lib/libc/stdtime/getdate.c

   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
  61 int getdate_err;
  62
  63 struct tm *
  64 getdate(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 }