chiark / gitweb /
bus: properly handle if we get disconnected during HELLO phase
[elogind.git] / src / libsystemd-bus / sd-bus.c
index 3bdbd111325ae8081ffff7e6afb1f6db2639edec..f13e346dcfb105f0830e60e957b94e838b467bde 100644 (file)
 #include <netdb.h>
 #include <sys/poll.h>
 #include <byteswap.h>
+#include <sys/mman.h>
+#include <pthread.h>
 
 #include "util.h"
 #include "macro.h"
-#include "missing.h"
 #include "strv.h"
+#include "set.h"
+#include "missing.h"
 
 #include "sd-bus.h"
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-type.h"
+#include "bus-socket.h"
+#include "bus-kernel.h"
+#include "bus-control.h"
+#include "bus-introspect.h"
+#include "bus-signature.h"
+#include "bus-objects.h"
+#include "bus-util.h"
+#include "bus-container.h"
 
 static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec);
 
+static void bus_close_fds(sd_bus *b) {
+        assert(b);
+
+        if (b->input_fd >= 0)
+                close_nointr_nofail(b->input_fd);
+
+        if (b->output_fd >= 0 && b->output_fd != b->input_fd)
+                close_nointr_nofail(b->output_fd);
+
+        b->input_fd = b->output_fd = -1;
+}
+
+static void bus_node_destroy(sd_bus *b, struct node *n) {
+        struct node_callback *c;
+        struct node_vtable *v;
+        struct node_enumerator *e;
+
+        assert(b);
+
+        if (!n)
+                return;
+
+        while (n->child)
+                bus_node_destroy(b, n->child);
+
+        while ((c = n->callbacks)) {
+                LIST_REMOVE(callbacks, n->callbacks, c);
+                free(c);
+        }
+
+        while ((v = n->vtables)) {
+                LIST_REMOVE(vtables, n->vtables, v);
+                free(v->interface);
+                free(v);
+        }
+
+        while ((e = n->enumerators)) {
+                LIST_REMOVE(enumerators, n->enumerators, e);
+                free(e);
+        }
+
+        if (n->parent)
+                LIST_REMOVE(siblings, n->parent->child, n);
+
+        assert_se(hashmap_remove(b->nodes, n->path) == n);
+        free(n->path);
+        free(n);
+}
+
+static void bus_reset_queues(sd_bus *b) {
+        unsigned i;
+
+        assert(b);
+
+        for (i = 0; i < b->rqueue_size; i++)
+                sd_bus_message_unref(b->rqueue[i]);
+        free(b->rqueue);
+
+        for (i = 0; i < b->wqueue_size; i++)
+                sd_bus_message_unref(b->wqueue[i]);
+        free(b->wqueue);
+
+        b->rqueue = b->wqueue = NULL;
+        b->rqueue_size = b->wqueue_size = 0;
+}
+
 static void bus_free(sd_bus *b) {
         struct filter_callback *f;
-        struct object_callback *c;
-        unsigned i;
+        struct node *n;
 
         assert(b);
 
-        if (b->fd >= 0)
-                close_nointr_nofail(b->fd);
+        sd_bus_detach_event(b);
+
+        bus_close_fds(b);
+
+        if (b->kdbus_buffer)
+                munmap(b->kdbus_buffer, KDBUS_POOL_SIZE);
 
         free(b->rbuffer);
         free(b->unique_name);
-        free(b->auth_uid);
+        free(b->auth_buffer);
         free(b->address);
+        free(b->kernel);
+        free(b->machine);
 
         free(b->exec_path);
         strv_free(b->exec_argv);
@@ -60,46 +142,49 @@ static void bus_free(sd_bus *b) {
         close_many(b->fds, b->n_fds);
         free(b->fds);
 
-        for (i = 0; i < b->rqueue_size; i++)
-                sd_bus_message_unref(b->rqueue[i]);
-        free(b->rqueue);
-
-        for (i = 0; i < b->wqueue_size; i++)
-                sd_bus_message_unref(b->wqueue[i]);
-        free(b->wqueue);
+        bus_reset_queues(b);
 
         hashmap_free_free(b->reply_callbacks);
         prioq_free(b->reply_callbacks_prioq);
 
         while ((f = b->filter_callbacks)) {
-                LIST_REMOVE(struct filter_callback, callbacks, b->filter_callbacks, f);
+                LIST_REMOVE(callbacks, b->filter_callbacks, f);
                 free(f);
         }
 
-        while ((c = hashmap_steal_first(b->object_callbacks))) {
-                free(c->path);
-                free(c);
-        }
+        bus_match_free(&b->match_callbacks);
+
+        hashmap_free_free(b->vtable_methods);
+        hashmap_free_free(b->vtable_properties);
+
+        while ((n = hashmap_first(b->nodes)))
+                bus_node_destroy(b, n);
 
-        hashmap_free(b->object_callbacks);
+        hashmap_free(b->nodes);
+
+        bus_kernel_flush_memfd(b);
+
+        assert_se(pthread_mutex_destroy(&b->memfd_cache_mutex) == 0);
 
         free(b);
 }
 
-int sd_bus_new(sd_bus **ret) {
+_public_ int sd_bus_new(sd_bus **ret) {
         sd_bus *r;
 
-        if (!ret)
-                return -EINVAL;
+        assert_return(ret, -EINVAL);
 
         r = new0(sd_bus, 1);
         if (!r)
                 return -ENOMEM;
 
-        r->n_ref = 1;
-        r->fd = -1;
+        r->n_ref = REFCNT_INIT;
+        r->input_fd = r->output_fd = -1;
         r->message_version = 1;
-        r->negotiate_fds = true;
+        r->hello_flags |= KDBUS_HELLO_ACCEPT_FD;
+        r->original_pid = getpid();
+
+        assert_se(pthread_mutex_init(&r->memfd_cache_mutex, NULL) == 0);
 
         /* We guarantee that wqueue always has space for at least one
          * entry */
@@ -113,15 +198,13 @@ int sd_bus_new(sd_bus **ret) {
         return 0;
 }
 
-int sd_bus_set_address(sd_bus *bus, const char *address) {
+_public_ int sd_bus_set_address(sd_bus *bus, const char *address) {
         char *a;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
-        if (!address)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(address, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         a = strdup(address);
         if (!a)
@@ -133,29 +216,26 @@ int sd_bus_set_address(sd_bus *bus, const char *address) {
         return 0;
 }
 
-int sd_bus_set_fd(sd_bus *bus, int fd) {
-        if (!bus)
-                return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
-        if (fd < 0)
-                return -EINVAL;
+_public_ int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(input_fd >= 0, -EINVAL);
+        assert_return(output_fd >= 0, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-        bus->fd = fd;
+        bus->input_fd = input_fd;
+        bus->output_fd = output_fd;
         return 0;
 }
 
-int sd_bus_set_exec(sd_bus *bus, const char *path, char *const argv[]) {
+_public_ int sd_bus_set_exec(sd_bus *bus, const char *path, char *const argv[]) {
         char *p, **a;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
-        if (!path)
-                return -EINVAL;
-        if (strv_isempty(argv))
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(path, -EINVAL);
+        assert_return(!strv_isempty(argv), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         p = strdup(path);
         if (!p)
@@ -176,38 +256,139 @@ int sd_bus_set_exec(sd_bus *bus, const char *path, char *const argv[]) {
         return 0;
 }
 
-int sd_bus_set_hello(sd_bus *bus, int b) {
-        if (!bus)
-                return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
+_public_ int sd_bus_set_bus_client(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-        bus->send_hello = !!b;
+        bus->bus_client = !!b;
         return 0;
 }
 
-int sd_bus_set_negotiate_fds(sd_bus *bus, int b) {
-        if (!bus)
-                return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
+_public_ int sd_bus_negotiate_fds(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ACCEPT_FD, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_timestamp(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_TIMESTAMP, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_creds(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_CREDS, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_comm(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_COMM, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_exe(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_EXE, b);
+        return 0;
+}
 
-        bus->negotiate_fds = !!b;
+_public_ int sd_bus_negotiate_attach_cmdline(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_CMDLINE, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_cgroup(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_CGROUP, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_caps(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_CAPS, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_selinux_context(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_SECLABEL, b);
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_attach_audit(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->hello_flags, KDBUS_HELLO_ATTACH_AUDIT, b);
+        return 0;
+}
+
+_public_ int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
+        assert_return(bus, -EINVAL);
+        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->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->anonymous_auth = !!b;
         return 0;
 }
 
-static int hello_callback(sd_bus *bus, int error, sd_bus_message *reply, void *userdata) {
+static int hello_callback(sd_bus *bus, sd_bus_message *reply, void *userdata, sd_bus_error *error) {
         const char *s;
         int r;
 
         assert(bus);
-        assert(bus->state == BUS_HELLO);
-
-        if (error != 0)
-                return -error;
-
+        assert(bus->state == BUS_HELLO || bus->state == BUS_CLOSING);
         assert(reply);
 
+        r = sd_bus_message_get_errno(reply);
+        if (r < 0)
+                return r;
+        if (r > 0)
+                return -r;
+
         r = sd_bus_message_read(reply, "s", &s);
         if (r < 0)
                 return r;
@@ -219,7 +400,8 @@ static int hello_callback(sd_bus *bus, int error, sd_bus_message *reply, void *u
         if (!bus->unique_name)
                 return -ENOMEM;
 
-        bus->state = BUS_RUNNING;
+        if (bus->state == BUS_HELLO)
+                bus->state = BUS_RUNNING;
 
         return 1;
 }
@@ -230,7 +412,7 @@ static int bus_send_hello(sd_bus *bus) {
 
         assert(bus);
 
