Adding upstream version 252.22.upstream/252.22

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4405 insertions, 0 deletions

diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
new file mode 100644
index 0000000..3c91dd3
--- /dev/null
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -0,0 +1,4405 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <endian.h>
+#include <netdb.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+
+#include "af-list.h"
+#include "alloc-util.h"
+#include "bus-container.h"
+#include "bus-control.h"
+#include "bus-internal.h"
+#include "bus-kernel.h"
+#include "bus-label.h"
+#include "bus-message.h"
+#include "bus-objects.h"
+#include "bus-protocol.h"
+#include "bus-slot.h"
+#include "bus-socket.h"
+#include "bus-track.h"
+#include "bus-type.h"
+#include "cgroup-util.h"
+#include "def.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "glyph-util.h"
+#include "hexdecoct.h"
+#include "hostname-util.h"
+#include "io-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "missing_syscall.h"
+#include "missing_threads.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+
+#define log_debug_bus_message(m)                                         \
+        do {                                                             \
+                sd_bus_message *_mm = (m);                               \
+                log_debug("Got message type=%s sender=%s destination=%s path=%s interface=%s member=%s cookie=%" PRIu64 " reply_cookie=%" PRIu64 " signature=%s error-name=%s error-message=%s", \
+                          strna(bus_message_type_to_string(_mm->header->type)), \
+                          strna(sd_bus_message_get_sender(_mm)),         \
+                          strna(sd_bus_message_get_destination(_mm)),    \
+                          strna(sd_bus_message_get_path(_mm)),           \
+                          strna(sd_bus_message_get_interface(_mm)),      \
+                          strna(sd_bus_message_get_member(_mm)),         \
+                          BUS_MESSAGE_COOKIE(_mm),                       \
+                          _mm->reply_cookie,                             \
+                          strna(_mm->root_container.signature),          \
+                          strna(_mm->error.name),                        \
+                          strna(_mm->error.message));                    \
+        } while (false)
+
+static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec);
+static void bus_detach_io_events(sd_bus *b);
+
+static thread_local sd_bus *default_system_bus = NULL;
+static thread_local sd_bus *default_user_bus = NULL;
+static thread_local sd_bus *default_starter_bus = NULL;
+
+static sd_bus **bus_choose_default(int (**bus_open)(sd_bus **)) {
+        const char *e;
+
+        /* Let's try our best to reuse another cached connection. If
+         * the starter bus type is set, connect via our normal
+         * connection logic, ignoring $DBUS_STARTER_ADDRESS, so that
+         * we can share the connection with the user/system default
+         * bus. */
+
+        e = secure_getenv("DBUS_STARTER_BUS_TYPE");
+        if (e) {
+                if (streq(e, "system")) {
+                        if (bus_open)
+                                *bus_open = sd_bus_open_system;
+                        return &default_system_bus;
+                } else if (STR_IN_SET(e, "user", "session")) {
+                        if (bus_open)
+                                *bus_open = sd_bus_open_user;
+                        return &default_user_bus;
+                }
+        }
+
+        /* No type is specified, so we have not other option than to
+         * use the starter address if it is set. */
+        e = secure_getenv("DBUS_STARTER_ADDRESS");
+        if (e) {
+                if (bus_open)
+                        *bus_open = sd_bus_open;
+                return &default_starter_bus;
+        }
+
+        /* Finally, if nothing is set use the cached connection for
+         * the right scope */
+
+        if (cg_pid_get_owner_uid(0, NULL) >= 0) {
+                if (bus_open)
+                        *bus_open = sd_bus_open_user;
+                return &default_user_bus;
+        } else {
+                if (bus_open)
+                        *bus_open = sd_bus_open_system;
+                return &default_system_bus;
+        }
+}
+
+sd_bus *bus_resolve(sd_bus *bus) {
+        switch ((uintptr_t) bus) {
+        case (uintptr_t) SD_BUS_DEFAULT:
+                return *(bus_choose_default(NULL));
+        case (uintptr_t) SD_BUS_DEFAULT_USER:
+                return default_user_bus;
+        case (uintptr_t) SD_BUS_DEFAULT_SYSTEM:
+                return default_system_bus;
+        default:
+                return bus;
+        }
+}
+
+void bus_close_io_fds(sd_bus *b) {
+        assert(b);
+
+        bus_detach_io_events(b);
+
+        if (b->input_fd != b->output_fd)
+                safe_close(b->output_fd);
+        b->output_fd = b->input_fd = safe_close(b->input_fd);
+}
+
+void bus_close_inotify_fd(sd_bus *b) {
+        assert(b);
+
+        b->inotify_event_source = sd_event_source_disable_unref(b->inotify_event_source);
+
+        b->inotify_fd = safe_close(b->inotify_fd);
+        b->inotify_watches = mfree(b->inotify_watches);
+        b->n_inotify_watches = 0;
+}
+
+static void bus_reset_queues(sd_bus *b) {
+        assert(b);
+
+        while (b->rqueue_size > 0)
+                bus_message_unref_queued(b->rqueue[--b->rqueue_size], b);
+
+        b->rqueue = mfree(b->rqueue);
+
+        while (b->wqueue_size > 0)
+                bus_message_unref_queued(b->wqueue[--b->wqueue_size], b);
+
+        b->wqueue = mfree(b->wqueue);
+}
+
+static sd_bus* bus_free(sd_bus *b) {
+        sd_bus_slot *s;
+
+        assert(b);
+        assert(!b->track_queue);
+        assert(!b->tracks);
+
+        b->state = BUS_CLOSED;
+
+        sd_bus_detach_event(b);
+
+        while ((s = b->slots)) {
+                /* At this point only floating slots can still be
+                 * around, because the non-floating ones keep a
+                 * reference to the bus, and we thus couldn't be
+                 * destructing right now... We forcibly disconnect the
+                 * slots here, so that they still can be referenced by
+                 * apps, but are dead. */
+
+                assert(s->floating);
+                bus_slot_disconnect(s, true);
+        }
+
+        if (b->default_bus_ptr)
+                *b->default_bus_ptr = NULL;
+
+        bus_close_io_fds(b);
+        bus_close_inotify_fd(b);
+
+        free(b->label);
+        free(b->groups);
+        free(b->rbuffer);
+        free(b->unique_name);
+        free(b->auth_buffer);
+        free(b->address);
+        free(b->machine);
+        free(b->description);
+        free(b->patch_sender);
+
+        free(b->exec_path);
+        strv_free(b->exec_argv);
+
+        close_many(b->fds, b->n_fds);
+        free(b->fds);
+
+        bus_reset_queues(b);
+
+        ordered_hashmap_free_free(b->reply_callbacks);
+        prioq_free(b->reply_callbacks_prioq);
+
+        assert(b->match_callbacks.type == BUS_MATCH_ROOT);
+        bus_match_free(&b->match_callbacks);
+
+        hashmap_free_free(b->vtable_methods);
+        hashmap_free_free(b->vtable_properties);
+
+        assert(hashmap_isempty(b->nodes));
+        hashmap_free(b->nodes);
+
+        bus_flush_memfd(b);
+
+        assert_se(pthread_mutex_destroy(&b->memfd_cache_mutex) == 0);
+
+        return mfree(b);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus*, bus_free);
+
+_public_ int sd_bus_new(sd_bus **ret) {
+        _cleanup_free_ sd_bus *b = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        b = new(sd_bus, 1);
+        if (!b)
+                return -ENOMEM;
+
+        *b = (sd_bus) {
+                .n_ref = 1,
+                .input_fd = -1,
+                .output_fd = -1,
+                .inotify_fd = -1,
+                .message_version = 1,
+                .creds_mask = SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME,
+                .accept_fd = true,
+                .original_pid = getpid_cached(),
+                .n_groups = SIZE_MAX,
+                .close_on_exit = true,
+                .ucred = UCRED_INVALID,
+        };
+
+        /* We guarantee that wqueue always has space for at least one entry */
+        if (!GREEDY_REALLOC(b->wqueue, 1))
+                return -ENOMEM;
+
+        assert_se(pthread_mutex_init(&b->memfd_cache_mutex, NULL) == 0);
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_set_address(sd_bus *bus, const char *address) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(address, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return free_and_strdup(&bus->address, address);
+}
+
+_public_ int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(input_fd >= 0, -EBADF);
+        assert_return(output_fd >= 0, -EBADF);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->input_fd = input_fd;
+        bus->output_fd = output_fd;
+        return 0;
+}
+
+_public_ int sd_bus_set_exec(sd_bus *bus, const char *path, char *const *argv) {
+        _cleanup_strv_free_ char **a = NULL;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(path, -EINVAL);
+        assert_return(!strv_isempty(argv), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        a = strv_copy(argv);
+        if (!a)
+                return -ENOMEM;
+
+        r = free_and_strdup(&bus->exec_path, path);
+        if (r < 0)
+                return r;
+
+        return strv_free_and_replace(bus->exec_argv, a);
+}
+
+_public_ int sd_bus_set_bus_client(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus->patch_sender, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->bus_client = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_monitor(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->is_monitor = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_fds(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->accept_fd = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_timestamp(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!IN_SET(bus->state, BUS_CLOSING, BUS_CLOSED), -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        /* This is not actually supported by any of our transports these days, but we do honour it for synthetic
+         * replies, and maybe one day classic D-Bus learns this too */
+        bus->attach_timestamp = !!b;
+
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t mask) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(mask <= _SD_BUS_CREDS_ALL, -EINVAL);
+        assert_return(!IN_SET(bus->state, BUS_CLOSING, BUS_CLOSED), -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->creds_mask, mask, b);
+
+        /* The well knowns we need unconditionally, so that matches can work */
+        bus->creds_mask |= SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME;
+
+        return 0;
+}
+
+_public_ int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(b || sd_id128_equal(server_id, SD_ID128_NULL), -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->is_server = !!b;
+        bus->server_id = server_id;
+        return 0;
+}
+
+_public_ int sd_bus_set_anonymous(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->anonymous_auth = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_trusted(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->trusted = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_description(sd_bus *bus, const char *description) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return free_and_strdup(&bus->description, description);
+}
+
+_public_ int sd_bus_set_allow_interactive_authorization(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->allow_interactive_authorization = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_allow_interactive_authorization(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->allow_interactive_authorization;
+}
+
+_public_ int sd_bus_set_watch_bind(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->watch_bind = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_watch_bind(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->watch_bind;
+}
+
+_public_ int sd_bus_set_connected_signal(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->connected_signal = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_connected_signal(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->connected_signal;
+}
+
+static int synthesize_connected_signal(sd_bus *bus) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        /* If enabled, synthesizes a local "Connected" signal mirroring the local "Disconnected" signal. This is called
+         * whenever we fully established a connection, i.e. after the authorization phase, and after receiving the
+         * Hello() reply. Or in other words, whenever we enter BUS_RUNNING state.
