timezone/zdump.c

   1 static char     elsieid[] = "@(#)zdump.c        7.40";
   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
  68 #include "locale.h"     /* for setlocale */
  69 #include "libintl.h"
  70 #endif /* HAVE_GETTEXT */
  71
  72 #ifndef GNUC_or_lint
  73 #ifdef lint
  74 #define GNUC_or_lint
  75 #else /* !defined lint */
  76 #ifdef __GNUC__
  77 #define GNUC_or_lint
  78 #endif /* defined __GNUC__ */
  79 #endif /* !defined lint */
  80 #endif /* !defined GNUC_or_lint */
  81
  82 #ifndef INITIALIZE
  83 #ifdef GNUC_or_lint
  84 #define INITIALIZE(x)   ((x) = 0)
  85 #else /* !defined GNUC_or_lint */
  86 #define INITIALIZE(x)
  87 #endif /* !defined GNUC_or_lint */
  88 #endif /* !defined INITIALIZE */
  89
  90 /*
  91 ** For the benefit of GNU folk...
  92 ** `_(MSGID)' uses the current locale's message library string for MSGID.
  93 ** The default is to use gettext if available, and use MSGID otherwise.
  94 */
  95
  96 #ifndef _
  97 #if HAVE_GETTEXT
  98 #define _(msgid) gettext(msgid)
  99 #else /* !HAVE_GETTEXT */
 100 #define _(msgid) msgid
 101 #endif /* !HAVE_GETTEXT */
 102 #endif /* !defined _ */
 103
 104 #ifndef TZ_DOMAIN
 105 #define TZ_DOMAIN "tz"
 106 #endif /* !defined TZ_DOMAIN */
 107
 108 #ifndef P
 109 #ifdef __STDC__
 110 #define P(x)    x
 111 #else /* !defined __STDC__ */
 112 #define P(x)    ()
 113 #endif /* !defined __STDC__ */
 114 #endif /* !defined P */
 115
 116 extern char **  environ;
 117 extern int      getopt P((int argc, char * const argv[],
 118                           const char * options));
 119 extern char *   optarg;
 120 extern int      optind;
 121 extern char *   tzname[2];
 122
 123 static char *   abbr P((struct tm * tmp));
 124 static long     delta P((struct tm * newp, struct tm * oldp));
 125 static time_t   hunt P((char * name, time_t lot, time_t hit));
 126 static size_t   longest;
 127 static char *   progname;
 128 static void     show P((char * zone, time_t t, int v));
 129 static void     dumptime P((const struct tm * tmp));
 130
 131 int
 132 main(argc, argv)
 133 int     argc;
 134 char *  argv[];
 135 {
 136         register int            i;
 137         register int            c;
 138         register int            vflag;
 139         register char *         cutoff;
 140         register int            cutyear;
 141         register long           cuttime;
 142         char **                 fakeenv;
 143         time_t                  now;
 144         time_t                  t;
 145         time_t                  newt;
 146         time_t                  hibit;
 147         struct tm               tm;
 148         struct tm               newtm;
 149
 150         INITIALIZE(cuttime);
 151 #if HAVE_GETTEXT
 152         (void) setlocale(LC_MESSAGES, "");
 153 #ifdef TZ_DOMAINDIR
 154         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 155 #endif /* defined TEXTDOMAINDIR */
 156         (void) textdomain(TZ_DOMAIN);
 157 #endif /* HAVE_GETTEXT */
 158         progname = argv[0];
 159         for (i = 1; i < argc; ++i)
 160                 if (strcmp(argv[i], "--version") == 0) {
 161                         (void) printf("%s\n", elsieid);
 162                         (void) exit(EXIT_SUCCESS);
 163                 }
 164         vflag = 0;
 165         cutoff = NULL;
 166         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 167                 if (c == 'v')
 168                         vflag = 1;
 169                 else    cutoff = optarg;
 170         if ((c != EOF && c != -1) ||
 171                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 172                         (void) fprintf(stderr,
 173 _("%s: usage is %s [ --version ] [ -v ] [ -c cutoff ] zonename ...\n"),
