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ringlejpoettering
ringlej
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poettering
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Make final kill signal configurable
Usecase is to allow changing the final kill from SIGKILL to SIGQUIT which should create a core dump useful for debugging why the service didn't stop with the SIGTERM
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‎doc/TRANSIENT-SETTINGS.md‎

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Original file line numberDiff line numberDiff line change
@@ -256,6 +256,7 @@ All process killing settings are available for transient units:
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✓ SendSIGHUP=
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✓ KillMode=
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✓ KillSignal=
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✓ FinalKillSignal=
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```
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## Service Unit Settings

‎man/systemd.kill.xml‎

Lines changed: 23 additions & 4 deletions
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@@ -94,7 +94,8 @@
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enabled with <varname>SendSIGHUP=</varname>). If then, after a
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delay (configured via the <varname>TimeoutStopSec=</varname>
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option), processes still remain, the termination request is
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repeated with the <constant>SIGKILL</constant> signal (unless
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repeated with the <constant>SIGKILL</constant> signal or the
98+
signal specified via <varname>FinalKillSignal=</varname> (unless
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this is disabled via the <varname>SendSIGKILL=</varname>
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option). See
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<citerefentry><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>
@@ -135,9 +136,27 @@
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<varlistentry>
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<term><varname>SendSIGKILL=</varname></term>
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<listitem><para>Specifies whether to send
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<constant>SIGKILL</constant> to remaining processes after a
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timeout, if the normal shutdown procedure left processes of
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the service around. Takes a boolean value. Defaults to "yes".
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<constant>SIGKILL</constant> (or the signal specified by
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<varname>FinalKillSignal=</varname>) to remaining processes
141+
after a timeout, if the normal shutdown procedure left
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processes of the service around. Takes a boolean value.
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Defaults to "yes".
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>FinalKillSignal=</varname></term>
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<listitem><para>Specifies which signal to send to remaining
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processes after a timeout if <varname>SendSIGKILL=</varname>
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is enabled. The signal configured here should be one that is
152+
not typically caught and processed by services (<constant>SIGTERM</constant>
153+
is not suitable). Developers can find it useful to use this to
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generate a coredump to troubleshoot why a service did not
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terminate upon receiving the initial <constant>SIGTERM</constant>
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signal. This can be achieved by configuring <varname>LimitCORE=</varname>
157+
and setting <varname>FinalKillSignal=</varname> to either
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<constant>SIGQUIT</constant> or <constant>SIGABRT</constant>
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Defaults to <constant>SIGKILL</constant>.
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</para></listitem>
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</varlistentry>
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‎shell-completion/bash/systemd-run‎

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@@ -79,8 +79,8 @@ _systemd_run() {
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SendSIGKILL= MemoryLimit= CPUShares= BlockIOWeight= User= Group=
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DevicePolicy= KillMode= DeviceAllow= BlockIOReadBandwidth=
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BlockIOWriteBandwidth= BlockIODeviceWeight= Nice= Environment=
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KillSignal= LimitCPU= LimitFSIZE= LimitDATA= LimitSTACK=
83-
LimitCORE= LimitRSS= LimitNOFILE= LimitAS= LimitNPROC=
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KillSignal= FinalKillSignal= LimitCPU= LimitFSIZE= LimitDATA=
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LimitSTACK= LimitCORE= LimitRSS= LimitNOFILE= LimitAS= LimitNPROC=
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LimitMEMLOCK= LimitLOCKS= LimitSIGPENDING= LimitMSGQUEUE=
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LimitNICE= LimitRTPRIO= LimitRTTIME= PrivateTmp= PrivateDevices=
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PrivateNetwork= NoNewPrivileges= WorkingDirectory= RootDirectory=

‎shell-completion/zsh/_systemd-run‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -32,8 +32,8 @@ _arguments \
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SendSIGKILL= MemoryLimit= CPUShares= BlockIOWeight= User= Group= \
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DevicePolicy= KillMode= DeviceAllow= BlockIOReadBandwidth= \
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BlockIOWriteBandwidth= BlockIODeviceWeight= Nice= Environment= \
35-
KillSignal= LimitCPU= LimitFSIZE= LimitDATA= LimitSTACK= \
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LimitCORE= LimitRSS= LimitNOFILE= LimitAS= LimitNPROC= \
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KillSignal= FinalKillSignal= LimitCPU= LimitFSIZE= LimitDATA= \
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LimitSTACK= LimitCORE= LimitRSS= LimitNOFILE= LimitAS= LimitNPROC= \
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LimitMEMLOCK= LimitLOCKS= LimitSIGPENDING= LimitMSGQUEUE= \
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LimitNICE= LimitRTPRIO= LimitRTTIME= PrivateTmp= PrivateDevices= \
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PrivateNetwork= NoNewPrivileges= WorkingDirectory= RootDirectory= \