+         *
+         * This is useful so that clients can start doing stuff whenever the connection is fully established in a way
+         * that works independently from whether we connected to a full bus or just a direct connection. */
+
+        if (!bus->connected_signal)
+                return 0;
+
+        r = sd_bus_message_new_signal(
+                        bus,
+                        &m,
+                        "/org/freedesktop/DBus/Local",
+                        "org.freedesktop.DBus.Local",
+                        "Connected");
+        if (r < 0)
+                return r;
+
+        bus_message_set_sender_local(bus, m);
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        /* Insert at the very front */
+        memmove(bus->rqueue + 1, bus->rqueue, sizeof(sd_bus_message*) * bus->rqueue_size);
+        bus->rqueue[0] = bus_message_ref_queued(m, bus);
+        bus->rqueue_size++;
+
+        return 0;
+}
+
+void bus_set_state(sd_bus *bus, enum bus_state state) {
+        static const char* const table[_BUS_STATE_MAX] = {
+                [BUS_UNSET]          = "UNSET",
+                [BUS_WATCH_BIND]     = "WATCH_BIND",
+                [BUS_OPENING]        = "OPENING",
+                [BUS_AUTHENTICATING] = "AUTHENTICATING",
+                [BUS_HELLO]          = "HELLO",
+                [BUS_RUNNING]        = "RUNNING",
+                [BUS_CLOSING]        = "CLOSING",
+                [BUS_CLOSED]         = "CLOSED",
+        };
+
+        assert(bus);
+        assert(state < _BUS_STATE_MAX);
+
+        if (state == bus->state)
+                return;
+
+        log_debug("Bus %s: changing state %s %s %s", strna(bus->description),
+                  table[bus->state], special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), table[state]);
+        bus->state = state;
+}
+
+static int hello_callback(sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        const char *s;
+        sd_bus *bus;
+        int r;
+
+        assert(reply);
+        bus = reply->bus;
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_HELLO, BUS_CLOSING));
+
+        r = sd_bus_message_get_errno(reply);
+        if (r > 0) {
+                r = -r;
+                goto fail;
+        }
+
+        r = sd_bus_message_read(reply, "s", &s);
+        if (r < 0)
+                goto fail;
+
+        if (!service_name_is_valid(s) || s[0] != ':') {
+                r = -EBADMSG;
+                goto fail;
+        }
+
+        r = free_and_strdup(&bus->unique_name, s);
+        if (r < 0)
+                goto fail;
+
+        if (bus->state == BUS_HELLO) {
+                bus_set_state(bus, BUS_RUNNING);
+
+                r = synthesize_connected_signal(bus);
+                if (r < 0)
+                        goto fail;
+        }
+
+        return 1;
+
+fail:
+        /* When Hello() failed, let's propagate this in two ways: first we return the error immediately here,
+         * which is the propagated up towards the event loop. Let's also invalidate the connection, so that
+         * if the user then calls back into us again we won't wait any longer. */
+
+        bus_set_state(bus, BUS_CLOSING);
+        return r;
+}
+
+static int bus_send_hello(sd_bus *bus) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        if (!bus->bus_client)
+                return 0;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "Hello");
+        if (r < 0)
+                return r;
+
+        return sd_bus_call_async(bus, NULL, m, hello_callback, NULL, 0);
+}
+
+int bus_start_running(sd_bus *bus) {
+        struct reply_callback *c;
+        usec_t n;
+        int r;
+
+        assert(bus);
+        assert(bus->state < BUS_HELLO);
+
+        /* We start all method call timeouts when we enter BUS_HELLO or BUS_RUNNING mode. At this point let's convert
+         * all relative to absolute timestamps. Note that we do not reshuffle the reply callback priority queue since
+         * adding a fixed value to all entries should not alter the internal order. */
+
+        n = now(CLOCK_MONOTONIC);
+        ORDERED_HASHMAP_FOREACH(c, bus->reply_callbacks) {
+                if (c->timeout_usec == 0)
+                        continue;
+
+                c->timeout_usec = usec_add(n, c->timeout_usec);
+        }
+
+        if (bus->bus_client) {
+                bus_set_state(bus, BUS_HELLO);
+                return 1;
+        }
+
+        bus_set_state(bus, BUS_RUNNING);
+
+        r = synthesize_connected_signal(bus);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int parse_address_key(const char **p, const char *key, char **value) {
+        _cleanup_free_ char *r = NULL;
+        size_t l, n = 0;
+        const char *a;
+
+        assert(p);
+        assert(*p);
+        assert(value);
+
+        if (key) {
+                l = strlen(key);
+                if (strncmp(*p, key, l) != 0)
+                        return 0;
+
+                if ((*p)[l] != '=')
+                        return 0;
+
+                if (*value)
+                        return -EINVAL;
+
+                a = *p + l + 1;
+        } else
+                a = *p;
+
+        while (!IN_SET(*a, ';', ',', 0)) {
+                char c;
+
+                if (*a == '%') {
+                        int x, y;
+
+                        x = unhexchar(a[1]);
+                        if (x < 0)
+                                return x;
+
+                        y = unhexchar(a[2]);
+                        if (y < 0)
+                                return y;
+
+                        c = (char) ((x << 4) | y);
+                        a += 3;
+                } else {
+                        c = *a;
+                        a++;
+                }
+
+                if (!GREEDY_REALLOC(r, n + 2))
+                        return -ENOMEM;
+
+                r[n++] = c;
+        }
+
+        if (!r) {
+                r = strdup("");
+                if (!r)
+                        return -ENOMEM;
+        } else
+                r[n] = 0;
+
+        if (*a == ',')
+                a++;
+
+        *p = a;
+
+        free_and_replace(*value, r);
+
+        return 1;
+}
+
+static void skip_address_key(const char **p) {
+        assert(p);
+        assert(*p);
+
+        *p += strcspn(*p, ",");
+
+        if (**p == ',')
+                (*p)++;
+}
+
+static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *path = NULL, *abstract = NULL;
+        size_t l;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "abstract", &abstract);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!path && !abstract)
+                return -EINVAL;
+
+        if (path && abstract)
+                return -EINVAL;
+
+        if (path) {
+                l = strlen(path);
+                if (l >= sizeof(b->sockaddr.un.sun_path)) /* We insist on NUL termination */
+                        return -E2BIG;
+
+                b->sockaddr.un = (struct sockaddr_un) {
+                        .sun_family = AF_UNIX,
+                };
+
+                memcpy(b->sockaddr.un.sun_path, path, l);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l + 1;
+
+        } else {
+                assert(abstract);
+
+                l = strlen(abstract);
+                if (l >= sizeof(b->sockaddr.un.sun_path) - 1) /* We insist on NUL termination */
+                        return -E2BIG;
+
+                b->sockaddr.un = (struct sockaddr_un) {
+                        .sun_family = AF_UNIX,
+                };
+
+                memcpy(b->sockaddr.un.sun_path+1, abstract, l);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
+        }
+
+        b->is_local = true;
+
+        return 0;
+}
+
+static int parse_tcp_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
+        int r;
+        struct addrinfo *result, hints = {
+                .ai_socktype = SOCK_STREAM,
+        };
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "host", &host);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "port", &port);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "family", &family);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!host || !port)
+                return -EINVAL;
+
+        if (family) {
+                hints.ai_family = af_from_ipv4_ipv6(family);
+                if (hints.ai_family == AF_UNSPEC)
+                        return -EINVAL;
+        }
+
+        r = getaddrinfo(host, port, &hints, &result);
+        if (r == EAI_SYSTEM)
+                return -errno;
+        else if (r != 0)
+                return -EADDRNOTAVAIL;
+
+        memcpy(&b->sockaddr, result->ai_addr, result->ai_addrlen);
+        b->sockaddr_size = result->ai_addrlen;
+
+        freeaddrinfo(result);
+
+        b->is_local = false;
+
+        return 0;
+}
+
+static int parse_exec_address(sd_bus *b, const char **p, char **guid) {
+        char *path = NULL;
+        unsigned n_argv = 0, j;
+        char **argv = NULL;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
+
+                if (startswith(*p, "argv")) {
+                        unsigned ul;
+
+                        errno = 0;
+                        ul = strtoul(*p + 4, (char**) p, 10);
+                        if (errno > 0 || **p != '=' || ul > 256) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        (*p)++;
+
+                        if (ul >= n_argv) {
+                                if (!GREEDY_REALLOC0(argv, ul + 2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                n_argv = ul + 1;
+                        }
+
+                        r = parse_address_key(p, NULL, argv + ul);
+                        if (r < 0)
+                                goto fail;
+
+                        continue;
+                }
+
+                skip_address_key(p);
+        }
+
+        if (!path) {
+                r = -EINVAL;
+                goto fail;
+        }
+
+        /* Make sure there are no holes in the array, with the
+         * exception of argv[0] */
+        for (j = 1; j < n_argv; j++)
+                if (!argv[j]) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+        if (argv && argv[0] == NULL) {
+                argv[0] = strdup(path);
+                if (!argv[0]) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        b->exec_path = path;
+        b->exec_argv = argv;
+
+        b->is_local = false;
+
+        return 0;
+
+fail:
+        for (j = 0; j < n_argv; j++)
+                free(argv[j]);
+
+        free(argv);
+        free(path);
+        return r;
+}
+
+static int parse_container_unix_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *machine = NULL, *pid = NULL;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "machine", &machine);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "pid", &pid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!machine == !pid)
+                return -EINVAL;
+
+        if (machine) {
+                if (!hostname_is_valid(machine, VALID_HOSTNAME_DOT_HOST))
+                        return -EINVAL;
+
+                free_and_replace(b->machine, machine);
+        } else
+                b->machine = mfree(b->machine);
+
+        if (pid) {
+                r = parse_pid(pid, &b->nspid);
+                if (r < 0)
+                        return r;
+        } else
+                b->nspid = 0;
+
+        b->sockaddr.un = (struct sockaddr_un) {
+                .sun_family = AF_UNIX,
+                /* Note that we use the old /var/run prefix here, to increase compatibility with really old containers */
+                .sun_path = "/var/run/dbus/system_bus_socket",
+        };
+        b->sockaddr_size = SOCKADDR_UN_LEN(b->sockaddr.un);
+        b->is_local = false;
+
+        return 0;
+}
+
+static void bus_reset_parsed_address(sd_bus *b) {
+        assert(b);
+
+        zero(b->sockaddr);
+        b->sockaddr_size = 0;
+        b->exec_argv = strv_free(b->exec_argv);
+        b->exec_path = mfree(b->exec_path);
+        b->server_id = SD_ID128_NULL;
+        b->machine = mfree(b->machine);
+        b->nspid = 0;
+}
+
+static int bus_parse_next_address(sd_bus *b) {
+        _cleanup_free_ char *guid = NULL;
+        const char *a;
+        int r;
+
+        assert(b);
+
+        if (!b->address)
+                return 0;
+        if (b->address[b->address_index] == 0)
+                return 0;
+
+        bus_reset_parsed_address(b);
+
+        a = b->address + b->address_index;
+
+        while (*a != 0) {
+
+                if (*a == ';') {
+                        a++;
+                        continue;
+                }
+
+                if (startswith(a, "unix:")) {
+                        a += 5;
+
+                        r = parse_unix_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+                        break;
+
+                } else if (startswith(a, "tcp:")) {
+
+                        a += 4;
+                        r = parse_tcp_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                } else if (startswith(a, "unixexec:")) {
+
+                        a += 9;
+                        r = parse_exec_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                } else if (startswith(a, "x-machine-unix:")) {
+
+                        a += 15;
+                        r = parse_container_unix_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                }
+
+                a = strchr(a, ';');
+                if (!a)
+                        return 0;
+        }
+
+        if (guid) {
+                r = sd_id128_from_string(guid, &b->server_id);
+                if (r < 0)
+                        return r;
+        }
+
+        b->address_index = a - b->address;
+        return 1;
+}
+
+static void bus_kill_exec(sd_bus *bus) {
+        if (!pid_is_valid(bus->busexec_pid))
+                return;
+
+        sigterm_wait(TAKE_PID(bus->busexec_pid));
+}
+
+static int bus_start_address(sd_bus *b) {
+        int r;
+
+        assert(b);
+
+        for (;;) {
+                bus_close_io_fds(b);
+                bus_close_inotify_fd(b);
+
+                bus_kill_exec(b);
+
+                /* If you provide multiple different bus-addresses, we
+                 * try all of them in order and use the first one that
+                 * succeeds. */
+
+                if (b->exec_path)
+                        r = bus_socket_exec(b);
+                else if ((b->nspid > 0 || b->machine) && b->sockaddr.sa.sa_family != AF_UNSPEC)
+                        r = bus_container_connect_socket(b);
+                else if (b->sockaddr.sa.sa_family != AF_UNSPEC)
+                        r = bus_socket_connect(b);
+                else
+                        goto next;
+
+                if (r >= 0) {
+                        int q;
+
+                        q = bus_attach_io_events(b);
+                        if (q < 0)
+                                return q;
