xref: /netbsd-src/lib/libc/time/zdump.c (revision 817cd315412cb2ce0bc4e6bf3f12a866fd948396)
1 /*	$NetBSD: zdump.c,v 1.16 2006/12/04 17:24:40 kleink Exp $	*/
2 
3 #include <sys/cdefs.h>
4 #ifndef lint
5 #ifndef NOID
6 __RCSID("$NetBSD: zdump.c,v 1.16 2006/12/04 17:24:40 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 */
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 #include <err.h>
24 
25 #ifndef MAX_STRING_LENGTH
26 #define MAX_STRING_LENGTH	1024
27 #endif /* !defined MAX_STRING_LENGTH */
28 
29 #ifndef TRUE
30 #define TRUE		1
31 #endif /* !defined TRUE */
32 
33 #ifndef FALSE
34 #define FALSE		0
35 #endif /* !defined FALSE */
36 
37 #ifndef EXIT_SUCCESS
38 #define EXIT_SUCCESS	0
39 #endif /* !defined EXIT_SUCCESS */
40 
41 #ifndef EXIT_FAILURE
42 #define EXIT_FAILURE	1
43 #endif /* !defined EXIT_FAILURE */
44 
45 #ifndef SECSPERMIN
46 #define SECSPERMIN	60
47 #endif /* !defined SECSPERMIN */
48 
49 #ifndef MINSPERHOUR
50 #define MINSPERHOUR	60
51 #endif /* !defined MINSPERHOUR */
52 
53 #ifndef SECSPERHOUR
54 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
55 #endif /* !defined SECSPERHOUR */
56 
57 #ifndef HOURSPERDAY
58 #define HOURSPERDAY	24
59 #endif /* !defined HOURSPERDAY */
60 
61 #ifndef EPOCH_YEAR
62 #define EPOCH_YEAR	1970
63 #endif /* !defined EPOCH_YEAR */
64 
65 #ifndef TM_YEAR_BASE
66 #define TM_YEAR_BASE	1900
67 #endif /* !defined TM_YEAR_BASE */
68 
69 #ifndef DAYSPERNYEAR
70 #define DAYSPERNYEAR	365
71 #endif /* !defined DAYSPERNYEAR */
72 
73 #ifndef isleap
74 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
75 #endif /* !defined isleap */
76 
77 #if HAVE_GETTEXT - 0
78 #include "locale.h"	/* for setlocale */
79 #include "libintl.h"
80 #endif /* HAVE_GETTEXT - 0 */
81 
82 #ifndef GNUC_or_lint
83 #ifdef lint
84 #define GNUC_or_lint
85 #endif /* defined lint */
86 #ifndef lint
87 #ifdef __GNUC__
88 #define GNUC_or_lint
89 #endif /* defined __GNUC__ */
90 #endif /* !defined lint */
91 #endif /* !defined GNUC_or_lint */
92 
93 #ifndef INITIALIZE
94 #ifdef GNUC_or_lint
95 #define INITIALIZE(x)	((x) = 0)
96 #endif /* defined GNUC_or_lint */
97 #ifndef GNUC_or_lint
98 #define INITIALIZE(x)
99 #endif /* !defined GNUC_or_lint */
100 #endif /* !defined INITIALIZE */
101 
102 /*
103 ** For the benefit of GNU folk...
104 ** `_(MSGID)' uses the current locale's message library string for MSGID.
105 ** The default is to use gettext if available, and use MSGID otherwise.