 174                                 argv[0], argv[0]);
 175                         (void) exit(EXIT_FAILURE);
 176         }
 177         if (cutoff != NULL) {
 178                 int     y;
 179
 180                 cutyear = atoi(cutoff);
 181                 cuttime = 0;
 182                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 183                         cuttime += DAYSPERNYEAR + isleap(y);
 184                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 185         }
 186         (void) time(&now);
 187         longest = 0;
 188         for (i = optind; i < argc; ++i)
 189                 if (strlen(argv[i]) > longest)
 190                         longest = strlen(argv[i]);
 191         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 192                 continue;
 193         {
 194                 register int    from;
 195                 register int    to;
 196
 197                 for (i = 0;  environ[i] != NULL;  ++i)
 198                         continue;
 199                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 200                         sizeof *fakeenv));
 201                 if (fakeenv == NULL ||
 202                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 203                                         (void) perror(progname);
 204                                         (void) exit(EXIT_FAILURE);
 205                 }
 206                 to = 0;
 207                 (void) strcpy(fakeenv[to++], "TZ=");
 208                 for (from = 0; environ[from] != NULL; ++from)
 209                         if (strncmp(environ[from], "TZ=", 3) != 0)
 210                                 fakeenv[to++] = environ[from];
 211                 fakeenv[to] = NULL;
 212                 environ = fakeenv;
 213         }
 214         for (i = optind; i < argc; ++i) {
 215                 static char     buf[MAX_STRING_LENGTH];
 216
 217                 (void) strcpy(&fakeenv[0][3], argv[i]);
 218                 if (!vflag) {
 219                         show(argv[i], now, FALSE);
 220                         continue;
 221                 }
 222                 /*
 223                 ** Get lowest value of t.
 224                 */
 225                 t = hibit;
 226                 if (t > 0)              /* time_t is unsigned */
 227                         t = 0;
 228                 show(argv[i], t, TRUE);
 229                 t += SECSPERHOUR * HOURSPERDAY;
 230                 show(argv[i], t, TRUE);
 231                 tm = *localtime(&t);
 232                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 233                 for ( ; ; ) {
 234                         if (cutoff != NULL && t >= cuttime)
 235                                 break;
 236                         newt = t + SECSPERHOUR * 12;
 237                         if (cutoff != NULL && newt >= cuttime)
 238                                 break;
 239                         if (newt <= t)
 240                                 break;
 241                         newtm = *localtime(&newt);
 242                         if (delta(&newtm, &tm) != (newt - t) ||
 243                                 newtm.tm_isdst != tm.tm_isdst ||
 244                                 strcmp(abbr(&newtm), buf) != 0) {
 245                                         newt = hunt(argv[i], t, newt);
 246                                         newtm = *localtime(&newt);
 247                                         (void) strncpy(buf, abbr(&newtm),
 248                                                 (sizeof buf) - 1);
 249                         }
 250                         t = newt;
 251                         tm = newtm;
 252                 }
 253                 /*
 254                 ** Get highest value of t.
