svn commit: r339408 - head/lib/libc/stdtime

[Yuri Pankov]

Author: yuripv
Date: Wed Oct 17 14:51:43 2018
New Revision: 339408
URL: https://svnweb.freebsd.org/changeset/base/339408

Log:
  strptime: fix parsing of tm_year when both %C and %y appear in the
  format string in arbitrary order.  This makes the related test cases in
  lib/libc/tests/time (not yet connected to the build) pass.
  
  While here, don't error on negative tm_year value based on the
  APPLICATION USAGE in
  http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/time.h.html
  (glibc does the same):
  
  tm_year is a signed value; therefore, years before 1900 may be represented.
  
  Approved by:	re (gjb), kib (mentor)
  Differential Revision:	https://reviews.freebsd.org/D17550

Modified:
  head/lib/libc/stdtime/strptime.c

Modified: head/lib/libc/stdtime/strptime.c
==============================================================================
--- head/lib/libc/stdtime/strptime.c	Wed Oct 17 10:31:08 2018	(r339407)
+++ head/lib/libc/stdtime/strptime.c	Wed Oct 17 14:51:43 2018	(r339408)
@@ -95,6 +95,7 @@ _strptime(const char *buf, const char *fmt, struct tm 
 	int	i, len;
 	int flags;
 	int Ealternative, Oalternative;
+	int century, year;
 	const struct lc_time_T *tptr = __get_current_time_locale(locale);
 	static int start_of_month[2][13] = {
 		{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
@@ -102,6 +103,8 @@ _strptime(const char *buf, const char *fmt, struct tm 
 	};
 
 	flags = FLAG_NONE;
+	century = -1;
+	year = -1;
 
 	ptr = fmt;
 	while (*ptr != 0) {
@@ -146,10 +149,8 @@ label:
 				i += *buf - '0';
 				len--;
 			}
-			if (i < 19)
-				return (NULL);
 
-			tm->tm_year = i * 100 - TM_YEAR_BASE;
+			century = i;
 			flags |= FLAG_YEAR;
 
 			break;
@@ -527,13 +528,9 @@ label:
 				len--;
 			}
 			if (c == 'Y')
-				i -= TM_YEAR_BASE;
-			if (c == 'y' && i < 69)
-				i += 100;
-			if (i < 0)
-				return (NULL);
+				century = i / 100;
+			year = i % 100;
 
-			tm->tm_year = i;
 			flags |= FLAG_YEAR;
 
 			break;
@@ -609,6 +606,17 @@ label:
 		default:
 			return (NULL);
 		}
+	}
+
+	if (century != -1 || year != -1) {
+		if (year == -1)
+			year = 0;
+		if (century == -1) {
+			if (year < 69)
+				year += 100;
+		} else
+			year += century * 100 - TM_YEAR_BASE;
+		tm->tm_year = year;
 	}
 
 	if (!(flags & FLAG_YDAY) && (flags & FLAG_YEAR)) {