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b604cb9bf6
systemd/src/core/timer.c
Ivan Shapovalov 6e392c9c45 core: do not spawn jobs or touch other units during coldplugging 
Because the order of coldplugging is not defined, we can reference a
not-yet-coldplugged unit and read its state while it has not yet been
set to a meaningful value.

This way, already active units may get started again.

We fix this by deferring such actions until all units have been at
least somehow coldplugged.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=88401
2015-03-07 08:44:57 -05:00

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 "unit.h"
#include "unit-name.h"
#include "timer.h"
#include "dbus-timer.h"
#include "special.h"
#include "bus-util.h"
#include "bus-error.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;
}
void timer_free_values(Timer *t) {
TimerValue *v;
assert(t);
while ((v = t->values)) {
LIST_REMOVE(value, t->values, v);
if (v->calendar_spec)
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)->id, "%s lacks value setting. Refusing.", UNIT(t)->id);
return -EINVAL;
}
return 0;
}
static int timer_add_default_dependencies(Timer *t) {
int r;
TimerValue *v;
assert(t);
r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, NULL, true);
if (r < 0)
return r;
if (UNIT(t)->manager->running_as == SYSTEMD_SYSTEM) {
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 (UNIT(t)->manager->running_as == SYSTEMD_SYSTEM) {
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, NULL);
else {
_cleanup_free_ char *h = NULL;
r = get_home_dir(&h);
if (r < 0)
return log_error_errno(r, "Failed to determine home directory: %m");
t->stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id, NULL);
}
}
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;
if (u->default_dependencies) {
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",
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));
LIST_FOREACH(value, v, t->values) {
if (v->base == TIMER_CALENDAR) {
_cleanup_free_ char *p = NULL;
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);
}
if (state != old_state)
log_unit_debug(UNIT(t)->id,
"%s changed %s -> %s", UNIT(t)->id,
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_enter_waiting_coldplug(Unit *u) {
timer_enter_waiting(TIMER(u), false);
return 0;
}
static int timer_coldplug(Unit *u, Hashmap *deferred_work) {
Timer *t = TIMER(u);
assert(t);
assert(t->state == TIMER_DEAD);
if (t->deserialized_state != t->state) {
if (t->deserialized_state == TIMER_WAITING) {
hashmap_put(deferred_work, u, &timer_enter_waiting_coldplug);
timer_set_state(t, TIMER_WAITING);
} else
timer_set_state(t, t->deserialized_state);
}
return 0;
}
static void timer_enter_dead(Timer *t, TimerResult f) {
assert(t);
if (f != TIMER_SUCCESS)
t->result = f;
timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
}
static usec_t monotonic_to_boottime(usec_t t) {
usec_t a, b;
if (t <= 0)
return 0;
a = now(CLOCK_BOOTTIME);
b = now(CLOCK_MONOTONIC);
if (t + a > b)
return t + a - b;
else
return 0;
}
static void timer_enter_waiting(Timer *t, bool initial) {
bool found_monotonic = false, found_realtime = false;
usec_t ts_realtime, ts_monotonic;
usec_t base = 0;
TimerValue *v;
int r;
/* If we shall wake the system we use the boottime clock
* rather than the monotonic clock. */
ts_realtime = now(CLOCK_REALTIME);
ts_monotonic = now(t->wake_system ? CLOCK_BOOTTIME : CLOCK_MONOTONIC);
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:
/* CLOCK_MONOTONIC equals the uptime on Linux */
base = 0;
break;
case TIMER_STARTUP:
base = UNIT(t)->manager->userspace_timestamp.monotonic;
break;
case TIMER_UNIT_ACTIVE:
base = UNIT_TRIGGER(UNIT(t))->inactive_exit_timestamp.monotonic;
if (base <= 0)
base = t->last_trigger.monotonic;
if (base <= 0)
continue;
break;
case TIMER_UNIT_INACTIVE:
base = UNIT_TRIGGER(UNIT(t))->inactive_enter_timestamp.monotonic;
if (base <= 0)
base = t->last_trigger.monotonic;
if (base <= 0)
continue;
break;
default:
assert_not_reached("Unknown timer base");
}
if (t->wake_system)
base = monotonic_to_boottime(base);
v->next_elapse = base + v->value;
if (!initial && v->next_elapse < ts_monotonic && 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)->id, "%s: Timer is elapsed.", UNIT(t)->id);
timer_set_state(t, TIMER_ELAPSED);
return;
}
if (found_monotonic) {
char buf[FORMAT_TIMESPAN_MAX];
log_unit_debug(UNIT(t)->id, "%s: Monotonic timer elapses in %s.",
UNIT(t)->id,
format_timespan(buf, sizeof(buf), t->next_elapse_monotonic_or_boottime > ts_monotonic ? t->next_elapse_monotonic_or_boottime - ts_monotonic : 0, 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);
} 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;
} 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];
log_unit_debug(UNIT(t)->id, "%s: Realtime timer elapses at %s.", UNIT(t)->id, 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);
} 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;
} 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)->id, r, "%s failed to enter waiting state: %m", UNIT(t)->id);
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
}
static void timer_enter_running(Timer *t) {
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
int r;
assert(t);
/* Don't start job if we are supposed to go down */
if (unit_stop_pending(UNIT(t)))
return;
r = manager_add_job(UNIT(t)->manager, JOB_START, UNIT_TRIGGER(UNIT(t)),
JOB_REPLACE, true, &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, 0);
timer_set_state(t, TIMER_RUNNING);
return;
fail:
log_unit_warning(UNIT(t)->id,
"%s failed to queue unit startup job: %s",
UNIT(t)->id, bus_error_message(&error, r));
timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
}
static int timer_start(Unit *u) {
Timer *t = TIMER(u);
TimerValue *v;
assert(t);
assert(t->state == TIMER_DEAD || t->state == TIMER_FAILED);
if (UNIT_TRIGGER(u)->load_state != UNIT_LOADED)
return -ENOENT;
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)
t->last_trigger.realtime = timespec_load(&st.st_atim);
else if (errno == ENOENT)
/* The timer has never run before,
* make sure a stamp file exists.
*/
touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, 0);
}
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->id, "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->id, "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->id, "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->id, "Failed to parse last-trigger-monotonic value %s", value);
} else
log_unit_debug(u->id, "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)->id, "Timer elapsed on %s", UNIT(t)->id);
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)->id, "%s got notified about unit deactivation.", UNIT(t)->id);
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->id, "%s: time change, recalculating next elapse.", u->id);
timer_enter_waiting(t, false);
}
static const char* const timer_state_table[_TIMER_STATE_MAX] = {
[TIMER_DEAD] = "dead",
[TIMER_WAITING] = "waiting",
[TIMER_RUNNING] = "running",
[TIMER_ELAPSED] = "elapsed",
[TIMER_FAILED] = "failed"
};
DEFINE_STRING_TABLE_LOOKUP(timer_state, TimerState);
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"
};
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_interface = "org.freedesktop.systemd1.Timer",
.bus_vtable = bus_timer_vtable,
.bus_set_property = bus_timer_set_property,
.can_transient = true,
};
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