-        if (!bus->send_hello)
+        if (!bus->bus_client || bus->is_kernel)
                 return 0;
 
         r = sd_bus_message_new_method_call(
@@ -243,17 +425,13 @@ static int bus_send_hello(sd_bus *bus) {
         if (r < 0)
                 return r;
 
-        r = sd_bus_send_with_reply(bus, m, hello_callback, NULL, 0, NULL);
-        if (r < 0)
-                return r;
-
-        return r;
+        return sd_bus_call_async(bus, m, hello_callback, NULL, 0, &bus->hello_serial);
 }
 
-static int bus_start_running(sd_bus *bus) {
+int bus_start_running(sd_bus *bus) {
         assert(bus);
 
-        if (bus->send_hello) {
+        if (bus->bus_client && !bus->is_kernel) {
                 bus->state = BUS_HELLO;
                 return 1;
         }
@@ -411,8 +589,11 @@ static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
 
 static int parse_tcp_address(sd_bus *b, const char **p, char **guid) {
         _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
-        struct addrinfo hints, *result;
         int r;
+        struct addrinfo *result, hints = {
+                .ai_socktype = SOCK_STREAM,
+                .ai_flags = AI_ADDRCONFIG,
+        };
 
         assert(b);
         assert(p);
@@ -450,10 +631,6 @@ static int parse_tcp_address(sd_bus *b, const char **p, char **guid) {
         if (!host || !port)
                 return -EINVAL;
 
-        zero(hints);
-        hints.ai_socktype = SOCK_STREAM;
-        hints.ai_flags = AI_ADDRCONFIG;
-
         if (family) {
                 if (streq(family, "ipv4"))
                         hints.ai_family = AF_INET;
@@ -506,7 +683,7 @@ static int parse_exec_address(sd_bus *b, const char **p, char **guid) {
 
                         errno = 0;
                         ul = strtoul(*p + 4, (char**) p, 10);
-                        if (errno != 0 || **p != '=' || ul > 256) {
+                        if (errno > 0 || **p != '=' || ul > 256) {
                                 r = -EINVAL;
                                 goto fail;
                         }
@@ -538,8 +715,10 @@ static int parse_exec_address(sd_bus *b, const char **p, char **guid) {
                 skip_address_key(p);
         }
 
-        if (!path)
+        if (!path) {
+                r = -EINVAL;
                 goto fail;
+        }
 
         /* Make sure there are no holes in the array, with the
          * exception of argv[0] */
@@ -570,6 +749,80 @@ fail:
         return r;
 }
 
+static int parse_kernel_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *path = NULL;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (**p != 0 && **p != ';') {
+                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;
+
+                skip_address_key(p);
+        }
+
+        if (!path)
+                return -EINVAL;
+
+        free(b->kernel);
+        b->kernel = path;
+        path = NULL;
+
+        return 0;
+}
+
+static int parse_container_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *machine = NULL;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (**p != 0 && **p != ';') {
+                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;
+
+                skip_address_key(p);
+        }
+
+        if (!machine)
+                return -EINVAL;
+
+        free(b->machine);
+        b->machine = machine;
+        machine = NULL;
+
+        b->sockaddr.un.sun_family = AF_UNIX;
+        strncpy(b->sockaddr.un.sun_path, "/var/run/dbus/system_bus_socket", sizeof(b->sockaddr.un.sun_path));
+        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + sizeof("/var/run/dbus/system_bus_socket") - 1;
+
+        return 0;
+}
+
 static void bus_reset_parsed_address(sd_bus *b) {
         assert(b);
 
@@ -579,7 +832,11 @@ static void bus_reset_parsed_address(sd_bus *b) {
         free(b->exec_path);
         b->exec_path = NULL;
         b->exec_argv = NULL;
-        b->peer = SD_ID128_NULL;
+        b->server_id = SD_ID128_NULL;
+        free(b->kernel);
+        b->kernel = NULL;
+        free(b->machine);
+        b->machine = NULL;
 }
 
 static int bus_parse_next_address(sd_bus *b) {
@@ -631,6 +888,22 @@ static int bus_parse_next_address(sd_bus *b) {
 
                         break;
 
+                } else if (startswith(a, "kernel:")) {
+
+                        a += 7;
+                        r = parse_kernel_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                } else if (startswith(a, "x-container:")) {
+
+                        a += 12;
+                        r = parse_container_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
                 }
 
                 a = strchr(a, ';');
@@ -639,7 +912,7 @@ static int bus_parse_next_address(sd_bus *b) {
         }
 
         if (guid) {
-                r = sd_id128_from_string(guid, &b->peer);
+                r = sd_id128_from_string(guid, &b->server_id);
                 if (r < 0)
                         return r;
         }
@@ -648,378 +921,112 @@ static int bus_parse_next_address(sd_bus *b) {
         return 1;
 }
 
-static void iovec_advance(struct iovec *iov, unsigned *idx, size_t size) {
+static int bus_start_address(sd_bus *b) {
+        int r;
 
-        while (size > 0) {
-                struct iovec *i = iov + *idx;
+        assert(b);
 
-                if (i->iov_len > size) {
-                        i->iov_base = (uint8_t*) i->iov_base + size;
-                        i->iov_len -= size;
-                        return;
-                }
+        for (;;) {
+                sd_bus_close(b);
 
-                size -= i->iov_len;
+                if (b->exec_path) {
 
-                i->iov_base = NULL;
-                i->iov_len = 0;
+                        r = bus_socket_exec(b);
+                        if (r >= 0)
+                                return r;
 
-                (*idx) ++;
-        }
-}
+                        b->last_connect_error = -r;
+                } else if (b->kernel) {
 
-static int bus_write_auth(sd_bus *b) {
-        struct msghdr mh;
-        ssize_t k;
+                        r = bus_kernel_connect(b);
+                        if (r >= 0)
+                                return r;
 
-        assert(b);
-        assert(b->state == BUS_AUTHENTICATING);
+                        b->last_connect_error = -r;
 
-        if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
-                return 0;
+                } else if (b->machine) {
 
-        if (b->auth_timeout == 0)
-                b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
+                        r = bus_container_connect(b);
+                        if (r >= 0)
+                                return r;
 
-        zero(mh);
-        mh.msg_iov = b->auth_iovec + b->auth_index;
-        mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
+                        b->last_connect_error = -r;
 
-        k = sendmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
+                } else if (b->sockaddr.sa.sa_family != AF_UNSPEC) {
 
-        iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
+                        r = bus_socket_connect(b);
+                        if (r >= 0)
+                                return r;
 
-        return 1;
+                        b->last_connect_error = -r;
+                }
+
+                r = bus_parse_next_address(b);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return b->last_connect_error ? -b->last_connect_error : -ECONNREFUSED;
+        }
 }
 
-static int bus_auth_verify(sd_bus *b) {
-        char *e, *f, *start;
-        sd_id128_t peer;
-        unsigned i;
+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;
 
-        /* We expect two response lines: "OK" and possibly
-         * "AGREE_UNIX_FD" */
+        assert(b);
+        assert(b->input_fd >= 0);
+        assert(b->output_fd >= 0);
 
-        e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2);
-        if (!e)
-                return 0;
+        r = fd_nonblock(b->input_fd, true);
+        if (r < 0)
+                return r;
 
-        if (b->negotiate_fds) {
-                f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
-                if (!f)
-                        return 0;
+        r = fd_cloexec(b->input_fd, true);
+        if (r < 0)
+                return r;
 
-                start = f + 2;
-        } else {
-                f = NULL;
-                start = e + 2;
+        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;
         }
 
-        /* Nice! We got all the lines we need. First check the OK
-         * line */
+        if (fstat(b->input_fd, &st) < 0)
+                return -errno;
 
