xref: /netbsd-src/lib/libc/time/zdump.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: zdump.c,v 1.14 2003/10/29 20:43:27 kleink Exp $	*/
2 
3 #include <sys/cdefs.h>
4 #ifndef lint
5 #ifndef NOID
6 __RCSID("$NetBSD: zdump.c,v 1.14 2003/10/29 20:43:27 kleink Exp $");
7 #endif /* !defined NOID */
8 #endif /* !defined lint */
9 
10 static char	elsieid[] = "@(#)zdump.c	7.31";
11 
12 /*
13 ** This code has been made independent of the rest of the time
14 ** conversion package to increase confidence in the verification it provides.
15 ** You can use this code to help in verifying other implementations.
16 */
17 
18 #include "stdio.h"	/* for stdout, stderr, perror */
19 #include "string.h"	/* for strcpy */
20 #include "sys/types.h"	/* for time_t */
21 #include "time.h"	/* for struct tm */
22 #include "stdlib.h"	/* for exit, malloc, atoi */
23 
24 #ifndef MAX_STRING_LENGTH
25 #define MAX_STRING_LENGTH	1024
26 #endif /* !defined MAX_STRING_LENGTH */
27 
28 #ifndef TRUE
29 #define TRUE		1
30 #endif /* !defined TRUE */
31 
32 #ifndef FALSE
33 #define FALSE		0
34 #endif /* !defined FALSE */
35 
36 #ifndef EXIT_SUCCESS
37 #define EXIT_SUCCESS	0
38 #endif /* !defined EXIT_SUCCESS */
39 
40 #ifndef EXIT_FAILURE
41 #define EXIT_FAILURE	1
42 #endif /* !defined EXIT_FAILURE */
43 
44 #ifndef SECSPERMIN
45 #define SECSPERMIN	60
46 #endif /* !defined SECSPERMIN */
47 
48 #ifndef MINSPERHOUR
49 #define MINSPERHOUR	60
50 #endif /* !defined MINSPERHOUR */
51 
52 #ifndef SECSPERHOUR
53 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
54 #endif /* !defined SECSPERHOUR */
55 
56 #ifndef HOURSPERDAY
57 #define HOURSPERDAY	24
58 #endif /* !defined HOURSPERDAY */
59 
60 #ifndef EPOCH_YEAR
61 #define EPOCH_YEAR	1970
62 #endif /* !defined EPOCH_YEAR */
63 
64 #ifndef TM_YEAR_BASE
65 #define TM_YEAR_BASE	1900
66 #endif /* !defined TM_YEAR_BASE */
67 
68 #ifndef DAYSPERNYEAR
69 #define DAYSPERNYEAR	365
70 #endif /* !defined DAYSPERNYEAR */
71 
72 #ifndef isleap
73 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
74 #endif /* !defined isleap */
75 
76 #if HAVE_GETTEXT - 0
77 #include "locale.h"	/* for setlocale */
78 #include "libintl.h"
79 #endif /* HAVE_GETTEXT - 0 */
80 
81 #ifndef GNUC_or_lint
82 #ifdef lint
83 #define GNUC_or_lint
84 #endif /* defined lint */
85 #ifndef lint
86 #ifdef __GNUC__
87 #define GNUC_or_lint
88 #endif /* defined __GNUC__ */
89 #endif /* !defined lint */
90 #endif /* !defined GNUC_or_lint */
91 
92 #ifndef INITIALIZE
93 #ifdef GNUC_or_lint
94 #define INITIALIZE(x)	((x) = 0)
95 #endif /* defined GNUC_or_lint */
96 #ifndef GNUC_or_lint
97 #define INITIALIZE(x)
98 #endif /* !defined GNUC_or_lint */
99 #endif /* !defined INITIALIZE */
100 
101 /*
102 ** For the benefit of GNU folk...
103 ** `_(MSGID)' uses the current locale's message library string for MSGID.
104 ** The default is to use gettext if available, and use MSGID otherwise.
