chiark / gitweb /
bus: fix hello ioctl buffer size calculation
[elogind.git] / src / libsystemd-bus / bus-kernel.c
index 8ef5752b311ce5cd237f88c19f3fedc5f881b998..05544e1e477403716292383feef0cdcaaa2ab2e1 100644 (file)
 #include <sys/mman.h>
 
 #include "util.h"
+#include "strv.h"
 
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-kernel.h"
 #include "bus-bloom.h"
+#include "bus-util.h"
 
-#define KDBUS_ITEM_NEXT(item) \
-        (typeof(item))(((uint8_t *)item) + ALIGN8((item)->size))
+#define UNIQUE_NAME_MAX (3+DECIMAL_STR_MAX(uint64_t))
 
-#define KDBUS_ITEM_FOREACH(item, head)                                          \
-        for (item = (head)->items;                                              \
-             (uint8_t *)(item) < (uint8_t *)(head) + (head)->size;              \
-             item = KDBUS_ITEM_NEXT(item))
-
-#define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data)
-#define KDBUS_ITEM_SIZE(s) ALIGN8((s) + KDBUS_ITEM_HEADER_SIZE)
-
-#define KDBUS_POOL_SIZE (4*1024*1024)
-
-static int parse_unique_name(const char *s, uint64_t *id) {
+int bus_kernel_parse_unique_name(const char *s, uint64_t *id) {
         int r;
 
         assert(s);
@@ -74,7 +65,7 @@ static void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz)
          * conditions */
 
         (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec);
-        (*d)->type = KDBUS_MSG_PAYLOAD_VEC;
+        (*d)->type = KDBUS_ITEM_PAYLOAD_VEC;
         (*d)->vec.address = PTR_TO_UINT64(p);
         (*d)->vec.size = sz;
 
@@ -88,7 +79,7 @@ static void append_payload_memfd(struct kdbus_item **d, int memfd, size_t sz) {
 
         *d = ALIGN8_PTR(*d);
         (*d)->size = offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd);
-        (*d)->type = KDBUS_MSG_PAYLOAD_MEMFD;
+        (*d)->type = KDBUS_ITEM_PAYLOAD_MEMFD;
         (*d)->memfd.fd = memfd;
         (*d)->memfd.size = sz;
 
@@ -102,7 +93,7 @@ static void append_destination(struct kdbus_item **d, const char *s, size_t leng
         *d = ALIGN8_PTR(*d);
 
         (*d)->size = offsetof(struct kdbus_item, str) + length + 1;
-        (*d)->type = KDBUS_MSG_DST_NAME;
+        (*d)->type = KDBUS_ITEM_DST_NAME;
         memcpy((*d)->str, s, length + 1);
 
         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
@@ -116,7 +107,7 @@ static void* append_bloom(struct kdbus_item **d, size_t length) {
         *d = ALIGN8_PTR(*d);
 
         (*d)->size = offsetof(struct kdbus_item, data) + length;
-        (*d)->type = KDBUS_MSG_BLOOM;
+        (*d)->type = KDBUS_ITEM_BLOOM;
         r = (*d)->data;
 
         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
@@ -131,7 +122,7 @@ static void append_fds(struct kdbus_item **d, const int fds[], unsigned n_fds) {
 
         *d = ALIGN8_PTR(*d);
         (*d)->size = offsetof(struct kdbus_item, fds) + sizeof(int) * n_fds;
-        (*d)->type = KDBUS_MSG_FDS;
+        (*d)->type = KDBUS_ITEM_FDS;
         memcpy((*d)->fds, fds, sizeof(int) * n_fds);
 
         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
@@ -154,6 +145,7 @@ static int bus_message_setup_bloom(sd_bus_message *m, void *bloom) {
                 bloom_add_pair(bloom, "member", m->member);
         if (m->path) {
                 bloom_add_pair(bloom, "path", m->path);
+                bloom_add_pair(bloom, "path-slash-prefix", m->path);
                 bloom_add_prefixes(bloom, "path-slash-prefix", m->path, '/');
         }
 
@@ -217,7 +209,7 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
                 return 0;
 
         if (m->destination) {
-                r = parse_unique_name(m->destination, &unique);
+                r = bus_kernel_parse_unique_name(m->destination, &unique);
                 if (r < 0)
                         return r;
 
@@ -257,12 +249,12 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
         memset(m->kdbus, 0, sz);
 
         m->kdbus->flags =
-                ((m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED) ? 0 : KDBUS_MSG_FLAGS_EXPECT_REPLY) |
-                ((m->header->flags & SD_BUS_MESSAGE_NO_AUTO_START) ? KDBUS_MSG_FLAGS_NO_AUTO_START : 0);
+                ((m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) ? 0 : KDBUS_MSG_FLAGS_EXPECT_REPLY) |
+                ((m->header->flags & BUS_MESSAGE_NO_AUTO_START) ? KDBUS_MSG_FLAGS_NO_AUTO_START : 0);
         m->kdbus->dst_id =
                 well_known ? 0 :
                 m->destination ? unique : KDBUS_DST_ID_BROADCAST;
-        m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS1;
+        m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS;
         m->kdbus->cookie = m->header->serial;
 
         m->kdbus->timeout_ns = m->timeout * NSEC_PER_USEC;
@@ -325,12 +317,9 @@ fail:
 }
 
 int bus_kernel_take_fd(sd_bus *b) {
-        uint8_t h[ALIGN8(sizeof(struct kdbus_cmd_hello)) +
-                  ALIGN8(KDBUS_ITEM_HEADER_SIZE) +
-                  ALIGN8(sizeof(struct kdbus_vec))] = {};
-
-        struct kdbus_cmd_hello *hello = (struct kdbus_cmd_hello*) h;
-
+        struct kdbus_cmd_hello *hello;
+        struct kdbus_item *item;
+        size_t l = 0, sz;
         int r;
 
         assert(b);
@@ -338,34 +327,51 @@ int bus_kernel_take_fd(sd_bus *b) {
         if (b->is_server)
                 return -EINVAL;
 
