xref: /netbsd-src/lib/libc/time/zdump.c (revision 1ca5c1b28139779176bd5c13ad7c5f25c0bcd5f8)
1 /*	$NetBSD: zdump.c,v 1.10 1999/02/08 18:00:19 kleink Exp $	*/
2 
3 #include <sys/cdefs.h>
4 #ifndef lint
5 #ifndef NOID
6 #if 0
7 static char	elsieid[] = "@(#)zdump.c	7.28";
8 #else
9 __RCSID("$NetBSD: zdump.c,v 1.10 1999/02/08 18:00:19 kleink 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: Error writing "),
274 			argv[0]);
275 		(void) perror(_("standard output"));
276 		(void) exit(EXIT_FAILURE);
277 	}
278 	exit(EXIT_SUCCESS);
279 
280 	/* gcc -Wall pacifier */
281 	for ( ; ; )
282 		continue;
283 }
284 
285 static time_t
286 hunt(name, lot, hit)
287 char *	name;
288 time_t	lot;
289 time_t	hit;
290 {
291 	time_t		t;
292 	struct tm	lotm;
293 	struct tm	tm;
294 	static char	loab[MAX_STRING_LENGTH];
295 
296 	lotm = *localtime(&lot);
297 	(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
298 	while ((hit - lot) >= 2) {
299 		t = lot / 2 + hit / 2;
300 		if (t <= lot)
301 			++t;
302 		else if (t >= hit)
303 			--t;
304 		tm = *localtime(&t);
305 		if (delta(&tm, &lotm) == (t - lot) &&
306 			tm.tm_isdst == lotm.tm_isdst &&
307 			strcmp(abbr(&tm), loab) == 0) {
308 				lot = t;
309 				lotm = tm;
310 		} else	hit = t;
311 	}
312 	show(name, lot, TRUE);
313 	show(name, hit, TRUE);
314 	return hit;
315 }
316 
317 /*
318 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
319 */
320 
321 static long
322 delta(newp, oldp)
323 struct tm *	newp;
324 struct tm *	oldp;
325 {
326 	long	result;
327 	int	tmy;
328 
329 	if (newp->tm_year < oldp->tm_year)
330 		return -delta(oldp, newp);
331 	result = 0;
332 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
333 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
334 	result += newp->tm_yday - oldp->tm_yday;
335 	result *= HOURSPERDAY;
336 	result += newp->tm_hour - oldp->tm_hour;
337 	result *= MINSPERHOUR;
338 	result += newp->tm_min - oldp->tm_min;
339 	result *= SECSPERMIN;
340 	result += newp->tm_sec - oldp->tm_sec;
341 	return result;
342 }
343 
344 static void
345 show(zone, t, v)
346 char *	zone;
347 time_t	t;
348 int	v;
349 {
350 	struct tm *	tmp;
351 
352 	(void) printf("%-*s  ", (int) longest, zone);
353 	if (v)
354 		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
355 	tmp = localtime(&t);
356 	(void) printf("%.24s", asctime(tmp));
357 	if (*abbr(tmp) != '\0')
358 		(void) printf(" %s", abbr(tmp));
359 	if (v) {
360 		(void) printf(" isdst=%d", tmp->tm_isdst);
361 #ifdef TM_GMTOFF
362 		(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
363 #endif /* defined TM_GMTOFF */
364 	}
365 	(void) printf("\n");
366 }
367 
368 static const char *
369 abbr(tmp)
370 struct tm *	tmp;
371 {
372 	register const char *	result;
373 	static const char	nada;
374 
375 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
376 		return &nada;
377 	result = tzname[tmp->tm_isdst];
378 	return (result == NULL) ? &nada : result;
379 }
380