contrib/sendmail-8.13.4/sendmail/arpadate.c

   1 /*
   2  * Copyright (c) 1998-2001 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
   5  * Copyright (c) 1988, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * By using this file, you agree to the terms and conditions set
   9  * forth in the LICENSE file which can be found at the top level of
  10  * the sendmail distribution.
  11  *
  12  */
  13
  14 #include <sendmail.h>
  15
  16 SM_RCSID("@(#)$Id: arpadate.c,v 8.30 2001/09/11 04:05:12 gshapiro Exp $")
  17
  18 /*
  19 **  ARPADATE -- Create date in ARPANET format
  20 **
  21 **      Parameters:
  22 **              ud -- unix style date string.  if NULL, one is created.
  23 **
  24 **      Returns:
  25 **              pointer to an ARPANET date field
  26 **
  27 **      Side Effects:
  28 **              none
  29 **
  30 **      WARNING:
  31 **              date is stored in a local buffer -- subsequent
  32 **              calls will overwrite.
  33 **
  34 **      Bugs:
  35 **              Timezone is computed from local time, rather than
  36 **              from wherever (and whenever) the message was sent.
  37 **              To do better is very hard.
  38 **
  39 **              Some sites are now inserting the timezone into the
  40 **              local date.  This routine should figure out what
  41 **              the format is and work appropriately.
  42 */
  43
  44 #ifndef TZNAME_MAX
  45 # define TZNAME_MAX     50      /* max size of timezone */
  46 #endif /* ! TZNAME_MAX */
  47
  48 /* values for TZ_TYPE */
  49 #define TZ_NONE         0       /* no character timezone support */
  50 #define TZ_TM_NAME      1       /* use tm->tm_name */
  51 #define TZ_TM_ZONE      2       /* use tm->tm_zone */
  52 #define TZ_TZNAME       3       /* use tzname[] */
  53 #define TZ_TIMEZONE     4       /* use timezone() */
  54
  55 char *
  56 arpadate(ud)
  57         register char *ud;
  58 {
  59         register char *p;
  60         register char *q;
  61         register int off;
  62         register int i;
  63         register struct tm *lt;
  64         time_t t;
  65         struct tm gmt;
  66         char *tz;
  67         static char b[43 + TZNAME_MAX];
  68
  69         /*
  70         **  Get current time.
  71         **      This will be used if a null argument is passed and
  72         **      to resolve the timezone.
  73         */
  74
  75         /* SM_REQUIRE(ud == NULL || strlen(ud) >= 23); */
  76         t = curtime();
  77         if (ud == NULL)
  78                 ud = ctime(&t);
  79
  80         /*
  81         **  Crack the UNIX date line in a singularly unoriginal way.
  82         */
  83
  84         q = b;
  85
  86         p = &ud[0];             /* Mon */
  87         *q++ = *p++;
  88         *q++ = *p++;
  89         *q++ = *p++;
  90         *q++ = ',';
  91         *q++ = ' ';
  92
  93         p = &ud[8];             /* 16 */
  94         if (*p == ' ')
  95                 p++;
  96         else
  97                 *q++ = *p++;
  98         *q++ = *p++;
  99         *q++ = ' ';
 100
 101         p = &ud[4];             /* Sep */
 102         *q++ = *p++;
 103         *q++ = *p++;
 104         *q++ = *p++;
 105         *q++ = ' ';
 106
 107         p = &ud[20];            /* 1979 */
 108         *q++ = *p++;
 109         *q++ = *p++;
 110         *q++ = *p++;
 111         *q++ = *p++;
 112         *q++ = ' ';
 113
 114         p = &ud[11];            /* 01:03:52 */
 115         for (i = 8; i > 0; i--)
 116                 *q++ = *p++;
 117
 118         /*
 119         **  should really get the timezone from the time in "ud" (which
 120         **  is only different if a non-null arg was passed which is different
 121         **  from the current time), but for all practical purposes, returning
 122         **  the current local zone will do (its all that is ever needed).
 123         */
 124
 125         gmt = *gmtime(&t);
 126         lt = localtime(&t);
 127
 128         off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;
 129
 130         /* assume that offset isn't more than a day ... */
 131         if (lt->tm_year < gmt.tm_year)
 132                 off -= 24 * 60;
 133         else if (lt->tm_year > gmt.tm_year)
 134                 off += 24 * 60;
 135         else if (lt->tm_yday < gmt.tm_yday)
 136                 off -= 24 * 60;
 137         else if (lt->tm_yday > gmt.tm_yday)
 138                 off += 24 * 60;
 139
 140         *q++ = ' ';
 141         if (off == 0)
 142         {
 143                 *q++ = 'G';
 144                 *q++ = 'M';
 145                 *q++ = 'T';
 146         }
 147         else
 148         {
 149                 tz = NULL;
 150 #if TZ_TYPE == TZ_TM_NAME
 151                 tz = lt->tm_name;
 152 #endif /* TZ_TYPE == TZ_TM_NAME */
 153 #if TZ_TYPE == TZ_TM_ZONE
 154                 tz = lt->tm_zone;
 155 #endif /* TZ_TYPE == TZ_TM_ZONE */
 156 #if TZ_TYPE == TZ_TZNAME
 157                 {
 158                         extern char *tzname[];
 159
 160                         if (lt->tm_isdst > 0)
 161                                 tz = tzname[1];
 162                         else if (lt->tm_isdst == 0)
 163                                 tz = tzname[0];
 164                         else
 165                                 tz = NULL;
 166                 }
 167 #endif /* TZ_TYPE == TZ_TZNAME */
 168 #if TZ_TYPE == TZ_TIMEZONE
 169                 {
 170                         extern char *timezone();
 171
 172                         tz = timezone(off, lt->tm_isdst);
 173                 }
 174 #endif /* TZ_TYPE == TZ_TIMEZONE */
 175                 if (off < 0)
 176                 {
 177                         off = -off;
 178                         *q++ = '-';
 179                 }
 180                 else
 181                         *q++ = '+';
 182
 183                 if (off >= 24*60)               /* should be impossible */
 184                         off = 23*60+59;         /* if not, insert silly value */
 185
 186                 *q++ = (off / 600) + '0';
 187                 *q++ = (off / 60) % 10 + '0';
 188                 off %= 60;
 189                 *q++ = (off / 10) + '0';
 190                 *q++ = (off % 10) + '0';
 191                 if (tz != NULL && *tz != '\0')
 192                 {
 193                         *q++ = ' ';
 194                         *q++ = '(';
 195                         while (*tz != '\0' && q < &b[sizeof b - 3])
 196                                 *q++ = *tz++;
 197                         *q++ = ')';
 198                 }
 199         }
 200         *q = '\0';
 201
 202         return b;
 203 }