chiark / gitweb /
bus: keep kernel bus fd around during entire life-time of bus
[elogind.git] / src / libsystemd-bus / sd-bus.c
index 70288ee1310378858b4aaa75982bc2711ec5f9bd..08ab202baf8301b1eca4c280d2fa52a1e5ba802a 100644 (file)
 
 #include "util.h"
 #include "macro.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"
 
-#define WQUEUE_MAX 128
+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_free(sd_bus *b) {
         struct filter_callback *f;
+        struct object_callback *c;
+        unsigned i;
 
         assert(b);
 
-        if (b->fd >= 0)
-                close_nointr_nofail(b->fd);
+        bus_close_fds(b);
 
         free(b->rbuffer);
+        free(b->unique_name);
+        free(b->auth_buffer);
+        free(b->address);
+        free(b->kernel);
+
+        free(b->exec_path);
+        strv_free(b->exec_argv);
+
+        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);
-        free(b->unique_name);
 
         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);
                 free(f);
         }
 
+        while ((c = hashmap_steal_first(b->object_callbacks))) {
+                free(c->path);
+                free(c);
+        }
+
+        hashmap_free(b->object_callbacks);
+        bus_match_free(&b->match_callbacks);
+
+        bus_kernel_flush_memfd(b);
+
         free(b);
 }
 
-static sd_bus* bus_new(void) {
+int sd_bus_new(sd_bus **ret) {
         sd_bus *r;
 
+        if (!ret)
+                return -EINVAL;
+
         r = new0(sd_bus, 1);
         if (!r)
-                return NULL;
+                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;
 
         /* We guarantee that wqueue always has space for at least one
          * entry */
         r->wqueue = new(sd_bus_message*, 1);
         if (!r->wqueue) {
                 free(r);
-                return NULL;
+                return -ENOMEM;
         }
 
-        return r;
-};
+        *ret = r;
+        return 0;
+}
+
+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;
+
+        a = strdup(address);
+        if (!a)
+                return -ENOMEM;
+
+        free(bus->address);
+        bus->address = a;
+
+        return 0;
+}
+
+int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd) {
+        if (!bus)
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
+        if (input_fd < 0)
+                return -EINVAL;
+        if (output_fd < 0)
+                return -EINVAL;
+
+        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[]) {
+        char *p, **a;
+
+        if (!bus)
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
+        if (!path)
+                return -EINVAL;
+        if (strv_isempty(argv))
+                return -EINVAL;
+
+        p = strdup(path);
+        if (!p)
+                return -ENOMEM;
+
+        a = strv_copy(argv);
+        if (!a) {
+                free(p);
+                return -ENOMEM;
+        }
+
+        free(bus->exec_path);
+        strv_free(bus->exec_argv);
+
+        bus->exec_path = p;
+        bus->exec_argv = a;
+
+        return 0;
+}
+
+int sd_bus_set_bus_client(sd_bus *bus, int b) {
+        if (!bus)
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
+
+        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;
+
+        bus->negotiate_fds = !!b;
+        return 0;
+}
+
+int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
+        if (!bus)
+                return -EINVAL;
+        if (!b && !sd_id128_equal(server_id, SD_ID128_NULL))
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
+
+        bus->is_server = !!b;
+        bus->server_id = server_id;
+        return 0;
+}
+
+int sd_bus_set_anonymous(sd_bus *bus, int b) {
+        if (!bus)
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
+
+        bus->anonymous_auth = !!b;
+        return 0;
+}
 
 static int hello_callback(sd_bus *bus, sd_bus_message *reply, void *userdata) {
         const char *s;
         int r;
 
         assert(bus);
+        assert(bus->state == BUS_HELLO);
         assert(reply);
 
-        bus->state = BUS_RUNNING;
+        r = bus_message_to_errno(reply);
+        if (r < 0)
+                return r;
 
         r = sd_bus_message_read(reply, "s", &s);
         if (r < 0)
                 return r;
 
+        if (!service_name_is_valid(s) || s[0] != ':')
+                return -EBADMSG;
+
         bus->unique_name = strdup(s);
         if (!bus->unique_name)
                 return -ENOMEM;
 
+        bus->state = BUS_RUNNING;
+
         return 1;
 }
 
@@ -108,6 +275,9 @@ static int bus_send_hello(sd_bus *bus) {
 
         assert(bus);
 
+        if (!bus->bus_client || bus->is_kernel)
+                return 0;
+
         r = sd_bus_message_new_method_call(
                         bus,
                         "org.freedesktop.DBus",
@@ -118,29 +288,19 @@ static int bus_send_hello(sd_bus *bus) {
         if (r < 0)
                 return r;
 
-        r = sd_bus_send_with_reply(bus, m, hello_callback, NULL, (uint64_t) -1, NULL);
-        if (r < 0)
-                return r;
-
-        return 0;
+        return sd_bus_send_with_reply(bus, m, hello_callback, NULL, 0, &bus->hello_serial);
 }
 
-static int bus_start_running(sd_bus *bus) {
-        int r;
-
+int bus_start_running(sd_bus *bus) {
         assert(bus);
 
-        if (bus->send_hello) {
+        if (bus->bus_client && !bus->is_kernel) {
                 bus->state = BUS_HELLO;
-
-                r = bus_send_hello(bus);
-                if (r < 0)
-                        return r;
+                return 1;
         }
 
         bus->state = BUS_RUNNING;
-
-        return 0;
+        return 1;
 }
 
 static int parse_address_key(const char **p, const char *key, char **value) {
@@ -150,21 +310,24 @@ static int parse_address_key(const char **p, const char *key, char **value) {
 
         assert(p);
         assert(*p);
-        assert(key);
         assert(value);
 
-        l = strlen(key);
-        if (!strncmp(*p, key, l) != 0)
-                return 0;
+        if (key) {
+                l = strlen(key);
+                if (strncmp(*p, key, l) != 0)
+                        return 0;
 
-        if ((*p)[l] != '=')
-                return 0;
+                if ((*p)[l] != '=')
+                        return 0;
 
-        if (*value)
-                return -EINVAL;
+                if (*value)
+                        return -EINVAL;
+
+                a = *p + l + 1;
+        } else
+                a = *p;
 
-        a = *p + l + 1;
-        while (*a != ';' && *a != 0) {
+        while (*a != ';' && *a != ',' && *a != 0) {
                 char c, *t;
 
                 if (*a == '%') {
@@ -182,12 +345,14 @@ static int parse_address_key(const char **p, const char *key, char **value) {
                                 return y;
                         }
 
-                        a += 3;
                         c = (char) ((x << 4) | y);
-                } else
+                        a += 3;
+                } else {
                         c = *a;
+                        a++;
+                }
 
-                t = realloc(r, n + 1);
+                t = realloc(r, n + 2);
                 if (!t) {
                         free(r);
                         return -ENOMEM;
@@ -197,8 +362,21 @@ static int parse_address_key(const char **p, const char *key, char **value) {
                 r[n++] = c;
         }
 
+        if (!r) {
+                r = strdup("");
+                if (!r)
+                        return -ENOMEM;
+        } else
+                r[n] = 0;
+
+        if (*a == ',')
+                a++;
+
         *p = a;
+
+        free(*value);
         *value = r;
+
         return 1;
 }
 
@@ -206,517 +384,577 @@ static void skip_address_key(const char **p) {
         assert(p);
         assert(*p);
 
-        *p += strcspn(*p, ";");
+        *p += strcspn(*p, ",");
+
+        if (**p == ',')
+                (*p) ++;
 }
 
-static int bus_parse_next_address(sd_bus *b) {
-        const char *a, *p;
-        _cleanup_free_ char *guid = NULL;
+static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *path = NULL, *abstract = NULL;
+        size_t l;
         int r;
 
         assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
 
-        if (!b->address)
-                return 0;
-        if (b->address[b->address_index] == 0)
-                return 0;
+        while (**p != 0 && **p != ';') {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-        a = b->address + b->address_index;
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-        zero(b->sockaddr);
-        b->sockaddr_size = 0;
-        b->peer = SD_ID128_NULL;
+                r = parse_address_key(p, "abstract", &abstract);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-        if (startswith(a, "unix:")) {
-                _cleanup_free_ char *path = NULL, *abstract = NULL;
+                skip_address_key(p);
+        }
 
-                p = a + 5;
-                while (*p != 0 && *p != ';') {
-                        r = parse_address_key(&p, "guid", &guid);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        if (!path && !abstract)
+                return -EINVAL;
 
