В Mon, 27 Jan 2014 15:48:50 +0100
Lennart Poettering <lenn...@poettering.net> пишет:
> On Sun, 26.01.14 12:09, Andrey Borzenkov (arvidj...@gmail.com) wrote:
>
> > > > Any advices on how to do that?
> > > > I have both the issue (reproducible on each shutdown) and will to debug.
> > >
> > > Well, enable the debug shell, and then from there try to figure out why
> > > things are stuck. i.e. whether it is systemd --user that really never
> > > exits. Or whether it actually exits but PID 1 doesn't notice it. And
> > > then if you figured out which of the two cases, you'd have to figure out
> > > why that is...
> > >
> > I finally managed to reproduce it with user instance running with debug
> > level (before *any* attempt to add debugging, strace, whatever resulted
> > in problem disappearing).
> >
> > It seems that /bin/kill -RTMIN+24 is being killed itself. I wonder - is
> > it possible that it is the same SIGTERM that is used by PID 1 to stop
> > user@0service?
>
> Ah, bummer! Yikes!
>
> Thanks for tracking this done, this really sounds like you nailed the
> problem. Now, how to fix it?
>
> Hmm, so, I would claim this is a shortcoming of
> KillMode=control-group, which is the default for everything. There has
> been an item on the TODO list to maybe introduce a KillMode=mixed
> setting, which would send SIGTERM only to the main process, and the
> SIGKILL later on to all processes. I am pretty sure that this would
> solve the issue at hand quite nicely here, because the systemd user
> instance would get a nice chance to clean up its own act, before the
> systemd system instance would make tabula rasa...
>
I still favor alternative approach - let systemd wait for main PID
to exit after ExecStop instead. This is functionally equivalent to the
above with slight advantages
- it will probably decrease number of timeouts because systemd will go
on killing spree as soon as main PID exits, not after final timeout.
- it is more generic as it allows any available method to trigger
service stop, not just a signal.
Comments are welcome :)
From: Andrey Borzenkov <arvidj...@gmail.com>
Subject: [PATCH] add WaitForMainPIDOnStop option
WaitForMainPIDOnStop=true will wait for exit of main PID in addition to
command set as ExecStop.
Use it in user@.service to allow user systemd to complete exit transaction
before starting final kill.
---
man/systemd.service.xml | 13 +++++++++++++
src/core/dbus-service.c | 1 +
src/core/load-fragment-gperf.gperf.m4 | 1 +
src/core/service.c | 15 +++++++++++++--
src/core/service.h | 1 +
units/u...@.service.in | 2 ++
6 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index d316ab5..c121c95 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -1016,6 +1016,19 @@ ExecStart=/bin/echo $ONE $TWO ${TWO}
<option>none</option>.</para></listitem>
</varlistentry>
+ <varlistentry>
+
<term><varname>WaitForMainPIDOnStop=</varname></term>
+
+ <listitem><para>Takes a boolean value
+ that specifies whether systemd should
+ additionally wait for the main PID of a service
+ to exit after executing ExecStop command.