-        if (!b->kdbus_buffer) {
-                b->kdbus_buffer = mmap(NULL, KDBUS_POOL_SIZE, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
-                if (b->kdbus_buffer == MAP_FAILED) {
-                        b->kdbus_buffer = NULL;
-                        return -errno;
-                }
+        b->use_memfd = 1;
+
+        sz = ALIGN8(offsetof(struct kdbus_cmd_hello, items));
+
+        if (b->fake_creds_valid)
+                sz += ALIGN8(offsetof(struct kdbus_item, creds)) + sizeof(struct kdbus_creds);
+
+        if (b->fake_label) {
+                l = strlen(b->fake_label);
+                sz += ALIGN8(offsetof(struct kdbus_item, str) + l + 1);
         }
 
-        hello->size = sizeof(h);
-        hello->conn_flags =
-                KDBUS_HELLO_ACCEPT_FD|
-                KDBUS_HELLO_ATTACH_COMM|
-                KDBUS_HELLO_ATTACH_EXE|
-                KDBUS_HELLO_ATTACH_CMDLINE|
-                KDBUS_HELLO_ATTACH_CGROUP|
-                KDBUS_HELLO_ATTACH_CAPS|
-                KDBUS_HELLO_ATTACH_SECLABEL|
-                KDBUS_HELLO_ATTACH_AUDIT;
+        hello = alloca0(sz);
+        hello->size = sz;
+        hello->conn_flags = b->hello_flags;
+        hello->attach_flags = b->attach_flags;
+        hello->pool_size = KDBUS_POOL_SIZE;
+
+        item = hello->items;
+
+        if (b->fake_creds_valid) {
+                item->size = offsetof(struct kdbus_item, creds) + sizeof(struct kdbus_creds);
+                item->type = KDBUS_ITEM_CREDS;
+                item->creds = b->fake_creds;
 
-        hello->items[0].type = KDBUS_HELLO_POOL;
-        hello->items[0].size = KDBUS_ITEM_HEADER_SIZE + sizeof(struct kdbus_vec);
-        hello->items[0].vec.address = (uint64_t) b->kdbus_buffer;
-        hello->items[0].vec.size = KDBUS_POOL_SIZE;
+                item = KDBUS_ITEM_NEXT(item);
+        }
+
+        if (b->fake_label) {
+                item->size = offsetof(struct kdbus_item, str) + l + 1;
+                memcpy(item->str, b->fake_label, l+1);
+        }
 
         r = ioctl(b->input_fd, KDBUS_CMD_HELLO, hello);
         if (r < 0)
                 return -errno;
 
+        if (!b->kdbus_buffer) {
+                b->kdbus_buffer = mmap(NULL, KDBUS_POOL_SIZE, PROT_READ, MAP_SHARED, b->input_fd, 0);
+                if (b->kdbus_buffer == MAP_FAILED) {
+                        b->kdbus_buffer = NULL;
+                        return -errno;
+                }
+        }
+
         /* The higher 32bit of both flags fields are considered
          * 'incompatible flags'. Refuse them all for now. */
         if (hello->bus_flags > 0xFFFFFFFFULL ||
@@ -378,15 +384,18 @@ int bus_kernel_take_fd(sd_bus *b) {
         if (asprintf(&b->unique_name, ":1.%llu", (unsigned long long) hello->id) < 0)
                 return -ENOMEM;
 
+        b->unique_id = hello->id;
+
         b->is_kernel = true;
         b->bus_client = true;
-        b->can_fds = true;
+        b->can_fds = !!(hello->conn_flags & KDBUS_HELLO_ACCEPT_FD);
+        b->message_version = 2;
+        b->message_endian = BUS_NATIVE_ENDIAN;
 
-        r = bus_start_running(b);
-        if (r < 0)
-                return r;
+        /* the kernel told us the UUID of the underlying bus */
+        memcpy(b->server_id.bytes, hello->id128, sizeof(b->server_id.bytes));
 
-        return 1;
+        return bus_start_running(b);
 }
 
 int bus_kernel_connect(sd_bus *b) {
@@ -414,35 +423,224 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) {
         assert(m);
         assert(bus->state == BUS_RUNNING);
 