-                        r = parse_address_key(&p, "path", &path);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        if (path && abstract)
+                return -EINVAL;
 
-                        r = parse_address_key(&p, "abstract", &abstract);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        if (path) {
+                l = strlen(path);
+                if (l > sizeof(b->sockaddr.un.sun_path))
+                        return -E2BIG;
+
+                b->sockaddr.un.sun_family = AF_UNIX;
+                strncpy(b->sockaddr.un.sun_path, path, sizeof(b->sockaddr.un.sun_path));
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l;
+        } else if (abstract) {
+                l = strlen(abstract);
+                if (l > sizeof(b->sockaddr.un.sun_path) - 1)
+                        return -E2BIG;
+
+                b->sockaddr.un.sun_family = AF_UNIX;
+                b->sockaddr.un.sun_path[0] = 0;
+                strncpy(b->sockaddr.un.sun_path+1, abstract, sizeof(b->sockaddr.un.sun_path)-1);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
+        }
 
-                        skip_address_key(&p);
-                }
+        return 0;
+}
 
-                if (!path && !abstract)
-                        return -EINVAL;
+static int parse_tcp_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
+        int r;
+        struct addrinfo *result, hints = {
+                .ai_socktype = SOCK_STREAM,
+                .ai_flags = AI_ADDRCONFIG,
+        };
 
-                if (path && abstract)
-                        return -EINVAL;
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
 
-                if (path) {
-                        size_t l;
+        while (**p != 0 && **p != ';') {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-                        l = strlen(path);
-                        if (l > sizeof(b->sockaddr.un.sun_path))
-                                return -E2BIG;
+                r = parse_address_key(p, "host", &host);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-                        b->sockaddr.un.sun_family = AF_UNIX;
-                        strncpy(b->sockaddr.un.sun_path, path, sizeof(b->sockaddr.un.sun_path));
-                        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l;
-                } else if (abstract) {
-                        size_t l;
+                r = parse_address_key(p, "port", &port);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-                        l = strlen(path);
-                        if (l > sizeof(b->sockaddr.un.sun_path) - 1)
-                                return -E2BIG;
+                r = parse_address_key(p, "family", &family);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-                        b->sockaddr.un.sun_family = AF_UNIX;
-                        b->sockaddr.un.sun_path[0] = 0;
-                        strncpy(b->sockaddr.un.sun_path+1, path, sizeof(b->sockaddr.un.sun_path)-1);
-                        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
-                }
+                skip_address_key(p);
+        }
 
-        } else if (startswith(a, "tcp:")) {
-                _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
-                struct addrinfo hints, *result;
+        if (!host || !port)
+                return -EINVAL;
 
-                p = a + 4;
-                while (*p != 0 && *p != ';') {
-                        r = parse_address_key(&p, "guid", &guid);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        if (family) {
+                if (streq(family, "ipv4"))
+                        hints.ai_family = AF_INET;
+                else if (streq(family, "ipv6"))
+                        hints.ai_family = AF_INET6;
+                else
+                        return -EINVAL;
+        }
 
-                        r = parse_address_key(&p, "host", &host);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        r = getaddrinfo(host, port, &hints, &result);
+        if (r == EAI_SYSTEM)
+                return -errno;
+        else if (r != 0)
+                return -EADDRNOTAVAIL;
 
-                        r = parse_address_key(&p, "port", &port);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        memcpy(&b->sockaddr, result->ai_addr, result->ai_addrlen);
+        b->sockaddr_size = result->ai_addrlen;
 
-                        r = parse_address_key(&p, "family", &family);
-                        if (r < 0)
-                                return r;
-                        else if (r > 0)
-                                continue;
+        freeaddrinfo(result);
 
-                        skip_address_key(&p);
-                }
+        return 0;
+}
 
-                if (!host || !port)
-                        return -EINVAL;
+static int parse_exec_address(sd_bus *b, const char **p, char **guid) {
+        char *path = NULL;
+        unsigned n_argv = 0, j;
+        char **argv = NULL;
+        int r;
 
-                zero(hints);
-                hints.ai_socktype = SOCK_STREAM;
-                hints.ai_flags = AI_ADDRCONFIG;
-
-                if (family) {
-                        if (streq(family, "ipv4"))
-                                hints.ai_family = AF_INET;
-                        else if (streq(family, "ipv6"))
-                                hints.ai_family = AF_INET6;
-                        else
-                                return -EINVAL;
-                }
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
 
-                r = getaddrinfo(host, port, &hints, &result);
-                if (r == EAI_SYSTEM)
-                        return -errno;
-                else if (r != 0)
-                        return -EADDRNOTAVAIL;
+        while (**p != 0 && **p != ';') {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
 
-                memcpy(&b->sockaddr, result->ai_addr, result->ai_addrlen);
-                b->sockaddr_size = result->ai_addrlen;
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
 
-                freeaddrinfo(result);
-        }
+                if (startswith(*p, "argv")) {
+                        unsigned ul;
 
-        if (guid) {
-                r = sd_id128_from_string(guid, &b->peer);
-                if (r < 0)
-                        return r;
-        }
+                        errno = 0;
+                        ul = strtoul(*p + 4, (char**) p, 10);
+                        if (errno > 0 || **p != '=' || ul > 256) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
 
-        b->address_index = p - b->address;
-        return 1;
-}
+                        (*p) ++;
 
-static void iovec_advance(struct iovec *iov, unsigned *idx, size_t size) {
+                        if (ul >= n_argv) {
+                                char **x;
 
-        while (size > 0) {
-                struct iovec *i = iov + *idx;
+                                x = realloc(argv, sizeof(char*) * (ul + 2));
+                                if (!x) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
 
-                if (i->iov_len > size) {
-                        i->iov_base = (uint8_t*) i->iov_base + size;
-                        i->iov_len -= size;
-                        return;
-                }
+                                memset(x + n_argv, 0, sizeof(char*) * (ul - n_argv + 2));
 
-                size -= i->iov_len;
+                                argv = x;
+                                n_argv = ul + 1;
+                        }
 
-                i->iov_base = NULL;
-                i->iov_len = 0;
+                        r = parse_address_key(p, NULL, argv + ul);
+                        if (r < 0)
+                                goto fail;
 
-                (*idx) ++;
-        }
-}
+                        continue;
+                }
 
-static int bus_write_auth(sd_bus *b) {
-        struct msghdr mh;
-        ssize_t k;
+                skip_address_key(p);
+        }
 
-        assert(b);
-        assert(b->state == BUS_AUTHENTICATING);
+        if (!path) {
+                r = -EINVAL;
+                goto fail;
+        }
 
-        if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
-                return 0;
+        /* Make sure there are no holes in the array, with the
+         * exception of argv[0] */
+        for (j = 1; j < n_argv; j++)
+                if (!argv[j]) {
+                        r = -EINVAL;
+                        goto fail;
+                }
 
-        zero(mh);
-        mh.msg_iov = b->auth_iovec + b->auth_index;
-        mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
+        if (argv && argv[0] == NULL) {
+                argv[0] = strdup(path);
+                if (!argv[0]) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
 
-        k = sendmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
+        b->exec_path = path;
+        b->exec_argv = argv;
+        return 0;
 
-        iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
+fail:
+        for (j = 0; j < n_argv; j++)
+                free(argv[j]);
 
-        return 1;
+        free(argv);
+        free(path);
+        return r;
 }
 
-static int bus_auth_verify(sd_bus *b) {
-        char *e, *f;
-        sd_id128_t peer;
-        unsigned i;
+static int parse_kernel_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *path = NULL;
         int r;
 
-        /* We expect two response lines: "OK", "AGREE_UNIX_FD", and
-         * that's it */
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
 
-        e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2);
-        if (!e)
-                return 0;
+        while (**p != 0 && **p != ';') {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-        f = memmem(e, b->rbuffer_size - (e - (char*) b->rbuffer), "\r\n", 2);
-        if (!f)
-                return 0;
-
-        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 + 2]);
-
-                if (x < 0 || y < 0)
-                        return -EINVAL;
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
 
-                peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
+                skip_address_key(p);
         }
 
-        if (!sd_id128_equal(b->peer, SD_ID128_NULL) &&
-            !sd_id128_equal(b->peer, peer))
-                return -EPERM;
-
-        b->peer = peer;
+        if (!path)
+                return -EINVAL;
 
