bus: add basic implementation of a native bus client library

18 files changed, 4480 insertions, 0 deletions

diff --git a/src/libsystemd-bus/Makefile b/src/libsystemd-bus/Makefile
new file mode 120000
index 0000000000..d0b0e8e008
--- /dev/null
+++ b/src/libsystemd-bus/Makefile
@@ -0,0 +1 @@
+../Makefile
\ No newline at end of file
diff --git a/src/libsystemd-bus/bus-control.c b/src/libsystemd-bus/bus-control.c
new file mode 100644
index 0000000000..e4cc251a4b
--- /dev/null
+++ b/src/libsystemd-bus/bus-control.c
@@ -0,0 +1,322 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stddef.h>
+#include <errno.h>
+
+#include "strv.h"
+
+#include "sd-bus.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+
+const char *sd_bus_get_unique_name(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        return bus->unique_name;
+}
+
+int sd_bus_request_name(sd_bus *bus, const char *name, int flags) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        uint32_t ret;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "RequestName",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "su", name, flags);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &ret);
+        if (r < 0)
+                return r;
+
+        return ret;
+}
+
+int sd_bus_release_name(sd_bus *bus, const char *name) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        uint32_t ret;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "ReleaseName",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &ret);
+        if (r < 0)
+                return r;
+
+        return ret;
+}
+
+int sd_bus_list_names(sd_bus *bus, char ***l) {
+        _cleanup_bus_message_unref_ sd_bus_message *m1 = NULL, *reply1 = NULL, *m2 = NULL, *reply2 = NULL;
+        _cleanup_strv_free_ char **a = NULL, **b = NULL;
+        char **x = NULL;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!l)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "ListNames",
+                        &m1);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "ListActivatableNames",
+                        &m2);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m1, (uint64_t) -1, NULL, &reply1);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m2, (uint64_t) -1, NULL, &reply2);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply1, "as", &a);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply2, "as", &b);
+        if (r < 0)
+                return r;
+
+        x = strv_merge(a, b);
+        if (!x)
+                return -ENOMEM;
+
+        *l = strv_uniq(x);
+        return 0;
+}
+
+int sd_bus_get_owner(sd_bus *bus, const char *name, char **owner) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "GetNameOwner",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        return sd_bus_message_read(reply, "s", owner);
+}
+
+int sd_bus_get_owner_uid(sd_bus *bus, const char *name, uid_t *uid) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        uint32_t u;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+        if (!uid)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "GetConnectionUnixUser",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &u);
+        if (r < 0)
+                return r;
+
+        *uid = (uid_t) u;
+        return 0;
+}
+
+int sd_bus_get_owner_pid(sd_bus *bus, const char *name, pid_t *pid) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        uint32_t u;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+        if (!pid)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "GetConnectionUnixUser",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &u);
+        if (r < 0)
+                return r;
+
+        if (u == 0)
+                return -EIO;
+
+        *pid = (uid_t) u;
+        return 0;
+}
+
+int sd_bus_add_match(sd_bus *bus, const char *match) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!match)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "AddMatch",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", match);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+}
+
+int sd_bus_remove_match(sd_bus *bus, const char *match) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!match)
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "RemoveMatch",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", match);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send_with_reply_and_block(bus, m, (uint64_t) -1, NULL, &reply);
+}
diff --git a/src/libsystemd-bus/bus-error.c b/src/libsystemd-bus/bus-error.c
new file mode 100644
index 0000000000..0832022ee9
--- /dev/null
+++ b/src/libsystemd-bus/bus-error.c
@@ -0,0 +1,166 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "util.h"
+
+#include "sd-bus.h"
+#include "bus-error.h"
+
+void sd_bus_error_free(sd_bus_error *e) {
+        if (!e)
+                return;
+
+        if (e->need_free) {
+                free((void*) e->name);
+                free((void*) e->message);
+        }
+
+        e->name = e->message = NULL;
+        e->need_free = false;
+}
+
+int sd_bus_error_set(sd_bus_error *e, const char *name, const char *format, ...) {
+        char *n, *m = NULL;
+        va_list ap;
+        int r;
+
+        if (!e)
+                return 0;
+        if (sd_bus_error_is_set(e))
+                return -EINVAL;
+        if (!name)
+                return -EINVAL;
+
+        n = strdup(name);
+        if (!n)
+                return -ENOMEM;
+
+        if (format) {
+                va_start(ap, format);
+                r = vasprintf(&m, format, ap);
+                va_end(ap);
+
+                if (r < 0) {
+                        free(n);
+                        return -ENOMEM;
+                }
+        }
+
+        e->name = n;
+        e->message = m;
+        e->need_free = true;
+
+        return 0;
+}
+
+int sd_bus_error_copy(sd_bus_error *dest, const sd_bus_error *e) {
+        if (!dest)
+                return 0;
+        if (sd_bus_error_is_set(dest))
+                return -EINVAL;
+        if (!sd_bus_error_is_set(e))
+                return 0;
+
+        if (e->need_free) {
+                char *x, *y = NULL;
+
+                x = strdup(e->name);
+                if (!x)
+                        return -ENOMEM;
+
+                if (e->message) {
+                        y = strdup(e->message);
+                        if (!y) {
+                                free(x);
+                                return -ENOMEM;
+                        }
+                }
+
+                dest->name = x;
+                dest->message = y;
+                dest->need_free = true;
+        } else
+                *dest = *e;
+
+        return 0;
+}
+
+void sd_bus_error_set_const(sd_bus_error *e, const char *name, const char *message) {
+        if (!e)
+                return;
+        if (sd_bus_error_is_set(e))
+                return;
+
+        e->name = name;
+        e->message = message;
+}
+
+int sd_bus_error_is_set(const sd_bus_error *e) {
+        if (!e)
+                return 0;
+
+        return e->name || e->message || e->need_free;
+}
+
+int sd_bus_error_has_name(const sd_bus_error *e, const char *name) {
+        if (!e)
+                return 0;
+
+        return streq_ptr(e->name, name);
+}
+
+int bus_error_to_errno(const sd_bus_error* e) {
+
+        /* Better replce this with a gperf table */
+
+        if (!e->name)
+                return -EIO;
+
+        if (streq(e->name, "org.freedesktop.DBus.Error.NoMemory"))
+                return -ENOMEM;
+
+        if (streq(e->name, "org.freedesktop.DBus.Error.AuthFailed") ||
+            streq(e->name, "org.freedesktop.DBus.Error.AccessDenied"))
+                return -EPERM;
+
+        return -EIO;
+}
+
+int bus_error_from_errno(sd_bus_error *e, int error) {
+        if (!e)
+                return error;
+
+        if (error == -ENOMEM)
+                sd_bus_error_set_const(e, "org.freedesktop.DBus.Error.NoMemory", strerror(-error));
+        else if (error == -EPERM || error == EACCES)
+                sd_bus_error_set_const(e, "org.freedesktop.DBus.Error.AccessDenied", strerror(-error));
+        else
+                sd_bus_error_set_const(e, "org.freedesktop.DBus.Error.Failed", "Operation failed");
+
+        return error;
+}
diff --git a/src/libsystemd-bus/bus-error.h b/src/libsystemd-bus/bus-error.h
new file mode 100644
index 0000000000..f49e6c7398
--- /dev/null
+++ b/src/libsystemd-bus/bus-error.h
@@ -0,0 +1,27 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "sd-bus.h"
+
+int bus_error_to_errno(const sd_bus_error *e);
+int bus_error_from_errno(sd_bus_error *e, int error);
diff --git a/src/libsystemd-bus/bus-internal.c b/src/libsystemd-bus/bus-internal.c
new file mode 100644
index 0000000000..19398af6cb
--- /dev/null
+++ b/src/libsystemd-bus/bus-internal.c
@@ -0,0 +1,22 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "bus-internal.h"
diff --git a/src/libsystemd-bus/bus-internal.h b/src/libsystemd-bus/bus-internal.h
new file mode 100644
index 0000000000..d8cdc48ce0
--- /dev/null
+++ b/src/libsystemd-bus/bus-internal.h
@@ -0,0 +1,101 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+
+#include "hashmap.h"
+#include "list.h"
+#include "util.h"
+
+#include "sd-bus.h"
+#include "bus-error.h"
+
+struct reply_callback {
+        sd_message_handler_t callback;
+        void *userdata;
+        usec_t timeout;
+        uint64_t serial;
+};
+
+struct filter_callback {
+        sd_message_handler_t callback;
+        void *userdata;
+
+        LIST_FIELDS(struct filter_callback, callbacks);
+};
+
+enum bus_state {
+        BUS_OPENING,
+        BUS_AUTHENTICATING,
+        BUS_HELLO,
+        BUS_RUNNING,
+        BUS_CLOSED
+};
+
+struct sd_bus {
+        unsigned n_ref;
+        enum bus_state state;
+        int fd;
+        int message_version;
+        bool can_fds:1;
+        bool send_hello:1;
+
+        void *rbuffer;
+        size_t rbuffer_size;
+
+        sd_bus_message **rqueue;
+        unsigned rqueue_size;
+
+        sd_bus_message **wqueue;
+        unsigned wqueue_size;
+        size_t windex;
+
+        uint64_t serial;
+
+        char *unique_name;
+
+        Hashmap *reply_callbacks;
+        LIST_HEAD(struct filter_callback, filter_callbacks);
+
+        union {
+                struct sockaddr sa;
+                struct sockaddr_un un;
+                struct sockaddr_in in;
+                struct sockaddr_in6 in6;
+        } sockaddr;
+        socklen_t sockaddr_size;
+
+        sd_id128_t peer;
+
+        char *address;
+        unsigned address_index;
+
+        int last_connect_error;
+
+        struct iovec auth_iovec[3];
+        unsigned auth_index;
+        size_t auth_size;
+        char *auth_uid;
+};
diff --git a/src/libsystemd-bus/bus-message.c b/src/libsystemd-bus/bus-message.c
new file mode 100644
index 0000000000..4c5588cf8a
--- /dev/null
+++ b/src/libsystemd-bus/bus-message.c
@@ -0,0 +1,1413 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+
+#include "util.h"
+
+#include "bus-message.h"
+#include "sd-bus.h"
+#include "bus-internal.h"
+#include "bus-type.h"
+#include "bus-signature.h"
+
+int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored);
+
+static void message_free(sd_bus_message *m) {
+        unsigned i;
+
+        assert(m);
+
+        if (m->free_header)
+                free(m->header);
+
+        if (m->free_fields)
+                free(m->fields);
+
+        if (m->free_body)
+                free(m->body);
+
+        for (i = 0; i < m->n_fds; i++)
+                close_nointr_nofail(m->fds[i]);
+
+        for (i = 0; i < m->n_containers; i++)
+                free(m->sub_containers[i].signature);
+
+        free(m->sub_containers);
+        free(m);
+}
+
+static void* buffer_extend(void **p, uint32_t *sz, size_t align, size_t extend) {
+        size_t start, n;
+        void *k;
+
+        assert(p);
+        assert(sz);
+        assert(align > 0);
+
+        start = ALIGN_TO((size_t) *sz, align);
+        n = start + extend;
+
+        if (n == *sz)
+                return (uint8_t*) *p + start;
+
+        if (n > (size_t) ((uint32_t) -1))
+                return NULL;
+
+        k = realloc(*p, n);
+        if (!k)
+                return NULL;
