Merge pull request #15507 from poettering/bus-log-api

add generic bus interface for setting log level that can be implemented by any daemon

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