+
+                        q = bus_attach_inotify_event(b);
+                        if (q < 0)
+                                return q;
+
+                        return r;
+                }
+
+                b->last_connect_error = -r;
+
+        next:
+                r = bus_parse_next_address(b);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return b->last_connect_error > 0 ? -b->last_connect_error : -ECONNREFUSED;
+        }
+}
+
+int bus_next_address(sd_bus *b) {
+        assert(b);
+
+        bus_reset_parsed_address(b);
+        return bus_start_address(b);
+}
+
+static int bus_start_fd(sd_bus *b) {
+        struct stat st;
+        int r;
+
+        assert(b);
+        assert(b->input_fd >= 0);
+        assert(b->output_fd >= 0);
+
+        if (DEBUG_LOGGING) {
+                _cleanup_free_ char *pi = NULL, *po = NULL;
+                (void) fd_get_path(b->input_fd, &pi);
+                (void) fd_get_path(b->output_fd, &po);
+                log_debug("sd-bus: starting bus%s%s on fds %d/%d (%s, %s)...",
+                          b->description ? " " : "", strempty(b->description),
+                          b->input_fd, b->output_fd,
+                          pi ?: "???", po ?: "???");
+        }
+
+        r = fd_nonblock(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        r = fd_cloexec(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        if (b->input_fd != b->output_fd) {
+                r = fd_nonblock(b->output_fd, true);
+                if (r < 0)
+                        return r;
+
+                r = fd_cloexec(b->output_fd, true);
+                if (r < 0)
+                        return r;
+        }
+
+        if (fstat(b->input_fd, &st) < 0)
+                return -errno;
+
+        return bus_socket_take_fd(b);
+}
+
+_public_ int sd_bus_start(sd_bus *bus) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus_set_state(bus, BUS_OPENING);
+
+        if (bus->is_server && bus->bus_client)
+                return -EINVAL;
+
+        if (bus->input_fd >= 0)
+                r = bus_start_fd(bus);
+        else if (bus->address || bus->sockaddr.sa.sa_family != AF_UNSPEC || bus->exec_path || bus->machine)
+                r = bus_start_address(bus);
+        else
+                return -EINVAL;
+
+        if (r < 0) {
+                sd_bus_close(bus);
+                return r;
+        }
+
+        return bus_send_hello(bus);
+}
+
+_public_ int sd_bus_open_with_description(sd_bus **ret, const char *description) {
+        const char *e;
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        /* Let's connect to the starter bus if it is set, and
+         * otherwise to the bus that is appropriate for the scope
+         * we are running in */
+
+        e = secure_getenv("DBUS_STARTER_BUS_TYPE");
+        if (e) {
+                if (streq(e, "system"))
+                        return sd_bus_open_system_with_description(ret, description);
+                else if (STR_IN_SET(e, "session", "user"))
+                        return sd_bus_open_user_with_description(ret, description);
+        }
+
+        e = secure_getenv("DBUS_STARTER_ADDRESS");
+        if (!e) {
+                if (cg_pid_get_owner_uid(0, NULL) >= 0)
+                        return sd_bus_open_user_with_description(ret, description);
+                else
+                        return sd_bus_open_system_with_description(ret, description);
+        }
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_set_address(b, e);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* We don't know whether the bus is trusted or not, so better
+         * be safe, and authenticate everything */
+        b->trusted = false;
+        b->is_local = false;
+        b->creds_mask |= SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_EFFECTIVE_CAPS;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open(sd_bus **ret) {
+        return sd_bus_open_with_description(ret, NULL);
+}
+
+int bus_set_address_system(sd_bus *b) {
+        const char *e;
+        int r;
+
+        assert(b);
+
+        e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
+
+        r = sd_bus_set_address(b, e ?: DEFAULT_SYSTEM_BUS_ADDRESS);
+        if (r >= 0)
+                b->is_system = true;
+        return r;
+}
+
+_public_ int sd_bus_open_system_with_description(sd_bus **ret, const char *description) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        if (description) {
+                r = sd_bus_set_description(b, description);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_set_address_system(b);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* Let's do per-method access control on the system bus. We
+         * need the caller's UID and capability set for that. */
+        b->trusted = false;
+        b->creds_mask |= SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_EFFECTIVE_CAPS;
+        b->is_local = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open_system(sd_bus **ret) {
+        return sd_bus_open_system_with_description(ret, NULL);
+}
+
+int bus_set_address_user(sd_bus *b) {
+        const char *a;
+        _cleanup_free_ char *_a = NULL;
+        int r;
+
+        assert(b);
+
+        a = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
+        if (!a) {
+                const char *e;
+                _cleanup_free_ char *ee = NULL;
+
+                e = secure_getenv("XDG_RUNTIME_DIR");
+                if (!e)
+                        return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
+                                               "sd-bus: $XDG_RUNTIME_DIR not set, cannot connect to user bus.");
+
+                ee = bus_address_escape(e);
+                if (!ee)
+                        return -ENOMEM;
+
+                if (asprintf(&_a, DEFAULT_USER_BUS_ADDRESS_FMT, ee) < 0)
+                        return -ENOMEM;
+                a = _a;
+        }
+
+        r = sd_bus_set_address(b, a);
+        if (r >= 0)
+                b->is_user = true;
+        return r;
+}
+
+_public_ int sd_bus_open_user_with_description(sd_bus **ret, const char *description) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        if (description) {
+                r = sd_bus_set_description(b, description);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_set_address_user(b);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* We don't do any per-method access control on the user bus. */
+        b->trusted = true;
+        b->is_local = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open_user(sd_bus **ret) {
+        return sd_bus_open_user_with_description(ret, NULL);
+}
+
+int bus_set_address_system_remote(sd_bus *b, const char *host) {
+        _cleanup_free_ char *e = NULL;
+        char *m = NULL, *c = NULL, *a, *rbracket = NULL, *p = NULL;
+
+        assert(b);
+        assert(host);
+
+        /* Skip ":"s in ipv6 addresses */
+        if (*host == '[') {
+                char *t;
+
+                rbracket = strchr(host, ']');
+                if (!rbracket)
+                        return -EINVAL;
+                t = strndupa_safe(host + 1, rbracket - host - 1);
+                e = bus_address_escape(t);
+                if (!e)
+                        return -ENOMEM;
+        } else if ((a = strchr(host, '@'))) {
+                if (*(a + 1) == '[') {
+                        _cleanup_free_ char *t = NULL;
+
+                        rbracket = strchr(a + 1, ']');
+                        if (!rbracket)
+                                return -EINVAL;
+                        t = new0(char, strlen(host));
+                        if (!t)
+                                return -ENOMEM;
+                        strncat(t, host, a - host + 1);
+                        strncat(t, a + 2, rbracket - a - 2);
+                        e = bus_address_escape(t);
+                        if (!e)
+                                return -ENOMEM;
+                } else if (*(a + 1) == '\0' || strchr(a + 1, '@'))
+                        return -EINVAL;
+        }
+
+        /* Let's see if a port was given */
+        m = strchr(rbracket ? rbracket + 1 : host, ':');
+        if (m) {
+                char *t;
+                bool got_forward_slash = false;
+
+                p = m + 1;
+
+                t = strchr(p, '/');
+                if (t) {
+                        p = strndupa_safe(p, t - p);
+                        got_forward_slash = true;
+                }
+
+                if (!in_charset(p, "0123456789") || *p == '\0') {
+                        if (!hostname_is_valid(p, 0) || got_forward_slash)
+                                return -EINVAL;
+
+                        m = TAKE_PTR(p);
+                        goto interpret_port_as_machine_old_syntax;
+                }
+        }
+
+        /* Let's see if a machine was given */
+        m = strchr(rbracket ? rbracket + 1 : host, '/');
+        if (m) {
+                m++;
+interpret_port_as_machine_old_syntax:
+                /* Let's make sure this is not a port of some kind,
+                 * and is a valid machine name. */
+                if (!in_charset(m, "0123456789") && hostname_is_valid(m, 0))
+                        c = strjoina(",argv", p ? "7" : "5", "=--machine=", m);
+        }
+
+        if (!e) {
+                char *t;
+
+                t = strndupa_safe(host, strcspn(host, ":/"));
+
+                e = bus_address_escape(t);
+                if (!e)
+                        return -ENOMEM;
+        }
+
+        a = strjoin("unixexec:path=ssh,argv1=-xT", p ? ",argv2=-p,argv3=" : "", strempty(p),
+                                ",argv", p ? "4" : "2", "=--,argv", p ? "5" : "3", "=", e,
+                                ",argv", p ? "6" : "4", "=systemd-stdio-bridge", c);
+        if (!a)
+                return -ENOMEM;
+
+        return free_and_replace(b->address, a);
+}
+
+_public_ int sd_bus_open_system_remote(sd_bus **ret, const char *host) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(host, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = bus_set_address_system_remote(b, host);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+        b->trusted = false;
+        b->is_system = true;
+        b->is_local = false;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+int bus_set_address_machine(sd_bus *b, bool user, const char *machine) {
+        _cleanup_free_ char *a = NULL;
+        const char *rhs;
+
+        assert(b);
+        assert(machine);
+
+        rhs = strchr(machine, '@');
+        if (rhs || user) {
+                _cleanup_free_ char *u = NULL, *eu = NULL, *erhs = NULL;
+
+                /* If there's an "@" in the container specification, we'll connect as a user specified at its
+                 * left hand side, which is useful in combination with user=true. This isn't as trivial as it
+                 * might sound: it's not sufficient to enter the container and connect to some socket there,
+                 * since the --user socket path depends on $XDG_RUNTIME_DIR which is set via PAM. Thus, to be
+                 * able to connect, we need to have a PAM session. Our way out?  We use systemd-run to get
+                 * into the container and acquire a PAM session there, and then invoke systemd-stdio-bridge
+                 * in it, which propagates the bus transport to us. */
+
+                if (rhs) {
+                        if (rhs > machine)
+                                u = strndup(machine, rhs - machine);
+                        else
+                                u = getusername_malloc(); /* Empty user name, let's use the local one */
+                        if (!u)
+                                return -ENOMEM;
+
+                        eu = bus_address_escape(u);
+                        if (!eu)
+                                return -ENOMEM;
+
+                        rhs++;
+                } else {
+                        /* No "@" specified but we shall connect to the user instance? Then assume root (and
+                         * not a user named identically to the calling one). This means:
+                         *
+                         *     --machine=foobar --user    → connect to user bus of root user in container "foobar"
+                         *     --machine=@foobar --user   → connect to user bus of user named like the calling user in container "foobar"
+                         *
+                         * Why? so that behaviour for "--machine=foobar --system" is roughly similar to
+                         * "--machine=foobar --user": both times we unconditionally connect as root user
+                         * regardless what the calling user is. */
+
+                        rhs = machine;
+                }
+
+                if (!isempty(rhs)) {
+                        erhs = bus_address_escape(rhs);
+                        if (!erhs)
+                                return -ENOMEM;
+                }
+
+                /* systemd-run -M… -PGq --wait -pUser=… -pPAMName=login systemd-stdio-bridge */
+
+                a = strjoin("unixexec:path=systemd-run,"
+                            "argv1=-M", erhs ?: ".host", ","
+                            "argv2=-PGq,"
+                            "argv3=--wait,"
+                            "argv4=-pUser%3d", eu ?: "root", ",",
+                            "argv5=-pPAMName%3dlogin,"
+                            "argv6=systemd-stdio-bridge");
+                if (!a)
+                        return -ENOMEM;
+
+                if (user) {
+                        /* Ideally we'd use the "--user" switch to systemd-stdio-bridge here, but it's only
+                         * available in recent systemd versions. Using the "-p" switch with the explicit path
+                         * is a working alternative, and is compatible with older versions, hence that's what
+                         * we use here. */
+                        if (!strextend(&a, ",argv7=-punix:path%3d%24%7bXDG_RUNTIME_DIR%7d/bus"))
+                                return -ENOMEM;
+                }
+        } else {
+                _cleanup_free_ char *e = NULL;
+
+                /* Just a container name, we can go the simple way, and just join the container, and connect
+                 * to the well-known path of the system bus there. */
+
+                e = bus_address_escape(machine);
+                if (!e)
+                        return -ENOMEM;
+
+                a = strjoin("x-machine-unix:machine=", e);
+                if (!a)
+                        return -ENOMEM;
+        }
+
+        return free_and_replace(b->address, a);
+}
+
+static int user_and_machine_valid(const char *user_and_machine) {
+        const char *h;
+
+        /* Checks if a container specification in the form "user@container" or just "container" is valid.