-        b->can_fds =
-                (f - e == sizeof("\r\nAGREE_UNIX_FD") - 1) &&
-                memcmp(e + 2, "AGREE_UNIX_FD", sizeof("AGREE_UNIX_FD") - 1) == 0;
+        free(b->kernel);
+        b->kernel = path;
+        path = NULL;
 
-        if (f + 2 > (char*) b->rbuffer + b->rbuffer_size) {
-                b->rbuffer_size -= (f - (char*) b->rbuffer);
-                memmove(b->rbuffer, f + 2, b->rbuffer_size);
-        }
+        return 0;
+}
 
-        r = bus_start_running(b);
-        if (r < 0)
-                return r;
+static void bus_reset_parsed_address(sd_bus *b) {
+        assert(b);
 
-        return 1;
+        zero(b->sockaddr);
+        b->sockaddr_size = 0;
+        strv_free(b->exec_argv);
+        free(b->exec_path);
+        b->exec_path = NULL;
+        b->exec_argv = NULL;
+        b->server_id = SD_ID128_NULL;
+        free(b->kernel);
+        b->kernel = NULL;
 }
 
-static int bus_read_auth(sd_bus *b) {
-        struct msghdr mh;
-        struct iovec iov;
-        size_t n;
-        ssize_t k;
+static int bus_parse_next_address(sd_bus *b) {
+        _cleanup_free_ char *guid = NULL;
+        const char *a;
         int r;
 
         assert(b);
 
-        r = bus_auth_verify(b);
-        if (r != 0)
-                return r;
+        if (!b->address)
+                return 0;
+        if (b->address[b->address_index] == 0)
+                return 0;
 
-        n = MAX(3 + 32 + 2 + sizeof("AGREE_UNIX_FD") - 1 + 2, b->rbuffer_size * 2);
+        bus_reset_parsed_address(b);
 
-        zero(iov);
-        iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
-        iov.iov_len = n - b->rbuffer_size;
+        a = b->address + b->address_index;
 
-        zero(mh);
-        mh.msg_iov = &iov;
-        mh.msg_iovlen = 1;
+        while (*a != 0) {
 
-        k = recvmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
+                if (*a == ';') {
+                        a++;
+                        continue;
+                }
 
-        b->rbuffer_size += k;
+                if (startswith(a, "unix:")) {
+                        a += 5;
 
-        r = bus_auth_verify(b);
-        if (r != 0)
-                return r;
+                        r = parse_unix_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+                        break;
 
-        return 0;
-}
+                } else if (startswith(a, "tcp:")) {
 
-static int bus_start_auth(sd_bus *b) {
-        static const char auth_prefix[] = "\0AUTH_EXTERNAL ";
-        static const char auth_suffix[] = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
+                        a += 4;
+                        r = parse_tcp_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
 
-        char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
-        size_t l;
+                        break;
 
-        assert(b);
+                } else if (startswith(a, "unixexec:")) {
+
+                        a += 9;
+                        r = parse_exec_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
 
-        b->state = BUS_AUTHENTICATING;
+                        break;
 
-        snprintf(text, sizeof(text), "%llu", (unsigned long long) geteuid());
-        char_array_0(text);
+                } else if (startswith(a, "kernel:")) {
 
-        l = strlen(text);
-        b->auth_uid = hexmem(text, l);
-        if (!b->auth_uid)
-                return -ENOMEM;
+                        a += 7;
+                        r = parse_kernel_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
 
-        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 = sizeof(auth_suffix) -1;
-        b->auth_size = sizeof(auth_prefix) - 1 + l * 2 + sizeof(auth_suffix) - 1;
+                        break;
+                }
+
+                a = strchr(a, ';');
+                if (!a)
+                        return 0;
+        }
+
+        if (guid) {
+                r = sd_id128_from_string(guid, &b->server_id);
+                if (r < 0)
+                        return r;
+        }
 
-        return bus_write_auth(b);
+        b->address_index = a - b->address;
+        return 1;
 }
 
-static int bus_start_connect(sd_bus *b) {
+static int bus_start_address(sd_bus *b) {
         int r;
 
         assert(b);
-        assert(b->fd < 0);
 
         for (;;) {
-                if (b->sockaddr.sa.sa_family == AF_UNSPEC) {
-                        r = bus_parse_next_address(b);
-                        if (r < 0)
+                sd_bus_close(b);
+
+                if (b->sockaddr.sa.sa_family != AF_UNSPEC) {
+
+                        r = bus_socket_connect(b);
+                        if (r >= 0)
                                 return r;
-                        if (r == 0)
-                                return b->last_connect_error ? b->last_connect_error : -ECONNREFUSED;
-                }
 
-                b->fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
-                if (b->fd < 0) {
-                        b->last_connect_error = -errno;
-                        zero(b->sockaddr);
-                        continue;
-                }
+                        b->last_connect_error = -r;
 
-                r = connect(b->fd, &b->sockaddr.sa, b->sockaddr_size);
-                if (r < 0) {
-                        if (errno == EINPROGRESS)
-                                return 0;
+                } else if (b->exec_path) {
 
-                        b->last_connect_error = -errno;
-                        close_nointr_nofail(b->fd);
-                        b->fd = -1;
-                        zero(b->sockaddr);
-                        continue;
-                }
+                        r = bus_socket_exec(b);
+                        if (r >= 0)
+                                return r;
 
-                return bus_start_auth(b);
-        }
-}
+                        b->last_connect_error = -r;
+                } else if (b->kernel) {
 
-int sd_bus_open_system(sd_bus **ret) {
-        const char *e;
-        sd_bus *b;
-        int r;
+                        r = bus_kernel_connect(b);
+                        if (r >= 0)
+                                return r;
 
-        if (!ret)
-                return -EINVAL;
+                        b->last_connect_error = -r;
+                }
 
-        e = getenv("DBUS_SYSTEM_BUS_ADDRESS");
-        if (e) {
-                r = sd_bus_open_address(e, &b);
+                r = bus_parse_next_address(b);
                 if (r < 0)
                         return r;
-
-                b->send_hello = true;
-                *ret = b;
-                return r;
+                if (r == 0)
+                        return b->last_connect_error ? -b->last_connect_error : -ECONNREFUSED;
         }
+}
 
-        b = bus_new();
-        if (!b)
-                return -ENOMEM;
-
-        b->send_hello = true;
-
-        b->sockaddr.un.sun_family = AF_UNIX;
-        strncpy(b->sockaddr.un.sun_path, "/run/dbus/system_bus_socket", sizeof(b->sockaddr.un.sun_path));
-        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + sizeof("/run/dbus/system_bus_socket") - 1;
-
-        r = bus_start_connect(b);
-        if (r < 0) {
-                bus_free(b);
-                return r;
-        }
+int bus_next_address(sd_bus *b) {
+        assert(b);
 
-        *ret = b;
-        return 0;
+        bus_reset_parsed_address(b);
+        return bus_start_address(b);
 }
 
-int sd_bus_open_user(sd_bus **ret) {
-        const char *e;
-        sd_bus *b;
-        size_t l;
+static int bus_start_fd(sd_bus *b) {
+        struct stat st;
         int r;
 
-        if (!ret)
-                return -EINVAL;
+        assert(b);
+        assert(b->input_fd >= 0);
+        assert(b->output_fd >= 0);
 
-        e = getenv("DBUS_SESSION_BUS_ADDRESS");
-        if (e) {
-                r = sd_bus_open_address(e, &b);
+        r = fd_nonblock(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        r = fd_cloexec(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        if (b->input_fd != b->output_fd) {
+                r = fd_nonblock(b->output_fd, true);
                 if (r < 0)
                         return r;
 
-                b->send_hello = true;
-                *ret = b;
-                return r;
+                r = fd_cloexec(b->output_fd, true);
+                if (r < 0)
+                        return r;
         }
 
-        e = getenv("XDG_RUNTIME_DIR");
-        if (!e)
-                return -ENOENT;
+        if (fstat(b->input_fd, &st) < 0)
+                return -errno;
+
+        if (S_ISCHR(b->input_fd))
+                return bus_kernel_take_fd(b);
+        else
+                return bus_socket_take_fd(b);
+}
 
-        l = strlen(e);
-        if (l + 4 > sizeof(b->sockaddr.un.sun_path))
-                return -E2BIG;
+int sd_bus_start(sd_bus *bus) {
+        int r;
 
