Adding upstream version 252.22.upstream/252.22

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

1 files changed, 4669 insertions, 0 deletions

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
new file mode 100644
index 0000000..0fe80af
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -0,0 +1,4669 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-signature.h"
+#include "bus-type.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "memfd-util.h"
+#include "memory-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "utf8.h"
+
+static int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored);
+static int message_parse_fields(sd_bus_message *m);
+
+static void *adjust_pointer(const void *p, void *old_base, size_t sz, void *new_base) {
+
+        if (!p)
+                return NULL;
+
+        if (old_base == new_base)
+                return (void*) p;
+
+        if ((uint8_t*) p < (uint8_t*) old_base)
+                return (void*) p;
+
+        if ((uint8_t*) p >= (uint8_t*) old_base + sz)
+                return (void*) p;
+
+        return (uint8_t*) new_base + ((uint8_t*) p - (uint8_t*) old_base);
+}
+
+static void message_free_part(sd_bus_message *m, struct bus_body_part *part) {
+        assert(m);
+        assert(part);
+
+        if (part->memfd >= 0) {
+                /* erase if requested, but only if the memfd is not sealed yet, i.e. is writable */
+                if (m->sensitive && !m->sealed)
+                        explicit_bzero_safe(part->data, part->size);
+
+                close_and_munmap(part->memfd, part->mmap_begin, part->mapped);
+        } else if (part->munmap_this)
+                /* We don't erase sensitive data here, since the data is memory mapped from someone else, and
+                 * we just don't know if it's OK to write to it */
+                munmap(part->mmap_begin, part->mapped);
+        else {
+                /* Erase this if that is requested. Since this is regular memory we know we can write it. */
+                if (m->sensitive)
+                        explicit_bzero_safe(part->data, part->size);
+
+                if (part->free_this)
+                        free(part->data);
+        }
+
+        if (part != &m->body)
+                free(part);
+}
+
+static void message_reset_parts(sd_bus_message *m) {
+        struct bus_body_part *part;
+
+        assert(m);
+
+        part = &m->body;
+        while (m->n_body_parts > 0) {
+                struct bus_body_part *next = part->next;
+                message_free_part(m, part);
+                part = next;
+                m->n_body_parts--;
+        }
+
+        m->body_end = NULL;
+
+        m->cached_rindex_part = NULL;
+        m->cached_rindex_part_begin = 0;
+}
+
+static struct bus_container *message_get_last_container(sd_bus_message *m) {
+        assert(m);
+
+        if (m->n_containers == 0)
+                return &m->root_container;
+
+        assert(m->containers);
+        return m->containers + m->n_containers - 1;
+}
+
+static void message_free_last_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        c = message_get_last_container(m);
+
+        free(c->signature);
+        free(c->peeked_signature);
+
+        /* Move to previous container, but not if we are on root container */
+        if (m->n_containers > 0)
+                m->n_containers--;
+}
+
+static void message_reset_containers(sd_bus_message *m) {
+        assert(m);
+
+        while (m->n_containers > 0)
+                message_free_last_container(m);
+
+        m->containers = mfree(m->containers);
+        m->root_container.index = 0;
+}
+
+static sd_bus_message* message_free(sd_bus_message *m) {
+        assert(m);
+
+        message_reset_parts(m);
+
+        if (m->free_header)
+                free(m->header);
+
+        /* Note that we don't unref m->bus here. That's already done by sd_bus_message_unref() as each user
+         * reference to the bus message also is considered a reference to the bus connection itself. */
+
+        if (m->free_fds) {
+                close_many(m->fds, m->n_fds);
+                free(m->fds);
+        }
+
+        if (m->iovec != m->iovec_fixed)
+                free(m->iovec);
+
+        message_reset_containers(m);
+        assert(m->n_containers == 0);
+        message_free_last_container(m);
+
+        bus_creds_done(&m->creds);
+        return mfree(m);
+}
+
+static void *message_extend_fields(sd_bus_message *m, size_t sz, bool add_offset) {
+        void *op, *np;
+        size_t old_size, new_size, start;
+
+        assert(m);
+
+        if (m->poisoned)
+                return NULL;
+
+        old_size = sizeof(struct bus_header) + m->fields_size;
+        start = ALIGN8(old_size);
+        new_size = start + sz;
+
+        if (new_size < start || new_size > UINT32_MAX)
+                goto poison;
+
+        if (old_size == new_size)
+                return (uint8_t*) m->header + old_size;
+
+        if (m->free_header) {
+                np = realloc(m->header, ALIGN8(new_size));
+                if (!np)
+                        goto poison;
+        } else {
+                /* Initially, the header is allocated as part of
+                 * the sd_bus_message itself, let's replace it by
+                 * dynamic data */
+
+                np = malloc(ALIGN8(new_size));
+                if (!np)
+                        goto poison;
+
+                memcpy(np, m->header, sizeof(struct bus_header));
+        }
+
+        /* Zero out padding */
+        if (start > old_size)
+                memzero((uint8_t*) np + old_size, start - old_size);
+
+        op = m->header;
+        m->header = np;
+        m->fields_size = new_size - sizeof(struct bus_header);
+
+        /* Adjust quick access pointers */
+        m->path = adjust_pointer(m->path, op, old_size, m->header);
+        m->interface = adjust_pointer(m->interface, op, old_size, m->header);
+        m->member = adjust_pointer(m->member, op, old_size, m->header);
+        m->destination = adjust_pointer(m->destination, op, old_size, m->header);
+        m->sender = adjust_pointer(m->sender, op, old_size, m->header);
+        m->error.name = adjust_pointer(m->error.name, op, old_size, m->header);
+
+        m->free_header = true;
+
+        if (add_offset) {
+                if (m->n_header_offsets >= ELEMENTSOF(m->header_offsets))
+                        goto poison;
+
+                m->header_offsets[m->n_header_offsets++] = new_size - sizeof(struct bus_header);
+        }
+
+        return (uint8_t*) np + start;
+
+poison:
+        m->poisoned = true;
+        return NULL;
+}
+
+static int message_append_field_string(
+                sd_bus_message *m,
+                uint64_t h,
+                char type,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        /* dbus doesn't allow strings over 32bit */
+        l = strlen(s);
+        if (l > UINT32_MAX)
+                return -EINVAL;
+
+        /* Signature "(yv)" where the variant contains "s" */
+
+        /* (field id byte + (signature length + signature 's' + NUL) + (string length + string + NUL)) */
+        p = message_extend_fields(m, 4 + 4 + l + 1, false);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = (uint8_t) h;
+        p[1] = 1;
+        p[2] = type;
+        p[3] = 0;
+
+        ((uint32_t*) p)[1] = l;
+        memcpy(p + 8, s, l + 1);
+
+        if (ret)
+                *ret = (char*) p + 8;
+
+        return 0;
+}
+
+static int message_append_field_signature(
+                sd_bus_message *m,
+                uint64_t h,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        /* dbus doesn't allow signatures over 8bit */
+        l = strlen(s);
+        if (l > SD_BUS_MAXIMUM_SIGNATURE_LENGTH)
+                return -EINVAL;
+
+        /* Signature "(yv)" where the variant contains "g" */
+
+        /* (field id byte + (signature length + signature 'g' + NUL) + (string length + string + NUL)) */
+        p = message_extend_fields(m, 4 + 1 + l + 1, false);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = (uint8_t) 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, uint64_t h, uint32_t x) {
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        /* (field id byte + (signature length + signature 'u' + NUL) + value) */
+        p = message_extend_fields(m, 4 + 4, false);
+        if (!p)
+                return -ENOMEM;
+
+        p[0] = (uint8_t) h;
+        p[1] = 1;
+        p[2] = 'u';
+        p[3] = 0;
+
+        ((uint32_t*) p)[1] = x;
+
+        return 0;
+}
+
+static int message_append_reply_cookie(sd_bus_message *m, uint64_t cookie) {
+        assert(m);
+
+        /* 64bit cookies are not supported */
+        if (cookie > UINT32_MAX)
+                return -EOPNOTSUPP;
+
+        return message_append_field_uint32(m, BUS_MESSAGE_HEADER_REPLY_SERIAL, (uint32_t) cookie);
+}
+
+static int message_from_header(
+                sd_bus *bus,
+                void *buffer,
+                size_t message_size,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                sd_bus_message **ret) {
+
+        _cleanup_free_ sd_bus_message *m = NULL;
+        struct bus_header *h;
+        size_t a, label_sz = 0; /* avoid false maybe-uninitialized warning */
+
+        assert(bus);
+        assert(buffer || message_size <= 0);
+        assert(fds || n_fds <= 0);
+        assert(ret);
+
+        if (message_size < sizeof(struct bus_header))
+                return -EBADMSG;
+
+        h = buffer;
+        if (!IN_SET(h->version, 1, 2))
+                return -EBADMSG;
+
+        if (h->type == _SD_BUS_MESSAGE_TYPE_INVALID)
+                return -EBADMSG;
+
+        if (!IN_SET(h->endian, BUS_LITTLE_ENDIAN, BUS_BIG_ENDIAN))
+                return -EBADMSG;
+
+        /* Note that we are happy with unknown flags in the flags header! */
+
+        a = ALIGN(sizeof(sd_bus_message));
+
+        if (label) {
+                label_sz = strlen(label);
+                a += label_sz + 1;
+        }
+
+        m = malloc0(a);
+        if (!m)
+                return -ENOMEM;
+
+        m->sealed = true;
+        m->header = buffer;
+
+        if (h->serial == 0)
+                return -EBADMSG;
+
+        m->fields_size = BUS_MESSAGE_BSWAP32(m, h->fields_size);
+        m->body_size = BUS_MESSAGE_BSWAP32(m, h->body_size);
+
+        assert(message_size >= sizeof(struct bus_header));
+        if (ALIGN8(m->fields_size) > message_size - sizeof(struct bus_header) ||
+            m->body_size != message_size - sizeof(struct bus_header) - ALIGN8(m->fields_size))
+                return -EBADMSG;
+
+        m->fds = fds;
+        m->n_fds = n_fds;
+
+        if (label) {
+                m->creds.label = (char*) m + ALIGN(sizeof(sd_bus_message));
+                memcpy(m->creds.label, label, label_sz + 1);
+
+                m->creds.mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+        }
+
+        m->n_ref = 1;
+        m->bus = sd_bus_ref(bus);
+
+        *ret = TAKE_PTR(m);
+
+        return 0;
+}
+
+int bus_message_from_malloc(
+                sd_bus *bus,
+                void *buffer,
+                size_t length,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                sd_bus_message **ret) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        size_t sz;
+        int r;
+
+        r = message_from_header(
+                        bus,
+                        buffer, length,
+                        fds, n_fds,
+                        label,
+                        &m);
+        if (r < 0)
+                return r;
+
+        sz = length - sizeof(struct bus_header) - ALIGN8(m->fields_size);
+        if (sz > 0) {
+                m->n_body_parts = 1;
+                m->body.data = (uint8_t*) buffer + sizeof(struct bus_header) + ALIGN8(m->fields_size);
+                m->body.size = sz;
+                m->body.sealed = true;
+                m->body.memfd = -1;
+        }
+
+        m->n_iovec = 1;
+        m->iovec = m->iovec_fixed;
+        m->iovec[0] = IOVEC_MAKE(buffer, length);
+
+        r = message_parse_fields(m);
+        if (r < 0)
+                return r;
+
+        /* We take possession of the memory and fds now */
+        m->free_header = true;
+        m->free_fds = true;
+
+        *ret = TAKE_PTR(m);
+        return 0;
+}
+
+_public_ int sd_bus_message_new(
+                sd_bus *bus,
+                sd_bus_message **m,
+                uint8_t type) {
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(m, -EINVAL);
+        /* Creation of messages with _SD_BUS_MESSAGE_TYPE_INVALID is allowed. */
+        assert_return(type < _SD_BUS_MESSAGE_TYPE_MAX, -EINVAL);
+
+        sd_bus_message *t = malloc0(ALIGN(sizeof(sd_bus_message)) + sizeof(struct bus_header));
+        if (!t)
+                return -ENOMEM;
+
+        t->n_ref = 1;
+        t->bus = sd_bus_ref(bus);
+        t->header = (struct bus_header*) ((uint8_t*) t + ALIGN(sizeof(struct sd_bus_message)));
+        t->header->endian = BUS_NATIVE_ENDIAN;
+        t->header->type = type;
+        t->header->version = bus->message_version;
+        t->allow_fds = bus->can_fds || !IN_SET(bus->state, BUS_HELLO, BUS_RUNNING);
+
+        if (bus->allow_interactive_authorization)
+                t->header->flags |= BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION;
+
+        *m = t;
+        return 0;
+}
+
+_public_ int sd_bus_message_new_signal(
+                sd_bus *bus,
+                sd_bus_message **m,
+                const char *path,
+                const char *interface,
+                const char *member) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(interface_name_is_valid(interface), -EINVAL);
+        assert_return(member_name_is_valid(member), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_SIGNAL);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                return r;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_call(
+                sd_bus *bus,
+                sd_bus_message **m,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(!destination || service_name_is_valid(destination), -EINVAL);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!interface || interface_name_is_valid(interface), -EINVAL);
+        assert_return(member_name_is_valid(member), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_METHOD_CALL);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                return r;
+