+         *
+         * If the "@" syntax is used we'll allow either the "user" or the "container" part to be omitted, but
+         * not both. */
+
+        h = strchr(user_and_machine, '@');
+        if (!h)
+                h = user_and_machine;
+        else {
+                _cleanup_free_ char *user = NULL;
+
+                user = strndup(user_and_machine, h - user_and_machine);
+                if (!user)
+                        return -ENOMEM;
+
+                if (!isempty(user) && !valid_user_group_name(user, VALID_USER_RELAX | VALID_USER_ALLOW_NUMERIC))
+                        return false;
+
+                h++;
+
+                if (isempty(h))
+                        return !isempty(user);
+        }
+
+        return hostname_is_valid(h, VALID_HOSTNAME_DOT_HOST);
+}
+
+static int user_and_machine_equivalent(const char *user_and_machine) {
+        _cleanup_free_ char *un = NULL;
+        const char *f;
+
+        /* Returns true if the specified user+machine name are actually equivalent to our own identity and
+         * our own host. If so we can shortcut things.  Why bother? Because that way we don't have to fork
+         * off short-lived worker processes that are then unavailable for authentication and logging in the
+         * peer. Moreover joining a namespace requires privileges. If we are in the right namespace anyway,
+         * we can avoid permission problems thus. */
+
+        assert(user_and_machine);
+
+        /* Omitting the user name means that we shall use the same user name as we run as locally, which
+         * means we'll end up on the same host, let's shortcut */
+        if (streq(user_and_machine, "@.host"))
+                return true;
+
+        /* Otherwise, if we are root, then we can also allow the ".host" syntax, as that's the user this
+         * would connect to. */
+        uid_t uid = geteuid();
+
+        if (uid == 0 && STR_IN_SET(user_and_machine, ".host", "root@.host", "0@.host"))
+                return true;
+
+        /* Otherwise, we have to figure out our user id and name, and compare things with that. */
+        char buf[DECIMAL_STR_MAX(uid_t)];
+        xsprintf(buf, UID_FMT, uid);
+
+        f = startswith(user_and_machine, buf);
+        if (!f) {
+                un = getusername_malloc();
+                if (!un)
+                        return -ENOMEM;
+
+                f = startswith(user_and_machine, un);
+                if (!f)
+                        return false;
+        }
+
+        return STR_IN_SET(f, "@", "@.host");
+}
+
+_public_ int sd_bus_open_system_machine(sd_bus **ret, const char *user_and_machine) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(user_and_machine, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (user_and_machine_equivalent(user_and_machine))
+                return sd_bus_open_system(ret);
+
+        r = user_and_machine_valid(user_and_machine);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = bus_set_address_machine(b, false, user_and_machine);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+        b->is_system = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open_user_machine(sd_bus **ret, const char *user_and_machine) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(user_and_machine, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        /* Shortcut things if we'd end up on this host and as the same user.  */
+        if (user_and_machine_equivalent(user_and_machine))
+                return sd_bus_open_user(ret);
+
+        r = user_and_machine_valid(user_and_machine);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = bus_set_address_machine(b, true, user_and_machine);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+        b->trusted = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ void sd_bus_close(sd_bus *bus) {
+        if (!bus)
+                return;
+        if (bus->state == BUS_CLOSED)
+                return;
+        if (bus_pid_changed(bus))
+                return;
+
+        /* Don't leave ssh hanging around */
+        bus_kill_exec(bus);
+
+        bus_set_state(bus, BUS_CLOSED);
+
+        sd_bus_detach_event(bus);
+
+        /* Drop all queued messages so that they drop references to
+         * the bus object and the bus may be freed */
+        bus_reset_queues(bus);
+
+        bus_close_io_fds(bus);
+        bus_close_inotify_fd(bus);
+}
+
+_public_ sd_bus *sd_bus_close_unref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        sd_bus_close(bus);
+
+        return sd_bus_unref(bus);
+}
+
+_public_ sd_bus* sd_bus_flush_close_unref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        /* Have to do this before flush() to prevent hang */
+        bus_kill_exec(bus);
+        sd_bus_flush(bus);
+
+        return sd_bus_close_unref(bus);
+}
+
+void bus_enter_closing(sd_bus *bus) {
+        assert(bus);
+
+        if (!IN_SET(bus->state, BUS_WATCH_BIND, BUS_OPENING, BUS_AUTHENTICATING, BUS_HELLO, BUS_RUNNING))
+                return;
+
+        bus_set_state(bus, BUS_CLOSING);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus, sd_bus, bus_free);
+
+_public_ int sd_bus_is_open(sd_bus *bus) {
+        if (!bus)
+                return 0;
+
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return BUS_IS_OPEN(bus->state);
+}
+
+_public_ int sd_bus_is_ready(sd_bus *bus) {
+        if (!bus)
+                return 0;
+
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->state == BUS_RUNNING;
+}
+
+_public_ int sd_bus_can_send(sd_bus *bus, char type) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (type == SD_BUS_TYPE_UNIX_FD) {
+                if (!bus->accept_fd)
+                        return 0;
+
+                r = bus_ensure_running(bus);
+                if (r < 0)
+                        return r;
+
+                return bus->can_fds;
+        }
+
+        return bus_type_is_valid(type);
+}
+
+_public_ int sd_bus_get_bus_id(sd_bus *bus, sd_id128_t *id) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(id, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        *id = bus->server_id;
+        return 0;
+}
+
+#define COOKIE_CYCLED (UINT32_C(1) << 31)
+
+static uint64_t cookie_inc(uint64_t cookie) {
+
+        /* Stay within the 32bit range, since classic D-Bus can't deal with more */
+        if (cookie >= UINT32_MAX)
+                return COOKIE_CYCLED; /* Don't go back to zero, but use the highest bit for checking
+                                       * whether we are looping. */
+
+        return cookie + 1;
+}
+
+static int next_cookie(sd_bus *b) {
+        uint64_t new_cookie;
+
+        assert(b);
+
+        new_cookie = cookie_inc(b->cookie);
+
+        /* Small optimization: don't bother with checking for cookie reuse until we overran cookiespace at
+         * least once, but then do it thorougly. */
+        if (FLAGS_SET(new_cookie, COOKIE_CYCLED)) {
+                uint32_t i;
+
+                /* Check if the cookie is currently in use. If so, pick the next one */
+                for (i = 0; i < COOKIE_CYCLED; i++) {
+                        if (!ordered_hashmap_contains(b->reply_callbacks, &new_cookie))
+                                goto good;
+
+                        new_cookie = cookie_inc(new_cookie);
+                }
+
+                /* Can't fulfill request */
+                return -EBUSY;
+        }
+
+good:
+        b->cookie = new_cookie;
+        return 0;
+}
+
+static int bus_seal_message(sd_bus *b, sd_bus_message *m, usec_t timeout) {
+        int r;
+
+        assert(b);
+        assert(m);
+
+        if (m->sealed) {
+                /* If we copy the same message to multiple
+                 * destinations, avoid using the same cookie
+                 * numbers. */
+                b->cookie = MAX(b->cookie, BUS_MESSAGE_COOKIE(m));
+                return 0;
+        }
+
+        if (timeout == 0) {
+                r = sd_bus_get_method_call_timeout(b, &timeout);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!m->sender && b->patch_sender) {
+                r = sd_bus_message_set_sender(m, b->patch_sender);
+                if (r < 0)
+                        return r;
+        }
+
+        r = next_cookie(b);
+        if (r < 0)
+                return r;
+
+        return sd_bus_message_seal(m, b->cookie, timeout);
+}
+
+static int bus_remarshal_message(sd_bus *b, sd_bus_message **m) {
+        bool remarshal = false;
+
+        assert(b);
+
+        /* wrong packet version */
+        if (b->message_version != 0 && b->message_version != (*m)->header->version)
+                remarshal = true;
+
+        /* wrong packet endianness */
+        if (b->message_endian != 0 && b->message_endian != (*m)->header->endian)
+                remarshal = true;
+
+        return remarshal ? bus_message_remarshal(b, m) : 0;
+}
+
+int bus_seal_synthetic_message(sd_bus *b, sd_bus_message *m) {
+        assert(b);
+        assert(m);
+
+        /* Fake some timestamps, if they were requested, and not
+         * already initialized */
+        if (b->attach_timestamp) {
+                if (m->realtime <= 0)
+                        m->realtime = now(CLOCK_REALTIME);
+
+                if (m->monotonic <= 0)
+                        m->monotonic = now(CLOCK_MONOTONIC);
+        }
+
+        /* The bus specification says the serial number cannot be 0,
+         * hence let's fill something in for synthetic messages. Since
+         * synthetic messages might have a fake sender and we don't
+         * want to interfere with the real sender's serial numbers we
+         * pick a fixed, artificial one. */
+        return sd_bus_message_seal(m, UINT32_MAX, 0);
+}
+
+static int bus_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        r = bus_socket_write_message(bus, m, idx);
+        if (r <= 0)
+                return r;
+
+        if (*idx >= BUS_MESSAGE_SIZE(m))
+                log_debug("Sent message type=%s sender=%s destination=%s path=%s interface=%s member=%s cookie=%" PRIu64 " reply_cookie=%" PRIu64 " signature=%s error-name=%s error-message=%s",
+                          bus_message_type_to_string(m->header->type),
+                          strna(sd_bus_message_get_sender(m)),
+                          strna(sd_bus_message_get_destination(m)),
+                          strna(sd_bus_message_get_path(m)),
+                          strna(sd_bus_message_get_interface(m)),
+                          strna(sd_bus_message_get_member(m)),
+                          BUS_MESSAGE_COOKIE(m),
+                          m->reply_cookie,
+                          strna(m->root_container.signature),
+                          strna(m->error.name),
+                          strna(m->error.message));
+
+        return r;
+}
+
+static int dispatch_wqueue(sd_bus *bus) {
+        int r, ret = 0;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        while (bus->wqueue_size > 0) {
+
+                r = bus_write_message(bus, bus->wqueue[0], &bus->windex);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        /* Didn't do anything this time */
+                        return ret;
+                else if (bus->windex >= BUS_MESSAGE_SIZE(bus->wqueue[0])) {
+                        /* Fully written. Let's drop the entry from
+                         * the queue.