+        /* If we can't deliver, we want room for the error message */
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
         r = bus_message_setup_kmsg(bus, m);
         if (r < 0)
                 return r;
 
         r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus);
-        if (r < 0)
-                return errno == EAGAIN ? 0 : -errno;
+        if (r < 0) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                sd_bus_message *reply;
+
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+                else if (errno == ENXIO || errno == ESRCH) {
+
+                        /* ENXIO: unique name not known
+                         * ESRCH: well-known name not known */
+
+                        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL)
+                                sd_bus_error_setf(&error, SD_BUS_ERROR_SERVICE_UNKNOWN, "Destination %s not known", m->destination);
+                        else {
+                                log_debug("Could not deliver message to %s as destination is not known. Ignoring.", m->destination);
+                                return 0;
+                        }
+
+                } else if (errno == EADDRNOTAVAIL) {
+
+                        /* EADDRNOTAVAIL: activation is possible, but turned off in request flags */
+
+                        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL)
+                                sd_bus_error_setf(&error, SD_BUS_ERROR_SERVICE_UNKNOWN, "Activation of %s not requested", m->destination);
+                        else {
+                                log_debug("Could not deliver message to %s as destination is not activated. Ignoring.", m->destination);
+                                return 0;
+                        }
+                } else
+                        return -errno;
+
+                r = bus_message_new_synthetic_error(
+                                bus,
+                                BUS_MESSAGE_SERIAL(m),
+                                &error,
+                                &reply);
+
+                if (r < 0)
+                        return r;
+
+                r = bus_seal_synthetic_message(bus, reply);
+                if (r < 0)
+                        return r;
+
+                bus->rqueue[bus->rqueue_size++] = reply;
+
+                return 0;
+        }
 
         return 1;
 }
 
 static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
+        uint64_t off;
         struct kdbus_item *d;
 
         assert(bus);
         assert(k);
 
-        ioctl(bus->input_fd, KDBUS_CMD_MSG_RELEASE, k);
+        off = (uint8_t *)k - (uint8_t *)bus->kdbus_buffer;
+        ioctl(bus->input_fd, KDBUS_CMD_FREE, &off);
 
-        KDBUS_ITEM_FOREACH(d, k) {
+        KDBUS_ITEM_FOREACH(d, k, items) {
 
-                if (d->type == KDBUS_MSG_FDS)
+                if (d->type == KDBUS_ITEM_FDS)
                         close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
-                else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD)
+                else if (d->type == KDBUS_ITEM_PAYLOAD_MEMFD)
                         close_nointr_nofail(d->memfd.fd);
         }
 }
 
-static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_message **ret) {
+static int push_name_owner_changed(sd_bus *bus, const char *name, const char *old_owner, const char *new_owner) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        r = sd_bus_message_new_signal(
+                        bus,
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "NameOwnerChanged",
+                        &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "sss", name, old_owner, new_owner);
+        if (r < 0)
+                return r;
+
+        m->sender = "org.freedesktop.DBus";
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        bus->rqueue[bus->rqueue_size++] = m;
+        m = NULL;
+
+        return 1;
+}
+
+static int translate_name_change(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *d) {
+        char new_owner[UNIQUE_NAME_MAX], old_owner[UNIQUE_NAME_MAX];
+
+        assert(bus);
+        assert(k);
+        assert(d);
+
+        if (d->type == KDBUS_ITEM_NAME_ADD || (d->name_change.old.flags & (KDBUS_NAME_IN_QUEUE|KDBUS_NAME_ACTIVATOR)))
+                old_owner[0] = 0;
+        else
+                sprintf(old_owner, ":1.%llu", (unsigned long long) d->name_change.old.id);
+
+        if (d->type == KDBUS_ITEM_NAME_REMOVE || (d->name_change.new.flags & (KDBUS_NAME_IN_QUEUE|KDBUS_NAME_ACTIVATOR))) {
+
+                if (isempty(old_owner))
+                        return 0;
+
+                new_owner[0] = 0;
+        } else
+                sprintf(new_owner, ":1.%llu", (unsigned long long) d->name_change.new.id);
+
+        return push_name_owner_changed(bus, d->name_change.name, old_owner, new_owner);
+}
+
+static int translate_id_change(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *d) {
+        char owner[UNIQUE_NAME_MAX];
+
+        assert(bus);
+        assert(k);
+        assert(d);
+
+        sprintf(owner, ":1.%llu", d->id_change.id);
+
+        return push_name_owner_changed(
+                        bus, owner,
+                        d->type == KDBUS_ITEM_ID_ADD ? NULL : owner,
+                        d->type == KDBUS_ITEM_ID_ADD ? owner : NULL);
+}
+
+static int translate_reply(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *d) {
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+        assert(k);
+        assert(d);
+
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        k->cookie_reply,
+                        d->type == KDBUS_ITEM_REPLY_TIMEOUT ?
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Method call timed out") :
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Method call peer died"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        m->sender = "org.freedesktop.DBus";
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        bus->rqueue[bus->rqueue_size++] = m;
+        m = NULL;
+
+        return 1;
+}
+
+static int bus_kernel_translate_message(sd_bus *bus, struct kdbus_msg *k) {
+        struct kdbus_item *d, *found = NULL;
+
+        static int (* const translate[])(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *d) = {
+                [KDBUS_ITEM_NAME_ADD - _KDBUS_ITEM_KERNEL_BASE] = translate_name_change,
+                [KDBUS_ITEM_NAME_REMOVE - _KDBUS_ITEM_KERNEL_BASE] = translate_name_change,
+                [KDBUS_ITEM_NAME_CHANGE - _KDBUS_ITEM_KERNEL_BASE] = translate_name_change,
+
+                [KDBUS_ITEM_ID_ADD - _KDBUS_ITEM_KERNEL_BASE] = translate_id_change,
+                [KDBUS_ITEM_ID_REMOVE - _KDBUS_ITEM_KERNEL_BASE] = translate_id_change,
+
+                [KDBUS_ITEM_REPLY_TIMEOUT - _KDBUS_ITEM_KERNEL_BASE] = translate_reply,
+                [KDBUS_ITEM_REPLY_DEAD - _KDBUS_ITEM_KERNEL_BASE] = translate_reply,
+        };
+
+        assert(bus);
+        assert(k);
+        assert(k->payload_type == KDBUS_PAYLOAD_KERNEL);
+
+        KDBUS_ITEM_FOREACH(d, k, items) {
+                if (d->type >= _KDBUS_ITEM_KERNEL_BASE && d->type < _KDBUS_ITEM_KERNEL_BASE + ELEMENTSOF(translate)) {
+                        if (found)
+                                return -EBADMSG;
+                        found = d;
+                } else
+                        log_debug("Got unknown field from kernel %llu", d->type);
+        }
+
+        if (!found) {
+                log_debug("Didn't find a kernel message to translate.");
+                return 0;
+        }
+
+        return translate[found->type - _KDBUS_ITEM_KERNEL_BASE](bus, k, found);
+}
+
+static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
         sd_bus_message *m = NULL;
         struct kdbus_item *d;
         unsigned n_fds = 0;
@@ -454,35 +652,34 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
 
