xref: /titanic_50/usr/src/lib/libc/port/locale/getdate.c (revision a154f012db8e83f5f1b49be92c91827d1868a12a)
1 /*
2  * Copyright (c) 2009 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Brian Ginsbach.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 /*
31  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
32  * Use is subject to license terms.
33  */
34 
35 #include "lint.h"
36 #include "file64.h"
37 #include <sys/types.h>
38 #include <errno.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <time.h>
43 #include <unistd.h>
44 #include <sys/stat.h>
45 
46 #define	TMSENTINEL	(-1)
47 
48 
49 /*
50  * getdate_err is set to one of the following values on error.
51  *
52  * 1	The DATEMSK environment variable is null or undefined.
53  * 2	The template file cannot be opened for reading.
54  * 3	Failed to get file status information.
55  * 4	Template file is not a regular file.
56  * 5	Encountered an error while reading the template file.
57  * 6	Cannot allocate memory.
58  * 7	Input string does not match any line in the template.
59  * 8	Input string is invalid (for example, February 31) or could not
60  *	be represented in a time_t.
61  *
62  * Note that on Solaris, getdate_err is possibly a function, to account
63  * for reentrancy.  See the code for getdate_err.c for details.
64  */
65 
66 
67 #pragma	weak	_getdate = getdate
68 struct tm *
69 getdate(const char *str)
70 {
71 	char *datemsk, *line, *rp;
72 	FILE *fp;
73 	struct stat sb;
74 	static struct tm rtm, tmnow;
75 	struct tm *tmp, *rtmp = &rtm;
76 	time_t now;
77 	char buf[514];
78 
79 	if (((datemsk = getenv("DATEMSK")) == NULL) || *datemsk == '\0') {
80 		getdate_err = 1;
81 		return (NULL);
82 	}
83 
84 	if (stat(datemsk, &sb) < 0) {
85 		getdate_err = 3;
86 		return (NULL);
87 	}
88 
89 	if ((sb.st_mode & S_IFMT) != S_IFREG) {
90 		getdate_err = 4;
91 		return (NULL);
92 	}
93 
94 	if ((fp = fopen(datemsk, "r")) == NULL) {
95 		getdate_err = 2;
96 		return (NULL);
97 	}
98 
99 	/* loop through datemsk file */
100 	errno = 0;
101 	rp = NULL;
102 
103 	/*
104 	 * The NetBSD implementation supports a rich flexible file format
105 	 * with embedded escapes, etc.  We don't need any of that.  Solaris
106 	 * just reads the template file and (undocumented!) requires that
107 	 * each line not exceed 512 bytes, using a fixed buffer.   We could
108 	 * improve on that, but this may grow the stack unreasonably, so
109 	 * we keep it to the same 512 limit.  Some day we can be smarter.
110 	 * (Note FreeBSD doesn't even have getdate(), and IMO nobody sane
111 	 * should be using this crufty API.  strptime is better.)
112 	 */
113 
114 	(void) memset(buf, 0, sizeof (buf));
115 	while ((line = fgets(buf, sizeof (buf), fp)) != NULL) {
116 		/*
117 		 * If the buffer consumed the entire string, then
118 		 * the input line was too long.  We just check to
119 		 * see if the 2nd to last byte is set.  If it isn't,
120 		 * then we hit a null byte first, and the line is
121 		 * short enough.
122 		 */
123 		if (buf[sizeof (buf) - 2] != 0) {
124 			getdate_err = 5;
125 			(void) fclose(fp);
126 			return (NULL);
127 		}
128 		/* initialize tmp with sentinels */
129 		rtm.tm_sec = rtm.tm_min = rtm.tm_hour = TMSENTINEL;
130 		rtm.tm_mday = rtm.tm_mon = rtm.tm_year = TMSENTINEL;
131 		rtm.tm_wday = rtm.tm_yday = rtm.tm_isdst = TMSENTINEL;
132 		rp = strptime(str, line, rtmp);
133 		if (rp != NULL)
134 			break;
135 		errno = 0;
136 	}
137 	if (errno != 0 || ferror(fp)) {
138 		if (errno == ENOMEM)
139 			getdate_err = 6;
140 		else
141 			getdate_err = 5;
142 		(void) fclose(fp);
143 		return (NULL);
144 	}
145 	if (feof(fp) || (rp != NULL && *rp != '\0')) {
146 		getdate_err = 7;
147 		return (NULL);
148 	}
149 	(void) fclose(fp);
150 
151 	(void) time(&now);
152 	tmp = localtime(&now);
153 	tmnow = *tmp;
154 
155 	/*
156 	 * This implementation does not accept setting the broken-down time
157 	 * to anything other than the localtime().  It is not possible to
158 	 * change the scanned timezone with %Z.
159 	 *
160 	 * Note IRIX and Solaris accept only the current zone for %Z.
161 	 * XXX Is there any implementation that matches the standard?
162 	 * XXX (Or am I reading the standard wrong?)
163 	 *
164 	 * Note: Neither XPG 6 (POSIX 2004) nor XPG 7 (POSIX 2008)
165 	 * requires strptime(3) support for %Z.
166 	 */
167 
168 	/*
169 	 * Given only a weekday find the first matching weekday starting
170 	 * with the current weekday and moving into the future.
