1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
From f6651fa449e1d4bbbb466b091f34e6752f6506f9 Mon Sep 17 00:00:00 2001
From: David A Ramos <daramos@gustav.stanford.edu>
Date: Tue, 27 Jul 2010 11:10:15 +0000
Subject: 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>
---
diff --git a/libc/misc/time/time.c b/libc/misc/time/time.c
index dfa8c0d..0d12bf3 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));
}
diff --git a/test/time/tst-ctime.c b/test/time/tst-ctime.c
new file mode 100644
index 0000000..91d827a
--- a/dev/null
+++ b/test/time/tst-ctime.c
@@ -0,0 +1,44 @@
+/* vi: set sw=4 ts=4: */
+/* testcase for ctime(3) with large time
+ * Copyright (C) 2010 David A Ramos <daramos@gustav.stanford.edu>
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define MAX_POSITIVE(type) (~0 & ~((type) 1 << (sizeof(type)*8 - 1)))
+
+int do_test(int argc, char **argv) {
+ char *correct = 0, *s;
+ int status;
+
+ /* need a very high positive number (e.g., max - 1024) */
+ time_t test = MAX_POSITIVE(time_t) - 1024;
+
+ s = asctime(localtime(&test));
+
+ if (s) {
+ // copy static buffer to heap
+ correct = malloc(strlen(s)+1);
+ strcpy(correct, s);
+ }
+
+ s = ctime(&test);
+
+ printf("ANSI:\t%suClibc:\t%s", correct, s);
+
+ if (s != correct && strcmp(correct, s))
+ status = EXIT_FAILURE;
+ else
+ status = EXIT_SUCCESS;
+
+ if (correct)
+ free(correct);
+
+ return status;
+}
+
+#include <test-skeleton.c>
|
