/contrib/ntp/libntp/prettydate.c

  1/*
  2 * prettydate - convert a time stamp to something readable
  3 */
  4#include <stdio.h>
  5
  6#include "ntp_fp.h"
  7#include "ntp_unixtime.h"	/* includes <sys/time.h> */
  8#include "lib_strbuf.h"
  9#include "ntp_stdlib.h"
 10
 11static const char *months[] = {
 12  "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 13  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 14};
 15
 16static const char *days[] = {
 17  "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 18};
 19
 20/* Helper function to handle possible wraparound of the ntp epoch.
 21
 22   Works by assuming that the localtime/gmtime library functions 
 23   have been updated so that they work
 24*/
 25
 26#define MAX_EPOCH_NR 1000
 27
 28struct tm *
 29ntp2unix_tm(
 30	u_long ntp, int local
 31	)
 32{
 33	time_t t, curr;
 34	struct tm *tm;
 35	int curr_year, epoch_nr;
 36
 37	/* First get the current year: */
 38	curr = time(NULL);
 39	tm = local ? localtime(&curr) : gmtime(&curr);
 40	if (!tm) return NULL;
 41
 42	curr_year = 1900 + tm->tm_year;
 43
 44	/* Convert the ntp timestamp to a unix utc seconds count: */
 45	t = (time_t) ntp - JAN_1970;
 46
 47	/* Check that the ntp timestamp is not before a 136 year window centered
 48	   around the current year:
 49
 50	   Failsafe in case of an infinite loop:
 51       Allow up to 1000 epochs of 136 years each!
 52	*/
 53    for (epoch_nr = 0; epoch_nr < MAX_EPOCH_NR; epoch_nr++) {
 54		tm = local ? localtime(&t) : gmtime(&t);
 55
 56#if SIZEOF_TIME_T < 4
 57# include "Bletch: sizeof(time_t) < 4!"
 58#endif
 59
 60#if SIZEOF_TIME_T == 4
 61		/* If 32 bits, then year is 1970-2038, so no sense looking */
 62		epoch_nr = MAX_EPOCH_NR;
 63#else	/* SIZEOF_TIME_T > 4 */
 64		/* Check that the resulting year is in the correct epoch: */
 65		if (1900 + tm->tm_year > curr_year - 68) break;
 66
 67		/* Epoch wraparound: Add 2^32 seconds! */
 68		t += (time_t) 65536 << 16;
 69#endif /* SIZEOF_TIME_T > 4 */
 70	}
 71	return tm;
 72}
 73
 74char *
 75prettydate(
 76	l_fp *ts
 77	)
 78{
 79	char *bp;
 80	struct tm *tm;
 81	time_t sec;
 82	u_long msec;
 83
 84	LIB_GETBUF(bp);
 85	
 86	sec = ts->l_ui;
 87	msec = ts->l_uf / 4294967;	/* fract / (2 ** 32 / 1000) */
 88
 89	tm = ntp2unix_tm(sec, 1);
 90	if (!tm) {
 91		(void) sprintf(bp, "%08lx.%08lx  --- --- -- ---- --:--:--",
 92		       (u_long)ts->l_ui, (u_long)ts->l_uf);
 93	}
 94	else {
 95		(void) sprintf(bp, "%08lx.%08lx  %s, %s %2d %4d %2d:%02d:%02d.%03lu",
 96		       (u_long)ts->l_ui, (u_long)ts->l_uf, days[tm->tm_wday],
 97		       months[tm->tm_mon], tm->tm_mday, 1900 + tm->tm_year,
 98		       tm->tm_hour,tm->tm_min, tm->tm_sec, msec);
 99	}
100	
101	return bp;
102}
103
104char *
105gmprettydate(
106	l_fp *ts
107	)
108{
109	char *bp;
110	struct tm *tm;
111	time_t sec;
112	u_long msec;
113
114	LIB_GETBUF(bp);
115	
116	sec = ts->l_ui;
117	msec = ts->l_uf / 4294967;	/* fract / (2 ** 32 / 1000) */
118
119	tm = ntp2unix_tm(sec, 0);
120	if (!tm) {
121		(void) sprintf(bp, "%08lx.%08lx  --- --- -- ---- --:--:--",
122		       (u_long)ts->l_ui, (u_long)ts->l_uf);
123	}
124	else {
125		(void) sprintf(bp, "%08lx.%08lx  %s, %s %2d %4d %2d:%02d:%02d.%03lu",
126		       (u_long)ts->l_ui, (u_long)ts->l_uf, days[tm->tm_wday],
127		       months[tm->tm_mon], tm->tm_mday, 1900 + tm->tm_year,
128		       tm->tm_hour,tm->tm_min, tm->tm_sec, msec);
129	}
130
131	return bp;
132}