time/zdump.c

   1 #ifndef lint
   2 #ifndef NOID
   3 static char     elsieid[] = "@(#)zdump.c        7.25";
   4 #endif /* !defined NOID */
   5 #endif /* !defined lint */
   6
   7 /*
   8 ** This code has been made independent of the rest of the time
   9 ** conversion package to increase confidence in the verification it provides.
  10 ** You can use this code to help in verifying other implementations.
  11 */
  12
  13 #include "stdio.h"      /* for stdout, stderr, perror */
  14 #include "string.h"     /* for strcpy */
  15 #include "sys/types.h"  /* for time_t */
  16 #include "time.h"       /* for struct tm */
  17 #include "stdlib.h"     /* for exit, malloc, atoi */
  18
  19 #ifndef MAX_STRING_LENGTH
  20 #define MAX_STRING_LENGTH       1024
  21 #endif /* !defined MAX_STRING_LENGTH */
  22
  23 #ifndef TRUE
  24 #define TRUE            1
  25 #endif /* !defined TRUE */
  26
  27 #ifndef FALSE
  28 #define FALSE           0
  29 #endif /* !defined FALSE */
  30
  31 #ifndef EXIT_SUCCESS
  32 #define EXIT_SUCCESS    0
  33 #endif /* !defined EXIT_SUCCESS */
  34
  35 #ifndef EXIT_FAILURE
  36 #define EXIT_FAILURE    1
  37 #endif /* !defined EXIT_FAILURE */
  38
  39 #ifndef SECSPERMIN
  40 #define SECSPERMIN      60
  41 #endif /* !defined SECSPERMIN */
  42
  43 #ifndef MINSPERHOUR
  44 #define MINSPERHOUR     60
  45 #endif /* !defined MINSPERHOUR */
  46
  47 #ifndef SECSPERHOUR
  48 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
  49 #endif /* !defined SECSPERHOUR */
  50
  51 #ifndef HOURSPERDAY
  52 #define HOURSPERDAY     24
  53 #endif /* !defined HOURSPERDAY */
  54
  55 #ifndef EPOCH_YEAR
  56 #define EPOCH_YEAR      1970
  57 #endif /* !defined EPOCH_YEAR */
  58
  59 #ifndef TM_YEAR_BASE
  60 #define TM_YEAR_BASE    1900
  61 #endif /* !defined TM_YEAR_BASE */
  62
  63 #ifndef DAYSPERNYEAR
  64 #define DAYSPERNYEAR    365
  65 #endif /* !defined DAYSPERNYEAR */
  66
  67 #ifndef isleap
  68 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
  69 #endif /* !defined isleap */
  70
  71 #if HAVE_GETTEXT - 0
  72 #include "locale.h"     /* for setlocale */
  73 #include "libintl.h"
  74 #endif /* HAVE_GETTEXT - 0 */
  75
  76 #ifndef GNUC_or_lint
  77 #ifdef lint
  78 #define GNUC_or_lint
  79 #endif /* defined lint */
  80 #ifndef lint
  81 #ifdef __GNUC__
  82 #define GNUC_or_lint
  83 #endif /* defined __GNUC__ */
  84 #endif /* !defined lint */
  85 #endif /* !defined GNUC_or_lint */
  86
  87 #ifndef INITIALIZE
  88 #ifdef GNUC_or_lint
  89 #define INITIALIZE(x)   ((x) = 0)
  90 #endif /* defined GNUC_or_lint */
  91 #ifndef GNUC_or_lint
  92 #define INITIALIZE(x)
  93 #endif /* !defined GNUC_or_lint */
  94 #endif /* !defined INITIALIZE */
  95
  96 /*
  97 ** For the benefit of GNU folk...
  98 ** `_(MSGID)' uses the current locale's message library string for MSGID.
  99 ** The default is to use gettext if available, and use MSGID otherwise.
