESS */
  30
  31 #ifndef EXIT_FAILURE
  32 #define EXIT_FAILURE    1
  33 #endif /* !defined EXIT_FAILURE */
  34
  35 #ifndef SECSPERMIN
  36 #define SECSPERMIN      60
  37 #endif /* !defined SECSPERMIN */
  38
  39 #ifndef MINSPERHOUR
  40 #define MINSPERHOUR     60
  41 #endif /* !defined MINSPERHOUR */
  42
  43 #ifndef SECSPERHOUR
  44 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
  45 #endif /* !defined SECSPERHOUR */
  46
  47 #ifndef HOURSPERDAY
  48 #define HOURSPERDAY     24
  49 #endif /* !defined HOURSPERDAY */
  50
  51 #ifndef EPOCH_YEAR
  52 #define EPOCH_YEAR      1970
  53 #endif /* !defined EPOCH_YEAR */
  54
  55 #ifndef TM_YEAR_BASE
  56 #define TM_YEAR_BASE    1900
  57 #endif /* !defined TM_YEAR_BASE */
  58
  59 #ifndef DAYSPERNYEAR
  60 #define DAYSPERNYEAR    365
  61 #endif /* !defined DAYSPERNYEAR */
  62
  63 #ifndef isleap
  64 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
  65 #endif /* !defined isleap */
  66
  67 #if HAVE_GETTEXT - 0
  68 #include "locale.h"     /* for setlocale */
  69 #include "libintl.h"
  70 #endif /* HAVE_GETTEXT - 0 */
  71
  72 #ifndef GNUC_or_lint
  73 #ifdef lint
  74 #define GNUC_or_lint
  75 #endif /* defined lint */
  76 #ifndef lint
  77 #ifdef __GNUC__
  78 #define GNUC_or_lint
  79 #endif /* defined __GNUC__ */
  80 #endif /* !defined lint */
  81 #endif /* !defined GNUC_or_lint */
  82
  83 #ifndef INITIALIZE
  84 #ifdef GNUC_or_lint
  85 #define INITIALIZE(x)   ((x) = 0)
  86 #endif /* defined GNUC_or_lint */
  87 #ifndef GNUC_or_lint
  88 #define INITIALIZE(x)
  89 #endif /* !defined GNUC_or_lint */
  90 #endif /* !defined INITIALIZE */
  91
  92 /*
  93 ** For the benefit of GNU folk...
  94 ** `_(MSGID)' uses the current locale's message library string for MSGID.
  95 ** The default is to use gettext if available, and use MSGID otherwise.
  96 */
  97
  98 #ifndef _
  99 #if HAVE_GETTEXT - 0
 100 #define _(msgid) gettext(msgid)
 101 #else /* !(HAVE_GETTEXT - 0) */
 102 #define _(msgid) msgid
 103 #endif /* !(HAVE_GETTEXT - 0) */
 104 #endif /* !defined _ */
 105
 106 #ifndef TZ_DOMAIN
 107 #define TZ_DOMAIN "tz"
 108 #endif /* !defined TZ_DOMAIN */
 109
 110 #ifndef P
 111 #ifdef __STDC__
 112 #define P(x)    x
 113 #endif /* defined __STDC__ */
 114 #ifndef __STDC__
 115 #define P(x)    ()
 116 #endif /* !defined __STDC__ */
 117 #endif /* !defined P */
 118
 119 extern char **  environ;
 120 extern int      getopt P((int argc, char * const argv[],
 121                           const char * options));
 122 extern char *   optarg;
 123 extern int      optind;
 124 extern char *   tzname[2];
 125
 126 static char *   abbr P((struct tm * tmp));
 127 static long     delta P((struct tm * newp, struct tm * oldp));
 128 static time_t   hunt P((char * name, time_t lot, time_t hit));
 129 static size_t   longest;
 130 static char *   progname;
 131 static void     show P((char * zone, time_t t, int v));
 132
 133 int
 134 main(argc, argv)
 135 int     argc;
 136 char *  argv[];
 137 {
 138         register int            i;
 139         register int            c;
 140         register int            vflag;
 141         register char *         cutoff;
 142         register int            cutyear;
 143         register long           cuttime;
 144         char **                 fakeenv;
 145         time_t                  now;
 146         time_t                  t;
 147         time_t                  newt;
 148         time_t                  hibit;
 149         struct tm               tm;
 150         struct tm               newtm;
 151
 152         INITIALIZE(cuttime);
 153 #if HAVE_GETTEXT - 0
 154         (void) setlocale(LC_CTYPE, "");
 155         (void) setlocale(LC_MESSAGES, "");
 156 #ifdef TZ_DOMAINDIR
 157         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 158 #endif /* defined(TEXTDOMAINDIR) */
 159         (void) textdomain(TZ_DOMAIN);
 160 #endif /* HAVE_GETTEXT - 0 */
 161         progname = argv[0];
 162         for (i = 1; i < argc; ++i)
 163                 if (strcmp(argv[i], "--version") == 0) {
 164                         (void) printf("%s\n", elsieid);
 165                         (void) exit(EXIT_SUCCESS);
 166                 }
 167         vflag = 0;