+        if (interface) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+                if (r < 0)
+                        return r;
+        }
+
+        if (destination) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+static int message_new_reply(
+                sd_bus_message *call,
+                uint8_t type,
+                sd_bus_message **m) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        uint64_t cookie;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(m, -EINVAL);
+
+        cookie = BUS_MESSAGE_COOKIE(call);
+        if (cookie == 0)
+                return -EOPNOTSUPP;
+
+        r = sd_bus_message_new(call->bus, &t, type);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+        t->reply_cookie = cookie;
+        r = message_append_reply_cookie(t, t->reply_cookie);
+        if (r < 0)
+                return r;
+
+        if (call->sender) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, call->sender, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        t->dont_send = !!(call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED);
+        t->enforced_reply_signature = call->enforced_reply_signature;
+
+        /* let's copy the sensitive flag over. Let's do that as a safety precaution to keep a transaction
+         * wholly sensitive if already the incoming message was sensitive. This is particularly useful when a
+         * vtable record sets the SD_BUS_VTABLE_SENSITIVE flag on a method call, since this means it applies
+         * to both the message call and the reply. */
+        t->sensitive = call->sensitive;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_return(
+                sd_bus_message *call,
+                sd_bus_message **m) {
+
+        return message_new_reply(call, SD_BUS_MESSAGE_METHOD_RETURN, m);
+}
+
+_public_ int sd_bus_message_new_method_error(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                const sd_bus_error *e) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(sd_bus_error_is_set(e), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = message_new_reply(call, SD_BUS_MESSAGE_METHOD_ERROR, &t);
+        if (r < 0)
+                return r;
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, e->name, &t->error.name);
+        if (r < 0)
+                return r;
+
+        if (e->message) {
+                r = message_append_basic(t, SD_BUS_TYPE_STRING, e->message, (const void**) &t->error.message);
+                if (r < 0)
+                        return r;
+        }
+
+        t->error._need_free = -1;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_errorf(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                const char *name,
+                const char *format,
+                ...) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        va_list ap;
+
+        assert_return(name, -EINVAL);
+        assert_return(m, -EINVAL);
+
+        va_start(ap, format);
+        sd_bus_error_setfv(&error, name, format, ap);
+        va_end(ap);
+
+        return sd_bus_message_new_method_error(call, m, &error);
+}
+
+_public_ int sd_bus_message_new_method_errno(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                int error,
+                const sd_bus_error *p) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+
+        if (sd_bus_error_is_set(p))
+                return sd_bus_message_new_method_error(call, m, p);
+
+        sd_bus_error_set_errno(&berror, error);
+
+        return sd_bus_message_new_method_error(call, m, &berror);
+}
+
+_public_ int sd_bus_message_new_method_errnof(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                int error,
+                const char *format,
+                ...) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+        va_list ap;
+
+        va_start(ap, format);
+        sd_bus_error_set_errnofv(&berror, error, format, ap);
+        va_end(ap);
+
+        return sd_bus_message_new_method_error(call, m, &berror);
+}
+
+void bus_message_set_sender_local(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus.Local";
+        m->creds.well_known_names_local = true;
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+}
+
+void bus_message_set_sender_driver(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus";
+        m->creds.well_known_names_driver = true;
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+}
+
+int bus_message_new_synthetic_error(
+                sd_bus *bus,
+                uint64_t cookie,
+                const sd_bus_error *e,
+                sd_bus_message **m) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert(bus);
+        assert(sd_bus_error_is_set(e));
+        assert(m);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_METHOD_ERROR);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+        t->reply_cookie = cookie;
+
+        r = message_append_reply_cookie(t, t->reply_cookie);
+        if (r < 0)
+                return r;
+
+        if (bus && bus->unique_name) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, bus->unique_name, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, e->name, &t->error.name);
+        if (r < 0)
+                return r;
+
+        if (e->message) {
+                r = message_append_basic(t, SD_BUS_TYPE_STRING, e->message, (const void**) &t->error.message);
+                if (r < 0)
+                        return r;
+        }
+
+        t->error._need_free = -1;
+
+        bus_message_set_sender_driver(bus, t);
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ sd_bus_message* sd_bus_message_ref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        /* We are fine if this message so far was either explicitly reffed or not reffed but queued into at
+         * least one bus connection object. */
+        assert(m->n_ref > 0 || m->n_queued > 0);
+
+        m->n_ref++;
+
+        /* Each user reference to a bus message shall also be considered a ref on the bus */
+        sd_bus_ref(m->bus);
+        return m;
+}
+
+_public_ sd_bus_message* sd_bus_message_unref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        assert(m->n_ref > 0);
+
+        sd_bus_unref(m->bus); /* Each regular ref is also a ref on the bus connection. Let's hence drop it
+                               * here. Note we have to do this before decrementing our own n_ref here, since
+                               * otherwise, if this message is currently queued sd_bus_unref() might call
+                               * bus_message_unref_queued() for this which might then destroy the message
+                               * while we are still processing it. */
+        m->n_ref--;
+
+        if (m->n_ref > 0 || m->n_queued > 0)
+                return NULL;
+
+        /* Unset the bus field if neither the user has a reference nor this message is queued. We are careful
+         * to reset the field only after the last reference to the bus is dropped, after all we might keep
+         * multiple references to the bus, once for each reference kept on ourselves. */
+        m->bus = NULL;
+
+        return message_free(m);
+}
+
+sd_bus_message* bus_message_ref_queued(sd_bus_message *m, sd_bus *bus) {
+        if (!m)
+                return NULL;
+
+        /* If this is a different bus than the message is associated with, then implicitly turn this into a
+         * regular reference. This means that you can create a memory leak by enqueuing a message generated
+         * on one bus onto another at the same time as enqueueing a message from the second one on the first,
+         * as we'll not detect the cyclic references there. */
+        if (bus != m->bus)
+                return sd_bus_message_ref(m);
+
+        assert(m->n_ref > 0 || m->n_queued > 0);
+        m->n_queued++;
+
+        return m;
+}
+
+sd_bus_message* bus_message_unref_queued(sd_bus_message *m, sd_bus *bus) {
+        if (!m)
+                return NULL;
+
+        if (bus != m->bus)
+                return sd_bus_message_unref(m);
+
+        assert(m->n_queued > 0);
+        m->n_queued--;
+
+        if (m->n_ref > 0 || m->n_queued > 0)
+                return NULL;
+
+        m->bus = NULL;
+
+        return message_free(m);
+}
+
+_public_ int sd_bus_message_get_type(sd_bus_message *m, uint8_t *type) {
+        assert_return(m, -EINVAL);
+        assert_return(type, -EINVAL);
+
+        *type = m->header->type;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_cookie(sd_bus_message *m, uint64_t *cookie) {
+        uint64_t c;
+
+        assert_return(m, -EINVAL);
+        assert_return(cookie, -EINVAL);
+
+        c = BUS_MESSAGE_COOKIE(m);
+        if (c == 0)
+                return -ENODATA;
+
+        *cookie = BUS_MESSAGE_COOKIE(m);
+        return 0;
+}
+
+_public_ int sd_bus_message_get_reply_cookie(sd_bus_message *m, uint64_t *cookie) {
+        assert_return(m, -EINVAL);
+        assert_return(cookie, -EINVAL);
+
+        if (m->reply_cookie == 0)
+                return -ENODATA;
+
+        *cookie = m->reply_cookie;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_expect_reply(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return m->header->type == SD_BUS_MESSAGE_METHOD_CALL &&
+                !(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED);
+}
+
+_public_ int sd_bus_message_get_auto_start(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return !(m->header->flags & BUS_MESSAGE_NO_AUTO_START);
+}
+
+_public_ int sd_bus_message_get_allow_interactive_authorization(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return m->header->type == SD_BUS_MESSAGE_METHOD_CALL &&
+                (m->header->flags & BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION);
+}
+
+_public_ const char *sd_bus_message_get_path(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->path;
+}
+
+_public_ const char *sd_bus_message_get_interface(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->interface;
+}
+
+_public_ const char *sd_bus_message_get_member(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->member;
+}
+
+_public_ const char *sd_bus_message_get_destination(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->destination;
+}
+
+_public_ const char *sd_bus_message_get_sender(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->sender;
+}
+
+_public_ const sd_bus_error *sd_bus_message_get_error(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        if (!sd_bus_error_is_set(&m->error))
+                return NULL;
+
+        return &m->error;
+}
+
+_public_ int sd_bus_message_get_monotonic_usec(sd_bus_message *m, uint64_t *usec) {
+        assert_return(m, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        if (m->monotonic <= 0)
+                return -ENODATA;
+
+        *usec = m->monotonic;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_realtime_usec(sd_bus_message *m, uint64_t *usec) {
+        assert_return(m, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        if (m->realtime <= 0)
+                return -ENODATA;
+
+        *usec = m->realtime;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_seqnum(sd_bus_message *m, uint64_t *seqnum) {
+        assert_return(m, -EINVAL);
+        assert_return(seqnum, -EINVAL);
+
+        if (m->seqnum <= 0)
+                return -ENODATA;
+
+        *seqnum = m->seqnum;
+        return 0;
+}
+
+_public_ sd_bus_creds *sd_bus_message_get_creds(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        if (m->creds.mask == 0)
+                return NULL;
+
+        return &m->creds;
+}
+
+_public_ int sd_bus_message_is_signal(
+                sd_bus_message *m,
+                const char *interface,
+                const char *member) {
+
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_SIGNAL)
+                return 0;
+
+        if (interface && !streq_ptr(m->interface, interface))
+                return 0;
+
+        if (member && !streq_ptr(m->member, member))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_is_method_call(
+                sd_bus_message *m,
+                const char *interface,
+                const char *member) {
+
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 0;
+
+        if (interface && !streq_ptr(m->interface, interface))
+                return 0;
+
+        if (member && !streq_ptr(m->member, member))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_is_method_error(sd_bus_message *m, const char *name) {
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
+                return 0;
+
+        if (name && !streq_ptr(m->error.name, name))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_set_expect_reply(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_NO_REPLY_EXPECTED, !b);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_auto_start(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_NO_AUTO_START, !b);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_allow_interactive_authorization(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION, b);
+
+        return 0;
+}
+
+static struct bus_body_part *message_append_part(sd_bus_message *m) {
+        struct bus_body_part *part;
+
+        assert(m);
+
+        if (m->poisoned)
+                return NULL;
+
+        if (m->n_body_parts <= 0) {
+                part = &m->body;
+                zero(*part);
+        } else {
+                assert(m->body_end);
+
+                part = new0(struct bus_body_part, 1);
+                if (!part) {
+                        m->poisoned = true;
+                        return NULL;
+                }
+
+                m->body_end->next = part;
+        }
+
+        part->memfd = -1;
+        m->body_end = part;
+        m->n_body_parts++;
+
+        return part;
+}
+
+static void part_zero(struct bus_body_part *part, size_t sz) {
+        assert(part);
+        assert(sz > 0);
+        assert(sz < 8);
+
+        /* All other fields can be left in their defaults */
+        assert(!part->data);
+        assert(part->memfd < 0);
+
+        part->size = sz;
+        part->is_zero = true;
+        part->sealed = true;
+}
+
+static int part_make_space(
+                struct sd_bus_message *m,
+                struct bus_body_part *part,
+                size_t sz,
+                void **q) {
+
+        void *n;
+
+        assert(m);
+        assert(part);
+        assert(!part->sealed);
+
+        if (m->poisoned)
+                return -ENOMEM;
+
+        if (part->allocated == 0 || sz > part->allocated) {
