xref: /illumos-gate/usr/src/lib/libc/port/locale/getdate.c (revision 3ce5372277f4657ad0e52d36c979527c4ca22de2)
1 /*
2  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
3  * Copyright (c) 2009 The NetBSD Foundation, Inc.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Brian Ginsbach.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include "lint.h"
32 #include "file64.h"
33 #include <sys/types.h>
34 #include <errno.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <time.h>
39 #include <unistd.h>
40 #include <sys/stat.h>
41 
42 #define	TMSENTINEL	(-1)
43 
44 
45 /*
46  * getdate_err is set to one of the following values on error.
47  *
48  * 1	The DATEMSK environment variable is null or undefined.
49  * 2	The template file cannot be opened for reading.
50  * 3	Failed to get file status information.
51  * 4	Template file is not a regular file.
52  * 5	Encountered an error while reading the template file.
53  * 6	Cannot allocate memory.
54  * 7	Input string does not match any line in the template.
55  * 8	Input string is invalid (for example, February 31) or could not
56  *	be represented in a time_t.
57  *
58  * Note that on Solaris, getdate_err is possibly a function, to account
59  * for reentrancy.  See the code for getdate_err.c for details.
60  */
61 
62 
63 #pragma	weak	_getdate = getdate
64 struct tm *
65 getdate(const char *str)
66 {
67 	char *datemsk, *line, *rp;
68 	FILE *fp;
69 	struct stat sb;
70 	static struct tm rtm, tmnow;
71 	struct tm *tmp, *rtmp = &rtm;
72 	time_t now;
73 	char buf[514];
74 
75 	if (((datemsk = getenv("DATEMSK")) == NULL) || *datemsk == '\0') {
76 		getdate_err = 1;
77 		return (NULL);
78 	}
79 
80 	if (stat(datemsk, &sb) < 0) {
81 		getdate_err = 3;
82 		return (NULL);
83 	}
84 
85 	if ((sb.st_mode & S_IFMT) != S_IFREG) {
86 		getdate_err = 4;
87 		return (NULL);
88 	}
89 
90 	if ((fp = fopen(datemsk, "r")) == NULL) {
91 		getdate_err = 2;
92 		return (NULL);
93 	}
94 
95 	/* loop through datemsk file */
96 	errno = 0;
97 	rp = NULL;
98 
99 	/*
100 	 * The NetBSD implementation supports a rich flexible file format
101 	 * with embedded escapes, etc.  We don't need any of that.  Solaris
102 	 * just reads the template file and (undocumented!) requires that
103 	 * each line not exceed 512 bytes, using a fixed buffer.   We could
104 	 * improve on that, but this may grow the stack unreasonably, so
105 	 * we keep it to the same 512 limit.  Some day we can be smarter.
106 	 * (Note FreeBSD doesn't even have getdate(), and IMO nobody sane
107 	 * should be using this crufty API.  strptime is better.)
108 	 */
109 
110 	(void) memset(buf, 0, sizeof (buf));
111 	while ((line = fgets(buf, sizeof (buf), fp)) != NULL) {
112 		/*
113 		 * If the buffer consumed the entire string, then
114 		 * the input line was too long.  We just check to
115 		 * see if the 2nd to last byte is set.  If it isn't,
116 		 * then we hit a null byte first, and the line is
117 		 * short enough.
118 		 */
119 		if (buf[sizeof (buf) - 2] != 0) {
120 			getdate_err = 5;
121 			(void) fclose(fp);
122 			return (NULL);
123 		}
124 		/* initialize tmp with sentinels */
125 		rtm.tm_sec = rtm.tm_min = rtm.tm_hour = TMSENTINEL;
126 		rtm.tm_mday = rtm.tm_mon = rtm.tm_year = TMSENTINEL;
127 		rtm.tm_wday = rtm.tm_yday = rtm.tm_isdst = TMSENTINEL;
128 		rp = strptime(str, line, rtmp);
129 		if (rp != NULL)
130 			break;
131 		errno = 0;
132 	}
133 	if (errno != 0 || ferror(fp)) {
134 		if (errno == ENOMEM)
135 			getdate_err = 6;
136 		else
137 			getdate_err = 5;
138 		(void) fclose(fp);
139 		return (NULL);
140 	}
141 	if (feof(fp) || (rp != NULL && *rp != '\0')) {
142 		getdate_err = 7;
143 		return (NULL);
144 	}
145 	(void) fclose(fp);
146 
147 	(void) time(&now);
148 	tmp = localtime(&now);
149 	tmnow = *tmp;
150 
151 	/*
152 	 * This implementation does not accept setting the broken-down time
153 	 * to anything other than the localtime().  It is not possible to
154 	 * change the scanned timezone with %Z.
155 	 *
156 	 * Note IRIX and Solaris accept only the current zone for %Z.
157 	 * XXX Is there any implementation that matches the standard?
158 	 * XXX (Or am I reading the standard wrong?)
159 	 *
160 	 * Note: Neither XPG 6 (POSIX 2004) nor XPG 7 (POSIX 2008)
161 	 * requires strptime(3) support for %Z.
162 	 */
163 
164 	/*
165 	 * Given only a weekday find the first matching weekday starting
166 	 * with the current weekday and moving into the future.
