time/zdump.c

   1 #ifndef lint
   2 #ifndef NOID
   3 static char     elsieid[] = "@(#)zdump.c        7.20";
   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 #ifndef GNUC_or_lint
  72 #ifdef lint
  73 #define GNUC_or_lint
  74 #endif /* defined lint */
  75 #ifndef 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 #endif /* defined GNUC_or_lint */
  86 #ifndef GNUC_or_lint
  87 #define INITIALIZE(x)
  88 #endif /* !defined GNUC_or_lint */
  89 #endif /* !defined INITIALIZE */
  90
  91 extern char **  environ;
  92 extern int      getopt();
  93 extern char *   optarg;
  94 extern int      optind;
  95 extern time_t   time();
  96 extern char *   tzname[2];
  97
  98 static char *   abbr();
  99 static long     delta();
 100 static time_t   hunt();
 101 static int      longest;
 102 static char *   progname;
 103 static void     show();
 104
 105 int
 106 main(argc, argv)
 107 int     argc;
 108 char *  argv[];
 109 {
 110         register int            i;
 111         register int            c;
 112         register int            vflag;
 113         register char *         cutoff;
 114         register int            cutyear;
 115         register long           cuttime;
 116         char **                 fakeenv;
 117         time_t                  now;
 118         time_t                  t;
 119         time_t                  newt;
 120         time_t                  hibit;
 121         struct tm               tm;
 122         struct tm               newtm;
 123
 124         INITIALIZE(cuttime);
 125         progname = argv[0];
 126         vflag = 0;
 127         cutoff = NULL;
 128         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 129                 if (c == 'v')
 130                         vflag = 1;
 131                 else    cutoff = optarg;
 132         if (c != EOF ||
 133                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 134                         (void) fprintf(stderr,
 135 "%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n",
 136                                 argv[0], argv[0]);
 137                         (void) exit(EXIT_FAILURE);
 138         }
 139         if (cutoff != NULL) {
 140                 int     y;
 141
 142                 cutyear = atoi(cutoff);
 143                 cuttime = 0;
 144                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 145                         cuttime += DAYSPERNYEAR + isleap(y);
 146                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 147         }
 148         (void) time(&now);
 149         longest = 0;
 150         for (i = optind; i < argc; ++i)
 151                 if (strlen(argv[i]) > longest)
 152                         longest = strlen(argv[i]);
 153         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 154                 continue;
 155         {
 156                 register int    from;
 157                 register int    to;
 158
 159                 for (i = 0;  environ[i] != NULL;  ++i)
 160                         continue;
 161                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 162                         sizeof *fakeenv));
 163                 if (fakeenv == NULL ||
 164                         (fakeenv[0] = (char *) malloc((size_t) (longest +
 165                                 4))) == NULL) {
 166                                         (void) perror(progname);
 167                                         (void) exit(EXIT_FAILURE);
 168                 }
 169                 to = 0;
 170                 (void) strcpy(fakeenv[to++], "TZ=");
 171                 for (from = 0; environ[from] != NULL; ++from)
 172                         if (strncmp(environ[from], "TZ=", 3) != 0)
 173                                 fakeenv[to++] = environ[from];
 174                 fakeenv[to] = NULL;
 175                 environ = fakeenv;
 176         }
 177         for (i = optind; i < argc; ++i) {
 178                 static char     buf[MAX_STRING_LENGTH];
 179
 180                 (void) strcpy(&fakeenv[0][3], argv[i]);
 181                 show(argv[i], now, FALSE);
 182                 if (!vflag)
 183                         continue;
 184                 /*
 185                 ** Get lowest value of t.
 186                 */
 187                 t = hibit;
 188                 if (t > 0)              /* time_t is unsigned */
 189                         t = 0;
 190                 show(argv[i], t, TRUE);
 191                 t += SECSPERHOUR * HOURSPERDAY;
 192                 show(argv[i], t, TRUE);
 193                 tm = *localtime(&t);
 194                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 195                 for ( ; ; ) {
 196                         if (cutoff != NULL && t >= cuttime)
 197                                 break;
 198                         newt = t + SECSPERHOUR * 12;
 199                         if (cutoff != NULL && newt >= cuttime)
 200                                 break;
 201                         if (newt <= t)
 202                                 break;
 203                         newtm = *localtime(&newt);
 204                         if (delta(&newtm, &tm) != (newt - t) ||
 205                                 newtm.tm_isdst != tm.tm_isdst ||
 206                                 strcmp(abbr(&newtm), buf) != 0) {
 207                                         newt = hunt(argv[i], t, newt);
 208                                         newtm = *localtime(&newt);
 209                                         (void) strncpy(buf, abbr(&newtm),
 210                                                 (sizeof buf) - 1);
 211                         }
 212                         t = newt;
 213                         tm = newtm;
 214                 }
 215                 /*
 216                 ** Get highest value of t.