-        b = bus_new();
-        if (!b)
-                return -ENOMEM;
+        if (!bus)
+                return -EINVAL;
+        if (bus->state != BUS_UNSET)
+                return -EPERM;
 
-        b->send_hello = true;
+        bus->state = BUS_OPENING;
 
-        b->sockaddr.un.sun_family = AF_UNIX;
-        memcpy(mempcpy(b->sockaddr.un.sun_path, e, l), "/bus", 4);
-        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l + 4;
+        if (bus->is_server && bus->bus_client)
+                return -EINVAL;
 
-        r = bus_start_connect(b);
-        if (r < 0) {
-                bus_free(b);
+        if (bus->input_fd >= 0)
+                r = bus_start_fd(bus);
+        else if (bus->address || bus->sockaddr.sa.sa_family != AF_UNSPEC || bus->exec_path || bus->kernel)
+                r = bus_start_address(bus);
+        else
+                return -EINVAL;
+
+        if (r < 0)
                 return r;
-        }
 
-        *ret = b;
-        return 0;
+        return bus_send_hello(bus);
 }
 
-int sd_bus_open_address(const char *address, sd_bus **ret) {
+int sd_bus_open_system(sd_bus **ret) {
+        const char *e;
         sd_bus *b;
         int r;
 
-        if (!address)
-                return -EINVAL;
         if (!ret)
                 return -EINVAL;
 
-        b = bus_new();
-        if (!b)
-                return -ENOMEM;
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
 
-        b->address = strdup(address);
-        if (!b->address) {
-                bus_free(b);
-                return -ENOMEM;
+        e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
+        if (e) {
+                r = sd_bus_set_address(b, e);
+                if (r < 0)
+                        goto fail;
+        } else {
+                b->sockaddr.un.sun_family = AF_UNIX;
+                strncpy(b->sockaddr.un.sun_path, "/run/dbus/system_bus_socket", sizeof(b->sockaddr.un.sun_path));
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + sizeof("/run/dbus/system_bus_socket") - 1;
         }
 
-        r = bus_start_connect(b);
-        if (r < 0) {
-                bus_free(b);
-                return r;
-        }
+        b->bus_client = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                goto fail;
 
         *ret = b;
         return 0;
+
+fail:
+        bus_free(b);
+        return r;
 }
 
-int sd_bus_open_fd(int fd, sd_bus **ret) {
+int sd_bus_open_user(sd_bus **ret) {
+        const char *e;
         sd_bus *b;
+        size_t l;
         int r;
 
-        if (fd < 0)
-                return -EINVAL;
         if (!ret)
                 return -EINVAL;
 
-        b = bus_new();
-        if (!b)
-                return -ENOMEM;
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        e = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
+        if (e) {
+                r = sd_bus_set_address(b, e);
+                if (r < 0)
+                        goto fail;
+        } else {
+                e = secure_getenv("XDG_RUNTIME_DIR");
+                if (!e) {
+                        r = -ENOENT;
+                        goto fail;
+                }
 
-        b->fd = fd;
-        fd_nonblock(b->fd, true);
-        fd_cloexec(b->fd, true);
+                l = strlen(e);
+                if (l + 4 > sizeof(b->sockaddr.un.sun_path)) {
+                        r = -E2BIG;
+                        goto fail;
+                }
 
-        r = bus_start_auth(b);
-        if (r < 0) {
-                bus_free(b);
-                return r;
+                b->sockaddr.un.sun_family = AF_UNIX;
+                memcpy(mempcpy(b->sockaddr.un.sun_path, e, l), "/bus", 4);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l + 4;
         }
 
+        b->bus_client = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                goto fail;
+
         *ret = b;
         return 0;
+
+fail:
+        bus_free(b);
+        return r;
 }
 
 void sd_bus_close(sd_bus *bus) {
         if (!bus)
                 return;
-        if (bus->fd < 0)
+
+        if (bus->state != BUS_CLOSED)
                 return;
 
-        close_nointr_nofail(bus->fd);
-        bus->fd = -1;
+        bus->state = BUS_CLOSED;
+
+        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. */
 }
 
 sd_bus *sd_bus_ref(sd_bus *bus) {
         if (!bus)
                 return NULL;
 
-        assert(bus->n_ref > 0);
+        assert_se(REFCNT_INC(bus->n_ref) >= 2);
 
-        bus->n_ref++;
         return bus;
 }
 
@@ -724,267 +962,171 @@ sd_bus *sd_bus_unref(sd_bus *bus) {
         if (!bus)
                 return 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_running(sd_bus *bus) {
+int sd_bus_is_open(sd_bus *bus) {
         if (!bus)
                 return -EINVAL;
 
-        if (bus->fd < 0)
-                return -ENOTCONN;
-
-        return bus->state == BUS_RUNNING;
+        return BUS_IS_OPEN(bus->state);
 }
 
 int sd_bus_can_send(sd_bus *bus, char type) {
+        int r;
 
         if (!bus)
                 return -EINVAL;
+        if (bus->state == BUS_UNSET)
+                return -ENOTCONN;
+
+        if (type == SD_BUS_TYPE_UNIX_FD) {
+                if (!bus->negotiate_fds)
+                        return 0;
+
+                r = bus_ensure_running(bus);
+                if (r < 0)
+                        return r;
 
-        if (type == SD_BUS_TYPE_UNIX_FD)
                 return bus->can_fds;
+        }
 
         return bus_type_is_valid(type);
 }
 
+int sd_bus_get_server_id(sd_bus *bus, sd_id128_t *server_id) {
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!server_id)
+                return -EINVAL;
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        *server_id = bus->server_id;
+        return 0;
+}
+
 static int bus_seal_message(sd_bus *b, sd_bus_message *m) {
         assert(m);
 
+        if (m->header->version > b->message_version)
+                return -EPERM;
+
         if (m->sealed)
                 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 dispatch_wqueue(sd_bus *bus) {
+        int r, ret = 0;
 
         assert(bus);
-        assert(m);
-        assert(idx);
+        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
-        n = m->n_iovec * sizeof(struct iovec);
-        iov = alloca(n);
-        memcpy(iov, m->iovec, n);
+        while (bus->wqueue_size > 0) {
 
-        j = 0;
-        iovec_advance(iov, &j, *idx);
+                if (bus->is_kernel)
+                        r = bus_kernel_write_message(bus, bus->wqueue[0]);
+                else
+                        r = bus_socket_write_message(bus, bus->wqueue[0], &bus->windex);
 
-        zero(mh);
-        mh.msg_iov = iov;
-        mh.msg_iovlen = m->n_iovec;
+                if (r < 0) {
+                        sd_bus_close(bus);
+                        return r;
+                } else if (r == 0)
+                        /* Didn't do anything this time */
+                        return ret;
+                else if (bus->is_kernel || bus->windex >= BUS_MESSAGE_SIZE(bus->wqueue[0])) {
+                        /* Fully written. Let's drop the entry from
+                         * the queue.
+                         *
+                         * This isn't particularly optimized, but
+                         * well, this is supposed to be our worst-case
+                         * buffer only, and the socket buffer is
+                         * supposed to be our primary buffer, and if
+                         * it got full, then all bets are off
+                         * anyway. */
 
-        k = sendmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return -errno;
+                        sd_bus_message_unref(bus->wqueue[0]);
+                        bus->wqueue_size --;
+                        memmove(bus->wqueue, bus->wqueue + 1, sizeof(sd_bus_message*) * bus->wqueue_size);
+                        bus->windex = 0;
 
-        *idx += (size_t) k;
-        iovec_advance(iov, &j, *idx);
+                        ret = 1;
+                }
+        }
 
-        return j > m->n_iovec;
+        return ret;
 }
 
-static int message_read_need(sd_bus *bus, size_t *need) {
-        uint32_t a, b;
-        uint8_t e;
+static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
+        sd_bus_message *z = NULL;
+        int r, ret = 0;
 
         assert(bus);
-        assert(need);
+        assert(m);
+        assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
-        if (bus->rbuffer_size <= sizeof(struct bus_header)) {
-                *need = sizeof(struct bus_header);
-                return 0;
+        if (bus->rqueue_size > 0) {
+                /* Dispatch a queued message */
+
+                *m = bus->rqueue[0];
+                bus->rqueue_size --;
+                memmove(bus->rqueue, bus->rqueue + 1, sizeof(sd_bus_message*) * bus->rqueue_size);
+                return 1;
         }
 
