time/zdump.c

   1 #ifndef lint
   2 #ifndef NOID
   3 static char     elsieid[] = "@(#)zdump.c        7.26";
   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 #ifndef P
 115 #ifdef __STDC__
 116 #define P(x)    x
 117 #endif /* defined __STDC__ */
 118 #ifndef __STDC__
 119 #define P(x)    ()
 120 #endif /* !defined __STDC__ */
 121 #endif /* !defined P */
 122
 123 extern char **  environ;
 124 extern int      getopt P((int argc, char * const argv[],
 125                           const char * options));
 126 extern char *   optarg;
 127 extern int      optind;
 128 extern char *   tzname[2];
 129
 130 static char *   abbr P((struct tm * tmp));
 131 static long     delta P((struct tm * newp, struct tm * oldp));
 132 static time_t   hunt P((char * name, time_t lot, time_t hit));
 133 static size_t   longest;
 134 static char *   progname;
 135 static void     show P((char * zone, time_t t, int v));
 136
 137 int
 138 main(argc, argv)
 139 int     argc;
 140 char *  argv[];
 141 {
 142         register int            i;
 143         register int            c;
 144         register int            vflag;
 145         register char *         cutoff;
 146         register int            cutyear;
 147         register long           cuttime;
 148         char **                 fakeenv;
 149         time_t                  now;
 150         time_t                  t;
 151         time_t                  newt;
 152         time_t                  hibit;
 153         struct tm               tm;
 154         struct tm               newtm;
 155
 156         INITIALIZE(cuttime);
 157 #if HAVE_GETTEXT - 0
 158         (void) setlocale(LC_MESSAGES, "");
 159 #ifdef TZ_DOMAINDIR
 160         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 161 #endif /* defined(TEXTDOMAINDIR) */
 162         (void) textdomain(TZ_DOMAIN);
 163 #endif /* HAVE_GETTEXT - 0 */
 164         progname = argv[0];
 165         vflag = 0;
 166         cutoff = NULL;
 167         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 168                 if (c == 'v')
 169                         vflag = 1;
 170                 else    cutoff = optarg;
 171         if ((c != EOF && c != -1) ||
 172                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 173                         (void) fprintf(stderr,
 174 _("%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n"),
 175                                 argv[0], argv[0]);
 176                         (void) exit(EXIT_FAILURE);
 177         }
 178         if (cutoff != NULL) {
 179                 int     y;
 180
 181                 cutyear = atoi(cutoff);
 182                 cuttime = 0;
 183                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 184                         cuttime += DAYSPERNYEAR + isleap(y);
 185                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 186         }
 187         (void) time(&now);
 188         longest = 0;
 189         for (i = optind; i < argc; ++i)
 190                 if (strlen(argv[i]) > longest)
 191                         longest = strlen(argv[i]);
 192         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 193                 continue;
 194         {
 195                 register int    from;
 196                 register int    to;
 197
 198                 for (i = 0;  environ[i] != NULL;  ++i)
 199                         continue;
 200                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 201                         sizeof *fakeenv));
 202                 if (fakeenv == NULL ||
 203                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 204                                         (void) perror(progname);
 205                                         (void) exit(EXIT_FAILURE);
 206                 }
 207                 to = 0;
 208                 (void) strcpy(fakeenv[to++], "TZ=");
 209                 for (from = 0; environ[from] != NULL; ++from)
 210                         if (strncmp(environ[from], "TZ=", 3) != 0)
 211                                 fakeenv[to++] = environ[from];
 212                 fakeenv[to] = NULL;
 213                 environ = fakeenv;
 214         }
 215         for (i = optind; i < argc; ++i) {
 216                 static char     buf[MAX_STRING_LENGTH];
 217
 218                 (void) strcpy(&fakeenv[0][3], argv[i]);
 219                 if (!vflag) {
 220                         show(argv[i], now, FALSE);
 221                         continue;
 222                 }
 223                 /*
 224                 ** Get lowest value of t.
