libsystemd-bus: add lightweight object vtable implementation for exposing objects on the bus

This adds a lightweight scheme how to define interfaces in static fixed
arrays which then can be easily registered on a bus connection. This
makes it much easier to write bus services.

This automatically handles implementation of the Properties,
ObjectManager, and Introspection bus interfaces.

1 files changed, 374 insertions, 0 deletions

diff --git a/src/libsystemd-bus/test-bus-objects.c b/src/libsystemd-bus/test-bus-objects.c
new file mode 100644
index 0000000000..a95789fe9c
--- /dev/null
+++ b/src/libsystemd-bus/test-bus-objects.c
@@ -0,0 +1,374 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  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.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "log.h"
+#include "util.h"
+#include "macro.h"
+#include "strv.h"
+
+#include "sd-bus.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+
+/* Test:
+ *
+ *   sd_bus_add_object_manager()
+ *   sd_bus_emit_properties_changed()
+ *
+ *   Add in:
+ *
+ *   automatic properties
+ *   node hierarchy updates during dispatching
+ *   emit_interfaces_added/emit_interfaces_removed
+ *
+ */
+
+struct context {
+        int fds[2];
+        bool quit;
+        char *something;
+};
+
+static int something_handler(sd_bus *bus, sd_bus_message *m, void *userdata) {
+        struct context *c = userdata;
+        const char *s;
+        char *n = NULL;
+        int r;
+
+        r = sd_bus_message_read(m, "s", &s);
+        assert_se(r > 0);
+
+        n = strjoin("<<<", s, ">>>", NULL);
+        assert_se(n);
+
+        free(c->something);
+        c->something = n;
+
+        log_info("AlterSomething() called, got %s, returning %s", s, n);
+
+        r = sd_bus_reply_method_return(bus, m, "s", n);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int exit_handler(sd_bus *bus, sd_bus_message *m, void *userdata) {
+        struct context *c = userdata;
+        int r;
+
+        c->quit = true;
+
+        log_info("Exit called");
+
+        r = sd_bus_reply_method_return(bus, m, "");
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int get_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, sd_bus_error *error, void *userdata) {
+        struct context *c = userdata;
+        int r;
+
+        log_info("property get for %s called", property);
+
+        r = sd_bus_message_append(reply, "s", c->something);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int set_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, sd_bus_error *error, void *userdata) {
+        struct context *c = userdata;
+        const char *s;
+        char *n;
+        int r;
+
+        log_info("property set for %s called", property);
+
+        r = sd_bus_message_read(value, "s", &s);
+        assert_se(r >= 0);
+
+        n = strdup(s);
+        assert_se(n);
+
+        free(c->something);
+        c->something = n;
+
+        return 1;
+}
+
+static int value_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, sd_bus_error *error, void *userdata) {
+        _cleanup_free_ char *s = NULL;
+        const char *x;
+        int r;
+
+        assert_se(asprintf(&s, "object %p, path %s", userdata, path) >= 0);
+        r = sd_bus_message_append(reply, "s", s);
+        assert_se(r >= 0);
+
+        assert_se(x = startswith(path, "/value/"));
+
+        assert_se(PTR_TO_UINT(userdata) == 30);
+
+
+        return 1;
+}
+
+static const sd_bus_vtable vtable[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("AlterSomething", "s", "s", 0, something_handler),
+        SD_BUS_METHOD("Exit", "", "", 0, exit_handler),
+        SD_BUS_WRITABLE_PROPERTY("Something", "s", get_handler, set_handler, 0, 0),
+        SD_BUS_VTABLE_END
+};
+
+static const sd_bus_vtable vtable2[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_PROPERTY("Value", "s", value_handler, 10, 0),
+        SD_BUS_VTABLE_END
+};
+
+static int enumerator_callback(sd_bus *b, const char *path, char ***nodes, void *userdata) {
+
+        if (object_path_startswith("/value", path))
+                assert_se(*nodes = strv_new("/value/a", "/value/b", "/value/c", NULL));
+
+        return 1;
+}
+
+static void *server(void *p) {
+        struct context *c = p;
+        sd_bus *bus = NULL;
+        sd_id128_t id;
+        int r;
+
+        c->quit = false;
+
+        assert_se(sd_id128_randomize(&id) >= 0);
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[0], c->fds[0]) >= 0);
+        assert_se(sd_bus_set_server(bus, 1, id) >= 0);
+
+        assert_se(sd_bus_add_object_vtable(bus, "/foo", "org.freedesktop.systemd.test", vtable, c) >= 0);
+        assert_se(sd_bus_add_object_vtable(bus, "/foo", "org.freedesktop.systemd.test2", vtable, c) >= 0);
+        assert_se(sd_bus_add_fallback_vtable(bus, "/value", "org.freedesktop.systemd.ValueTest", vtable2, NULL, UINT_TO_PTR(20)) >= 0);
+        assert_se(sd_bus_add_node_enumerator(bus, "/value", enumerator_callback, NULL) >= 0);
+
+        assert_se(sd_bus_start(bus) >= 0);
+
+        log_error("Entering event loop on server");
+
+        while (!c->quit) {
+                log_error("Loop!");
+
+                r = sd_bus_process(bus, NULL);
+                if (r < 0) {
+                        log_error("Failed to process requests: %s", strerror(-r));
+                        goto fail;
+                }
+
+                if (r == 0) {
+                        r = sd_bus_wait(bus, (uint64_t) -1);
+                        if (r < 0) {
+                                log_error("Failed to wait: %s", strerror(-r));
+                                goto fail;
+                        }
+
+                        continue;
+                }
+        }
+
+        r = 0;
+
+fail:
+        if (bus) {
+                sd_bus_flush(bus);
+                sd_bus_unref(bus);
+        }
+
+        return INT_TO_PTR(r);
+}
+
+static int client(struct context *c) {
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *s;
+        int r;
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[1], c->fds[1]) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AlterSomething", &error, &reply, "s", "hallo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "<<<hallo>>>"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Doesntexist", &error, &reply, "");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, "org.freedesktop.DBus.Error.UnknownMethod"));
+
+        sd_bus_error_free(&error);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AlterSomething", &error, &reply, "as", 1, "hallo");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, "org.freedesktop.DBus.Error.InvalidArgs"));
+
+        sd_bus_error_free(&error);
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "<<<hallo>>>"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_set_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, "s", "test");
+        assert_se(r >= 0);
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "test"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r <= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/value/xuzz", "org.freedesktop.systemd.ValueTest", "Value", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        log_info("read %s", s);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r <= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r <= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r <= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.DBus.Properties", "GetAll", &error, &reply, "s", "");
+        assert_se(r <= 0);
+
+        bus_message_dump(reply);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.DBus.Properties", "GetAll", &error, &reply, "s", "org.freedesktop.systemd.ValueTest2");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, "org.freedesktop.DBus.Error.UnknownInterface"));
+        sd_bus_error_free(&error);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Exit", &error, NULL, "");
+        assert_se(r >= 0);
+
+        sd_bus_flush(bus);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        struct context c;
+        pthread_t s;
+        void *p;
+        int r, q;
+
+        zero(c);
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, c.fds) >= 0);
+
+        r = pthread_create(&s, NULL, server, &c);
+        if (r != 0)
+                return -r;
+
+        r = client(&c);
+
+        q = pthread_join(s, &p);
+        if (q != 0)
+                return -q;
+
+        if (r < 0)
+                return r;
+
+        if (PTR_TO_INT(p) < 0)
+                return PTR_TO_INT(p);
+
+        free(c.something);
+
+        return EXIT_SUCCESS;
+}