+
+        /* Zero out padding */
+        if (start > *sz)
+                memset((uint8_t*) k + *sz, 0, start - *sz);
+
+        *p = k;
+        *sz = n;
+
+        return (uint8_t*) k + start;
+}
+
+static void *message_extend_fields(sd_bus_message *m, size_t align, size_t sz) {
+        void *p, *o;
+
+        assert(m);
+
+        o = m->fields;
+        p = buffer_extend(&m->fields, &m->header->fields_size, align, sz);
+        if (!p)
+                return NULL;
+
+        if (o != m->fields) {
+                /* Adjust quick access pointers */
+
+                if (m->path)
+                        m->path = (const char*) m->fields + (m->path - (const char*) o);
+                if (m->interface)
+                        m->interface = (const char*) m->fields + (m->interface - (const char*) o);
+                if (m->member)
+                        m->member = (const char*) m->fields + (m->member - (const char*) o);
+                if (m->destination)
+                        m->destination = (const char*) m->fields + (m->destination - (const char*) o);
+                if (m->sender)
+                        m->sender = (const char*) m->fields + (m->sender - (const char*) o);
+                if (m->signature)
+                        m->signature = (const char*) m->fields + (m->signature - (const char*) o);
+                if (m->error.name)
+                        m->error.name = (const char*) m->fields + (m->error.name - (const char*) o);
+        }
+
+        m->free_fields = true;
+
+        return p;
+}
+
+static int message_append_field_string(
+                sd_bus_message *m,
+                uint8_t h,
+                char type,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        l = strlen(s);
+        if (l > (size_t) (uint32_t) -1)
+                return -EINVAL;
+
+        /* field id byte + signature length + signature 's' + NUL + string length + string + NUL */
+        p = message_extend_fields(m, 8, 4 + 4 + l + 1);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = h;
+        p[1] = 1;
+        p[2] = type;
+        p[3] = 0;
+
+        ((uint32_t*) p)[1] = l;
+        memcpy(p + 8, s, l + 1);
+
+        if (ret)
+                *ret = (const char*) p + 8;
+
+        return 0;
+}
+
+static int message_append_field_signature(
+                sd_bus_message *m,
+                uint8_t h,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        l = strlen(s);
+        if (l > 255)
+                return -EINVAL;
+
+        /* field id byte + signature length + signature 'g' + NUL + string length + string + NUL */
+        p = message_extend_fields(m, 8, 4 + 1 + l + 1);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = h;
+        p[1] = 1;
+        p[2] = SD_BUS_TYPE_SIGNATURE;
+        p[3] = 0;
+        p[4] = l;
+        memcpy(p + 5, s, l + 1);
+
+        if (ret)
+                *ret = (const char*) p + 5;
+
+        return 0;
+}
+
+static int message_append_field_uint32(sd_bus_message *m, uint8_t h, uint32_t x) {
+        uint8_t *p;
+
+        assert(m);
+
+        /* field id byte + signature length + signature 'u' + NUL + value */
+        p = message_extend_fields(m, 8, 4 + 4);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = h;
+        p[1] = 1;
+        p[2] = SD_BUS_TYPE_UINT32;
+        p[3] = 0;
+
+        ((uint32_t*) p)[1] = x;
+
+        return 0;
+}
+
+static sd_bus_message *message_new(sd_bus *bus, uint8_t type) {
+        sd_bus_message *m;
+
+        m = malloc0(ALIGN(sizeof(struct sd_bus_message)) + sizeof(struct bus_header));
+        if (!m)
+                return NULL;
+
+        m->n_ref = 1;
+        m->header = (struct bus_header*) ((uint8_t*) m + ALIGN(sizeof(struct sd_bus_message)));
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+        m->header->endian = SD_BUS_BIG_ENDIAN;
+#else
+        m->header->endian = SD_BUS_LITTLE_ENDIAN;
+#endif
+        m->header->type = type;
+        m->header->version = bus ? bus->message_version : 1;
+
+        return m;
+}
+
+int sd_bus_message_new_signal(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message **m) {
+
+        sd_bus_message *t;
+        int r;
+
+        if (!path)
+                return -EINVAL;
+        if (!interface)
+                return -EINVAL;
+        if (!member)
+                return -EINVAL;
+
+        t = message_new(bus, SD_BUS_MESSAGE_TYPE_SIGNAL);
+        if (!t)
+                return -ENOMEM;
+
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                goto fail;
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+        if (r < 0)
+                goto fail;
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                goto fail;
+
+        *m = t;
+        return 0;
+
+fail:
+        sd_bus_message_unref(t);
+        return r;
+}
+
+int sd_bus_message_new_method_call(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message **m) {
+
+        sd_bus_message *t;
+        int r;
+
+        if (!path)
+                return -EINVAL;
+        if (!member)
+                return -EINVAL;
+
+        t = message_new(bus, SD_BUS_MESSAGE_TYPE_METHOD_CALL);
+        if (!t)
+                return -ENOMEM;
+
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                goto fail;
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                goto fail;
+
+        if (interface) {
+                r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+                if (r < 0)
+                        goto fail;
+        }
+
+        if (destination) {
+                r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &t->destination);
+                if (r < 0)
+                        goto fail;
+        }
+
+        *m = t;
+        return 0;
+
+fail:
+        message_free(t);
+        return r;
+}
+
+int sd_bus_message_new_method_return(
+                sd_bus *bus,
+                sd_bus_message *call,
+                sd_bus_message **m) {
+
+        sd_bus_message *t;
+        int r;
+
+        if (!call)
+                return -EINVAL;
+        if (call->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EINVAL;
+
+        t = message_new(bus, SD_BUS_MESSAGE_TYPE_METHOD_RETURN);
+        if (!t)
+                return -ENOMEM;
+
+        t->reply_serial = BUS_MESSAGE_SERIAL(call);
+        r = message_append_field_uint32(t, SD_BUS_MESSAGE_HEADER_REPLY_SERIAL, t->reply_serial);
+        if (r < 0)
+                goto fail;
+
+        if (call->sender) {
+                r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, call->sender, &t->sender);
+                if (r < 0)
+                        goto fail;
+        }
+
+        *m = t;
+        return 0;
+
+fail:
+        message_free(t);
+        return r;
+}
+
+int sd_bus_message_new_method_error(
+                sd_bus *bus,
+                sd_bus_message *call,
+                const sd_bus_error *e,
+                sd_bus_message **m) {
+
+        sd_bus_message *t;
+        int r;
+
+        if (!call)
+                return -EINVAL;
+        if (call->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EINVAL;
+        if (!e)
+                return -EINVAL;
+        if (!e->name)
+                return -EINVAL;
+
+        t = message_new(bus, SD_BUS_MESSAGE_TYPE_METHOD_ERROR);
+        if (!t)
+                return -ENOMEM;
+
+        t->reply_serial = BUS_MESSAGE_SERIAL(call);
+        r = message_append_field_uint32(t, SD_BUS_MESSAGE_HEADER_REPLY_SERIAL, t->reply_serial);
+        if (r < 0)
+                goto fail;
+
+        if (call->sender) {
+                r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, call->sender, &t->sender);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = message_append_field_string(t, SD_BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, e->name, &t->error.name);
+        if (r < 0)
+                goto fail;
+
+        if (e->message) {
+                r = message_append_basic(t, SD_BUS_TYPE_STRING, e->message, (const void**) &t->error.message);
+                if (r < 0)
+                        goto fail;
+        }
+
+        *m = t;
+        return 0;
+
+fail:
+        message_free(t);
+        return r;
+}
+
+sd_bus_message* sd_bus_message_ref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        assert(m->n_ref > 0);
+        m->n_ref++;
+
+        return m;
+}
+
+sd_bus_message* sd_bus_message_unref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        assert(m->n_ref > 0);
+        m->n_ref--;
+
+        if (m->n_ref <= 0)
+                message_free(m);
+
+        return NULL;
+}
+
+int sd_bus_message_get_type(sd_bus_message *m, uint8_t *type) {
+        if (!m)
+                return -EINVAL;
+        if (!type)
+                return -EINVAL;
+
+        *type = m->header->type;
+        return 0;
+}
+
+int sd_bus_message_get_serial(sd_bus_message *m, uint64_t *serial) {
+        if (!m)
+                return -EINVAL;
+        if (!serial)
+                return -EINVAL;
+        if (m->header->serial == 0)
+                return -ENOENT;
+
+        *serial = BUS_MESSAGE_SERIAL(m);
+        return 0;
+}
+
+int sd_bus_message_get_reply_serial(sd_bus_message *m, uint64_t *serial) {
+        if (!m)
+                return -EINVAL;
+        if (!serial)
+                return -EINVAL;
+        if (m->reply_serial == 0)
+                return -ENOENT;
+
+        *serial = m->reply_serial;
+        return 0;
+}
+
+int sd_bus_message_get_no_reply(sd_bus_message *m) {
+        if (!m)
+                return -EINVAL;
+
+        return m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_CALL ? !!(m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED) : 0;
+}
+
+const char *sd_bus_message_get_path(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        return m->path;
+}
+
+const char *sd_bus_message_get_interface(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        return m->interface;
+}
+
+const char *sd_bus_message_get_member(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        return m->member;
+}
+const char *sd_bus_message_get_destination(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        return m->destination;
+}
+
+const char *sd_bus_message_get_sender(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        return m->sender;
+}
+
+const sd_bus_error *sd_bus_message_get_error(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        if (!sd_bus_error_is_set(&m->error))
+                return NULL;
+
+        return &m->error;
+}
+
+int sd_bus_message_get_uid(sd_bus_message *m, uid_t *uid) {
+        if (!m)
+                return -EINVAL;
+        if (!m->uid_valid)
+                return -ENOENT;
+
+        *uid = m->uid;
+        return 0;
+}
+
+int sd_bus_message_get_gid(sd_bus_message *m, gid_t *gid) {
+        if (!m)
+                return -EINVAL;
+        if (!m->gid_valid)
+                return -ENOENT;
+
+        *gid = m->gid;
+        return 0;
+}
+
+int sd_bus_message_get_pid(sd_bus_message *m, pid_t *pid) {
+        if (!m)
+                return -EINVAL;
+        if (m->pid <= 0)
+                return -ENOENT;
+
+        *pid = m->pid;
+        return 0;
+}
+
+int sd_bus_message_get_tid(sd_bus_message *m, pid_t *tid) {
+        if (!m)
+                return -EINVAL;
+        if (m->tid <= 0)
+                return -ENOENT;
+
+        *tid = m->tid;
+        return 0;
+}
+
+int sd_bus_message_is_signal(sd_bus_message *m, const char *interface, const char *member) {
+        if (!m)
+                return -EINVAL;
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_SIGNAL)
+                return 0;
+
+        if (interface && (!m->interface || !streq(m->interface, interface)))
+                return 0;
+
+        if (member &&  (!m->member || !streq(m->member, member)))
+                return 0;
+
+        return 1;
+}
+
+int sd_bus_message_is_method_call(sd_bus_message *m, const char *interface, const char *member) {
+        if (!m)
+                return -EINVAL;
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return 0;
+
+        if (interface && (!m->interface || !streq(m->interface, interface)))