+                         *
+                         * This isn't particularly optimized, but
+                         * well, this is supposed to be our worst-case
+                         * buffer only, and the socket buffer is
+                         * supposed to be our primary buffer, and if
+                         * it got full, then all bets are off
+                         * anyway. */
+
+                        bus->wqueue_size--;
+                        bus_message_unref_queued(bus->wqueue[0], bus);
+                        memmove(bus->wqueue, bus->wqueue + 1, sizeof(sd_bus_message*) * bus->wqueue_size);
+                        bus->windex = 0;
+
+                        ret = 1;
+                }
+        }
+
+        return ret;
+}
+
+static int bus_read_message(sd_bus *bus) {
+        assert(bus);
+
+        return bus_socket_read_message(bus);
+}
+
+int bus_rqueue_make_room(sd_bus *bus) {
+        assert(bus);
+
+        if (bus->rqueue_size >= BUS_RQUEUE_MAX)
+                return -ENOBUFS;
+
+        if (!GREEDY_REALLOC(bus->rqueue, bus->rqueue_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static void rqueue_drop_one(sd_bus *bus, size_t i) {
+        assert(bus);
+        assert(i < bus->rqueue_size);
+
+        bus_message_unref_queued(bus->rqueue[i], bus);
+        memmove(bus->rqueue + i, bus->rqueue + i + 1, sizeof(sd_bus_message*) * (bus->rqueue_size - i - 1));
+        bus->rqueue_size--;
+}
+
+static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
+        int r, ret = 0;
+
+        assert(bus);
+        assert(m);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        for (;;) {
+                if (bus->rqueue_size > 0) {
+                        /* Dispatch a queued message */
+                        *m = sd_bus_message_ref(bus->rqueue[0]);
+                        rqueue_drop_one(bus, 0);
+                        return 1;
+                }
+
+                /* Try to read a new message */
+                r = bus_read_message(bus);
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        *m = NULL;
+                        return ret;
+                }
+
+                ret = 1;
+        }
+}
+
+_public_ int sd_bus_send(sd_bus *bus, sd_bus_message *_m, uint64_t *cookie) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (m->n_fds > 0) {
+                r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -EOPNOTSUPP;
+        }
+
+        /* If the cookie number isn't kept, then we know that no reply
+         * is expected */
+        if (!cookie && !m->sealed)
+                m->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = bus_seal_message(bus, m, 0);
+        if (r < 0)
+                return r;
+
+        /* Remarshall if we have to. This will possibly unref the
+         * message and place a replacement in m */
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                return r;
+
+        /* If this is a reply and no reply was requested, then let's
+         * suppress this, if we can */
+        if (m->dont_send)
+                goto finish;
+
+        if (IN_SET(bus->state, BUS_RUNNING, BUS_HELLO) && bus->wqueue_size <= 0) {
+                size_t idx = 0;
+
+                r = bus_write_message(bus, m, &idx);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                return -ECONNRESET;
+                        }
+
+                        return r;
+                }
+
+                if (idx < BUS_MESSAGE_SIZE(m))  {
+                        /* Wasn't fully written. So let's remember how
+                         * much was written. Note that the first entry
+                         * of the wqueue array is always allocated so
+                         * that we always can remember how much was
+                         * written. */
+                        bus->wqueue[0] = bus_message_ref_queued(m, bus);
+                        bus->wqueue_size = 1;
+                        bus->windex = idx;
+                }
+
+        } else {
+                /* Just append it to the queue. */
+
+                if (bus->wqueue_size >= BUS_WQUEUE_MAX)
+                        return -ENOBUFS;
+
+                if (!GREEDY_REALLOC(bus->wqueue, bus->wqueue_size + 1))
+                        return -ENOMEM;
+
+                bus->wqueue[bus->wqueue_size++] = bus_message_ref_queued(m, bus);
+        }
+
+finish:
+        if (cookie)
+                *cookie = BUS_MESSAGE_COOKIE(m);
+
+        return 1;
+}
+
+_public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destination, uint64_t *cookie) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (!streq_ptr(m->destination, destination)) {
+
+                if (!destination)
+                        return -EEXIST;
+
+                r = sd_bus_message_set_destination(m, destination);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_send(bus, m, cookie);
+}
+
+static usec_t calc_elapse(sd_bus *bus, uint64_t usec) {
+        assert(bus);
+
+        assert_cc(sizeof(usec_t) == sizeof(uint64_t));
+
+        if (usec == USEC_INFINITY)
+                return 0;
+
+        /* We start all timeouts the instant we enter BUS_HELLO/BUS_RUNNING state, so that the don't run in parallel
+         * with any connection setup states. Hence, if a method callback is started earlier than that we just store the
+         * relative timestamp, and afterwards the absolute one. */
+
+        if (IN_SET(bus->state, BUS_WATCH_BIND, BUS_OPENING, BUS_AUTHENTICATING))
+                return usec;
+        else
+                return usec_add(now(CLOCK_MONOTONIC), usec);
+}
+
+static int timeout_compare(const void *a, const void *b) {
+        const struct reply_callback *x = a, *y = b;
+
+        if (x->timeout_usec != 0 && y->timeout_usec == 0)
+                return -1;
+
+        if (x->timeout_usec == 0 && y->timeout_usec != 0)
+                return 1;
+
+        return CMP(x->timeout_usec, y->timeout_usec);
+}
+
+_public_ int sd_bus_call_async(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                sd_bus_message *_m,
+                sd_bus_message_handler_t callback,
+                void *userdata,
+                uint64_t usec) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        _cleanup_(sd_bus_slot_unrefp) sd_bus_slot *s = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(!m->sealed || (!!callback == !(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)), -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* If no callback is specified and there's no interest in a slot, then there's no reason to ask for a reply */
+        if (!callback && !slot && !m->sealed)
+                m->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = ordered_hashmap_ensure_allocated(&bus->reply_callbacks, &uint64_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = prioq_ensure_allocated(&bus->reply_callbacks_prioq, timeout_compare);
+        if (r < 0)
+                return r;
+
+        r = bus_seal_message(bus, m, usec);
+        if (r < 0)
+                return r;
+
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                return r;
+
+        if (slot || callback) {
+                s = bus_slot_allocate(bus, !slot, BUS_REPLY_CALLBACK, sizeof(struct reply_callback), userdata);
+                if (!s)
+                        return -ENOMEM;
+
+                s->reply_callback.callback = callback;
+
+                s->reply_callback.cookie = BUS_MESSAGE_COOKIE(m);
+                r = ordered_hashmap_put(bus->reply_callbacks, &s->reply_callback.cookie, &s->reply_callback);
+                if (r < 0) {
+                        s->reply_callback.cookie = 0;
+                        return r;
+                }
+
+                s->reply_callback.timeout_usec = calc_elapse(bus, m->timeout);
+                if (s->reply_callback.timeout_usec != 0) {
+                        r = prioq_put(bus->reply_callbacks_prioq, &s->reply_callback, &s->reply_callback.prioq_idx);
+                        if (r < 0) {
+                                s->reply_callback.timeout_usec = 0;
+                                return r;
+                        }
+                }
+        }
+
+        r = sd_bus_send(bus, m, s ? &s->reply_callback.cookie : NULL);
+        if (r < 0)
+                return r;
+
+        if (slot)
+                *slot = s;
+        s = NULL;
+
+        return r;
+}
+
+int bus_ensure_running(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->state == BUS_RUNNING)
+                return 1;
+
+        for (;;) {
+                if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
+                        return -ENOTCONN;
+
+                r = sd_bus_process(bus, NULL);
+                if (r < 0)
+                        return r;
+                if (bus->state == BUS_RUNNING)
+                        return 1;
+                if (r > 0)
+                        continue;
+
+                r = sd_bus_wait(bus, UINT64_MAX);
+                if (r < 0)
+                        return r;
+        }
+}
+
+_public_ int sd_bus_call(
+                sd_bus *bus,
+                sd_bus_message *_m,
+                uint64_t usec,
+                sd_bus_error *error,
+                sd_bus_message **reply) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        usec_t timeout;
+        uint64_t cookie;
+        size_t i;
+        int r;
+
+        bus_assert_return(m, -EINVAL, error);
+        bus_assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL, error);
+        bus_assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL, error);
+        bus_assert_return(!bus_error_is_dirty(error), -EINVAL, error);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                goto fail;
+
+        i = bus->rqueue_size;
+
+        r = bus_seal_message(bus, m, usec);
+        if (r < 0)
+                goto fail;
+
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_send(bus, m, &cookie);
+        if (r < 0)
+                goto fail;
+
+        timeout = calc_elapse(bus, m->timeout);
+
+        for (;;) {
+                usec_t left;
+
+                while (i < bus->rqueue_size) {
+                        _cleanup_(sd_bus_message_unrefp) sd_bus_message *incoming = NULL;
+
+                        incoming = sd_bus_message_ref(bus->rqueue[i]);
+
+                        if (incoming->reply_cookie == cookie) {
+                                /* Found a match! */
+
+                                rqueue_drop_one(bus, i);
+                                log_debug_bus_message(incoming);
+
+                                if (incoming->header->type == SD_BUS_MESSAGE_METHOD_RETURN) {
+
+                                        if (incoming->n_fds <= 0 || bus->accept_fd) {
+                                                if (reply)
+                                                        *reply = TAKE_PTR(incoming);
+
+                                                return 1;
+                                        }
+
+                                        return sd_bus_error_set(error, SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Reply message contained file descriptors which I couldn't accept. Sorry.");
+
+                                } else if (incoming->header->type == SD_BUS_MESSAGE_METHOD_ERROR)
+                                        return sd_bus_error_copy(error, &incoming->error);
+                                else {
+                                        r = -EIO;
+                                        goto fail;
+                                }
+
+                        } else if (BUS_MESSAGE_COOKIE(incoming) == cookie &&
+                                   bus->unique_name &&
+                                   incoming->sender &&
+                                   streq(bus->unique_name, incoming->sender)) {
+
+                                rqueue_drop_one(bus, i);
+
+                                /* Our own message? Somebody is trying to send its own client a message,
+                                 * let's not dead-lock, let's fail immediately. */
+
+                                r = -ELOOP;
+                                goto fail;
+                        }
+
+                        /* Try to read more, right-away */
+                        i++;
+                }
+
+                r = bus_read_message(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                r = -ECONNRESET;
+                        }
+
+                        goto fail;
+                }
+                if (r > 0)
+                        continue;
+
+                if (timeout > 0) {
+                        usec_t n;
+
+                        n = now(CLOCK_MONOTONIC);
+                        if (n >= timeout) {
+                                r = -ETIMEDOUT;
+                                goto fail;
+                        }
+
+                        left = timeout - n;
+                } else
+                        left = UINT64_MAX;
+
+                r = bus_poll(bus, true, left);
+                if (r < 0)
+                        goto fail;
+                if (r == 0) {
+                        r = -ETIMEDOUT;
+                        goto fail;
+                }
+
+                r = dispatch_wqueue(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                r = -ECONNRESET;
+                        }
+
+                        goto fail;
+                }
+        }
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_get_fd(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->input_fd == bus->output_fd, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSED)
+                return -ENOTCONN;
+
+        if (bus->inotify_fd >= 0)
+                return bus->inotify_fd;
+
+        if (bus->input_fd >= 0)
+                return bus->input_fd;
+
+        return -ENOTCONN;
+}
+
+_public_ int sd_bus_get_events(sd_bus *bus) {
+        int flags = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        switch (bus->state) {
+
+        case BUS_UNSET:
+        case BUS_CLOSED:
+                return -ENOTCONN;
+
+        case BUS_WATCH_BIND:
+                flags |= POLLIN;
+                break;
+
+        case BUS_OPENING:
+                flags |= POLLOUT;
+                break;
+
+        case BUS_AUTHENTICATING:
+                if (bus_socket_auth_needs_write(bus))
+                        flags |= POLLOUT;
+
+                flags |= POLLIN;
+                break;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                if (bus->rqueue_size <= 0)
+                        flags |= POLLIN;
+                if (bus->wqueue_size > 0)
+                        flags |= POLLOUT;
+                break;
+
+        case BUS_CLOSING:
+                break;
+
+        default:
+                assert_not_reached();
+        }
+
+        return flags;
+}
+
+_public_ int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
+        struct reply_callback *c;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state) && bus->state != BUS_CLOSING)
+                return -ENOTCONN;
+
+        if (bus->track_queue) {
+                *timeout_usec = 0;
+                return 1;
+        }
+
+        switch (bus->state) {
+
+        case BUS_AUTHENTICATING:
+                *timeout_usec = bus->auth_timeout;
+                return 1;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                if (bus->rqueue_size > 0) {
+                        *timeout_usec = 0;
+                        return 1;
+                }
+
+                c = prioq_peek(bus->reply_callbacks_prioq);
+                if (!c) {
+                        *timeout_usec = UINT64_MAX;
