timedated: use libsystemd-bus instead of libdbus for bus communication

Among other things this also adds a few things necessary for the change:

- Considerably more powerful error returning APIs in libsystemd-bus

- Adapter for connecting an sd_bus to an sd_event

- As I reworked the PolicyKit logic to the new library I also made it
  asynchronous, so that PolicyKit requests of one user cannot block out
  another user anymore.

- We always use the macro names for common bus error. That way it is
  harder to mistype them since the compiler will notice

1 files changed, 378 insertions, 0 deletions

diff --git a/src/libsystemd-bus/bus-util.c b/src/libsystemd-bus/bus-util.c
new file mode 100644
index 0000000000..5a70fae77f
--- /dev/null
+++ b/src/libsystemd-bus/bus-util.c
@@ -0,0 +1,378 @@
+/*-*- 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 "sd-event.h"
+#include "sd-bus.h"
+
+#include "util.h"
+#include "macro.h"
+#include "def.h"
+
+#include "bus-util.h"
+
+static int quit_callback(sd_bus *bus, sd_bus_message *m, void *userdata) {
+        sd_event *e = userdata;
+
+        assert(bus);
+        assert(m);
+        assert(e);
+
+        sd_event_request_quit(e);
+        return 1;
+}
+
+int bus_async_unregister_and_quit(sd_event *e, sd_bus *bus, const char *name) {
+        _cleanup_free_ char *match = NULL;
+        int r;
+
+        assert(e);
+        assert(bus);
+        assert(name);
+
+        r = asprintf(&match, "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameLost',arg0='%s'", name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_add_match(bus, match, quit_callback, e);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_release_name(bus, name);
+        if (r < 0)
+                return r;
+
+        if (r != SD_BUS_NAME_RELEASED)
+                return -EIO;
+
+        return 0;
+}
+
+int bus_event_loop_with_idle(sd_event *e, sd_bus *bus, const char *name, usec_t timeout) {
+        bool exiting = false;
+        int r;
+
+        assert(e);
+        assert(bus);
+        assert(name);
+
+        for (;;) {
+                r = sd_event_get_state(e);
+                if (r < 0)
+                        return r;
+
+                if (r == SD_EVENT_FINISHED)
+                        break;
+
+                r = sd_event_run(e, exiting ? (uint64_t) -1 : 5 * USEC_PER_SEC /* DEFAULT_EXIT_USEC */);
+                if (r < 0)
+                        return r;
+
+                if (r == 0 && !exiting) {
+                        r = bus_async_unregister_and_quit(e, bus, name);
+                        if (r < 0)
+                                return r;
+
+                        exiting = true;
+                }
+        }
+
+        return 0;
+}
+
+int bus_property_get_tristate(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                sd_bus_error *error,
+                void *userdata) {
+
+        int *tristate = userdata;
+        int r;
+
+        r = sd_bus_message_append(reply, "b", *tristate > 0);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int bus_verify_polkit(
+                sd_bus *bus,
+                sd_bus_message *m,
+                const char *action,
+                bool interactive,
+                bool *_challenge,
+                sd_bus_error *e) {
+
+        const char *sender;
+        uid_t uid;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(action);
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EBADMSG;
+
+        r = sd_bus_get_owner_uid(bus, sender, &uid);
+        if (r < 0)
+                return r;
+
+        if (uid == 0)
+                return 1;
+
+#ifdef ENABLE_POLKIT
+        else {
+                _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+                bool authorized = false, challenge = false;
+
+                r = sd_bus_call_method(
+                                bus,
+                                "org.freedesktop.PolicyKit1",
+                                "/org/freedesktop/PolicyKit1/Authority",
+                                "org.freedesktop.PolicyKit1.Authority",
+                                "CheckAuthorization",
+                                e,
+                                &reply,
+                                "(sa{sv})sa{ss}us",
+                                "system-bus-name", 1, "name", "s", sender,
+                                action,
+                                0,
+                                interactive ? 1 : 0,
+                                "");
+
+                if (r < 0) {
+                        /* Treat no PK available as access denied */
+                        if (sd_bus_error_has_name(e, SD_BUS_ERROR_SERVICE_UNKNOWN)) {
+                                sd_bus_error_free(e);
+                                return -EACCES;
+                        }
+
+                        return r;
+                }
+
+                r = sd_bus_message_read(reply, "(bb)", &authorized, &challenge);
+                if (r < 0)
+                        return r;
+
+                if (authorized)
+                        return 1;
+