         assert(bus);
         assert(k);
-        assert(ret);
+        assert(k->payload_type == KDBUS_PAYLOAD_DBUS);
 
-        if (k->payload_type != KDBUS_PAYLOAD_DBUS1)
-                return 0;
-
-        KDBUS_ITEM_FOREACH(d, k) {
+        KDBUS_ITEM_FOREACH(d, k, items) {
                 size_t l;
 
                 l = d->size - offsetof(struct kdbus_item, data);
 
-                if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
+                switch (d->type) {
 
+                case KDBUS_ITEM_PAYLOAD_OFF:
                         if (!h) {
-                                h = UINT64_TO_PTR(d->vec.address);
+                                h = (struct bus_header *)((uint8_t *)k + d->vec.offset);
 
                                 if (!bus_header_is_complete(h, d->vec.size))
                                         return -EBADMSG;
                         }
 
                         n_bytes += d->vec.size;
+                        break;
 
-                } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
-
+                case KDBUS_ITEM_PAYLOAD_MEMFD:
                         if (!h)
                                 return -EBADMSG;
 
                         n_bytes += d->memfd.size;
+                        break;
 
-                } else if (d->type == KDBUS_MSG_FDS) {
+                case KDBUS_ITEM_FDS: {
                         int *f;
                         unsigned j;
 
@@ -494,9 +691,13 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                         fds = f;
                         memcpy(fds + n_fds, d->fds, sizeof(int) * j);
                         n_fds += j;
+                        break;
+                }
 
-                } else if (d->type == KDBUS_MSG_SRC_SECLABEL)
+                case KDBUS_ITEM_SECLABEL:
                         seclabel = d->str;
+                        break;
+                }
         }
 
         if (!h)
@@ -509,16 +710,31 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
         if (n_bytes != total)
                 return -EBADMSG;
 
-        r = bus_message_from_header(h, sizeof(struct bus_header), fds, n_fds, NULL, seclabel, 0, &m);
+        /* on kdbus we only speak native endian gvariant, never dbus1
+         * marshalling or reverse endian */
+        if (h->version != 2 ||
+            h->endian != BUS_NATIVE_ENDIAN)
+                return -EPROTOTYPE;
+
+        r = bus_message_from_header(bus, h, sizeof(struct bus_header), fds, n_fds, NULL, seclabel, 0, &m);
         if (r < 0)
                 return r;
 
-        KDBUS_ITEM_FOREACH(d, k) {
+        /* The well-known names list is different from the other
+        credentials. If we asked for it, but nothing is there, this
+        means that the list of well-known names is simply empty, not
+        that we lack any data */
+
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+
+        KDBUS_ITEM_FOREACH(d, k, items) {
                 size_t l;
 
                 l = d->size - offsetof(struct kdbus_item, data);
 
-                if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
+                switch (d->type) {
+
+                case KDBUS_ITEM_PAYLOAD_OFF: {
                         size_t begin_body;
 
                         begin_body = BUS_MESSAGE_BODY_BEGIN(m);
@@ -534,20 +750,27 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                                         goto fail;
                                 }
 
+                                /* A -1 offset is NUL padding. */
+                                part->is_zero = d->vec.offset == ~0ULL;
+
                                 if (idx >= begin_body) {
-                                        part->data = UINT64_TO_PTR(d->vec.address);
+                                        if (!part->is_zero)
+                                                part->data = (uint8_t *)k + d->vec.offset;
                                         part->size = d->vec.size;
                                 } else {
-                                        part->data = d->vec.address != 0 ? (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx) : NULL;
+                                        if (!part->is_zero)
+                                                part->data = (uint8_t *)k + d->vec.offset + (begin_body - idx);
                                         part->size = d->vec.size - (begin_body - idx);
                                 }
 
-                                part->is_zero = d->vec.address == 0;
                                 part->sealed = true;
                         }
 
                         idx += d->vec.size;
-                } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
+                        break;
+                }
+
+                case KDBUS_ITEM_PAYLOAD_MEMFD: {
                         struct bus_body_part *part;
 
                         if (idx < BUS_MESSAGE_BODY_BEGIN(m)) {
@@ -566,70 +789,111 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                         part->sealed = true;
 
