xref: /dragonfly/usr.sbin/zic/zdump.c (revision 71126e33)
1 #ifndef lint
2 #ifndef NOID
3 static char	elsieid[] = "@(#)zdump.c	7.28";
4 #endif /* !defined NOID */
5 #endif /* !defined lint */
6 
7 /*
8  * @(#)zdump.c	7.28
9  * $FreeBSD: src/usr.sbin/zic/zdump.c,v 1.7 1999/08/28 01:21:19 peter Exp $
10  * $DragonFly: src/usr.sbin/zic/zdump.c,v 1.4 2004/12/18 22:48:15 swildner Exp $
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 <err.h>
19 #include <stdio.h>	/* for stdout, stderr */
20 #include <stdlib.h>	/* for exit, malloc, atoi */
21 #include <string.h>	/* for strcpy */
22 #include <sys/types.h>	/* for time_t */
23 #include <time.h>	/* for struct tm */
24 #include <unistd.h>
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 extern char **	environ;
122 extern char *	tzname[2];
123 
124 static char	*abbr(struct tm *tmp);
125 static long	 delta(struct tm *newp, struct tm *oldp);
126 static time_t	 hunt(char *name, time_t lot, time_t hit);
127 static size_t	 longest;
128 static char	*progname;
129 static void	 show(char *zone, time_t t, int v);
130 static void	 usage(void);
131 
132 int
133 main(int argc, char *argv[])
134 {
135 	int i;
136 	int c;
137 	int vflag;
138 	char *cutoff;
139 	int cutyear;
140 	long cuttime;
141 	char **fakeenv;
142 	time_t now;
143 	time_t t;
144 	time_t newt;
145 	time_t hibit;
146 	struct tm tm;
147 	struct tm newtm;
148 
149 	INITIALIZE(cuttime);
150 #if HAVE_GETTEXT - 0
151 	setlocale(LC_MESSAGES, "");
152 #ifdef TZ_DOMAINDIR
153 	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
154 #endif /* defined(TEXTDOMAINDIR) */
155 	textdomain(TZ_DOMAIN);
156 #endif /* HAVE_GETTEXT - 0 */
157 	vflag = 0;
158 	cutoff = NULL;
159 	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
160 		if (c == 'v')
161 			vflag = 1;
162 		else	cutoff = optarg;
163 	if ((c != EOF && c != -1) ||
164 		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
165 			usage();
166 	}
167 	if (cutoff != NULL) {
168 		int	y;
169 
170 		cutyear = atoi(cutoff);
171 		cuttime = 0;
172 		for (y = EPOCH_YEAR; y < cutyear; ++y)
173 			cuttime += DAYSPERNYEAR + isleap(y);
174 		cuttime *= SECSPERHOUR * HOURSPERDAY;
175 	}
176 	time(&now);
177 	longest = 0;
178 	for (i = optind; i < argc; ++i)
179 		if (strlen(argv[i]) > longest)
180 			longest = strlen(argv[i]);
181 	for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
182 		continue;
183 	{
184 		int from;
185 		int to;
186 
187 		for (i = 0;  environ[i] != NULL;  ++i)
188 			continue;
189 		fakeenv = (char **) malloc((size_t) ((i + 2) *
190 			sizeof *fakeenv));
191 		if (fakeenv == NULL ||
192 			(fakeenv[0] = (char *) malloc((size_t) (longest +
193 				4))) == NULL)
194 					errx(EXIT_FAILURE,
195 					     _("malloc() failed"));
196 		to = 0;
197 		strcpy(fakeenv[to++], "TZ=");
198 		for (from = 0; environ[from] != NULL; ++from)
199 			if (strncmp(environ[from], "TZ=", 3) != 0)
200 				fakeenv[to++] = environ[from];
201 		fakeenv[to] = NULL;
202 		environ = fakeenv;
203 	}
204 	for (i = optind; i < argc; ++i) {
205 		static char	buf[MAX_STRING_LENGTH];
206 
207 		strcpy(&fakeenv[0][3], argv[i]);
208 		if (!vflag) {
209 			show(argv[i], now, FALSE);
210 			continue;
211 		}
212 		/*
213 		** Get lowest value of t.
