picnoir
/
Systemd
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

containers: systemd exits with non-zero code 

When a systemd service running in a container exits with a non-zero
code, it can be useful to terminate the container immediately and get
the exit code back to the host, when systemd-nspawn returns. This was
not possible to do. This patch adds the following to make it possible:

- Add a read-only "ExitCode" property on PID 1's "Manager" bus object.
  By default, it is 0 so the behaviour stays the same as previously.
- Add a method "SetExitCode" on the same object. The method fails when
  called on baremetal: it is only allowed in containers or in user
  session.
- Add support in systemctl to call "systemctl exit 42". It reuses the
  existing code for user session.
- Add exit.target and systemd-exit.service to the system instance.
- Change main() to actually call systemd-shutdown to exit() with the
  correct value.
- Add verb 'exit' in systemd-shutdown with parameter --exit-code
- Update systemctl manpage.

I used the following to test it:

| $ sudo rkt --debug --insecure-skip-verify run \
|            --mds-register=false --local docker://busybox \
|            --exec=/bin/chroot -- /proc/1/root \
|            systemctl --force exit 42
| ...
| Container rkt-895a0cba-5c66-4fa5-831c-e3f8ddc5810d failed with error code 42.
| $ echo $?
| 42

Fixes https://github.com/systemd/systemd/issues/1290
This commit is contained in:
Alban Crequy 2015-09-18 13:37:34 +02:00
parent a1b7a5bbdd
commit 287419c119
11 changed files with 165 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Makefile.am
View File

@ -474,6 +474,7 @@ dist_systemunit_DATA = \
units/getty.target \
units/halt.target \
units/kexec.target \
units/exit.target \
units/local-fs.target \
units/local-fs-pre.target \
units/initrd.target \
@ -550,6 +551,7 @@ nodist_systemunit_DATA = \
units/systemd-poweroff.service \
units/systemd-reboot.service \
units/systemd-kexec.service \
units/systemd-exit.service \
units/systemd-fsck@.service \
units/systemd-fsck-root.service \
units/systemd-machine-id-commit.service \
@ -601,6 +603,7 @@ EXTRA_DIST += \
units/systemd-poweroff.service.in \
units/systemd-reboot.service.in \
units/systemd-kexec.service.in \
units/systemd-exit.service.in \
units/user/systemd-exit.service.in \
units/systemd-fsck@.service.in \
units/systemd-fsck-root.service.in \

10
man/systemctl.xml
View File

@ -1633,13 +1633,17 @@ kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
</varlistentry>
<varlistentry>
<term><command>exit</command></term>
<term><command>exit <optional><replaceable>EXIT_CODE</replaceable></optional></command></term>
<listitem>
<para>Ask the systemd manager to quit. This is only
supported for user service managers (i.e. in conjunction
with the <option>--user</option> option) and will fail
otherwise.</para>
with the <option>--user</option> option) or in containers
and is equivalent to <command>poweroff</command> otherwise.</para>
<para>The systemd manager can exit with a non-zero exit
code if the optional argument
<replaceable>EXIT_CODE</replaceable> is given.</para>
</listitem>
</varlistentry>