+                if (_challenge) {
+                        *_challenge = challenge;
+                        return 0;
+                }
+        }
+#endif
+
+        return -EACCES;
+}
+
+#ifdef ENABLE_POLKIT
+
+typedef struct AsyncPolkitQuery {
+        sd_bus_message *request, *reply;
+        sd_bus_message_handler_t callback;
+        void *userdata;
+        uint64_t serial;
+} AsyncPolkitQuery;
+
+static int async_polkit_callback(sd_bus *bus, sd_bus_message *reply, void *userdata) {
+        AsyncPolkitQuery *q = userdata;
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(q);
+
+        q->reply = sd_bus_message_ref(reply);
+        q->serial = 0;
+
+        m = sd_bus_message_ref(q->request);
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        r = q->callback(bus, m, q->userdata);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static void async_polkit_query_free(sd_bus *b, AsyncPolkitQuery *q) {
+
+        if (!q)
+                return;
+
+        if (q->serial >  0 && b)
+                sd_bus_send_with_reply_cancel(b, q->serial);
+
+        sd_bus_message_unref(q->request);
+        sd_bus_message_unref(q->reply);
+        free(q);
+}
+
+#endif
+
+int bus_verify_polkit_async(
+                sd_bus *bus,
+                Hashmap **registry,
+                sd_bus_message *m,
+                const char *action,
+                bool interactive,
+                sd_bus_error *error,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+#ifdef ENABLE_POLKIT
+        _cleanup_bus_message_unref_ sd_bus_message *pk = NULL;
+        AsyncPolkitQuery *q;
+#endif
+        const char *sender;
+        uid_t uid;
+        int r;
+
+        assert(bus);
+        assert(registry);
+        assert(m);
+        assert(action);
+
+#ifdef ENABLE_POLKIT
+        q = hashmap_remove(*registry, m);
+        if (q) {
+                bool authorized, challenge;
+
+                /* This is the second invocation of this function, and
+                 * there's already a response from polkit, let's
+                 * process it */
+                assert(q->reply);
+
+                if (sd_bus_message_is_method_error(q->reply, NULL)) {
+                        const sd_bus_error *e;
+
+                        /* Treat no PK available as access denied */
+                        if (sd_bus_message_is_method_error(q->reply, SD_BUS_ERROR_SERVICE_UNKNOWN)) {
+                                async_polkit_query_free(bus, q);
+                                return -EACCES;
+                        }
+
+                        e = sd_bus_message_get_error(q->reply);
+                        sd_bus_error_copy(error, e);
+                        r = sd_bus_error_get_errno(e);
+
+                        async_polkit_query_free(bus, q);
+                        return r;
+                }
+
+                r = sd_bus_message_enter_container(q->reply, 'r', "bba{ss}");
+                if (r >= 0)
+                        r = sd_bus_message_read(q->reply, "bb", &authorized, &challenge);
+
+                async_polkit_query_free(bus, q);
+
+                if (r < 0)
+                        return r;
+
+                if (authorized)
+                        return 1;
+
+                return -EACCES;
+        }
+#endif
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EBADMSG;
+
+        r = sd_bus_get_owner_uid(bus, sender, &uid);
+        if (r < 0)
+                return r;
+
+        if (uid == 0)
+                return 1;
+#ifdef ENABLE_POLKIT
+
+        r = hashmap_ensure_allocated(registry, trivial_hash_func, trivial_compare_func);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.PolicyKit1",
+                        "/org/freedesktop/PolicyKit1/Authority",
+                        "org.freedesktop.PolicyKit1.Authority",
+                        "CheckAuthorization",
+                        &pk);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(
+                        pk,
+                        "(sa{sv})sa{ss}us",
+                        "system-bus-name", 1, "name", "s", sender,
+                        action,
+                        0,
+                        interactive ? 1 : 0,
+                        "");
+        if (r < 0)
+                return r;
+
+        q = new0(AsyncPolkitQuery, 1);
+        if (!q)
+                return -ENOMEM;
+
+        q->request = sd_bus_message_ref(m);
+        q->callback = callback;
+        q->userdata = userdata;
+
+        r = hashmap_put(*registry, m, q);
+        if (r < 0) {
+                async_polkit_query_free(bus, q);
+                return r;
+        }
+
+        r = sd_bus_send_with_reply(bus, pk, async_polkit_callback, q, 0, &q->serial);
+        if (r < 0)
+                return r;
+
+        return 0;
+#endif
+
+        return -EACCES;
+}
+
+void bus_verify_polkit_async_registry_free(sd_bus *bus, Hashmap *registry) {
+#ifdef ENABLE_POLKIT
+        AsyncPolkitQuery *q;
+
+        while ((q = hashmap_steal_first(registry)))
+                async_polkit_query_free(bus, q);
+
+        hashmap_free(registry);
+#endif
+}