+                size_t new_allocated;
+
+                new_allocated = sz > 0 ? 2 * sz : 64;
+                n = realloc(part->data, new_allocated);
+                if (!n) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                part->data = n;
+                part->allocated = new_allocated;
+                part->free_this = true;
+        }
+
+        if (q)
+                *q = part->data ? (uint8_t*) part->data + part->size : NULL;
+
+        part->size = sz;
+        return 0;
+}
+
+static void message_extend_containers(sd_bus_message *m, size_t expand) {
+        assert(m);
+
+        if (expand <= 0)
+                return;
+
+        if (m->n_containers <= 0)
+                return;
+
+        /* Update counters */
+        for (struct bus_container *c = m->containers; c < m->containers + m->n_containers; c++)
+                if (c->array_size)
+                        *c->array_size += expand;
+}
+
+static void *message_extend_body(
+                sd_bus_message *m,
+                size_t align,
+                size_t sz) {
+
+        size_t start_body, end_body, padding, added;
+        void *p;
+        int r;
+
+        assert(m);
+        assert(align > 0);
+        assert(!m->sealed);
+
+        if (m->poisoned)
+                return NULL;
+
+        start_body = ALIGN_TO(m->body_size, align);
+        end_body = start_body + sz;
+
+        padding = start_body - m->body_size;
+        added = padding + sz;
+
+        /* Check for 32bit overflows */
+        if (end_body < start_body || end_body > UINT32_MAX) {
+                m->poisoned = true;
+                return NULL;
+        }
+
+        if (added > 0) {
+                struct bus_body_part *part = NULL;
+                bool add_new_part;
+
+                add_new_part =
+                        m->n_body_parts <= 0 ||
+                        m->body_end->sealed ||
+                        (padding != ALIGN_TO(m->body_end->size, align) - m->body_end->size);
+                        /* If this must be an inlined extension, let's create a new part if
+                         * the previous part is large enough to be inlined. */
+
+                if (add_new_part) {
+                        if (padding > 0) {
+                                part = message_append_part(m);
+                                if (!part)
+                                        return NULL;
+
+                                part_zero(part, padding);
+                        }
+
+                        part = message_append_part(m);
+                        if (!part)
+                                return NULL;
+
+                        r = part_make_space(m, part, sz, &p);
+                        if (r < 0)
+                                return NULL;
+                } else {
+                        void *op;
+                        size_t os, start_part, end_part;
+
+                        part = m->body_end;
+                        op = part->data;
+                        os = part->size;
+
+                        start_part = ALIGN_TO(part->size, align);
+                        end_part = start_part + sz;
+
+                        r = part_make_space(m, part, end_part, &p);
+                        if (r < 0)
+                                return NULL;
+
+                        if (padding > 0) {
+                                memzero(p, padding);
+                                p = (uint8_t*) p + padding;
+                        }
+
+                        /* Readjust pointers */
+                        if (m->n_containers > 0)
+                                for (struct bus_container *c = m->containers; c < m->containers + m->n_containers; c++)
+                                        c->array_size = adjust_pointer(c->array_size, op, os, part->data);
+
+                        m->error.message = (const char*) adjust_pointer(m->error.message, op, os, part->data);
+                }
+        } else
+                /* Return something that is not NULL and is aligned */
+                p = (uint8_t*) align;
+
+        m->body_size = end_body;
+        message_extend_containers(m, added);
+
+        return p;
+}
+
+static int message_push_fd(sd_bus_message *m, int fd) {
+        int *f, copy;
+
+        assert(m);
+
+        if (fd < 0)
+                return -EINVAL;
+
+        if (!m->allow_fds)
+                return -EOPNOTSUPP;
+
+        copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+        if (copy < 0)
+                return -errno;
+
+        f = reallocarray(m->fds, m->n_fds + 1, sizeof(int));
+        if (!f) {
+                m->poisoned = true;
+                safe_close(copy);
+                return -ENOMEM;
+        }
+
+        m->fds = f;
+        m->fds[m->n_fds] = copy;
+        m->free_fds = true;
+
+        return copy;
+}
+
+int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored) {
+        _cleanup_close_ int fd = -1;
+        struct bus_container *c;
+        ssize_t align, sz;
+        uint32_t u32;
+        void *a;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_basic(type), -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != type)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(type));
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        switch (type) {
+
+        case SD_BUS_TYPE_STRING:
+                /* To make things easy we'll serialize a NULL string
+                 * into the empty string */
+                p = strempty(p);
+
+                if (!utf8_is_valid(p))
+                        return -EINVAL;
+
+                align = 4;
+                sz = 4 + strlen(p) + 1;
+                break;
+
+        case SD_BUS_TYPE_OBJECT_PATH:
+
+                if (!p)
+                        return -EINVAL;
+
+                if (!object_path_is_valid(p))
+                        return -EINVAL;
+
+                align = 4;
+                sz = 4 + strlen(p) + 1;
+                break;
+
+        case SD_BUS_TYPE_SIGNATURE:
+
+                p = strempty(p);
+
+                if (!signature_is_valid(p, /* allow_dict_entry = */ true))
+                        return -EINVAL;
+
+                align = 1;
+                sz = 1 + strlen(p) + 1;
+                break;
+
+        case SD_BUS_TYPE_BOOLEAN:
+
+                u32 = p && *(int*) p;
+                p = &u32;
+
+                align = sz = 4;
+                break;
+
+        case SD_BUS_TYPE_UNIX_FD:
+
+                if (!p)
+                        return -EINVAL;
+
+                fd = message_push_fd(m, *(int*) p);
+                if (fd < 0)
+                        return fd;
+
+                u32 = m->n_fds;
+                p = &u32;
+
+                align = sz = 4;
+                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)
+                return -ENOMEM;
+
+        if (IN_SET(type, SD_BUS_TYPE_STRING, 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 - 2;
+                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 (type == SD_BUS_TYPE_UNIX_FD)
+                m->n_fds++;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        fd = -1;
+        return 0;
+}
+
+_public_ int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p) {
+        return message_append_basic(m, type, p, NULL);
+}
+
+_public_ int sd_bus_message_append_string_space(
+                sd_bus_message *m,
+                size_t size,
+                char **s) {
+
+        struct bus_container *c;
+        void *a;
+
+        assert_return(m, -EINVAL);
+        assert_return(s, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRING)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRING));
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        a = message_extend_body(m, 4, 4 + size + 1);
+        if (!a)
+                return -ENOMEM;
+
+        *(uint32_t*) a = size;
+        *s = (char*) a + 4;
+
+        (*s)[size] = 0;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_string_iovec(
+                sd_bus_message *m,
+                const struct iovec *iov,
+                unsigned n /* should be size_t, but is API now… 😞 */) {
+
+        size_t size;
+        unsigned i;
+        char *p;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(iov || n == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        size = IOVEC_TOTAL_SIZE(iov, n);
+
+        r = sd_bus_message_append_string_space(m, size, &p);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < n; i++) {
+
+                if (iov[i].iov_base)
+                        memcpy(p, iov[i].iov_base, iov[i].iov_len);
+                else
+                        memset(p, ' ', iov[i].iov_len);
+
+                p += iov[i].iov_len;
+        }
+
+        return 0;
+}
+
+static int bus_message_open_array(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                uint32_t **array_size,
+                size_t *begin) {
+
+        unsigned nindex;
+        int alignment;
+        void *a, *op;
+        size_t os;
+        struct bus_body_part *o;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(array_size);
+        assert(begin);
+
+        if (!signature_is_single(contents, true))
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+
+                /* Verify the existing signature */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_ARRAY)
+                        return -ENXIO;
+
+                if (!startswith(c->signature + c->index + 1, contents))
+                        return -ENXIO;
+
+                nindex = c->index + 1 + strlen(contents);
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                /* Extend the existing signature */
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_ARRAY), contents);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                nindex = e - c->signature;
+        }
+
+        alignment = bus_type_get_alignment(contents[0]);
+        if (alignment < 0)
+                return alignment;
+
+        a = message_extend_body(m, 4, 4);
+        if (!a)
+                return -ENOMEM;
+
+        o = m->body_end;
+        op = m->body_end->data;
+        os = m->body_end->size;
+
+        /* Add alignment between size and first element */
+        if (!message_extend_body(m, alignment, 0))
+                return -ENOMEM;
+
+        /* location of array size might have changed so let's readjust a */
+        if (o == m->body_end)
+                a = adjust_pointer(a, op, os, m->body_end->data);
+
+        *(uint32_t*) a = 0;
+        *array_size = a;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+static int bus_message_open_variant(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t l;
+        void *a;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_single(contents, false))
+                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 -ENXIO;
+
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_VARIANT));
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        l = strlen(contents);
+        a = message_extend_body(m, 1, 1 + l + 1);
+        if (!a)
+                return -ENOMEM;
+
+        *(uint8_t*) a = l;
+        memcpy((uint8_t*) a + 1, contents, l + 1);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+static int bus_message_open_struct(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *begin) {
+
+        size_t nindex;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(begin);
+
+        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 -ENXIO;
+
+                nindex = c->index + 1 + l + 1;
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_BEGIN), contents, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_END));
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                nindex = e - c->signature;
+        }
+
+        /* 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;
+}
+
+static int bus_message_open_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *begin) {
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(begin);
+
+        if (!signature_is_pair(contents))
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        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 -ENXIO;
+        } else
+                return -ENXIO;
+
+        /* Align contents to 8 byte boundary */
+        if (!message_extend_body(m, 8, 0))
+                return -ENOMEM;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_open_container(
+                sd_bus_message *m,
+                char type,
+                const char *contents) {
+
+        struct bus_container *c;
+        uint32_t *array_size = NULL;
+        _cleanup_free_ char *signature = NULL;
+        size_t before, begin = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(contents, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        /* Make sure we have space for one more container */
+        if (!GREEDY_REALLOC(m->containers, m->n_containers + 1)) {
+                m->poisoned = true;
+                return -ENOMEM;
+        }
+
+        c = message_get_last_container(m);
+
+        signature = strdup(contents);
+        if (!signature) {
+                m->poisoned = true;
+                return -ENOMEM;
+        }
+
+        /* Save old index in the parent container, in case we have to
+         * abort this container */
+        c->saved_index = c->index;
+        before = m->body_size;
+
+        if (type == SD_BUS_TYPE_ARRAY)
+                r = bus_message_open_array(m, c, contents, &array_size, &begin);
+        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, &begin);
+        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                r = bus_message_open_dict_entry(m, c, contents, &begin);
+        else
+                r = -EINVAL;
+        if (r < 0)
+                return r;
+
+        /* OK, let's fill it in */
+        m->containers[m->n_containers++] = (struct bus_container) {
+                .enclosing = type,
+                .signature = TAKE_PTR(signature),
+                .array_size = array_size,
+                .before = before,
+                .begin = begin,
+        };
+
+        return 0;
+}
+
+_public_ int sd_bus_message_close_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers > 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                if (c->signature && c->signature[c->index] != 0)
+                        return -EINVAL;
+
+        m->n_containers--;
+
+        free(c->signature);
+
+        return 0;
+}
+
+typedef struct {