171 	 */
172 	if (rtm.tm_wday != TMSENTINEL && rtm.tm_year == TMSENTINEL &&
173 	    rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
174 		rtm.tm_year = tmnow.tm_year;
175 		rtm.tm_mon = tmnow.tm_mon;
176 		rtm.tm_mday = tmnow.tm_mday +
177 		    (rtm.tm_wday - tmnow.tm_wday + 7) % 7;
178 	}
179 
180 	/*
181 	 * Given only a month (and no year) find the first matching month
182 	 * starting with the current month and moving into the future.
183 	 */
184 	if (rtm.tm_mon != TMSENTINEL) {
185 		if (rtm.tm_year == TMSENTINEL) {
186 			rtm.tm_year = tmnow.tm_year +
187 			    ((rtm.tm_mon < tmnow.tm_mon)? 1 : 0);
188 		}
189 		if (rtm.tm_mday == TMSENTINEL) {
190 			/* assume the first of the month */
191 			rtm.tm_mday = 1;
192 			/*
193 			 * XXX This isn't documented! Just observed behavior.
194 			 *
195 			 * Given the weekday find the first matching weekday
196 			 * starting with the weekday of the first day of the
197 			 * the month and moving into the future.
198 			 */
199 			if (rtm.tm_wday != TMSENTINEL) {
200 				struct tm tm;
201 
202 				(void) memset(&tm, 0, sizeof (struct tm));
203 				tm.tm_year = rtm.tm_year;
204 				tm.tm_mon = rtm.tm_mon;
205 				tm.tm_mday = 1;
206 				(void) mktime(&tm);
207 				rtm.tm_mday +=
208 				    (rtm.tm_wday - tm.tm_wday + 7) % 7;
209 			}
210 		}
211 	}
212 
213 	/*
214 	 * Given no time of day assume the current time of day.
215 	 */
216 	if (rtm.tm_hour == TMSENTINEL &&
217 	    rtm.tm_min == TMSENTINEL && rtm.tm_sec == TMSENTINEL) {
218 		rtm.tm_hour = tmnow.tm_hour;
219 		rtm.tm_min = tmnow.tm_min;
220 		rtm.tm_sec = tmnow.tm_sec;
221 	}
222 	/*
223 	 * Given an hour and no date, find the first matching hour starting
224 	 * with the current hour and moving into the future
225 	 */
226 	if (rtm.tm_hour != TMSENTINEL &&
227 	    rtm.tm_year == TMSENTINEL && rtm.tm_mon == TMSENTINEL &&
228 	    rtm.tm_mday == TMSENTINEL) {
229 		rtm.tm_year = tmnow.tm_year;
230 		rtm.tm_mon = tmnow.tm_mon;
231 		rtm.tm_mday = tmnow.tm_mday;
232 		if (rtm.tm_hour < tmnow.tm_hour)
233 			rtm.tm_hour += 24;
234 	}
235 
236 	/*
237 	 * Set to 'sane' values; mktime(3) does funny things otherwise.
238 	 * No hours, no minutes, no seconds, no service.
239 	 */
240 	if (rtm.tm_hour == TMSENTINEL)
241 		rtm.tm_hour = 0;
242 	if (rtm.tm_min == TMSENTINEL)
243 		rtm.tm_min = 0;
244 	if (rtm.tm_sec == TMSENTINEL)
245 		rtm.tm_sec = 0;
246 
247 	/*
248 	 * Given only a year the values of month, day of month, day of year,
249 	 * week day and is daylight (summer) time are unspecified.
250 	 * (Specified on the Solaris man page not POSIX.)
251 	 */
252 	if (rtm.tm_year != TMSENTINEL &&
253 	    rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
254 		rtm.tm_mon = 0;
255 		rtm.tm_mday = 1;
256 		/*
257 		 * XXX More undocumented functionality but observed.
258 		 *
259 		 * Given the weekday find the first matching weekday
260 		 * starting with the weekday of the first day of the
261 		 * month and moving into the future.
262 		 */
263 		if (rtm.tm_wday != TMSENTINEL) {
264 			struct tm tm;
265 
266 			(void) memset(&tm, 0, sizeof (struct tm));
267 			tm.tm_year = rtm.tm_year;
268 			tm.tm_mon = rtm.tm_mon;
269 			tm.tm_mday = 1;
270 			(void) mktime(&tm);
271 			rtm.tm_mday += (rtm.tm_wday - tm.tm_wday + 7) % 7;
272 		}
273 	}
274 
275 	/*
276 	 * Given only the century but no year within, the current year
277 	 * is assumed.  (Specified on the Solaris man page not POSIX.)
278 	 *
279 	 * Warning ugly end case
280 	 *
281 	 * This is more work since strptime(3) doesn't "do the right thing".
282 	 */
283 	if (rtm.tm_year != TMSENTINEL && (rtm.tm_year - 1900) >= 0) {
284 		rtm.tm_year -= 1900;
285 		rtm.tm_year += (tmnow.tm_year % 100);
286 	}
287 
288 	/*
289 	 * mktime() will normalize all values and also check that the
290 	 * value will fit into a time_t.
291 	 *
292 	 * This is only for POSIX correctness.	A date >= 1900 is
293 	 * really ok, but using a time_t limits things.
294 	 */
295 	if (mktime(rtmp) < 0) {
296 		getdate_err = 8;
297 		return (NULL);
298 	}
299 
300 	return (rtmp);
301 }
302