                         idx += d->memfd.size;
+                        break;
+                }
+
+                case KDBUS_ITEM_CREDS:
+                        m->creds.pid_starttime = d->creds.starttime / NSEC_PER_USEC;
+                        m->creds.uid = d->creds.uid;
+                        m->creds.gid = d->creds.gid;
+                        m->creds.pid = d->creds.pid;
+                        m->creds.tid = d->creds.tid;
+                        m->creds.mask |= (SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID|SD_BUS_CREDS_PID_STARTTIME|SD_BUS_CREDS_TID) & bus->creds_mask;
+                        break;
 
-                } else if (d->type == KDBUS_MSG_SRC_CREDS) {
-                        m->pid_starttime = d->creds.starttime / NSEC_PER_USEC;
-                        m->uid = d->creds.uid;
-                        m->gid = d->creds.gid;
-                        m->pid = d->creds.pid;
-                        m->tid = d->creds.tid;
-                        m->uid_valid = m->gid_valid = true;
-                } else if (d->type == KDBUS_MSG_TIMESTAMP) {
+                case KDBUS_ITEM_TIMESTAMP:
                         m->realtime = d->timestamp.realtime_ns / NSEC_PER_USEC;
                         m->monotonic = d->timestamp.monotonic_ns / NSEC_PER_USEC;
-                } else if (d->type == KDBUS_MSG_SRC_PID_COMM)
-                        m->comm = d->str;
-                else if (d->type == KDBUS_MSG_SRC_TID_COMM)
-                        m->tid_comm = d->str;
-                else if (d->type == KDBUS_MSG_SRC_EXE)
-                        m->exe = d->str;
-                else if (d->type == KDBUS_MSG_SRC_CMDLINE) {
-                        m->cmdline = d->str;
-                        m->cmdline_length = l;
-                } else if (d->type == KDBUS_MSG_SRC_CGROUP)
-                        m->cgroup = d->str;
-                else if (d->type == KDBUS_MSG_SRC_AUDIT)
-                        m->audit = &d->audit;
-                else if (d->type == KDBUS_MSG_SRC_CAPS) {
-                        m->capability = d->data;
-                        m->capability_size = l;
-                } else if (d->type == KDBUS_MSG_DST_NAME)
+                        break;
+
+                case KDBUS_ITEM_PID_COMM:
+                        m->creds.comm = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_COMM & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_TID_COMM:
+                        m->creds.tid_comm = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_TID_COMM & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_EXE:
+                        m->creds.exe = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_EXE & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_CMDLINE:
+                        m->creds.cmdline = d->str;
+                        m->creds.cmdline_size = l;
+                        m->creds.mask |= SD_BUS_CREDS_CMDLINE & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_CGROUP:
+                        m->creds.cgroup = d->str;
+                        m->creds.mask |= (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID) & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_AUDIT:
+                        m->creds.audit_session_id = d->audit.sessionid;
+                        m->creds.audit_login_uid = d->audit.loginuid;
+                        m->creds.mask |= (SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID) & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_CAPS:
+                        m->creds.capability = d->data;
+                        m->creds.capability_size = l;
+                        m->creds.mask |= (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS) & bus->creds_mask;
+                        break;
+
+                case KDBUS_ITEM_DST_NAME:
                         destination = d->str;
-                else if (d->type != KDBUS_MSG_FDS &&
-                           d->type != KDBUS_MSG_SRC_SECLABEL)
+                        break;
+
+                case KDBUS_ITEM_NAME:
+                        r = strv_extend(&m->creds.well_known_names, d->name.name);
+                        if (r < 0)
+                                goto fail;
+                        break;
+
+                case KDBUS_ITEM_FDS:
+                case KDBUS_ITEM_SECLABEL:
+                        break;
+
+                default:
                         log_debug("Got unknown field from kernel %llu", d->type);
+                }
         }
 
         r = bus_message_parse_fields(m);
         if (r < 0)
                 goto fail;
 
+        /* Override information from the user header with data from the kernel */
         if (k->src_id == KDBUS_SRC_ID_KERNEL)
-                m->sender = "org.freedesktop.DBus";
+                m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus";
         else {
                 snprintf(m->sender_buffer, sizeof(m->sender_buffer), ":1.%llu", (unsigned long long) k->src_id);
-                m->sender = m->sender_buffer;
+                m->sender = m->creds.unique_name = m->sender_buffer;
         }
 
-        if (!m->destination) {
-                if (destination)
-                        m->destination = destination;
-                else if (k->dst_id != KDBUS_DST_ID_WELL_KNOWN_NAME &&
-                         k->dst_id != KDBUS_DST_ID_BROADCAST) {
-                        snprintf(m->destination_buffer, sizeof(m->destination_buffer), ":1.%llu", (unsigned long long) k->dst_id);
-                        m->destination = m->destination_buffer;
-                }
+        if (destination)
+                m->destination = destination;
+        else if (k->dst_id == KDBUS_DST_ID_BROADCAST)
+                m->destination = NULL;
+        else if (k->dst_id == KDBUS_DST_ID_NAME)
+                m->destination = bus->unique_name; /* fill in unique name if the well-known name is missing */
+        else {
+                snprintf(m->destination_buffer, sizeof(m->destination_buffer), ":1.%llu", (unsigned long long) k->dst_id);
+                m->destination = m->destination_buffer;
         }
 
         /* We take possession of the kmsg struct now */
         m->kdbus = k;
-        m->bus = sd_bus_ref(bus);
         m->release_kdbus = true;
         m->free_fds = true;
-
         fds = NULL;
 
