Merge from vendor branch: timezone file structure changes and doco.

Fix localtime.c to deal with new magic number field.

Obtained from: ftp://elsie.nci.nih.gov/pub/tzcode1999a.tar.gz

lib/libc/stdtime/localtime.c

@@ -327,7 +327,7 @@ register struct state * const	sp;
 		if (close(fid) != 0)
 			return -1;
 		p = buf;
-		p += sizeof tzhp->tzh_reserved;
+		p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
 		ttisstdcnt = (int) detzcode(p);
 		p += 4;
 		ttisgmtcnt = (int) detzcode(p);

lib/libc/stdtime/tzfile.5

@@ -1,15 +1,20 @@
+.\"	$Id: tzfile.5,v 1.6 1999/01/20 18:54:12 wollman Exp $
 .Dd September 13, 1994
 .Dt TZFILE 5
-.Os FreeBSD 2.0
+.Os FreeBSD 3.0
 .Sh NAME
 .Nm tzfile
 .Nd timezone information
 .Sh SYNOPSIS
-.Fd #include <tzfile.h>
+.Fd #include "/usr/src/lib/libc/stdtime/tzfile.h"
 .Sh DESCRIPTION
 The time zone information files used by
 .Xr tzset 3
-begin with bytes reserved for future use,
+begin with the magic characters
+.Dq Li TZif
+to identify them as
+time zone information files,
+followed by sixteen bytes reserved for future use,
 followed by four four-byte values
 written in a ``standard'' byte order
 (the high-order byte of the value is written first).
@@ -17,23 +22,25 @@ These values are,
 in order:
 .Pp
 .Bl -tag -compact -width tzh_ttisstdcnt
-.It Li tzh_ttisstdcnt
+.It Va tzh_ttisgmtcnt
+The number of UTC/local indicators stored in the file.
+.It Va tzh_ttisstdcnt
 The number of standard/wall indicators stored in the file.
-.It Li tzh_leapcnt
+.It Va tzh_leapcnt
 The number of leap seconds for which data is stored in the file.
-.It Li tzh_timecnt
+.It Va tzh_timecnt
 The number of ``transition times'' for which data is stored
 in the file.
-.It Li tzh_typecnt
+.It Va tzh_typecnt
 The number of ``local time types'' for which data is stored
 in the file (must not be zero).
-.It Li tzh_charcnt
+.It Va tzh_charcnt
 The number of characters of ``time zone abbreviation strings''
 stored in the file.
 .El
 .Pp
 The above header is followed by
-.Li tzh_timecnt
+.Va tzh_timecnt
 four-byte values of type
 .Fa long ,
 sorted in ascending order.
@@ -42,7 +49,7 @@ Each is used as a transition time (as returned by
 .Xr time 3 )
 at which the rules for computing local time change.
 Next come
-.Li tzh_timecnt
+.Va tzh_timecnt
 one-byte values of type
 .Fa "unsigned char" ;
 each one tells which of the different types of ``local time'' types
@@ -61,30 +68,30 @@ struct ttinfo {
 .Ed
 .Pp
 Each structure is written as a four-byte value for
-.Li tt_gmtoff
+.Va tt_gmtoff
 of type
 .Fa long ,
 in a standard byte order, followed by a one-byte value for
-.Li tt_isdst
+.Va tt_isdst
 and a one-byte value for
-.Li tt_abbrind .
+.Va tt_abbrind .
 In each structure,
-.Li tt_gmtoff
-gives the number of seconds to be added to GMT,
+.Va tt_gmtoff
+gives the number of seconds to be added to UTC,
 .Li tt_isdst
 tells whether
 .Li tm_isdst
 should be set by
 .Xr localtime 3
 and
-.Li tt_abbrind
+.Va tt_abbrind
 serves as an index into the array of time zone abbreviation characters
 that follow the
 .Li ttinfo
 structure(s) in the file.
 .Pp
 Then there are
-.Li tzh_leapcnt
+.Va tzh_leapcnt
 pairs of four-byte values, written in standard byte order;
 the first value of each pair gives the time
 (as returned by
@@ -95,14 +102,22 @@ the second gives the
 number of leap seconds to be applied after the given time.
 The pairs of values are sorted in ascending order by time.
 .Pp
-Finally there are
-.Li tzh_ttisstdcnt
+Then there are
+.Va tzh_ttisstdcnt
 standard/wall indicators, each stored as a one-byte value;
 they tell whether the transition times associated with local time types
 were specified as standard time or wall clock time,
 and are used when a time zone file is used in handling POSIX-style
 time zone environment variables.
 .Pp
+Finally there are
+.Va tzh_ttisgmtcnt
+UTC/local indicators, each stored as a one-byte value;
+they tell whether the transition times associated with local time types
+were specified as UTC or local time,
+and are used when a time zone file is used in handling POSIX-style
+time zone environment variables.
+.Pp
 .Nm localtime
 uses the first standard-time
 .Li ttinfo
@@ -119,3 +134,5 @@ in the file.
 .Xr time2posix 3 ,
 .Xr zic 8
 .\" @(#)tzfile.5	7.2
+.\" This file is in the public domain, so clarified as of
+.\" 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).

lib/libc/stdtime/tzfile.h

@@ -4,7 +4,7 @@
 
 /*
 ** This file is in the public domain, so clarified as of
-** June 5, 1996 by Arthur David Olson (arthur_david_olson@nih.gov).
+** 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
 */
 
 /*
@@ -22,7 +22,7 @@
 #ifndef lint
 #ifndef NOID
 /*
-static char	tzfilehid[] = "@(#)tzfile.h	7.8";
+static char	tzfilehid[] = "@(#)tzfile.h	7.14";
 */
 #endif /* !defined NOID */
 #endif /* !defined lint */
@@ -47,8 +47,11 @@ static char	tzfilehid[] = "@(#)tzfile.h	7.8";
 ** Each file begins with. . .
 */
 
+#define	TZ_MAGIC	"TZif"
+
 struct tzhead {
-	char	tzh_reserved[20];	/* reserved for future use */
+ 	char	tzh_magic[4];		/* TZ_MAGIC */
+	char	tzh_reserved[16];	/* reserved for future use */
 	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
 	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
 	char	tzh_leapcnt[4];		/* coded number of leap seconds */
@@ -63,7 +66,7 @@ struct tzhead {
 **	tzh_timecnt (char [4])s		coded transition times a la time(2)
 **	tzh_timecnt (unsigned char)s	types of local time starting at above
 **	tzh_typecnt repetitions of
-**		one (char [4])		coded GMT offset in seconds
+**		one (char [4])		coded UTC offset in seconds
 **		one (unsigned char)	used to set tm_isdst
 **		one (unsigned char)	that's an abbreviation list index
 **	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
@@ -76,7 +79,7 @@ struct tzhead {
 **					if absent, transition times are
 **					assumed to be wall clock time
 **	tzh_ttisgmtcnt (char)s		indexed by type; if TRUE, transition
-**					time is GMT, if FALSE,
+**					time is UTC, if FALSE,
 **					transition time is local time
 **					if absent, transition times are
 **					assumed to be local time