-        if (e - (char*) b->rbuffer != 3 + 32)
-                return -EPERM;
-
-        if (memcmp(b->rbuffer, "OK ", 3))
-                return -EPERM;
-
-        for (i = 0; i < 32; i += 2) {
-                int x, y;
-
-                x = unhexchar(((char*) b->rbuffer)[3 + i]);
-                y = unhexchar(((char*) b->rbuffer)[3 + i + 1]);
-
-                if (x < 0 || y < 0)
-                        return -EINVAL;
-
-                peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
-        }
-
-        if (!sd_id128_equal(b->peer, SD_ID128_NULL) &&
-            !sd_id128_equal(b->peer, peer))
-                return -EPERM;
-
-        b->peer = peer;
-
-        /* And possibly check the second line, too */
-
-        if (f)
-                b->can_fds =
-                        (f - e == sizeof("\r\nAGREE_UNIX_FD") - 1) &&
-                        memcmp(e + 2, "AGREE_UNIX_FD", sizeof("AGREE_UNIX_FD") - 1) == 0;
-
-        b->rbuffer_size -= (start - (char*) b->rbuffer);
-        memmove(b->rbuffer, start, b->rbuffer_size);
-
-        r = bus_start_running(b);
-        if (r < 0)
-                return r;
-
-        return 1;
-}
-
-static int bus_read_auth(sd_bus *b) {
-        struct msghdr mh;
-        struct iovec iov;
-        size_t n;
-        ssize_t k;
-        int r;
-        void *p;
-
-        assert(b);
-
-        r = bus_auth_verify(b);
-        if (r != 0)
-                return r;
-
-        n = MAX(3 + 32 + 2 + sizeof("AGREE_UNIX_FD") - 1 + 2, b->rbuffer_size * 2);
-
-        if (n > BUS_AUTH_SIZE_MAX)
-                n = BUS_AUTH_SIZE_MAX;
-
-        if (b->rbuffer_size >= n)
-                return -ENOBUFS;
-
-        p = realloc(b->rbuffer, n);
-        if (!p)
-                return -ENOMEM;
-
-        b->rbuffer = p;
-
-        zero(iov);
-        iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
-        iov.iov_len = n - b->rbuffer_size;
-
-        zero(mh);
-        mh.msg_iov = &iov;
-        mh.msg_iovlen = 1;
-
-        k = recvmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
-        if (k == 0)
-                return -ECONNRESET;
-
-        b->rbuffer_size += k;
-
-        r = bus_auth_verify(b);
-        if (r != 0)
-                return r;
-
-        return 1;
-}
-
-static int bus_setup_fd(sd_bus *b) {
-        int one;
-
-        assert(b);
-
-        /* Enable SO_PASSCRED + SO_PASSEC. We try this on any socket,
-         * just in case. This is actually irrelavant for */
-        one = 1;
-        setsockopt(b->fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
-        setsockopt(b->fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
-
-        /* Increase the buffers to a MB */
-        fd_inc_rcvbuf(b->fd, 1024*1024);
-        fd_inc_sndbuf(b->fd, 1024*1024);
-
-        return 0;
-}
-
-static int bus_start_auth(sd_bus *b) {
-        static const char auth_prefix[] = "\0AUTH EXTERNAL ";
-        static const char auth_suffix_with_unix_fd[] = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
-        static const char auth_suffix_without_unix_fd[] = "\r\nBEGIN\r\n";
-
-        char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
-        size_t l;
-        const char *auth_suffix;
-        int domain = 0, r;
-        socklen_t sl;
-
-        assert(b);
-
-        b->state = BUS_AUTHENTICATING;
-
-        sl = sizeof(domain);
-        r = getsockopt(b->fd, SOL_SOCKET, SO_DOMAIN, &domain, &sl);
-        if (r < 0)
-                return -errno;
-
-        if (domain != AF_UNIX)
-                b->negotiate_fds = false;
-
-        snprintf(text, sizeof(text), "%llu", (unsigned long long) geteuid());
-        char_array_0(text);
-
-        l = strlen(text);
-        b->auth_uid = hexmem(text, l);
-        if (!b->auth_uid)
-                return -ENOMEM;
-
-        auth_suffix = b->negotiate_fds ? auth_suffix_with_unix_fd : auth_suffix_without_unix_fd;
-
-        b->auth_iovec[0].iov_base = (void*) auth_prefix;
-        b->auth_iovec[0].iov_len = sizeof(auth_prefix) -1;
-        b->auth_iovec[1].iov_base = (void*) b->auth_uid;
-        b->auth_iovec[1].iov_len = l * 2;
-        b->auth_iovec[2].iov_base = (void*) auth_suffix;
-        b->auth_iovec[2].iov_len = strlen(auth_suffix);
-        b->auth_size = sizeof(auth_prefix) - 1 + l * 2 + sizeof(auth_suffix) - 1;
-
-        return bus_write_auth(b);
-}
-
-static int bus_connect(sd_bus *b) {
-        int r;
-
-        assert(b);
-        assert(b->fd < 0);
-        assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
-
-        b->fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
-        if (b->fd < 0)
-                return -errno;
-
-        r = bus_setup_fd(b);
-        if (r < 0)
-                return r;
-
-        r = connect(b->fd, &b->sockaddr.sa, b->sockaddr_size);
-        if (r < 0) {
-                if (errno == EINPROGRESS)
-                        return 1;
-
-                return -errno;
-        }
-
-        return bus_start_auth(b);
-}
-
-static int bus_exec(sd_bus *b) {
-        int s[2];
-        pid_t pid;
-
-        assert(b);
-        assert(b->fd < 0);
-        assert(b->exec_path);
-
-        b->fd = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
-        if (b->fd < 0)
-                return -errno;
-
-        pid = fork();
-        if (pid < 0) {
-                close_pipe(s);
-                return -errno;
-        }
-        if (pid == 0) {
-                /* Child */
-
-                close_all_fds(s, 2);
-                close_nointr_nofail(s[0]);
-
-                assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO);
-                assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO);
-
-                if (s[1] != STDIN_FILENO && s[1] != STDOUT_FILENO)
-                        close_nointr_nofail(s[1]);
-
-                fd_cloexec(STDIN_FILENO, false);
-                fd_cloexec(STDOUT_FILENO, false);
-                fd_nonblock(STDIN_FILENO, false);
-                fd_nonblock(STDOUT_FILENO, false);
-
-                if (b->exec_argv)
-                        execvp(b->exec_path, b->exec_argv);
-                else {
-                        const char *argv[] = { b->exec_path, NULL };
-                        execvp(b->exec_path, (char**) argv);
-                }
-
-                _exit(EXIT_FAILURE);
-        }
-
-        close_nointr_nofail(s[1]);
-        b->fd = s[0];
-
-        return bus_start_auth(b);
-}
-
-static int bus_start_connect(sd_bus *b) {
-        int r;
-
-        assert(b);
-
-        for (;;) {
-                if (b->fd >= 0) {
-                        close_nointr_nofail(b->fd);
-                        b->fd = -1;
-                }
-
-                if (b->sockaddr.sa.sa_family != AF_UNSPEC) {
-                        r = bus_connect(b);
-                        if (r >= 0)
-                                return r;
-
-                        b->last_connect_error = -r;
-
-                } else if (b->exec_path) {
-
-                        r = bus_exec(b);
-                        if (r >= 0)
-                                return r;
-
-                        b->last_connect_error = -r;
-                }
-
-                r = bus_parse_next_address(b);
-                if (r < 0)
-                        return r;
-                if (r == 0)
-                        return b->last_connect_error ? -b->last_connect_error : -ECONNREFUSED;
-        }
+        if (S_ISCHR(b->input_fd))
+                return bus_kernel_take_fd(b);
+        else
+                return bus_socket_take_fd(b);
 }
 
-static int bus_start_fd(sd_bus *b) {
+_public_ int sd_bus_start(sd_bus *bus) {
         int r;
 
-        assert(b);
-
-        r = fd_nonblock(b->fd, true);
-        if (r < 0)
-                return r;
-
-        r = fd_cloexec(b->fd, true);
-        if (r < 0)
-                return r;
-
-        r = bus_setup_fd(b);
-        if (r < 0)
-                return r;
-
-        return bus_start_auth(b);
-}
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-int sd_bus_start(sd_bus *bus) {
-        int r;
+        bus->state = BUS_OPENING;
 
-        if (!bus)
+        if (bus->is_server && bus->bus_client)
                 return -EINVAL;
-        if (bus->state != BUS_UNSET)
-                return -EPERM;
-
-        bus->state = BUS_OPENING;
 
-        if (bus->fd >= 0)
+        if (bus->input_fd >= 0)
                 r = bus_start_fd(bus);
-        else if (bus->address)
-                r = bus_start_connect(bus);
+        else if (bus->address || bus->sockaddr.sa.sa_family != AF_UNSPEC || bus->exec_path || bus->kernel || bus->machine)
+                r = bus_start_address(bus);
         else
                 return -EINVAL;
 
@@ -1029,19 +1036,18 @@ int sd_bus_start(sd_bus *bus) {
         return bus_send_hello(bus);
 }
 
-int sd_bus_open_system(sd_bus **ret) {
+_public_ int sd_bus_open_system(sd_bus **ret) {
         const char *e;
         sd_bus *b;
         int r;
 
-        if (!ret)
-                return -EINVAL;
+        assert_return(ret, -EINVAL);
 
         r = sd_bus_new(&b);
         if (r < 0)
                 return r;
 
-        e = getenv("DBUS_SYSTEM_BUS_ADDRESS");
+        e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
         if (e) {
                 r = sd_bus_set_address(b, e);
                 if (r < 0)
@@ -1052,7 +1058,7 @@ int sd_bus_open_system(sd_bus **ret) {
                 b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + sizeof("/run/dbus/system_bus_socket") - 1;
         }
 
-        b->send_hello = true;
+        b->bus_client = true;
 
         r = sd_bus_start(b);
         if (r < 0)
@@ -1066,26 +1072,25 @@ fail:
         return r;
 }
 
-int sd_bus_open_user(sd_bus **ret) {
+_public_ int sd_bus_open_user(sd_bus **ret) {
         const char *e;
         sd_bus *b;
         size_t l;
         int r;
 
-        if (!ret)
-                return -EINVAL;
+        assert_return(ret, -EINVAL);
 
         r = sd_bus_new(&b);
         if (r < 0)
                 return r;
 
-        e = getenv("DBUS_SESSION_BUS_ADDRESS");
+        e = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
         if (e) {
                 r = sd_bus_set_address(b, e);
                 if (r < 0)
                         goto fail;
         } else {
-                e = getenv("XDG_RUNTIME_DIR");
+                e = secure_getenv("XDG_RUNTIME_DIR");
                 if (!e) {
                         r = -ENOENT;
                         goto fail;
@@ -1102,7 +1107,7 @@ int sd_bus_open_user(sd_bus **ret) {
                 b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l + 4;
         }
 
-        b->send_hello = true;
+        b->bus_client = true;
 
         r = sd_bus_start(b);
         if (r < 0)
@@ -1116,56 +1121,151 @@ fail:
         return r;
 }
 
