systemd/0594-core-Detect-initial-timer-state-from-serialized-data.patch

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From 3d4280d0a487109f8f648147083baf573e4418a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>
Date: Fri, 2 Nov 2018 20:56:08 +0100
Subject: [PATCH] core: Detect initial timer state from serialized data
We keep a mark whether a single-shot timer was triggered in the caller's
variable initial. When such a timer elapses while we are
serializing/deserializing the inner state, we consider the timer
incorrectly as elapsed and don't trigger it later.
This patch exploits last_trigger timestamp that we already serialize,
hence we can eliminate the argument initial completely.
A reproducer for OnBootSec= timers:
cat >repro.c <<EOD
/*
* Compile: gcc repro.c -o repro
* Run: ./repro
*/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
int main(int argc, char *argv[]) {
char command[1024];
int pause;
struct timespec now;
while (1) {
usleep(rand() % 200000); // prevent periodic repeats
clock_gettime(CLOCK_MONOTONIC, &now);
printf("%i\n", now.tv_sec);
system("rm -f $PWD/mark");
snprintf(command, 1024, "systemd-run --user --on-boot=%i --timer-property=AccuracySec=100ms "
"touch $PWD/mark", now.tv_sec + 1);
system(command);
system("systemctl --user list-timers");
pause = (1000000000 - now.tv_nsec)/1000 - 70000; // fiddle to hit the middle of reloading
usleep(pause > 0 ? pause : 0);
system("systemctl --user daemon-reload");
sync();
sleep(2);
if (open("./mark", 0) < 0)
if (errno == ENOENT) {
printf("mark file does not exist\n");
break;
}
}
return 0;
}
EOD
(cherry picked from commit aa1f95d2647197eca84c33a0f10adaeada08467d)
Resolves: #1899402
---
src/core/timer.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/src/core/timer.c b/src/core/timer.c
index ef240a6f19..1718ffc5a5 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -262,7 +262,7 @@ static void timer_set_state(Timer *t, TimerState state) {
unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
}
-static void timer_enter_waiting(Timer *t, bool initial, bool time_change);
+static void timer_enter_waiting(Timer *t, bool time_change);
static int timer_coldplug(Unit *u) {
Timer *t = TIMER(u);
@@ -274,7 +274,7 @@ static int timer_coldplug(Unit *u) {
return 0;
if (t->deserialized_state == TIMER_WAITING)
- timer_enter_waiting(t, false, false);
+ timer_enter_waiting(t, false);
else
timer_set_state(t, t->deserialized_state);
@@ -334,7 +334,7 @@ static void add_random(Timer *t, usec_t *v) {
log_unit_debug(UNIT(t), "Adding %s random time.", format_timespan(s, sizeof(s), add, 0));
}
-static void timer_enter_waiting(Timer *t, bool initial, bool time_change) {
+static void timer_enter_waiting(Timer *t, bool time_change) {
bool found_monotonic = false, found_realtime = false;
bool leave_around = false;
triple_timestamp ts;
@@ -444,7 +444,8 @@ static void timer_enter_waiting(Timer *t, bool initial, bool time_change) {
v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
- if (!initial && !time_change &&
+ if (dual_timestamp_is_set(&t->last_trigger) &&
+ !time_change &&
v->next_elapse < triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)) &&
IN_SET(v->base, TIMER_ACTIVE, TIMER_BOOT, TIMER_STARTUP)) {
/* This is a one time trigger, disable it now */
@@ -642,7 +643,7 @@ static int timer_start(Unit *u) {
}
t->result = TIMER_SUCCESS;
- timer_enter_waiting(t, true, false);
+ timer_enter_waiting(t, false);
return 1;
}
@@ -764,14 +765,14 @@ static void timer_trigger_notify(Unit *u, Unit *other) {
case TIMER_ELAPSED:
/* Recalculate sleep time */
- timer_enter_waiting(t, false, false);
+ timer_enter_waiting(t, false);
break;
case TIMER_RUNNING:
if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
log_unit_debug(UNIT(t), "Got notified about unit deactivation.");
- timer_enter_waiting(t, false, false);
+ timer_enter_waiting(t, false);
}
break;
@@ -813,7 +814,7 @@ static void timer_time_change(Unit *u) {
t->last_trigger.realtime = ts;
log_unit_debug(u, "Time change, recalculating next elapse.");
- timer_enter_waiting(t, false, true);
+ timer_enter_waiting(t, true);
}
static void timer_timezone_change(Unit *u) {
@@ -825,7 +826,7 @@ static void timer_timezone_change(Unit *u) {
return;
log_unit_debug(u, "Timezone change, recalculating next elapse.");
- timer_enter_waiting(t, false, false);
+ timer_enter_waiting(t, false);
}
static const char* const timer_base_table[_TIMER_BASE_MAX] = {