sd-bus: Add sd_bus_message_at_end docs

sd-bus: Add sd_bus_set/is_monitor docs

man/rules/meson.build

@@ -277,6 +277,7 @@ manpages = [
   ['sd_bus_message_append_string_iovec', 'sd_bus_message_append_string_space'],
   ''],
  ['sd_bus_message_append_strv', '3', [], ''],
+ ['sd_bus_message_at_end', '3', [], ''],
  ['sd_bus_message_copy', '3', [], ''],
  ['sd_bus_message_dump', '3', [], ''],
  ['sd_bus_message_get_cookie', '3', ['sd_bus_message_get_reply_cookie'], ''],
@@ -409,8 +410,10 @@ manpages = [
   '3',
   ['sd_bus_get_bus_id',
    'sd_bus_is_bus_client',
+   'sd_bus_is_monitor',
    'sd_bus_is_server',
-   'sd_bus_set_bus_client'],
+   'sd_bus_set_bus_client',
+   'sd_bus_set_monitor'],
   ''],
  ['sd_bus_set_watch_bind', '3', ['sd_bus_get_watch_bind'], ''],
  ['sd_bus_slot_get_bus',

man/sd-bus.xml

@@ -84,6 +84,7 @@
 <citerefentry><refentrytitle>sd_bus_get_scope</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_get_tid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_get_unique_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>sd_bus_is_monitor</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_is_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_is_server</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_list_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
@@ -92,6 +93,7 @@
 <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_message_append_string_memfd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_message_append_strv</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>sd_bus_message_at_end</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_message_copy</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_message_dump</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_message_get_cookie</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
@@ -133,6 +135,7 @@
 <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_set_exit_on_disconnect</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_set_method_call_timeout</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>sd_bus_set_monitor</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_set_property</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_set_propertyv</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 <citerefentry><refentrytitle>sd_bus_set_sender</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

man/sd_bus_message_at_end.xml

@@ -0,0 +1,86 @@
+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
+
+<refentry id="sd_bus_message_at_end" xmlns:xi="http://www.w3.org/2001/XInclude">
+  <refentryinfo>
+    <title>sd_bus_message_at_end</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_bus_message_at_end</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_bus_message_at_end</refname>
+
+    <refpurpose>Check if a message has been fully read</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_message_at_end</function></funcdef>
+        <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
+        <paramdef>int <parameter>complete</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_bus_message_at_end()</function> returns whether all data from the currently opened
+    container in <parameter>m</parameter> or all data from all containers in <parameter>m</parameter> has
+    been read. If <parameter>complete</parameter> is zero, this function returns whether all data from the
+    currently opened container has been read. If <parameter>complete</parameter> is non-zero, this function
+    returns whether all data from all containers in <parameter>m</parameter> has been read.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para>If all data from all containers or the current container (depending on the value of
+    <parameter>complete</parameter>) has been read, <function>sd_bus_message_at_end()</function> returns a
+    positive integer. If there is still data left to be read, it returns zero. On failure, it returns a
+    negative errno-style error code.</para>
+
+    <refsect2>
+      <title>Errors</title>
+
+      <para>Returned errors may indicate the following problems:</para>
+
+      <variablelist>
+        <varlistentry>
+          <term><constant>-EINVAL</constant></term>
+
+          <listitem><para>The <parameter>m</parameter> parameter is <constant>NULL</constant>.
+          </para></listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><constant>-EPERM</constant></term>
+
+          <listitem><para>The message is not sealed.</para></listitem>
+        </varlistentry>
+      </variablelist>
+    </refsect2>
+  </refsect1>
+
+  <xi:include href="libsystemd-pkgconfig.xml" />
+
+  <refsect1>
+    <title>See Also</title>
+
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+</refentry>

man/sd_bus_set_server.xml

@@ -22,8 +22,10 @@
     <refname>sd_bus_get_bus_id</refname>
     <refname>sd_bus_set_bus_client</refname>
     <refname>sd_bus_is_bus_client</refname>
+    <refname>sd_bus_set_monitor</refname>
+    <refname>sd_bus_is_monitor</refname>
 
-    <refpurpose>Configure direct connection mode for a bus object</refpurpose>
+    <refpurpose>Configure connection mode for a bus object</refpurpose>
   </refnamediv>
 
