lib/libcrypto/o_time.c

   1 /* $OpenBSD: o_time.c,v 1.15 2014/06/12 15:49:27 deraadt Exp $ */
   2 /* Written by Richard Levitte (richard@levitte.org) for the OpenSSL
   3  * project 2001.
   4  */
   5 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   6  * project 2008.
   7  */
   8 /* ====================================================================
   9  * Copyright (c) 2001 The OpenSSL Project.  All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  *
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  *
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in
  20  *    the documentation and/or other materials provided with the
  21  *    distribution.
  22  *
  23  * 3. All advertising materials mentioning features or use of this
  24  *    software must display the following acknowledgment:
  25  *    "This product includes software developed by the OpenSSL Project
  26  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  27  *
  28  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  29  *    endorse or promote products derived from this software without
  30  *    prior written permission. For written permission, please contact
  31  *    licensing@OpenSSL.org.
  32  *
  33  * 5. Products derived from this software may not be called "OpenSSL"
  34  *    nor may "OpenSSL" appear in their names without prior written
  35  *    permission of the OpenSSL Project.
  36  *
  37  * 6. Redistributions of any form whatsoever must retain the following
  38  *    acknowledgment:
  39  *    "This product includes software developed by the OpenSSL Project
  40  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  43  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  45  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  46  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  47  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  48  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  49  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  51  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  52  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  53  * OF THE POSSIBILITY OF SUCH DAMAGE.
  54  * ====================================================================
  55  *
  56  * This product includes cryptographic software written by Eric Young
  57  * (eay@cryptsoft.com).  This product includes software written by Tim
  58  * Hudson (tjh@cryptsoft.com).
  59  *
  60  */
  61
  62 #include <string.h>
  63
  64 #include "o_time.h"
  65
  66 /* Take a tm structure and add an offset to it. This avoids any OS issues
  67  * with restricted date types and overflows which cause the year 2038
  68  * problem.
  69  */
  70
  71 #define SECS_PER_DAY (24 * 60 * 60)
  72
  73 static long date_to_julian(int y, int m, int d);
  74 static void julian_to_date(long jd, int *y, int *m, int *d);
  75
  76 int
  77 OPENSSL_gmtime_adj(struct tm *tm, int off_day, long offset_sec)
  78 {
  79         int offset_hms, offset_day;
  80         long time_jd;
  81         int time_year, time_month, time_day;
  82         /* split offset into days and day seconds */
  83         offset_day = offset_sec / SECS_PER_DAY;
  84         /* Avoid sign issues with % operator */
  85         offset_hms = offset_sec - (offset_day * SECS_PER_DAY);
  86         offset_day += off_day;
  87         /* Add current time seconds to offset */
  88         offset_hms += tm->tm_hour * 3600 + tm->tm_min * 60 + tm->tm_sec;
  89         /* Adjust day seconds if overflow */
  90         if (offset_hms >= SECS_PER_DAY) {
  91                 offset_day++;
  92                 offset_hms -= SECS_PER_DAY;
  93         } else if (offset_hms < 0) {
  94                 offset_day--;
  95                 offset_hms += SECS_PER_DAY;
  96         }
  97
  98         /* Convert date of time structure into a Julian day number.
  99          */
 100
 101         time_year = tm->tm_year + 1900;
 102         time_month = tm->tm_mon + 1;
 103         time_day = tm->tm_mday;
 104
 105         time_jd = date_to_julian(time_year, time_month, time_day);
 106
 107         /* Work out Julian day of new date */
 108         time_jd += offset_day;
 109
 110         if (time_jd < 0)
 111                 return 0;
 112
 113         /* Convert Julian day back to date */
 114
 115         julian_to_date(time_jd, &time_year, &time_month, &time_day);
 116
 117         if (time_year < 1900 || time_year > 9999)
 118                 return 0;
 119
 120         /* Update tm structure */
 121
 122         tm->tm_year = time_year - 1900;
 123         tm->tm_mon = time_month - 1;
 124         tm->tm_mday = time_day;
 125
 126         tm->tm_hour = offset_hms / 3600;
 127         tm->tm_min = (offset_hms / 60) % 60;
 128         tm->tm_sec = offset_hms % 60;
 129
 130         return 1;
 131
 132 }
 133
 134 /* Convert date to and from julian day
 135  * Uses Fliegel & Van Flandern algorithm
 136  */
 137 static long
 138 date_to_julian(int y, int m, int d)
 139 {
 140         return (1461 * (y + 4800 + (m - 14) / 12)) / 4 +
 141             (367 * (m - 2 - 12 * ((m - 14) / 12))) / 12 -
 142             (3 * ((y + 4900 + (m - 14) / 12) / 100)) / 4 +
 143             d - 32075;
 144 }
 145
 146 static void
 147 julian_to_date(long jd, int *y, int *m, int *d)
 148 {
 149         long  L = jd + 68569;
 150         long  n = (4 * L) / 146097;
 151         long  i, j;
 152
 153         L = L - (146097 * n + 3) / 4;
 154         i = (4000 * (L + 1)) / 1461001;
 155         L = L - (1461 * i) / 4 + 31;
 156         j = (80 * L) / 2447;
 157         *d = L - (2447 * j) / 80;
 158         L = j / 11;
 159         *m = j + 2 - (12 * L);
 160         *y = 100 * (n - 49) + i + L;
 161 }