105 */
106 
107 #ifndef _
108 #if HAVE_GETTEXT - 0
109 #define _(msgid) gettext(msgid)
110 #else /* !(HAVE_GETTEXT - 0) */
111 #define _(msgid) msgid
112 #endif /* !(HAVE_GETTEXT - 0) */
113 #endif /* !defined _ */
114 
115 #ifndef TZ_DOMAIN
116 #define TZ_DOMAIN "tz"
117 #endif /* !defined TZ_DOMAIN */
118 
119 #ifndef P
120 #define P(x)	x
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 
129 static const char *	abbr P((struct tm * tmp));
130 static long	delta P((struct tm * newp, struct tm * oldp));
131 static time_t	hunt P((char * name, time_t lot, time_t	hit));
132 int		main P((int, char **));
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 	for (i = 1; i < argc; ++i)
166 		if (strcmp(argv[i], "--version") == 0) {
167 			(void) printf("%s\n", elsieid);
168 			(void) exit(EXIT_SUCCESS);
169 		}
170 	vflag = 0;
171 	cutoff = NULL;
172 	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
173 		if (c == 'v')
174 			vflag = 1;
175 		else	cutoff = optarg;
176 	if ((c != EOF && c != -1) ||
177 		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
178 			(void) fprintf(stderr,
179 _("%s: usage is %s [ --version ] [ -v ] [ -c cutoff ] zonename ...\n"),
180 				argv[0], argv[0]);
181 			(void) exit(EXIT_FAILURE);
182 	}
183 	if (cutoff != NULL) {
184 		int	y;
185 
186 		cutyear = atoi(cutoff);
187 		cuttime = 0;
188 		for (y = EPOCH_YEAR; y < cutyear; ++y)
189 			cuttime += DAYSPERNYEAR + isleap(y);
190 		cuttime *= SECSPERHOUR * HOURSPERDAY;
191 	}
192 	(void) time(&now);
193 	longest = 0;
194 	for (i = optind; i < argc; ++i)
195 		if (strlen(argv[i]) > longest)
196 			longest = strlen(argv[i]);
197 	for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
198 		continue;
199 	{
200 		register int	from;
201 		register int	to;
202 
203 		for (i = 0;  environ[i] != NULL;  ++i)
204 			continue;
205 		fakeenv = (char **) malloc((size_t) ((i + 2) *
206 			sizeof *fakeenv));
207 		if (fakeenv == NULL ||
208 			(fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
209 					(void) perror(progname);
210 					(void) exit(EXIT_FAILURE);
211 		}
212 		to = 0;
213 		(void)strcpy(fakeenv[to++], "TZ=");	/* XXX strcpy is safe */
214 		for (from = 0; environ[from] != NULL; ++from)
215 			if (strncmp(environ[from], "TZ=", 3) != 0)
216 				fakeenv[to++] = environ[from];
217 		fakeenv[to] = NULL;
218 		environ = fakeenv;
219 	}
220 	for (i = optind; i < argc; ++i) {
221 		static char	buf[MAX_STRING_LENGTH];
222 
223 		(void) strcpy(&fakeenv[0][3], argv[i]);	/* XXX strcpy is safe */
224 		if (!vflag) {
225 			show(argv[i], now, FALSE);
226 			continue;
227 		}
228 		/*
229 		** Get lowest value of t.
230 		*/
231 		t = hibit;
232 		if (t > 0)		/* time_t is unsigned */
233 			t = 0;
234 		show(argv[i], t, TRUE);
235 		t += SECSPERHOUR * HOURSPERDAY;
236 		show(argv[i], t, TRUE);
237 		tm = *localtime(&t);
238 		(void) strlcpy(buf, abbr(&tm), (sizeof buf));
239 		for ( ; ; ) {
240 			if (cutoff != NULL && t >= cuttime)
241 				break;
242 			newt = t + SECSPERHOUR * 12;
243 			if (cutoff != NULL && newt >= cuttime)
244 				break;
245 			if (newt <= t)
246 				break;
247 			newtm = *localtime(&newt);
248 			if (delta(&newtm, &tm) != (newt - t) ||
249 				newtm.tm_isdst != tm.tm_isdst ||
250 				strcmp(abbr(&newtm), buf) != 0) {
251 					newt = hunt(argv[i], t, newt);
252 					newtm = *localtime(&newt);
253 					(void) strlcpy(buf, abbr(&newtm),
254 						(sizeof buf));
255 			}
256 			t = newt;
257 			tm = newtm;
258 		}
259 		/*
260 		** Get highest value of t.