   <refsynopsisdiv>
@@ -58,61 +60,83 @@
         <funcdef>int <function>sd_bus_is_bus_client</function></funcdef>
         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
       </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_set_monitor</function></funcdef>
+        <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+        <paramdef>int <parameter>b</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_is_monitor</function></funcdef>
+        <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+      </funcprototype>
     </funcsynopsis>
   </refsynopsisdiv>
 
   <refsect1>
     <title>Description</title>
 
-    <para><function>sd_bus_set_server()</function> configures the bus object as a server for direct
+    <para><function>sd_bus_set_server()</function> configures the bus object as a server for direct D-Bus
-    D-Bus connections. <parameter>b</parameter> enables/disables the server mode. If zero, the
+    connections. <parameter>b</parameter> enables/disables the server mode. If zero, the server mode is
-    server mode is disabled. Otherwise, the server mode is enabled. Configuring a bus object as a
+    disabled. Otherwise, the server mode is enabled. Configuring a bus object as a server is required to
-    server is required to allow establishing direct connections between two peers without going via
+    allow establishing direct connections between two peers without going via the D-Bus daemon.
-    the D-Bus daemon. <parameter>id</parameter> must contain a 128-bit integer id for the server. If
+    <parameter>id</parameter> must contain a 128-bit integer id for the server. If clients add a guid field
-    clients add a guid field to their D-Bus address string, the server id must match this guid or
+    to their D-Bus address string, the server id must match this guid or the D-Bus authentication handshake
-    the D-Bus authentication handshake will fail. If no specific id is defined for the server,
+    will fail. If no specific id is defined for the server,
     <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     can be used to generate a random id instead.</para>
 
-    <para><function>sd_bus_is_server()</function> returns whether the server mode is enabled for
+    <para><function>sd_bus_is_server()</function> returns whether the server mode is enabled for the given
-    the given bus object.</para>
+    bus object.</para>
 
     <para><function>sd_bus_get_bus_id()</function> stores the D-Bus server id configured using
-    <function>sd_bus_set_server()</function> (for server bus objects) or received during
+    <function>sd_bus_set_server()</function> (for server bus objects) or received during D-Bus authentication
-    D-Bus authentication (for client bus objects) in <parameter>id</parameter>.</para>
+    (for client bus objects) in <parameter>id</parameter>.</para>
 
-    <para><function>sd_bus_set_bus_client()</function> configures the bus object as a D-Bus daemon
+    <para><function>sd_bus_set_bus_client()</function> configures the bus object as a D-Bus daemon client.
-    client. <parameter>b</parameter> enables/disables the client mode. If zero, the client mode is
+    <parameter>b</parameter> enables/disables the client mode. If zero, the client mode is disabled and the
-    disabled and the bus object should connect directly to a D-Bus server. Otherwise, the client
+    bus object should connect directly to a D-Bus server. Otherwise, the client mode is enabled and the bus
-    mode is enabled and the bus object should connect to a D-Bus daemon. When connecting to an
+    object should connect to a D-Bus daemon. When connecting to an existing bus using any of the functions in
-    existing bus using any of the functions in the
+    the <citerefentry><refentrytitle>sd_bus_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>
-    <citerefentry><refentrytitle>sd_bus_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     family of functions or any of the functions in the
-    <citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry> family
-    family of functions, the bus object is automatically configured as a bus client. However, when
+    of functions, the bus object is automatically configured as a bus client. However, when connecting to a
-    connecting to a D-Bus daemon by calling
+    D-Bus daemon by calling
     <citerefentry><refentrytitle>sd_bus_set_address</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     followed by
-    <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+    <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>, the bus
-    the bus object should be manually configured as a bus client using
+    object should be manually configured as a bus client using <function>sd_bus_set_bus_client()</function>.
-    <function>sd_bus_set_bus_client()</function>. By default, a bus object is not configured as a
+    By default, a bus object is not configured as a D-Bus daemon client.</para>
-    D-Bus daemon client.</para>
+
+    <para><function>sd_bus_is_bus_client()</function> returns whether the client mode is enabled/disabled for
+    the given bus object.</para>
+
+    <para><function>sd_bus_set_monitor()</function> configures the bus object as a D-Bus monitor object.
+    <parameter>b</parameter> enables/disables the monitor mode. If zero, the monitor mode is disabled. If
+    non-zero, the monitor mode is enabled. When the monitor mode is enabled, no messages may be sent via the
+    bus object and it may not expose any objects on the bus. To start monitoring messages, call the
+    <function>org.freedesktop.DBus.Monitoring.BecomeMonitor</function> method of the D-Bus daemon and pass
+    a list of matches indicating which messages to intercept. See
+    <ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html#bus-messages-become-monitor">
+    The D-Bus specification</ulink> for more information.</para>
+
+    <para><function>sd_bus_is_monitor()</function> returns whether the monitor mode is enabled/disabled for
+    the given bus object.</para>
 