 100 */
 101
 102 #ifndef _
 103 #if HAVE_GETTEXT - 0
 104 #define _(msgid) gettext(msgid)
 105 #else /* !(HAVE_GETTEXT - 0) */
 106 #define _(msgid) msgid
 107 #endif /* !(HAVE_GETTEXT - 0) */
 108 #endif /* !defined _ */
 109
 110 #ifndef TZ_DOMAIN
 111 #define TZ_DOMAIN "tz"
 112 #endif /* !defined TZ_DOMAIN */
 113
 114 extern char **  environ;
 115 extern int      getopt();
 116 extern char *   optarg;
 117 extern int      optind;
 118 extern time_t   time();
 119 extern char *   tzname[2];
 120
 121 static char *   abbr();
 122 static long     delta();
 123 static time_t   hunt();
 124 static int      longest;
 125 static char *   progname;
 126 static void     show();
 127
 128 int
 129 main(argc, argv)
 130 int     argc;
 131 char *  argv[];
 132 {
 133         register int            i;
 134         register int            c;
 135         register int            vflag;
 136         register char *         cutoff;
 137         register int            cutyear;
 138         register long           cuttime;
 139         char **                 fakeenv;
 140         time_t                  now;
 141         time_t                  t;
 142         time_t                  newt;
 143         time_t                  hibit;
 144         struct tm               tm;
 145         struct tm               newtm;
 146
 147         INITIALIZE(cuttime);
 148 #if HAVE_GETTEXT - 0
 149         (void) setlocale(LC_MESSAGES, "");
 150 #ifdef TZ_DOMAINDIR
 151         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 152 #endif /* defined(TEXTDOMAINDIR) */
 153         (void) textdomain(TZ_DOMAIN);
 154 #endif /* HAVE_GETTEXT - 0 */
 155         progname = argv[0];
 156         vflag = 0;
 157         cutoff = NULL;
 158         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 159                 if (c == 'v')
 160                         vflag = 1;
 161                 else    cutoff = optarg;
 162         if ((c != EOF && c != -1) ||
 163                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 164                         (void) fprintf(stderr,
 165 _("%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n"),
 166                                 argv[0], argv[0]);
 167                         (void) exit(EXIT_FAILURE);
 168         }
 169         if (cutoff != NULL) {
 170                 int     y;
 171
 172                 cutyear = atoi(cutoff);
 173                 cuttime = 0;
 174                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 175                         cuttime += DAYSPERNYEAR + isleap(y);
 176                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 177         }
 178         (void) time(&now);
 179         longest = 0;
 180         for (i = optind; i < argc; ++i)
 181                 if (strlen(argv[i]) > longest)
 182                         longest = strlen(argv[i]);
 183         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 184                 continue;
 185         {
 186                 register int    from;
 187                 register int    to;
 188
 189                 for (i = 0;  environ[i] != NULL;  ++i)
 190                         continue;
 191                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 192                         sizeof *fakeenv));
 193                 if (fakeenv == NULL ||
 194                         (fakeenv[0] = (char *) malloc((size_t) (longest +
 195                                 4))) == NULL) {
 196                                         (void) perror(progname);
 197                                         (void) exit(EXIT_FAILURE);
 198                 }
 199                 to = 0;
 200                 (void) strcpy(fakeenv[to++], "TZ=");
 201                 for (from = 0; environ[from] != NULL; ++from)
 202                         if (strncmp(environ[from], "TZ=", 3) != 0)
 203                                 fakeenv[to++] = environ[from];
 204                 fakeenv[to] = NULL;
 205                 environ = fakeenv;
 206         }
 207         for (i = optind; i < argc; ++i) {
 208                 static char     buf[MAX_STRING_LENGTH];
 209
 210                 (void) strcpy(&fakeenv[0][3], argv[i]);
 211                 if (!vflag) {
 212                         show(argv[i], now, FALSE);
 213                         continue;
 214                 }
 215                 /*
 216                 ** Get lowest value of t.
 217                 */
 218                 t = hibit;
 219                 if (t > 0)              /* time_t is unsigned */
 220                         t = 0;
 221                 show(argv[i], t, TRUE);
 222                 t += SECSPERHOUR * HOURSPERDAY;
 223                 show(argv[i], t, TRUE);
 224                 tm = *localtime(&t);
 225                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 226                 for ( ; ; ) {
 227                         if (cutoff != NULL && t >= cuttime)
 228                                 break;
 229                         newt = t + SECSPERHOUR * 12;
 230                         if (cutoff != NULL && newt >= cuttime)
 231                                 break;
 232                         if (newt <= t)
 233                                 break;
 234                         newtm = *localtime(&newt);
 235                         if (delta(&newtm, &tm) != (newt - t) ||
 236                                 newtm.tm_isdst != tm.tm_isdst ||
 237                                 strcmp(abbr(&newtm), buf) != 0) {
 238                                         newt = hunt(argv[i], t, newt);
 239                                         newtm = *localtime(&newt);
 240                                         (void) strncpy(buf, abbr(&newtm),
 241                                                 (sizeof buf) - 1);
 242                         }
 243                         t = newt;
 244                         tm = newtm;
 245                 }
 246                 /*
 247                 ** Get highest value of t.
