core: allow informing systemd about service status changes with RELOADING=1 and STOPPING=1 sd_notify() messages

4 files changed, 185 insertions, 48 deletions

diff --git a/man/sd_notify.xml b/man/sd_notify.xml
index 6bf8230763..fbb882dfd2 100644
--- a/man/sd_notify.xml
+++ b/man/sd_notify.xml
@@ -46,7 +46,7 @@
         <refnamediv>
                 <refname>sd_notify</refname>
                 <refname>sd_notifyf</refname>
-                <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
+                <refpurpose>Notify service manager about start-up completion and other service status changes</refpurpose>
         </refnamediv>
 
         <refsynopsisdiv>
@@ -70,12 +70,12 @@
 
         <refsect1>
                 <title>Description</title>
-                <para><function>sd_notify()</function> shall be called
-                by a daemon to notify the init system about status
-                changes. It can be used to send arbitrary information,
-                encoded in an environment-block-like string. Most
-                importantly it can be used for start-up completion
-                notification.</para>
+                <para><function>sd_notify()</function> may be called
+                by a service to notify the service manager about
+                state changes. It can be used to send arbitrary
+                information, encoded in an environment-block-like
+                string. Most importantly it can be used for start-up
+                completion notification.</para>
 
                 <para>If the <parameter>unset_environment</parameter>
                 parameter is non-zero, <function>sd_notify()</function>
@@ -99,58 +99,87 @@
                         <varlistentry>
                                 <term>READY=1</term>
 
-                                <listitem><para>Tells the init system
-                                that daemon startup is finished. This
-                                is only used by systemd if the service
-                                definition file has Type=notify
-                                set. The passed argument is a boolean
-                                "1" or "0". Since there is little
+                                <listitem><para>Tells the service
+                                manager that service startup is
+                                finished. This is only used by systemd
+                                if the service definition file has
+                                Type=notify set. Since there is little
                                 value in signaling non-readiness, the
-                                only value daemons should send is
-                                "READY=1".</para></listitem>
+                                only value services should send is
+                                <literal>READY=1</literal>
+                                (i.e. <literal>READY=0</literal> is
+                                not defined).</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term>RELOADING=1</term>
+
+                                <listitem><para>Tells the service manager
+                                that the service is reloading its
+                                configuration. This is useful to allow
+                                the service manager to track the service's
+                                internal state, and present it to the
+                                user. Note that a service that sends
+                                this notification must also send a
+                                <literal>READY=1</literal>
+                                notification when it completed
+                                reloading its
+                                configuration.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term>STOPPING=1</term>
+
+                                <listitem><para>Tells the service manager
+                                that the service is beginning its
+                                shutdown. This is useful to allow the
+                                service manager to track the service's
+                                internal state, and present it to the
+                                user.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term>STATUS=...</term>
 
                                 <listitem><para>Passes a single-line
-                                status string back to the init system
-                                that describes the daemon state. This
+                                UTF-8 status string back to the service manager
+                                that describes the service state. This
                                 is free-form and can be used for
                                 various purposes: general state
                                 feedback, fsck-like programs could
                                 pass completion percentages and
                                 failing programs could pass a human
                                 readable error message. Example:
-                                "STATUS=Completed 66% of file system
-                                check..."</para></listitem>
+                                <literal>STATUS=Completed 66% of file
+                                system
+                                check...</literal></para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term>ERRNO=...</term>
 
-                                <listitem><para>If a daemon fails, the
+                                <listitem><para>If a service fails, the
                                 errno-style error code, formatted as
-                                string. Example: "ERRNO=2" for
+                                string. Example: <literal>ERRNO=2</literal> for
                                 ENOENT.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term>BUSERROR=...</term>
 
-                                <listitem><para>If a daemon fails, the
+                                <listitem><para>If a service fails, the
                                 D-Bus error-style error code. Example:
-                                "BUSERROR=org.freedesktop.DBus.Error.TimedOut"</para></listitem>
+                                <literal>BUSERROR=org.freedesktop.DBus.Error.TimedOut</literal></para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term>MAINPID=...</term>
 
