libc: Bring in getdate() from NetBSD for POSIX conformance.
[dragonfly.git] / lib / libc / stdtime / getdate.c
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28bfdfe6
SW
1/* $NetBSD: getdate.c,v 1.4 2018/01/04 20:57:29 kamil Exp $ */
2/*
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 "namespace.h"
32
33#include <sys/stat.h>
34
35#include <errno.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <time.h>
40#include <unistd.h>
41#include <util.h>
42
43#include "un-namespace.h"
44
45#define TMSENTINEL (-1)
46
47/*
48 * getdate_err is set to one of the following values on error.
49 *
50 * 1 The DATEMSK environment variable is null or undefined.
51 * 2 The template file cannot be opened for reading.
52 * 3 Failed to get file status information.
53 * 4 Template file is not a regular file.
54 * 5 Encountered an error while reading the template file.
55 * 6 Cannot allocate memory.
56 * 7 Input string does not match any line in the template.
57 * 8 Input string is invalid (for example, February 31) or could not
58 * be represented in a time_t.
59 */
60
61int getdate_err;
62
63struct tm *
64getdate(const char *str)
65{
66 char *datemsk, *line, *rp;
67 FILE *fp;
68 struct stat sb;
69 static struct tm rtm, tmnow;
70 struct tm *tmp, *rtmp = &rtm;
71 size_t lineno = 0;
72 time_t now;
73
74 if (((datemsk = getenv("DATEMSK")) == NULL) || *datemsk == '\0') {
75 getdate_err = 1;
76 return (NULL);
77 }
78
79 if (stat(datemsk, &sb) < 0) {
80 getdate_err = 3;
81 return (NULL);
82 }
83
84 if ((sb.st_mode & S_IFMT) != S_IFREG) {
85 getdate_err = 4;
86 return (NULL);
87 }
88
89 if ((fp = fopen(datemsk, "re")) == NULL) {
90 getdate_err = 2;
91 return (NULL);
92 }
93
94 /* loop through datemsk file */
95 errno = 0;
96 rp = NULL;
97 while ((line = fparseln(fp, NULL, &lineno, NULL, 0)) != NULL) {
98 /* initialize tmp with sentinels */
99 rtm.tm_sec = rtm.tm_min = rtm.tm_hour = TMSENTINEL;
100 rtm.tm_mday = rtm.tm_mon = rtm.tm_year = TMSENTINEL;
101 rtm.tm_wday = rtm.tm_yday = rtm.tm_isdst = TMSENTINEL;
102 rtm.tm_gmtoff = 0;
103 rtm.tm_zone = NULL;
104 rp = strptime(str, line, rtmp);
105 free(line);
106 if (rp != NULL)
107 break;
108 errno = 0;
109 }
110 if (errno != 0 || ferror(fp)) {
111 if (errno == ENOMEM)
112 getdate_err = 6;
113 else
114 getdate_err = 5;
115 fclose(fp);
116 return (NULL);
117 }
118 if (feof(fp) || (rp != NULL && *rp != '\0')) {
119 getdate_err = 7;
120 return (NULL);
121 }
122 fclose(fp);
123
124 time(&now);
125 tmp = localtime(&now);
126 tmnow = *tmp;
127
128 /*
129 * This implementation does not accept setting the broken-down time
130 * to anything other than the localtime(). It is not possible to
131 * change the scanned timezone with %Z.
132 *
133 * Note IRIX and Solaris accept only the current zone for %Z.
134 * XXX Is there any implementation that matches the standard?
135 * XXX (Or am I reading the standard wrong?)
136 *
137 * Note: Neither XPG 6 (POSIX 2004) nor XPG 7 (POSIX 2008)
138 * requires strptime(3) support for %Z.
139 */
140
141 /*
142 * Given only a weekday find the first matching weekday starting
143 * with the current weekday and moving into the future.
144 */
145 if (rtm.tm_wday != TMSENTINEL && rtm.tm_year == TMSENTINEL &&
146 rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
147 rtm.tm_year = tmnow.tm_year;
148 rtm.tm_mon = tmnow.tm_mon;
149 rtm.tm_mday = tmnow.tm_mday +
150 (rtm.tm_wday - tmnow.tm_wday + 7) % 7;
151 }
152
153 /*
154 * Given only a month (and no year) find the first matching month
155 * starting with the current month and moving into the future.