+        const char *types;
+        unsigned n_struct;
+        unsigned n_array;
+} TypeStack;
+
+static int type_stack_push(TypeStack *stack, unsigned max, unsigned *i, const char *types, unsigned n_struct, unsigned n_array) {
+        assert(stack);
+        assert(max > 0);
+
+        if (*i >= max)
+                return -EINVAL;
+
+        stack[*i].types = types;
+        stack[*i].n_struct = n_struct;
+        stack[*i].n_array = n_array;
+        (*i)++;
+
+        return 0;
+}
+
+static int type_stack_pop(TypeStack *stack, unsigned max, unsigned *i, const char **types, unsigned *n_struct, unsigned *n_array) {
+        assert(stack);
+        assert(max > 0);
+        assert(types);
+        assert(n_struct);
+        assert(n_array);
+
+        if (*i <= 0)
+                return 0;
+
+        (*i)--;
+        *types = stack[*i].types;
+        *n_struct = stack[*i].n_struct;
+        *n_array = stack[*i].n_array;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_appendv(
+                sd_bus_message *m,
+                const char *types,
+                va_list ap) {
+
+        unsigned n_array, n_struct;
+        TypeStack stack[BUS_CONTAINER_DEPTH];
+        unsigned stack_ptr = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(types, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        n_array = UINT_MAX;
+        n_struct = strlen(types);
+
+        for (;;) {
+                const char *t;
+
+                if (n_array == 0 || (n_array == UINT_MAX && n_struct == 0)) {
+                        r = type_stack_pop(stack, ELEMENTSOF(stack), &stack_ptr, &types, &n_struct, &n_array);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = sd_bus_message_close_container(m);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                t = types;
+                if (n_array != UINT_MAX)
+                        n_array--;
+                else {
+                        types++;
+                        n_struct--;
+                }
+
+                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:
+                case SD_BUS_TYPE_UNIX_FD: {
+                        uint32_t x;
+
+                        /* We assume a boolean is the same as int32_t */
+                        assert_cc(sizeof(int32_t) == sizeof(int));
+
+                        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: {
+                        uint64_t x;
+
+                        x = va_arg(ap, uint64_t);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_DOUBLE: {
+                        double x;
+
+                        x = va_arg(ap, double);
+                        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_ARRAY: {
+                        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;
+
+                                r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (n_array == UINT_MAX) {
+                                types += k;
+                                n_struct -= k;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k;
+                        n_array = va_arg(ap, unsigned);
+
+                        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 = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = s;
+                        n_struct = strlen(s);
+                        n_array = UINT_MAX;
+
+                        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;
+                        if (k < 2)
+                                return -ERANGE;
+
+                        {
+                                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;
+                        }
+
+                        if (n_array == UINT_MAX) {
+                                types += k - 1;
+                                n_struct -= k - 1;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k - 2;
+                        n_array = UINT_MAX;
+
+                        break;
+                }
+
+                default:
+                        r = -EINVAL;
+                }
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+}
+
+_public_ int sd_bus_message_append(sd_bus_message *m, const char *types, ...) {
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_message_appendv(m, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_message_append_array_space(
+                sd_bus_message *m,
+                char type,
+                size_t size,
+                void **ptr) {
+
+        ssize_t align, sz;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type) && type != SD_BUS_TYPE_BOOLEAN, -EINVAL);
+        assert_return(ptr || size == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        align = bus_type_get_alignment(type);
+        sz = bus_type_get_size(type);
+
+        assert_se(align > 0);
+        assert_se(sz > 0);
+
+        if (size % sz != 0)
+                return -EINVAL;
+
+        r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+
+        a = message_extend_body(m, align, size);
+        if (!a)
+                return -ENOMEM;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        *ptr = a;
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array(
+                sd_bus_message *m,
+                char type,
+                const void *ptr,
+                size_t size) {
+        int r;
+        void *p;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(ptr || size == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = sd_bus_message_append_array_space(m, type, size, &p);
+        if (r < 0)
+                return r;
+
+        memcpy_safe(p, ptr, size);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array_iovec(
+                sd_bus_message *m,
+                char type,
+                const struct iovec *iov,
+                unsigned n /* should be size_t, but is API now… 😞 */) {
+
+        size_t size;
+        unsigned i;
+        void *p;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(iov || n == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        size = IOVEC_TOTAL_SIZE(iov, n);
+
+        r = sd_bus_message_append_array_space(m, type, size, &p);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < n; i++) {
+
+                if (iov[i].iov_base)
+                        memcpy(p, iov[i].iov_base, iov[i].iov_len);
+                else
+                        memzero(p, iov[i].iov_len);
+
+                p = (uint8_t*) p + iov[i].iov_len;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array_memfd(
+                sd_bus_message *m,
+                char type,
+                int memfd,
+                uint64_t offset,
+                uint64_t size) {
+
+        _cleanup_close_ int copy_fd = -1;
+        struct bus_body_part *part;
+        ssize_t align, sz;
+        uint64_t real_size;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(memfd >= 0, -EBADF);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(size > 0, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = memfd_set_sealed(memfd);
+        if (r < 0)
+                return r;
+
+        copy_fd = fcntl(memfd, F_DUPFD_CLOEXEC, 3);
+        if (copy_fd < 0)
+                return copy_fd;
+
+        r = memfd_get_size(memfd, &real_size);
+        if (r < 0)
+                return r;
+
+        if (offset == 0 && size == UINT64_MAX)
+                size = real_size;
+        else if (offset + size > real_size)
+                return -EMSGSIZE;
+
+        align = bus_type_get_alignment(type);
+        sz = bus_type_get_size(type);
+
+        assert_se(align > 0);
+        assert_se(sz > 0);
+
+        if (offset % align != 0)
+                return -EINVAL;
+
+        if (size % sz != 0)
+                return -EINVAL;
+
+        if (size > (uint64_t) UINT32_MAX)
+                return -EINVAL;
+
+        r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+
+        a = message_extend_body(m, align, 0);
+        if (!a)
+                return -ENOMEM;
+
+        part = message_append_part(m);
+        if (!part)
+                return -ENOMEM;
+
+        part->memfd = copy_fd;
+        part->memfd_offset = offset;
+        part->sealed = true;
+        part->size = size;
+        copy_fd = -1;
+
+        m->body_size += size;
+        message_extend_containers(m, size);
+
+        return sd_bus_message_close_container(m);
+}
+
+_public_ int sd_bus_message_append_string_memfd(
+                sd_bus_message *m,
+                int memfd,
+                uint64_t offset,
+                uint64_t size) {
+
+        _cleanup_close_ int copy_fd = -1;
+        struct bus_body_part *part;
+        struct bus_container *c;
+        uint64_t real_size;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(memfd >= 0, -EBADF);
+        assert_return(size > 0, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = memfd_set_sealed(memfd);
+        if (r < 0)
+                return r;
+
+        copy_fd = fcntl(memfd, FD_CLOEXEC, 3);
+        if (copy_fd < 0)
+                return copy_fd;
+
+        r = memfd_get_size(memfd, &real_size);
+        if (r < 0)
+                return r;
+
+        if (offset == 0 && size == UINT64_MAX)
+                size = real_size;
+        else if (offset + size > real_size)
+                return -EMSGSIZE;
+
+        /* We require this to be NUL terminated */
+        if (size == 0)
+                return -EINVAL;
+
+        if (size > (uint64_t) UINT32_MAX)
+                return -EINVAL;
+
+        c = message_get_last_container(m);
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRING)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRING));
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        a = message_extend_body(m, 4, 4);
+        if (!a)
+                return -ENOMEM;
+
+        *(uint32_t*) a = size - 1;
+
+        part = message_append_part(m);
+        if (!part)
+                return -ENOMEM;
+
+        part->memfd = copy_fd;
+        part->memfd_offset = offset;
+        part->sealed = true;
+        part->size = size;
+        copy_fd = -1;
+
+        m->body_size += size;
+        message_extend_containers(m, size);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_strv(sd_bus_message *m, char **l) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, l) {
+                r = sd_bus_message_append_basic(m, 's', *i);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_message_close_container(m);
+}
+
+static int bus_message_close_header(sd_bus_message *m) {
+        assert(m);
+
+        /* The actual user data is finished now, we just complete the variant and struct now. Remember
+         * this position, so that during parsing we know where to put the outer container end. */
+        m->user_body_size = m->body_size;
+
+        m->header->fields_size = m->fields_size;
+        m->header->body_size = m->body_size;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_seal(sd_bus_message *m, uint64_t cookie, uint64_t timeout_usec) {
+        struct bus_body_part *part;
+        size_t a;
+        unsigned i;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (m->sealed)
+                return -EPERM;
+
+        if (m->n_containers > 0)
+                return -EBADMSG;
+
+        if (m->poisoned)
+                return -ESTALE;
+
+        if (cookie > UINT32_MAX)
+                return -EOPNOTSUPP;
+
+        /* In vtables the return signature of method calls is listed,
+         * let's check if they match if this is a response */
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_RETURN &&
+            m->enforced_reply_signature &&
+            !streq(strempty(m->root_container.signature), m->enforced_reply_signature))
+                return -ENOMSG;
+
+        /* 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, BUS_MESSAGE_HEADER_SIGNATURE, m->root_container.signature, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        if (m->n_fds > 0) {
+                r = message_append_field_uint32(m, BUS_MESSAGE_HEADER_UNIX_FDS, m->n_fds);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_message_close_header(m);
+        if (r < 0)
+                return r;
+
+        m->header->serial = (uint32_t) cookie;
+
+        m->timeout = m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED ? 0 : timeout_usec;
+
+        /* Add padding at the end of the fields part, since we know
+         * the body needs to start at an 8 byte alignment. We made
+         * sure we allocated enough space for this, so all we need to
+         * do here is to zero it out. */
+        a = ALIGN8(m->fields_size) - m->fields_size;
+        if (a > 0)
+                memzero((uint8_t*) BUS_MESSAGE_FIELDS(m) + m->fields_size, a);
+
+        /* If this is something we can send as memfd, then let's seal
+        the memfd now. Note that we can send memfds as payload only
+        for directed messages, and not for broadcasts. */
+        if (m->destination && m->bus->use_memfd) {
+                MESSAGE_FOREACH_PART(part, i, m)
+                        if (part->memfd >= 0 &&
+                            !part->sealed &&
+                            (part->size > MEMFD_MIN_SIZE || m->bus->use_memfd < 0) &&
+                            part != m->body_end) { /* The last part may never be sent as memfd */
+                                uint64_t sz;
+
+                                /* Try to seal it if that makes
+                                 * sense. First, unmap our own map to
+                                 * make sure we don't keep it busy. */
+                                bus_body_part_unmap(part);
+
+                                /* Then, sync up real memfd size */
+                                sz = part->size;
+                                r = memfd_set_size(part->memfd, sz);
+                                if (r < 0)
+                                        return r;
+
+                                /* Finally, try to seal */
+                                if (memfd_set_sealed(part->memfd) >= 0)
+                                        part->sealed = true;
+                        }
+        }
+
+        m->root_container.end = m->user_body_size;
+        m->root_container.index = 0;
+
+        m->sealed = true;
+
+        return 0;
+}
+
+int bus_body_part_map(struct bus_body_part *part) {
+        void *p;
+        size_t psz, shift;
+
+        assert_se(part);
+
+        if (part->data)
+                return 0;
+
+        if (part->size <= 0)
+                return 0;