 248                 */
 249                 t = ~((time_t) 0);
 250                 if (t < 0)              /* time_t is signed */
 251                         t &= ~hibit;
 252                 t -= SECSPERHOUR * HOURSPERDAY;
 253                 show(argv[i], t, TRUE);
 254                 t += SECSPERHOUR * HOURSPERDAY;
 255                 show(argv[i], t, TRUE);
 256         }
 257         if (fflush(stdout) || ferror(stdout)) {
 258                 (void) fprintf(stderr, _("%s: Error writing standard output "),
 259                         argv[0]);
 260                 (void) perror(_("standard output"));
 261                 (void) exit(EXIT_FAILURE);
 262         }
 263         exit(EXIT_SUCCESS);
 264
 265         /* gcc -Wall pacifier */
 266         for ( ; ; )
 267                 continue;
 268 }
 269
 270 static time_t
 271 hunt(name, lot, hit)
 272 char *  name;
 273 time_t  lot;
 274 time_t  hit;
 275 {
 276         time_t          t;
 277         struct tm       lotm;
 278         struct tm       tm;
 279         static char     loab[MAX_STRING_LENGTH];
 280
 281         lotm = *localtime(&lot);
 282         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 283         while ((hit - lot) >= 2) {
 284                 t = lot / 2 + hit / 2;
 285                 if (t <= lot)
 286                         ++t;
 287                 else if (t >= hit)
 288                         --t;
 289                 tm = *localtime(&t);
 290                 if (delta(&tm, &lotm) == (t - lot) &&
 291                         tm.tm_isdst == lotm.tm_isdst &&
 292                         strcmp(abbr(&tm), loab) == 0) {
 293                                 lot = t;
 294                                 lotm = tm;
 295                 } else  hit = t;
 296         }
 297         show(name, lot, TRUE);
 298         show(name, hit, TRUE);
 299         return hit;
 300 }
 301
 302 /*
 303 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 304 */
 305
 306 static long
 307 delta(newp, oldp)
 308 struct tm *     newp;
 309 struct tm *     oldp;
 310 {
 311         long    result;
 312         int     tmy;
 313
 314         if (newp->tm_year < oldp->tm_year)
 315                 return -delta(oldp, newp);
 316         result = 0;
 317         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 318                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
 319         result += newp->tm_yday - oldp->tm_yday;
 320         result *= HOURSPERDAY;
 321         result += newp->tm_hour - oldp->tm_hour;
 322         result *= MINSPERHOUR;
 323         result += newp->tm_min - oldp->tm_min;
 324         result *= SECSPERMIN;
 325         result += newp->tm_sec - oldp->tm_sec;
 326         return result;
 327 }
 328
 329 extern struct tm *      localtime();
 330
 331 static void
 332 show(zone, t, v)
 333 char *  zone;
 334 time_t  t;
 335 int     v;
 336 {
 337         struct tm *     tmp;
 338
 339         (void) printf("%-*s  ", longest, zone);
 340         if (v)
 341                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
 342         tmp = localtime(&t);
 343         (void) printf("%.24s", asctime(tmp));
 344         if (*abbr(tmp) != '\0')
 345                 (void) printf(" %s", abbr(tmp));
 346         if (v) {
 347                 (void) printf(" isdst=%d", tmp->tm_isdst);
 348 #ifdef TM_GMTOFF
 349                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 350 #endif /* defined TM_GMTOFF */
 351         }
 352         (void) printf("\n");
 353 }
 354
 355 static char *
 356 abbr(tmp)
 357 struct tm *     tmp;
 358 {
 359         register char * result;
 360         static char     nada;
 361
 362         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 363                 return &nada;
 364         result = tzname[tmp->tm_isdst];
 365         return (result == NULL) ? &nada : result;
 366 }