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systemd/src/core/timer.c
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Lennart Poettering 4afd3348c7 tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy 
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.

With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.

The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).

This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.

Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:

       #define _cleanup_(function) __attribute__((cleanup(function)))

Or similar, to make the gcc feature easier to use.

Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.

See #2008.
2015-11-27 19:19:36 +01:00

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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 "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 (UNIT(t)->manager->running_as == MANAGER_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 == MANAGER_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_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, 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;
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;
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), "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 (f != 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 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 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_info(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;
usec_t ts_realtime, ts_monotonic;
usec_t base = 0;
bool leave_around = false;
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:
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 = 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:
leave_around = true;
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), "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 = t->next_elapse_monotonic_or_boottime > ts_monotonic ? t->next_elapse_monotonic_or_boottime - ts_monotonic : 0;
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;
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, &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;
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, 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"
};
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,
};
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