45
man/systemd.special.xml
View File

@ -211,6 +211,26 @@
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>exit.target</filename></term>
<listitem>
<para>A special service unit for shutting down the system or
user service manager. It also works in containers and is
equivalent to <filename>poweroff.target</filename> on
non-container systems.</para>
<para>Applications wanting to terminate the user service
manager should start this unit. If systemd receives
<constant>SIGTERM</constant> or <constant>SIGINT</constant>
when running as user service daemon, it will start this
unit.</para>
<para>Normally, this pulls in
<filename>shutdown.target</filename> which in turn should be
conflicted by all units that want to be shut down on user
service manager exit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>final.target</filename></term>
<listitem>
@ -797,6 +817,7 @@
<para>When systemd runs as a user instance, the following special
units are available, which have similar definitions as their
system counterparts:
<filename>exit.target</filename>,
<filename>default.target</filename>,
<filename>shutdown.target</filename>,
<filename>sockets.target</filename>,
@ -806,30 +827,6 @@
<filename>printer.target</filename>,
<filename>smartcard.target</filename>,
<filename>sound.target</filename>.</para>
<para>In addition, the following special unit is understood only
when systemd runs as service instance:</para>
<variablelist>
<varlistentry>
<term><filename>exit.target</filename></term>
<listitem>
<para>A special service unit for shutting down the user
service manager.</para>
<para>Applications wanting to terminate the user service
manager should start this unit. If systemd receives
<constant>SIGTERM</constant> or <constant>SIGINT</constant>
when running as user service daemon, it will start this
unit.</para>
<para>Normally, this pulls in
<filename>shutdown.target</filename> which in turn should be
conflicted by all units that want to be shut down on user
service manager exit.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>

32
src/core/dbus-manager.c
View File

@ -1201,8 +1201,10 @@ static int method_exit(sd_bus_message *message, void *userdata, sd_bus_error *er
if (r < 0)
return r;
if (m->running_as == MANAGER_SYSTEM)
return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Exit is only supported for user service managers.");
/* Exit() (in contrast to SetExitCode()) is actually allowed even if
* we are running on the host. It will fall back on reboot() in
* systemd-shutdown if it cannot do the exit() because it isn't a
* container. */
m->exit_code = MANAGER_EXIT;
@ -1450,6 +1452,30 @@ static int method_unset_and_set_environment(sd_bus_message *message, void *userd
return sd_bus_reply_method_return(message, NULL);
}
static int method_set_exit_code(sd_bus_message *message, void *userdata, sd_bus_error *error) {
uint8_t code;
Manager *m = userdata;
int r;
assert(message);
assert(m);
r = mac_selinux_access_check(message, "exit", error);
if (r < 0)
return r;
r = sd_bus_message_read_basic(message, 'y', &code);
if (r < 0)
return r;
if (m->running_as == MANAGER_SYSTEM && detect_container() <= 0)
return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "ExitCode can only be set for user service managers or in containers.");
m->return_value = code;
return sd_bus_reply_method_return(message, NULL);
}
static int method_list_unit_files(sd_bus_message *message, void *userdata, sd_bus_error *error) {
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
Manager *m = userdata;
@ -1933,6 +1959,7 @@ const sd_bus_vtable bus_manager_vtable[] = {
SD_BUS_WRITABLE_PROPERTY("ShutdownWatchdogUSec", "t", bus_property_get_usec, bus_property_set_usec, offsetof(Manager, shutdown_watchdog), 0),
SD_BUS_PROPERTY("ControlGroup", "s", NULL, offsetof(Manager, cgroup_root), 0),
SD_BUS_PROPERTY("SystemState", "s", property_get_system_state, 0, 0),
SD_BUS_PROPERTY("ExitCode", "y", bus_property_get_unsigned, offsetof(Manager, return_value), 0),
SD_BUS_METHOD("GetUnit", "s", "o", method_get_unit, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("GetUnitByPID", "u", "o", method_get_unit_by_pid, SD_BUS_VTABLE_UNPRIVILEGED),
@ -1986,6 +2013,7 @@ const sd_bus_vtable bus_manager_vtable[] = {
SD_BUS_METHOD("GetDefaultTarget", NULL, "s", method_get_default_target, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("PresetAllUnitFiles", "sbb", "a(sss)", method_preset_all_unit_files, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("AddDependencyUnitFiles", "asssbb", "a(sss)", method_add_dependency_unit_files, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("SetExitCode", "y", NULL, method_set_exit_code, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_SIGNAL("UnitNew", "so", 0),
SD_BUS_SIGNAL("UnitRemoved", "so", 0),