‎src/core/dbus-kill.c‎

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Original file line numberDiff line numberDiff line change
@@ -12,13 +12,15 @@ const sd_bus_vtable bus_kill_vtable[] = {
1212
SD_BUS_VTABLE_START(0),
1313
SD_BUS_PROPERTY("KillMode", "s", property_get_kill_mode, offsetof(KillContext, kill_mode), SD_BUS_VTABLE_PROPERTY_CONST),
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SD_BUS_PROPERTY("KillSignal", "i", bus_property_get_int, offsetof(KillContext, kill_signal), SD_BUS_VTABLE_PROPERTY_CONST),
15+
SD_BUS_PROPERTY("FinalKillSignal", "i", bus_property_get_int, offsetof(KillContext, final_kill_signal), SD_BUS_VTABLE_PROPERTY_CONST),
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SD_BUS_PROPERTY("SendSIGKILL", "b", bus_property_get_bool, offsetof(KillContext, send_sigkill), SD_BUS_VTABLE_PROPERTY_CONST),
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SD_BUS_PROPERTY("SendSIGHUP", "b", bus_property_get_bool, offsetof(KillContext, send_sighup), SD_BUS_VTABLE_PROPERTY_CONST),
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SD_BUS_VTABLE_END
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};
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static BUS_DEFINE_SET_TRANSIENT_PARSE(kill_mode, KillMode, kill_mode_from_string);
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static BUS_DEFINE_SET_TRANSIENT_TO_STRING(kill_signal, "i", int32_t, int, "%" PRIi32, signal_to_string_with_check);
23+
static BUS_DEFINE_SET_TRANSIENT_TO_STRING(final_kill_signal, "i", int32_t, int, "%" PRIi32, signal_to_string_with_check);
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2325
int bus_kill_context_set_transient_property(
2426
Unit *u,
@@ -47,5 +49,8 @@ int bus_kill_context_set_transient_property(
4749
if (streq(name, "KillSignal"))
4850
return bus_set_transient_kill_signal(u, name, &c->kill_signal, message, flags, error);
4951

52+
if (streq(name, "FinalKillSignal"))
53+
return bus_set_transient_final_kill_signal(u, name, &c->final_kill_signal, message, flags, error);
54+
5055
return 0;
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}

‎src/core/kill.c‎

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Original file line numberDiff line numberDiff line change
@@ -9,6 +9,7 @@ void kill_context_init(KillContext *c) {
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assert(c);
1010

1111
c->kill_signal = SIGTERM;
12+
c->final_kill_signal = SIGKILL;
1213
c->send_sigkill = true;
1314
c->send_sighup = false;
1415
}
@@ -21,10 +22,12 @@ void kill_context_dump(KillContext *c, FILE *f, const char *prefix) {
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fprintf(f,
2223
"%sKillMode: %s\n"
2324
"%sKillSignal: SIG%s\n"
25+
"%sFinalKillSignal: SIG%s\n"
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"%sSendSIGKILL: %s\n"
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"%sSendSIGHUP: %s\n",
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prefix, kill_mode_to_string(c->kill_mode),
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prefix, signal_to_string(c->kill_signal),
30+
prefix, signal_to_string(c->final_kill_signal),
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prefix, yes_no(c->send_sigkill),
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prefix, yes_no(c->send_sighup));
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}

‎src/core/kill.h‎

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@@ -21,6 +21,7 @@ typedef enum KillMode {
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struct KillContext {
2222
KillMode kill_mode;
2323
int kill_signal;
24+
int final_kill_signal;
2425
bool send_sigkill;
2526
bool send_sighup;
2627
};

‎src/core/load-fragment-gperf.gperf.m4‎

Lines changed: 2 additions & 1 deletion
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@@ -151,7 +151,8 @@ m4_define(`KILL_CONTEXT_CONFIG_ITEMS',
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`$1.SendSIGKILL, config_parse_bool, 0, offsetof($1, kill_context.send_sigkill)
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$1.SendSIGHUP, config_parse_bool, 0, offsetof($1, kill_context.send_sighup)
153153
$1.KillMode, config_parse_kill_mode, 0, offsetof($1, kill_context.kill_mode)
154-
$1.KillSignal, config_parse_signal, 0, offsetof($1, kill_context.kill_signal)'
154+
$1.KillSignal, config_parse_signal, 0, offsetof($1, kill_context.kill_signal)
155+
$1.FinalKillSignal, config_parse_signal, 0, offsetof($1, kill_context.final_kill_signal)'
155156
)m4_dnl
156157
m4_define(`CGROUP_CONTEXT_CONFIG_ITEMS',
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`$1.Slice, config_parse_unit_slice, 0, 0

‎src/core/load-fragment.h‎

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@@ -39,6 +39,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_exec_cpu_affinity);
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CONFIG_PARSER_PROTOTYPE(config_parse_exec_secure_bits);
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CONFIG_PARSER_PROTOTYPE(config_parse_capability_set);
4141
CONFIG_PARSER_PROTOTYPE(config_parse_kill_signal);
42+
CONFIG_PARSER_PROTOTYPE(config_parse_final_kill_signal);
4243
CONFIG_PARSER_PROTOTYPE(config_parse_exec_mount_flags);
4344
CONFIG_PARSER_PROTOTYPE(config_parse_timer);
4445
CONFIG_PARSER_PROTOTYPE(config_parse_trigger_unit);

‎src/core/unit.c‎

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Original file line numberDiff line numberDiff line change
@@ -4479,7 +4479,7 @@ static int operation_to_signal(KillContext *c, KillOperation k) {
44794479
return c->kill_signal;
44804480

44814481
case KILL_KILL:
4482-
return SIGKILL;
4482+
return c->final_kill_signal;
44834483

44844484
case KILL_ABORT:
44854485
return SIGABRT;

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