 255                 */
 256                 t = ~((time_t) 0);
 257                 if (t < 0)              /* time_t is signed */
 258                         t &= ~hibit;
 259                 t -= SECSPERHOUR * HOURSPERDAY;
 260                 show(argv[i], t, TRUE);
 261                 t += SECSPERHOUR * HOURSPERDAY;
 262                 show(argv[i], t, TRUE);
 263         }
 264         if (fflush(stdout) || ferror(stdout)) {
 265                 (void) fprintf(stderr, "%s: ", argv[0]);
 266                 (void) perror(_("Error writing standard output"));
 267                 (void) exit(EXIT_FAILURE);
 268         }
 269         exit(EXIT_SUCCESS);
 270
 271         /* gcc -Wall pacifier */
 272         for ( ; ; )
 273                 continue;
 274 }
 275
 276 static time_t
 277 hunt(name, lot, hit)
 278 char *  name;
 279 time_t  lot;
 280 time_t  hit;
 281 {
 282         time_t          t;
 283         struct tm       lotm;
 284         struct tm       tm;
 285         static char     loab[MAX_STRING_LENGTH];
 286
 287         lotm = *localtime(&lot);
 288         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 289         while ((hit - lot) >= 2) {
 290                 t = lot / 2 + hit / 2;
 291                 if (t <= lot)
 292                         ++t;
 293                 else if (t >= hit)
 294                         --t;
 295                 tm = *localtime(&t);
 296                 if (delta(&tm, &lotm) == (t - lot) &&
 297                         tm.tm_isdst == lotm.tm_isdst &&
 298                         strcmp(abbr(&tm), loab) == 0) {
 299                                 lot = t;
 300                                 lotm = tm;
 301                 } else  hit = t;
 302         }
 303         show(name, lot, TRUE);
 304         show(name, hit, TRUE);
 305         return hit;
 306 }
 307
 308 /*
 309 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 310 */
 311
 312 static long
 313 delta(newp, oldp)
 314 struct tm *     newp;
 315 struct tm *     oldp;
 316 {
 317         long    result;
 318         int     tmy;
 319
 320         if (newp->tm_year < oldp->tm_year)
 321                 return -delta(oldp, newp);
 322         result = 0;
 323         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 324                 result += DAYSPERNYEAR + isleap(tmy + (long) TM_YEAR_BASE);
 325         result += newp->tm_yday - oldp->tm_yday;
 326         result *= HOURSPERDAY;
 327         result += newp->tm_hour - oldp->tm_hour;
 328         result *= MINSPERHOUR;
 329         result += newp->tm_min - oldp->tm_min;
 330         result *= SECSPERMIN;
 331         result += newp->tm_sec - oldp->tm_sec;
 332         return result;
 333 }
 334
 335 static void
 336 show(zone, t, v)
 337 char *  zone;
 338 time_t  t;
 339 int     v;
 340 {
 341         struct tm *     tmp;
 342
 343         (void) printf("%-*s  ", (int) longest, zone);
 344         if (v) {
 345                 dumptime(gmtime(&t));
 346                 (void) printf(" UTC = ");
 347         }
 348         tmp = localtime(&t);
 349         dumptime(tmp);
 350         if (*abbr(tmp) != '\0')
 351                 (void) printf(" %s", abbr(tmp));
 352         if (v) {
 353                 (void) printf(" isdst=%d", tmp->tm_isdst);
 354 #ifdef TM_GMTOFF
 355                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 356 #endif /* defined TM_GMTOFF */
 357         }
 358         (void) printf("\n");
 359 }
 360
 361 static char *
 362 abbr(tmp)
 363 struct tm *     tmp;
 364 {
 365         register char * result;
 366         static char     nada;
 367
 368         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 369                 return &nada;
 370         result = tzname[tmp->tm_isdst];
 371         return (result == NULL) ? &nada : result;
 372 }
 373
 374 static void
 375 dumptime(timeptr)
 376 register const struct tm *      timeptr;
 377 {
 378         static const char       wday_name[][3] = {
 379                 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 380         };
 381         static const char       mon_name[][3] = {
 382                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 383                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 384         };
 385         register const char *   wn;
 386         register const char *   mn;
 387
 388         /*
 389         ** The packaged versions of localtime and gmtime never put out-of-range
 390         ** values in tm_wday or tm_mon, but since this code might be compiled
 391         ** with other (perhaps experimental) versions, paranoia is in order.
 392         */
 393         if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
 394                 (int) (sizeof wday_name / sizeof wday_name[0]))
 395                         wn = "???";
 396         else            wn = wday_name[timeptr->tm_wday];
 397         if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
 398                 (int) (sizeof mon_name / sizeof mon_name[0]))
 399                         mn = "???";
 400         else            mn = mon_name[timeptr->tm_mon];
 401         (void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d %ld",
 402                 wn, mn,
 403                 timeptr->tm_mday, timeptr->tm_hour,
 404                 timeptr->tm_min, timeptr->tm_sec,
 405                 timeptr->tm_year + (long) TM_YEAR_BASE);
 406 }