-        a = ((const uint32_t*) bus->rbuffer)[1];
-        b = ((const uint32_t*) bus->rbuffer)[3];
+        /* Try to read a new message */
+        do {
+                if (bus->is_kernel)
+                        r = bus_kernel_read_message(bus, &z);
+                else
+                        r = bus_socket_read_message(bus, &z);
 
-        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 -EIO;
+                if (r < 0) {
+                        sd_bus_close(bus);
+                        return r;
+                }
+                if (r == 0)
+                        return ret;
 
-        *need = sizeof(struct bus_header) + ALIGN_TO(a, 8) + b;
-        return 0;
+                r = 1;
+        } while (!z);
+
+        *m = z;
+        return 1;
 }
 
-static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
-        sd_bus_message *t;
-        void *b = NULL;
+int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
         int r;
 
-        assert(bus);
-        assert(m);
-        assert(bus->rbuffer_size >= size);
+        if (!bus)
+                return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+        if (!m)
+                return -EINVAL;
 
-        if (bus->rbuffer_size > size) {
-                b = memdup((const uint8_t*) bus->rbuffer + size, bus->rbuffer_size - size);
-                if (!b) {
-                        free(t);
-                        return -ENOMEM;
-                }
+        if (m->n_fds > 0) {
+                r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ENOTSUP;
         }
 
-        r = bus_message_from_malloc(bus->rbuffer, size, &t);
-        if (r < 0) {
-                free(b);
-                return r;
-        }
-
-        bus->rbuffer = b;
-        bus->rbuffer_size -= size;
-
-        r = bus_message_parse(t);
-        if (r < 0) {
-                sd_bus_message_unref(t);
-                return r;
-        }
-
-        *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;
-
-        assert(bus);
-        assert(m);
-
-        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;
-
-        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;
-
-        k = recvmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
-        if (k < 0)
-                return errno == EAGAIN ? 0 : -errno;
-
-        bus->rbuffer_size += k;
-
-        r = message_read_need(bus, &need);
-        if (r < 0)
-                return r;
-
-        if (bus->rbuffer_size >= need)
-                return message_make(bus, need, m);
-
-        return 0;
-}
-
-static int dispatch_wqueue(sd_bus *bus) {
-        int r, c = 0;
-
-        assert(bus);
-
-        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);
-                        return r;
-                } else if (r == 0)
-                        /* Wasn't fully written yet... */
-                        break;
-                else {
-                        /* Fully written. Let's drop the entry from
-                         * the queue.
-                         *
-                         * This isn't particularly optimized, but
-                         * well, this is supposed to be our worst-case
-                         * buffer only, and the socket buffer is
-                         * supposed to be our primary buffer, and if
-                         * it got full, then all bets are off
-                         * anyway. */
-
-                        sd_bus_message_unref(bus->wqueue[0]);
-                        bus->wqueue_size --;
-                        memmove(bus->wqueue, bus->wqueue + 1, sizeof(sd_bus_message*) * bus->wqueue_size);
-                        bus->windex = 0;
-
-                        c++;
-                }
-        }
-
-        return c;
-}
-
-static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
-        int r;
-
-        assert(bus);
-        assert(m);
-
-        if (bus->fd < 0)
-                return -ENOTCONN;
-
-        if (bus->rqueue_size > 0) {
-                /* Dispatch a queued message */
-
-                *m = bus->rqueue[0];
-                bus->rqueue_size --;
-                memmove(bus->rqueue, bus->rqueue + 1, sizeof(sd_bus_message*) * bus->rqueue_size);
-                return 1;
-        }
-
-        /* Try to read a new message */
-        r = message_read(bus, m);
-        if (r < 0) {
-                sd_bus_close(bus);
-                return r;
-        }
-
-        return r;
-}
-
-int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
-        int r;
-
-        if (!bus)
-                return -EINVAL;
-        if (bus->fd < 0)
-                return -ENOTCONN;
-        if (!m)
-                return -EINVAL;
-        if (m->header->version > bus->message_version)
-                return -EPERM;
+        /* If the serial number isn't kept, then we know that no reply
+         * is expected */
+        if (!serial && !m->sealed)
+                m->header->flags |= SD_BUS_MESSAGE_NO_REPLY_EXPECTED;
 
         r = bus_seal_message(bus, m);
         if (r < 0)
@@ -995,14 +1137,18 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
         if (m->dont_send && !serial)
                 return 0;
 
-        if (bus->wqueue_size <= 0) {
+        if ((bus->state == BUS_RUNNING || bus->state == BUS_HELLO) && bus->wqueue_size <= 0) {
                 size_t idx = 0;
 
-                r = message_write(bus, m, &idx);
+                if (bus->is_kernel)
+                        r = bus_kernel_write_message(bus, m);
+                else
+                        r = bus_socket_write_message(bus, m, &idx);
+
                 if (r < 0) {
                         sd_bus_close(bus);
                         return r;
-                } else if (r == 0)  {
+                } 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
@@ -1017,7 +1163,7 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
 
                 /* Just append it to the queue. */
 
-                if (bus->wqueue_size >= WQUEUE_MAX)
+                if (bus->wqueue_size >= BUS_WQUEUE_MAX)
                         return -ENOBUFS;
 
                 q = realloc(bus->wqueue, sizeof(sd_bus_message*) * (bus->wqueue_size + 1));
@@ -1039,15 +1185,33 @@ static usec_t calc_elapse(uint64_t usec) {
                 return 0;
 
         if (usec == 0)
-                usec = SD_BUS_DEFAULT_TIMEOUT;
+                usec = BUS_DEFAULT_TIMEOUT;
 
         return now(CLOCK_MONOTONIC) + usec;
 }
 
+static int timeout_compare(const void *a, const void *b) {
+        const struct reply_callback *x = a, *y = b;
+
+        if (x->timeout != 0 && y->timeout == 0)
+                return -1;
+
+        if (x->timeout == 0 && y->timeout != 0)
+                return 1;
+
+        if (x->timeout < y->timeout)
+                return -1;
+
+        if (x->timeout > y->timeout)
+                return 1;
+
+        return 0;
+}
+
 int sd_bus_send_with_reply(
                 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) {
@@ -1057,20 +1221,32 @@ int sd_bus_send_with_reply(
 
         if (!bus)
                 return -EINVAL;
-        if (!bus->fd < 0)
+        if (!BUS_IS_OPEN(bus->state))
                 return -ENOTCONN;
         if (!m)
                 return -EINVAL;
         if (!callback)
                 return -EINVAL;
-        if (!m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
                 return -EINVAL;
+        if (m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return -EINVAL;
+
+        r = hashmap_ensure_allocated(&bus->reply_callbacks, uint64_hash_func, uint64_compare_func);
+        if (r < 0)
+                return r;
+
+        if (usec != (uint64_t) -1) {
+                r = prioq_ensure_allocated(&bus->reply_callbacks_prioq, timeout_compare);
+                if (r < 0)
+                        return r;
+        }
 
         r = bus_seal_message(bus, m);
         if (r < 0)
                 return r;
 
-        c = new(struct reply_callback, 1);
+        c = new0(struct reply_callback, 1);
         if (!c)
                 return -ENOMEM;
 
@@ -1085,10 +1261,18 @@ int sd_bus_send_with_reply(
                 return r;
         }
 
+        if (c->timeout != 0) {
+                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);
+                        return r;
+                }
+        }
+
         r = sd_bus_send(bus, m, serial);
         if (r < 0) {
-                hashmap_remove(bus->reply_callbacks, &c->serial);
-                free(c);
+                sd_bus_send_with_reply_cancel(bus, c->serial);
                 return r;
         }
 
@@ -1096,7 +1280,7 @@ int sd_bus_send_with_reply(
 }
 
 int sd_bus_send_with_reply_cancel(sd_bus *bus, uint64_t serial) {
-        struct reply_callbacks *c;
+        struct reply_callback *c;
 
         if (!bus)
                 return -EINVAL;
@@ -1107,10 +1291,38 @@ int sd_bus_send_with_reply_cancel(sd_bus *bus, uint64_t serial) {
         if (!c)
                 return 0;
 
+        if (c->timeout != 0)
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+
         free(c);
         return 1;
 }
 
