picnoir/Systemd
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity
Systemd/src/core/timer.c
Lennart Poettering 77542a7905 timer: don't use persietent file timestamps from the future (#6823) 
Also, use the mtime rather than the atime of the timestamp file. While
the atime is not completely wrong, the mtime appears more appropriate
as that's what we actually explicitly change, and is not effected by
mere reading.

Fixes: #6821
2017-09-14 18:26:10 +02:00

862 lines
28 KiB
C
Raw Blame History

/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include "alloc-util.h"
#include "bus-error.h"
#include "bus-util.h"
#include "dbus-timer.h"
#include "fs-util.h"
#include "parse-util.h"
#include "random-util.h"
#include "special.h"
#include "string-table.h"
#include "string-util.h"
#include "timer.h"
#include "unit-name.h"
#include "unit.h"
#include "user-util.h"
#include "virt.h"
static const UnitActiveState state_translation_table[_TIMER_STATE_MAX] = {
[TIMER_DEAD] = UNIT_INACTIVE,
[TIMER_WAITING] = UNIT_ACTIVE,
[TIMER_RUNNING] = UNIT_ACTIVE,
[TIMER_ELAPSED] = UNIT_ACTIVE,
[TIMER_FAILED] = UNIT_FAILED
};
static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata);
static void timer_init(Unit *u) {
Timer *t = TIMER(u);
assert(u);
assert(u->load_state == UNIT_STUB);
t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
t->next_elapse_realtime = USEC_INFINITY;
t->accuracy_usec = u->manager->default_timer_accuracy_usec;
t->remain_after_elapse = true;
}
void timer_free_values(Timer *t) {
TimerValue *v;
assert(t);
while ((v = t->values)) {
LIST_REMOVE(value, t->values, v);
calendar_spec_free(v->calendar_spec);
free(v);
}
}
static void timer_done(Unit *u) {
Timer *t = TIMER(u);
assert(t);
timer_free_values(t);
t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
free(t->stamp_path);
}
static int timer_verify(Timer *t) {
assert(t);
if (UNIT(t)->load_state != UNIT_LOADED)
return 0;
if (!t->values) {
log_unit_error(UNIT(t), "Timer unit lacks value setting. Refusing.");
return -EINVAL;
}
return 0;
}
static int timer_add_default_dependencies(Timer *t) {
int r;
TimerValue *v;
assert(t);
if (!UNIT(t)->default_dependencies)
return 0;
r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, NULL, true);
if (r < 0)
return r;
if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true);
if (r < 0)
return r;
LIST_FOREACH(value, v, t->values) {
if (v->base == TIMER_CALENDAR) {
r = unit_add_dependency_by_name(UNIT(t), UNIT_AFTER, SPECIAL_TIME_SYNC_TARGET, NULL, true);
if (r < 0)
return r;
break;
}
}
}
return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
}
static int timer_setup_persistent(Timer *t) {
int r;
assert(t);
if (!t->persistent)
return 0;
if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
r = unit_require_mounts_for(UNIT(t), "/var/lib/systemd/timers");
if (r < 0)
return r;
t->stamp_path = strappend("/var/lib/systemd/timers/stamp-", UNIT(t)->id);
} else {
const char *e;
e = getenv("XDG_DATA_HOME");
if (e)
t->stamp_path = strjoin(e, "/systemd/timers/stamp-", UNIT(t)->id);
else {
_cleanup_free_ char *h = NULL;
r = get_home_dir(&h);
if (r < 0)
return log_unit_error_errno(UNIT(t), r, "Failed to determine home directory: %m");
t->stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id);
}
}
if (!t->stamp_path)
return log_oom();
return 0;
}
static int timer_load(Unit *u) {