+
+        /* For smaller zero parts (as used for padding) we don't need to map anything... */
+        if (part->memfd < 0 && part->is_zero && part->size < 8) {
+                static const uint8_t zeroes[7] = { };
+                part->data = (void*) zeroes;
+                return 0;
+        }
+
+        shift = PAGE_OFFSET(part->memfd_offset);
+        psz = PAGE_ALIGN(part->size + shift);
+
+        if (part->memfd >= 0)
+                p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE, part->memfd, part->memfd_offset - shift);
+        else if (part->is_zero)
+                p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+        else
+                return -EINVAL;
+
+        if (p == MAP_FAILED)
+                return -errno;
+
+        part->mapped = psz;
+        part->mmap_begin = p;
+        part->data = (uint8_t*) p + shift;
+        part->munmap_this = true;
+
+        return 0;
+}
+
+void bus_body_part_unmap(struct bus_body_part *part) {
+
+        assert_se(part);
+
+        if (part->memfd < 0)
+                return;
+
+        if (!part->mmap_begin)
+                return;
+
+        if (!part->munmap_this)
+                return;
+
+        assert_se(munmap(part->mmap_begin, part->mapped) == 0);
+
+        part->mmap_begin = NULL;
+        part->data = NULL;
+        part->mapped = 0;
+        part->munmap_this = false;
+
+        return;
+}
+
+static bool message_end_of_signature(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert(m);
+
+        c = message_get_last_container(m);
+        return !c->signature || c->signature[c->index] == 0;
+}
+
+static bool message_end_of_array(sd_bus_message *m, size_t index) {
+        struct bus_container *c;
+
+        assert(m);
+
+        c = message_get_last_container(m);
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return false;
+
+        assert(c->array_size);
+        return index >= c->begin + BUS_MESSAGE_BSWAP32(m, *c->array_size);
+}
+
+_public_ int sd_bus_message_at_end(sd_bus_message *m, int complete) {
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (complete && m->n_containers > 0)
+                return false;
+
+        if (message_end_of_signature(m))
+                return true;
+
+        if (message_end_of_array(m, m->rindex))
+                return true;
+
+        return false;
+}
+
+static struct bus_body_part* find_part(sd_bus_message *m, size_t index, size_t sz, void **p) {
+        struct bus_body_part *part;
+        size_t begin;
+        int r;
+
+        assert(m);
+
+        if (m->cached_rindex_part && index >= m->cached_rindex_part_begin) {
+                part = m->cached_rindex_part;
+                begin = m->cached_rindex_part_begin;
+        } else {
+                part = &m->body;
+                begin = 0;
+        }
+
+        while (part) {
+                if (index < begin)
+                        return NULL;
+
+                if (index + sz <= begin + part->size) {
+
+                        r = bus_body_part_map(part);
+                        if (r < 0)
+                                return NULL;
+
+                        if (p)
+                                *p = part->data ? (uint8_t*) part->data + index - begin
+                                        : NULL; /* Avoid dereferencing a NULL pointer. */
+
+                        m->cached_rindex_part = part;
+                        m->cached_rindex_part_begin = begin;
+
+                        return part;
+                }
+
+                begin += part->size;
+                part = part->next;
+        }
+
+        return NULL;
+}
+
+static int message_peek_body(
+                sd_bus_message *m,
+                size_t *rindex,
+                size_t align,
+                size_t nbytes,
+                void **ret) {
+
+        size_t k, start, end, padding;
+        struct bus_body_part *part;
+        uint8_t *q;
+
+        assert(m);
+        assert(rindex);
+        assert(align > 0);
+
+        start = ALIGN_TO(*rindex, align);
+        if (start > m->user_body_size)
+                return -EBADMSG;
+
+        padding = start - *rindex;
+
+        /* Avoid overflow below */
+        if (nbytes > SIZE_MAX - start)
+                return -EBADMSG;
+
+        end = start + nbytes;
+        if (end > m->user_body_size)
+                return -EBADMSG;
+
+        part = find_part(m, *rindex, padding, (void**) &q);
+        if (!part)
+                return -EBADMSG;
+
+        if (q) {
+                /* Verify padding */
+                for (k = 0; k < padding; k++)
+                        if (q[k] != 0)
+                                return -EBADMSG;
+        }
+
+        part = find_part(m, start, nbytes, (void**) &q);
+        if (!part || (nbytes > 0 && !q))
+                return -EBADMSG;
+
+        *rindex = end;
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static bool validate_nul(const char *s, size_t l) {
+
+        /* Check for NUL chars in the string */
+        if (memchr(s, 0, l))
+                return false;
+
+        /* Check for NUL termination */
+        if (s[l] != 0)
+                return false;
+
+        return true;
+}
+
+static bool validate_string(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        /* Check if valid UTF8 */
+        if (!utf8_is_valid(s))
+                return false;
+
+        return true;
+}
+
+static bool validate_signature(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        /* Check if valid signature */
+        if (!signature_is_valid(s, true))
+                return false;
+
+        return true;
+}
+
+static bool validate_object_path(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        if (!object_path_is_valid(s))
+                return false;
+
+        return true;
+}
+
+_public_ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
+        struct bus_container *c;
+        size_t rindex;
+        void *q;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(bus_type_is_basic(type), -EINVAL);
+
+        if (message_end_of_signature(m))
+                return -ENXIO;
+
+        if (message_end_of_array(m, m->rindex))
+                return 0;
+
+        c = message_get_last_container(m);
+        if (c->signature[c->index] != type)
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        if (IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH)) {
+                uint32_t l;
+                bool ok;
+
+                r = message_peek_body(m, &rindex, 4, 4, &q);
+                if (r < 0)
+                        return r;
+
+                l = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                if (l == UINT32_MAX)
+                        /* avoid overflow right below */
+                        return -EBADMSG;
+
+                r = message_peek_body(m, &rindex, 1, l+1, &q);
+                if (r < 0)
+                        return r;
+
+                if (type == SD_BUS_TYPE_OBJECT_PATH)
+                        ok = validate_object_path(q, l);
+                else
+                        ok = validate_string(q, l);
+                if (!ok)
+                        return -EBADMSG;
+
+                if (p)
+                        *(const char**) p = q;
+
+        } else if (type == SD_BUS_TYPE_SIGNATURE) {
+                uint8_t l;
+
+                r = message_peek_body(m, &rindex, 1, 1, &q);
+                if (r < 0)
+                        return r;
+
+                l = *(uint8_t*) q;
+                if (l == UINT8_MAX)
+                        /* avoid overflow right below */
+                        return -EBADMSG;
+
+                r = message_peek_body(m, &rindex, 1, l+1, &q);
+                if (r < 0)
+                        return r;
+
+                if (!validate_signature(q, l))
+                        return -EBADMSG;
+
+                if (p)
+                        *(const char**) p = q;
+
+        } else {
+                ssize_t sz, align;
+
+                align = bus_type_get_alignment(type);
+                assert(align > 0);
+
+                sz = bus_type_get_size(type);
+                assert(sz > 0);
+
+                r = message_peek_body(m, &rindex, align, sz, &q);
+                if (r < 0)
+                        return r;
+
+                switch (type) {
+
+                case SD_BUS_TYPE_BYTE:
+                        if (p)
+                                *(uint8_t*) p = *(uint8_t*) q;
+                        break;
+
+                case SD_BUS_TYPE_BOOLEAN:
+                        if (p)
+                                *(int*) p = !!*(uint32_t*) q;
+                        break;
+
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                        if (p)
+                                *(uint16_t*) p = BUS_MESSAGE_BSWAP16(m, *(uint16_t*) q);
+                        break;
+
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                        if (p)
+                                *(uint32_t*) p = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                        break;
+
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                        if (p)
+                                *(uint64_t*) p = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
+                        break;
+
+                case SD_BUS_TYPE_UNIX_FD: {
+                        uint32_t j;
+
+                        j = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                        if (j >= m->n_fds)
+                                return -EBADMSG;
+
+                        if (p)
+                                *(int*) p = m->fds[j];
+                        break;
+                }
+
+                default:
+                        assert_not_reached();
+                }
+        }
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 1;
+}
+
+static int bus_message_enter_array(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                uint32_t **array_size) {
+
+        size_t rindex;
+        void *q;
+        int alignment, r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(array_size);
+
+        if (!signature_is_single(contents, true))
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        if (c->signature[c->index] != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        if (!startswith(c->signature + c->index + 1, contents))
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        r = message_peek_body(m, &rindex, 4, 4, &q);
+        if (r < 0)
+                return r;
+
+        if (BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q) > BUS_ARRAY_MAX_SIZE)
+                return -EBADMSG;
+
+        alignment = bus_type_get_alignment(contents[0]);
+        if (alignment < 0)
+                return alignment;
+
+        r = message_peek_body(m, &rindex, alignment, 0, NULL);
+        if (r < 0)
+                return r;
+
+        *array_size = (uint32_t*) q;
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + strlen(contents);
+
+        return 1;
+}
+
+static int bus_message_enter_variant(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t rindex;
+        uint8_t l;
+        void *q;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_single(contents, false))
+                return -EINVAL;
+
+        if (*contents == SD_BUS_TYPE_DICT_ENTRY_BEGIN)
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        if (c->signature[c->index] != SD_BUS_TYPE_VARIANT)
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        r = message_peek_body(m, &rindex, 1, 1, &q);
+        if (r < 0)
+                return r;
+
+        l = *(uint8_t*) q;
+        if (l == UINT8_MAX)
+                /* avoid overflow right below */
+                return -EBADMSG;
+
+        r = message_peek_body(m, &rindex, 1, l+1, &q);
+        if (r < 0)
+                return r;
+
+        if (!validate_signature(q, l))
+                return -EBADMSG;
+
+        if (!streq(q, contents))
+                return -ENXIO;
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 1;
+}
+
+static int bus_message_enter_struct(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t l;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_valid(contents, false))
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        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 -ENXIO;
+
+        r = message_peek_body(m, &m->rindex, 8, 0, NULL);
+        if (r < 0)
+                return r;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + l + 1;
+
+        return 1;
+}
+
+static int bus_message_enter_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        size_t l;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_pair(contents))
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return 0;
+
+        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 -ENXIO;
+
+        r = message_peek_body(m, &m->rindex, 8, 0, NULL);
+        if (r < 0)
+                return r;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + l + 1;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_enter_container(sd_bus_message *m,
+                                            char type,
+                                            const char *contents) {
+        struct bus_container *c;
+        uint32_t *array_size = NULL;
+        _cleanup_free_ char *signature = NULL;
+        size_t before;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(type != 0 || !contents, -EINVAL);
+
+        if (type == 0 || !contents) {
+                const char *cc;
+                char tt;
+
+                /* Allow entering into anonymous containers */
+                r = sd_bus_message_peek_type(m, &tt, &cc);
+                if (r < 0)
+                        return r;
+
+                if (type != 0 && type != tt)
+                        return -ENXIO;
+
+                if (contents && !streq(contents, cc))
+                        return -ENXIO;
+
+                type = tt;
+                contents = cc;
+        }
+
+        /*
+         * We enforce a global limit on container depth, that is much
+         * higher than the 32 structs and 32 arrays the specification
+         * mandates. This is simpler to implement for us, and we need
+         * this only to ensure our container array doesn't grow
+         * without bounds. We are happy to return any data from a
+         * message as long as the data itself is valid, even if the
+         * overall message might be not.