 168         cutoff = NULL;
 169         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 170                 if (c == 'v')
 171                         vflag = 1;
 172                 else    cutoff = optarg;
 173         if ((c != EOF && c != -1) ||
 174                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 175                         (void) fprintf(stderr,
 176 _("%s: usage is %s [ --version ] [ -v ] [ -c cutoff ] zonename ...\n"),
 177                                 argv[0], argv[0]);
 178                         (void) exit(EXIT_FAILURE);
 179         }
 180         if (cutoff != NULL) {
 181                 int     y;
 182
 183                 cutyear = atoi(cutoff);
 184                 cuttime = 0;
 185                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 186                         cuttime += DAYSPERNYEAR + isleap(y);
 187                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 188         }
 189         (void) time(&now);
 190         longest = 0;
 191         for (i = optind; i < argc; ++i)
 192                 if (strlen(argv[i]) > longest)
 193                         longest = strlen(argv[i]);
 194         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 195                 continue;
 196         {
 197                 register int    from;
 198                 register int    to;
 199
 200                 for (i = 0;  environ[i] != NULL;  ++i)
 201                         continue;
 202                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 203                         sizeof *fakeenv));
 204                 if (fakeenv == NULL ||
 205                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 206                                         (void) perror(progname);
 207                                         (void) exit(EXIT_FAILURE);
 208                 }
 209                 to = 0;
 210                 (void) strcpy(fakeenv[to++], "TZ=");
 211                 for (from = 0; environ[from] != NULL; ++from)
 212                         if (strncmp(environ[from], "TZ=", 3) != 0)
 213                                 fakeenv[to++] = environ[from];
 214                 fakeenv[to] = NULL;
 215                 environ = fakeenv;
 216         }
 217         for (i = optind; i < argc; ++i) {
 218                 static char     buf[MAX_STRING_LENGTH];
 219
 220                 (void) strcpy(&fakeenv[0][3], argv[i]);
 221                 if (!vflag) {
 222                         show(argv[i], now, FALSE);
 223                         continue;
 224                 }
 225                 /*
 226                 ** Get lowest value of t.
 227                 */
 228                 t = hibit;
 229                 if (t > 0)              /* time_t is unsigned */
 230                         t = 0;
 231                 show(argv[i], t, TRUE);
 232                 t += SECSPERHOUR * HOURSPERDAY;
 233                 show(argv[i], t, TRUE);
 234                 tm = *localtime(&t);
 235                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 236                 for ( ; ; ) {
 237                         if (cutoff != NULL && t >= cuttime)
 238                                 break;
 239                         newt = t + SECSPERHOUR * 12;
 240                         if (cutoff != NULL && newt >= cuttime)
 241                                 break;
 242                         if (newt <= t)
 243                                 break;
 244                         newtm = *localtime(&newt);
 245                         if (delta(&newtm, &tm) != (newt - t) ||
 246                                 newtm.tm_isdst != tm.tm_isdst ||
 247                                 strcmp(abbr(&newtm), buf) != 0) {
 248                                         newt = hunt(argv[i], t, newt);
 249                                         newtm = *localtime(&newt);
 250                                         (void) strncpy(buf, abbr(&newtm),
 251                                                 (sizeof buf) - 1);
 252                         }
 253                         t = newt;
 254                         tm = newtm;
 255                 }
 256                 /*
 257                 ** Get highest value of t.