-void sd_bus_close(sd_bus *bus) {
+_public_ int sd_bus_open_system_remote(const char *host, sd_bus **ret) {
+        _cleanup_free_ char *e = NULL;
+        char *p = NULL;
+        sd_bus *bus;
+        int r;
+
+        assert_return(host, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        e = bus_address_escape(host);
+        if (!e)
+                return -ENOMEM;
+
+        p = strjoin("unixexec:path=ssh,argv1=-xT,argv2=", e, ",argv3=systemd-stdio-bridge", NULL);
+        if (!p)
+                return -ENOMEM;
+
+        r = sd_bus_new(&bus);
+        if (r < 0) {
+                free(p);
+                return r;
+        }
+
+        bus->address = p;
+        bus->bus_client = true;
+
+        r = sd_bus_start(bus);
+        if (r < 0) {
+                bus_free(bus);
+                return r;
+        }
+
+        *ret = bus;
+        return 0;
+}
+
+_public_ int sd_bus_open_system_container(const char *machine, sd_bus **ret) {
+        _cleanup_free_ char *e = NULL;
+        sd_bus *bus;
+        char *p;
+        int r;
+
+        assert_return(machine, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        e = bus_address_escape(machine);
+        if (!e)
+                return -ENOMEM;
+
+        p = strjoin("x-container:machine=", e, NULL);
+        if (!p)
+                return -ENOMEM;
+
+        r = sd_bus_new(&bus);
+        if (r < 0) {
+                free(p);
+                return r;
+        }
+
+        bus->address = p;
+        bus->bus_client = true;
+
+        r = sd_bus_start(bus);
+        if (r < 0) {
+                bus_free(bus);
+                return r;
+        }
+
+        *ret = bus;
+        return 0;
+}
+
+_public_ void sd_bus_close(sd_bus *bus) {
+
         if (!bus)
                 return;
-        if (bus->fd < 0)
+        if (bus->state == BUS_CLOSED)
+                return;
+        if (bus_pid_changed(bus))
+                return;
+
+        bus->state = 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);
+
+        if (!bus->is_kernel)
+                bus_close_fds(bus);
+
+        /* We'll leave the fd open in case this is a kernel bus, since
+         * there might still be memblocks around that reference this
+         * bus, and they might need to invoke the
+         * KDBUS_CMD_MSG_RELEASE ioctl on the fd when they are
+         * freed. */
+}
+
+static void bus_enter_closing(sd_bus *bus) {
+        assert(bus);
+
+        if (bus->state != BUS_OPENING &&
+            bus->state != BUS_AUTHENTICATING &&
+            bus->state != BUS_HELLO &&
+            bus->state != BUS_RUNNING)
                 return;
 
-        close_nointr_nofail(bus->fd);
-        bus->fd = -1;
+        bus->state = BUS_CLOSING;
 }
 
-sd_bus *sd_bus_ref(sd_bus *bus) {
-        if (!bus)
-                return NULL;
+_public_ sd_bus *sd_bus_ref(sd_bus *bus) {
+        assert_return(bus, NULL);
 
-        assert(bus->n_ref > 0);
+        assert_se(REFCNT_INC(bus->n_ref) >= 2);
 
-        bus->n_ref++;
         return bus;
 }
 
-sd_bus *sd_bus_unref(sd_bus *bus) {
-        if (!bus)
-                return NULL;
+_public_ sd_bus *sd_bus_unref(sd_bus *bus) {
+        assert_return(bus, NULL);
 
-        assert(bus->n_ref > 0);
-        bus->n_ref--;
-
-        if (bus->n_ref <= 0)
+        if (REFCNT_DEC(bus->n_ref) <= 0)
                 bus_free(bus);
 
         return NULL;
 }
 
-int sd_bus_is_open(sd_bus *bus) {
-        if (!bus)
-                return -EINVAL;
+_public_ int sd_bus_is_open(sd_bus *bus) {
+
+        assert_return(bus, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-        return bus->state != BUS_UNSET && bus->fd >= 0;
+        return BUS_IS_OPEN(bus->state);
 }
 
-int sd_bus_can_send(sd_bus *bus, char type) {
+_public_ int sd_bus_can_send(sd_bus *bus, char type) {
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert_return(bus, -EINVAL);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         if (type == SD_BUS_TYPE_UNIX_FD) {
-                if (!bus->negotiate_fds)
+                if (!(bus->hello_flags & KDBUS_HELLO_ACCEPT_FD))
                         return 0;
 
                 r = bus_ensure_running(bus);
@@ -1178,19 +1278,18 @@ int sd_bus_can_send(sd_bus *bus, char type) {
         return bus_type_is_valid(type);
 }
 
-int sd_bus_get_peer(sd_bus *bus, sd_id128_t *peer) {
+_public_ int sd_bus_get_server_id(sd_bus *bus, sd_id128_t *server_id) {
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (!peer)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(server_id, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         r = bus_ensure_running(bus);
         if (r < 0)
                 return r;
 
-        *peer = bus->peer;
+        *server_id = bus->server_id;
         return 0;
 }
 
@@ -1200,259 +1299,46 @@ static int bus_seal_message(sd_bus *b, sd_bus_message *m) {
         if (m->header->version > b->message_version)
                 return -EPERM;
 
-        if (m->sealed)
+        if (m->sealed) {
+                /* If we copy the same message to multiple
+                 * destinations, avoid using the same serial
+                 * numbers. */
+                b->serial = MAX(b->serial, BUS_MESSAGE_SERIAL(m));
                 return 0;
+        }
 
         return bus_message_seal(m, ++b->serial);
 }
 
-static int message_write(sd_bus *bus, sd_bus_message *m, size_t *idx) {
-        struct msghdr mh;
-        struct iovec *iov;
-        ssize_t k;
-        size_t n;
-        unsigned j;
+static int bus_write_message(sd_bus *bus, sd_bus_message *message, size_t *idx) {
+        int r;
 
         assert(bus);
-        assert(m);
-        assert(idx);
-        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
-
-        if (*idx >= m->size)
-                return 0;
-        zero(mh);
-
-        if (m->n_fds > 0) {
-                struct cmsghdr *control;
-                control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
-
-                mh.msg_control = control;
-                control->cmsg_level = SOL_SOCKET;
-                control->cmsg_type = SCM_RIGHTS;
-                mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
-                memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
-        }
-
-        n = m->n_iovec * sizeof(struct iovec);
-        iov = alloca(n);
-        memcpy(iov, m->iovec, n);
-
-        j = 0;
-        iovec_advance(iov, &j, *idx);
+        assert(message);
 
-        mh.msg_iov = iov;
-        mh.msg_iovlen = m->n_iovec;
-
-        k = sendmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
+        if (bus->is_kernel)
+                r = bus_kernel_write_message(bus, message);
+        else
+                r = bus_socket_write_message(bus, message, idx);
 
-        *idx += (size_t) k;
-        return 1;
+        return r;
 }
 
-static int message_read_need(sd_bus *bus, size_t *need) {
-        uint32_t a, b;
-        uint8_t e;
-        uint64_t sum;
+static int dispatch_wqueue(sd_bus *bus) {
+        int r, ret = 0;
 
         assert(bus);
-        assert(need);
         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
-        if (bus->rbuffer_size < sizeof(struct bus_header)) {
-                *need = sizeof(struct bus_header) + 8;
-
-                /* Minimum message size:
-                 *
-                 * Header +
-                 *
-                 *  Method Call: +2 string headers
-                 *       Signal: +3 string headers
-                 * Method Error: +1 string headers
-                 *               +1 uint32 headers
-                 * Method Reply: +1 uint32 headers
-                 *
-                 * A string header is at least 9 bytes
-                 * A uint32 header is at least 8 bytes
-                 *
-                 * Hence the minimum message size of a valid message
-                 * is header + 8 bytes */
-
-                return 0;
-        }
-
-        a = ((const uint32_t*) bus->rbuffer)[1];
-        b = ((const uint32_t*) bus->rbuffer)[3];
-
-        e = ((const uint8_t*) bus->rbuffer)[0];
-        if (e == SD_BUS_LITTLE_ENDIAN) {
-                a = le32toh(a);
-                b = le32toh(b);
-        } else if (e == SD_BUS_BIG_ENDIAN) {
-                a = be32toh(a);
-                b = be32toh(b);
-        } else
-                return -EBADMSG;
-
-        sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a;
-        if (sum >= BUS_MESSAGE_SIZE_MAX)
-                return -ENOBUFS;
+        while (bus->wqueue_size > 0) {
 