+                        return 0;
+                }
+
+                if (c->timeout_usec == 0) {
+                        *timeout_usec = UINT64_MAX;
+                        return 0;
+                }
+
+                *timeout_usec = c->timeout_usec;
+                return 1;
+
+        case BUS_CLOSING:
+                *timeout_usec = 0;
+                return 1;
+
+        case BUS_WATCH_BIND:
+        case BUS_OPENING:
+                *timeout_usec = UINT64_MAX;
+                return 0;
+
+        default:
+                assert_not_reached();
+        }
+}
+
+static int process_timeout(sd_bus *bus) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message* m = NULL;
+        struct reply_callback *c;
+        sd_bus_slot *slot;
+        bool is_hello;
+        usec_t n;
+        int r;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        c = prioq_peek(bus->reply_callbacks_prioq);
+        if (!c)
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout_usec > n)
+                return 0;
+
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->cookie,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Method call timed out"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        assert_se(prioq_pop(bus->reply_callbacks_prioq) == c);
+        c->timeout_usec = 0;
+
+        ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        bus->iteration_counter++;
+
+        is_hello = bus->state == BUS_HELLO && c->callback == hello_callback;
+
+        bus->current_message = m;
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+        bus->current_message = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        /* When this is the hello message and it timed out, then make sure to propagate the error up, don't just log
+         * and ignore the callback handler's return value. */
+        if (is_hello)
+                return r;
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_hello(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        if (bus->state != BUS_HELLO)
+                return 0;
+
+        /* Let's make sure the first message on the bus is the HELLO
+         * reply. But note that we don't actually parse the message
+         * here (we leave that to the usual handling), we just verify
+         * we don't let any earlier msg through. */
+
+        if (!IN_SET(m->header->type, SD_BUS_MESSAGE_METHOD_RETURN, SD_BUS_MESSAGE_METHOD_ERROR))
+                return -EIO;
+
+        if (m->reply_cookie != 1)
+                return -EIO;
+
+        return 0;
+}
+
+static int process_reply(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *synthetic_reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        struct reply_callback *c;
+        sd_bus_slot *slot;
+        bool is_hello;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (!IN_SET(m->header->type, SD_BUS_MESSAGE_METHOD_RETURN, SD_BUS_MESSAGE_METHOD_ERROR))
+                return 0;
+
+        if (m->destination && bus->unique_name && !streq_ptr(m->destination, bus->unique_name))
+                return 0;
+
+        c = ordered_hashmap_remove(bus->reply_callbacks, &m->reply_cookie);
+        if (!c)
+                return 0;
+
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        if (m->n_fds > 0 && !bus->accept_fd) {
+
+                /* If the reply contained a file descriptor which we
+                 * didn't want we pass an error instead. */
+
+                r = bus_message_new_synthetic_error(
+                                bus,
+                                m->reply_cookie,
+                                &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Reply message contained file descriptor"),
+                                &synthetic_reply);
+                if (r < 0)
+                        return r;
+
+                /* Copy over original timestamp */
+                synthetic_reply->realtime = m->realtime;
+                synthetic_reply->monotonic = m->monotonic;
+                synthetic_reply->seqnum = m->seqnum;
+                synthetic_reply->read_counter = m->read_counter;
+
+                r = bus_seal_synthetic_message(bus, synthetic_reply);
+                if (r < 0)
+                        return r;
+
+                m = synthetic_reply;
+        } else {
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+        }
+
+        if (c->timeout_usec != 0) {
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout_usec = 0;
+        }
+
+        is_hello = bus->state == BUS_HELLO && c->callback == hello_callback;
+
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        /* When this is the hello message and it failed, then make sure to propagate the error up, don't just log and
+         * ignore the callback handler's return value. */
+        if (is_hello)
+                return r;
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_filter(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->filter_callbacks_modified = false;
+
+                LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
+                        sd_bus_slot *slot;
+
+                        if (bus->filter_callbacks_modified)
+                                break;
+
+                        /* Don't run this more than once per iteration */
+                        if (l->last_iteration == bus->iteration_counter)
+                                continue;
+
+                        l->last_iteration = bus->iteration_counter;
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        slot = container_of(l, sd_bus_slot, filter_callback);
+
+                        bus->current_slot = sd_bus_slot_ref(slot);
+                        bus->current_handler = l->callback;
+                        bus->current_userdata = slot->userdata;
+                        r = l->callback(m, slot->userdata, &error_buffer);
+                        bus->current_userdata = NULL;
+                        bus->current_handler = NULL;
+                        bus->current_slot = sd_bus_slot_unref(slot);
+
+                        r = bus_maybe_reply_error(m, r, &error_buffer);
+                        if (r != 0)
+                                return r;
+
+                }
+
+        } while (bus->filter_callbacks_modified);
+
+        return 0;
+}
+
+static int process_match(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->match_callbacks_modified = false;
+
+                r = bus_match_run(bus, &bus->match_callbacks, m);
+                if (r != 0)
+                        return r;
+
+        } while (bus->match_callbacks_modified);
+
+        return 0;
+}
+
+static int process_builtin(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (bus->manual_peer_interface)
+                return 0;
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 0;
+
+        if (!streq_ptr(m->interface, "org.freedesktop.DBus.Peer"))
+                return 0;
+
+        if (m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 1;
+
+        if (streq_ptr(m->member, "Ping"))
+                r = sd_bus_message_new_method_return(m, &reply);
+        else if (streq_ptr(m->member, "GetMachineId")) {
+                sd_id128_t id;
+
+                r = sd_id128_get_machine(&id);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_new_method_return(m, &reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append(reply, "s", SD_ID128_TO_STRING(id));
+        } else {
+                r = sd_bus_message_new_method_errorf(
+                                m, &reply,
+                                SD_BUS_ERROR_UNKNOWN_METHOD,
+                                 "Unknown method '%s' on interface '%s'.", m->member, m->interface);
+        }
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int process_fd_check(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        /* If we got a message with a file descriptor which we didn't
+         * want to accept, then let's drop it. How can this even
+         * happen? For example, when the kernel queues a message into
+         * an activatable names's queue which allows fds, and then is
+         * delivered to us later even though we ourselves did not
+         * negotiate it. */
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (m->n_fds <= 0)
+                return 0;
+
+        if (bus->accept_fd)
+                return 0;
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 1; /* just eat it up */
+
+        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Message contains file descriptors, which I cannot accept. Sorry.");
+}
+
+static int process_message(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        bus->current_message = m;
+        bus->iteration_counter++;
+
+        log_debug_bus_message(m);
+
+        r = process_hello(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_reply(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_fd_check(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_builtin(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = bus_process_object(bus, m);
+
+finish:
+        bus->current_message = NULL;
+        return r;
+}
+
+static int dispatch_track(sd_bus *bus) {
+        assert(bus);
+
+        if (!bus->track_queue)
+                return 0;
+
+        bus_track_dispatch(bus->track_queue);
+        return 1;
+}
+
+static int process_running(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        r = process_timeout(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_wqueue(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_track(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_rqueue(bus, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        r = process_message(bus, m);
+        if (r != 0)
+                goto null_message;
+
+        if (ret) {
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                *ret = TAKE_PTR(m);
+                return 1;
+        }
+
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) {
+
+                log_debug("Unprocessed message call sender=%s object=%s interface=%s member=%s",
+                          strna(sd_bus_message_get_sender(m)),
+                          strna(sd_bus_message_get_path(m)),
+                          strna(sd_bus_message_get_interface(m)),
+                          strna(sd_bus_message_get_member(m)));
+
+                r = sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_UNKNOWN_OBJECT,
+                                "Unknown object '%s'.", m->path);
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+static int bus_exit_now(sd_bus *bus) {
+        assert(bus);
+
+        /* Exit due to close, if this is requested. If this is bus object is attached to an event source, invokes
+         * sd_event_exit(), otherwise invokes libc exit(). */
+
+        if (bus->exited) /* did we already exit? */
+                return 0;
+        if (!bus->exit_triggered) /* was the exit condition triggered? */
+                return 0;
+        if (!bus->exit_on_disconnect) /* Shall we actually exit on disconnection? */
+                return 0;
+
+        bus->exited = true; /* never exit more than once */
+
+        log_debug("Bus connection disconnected, exiting.");
+
+        if (bus->event)
+                return sd_event_exit(bus->event, EXIT_FAILURE);
+        else
+                exit(EXIT_FAILURE);
+
+        assert_not_reached();
+}
+
+static int process_closing_reply_callback(sd_bus *bus, struct reply_callback *c) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        sd_bus_slot *slot;
+        int r;
+
+        assert(bus);
+        assert(c);
+
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->cookie,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Connection terminated"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        if (c->timeout_usec != 0) {
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout_usec = 0;
+        }
+
+        ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        bus->iteration_counter++;
+
+        bus->current_message = m;
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+        bus->current_message = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_closing(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct reply_callback *c;
+        int r;
+
+        assert(bus);
+        assert(bus->state == BUS_CLOSING);
+
+        /* First, fail all outstanding method calls */
+        c = ordered_hashmap_first(bus->reply_callbacks);
+        if (c)
+                return process_closing_reply_callback(bus, c);
+
+        /* Then, fake-drop all remaining bus tracking references */
+        if (bus->tracks) {
+                bus_track_close(bus->tracks);
+                return 1;
+        }
+
+        /* Then, synthesize a Disconnected message */
+        r = sd_bus_message_new_signal(
+                        bus,
+                        &m,
+                        "/org/freedesktop/DBus/Local",
+                        "org.freedesktop.DBus.Local",
+                        "Disconnected");
+        if (r < 0)
+                return r;
+
+        bus_message_set_sender_local(bus, m);
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        sd_bus_close(bus);
+
+        bus->current_message = m;
+        bus->iteration_counter++;
+
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
+
+        /* Nothing else to do, exit now, if the condition holds */
+        bus->exit_triggered = true;
+        (void) bus_exit_now(bus);
+
+        if (ret)
+                *ret = TAKE_PTR(m);
+
+        r = 1;
+
+finish:
+        bus->current_message = NULL;
+
+        return r;
+}
+
+static int bus_process_internal(sd_bus *bus, sd_bus_message **ret) {
+        int r;
+
+        /* Returns 0 when we didn't do anything. This should cause the
+         * caller to invoke sd_bus_wait() before returning the next
+         * time. Returns > 0 when we did something, which possibly
+         * means *ret is filled in with an unprocessed message. */
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        /* We don't allow recursively invoking sd_bus_process(). */
+        assert_return(!bus->current_message, -EBUSY);
+        assert(!bus->current_slot); /* This should be NULL whenever bus->current_message is */
+
+        BUS_DONT_DESTROY(bus);
+
+        switch (bus->state) {
+
+        case BUS_UNSET:
+                return -ENOTCONN;
+
+        case BUS_CLOSED:
+                return -ECONNRESET;
+
+        case BUS_WATCH_BIND:
+                r = bus_socket_process_watch_bind(bus);
+                break;
+
+        case BUS_OPENING:
+                r = bus_socket_process_opening(bus);
+                break;
+
+        case BUS_AUTHENTICATING:
+                r = bus_socket_process_authenticating(bus);
+                break;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                r = process_running(bus, ret);
+                if (r >= 0)
+                        return r;
+
+                /* This branch initializes *ret, hence we don't use the generic error checking below */
+                break;
+
+        case BUS_CLOSING:
+                return process_closing(bus, ret);
+
+        default:
+                assert_not_reached();
+        }
+
+        if (r < 0) {
+                if (ERRNO_IS_DISCONNECT(r)) {
+                        bus_enter_closing(bus);
+                        r = 1;
+                } else
+                        return r;
+        }
+
+        if (ret)
+                *ret = NULL;
+
+        return r;
+}
+
+_public_ int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
+        return bus_process_internal(bus, ret);
+}
+