Timer *t = TIMER(u);
int r;
assert(u);
assert(u->load_state == UNIT_STUB);
r = unit_load_fragment_and_dropin(u);
if (r < 0)
return r;
if (u->load_state == UNIT_LOADED) {
if (set_isempty(u->dependencies[UNIT_TRIGGERS])) {
Unit *x;
r = unit_load_related_unit(u, ".service", &x);
if (r < 0)
return r;
r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, x, true);
if (r < 0)
return r;
}
r = timer_setup_persistent(t);
if (r < 0)
return r;
r = timer_add_default_dependencies(t);
if (r < 0)
return r;
}
return timer_verify(t);
}
static void timer_dump(Unit *u, FILE *f, const char *prefix) {
char buf[FORMAT_TIMESPAN_MAX];
Timer *t = TIMER(u);
Unit *trigger;
TimerValue *v;
trigger = UNIT_TRIGGER(u);
fprintf(f,
"%sTimer State: %s\n"
"%sResult: %s\n"
"%sUnit: %s\n"
"%sPersistent: %s\n"
"%sWakeSystem: %s\n"
"%sAccuracy: %s\n"
"%sRemainAfterElapse: %s\n",
prefix, timer_state_to_string(t->state),
prefix, timer_result_to_string(t->result),
prefix, trigger ? trigger->id : "n/a",
prefix, yes_no(t->persistent),
prefix, yes_no(t->wake_system),
prefix, format_timespan(buf, sizeof(buf), t->accuracy_usec, 1),
prefix, yes_no(t->remain_after_elapse));
LIST_FOREACH(value, v, t->values) {
if (v->base == TIMER_CALENDAR) {
_cleanup_free_ char *p = NULL;
(void) calendar_spec_to_string(v->calendar_spec, &p);
fprintf(f,
"%s%s: %s\n",
prefix,
timer_base_to_string(v->base),
strna(p));
} else {
char timespan1[FORMAT_TIMESPAN_MAX];
fprintf(f,
"%s%s: %s\n",
prefix,
timer_base_to_string(v->base),
format_timespan(timespan1, sizeof(timespan1), v->value, 0));
}
}
}
static void timer_set_state(Timer *t, TimerState state) {
TimerState old_state;
assert(t);
old_state = t->state;
t->state = state;
if (state != TIMER_WAITING) {
t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
t->next_elapse_realtime = USEC_INFINITY;
}
if (state != old_state)
log_unit_debug(UNIT(t), "Changed %s -> %s", timer_state_to_string(old_state), timer_state_to_string(state));
unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], true);
}
static void timer_enter_waiting(Timer *t, bool initial);
static int timer_coldplug(Unit *u) {
Timer *t = TIMER(u);
assert(t);
assert(t->state == TIMER_DEAD);
if (t->deserialized_state == t->state)
return 0;
if (t->deserialized_state == TIMER_WAITING)
timer_enter_waiting(t, false);
else
timer_set_state(t, t->deserialized_state);
return 0;
}
static void timer_enter_dead(Timer *t, TimerResult f) {
assert(t);
if (t->result == TIMER_SUCCESS)
t->result = f;
timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
}
static void timer_enter_elapsed(Timer *t, bool leave_around) {
assert(t);
/* If a unit is marked with RemainAfterElapse=yes we leave it
* around even after it elapsed once, so that starting it
* later again does not necessarily mean immediate
* retriggering. We unconditionally leave units with
* TIMER_UNIT_ACTIVE or TIMER_UNIT_INACTIVE triggers around,
* since they might be restarted automatically at any time
* later on. */
if (t->remain_after_elapse || leave_around)
timer_set_state(t, TIMER_ELAPSED);
else
timer_enter_dead(t, TIMER_SUCCESS);
}
static void add_random(Timer *t, usec_t *v) {
char s[FORMAT_TIMESPAN_MAX];
usec_t add;
assert(t);
assert(v);
if (t->random_usec == 0)
return;
if (*v == USEC_INFINITY)
return;
add = random_u64() % t->random_usec;
if (*v + add < *v) /* overflow */