+ Default is to wait for completion of ExecStop
+ command only. Defaults to
+ <option>no</option>.</para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
<para>Check
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 3db9339..35a3c2f 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -54,6 +54,7 @@ const sd_bus_vtable bus_service_vtable[] = {
SD_BUS_PROPERTY("RootDirectoryStartOnly", "b", bus_property_get_bool,
offsetof(Service, root_directory_start_only), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("RemainAfterExit", "b", bus_property_get_bool,
offsetof(Service, remain_after_exit), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("GuessMainPID", "b", bus_property_get_bool,
offsetof(Service, guess_main_pid), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("WaitForMainPIDOnStop", "b", bus_property_get_bool,
offsetof(Service, stop_waits_for_main_pid), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("MainPID", "u", bus_property_get_pid,
offsetof(Service, main_pid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("ControlPID", "u", bus_property_get_pid,
offsetof(Service, control_pid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("BusName", "s", NULL, offsetof(Service, bus_name),
SD_BUS_VTABLE_PROPERTY_CONST),
diff --git a/src/core/load-fragment-gperf.gperf.m4
b/src/core/load-fragment-gperf.gperf.m4
index 59b2a64..85aaef7 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -167,6 +167,7 @@ Service.PermissionsStartOnly, config_parse_bool,
0,
Service.RootDirectoryStartOnly, config_parse_bool, 0,
offsetof(Service, root_directory_start_only)
Service.RemainAfterExit, config_parse_bool, 0,
offsetof(Service, remain_after_exit)
Service.GuessMainPID, config_parse_bool, 0,
offsetof(Service, guess_main_pid)
+Service.WaitForMainPIDOnStop, config_parse_bool, 0,
offsetof(Service, stop_waits_for_main_pid)
Service.RestartPreventExitStatus, config_parse_set_status, 0,
offsetof(Service, restart_ignore_status)
Service.SuccessExitStatus, config_parse_set_status, 0,
offsetof(Service, success_status)
m4_ifdef(`HAVE_SYSV_COMPAT',
diff --git a/src/core/service.c b/src/core/service.c
index d949f7a..8e0eb6c 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1269,6 +1269,7 @@ static void service_dump(Unit *u, FILE *f, const char
*prefix) {
"%sRootDirectoryStartOnly: %s\n"
"%sRemainAfterExit: %s\n"
"%sGuessMainPID: %s\n"
+ "%sWaitForMainPIDOnStop: %s\n"
"%sType: %s\n"
"%sRestart: %s\n"
"%sNotifyAccess: %s\n",
@@ -1279,6 +1280,7 @@ static void service_dump(Unit *u, FILE *f, const char
*prefix) {
prefix, yes_no(s->root_directory_start_only),
prefix, yes_no(s->remain_after_exit),
prefix, yes_no(s->guess_main_pid),
+ prefix, yes_no(s->stop_waits_for_main_pid),
prefix, service_type_to_string(s->type),
prefix, service_restart_to_string(s->restart),
prefix, notify_access_to_string(s->notify_access));
@@ -2953,11 +2955,17 @@ static void service_sigchld_event(Unit *u, pid_t pid,
int code, int status) {
case SERVICE_START_POST:
case SERVICE_RELOAD:
- case SERVICE_STOP:
/* Need to wait until the operation is
* done */
break;
+ case SERVICE_STOP:
+ /* If requested, wait for both main and control
+ PID to finish */
+ if (s->stop_waits_for_main_pid &&
!control_pid_good(s))
+ service_enter_signal(s,
SERVICE_STOP_SIGTERM, f);
+ break;
+
case SERVICE_START:
if (s->type == SERVICE_ONESHOT) {
/* This was our main goal, so let's go
on */
@@ -3116,7 +3124,10 @@ static void service_sigchld_event(Unit *u, pid_t pid,
int code, int status) {
break;
case SERVICE_STOP:
- service_enter_signal(s, SERVICE_STOP_SIGTERM,
f);
+ /* If requested, wait for both main and control
+ PID to finish */
+ if (!s->stop_waits_for_main_pid ||
main_pid_good(s) <= 0)
+ service_enter_signal(s,
SERVICE_STOP_SIGTERM, f);
break;
case SERVICE_STOP_SIGTERM:
diff --git a/src/core/service.h b/src/core/service.h
index 1992926..919d54b 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -163,6 +163,7 @@ struct Service {
bool root_directory_start_only;
bool remain_after_exit;
bool guess_main_pid;
+ bool stop_waits_for_main_pid;
/* If we shut down, remember why */
ServiceResult result;
diff --git a/units/u...@.service.in b/units/u...@.service.in
index bfc9b70..ac3caf3 100644
--- a/units/u...@.service.in
+++ b/units/u...@.service.in
@@ -14,4 +14,6 @@ User=%i
PAMName=systemd-user
Type=notify
ExecStart=-@rootlibexecdir@/systemd --user
+ExecStop=@KILL@ -TERM $MANAGERPID
+WaitForMainPIDOnStop=yes
Slice=user-%i.slice
--
tg: (2d5bdf5..) u/wait_for_mainPID_on_stop (depends on: master)
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