+_public_ int sd_bus_process_priority(sd_bus *bus, int64_t priority, sd_bus_message **ret) {
+        return bus_process_internal(bus, ret);
+}
+
+static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
+        struct pollfd p[2] = {};
+        usec_t m = USEC_INFINITY;
+        int r, n;
+
+        assert(bus);
+
+        if (bus->state == BUS_CLOSING)
+                return 1;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (bus->state == BUS_WATCH_BIND) {
+                assert(bus->inotify_fd >= 0);
+
+                p[0].events = POLLIN;
+                p[0].fd = bus->inotify_fd;
+                n = 1;
+        } else {
+                int e;
+
+                e = sd_bus_get_events(bus);
+                if (e < 0)
+                        return e;
+
+                if (need_more)
+                        /* The caller really needs some more data, they don't
+                         * care about what's already read, or any timeouts
+                         * except its own. */
+                        e |= POLLIN;
+                else {
+                        usec_t until;
+                        /* The caller wants to process if there's something to
+                         * process, but doesn't care otherwise */
+
+                        r = sd_bus_get_timeout(bus, &until);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                m = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+                }
+
+                p[0].fd = bus->input_fd;
+                if (bus->output_fd == bus->input_fd) {
+                        p[0].events = e;
+                        n = 1;
+                } else {
+                        p[0].events = e & POLLIN;
+                        p[1].fd = bus->output_fd;
+                        p[1].events = e & POLLOUT;
+                        n = 2;
+                }
+        }
+
+        if (timeout_usec != UINT64_MAX && (m == USEC_INFINITY || timeout_usec < m))
+                m = timeout_usec;
+
+        r = ppoll_usec(p, n, m);
+        if (r <= 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (bus->rqueue_size > 0)
+                return 0;
+
+        return bus_poll(bus, false, timeout_usec);
+}
+
+_public_ int sd_bus_flush(sd_bus *bus) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* We never were connected? Don't hang in inotify for good, as there's no timeout set for it */
+        if (bus->state == BUS_WATCH_BIND)
+                return -EUNATCH;
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        if (bus->wqueue_size <= 0)
+                return 0;
+
+        for (;;) {
+                r = dispatch_wqueue(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                return -ECONNRESET;
+                        }
+
+                        return r;
+                }
+
+                if (bus->wqueue_size <= 0)
+                        return 0;
+
+                r = bus_poll(bus, false, UINT64_MAX);
+                if (r < 0)
+                        return r;
+        }
+}
+
+_public_ int sd_bus_add_filter(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        sd_bus_slot *s;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        s = bus_slot_allocate(bus, !slot, BUS_FILTER_CALLBACK, sizeof(struct filter_callback), userdata);
+        if (!s)
+                return -ENOMEM;
+
+        s->filter_callback.callback = callback;
+
+        bus->filter_callbacks_modified = true;
+        LIST_PREPEND(callbacks, bus->filter_callbacks, &s->filter_callback);
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+}
+
+static int add_match_callback(
+                sd_bus_message *m,
+                void *userdata,
+                sd_bus_error *ret_error) {
+
+        sd_bus_slot *match_slot = ASSERT_PTR(userdata);
+        bool failed = false;
+        int r;
+
+        assert(m);
+
+        sd_bus_slot_ref(match_slot);
+
+        if (sd_bus_message_is_method_error(m, NULL)) {
+                log_debug_errno(sd_bus_message_get_errno(m),
+                                "Unable to add match %s, failing connection: %s",
+                                match_slot->match_callback.match_string,
+                                sd_bus_message_get_error(m)->message);
+
+                failed = true;
+        } else
+                log_debug("Match %s successfully installed.", match_slot->match_callback.match_string);
+
+        if (match_slot->match_callback.install_callback) {
+                sd_bus *bus;
+
+                bus = sd_bus_message_get_bus(m);
+
+                /* This function has been called as slot handler, and we want to call another slot handler. Let's
+                 * update the slot callback metadata temporarily with our own data, and then revert back to the old
+                 * values. */
+
+                assert(bus->current_slot == match_slot->match_callback.install_slot);
+                assert(bus->current_handler == add_match_callback);
+                assert(bus->current_userdata == userdata);
+
+                bus->current_slot = match_slot;
+                bus->current_handler = match_slot->match_callback.install_callback;
+                bus->current_userdata = match_slot->userdata;
+
+                r = match_slot->match_callback.install_callback(m, match_slot->userdata, ret_error);
+
+                bus->current_slot = match_slot->match_callback.install_slot;
+                bus->current_handler = add_match_callback;
+                bus->current_userdata = userdata;
+        } else {
+                if (failed) /* Generic failure handling: destroy the connection */
+                        bus_enter_closing(sd_bus_message_get_bus(m));
+
+                r = 1;
+        }
+
+        /* We don't need the install method reply slot anymore, let's free it */
+        match_slot->match_callback.install_slot = sd_bus_slot_unref(match_slot->match_callback.install_slot);
+
+        if (failed && match_slot->floating)
+                bus_slot_disconnect(match_slot, true);
+
+        sd_bus_slot_unref(match_slot);
+
+        return r;
+}
+
+static int bus_add_match_full(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                bool asynchronous,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                sd_bus_message_handler_t install_callback,
+                void *userdata) {
+
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+        sd_bus_slot *s = NULL;
+        int r = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(match, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_match_parse(match, &components, &n_components);
+        if (r < 0)
+                goto finish;
+
+        s = bus_slot_allocate(bus, !slot, BUS_MATCH_CALLBACK, sizeof(struct match_callback), userdata);
+        if (!s) {
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        s->match_callback.callback = callback;
+        s->match_callback.install_callback = install_callback;
+
+        if (bus->bus_client) {
+                enum bus_match_scope scope;
+
+                scope = bus_match_get_scope(components, n_components);
+
+                /* Do not install server-side matches for matches against the local service, interface or bus path. */
+                if (scope != BUS_MATCH_LOCAL) {
+
+                        /* We store the original match string, so that we can use it to remove the match again. */
+
+                        s->match_callback.match_string = strdup(match);
+                        if (!s->match_callback.match_string) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        if (asynchronous) {
+                                r = bus_add_match_internal_async(bus,
+                                                                 &s->match_callback.install_slot,
+                                                                 s->match_callback.match_string,
+                                                                 add_match_callback,
+                                                                 s);
+
+                                if (r < 0)
+                                        goto finish;
+
+                                /* Make the slot of the match call floating now. We need the reference, but we don't
+                                 * want that this match pins the bus object, hence we first create it non-floating, but
+                                 * then make it floating. */
+                                r = sd_bus_slot_set_floating(s->match_callback.install_slot, true);
+                        } else
+                                r = bus_add_match_internal(bus, s->match_callback.match_string, &s->match_callback.after);
+                        if (r < 0)
+                                goto finish;
+
+                        s->match_added = true;
+                }
+        }
+
+        bus->match_callbacks_modified = true;
+        r = bus_match_add(&bus->match_callbacks, components, n_components, &s->match_callback);
+        if (r < 0)
+                goto finish;
+
+        if (slot)
+                *slot = s;
+        s = NULL;
+
+finish:
+        bus_match_parse_free(components, n_components);
+        sd_bus_slot_unref(s);
+
+        return r;
+}
+
+_public_ int sd_bus_add_match(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        return bus_add_match_full(bus, slot, false, match, callback, NULL, userdata);
+}
+
+_public_ int sd_bus_add_match_async(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                sd_bus_message_handler_t install_callback,
+                void *userdata) {
+
+        return bus_add_match_full(bus, slot, true, match, callback, install_callback, userdata);
+}
+
+bool bus_pid_changed(sd_bus *bus) {
+        assert(bus);
+
+        /* We don't support people creating a bus connection and
+         * keeping it around over a fork(). Let's complain. */
+
+        return bus->original_pid != getpid_cached();
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_bus *bus = ASSERT_PTR(userdata);
+        int r;
+
+        /* Note that this is called both on input_fd, output_fd as well as inotify_fd events */
+
+        r = sd_bus_process(bus, NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Processing of bus failed, closing down: %m");
+                bus_enter_closing(bus);
+        }
+
+        return 1;
+}
+
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_bus *bus = ASSERT_PTR(userdata);
+        int r;
+
+        r = sd_bus_process(bus, NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Processing of bus failed, closing down: %m");
+                bus_enter_closing(bus);
+        }
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_bus *bus = ASSERT_PTR(userdata);
+        int r, e;
+        usec_t until;
+
+        assert(s);
+
+        e = sd_bus_get_events(bus);
+        if (e < 0) {
+                r = e;
+                goto fail;
+        }
+
+        if (bus->output_fd != bus->input_fd) {
+
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e & POLLIN);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_event_source_set_io_events(bus->output_io_event_source, e & POLLOUT);
+        } else
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_get_timeout(bus, &until);
+        if (r < 0)
+                goto fail;
+        if (r > 0) {
+                int j;
+
+                j = sd_event_source_set_time(bus->time_event_source, until);
+                if (j < 0) {
+                        r = j;
+                        goto fail;
+                }
+        }
+
+        r = sd_event_source_set_enabled(bus->time_event_source, r > 0 ? SD_EVENT_ONESHOT : SD_EVENT_OFF);
+        if (r < 0)
+                goto fail;
+
+        return 1;
+
+fail:
+        log_debug_errno(r, "Preparing of bus events failed, closing down: %m");
+        bus_enter_closing(bus);
+
+        return 1;
+}
+
+static int quit_callback(sd_event_source *event, void *userdata) {
+        sd_bus *bus = userdata;
+
+        assert(event);
+
+        if (bus->close_on_exit) {
+                sd_bus_flush(bus);
+                sd_bus_close(bus);
+        }
+
+        return 1;
+}
+
+int bus_attach_io_events(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->input_fd < 0)
+                return 0;
+
+        if (!bus->event)
+                return 0;
+
+        if (!bus->input_io_event_source) {
+                r = sd_event_add_io(bus->event, &bus->input_io_event_source, bus->input_fd, 0, io_callback, bus);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_prepare(bus->input_io_event_source, prepare_callback);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_priority(bus->input_io_event_source, bus->event_priority);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_description(bus->input_io_event_source, "bus-input");
+        } else
+                r = sd_event_source_set_io_fd(bus->input_io_event_source, bus->input_fd);
+
+        if (r < 0)
+                return r;
+
+        if (bus->output_fd != bus->input_fd) {
+                assert(bus->output_fd >= 0);
+
+                if (!bus->output_io_event_source) {
+                        r = sd_event_add_io(bus->event, &bus->output_io_event_source, bus->output_fd, 0, io_callback, bus);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_event_source_set_priority(bus->output_io_event_source, bus->event_priority);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_event_source_set_description(bus->input_io_event_source, "bus-output");
+                } else
+                        r = sd_event_source_set_io_fd(bus->output_io_event_source, bus->output_fd);
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static void bus_detach_io_events(sd_bus *bus) {
+        assert(bus);
+
+        bus->input_io_event_source = sd_event_source_disable_unref(bus->input_io_event_source);
+        bus->output_io_event_source = sd_event_source_disable_unref(bus->output_io_event_source);
+}
+
+int bus_attach_inotify_event(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->inotify_fd < 0)
+                return 0;
+
+        if (!bus->event)
+                return 0;
+
+        if (!bus->inotify_event_source) {
+                r = sd_event_add_io(bus->event, &bus->inotify_event_source, bus->inotify_fd, EPOLLIN, io_callback, bus);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_priority(bus->inotify_event_source, bus->event_priority);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_description(bus->inotify_event_source, "bus-inotify");
+        } else
+                r = sd_event_source_set_io_fd(bus->inotify_event_source, bus->inotify_fd);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+_public_ int sd_bus_attach_event(sd_bus *bus, sd_event *event, int priority) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus->event, -EBUSY);
+
+        assert(!bus->input_io_event_source);
+        assert(!bus->output_io_event_source);
+        assert(!bus->time_event_source);
+
+        if (event)
+                bus->event = sd_event_ref(event);
+        else  {
+                r = sd_event_default(&bus->event);
+                if (r < 0)
+                        return r;
+        }
+
+        bus->event_priority = priority;
+
+        r = sd_event_add_time(bus->event, &bus->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(bus->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(bus->time_event_source, "bus-time");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_exit(bus->event, &bus->quit_event_source, quit_callback, bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(bus->quit_event_source, "bus-exit");
+        if (r < 0)
+                goto fail;
+
+        r = bus_attach_io_events(bus);