-        *ret = m;
+        bus->rqueue[bus->rqueue_size++] = m;
+
         return 1;
 
 fail:
@@ -648,34 +912,201 @@ fail:
         return r;
 }
 
-int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) {
+int bus_kernel_read_message(sd_bus *bus) {
         struct kdbus_msg *k;
+        uint64_t off;
         int r;
 
         assert(bus);
-        assert(m);
 
-        r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &k);
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &off);
         if (r < 0) {
                 if (errno == EAGAIN)
                         return 0;
 
                 return -errno;
         }
+        k = (struct kdbus_msg *)((uint8_t *)bus->kdbus_buffer + off);
+
+        if (k->payload_type == KDBUS_PAYLOAD_DBUS) {
+                r = bus_kernel_make_message(bus, k);
+
+                /* Anybody can send us invalid messages, let's just drop them. */
+                if (r == -EBADMSG || r == -EPROTOTYPE) {
+                        log_debug("Ignoring invalid message: %s", strerror(-r));
+                        r = 0;
+                }
+
+        } else if (k->payload_type == KDBUS_PAYLOAD_KERNEL)
+                r = bus_kernel_translate_message(bus, k);
+        else
+                r = 0;
 
-        r = bus_kernel_make_message(bus, k, m);
         if (r <= 0)
                 close_kdbus_msg(bus, k);
 
         return r < 0 ? r : 1;
 }
 
-int bus_kernel_create(const char *name, char **s) {
-        struct kdbus_cmd_bus_make *make;
-        struct kdbus_item *n, *cg;
-        size_t l;
+int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *mapped, size_t *allocated) {
+        struct memfd_cache *c;
+        int fd;
+
+        assert(address);
+        assert(mapped);
+        assert(allocated);
+
+        if (!bus || !bus->is_kernel)
+                return -ENOTSUP;
+
+        assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) >= 0);
+
+        if (bus->n_memfd_cache <= 0) {
+                int r;
+
+                assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);
+
+                r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, &fd);
+                if (r < 0)
+                        return -errno;
+
+                *address = NULL;
+                *mapped = 0;
+                *allocated = 0;
+                return fd;
+        }
+
+        c = &bus->memfd_cache[--bus->n_memfd_cache];
+
+        assert(c->fd >= 0);
+        assert(c->mapped == 0 || c->address);
+
+        *address = c->address;
+        *mapped = c->mapped;
+        *allocated = c->allocated;
+        fd = c->fd;
+
+        assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);
+
+        return fd;
+}
+
+static void close_and_munmap(int fd, void *address, size_t size) {
+        if (size > 0)
+                assert_se(munmap(address, PAGE_ALIGN(size)) >= 0);
+
+        close_nointr_nofail(fd);
+}
+
+void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t mapped, size_t allocated) {
+        struct memfd_cache *c;
+        uint64_t max_mapped = PAGE_ALIGN(MEMFD_CACHE_ITEM_SIZE_MAX);
+
+        assert(fd >= 0);
+        assert(mapped == 0 || address);
+
+        if (!bus || !bus->is_kernel) {
+                close_and_munmap(fd, address, mapped);
+                return;
+        }
+
+        assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) >= 0);
+
+        if (bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
+                assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);
+
+                close_and_munmap(fd, address, mapped);
+                return;
+        }
+
+        c = &bus->memfd_cache[bus->n_memfd_cache++];
+        c->fd = fd;
+        c->address = address;
+
+        /* If overly long, let's return a bit to the OS */
+        if (mapped > max_mapped) {
+                assert_se(ioctl(fd, KDBUS_CMD_MEMFD_SIZE_SET, &max_mapped) >= 0);
+                assert_se(munmap((uint8_t*) address + max_mapped, PAGE_ALIGN(mapped - max_mapped)) >= 0);
+                c->mapped = c->allocated = max_mapped;
+        } else {
+                c->mapped = mapped;
+                c->allocated = allocated;
+        }
+
+        assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);
+}
+
+void bus_kernel_flush_memfd(sd_bus *b) {
+        unsigned i;
+
+        assert(b);
+
+        for (i = 0; i < b->n_memfd_cache; i++)
+                close_and_munmap(b->memfd_cache[i].fd, b->memfd_cache[i].address, b->memfd_cache[i].mapped);
+}
+
+int kdbus_translate_request_name_flags(uint64_t flags, uint64_t *kdbus_flags) {
+        uint64_t f = 0;
+
+        assert(kdbus_flags);
+
+        if (flags & SD_BUS_NAME_ALLOW_REPLACEMENT)
+                f |= KDBUS_NAME_ALLOW_REPLACEMENT;
+
+        if (flags & SD_BUS_NAME_REPLACE_EXISTING)
+                f |= KDBUS_NAME_REPLACE_EXISTING;
+
+        if (flags & SD_BUS_NAME_QUEUE)
+                f |= KDBUS_NAME_QUEUE;
+
+        *kdbus_flags = f;
+        return 0;
+}
+
+int kdbus_translate_attach_flags(uint64_t mask, uint64_t *kdbus_mask) {
+        uint64_t m = 0;
+
+        assert(kdbus_mask);
+
+        if (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID|SD_BUS_CREDS_PID_STARTTIME|SD_BUS_CREDS_TID))
+                m |= KDBUS_ATTACH_CREDS;
+
+        if (mask & (SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM))
+                m |= KDBUS_ATTACH_COMM;
+
+        if (mask & SD_BUS_CREDS_EXE)
+                m |= KDBUS_ATTACH_EXE;
+
+        if (mask & SD_BUS_CREDS_CMDLINE)
+                m |= KDBUS_ATTACH_CMDLINE;
+
+        if (mask & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID))
+                m |= KDBUS_ATTACH_CGROUP;
+
+        if (mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS))
+                m |= KDBUS_ATTACH_CAPS;
+
+        if (mask & SD_BUS_CREDS_SELINUX_CONTEXT)
+                m |= KDBUS_ATTACH_SECLABEL;
+
+        if (mask & (SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID))
+                m |= KDBUS_ATTACH_AUDIT;
+
+        if (mask & SD_BUS_CREDS_WELL_KNOWN_NAMES)
+                m |= KDBUS_ATTACH_NAMES;
+
+        *kdbus_mask = m;
+        return 0;
+}
+
+int bus_kernel_create_bus(const char *name, char **s) {
+        struct kdbus_cmd_make *make;
+        struct kdbus_item *n;
         int fd;
-        char *p;
 
