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 /* Import. */
  19
  20 #include <arpa/nameser.h>
  21
  22 #include <ctype.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <time.h>
  27
  28 #define SPRINTF(x) ((size_t)sprintf x)
  29
  30 /* Forward. */
  31
  32 static int      datepart(const char *, int, int, int, int *);
  33
  34 /* Public. */
  35
  36 /*%
  37  * Convert a date in ASCII into the number of seconds since
  38  * 1 January 1970 (GMT assumed).  Format is yyyymmddhhmmss, all
  39  * digits required, no spaces allowed.
  40  */
  41
  42 uint32_t
  43 ns_datetosecs(const char *cp, int *errp) {
  44         struct tm time;
  45         uint32_t result;
  46         int mdays, i;
  47         static const int days_per_month[12] =
  48                 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  49
  50         if (strlen(cp) != 14U) {
  51                 *errp = 1;
  52                 return (0);
  53         }
  54         *errp = 0;
  55
  56         memset(&time, 0, sizeof time);
  57         time.tm_year  = datepart(cp +  0, 4, 1990, 9999, errp) - 1900;
  58         time.tm_mon   = datepart(cp +  4, 2,   01,   12, errp) - 1;
  59         time.tm_mday  = datepart(cp +  6, 2,   01,   31, errp);
  60         time.tm_hour  = datepart(cp +  8, 2,   00,   23, errp);
  61         time.tm_min   = datepart(cp + 10, 2,   00,   59, errp);
  62         time.tm_sec   = datepart(cp + 12, 2,   00,   59, errp);
  63         if (*errp)              /*%< Any parse errors? */
  64                 return (0);
  65
  66         /*
  67          * OK, now because timegm() is not available in all environments,
  68          * we will do it by hand.  Roll up sleeves, curse the gods, begin!
  69          */
  70
  71 #define SECS_PER_DAY    ((uint32_t)24*60*60)
  72 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
  73
  74         result  = time.tm_sec;                          /*%< Seconds */
  75         result += time.tm_min * 60;                     /*%< Minutes */
  76         result += time.tm_hour * (60*60);               /*%< Hours */
  77         result += (time.tm_mday - 1) * SECS_PER_DAY;    /*%< Days */
  78         /* Months are trickier.  Look without leaping, then leap */
  79         mdays = 0;
  80         for (i = 0; i < time.tm_mon; i++)
  81                 mdays += days_per_month[i];
  82         result += mdays * SECS_PER_DAY;                 /*%< Months */
  83         if (time.tm_mon > 1 && isleap(1900+time.tm_year))
  84                 result += SECS_PER_DAY;         /*%< Add leapday for this year */
  85         /* First figure years without leapdays, then add them in.  */
  86         /* The loop is slow, FIXME, but simple and accurate.  */
  87         result += (time.tm_year - 70) * (SECS_PER_DAY*365); /*%< Years */
  88         for (i = 70; i < time.tm_year; i++)
  89                 if (isleap(1900+i))
  90                         result += SECS_PER_DAY; /*%< Add leapday for prev year */
  91         return (result);
  92 }
  93
  94 /* Private. */
  95
  96 /*%
  97  * Parse part of a date.  Set error flag if any error.
  98  * Don't reset the flag if there is no error.
  99  */
 100 static int
 101 datepart(const char *buf, int size, int min, int max, int *errp) {
 102         int result = 0;
 103         int i;
 104
 105         for (i = 0; i < size; i++) {
 106                 if (!isdigit((unsigned char)(buf[i])))
 107                         *errp = 1;
 108                 result = (result * 10) + buf[i] - '0';
 109         }
 110         if (result < min)
 111                 *errp = 1;
 112         if (result > max)
 113                 *errp = 1;
 114         return (result);
 115 }
 116
 117 /*! \file */