+                return 0;
+
+        if (member &&  (!m->member || !streq(m->member, member)))
+                return 0;
+
+        return 1;
+}
+
+int sd_bus_message_is_method_error(sd_bus_message *m, const char *name) {
+        if (!m)
+                return -EINVAL;
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_ERROR)
+                return 0;
+
+        if (name && (!m->error.name || !streq(m->error.name, name)))
+                return 0;
+
+        return 1;
+}
+
+int sd_bus_message_set_no_reply(sd_bus_message *m, int b) {
+        if (!m)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EPERM;
+
+        if (b)
+                m->header->flags |= SD_BUS_MESSAGE_NO_REPLY_EXPECTED;
+        else
+                m->header->flags &= ~SD_BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        return 0;
+}
+
+static struct bus_container *message_get_container(sd_bus_message *m) {
+        assert(m);
+
+        if (m->n_containers == 0)
+                return &m->root_container;
+
+        assert(m->sub_containers);
+        return m->sub_containers + m->n_containers - 1;
+}
+
+static void *message_extend_body(sd_bus_message *m, size_t align, size_t sz) {
+        void *p, *o;
+        size_t added;
+        struct bus_container *c;
+
+        assert(m);
+
+        o = m->body;
+        added = m->header->body_size;
+
+        p = buffer_extend(&m->body, &m->header->body_size, align, sz);
+        if (!p)
+                return NULL;
+
+        added = m->header->body_size - added;
+
+        for (c = m->sub_containers; c < m->sub_containers + m->n_containers; c++)
+                if (c->array_size) {
+                        c->array_size = (uint32_t*) ((uint8_t*) m->body + ((uint8_t*) c->array_size - (uint8_t*) o));
+                        *c->array_size += added;
+                }
+
+        if (o != m->body) {
+                if (m->error.message)
+                        m->error.message = (const char*) m->body + (m->error.message - (const char*) o);
+        }
+
+        m->free_body = true;
+
+        return p;
+}
+
+int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored) {
+        struct bus_container *c;
+        size_t sz, align, nindex;
+        uint32_t k;
+        void *a;
+        char *e = NULL;
+
+        if (!m)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (!bus_type_is_basic(type))
+                return -EINVAL;
+
+        c = message_get_container(m);
+
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != type)
+                        return -EINVAL;
+        } else {
+                /* Maybe we can append to the signature? But only if this is the top-level container*/
+                if (c->enclosing != 0)
+                        return -EINVAL;
+
+                e = strextend(&c->signature, CHAR_TO_STR(type), NULL);
+                if (!e)
+                        return -ENOMEM;
+        }
+
+        nindex = c->index + 1;
+
+        switch (type) {
+
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+                align = 4;
+                sz = 4 + strlen(p) + 1;
+                break;
+
+        case SD_BUS_TYPE_SIGNATURE:
+                align = 1;
+                sz = 1 + strlen(p) + 1;
+                break;
+
+        case SD_BUS_TYPE_BOOLEAN:
+                align = sz = 4;
+
+                assert_cc(sizeof(int) == sizeof(uint32_t));
+                memcpy(&k, p, 4);
+                k = !!k;
+                p = &k;
+                break;
+
+        default:
+                align = bus_type_get_alignment(type);
+                sz = bus_type_get_size(type);
+                break;
+        }
+
+        assert(align > 0);
+        assert(sz > 0);
+
+        a = message_extend_body(m, align, sz);
+        if (!a) {
+                /* Truncate extended signature again */
+                if (e)
+                        c->signature[c->index] = 0;
+
+                return -ENOMEM;
+        }
+
+        if (type == SD_BUS_TYPE_STRING || type == SD_BUS_TYPE_OBJECT_PATH) {
+                *(uint32_t*) a = sz - 5;
+                memcpy((uint8_t*) a + 4, p, sz - 4);
+
+                if (stored)
+                        *stored = (const uint8_t*) a + 4;
+
+        } else if (type == SD_BUS_TYPE_SIGNATURE) {
+                *(uint8_t*) a = sz - 1;
+                memcpy((uint8_t*) a + 1, p, sz - 1);
+
+                if (stored)
+                        *stored = (const uint8_t*) a + 1;
+
+        } else {
+                memcpy(a, p, sz);
+
+                if (stored)
+                        *stored = a;
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p) {
+        return message_append_basic(m, type, p, NULL);
+}
+
+static int bus_message_open_array(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                uint32_t **array_size) {
+
+        char *e = NULL;
+        size_t nindex;
+        void *a, *b;
+        int alignment;
+        size_t saved;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(array_size);
+
+        if (!signature_is_single(contents))
+                return -EINVAL;
+
+        alignment = bus_type_get_alignment(contents[0]);
+        if (alignment < 0)
+                return alignment;
+
+        if (c->signature && c->signature[c->index]) {
+
+                /* Verify the existing signature */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_ARRAY)
+                        return -EINVAL;
+
+                if (!startswith(c->signature + c->index + 1, contents))
+                        return -EINVAL;
+
+                nindex = c->index + 1 + strlen(contents);
+        } else {
+                if (c->enclosing != 0)
+                        return -EINVAL;
+
+                /* Extend the existing signature */
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_ARRAY), contents, NULL);
+                if (!e)
+                        return -ENOMEM;
+
+                nindex = e - c->signature;
+        }
+
+        saved = m->header->body_size;
+        a = message_extend_body(m, 4, 4);
+        if (!a) {
+                /* Truncate extended signature again */
+                if (e)
+                        c->signature[c->index] = 0;
+
+                return -ENOMEM;
+        }
+        b = m->body;
+
+        if (!message_extend_body(m, alignment, 0)) {
+                /* Add alignment between size and first element */
+                if (e)
+                        c->signature[c->index] = 0;
+
+                m->header->body_size = saved;
+                return -ENOMEM;
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        /* m->body might have changed so let's readjust a */
+        a = (uint8_t*) m->body + ((uint8_t*) a - (uint8_t*) b);
+        *(uint32_t*) a = 0;
+
+        *array_size = a;
+        return 0;
+}
+
+static int bus_message_open_variant(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        char *e = NULL;
+        size_t l, nindex;
+        void *a;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_single(contents))
+                return -EINVAL;
+
+        if (*contents == SD_BUS_TYPE_DICT_ENTRY_BEGIN)
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+
+                if (c->signature[c->index] != SD_BUS_TYPE_VARIANT)
+                        return -EINVAL;
+
+        } else {
+                if (c->enclosing != 0)
+                        return -EINVAL;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_VARIANT), NULL);
+                if (!e)
+                        return -ENOMEM;
+        }
+
+        nindex = c->index + 1;
+
+        l = strlen(contents);
+        a = message_extend_body(m, 1, 1 + l + 1);
+        if (!a) {
+                /* Truncate extended signature again */
+                if (e)
+                        c->signature[c->index] = 0;
+
+                return -ENOMEM;
+        }
+
+        *(uint8_t*) a = l;
+        memcpy((uint8_t*) a + 1, contents, l + 1);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+static int bus_message_open_struct(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t nindex;
+        char *e = NULL;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_valid(contents, false))
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+                size_t l;
+
+                l = strlen(contents);
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRUCT_BEGIN ||
+                    !startswith(c->signature + c->index + 1, contents) ||
+                    c->signature[c->index + 1 + l] != SD_BUS_TYPE_STRUCT_END)
+                        return -EINVAL;
+
+                nindex = c->index + 1 + l + 1;
+        } else {
+                if (c->enclosing != 0)
+                        return -EINVAL;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_BEGIN), contents, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_END), NULL);
+                if (!e)
+                        return -ENOMEM;
+
+                nindex = e - c->signature;
+        }
+
+        /* Align contents to 8 byte boundary */
+        if (!message_extend_body(m, 8, 0)) {
+                if (e)
+                        c->signature[c->index] = 0;
+
+                return -ENOMEM;
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+static int bus_message_open_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t nindex;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_pair(contents))
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+                size_t l;
+
+                l = strlen(contents);
+
+                if (c->signature[c->index] != SD_BUS_TYPE_DICT_ENTRY_BEGIN ||
+                    !startswith(c->signature + c->index + 1, contents) ||
+                    c->signature[c->index + 1 + l] != SD_BUS_TYPE_DICT_ENTRY_END)
+                        return -EINVAL;
+
+                nindex = c->index + 1 + l + 1;
+        } else
+                return -EINVAL;
+
+        /* Align contents to 8 byte boundary */
+        if (!message_extend_body(m, 8, 0))
+                return -ENOMEM;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+int sd_bus_message_open_container(
+                sd_bus_message *m,
+                char type,
+                const char *contents) {
+
+        struct bus_container *c, *sub;
+        char *signature;
+        uint32_t *array_size = NULL;
+        int r;
+
+        if (!m)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (!contents)
+                return -EINVAL;
+
+        /* Make sure we have space for one more container */
+        sub = realloc(m->sub_containers, sizeof(struct bus_container) * (m->n_containers + 1));
+        if (!sub)
+                return -ENOMEM;
+
+        m->sub_containers = sub;
+
+        c = message_get_container(m);
+
+        signature = strdup(contents);
+        if (!signature)
+                return -ENOMEM;
+
+        if (type == SD_BUS_TYPE_ARRAY)
+                r = bus_message_open_array(m, c, contents, &array_size);
+        else if (type == SD_BUS_TYPE_VARIANT)
+                r = bus_message_open_variant(m, c, contents);
+        else if (type == SD_BUS_TYPE_STRUCT)
+                r = bus_message_open_struct(m, c, contents);
+        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                r = bus_message_open_dict_entry(m, c, contents);
+        else
+                r = -EINVAL;
+
+        if (r < 0) {
+                free(signature);
+                return r;
+        }
+
+        /* OK, let's fill it in */
+        sub += m->n_containers++;
+
+        sub->enclosing = type;
+        sub->signature = signature;
+        sub->index = 0;
+        sub->array_size = array_size;
+
+        return 0;
+}
+
+int sd_bus_message_close_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        if (!m)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (m->n_containers <= 0)
+                return -EINVAL;
+
+        c = message_get_container(m);
+
+        if (!c->signature)
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                if (c->signature[c->index] != 0)
+                        return -EINVAL;
+
+        free(c->signature);
+        m->n_containers--;
+
+        return 0;
+}
+
+static int message_append_ap(