         assert(name);
         assert(s);
@@ -684,115 +1115,197 @@ int bus_kernel_create(const char *name, char **s) {
         if (fd < 0)
                 return -errno;
 
-        l = strlen(name);
-        make = alloca0(offsetof(struct kdbus_cmd_bus_make, items) +
-                       KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t) +
-                       KDBUS_ITEM_HEADER_SIZE + DECIMAL_STR_MAX(uid_t) + 1 + l + 1);
+        make = alloca0(ALIGN8(offsetof(struct kdbus_cmd_make, items) +
+                              offsetof(struct kdbus_item, data64) + sizeof(uint64_t) +
+                              offsetof(struct kdbus_item, str) +
+                              DECIMAL_STR_MAX(uid_t) + 1 + strlen(name) + 1));
+
+        make->size = offsetof(struct kdbus_cmd_make, items);
 
-        cg = make->items;
-        cg->type = KDBUS_MAKE_CGROUP;
-        cg->data64[0] = 1;
-        cg->size = KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t);
+        n = make->items;
+        n->size = offsetof(struct kdbus_item, data64) + sizeof(uint64_t);
+        n->type = KDBUS_ITEM_BLOOM_SIZE;
+        n->data64[0] = BLOOM_SIZE;
+        assert_cc(BLOOM_SIZE % 8 == 0);
+        make->size += ALIGN8(n->size);
 
-        n = KDBUS_ITEM_NEXT(cg);
-        n->type = KDBUS_MAKE_NAME;
+        n = KDBUS_ITEM_NEXT(n);
         sprintf(n->str, "%lu-%s", (unsigned long) getuid(), name);
-        n->size = KDBUS_ITEM_HEADER_SIZE + strlen(n->str) + 1;
+        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
+        n->type = KDBUS_ITEM_MAKE_NAME;
+        make->size += ALIGN8(n->size);
 
-        make->size = offsetof(struct kdbus_cmd_bus_make, items) + cg->size + n->size;
         make->flags = KDBUS_MAKE_POLICY_OPEN;
-        make->bus_flags = 0;
-        make->bloom_size = BLOOM_SIZE;
-        assert_cc(BLOOM_SIZE % 8 == 0);
-
-        p = strjoin("/dev/kdbus/", n->str, "/bus", NULL);
-        if (!p)
-                return -ENOMEM;
 
         if (ioctl(fd, KDBUS_CMD_BUS_MAKE, make) < 0) {
                 close_nointr_nofail(fd);
-                free(p);
                 return -errno;
         }
 
-        if (s)
+        /* The higher 32bit of the flags field are considered
+         * 'incompatible flags'. Refuse them all for now. */
+        if (make->flags > 0xFFFFFFFFULL) {
+                close_nointr_nofail(fd);
+                return -ENOTSUP;
+        }
+
+        if (s) {
+                char *p;
+
+                p = strjoin("/dev/kdbus/", n->str, "/bus", NULL);
+                if (!p) {
+                        close_nointr_nofail(fd);
+                        return -ENOMEM;
+                }
+
                 *s = p;
+        }
 
         return fd;
 }
 
-int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
-        struct memfd_cache *c;
+int bus_kernel_create_starter(const char *bus, const char *name) {
+        struct kdbus_cmd_hello *hello;
+        struct kdbus_item *n;
+        char *p;
+        int fd;
 
-        assert(address);
-        assert(size);
+        assert(bus);
+        assert(name);
 
-        if (!bus || !bus->is_kernel)
-                return -ENOTSUP;
+        p = alloca(sizeof("/dev/kdbus/") - 1 + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + sizeof("/bus"));
+        sprintf(p, "/dev/kdbus/%lu-%s/bus", (unsigned long) getuid(), bus);
 
-        if (bus->n_memfd_cache <= 0) {
-                int fd, r;
+        fd = open(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
 
-                r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, &fd);
-                if (r < 0)
-                        return -errno;
+        hello = alloca0(ALIGN8(offsetof(struct kdbus_cmd_hello, items) +
+                               offsetof(struct kdbus_item, str) +
+                               strlen(name) + 1));
 
-                *address = NULL;
-                *size = 0;
-                return fd;
-        }
+        n = hello->items;
+        strcpy(n->str, name);
+        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
+        n->type = KDBUS_ITEM_NAME;
 