-        *need = (size_t) sum;
-        return 0;
-}
-
-static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
-        sd_bus_message *t;
-        void *b;
-        int r;
-
-        assert(bus);
-        assert(m);
-        assert(bus->rbuffer_size >= size);
-        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
-
-        if (bus->rbuffer_size > size) {
-                b = memdup((const uint8_t*) bus->rbuffer + size,
-                           bus->rbuffer_size - size);
-                if (!b)
-                        return -ENOMEM;
-        } else
-                b = NULL;
-
-        r = bus_message_from_malloc(bus->rbuffer, size,
-                                    bus->fds, bus->n_fds,
-                                    bus->ucred_valid ? &bus->ucred : NULL,
-                                    bus->label[0] ? bus->label : NULL,
-                                    &t);
-        if (r < 0) {
-                free(b);
-                return r;
-        }
-
-        bus->rbuffer = b;
-        bus->rbuffer_size -= size;
-
-        bus->fds = NULL;
-        bus->n_fds = 0;
-
-        *m = t;
-        return 1;
-}
-
-static int message_read(sd_bus *bus, sd_bus_message **m) {
-        struct msghdr mh;
-        struct iovec iov;
-        ssize_t k;
-        size_t need;
-        int r;
-        void *b;
-        union {
-                struct cmsghdr cmsghdr;
-                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
-                            CMSG_SPACE(sizeof(struct ucred)) +
-                            CMSG_SPACE(NAME_MAX)]; /*selinux label */
-        } control;
-        struct cmsghdr *cmsg;
-
-        assert(bus);
-        assert(m);
-        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
-
-        r = message_read_need(bus, &need);
-        if (r < 0)
-                return r;
-
-        if (bus->rbuffer_size >= need)
-                return message_make(bus, need, m);
-
-        b = realloc(bus->rbuffer, need);
-        if (!b)
-                return -ENOMEM;
-
-        bus->rbuffer = b;
-
-        zero(iov);
-        iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size;
-        iov.iov_len = need - bus->rbuffer_size;
-
-        zero(mh);
-        mh.msg_iov = &iov;
-        mh.msg_iovlen = 1;
-        mh.msg_control = &control;
-        mh.msg_controllen = sizeof(control);
-
-        k = recvmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
-        if (k == 0)
-                return -ECONNRESET;
-
-        bus->rbuffer_size += k;
-
-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
-                if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_RIGHTS) {
-                        int n, *f;
-
-                        n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
-
-                        f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
-                        if (!f) {
-                                close_many((int*) CMSG_DATA(cmsg), n);
-                                return -ENOMEM;
-                        }
-
-                        memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
-                        bus->fds = f;
-                        bus->n_fds += n;
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_CREDENTIALS &&
-                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
-
-                        memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
-                        bus->ucred_valid = true;
-
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                         cmsg->cmsg_type == SCM_SECURITY) {
-
-                        size_t l;
-                        l = cmsg->cmsg_len - CMSG_LEN(0);
-                        memcpy(&bus->label, CMSG_DATA(cmsg), l);
-                        bus->label[l] = 0;
-                }
-        }
-
-        r = message_read_need(bus, &need);
-        if (r < 0)
-                return r;
-
-        if (bus->rbuffer_size >= need)
-                return message_make(bus, need, m);
-
-        return 1;
-}
-
-static int dispatch_wqueue(sd_bus *bus) {
-        int r, ret = 0;
-
-        assert(bus);
-        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
-
-        if (bus->fd < 0)
-                return -ENOTCONN;
-
-        while (bus->wqueue_size > 0) {
-
-                r = message_write(bus, bus->wqueue[0], &bus->windex);
-                if (r < 0) {
-                        sd_bus_close(bus);
+                r = bus_write_message(bus, bus->wqueue[0], &bus->windex);
+                if (r < 0)
                         return r;
-                else if (r == 0)
+                else if (r == 0)
                         /* Didn't do anything this time */
                         return ret;
-                else if (bus->windex >= bus->wqueue[0]->size) {
+                else if (bus->is_kernel || bus->windex >= BUS_MESSAGE_SIZE(bus->wqueue[0])) {
                         /* Fully written. Let's drop the entry from
                          * the queue.
                          *
@@ -1475,6 +1361,20 @@ static int dispatch_wqueue(sd_bus *bus) {
         return ret;
 }
 
+static int bus_read_message(sd_bus *bus, sd_bus_message **m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (bus->is_kernel)
+                r = bus_kernel_read_message(bus, m);
+        else
+                r = bus_socket_read_message(bus, m);
+
+        return r;
+}
+
 static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
         sd_bus_message *z = NULL;
         int r, ret = 0;
@@ -1483,9 +1383,6 @@ static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
         assert(m);
         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
-        if (bus->fd < 0)
-                return -ENOTCONN;
-
         if (bus->rqueue_size > 0) {
                 /* Dispatch a queued message */
 
@@ -1497,32 +1394,26 @@ static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
 
         /* Try to read a new message */
         do {
-                r = message_read(bus, &z);
-                if (r < 0) {
-                        sd_bus_close(bus);
+                r = bus_read_message(bus, &z);
+                if (r < 0)
                         return r;
-                }
                 if (r == 0)
                         return ret;
 
-                r = 1;
+                ret = 1;
         } while (!z);
 
         *m = z;
-        return 1;
+        return ret;
 }
 
-int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
+_public_ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
-        if (!m)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        assert_return(m, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         if (m->n_fds > 0) {
                 r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
@@ -1544,16 +1435,15 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
         /* If this is a reply and no reply was requested, then let's
          * suppress this, if we can */
         if (m->dont_send && !serial)
-                return 0;
+                return 1;
 
         if ((bus->state == BUS_RUNNING || bus->state == BUS_HELLO) && bus->wqueue_size <= 0) {
                 size_t idx = 0;
 
-                r = message_write(bus, m, &idx);
-                if (r < 0) {
-                        sd_bus_close(bus);
+                r = bus_write_message(bus, m, &idx);
+                if (r < 0)
                         return r;
-                } else if (idx < m->size)  {
+                else if (!bus->is_kernel && 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
@@ -1582,7 +1472,28 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
         if (serial)
                 *serial = BUS_MESSAGE_SERIAL(m);
 
-        return 0;
+        return 1;
+}
+
+_public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destination, uint64_t *serial) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        assert_return(m, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        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, serial);
 }
 
 static usec_t calc_elapse(uint64_t usec) {
@@ -1613,10 +1524,10 @@ static int timeout_compare(const void *a, const void *b) {
         return 0;
 }
 
-int sd_bus_send_with_reply(
+_public_ int sd_bus_call_async(
                 sd_bus *bus,
                 sd_bus_message *m,
-                sd_message_handler_t callback,
+                sd_bus_message_handler_t callback,
                 void *userdata,
                 uint64_t usec,
                 uint64_t *serial) {
@@ -1624,20 +1535,13 @@ int sd_bus_send_with_reply(
         struct reply_callback *c;
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
-        if (!m)
-                return -EINVAL;
-        if (!callback)
-                return -EINVAL;
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
-                return -EINVAL;
-        if (m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        assert_return(m, -EINVAL);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(!(m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         r = hashmap_ensure_allocated(&bus->reply_callbacks, uint64_hash_func, uint64_compare_func);
         if (r < 0)
@@ -1653,7 +1557,7 @@ int sd_bus_send_with_reply(
         if (r < 0)
                 return r;
 
-        c = new(struct reply_callback, 1);
+        c = new0(struct reply_callback, 1);
         if (!c)
                 return -ENOMEM;
 
@@ -1672,27 +1576,26 @@ int sd_bus_send_with_reply(
                 r = prioq_put(bus->reply_callbacks_prioq, c, &c->prioq_idx);
                 if (r < 0) {
                         c->timeout = 0;
-                        sd_bus_send_with_reply_cancel(bus, c->serial);
+                        sd_bus_call_async_cancel(bus, c->serial);
                         return r;
                 }
         }
 
         r = sd_bus_send(bus, m, serial);
         if (r < 0) {
-                sd_bus_send_with_reply_cancel(bus, c->serial);
+                sd_bus_call_async_cancel(bus, c->serial);
                 return r;
         }
 
         return r;
 }
 
-int sd_bus_send_with_reply_cancel(sd_bus *bus, uint64_t serial) {
+_public_ int sd_bus_call_async_cancel(sd_bus *bus, uint64_t serial) {
         struct reply_callback *c;
 
-        if (!bus)
-                return -EINVAL;
-        if (serial == 0)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(serial != 0, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         c = hashmap_remove(bus->reply_callbacks, &serial);
         if (!c)
@@ -1710,11 +1613,8 @@ int bus_ensure_running(sd_bus *bus) {
 
         assert(bus);
 
-        if (bus->fd < 0)
+        if (bus->state == BUS_UNSET || bus->state == BUS_CLOSED || bus->state == BUS_CLOSING)
                 return -ENOTCONN;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-
         if (bus->state == BUS_RUNNING)
                 return 1;
 
@@ -1733,7 +1633,7 @@ int bus_ensure_running(sd_bus *bus) {
         }
 }
 
-int sd_bus_send_with_reply_and_block(
+_public_ int sd_bus_call(
                 sd_bus *bus,
                 sd_bus_message *m,
                 uint64_t usec,
@@ -1745,20 +1645,13 @@ int sd_bus_send_with_reply_and_block(
         uint64_t serial;
         bool room = false;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->fd < 0)
-                return -ENOTCONN;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (!m)
-                return -EINVAL;
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
-                return -EINVAL;
-        if (m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
-                return -EINVAL;
-        if (bus_error_is_dirty(error))
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
+        assert_return(m, -EINVAL);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(!(m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL);
+        assert_return(!bus_error_is_dirty(error), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         r = bus_ensure_running(bus);
         if (r < 0)
@@ -1791,20 +1684,26 @@ int sd_bus_send_with_reply_and_block(
                         room = true;
                 }
 
-                r = message_read(bus, &incoming);
+                r = bus_read_message(bus, &incoming);
                 if (r < 0)
                         return r;
+
                 if (incoming) {
 
                         if (incoming->reply_serial == serial) {
                                 /* Found a match! */
 
-                                if (incoming->header->type == SD_BUS_MESSAGE_TYPE_METHOD_RETURN) {
-                                        *reply = incoming;
-                                        return 0;
+                                if (incoming->header->type == SD_BUS_MESSAGE_METHOD_RETURN) {
+
+                                        if (reply)
+                                                *reply = incoming;
+                                        else
+                                                sd_bus_message_unref(incoming);
+
+                                        return 1;
                                 }
 
-                                if (incoming->header->type == SD_BUS_MESSAGE_TYPE_METHOD_ERROR) {
+                                if (incoming->header->type == SD_BUS_MESSAGE_METHOD_ERROR) {
                                         int k;
 
                                         r = sd_bus_error_copy(error, &incoming->error);
@@ -1813,13 +1712,26 @@ int sd_bus_send_with_reply_and_block(
                                                 return r;
                                         }
 
-                                        k = bus_error_to_errno(&incoming->error);
+                                        k = sd_bus_error_get_errno(&incoming->error);
                                         sd_bus_message_unref(incoming);
-                                        return k;
+                                        return -k;
                                 }
 
