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zdump.c revision 1.10.12.2 
      1 /*	$NetBSD: zdump.c,v 1.10.12.2 2002/03/22 20:42:46 nathanw Exp $	*/
      2 
      3 #include <sys/cdefs.h>
      4 #ifndef lint
      5 #ifndef NOID
      6 #if 0
      7 static char	elsieid[] = "@(#)zdump.c	7.29";
      8 #else
      9 __RCSID("$NetBSD: zdump.c,v 1.10.12.2 2002/03/22 20:42:46 nathanw Exp $");
     10 #endif
     11 #endif /* !defined NOID */
     12 #endif /* !defined lint */
     13 
     14 /*
     15 ** This code has been made independent of the rest of the time
     16 ** conversion package to increase confidence in the verification it provides.
     17 ** You can use this code to help in verifying other implementations.
     18 */
     19 
     20 #include "stdio.h"	/* for stdout, stderr, perror */
     21 #include "string.h"	/* for strcpy */
     22 #include "sys/types.h"	/* for time_t */
     23 #include "time.h"	/* for struct tm */
     24 #include "stdlib.h"	/* for exit, malloc, atoi */
     25 
     26 #ifndef MAX_STRING_LENGTH
     27 #define MAX_STRING_LENGTH	1024
     28 #endif /* !defined MAX_STRING_LENGTH */
     29 
     30 #ifndef TRUE
     31 #define TRUE		1
     32 #endif /* !defined TRUE */
     33 
     34 #ifndef FALSE
     35 #define FALSE		0
     36 #endif /* !defined FALSE */
     37 
     38 #ifndef EXIT_SUCCESS
     39 #define EXIT_SUCCESS	0
     40 #endif /* !defined EXIT_SUCCESS */
     41 
     42 #ifndef EXIT_FAILURE
     43 #define EXIT_FAILURE	1
     44 #endif /* !defined EXIT_FAILURE */
     45 
     46 #ifndef SECSPERMIN
     47 #define SECSPERMIN	60
     48 #endif /* !defined SECSPERMIN */
     49 
     50 #ifndef MINSPERHOUR
     51 #define MINSPERHOUR	60
     52 #endif /* !defined MINSPERHOUR */
     53 
     54 #ifndef SECSPERHOUR
     55 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
     56 #endif /* !defined SECSPERHOUR */
     57 
     58 #ifndef HOURSPERDAY
     59 #define HOURSPERDAY	24
     60 #endif /* !defined HOURSPERDAY */
     61 
     62 #ifndef EPOCH_YEAR
     63 #define EPOCH_YEAR	1970
     64 #endif /* !defined EPOCH_YEAR */
     65 
     66 #ifndef TM_YEAR_BASE
     67 #define TM_YEAR_BASE	1900
     68 #endif /* !defined TM_YEAR_BASE */
     69 
     70 #ifndef DAYSPERNYEAR
     71 #define DAYSPERNYEAR	365
     72 #endif /* !defined DAYSPERNYEAR */
     73 
     74 #ifndef isleap
     75 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
     76 #endif /* !defined isleap */
     77 
     78 #if HAVE_GETTEXT - 0
     79 #include "locale.h"	/* for setlocale */
     80 #include "libintl.h"
     81 #endif /* HAVE_GETTEXT - 0 */
     82 
     83 #ifndef GNUC_or_lint
     84 #ifdef lint
     85 #define GNUC_or_lint
     86 #endif /* defined lint */
     87 #ifndef lint
     88 #ifdef __GNUC__
     89 #define GNUC_or_lint
     90 #endif /* defined __GNUC__ */
     91 #endif /* !defined lint */
     92 #endif /* !defined GNUC_or_lint */
     93 
     94 #ifndef INITIALIZE
     95 #ifdef GNUC_or_lint
     96 #define INITIALIZE(x)	((x) = 0)
     97 #endif /* defined GNUC_or_lint */
     98 #ifndef GNUC_or_lint
     99 #define INITIALIZE(x)
    100 #endif /* !defined GNUC_or_lint */
    101 #endif /* !defined INITIALIZE */
    102 
    103 /*
    104 ** For the benefit of GNU folk...
    105 ** `_(MSGID)' uses the current locale's message library string for MSGID.
    106 ** The default is to use gettext if available, and use MSGID otherwise.