                                 <listitem><para>The main pid of the
-                                daemon, in case the init system did
+                                service, in case the service manager did
                                 not fork off the process
                                 itself. Example:
-                                "MAINPID=4711"</para></listitem>
+                                <literal>MAINPID=4711</literal></para></listitem>
                         </varlistentry>
 
                         <varlistentry>
@@ -183,7 +212,7 @@
                 clashes.</para>
 
                 <para>Note that systemd will accept status data sent
-                from a daemon only if the
+                from a service only if the
                 <varname>NotifyAccess=</varname> option is correctly
                 set in the service definition file. See
                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
@@ -222,7 +251,7 @@
                 <varname>$NOTIFY_SOCKET</varname> is <literal>@</literal>, the string is
                 understood as Linux abstract namespace socket. The
                 datagram is accompanied by the process credentials of
-                the sending daemon, using SCM_CREDENTIALS.</para>
+                the sending service, using SCM_CREDENTIALS.</para>
         </refsect1>
 
         <refsect1>
@@ -232,7 +261,7 @@
                         <varlistentry>
                                 <term><varname>$NOTIFY_SOCKET</varname></term>
 
-                                <listitem><para>Set by the init system
+                                <listitem><para>Set by the service manager
                                 for supervised processes for status
                                 and start-up completion
                                 notification. This environment variable
@@ -249,9 +278,9 @@
                 <example>
                         <title>Start-up Notification</title>
 
-                        <para>When a daemon finished starting up, it
+                        <para>When a service finished starting up, it
                         might issue the following call to notify
-                        the init system:</para>
+                        the service manager:</para>
 
                         <programlisting>sd_notify(0, "READY=1");</programlisting>
                 </example>
@@ -259,7 +288,7 @@
                 <example>
                         <title>Extended Start-up Notification</title>
 
-                        <para>A daemon could send the following after
+                        <para>A service could send the following after
                         completing initialization:</para>
 
                         <programlisting>sd_notifyf(0, "READY=1\n"
@@ -271,7 +300,7 @@
                 <example>
                         <title>Error Cause Notification</title>
 
-                        <para>A daemon could send the following shortly before exiting, on failure</para>
+                        <para>A service could send the following shortly before exiting, on failure</para>
 
                         <programlisting>sd_notifyf(0, "STATUS=Failed to start up: %s\n"
               "ERRNO=%i",
diff --git a/src/core/service.c b/src/core/service.c
index 262a40cc8b..3221938793 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -92,6 +92,7 @@ static int service_dispatch_timer(sd_event_source *source, usec_t usec, void *us
 static int service_dispatch_watchdog(sd_event_source *source, usec_t usec, void *userdata);
 
 static void service_enter_signal(Service *s, ServiceState state, ServiceResult f);
+static void service_enter_reload_by_notify(Service *s);
 
 static void service_init(Unit *u) {
         Service *s = SERVICE(u);
@@ -473,7 +474,8 @@ static void service_dump(Unit *u, FILE *f, const char *prefix) {
                 "%sGuessMainPID: %s\n"
                 "%sType: %s\n"
                 "%sRestart: %s\n"
-                "%sNotifyAccess: %s\n",
+                "%sNotifyAccess: %s\n"
+                "%sNotifyState: %s\n",
                 prefix, service_state_to_string(s->state),
                 prefix, service_result_to_string(s->result),
                 prefix, service_result_to_string(s->reload_result),
@@ -483,7 +485,8 @@ static void service_dump(Unit *u, FILE *f, const char *prefix) {
                 prefix, yes_no(s->guess_main_pid),
                 prefix, service_type_to_string(s->type),
                 prefix, service_restart_to_string(s->restart),
-                prefix, notify_access_to_string(s->notify_access));
+                prefix, notify_access_to_string(s->notify_access),
+                prefix, notify_state_to_string(s->notify_state));
 
         if (s->control_pid > 0)
                 fprintf(f,
@@ -1176,6 +1179,17 @@ fail:
                 service_enter_dead(s, SERVICE_FAILURE_RESOURCES, true);
 }
 
+static void service_enter_stop_by_notify(Service *s) {
+        assert(s);
+
+        unit_watch_all_pids(UNIT(s));
+
+        if (s->timeout_stop_usec > 0)
+                service_arm_timer(s, s->timeout_stop_usec);
+
+        service_set_state(s, SERVICE_STOP);
+}
+
 static void service_enter_stop(Service *s, ServiceResult f) {
         int r;
 