-    <para><function>sd_bus_is_bus_client()</function> returns whether the client mode is
-    enabled/disabled for the given bus object.</para>
   </refsect1>
 
   <refsect1>
     <title>Return Value</title>
 
     <para>On success, <function>sd_bus_set_server()</function>,
-    <function>sd_bus_get_bus_id()</function> and <function>sd_bus_set_bus_client()</function> return
+    <function>sd_bus_get_bus_id()</function>, <function>sd_bus_set_bus_client()</function> and
-    a non-negative integer. On failure, they return a negative errno-style error code.</para>
+    <function>sd_bus_set_monitor()</function> return a non-negative integer. On failure, they return a
+    negative errno-style error code.</para>
 
-    <para><function>sd_bus_is_server()</function> and <function>sd_bus_is_bus_client()</function>
+    <para><function>sd_bus_is_server()</function>, <function>sd_bus_is_bus_client()</function> and
-    return a positive integer when the server or client mode is enabled, respectively. Otherwise,
+    <function>sd_bus_is_monitor()</function> return a positive integer when the server or client mode is
-    they return zero.
+    enabled, respectively. Otherwise, they return zero.</para>
-    </para>
 
     <refsect2>
       <title>Errors</title>

man/systemd.nspawn.xml

@@ -469,18 +469,16 @@
       <varlistentry>
         <term><varname>VirtualEthernetExtra=</varname></term>
 
-        <listitem><para>Takes a colon-separated pair of interface
+        <listitem><para>Takes a colon-separated pair of interface names. Configures an additional virtual
-        names. Configures an additional virtual Ethernet connection
+        Ethernet connection (<literal>veth</literal>) between host and the container. The first specified
-        (<literal>veth</literal>) between host and the container. The
+        name is the interface name on the host, the second the interface name in the container. The latter
-        first specified name is the interface name on the host, the
+        may be omitted in which case it is set to the same name as the host side interface. This setting
-        second the interface name in the container. The latter may be
+        implies <varname>Private=yes</varname>. This setting corresponds to the
-        omitted in which case it is set to the same name as the host
+        <option>--network-veth-extra=</option> command line switch, and maybe be used multiple times. It is
-        side interface. This setting implies
+        independent of <varname>VirtualEthernet=</varname>. Note that this option is unrelated to the
-        <varname>Private=yes</varname>. This setting corresponds to
+        <varname>Bridge=</varname> setting below, and thus any connections created this way are not
-        the <option>--network-veth-extra=</option> command line
+        automatically added to any bridge device on the host side. This option is privileged (see
-        switch, and maybe be used multiple times. It is independent of
+        above).</para></listitem>
-        <varname>VirtualEthernet=</varname>. This option is privileged
-        (see above).</para></listitem>
       </varlistentry>
 
       <varlistentry>

src/core/dbus-manager.c

@@ -9,6 +9,7 @@
 #include "architecture.h"
 #include "build.h"
 #include "bus-common-errors.h"
+#include "bus-log-control-api.h"
 #include "bus-util.h"
 #include "dbus-cgroup.h"
 #include "dbus-execute.h"
@@ -50,7 +51,6 @@ BUS_DEFINE_PROPERTY_GET_ENUM(bus_property_get_oom_policy, oom_policy, OOMPolicy)
 static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_version, "s", GIT_VERSION);
 static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_features, "s", SYSTEMD_FEATURES);
 static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_architecture, "s", architecture_to_string(uname_architecture()));
-static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_log_target, "s", log_target_to_string(log_get_target()));
 static BUS_DEFINE_PROPERTY_GET2(property_get_system_state, "s", Manager, manager_state, manager_state_to_string);
 static BUS_DEFINE_PROPERTY_GET_GLOBAL(property_get_timer_slack_nsec, "t", (uint64_t) prctl(PR_GET_TIMERSLACK));
 static BUS_DEFINE_PROPERTY_GET_REF(property_get_hashmap_size, "u", Hashmap *, hashmap_size);
@@ -141,28 +141,6 @@ static int property_set_log_target(
         return 0;
 }
 