 217                 */
 218                 t = ~((time_t) 0);
 219                 if (t < 0)              /* time_t is signed */
 220                         t &= ~hibit;
 221                 t -= SECSPERHOUR * HOURSPERDAY;
 222                 show(argv[i], t, TRUE);
 223                 t += SECSPERHOUR * HOURSPERDAY;
 224                 show(argv[i], t, TRUE);
 225         }
 226         if (fflush(stdout) || ferror(stdout)) {
 227                 (void) fprintf(stderr, "%s: Error writing standard output ",
 228                         argv[0]);
 229                 (void) perror("standard output");
 230                 (void) exit(EXIT_FAILURE);
 231         }
 232         exit(EXIT_SUCCESS);
 233
 234         /* gcc -Wall pacifier */
 235         for ( ; ; )
 236                 continue;
 237 }
 238
 239 static time_t
 240 hunt(name, lot, hit)
 241 char *  name;
 242 time_t  lot;
 243 time_t  hit;
 244 {
 245         time_t          t;
 246         struct tm       lotm;
 247         struct tm       tm;
 248         static char     loab[MAX_STRING_LENGTH];
 249
 250         lotm = *localtime(&lot);
 251         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 252         while ((hit - lot) >= 2) {
 253                 t = lot / 2 + hit / 2;
 254                 if (t <= lot)
 255                         ++t;
 256                 else if (t >= hit)
 257                         --t;
 258                 tm = *localtime(&t);
 259                 if (delta(&tm, &lotm) == (t - lot) &&
 260                         tm.tm_isdst == lotm.tm_isdst &&
 261                         strcmp(abbr(&tm), loab) == 0) {
 262                                 lot = t;
 263                                 lotm = tm;
 264                 } else  hit = t;
 265         }
 266         show(name, lot, TRUE);
 267         show(name, hit, TRUE);
 268         return hit;
 269 }
 270
 271 /*
 272 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 273 */
 274
 275 static long
 276 delta(newp, oldp)
 277 struct tm *     newp;
 278 struct tm *     oldp;
 279 {
 280         long    result;
 281         int     tmy;
 282
 283         if (newp->tm_year < oldp->tm_year)
 284                 return -delta(oldp, newp);
 285         result = 0;
 286         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 287                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
 288         result += newp->tm_yday - oldp->tm_yday;
 289         result *= HOURSPERDAY;
 290         result += newp->tm_hour - oldp->tm_hour;
 291         result *= MINSPERHOUR;
 292         result += newp->tm_min - oldp->tm_min;
 293         result *= SECSPERMIN;
 294         result += newp->tm_sec - oldp->tm_sec;
 295         return result;
 296 }
 297
 298 extern struct tm *      localtime();
 299
 300 static void
 301 show(zone, t, v)
 302 char *  zone;
 303 time_t  t;
 304 int     v;
 305 {
 306         struct tm *     tmp;
 307
 308         (void) printf("%-*s  ", longest, zone);
 309         if (v)
 310                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
 311         tmp = localtime(&t);
 312         (void) printf("%.24s", asctime(tmp));
 313         if (*abbr(tmp) != '\0')
 314                 (void) printf(" %s", abbr(tmp));
 315         if (v) {
 316                 (void) printf(" isdst=%d", tmp->tm_isdst);
 317 #ifdef TM_GMTOFF
 318                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 319 #endif /* defined TM_GMTOFF */
 320         }
 321         (void) printf("\n");
 322 }
 323
 324 static char *
 325 abbr(tmp)
 326 struct tm *     tmp;
 327 {
 328         register char * result;
 329         static char     nada;
 330
 331         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 332                 return &nada;
 333         result = tzname[tmp->tm_isdst];
 334         return (result == NULL) ? &nada : result;
 335 }