For RFC 850 dates received in HTTP responses, implement the century pivot

described in RFC 2068.  Include a reference to same in the manual page.

2 files changed, 48 insertions, 4 deletions

diff --git a/usr.bin/fetch/fetch.1 b/usr.bin/fetch/fetch.1
index ccbc80c..f3be659 100644
--- a/usr.bin/fetch/fetch.1
+++ b/usr.bin/fetch/fetch.1
@@ -1,7 +1,7 @@
-.\" $Id: fetch.1,v 1.25 1998/11/08 23:18:47 des Exp $
-.Dd July 2, 1996
+.\" $Id: fetch.1,v 1.26 1998/12/08 13:00:48 cracauer Exp $
+.Dd January 15, 1999
 .Dt FETCH 1
-.Os FreeBSD 2.2
+.Os FreeBSD 3.1
 .Sh NAME
 .Nm fetch
 .Nd retrieve a file by Uniform Resource Locator
@@ -316,6 +316,16 @@ connection.
 .Sh SEE ALSO
 .Xr ftp 1 ,
 .Xr tftp 1
+.Rs
+.%A R. Fielding
+.%A J. Gettys
+.%A J. Mogul
+.%A H. Frystyk
+.%A T. Berners-Lee
+.%T "Hypertext Transfer Protocol \-\- HTTP/1.1"
+.%O RFC 2068
+.%D January 1997
+.Re
 .Sh HISTORY
 The 
 .Nm fetch
@@ -371,3 +381,21 @@ and
 .Fl b
 involves a minimum of two round trips (for small replies), one less than
 other implementations.
+.Pp
+The
+.Tn HTTP
+standard requires interpretation of the
+.Tn RFC 850
+date format, which does not provide a century indication.  Versions of
+.Nm fetch
+prior to
+.Fx 3.1
+would interpret all such dates as being in the 1900s.  This version of
+.Nm fetch
+interprets such dates according to the rule given in
+.Tn RFC 2068 :
+.Bd -literal -offset indent
+  o  HTTP/1.1 clients and caches should assume that an RFC-850 date
+     which appears to be more than 50 years in the future is in fact
+     in the past (this helps solve the "year 2000" problem).
+.Ed
diff --git a/usr.bin/fetch/http.c b/usr.bin/fetch/http.c
index ff8d25f..6d3fe26 100644
--- a/usr.bin/fetch/http.c
+++ b/usr.bin/fetch/http.c
@@ -26,7 +26,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: http.c,v 1.21 1998/10/26 02:39:21 fenner Exp $
+ *	$Id: http.c,v 1.22 1998/12/08 13:00:49 cracauer Exp $
  */
 
 #include <sys/types.h>
@@ -1394,6 +1394,14 @@ parse_http_date(char *string)
 		tm.tm_year = i - 1900;
 	} else {
 		/* Monday, 27-Jan-97 14:31:09 stuffwedon'tcareabout */
+		/* Quoth RFC 2068:
+  o  HTTP/1.1 clients and caches should assume that an RFC-850 date
+     which appears to be more than 50 years in the future is in fact
+     in the past (this helps solve the "year 2000" problem).
+                 */
+		time_t now;
+		struct tm *tmnow;
+		int this2dyear;
 		char *comma = strchr(string, ',');
 		char mname[4];
 
@@ -1415,6 +1423,14 @@ parse_http_date(char *string)
 		if (i >= 12)
 			return -1;
 		tm.tm_mon = i;
+		/*
+		 * RFC 2068 year interpretation.
+		 */
+		time(&now);
+		tmnow = gmtime(&now);
+		this2dyear = tmnow->tm_year % 100;
+		if (tm.tm_year - this2dyear >= 50)
+			tm.tm_year += 100;
 	}
 #undef digit