+int bus_ensure_running(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->state == BUS_UNSET || bus->state == BUS_CLOSED)
+                return -ENOTCONN;
+        if (bus->state == BUS_RUNNING)
+                return 1;
+
+        for (;;) {
+                r = sd_bus_process(bus, NULL);
+                if (r < 0)
+                        return r;
+                if (bus->state == BUS_RUNNING)
+                        return 1;
+                if (r > 0)
+                        continue;
+
+                r = sd_bus_wait(bus, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
 int sd_bus_send_with_reply_and_block(
                 sd_bus *bus,
                 sd_bus_message *m,
@@ -1125,15 +1337,21 @@ int sd_bus_send_with_reply_and_block(
 
         if (!bus)
                 return -EINVAL;
-        if (!bus->fd < 0)
+        if (!BUS_IS_OPEN(bus->state))
                 return -ENOTCONN;
         if (!m)
                 return -EINVAL;
-        if (!m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+        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 (sd_bus_error_is_set(error))
+        if (bus_error_is_dirty(error))
                 return -EINVAL;
 
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
         r = sd_bus_send(bus, m, &serial);
         if (r < 0)
                 return r;
@@ -1142,11 +1360,14 @@ int sd_bus_send_with_reply_and_block(
 
         for (;;) {
                 usec_t left;
-                sd_bus_message *incoming;
+                sd_bus_message *incoming = NULL;
 
                 if (!room) {
                         sd_bus_message **q;
 
+                        if (bus->rqueue_size >= BUS_RQUEUE_MAX)
+                                return -ENOBUFS;
+
                         /* Make sure there's room for queuing this
                          * locally, before we read the message */
 
@@ -1158,15 +1379,24 @@ int sd_bus_send_with_reply_and_block(
                         room = true;
                 }
 
-                r = message_read(bus, &incoming);
+                if (bus->is_kernel)
+                        r = bus_kernel_read_message(bus, &incoming);
+                else
+                        r = bus_socket_read_message(bus, &incoming);
                 if (r < 0)
                         return r;
-                if (r > 0) {
+                if (incoming) {
+
                         if (incoming->reply_serial == serial) {
                                 /* Found a match! */
 
                                 if (incoming->header->type == SD_BUS_MESSAGE_TYPE_METHOD_RETURN) {
-                                        *reply = incoming;
+
+                                        if (reply)
+                                                *reply = incoming;
+                                        else
+                                                sd_bus_message_unref(incoming);
+
                                         return 0;
                                 }
 
@@ -1196,6 +1426,8 @@ int sd_bus_send_with_reply_and_block(
                         /* Try to read more, right-away */
                         continue;
                 }
+                if (r != 0)
+                        continue;
 
                 if (timeout > 0) {
                         usec_t n;
@@ -1208,7 +1440,7 @@ int sd_bus_send_with_reply_and_block(
                 } else
                         left = (uint64_t) -1;
 
-                r = sd_bus_wait(bus, left);
+                r = bus_poll(bus, true, left);
                 if (r < 0)
                         return r;
 
@@ -1221,11 +1453,12 @@ int sd_bus_send_with_reply_and_block(
 int sd_bus_get_fd(sd_bus *bus) {
         if (!bus)
                 return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+        if (bus->input_fd != bus->output_fd)
+                return -EPERM;
 
-        if (bus->fd < 0)
-                return -EINVAL;
-
-        return bus->fd;
+        return bus->input_fd;
 }
 
 int sd_bus_get_events(sd_bus *bus) {
@@ -1233,13 +1466,19 @@ int sd_bus_get_events(sd_bus *bus) {
 
         if (!bus)
                 return -EINVAL;
-
-        if (bus->fd < 0)
-                return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
 
         if (bus->state == BUS_OPENING)
                 flags |= POLLOUT;
-        else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
+        else if (bus->state == BUS_AUTHENTICATING) {
+
+                if (bus_socket_auth_needs_write(bus))
+                        flags |= POLLOUT;
+
+                flags |= POLLIN;
+
+        } else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
                 if (bus->rqueue_size <= 0)
                         flags |= POLLIN;
                 if (bus->wqueue_size > 0)
@@ -1249,156 +1488,643 @@ int sd_bus_get_events(sd_bus *bus) {
         return flags;
 }
 
-int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
-        sd_bus_message *m;
-        int r;
+int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
+        struct reply_callback *c;
 
         if (!bus)
                 return -EINVAL;
-        if (bus->fd < 0)
+        if (!timeout_usec)
+                return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
                 return -ENOTCONN;
 
-        if (bus->state == BUS_OPENING) {
-                struct pollfd p;
+        if (bus->state == BUS_AUTHENTICATING) {
+                *timeout_usec = bus->auth_timeout;
+                return 1;
+        }
 
-                zero(p);
-                p.fd = bus->fd;
-                p.events = POLLOUT;
+        if (bus->state != BUS_RUNNING && bus->state != BUS_HELLO) {
+                *timeout_usec = (uint64_t) -1;
+                return 0;
+        }
 
-                r = poll(&p, 1, 0);
-                if (r < 0)
-                        return -errno;
+        c = prioq_peek(bus->reply_callbacks_prioq);
+        if (!c) {
+                *timeout_usec = (uint64_t) -1;
+                return 0;
+        }
 
-                if (p.revents & (POLLOUT|POLLERR|POLLHUP)) {
-                        int error;
-                        socklen_t slen = sizeof(error);
+        *timeout_usec = c->timeout;
+        return 1;
+}
 
-                        r = getsockopt(bus->fd, SOL_SOCKET, SO_ERROR, &error, &slen);
-                        if (r < 0)
-                                return -errno;
+static int process_timeout(sd_bus *bus) {
+        _cleanup_bus_message_unref_ sd_bus_message* m = NULL;
+        struct reply_callback *c;
+        usec_t n;
+        int r;
 
-                        if (error != 0)
-                                bus->last_connect_error = -error;
-                        else if (p.revents & (POLLERR|POLLHUP))
-                                bus->last_connect_error = -ECONNREFUSED;
-                        else
-                                return bus_start_auth(bus);
+        assert(bus);
 
-                        /* Try next address */
-                        return bus_start_connect(bus);
-                }
+        c = prioq_peek(bus->reply_callbacks_prioq);
+        if (!c)
+                return 0;
 
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout > n)
                 return 0;
 
-        } else if (bus->state == BUS_AUTHENTICATING) {
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->serial,
+                        &SD_BUS_ERROR_MAKE("org.freedesktop.DBus.Error.Timeout", "Timed out"),
+                        &m);
+        if (r < 0)
+                return r;
 
-                r = bus_write_auth(bus);
-                if (r < 0)
-                        return r;
+        assert_se(prioq_pop(bus->reply_callbacks_prioq) == c);
+        hashmap_remove(bus->reply_callbacks, &c->serial);
 
-                r = bus_read_auth(bus);
-                if (r <= 0)
-                        return r;
+        r = c->callback(bus, m, c->userdata);
+        free(c);
 
-                return bus_start_running(bus);
+        return r < 0 ? r : 1;
+}
 
-        } else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
-                struct filter_callback *l;
+static int process_hello(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
 
-                r = dispatch_wqueue(bus);
-                if (r < 0)
-                        return r;
+        if (bus->state != BUS_HELLO)
+                return 0;
 
-                r = dispatch_rqueue(bus, &m);
-                if (r <= 0)
-                        return r;
+        /* 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_TYPE_METHOD_CALL || m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_RETURN) {
-                        struct reply_callback *c;
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_RETURN &&
+            m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_ERROR)
+                return -EIO;
 
-                        c = hashmap_remove(bus->reply_callbacks, &m->reply_serial);
-                        if (c) {
-                                r = c->callback(bus, m, c->userdata);
-                                free(c);
+        if (m->reply_serial != bus->hello_serial)
+                return -EIO;
 
-                                if (r != 0) {
-                                        sd_bus_message_unref(m);
-                                        return r < 0 ? r : 0;
-                                }
-                        }
-                }
+        return 0;
+}
 
-                LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
-                        r = l->callback(bus, m, l->userdata);
-                        if (r != 0) {
-                                sd_bus_message_unref(m);
-                                return r < 0 ? r : 0;
-                        }
-                }
+static int process_reply(sd_bus *bus, sd_bus_message *m) {
+        struct reply_callback *c;
+        int r;
 
-                if (ret) {
-                        *ret = m;
-                        return 1;
-                }
+        assert(bus);
+        assert(m);
 
-                sd_bus_message_unref(m);
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_RETURN &&
+            m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_ERROR)
                 return 0;
-        }
-
-        return -ENOTSUP;
-}
-
-int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
-        struct pollfd p;
-        int r, e;
-        struct timespec ts;
-
-        if (!bus)
-                return -EINVAL;
-        if (bus->fd < 0)
-                return -ECONNREFUSED;
 