*v = (usec_t) -2; /* Highest possible value, that is not USEC_INFINITY */
else
*v += add;
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 found_monotonic = false, found_realtime = false;
bool leave_around = false;
triple_timestamp ts;
usec_t base = 0;
TimerValue *v;
Unit *trigger;
int r;
assert(t);
trigger = UNIT_TRIGGER(UNIT(t));
if (!trigger) {
log_unit_error(UNIT(t), "Unit to trigger vanished.");
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
return;
}
triple_timestamp_get(&ts);
t->next_elapse_monotonic_or_boottime = t->next_elapse_realtime = 0;
LIST_FOREACH(value, v, t->values) {
if (v->disabled)
continue;
if (v->base == TIMER_CALENDAR) {
usec_t b;
/* If we know the last time this was
* triggered, schedule the job based relative
* to that. If we don't just start from
* now. */
b = t->last_trigger.realtime > 0 ? t->last_trigger.realtime : ts.realtime;
r = calendar_spec_next_usec(v->calendar_spec, b, &v->next_elapse);
if (r < 0)
continue;
if (!found_realtime)
t->next_elapse_realtime = v->next_elapse;
else
t->next_elapse_realtime = MIN(t->next_elapse_realtime, v->next_elapse);
found_realtime = true;
} else {
switch (v->base) {
case TIMER_ACTIVE:
if (state_translation_table[t->state] == UNIT_ACTIVE)
base = UNIT(t)->inactive_exit_timestamp.monotonic;
else
base = ts.monotonic;
break;
case TIMER_BOOT:
if (detect_container() <= 0) {
/* CLOCK_MONOTONIC equals the uptime on Linux */
base = 0;
break;
}
/* In a container we don't want to include the time the host
* was already up when the container started, so count from
* our own startup. */
/* fall through */
case TIMER_STARTUP:
base = UNIT(t)->manager->userspace_timestamp.monotonic;
break;
case TIMER_UNIT_ACTIVE:
leave_around = true;
base = trigger->inactive_exit_timestamp.monotonic;
if (base <= 0)
base = t->last_trigger.monotonic;
if (base <= 0)
continue;
break;
case TIMER_UNIT_INACTIVE:
leave_around = true;
base = trigger->inactive_enter_timestamp.monotonic;
if (base <= 0)
base = t->last_trigger.monotonic;
if (base <= 0)
continue;
break;
default:
assert_not_reached("Unknown timer base");
}
v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
if (!initial &&
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 */
v->disabled = true;
continue;
}
if (!found_monotonic)
t->next_elapse_monotonic_or_boottime = v->next_elapse;
else
t->next_elapse_monotonic_or_boottime = MIN(t->next_elapse_monotonic_or_boottime, v->next_elapse);
found_monotonic = true;
}
}
if (!found_monotonic && !found_realtime) {
log_unit_debug(UNIT(t), "Timer is elapsed.");
timer_enter_elapsed(t, leave_around);
return;
}
if (found_monotonic) {
char buf[FORMAT_TIMESPAN_MAX];
usec_t left;
add_random(t, &t->next_elapse_monotonic_or_boottime);
left = usec_sub_unsigned(t->next_elapse_monotonic_or_boottime, triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)));
log_unit_debug(UNIT(t), "Monotonic timer elapses in %s.", format_timespan(buf, sizeof(buf), left, 0));
if (t->monotonic_event_source) {
r = sd_event_source_set_time(t->monotonic_event_source, t->next_elapse_monotonic_or_boottime);
if (r < 0)
goto fail;
r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
if (r < 0)
goto fail;
} else {
r = sd_event_add_time(
UNIT(t)->manager->event,
&t->monotonic_event_source,
t->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC,