214 		*/
215 		t = hibit;
216 		if (t > 0)		/* time_t is unsigned */
217 			t = 0;
218 		show(argv[i], t, TRUE);
219 		t += SECSPERHOUR * HOURSPERDAY;
220 		show(argv[i], t, TRUE);
221 		tm = *localtime(&t);
222 		strncpy(buf, abbr(&tm), (sizeof buf) - 1);
223 		for ( ; ; ) {
224 			if (cutoff != NULL && t >= cuttime)
225 				break;
226 			newt = t + SECSPERHOUR * 12;
227 			if (cutoff != NULL && newt >= cuttime)
228 				break;
229 			if (newt <= t)
230 				break;
231 			newtm = *localtime(&newt);
232 			if (delta(&newtm, &tm) != (newt - t) ||
233 				newtm.tm_isdst != tm.tm_isdst ||
234 				strcmp(abbr(&newtm), buf) != 0) {
235 					newt = hunt(argv[i], t, newt);
236 					newtm = *localtime(&newt);
237 					strncpy(buf, abbr(&newtm),
238 						(sizeof buf) - 1);
239 			}
240 			t = newt;
241 			tm = newtm;
242 		}
243 		/*
244 		** Get highest value of t.
245 		*/
246 		t = ~((time_t) 0);
247 		if (t < 0)		/* time_t is signed */
248 			t &= ~hibit;
249 		t -= SECSPERHOUR * HOURSPERDAY;
250 		show(argv[i], t, TRUE);
251 		t += SECSPERHOUR * HOURSPERDAY;
252 		show(argv[i], t, TRUE);
253 	}
254 	if (fflush(stdout) || ferror(stdout))
255 		errx(EXIT_FAILURE, _("error writing standard output"));
256 	exit(EXIT_SUCCESS);
257 
258 	/* gcc -Wall pacifier */
259 	for ( ; ; )
260 		continue;
261 }
262 
263 static void
264 usage(void)
265 {
266 	fprintf(stderr, _("usage: zdump [-v] [-c cutoff] zonename ...\n"));
267 	exit(EXIT_FAILURE);
268 }
269 
270 static time_t
271 hunt(char *name, time_t lot, time_t hit)
272 {
273 	time_t		t;
274 	struct tm	lotm;
275 	struct tm	tm;
276 	static char	loab[MAX_STRING_LENGTH];
277 
278 	lotm = *localtime(&lot);
279 	strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
280 	while ((hit - lot) >= 2) {
281 		t = lot / 2 + hit / 2;
282 		if (t <= lot)
283 			++t;
284 		else if (t >= hit)
285 			--t;
286 		tm = *localtime(&t);
287 		if (delta(&tm, &lotm) == (t - lot) &&
288 			tm.tm_isdst == lotm.tm_isdst &&
289 			strcmp(abbr(&tm), loab) == 0) {
290 				lot = t;
291 				lotm = tm;
292 		} else	hit = t;
293 	}
294 	show(name, lot, TRUE);
295 	show(name, hit, TRUE);
296 	return hit;
297 }
298 
299 /*
300 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
301 */
302 
303 static long
304 delta(struct tm *newp, struct tm *oldp)
305 {
306 	long	result;
307 	int	tmy;
308 
309 	if (newp->tm_year < oldp->tm_year)
310 		return -delta(oldp, newp);
311 	result = 0;
312 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
313 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
314 	result += newp->tm_yday - oldp->tm_yday;
315 	result *= HOURSPERDAY;
316 	result += newp->tm_hour - oldp->tm_hour;
317 	result *= MINSPERHOUR;
318 	result += newp->tm_min - oldp->tm_min;
319 	result *= SECSPERMIN;
320 	result += newp->tm_sec - oldp->tm_sec;
321 	return result;
322 }
323 
324 static void
325 show(char *zone, time_t t, int v)
326 {
327 	struct tm *	tmp;
328 
329 	printf("%-*s  ", (int) longest, zone);
330 	if (v)
331 		printf("%.24s UTC = ", asctime(gmtime(&t)));
332 	tmp = localtime(&t);
333 	printf("%.24s", asctime(tmp));
334 	if (*abbr(tmp) != '\0')
335 		printf(" %s", abbr(tmp));
336 	if (v) {
337 		printf(" isdst=%d", tmp->tm_isdst);
338 #ifdef TM_GMTOFF
339 		printf(" gmtoff=%ld", tmp->TM_GMTOFF);
340 #endif /* defined TM_GMTOFF */
341 	}
342 	printf("\n");
343 }
344 
345 static char *
346 abbr(struct tm *tmp)
347 {
348 	char * result;
349 	static char nada;
350 
351 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
352 		return &nada;
353 	result = tzname[tmp->tm_isdst];
354 	return (result == NULL) ? &nada : result;
355 }
356