106 */
107 
108 #ifndef _
109 #if HAVE_GETTEXT - 0
110 #define _(msgid) gettext(msgid)
111 #else /* !(HAVE_GETTEXT - 0) */
112 #define _(msgid) msgid
113 #endif /* !(HAVE_GETTEXT - 0) */
114 #endif /* !defined _ */
115 
116 #ifndef TZ_DOMAIN
117 #define TZ_DOMAIN "tz"
118 #endif /* !defined TZ_DOMAIN */
119 
120 #ifndef P
121 #define P(x)	x
122 #endif /* !defined P */
123 
124 extern char **	environ;
125 extern int	getopt P((int argc, char * const argv[],
126 			  const char * options));
127 extern char *	optarg;
128 extern int	optind;
129 
130 static const char *	abbr P((struct tm * tmp));
131 static long	delta P((struct tm * newp, struct tm * oldp));
132 static time_t	hunt P((char * name, time_t lot, time_t	hit));
133 int		main P((int, char **));
134 static size_t	longest;
135 static char *	progname;
136 static void	show P((char * zone, time_t t, int v));
137 
138 int
139 main(argc, argv)
140 int	argc;
141 char *	argv[];
142 {
143 	register int		i;
144 	register int		c;
145 	register int		vflag;
146 	register char *		cutoff;
147 	register int		cutyear;
148 	register long		cuttime;
149 	char **			fakeenv;
150 	time_t			now;
151 	time_t			t;
152 	time_t			newt;
153 	time_t			hibit;
154 	struct tm		tm;
155 	struct tm		newtm;
156 
157 	INITIALIZE(cuttime);
158 #if HAVE_GETTEXT - 0
159 	(void) setlocale(LC_MESSAGES, "");
160 #ifdef TZ_DOMAINDIR
161 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
162 #endif /* defined(TEXTDOMAINDIR) */
163 	(void) textdomain(TZ_DOMAIN);
164 #endif /* HAVE_GETTEXT - 0 */
165 	progname = argv[0];
166 	for (i = 1; i < argc; ++i)
167 		if (strcmp(argv[i], "--version") == 0) {
168 			(void) printf("%s\n", elsieid);
169 			(void) exit(EXIT_SUCCESS);
170 		}
171 	vflag = 0;
172 	cutoff = NULL;
173 	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
174 		if (c == 'v')
175 			vflag = 1;
176 		else	cutoff = optarg;
177 	if ((c != EOF && c != -1) ||
178 		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
179 			(void) fprintf(stderr,
180 _("%s: usage is %s [ --version ] [ -v ] [ -c cutoff ] zonename ...\n"),
181 				argv[0], argv[0]);
182 			(void) exit(EXIT_FAILURE);
183 	}
184 	if (cutoff != NULL) {
185 		int	y;
186 
187 		cutyear = atoi(cutoff);
188 		cuttime = 0;
189 		for (y = EPOCH_YEAR; y < cutyear; ++y)
190 			cuttime += DAYSPERNYEAR + isleap(y);
191 		cuttime *= SECSPERHOUR * HOURSPERDAY;
192 	}
193 	(void) time(&now);
194 	longest = 0;
195 	for (i = optind; i < argc; ++i)
196 		if (strlen(argv[i]) > longest)
197 			longest = strlen(argv[i]);
198 	for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
199 		continue;
200 	{
201 		register int	from;
202 		register int	to;
203 
204 		for (i = 0;  environ[i] != NULL;  ++i)
205 			continue;
206 		fakeenv = (char **) malloc((size_t) ((i + 2) *
207 			sizeof *fakeenv));
208 		if (fakeenv == NULL ||
209 			(fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
210 			err(EXIT_FAILURE, "Can't allocated %zu bytes",
211 			    longest + 4);
212 		}
213 		to = 0;
214 		(void)strcpy(fakeenv[to++], "TZ=");	/* XXX strcpy is safe */
215 		for (from = 0; environ[from] != NULL; ++from)
216 			if (strncmp(environ[from], "TZ=", 3) != 0)
217 				fakeenv[to++] = environ[from];
218 		fakeenv[to] = NULL;
219 		environ = fakeenv;
220 	}
221 	for (i = optind; i < argc; ++i) {
222 		static char	buf[MAX_STRING_LENGTH];
223 
224 		(void) strcpy(&fakeenv[0][3], argv[i]);	/* XXX strcpy is safe */
225 		if (!vflag) {
226 			show(argv[i], now, FALSE);
227 			continue;
228 		}
229 		/*
230 		** Get lowest value of t.