                                 sd_bus_message_unref(incoming);
                                 return -EIO;
+
+                        } else if (incoming->header->serial == serial &&
+                                   bus->unique_name &&
+                                   incoming->sender &&
+                                   streq(bus->unique_name, incoming->sender)) {
+
+                                /* Our own message? Somebody is trying
+                                 * to send its own client a message,
+                                 * let's not dead-lock, let's fail
+                                 * immediately. */
+
+                                sd_bus_message_unref(incoming);
+                                return -ELOOP;
                         }
 
                         /* There's already guaranteed to be room for
@@ -1854,31 +1766,27 @@ int sd_bus_send_with_reply_and_block(
         }
 }
 
-int sd_bus_get_fd(sd_bus *bus) {
-        if (!bus)
-                return -EINVAL;
+_public_ int sd_bus_get_fd(sd_bus *bus) {
 
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert_return(bus, -EINVAL);
+        assert_return(bus->input_fd == bus->output_fd, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-        return bus->fd;
+        return bus->input_fd;
 }
 
-int sd_bus_get_events(sd_bus *bus) {
+_public_ int sd_bus_get_events(sd_bus *bus) {
         int flags = 0;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert_return(bus, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state) || bus->state == BUS_CLOSING, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         if (bus->state == BUS_OPENING)
                 flags |= POLLOUT;
         else if (bus->state == BUS_AUTHENTICATING) {
 
-                if (bus->auth_index < ELEMENTSOF(bus->auth_iovec))
+                if (bus_socket_auth_needs_write(bus))
                         flags |= POLLOUT;
 
                 flags |= POLLIN;
@@ -1893,35 +1801,47 @@ int sd_bus_get_events(sd_bus *bus) {
         return flags;
 }
 
-int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
+_public_ int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
         struct reply_callback *c;
 
-        if (!bus)
-                return -EINVAL;
-        if (!timeout_usec)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert_return(bus, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(BUS_IS_OPEN(bus->state) || bus->state == BUS_CLOSING, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING) {
+                *timeout_usec = 0;
+                return 1;
+        }
 
         if (bus->state == BUS_AUTHENTICATING) {
                 *timeout_usec = bus->auth_timeout;
                 return 1;
         }
 
-        if (bus->state != BUS_RUNNING && bus->state != BUS_HELLO)
+        if (bus->state != BUS_RUNNING && bus->state != BUS_HELLO) {
+                *timeout_usec = (uint64_t) -1;
                 return 0;
+        }
+
+        if (bus->rqueue_size > 0) {
+                *timeout_usec = 0;
+                return 1;
+        }
 
         c = prioq_peek(bus->reply_callbacks_prioq);
-        if (!c)
+        if (!c) {
+                *timeout_usec = (uint64_t) -1;
                 return 0;
+        }
 
         *timeout_usec = c->timeout;
         return 1;
 }
 
 static int process_timeout(sd_bus *bus) {
+        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_bus_message_unref_ sd_bus_message* m = NULL;
         struct reply_callback *c;
         usec_t n;
         int r;
@@ -1936,24 +1856,65 @@ static int process_timeout(sd_bus *bus) {
         if (c->timeout > n)
                 return 0;
 
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->serial,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Method call timed out"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = bus_seal_message(bus, m);
+        if (r < 0)
+                return r;
+
         assert_se(prioq_pop(bus->reply_callbacks_prioq) == c);
         hashmap_remove(bus->reply_callbacks, &c->serial);
 
-        r = c->callback(bus, ETIMEDOUT, NULL, c->userdata);
+        bus->current = m;
+        bus->iteration_counter ++;
+
+        r = c->callback(bus, m, c->userdata, &error_buffer);
+        r = bus_maybe_reply_error(m, r, &error_buffer);
         free(c);
 
-        return r < 0 ? r : 1;
+        bus->current = NULL;
+
+        return r;
+}
+
+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 (m->header->type != SD_BUS_MESSAGE_METHOD_RETURN &&
+            m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
+                return -EIO;
+
+        if (m->reply_serial != bus->hello_serial)
+                return -EIO;
+
+        return 0;
 }
 
 static int process_reply(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         struct reply_callback *c;
         int r;
 
         assert(bus);
         assert(m);
 
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_RETURN &&
-            m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_ERROR)
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_RETURN &&
+            m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
                 return 0;
 
         c = hashmap_remove(bus->reply_callbacks, &m->reply_serial);
@@ -1963,21 +1924,69 @@ static int process_reply(sd_bus *bus, sd_bus_message *m) {
         if (c->timeout != 0)
                 prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
 
-        r = c->callback(bus, 0, m, c->userdata);
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        r = c->callback(bus, m, c->userdata, &error_buffer);
+        r = bus_maybe_reply_error(m, r, &error_buffer);
         free(c);
 
         return r;
 }
 
 static int process_filter(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         struct filter_callback *l;
         int r;
 
-        LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
-                r = l->callback(bus, 0, m, l->userdata);
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->filter_callbacks_modified = false;
+
+                LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
+
+                        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;
+
+                        r = l->callback(bus, m, l->userdata, &error_buffer);
+                        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;
 }
@@ -1989,7 +1998,7 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
         assert(bus);
         assert(m);
 
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
                 return 0;
 
         if (!streq_ptr(m->interface, "org.freedesktop.DBus.Peer"))
@@ -1999,7 +2008,7 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
                 return 1;
 
         if (streq_ptr(m->member, "Ping"))
-                r = sd_bus_message_new_method_return(bus, m, &reply);
+                r = sd_bus_message_new_method_return(m, &reply);
         else if (streq_ptr(m->member, "GetMachineId")) {
                 sd_id128_t id;
                 char sid[33];
@@ -2008,19 +2017,16 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
                 if (r < 0)
                         return r;
 
-                r = sd_bus_message_new_method_return(bus, m, &reply);
+                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, sid));
         } else {
-                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_INIT;
-
-                sd_bus_error_set(&error,
-                                 "org.freedesktop.DBus.Error.UnknownMethod",
+                r = sd_bus_message_new_method_errorf(
+                                m, &reply,
+                                SD_BUS_ERROR_UNKNOWN_METHOD,
                                  "Unknown method '%s' on interface '%s'.", m->member, m->interface);
-
-                r = sd_bus_message_new_method_error(bus, m, &error, &reply);
         }
 
         if (r < 0)
@@ -2033,280 +2039,330 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
         return 1;
 }
 
-static int process_object(sd_bus *bus, sd_bus_message *m) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_INIT;
-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-        struct object_callback *c;
-        char *p;
+static int process_message(sd_bus *bus, sd_bus_message *m) {
         int r;
-        bool found = false;
 
         assert(bus);
         assert(m);
 
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
-                return 0;
+        bus->current = m;
+        bus->iteration_counter++;
 
-        if (hashmap_isempty(bus->object_callbacks))
-                return 0;
+        log_debug("Got message 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)));
 
-        c = hashmap_get(bus->object_callbacks, m->path);
-        if (c) {
-                r = c->callback(bus, 0, m, c->userdata);
-                if (r != 0)
-                        return r;
+        r = process_hello(bus, m);
+        if (r != 0)
+                goto finish;
 
-                found = true;
-        }
+        r = process_reply(bus, m);
+        if (r != 0)
+                goto finish;
 
-        /* Look for fallback prefixes */
-        p = strdupa(m->path);
-        for (;;) {
-                char *e;
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
 
-                e = strrchr(p, '/');
-                if (e == p || !e)
-                        break;
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
 
-                *e = 0;
+        r = process_builtin(bus, m);
+        if (r != 0)
+                goto finish;
 
-                c = hashmap_get(bus->object_callbacks, p);
-                if (c && c->is_fallback) {
-                        r = c->callback(bus, 0, m, c->userdata);
-                        if (r != 0)
-                                return r;
+        r = bus_process_object(bus, m);
 
-                        found = true;
-                }
-        }
+finish:
+        bus->current = NULL;
+        return r;
+}
 
-        if (!found)
-                return 0;
+static int process_running(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
 
-        sd_bus_error_set(&error,
-                         "org.freedesktop.DBus.Error.UnknownMethod",
-                         "Unknown method '%s' or interface '%s'.", m->member, m->interface);
+        assert(bus);
+        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
+
+        r = process_timeout(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_wqueue(bus);
+        if (r != 0)
+                goto null_message;
 
-        r = sd_bus_message_new_method_error(bus, m, &error, &reply);
+        r = dispatch_rqueue(bus, &m);
         if (r < 0)
                 return r;
+        if (!m)
+                goto null_message;
 
-        r = sd_bus_send(bus, reply, NULL);
-        if (r < 0)
-                return r;
+        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 = m;
+                m = NULL;
+                return 1;
+        }
+
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) {
+
+                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 process_message(sd_bus *bus, sd_bus_message *m) {
+static int process_closing(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        struct reply_callback *c;
         int r;
 
         assert(bus);
-        assert(m);
+        assert(bus->state == BUS_CLOSING);
 
-        r = process_reply(bus, m);
-        if (r != 0)
-                return r;
+        c = hashmap_first(bus->reply_callbacks);
+        if (c) {
+                _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+
+                /* First, fail all outstanding method calls */
+                r = bus_message_new_synthetic_error(
+                                bus,
+                                c->serial,
+                                &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Connection terminated"),
+                                &m);
+                if (r < 0)
+                        return r;
 
-        r = process_filter(bus, m);
-        if (r != 0)
-                return r;
+                r = bus_seal_message(bus, m);
+                if (r < 0)
+                        return r;
 
-        r = process_builtin(bus, m);
-        if (r != 0)
-                return r;
+                if (c->timeout != 0)
+                        prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
 