+                sd_bus_message *m,
+                const char *types,
+                va_list ap) {
+
+        const char *t;
+        int r;
+
+        assert(m);
+        assert(types);
+
+        for (t = types; *t; t++) {
+                switch (*t) {
+
+                case SD_BUS_TYPE_BYTE: {
+                        uint8_t x;
+
+                        x = (uint8_t) va_arg(ap, int);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32: {
+                        uint32_t x;
+
+                        x = va_arg(ap, uint32_t);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16: {
+                        uint16_t x;
+
+                        x = (uint16_t) va_arg(ap, int);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE: {
+                        uint64_t x;
+
+                        x = va_arg(ap, uint64_t);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE: {
+                        const char *x;
+
+                        x = va_arg(ap, const char*);
+                        r = sd_bus_message_append_basic(m, *t, x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_UNIX_FD: {
+                        int x;
+
+                        x = va_arg(ap, int);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_ARRAY: {
+                        unsigned i, n;
+                        size_t k;
+
+                        r = signature_element_length(t + 1, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k + 1];
+
+                                memcpy(s, t + 1, k);
+                                s[k] = 0;
+                                t += k;
+
+                                r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, s);
+                                if (r < 0)
+                                        return r;
+
+                                n = va_arg(ap, unsigned);
+
+                                for (i = 0; i < n; i++) {
+                                        r = message_append_ap(m, s, ap);
+                                        if (r < 0)
+                                                return r;
+                                }
+
+                                r = sd_bus_message_close_container(m);
+                        }
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_VARIANT: {
+                        const char *s;
+
+                        s = va_arg(ap, const char*);
+                        if (!s)
+                                return -EINVAL;
+
+                        r = sd_bus_message_open_container(m, SD_BUS_TYPE_VARIANT, s);
+                        if (r < 0)
+                                return r;
+
+                        r = message_append_ap(m, s, ap);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_close_container(m);
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        size_t k;
+
+                        r = signature_element_length(t, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k - 1];
+
+                                memcpy(s, t + 1, k - 2);
+                                s[k - 2] = 0;
+
+                                r = sd_bus_message_open_container(m, *t == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                                if (r < 0)
+                                        return r;
+
+                                t += k - 1;
+
+                                r = message_append_ap(m, s, ap);
+                                if (r < 0)
+                                        return r;
+
+                                r = sd_bus_message_close_container(m);
+                        }
+
+                        break;
+                }
+
+                default:
+                        r = -EINVAL;
+                }
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int sd_bus_message_append(sd_bus_message *m, const char *types, ...) {
+        va_list ap;
+        int r;
+
+        if (!m)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (!types)
+                return -EINVAL;
+
+        va_start(ap, types);
+        r = message_append_ap(m, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+int sd_bus_message_read_type(sd_bus_message *m, char *type, char *element, size_t *length) {
+        return -ENOTSUP;
+}
+
+int sd_bus_message_read_basic(sd_bus_message *m, char type, char element, const void **p, size_t *length) {
+        return -ENOTSUP;
+}
+
+int sd_bus_message_read(sd_bus_message *m, const char *types, ...) {
+        return -ENOTSUP;
+}
+
+int message_parse(sd_bus_message *m) {
+        assert(m);
+
+        if (m->header->version != 1)
+                return -EIO;
+
+        if (m->header->endian != SD_BUS_BIG_ENDIAN &&
+            m->header->endian != SD_BUS_LITTLE_ENDIAN)
+                return -EIO;
+
+        return 0;
+}
+
+static void setup_iovec(sd_bus_message *m) {
+        assert(m);
+        assert(m->sealed);
+
+        m->n_iovec = 0;
+
+        m->iovec[m->n_iovec].iov_base = m->header;
+        m->iovec[m->n_iovec].iov_len = sizeof(*m->header);
+        m->n_iovec++;
+
+        if (m->fields) {
+                m->iovec[m->n_iovec].iov_base = m->fields;
+                m->iovec[m->n_iovec].iov_len = m->header->fields_size;
+                m->n_iovec++;
+
+                if (m->header->fields_size % 8 != 0) {
+                        static const uint8_t padding[7] = { 0, 0, 0, 0, 0, 0, 0 };
+
+                        m->iovec[m->n_iovec].iov_base = (void*) padding;
+                        m->iovec[m->n_iovec].iov_len = 8 - m->header->fields_size % 8;
+                        m->n_iovec++;
+                }
+        }
+
+        if (m->body) {
+                m->iovec[m->n_iovec].iov_base = m->body;
+                m->iovec[m->n_iovec].iov_len = m->header->body_size;
+                m->n_iovec++;
+        }
+}
+
+int message_seal(sd_bus_message *m, uint64_t serial) {
+        int r;
+
+        assert(m);
+
+        if (m->sealed)
+                return -EPERM;
+
+        if (m->n_containers > 0)
+                return -EBADMSG;
+
+        /* If there's a non-trivial signature set, then add it in here */
+        if (!isempty(m->root_container.signature)) {
+                r = message_append_field_signature(m, SD_BUS_MESSAGE_HEADER_SIGNATURE, m->root_container.signature, &m->signature);
+                if (r < 0)
+                        return r;
+        }
+
+        if (m->n_fds > 0) {
+                r = message_append_field_uint32(m, SD_BUS_MESSAGE_HEADER_UNIX_FDS, m->n_fds);
+                if (r < 0)
+                        return r;
+        }
+
+        m->header->serial = serial;
+        m->sealed = true;
+
+        setup_iovec(m);
+
+        return 0;
+}
+
+int sd_bus_message_set_destination(sd_bus_message *m, const char *destination) {
+        if (!m)
+                return -EINVAL;
+        if (!destination)
+                return -EINVAL;
+        if (m->sealed)
+                return -EPERM;
+        if (m->destination)
+                return -EEXIST;
+
+        return message_append_field_string(m, SD_BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &m->destination);
+}
+
+void message_dump(sd_bus_message *m) {
+
+        log_info("Message %p\n"
+                 "\tn_ref=%u\n"
+                 "\tendian=%c\n"
+                 "\ttype=%i\n"
+                 "\tflags=%u\n"
+                 "\tversion=%u\n"
+                 "\tserial=%u\n"
+                 "\tfields_size=%u\n"
+                 "\tbody_size=%u\n"
+                 "\tpath=%s\n"
+                 "\tinterface=%s\n"
+                 "\tmember=%s\n"
+                 "\tdestination=%s\n"
+                 "\tsender=%s\n"
+                 "\tsignature=%s\n"
+                 "\treply_serial=%u\n"
+                 "\terror.name=%s\n"
+                 "\terror.message=%s\n"
+                 "\tsealed=%s\n",
+                 m,
+                 m->n_ref,
+                 m->header->endian,
+                 m->header->type,
+                 m->header->flags,
+                 m->header->version,
+                 BUS_MESSAGE_SERIAL(m),
+                 BUS_MESSAGE_FIELDS_SIZE(m),
+                 BUS_MESSAGE_BODY_SIZE(m),
+                 strna(m->path),
+                 strna(m->interface),
+                 strna(m->member),
+                 strna(m->destination),
+                 strna(m->sender),
+                 strna(m->signature),
+                 m->reply_serial,
+                 strna(m->error.name),
+                 strna(m->error.message),
+                 yes_no(m->sealed));
+}
+
+int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz) {
+        size_t total;
+        unsigned i;
+        void *p, *e;
+
+        assert(m);
+        assert(buffer);
+        assert(sz);
+
+        for (i = 0, total = 0; i < m->n_iovec; i++)
+                total += m->iovec[i].iov_len;
+
+        p = malloc(total);
+        if (!p)
+                return -ENOMEM;
+
+        for (i = 0, e = p; i < m->n_iovec; i++)
+                e = mempcpy(e, m->iovec[i].iov_base, m->iovec[i].iov_len);
+
+        *buffer = p;
+        *sz = total;
+
+        return 0;
+}
diff --git a/src/libsystemd-bus/bus-message.h b/src/libsystemd-bus/bus-message.h
new file mode 100644
index 0000000000..c62659e424
--- /dev/null
+++ b/src/libsystemd-bus/bus-message.h
@@ -0,0 +1,120 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+#include <byteswap.h>
+
+#include "macro.h"
+#include "sd-bus.h"
+
+struct bus_container {
+        char enclosing;
+
+        char *signature;
+        unsigned index;
+
+        uint32_t *array_size;
+};
+
+_packed_ struct bus_header {
+        uint8_t endian;
+        uint8_t type;
+        uint8_t flags;
+        uint8_t version;
+        uint32_t body_size;
+        uint32_t serial;
+        uint32_t fields_size;
+};
+
+struct sd_bus_message {
+        unsigned n_ref;
+
+        uint32_t reply_serial;
+
+        const char *path;
+        const char *interface;
+        const char *member;
+        const char *destination;
+        const char *sender;
+        const char *signature;
+
+        sd_bus_error error;
+
+        uid_t uid;
+        gid_t gid;
+        pid_t pid;
+        pid_t tid;
+
+        bool sealed:1;
+        bool uid_valid:1;
+        bool gid_valid:1;
+        bool free_header:1;
+        bool free_fields:1;
+        bool free_body:1;
+
+        struct bus_header *header;
+        void *fields;
+        void *body;
+
+        uint32_t n_fds;
+        int *fds;
+
+        struct bus_container root_container, *sub_containers;
+        unsigned n_containers;
+
+        struct iovec iovec[4];
+        unsigned n_iovec;
+};
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define BUS_MESSAGE_NEED_BSWAP(m) ((m)->header->endian != SD_BUS_BIG_ENDIAN)
+#else
+#define BUS_MESSAGE_NEED_BSWAP(m) ((m)->header->endian != SD_BUS_LITTLE_ENDIAN)
+#endif
+
+static inline uint32_t BUS_MESSAGE_BSWAP(sd_bus_message *m, uint32_t u) {
+        return BUS_MESSAGE_NEED_BSWAP(m) ? bswap_32(u) : u;
+}
+
+static inline uint32_t BUS_MESSAGE_SERIAL(sd_bus_message *m) {
+        return BUS_MESSAGE_BSWAP(m, m->header->serial);
+}
+
+static inline uint32_t BUS_MESSAGE_BODY_SIZE(sd_bus_message *m) {
+        return BUS_MESSAGE_BSWAP(m, m->header->body_size);
+}
+
+static inline uint32_t BUS_MESSAGE_FIELDS_SIZE(sd_bus_message *m) {
+        return BUS_MESSAGE_BSWAP(m, m->header->fields_size);
+}
+
+static inline void bus_message_unrefp(sd_bus_message **m) {
+        sd_bus_message_unref(*m);
+}
+
+#define _cleanup_bus_message_unref_ __attribute__((cleanup(bus_message_unrefp)))
+
+int message_parse(sd_bus_message *m);
+int message_seal(sd_bus_message *m, uint64_t serial);
+void message_dump(sd_bus_message *m);
+int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz);
diff --git a/src/libsystemd-bus/bus-signature.c b/src/libsystemd-bus/bus-signature.c
new file mode 100644
index 0000000000..db95c8870d
--- /dev/null
+++ b/src/libsystemd-bus/bus-signature.c
@@ -0,0 +1,141 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <util.h>
+
+#include "bus-signature.h"
+#include "bus-type.h"
+
+static int signature_element_length_internal(
+                const char *s,
