Fix ctime() standard compliance bug

fixes issue2209:
ctime() was updated in 0.9.31 to call localtime_r() instead of
localtime() to
avoid using a static buffer. Unfortunately, this change replaces the
static
buffer (which is zeroed out on initialization) with an uninitialized
local
buffer.

In the common case, this has no effect. However, with a sufficiently
large
time_t value, the value returned differs from that returned by
asctime(localtime(t)), and thus violates the ANSI/ISO standard.

An example input is (on a 64-bit machine):
time_t t = 0x7ffffffffff6c600;

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/libc/misc/time/time.c b/libc/misc/time/time.c
index 758a737fd..ff44892a8 100644
--- a/libc/misc/time/time.c
+++ b/libc/misc/time/time.c
@@ -479,6 +479,7 @@ char *ctime(const time_t *t)
 	 * localtime's static buffer:
 	 */
 	struct tm xtm;
+	memset(&xtm, 0, sizeof(xtm));
 
 	return asctime(localtime_r(t, &xtm));
 }