-        return process_object(bus, m);
-}
+                hashmap_remove(bus->reply_callbacks, &c->serial);
 
-int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
-        int r;
+                bus->current = m;
+                bus->iteration_counter++;
 
-        /* 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. */
+                r = c->callback(bus, m, c->userdata, &error_buffer);
+                r = bus_maybe_reply_error(m, r, &error_buffer);
+                free(c);
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+                goto finish;
+        }
 
-        if (bus->state == BUS_OPENING) {
-                struct pollfd p;
+        /* Then, synthesize a Disconnected message */
+        r = sd_bus_message_new_signal(
+                        bus,
+                        "/org/freedesktop/DBus/Local",
+                        "org.freedesktop.DBus.Local",
+                        "Disconnected",
+                        &m);
+        if (r < 0)
+                return r;
 
-                zero(p);
-                p.fd = bus->fd;
-                p.events = POLLOUT;
+        r = bus_seal_message(bus, m);
+        if (r < 0)
+                return r;
 
-                r = poll(&p, 1, 0);
-                if (r < 0)
-                        return -errno;
+        sd_bus_close(bus);
 
-                if (p.revents & (POLLOUT|POLLERR|POLLHUP)) {
-                        int error = 0;
-                        socklen_t slen = sizeof(error);
+        bus->current = m;
+        bus->iteration_counter++;
 
-                        r = getsockopt(bus->fd, SOL_SOCKET, SO_ERROR, &error, &slen);
-                        if (r < 0)
-                                bus->last_connect_error = errno;
-                        else if (error != 0)
-                                bus->last_connect_error = error;
-                        else if (p.revents & (POLLERR|POLLHUP))
-                                bus->last_connect_error = ECONNREFUSED;
-                        else {
-                                r = bus_start_auth(bus);
-                                goto null_message;
-                        }
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
 
-                        /* Try next address */
-                        bus_reset_parsed_address(bus);
-                        r = bus_start_connect(bus);
-                        goto null_message;
-                }
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
 
-                r = 0;
-                goto null_message;
+        if (ret) {
+                *ret = m;
+                m = NULL;
+        }
 
-        } else if (bus->state == BUS_AUTHENTICATING) {
+        r = 1;
 
-                if (now(CLOCK_MONOTONIC) >= bus->auth_timeout)
-                        return -ETIMEDOUT;
+finish:
+        bus->current = NULL;
+        return r;
+}
 
-                r = bus_write_auth(bus);
-                if (r != 0)
-                        goto null_message;
+_public_ int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
+        BUS_DONT_DESTROY(bus);
+        int r;
 
-                r = bus_read_auth(bus);
-                goto null_message;
+        /* 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. */
 
-        } else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
-                _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-                int k;
+        assert_return(bus, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-                r = process_timeout(bus);
-                if (r != 0)
-                        goto null_message;
+        /* We don't allow recursively invoking sd_bus_process(). */
+        assert_return(!bus->current, -EBUSY);
 
-                r = dispatch_wqueue(bus);
-                if (r != 0)
-                        goto null_message;
+        switch (bus->state) {
 
-                k = r;
-                r = dispatch_rqueue(bus, &m);
-                if (r < 0)
-                        return r;
-                if (!m) {
-                        if (r == 0)
-                                r = k;
-                        goto null_message;
-                }
+        case BUS_UNSET:
+        case BUS_CLOSED:
+                return -ENOTCONN;
 
-                r = process_message(bus, m);
-                if (r != 0)
-                        goto null_message;
+        case BUS_OPENING:
+                r = bus_socket_process_opening(bus);
+                if (r == -ECONNRESET || r == -EPIPE) {
+                        bus_enter_closing(bus);
+                        r = 1;
+                } else if (r < 0)
+                        return r;
+                if (ret)
+                        *ret = NULL;
+                return r;
 
-                if (ret) {
-                        *ret = m;
-                        m = NULL;
-                        return 1;
-                }
+        case BUS_AUTHENTICATING:
+                r = bus_socket_process_authenticating(bus);
+                if (r == -ECONNRESET || r == -EPIPE) {
+                        bus_enter_closing(bus);
+                        r = 1;
+                } else if (r < 0)
+                        return r;
 
-                if (m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_CALL) {
-                        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-                        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_INIT;
+                if (ret)
+                        *ret = NULL;
 
-                        sd_bus_error_set(&error, "org.freedesktop.DBus.Error.UnknownObject", "Unknown object '%s'.", m->path);
+                return r;
 
-                        r = sd_bus_message_new_method_error(bus, m, &error, &reply);
-                        if (r < 0)
-                                return r;
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                r = process_running(bus, ret);
+                if (r == -ECONNRESET || r == -EPIPE) {
+                        bus_enter_closing(bus);
+                        r = 1;
 
-                        r = sd_bus_send(bus, reply, NULL);
-                        if (r < 0)
-                                return r;
+                        if (ret)
+                                *ret = NULL;
                 }
 
-                return 1;
+                return r;
+
+        case BUS_CLOSING:
+                return process_closing(bus, ret);
         }
 
         assert_not_reached("Unknown state");
-
-null_message:
-        if (r >= 0 && ret)
-                *ret = NULL;
-
-        return r;
 }
 
 static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
-        struct pollfd p;
-        int r, e;
+        struct pollfd p[2] = {};
+        int r, e, n;
         struct timespec ts;
-        usec_t until, m;
+        usec_t m = (usec_t) -1;
 
         assert(bus);
 
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        if (bus->state == BUS_CLOSING)
+                return 1;
+
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
 
         e = sd_bus_get_events(bus);
         if (e < 0)
                 return e;
 
         if (need_more)
+                /* The caller really needs some more data, he doesn't
+                 * care about what's already read, or any timeouts
+                 * except its own.*/
                 e |= POLLIN;
-
-        r = sd_bus_get_timeout(bus, &until);
-        if (r < 0)
-                return r;
-        if (r == 0)
-                m = (uint64_t) -1;
         else {
-                usec_t n;
-                n = now(CLOCK_MONOTONIC);
-                m = until > n ? until - n : 0;
+                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) {
+                        usec_t nw;
+                        nw = now(CLOCK_MONOTONIC);
+                        m = until > nw ? until - nw : 0;
+                }
         }
 
         if (timeout_usec != (uint64_t) -1 && (m == (uint64_t) -1 || timeout_usec < m))
                 m = timeout_usec;
 
-        zero(p);
-        p.fd = bus->fd;
-        p.events = e;
+        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;
+        }
 
-        r = ppoll(&p, 1, m == (uint64_t) -1 ? NULL : timespec_store(&ts, m), NULL);
+        r = ppoll(p, n, m == (uint64_t) -1 ? NULL : timespec_store(&ts, m), NULL);
         if (r < 0)
                 return -errno;
 
         return r > 0 ? 1 : 0;
 }
 
-int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
+_public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
+
+        assert_return(bus, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        assert_return(BUS_IS_OPEN(bus->state) , -ENOTCONN);
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
         if (bus->rqueue_size > 0)
                 return 0;
 
         return bus_poll(bus, false, timeout_usec);
 }
 
-int sd_bus_flush(sd_bus *bus) {
+_public_ int sd_bus_flush(sd_bus *bus) {
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->state == BUS_UNSET)
-                return -ENOTCONN;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert_return(bus, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        assert_return(BUS_IS_OPEN(bus->state), -ENOTCONN);
 
         r = bus_ensure_running(bus);
         if (r < 0)
@@ -2329,35 +2385,41 @@ int sd_bus_flush(sd_bus *bus) {
         }
 }
 
-int sd_bus_add_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata) {
+_public_ int sd_bus_add_filter(sd_bus *bus,
+                               sd_bus_message_handler_t callback,
+                               void *userdata) {
+
         struct filter_callback *f;
 
-        if (!bus)
-                return -EINVAL;
-        if (!callback)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
-        f = new(struct filter_callback, 1);
+        f = new0(struct filter_callback, 1);
         if (!f)
                 return -ENOMEM;
         f->callback = callback;
         f->userdata = userdata;
 
-        LIST_PREPEND(struct filter_callback, callbacks, bus->filter_callbacks, f);
+        bus->filter_callbacks_modified = true;
+        LIST_PREPEND(callbacks, bus->filter_callbacks, f);
         return 0;
 }
 
-int sd_bus_remove_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata) {
+_public_ int sd_bus_remove_filter(sd_bus *bus,
+                                  sd_bus_message_handler_t callback,
+                                  void *userdata) {
+
         struct filter_callback *f;
 
-        if (!bus)
-                return -EINVAL;
-        if (!callback)
-                return -EINVAL;
+        assert_return(bus, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
 
         LIST_FOREACH(callbacks, f, bus->filter_callbacks) {
                 if (f->callback == callback && f->userdata == userdata) {
-                        LIST_REMOVE(struct filter_callback, callbacks, bus->filter_callbacks, f);
+                        bus->filter_callbacks_modified = true;
+                        LIST_REMOVE(callbacks, bus->filter_callbacks, f);
                         free(f);
                         return 1;
                 }
@@ -2366,94 +2428,387 @@ int sd_bus_remove_filter(sd_bus *bus, sd_message_handler_t callback, void *userd
         return 0;
 }
 