-        e = sd_bus_get_events(bus);
-        if (e < 0)
-                return e;
+        c = hashmap_remove(bus->reply_callbacks, &m->reply_serial);
+        if (!c)
+                return 0;
 
-        zero(p);
-        p.fd = bus->fd;
-        p.events = e;
+        if (c->timeout != 0)
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
 
-        r = ppoll(&p, 1, timeout_usec == (uint64_t) -1 ? NULL : timespec_store(&ts, timeout_usec), NULL);
+        r = sd_bus_message_rewind(m, true);
         if (r < 0)
-                return -EINVAL;
+                return r;
+
+        r = c->callback(bus, m, c->userdata);
+        free(c);
 
         return r;
 }
 
-int sd_bus_flush(sd_bus *bus) {
+static int process_filter(sd_bus *bus, sd_bus_message *m) {
+        struct filter_callback *l;
         int r;
 
-        if (!bus)
-                return -EINVAL;
-        if (bus->fd < 0)
-                return -ENOTCONN;
+        assert(bus);
+        assert(m);
 
-        if (bus->state == BUS_RUNNING && bus->wqueue_size <= 0)
-                return 0;
+        do {
+                bus->filter_callbacks_modified = false;
 
-        for (;;) {
-                r = dispatch_wqueue(bus);
-                if (r < 0)
-                        return r;
+                LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
 
-                if (bus->state == BUS_RUNNING && bus->wqueue_size <= 0)
-                        return 0;
+                        if (bus->filter_callbacks_modified)
+                                break;
 
-                r = sd_bus_wait(bus, (uint64_t) -1);
+                        /* 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);
+                        if (r != 0)
+                                return r;
+
+                }
+
+        } while (bus->filter_callbacks_modified);
+
+        return 0;
+}
+
+static int process_match(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->match_callbacks_modified = false;
+
+                r = bus_match_run(bus, &bus->match_callbacks, m);
+                if (r != 0)
+                        return r;
+
+        } while (bus->match_callbacks_modified);
+
+        return 0;
+}
+
+static int process_builtin(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return 0;
+
+        if (!streq_ptr(m->interface, "org.freedesktop.DBus.Peer"))
+                return 0;
+
+        if (m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 1;
+
+        if (streq_ptr(m->member, "Ping"))
+                r = sd_bus_message_new_method_return(bus, m, &reply);
+        else if (streq_ptr(m->member, "GetMachineId")) {
+                sd_id128_t id;
+                char sid[33];
+
+                r = sd_id128_get_machine(&id);
                 if (r < 0)
                         return r;
+
+                r = sd_bus_message_new_method_return(bus, 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_NULL;
+
+                sd_bus_error_set(&error,
+                                 "org.freedesktop.DBus.Error.UnknownMethod",
+                                 "Unknown method '%s' on interface '%s'.", m->member, m->interface);
+
+                r = sd_bus_message_new_method_error(bus, m, &error, &reply);
         }
+
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int process_object(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        struct object_callback *c;
+        int r;
+        bool found = false;
+        size_t pl;
+
+        assert(bus);
+        assert(m);
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return 0;
+
+        if (hashmap_isempty(bus->object_callbacks))
+                return 0;
+
+        pl = strlen(m->path);
+
+        do {
+                char p[pl+1];
+
+                bus->object_callbacks_modified = false;
+
+                c = hashmap_get(bus->object_callbacks, m->path);
+                if (c && c->last_iteration != bus->iteration_counter) {
+
+                        c->last_iteration = bus->iteration_counter;
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        r = c->callback(bus, m, c->userdata);
+                        if (r != 0)
+                                return r;
+
+                        found = true;
+                }
+
+                /* Look for fallback prefixes */
+                strcpy(p, m->path);
+                for (;;) {
+                        char *e;
+
+                        if (bus->object_callbacks_modified)
+                                break;
+
+                        e = strrchr(p, '/');
+                        if (e == p || !e)
+                                break;
+
+                        *e = 0;
+
+                        c = hashmap_get(bus->object_callbacks, p);
+                        if (c && c->last_iteration != bus->iteration_counter && c->is_fallback) {
+
+                                c->last_iteration = bus->iteration_counter;
+
+                                r = sd_bus_message_rewind(m, true);
+                                if (r < 0)
+                                        return r;
+
+                                r = c->callback(bus, m, c->userdata);
+                                if (r != 0)
+                                        return r;
+
+                                found = true;
+                        }
+                }
+
+        } while (bus->object_callbacks_modified);
+
+        /* We found some handlers but none wanted to take this, then
+         * return this -- with one exception, we can handle
+         * introspection minimally ourselves */
+        if (!found || sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect"))
+                return 0;
+
+        sd_bus_error_set(&error,
+                         "org.freedesktop.DBus.Error.UnknownMethod",
+                         "Unknown method '%s' or interface '%s'.", m->member, m->interface);
+
+        r = sd_bus_message_new_method_error(bus, m, &error, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
 }
 
-int sd_bus_add_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata) {
+static int process_introspect(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_free_ char *introspection = NULL;
+        _cleanup_set_free_free_ Set *s = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        struct object_callback *c;
+        Iterator i;
+        size_t size = 0;
+        char *node;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (!sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect"))
+                return 0;
+
+        if (!m->path)
+                return 0;
+
+        s = set_new(string_hash_func, string_compare_func);
+        if (!s)
+                return -ENOMEM;
+
+        HASHMAP_FOREACH(c, bus->object_callbacks, i) {
+                const char *e;
+                char *a, *p;
+
+                if (streq(c->path, "/"))
+                        continue;
+
+                if (streq(m->path, "/"))
+                        e = c->path;
+                else {
+                        e = startswith(c->path, m->path);
+                        if (!e || *e != '/')
+                                continue;
+                }
+
+                a = strdup(e+1);
+                if (!a)
+                        return -ENOMEM;
+
+                p = strchr(a, '/');
+                if (p)
+                        *p = 0;
+
+                r = set_consume(s, a);
+                if (r < 0 && r != -EEXIST)
+                        return r;
+        }
+
+        f = open_memstream(&introspection, &size);
+        if (!f)
+                return -ENOMEM;
+
+        fputs(SD_BUS_INTROSPECT_DOCTYPE, f);
+        fputs("<node>\n", f);
+        fputs(SD_BUS_INTROSPECT_INTERFACE_PEER, f);
+        fputs(SD_BUS_INTROSPECT_INTERFACE_INTROSPECTABLE, f);
+
+        while ((node = set_steal_first(s))) {
+                fprintf(f, " <node name=\"%s\"/>\n", node);
+                free(node);
+        }
+
+        fputs("</node>\n", f);
+
+        fflush(f);
+
+        if (ferror(f))
+                return -ENOMEM;
+
+        r = sd_bus_message_new_method_return(bus, m, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "s", introspection);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int process_message(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        bus->iteration_counter++;
+
+        r = process_hello(bus, m);
+        if (r != 0)
+                return r;
+
+        r = process_reply(bus, m);
+        if (r != 0)
+                return r;
+
+        r = process_filter(bus, m);
+        if (r != 0)
+                return r;
+
+        r = process_match(bus, m);
+        if (r != 0)
+                return r;
+
+        r = process_builtin(bus, m);
+        if (r != 0)
+                return r;
+
+        r = process_object(bus, m);
+        if (r != 0)
+                return r;
+
+        return process_introspect(bus, m);
+}
+
+static int process_running(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        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 = dispatch_rqueue(bus, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        r = process_message(bus, m);
+        if (r != 0)
+                goto null_message;
+
+        if (ret) {
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                *ret = m;
+                m = NULL;
+                return 1;
+        }
+
+        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_NULL;
+
+                sd_bus_error_set(&error, "org.freedesktop.DBus.Error.UnknownObject", "Unknown object '%s'.", m->path);
+
+                r = sd_bus_message_new_method_error(bus, m, &error, &reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_send(bus, reply, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
+        int r;
+
+        /* Returns 0 when we didn't do anything. This should cause the
+         * caller to invoke sd_bus_wait() before returning the next
+         * time. Returns > 0 when we did something, which possibly
+         * means *ret is filled in with an unprocessed message. */
+
+        if (!bus)
+                return -EINVAL;
+
+        /* We don't allow recursively invoking sd_bus_process(). */
+        if (bus->processing)
+                return -EBUSY;
+
+        switch (bus->state) {
+
+        case BUS_UNSET:
+        case BUS_CLOSED:
+                return -ENOTCONN;
+
+        case BUS_OPENING:
+                r = bus_socket_process_opening(bus);
+                if (r < 0)
+                        return r;
+                if (ret)
+                        *ret = NULL;
+                return r;
+
+        case BUS_AUTHENTICATING:
+
+                r = bus_socket_process_authenticating(bus);
+                if (r < 0)
+                        return r;
+                if (ret)
+                        *ret = NULL;
+                return r;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+
+                bus->processing = true;
+                r = process_running(bus, ret);
+                bus->processing = false;
+
+                return r;
+        }
+
+        assert_not_reached("Unknown state");
+}
+
+static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
+        struct pollfd p[2] = {};
+        int r, e, n;
+        struct timespec ts;
+        usec_t until, m;
+
+        assert(bus);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        e = sd_bus_get_events(bus);
+        if (e < 0)
+                return e;
+
+        if (need_more)
+                e |= POLLIN;
+
+        r = sd_bus_get_timeout(bus, &until);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                m = (uint64_t) -1;
+        else {
+                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;
+
+        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, 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) {
+
+        if (!bus)
+                return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+        if (bus->rqueue_size > 0)
+                return 0;
+
+        return bus_poll(bus, false, timeout_usec);
+}
+
+int sd_bus_flush(sd_bus *bus) {
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        if (bus->wqueue_size <= 0)
+                return 0;
+
+        for (;;) {
+                r = dispatch_wqueue(bus);
+                if (r < 0)
+                        return r;
+
+                if (bus->wqueue_size <= 0)
+                        return 0;
+
+                r = bus_poll(bus, false, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
+int sd_bus_add_filter(sd_bus *bus, sd_bus_message_handler_t callback, void *userdata) {
         struct filter_callback *f;
 
