xref: /netbsd-src/bin/date/date.c (revision bf1e9b32e27832f0c493206710fb8b58a980838a)
1 /* $NetBSD: date.c,v 1.40 2005/06/26 19:10:48 christos Exp $ */
2 
3 /*
4  * Copyright (c) 1985, 1987, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT(
35 "@(#) Copyright (c) 1985, 1987, 1988, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n");
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)date.c	8.2 (Berkeley) 4/28/95";
42 #else
43 __RCSID("$NetBSD: date.c,v 1.40 2005/06/26 19:10:48 christos Exp $");
44 #endif
45 #endif /* not lint */
46 
47 #include <sys/param.h>
48 #include <sys/time.h>
49 
50 #include <ctype.h>
51 #include <err.h>
52 #include <fcntl.h>
53 #include <locale.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <syslog.h>
58 #include <time.h>
59 #include <tzfile.h>
60 #include <unistd.h>
61 #include <util.h>
62 
63 #include "extern.h"
64 
65 static time_t tval;
66 static int aflag, rflag, nflag;
67 int retval;
68 
69 int main(int, char *[]);
70 static void badformat(void);
71 static void badtime(void);
72 static void setthetime(const char *);
73 static void usage(void);
74 
75 int
76 main(int argc, char *argv[])
77 {
78 	char buf[1024];
79 	const char *format;
80 	int ch;
81 
82 	setprogname(argv[0]);
83 	(void)setlocale(LC_ALL, "");
84 
85 	while ((ch = getopt(argc, argv, "anr:u")) != -1) {
86 		switch((char)ch) {
87 		case 'a':		/* adjust time slowly */
88 			aflag = 1;
89 			nflag = 1;
90 			break;
91 		case 'n':		/* don't set network */
92 			nflag = 1;
93 			break;
94 		case 'r':		/* user specified seconds */
95 			rflag = 1;
96 			tval = strtol(optarg, NULL, 0);
97 			break;
98 		case 'u':		/* do everything in UTC */
99 			(void)putenv("TZ=UTC0");
100 			break;
101 		default:
102 			usage();
103 		}
104 	}
105 	argc -= optind;
106 	argv += optind;
107 
108 	if (!rflag && time(&tval) == -1)
109 		err(1, "time");
110 
111 	format = "%a %b %e %H:%M:%S %Z %Y";
112 
113 	/* allow the operands in any order */
114 	if (*argv && **argv == '+') {
115 		format = *argv + 1;
116 		++argv;
117 	}
118 
119 	if (*argv) {
120 		setthetime(*argv);
121 		++argv;
122 	}
123 
124 	if (*argv && **argv == '+')
125 		format = *argv + 1;
126 
127 	(void)strftime(buf, sizeof(buf), format, localtime(&tval));
128 	(void)printf("%s\n", buf);
129 	exit(retval);
130 	/* NOTREACHED */
131 }
132 
133 static void
134 badformat(void)
135 {
136 	warnx("illegal time format");
137 	usage();
138 }
139 
140 static void
141 badtime(void)
142 {
143 	errx(EXIT_FAILURE, "illegal time");
144 	/* NOTREACHED */
145 }
146 
147 #define ATOI2(s) ((s) += 2, ((s)[-2] - '0') * 10 + ((s)[-1] - '0'))
148 
149 static void
150 setthetime(const char *p)
151 {
152 	struct timeval tv;
153 	time_t new_time;
154 	struct tm *lt;
155 	const char *dot, *t;
156 	int len, yearset;
157 
158 	for (t = p, dot = NULL; *t; ++t) {
159 		if (isdigit((unsigned char)*t))
160 			continue;
161 		if (*t == '.' && dot == NULL) {
162 			dot = t;
163 			continue;
164 		}
165 		badformat();
166 	}
167 
168 	lt = localtime(&tval);
169 
170 	lt->tm_isdst = -1;			/* Divine correct DST */
171 
172 	if (dot != NULL) {			/* .ss */
173 		len = strlen(dot);
174 		if (len != 3)
175 			badformat();
176 		++dot;
177 		lt->tm_sec = ATOI2(dot);
178 	} else {
179 		len = 0;
180 		lt->tm_sec = 0;
181 	}
182 
183 	yearset = 0;
184 	switch (strlen(p) - len) {
185 	case 12:				/* cc */
186 		lt->tm_year = ATOI2(p) * 100 - TM_YEAR_BASE;
187 		yearset = 1;
188 		/* FALLTHROUGH */
189 	case 10:				/* yy */
190 		if (yearset) {
191 			lt->tm_year += ATOI2(p);
192 		} else {
193 			yearset = ATOI2(p);
194 			if (yearset < 69)
195 				lt->tm_year = yearset + 2000 - TM_YEAR_BASE;
196 			else
197 				lt->tm_year = yearset + 1900 - TM_YEAR_BASE;
198 		}
199 		/* FALLTHROUGH */
200 	case 8:					/* mm */
201 		lt->tm_mon = ATOI2(p);
202 		--lt->tm_mon;			/* time struct is 0 - 11 */
203 		/* FALLTHROUGH */
204 	case 6:					/* dd */
205 		lt->tm_mday = ATOI2(p);
206 		/* FALLTHROUGH */
207 	case 4:					/* hh */
208 		lt->tm_hour = ATOI2(p);
209 		/* FALLTHROUGH */
210 	case 2:					/* mm */
211 		lt->tm_min = ATOI2(p);
212 		break;
213 	case 0:					/* was just .sss */
214 		if (len != 0)
215 			break;
216 		/* FALLTHROUGH */
217 	default:
218 		badformat();
219 	}
220 
221 	/* convert broken-down time to UTC clock time */
222 	if ((new_time = mktime(lt)) == -1)
223 		badtime();
224 
225 	/* set the time */
226 	if (nflag || netsettime(new_time)) {
227 		logwtmp("|", "date", "");
228 		if (aflag) {
229 			tv.tv_sec = new_time - tval;
230 			tv.tv_usec = 0;
231 			if (adjtime(&tv, NULL)) {
232 				perror("date: adjtime");
233 				exit(1);
234 			}
235 		} else {
236 			tval = new_time;
237 			tv.tv_sec = tval;
238 			tv.tv_usec = 0;
239 			if (settimeofday(&tv, NULL)) {
240 				perror("date: settimeofday");
241 				exit(1);
242 			}
243 		}
244 		logwtmp("{", "date", "");
245 	}
246 
247 	if ((p = getlogin()) == NULL)
248 		p = "???";
249 	syslog(LOG_AUTH | LOG_NOTICE, "date set by %s", p);
250 }
251 
252 static void
253 usage(void)
254 {
255 	(void)fprintf(stderr,
256 	    "usage: %s [-u] [-r seconds] [+format]\n", getprogname());
257 	(void)fprintf(stderr, "       %s [-anu] [[[[[cc]yy]mm]dd]hh]mm[.ss]\n", getprogname());
258 	exit(1);
259 	/* NOTREACHED */
260 }
261