+                bool allow_dict_entry,
+                size_t *l) {
+
+        int r;
+
+        assert(s);
+
+        if (bus_type_is_basic(*s) || *s == SD_BUS_TYPE_VARIANT) {
+                *l = 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_ARRAY) {
+                size_t t;
+
+                r = signature_element_length_internal(s + 1, true, &t);
+                if (r < 0)
+                        return r;
+
+                *l = t + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_STRUCT_BEGIN) {
+                const char *p = s + 1;
+
+                while (*p != SD_BUS_TYPE_STRUCT_END) {
+                        size_t t;
+
+                        r = signature_element_length_internal(p, false, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                }
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_DICT_ENTRY_BEGIN && allow_dict_entry) {
+                const char *p = s + 1;
+                unsigned n = 0;
+
+                while (*p != SD_BUS_TYPE_DICT_ENTRY_END) {
+                        size_t t;
+
+                        if (n == 0 && !bus_type_is_basic(*p))
+                                return -EINVAL;
+
+                        r = signature_element_length_internal(p, false, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                        n++;
+                }
+
+                if (n != 2)
+                        return -EINVAL;
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+bool signature_is_single(const char *s) {
+        int r;
+        size_t t;
+
+        assert(s);
+
+        r = signature_element_length(s, &t);
+        if (r < 0)
+                return false;
+
+        return s[t] == 0;
+}
+
+bool signature_is_pair(const char *s) {
+        assert(s);
+
+        if (!bus_type_is_basic(*s))
+                return false;
+
+        return signature_is_single(s + 1);
+}
+
+bool signature_is_valid(const char *s, bool allow_dict_entry) {
+        const char *p;
+        int r;
+
+        assert(s);
+
+        p = s;
+        while (*p) {
+                size_t t;
+
+                r = signature_element_length_internal(p, allow_dict_entry, &t);
+                if (r < 0)
+                        return false;
+
+                p += t;
+        }
+
+        return p - s <= 255;
+}
+
+int signature_element_length(const char *s, size_t *l) {
+        return signature_element_length_internal(s, true, l);
+}
diff --git a/src/libsystemd-bus/bus-signature.h b/src/libsystemd-bus/bus-signature.h
new file mode 100644
index 0000000000..4000e0612a
--- /dev/null
+++ b/src/libsystemd-bus/bus-signature.h
@@ -0,0 +1,31 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+#include <sys/types.h>
+
+bool signature_is_single(const char *s);
+bool signature_is_pair(const char *s);
+bool signature_is_valid(const char *s, bool allow_dict_entry);
+
+int signature_element_length(const char *s, size_t *l);
diff --git a/src/libsystemd-bus/bus-type.c b/src/libsystemd-bus/bus-type.c
new file mode 100644
index 0000000000..0557328085
--- /dev/null
+++ b/src/libsystemd-bus/bus-type.c
@@ -0,0 +1,163 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "util.h"
+#include "bus-type.h"
+
+bool bus_type_is_valid(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE,
+                SD_BUS_TYPE_STRING,
+                SD_BUS_TYPE_OBJECT_PATH,
+                SD_BUS_TYPE_SIGNATURE,
+                SD_BUS_TYPE_ARRAY,
+                SD_BUS_TYPE_VARIANT,
+                SD_BUS_TYPE_STRUCT,
+                SD_BUS_TYPE_DICT_ENTRY,
+                SD_BUS_TYPE_UNIX_FD
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_valid_in_signature(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE,
+                SD_BUS_TYPE_STRING,
+                SD_BUS_TYPE_OBJECT_PATH,
+                SD_BUS_TYPE_SIGNATURE,
+                SD_BUS_TYPE_ARRAY,
+                SD_BUS_TYPE_VARIANT,
+                SD_BUS_TYPE_STRUCT_BEGIN,
+                SD_BUS_TYPE_STRUCT_END,
+                SD_BUS_TYPE_DICT_ENTRY_BEGIN,
+                SD_BUS_TYPE_DICT_ENTRY_END,
+                SD_BUS_TYPE_UNIX_FD
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_basic(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE,
+                SD_BUS_TYPE_STRING,
+                SD_BUS_TYPE_OBJECT_PATH,
+                SD_BUS_TYPE_SIGNATURE,
+                SD_BUS_TYPE_UNIX_FD
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_container(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_ARRAY,
+                SD_BUS_TYPE_VARIANT,
+                SD_BUS_TYPE_STRUCT,
+                SD_BUS_TYPE_DICT_ENTRY
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+int bus_type_get_alignment(char c) {
+
+        switch (c) {
+        case SD_BUS_TYPE_BYTE:
+        case SD_BUS_TYPE_SIGNATURE:
+        case SD_BUS_TYPE_VARIANT:
+                return 1;
+
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+                return 2;
+
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+        case SD_BUS_TYPE_ARRAY:
+        case SD_BUS_TYPE_UNIX_FD:
+                return 4;
+
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+        case SD_BUS_TYPE_STRUCT:
+        case SD_BUS_TYPE_STRUCT_BEGIN:
+        case SD_BUS_TYPE_DICT_ENTRY:
+        case SD_BUS_TYPE_DICT_ENTRY_BEGIN:
+                return 8;
+        }
+
+        return -EINVAL;
+}
+
+int bus_type_get_size(char c) {
+
+        switch (c) {
+        case SD_BUS_TYPE_BYTE:
+                return 1;
+
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+                return 2;
+
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_UNIX_FD:
+                return 4;
+
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+                return 8;
+        }
+
+        return -EINVAL;
+}
diff --git a/src/libsystemd-bus/bus-type.h b/src/libsystemd-bus/bus-type.h
new file mode 100644
index 0000000000..e261136084
--- /dev/null
+++ b/src/libsystemd-bus/bus-type.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+
+#include "sd-bus.h"
+#include "sd-bus-protocol.h"
+
+bool bus_type_is_valid(char c);
+bool bus_type_is_valid_in_signature(char c);
+bool bus_type_is_basic(char c);
+bool bus_type_is_container(char c);
+int bus_type_get_alignment(char c);
+int bus_type_get_size(char c);
diff --git a/src/libsystemd-bus/busctl.c b/src/libsystemd-bus/busctl.c
new file mode 100644
index 0000000000..88446fcc7c
--- /dev/null
+++ b/src/libsystemd-bus/busctl.c
@@ -0,0 +1,68 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "sd-bus.h"
+
+int main(int argc, char *argv[]) {
+        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        _cleanup_strv_free_ char **l = NULL;
+        char **i;
+        int r;
+
+        r = bus_open_system(&bus);
+        if (r < 0) {
+                log_error("Failed to connect to bus: %s", strerror(-r));
+                goto fail;
+        }
+
+        r = sd_bus_list_names(bus, &l);
+        if (r < 0) {
+                log_error("Failed to list names: %s", strerror(-r));
+                goto fail;
+        }
+
+        STRV_FOREACH(i, l) {
+                _cleanup_free_ char *owner = NULL;
+                pid_t pid = 0;
+                uid_t uid;
+                bool uid_valid;
+
+                r = sd_bus_get_owner(bus, *i, &owner);
+                if (r == -ENXIO)
+                        continue;
+
+                r = sd_get_owner_pid(bus, *i, &pid);
+                if (r == -ENXIO)
+                        continue;
+
+                r = sd_get_owner_uid(bus, *i, &pid);
+                if (r == -ENXIO)
+                        continue;
+                uid_valid = r >= 0;
+
+                printf("%s (%s) %llu %llu\n", *i, owner, (unsigned long long) pid, (unsigned long long) uid);
+        }
+
+        r = 0;
+
+fail:
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/src/libsystemd-bus/sd-bus-protocol.h b/src/libsystemd-bus/sd-bus-protocol.h
new file mode 100644
index 0000000000..9d7615ff09
--- /dev/null
+++ b/src/libsystemd-bus/sd-bus-protocol.h
@@ -0,0 +1,96 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosdbusprotocolhfoo
+#define foosdbusprotocolhfoo
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+/* Types of message */
+
+#define SD_BUS_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
+
+enum {
+        _SD_BUS_MESSAGE_TYPE_INVALID = 0,
+        SD_BUS_MESSAGE_TYPE_METHOD_CALL,
+        SD_BUS_MESSAGE_TYPE_METHOD_RETURN,
+        SD_BUS_MESSAGE_TYPE_METHOD_ERROR,
+        SD_BUS_MESSAGE_TYPE_SIGNAL,
+        _SD_BUS_MESSAGE_TYPE_MAX
+};
+
+/* Primitive types */
+
+enum {
+        _SD_BUS_TYPE_INVALID         = 0,
+        SD_BUS_TYPE_BYTE             = 'y',
+        SD_BUS_TYPE_BOOLEAN          = 'b',
+        SD_BUS_TYPE_INT16            = 'n',
+        SD_BUS_TYPE_UINT16           = 'q',
+        SD_BUS_TYPE_INT32            = 'i',
+        SD_BUS_TYPE_UINT32           = 'u',
+        SD_BUS_TYPE_INT64            = 'x',
+        SD_BUS_TYPE_UINT64           = 't',
+        SD_BUS_TYPE_DOUBLE           = 'd',
+        SD_BUS_TYPE_STRING           = 's',
+        SD_BUS_TYPE_OBJECT_PATH      = 'o',
+        SD_BUS_TYPE_SIGNATURE        = 'g',
+        SD_BUS_TYPE_UNIX_FD          = 'h',
+        SD_BUS_TYPE_ARRAY            = 'a',
+        SD_BUS_TYPE_VARIANT          = 'v',
+        SD_BUS_TYPE_STRUCT           = 'r', /* not actually used in signatures */
+        SD_BUS_TYPE_STRUCT_BEGIN     = '(',
+        SD_BUS_TYPE_STRUCT_END       = ')',
+        SD_BUS_TYPE_DICT_ENTRY       = 'e', /* not actually used in signatures */
+        SD_BUS_TYPE_DICT_ENTRY_BEGIN = '{',
+        SD_BUS_TYPE_DICT_ENTRY_END   = '}',
+};
+
+/* Endianess */
+
+enum {
+        _SD_BUS_INVALID_ENDIAN = 0,
+        SD_BUS_LITTLE_ENDIAN   = 'l',
+        SD_BUS_BIG_ENDIAN      = 'B'
+};
+
+/* Flags */
+
+enum {
+        SD_BUS_MESSAGE_NO_REPLY_EXPECTED = 1,
+        SD_BUS_MESSAGE_NO_AUTO_START = 2
+};
+
+/* Header fields */
+
+enum {
+        _SD_BUS_MESSAGE_HEADER_INVALID = 0,
+        SD_BUS_MESSAGE_HEADER_PATH,
+        SD_BUS_MESSAGE_HEADER_INTERFACE,
+        SD_BUS_MESSAGE_HEADER_MEMBER,
+        SD_BUS_MESSAGE_HEADER_ERROR_NAME,
+        SD_BUS_MESSAGE_HEADER_REPLY_SERIAL,
+        SD_BUS_MESSAGE_HEADER_DESTINATION,
+        SD_BUS_MESSAGE_HEADER_SENDER,
+        SD_BUS_MESSAGE_HEADER_SIGNATURE,
+        SD_BUS_MESSAGE_HEADER_UNIX_FDS,
+        _SD_BUS_MESSAGE_HEADER_MAX
+};
+
+#endif
diff --git a/src/libsystemd-bus/sd-bus.c b/src/libsystemd-bus/sd-bus.c
new file mode 100644
index 0000000000..d80f09793c
--- /dev/null
+++ b/src/libsystemd-bus/sd-bus.c
@@ -0,0 +1,1437 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <endian.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <sys/poll.h>
+#include <byteswap.h>
+
+#include "util.h"
+#include "macro.h"
+
+#include "sd-bus.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-type.h"
+
+#define WQUEUE_MAX 128
+
+static void bus_free(sd_bus *b) {
+        struct filter_callback *f;
+
+        assert(b);
+
+        if (b->fd >= 0)
+                close_nointr_nofail(b->fd);
+
+        free(b->rbuffer);
+        free(b->rqueue);
+        free(b->wqueue);
+        free(b->unique_name);
+
+        hashmap_free_free(b->reply_callbacks);
+
+        while ((f = b->filter_callbacks)) {
+                LIST_REMOVE(struct filter_callback, callbacks, b->filter_callbacks, f);
+                free(f);
+        }
+
+        free(b);
+}
+
+static sd_bus* bus_new(void) {
+        sd_bus *r;
+
+        r = new0(sd_bus, 1);
+        if (!r)
+                return NULL;
+
+        r->n_ref = 1;
+        r->fd = -1;
+        r->message_version = 1;
+
+        /* 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 r;
+};
+
+static int hello_callback(sd_bus *bus, sd_bus_message *reply, void *userdata) {
+        const char *s;
+        int r;
+
+        assert(bus);
+        assert(reply);
+
+        bus->state = BUS_RUNNING;
+
+        r = sd_bus_message_read(reply, "s", &s);
+        if (r < 0)
+                return r;
+
+        bus->unique_name = strdup(s);
+        if (!bus->unique_name)
+                return -ENOMEM;
+
+        return 1;
+}
+
