/* $Cambridge: exim/exim-src/src/tod.c,v 1.4 2007/01/08 10:50:18 ph10 Exp $ */

/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) University of Cambridge 1995 - 2007 */
/* See the file NOTICE for conditions of use and distribution. */

/* A function for returning the time of day in various formats */


#include "exim.h"

/* #define TESTING_LOG_DATESTAMP */


static uschar timebuf[sizeof("www, dd-mmm-yyyy hh:mm:ss +zzzz")];


/*************************************************
*                Return timestamp                *
*************************************************/

/* The log timestamp format is dd-mmm-yy so as to be non-confusing on both
sides of the Atlantic. We calculate an explicit numerical offset from GMT for
the full datestamp and BSD inbox datestamp. Note that on some systems
localtime() and gmtime() re-use the same store, so we must save the local time
values before calling gmtime(). If timestamps_utc is set, don't use
localtime(); all times are then in UTC (with offset +0000).

There are also some contortions to get the day of the month without
a leading zero for the full stamp, since Ustrftime() doesn't provide this
option.

Argument:  type of timestamp required:
             tod_bsdin          BSD inbox format
             tod_epoch          Unix epoch format
             tod_full           full date and time
             tod_log            log file data line format,
                                  with zone if log_timezone is TRUE
             tod_log_bare       always without zone
             tod_log_datestamp  for log file names when datestamped
             tod_log_zone       always with zone
             tod_mbx            MBX inbox format
             tod_zone           just the timezone offset
             tod_zulu           time in 8601 zulu format

Returns:   pointer to fixed buffer containing the timestamp
*/

uschar *
tod_stamp(int type)
{
time_t now = time(NULL);
struct tm *t;

/* Vary log type according to timezone requirement */

if (type == tod_log) type = log_timezone? tod_log_zone : tod_log_bare;

/* Styles that don't need local time */

else if (type == tod_epoch)
  {
  (void) sprintf(CS timebuf, "%d", (int)now);  /* Unix epoch format */
  return timebuf;
  }

else if (type == tod_zulu)
  {
  t = gmtime(&now);
  (void) sprintf(CS timebuf, "%04d%02d%02d%02d%02d%02dZ",
    1900 + t->tm_year, 1 + t->tm_mon, t->tm_mday, t->tm_hour, t->tm_min,
    t->tm_sec);
  return timebuf;
  }

/* Convert to local time or UTC */

t = timestamps_utc? gmtime(&now) : localtime(&now);

switch(type)
  {
  case tod_log_bare:          /* Format used in logging without timezone */
  (void) sprintf(CS timebuf, "%04d-%02d-%02d %02d:%02d:%02d",
    1900 + t->tm_year, 1 + t->tm_mon, t->tm_mday,
    t->tm_hour, t->tm_min, t->tm_sec);
  break;

  /* Format used as suffix of log file name when 'log_datestamp' is active. For
  testing purposes, it changes the file every second. */

  case tod_log_datestamp:
  #ifdef TESTING_LOG_DATESTAMP
  (void) sprintf(CS timebuf, "%04d%02d%02d%02d%02d",
    1900 + t->tm_year, 1 + t->tm_mon, t->tm_mday, t->tm_hour, t->tm_min);
  #else
  (void) sprintf(CS timebuf, "%04d%02d%02d",
    1900 + t->tm_year, 1 + t->tm_mon, t->tm_mday);
  #endif
  break;

  /* Format used in BSD inbox separator lines. Sort-of documented in RFC 976
  ("UUCP Mail Interchange Format Standard") but only by example, not by
  explicit definition. The examples show no timezone offsets, and some MUAs
  appear to be sensitive to this, so Exim has been changed to remove the
  timezone offsets that originally appeared. */

  case tod_bsdin:
    {
    int len = Ustrftime(timebuf, sizeof(timebuf), "%a %b %d %H:%M:%S", t);
    Ustrftime(timebuf + len, sizeof(timebuf) - len, " %Y", t);
    }
  break;

  /* Other types require the GMT offset to be calculated, or just set up in the
  case of UTC timestamping. We need to take a copy of the local time first. */

  default:
    {
    int diff_hour, diff_min;
    struct tm local;
    memcpy(&local, t, sizeof(struct tm));

    if (timestamps_utc)
      {
      diff_hour = diff_min = 0;
      }
    else
      {
      struct tm *gmt = gmtime(&now);
      diff_min = 60*(local.tm_hour - gmt->tm_hour) + local.tm_min - gmt->tm_min;
      if (local.tm_year != gmt->tm_year)
        diff_min += (local.tm_year > gmt->tm_year)? 1440 : -1440;
      else if (local.tm_yday != gmt->tm_yday)
        diff_min += (local.tm_yday > gmt->tm_yday)? 1440 : -1440;
      diff_hour = diff_min/60;
      diff_min  = abs(diff_min - diff_hour*60);
      }

    switch(type)
      {
      case tod_log_zone:          /* Format used in logging with timezone */
      (void) sprintf(CS timebuf, "%04d-%02d-%02d %02d:%02d:%02d %+03d%02d",
        1900 + local.tm_year, 1 + local.tm_mon, local.tm_mday,
        local.tm_hour, local.tm_min, local.tm_sec,
        diff_hour, diff_min);
      break;

      case tod_zone:              /* Just the timezone offset */
      (void) sprintf(CS timebuf, "%+03d%02d", diff_hour, diff_min);
      break;

      /* tod_mbx: format used in MBX mailboxes - subtly different to tod_full */

      #ifdef SUPPORT_MBX
      case tod_mbx:
        {
        int len;
        (void) sprintf(CS timebuf, "%02d-", local.tm_mday);
        len = Ustrlen(timebuf);
        len += Ustrftime(timebuf + len, sizeof(timebuf) - len, "%b-%Y %H:%M:%S",
          &local);
        (void) sprintf(CS timebuf + len, " %+03d%02d", diff_hour, diff_min);
        }
      break;
      #endif

      /* tod_full: format used in Received: headers (use as default just in case
      called with a junk type value) */

      default:
        {
        int len = Ustrftime(timebuf, sizeof(timebuf), "%a, ", &local);
        (void) sprintf(CS timebuf + len, "%02d ", local.tm_mday);
        len += Ustrlen(timebuf + len);
        len += Ustrftime(timebuf + len, sizeof(timebuf) - len, "%b %Y %H:%M:%S",
          &local);
        (void) sprintf(CS timebuf + len, " %+03d%02d", diff_hour, diff_min);
        }
      break;
      }
    }
  break;
  }

return timebuf;
}

/* End of tod.c */