resolv/ns_date.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #if !defined(_LIBC) && !defined(lint)
  19 static const char rcsid[] = "$Id$";
  20 #endif
  21
  22 /* Import. */
  23
  24 #include <arpa/nameser.h>
  25
  26 #include <ctype.h>
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <time.h>
  31
  32 #define SPRINTF(x) ((size_t)sprintf x)
  33
  34 /* Forward. */
  35
  36 static int      datepart(const char *, int, int, int, int *);
  37
  38 /* Public. */
  39
  40 /*%
  41  * Convert a date in ASCII into the number of seconds since
  42  * 1 January 1970 (GMT assumed).  Format is yyyymmddhhmmss, all
  43  * digits required, no spaces allowed.
  44  */
  45
  46 u_int32_t
  47 ns_datetosecs(const char *cp, int *errp) {
  48         struct tm time;
  49         u_int32_t result;
  50         int mdays, i;
  51         static const int days_per_month[12] =
  52                 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  53
  54         if (strlen(cp) != 14U) {
  55                 *errp = 1;
  56                 return (0);
  57         }
  58         *errp = 0;
  59
  60         memset(&time, 0, sizeof time);
  61         time.tm_year  = datepart(cp +  0, 4, 1990, 9999, errp) - 1900;
  62         time.tm_mon   = datepart(cp +  4, 2,   01,   12, errp) - 1;
  63         time.tm_mday  = datepart(cp +  6, 2,   01,   31, errp);
  64         time.tm_hour  = datepart(cp +  8, 2,   00,   23, errp);
  65         time.tm_min   = datepart(cp + 10, 2,   00,   59, errp);
  66         time.tm_sec   = datepart(cp + 12, 2,   00,   59, errp);
  67         if (*errp)              /*%< Any parse errors? */
  68                 return (0);
  69
  70         /*
  71          * OK, now because timegm() is not available in all environments,
  72          * we will do it by hand.  Roll up sleeves, curse the gods, begin!
  73          */
  74
  75 #define SECS_PER_DAY    ((u_int32_t)24*60*60)
  76 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
  77
  78         result  = time.tm_sec;                          /*%< Seconds */
  79         result += time.tm_min * 60;                     /*%< Minutes */
  80         result += time.tm_hour * (60*60);               /*%< Hours */
  81         result += (time.tm_mday - 1) * SECS_PER_DAY;    /*%< Days */
  82         /* Months are trickier.  Look without leaping, then leap */
  83         mdays = 0;
  84         for (i = 0; i < time.tm_mon; i++)
  85                 mdays += days_per_month[i];
  86         result += mdays * SECS_PER_DAY;                 /*%< Months */
  87         if (time.tm_mon > 1 && isleap(1900+time.tm_year))
  88                 result += SECS_PER_DAY;         /*%< Add leapday for this year */
  89         /* First figure years without leapdays, then add them in.  */
  90         /* The loop is slow, FIXME, but simple and accurate.  */
  91         result += (time.tm_year - 70) * (SECS_PER_DAY*365); /*%< Years */
  92         for (i = 70; i < time.tm_year; i++)
  93                 if (isleap(1900+i))
  94                         result += SECS_PER_DAY; /*%< Add leapday for prev year */
  95         return (result);
  96 }
  97
  98 /* Private. */
  99
 100 /*%
 101  * Parse part of a date.  Set error flag if any error.
 102  * Don't reset the flag if there is no error.
 103  */
 104 static int
 105 datepart(const char *buf, int size, int min, int max, int *errp) {
 106         int result = 0;
 107         int i;
 108
 109         for (i = 0; i < size; i++) {
 110                 if (!isdigit((unsigned char)(buf[i])))
 111                         *errp = 1;
 112                 result = (result * 10) + buf[i] - '0';
 113         }
 114         if (result < min)
 115                 *errp = 1;
 116         if (result > max)
 117                 *errp = 1;
 118         return (result);
 119 }
 120
 121 /*! \file */