time/zdump.c

   1 #ifndef lint
   2 #ifndef NOID
   3 static char     elsieid[] = "@(#)zdump.c        7.12";
   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 */
  14 #include "string.h"     /* for strcpy */
  15 #include "sys/types.h"  /* for time_t */
  16 #include "time.h"       /* for struct tm */
  17
  18 #ifndef MAX_STRING_LENGTH
  19 #define MAX_STRING_LENGTH       1024
  20 #endif /* !defined MAX_STRING_LENGTH */
  21
  22 #ifndef TRUE
  23 #define TRUE            1
  24 #endif /* !defined TRUE */
  25
  26 #ifndef FALSE
  27 #define FALSE           0
  28 #endif /* !defined FALSE */
  29
  30 #ifndef EXIT_SUCCESS
  31 #define EXIT_SUCCESS    0
  32 #endif /* !defined EXIT_SUCCESS */
  33
  34 #ifndef EXIT_FAILURE
  35 #define EXIT_FAILURE    1
  36 #endif /* !defined EXIT_FAILURE */
  37
  38 #ifndef SECSPERMIN
  39 #define SECSPERMIN      60
  40 #endif /* !defined SECSPERMIN */
  41
  42 #ifndef MINSPERHOUR
  43 #define MINSPERHOUR     60
  44 #endif /* !defined MINSPERHOUR */
  45
  46 #ifndef SECSPERHOUR
  47 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
  48 #endif /* !defined SECSPERHOUR */
  49
  50 #ifndef HOURSPERDAY
  51 #define HOURSPERDAY     24
  52 #endif /* !defined HOURSPERDAY */
  53
  54 #ifndef EPOCH_YEAR
  55 #define EPOCH_YEAR      1970
  56 #endif /* !defined EPOCH_YEAR */
  57
  58 #ifndef TM_YEAR_BASE
  59 #define TM_YEAR_BASE    1900
  60 #endif /* !defined TM_YEAR_BASE */
  61
  62 #ifndef DAYSPERNYEAR
  63 #define DAYSPERNYEAR    365
  64 #endif /* !defined DAYSPERNYEAR */
  65
  66 #ifndef isleap
  67 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
  68 #endif /* !defined isleap */
  69
  70 #ifndef GNUC_or_lint
  71 #ifdef lint
  72 #define GNUC_or_lint
  73 #endif /* defined lint */
  74 #ifdef __GNUC__
  75 #define GNUC_or_lint
  76 #endif /* defined __GNUC__ */
  77 #endif /* !defined GNUC_or_lint */
  78
  79 #ifndef INITIALIZE
  80 #ifdef GNUC_or_lint
  81 #define INITIALIZE(x)   ((x) = 0)
  82 #endif /* defined GNUC_or_lint */
  83 #ifndef GNUC_or_lint
  84 #define INITIALIZE(x)
  85 #endif /* !defined GNUC_or_lint */
  86 #endif /* !defined INITIALIZE */
  87
  88 extern char **  environ;
  89 extern int      getopt();
  90 extern char *   optarg;
  91 extern int      optind;
  92 extern time_t   time();
  93 extern char *   tzname[2];
  94
  95 #ifdef USG
  96 extern void     exit();
  97 extern void     perror();
  98 #endif /* defined USG */
  99
 100 static char *   abbr();
 101 static long     delta();
 102 static time_t   hunt();
 103 static int      longest;
 104 static char *   progname;
 105 static void     show();
 106
 107 int
 108 main(argc, argv)
 109 int     argc;
 110 char *  argv[];
 111 {
 112         register int            i, c;
 113         register int            vflag;
 114         register char *         cutoff;
 115         register int            cutyear;
 116         register long           cuttime;
 117         char **                 fakeenv;
 118         time_t                  now;
 119         time_t                  t, newt;
 120         time_t                  hibit;
 121         struct tm               tm, newtm;
 122
 123         INITIALIZE(cuttime);
 124         progname = argv[0];
 125         vflag = 0;
 126         cutoff = NULL;
 127         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 128                 if (c == 'v')
 129                         vflag = 1;
 130                 else    cutoff = optarg;
 131         if (c != EOF ||
 132                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 133                         (void) fprintf(stderr,
 134 "%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n",
 135                                 argv[0], argv[0]);
 136                         (void) exit(EXIT_FAILURE);
 137         }
 138         if (cutoff != NULL) {
 139                 int     y;
 140
 141                 cutyear = atoi(cutoff);
 142                 cuttime = 0;
 143                 for (y = EPOCH_YEAR; y < cutyear; ++y)
 144                         cuttime += DAYSPERNYEAR + isleap(y);
 145                 cuttime *= SECSPERHOUR * HOURSPERDAY;
 146         }
 147         (void) time(&now);
 148         longest = 0;
 149         for (i = optind; i < argc; ++i)
 150                 if (strlen(argv[i]) > longest)
 151                         longest = strlen(argv[i]);
 152         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
 153                 continue;
 154         {
 155                 register int    from, to;
 156
 157                 for (i = 0;  environ[i] != NULL;  ++i)
 158                         continue;
 159                 fakeenv = (char **) malloc((i + 2) * sizeof *fakeenv);
 160                 if (fakeenv == NULL ||
 161                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 162                                 (void) perror(progname);
 163                                 (void) exit(EXIT_FAILURE);
 164                 }
 165                 to = 0;
 166                 (void) strcpy(fakeenv[to++], "TZ=");
 167                 for (from = 0; environ[from] != NULL; ++from)
 168                         if (strncmp(environ[from], "TZ=", 3) != 0)
 169                                 fakeenv[to++] = environ[from];
 170                 fakeenv[to] = NULL;
 171                 environ = fakeenv;
 172         }
 173         for (i = optind; i < argc; ++i) {
 174                 static char     buf[MAX_STRING_LENGTH];
 175
 176                 (void) strcpy(&fakeenv[0][3], argv[i]);
 177                 show(argv[i], now, FALSE);
 178                 if (!vflag)
 179                         continue;
 180                 /*
 181                 ** Get lowest value of t.