+        if (r < 0)
+                goto fail;
+
+        r = bus_attach_inotify_event(bus);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_bus_detach_event(bus);
+        return r;
+}
+
+_public_ int sd_bus_detach_event(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        if (!bus->event)
+                return 0;
+
+        bus_detach_io_events(bus);
+        bus->inotify_event_source = sd_event_source_disable_unref(bus->inotify_event_source);
+        bus->time_event_source = sd_event_source_disable_unref(bus->time_event_source);
+        bus->quit_event_source = sd_event_source_disable_unref(bus->quit_event_source);
+
+        bus->event = sd_event_unref(bus->event);
+        return 1;
+}
+
+_public_ sd_event* sd_bus_get_event(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->event;
+}
+
+_public_ sd_bus_message* sd_bus_get_current_message(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_message;
+}
+
+_public_ sd_bus_slot* sd_bus_get_current_slot(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_slot;
+}
+
+_public_ sd_bus_message_handler_t sd_bus_get_current_handler(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_handler;
+}
+
+_public_ void* sd_bus_get_current_userdata(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_userdata;
+}
+
+static int bus_default(int (*bus_open)(sd_bus **), sd_bus **default_bus, sd_bus **ret) {
+        sd_bus *b = NULL;
+        int r;
+
+        assert(bus_open);
+        assert(default_bus);
+
+        if (!ret)
+                return !!*default_bus;
+
+        if (*default_bus) {
+                *ret = sd_bus_ref(*default_bus);
+                return 0;
+        }
+
+        r = bus_open(&b);
+        if (r < 0)
+                return r;
+
+        b->default_bus_ptr = default_bus;
+        b->tid = gettid();
+        *default_bus = b;
+
+        *ret = b;
+        return 1;
+}
+
+_public_ int sd_bus_default_system(sd_bus **ret) {
+        return bus_default(sd_bus_open_system, &default_system_bus, ret);
+}
+
+_public_ int sd_bus_default_user(sd_bus **ret) {
+        return bus_default(sd_bus_open_user, &default_user_bus, ret);
+}
+
+_public_ int sd_bus_default(sd_bus **ret) {
+        int (*bus_open)(sd_bus **) = NULL;
+        sd_bus **busp;
+
+        busp = bus_choose_default(&bus_open);
+        return bus_default(bus_open, busp, ret);
+}
+
+_public_ int sd_bus_get_tid(sd_bus *b, pid_t *tid) {
+        assert_return(b, -EINVAL);
+        assert_return(tid, -EINVAL);
+        assert_return(!bus_pid_changed(b), -ECHILD);
+
+        if (b->tid != 0) {
+                *tid = b->tid;
+                return 0;
+        }
+
+        if (b->event)
+                return sd_event_get_tid(b->event, tid);
+
+        return -ENXIO;
+}
+
+_public_ int sd_bus_path_encode(const char *prefix, const char *external_id, char **ret_path) {
+        _cleanup_free_ char *e = NULL;
+        char *ret;
+
+        assert_return(object_path_is_valid(prefix), -EINVAL);
+        assert_return(external_id, -EINVAL);
+        assert_return(ret_path, -EINVAL);
+
+        e = bus_label_escape(external_id);
+        if (!e)
+                return -ENOMEM;
+
+        ret = path_join(prefix, e);
+        if (!ret)
+                return -ENOMEM;
+
+        *ret_path = ret;
+        return 0;
+}
+
+_public_ int sd_bus_path_decode(const char *path, const char *prefix, char **external_id) {
+        const char *e;
+        char *ret;
+
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(object_path_is_valid(prefix), -EINVAL);
+        assert_return(external_id, -EINVAL);
+
+        e = object_path_startswith(path, prefix);
+        if (!e) {
+                *external_id = NULL;
+                return 0;
+        }
+
+        /* Note that 'e' might be an empty string here. That's expected. E.g. a case where the subtree
+         * corresponds to a subtree on a disk, and we want to return something that represents the root
+         * of the filesystem. */
+
+        ret = bus_label_unescape(e);
+        if (!ret)
+                return -ENOMEM;
+
+        *external_id = ret;
+        return 1;
+}
+
+_public_ int sd_bus_path_encode_many(char **out, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        char *path, *path_pos, **label_pos;
+        const char *sep, *template_pos;
+        size_t path_length;
+        va_list list;
+        int r;
+
+        assert_return(out, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_length = strlen(path_template);
+
+        va_start(list, path_template);
+        for (sep = strchr(path_template, '%'); sep; sep = strchr(sep + 1, '%')) {
+                const char *arg;
+                char *label;
+
+                arg = va_arg(list, const char *);
+                if (!arg) {
+                        va_end(list);
+                        return -EINVAL;
+                }
+
+                label = bus_label_escape(arg);
+                if (!label) {
+                        va_end(list);
+                        return -ENOMEM;
+                }
+
+                r = strv_consume(&labels, label);
+                if (r < 0) {
+                        va_end(list);
+                        return r;
+                }
+
+                /* add label length, but account for the format character */
+                path_length += strlen(label) - 1;
+        }
+        va_end(list);
+
+        path = malloc(path_length + 1);
+        if (!path)
+                return -ENOMEM;
+
+        path_pos = path;
+        label_pos = labels;
+
+        for (template_pos = path_template; *template_pos; ) {
+                sep = strchrnul(template_pos, '%');
+                path_pos = mempcpy(path_pos, template_pos, sep - template_pos);
+                if (!*sep)
+                        break;
+
+                path_pos = stpcpy(path_pos, *label_pos++);
+                template_pos = sep + 1;
+        }
+
+        *path_pos = 0;
+        *out = path;
+        return 0;
+}
+
+_public_ int sd_bus_path_decode_many(const char *path, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        const char *template_pos, *path_pos;
+        char **label_pos;
+        va_list list;
+        int r;
+
+        /*
+         * This decodes an object-path based on a template argument. The
+         * template consists of a verbatim path, optionally including special
+         * directives:
+         *
+         *   - Each occurrence of '%' in the template matches an arbitrary
+         *     substring of a label in the given path. At most one such
+         *     directive is allowed per label. For each such directive, the
+         *     caller must provide an output parameter (char **) via va_arg. If
+         *     NULL is passed, the given label is verified, but not returned.
+         *     For each matched label, the *decoded* label is stored in the
+         *     passed output argument, and the caller is responsible to free
+         *     it. Note that the output arguments are only modified if the
+         *     actually path matched the template. Otherwise, they're left
+         *     untouched.
+         *
+         * This function returns <0 on error, 0 if the path does not match the
+         * template, 1 if it matched.
+         */
+
+        assert_return(path, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_pos = path;
+
+        for (template_pos = path_template; *template_pos; ) {
+                const char *sep;
+                size_t length;
+                char *label;
+
+                /* verify everything until the next '%' matches verbatim */
+                sep = strchrnul(template_pos, '%');
+                length = sep - template_pos;
+                if (strncmp(path_pos, template_pos, length))
+                        return 0;
+
+                path_pos += length;
+                template_pos += length;
+
+                if (!*template_pos)
+                        break;
+
+                /* We found the next '%' character. Everything up until here
+                 * matched. We now skip ahead to the end of this label and make
+                 * sure it matches the tail of the label in the path. Then we
+                 * decode the string in-between and save it for later use. */
+
+                ++template_pos; /* skip over '%' */
+
+                sep = strchrnul(template_pos, '/');
+                length = sep - template_pos; /* length of suffix to match verbatim */
+
+                /* verify the suffixes match */
+                sep = strchrnul(path_pos, '/');
+                if (sep - path_pos < (ssize_t)length ||
+                    strncmp(sep - length, template_pos, length))
+                        return 0;
+
+                template_pos += length; /* skip over matched label */
+                length = sep - path_pos - length; /* length of sub-label to decode */
+
+                /* store unescaped label for later use */
+                label = bus_label_unescape_n(path_pos, length);
+                if (!label)
+                        return -ENOMEM;
+
+                r = strv_consume(&labels, label);
+                if (r < 0)
+                        return r;
+
+                path_pos = sep; /* skip decoded label and suffix */
+        }
+
+        /* end of template must match end of path */
+        if (*path_pos)
+                return 0;
+
+        /* copy the labels over to the caller */
+        va_start(list, path_template);
+        for (label_pos = labels; label_pos && *label_pos; ++label_pos) {
+                char **arg;
+
+                arg = va_arg(list, char **);
+                if (arg)
+                        *arg = *label_pos;
+                else
+                        free(*label_pos);
+        }
+        va_end(list);
+
+        labels = mfree(labels);
+        return 1;
+}
+
+_public_ int sd_bus_try_close(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return -EOPNOTSUPP;
+}
+
+_public_ int sd_bus_get_description(sd_bus *bus, const char **description) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(description, -EINVAL);
+
+        if (bus->description)
+                *description = bus->description;
+        else if (bus->is_system)
+                *description = "system";
+        else if (bus->is_user)
+                *description = "user";
+        else
+                return -ENXIO;
+
+        return 0;
+}
+
+_public_ int sd_bus_get_scope(sd_bus *bus, const char **scope) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(scope, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->is_user) {
+                *scope = "user";
+                return 0;
+        }
+
+        if (bus->is_system) {
+                *scope = "system";
+                return 0;
+        }
+
+        return -ENODATA;
+}
+
+_public_ int sd_bus_get_address(sd_bus *bus, const char **address) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(address, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->address) {
+                *address = bus->address;
+                return 0;
+        }
+
+        return -ENODATA;
+}
+
+_public_ int sd_bus_get_creds_mask(sd_bus *bus, uint64_t *mask) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(mask, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        *mask = bus->creds_mask;
+        return 0;
+}
+
+_public_ int sd_bus_is_bus_client(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->bus_client;
+}
+
+_public_ int sd_bus_is_server(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->is_server;
+}
+
+_public_ int sd_bus_is_anonymous(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->anonymous_auth;
+}
+
+_public_ int sd_bus_is_trusted(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->trusted;
+}
+
+_public_ int sd_bus_is_monitor(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->is_monitor;
+}
+
+static void flush_close(sd_bus *bus) {
+        if (!bus)
+                return;
+
+        /* Flushes and closes the specified bus. We take a ref before,
+         * to ensure the flushing does not cause the bus to be
+         * unreferenced. */
+
+        sd_bus_flush_close_unref(sd_bus_ref(bus));
+}
+
+_public_ void sd_bus_default_flush_close(void) {
+        flush_close(default_starter_bus);
+        flush_close(default_user_bus);
+        flush_close(default_system_bus);
+}
+
+_public_ int sd_bus_set_exit_on_disconnect(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        /* Turns on exit-on-disconnect, and triggers it immediately if the bus connection was already
+         * disconnected. Note that this is triggered exclusively on disconnections triggered by the server side, never
+         * from the client side. */
+        bus->exit_on_disconnect = b;
+
+        /* If the exit condition was triggered already, exit immediately. */
+        return bus_exit_now(bus);
+}
+
+_public_ int sd_bus_get_exit_on_disconnect(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        return bus->exit_on_disconnect;
+}
+
+_public_ int sd_bus_set_sender(sd_bus *bus, const char *sender) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus->bus_client, -EPERM);
+        assert_return(!sender || service_name_is_valid(sender), -EINVAL);
+
+        return free_and_strdup(&bus->patch_sender, sender);
+}
+
+_public_ int sd_bus_get_sender(sd_bus *bus, const char **ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(ret, -EINVAL);
+
+        if (!bus->patch_sender)
+                return -ENODATA;
+
+        *ret = bus->patch_sender;
+        return 0;
+}
+
+_public_ int sd_bus_get_n_queued_read(sd_bus *bus, uint64_t *ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(ret, -EINVAL);
+
+        *ret = bus->rqueue_size;
+        return 0;
+}
+
+_public_ int sd_bus_get_n_queued_write(sd_bus *bus, uint64_t *ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(ret, -EINVAL);
+
+        *ret = bus->wqueue_size;
+        return 0;
+}
+
+_public_ int sd_bus_set_method_call_timeout(sd_bus *bus, uint64_t usec) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        bus->method_call_timeout = usec;
+        return 0;
+}
+
+_public_ int sd_bus_get_method_call_timeout(sd_bus *bus, uint64_t *ret) {
+        const char *e;
+        usec_t usec;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(ret, -EINVAL);
+
+        if (bus->method_call_timeout != 0) {
+                *ret = bus->method_call_timeout;
+                return 0;
+        }
+
+        e = secure_getenv("SYSTEMD_BUS_TIMEOUT");
+        if (e && parse_sec(e, &usec) >= 0 && usec != 0) {
+                /* Save the parsed value to avoid multiple parsing. To change the timeout value,
+                 * use sd_bus_set_method_call_timeout() instead of setenv(). */
+                *ret = bus->method_call_timeout = usec;
+                return 0;
+        }
+
+        *ret = bus->method_call_timeout = BUS_DEFAULT_TIMEOUT;
+        return 0;
+}
+
+_public_ int sd_bus_set_close_on_exit(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        bus->close_on_exit = b;
+        return 0;
+}
+
+_public_ int sd_bus_get_close_on_exit(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        return bus->close_on_exit;
+}
+
+_public_ int sd_bus_enqueue_for_read(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* Re-enqueue a message for reading. This is primarily useful for PolicyKit-style authentication,
+         * where we accept a message, then determine we need to interactively authenticate the user, and then
+         * we want to process the message again. */
+
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        bus->rqueue[bus->rqueue_size++] = bus_message_ref_queued(m, bus);
+        return 0;
+}