-static int bus_add_object(
-                sd_bus *bus,
-                bool fallback,
-                const char *path,
-                sd_message_handler_t callback,
-                void *userdata) {
+_public_ int sd_bus_add_match(sd_bus *bus,
+                              const char *match,
+                              sd_bus_message_handler_t callback,
+                              void *userdata) {
+
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+        uint64_t cookie = 0;
+        int r = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(match, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_match_parse(match, &components, &n_components);
+        if (r < 0)
+                goto finish;
+
+        if (bus->bus_client) {
+                cookie = ++bus->match_cookie;
+
+                r = bus_add_match_internal(bus, match, components, n_components, cookie);
+                if (r < 0)
+                        goto finish;
+        }
+
+        bus->match_callbacks_modified = true;
+        r = bus_match_add(&bus->match_callbacks, components, n_components, callback, userdata, cookie, NULL);
+        if (r < 0) {
+                if (bus->bus_client)
+                        bus_remove_match_internal(bus, match, cookie);
+        }
+
+finish:
+        bus_match_parse_free(components, n_components);
+        return r;
+}
+
+_public_ int sd_bus_remove_match(sd_bus *bus,
+                                 const char *match,
+                                 sd_bus_message_handler_t callback,
+                                 void *userdata) {
+
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+        int r = 0, q = 0;
+        uint64_t cookie = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(match, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_match_parse(match, &components, &n_components);
+        if (r < 0)
+                return r;
+
+        bus->match_callbacks_modified = true;
+        r = bus_match_remove(&bus->match_callbacks, components, n_components, callback, userdata, &cookie);
+
+        if (bus->bus_client)
+                q = bus_remove_match_internal(bus, match, cookie);
+
+        bus_match_parse_free(components, n_components);
+
+        return r < 0 ? r : q;
+}
 
-        struct object_callback *c;
+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();
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_bus *bus = userdata;
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (!path)
-                return -EINVAL;
-        if (!callback)
-                return -EINVAL;
+        assert(bus);
 
-        r = hashmap_ensure_allocated(&bus->object_callbacks, string_hash_func, string_compare_func);
+        r = sd_bus_process(bus, NULL);
         if (r < 0)
                 return r;
 
-        c = new(struct object_callback, 1);
-        if (!c)
-                return -ENOMEM;
+        return 1;
+}
 
-        c->path = strdup(path);
-        if (!path) {
-                free(c);
-                return -ENOMEM;
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_bus *bus = userdata;
+        int r;
+
+        assert(bus);
+
+        r = sd_bus_process(bus, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_bus *bus = userdata;
+        int r, e;
+        usec_t until;
+
+        assert(s);
+        assert(bus);
+
+        e = sd_bus_get_events(bus);
+        if (e < 0)
+                return e;
+
+        if (bus->output_fd != bus->input_fd) {
+
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e & POLLIN);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_io_events(bus->output_io_event_source, e & POLLOUT);
+                if (r < 0)
+                        return r;
+        } else {
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e);
+                if (r < 0)
+                        return r;
         }
 
-        c->callback = callback;
-        c->userdata = userdata;
-        c->is_fallback = fallback;
+        r = sd_bus_get_timeout(bus, &until);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                int j;
 
-        r = hashmap_put(bus->object_callbacks, c->path, c);
-        if (r < 0) {
-                free(c->path);
-                free(c);
+                j = sd_event_source_set_time(bus->time_event_source, until);
+                if (j < 0)
+                        return j;
+        }
+
+        r = sd_event_source_set_enabled(bus->time_event_source, r > 0);
+        if (r < 0)
                 return r;
+
+        return 1;
+}
+
+static int quit_callback(sd_event_source *event, void *userdata) {
+        sd_bus *bus = userdata;
+
+        assert(event);
+
+        sd_bus_flush(bus);
+
+        return 1;
+}
+
+_public_ int sd_bus_attach_event(sd_bus *bus, sd_event *event, int priority) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        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;
         }
 
+        r = sd_event_add_io(bus->event, bus->input_fd, 0, io_callback, bus, &bus->input_io_event_source);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(bus->input_io_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        if (bus->output_fd != bus->input_fd) {
+                r = sd_event_add_io(bus->event, bus->output_fd, 0, io_callback, bus, &bus->output_io_event_source);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_event_source_set_priority(bus->output_io_event_source, priority);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = sd_event_source_set_prepare(bus->input_io_event_source, prepare_callback);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_monotonic(bus->event, 0, 0, time_callback, bus, &bus->time_event_source);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(bus->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_quit(bus->event, quit_callback, bus, &bus->quit_event_source);
+        if (r < 0)
+                goto fail;
+
         return 0;
+
+fail:
+        sd_bus_detach_event(bus);
+        return r;
 }
 
-static int bus_remove_object(
-                sd_bus *bus,
-                bool fallback,
-                const char *path,
-                sd_message_handler_t callback,
-                void *userdata) {
+_public_ int sd_bus_detach_event(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus->event, -ENXIO);
 
-        struct object_callback *c;
+        if (bus->input_io_event_source) {
+                sd_event_source_set_enabled(bus->input_io_event_source, SD_EVENT_OFF);
+                bus->input_io_event_source = sd_event_source_unref(bus->input_io_event_source);
+        }
 
-        if (!bus)
-                return -EINVAL;
-        if (!path)
-                return -EINVAL;
-        if (!callback)
-                return -EINVAL;
+        if (bus->output_io_event_source) {
+                sd_event_source_set_enabled(bus->output_io_event_source, SD_EVENT_OFF);
+                bus->output_io_event_source = sd_event_source_unref(bus->output_io_event_source);
+        }
 
-        c = hashmap_get(bus->object_callbacks, path);
-        if (!c)
-                return 0;
+        if (bus->time_event_source) {
+                sd_event_source_set_enabled(bus->time_event_source, SD_EVENT_OFF);
+                bus->time_event_source = sd_event_source_unref(bus->time_event_source);
+        }
+
+        if (bus->quit_event_source) {
+                sd_event_source_set_enabled(bus->quit_event_source, SD_EVENT_OFF);
+                bus->quit_event_source = sd_event_source_unref(bus->quit_event_source);
+        }
+
+        if (bus->event)
+                bus->event = sd_event_unref(bus->event);
+
+        return 0;
+}
+
+_public_ sd_event* sd_bus_get_event(sd_bus *bus) {
+        assert_return(bus, NULL);
+
+        return bus->event;
+}
+
+_public_ sd_bus_message* sd_bus_get_current(sd_bus *bus) {
+        assert_return(bus, NULL);
+
+        return bus->current;
+}
+
+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 (c->callback != callback || c->userdata != userdata || c->is_fallback != fallback)
+        if (*default_bus) {
+                *ret = sd_bus_ref(*default_bus);
                 return 0;
+        }
 
-        assert_se(c == hashmap_remove(bus->object_callbacks, c->path));
+        r = bus_open(&b);
+        if (r < 0)
+                return r;
 
-        free(c->path);
-        free(c);
+        b->default_bus_ptr = default_bus;
+        b->tid = gettid();
+        *default_bus = b;
 
+        *ret = b;
         return 1;
 }
 
-int sd_bus_add_object(sd_bus *bus, const char *path, sd_message_handler_t callback, void *userdata) {
-        return bus_add_object(bus, false, path, callback, userdata);
+_public_ int sd_bus_default_system(sd_bus **ret) {
+        static __thread sd_bus *default_system_bus = NULL;
+
+        return bus_default(sd_bus_open_system, &default_system_bus, ret);
 }
 
-int sd_bus_remove_object(sd_bus *bus, const char *path, sd_message_handler_t callback, void *userdata) {
-        return bus_remove_object(bus, false, path, callback, userdata);
+_public_ int sd_bus_default_user(sd_bus **ret) {
+        static __thread sd_bus *default_user_bus = NULL;
+
+        return bus_default(sd_bus_open_user, &default_user_bus, ret);
 }
 
-int sd_bus_add_fallback(sd_bus *bus, const char *prefix, sd_message_handler_t callback, void *userdata) {
-        return bus_add_object(bus, true, prefix, callback, userdata);
+_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_ char *sd_bus_label_escape(const char *s) {
+        char *r, *t;
+        const char *f;
+
+        assert_return(s, NULL);
+
+        /* Escapes all chars that D-Bus' object path cannot deal
+         * with. Can be reversed with bus_path_unescape(). We special
+         * case the empty string. */
+
+        if (*s == 0)
+                return strdup("_");
+
+        r = new(char, strlen(s)*3 + 1);
+        if (!r)
+                return NULL;
+
+        for (f = s, t = r; *f; f++) {
+
+                /* Escape everything that is not a-zA-Z0-9. We also
+                 * escape 0-9 if it's the first character */
+
+                if (!(*f >= 'A' && *f <= 'Z') &&
+                    !(*f >= 'a' && *f <= 'z') &&
+                    !(f > s && *f >= '0' && *f <= '9')) {
+                        *(t++) = '_';
+                        *(t++) = hexchar(*f >> 4);
+                        *(t++) = hexchar(*f);
+                } else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+
+        return r;
 }
 
-int sd_bus_remove_fallback(sd_bus *bus, const char *prefix, sd_message_handler_t callback, void *userdata) {
-        return bus_remove_object(bus, true, prefix, callback, userdata);
+_public_ char *sd_bus_label_unescape(const char *f) {
+        char *r, *t;
+
+        assert_return(f, NULL);
+
+        /* Special case for the empty string */
+        if (streq(f, "_"))
+                return strdup("");
+
+        r = new(char, strlen(f) + 1);
+        if (!r)
+                return NULL;
+
+        for (t = r; *f; f++) {
+
+                if (*f == '_') {
+                        int a, b;
+
+                        if ((a = unhexchar(f[1])) < 0 ||
+                            (b = unhexchar(f[2])) < 0) {
+                                /* Invalid escape code, let's take it literal then */
+                                *(t++) = '_';
+                        } else {
+                                *(t++) = (char) ((a << 4) | b);
+                                f += 2;
+                        }
+                } else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+
+        return r;
 }