 182                 */
 183                 t = hibit;
 184                 if (t > 0)              /* time_t is unsigned */
 185                         t = 0;
 186                 show(argv[i], t, TRUE);
 187                 t += SECSPERHOUR * HOURSPERDAY;
 188                 show(argv[i], t, TRUE);
 189                 tm = *localtime(&t);
 190                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 191                 for ( ; ; ) {
 192                         if (cutoff != NULL && t >= cuttime)
 193                                 break;
 194                         newt = t + SECSPERHOUR * 12;
 195                         if (cutoff != NULL && newt >= cuttime)
 196                                 break;
 197                         if (newt <= t)
 198                                 break;
 199                         newtm = *localtime(&newt);
 200                         if (delta(&newtm, &tm) != (newt - t) ||
 201                                 newtm.tm_isdst != tm.tm_isdst ||
 202                                 strcmp(abbr(&newtm), buf) != 0) {
 203                                         newt = hunt(argv[i], t, newt);
 204                                         newtm = *localtime(&newt);
 205                                         (void) strncpy(buf, abbr(&newtm),
 206                                                 (sizeof buf) - 1);
 207                         }
 208                         t = newt;
 209                         tm = newtm;
 210                 }
 211                 /*
 212                 ** Get highest value of t.
 213                 */
 214                 t = ~((time_t) 0);
 215                 if (t < 0)              /* time_t is signed */
 216                         t &= ~hibit;
 217                 t -= SECSPERHOUR * HOURSPERDAY;
 218                 show(argv[i], t, TRUE);
 219                 t += SECSPERHOUR * HOURSPERDAY;
 220                 show(argv[i], t, TRUE);
 221         }
 222         if (fflush(stdout) || ferror(stdout)) {
 223                 (void) fprintf(stderr, "%s: Error writing standard output ",
 224                         argv[0]);
 225                 (void) perror("standard output");
 226                 (void) exit(EXIT_FAILURE);
 227         }
 228         exit(EXIT_SUCCESS);
 229
 230         /* gcc -Wall pacifier */
 231         for ( ; ; )
 232                 continue;
 233 }
 234
 235 static time_t
 236 hunt(name, lot, hit)
 237 char *  name;
 238 time_t  lot;
 239 time_t  hit;
 240 {
 241         time_t          t;
 242         struct tm       lotm;
 243         struct tm       tm;
 244         static char     loab[MAX_STRING_LENGTH];
 245
 246         lotm = *localtime(&lot);
 247         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 248         while ((hit - lot) >= 2) {
 249                 t = lot / 2 + hit / 2;
 250                 if (t <= lot)
 251                         ++t;
 252                 else if (t >= hit)
 253                         --t;
 254                 tm = *localtime(&t);
 255                 if (delta(&tm, &lotm) == (t - lot) &&
 256                         tm.tm_isdst == lotm.tm_isdst &&
 257                         strcmp(abbr(&tm), loab) == 0) {
 258                                 lot = t;
 259                                 lotm = tm;
 260                 } else  hit = t;
 261         }
 262         show(name, lot, TRUE);
 263         show(name, hit, TRUE);
 264         return hit;
 265 }
 266
 267 /*
 268 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
 269 */
 270
 271 static long
 272 delta(newp, oldp)
 273 struct tm *     newp;
 274 struct tm *     oldp;
 275 {
 276         long    result;
 277         int     tmy;
 278
 279         if (newp->tm_year < oldp->tm_year)
 280                 return -delta(oldp, newp);
 281         result = 0;
 282         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 283                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
 284         result += newp->tm_yday - oldp->tm_yday;
 285         result *= HOURSPERDAY;
 286         result += newp->tm_hour - oldp->tm_hour;
 287         result *= MINSPERHOUR;
 288         result += newp->tm_min - oldp->tm_min;
 289         result *= SECSPERMIN;
 290         result += newp->tm_sec - oldp->tm_sec;
 291         return result;
 292 }
 293
 294 extern struct tm *      localtime();
 295
 296 static void
 297 show(zone, t, v)
 298 char *  zone;
 299 time_t  t;
 300 int     v;
 301 {
 302         struct tm *     tmp;
 303
 304         (void) printf("%-*s  ", longest, zone);
 305         if (v)
 306                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
 307         tmp = localtime(&t);
 308         (void) printf("%.24s", asctime(tmp));
 309         if (*abbr(tmp) != '\0')
 310                 (void) printf(" %s", abbr(tmp));
 311         if (v) {
 312                 (void) printf(" isdst=%d", tmp->tm_isdst);
 313 #ifdef TM_GMTOFF
 314                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 315 #endif /* defined TM_GMTOFF */
 316         }
 317         (void) printf("\n");
 318 }
 319
 320 static char *
 321 abbr(tmp)
 322 struct tm *     tmp;
 323 {
 324         register char * result;
 325         static char     nada;
 326
 327         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 328                 return &nada;
 329         result = tzname[tmp->tm_isdst];
 330         return (result == NULL) ? &nada : result;
 331 }