+         *
+         * Note that the message signature is validated when
+         * parsing the headers, and that validation does check the
+         * 32/32 limit.
+         *
+         * Note that the specification defines no limits on the depth
+         * of stacked variants, but we do.
+         */
+        if (m->n_containers >= BUS_CONTAINER_DEPTH)
+                return -EBADMSG;
+
+        if (!GREEDY_REALLOC(m->containers, m->n_containers + 1))
+                return -ENOMEM;
+
+        if (message_end_of_signature(m))
+                return -ENXIO;
+
+        if (message_end_of_array(m, m->rindex))
+                return 0;
+
+        c = message_get_last_container(m);
+
+        signature = strdup(contents);
+        if (!signature)
+                return -ENOMEM;
+
+        c->saved_index = c->index;
+        before = m->rindex;
+
+        if (type == SD_BUS_TYPE_ARRAY)
+                r = bus_message_enter_array(m, c, contents, &array_size);
+        else if (type == SD_BUS_TYPE_VARIANT)
+                r = bus_message_enter_variant(m, c, contents);
+        else if (type == SD_BUS_TYPE_STRUCT)
+                r = bus_message_enter_struct(m, c, contents);
+        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                r = bus_message_enter_dict_entry(m, c, contents);
+        else
+                r = -EINVAL;
+        if (r <= 0)
+                return r;
+
+        /* OK, let's fill it in */
+        m->containers[m->n_containers++] = (struct bus_container) {
+                 .enclosing = type,
+                 .signature = TAKE_PTR(signature),
+
+                 .before = before,
+                 .begin = m->rindex,
+                 /* Unary type has fixed size of 1, but virtual size of 0 */
+                 .end = m->rindex,
+                 .array_size = array_size,
+        };
+
+        return 1;
+}
+
+_public_ int sd_bus_message_exit_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(m->n_containers > 0, -ENXIO);
+
+        c = message_get_last_container(m);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY) {
+                if (c->signature && c->signature[c->index] != 0)
+                        return -EBUSY;
+        }
+
+        if (c->enclosing == SD_BUS_TYPE_ARRAY) {
+                uint32_t l;
+
+                l = BUS_MESSAGE_BSWAP32(m, *c->array_size);
+                if (c->begin + l != m->rindex)
+                        return -EBUSY;
+        }
+
+        message_free_last_container(m);
+
+        return 1;
+}
+
+static void message_quit_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert(m);
+        assert(m->sealed);
+        assert(m->n_containers > 0);
+
+        /* Undo seeks */
+        c = message_get_last_container(m);
+        assert(m->rindex >= c->before);
+        m->rindex = c->before;
+
+        /* Free container */
+        message_free_last_container(m);
+
+        /* Correct index of new top-level container */
+        c = message_get_last_container(m);
+        c->index = c->saved_index;
+}
+
+_public_ int sd_bus_message_peek_type(sd_bus_message *m, char *type, const char **contents) {
+        struct bus_container *c;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (message_end_of_signature(m))
+                goto eof;
+
+        if (message_end_of_array(m, m->rindex))
+                goto eof;
+
+        c = message_get_last_container(m);
+
+        if (bus_type_is_basic(c->signature[c->index])) {
+                if (contents)
+                        *contents = NULL;
+                if (type)
+                        *type = c->signature[c->index];
+                return 1;
+        }
+
+        if (c->signature[c->index] == SD_BUS_TYPE_ARRAY) {
+
+                if (contents) {
+                        size_t l;
+
+                        r = signature_element_length(c->signature+c->index+1, &l);
+                        if (r < 0)
+                                return r;
+
+                        /* signature_element_length does verification internally */
+
+                        /* The array element must not be empty */
+                        assert(l >= 1);
+                        if (free_and_strndup(&c->peeked_signature,
+                                             c->signature + c->index + 1, l) < 0)
+                                return -ENOMEM;
+
+                        *contents = c->peeked_signature;
+                }
+
+                if (type)
+                        *type = SD_BUS_TYPE_ARRAY;
+
+                return 1;
+        }
+
+        if (IN_SET(c->signature[c->index], SD_BUS_TYPE_STRUCT_BEGIN, SD_BUS_TYPE_DICT_ENTRY_BEGIN)) {
+
+                if (contents) {
+                        size_t l;
+
+                        r = signature_element_length(c->signature+c->index, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 3);
+                        if (free_and_strndup(&c->peeked_signature,
+                                             c->signature + c->index + 1, l - 2) < 0)
+                                return -ENOMEM;
+
+                        *contents = c->peeked_signature;
+                }
+
+                if (type)
+                        *type = c->signature[c->index] == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY;
+
+                return 1;
+        }
+
+        if (c->signature[c->index] == SD_BUS_TYPE_VARIANT) {
+                if (contents) {
+                        size_t rindex, l;
+                        void *q;
+
+                        rindex = m->rindex;
+                        r = message_peek_body(m, &rindex, 1, 1, &q);
+                        if (r < 0)
+                                return r;
+
+                        l = *(uint8_t*) q;
+                        if (l == UINT8_MAX)
+                                /* avoid overflow right below */
+                                return -EBADMSG;
+
+                        r = message_peek_body(m, &rindex, 1, l+1, &q);
+                        if (r < 0)
+                                return r;
+
+                        if (!validate_signature(q, l))
+                                return -EBADMSG;
+
+                        *contents = q;
+                }
+
+                if (type)
+                        *type = SD_BUS_TYPE_VARIANT;
+
+                return 1;
+        }
+
+        return -EINVAL;
+
+eof:
+        if (type)
+                *type = 0;
+        if (contents)
+                *contents = NULL;
+        return 0;
+}
+
+_public_ int sd_bus_message_rewind(sd_bus_message *m, int complete) {
+        struct bus_container *c;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (complete) {
+                message_reset_containers(m);
+                m->rindex = 0;
+
+                c = message_get_last_container(m);
+        } else {
+                c = message_get_last_container(m);
+
+                c->index = 0;
+                m->rindex = c->begin;
+        }
+
+        return !isempty(c->signature);
+}
+
+_public_ int sd_bus_message_readv(
+                sd_bus_message *m,
+                const char *types,
+                va_list ap) {
+
+        unsigned n_array, n_struct;
+        TypeStack stack[BUS_CONTAINER_DEPTH];
+        unsigned stack_ptr = 0;
+        unsigned n_loop = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(types, -EINVAL);
+
+        if (isempty(types))
+                return 0;
+
+        /* Ideally, we'd just call ourselves recursively on every
+         * complex type. However, the state of a va_list that is
+         * passed to a function is undefined after that function
+         * returns. This means we need to decode the va_list linearly
+         * in a single stackframe. We hence implement our own
+         * home-grown stack in an array. */
+
+        n_array = UINT_MAX; /* length of current array entries */
+        n_struct = strlen(types); /* length of current struct contents signature */
+
+        for (;;) {
+                const char *t;
+
+                n_loop++;
+
+                if (n_array == 0 || (n_array == UINT_MAX && n_struct == 0)) {
+                        r = type_stack_pop(stack, ELEMENTSOF(stack), &stack_ptr, &types, &n_struct, &n_array);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                t = types;
+                if (n_array != UINT_MAX)
+                        n_array--;
+                else {
+                        types++;
+                        n_struct--;
+                }
+
+                switch (*t) {
+
+                case SD_BUS_TYPE_BYTE:
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_UNIX_FD: {
+                        void *p;
+
+                        p = va_arg(ap, void*);
+                        r = sd_bus_message_read_basic(m, *t, p);
+                        if (r < 0)
+                                return r;
+                        if (r == 0) {
+                                if (n_loop <= 1)
+                                        return 0;
+
+                                return -ENXIO;
+                        }
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_ARRAY: {
+                        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;
+
+                                r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0) {
+                                        if (n_loop <= 1)
+                                                return 0;
+
+                                        return -ENXIO;
+                                }
+                        }
+
+                        if (n_array == UINT_MAX) {
+                                types += k;
+                                n_struct -= k;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k;
+                        n_array = va_arg(ap, unsigned);
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_VARIANT: {
+                        const char *s;
+
+                        s = va_arg(ap, const char *);
+                        if (!s)
+                                return -EINVAL;
+
+                        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_VARIANT, s);
+                        if (r < 0)
+                                return r;
+                        if (r == 0) {
+                                if (n_loop <= 1)
+                                        return 0;
+
+                                return -ENXIO;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = s;
+                        n_struct = strlen(s);
+                        n_array = UINT_MAX;
+
+                        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;
+                        if (k < 2)
+                                return -ERANGE;
+
+                        {
+                                char s[k - 1];
+                                memcpy(s, t + 1, k - 2);
+                                s[k - 2] = 0;
+
+                                r = sd_bus_message_enter_container(m, *t == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0) {
+                                        if (n_loop <= 1)
+                                                return 0;
+                                        return -ENXIO;
+                                }
+                        }
+
+                        if (n_array == UINT_MAX) {
+                                types += k - 1;
+                                n_struct -= k - 1;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k - 2;
+                        n_array = UINT_MAX;
+
+                        break;
+                }
+
+                default:
+                        return -EINVAL;
+                }
+        }
+
+        return 1;
+}
+
+_public_ int sd_bus_message_read(sd_bus_message *m, const char *types, ...) {
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_message_readv(m, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_message_skip(sd_bus_message *m, const char *types) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        /* If types is NULL, read exactly one element */
+        if (!types) {
+                struct bus_container *c;
+                size_t l;
+
+                if (message_end_of_signature(m))
+                        return -ENXIO;
+
+                if (message_end_of_array(m, m->rindex))
+                        return 0;
+
+                c = message_get_last_container(m);
+
+                r = signature_element_length(c->signature + c->index, &l);
+                if (r < 0)
+                        return r;
+
+                types = strndupa_safe(c->signature + c->index, l);
+        }
+
+        switch (*types) {
+
+        case 0: /* Nothing to drop */
+                return 0;
+
+        case SD_BUS_TYPE_BYTE:
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+        case SD_BUS_TYPE_SIGNATURE:
+        case SD_BUS_TYPE_UNIX_FD:
+
+                r = sd_bus_message_read_basic(m, *types, NULL);
+                if (r <= 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, types + 1);
+                if (r < 0)
+                        return r;
+
+                return 1;
+
+        case SD_BUS_TYPE_ARRAY: {
+                size_t k;
+
+                r = signature_element_length(types + 1, &k);
+                if (r < 0)
+                        return r;
+
+                {
+                        char s[k+1];
+                        memcpy(s, types+1, k);
+                        s[k] = 0;
+
+                        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, s);
+                        if (r <= 0)
+                                return r;
+
+                        for (;;) {
+                                r = sd_bus_message_skip(m, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0)
+                                        break;
+                        }
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = sd_bus_message_skip(m, types + 1 + k);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        case SD_BUS_TYPE_VARIANT: {