-static int property_get_log_level(
-                sd_bus *bus,
-                const char *path,
-                const char *interface,
-                const char *property,
-                sd_bus_message *reply,
-                void *userdata,
-                sd_bus_error *error) {
-
-        _cleanup_free_ char *t = NULL;
-        int r;
-
-        assert(bus);
-        assert(reply);
-
-        r = log_level_to_string_alloc(log_get_max_level(), &t);
-        if (r < 0)
-                return r;
-
-        return sd_bus_message_append(reply, "s", t);
-}
-
 static int property_set_log_level(
                 sd_bus *bus,
                 const char *path,
@@ -2404,8 +2382,8 @@ const sd_bus_vtable bus_manager_vtable[] = {
         BUS_PROPERTY_DUAL_TIMESTAMP("InitRDGeneratorsFinishTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_INITRD_GENERATORS_FINISH]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("InitRDUnitsLoadStartTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_INITRD_UNITS_LOAD_START]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("InitRDUnitsLoadFinishTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_INITRD_UNITS_LOAD_FINISH]), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_WRITABLE_PROPERTY("LogLevel", "s", property_get_log_level, property_set_log_level, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("LogLevel", "s", bus_property_get_log_level, property_set_log_level, 0, 0),
-        SD_BUS_WRITABLE_PROPERTY("LogTarget", "s", property_get_log_target, property_set_log_target, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("LogTarget", "s", bus_property_get_log_target, property_set_log_target, 0, 0),
         SD_BUS_PROPERTY("NNames", "u", property_get_hashmap_size, offsetof(Manager, units), 0),
         SD_BUS_PROPERTY("NFailedUnits", "u", property_get_set_size, offsetof(Manager, failed_units), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
         SD_BUS_PROPERTY("NJobs", "u", property_get_hashmap_size, offsetof(Manager, jobs), 0),
@@ -3044,6 +3022,21 @@ const sd_bus_vtable bus_manager_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
+const sd_bus_vtable bus_manager_log_control_vtable[] = {
+        SD_BUS_VTABLE_START(0),
+
+        /* We define a private version of this interface here, since we want slightly different
+         * implementations for the setters. We'll still use the generic getters however, and we share the
+         * setters with the implementations for the Manager interface above (which pre-dates the generic
+         * service API interface). */
+
+        SD_BUS_WRITABLE_PROPERTY("LogLevel", "s", bus_property_get_log_level, property_set_log_level, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("LogTarget", "s", bus_property_get_log_target, property_set_log_target, 0, 0),
+        SD_BUS_PROPERTY("SyslogIdentifier", "s", bus_property_get_syslog_identifier, 0, 0),
+
+        SD_BUS_VTABLE_END,
+};
+
 static int send_finished(sd_bus *bus, void *userdata) {
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *message = NULL;
         usec_t *times = userdata;

src/core/dbus-manager.h

@@ -6,6 +6,7 @@
 #include "manager.h"
 
 extern const sd_bus_vtable bus_manager_vtable[];
+extern const sd_bus_vtable bus_manager_log_control_vtable[];
 
 void bus_manager_send_finished(Manager *m, usec_t firmware_usec, usec_t loader_usec, usec_t kernel_usec, usec_t initrd_usec, usec_t userspace_usec, usec_t total_usec);
 void bus_manager_send_reloading(Manager *m, bool active);

src/core/dbus.c

@@ -539,6 +539,10 @@ static int bus_setup_api_vtables(Manager *m, sd_bus *bus) {
         if (r < 0)
                 return log_error_errno(r, "Failed to register Manager vtable: %m");
 
