From: Johannes Maximilian Kuehn <kuehn@ntp.org>
Date: Tue, 25 Nov 2008 21:23:21 +0000 (+0000)
Subject: prettydate.c, caljulian.c, calyearstart.c:
X-Git-Tag: NTP_4_2_5P150~1^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc5e744243f146d66bb6616f74b468efb8e87619;p=thirdparty%2Fntp.git

prettydate.c, caljulian.c, calyearstart.c:
  Added changes from Juergen

bk: 492c6cc9Y5c33PnF5ZqClAC-9NG4wA
---

diff --git a/libntp/caljulian.c b/libntp/caljulian.c
index 68ac6b3f0..7125d0a94 100644
--- a/libntp/caljulian.c
+++ b/libntp/caljulian.c
@@ -9,10 +9,6 @@
 #include "ntp_fp.h"
 #include "ntp_unixtime.h"
 
-#ifdef HAVE_LIMITS_H
-# include <limits.h>
-#endif
-
 #if !(defined(ISC_CHECK_ALL) || defined(ISC_CHECK_NONE) || \
       defined(ISC_CHECK_ENSURE) || defined(ISC_CHECK_INSIST) || \
       defined(ISC_CHECK_INVARIANT))
@@ -58,12 +54,15 @@ caljulian(
 	 * non-negative time stamp afterwards. Though at the time of this
 	 * writing (2008 A.D.) it would be really strange to have systems
 	 * running with clock set to he 1960's or before...
+	 *
+	 * But's important to use a 32 bit max signed value -- LONG_MAX is 64
+	 * bit on a 64-bit system, and it will give wrong results.
 	 */
 	now   = time(NULL);
 	tmplo = (u_int32)now;
 	tmphi = (int32)(now >> 16 >> 16);
 	
-	M_ADD(tmphi, tmplo, 0, LONG_MAX);
+	M_ADD(tmphi, tmplo, 0, ((1UL << 31)-1)); /* 32-bit max signed */
 	M_ADD(tmphi, tmplo, 0, JAN_1970);
 	if ((ntptime > tmplo) && (tmphi > 0))
 		--tmphi;
@@ -73,16 +72,20 @@ caljulian(
 	 * Now split into days and seconds-of-day, using the fact that
 	 * SECSPERDAY (86400) == 675 * 128; we can get roughly 17000 years of
 	 * time scale, using only 32-bit calculations. Some magic numbers here,
-	 * sorry for that.
+	 * sorry for that. (This could be streamlined for 64 bit machines, but
+	 * is worth the trouble?)
 	 */
 	ntptime  = tmplo & 127;	/* save remainder bits */
 	tmplo    = (tmplo >> 7) | (tmphi << 25);
-	ntp_day  =  (u_long)tmplo / 675;
-	ntptime += ((u_long)tmplo % 675) << 7;
+	ntp_day  =  (u_int32)tmplo / 675;
+	ntptime += ((u_int32)tmplo % 675) << 7;
 
-	/* some checks for the algorithm */
+	/* some checks for the algorithm 
+	 * There's some 64-bit trouble out there: the original NTP time stamp
+	 * had only 32 bits, so our calculation invariant only holds in 32 bits!
+	 */
 	NTP_ENSURE(ntptime < SECSPERDAY);
-	NTP_INVARIANT((u_long)(ntptime + ntp_day * SECSPERDAY) == saved_time);
+	NTP_INVARIANT((u_int32)(ntptime + ntp_day * SECSPERDAY) == (u_int32)saved_time);
 
 	/*
 	 * Do the easy stuff first: take care of hh:mm:ss, ignoring leap
diff --git a/libntp/calyearstart.c b/libntp/calyearstart.c
index a6af05402..c5a63f729 100644
--- a/libntp/calyearstart.c
+++ b/libntp/calyearstart.c
@@ -46,8 +46,11 @@ calyearstart(u_long ntp_time)
 	jt.hour     = 0;
 	jt.minute   = 0;
 	jt.second   = 0;
-	NTP_INVARIANT(caltontp(&jt) + delta == ntp_time);
+	NTP_INVARIANT((ntp_u_int32_t)(caltontp(&jt) + delta) == (ntp_u_int32_t)ntp_time);
 #   endif
 
-	return ntp_time - delta;
+	/* The NTP time stamps (l_fp) count seconds unsigned mod 2**32, so we
+	 * have to calculate this in the proper way!
+	 */
+	return (ntp_u_int32_t)(ntp_time - delta);
 }
diff --git a/libntp/prettydate.c b/libntp/prettydate.c
index eba71a901..2899ea52d 100644
--- a/libntp/prettydate.c
+++ b/libntp/prettydate.c
@@ -9,10 +9,6 @@
 #include "ntp_stdlib.h"
 #include "ntp_assert.h"
 
-#ifdef HAVE_LIMITS_H
-# include <limits.h>
-#endif
-
 static const char *months[] = {
   "Jan", "Feb", "Mar", "Apr", "May", "Jun",
   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
@@ -63,8 +59,11 @@ ntp2unix_tm(
 	u_int32    dwlo  = (int32)t; /* might expand for SIZEOF_TIME_T < 4 */
 	int32      dwhi  = (int32)(t >> 16 >> 16);/* double shift: avoid warnings */
 	
-	/* Shift NTP to UN*X epoch, then unfold around currrent time */
-	M_ADD(dwhi, dwlo, 0, LONG_MAX);
+	/* Shift NTP to UN*X epoch, then unfold around currrent time. It's
+	 * important to use a 32 bit max signed value -- LONG_MAX is 64 bit on
+	 * a 64-bit system, and it will give wrong results.
+	 */
+	M_ADD(dwhi, dwlo, 0, ((1UL << 31)-1)); /* 32-bit max signed */
 	if ((ntp -= JAN_1970) > dwlo)
 		--dwhi;
 	dwlo = ntp;