 258                 */
 259                 t = ~((time_t) 0);
 260                 if (t < 0)              /* time_t is signed */
 261                         t &= ~hibit;
 262                 t -= SECSPERHOUR * HOURSPERDAY;
 263                 show(argv[i], t, TRUE);
 264                 t += SECSPERHOUR * HOURSPERDAY;
 265                 show(argv[i], t, TRUE);
 266         }
 267         if (fflush(stdout) || ferror(stdout)) {
 268                 (void) fprintf(stderr, "%s: ", argv[0]);
 269                 (void) perror(_("Error writing standard output"));
 270                 (void) exit(EXIT_FAILURE);
 271         }
 272         exit(EXIT_SUCCESS);
 273
 274         /* gcc -Wall pacifier */
 275         for ( ; ; )
 276                 continue;
 277 }
 278
 279 static time_t
 280 hunt(name, lot, hit)
 281 char *  name;
 282 time_t  lot;
 283 time_t  hit;
 284 {
 285         time_t          t;
 286         struct tm       lotm;
 287         struct tm       tm;
 288         static char     loab[MAX_STRING_LENGTH];
 289
 290         lotm = *localtime(&lot);
 291         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 292         while ((hit - lot) >= 2) {
 293                 t = lot / 2 + hit / 2;
 294                 if (t <= lot)
 295                         ++t;
 296                 else if (t >= hit)
 297                         --t;
 298                 tm = *localtime(&t);
 299                 if (delta(&tm, &lotm) == (t - lot) &&
 300                         tm.tm_isdst == lotm.tm_isdst &&
 301                         strcmp(abbr(&tm), loab) == 0) {
 302                                 lot = t;
 303                                 lotm = tm;
 304                 } else  hit = t;
 305         }
 306         show(name, lot, TRUE);
 307         show(name, hit, TRUE);
 308         return hit;
 309 }
 310
 311 /*
 312 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 313 */
 314
 315 static long
 316 delta(newp, oldp)
 317 struct tm *     newp;
 318 struct tm *     oldp;
 319 {
 320         long    result;
 321         int     tmy;
 322
 323         if (newp->tm_year < oldp->tm_year)
 324                 return -delta(oldp, newp);
 325         result = 0;
 326         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 327                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
 328         result += newp->tm_yday - oldp->tm_yday;
 329         result *= HOURSPERDAY;
 330         result += newp->tm_hour - oldp->tm_hour;
 331         result *= MINSPERHOUR;
 332         result += newp->tm_min - oldp->tm_min;
 333         result *= SECSPERMIN;
 334         result += newp->tm_sec - oldp->tm_sec;
 335         return result;
 336 }
 337
 338 static void
 339 show(zone, t, v)
 340 char *  zone;
 341 time_t  t;
 342 int     v;
 343 {
 344         struct tm *     tmp;
 345
 346         (void) printf("%-*s  ", (int) longest, zone);
 347         if (v)
 348                 (void) printf("%.24s UTC = ", asctime(gmtime(&t)));
 349         tmp = localtime(&t);
 350         (void) printf("%.24s", asctime(tmp));
 351         if (*abbr(tmp) != '\0')
 352                 (void) printf(" %s", abbr(tmp));
 353         if (v) {
 354                 (void) printf(" isdst=%d", tmp->tm_isdst);
 355 #ifdef TM_GMTOFF
 356                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 357 #endif /* defined TM_GMTOFF */
 358         }
 359         (void) printf("\n");
 360 }
 361
 362 static char *
 363 abbr(tmp)
 364 struct tm *     tmp;
 365 {
 366         register char * result;
 367         static char     nada;
 368
 369         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 370                 return &nada;
 371         result = tzname[tmp->tm_isdst];
 372         return (result == NULL) ? &nada : result;
 373 }