         if (!bus)
@@ -1406,17 +2132,18 @@ int sd_bus_add_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata
         if (!callback)
                 return -EINVAL;
 
-        f = new(struct filter_callback, 1);
+        f = new0(struct filter_callback, 1);
         if (!f)
                 return -ENOMEM;
         f->callback = callback;
         f->userdata = userdata;
 
+        bus->filter_callbacks_modified = true;
         LIST_PREPEND(struct filter_callback, callbacks, bus->filter_callbacks, f);
         return 0;
 }
 
-int sd_bus_remove_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata) {
+int sd_bus_remove_filter(sd_bus *bus, sd_bus_message_handler_t callback, void *userdata) {
         struct filter_callback *f;
 
         if (!bus)
@@ -1426,6 +2153,7 @@ int sd_bus_remove_filter(sd_bus *bus, sd_message_handler_t callback, void *userd
 
         LIST_FOREACH(callbacks, f, bus->filter_callbacks) {
                 if (f->callback == callback && f->userdata == userdata) {
+                        bus->filter_callbacks_modified = true;
                         LIST_REMOVE(struct filter_callback, callbacks, bus->filter_callbacks, f);
                         free(f);
                         return 1;
@@ -1434,3 +2162,265 @@ 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_bus_message_handler_t callback,
+                void *userdata) {
+
+        struct object_callback *c;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!path)
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+
+        r = hashmap_ensure_allocated(&bus->object_callbacks, string_hash_func, string_compare_func);
+        if (r < 0)
+                return r;
+
+        c = new0(struct object_callback, 1);
+        if (!c)
+                return -ENOMEM;
+
+        c->path = strdup(path);
+        if (!c->path) {
+                free(c);
+                return -ENOMEM;
+        }
+
+        c->callback = callback;
+        c->userdata = userdata;
+        c->is_fallback = fallback;
+
+        bus->object_callbacks_modified = true;
+        r = hashmap_put(bus->object_callbacks, c->path, c);
+        if (r < 0) {
+                free(c->path);
+                free(c);
+                return r;
+        }
+
+        return 0;
+}
+
+static int bus_remove_object(
+                sd_bus *bus,
+                bool fallback,
+                const char *path,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        struct object_callback *c;
+
+        if (!bus)
+                return -EINVAL;
+        if (!path)
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+
+        c = hashmap_get(bus->object_callbacks, path);
+        if (!c)
+                return 0;
+
+        if (c->callback != callback || c->userdata != userdata || c->is_fallback != fallback)
+                return 0;
+
+        bus->object_callbacks_modified = true;
+        assert_se(c == hashmap_remove(bus->object_callbacks, c->path));
+
+        free(c->path);
+        free(c);
+
+        return 1;
+}
+
+int sd_bus_add_object(sd_bus *bus, const char *path, sd_bus_message_handler_t callback, void *userdata) {
+        return bus_add_object(bus, false, path, callback, userdata);
+}
+
+int sd_bus_remove_object(sd_bus *bus, const char *path, sd_bus_message_handler_t callback, void *userdata) {
+        return bus_remove_object(bus, false, path, callback, userdata);
+}
+
+int sd_bus_add_fallback(sd_bus *bus, const char *prefix, sd_bus_message_handler_t callback, void *userdata) {
+        return bus_add_object(bus, true, prefix, callback, userdata);
+}
+
+int sd_bus_remove_fallback(sd_bus *bus, const char *prefix, sd_bus_message_handler_t callback, void *userdata) {
+        return bus_remove_object(bus, true, prefix, callback, userdata);
+}
+
+int sd_bus_add_match(sd_bus *bus, const char *match, sd_bus_message_handler_t callback, void *userdata) {
+        int r = 0;
+
+        if (!bus)
+                return -EINVAL;
+        if (!match)
+                return -EINVAL;
+
+        if (bus->bus_client) {
+                r = bus_add_match_internal(bus, match);
+                if (r < 0)
+                        return r;
+        }
+
+        if (callback) {
+                bus->match_callbacks_modified = true;
+                r = bus_match_add(&bus->match_callbacks, match, callback, userdata, NULL);
+                if (r < 0) {
+
+                        if (bus->bus_client)
+                                bus_remove_match_internal(bus, match);
+                }
+        }
+
+        return r;
+}
+
+int sd_bus_remove_match(sd_bus *bus, const char *match, sd_bus_message_handler_t callback, void *userdata) {
+        int r = 0, q = 0;
+
+        if (!bus)
+                return -EINVAL;
+        if (!match)
+                return -EINVAL;
+
+        if (bus->bus_client)
+                r = bus_remove_match_internal(bus, match);
+
+        if (callback) {
+                bus->match_callbacks_modified = true;
+                q = bus_match_remove(&bus->match_callbacks, match, callback, userdata);
+        }
+
+        if (r < 0)
+                return r;
+        return q;
+}
+
+int sd_bus_emit_signal(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *member,
+                const char *types, ...) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        va_list ap;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+
+        r = sd_bus_message_new_signal(bus, path, interface, member, &m);
+        if (r < 0)
+                return r;
+
+        va_start(ap, types);
+        r = bus_message_append_ap(m, types, ap);
+        va_end(ap);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+int sd_bus_call_method(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                sd_bus_message **reply,
+                const char *types, ...) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        va_list ap;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(bus, destination, path, interface, member, &m);
+        if (r < 0)
+                return r;
+
+        va_start(ap, types);
+        r = bus_message_append_ap(m, types, ap);
+        va_end(ap);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send_with_reply_and_block(bus, m, 0, error, reply);
+}
+
+int sd_bus_reply_method_return(
+                sd_bus *bus,
+                sd_bus_message *call,
+                const char *types, ...) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        va_list ap;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!call)
+                return -EINVAL;
+        if (!call->sealed)
+                return -EPERM;
+        if (call->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EINVAL;
+
+        if (call->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        r = sd_bus_message_new_method_return(bus, call, &m);
+        if (r < 0)
+                return r;
+
+        va_start(ap, types);
+        r = bus_message_append_ap(m, types, ap);
+        va_end(ap);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+int sd_bus_reply_method_error(
+                sd_bus *bus,
+                sd_bus_message *call,
+                const sd_bus_error *e) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!call)
+                return -EINVAL;
+        if (!call->sealed)
+                return -EPERM;
+        if (call->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EINVAL;
+        if (!sd_bus_error_is_set(e))
+                return -EINVAL;
+
+        if (call->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        r = sd_bus_message_new_method_error(bus, call, e, &m);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send(bus, m, NULL);
+}