+static int bus_send_hello(sd_bus *bus) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/",
+                        "org.freedesktop.DBus",
+                        "Hello",
+                        &m);
+        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;
+}
+
+static int bus_start_running(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->send_hello) {
+                bus->state = BUS_HELLO;
+
+                r = bus_send_hello(bus);
+                if (r < 0)
+                        return r;
+        }
+
+        bus->state = BUS_RUNNING;
+
+        return 0;
+}
+
+static int parse_address_key(const char **p, const char *key, char **value) {
+        size_t l, n = 0;
+        const char *a;
+        char *r = NULL;
+
+        assert(p);
+        assert(*p);
+        assert(key);
+        assert(value);
+
+        l = strlen(key);
+        if (!strncmp(*p, key, l) != 0)
+                return 0;
+
+        if ((*p)[l] != '=')
+                return 0;
+
+        if (*value)
+                return -EINVAL;
+
+        a = *p + l + 1;
+        while (*a != ';' && *a != 0) {
+                char c, *t;
+
+                if (*a == '%') {
+                        int x, y;
+
+                        x = unhexchar(a[1]);
+                        if (x < 0) {
+                                free(r);
+                                return x;
+                        }
+
+                        y = unhexchar(a[2]);
+                        if (y < 0) {
+                                free(r);
+                                return y;
+                        }
+
+                        a += 3;
+                        c = (char) ((x << 4) | y);
+                } else
+                        c = *a;
+
+                t = realloc(r, n + 1);
+                if (!t) {
+                        free(r);
+                        return -ENOMEM;
+                }
+
+                r = t;
+                r[n++] = c;
+        }
+
+        *p = a;
+        *value = r;
+        return 1;
+}
+
+static void skip_address_key(const char **p) {
+        assert(p);
+        assert(*p);
+
+        *p += strcspn(*p, ";");
+}
+
+static int bus_parse_next_address(sd_bus *b) {
+        const char *a, *p;
+        _cleanup_free_ char *guid = NULL;
+        int r;
+
+        assert(b);
+
+        if (!b->address)
+                return 0;
+        if (b->address[b->address_index] == 0)
+                return 0;
+
+        a = b->address + b->address_index;
+
+        zero(b->sockaddr);
+        b->sockaddr_size = 0;
+        b->peer = SD_ID128_NULL;
+
+        if (startswith(a, "unix:")) {
+                _cleanup_free_ char *path = NULL, *abstract = NULL;
+
+                p = a + 5;
+                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;
+
+                        r = parse_address_key(&p, "abstract", &abstract);
+                        if (r < 0)
+                                return r;
+                        else if (r > 0)
+                                continue;
+
+                        skip_address_key(&p);
+                }
+
+                if (!path && !abstract)
+                        return -EINVAL;
+
+                if (path && abstract)
+                        return -EINVAL;
+
+                if (path) {
+                        size_t l;
+
+                        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) {
+                        size_t l;
+
+                        l = strlen(path);
+                        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, path, sizeof(b->sockaddr.un.sun_path)-1);
+                        b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
+                }
+
+        } else if (startswith(a, "tcp:")) {
+                _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
+                struct addrinfo hints, *result;
+
+                p = a + 4;
+                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, "host", &host);
+                        if (r < 0)
+                                return r;
+                        else if (r > 0)
+                                continue;
+
+                        r = parse_address_key(&p, "port", &port);
+                        if (r < 0)
+                                return r;
+                        else if (r > 0)
+                                continue;
+
+                        r = parse_address_key(&p, "family", &family);
+                        if (r < 0)
+                                return r;
+                        else if (r > 0)
+                                continue;
+
+                        skip_address_key(&p);
+                }
+
+                if (!host || !port)
+                        return -EINVAL;
+
+                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;
+                }
+
+                r = getaddrinfo(host, port, &hints, &result);
+                if (r == EAI_SYSTEM)
+                        return -errno;
+                else if (r != 0)
+                        return -EADDRNOTAVAIL;
+
+                memcpy(&b->sockaddr, result->ai_addr, result->ai_addrlen);
+                b->sockaddr_size = result->ai_addrlen;
+
+                freeaddrinfo(result);
+        }
+
+        if (guid) {
+                r = sd_id128_from_string(guid, &b->peer);
+                if (r < 0)
+                        return r;
+        }
+
+        b->address_index = p - b->address;
+        return 1;
+}
+
+static void iovec_advance(struct iovec *iov, unsigned *idx, size_t size) {
+
+        while (size > 0) {
+                struct iovec *i = iov + *idx;
+
+                if (i->iov_len > size) {
+                        i->iov_base = (uint8_t*) i->iov_base + size;
+                        i->iov_len -= size;
+                        return;
+                }
+
+                size -= i->iov_len;
+
+                i->iov_base = NULL;
+                i->iov_len = 0;
+
+                (*idx) ++;
+        }
+}
+
+static int bus_write_auth(sd_bus *b) {
+        struct msghdr mh;
+        ssize_t k;
+
+        assert(b);
+        assert(b->state == BUS_AUTHENTICATING);
+
+        if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
+                return 0;
+
+        zero(mh);
+        mh.msg_iov = b->auth_iovec + b->auth_index;
+        mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
+
+        k = sendmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+        if (k < 0)
+                return errno == EAGAIN ? 0 : -errno;
+
+        iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
+
+        return 1;
+}
+
+static int bus_auth_verify(sd_bus *b) {
+        char *e, *f;
+        sd_id128_t peer;
+        unsigned i;
+        int r;
+
+        /* We expect two response lines: "OK", "AGREE_UNIX_FD", and
+         * that's it */
+
+        e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2);
+        if (!e)
+                return 0;
+
+        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;
+
+                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;
+
+        b->can_fds =
+                (f - e == sizeof("\r\nAGREE_UNIX_FD") - 1) &&
+                memcmp(e + 2, "AGREE_UNIX_FD", sizeof("AGREE_UNIX_FD") - 1) == 0;
+
+        if (f + 2 > (char*) b->rbuffer + b->rbuffer_size) {
+                b->rbuffer_size -= (f - (char*) b->rbuffer);
+                memmove(b->rbuffer, f + 2, 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;
+
+        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);
+
+        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;
+
+        b->rbuffer_size += k;
+
+        r = bus_auth_verify(b);
+        if (r != 0)
+                return r;
+
+        return 0;
+}
+
+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";
+
+        char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
+        size_t l;
+
+        assert(b);
+
+        b->state = BUS_AUTHENTICATING;
+
+        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;
+
+        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;
+
+        return bus_write_auth(b);
+}
+
+static int bus_start_connect(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)
+                                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;
+                }
+
+                r = connect(b->fd, &b->sockaddr.sa, b->sockaddr_size);
+                if (r < 0) {
+                        if (errno == EINPROGRESS)
+                                return 0;
+
+                        b->last_connect_error = -errno;
+                        close_nointr_nofail(b->fd);
+                        b->fd = -1;
+                        zero(b->sockaddr);
+                        continue;
+                }
+
+                return bus_start_auth(b);
+        }
+}
+
+int sd_bus_open_system(sd_bus **ret) {
+        const char *e;
+        sd_bus *b;
+        int r;
+
+        if (!ret)
+                return -EINVAL;
+
+        e = getenv("DBUS_SYSTEM_BUS_ADDRESS");
+        if (e) {
+                r = sd_bus_open_address(e, &b);
+                if (r < 0)
+                        return r;
+
+                b->send_hello = true;
+                *ret = b;
+                return r;
+        }
+
+        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;
+        }
+
+        *ret = b;
+        return 0;
+}
+
+int sd_bus_open_user(sd_bus **ret) {
+        const char *e;
+        sd_bus *b;
+        size_t l;
+        int r;
+
+        if (!ret)
+                return -EINVAL;
+
+        e = getenv("DBUS_SESSION_BUS_ADDRESS");
+        if (e) {
+                r = sd_bus_open_address(e, &b);
+                if (r < 0)
+                        return r;
+
+                b->send_hello = true;
+                *ret = b;
+                return r;
+        }
+
+        e = getenv("XDG_RUNTIME_DIR");
+        if (!e)
+                return -ENOENT;
+
+        l = strlen(e);
+        if (l + 4 > sizeof(b->sockaddr.un.sun_path))
+                return -E2BIG;
+
+        b = bus_new();
+        if (!b)
+                return -ENOMEM;
+
+        b->send_hello = true;
+
+        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;
+
+        r = bus_start_connect(b);
+        if (r < 0) {
+                bus_free(b);
+                return r;
+        }
+
+        *ret = b;
+        return 0;
+}
+
+int sd_bus_open_address(const char *address, sd_bus **ret) {
+        sd_bus *b;
+        int r;
+
+        if (!address)
+                return -EINVAL;
+        if (!ret)
+                return -EINVAL;
+
+        b = bus_new();
+        if (!b)
+                return -ENOMEM;
+
+        b->address = strdup(address);
+        if (!b->address) {
+                bus_free(b);
+                return -ENOMEM;
+        }
+
+        r = bus_start_connect(b);
+        if (r < 0) {
+                bus_free(b);
+                return r;
+        }
+
+        *ret = b;
+        return 0;
+}
+
+int sd_bus_open_fd(int fd, sd_bus **ret) {
+        sd_bus *b;
+        int r;
+
+        if (fd < 0)
+                return -EINVAL;
+        if (!ret)
+                return -EINVAL;
+
+        b = bus_new();
+        if (!b)
+                return -ENOMEM;
+
+        b->fd = fd;
+        fd_nonblock(b->fd, true);
+        fd_cloexec(b->fd, true);
+
+        r = bus_start_auth(b);
+        if (r < 0) {
+                bus_free(b);
+                return r;
+        }
+
+        *ret = b;
+        return 0;
+}
+
+void sd_bus_close(sd_bus *bus) {
+        if (!bus)
+                return;
+        if (bus->fd < 0)
+                return;
+
+        close_nointr_nofail(bus->fd);
+        bus->fd = -1;
+}
+
+sd_bus *sd_bus_ref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        assert(bus->n_ref > 0);
+
+        bus->n_ref++;
+        return bus;
+}
+
+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)
+                bus_free(bus);
+
+        return NULL;
+}
+
+int sd_bus_is_running(sd_bus *bus) {
+        if (!bus)
+                return -EINVAL;
+
+        if (bus->fd < 0)
+                return -ENOTCONN;
+