261 		*/
262 		t = ~((time_t) 0);
263 		if (t < 0)		/* time_t is signed */
264 			t &= ~hibit;
265 		t -= SECSPERHOUR * HOURSPERDAY;
266 		show(argv[i], t, TRUE);
267 		t += SECSPERHOUR * HOURSPERDAY;
268 		show(argv[i], t, TRUE);
269 	}
270 	if (fflush(stdout) || ferror(stdout)) {
271 		(void) fprintf(stderr, "%s: ", argv[0]);
272 		(void) perror(_("Error writing standard output"));
273 		(void) exit(EXIT_FAILURE);
274 	}
275 	exit(EXIT_SUCCESS);
276 
277 	/* gcc -Wall pacifier */
278 	for ( ; ; )
279 		continue;
280 }
281 
282 static time_t
283 hunt(name, lot, hit)
284 char *	name;
285 time_t	lot;
286 time_t	hit;
287 {
288 	time_t		t;
289 	struct tm	lotm;
290 	struct tm	tm;
291 	static char	loab[MAX_STRING_LENGTH];
292 
293 	lotm = *localtime(&lot);
294 	(void) strlcpy(loab, abbr(&lotm), (sizeof loab));
295 	while ((hit - lot) >= 2) {
296 		t = lot / 2 + hit / 2;
297 		if (t <= lot)
298 			++t;
299 		else if (t >= hit)
300 			--t;
301 		tm = *localtime(&t);
302 		if (delta(&tm, &lotm) == (t - lot) &&
303 			tm.tm_isdst == lotm.tm_isdst &&
304 			strcmp(abbr(&tm), loab) == 0) {
305 				lot = t;
306 				lotm = tm;
307 		} else	hit = t;
308 	}
309 	show(name, lot, TRUE);
310 	show(name, hit, TRUE);
311 	return hit;
312 }
313 
314 /*
315 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
316 */
317 
318 static long
319 delta(newp, oldp)
320 struct tm *	newp;
321 struct tm *	oldp;
322 {
323 	long	result;
324 	int	tmy;
325 
326 	if (newp->tm_year < oldp->tm_year)
327 		return -delta(oldp, newp);
328 	result = 0;
329 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
330 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
331 	result += newp->tm_yday - oldp->tm_yday;
332 	result *= HOURSPERDAY;
333 	result += newp->tm_hour - oldp->tm_hour;
334 	result *= MINSPERHOUR;
335 	result += newp->tm_min - oldp->tm_min;
336 	result *= SECSPERMIN;
337 	result += newp->tm_sec - oldp->tm_sec;
338 	return result;
339 }
340 
341 static void
342 show(zone, t, v)
343 char *	zone;
344 time_t	t;
345 int	v;
346 {
347 	struct tm *	tmp;
348 
349 	(void) printf("%-*s  ", (int) longest, zone);
350 	if (v)
351 		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
352 	tmp = localtime(&t);
353 	(void) printf("%.24s", asctime(tmp));
354 	if (*abbr(tmp) != '\0')
355 		(void) printf(" %s", abbr(tmp));
356 	if (v) {
357 		(void) printf(" isdst=%d", tmp->tm_isdst);
358 #ifdef TM_GMTOFF
359 		(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
360 #endif /* defined TM_GMTOFF */
361 	}
362 	(void) printf("\n");
363 }
364 
365 static const char *
366 abbr(tmp)
367 struct tm *	tmp;
368 {
369 	register const char *	result;
370 	static const char	nada;
371 
372 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
373 		return &nada;
374 	result = tzname[tmp->tm_isdst];
375 	return (result == NULL) ? &nada : result;
376 }
377