21
src/core/main.c
View File

@ -1254,6 +1254,7 @@ int main(int argc, char *argv[]) {
char *switch_root_dir = NULL, *switch_root_init = NULL;
struct rlimit saved_rlimit_nofile = RLIMIT_MAKE_CONST(0);
const char *error_message = NULL;
uint8_t shutdown_exit_code = 0;
#ifdef HAVE_SYSV_COMPAT
if (getpid() != 1 && strstr(program_invocation_short_name, "init")) {
@ -1764,11 +1765,6 @@ int main(int argc, char *argv[]) {
switch (m->exit_code) {
case MANAGER_EXIT:
retval = EXIT_SUCCESS;
log_debug("Exit.");
goto finish;
case MANAGER_RELOAD:
log_info("Reloading.");
@ -1810,11 +1806,13 @@ int main(int argc, char *argv[]) {
log_notice("Switching root.");
goto finish;
case MANAGER_EXIT:
case MANAGER_REBOOT:
case MANAGER_POWEROFF:
case MANAGER_HALT:
case MANAGER_KEXEC: {
static const char * const table[_MANAGER_EXIT_CODE_MAX] = {
[MANAGER_EXIT] = "exit",
[MANAGER_REBOOT] = "reboot",
[MANAGER_POWEROFF] = "poweroff",
[MANAGER_HALT] = "halt",
@ -1836,8 +1834,10 @@ int main(int argc, char *argv[]) {
finish:
pager_close();
if (m)
if (m) {
arg_shutdown_watchdog = m->shutdown_watchdog;
shutdown_exit_code = m->return_value;
}
m = manager_free(m);
for (j = 0; j < ELEMENTSOF(arg_default_rlimit); j++)
@ -1978,7 +1978,8 @@ finish:
if (shutdown_verb) {
char log_level[DECIMAL_STR_MAX(int) + 1];
const char* command_line[9] = {
char exit_code[DECIMAL_STR_MAX(uint8_t) + 1];
const char* command_line[11] = {
SYSTEMD_SHUTDOWN_BINARY_PATH,
shutdown_verb,
"--log-level", log_level,
@ -2015,6 +2016,12 @@ finish:
if (log_get_show_location())
command_line[pos++] = "--log-location";
if (streq(shutdown_verb, "exit")) {
command_line[pos++] = "--exit-code";
command_line[pos++] = exit_code;
xsprintf(exit_code, "%d", shutdown_exit_code);
}
assert(pos < ELEMENTSOF(command_line));
if (arm_reboot_watchdog && arg_shutdown_watchdog > 0) {

5
src/core/manager.h
View File

@ -242,6 +242,11 @@ struct Manager {
bool test_run:1;
/* If non-zero, exit with the following value when the systemd
* process terminate. Useful for containers: systemd-nspawn could get
* the return value. */
uint8_t return_value;
ShowStatus show_status;
bool confirm_spawn;
bool no_console_output;

22
src/core/shutdown.c
View File

@ -48,6 +48,7 @@
#define FINALIZE_ATTEMPTS 50
static char* arg_verb;
static uint8_t arg_exit_code;
static int parse_argv(int argc, char *argv[]) {
enum {
@ -55,6 +56,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_LOG_TARGET,
ARG_LOG_COLOR,
ARG_LOG_LOCATION,
ARG_EXIT_CODE,
};
static const struct option options[] = {
@ -62,6 +64,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "log-target", required_argument, NULL, ARG_LOG_TARGET },
{ "log-color", optional_argument, NULL, ARG_LOG_COLOR },
{ "log-location", optional_argument, NULL, ARG_LOG_LOCATION },
{ "exit-code", required_argument, NULL, ARG_EXIT_CODE },
{}
};
@ -110,6 +113,13 @@ static int parse_argv(int argc, char *argv[]) {
break;
case ARG_EXIT_CODE:
r = safe_atou8(optarg, &arg_exit_code);
if (r < 0)
log_error("Failed to parse exit code %s, ignoring", optarg);
break;
case '\001':
if (!arg_verb)
arg_verb = optarg;
@ -183,6 +193,8 @@ int main(int argc, char *argv[]) {
cmd = RB_HALT_SYSTEM;
else if (streq(arg_verb, "kexec"))
cmd = LINUX_REBOOT_CMD_KEXEC;
else if (streq(arg_verb, "exit"))
cmd = 0; /* ignored, just checking that arg_verb is valid */
else {
r = -EINVAL;
log_error("Unknown action '%s'.", arg_verb);
@ -339,6 +351,16 @@ int main(int argc, char *argv[]) {
if (!in_container)
sync();
if (streq(arg_verb, "exit")) {
if (in_container)
exit(arg_exit_code);
else {
/* We cannot exit() on the host, fallback on another
* method. */
cmd = RB_POWER_OFF;
}
}
switch (cmd) {
case LINUX_REBOOT_CMD_KEXEC:

30
src/systemctl/systemctl.c
View File

@ -3005,6 +3005,7 @@ static int prepare_firmware_setup(sd_bus *bus) {
}
static int start_special(sd_bus *bus, char **args) {
_cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
enum action a;
int r;
@ -3029,6 +3030,31 @@ static int start_special(sd_bus *bus, char **args) {
r = update_reboot_param_file(args[1]);
if (r < 0)
return r;
} else if (a == ACTION_EXIT && strv_length(args) > 1) {
/* If the exit code is not given on the command line, don't
* reset it to zero: just keep it as it might have been set
* previously. */
uint8_t code = 0;
r = safe_atou8(args[1], &code);
if (r < 0) {
log_error("Invalid exit code.");
return -EINVAL;
}
r = sd_bus_call_method(
bus,
"org.freedesktop.systemd1",
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"SetExitCode",
&error,
NULL,
"y", code);
if (r < 0) {
log_error("Failed to execute operation: %s", bus_error_message(&error, r));
return r;
}
}
if (arg_force >= 2 &&
@ -6224,7 +6250,7 @@ static void systemctl_help(void) {
" poweroff Shut down and power-off the system\n"
" reboot [ARG] Shut down and reboot the system\n"
" kexec Shut down and reboot the system with kexec\n"
" exit Request user instance exit\n"
" exit [EXIT_CODE] Request user instance or container exit\n"
" switch-root ROOT [INIT] Change to a different root file system\n"
" suspend Suspend the system\n"
" hibernate Hibernate the system\n"
@ -7211,7 +7237,7 @@ static int systemctl_main(sd_bus *bus, int argc, char *argv[], int bus_error) {
{ "default", EQUAL, 1, start_special },
{ "rescue", EQUAL, 1, start_special },
{ "emergency", EQUAL, 1, start_special },
{ "exit", EQUAL, 1, start_special },
{ "exit", LESS, 2, start_special },
{ "reset-failed", MORE, 1, reset_failed },
{ "enable", MORE, 2, enable_unit, NOBUS },
{ "disable", MORE, 2, enable_unit, NOBUS },

1
units/.gitignore vendored
View File

@ -30,6 +30,7 @@
/systemd-fsck@.service
/systemd-machine-id-commit.service
/systemd-halt.service
/systemd-exit.service
/systemd-hibernate.service
/systemd-hostnamed.service
/systemd-hybrid-sleep.service

17
units/exit.target Normal file
View File

@ -0,0 +1,17 @@
# This file is part of systemd.
#
# 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.
[Unit]
Description=Exit the container
Documentation=man:systemd.special(7)
DefaultDependencies=no
Requires=systemd-exit.service
After=systemd-exit.service
AllowIsolate=yes
[Install]
Alias=ctrl-alt-del.target

17
units/systemd-exit.service.in Normal file
View File

@ -0,0 +1,17 @@
# This file is part of systemd.
#
# 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.
[Unit]
Description=Exit the Session
Documentation=man:systemd.special(7)
DefaultDependencies=no
Requires=shutdown.target
After=shutdown.target
[Service]
Type=oneshot
ExecStart=@SYSTEMCTL@ --force exit