-        c = &bus->memfd_cache[-- bus->n_memfd_cache];
+        hello->size = ALIGN8(offsetof(struct kdbus_cmd_hello, items) + n->size);
+        hello->conn_flags = KDBUS_HELLO_ACTIVATOR;
+        hello->pool_size = KDBUS_POOL_SIZE;
 
-        assert(c->fd >= 0);
-        assert(c->size == 0 || c->address);
+        if (ioctl(fd, KDBUS_CMD_HELLO, hello) < 0) {
+                close_nointr_nofail(fd);
+                return -errno;
+        }
 
-        *address = c->address;
-        *size = c->size;
+        /* The higher 32bit of both flags fields are considered
+         * 'incompatible flags'. Refuse them all for now. */
+        if (hello->bus_flags > 0xFFFFFFFFULL ||
+            hello->conn_flags > 0xFFFFFFFFULL) {
+                close_nointr_nofail(fd);
+                return -ENOTSUP;
+        }
 
-        return c->fd;
+        if (hello->bloom_size != BLOOM_SIZE) {
+                close_nointr_nofail(fd);
+                return -ENOTSUP;
+        }
+
+        return fd;
 }
 
-void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
-        struct memfd_cache *c;
+int bus_kernel_create_namespace(const char *name, char **s) {
+        struct kdbus_cmd_make *make;
+        struct kdbus_item *n;
+        int fd;
 
-        assert(fd >= 0);
-        assert(size == 0 || address);
+        assert(name);
+        assert(s);
+
+        fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        make = alloca0(ALIGN8(offsetof(struct kdbus_cmd_make, items) +
+                              offsetof(struct kdbus_item, str) +
+                              strlen(name) + 1));
 
-        if (!bus || !bus->is_kernel ||
-            bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
+        n = make->items;
+        strcpy(n->str, name);
+        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
+        n->type = KDBUS_ITEM_MAKE_NAME;
 
-                if (size > 0)
-                        assert_se(munmap(address, PAGE_ALIGN(size)) == 0);
+        make->size = ALIGN8(offsetof(struct kdbus_cmd_make, items) + n->size);
+        make->flags = KDBUS_MAKE_POLICY_OPEN | KDBUS_MAKE_ACCESS_WORLD;
 
+        if (ioctl(fd, KDBUS_CMD_NS_MAKE, make) < 0) {
                 close_nointr_nofail(fd);
-                return;
+                return -errno;
         }
 
-        c = &bus->memfd_cache[bus->n_memfd_cache++];
-        c->fd = fd;
-        c->address = address;
+        /* The higher 32bit of the flags field are considered
+         * 'incompatible flags'. Refuse them all for now. */
+        if (make->flags > 0xFFFFFFFFULL) {
+                close_nointr_nofail(fd);
+                return -ENOTSUP;
+        }
 
-        /* If overly long, let's return a bit to the OS */
-        if (size > MEMFD_CACHE_ITEM_SIZE_MAX) {
-                uint64_t sz = MEMFD_CACHE_ITEM_SIZE_MAX;
+        if (s) {
+                char *p;
 
-                ioctl(bus->input_fd, KDBUS_CMD_MEMFD_SIZE_SET, &sz);
+                p = strappend("/dev/kdbus/ns/", name);
+                if (!p) {
+                        close_nointr_nofail(fd);
+                        return -ENOMEM;
+                }
 
-                c->size = MEMFD_CACHE_ITEM_SIZE_MAX;
-        } else
-                c->size = size;
+                *s = p;
+        }
+
+        return fd;
 }
 
-void bus_kernel_flush_memfd(sd_bus *b) {
-        unsigned i;
+int bus_kernel_create_monitor(const char *bus) {
+        struct kdbus_cmd_hello *hello;
+        char *p;
+        int fd;
 
-        assert(b);
+        assert(bus);
+
+        p = alloca(sizeof("/dev/kdbus/") - 1 + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + sizeof("/bus"));
+        sprintf(p, "/dev/kdbus/%lu-%s/bus", (unsigned long) getuid(), bus);
+
+        fd = open(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
 
-        for (i = 0; i < b->n_memfd_cache; i++) {
-                if (b->memfd_cache[i].size > 0)
-                        assert_se(munmap(b->memfd_cache[i].address, PAGE_ALIGN(b->memfd_cache[i].size)) == 0);
+        hello = alloca0(sizeof(struct kdbus_cmd_hello));
+        hello->size = sizeof(struct kdbus_cmd_hello);
+        hello->conn_flags = KDBUS_HELLO_ACTIVATOR;
+        hello->pool_size = KDBUS_POOL_SIZE;
 
-                close_nointr_nofail(b->memfd_cache[i].fd);
+        if (ioctl(fd, KDBUS_CMD_HELLO, hello) < 0) {
+                close_nointr_nofail(fd);
+                return -errno;
         }
+
+        /* The higher 32bit of both flags fields are considered
+         * 'incompatible flags'. Refuse them all for now. */
+        if (hello->bus_flags > 0xFFFFFFFFULL ||
+            hello->conn_flags > 0xFFFFFFFFULL) {
+                close_nointr_nofail(fd);
+                return -ENOTSUP;
+        }
+
+        return fd;
+}
+
+int bus_kernel_try_close(sd_bus *bus) {
+        assert(bus);
+        assert(bus->is_kernel);
+
+        if (ioctl(bus->input_fd, KDBUS_CMD_BYEBYE) < 0)
+                return -errno;
+
+        return 0;
 }