+                const char *contents;
+                char x;
+
+                r = sd_bus_message_peek_type(m, &x, &contents);
+                if (r <= 0)
+                        return r;
+
+                if (x != SD_BUS_TYPE_VARIANT)
+                        return -ENXIO;
+
+                r = sd_bus_message_enter_container(m, SD_BUS_TYPE_VARIANT, contents);
+                if (r <= 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, contents);
+                if (r < 0)
+                        return r;
+                assert(r != 0);
+
+                r = sd_bus_message_exit_container(m);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, types + 1);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        case SD_BUS_TYPE_STRUCT_BEGIN:
+        case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                size_t k;
+
+                r = signature_element_length(types, &k);
+                if (r < 0)
+                        return r;
+                if (k < 2)
+                        return -ERANGE;
+
+                {
+                        char s[k-1];
+                        memcpy(s, types+1, k-2);
+                        s[k-2] = 0;
+
+                        r = sd_bus_message_enter_container(m, *types == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                        if (r <= 0)
+                                return r;
+
+                        r = sd_bus_message_skip(m, s);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = sd_bus_message_skip(m, types + k);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        default:
+                return -EINVAL;
+        }
+}
+
+_public_ int sd_bus_message_read_array(
+                sd_bus_message *m,
+                char type,
+                const void **ptr,
+                size_t *size) {
+
+        struct bus_container *c;
+        void *p;
+        size_t sz;
+        ssize_t align;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(ptr, -EINVAL);
+        assert_return(size, -EINVAL);
+        assert_return(!BUS_MESSAGE_NEED_BSWAP(m), -EOPNOTSUPP);
+
+        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                *ptr = NULL;
+                *size = 0;
+                return 0;
+        }
+
+        c = message_get_last_container(m);
+
+        align = bus_type_get_alignment(type);
+        if (align < 0)
+                return align;
+
+        sz = BUS_MESSAGE_BSWAP32(m, *c->array_size);
+
+        if (sz == 0)
+                /* Zero length array, let's return some aligned
+                 * pointer that is not NULL */
+                p = (uint8_t*) align;
+        else {
+                r = message_peek_body(m, &m->rindex, align, sz, &p);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = sd_bus_message_exit_container(m);
+        if (r < 0)
+                goto fail;
+
+        *ptr = (const void*) p;
+        *size = sz;
+
+        return 1;
+
+fail:
+        message_quit_container(m);
+        return r;
+}
+
+static int message_peek_fields(
+                sd_bus_message *m,
+                size_t *rindex,
+                size_t align,
+                size_t nbytes,
+                void **ret) {
+
+        size_t start, end;
+
+        assert(m);
+        assert(rindex);
+        assert(align > 0);
+
+        start = ALIGN_TO(*rindex, align);
+        if (start > m->fields_size)
+                return -EBADMSG;
+
+        /* Avoid overflow below */
+        if (nbytes > SIZE_MAX - start)
+                return -EBADMSG;
+
+        end = start + nbytes;
+        if (end > m->fields_size)
+                return -EBADMSG;
+
+        /* Verify that padding is 0 */
+        uint8_t *p = BUS_MESSAGE_FIELDS(m);
+        for (size_t k = *rindex; k < start; k++)
+                if (p[k] != 0)
+                        return -EBADMSG;
+
+        if (ret)
+                *ret = p + start;
+
+        *rindex = end;
+        return 1;
+}
+
+static int message_peek_field_uint32(
+                sd_bus_message *m,
+                size_t *ri,
+                size_t item_size,
+                uint32_t *ret) {
+
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        r = message_peek_fields(m, ri, 4, 4, &q);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+
+        return 0;
+}
+
+static int message_peek_field_string(
+                sd_bus_message *m,
+                bool (*validate)(const char *p),
+                size_t *ri,
+                size_t item_size,
+                const char **ret) {
+
+        uint32_t l;
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        r = message_peek_field_uint32(m, ri, 4, &l);
+        if (r < 0)
+                return r;
+
+        if (l == UINT32_MAX)
+                /* avoid overflow right below */
+                return -EBADMSG;
+
+        r = message_peek_fields(m, ri, 1, l+1, &q);
+        if (r < 0)
+                return r;
+
+        if (validate) {
+                if (!validate_nul(q, l))
+                        return -EBADMSG;
+
+                if (!validate(q))
+                        return -EBADMSG;
+        } else {
+                if (!validate_string(q, l))
+                        return -EBADMSG;
+        }
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static int message_peek_field_signature(
+                sd_bus_message *m,
+                size_t *ri,
+                size_t item_size,
+                const char **ret) {
+
+        size_t l;
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        r = message_peek_fields(m, ri, 1, 1, &q);
+        if (r < 0)
+                return r;
+
+        l = *(uint8_t*) q;
+        if (l == UINT8_MAX)
+                /* avoid overflow right below */
+                return -EBADMSG;
+
+        r = message_peek_fields(m, ri, 1, l+1, &q);
+        if (r < 0)
+                return r;
+
+        if (!validate_signature(q, l))
+                return -EBADMSG;
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static int message_skip_fields(
+                sd_bus_message *m,
+                size_t *ri,
+                uint32_t array_size,
+                const char **signature) {
+
+        size_t original_index;
+        int r;
+
+        assert(m);
+        assert(ri);
+        assert(signature);
+
+        original_index = *ri;
+
+        for (;;) {
+                char t;
+                size_t l;
+
+                if (array_size != UINT32_MAX &&
+                    array_size <= *ri - original_index)
+                        return 0;
+
+                t = **signature;
+                if (!t)
+                        return 0;
+
+                if (t == SD_BUS_TYPE_STRING) {
+
+                        r = message_peek_field_string(m, NULL, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_OBJECT_PATH) {
+
+                        r = message_peek_field_string(m, object_path_is_valid, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_SIGNATURE) {
+
+                        r = message_peek_field_signature(m, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (bus_type_is_basic(t)) {
+                        ssize_t align, k;
+
+                        align = bus_type_get_alignment(t);
+                        k = bus_type_get_size(t);
+                        assert(align > 0 && k > 0);
+
+                        r = message_peek_fields(m, ri, align, k, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_ARRAY) {
+
+                        r = signature_element_length(*signature + 1, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 1);
+                        {
+                                char sig[l + 1], *s = sig;
+                                uint32_t nas;
+                                int alignment;
+
+                                strncpy(sig, *signature + 1, l);
+                                sig[l] = '\0';
+
+                                alignment = bus_type_get_alignment(sig[0]);
+                                if (alignment < 0)
+                                        return alignment;
+
+                                r = message_peek_field_uint32(m, ri, 0, &nas);
+                                if (r < 0)
+                                        return r;
+                                if (nas > BUS_ARRAY_MAX_SIZE)
+                                        return -EBADMSG;
+
+                                r = message_peek_fields(m, ri, alignment, 0, NULL);
+                                if (r < 0)
+                                        return r;
+
+                                r = message_skip_fields(m, ri, nas, (const char**) &s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        (*signature) += 1 + l;
+
+                } else if (t == SD_BUS_TYPE_VARIANT) {
+                        const char *s;
+
+                        r = message_peek_field_signature(m, ri, 0, &s);
+                        if (r < 0)
+                                return r;
+
+                        r = message_skip_fields(m, ri, UINT32_MAX, (const char**) &s);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (IN_SET(t, SD_BUS_TYPE_STRUCT, SD_BUS_TYPE_DICT_ENTRY)) {
+
+                        r = signature_element_length(*signature, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 2);
+                        {
+                                char sig[l + 1], *s = sig;
+                                strncpy(sig, *signature + 1, l);
+                                sig[l] = '\0';
+
+                                r = message_skip_fields(m, ri, UINT32_MAX, (const char**) &s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        *signature += l;
+                } else
+                        return -EBADMSG;
+        }
+}
+
+static int message_parse_fields(sd_bus_message *m) {
+        uint32_t unix_fds = 0;
+        bool unix_fds_set = false;
+        int r;
+
+        assert(m);
+
+        m->user_body_size = m->body_size;
+
+        for (size_t ri = 0; ri < m->fields_size; ) {
+                const char *signature;
+                uint64_t field_type;
+                size_t item_size = SIZE_MAX;
+                uint8_t *u8;
+
+                r = message_peek_fields(m, &ri, 8, 1, (void**) &u8);
+                if (r < 0)
+                        return r;
+
+                field_type = *u8;
+
+                r = message_peek_field_signature(m, &ri, 0, &signature);
+                if (r < 0)
+                        return r;
+
+                switch (field_type) {
+
+                case _BUS_MESSAGE_HEADER_INVALID:
+                        return -EBADMSG;
+
+                case BUS_MESSAGE_HEADER_PATH:
+
+                        if (m->path)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "o"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, object_path_is_valid, &ri, item_size, &m->path);
+                        break;
+
+                case BUS_MESSAGE_HEADER_INTERFACE:
+
+                        if (m->interface)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, interface_name_is_valid, &ri, item_size, &m->interface);
+                        break;
+
+                case BUS_MESSAGE_HEADER_MEMBER:
+
+                        if (m->member)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, member_name_is_valid, &ri, item_size, &m->member);
+                        break;
+
+                case BUS_MESSAGE_HEADER_ERROR_NAME:
+
+                        if (m->error.name)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, error_name_is_valid, &ri, item_size, &m->error.name);
+                        if (r >= 0)
+                                m->error._need_free = -1;
+
+                        break;
+
+                case BUS_MESSAGE_HEADER_DESTINATION:
+
+                        if (m->destination)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, service_name_is_valid, &ri, item_size, &m->destination);
+                        break;
+
+                case BUS_MESSAGE_HEADER_SENDER:
+
+                        if (m->sender)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, service_name_is_valid, &ri, item_size, &m->sender);
+
+                        if (r >= 0 && m->sender[0] == ':' && m->bus->bus_client) {
+                                m->creds.unique_name = (char*) m->sender;
+                                m->creds.mask |= SD_BUS_CREDS_UNIQUE_NAME & m->bus->creds_mask;
+                        }
+
+                        break;
+
+                case BUS_MESSAGE_HEADER_SIGNATURE: {
+                        const char *s;
+                        char *c;
+
+                        if (m->root_container.signature)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "g"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_signature(m, &ri, item_size, &s);
+                        if (r < 0)
+                                return r;
+
+                        c = strdup(s);
+                        if (!c)
+                                return -ENOMEM;
+
+                        free_and_replace(m->root_container.signature, c);
+                        break;
+                }
+
+                case BUS_MESSAGE_HEADER_REPLY_SERIAL: {
+                        uint32_t serial;
+
+                        if (m->reply_cookie != 0)
+                                return -EBADMSG;
+
+
+                        if (!streq(signature, "u"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_uint32(m, &ri, item_size, &serial);
+                        if (r < 0)
+                                return r;
+
+                        m->reply_cookie = serial;
+
+                        if (m->reply_cookie == 0)
+                                return -EBADMSG;
+
+                        break;
+                }
+                case BUS_MESSAGE_HEADER_UNIX_FDS:
+                        if (unix_fds_set)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "u"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_uint32(m, &ri, item_size, &unix_fds);