@@ -1226,9 +1240,18 @@ static void service_enter_running(Service *s, ServiceResult f) {
         cgroup_ok = cgroup_good(s);
 
         if ((main_pid_ok > 0 || (main_pid_ok < 0 && cgroup_ok != 0)) &&
-            (s->bus_name_good || s->type != SERVICE_DBUS))
-                service_set_state(s, SERVICE_RUNNING);
-        else if (s->remain_after_exit)
+            (s->bus_name_good || s->type != SERVICE_DBUS)) {
+
+                /* If there are any queued up sd_notify()
+                 * notifications, process them now */
+                if (s->notify_state == NOTIFY_RELOADING)
+                        service_enter_reload_by_notify(s);
+                else if (s->notify_state == NOTIFY_STOPPING)
+                        service_enter_stop_by_notify(s);
+                else
+                        service_set_state(s, SERVICE_RUNNING);
+
+        } else if (s->remain_after_exit)
                 service_set_state(s, SERVICE_EXITED);
         else
                 service_enter_stop(s, SERVICE_SUCCESS);
@@ -1433,12 +1456,19 @@ static void service_enter_restart(Service *s) {
         return;
 
 fail:
-        log_warning_unit(UNIT(s)->id,
-                         "%s failed to schedule restart job: %s",
-                         UNIT(s)->id, bus_error_message(&error, -r));
+        log_warning_unit(UNIT(s)->id, "%s failed to schedule restart job: %s", UNIT(s)->id, bus_error_message(&error, -r));
         service_enter_dead(s, SERVICE_FAILURE_RESOURCES, false);
 }
 
+static void service_enter_reload_by_notify(Service *s) {
+        assert(s);
+
+        if (s->timeout_start_usec > 0)
+                service_arm_timer(s, s->timeout_start_usec);
+
+        service_set_state(s, SERVICE_RELOAD);
+}
+
 static void service_enter_reload(Service *s) {
         int r;
 
@@ -1667,6 +1697,8 @@ static int service_start(Unit *u) {
         s->status_text = NULL;
         s->status_errno = 0;
 
+        s->notify_state = NOTIFY_UNKNOWN;
+
         service_enter_start_pre(s);
         return 0;
 }
@@ -2504,13 +2536,15 @@ static int service_dispatch_watchdog(sd_event_source *source, usec_t usec, void
 
 static void service_notify_message(Unit *u, pid_t pid, char **tags) {
         Service *s = SERVICE(u);
-        const char *e;
+        _cleanup_free_ char *cc = NULL;
         bool notify_dbus = false;
+        const char *e;
 
         assert(u);
 
-        log_debug_unit(u->id, "%s: Got notification message from PID "PID_FMT" (%s...)",
-                       u->id, pid, tags && *tags ? tags[0] : "(empty)");
+        cc = strv_join(tags, ", ");
+        log_debug_unit(u->id, "%s: Got notification message from PID "PID_FMT" (%s)",
+                       u->id, pid, isempty(cc) ? "n/a" : cc);
 
         if (s->notify_access == NOTIFY_NONE) {
                 log_warning_unit(u->id, "%s: Got notification message from PID "PID_FMT", but reception is disabled.", u->id, pid);
@@ -2539,10 +2573,46 @@ static void service_notify_message(Unit *u, pid_t pid, char **tags) {
                 }
         }
 