+        r = sd_bus_add_object_vtable(bus, NULL, "/org/freedesktop/LogControl1", "org.freedesktop.LogControl1", bus_manager_log_control_vtable, m);
+        if (r < 0)
+                return log_error_errno(r, "Failed to register service API vtable: %m");
+
         r = sd_bus_add_fallback_vtable(bus, NULL, "/org/freedesktop/systemd1/job", "org.freedesktop.systemd1.Job", bus_job_vtable, bus_job_find, m);
         if (r < 0)
                 return log_error_errno(r, "Failed to register Job vtable: %m");

src/core/execute.c

@@ -1820,12 +1820,13 @@ static int build_environment(
 
                 tty_path = exec_context_tty_path(c);
 
-                /* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try to inherit
+                /* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try
-                 * the $TERM set for PID 1. This is useful for containers so that the $TERM the container manager
+                 * to inherit the $TERM set for PID 1. This is useful for containers so that the $TERM the
-                 * passes to PID 1 ends up all the way in the console login shown. */
+                 * container manager passes to PID 1 ends up all the way in the console login shown. */
 
-                if (path_equal(tty_path, "/dev/console") && getppid() == 1)
+                if (path_equal_ptr(tty_path, "/dev/console") && getppid() == 1)
                         term = getenv("TERM");
+
                 if (!term)
                         term = default_term_for_tty(tty_path);
 

src/home/homed-manager.c

@@ -12,6 +12,7 @@
 #include "btrfs-util.h"
 #include "bus-common-errors.h"
 #include "bus-error.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "clean-ipc.h"
 #include "conf-files.h"
@@ -894,6 +895,10 @@ static int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add object manager: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.home1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/hostname/hostnamed.c

@@ -8,6 +8,7 @@
 
 #include "alloc-util.h"
 #include "bus-common-errors.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "def.h"
 #include "env-file-label.h"
@@ -754,6 +755,10 @@ static int connect_bus(Context *c, sd_event *event, sd_bus **_bus) {
         if (r < 0)
                 return log_error_errno(r, "Failed to register object: %m");
 
+        r = bus_log_control_api_register(bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(bus, NULL, "org.freedesktop.hostname1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/import/importd.c

@@ -7,6 +7,7 @@
 
 #include "alloc-util.h"
 #include "bus-common-errors.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "def.h"
 #include "fd-util.h"
@@ -1308,6 +1309,10 @@ static int manager_add_bus_objects(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add transfer enumerator: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.import1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/locale/localed.c

@@ -14,6 +14,7 @@
 
 #include "alloc-util.h"
 #include "bus-error.h"
+#include "bus-log-control-api.h"
 #include "bus-message.h"
 #include "bus-polkit.h"
 #include "def.h"
@@ -724,6 +725,10 @@ static int connect_bus(Context *c, sd_event *event, sd_bus **_bus) {
         if (r < 0)
                 return log_error_errno(r, "Failed to register object: %m");
 
+        r = bus_log_control_api_register(bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(bus, NULL, "org.freedesktop.locale1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/login/logind.c

@@ -9,6 +9,7 @@
 
 #include "alloc-util.h"
 #include "bus-error.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "cgroup-util.h"
 #include "def.h"
@@ -706,6 +707,10 @@ static int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to enable subscription: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.login1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/machine/machined.c

@@ -10,6 +10,7 @@
 
 #include "alloc-util.h"
 #include "bus-error.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "cgroup-util.h"
 #include "dirent-util.h"
@@ -263,6 +264,10 @@ static int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to enable subscription: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.machine1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/network/networkd-manager.c

@@ -11,6 +11,7 @@
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "bus-util.h"
 #include "conf-parser.h"
@@ -165,6 +166,10 @@ int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add network enumerator: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.network1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/portable/portabled.c

@@ -7,6 +7,7 @@
 #include "sd-daemon.h"
 
 #include "alloc-util.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "def.h"
 #include "main-func.h"
@@ -84,6 +85,10 @@ static int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add image enumerator: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.portable1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/resolve/resolvectl.c