t->next_elapse_monotonic_or_boottime, t->accuracy_usec,
timer_dispatch, t);
if (r < 0)
goto fail;
(void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
}
} else if (t->monotonic_event_source) {
r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
if (r < 0)
goto fail;
}
if (found_realtime) {
char buf[FORMAT_TIMESTAMP_MAX];
add_random(t, &t->next_elapse_realtime);
log_unit_debug(UNIT(t), "Realtime timer elapses at %s.", format_timestamp(buf, sizeof(buf), t->next_elapse_realtime));
if (t->realtime_event_source) {
r = sd_event_source_set_time(t->realtime_event_source, t->next_elapse_realtime);
if (r < 0)
goto fail;
r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
if (r < 0)
goto fail;
} else {
r = sd_event_add_time(
UNIT(t)->manager->event,
&t->realtime_event_source,
t->wake_system ? CLOCK_REALTIME_ALARM : CLOCK_REALTIME,
t->next_elapse_realtime, t->accuracy_usec,
timer_dispatch, t);
if (r < 0)
goto fail;
(void) sd_event_source_set_description(t->realtime_event_source, "timer-realtime");
}
} else if (t->realtime_event_source) {
r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_OFF);
if (r < 0)
goto fail;
}
timer_set_state(t, TIMER_WAITING);
return;
fail:
log_unit_warning_errno(UNIT(t), r, "Failed to enter waiting state: %m");
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
}
static void timer_enter_running(Timer *t) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
Unit *trigger;
int r;
assert(t);
/* Don't start job if we are supposed to go down */
if (unit_stop_pending(UNIT(t)))
return;
trigger = UNIT_TRIGGER(UNIT(t));
if (!trigger) {
log_unit_error(UNIT(t), "Unit to trigger vanished.");
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
return;
}
r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, &error, NULL);
if (r < 0)
goto fail;
dual_timestamp_get(&t->last_trigger);
if (t->stamp_path)
touch_file(t->stamp_path, true, t->last_trigger.realtime, UID_INVALID, GID_INVALID, MODE_INVALID);
timer_set_state(t, TIMER_RUNNING);
return;
fail:
log_unit_warning(UNIT(t), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
}
static int timer_start(Unit *u) {
Timer *t = TIMER(u);
TimerValue *v;
Unit *trigger;
int r;
assert(t);
assert(t->state == TIMER_DEAD || t->state == TIMER_FAILED);
trigger = UNIT_TRIGGER(u);
if (!trigger || trigger->load_state != UNIT_LOADED) {
log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
return -ENOENT;
}
r = unit_start_limit_test(u);
if (r < 0) {
timer_enter_dead(t, TIMER_FAILURE_START_LIMIT_HIT);
return r;
}
r = unit_acquire_invocation_id(u);
if (r < 0)
return r;
t->last_trigger = DUAL_TIMESTAMP_NULL;
/* Reenable all timers that depend on unit activation time */
LIST_FOREACH(value, v, t->values)
if (v->base == TIMER_ACTIVE)
v->disabled = false;
if (t->stamp_path) {
struct stat st;
if (stat(t->stamp_path, &st) >= 0) {
usec_t ft;
/* Load the file timestamp, but only if it is actually in the past. If it is in the future,
* something is wrong with the system clock. */
ft = timespec_load(&st.st_mtim);
if (ft < now(CLOCK_REALTIME))
t->last_trigger.realtime = ft;
else {
char z[FORMAT_TIMESTAMP_MAX];
log_unit_warning(u, "Not using persistent file timestamp %s as it is in the future.",
format_timestamp(z, sizeof(z), ft));
}
} else if (errno == ENOENT)
/* The timer has never run before,
* make sure a stamp file exists.