    107 */
    108 
    109 #ifndef _
    110 #if HAVE_GETTEXT - 0
    111 #define _(msgid) gettext(msgid)
    112 #else /* !(HAVE_GETTEXT - 0) */
    113 #define _(msgid) msgid
    114 #endif /* !(HAVE_GETTEXT - 0) */
    115 #endif /* !defined _ */
    116 
    117 #ifndef TZ_DOMAIN
    118 #define TZ_DOMAIN "tz"
    119 #endif /* !defined TZ_DOMAIN */
    120 
    121 #ifndef P
    122 #ifdef __STDC__
    123 #define P(x)	x
    124 #endif /* defined __STDC__ */
    125 #ifndef __STDC__
    126 #define P(x)	()
    127 #endif /* !defined __STDC__ */
    128 #endif /* !defined P */
    129 
    130 extern char **	environ;
    131 extern int	getopt P((int argc, char * const argv[],
    132 			  const char * options));
    133 extern char *	optarg;
    134 extern int	optind;
    135 
    136 static const char *	abbr P((struct tm * tmp));
    137 static long	delta P((struct tm * newp, struct tm * oldp));
    138 static time_t	hunt P((char * name, time_t lot, time_t	hit));
    139 int		main P((int, char **));
    140 static size_t	longest;
    141 static char *	progname;
    142 static void	show P((char * zone, time_t t, int v));
    143 
    144 int
    145 main(argc, argv)
    146 int	argc;
    147 char *	argv[];
    148 {
    149 	register int		i;
    150 	register int		c;
    151 	register int		vflag;
    152 	register char *		cutoff;
    153 	register int		cutyear;
    154 	register long		cuttime;
    155 	char **			fakeenv;
    156 	time_t			now;
    157 	time_t			t;
    158 	time_t			newt;
    159 	time_t			hibit;
    160 	struct tm		tm;
    161 	struct tm		newtm;
    162 
    163 	INITIALIZE(cuttime);
    164 #if HAVE_GETTEXT - 0
    165 	(void) setlocale(LC_MESSAGES, "");
    166 #ifdef TZ_DOMAINDIR
    167 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
    168 #endif /* defined(TEXTDOMAINDIR) */
    169 	(void) textdomain(TZ_DOMAIN);
    170 #endif /* HAVE_GETTEXT - 0 */
    171 	progname = argv[0];
    172 	vflag = 0;
    173 	cutoff = NULL;
    174 	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
    175 		if (c == 'v')
    176 			vflag = 1;
    177 		else	cutoff = optarg;
    178 	if ((c != EOF && c != -1) ||
    179 		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
    180 			(void) fprintf(stderr,
    181 _("%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n"),
    182 				argv[0], argv[0]);
    183 			(void) exit(EXIT_FAILURE);
    184 	}
    185 	if (cutoff != NULL) {
    186 		int	y;
    187 
    188 		cutyear = atoi(cutoff);
    189 		cuttime = 0;
    190 		for (y = EPOCH_YEAR; y < cutyear; ++y)
    191 			cuttime += DAYSPERNYEAR + isleap(y);
    192 		cuttime *= SECSPERHOUR * HOURSPERDAY;
    193 	}
    194 	(void) time(&now);
    195 	longest = 0;
    196 	for (i = optind; i < argc; ++i)
    197 		if (strlen(argv[i]) > longest)
    198 			longest = strlen(argv[i]);
    199 	for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
    200 		continue;
    201 	{
    202 		register int	from;
    203 		register int	to;
    204 
    205 		for (i = 0;  environ[i] != NULL;  ++i)
    206 			continue;
    207 		fakeenv = (char **) malloc((size_t) ((i + 2) *
    208 			sizeof *fakeenv));
    209 		if (fakeenv == NULL ||
    210 			(fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
    211 					(void) perror(progname);
    212 					(void) exit(EXIT_FAILURE);
    213 		}
    214 		to = 0;
    215 		(void)strcpy(fakeenv[to++], "TZ=");	/* XXX strcpy is safe */
    216 		for (from = 0; environ[from] != NULL; ++from)
    217 			if (strncmp(environ[from], "TZ=", 3) != 0)
    218 				fakeenv[to++] = environ[from];
    219 		fakeenv[to] = NULL;
    220 		environ = fakeenv;
    221 	}
    222 	for (i = optind; i < argc; ++i) {
    223 		static char	buf[MAX_STRING_LENGTH];
    224 
    225 		(void) strcpy(&fakeenv[0][3], argv[i]);	/* XXX strcpy is safe */
    226 		if (!vflag) {
    227 			show(argv[i], now, FALSE);
    228 			continue;
    229 		}
    230 		/*
    231 		** Get lowest value of t.