+        return bus->state == BUS_RUNNING;
+}
+
+int sd_bus_can_send(sd_bus *bus, char type) {
+
+        if (!bus)
+                return -EINVAL;
+
+        if (type == SD_BUS_TYPE_UNIX_FD)
+                return bus->can_fds;
+
+        return bus_type_is_valid(type);
+}
+
+static int bus_seal_message(sd_bus *b, sd_bus_message *m) {
+        assert(m);
+
+        if (m->sealed)
+                return 0;
+
+        return 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;
+
+        assert(bus);
+        assert(m);
+        assert(idx);
+
+        n = m->n_iovec * sizeof(struct iovec);
+        iov = alloca(n);
+        memcpy(iov, m->iovec, n);
+
+        j = 0;
+        iovec_advance(iov, &j, *idx);
+
+        zero(mh);
+        mh.msg_iov = iov;
+        mh.msg_iovlen = m->n_iovec;
+
+        k = sendmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+        if (k < 0)
+                return -errno;
+
+        *idx += (size_t) k;
+        iovec_advance(iov, &j, *idx);
+
+        return j > m->n_iovec;
+}
+
+static int message_read_need(sd_bus *bus, size_t *need) {
+        uint32_t a, b;
+        uint8_t e;
+
+        assert(bus);
+        assert(need);
+
+        if (bus->rbuffer_size <= sizeof(struct bus_header)) {
+                *need = sizeof(struct bus_header);
+                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 -EIO;
+
+        *need = sizeof(struct bus_header) + ALIGN_TO(a, 8) + b;
+        return 0;
+}
+
+static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
+        sd_bus_message *t;
+        void *b = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(bus->rbuffer_size >= size);
+
+        t = new0(sd_bus_message, 1);
+        if (!t)
+                return -ENOMEM;
+
+        if (bus->rbuffer_size > size) {
+                b = memdup((const uint8_t*) bus->rbuffer + size, bus->rbuffer_size - size);
+                if (!b) {
+                        free(t);
+                        return -ENOMEM;
+                }
+        }
+
+        t->n_ref = 1;
+
+        t->header = bus->rbuffer;
+        t->free_header = true;
+
+        t->fields = (uint8_t*) bus->rbuffer + sizeof(struct bus_header);
+        t->body = (uint8_t*) bus->rbuffer + sizeof(struct bus_header) + ALIGN_TO(BUS_MESSAGE_BODY_SIZE(t), 8);
+
+        bus->rbuffer = b;
+        bus->rbuffer_size -= size;
+
+        r = 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;
+
+        r = bus_seal_message(bus, m);
+        if (r < 0)
+                return r;
+
+        if (bus->wqueue_size <= 0) {
+                size_t idx = 0;
+
+                r = message_write(bus, m, &idx);
+                if (r < 0) {
+                        sd_bus_close(bus);
+                        return r;
+                } else if (r == 0)  {
+                        /* Wasn't fully written. So let's remember how
+                         * much was written. Note that the first entry
+                         * of the wqueue array is always allocated so
+                         * that we always can remember how much was
+                         * written. */
+                        bus->wqueue[0] = sd_bus_message_ref(m);
+                        bus->wqueue_size = 1;
+                        bus->windex = idx;
+                }
+        } else {
+                sd_bus_message **q;
+
+                /* Just append it to the queue. */
+
+                if (bus->wqueue_size >= WQUEUE_MAX)
+                        return -ENOBUFS;
+
+                q = realloc(bus->wqueue, sizeof(sd_bus_message*) * (bus->wqueue_size + 1));
+                if (!q)
+                        return -ENOMEM;
+
+                bus->wqueue = q;
+                q[bus->wqueue_size ++] = sd_bus_message_ref(m);
+        }
+
+        if (serial)
+                *serial = BUS_MESSAGE_SERIAL(m);
+
+        return 0;
+}
+
+static usec_t calc_elapse(uint64_t usec) {
+        if (usec == (uint64_t) -1)
+                return 0;
+
+        if (usec == 0)
+                usec = SD_BUS_DEFAULT_TIMEOUT;
+
+        return now(CLOCK_MONOTONIC) + usec;
+}
+
+int sd_bus_send_with_reply(
+                sd_bus *bus,
+                sd_bus_message *m,
+                sd_message_handler_t callback,
+                void *userdata,
+                uint64_t usec,
+                uint64_t *serial) {
+
+        struct reply_callback *c;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        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;
+
+        r = bus_seal_message(bus, m);
+        if (r < 0)
+                return r;
+
+        c = new(struct reply_callback, 1);
+        if (!c)
+                return -ENOMEM;
+
+        c->callback = callback;
+        c->userdata = userdata;
+        c->serial = BUS_MESSAGE_SERIAL(m);
+        c->timeout = calc_elapse(usec);
+
+        r = hashmap_put(bus->reply_callbacks, &c->serial, c);
+        if (r < 0) {
+                free(c);
+                return r;
+        }
+
+        r = sd_bus_send(bus, m, serial);
+        if (r < 0) {
+                hashmap_remove(bus->reply_callbacks, &c->serial);
+                free(c);
+                return r;
+        }
+
+        return r;
+}
+
+int sd_bus_send_with_reply_cancel(sd_bus *bus, uint64_t serial) {
+        struct reply_callbacks *c;
+
+        if (!bus)
+                return -EINVAL;
+        if (serial == 0)
+                return -EINVAL;
+
+        c = hashmap_remove(bus->reply_callbacks, &serial);
+        if (!c)
+                return 0;
+
+        free(c);
+        return 1;
+}
+
+int sd_bus_send_with_reply_and_block(
+                sd_bus *bus,
+                sd_bus_message *m,
+                uint64_t usec,
+                sd_bus_error *error,
+                sd_bus_message **reply) {
+
+        int r;
+        usec_t timeout;
+        uint64_t serial;
+        bool room = false;
+
+        if (!bus)
+                return -EINVAL;
+        if (!bus->fd < 0)
+                return -ENOTCONN;
+        if (!m)
+                return -EINVAL;
+        if (!m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return -EINVAL;
+        if (sd_bus_error_is_set(error))
+                return -EINVAL;
+
+        r = sd_bus_send(bus, m, &serial);
+        if (r < 0)
+                return r;
+
+        timeout = calc_elapse(usec);
+
+        for (;;) {
+                usec_t left;
+                sd_bus_message *incoming;
+
+                if (!room) {
+                        sd_bus_message **q;
+
+                        /* Make sure there's room for queuing this
+                         * locally, before we read the message */
+
+                        q = realloc(bus->rqueue, (bus->rqueue_size + 1) * sizeof(sd_bus_message*));
+                        if (!q)
+                                return -ENOMEM;
+
+                        bus->rqueue = q;
+                        room = true;
+                }
+
+                r = message_read(bus, &incoming);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        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_TYPE_METHOD_ERROR) {
+                                        int k;
+
+                                        r = sd_bus_error_copy(error, &incoming->error);
+                                        if (r < 0) {
+                                                sd_bus_message_unref(incoming);
+                                                return r;
+                                        }
+
+                                        k = bus_error_to_errno(&incoming->error);
+                                        sd_bus_message_unref(incoming);
+                                        return k;
+                                }
+
+                                sd_bus_message_unref(incoming);
+                                return -EIO;
+                        }
+
+                        /* There's already guaranteed to be room for
+                         * this, so need to resize things here */
+                        bus->rqueue[bus->rqueue_size ++] = incoming;
+                        room = false;
+
+                        /* Try to read more, right-away */
+                        continue;
+                }
+
+                if (timeout > 0) {
+                        usec_t n;
+
+                        n = now(CLOCK_MONOTONIC);
+                        if (n >= timeout)
+                                return -ETIMEDOUT;
+
+                        left = timeout - n;
+                } else
+                        left = (uint64_t) -1;
+
+                r = sd_bus_wait(bus, left);
+                if (r < 0)
+                        return r;
+
+                r = dispatch_wqueue(bus);
+                if (r < 0)
+                        return r;
+        }
+}
+
+int sd_bus_get_fd(sd_bus *bus) {
+        if (!bus)
+                return -EINVAL;
+
+        if (bus->fd < 0)
+                return -EINVAL;
+
+        return bus->fd;
+}
+
+int sd_bus_get_events(sd_bus *bus) {
+        int flags = 0;
+
+        if (!bus)
+                return -EINVAL;
+
+        if (bus->fd < 0)
+                return -EINVAL;
+
+        if (bus->state == BUS_OPENING)
+                flags |= POLLOUT;
+        else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
+                if (bus->rqueue_size <= 0)
+                        flags |= POLLIN;
+                if (bus->wqueue_size > 0)
+                        flags |= POLLOUT;
+        }
+
+        return flags;
+}
+
+int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
+        sd_bus_message *m;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (bus->fd < 0)
+                return -ENOTCONN;
+
+        if (bus->state == BUS_OPENING) {
+                struct pollfd p;
+
+                zero(p);
+                p.fd = bus->fd;
+                p.events = POLLOUT;
+
+                r = poll(&p, 1, 0);
+                if (r < 0)
+                        return -errno;
+
+                if (p.revents & (POLLOUT|POLLERR|POLLHUP)) {
+                        int error;
+                        socklen_t slen = sizeof(error);
+
+                        r = getsockopt(bus->fd, SOL_SOCKET, SO_ERROR, &error, &slen);
+                        if (r < 0)
+                                return -errno;
+
+                        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);
+
+                        /* Try next address */
+                        return bus_start_connect(bus);
+                }
+
+                return 0;
+
+        } else if (bus->state == BUS_AUTHENTICATING) {
+
+                r = bus_write_auth(bus);
+                if (r < 0)
+                        return r;
+
+                r = bus_read_auth(bus);
+                if (r <= 0)
+                        return r;
+
+                return bus_start_running(bus);
+
+        } else if (bus->state == BUS_RUNNING || bus->state == BUS_HELLO) {
+                struct filter_callback *l;
+
+                r = dispatch_wqueue(bus);
+                if (r < 0)
+                        return r;
+
+                r = dispatch_rqueue(bus, &m);
+                if (r <= 0)
+                        return r;
+
+                if (m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_CALL || m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_RETURN) {
+                        struct reply_callback *c;
+
+                        c = hashmap_remove(bus->reply_callbacks, &m->reply_serial);
+                        if (c) {
+                                r = c->callback(bus, m, c->userdata);
+                                free(c);
+
+                                if (r != 0) {
+                                        sd_bus_message_unref(m);
+                                        return r < 0 ? r : 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;
+                        }
+                }
+
+                if (ret) {
+                        *ret = m;
+                        return 1;
+                }
+
+                sd_bus_message_unref(m);
+                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;
+
+        zero(p);
+        p.fd = bus->fd;