@@ -2529,8 +2529,8 @@ static int verb_log_level(int argc, char *argv[], void *userdata) {
                 r = sd_bus_get_property_string(
                                 bus,
                                 "org.freedesktop.resolve1",
-                                "/org/freedesktop/resolve1",
+                                "/org/freedesktop/LogControl1",
-                                "org.freedesktop.resolve1.Manager",
+                                "org.freedesktop.LogControl1",
                                 "LogLevel",
                                 &error,
                                 &level);
@@ -2545,8 +2545,8 @@ static int verb_log_level(int argc, char *argv[], void *userdata) {
                 r = sd_bus_set_property(
                                 bus,
                                 "org.freedesktop.resolve1",
-                                "/org/freedesktop/resolve1",
+                                "/org/freedesktop/LogControl1",
-                                "org.freedesktop.resolve1.Manager",
+                                "org.freedesktop.LogControl1",
                                 "LogLevel",
                                 &error,
                                 "s",

src/resolve/resolved-bus.c

@@ -2,6 +2,7 @@
 
 #include "alloc-util.h"
 #include "bus-common-errors.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "bus-util.h"
 #include "dns-domain.h"
@@ -1836,57 +1837,6 @@ static int bus_method_unregister_service(sd_bus_message *message, void *userdata
         return call_dnssd_method(m, message, bus_dnssd_method_unregister, error);
 }
 
-static int property_get_log_level(
-                sd_bus *bus,
-                const char *path,
-                const char *interface,
-                const char *property,
-                sd_bus_message *reply,
-                void *userdata,
-                sd_bus_error *error) {
-
-        _cleanup_free_ char *t = NULL;
-        int r;
-
-        assert(bus);
-        assert(reply);
-
-        r = log_level_to_string_alloc(log_get_max_level(), &t);
-        if (r < 0)
-                return r;
-
-        return sd_bus_message_append(reply, "s", t);
-}
-
-static int property_set_log_level(
-                sd_bus *bus,
-                const char *path,
-                const char *interface,
-                const char *property,
-                sd_bus_message *value,
-                void *userdata,
-                sd_bus_error *error) {
-
-        const char *t;
-        int r;
-
-        assert(bus);
-        assert(value);
-
-        r = sd_bus_message_read(value, "s", &t);
-        if (r < 0)
-                return r;
-
-        r = log_level_from_string(t);
-        if (r < 0)
-                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid log level '%s'", t);
-
-        log_info("Setting log level to %s.", t);
-        log_set_max_level(r);
-
-        return 0;
-}
-
 static const sd_bus_vtable resolve_vtable[] = {
         SD_BUS_VTABLE_START(0),
         SD_BUS_PROPERTY("LLMNRHostname", "s", NULL, offsetof(Manager, llmnr_hostname), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
@@ -1905,8 +1855,6 @@ static const sd_bus_vtable resolve_vtable[] = {
         SD_BUS_PROPERTY("DNSSECNegativeTrustAnchors", "as", bus_property_get_ntas, 0, 0),
         SD_BUS_PROPERTY("DNSStubListener", "s", bus_property_get_dns_stub_listener_mode, offsetof(Manager, dns_stub_listener_mode), 0),
 
-        SD_BUS_WRITABLE_PROPERTY("LogLevel", "s", property_get_log_level, property_set_log_level, 0, 0),
-
         SD_BUS_METHOD_WITH_NAMES("ResolveHostname",
                                  "isit",
                                  SD_BUS_PARAM(ifindex)
@@ -2121,6 +2069,10 @@ int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to register dnssd enumerator: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.resolve1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/shared/bus-log-control-api.c