167 	 */
168 	if (rtm.tm_wday != TMSENTINEL && rtm.tm_year == TMSENTINEL &&
169 	    rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
170 		rtm.tm_year = tmnow.tm_year;
171 		rtm.tm_mon = tmnow.tm_mon;
172 		rtm.tm_mday = tmnow.tm_mday +
173 		    (rtm.tm_wday - tmnow.tm_wday + 7) % 7;
174 	}
175 
176 	/*
177 	 * Given only a month (and no year) find the first matching month
178 	 * starting with the current month and moving into the future.
179 	 */
180 	if (rtm.tm_mon != TMSENTINEL) {
181 		if (rtm.tm_year == TMSENTINEL) {
182 			rtm.tm_year = tmnow.tm_year +
183 			    ((rtm.tm_mon < tmnow.tm_mon)? 1 : 0);
184 		}
185 		if (rtm.tm_mday == TMSENTINEL) {
186 			/* assume the first of the month */
187 			rtm.tm_mday = 1;
188 			/*
189 			 * XXX This isn't documented! Just observed behavior.
190 			 *
191 			 * Given the weekday find the first matching weekday
192 			 * starting with the weekday of the first day of the
193 			 * the month and moving into the future.
194 			 */
195 			if (rtm.tm_wday != TMSENTINEL) {
196 				struct tm tm;
197 
198 				(void) memset(&tm, 0, sizeof (struct tm));
199 				tm.tm_year = rtm.tm_year;
200 				tm.tm_mon = rtm.tm_mon;
201 				tm.tm_mday = 1;
202 				(void) mktime(&tm);
203 				rtm.tm_mday +=
204 				    (rtm.tm_wday - tm.tm_wday + 7) % 7;
205 			}
206 		}
207 	}
208 
209 	/*
210 	 * Given no time of day assume the current time of day.
211 	 */
212 	if (rtm.tm_hour == TMSENTINEL &&
213 	    rtm.tm_min == TMSENTINEL && rtm.tm_sec == TMSENTINEL) {
214 		rtm.tm_hour = tmnow.tm_hour;
215 		rtm.tm_min = tmnow.tm_min;
216 		rtm.tm_sec = tmnow.tm_sec;
217 	}
218 	/*
219 	 * Given an hour and no date, find the first matching hour starting
220 	 * with the current hour and moving into the future
221 	 */
222 	if (rtm.tm_hour != TMSENTINEL &&
223 	    rtm.tm_year == TMSENTINEL && rtm.tm_mon == TMSENTINEL &&
224 	    rtm.tm_mday == TMSENTINEL) {
225 		rtm.tm_year = tmnow.tm_year;
226 		rtm.tm_mon = tmnow.tm_mon;
227 		rtm.tm_mday = tmnow.tm_mday;
228 		if (rtm.tm_hour < tmnow.tm_hour)
229 			rtm.tm_hour += 24;
230 	}
231 
232 	/*
233 	 * Set to 'sane' values; mktime(3) does funny things otherwise.
234 	 * No hours, no minutes, no seconds, no service.
235 	 */
236 	if (rtm.tm_hour == TMSENTINEL)
237 		rtm.tm_hour = 0;
238 	if (rtm.tm_min == TMSENTINEL)
239 		rtm.tm_min = 0;
240 	if (rtm.tm_sec == TMSENTINEL)
241 		rtm.tm_sec = 0;
242 
243 	/*
244 	 * Given only a year the values of month, day of month, day of year,
245 	 * week day and is daylight (summer) time are unspecified.
246 	 * (Specified on the Solaris man page not POSIX.)
247 	 */
248 	if (rtm.tm_year != TMSENTINEL &&
249 	    rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
250 		rtm.tm_mon = 0;
251 		rtm.tm_mday = 1;
252 		/*
253 		 * XXX More undocumented functionality but observed.
254 		 *
255 		 * Given the weekday find the first matching weekday
256 		 * starting with the weekday of the first day of the
257 		 * month and moving into the future.
258 		 */
259 		if (rtm.tm_wday != TMSENTINEL) {
260 			struct tm tm;
261 
262 			(void) memset(&tm, 0, sizeof (struct tm));
263 			tm.tm_year = rtm.tm_year;
264 			tm.tm_mon = rtm.tm_mon;
265 			tm.tm_mday = 1;
266 			(void) mktime(&tm);
267 			rtm.tm_mday += (rtm.tm_wday - tm.tm_wday + 7) % 7;
268 		}
269 	}
270 
271 	/*
272 	 * Given only the century but no year within, the current year
273 	 * is assumed.  (Specified on the Solaris man page not POSIX.)
274 	 *
275 	 * Warning ugly end case
276 	 *
277 	 * This is more work since strptime(3) doesn't "do the right thing".
278 	 */
279 	if (rtm.tm_year != TMSENTINEL && (rtm.tm_year - 1900) >= 0) {
280 		rtm.tm_year -= 1900;
281 		rtm.tm_year += (tmnow.tm_year % 100);
282 	}
283 
284 	/*
285 	 * mktime() will normalize all values and also check that the
286 	 * value will fit into a time_t.
287 	 *
288 	 * This is only for POSIX correctness.	A date >= 1900 is
289 	 * really ok, but using a time_t limits things.
290 	 */
291 	if (mktime(rtmp) < 0) {
292 		getdate_err = 8;
293 		return (NULL);
294 	}
295 
296 	return (rtmp);
297 }
298