+        p.events = e;
+
+        r = ppoll(&p, 1, timeout_usec == (uint64_t) -1 ? NULL : timespec_store(&ts, timeout_usec), NULL);
+        if (r < 0)
+                return -EINVAL;
+
+        return r;
+}
+
+int sd_bus_flush(sd_bus *bus) {
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (bus->fd < 0)
+                return -ENOTCONN;
+
+        if (bus->state == BUS_RUNNING && bus->wqueue_size <= 0)
+                return 0;
+
+        for (;;) {
+                r = dispatch_wqueue(bus);
+                if (r < 0)
+                        return r;
+
+                if (bus->state == BUS_RUNNING && bus->wqueue_size <= 0)
+                        return 0;
+
+                r = sd_bus_wait(bus, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
+int sd_bus_add_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata) {
+        struct filter_callback *f;
+
+        if (!bus)
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+
+        f = new(struct filter_callback, 1);
+        if (!f)
+                return -ENOMEM;
+        f->callback = callback;
+        f->userdata = userdata;
+
+        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) {
+        struct filter_callback *f;
+
+        if (!bus)
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+
+        LIST_FOREACH(callbacks, f, bus->filter_callbacks) {
+                if (f->callback == callback && f->userdata == userdata) {
+                        LIST_REMOVE(struct filter_callback, callbacks, bus->filter_callbacks, f);
+                        free(f);
+                        return 1;
+                }
+        }
+
+        return 0;
+}
diff --git a/src/libsystemd-bus/sd-bus.h b/src/libsystemd-bus/sd-bus.h
new file mode 100644
index 0000000000..6d53d5afd8
--- /dev/null
+++ b/src/libsystemd-bus/sd-bus.h
@@ -0,0 +1,135 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosdbushfoo
+#define foosdbushfoo
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+#include <sys/types.h>
+
+#include "sd-bus-protocol.h"
+
+typedef struct sd_bus sd_bus;
+typedef struct sd_bus_message sd_bus_message;
+
+typedef struct {
+        const char *name;
+        const char *message;
+        int need_free;
+} sd_bus_error;
+
+typedef int (*sd_message_handler_t)(sd_bus *bus, sd_bus_message *m, void *userdata);
+
+/* Connections */
+
+int sd_bus_open_system(sd_bus **ret);
+int sd_bus_open_user(sd_bus **ret);
+int sd_bus_open_address(const char *address, sd_bus **ret);
+int sd_bus_open_fd(int fd, sd_bus **ret);
+void sd_bus_close(sd_bus *bus);
+
+sd_bus *sd_bus_ref(sd_bus *bus);
+sd_bus *sd_bus_unref(sd_bus *bus);
+
+int sd_bus_is_running(sd_bus *bus);
+int sd_bus_can_send(sd_bus *bus, char type);
+
+int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial);
+int sd_bus_send_with_reply(sd_bus *bus, sd_bus_message *m, sd_message_handler_t callback, void *userdata, uint64_t usec, uint64_t *serial);
+int sd_bus_send_with_reply_cancel(sd_bus *bus, uint64_t serial);
+int sd_bus_send_with_reply_and_block(sd_bus *bus, sd_bus_message *m, uint64_t usec, sd_bus_error *error, sd_bus_message **r);
+
+int sd_bus_get_fd(sd_bus *bus);
+int sd_bus_get_events(sd_bus *bus);
+int sd_bus_process(sd_bus *bus, sd_bus_message **r);
+int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec);
+int sd_bus_flush(sd_bus *bus);
+
+int sd_bus_add_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata);
+int sd_bus_remove_filter(sd_bus *bus, sd_message_handler_t callback, void *userdata);
+
+/* Message object */
+
+int sd_bus_message_new_signal(sd_bus *bus, const char *path, const char *interface, const char *member, sd_bus_message **m);
+int sd_bus_message_new_method_call(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *member, sd_bus_message **m);
+int sd_bus_message_new_method_return(sd_bus *bus, sd_bus_message *call, sd_bus_message **m);
+int sd_bus_message_new_method_error(sd_bus *bus, sd_bus_message *call, const sd_bus_error *e, sd_bus_message **m);
+
+sd_bus_message* sd_bus_message_ref(sd_bus_message *m);
+sd_bus_message* sd_bus_message_unref(sd_bus_message *m);
+
+int sd_bus_message_get_type(sd_bus_message *m, uint8_t *type);
+int sd_bus_message_get_serial(sd_bus_message *m, uint64_t *serial);
+int sd_bus_message_get_reply_serial(sd_bus_message *m, uint64_t *serial);
+int sd_bus_message_get_no_reply(sd_bus_message *m);
+
+const char *sd_bus_message_get_path(sd_bus_message *m);
+const char *sd_bus_message_get_interface(sd_bus_message *m);
+const char *sd_bus_message_get_member(sd_bus_message *m);
+const char *sd_bus_message_get_destination(sd_bus_message *m);
+const char *sd_bus_message_get_sender(sd_bus_message *m);
+const sd_bus_error *sd_bus_message_get_error(sd_bus_message *m);
+
+int sd_bus_message_get_uid(sd_bus_message *m, uid_t *uid);
+int sd_bus_message_get_gid(sd_bus_message *m, gid_t *gid);
+int sd_bus_message_get_pid(sd_bus_message *m, pid_t *pid);
+int sd_bus_message_get_tid(sd_bus_message *m, pid_t *tid);
+
+int sd_bus_message_is_signal(sd_bus_message *m, const char *interface, const char *member);
+int sd_bus_message_is_method_call(sd_bus_message *m, const char *interface, const char *member);
+int sd_bus_message_is_method_error(sd_bus_message *m, const char *name);
+
+int sd_bus_message_set_no_reply(sd_bus_message *m, int b);
+int sd_bus_message_set_destination(sd_bus_message *m, const char *destination);
+
+int sd_bus_message_append(sd_bus_message *m, const char *types, ...);
+int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p);
+int sd_bus_message_open_container(sd_bus_message *m, char type, const char *contents);
+int sd_bus_message_close_container(sd_bus_message *m);
+
+int sd_bus_message_read_type(sd_bus_message *m, char *type, char *element, size_t *length);
+int sd_bus_message_read_basic(sd_bus_message *m, char type, char element, const void **p, size_t *length);
+int sd_bus_message_read(sd_bus_message *m, const char *types, ...);
+
+/* Bus management */
+
+const char *sd_bus_get_unique_name(sd_bus *bus);
+int sd_bus_request_name(sd_bus *bus, const char *name, int flags);
+int sd_bus_release_name(sd_bus *bus, const char *name);
+int sd_bus_list_names(sd_bus *bus, char ***l);
+int sd_bus_get_owner(sd_bus *bus, const char *name, char **owner);
+int sd_bus_get_owner_uid(sd_bus *bus, const char *name, uid_t *uid);
+int sd_bus_get_owner_pid(sd_bus *bus, const char *name, pid_t *pid);
+int sd_bus_add_match(sd_bus *bus, const char *match);
+int sd_bus_remove_match(sd_bus *bus, const char *match);
+
+/* Error objects */
+
+#define SD_BUS_ERROR_INIT (NULL, NULL, false)
+
+void sd_bus_error_free(sd_bus_error *e);
+int sd_bus_error_set(sd_bus_error *e, const char *name, const char *format, ...);
+void sd_bus_error_set_const(sd_bus_error *e, const char *name, const char *message);
+int sd_bus_error_copy(sd_bus_error *dest, const sd_bus_error *e);
+int sd_bus_error_is_set(const sd_bus_error *e);
+int sd_bus_error_has_name(const sd_bus_error *e, const char *name);
+
+#endif
diff --git a/src/libsystemd-bus/test-bus-marshal.c b/src/libsystemd-bus/test-bus-marshal.c
new file mode 100644
index 0000000000..08364ef48b
--- /dev/null
+++ b/src/libsystemd-bus/test-bus-marshal.c
@@ -0,0 +1,129 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <stdlib.h>
+#include <byteswap.h>
+
+#ifdef HAVE_GLIB
+#include <gio/gio.h>
+#endif
+
+#include <dbus.h>
+
+#include "log.h"
+#include "util.h"
+
+#include "sd-bus.h"
+#include "bus-message.h"
+
+int main(int argc, char *argv[]) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+        const char *x, *y, *z, *a, *b, *c;
+        uint8_t u, v;
+        void *buffer = NULL;
+        size_t sz;
+        char *h;
+
+        r = sd_bus_message_new_method_call(NULL, "foobar.waldo", "/", "foobar.waldo", "Piep", &m);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "s", "a string");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "as", 2, "string #1", "string #2");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "sass", "foobar", 5, "foo", "bar", "waldo", "piep", "pap", "after");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "a{yv}", 2, 3, "s", "foo", 5, "s", "waldo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "ba(ss)", 255, 3, "aaa", "1", "bbb", "2", "ccc", "3");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_basic(m, 's', "foobar");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_basic(m, 's', "waldo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_close_container(m);
+        assert_se(r >= 0);
+
+        r = message_seal(m, 4711);
+        assert_se(r >= 0);
+
+        message_dump(m);
+
+        r = bus_message_get_blob(m, &buffer, &sz);
+        assert_se(r >= 0);
+
+        h = hexmem(buffer, sz);
+        assert_se(h);
+
+        log_info("message size = %lu, contents =\n%s", (unsigned long) sz, h);
+        free(h);
+
+#ifdef HAVE_GLIB
+        {
+                GDBusMessage *g;
+                char *p;
+
+                g_type_init();
+
+                g = g_dbus_message_new_from_blob(buffer, sz, 0, NULL);
+                p = g_dbus_message_print(g, 0);
+                log_info("%s", p);
+                g_free(p);
+                g_object_unref(g);
+        }
+#endif
+
+        {
+                DBusMessage *w;
+                DBusError error;
+
+                dbus_error_init(&error);
+
+                w = dbus_message_demarshal(buffer, sz, &error);
+                if (!w) {
+                        log_error("%s", error.message);
+                } else
+                        dbus_message_unref(w);
+        }
+
+        free(buffer);
+
+        /* r = sd_bus_message_read(m, "sas", &x, 5, &y, &z, &a, &b, &c); */
+        /* assert_se(r >= 0); */
+
+        /* r = sd_bus_message_read(m, "a{yv}", 2, */
+        /*                        &u, "s", &x, */
+        /*                        &v, "s", &y); */
+
+        return 0;
+}
diff --git a/src/libsystemd-bus/test-bus-signature.c b/src/libsystemd-bus/test-bus-signature.c
new file mode 100644
index 0000000000..4310d62e0a
--- /dev/null
+++ b/src/libsystemd-bus/test-bus-signature.c
@@ -0,0 +1,74 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "log.h"
+#include "bus-signature.h"
+
+int main(int argc, char *argv[]) {
+
+        assert_se(signature_is_single("y"));
+        assert_se(signature_is_single("u"));
+        assert_se(signature_is_single("v"));
+        assert_se(signature_is_single("as"));
+        assert_se(signature_is_single("(ss)"));
+        assert_se(signature_is_single("()"));
+        assert_se(signature_is_single("(()()()()())"));
+        assert_se(signature_is_single("(((())))"));
+        assert_se(signature_is_single("((((s))))"));
+        assert_se(signature_is_single("{ss}"));
+        assert_se(signature_is_single("a{ss}"));
+        assert_se(!signature_is_single("uu"));
+        assert_se(!signature_is_single(""));
+        assert_se(!signature_is_single("("));
+        assert_se(!signature_is_single(")"));
+        assert_se(!signature_is_single("())"));
+        assert_se(!signature_is_single("((())"));
+        assert_se(!signature_is_single("{)"));
+        assert_se(!signature_is_single("{}"));
+        assert_se(!signature_is_single("{sss}"));
+        assert_se(!signature_is_single("{s}"));
+        assert_se(!signature_is_single("{ass}"));
+        assert_se(!signature_is_single("a}"));
+
+        assert_se(signature_is_pair("yy"));
+        assert_se(signature_is_pair("ss"));
+        assert_se(signature_is_pair("sas"));
+        assert_se(signature_is_pair("sv"));
+        assert_se(signature_is_pair("sa(vs)"));
+        assert_se(!signature_is_pair(""));
+        assert_se(!signature_is_pair("va"));
+        assert_se(!signature_is_pair("sss"));
+        assert_se(!signature_is_pair("{s}ss"));
+
+        assert_se(signature_is_valid("ssa{ss}sssub", true));
+        assert_se(signature_is_valid("ssa{ss}sssub", false));
+        assert_se(signature_is_valid("{ss}", true));
+        assert_se(!signature_is_valid("{ss}", false));
+        assert_se(signature_is_valid("", true));
+        assert_se(signature_is_valid("", false));
+
+        assert_se(signature_is_valid("sssusa(uuubbba(uu)uuuu)a{u(uuuvas)}", false));
+
+        return 0;
+}