156 */
157 if (rtm.tm_mon != TMSENTINEL) {
158 if (rtm.tm_year == TMSENTINEL) {
159 rtm.tm_year = tmnow.tm_year +
160 ((rtm.tm_mon < tmnow.tm_mon)? 1 : 0);
161 }
162 if (rtm.tm_mday == TMSENTINEL) {
163 /* assume the first of the month */
164 rtm.tm_mday = 1;
165 /*
166 * XXX This isn't documented! Just observed behavior.
167 *
168 * Given the weekday find the first matching weekday
169 * starting with the weekday of the first day of the
170 * the month and moving into the future.
171 */
172 if (rtm.tm_wday != TMSENTINEL) {
173 struct tm tm;
174
175 memset(&tm, 0, sizeof(struct tm));
176 tm.tm_year = rtm.tm_year;
177 tm.tm_mon = rtm.tm_mon;
178 tm.tm_mday = 1;
179 mktime(&tm);
180 rtm.tm_mday +=
181 (rtm.tm_wday - tm.tm_wday + 7) % 7;
182 }
183 }
184 }
185
186 /*
187 * Given no time of day assume the current time of day.
188 */
189 if (rtm.tm_hour == TMSENTINEL &&
190 rtm.tm_min == TMSENTINEL && rtm.tm_sec == TMSENTINEL) {
191 rtm.tm_hour = tmnow.tm_hour;
192 rtm.tm_min = tmnow.tm_min;
193 rtm.tm_sec = tmnow.tm_sec;
194 }
195 /*
196 * Given an hour and no date, find the first matching hour starting
197 * with the current hour and moving into the future
198 */
199 if (rtm.tm_hour != TMSENTINEL &&
200 rtm.tm_year == TMSENTINEL && rtm.tm_mon == TMSENTINEL &&
201 rtm.tm_mday == TMSENTINEL) {
202 rtm.tm_year = tmnow.tm_year;
203 rtm.tm_mon = tmnow.tm_mon;
204 rtm.tm_mday = tmnow.tm_mday;
205 if (rtm.tm_hour < tmnow.tm_hour)
206 rtm.tm_hour += 24;
207 }
208
209 /*
210 * Set to 'sane' values; mktime(3) does funny things otherwise.
211 * No hours, no minutes, no seconds, no service.
212 */
213 if (rtm.tm_hour == TMSENTINEL)
214 rtm.tm_hour = 0;
215 if (rtm.tm_min == TMSENTINEL)
216 rtm.tm_min = 0;
217 if (rtm.tm_sec == TMSENTINEL)
218 rtm.tm_sec = 0;
219
220 /*
221 * Given only a year the values of month, day of month, day of year,
222 * week day and is daylight (summer) time are unspecified.
223 * (Specified on the Solaris man page not POSIX.)
224 */
225 if (rtm.tm_year != TMSENTINEL &&
226 rtm.tm_mon == TMSENTINEL && rtm.tm_mday == TMSENTINEL) {
227 rtm.tm_mon = 0;
228 rtm.tm_mday = 1;
229 /*
230 * XXX More undocumented functionality but observed.
231 *
232 * Given the weekday find the first matching weekday
233 * starting with the weekday of the first day of the
234 * month and moving into the future.
235 */
236 if (rtm.tm_wday != TMSENTINEL) {
237 struct tm tm;
238
239 memset(&tm, 0, sizeof(struct tm));
240 tm.tm_year = rtm.tm_year;
241 tm.tm_mon = rtm.tm_mon;
242 tm.tm_mday = 1;
243 mktime(&tm);
244 rtm.tm_mday += (rtm.tm_wday - tm.tm_wday + 7) % 7;
245 }
246 }
247
248 /*
249 * Given only the century but no year within, the current year
250 * is assumed. (Specified on the Solaris man page not POSIX.)
251 *
252 * Warning ugly end case
253 *
254 * This is more work since strptime(3) doesn't "do the right thing".
255 */
256 if (rtm.tm_year != TMSENTINEL && (rtm.tm_year - 1900) >= 0) {
257 rtm.tm_year -= 1900;
258 rtm.tm_year += (tmnow.tm_year % 100);
259 }
260
261 /*
262 * mktime() will normalize all values and also check that the
263 * value will fit into a time_t.
264 *
265 * This is only for POSIX correctness. A date >= 1900 is
266 * really ok, but using a time_t limits things.
267 */
268 if (mktime(rtmp) < 0) {
269 getdate_err = 8;
270 return (NULL);
271 }
272
273 return (rtmp);
274}