    232 		*/
    233 		t = hibit;
    234 		if (t > 0)		/* time_t is unsigned */
    235 			t = 0;
    236 		show(argv[i], t, TRUE);
    237 		t += SECSPERHOUR * HOURSPERDAY;
    238 		show(argv[i], t, TRUE);
    239 		tm = *localtime(&t);
    240 		(void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
    241 		for ( ; ; ) {
    242 			if (cutoff != NULL && t >= cuttime)
    243 				break;
    244 			newt = t + SECSPERHOUR * 12;
    245 			if (cutoff != NULL && newt >= cuttime)
    246 				break;
    247 			if (newt <= t)
    248 				break;
    249 			newtm = *localtime(&newt);
    250 			if (delta(&newtm, &tm) != (newt - t) ||
    251 				newtm.tm_isdst != tm.tm_isdst ||
    252 				strcmp(abbr(&newtm), buf) != 0) {
    253 					newt = hunt(argv[i], t, newt);
    254 					newtm = *localtime(&newt);
    255 					(void) strncpy(buf, abbr(&newtm),
    256 						(sizeof buf) - 1);
    257 			}
    258 			t = newt;
    259 			tm = newtm;
    260 		}
    261 		/*
    262 		** Get highest value of t.
    263 		*/
    264 		t = ~((time_t) 0);
    265 		if (t < 0)		/* time_t is signed */
    266 			t &= ~hibit;
    267 		t -= SECSPERHOUR * HOURSPERDAY;
    268 		show(argv[i], t, TRUE);
    269 		t += SECSPERHOUR * HOURSPERDAY;
    270 		show(argv[i], t, TRUE);
    271 	}
    272 	if (fflush(stdout) || ferror(stdout)) {
    273 		(void) fprintf(stderr, "%s: ", argv[0]);
    274 		(void) perror(_("Error writing standard output"));
    275 		(void) exit(EXIT_FAILURE);
    276 	}
    277 	exit(EXIT_SUCCESS);
    278 
    279 	/* gcc -Wall pacifier */
    280 	for ( ; ; )
    281 		continue;
    282 }
    283 
    284 static time_t
    285 hunt(name, lot, hit)
    286 char *	name;
    287 time_t	lot;
    288 time_t	hit;
    289 {
    290 	time_t		t;
    291 	struct tm	lotm;
    292 	struct tm	tm;
    293 	static char	loab[MAX_STRING_LENGTH];
    294 
    295 	lotm = *localtime(&lot);
    296 	(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
    297 	while ((hit - lot) >= 2) {
    298 		t = lot / 2 + hit / 2;
    299 		if (t <= lot)
    300 			++t;
    301 		else if (t >= hit)
    302 			--t;
    303 		tm = *localtime(&t);
    304 		if (delta(&tm, &lotm) == (t - lot) &&
    305 			tm.tm_isdst == lotm.tm_isdst &&
    306 			strcmp(abbr(&tm), loab) == 0) {
    307 				lot = t;
    308 				lotm = tm;
    309 		} else	hit = t;
    310 	}
    311 	show(name, lot, TRUE);
    312 	show(name, hit, TRUE);
    313 	return hit;
    314 }
    315 
    316 /*
    317 ** Thanks to Paul Eggert (eggert (at) twinsun.com) for logic used in delta.
    318 */
    319 
    320 static long
    321 delta(newp, oldp)
    322 struct tm *	newp;
    323 struct tm *	oldp;
    324 {
    325 	long	result;
    326 	int	tmy;
    327 
    328 	if (newp->tm_year < oldp->tm_year)
    329 		return -delta(oldp, newp);
    330 	result = 0;
    331 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
    332 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
    333 	result += newp->tm_yday - oldp->tm_yday;
    334 	result *= HOURSPERDAY;
    335 	result += newp->tm_hour - oldp->tm_hour;
    336 	result *= MINSPERHOUR;
    337 	result += newp->tm_min - oldp->tm_min;
    338 	result *= SECSPERMIN;
    339 	result += newp->tm_sec - oldp->tm_sec;
    340 	return result;
    341 }
    342 
    343 static void
    344 show(zone, t, v)
    345 char *	zone;
    346 time_t	t;
    347 int	v;
    348 {
    349 	struct tm *	tmp;
    350 
    351 	(void) printf("%-*s  ", (int) longest, zone);
    352 	if (v)
    353 		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
    354 	tmp = localtime(&t);
    355 	(void) printf("%.24s", asctime(tmp));
    356 	if (*abbr(tmp) != '\0')
    357 		(void) printf(" %s", abbr(tmp));
    358 	if (v) {
    359 		(void) printf(" isdst=%d", tmp->tm_isdst);
    360 #ifdef TM_GMTOFF
    361 		(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
    362 #endif /* defined TM_GMTOFF */
    363 	}
    364 	(void) printf("\n");
    365 }
    366 
    367 static const char *
    368 abbr(tmp)
    369 struct tm *	tmp;
    370 {
    371 	register const char *	result;
    372 	static const char	nada;
    373 
    374 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
    375 		return &nada;
    376 	result = tzname[tmp->tm_isdst];
    377 	return (result == NULL) ? &nada : result;
    378 }
    379