+        /* Interpret RELOADING= */
+        if (strv_find(tags, "RELOADING=1")) {
+
+                log_debug_unit(u->id, "%s: got RELOADING=1", u->id);
+                s->notify_state = NOTIFY_RELOADING;
+
+                if (s->state == SERVICE_RUNNING)
+                        service_enter_reload_by_notify(s);
+
+                notify_dbus = true;
+        }
+
         /* Interpret READY= */
-        if (s->type == SERVICE_NOTIFY && s->state == SERVICE_START && strv_find(tags, "READY=1")) {
+        if (strv_find(tags, "READY=1")) {
+
                 log_debug_unit(u->id, "%s: got READY=1", u->id);
-                service_enter_start_post(s);
+                s->notify_state = NOTIFY_READY;
+
+                /* Type=notify services inform us about completed
+                 * initialization with READY=1 */
+                if (s->type == SERVICE_NOTIFY && s->state == SERVICE_START)
+                        service_enter_start_post(s);
+
+                /* Sending READY=1 while we are reloading informs us
+                 * that the reloading is complete */
+                if (s->state == SERVICE_RELOAD && s->control_pid == 0)
+                        service_enter_running(s, SERVICE_SUCCESS);
+
+                notify_dbus = true;
+        }
+
+        /* Interpret STOPPING= */
+        if (strv_find(tags, "STOPPING=1")) {
+
+                log_debug_unit(u->id, "%s: got STOPPING=1", u->id);
+                s->notify_state = NOTIFY_STOPPING;
+
+                if (s->state == SERVICE_RUNNING)
+                        service_enter_stop_by_notify(s);
+
                 notify_dbus = true;
         }
 
@@ -2798,6 +2868,15 @@ static const char* const notify_access_table[_NOTIFY_ACCESS_MAX] = {
 
 DEFINE_STRING_TABLE_LOOKUP(notify_access, NotifyAccess);
 
+static const char* const notify_state_table[_NOTIFY_STATE_MAX] = {
+        [NOTIFY_UNKNOWN] = "unknown",
+        [NOTIFY_READY] = "ready",
+        [NOTIFY_RELOADING] = "reloading",
+        [NOTIFY_STOPPING] = "stopping",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(notify_state, NotifyState);
+
 static const char* const service_result_table[_SERVICE_RESULT_MAX] = {
         [SERVICE_SUCCESS] = "success",
         [SERVICE_FAILURE_RESOURCES] = "resources",
diff --git a/src/core/service.h b/src/core/service.h
index 686cf4b0bd..0227321d99 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -91,6 +91,15 @@ typedef enum NotifyAccess {
         _NOTIFY_ACCESS_INVALID = -1
 } NotifyAccess;
 
+typedef enum NotifyState {
+        NOTIFY_UNKNOWN,
+        NOTIFY_READY,
+        NOTIFY_RELOADING,
+        NOTIFY_STOPPING,
+        _NOTIFY_STATE_MAX,
+        _NOTIFY_STATE_INVALID = -1
+} NotifyState;
+
 typedef enum ServiceResult {
         SERVICE_SUCCESS,
         SERVICE_FAILURE_RESOURCES,
@@ -196,6 +205,7 @@ struct Service {
         PathSpec *pid_file_pathspec;
 
         NotifyAccess notify_access;
+        NotifyState notify_state;
 };
 
 extern const UnitVTable service_vtable;
@@ -219,6 +229,9 @@ ServiceExecCommand service_exec_command_from_string(const char *s) _pure_;
 const char* notify_access_to_string(NotifyAccess i) _const_;
 NotifyAccess notify_access_from_string(const char *s) _pure_;
 
+const char* notify_state_to_string(NotifyState i) _const_;
+NotifyState notify_state_from_string(const char *s) _pure_;
+
 const char* service_result_to_string(ServiceResult i) _const_;
 ServiceResult service_result_from_string(const char *s) _pure_;
 
diff --git a/src/test/test-daemon.c b/src/test/test-daemon.c
index bcc049b325..7e0ac754d1 100644
--- a/src/test/test-daemon.c
+++ b/src/test/test-daemon.c
@@ -25,13 +25,29 @@
 
 int main(int argc, char*argv[]) {
 
-        sd_notify(0, "STATUS=Starting up");
+        sd_notify(0,
+                  "STATUS=Starting up");
+        sleep(5);
+
+        sd_notify(0,
+                  "STATUS=Running\n"
+                  "READY=1");
+        sleep(5);
+
+        sd_notify(0,
+                  "STATUS=Reloading\n"
+                  "RELOADING=1");
         sleep(5);
+
         sd_notify(0,
                   "STATUS=Running\n"
                   "READY=1");
-        sleep(10);
-        sd_notify(0, "STATUS=Quitting");
+        sleep(5);
+
+        sd_notify(0,
+                  "STATUS=Quitting\n"
+                  "STOPPING=1");
+        sleep(5);
 
         return 0;
 }