 225                 */
 226                 t = hibit;
 227                 if (t > 0)              /* time_t is unsigned */
 228                         t = 0;
 229                 show(argv[i], t, TRUE);
 230                 t += SECSPERHOUR * HOURSPERDAY;
 231                 show(argv[i], t, TRUE);
 232                 tm = *localtime(&t);
 233                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 234                 for ( ; ; ) {
 235                         if (cutoff != NULL && t >= cuttime)
 236                                 break;
 237                         newt = t + SECSPERHOUR * 12;
 238                         if (cutoff != NULL && newt >= cuttime)
 239                                 break;
 240                         if (newt <= t)
 241                                 break;
 242                         newtm = *localtime(&newt);
 243                         if (delta(&newtm, &tm) != (newt - t) ||
 244                                 newtm.tm_isdst != tm.tm_isdst ||
 245                                 strcmp(abbr(&newtm), buf) != 0) {
 246                                         newt = hunt(argv[i], t, newt);
 247                                         newtm = *localtime(&newt);
 248                                         (void) strncpy(buf, abbr(&newtm),
 249                                                 (sizeof buf) - 1);
 250                         }
 251                         t = newt;
 252                         tm = newtm;
 253                 }
 254                 /*
 255                 ** Get highest value of t.
 256                 */
 257                 t = ~((time_t) 0);
 258                 if (t < 0)              /* time_t is signed */
 259                         t &= ~hibit;
 260                 t -= SECSPERHOUR * HOURSPERDAY;
 261                 show(argv[i], t, TRUE);
 262                 t += SECSPERHOUR * HOURSPERDAY;
 263                 show(argv[i], t, TRUE);
 264         }
 265         if (fflush(stdout) || ferror(stdout)) {
 266                 (void) fprintf(stderr, _("%s: Error writing standard output "),
 267                         argv[0]);
 268                 (void) perror(_("standard output"));
 269                 (void) exit(EXIT_FAILURE);
 270         }
 271         exit(EXIT_SUCCESS);
 272
 273         /* gcc -Wall pacifier */
 274         for ( ; ; )
 275                 continue;
 276 }
 277
 278 static time_t
 279 hunt(name, lot, hit)
 280 char *  name;
 281 time_t  lot;
 282 time_t  hit;
 283 {
 284         time_t          t;
 285         struct tm       lotm;
 286         struct tm       tm;
 287         static char     loab[MAX_STRING_LENGTH];
 288
 289         lotm = *localtime(&lot);
 290         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 291         while ((hit - lot) >= 2) {
 292                 t = lot / 2 + hit / 2;
 293                 if (t <= lot)
 294                         ++t;
 295                 else if (t >= hit)
 296                         --t;
 297                 tm = *localtime(&t);
 298                 if (delta(&tm, &lotm) == (t - lot) &&
 299                         tm.tm_isdst == lotm.tm_isdst &&
 300                         strcmp(abbr(&tm), loab) == 0) {
 301                                 lot = t;
 302                                 lotm = tm;
 303                 } else  hit = t;
 304         }
 305         show(name, lot, TRUE);
 306         show(name, hit, TRUE);
 307         return hit;
 308 }
 309
 310 /*
 311 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 312 */
 313
 314 static long
 315 delta(newp, oldp)
 316 struct tm *     newp;
 317 struct tm *     oldp;
 318 {
 319         long    result;
 320         int     tmy;
 321
 322         if (newp->tm_year < oldp->tm_year)
 323                 return -delta(oldp, newp);
 324         result = 0;
 325         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 326                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
 327         result += newp->tm_yday - oldp->tm_yday;
 328         result *= HOURSPERDAY;
 329         result += newp->tm_hour - oldp->tm_hour;
 330         result *= MINSPERHOUR;
 331         result += newp->tm_min - oldp->tm_min;
 332         result *= SECSPERMIN;
 333         result += newp->tm_sec - oldp->tm_sec;
 334         return result;
 335 }
 336
 337 static void
 338 show(zone, t, v)
 339 char *  zone;
 340 time_t  t;
 341 int     v;
 342 {
 343         struct tm *     tmp;
 344
 345         (void) printf("%-*s  ", (int) longest, zone);
 346         if (v)
 347                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
 348         tmp = localtime(&t);
 349         (void) printf("%.24s", asctime(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 }