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core: Record ExecMainStartTimestamp before forking

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Otherwise there's a chance the handover timestamp is less than the
start timestamp depending on the whims of the scheduler.

For non-forking services, we also propagate the start timestamp into
Service->main_exec_status to make sure it starts earlier than the
handoff timestamp.
This commit is contained in:
Daan De Meyer
2024-05-05 14:19:30 +02:00
parent 72007bbc9b
commit 7e0e6b50b4
3 changed files with 22 additions and 14 deletions
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src/core/execute.c
+11 -3
View File
@@ -366,6 +366,7 @@ int exec_spawn(Unit *unit,
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
_cleanup_fdset_free_ FDSet *fdset = NULL;
_cleanup_fclose_ FILE *f = NULL;
dual_timestamp start_timestamp;
int r;
assert(unit);
@@ -446,6 +447,10 @@ int exec_spawn(Unit *unit,
xsprintf(serialization_fd_number, "%i", fileno(f));
/* Record the start timestamp before we fork so that it is guaranteed to be earlier than the
* handoff timestamp. */
dual_timestamp_now(&start_timestamp);
/* The executor binary is pinned, to avoid compatibility problems during upgrades. */
r = posix_spawn_wrapper(
FORMAT_PROC_FD_PATH(unit->manager->executor_fd),
@@ -473,7 +478,7 @@ int exec_spawn(Unit *unit,
log_unit_debug(unit, "Forked %s as " PID_FMT " (%s CLONE_INTO_CGROUP)",
command->path, pidref.pid, r > 0 ? "via" : "without");
exec_status_start(&command->exec_status, pidref.pid);
exec_status_start(&command->exec_status, pidref.pid, &start_timestamp);
*ret = TAKE_PIDREF(pidref);
return 0;
@@ -1816,14 +1821,17 @@ char** exec_context_get_restrict_filesystems(const ExecContext *c) {
return l ? TAKE_PTR(l) : strv_new(NULL);
}
void exec_status_start(ExecStatus *s, pid_t pid) {
void exec_status_start(ExecStatus *s, pid_t pid, const dual_timestamp *ts) {
assert(s);
*s = (ExecStatus) {
.pid = pid,
};
dual_timestamp_now(&s->start_timestamp);
if (ts)
s->start_timestamp = *ts;
else
dual_timestamp_now(&s->start_timestamp);
}
void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status) {
src/core/execute.h
+1 -1
View File
@@ -542,7 +542,7 @@ char** exec_context_get_syscall_log(const ExecContext *c);
char** exec_context_get_address_families(const ExecContext *c);
char** exec_context_get_restrict_filesystems(const ExecContext *c);
void exec_status_start(ExecStatus *s, pid_t pid);
void exec_status_start(ExecStatus *s, pid_t pid, const dual_timestamp *ts);
void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status);
void exec_status_handoff(ExecStatus *s, const struct ucred *ucred, const dual_timestamp *ts);
void exec_status_dump(const ExecStatus *s, FILE *f, const char *prefix);
src/core/service.c
+10 -10
View File
@@ -192,7 +192,7 @@ static void service_unwatch_pid_file(Service *s) {
s->pid_file_pathspec = mfree(s->pid_file_pathspec);
}
static int service_set_main_pidref(Service *s, PidRef pidref_consume) {
static int service_set_main_pidref(Service *s, PidRef pidref_consume, const dual_timestamp *start_timestamp) {
_cleanup_(pidref_done) PidRef pidref = pidref_consume;
int r;
@@ -214,7 +214,7 @@ static int service_set_main_pidref(Service *s, PidRef pidref_consume) {
if (!pidref_equal(&s->main_pid, &pidref)) {
service_unwatch_main_pid(s);
exec_status_start(&s->main_exec_status, pidref.pid);
exec_status_start(&s->main_exec_status, pidref.pid, start_timestamp);
}
s->main_pid = TAKE_PIDREF(pidref);
@@ -1166,7 +1166,7 @@ static int service_load_pid_file(Service *s, bool may_warn) {
} else
log_unit_debug(UNIT(s), "Main PID loaded: "PID_FMT, pidref.pid);
r = service_set_main_pidref(s, TAKE_PIDREF(pidref));
r = service_set_main_pidref(s, TAKE_PIDREF(pidref), /* start_timestamp = */ NULL);
if (r < 0)
return r;
@@ -1196,7 +1196,7 @@ static void service_search_main_pid(Service *s) {
return;
log_unit_debug(UNIT(s), "Main PID guessed: "PID_FMT, pid.pid);
if (service_set_main_pidref(s, TAKE_PIDREF(pid)) < 0)
if (service_set_main_pidref(s, TAKE_PIDREF(pid), /* start_timestamp = */ NULL) < 0)
return;
r = unit_watch_pidref(UNIT(s), &s->main_pid, /* exclusive= */ false);
@@ -2417,7 +2417,7 @@ static void service_enter_start(Service *s) {
/* For simple services we immediately start
* the START_POST binaries. */
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref));
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref), &c->exec_status.start_timestamp);
service_enter_start_post(s);
} else if (s->type == SERVICE_FORKING) {
@@ -2436,7 +2436,7 @@ static void service_enter_start(Service *s) {
/* For D-Bus services we know the main pid right away, but wait for the bus name to appear on the
* bus. 'notify' and 'exec' services are similar. */
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref));
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref), &c->exec_status.start_timestamp);
service_set_state(s, SERVICE_START);
} else
assert_not_reached();
@@ -2709,7 +2709,7 @@ static void service_run_next_main(Service *s) {
return;
}
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref));
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref), &s->main_command->exec_status.start_timestamp);
}
static int service_start(Unit *u) {
@@ -3187,7 +3187,7 @@ static int service_deserialize_item(Unit *u, const char *key, const char *value,
PidRef pidref;
if (!pidref_is_set(&s->main_pid) && deserialize_pidref(fds, value, &pidref) >= 0)
(void) service_set_main_pidref(s, pidref);
(void) service_set_main_pidref(s, pidref, /* start_timestamp = */ NULL);
} else if (streq(key, "main-pid-known")) {
int b;
@@ -4380,7 +4380,7 @@ static void service_notify_message(
log_unit_warning(u, "New main PID "PID_FMT" does not belong to service, refusing.", new_main_pid.pid);
}
if (r > 0) {
(void) service_set_main_pidref(s, TAKE_PIDREF(new_main_pid));
(void) service_set_main_pidref(s, TAKE_PIDREF(new_main_pid), /* start_timestamp = */ NULL);
r = unit_watch_pidref(UNIT(s), &s->main_pid, /* exclusive= */ false);
if (r < 0)
@@ -4676,7 +4676,7 @@ static int bus_name_pid_lookup_callback(sd_bus_message *reply, void *userdata, s
log_unit_debug(UNIT(s), "D-Bus name %s is now owned by process " PID_FMT, s->bus_name, pidref.pid);
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref));
(void) service_set_main_pidref(s, TAKE_PIDREF(pidref), /* start_timestamp = */ NULL);
(void) unit_watch_pidref(UNIT(s), &s->main_pid, /* exclusive= */ false);
return 1;
}