231 		*/
232 		t = hibit;
233 		if (t > 0)		/* time_t is unsigned */
234 			t = 0;
235 		show(argv[i], t, TRUE);
236 		t += SECSPERHOUR * HOURSPERDAY;
237 		show(argv[i], t, TRUE);
238 		tm = *localtime(&t);
239 		(void) strlcpy(buf, abbr(&tm), (sizeof buf));
240 		for ( ; ; ) {
241 			if (cutoff != NULL && t >= cuttime)
242 				break;
243 			newt = t + SECSPERHOUR * 12;
244 			if (cutoff != NULL && newt >= cuttime)
245 				break;
246 			if (newt <= t)
247 				break;
248 			newtm = *localtime(&newt);
249 			if (delta(&newtm, &tm) != (newt - t) ||
250 				newtm.tm_isdst != tm.tm_isdst ||
251 				strcmp(abbr(&newtm), buf) != 0) {
252 					newt = hunt(argv[i], t, newt);
253 					newtm = *localtime(&newt);
254 					(void) strlcpy(buf, abbr(&newtm),
255 						(sizeof buf));
256 			}
257 			t = newt;
258 			tm = newtm;
259 		}
260 		/*
261 		** Get highest value of t.
262 		*/
263 		t = ~((time_t) 0);
264 		if (t < 0)		/* time_t is signed */
265 			t &= ~hibit;
266 		t -= SECSPERHOUR * HOURSPERDAY;
267 		show(argv[i], t, TRUE);
268 		t += SECSPERHOUR * HOURSPERDAY;
269 		show(argv[i], t, TRUE);
270 	}
271 	if (fflush(stdout) || ferror(stdout)) {
272 		err(EXIT_FAILURE, _("Error writing standard output"));
273 	}
274 	exit(EXIT_SUCCESS);
275 
276 	/* gcc -Wall pacifier */
277 	for ( ; ; )
278 		continue;
279 }
280 
281 static time_t
282 hunt(name, lot, hit)
283 char *	name;
284 time_t	lot;
285 time_t	hit;
286 {
287 	time_t		t;
288 	struct tm	lotm;
289 	struct tm	tm;
290 	static char	loab[MAX_STRING_LENGTH];
291 
292 	lotm = *localtime(&lot);
293 	(void) strlcpy(loab, abbr(&lotm), (sizeof loab));
294 	while ((hit - lot) >= 2) {
295 		t = lot / 2 + hit / 2;
296 		if (t <= lot)
297 			++t;
298 		else if (t >= hit)
299 			--t;
300 		tm = *localtime(&t);
301 		if (delta(&tm, &lotm) == (t - lot) &&
302 			tm.tm_isdst == lotm.tm_isdst &&
303 			strcmp(abbr(&tm), loab) == 0) {
304 				lot = t;
305 				lotm = tm;
306 		} else	hit = t;
307 	}
308 	show(name, lot, TRUE);
309 	show(name, hit, TRUE);
310 	return hit;
311 }
312 
313 /*
314 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
315 */
316 
317 static long
318 delta(newp, oldp)
319 struct tm *	newp;
320 struct tm *	oldp;
321 {
322 	long	result;
323 	int	tmy;
324 
325 	if (newp->tm_year < oldp->tm_year)
326 		return -delta(oldp, newp);
327 	result = 0;
328 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
329 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
330 	result += newp->tm_yday - oldp->tm_yday;
331 	result *= HOURSPERDAY;
332 	result += newp->tm_hour - oldp->tm_hour;
333 	result *= MINSPERHOUR;
334 	result += newp->tm_min - oldp->tm_min;
335 	result *= SECSPERMIN;
336 	result += newp->tm_sec - oldp->tm_sec;
337 	return result;
338 }
339 
340 static void
341 show(zone, t, v)
342 char *	zone;
343 time_t	t;
344 int	v;
345 {
346 	struct tm *	tmp;
347 
348 	(void) printf("%-*s  ", (int) longest, zone);
349 	if (v)
350 		(void) printf("%.24s UTC = ", asctime(gmtime(&t)));
351 	tmp = localtime(&t);
352 	(void) printf("%.24s", asctime(tmp));
353 	if (*abbr(tmp) != '\0')
354 		(void) printf(" %s", abbr(tmp));
355 	if (v) {
356 		(void) printf(" isdst=%d", tmp->tm_isdst);
357 #ifdef TM_GMTOFF
358 		(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
359 #endif /* defined TM_GMTOFF */
360 	}
361 	(void) printf("\n");
362 }
363 
364 static const char *
365 abbr(tmp)
366 struct tm *	tmp;
367 {
368 	register const char *	result;
369 	static const char	nada;
370 
371 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
372 		return &nada;
373 	result = tzname[tmp->tm_isdst];
374 	return (result == NULL) ? &nada : result;
375 }
376