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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
From: =?utf-8?q?Zbigniew_J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Mon, 22 Mar 2021 12:51:47 +0100
Subject: shared/calendarspec: when mktime() moves us backwards, jump forward
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
When trying to calculate the next firing of 'Sun *-*-* 01:00:00', we'd fall
into an infinite loop, because mktime() moves us "backwards":
Before this patch:
tm_within_bounds: good=0 2021-03-29 01:00:00 → 2021-03-29 00:00:00
tm_within_bounds: good=0 2021-03-29 01:00:00 → 2021-03-29 00:00:00
tm_within_bounds: good=0 2021-03-29 01:00:00 → 2021-03-29 00:00:00
...
We rely on mktime() normalizing the time. The man page does not say that it'll
move the time forward, but our algorithm relies on this. So let's catch this
case explicitly.
With this patch:
$ TZ=Europe/Dublin faketime 2021-03-21 build/systemd-analyze calendar --iterations=5 'Sun *-*-* 01:00:00'
Normalized form: Sun *-*-* 01:00:00
Next elapse: Sun 2021-03-21 01:00:00 GMT
(in UTC): Sun 2021-03-21 01:00:00 UTC
From now: 59min left
Iter. #2: Sun 2021-04-04 01:00:00 IST
(in UTC): Sun 2021-04-04 00:00:00 UTC
From now: 1 weeks 6 days left <---- note the 2 week jump here
Iter. #3: Sun 2021-04-11 01:00:00 IST
(in UTC): Sun 2021-04-11 00:00:00 UTC
From now: 2 weeks 6 days left
Iter. #4: Sun 2021-04-18 01:00:00 IST
(in UTC): Sun 2021-04-18 00:00:00 UTC
From now: 3 weeks 6 days left
Iter. #5: Sun 2021-04-25 01:00:00 IST
(in UTC): Sun 2021-04-25 00:00:00 UTC
From now: 1 months 4 days left
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1941335.
(cherry picked from commit 129cb6e249bef30dc33e08f98f0b27a6de976f6f)
---
src/shared/calendarspec.c | 19 +++++++++++--------
src/test/test-calendarspec.c | 3 +++
test/test-functions | 1 +
3 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/src/shared/calendarspec.c b/src/shared/calendarspec.c
index 80acc57..c8d97c3 100644
--- a/src/shared/calendarspec.c
+++ b/src/shared/calendarspec.c
@@ -1185,15 +1185,18 @@ static int tm_within_bounds(struct tm *tm, bool utc) {
return negative_errno();
/* Did any normalization take place? If so, it was out of bounds before */
- bool good = t.tm_year == tm->tm_year &&
- t.tm_mon == tm->tm_mon &&
- t.tm_mday == tm->tm_mday &&
- t.tm_hour == tm->tm_hour &&
- t.tm_min == tm->tm_min &&
- t.tm_sec == tm->tm_sec;
- if (!good)
+ int cmp = CMP(t.tm_year, tm->tm_year) ?:
+ CMP(t.tm_mon, tm->tm_mon) ?:
+ CMP(t.tm_mday, tm->tm_mday) ?:
+ CMP(t.tm_hour, tm->tm_hour) ?:
+ CMP(t.tm_min, tm->tm_min) ?:
+ CMP(t.tm_sec, tm->tm_sec);
+
+ if (cmp < 0)
+ return -EDEADLK; /* Refuse to go backward */
+ if (cmp > 0)
*tm = t;
- return good;
+ return cmp == 0;
}
static bool matches_weekday(int weekdays_bits, const struct tm *tm, bool utc) {
diff --git a/src/test/test-calendarspec.c b/src/test/test-calendarspec.c
index e0b7f22..1b04186 100644
--- a/src/test/test-calendarspec.c
+++ b/src/test/test-calendarspec.c
@@ -218,6 +218,9 @@ int main(int argc, char* argv[]) {
// Confirm that timezones in the Spec work regardless of current timezone
test_next("2017-09-09 20:42:00 Pacific/Auckland", "", 12345, 1504946520000000);
test_next("2017-09-09 20:42:00 Pacific/Auckland", "EET", 12345, 1504946520000000);
+ /* Check that we don't start looping if mktime() moves us backwards */
+ test_next("Sun *-*-* 01:00:00 Europe/Dublin", "", 1616412478000000, 1617494400000000);
+ test_next("Sun *-*-* 01:00:00 Europe/Dublin", "IST", 1616412478000000, 1617494400000000);
assert_se(calendar_spec_from_string("test", &c) < 0);
assert_se(calendar_spec_from_string(" utc", &c) < 0);
diff --git a/test/test-functions b/test/test-functions
index 52b52bf..beaf4fa 100644
--- a/test/test-functions
+++ b/test/test-functions
@@ -1120,6 +1120,7 @@ install_zoneinfo() {
inst_any /usr/share/zoneinfo/Asia/Vladivostok
inst_any /usr/share/zoneinfo/Australia/Sydney
inst_any /usr/share/zoneinfo/Europe/Berlin
+ inst_any /usr/share/zoneinfo/Europe/Dublin
inst_any /usr/share/zoneinfo/Europe/Kiev
inst_any /usr/share/zoneinfo/Pacific/Auckland
inst_any /usr/share/zoneinfo/Pacific/Honolulu
|