@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "alloc-util.h"
+#include "bus-log-control-api.h"
+#include "bus-util.h"
+#include "log.h"
+#include "sd-bus.h"
+#include "syslog-util.h"
+
+int bus_property_get_log_level(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                void *userdata,
+                sd_bus_error *error) {
+
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        assert(bus);
+        assert(reply);
+
+        r = log_level_to_string_alloc(log_get_max_level(), &t);
+        if (r < 0)
+                return r;
+
+        return sd_bus_message_append(reply, "s", t);
+}
+
+int bus_property_set_log_level(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *value,
+                void *userdata,
+                sd_bus_error *error) {
+
+        const char *t;
+        int r;
+
+        assert(bus);
+        assert(value);
+
+        r = sd_bus_message_read(value, "s", &t);
+        if (r < 0)
+                return r;
+
+        r = log_level_from_string(t);
+        if (r < 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid log level '%s'", t);
+
+        log_info("Setting log level to %s.", t);
+        log_set_max_level(r);
+
+        return 0;
+}
+
+BUS_DEFINE_PROPERTY_GET_GLOBAL(bus_property_get_log_target, "s", log_target_to_string(log_get_target()));
+
+int bus_property_set_log_target(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *value,
+                void *userdata,
+                sd_bus_error *error) {
+
+        LogTarget target;
+        const char *t;
+        int r;
+
+        assert(bus);
+        assert(value);
+
+        r = sd_bus_message_read(value, "s", &t);
+        if (r < 0)
+                return r;
+
+        target = log_target_from_string(t);
+        if (target < 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid log target '%s'", t);
+
+        log_info("Setting log target to %s.", log_target_to_string(target));
+        log_set_target(target);
+        log_open();
+
+        return 0;
+}
+
+BUS_DEFINE_PROPERTY_GET_GLOBAL(bus_property_get_syslog_identifier, "s", program_invocation_short_name);
+
+static const sd_bus_vtable log_control_vtable[] = {
+        SD_BUS_VTABLE_START(0),
+
+        SD_BUS_WRITABLE_PROPERTY("LogLevel", "s", bus_property_get_log_level, bus_property_set_log_level, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("LogTarget", "s", bus_property_get_log_target, bus_property_set_log_target, 0, 0),
+        SD_BUS_PROPERTY("SyslogIdentifier", "s", bus_property_get_syslog_identifier, 0, 0),
+
+        /* One of those days we might want to add a similar, second interface to cover common service
+         * operations such as Reload(), Reexecute(), Exit() …  and maybe some properties exposing version
+         * number and other meta-data of the service. */
+
+        SD_BUS_VTABLE_END,
+};
+
+int bus_log_control_api_register(sd_bus *bus) {
+        int r;
+
+        r = sd_bus_add_object_vtable(
+                        bus,
+                        NULL,
+                        "/org/freedesktop/LogControl1",
+                        "org.freedesktop.LogControl1",
+                        log_control_vtable, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to register service API object: %m");
+
+        return 0;
+}

src/shared/bus-log-control-api.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "sd-bus.h"
+
+int bus_log_control_api_register(sd_bus *bus);
+
+int bus_property_get_log_level(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error);
+int bus_property_set_log_level(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, void *userdata, sd_bus_error *error);
+
+int bus_property_get_log_target(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error);
+int bus_property_set_log_target(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error);
+
+int bus_property_get_syslog_identifier(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error);

src/shared/meson.build

@@ -23,14 +23,16 @@ shared_sources = files('''
         bpf-program.h
         bridge-util.c
         bridge-util.h
+        bus-log-control-api.c
+        bus-log-control-api.h
+        bus-polkit.c
+        bus-polkit.h
         bus-unit-procs.c
         bus-unit-procs.h
         bus-unit-util.c
         bus-unit-util.h
         bus-util.c
         bus-util.h
-        bus-polkit.c
-        bus-polkit.h
         bus-wait-for-jobs.c
         bus-wait-for-jobs.h
         bus-wait-for-units.c

src/timedate/timedated.c

@@ -12,6 +12,7 @@
 #include "alloc-util.h"
 #include "bus-common-errors.h"
 #include "bus-error.h"
+#include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "clock-util.h"
 #include "conf-files.h"
@@ -1100,6 +1101,10 @@ static int connect_bus(Context *c, sd_event *event, sd_bus **_bus) {
         if (r < 0)
                 return log_error_errno(r, "Failed to register object: %m");
 
+        r = bus_log_control_api_register(bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(bus, NULL, "org.freedesktop.timedate1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");

src/timesync/timesyncd-bus.c

@@ -4,6 +4,7 @@
 
 #include "alloc-util.h"
 #include "bus-internal.h"
+#include "bus-log-control-api.h"
 #include "bus-protocol.h"
 #include "bus-util.h"
 #include "in-addr-util.h"
@@ -189,6 +190,10 @@ int manager_connect_bus(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to add manager object vtable: %m");
 
+        r = bus_log_control_api_register(m->bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_request_name_async(m->bus, NULL, "org.freedesktop.timesync1", 0, NULL, NULL);
         if (r < 0)
                 return log_error_errno(r, "Failed to request name: %m");