+                        if (r < 0)
+                                return -EBADMSG;
+
+                        unix_fds_set = true;
+                        break;
+
+                default:
+                        r = message_skip_fields(m, &ri, UINT32_MAX, (const char **) &signature);
+                }
+                if (r < 0)
+                        return r;
+        }
+
+        if (m->n_fds != unix_fds)
+                return -EBADMSG;
+
+        switch (m->header->type) {
+
+        case SD_BUS_MESSAGE_SIGNAL:
+                if (!m->path || !m->interface || !m->member)
+                        return -EBADMSG;
+
+                if (m->reply_cookie != 0)
+                        return -EBADMSG;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_CALL:
+
+                if (!m->path || !m->member)
+                        return -EBADMSG;
+
+                if (m->reply_cookie != 0)
+                        return -EBADMSG;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_RETURN:
+
+                if (m->reply_cookie == 0)
+                        return -EBADMSG;
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_ERROR:
+
+                if (m->reply_cookie == 0 || !m->error.name)
+                        return -EBADMSG;
+                break;
+        }
+
+        /* Refuse non-local messages that claim they are local */
+        if (streq_ptr(m->path, "/org/freedesktop/DBus/Local"))
+                return -EBADMSG;
+        if (streq_ptr(m->interface, "org.freedesktop.DBus.Local"))
+                return -EBADMSG;
+        if (streq_ptr(m->sender, "org.freedesktop.DBus.Local"))
+                return -EBADMSG;
+
+        m->root_container.end = m->user_body_size;
+
+        /* Try to read the error message, but if we can't it's a non-issue */
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_ERROR)
+                (void) sd_bus_message_read(m, "s", &m->error.message);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_destination(sd_bus_message *m, const char *destination) {
+        assert_return(m, -EINVAL);
+        assert_return(destination, -EINVAL);
+        assert_return(service_name_is_valid(destination), -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->destination, -EEXIST);
+
+        return message_append_field_string(m, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &m->destination);
+}
+
+_public_ int sd_bus_message_set_sender(sd_bus_message *m, const char *sender) {
+        assert_return(m, -EINVAL);
+        assert_return(sender, -EINVAL);
+        assert_return(service_name_is_valid(sender), -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->sender, -EEXIST);
+
+        return message_append_field_string(m, BUS_MESSAGE_HEADER_SENDER, SD_BUS_TYPE_STRING, sender, &m->sender);
+}
+
+int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz) {
+        size_t total;
+        void *p, *e;
+        size_t i;
+        struct bus_body_part *part;
+
+        assert(m);
+        assert(buffer);
+        assert(sz);
+
+        total = BUS_MESSAGE_SIZE(m);
+
+        p = malloc(total);
+        if (!p)
+                return -ENOMEM;
+
+        e = mempcpy(p, m->header, BUS_MESSAGE_BODY_BEGIN(m));
+        MESSAGE_FOREACH_PART(part, i, m)
+                e = mempcpy(e, part->data, part->size);
+
+        assert(total == (size_t) ((uint8_t*) e - (uint8_t*) p));
+
+        *buffer = p;
+        *sz = total;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_read_strv_extend(sd_bus_message *m, char ***l) {
+        char type;
+        const char *contents, *s;
+        int r;
+
+        assert(m);
+        assert(l);
+
+        r = sd_bus_message_peek_type(m, &type, &contents);
+        if (r < 0)
+                return r;
+
+        if (type != SD_BUS_TYPE_ARRAY || !STR_IN_SET(contents, "s", "o", "g"))
+                return -ENXIO;
+
+        r = sd_bus_message_enter_container(m, 'a', NULL);
+        if (r <= 0)
+                return r;
+
+        /* sd_bus_message_read_basic() does content validation for us. */
+        while ((r = sd_bus_message_read_basic(m, *contents, &s)) > 0) {
+                r = strv_extend(l, s);
+                if (r < 0)
+                        return r;
+        }
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_exit_container(m);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_read_strv(sd_bus_message *m, char ***l) {
+        _cleanup_strv_free_ char **strv = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(l, -EINVAL);
+
+        r = sd_bus_message_read_strv_extend(m, &strv);
+        if (r <= 0)
+                return r;
+
+        *l = TAKE_PTR(strv);
+        return 1;
+}
+
+static int bus_message_get_arg_skip(
+                sd_bus_message *m,
+                unsigned i,
+                char *_type,
+                const char **_contents) {
+
+        unsigned j;
+        int r;
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        for (j = 0;; j++) {
+                const char *contents;
+                char type;
+
+                r = sd_bus_message_peek_type(m, &type, &contents);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ENXIO;
+
+                /* Don't match against arguments after the first one we don't understand */
+                if (!IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE) &&
+                    !(type == SD_BUS_TYPE_ARRAY && STR_IN_SET(contents, "s", "o", "g")))
+                        return -ENXIO;
+
+                if (j >= i) {
+                        if (_contents)
+                                *_contents = contents;
+                        if (_type)
+                                *_type = type;
+                        return 0;
+                }
+
+                r = sd_bus_message_skip(m, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+}
+
+int bus_message_get_arg(sd_bus_message *m, unsigned i, const char **str) {
+        char type;
+        int r;
+
+        assert(m);
+        assert(str);
+
+        r = bus_message_get_arg_skip(m, i, &type, NULL);
+        if (r < 0)
+                return r;
+
+        if (!IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE))
+                return -ENXIO;
+
+        return sd_bus_message_read_basic(m, type, str);
+}
+
+int bus_message_get_arg_strv(sd_bus_message *m, unsigned i, char ***strv) {
+        const char *contents;
+        char type;
+        int r;
+
+        assert(m);
+        assert(strv);
+
+        r = bus_message_get_arg_skip(m, i, &type, &contents);
+        if (r < 0)
+                return r;
+
+        if (type != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+        if (!STR_IN_SET(contents, "s", "o", "g"))
+                return -ENXIO;
+
+        return sd_bus_message_read_strv(m, strv);
+}
+
+_public_ int sd_bus_message_get_errno(sd_bus_message *m) {
+        assert_return(m, EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
+                return 0;
+
+        return sd_bus_error_get_errno(&m->error);
+}
+
+_public_ const char* sd_bus_message_get_signature(sd_bus_message *m, int complete) {
+        struct bus_container *c;
+
+        assert_return(m, NULL);
+
+        c = complete ? &m->root_container : message_get_last_container(m);
+        return strempty(c->signature);
+}
+
+_public_ int sd_bus_message_is_empty(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return isempty(m->root_container.signature);
+}
+
+_public_ int sd_bus_message_has_signature(sd_bus_message *m, const char *signature) {
+        assert_return(m, -EINVAL);
+
+        return streq(strempty(m->root_container.signature), strempty(signature));
+}
+
+_public_ int sd_bus_message_copy(sd_bus_message *m, sd_bus_message *source, int all) {
+        bool done_something = false;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(source, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(source->sealed, -EPERM);
+
+        do {
+                const char *contents;
+                char type;
+                union {
+                        uint8_t u8;
+                        uint16_t u16;
+                        int16_t s16;
+                        uint32_t u32;
+                        int32_t s32;
+                        uint64_t u64;
+                        int64_t s64;
+                        double d64;
+                        const char *string;
+                        int i;
+                } basic;
+
+                r = sd_bus_message_peek_type(source, &type, &contents);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                done_something = true;
+
+                if (bus_type_is_container(type) > 0) {
+
+                        r = sd_bus_message_enter_container(source, type, contents);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_open_container(m, type, contents);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_copy(m, source, true);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_close_container(m);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_exit_container(source);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                r = sd_bus_message_read_basic(source, type, &basic);
+                if (r < 0)
+                        return r;
+
+                assert(r > 0);
+
+                if (IN_SET(type, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE, SD_BUS_TYPE_STRING))
+                        r = sd_bus_message_append_basic(m, type, basic.string);
+                else
+                        r = sd_bus_message_append_basic(m, type, &basic);
+
+                if (r < 0)
+                        return r;
+
+        } while (all);
+
+        return done_something;
+}
+
+_public_ int sd_bus_message_verify_type(sd_bus_message *m, char type, const char *contents) {
+        const char *c;
+        char t;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(!type || bus_type_is_valid(type), -EINVAL);
+        assert_return(!contents || signature_is_valid(contents, true), -EINVAL);
+        assert_return(type || contents, -EINVAL);
+        assert_return(!contents || !type || bus_type_is_container(type), -EINVAL);
+
+        r = sd_bus_message_peek_type(m, &t, &c);
+        if (r <= 0)
+                return r;
+
+        if (type != 0 && type != t)
+                return 0;
+
+        if (contents && !streq_ptr(contents, c))
+                return 0;
+
+        return 1;
+}
+
+_public_ sd_bus *sd_bus_message_get_bus(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->bus;
+}
+
+int bus_message_remarshal(sd_bus *bus, sd_bus_message **m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *n = NULL;
+        usec_t timeout;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(*m);
+
+        switch ((*m)->header->type) {
+
+        case SD_BUS_MESSAGE_SIGNAL:
+                r = sd_bus_message_new_signal(bus, &n, (*m)->path, (*m)->interface, (*m)->member);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_CALL:
+                r = sd_bus_message_new_method_call(bus, &n, (*m)->destination, (*m)->path, (*m)->interface, (*m)->member);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_RETURN:
+        case SD_BUS_MESSAGE_METHOD_ERROR:
+
+                r = sd_bus_message_new(bus, &n, (*m)->header->type);
+                if (r < 0)
+                        return -ENOMEM;
+
+                assert(n);
+
+                n->reply_cookie = (*m)->reply_cookie;
+
+                r = message_append_reply_cookie(n, n->reply_cookie);
+                if (r < 0)
+                        return r;
+
+                if ((*m)->header->type == SD_BUS_MESSAGE_METHOD_ERROR && (*m)->error.name) {
+                        r = message_append_field_string(n, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, (*m)->error.name, &n->error.message);
+                        if (r < 0)
+                                return r;
+
+                        n->error._need_free = -1;
+                }
+
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        if ((*m)->destination && !n->destination) {
+                r = message_append_field_string(n, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, (*m)->destination, &n->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        if ((*m)->sender && !n->sender) {
+                r = message_append_field_string(n, BUS_MESSAGE_HEADER_SENDER, SD_BUS_TYPE_STRING, (*m)->sender, &n->sender);
+                if (r < 0)
+                        return r;
+        }
+
+        n->header->flags |= (*m)->header->flags & (BUS_MESSAGE_NO_REPLY_EXPECTED|BUS_MESSAGE_NO_AUTO_START);
+
+        r = sd_bus_message_copy(n, *m, true);
+        if (r < 0)
+                return r;
+
+        timeout = (*m)->timeout;
+        if (timeout == 0 && !((*m)->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)) {
+                r = sd_bus_get_method_call_timeout(bus, &timeout);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_seal(n, BUS_MESSAGE_COOKIE(*m), timeout);
+        if (r < 0)
+                return r;
+
+        sd_bus_message_unref(*m);
+        *m = TAKE_PTR(n);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_get_priority(sd_bus_message *m, int64_t *priority) {
+        static bool warned = false;
+
+        assert_return(m, -EINVAL);
+        assert_return(priority, -EINVAL);
+
+        if (!warned) {
+                log_debug("sd_bus_message_get_priority() is deprecated and always returns 0.");
+                warned = true;
+        }
+
+        *priority = 0;
+        return 0;
+}
+
+_public_ int sd_bus_message_set_priority(sd_bus_message *m, int64_t priority) {
+        static bool warned = false;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        if (!warned) {
+                log_debug("sd_bus_message_set_priority() is deprecated and does nothing.");
+                warned = true;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_sensitive(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        m->sensitive = true;
+        return 0;
+}