*/
(void) touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
}
t->result = TIMER_SUCCESS;
timer_enter_waiting(t, true);
return 1;
}
static int timer_stop(Unit *u) {
Timer *t = TIMER(u);
assert(t);
assert(t->state == TIMER_WAITING || t->state == TIMER_RUNNING || t->state == TIMER_ELAPSED);
timer_enter_dead(t, TIMER_SUCCESS);
return 1;
}
static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
Timer *t = TIMER(u);
assert(u);
assert(f);
assert(fds);
unit_serialize_item(u, f, "state", timer_state_to_string(t->state));
unit_serialize_item(u, f, "result", timer_result_to_string(t->result));
if (t->last_trigger.realtime > 0)
unit_serialize_item_format(u, f, "last-trigger-realtime", "%" PRIu64, t->last_trigger.realtime);
if (t->last_trigger.monotonic > 0)
unit_serialize_item_format(u, f, "last-trigger-monotonic", "%" PRIu64, t->last_trigger.monotonic);
return 0;
}
static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
Timer *t = TIMER(u);
int r;
assert(u);
assert(key);
assert(value);
assert(fds);
if (streq(key, "state")) {
TimerState state;
state = timer_state_from_string(value);
if (state < 0)
log_unit_debug(u, "Failed to parse state value: %s", value);
else
t->deserialized_state = state;
} else if (streq(key, "result")) {
TimerResult f;
f = timer_result_from_string(value);
if (f < 0)
log_unit_debug(u, "Failed to parse result value: %s", value);
else if (f != TIMER_SUCCESS)
t->result = f;
} else if (streq(key, "last-trigger-realtime")) {
r = safe_atou64(value, &t->last_trigger.realtime);
if (r < 0)
log_unit_debug(u, "Failed to parse last-trigger-realtime value: %s", value);
} else if (streq(key, "last-trigger-monotonic")) {
r = safe_atou64(value, &t->last_trigger.monotonic);
if (r < 0)
log_unit_debug(u, "Failed to parse last-trigger-monotonic value: %s", value);
} else
log_unit_debug(u, "Unknown serialization key: %s", key);
return 0;
}
_pure_ static UnitActiveState timer_active_state(Unit *u) {
assert(u);
return state_translation_table[TIMER(u)->state];
}
_pure_ static const char *timer_sub_state_to_string(Unit *u) {
assert(u);
return timer_state_to_string(TIMER(u)->state);
}
static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata) {
Timer *t = TIMER(userdata);
assert(t);
if (t->state != TIMER_WAITING)
return 0;
log_unit_debug(UNIT(t), "Timer elapsed.");
timer_enter_running(t);
return 0;
}
static void timer_trigger_notify(Unit *u, Unit *other) {
Timer *t = TIMER(u);
TimerValue *v;
assert(u);
assert(other);
if (other->load_state != UNIT_LOADED)
return;
/* Reenable all timers that depend on unit state */
LIST_FOREACH(value, v, t->values)
if (v->base == TIMER_UNIT_ACTIVE ||
v->base == TIMER_UNIT_INACTIVE)
v->disabled = false;
switch (t->state) {
case TIMER_WAITING:
case TIMER_ELAPSED:
/* Recalculate sleep time */
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);
}
break;
case TIMER_DEAD:
case TIMER_FAILED:
break;
default:
assert_not_reached("Unknown timer state");
}
}
static void timer_reset_failed(Unit *u) {
Timer *t = TIMER(u);
assert(t);
if (t->state == TIMER_FAILED)
timer_set_state(t, TIMER_DEAD);
t->result = TIMER_SUCCESS;
}
static void timer_time_change(Unit *u) {
Timer *t = TIMER(u);
assert(u);
if (t->state != TIMER_WAITING)
return;
log_unit_debug(u, "Time change, recalculating next elapse.");
timer_enter_waiting(t, false);
}
static const char* const timer_base_table[_TIMER_BASE_MAX] = {
[TIMER_ACTIVE] = "OnActiveSec",
[TIMER_BOOT] = "OnBootSec",
[TIMER_STARTUP] = "OnStartupSec",
[TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
[TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec",
[TIMER_CALENDAR] = "OnCalendar"
};
DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
static const char* const timer_result_table[_TIMER_RESULT_MAX] = {
[TIMER_SUCCESS] = "success",
[TIMER_FAILURE_RESOURCES] = "resources",
[TIMER_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
};
DEFINE_STRING_TABLE_LOOKUP(timer_result, TimerResult);
const UnitVTable timer_vtable = {
.object_size = sizeof(Timer),
.sections =
"Unit\0"
"Timer\0"
"Install\0",
.private_section = "Timer",
.init = timer_init,
.done = timer_done,
.load = timer_load,
.coldplug = timer_coldplug,
.dump = timer_dump,
.start = timer_start,
.stop = timer_stop,
.serialize = timer_serialize,
.deserialize_item = timer_deserialize_item,
.active_state = timer_active_state,
.sub_state_to_string = timer_sub_state_to_string,
.trigger_notify = timer_trigger_notify,
.reset_failed = timer_reset_failed,
.time_change = timer_time_change,
.bus_vtable = bus_timer_vtable,
.bus_set_property = bus_timer_set_property,
.can_transient = true,
};
Reference in a new issue View git blame Copy permalink