chiark / gitweb /
bus: implement receiving side of memfd hookup
[elogind.git] / src / libsystemd-bus / bus-kernel.c
index 2b3f46a64ba18c968f7e6b8388c5be7804db0205..f7759b6fb498ea9f8c9926504124b86137139b80 100644 (file)
 #endif
 
 #include <fcntl.h>
+#include <malloc.h>
+#include <sys/mman.h>
 
 #include "util.h"
 
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-kernel.h"
+#include "bus-bloom.h"
 
-#define KDBUS_MSG_FOREACH_DATA(d, k)                                    \
-        for ((d) = (k)->data;                                           \
-             (uint8_t*) (d) < (uint8_t*) (k) + (k)->size;               \
-             (d) = (struct kdbus_msg_data*) ((uint8_t*) (d) + ALIGN8((d)->size)))
+#define KDBUS_ITEM_NEXT(item) \
+        (typeof(item))(((uint8_t *)item) + ALIGN8((item)->size))
+
+#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 r;
@@ -52,37 +63,149 @@ static int parse_unique_name(const char *s, uint64_t *id) {
         return 1;
 }
 
-static void append_payload_vec(struct kdbus_msg_data **d, const void *p, size_t sz) {
+static void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz) {
         assert(d);
-        assert(p);
         assert(sz > 0);
 
-        (*d)->size = offsetof(struct kdbus_msg_data, vec) + sizeof(struct kdbus_vec);
+        *d = ALIGN8_PTR(*d);
+
+        (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec);
         (*d)->type = KDBUS_MSG_PAYLOAD_VEC;
-        (*d)->vec.address = (uint64_t) p;
+        (*d)->vec.address = PTR_TO_UINT64(p);
         (*d)->vec.size = sz;
 
-        *d = (struct kdbus_msg_data*) ((uint8_t*) *d + ALIGN8((*d)->size));
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 }
 
-static void append_destination(struct kdbus_msg_data **d, const char *s, size_t length) {
+static void append_payload_memfd(struct kdbus_item **d, int memfd, size_t sz) {
         assert(d);
+        assert(memfd >= 0);
+        assert(sz > 0);
+
+        *d = ALIGN8_PTR(*d);
+        (*d)->size = offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd);
+        (*d)->type = KDBUS_MSG_PAYLOAD_MEMFD;
+        (*d)->memfd.fd = memfd;
+        (*d)->memfd.size = sz;
+
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
+}
+
+static void append_destination(struct kdbus_item **d, const char *s, size_t length) {
         assert(d);
+        assert(s);
+
+        *d = ALIGN8_PTR(*d);
 
-        (*d)->size = offsetof(struct kdbus_msg_data, data) + length + 1;
+        (*d)->size = offsetof(struct kdbus_item, str) + length + 1;
         (*d)->type = KDBUS_MSG_DST_NAME;
-        memcpy((*d)->data, s, length + 1);
+        memcpy((*d)->str, s, length + 1);
 
-        *d = (struct kdbus_msg_data*) ((uint8_t*) *d + ALIGN8((*d)->size));
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 }
 
-static int bus_message_setup_kmsg(sd_bus_message *m) {
-        struct kdbus_msg_data *d;
+static void* append_bloom(struct kdbus_item **d, size_t length) {
+        void *r;
+
+        assert(d);
+
+        *d = ALIGN8_PTR(*d);
+
+        (*d)->size = offsetof(struct kdbus_item, data) + length;
+        (*d)->type = KDBUS_MSG_BLOOM;
+        r = (*d)->data;
+
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
+
+        return r;
+}
+
+static void append_fds(struct kdbus_item **d, const int fds[], unsigned n_fds) {
+        assert(d);
+        assert(fds);
+        assert(n_fds > 0);
+
+        *d = ALIGN8_PTR(*d);
+        (*d)->size = offsetof(struct kdbus_item, fds) + sizeof(int) * n_fds;
+        (*d)->type = KDBUS_MSG_FDS;
+        memcpy((*d)->fds, fds, sizeof(int) * n_fds);
+
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
+}
+
+static int bus_message_setup_bloom(sd_bus_message *m, void *bloom) {
+        unsigned i;
+        int r;
+
+        assert(m);
+        assert(bloom);
+
+        memset(bloom, 0, BLOOM_SIZE);
+
+        bloom_add_pair(bloom, "message-type", bus_message_type_to_string(m->header->type));
+
+        if (m->interface)
+                bloom_add_pair(bloom, "interface", m->interface);
+        if (m->member)
+                bloom_add_pair(bloom, "member", m->member);
+        if (m->path) {
+                bloom_add_pair(bloom, "path", m->path);
+                bloom_add_prefixes(bloom, "path-slash-prefix", m->path, '/');
+        }
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < 64; i++) {
+                char type;
+                const char *t;
+                char buf[sizeof("arg")-1 + 2 + sizeof("-slash-prefix")];
+                char *e;
+
+                r = sd_bus_message_peek_type(m, &type, NULL);
+                if (r < 0)
+                        return r;
+
+                if (type != SD_BUS_TYPE_STRING &&
+                    type != SD_BUS_TYPE_OBJECT_PATH &&
+                    type != SD_BUS_TYPE_SIGNATURE)
+                        break;
+
+                r = sd_bus_message_read_basic(m, type, &t);
+                if (r < 0)
+                        return r;
+
+                e = stpcpy(buf, "arg");
+                if (i < 10)
+                        *(e++) = '0' + i;
+                else {
+                        *(e++) = '0' + (i / 10);
+                        *(e++) = '0' + (i % 10);
+                }
+
+                *e = 0;
+                bloom_add_pair(bloom, buf, t);
+
+                strcpy(e, "-dot-prefix");
+                bloom_add_prefixes(bloom, buf, t, '.');
+                strcpy(e, "-slash-prefix");
+                bloom_add_prefixes(bloom, buf, t, '/');
+        }
+
+        return 0;
+}
+
+static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
+        struct bus_body_part *part;
+        struct kdbus_item *d;
         bool well_known;
         uint64_t unique;
         size_t sz, dl;
+        unsigned i;
         int r;
 
+        assert(b);
         assert(m);
         assert(m->sealed);
 
@@ -98,51 +221,87 @@ static int bus_message_setup_kmsg(sd_bus_message *m) {
         } else
                 well_known = false;
 
-        sz = offsetof(struct kdbus_msg, data);
+        sz = offsetof(struct kdbus_msg, items);
 
-        /* Add in fixed header, fields header, fields header padding and payload */
-        sz += 4 * ALIGN8(offsetof(struct kdbus_msg_data, vec) + sizeof(struct kdbus_vec));
+        assert_cc(ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)) ==
+                  ALIGN8(offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd)));
+
+        /* Add in fixed header, fields header and payload */
+        sz += (1 + m->n_body_parts) *
+                ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec));
+
+        /* Add space for bloom filter */
+        sz += ALIGN8(offsetof(struct kdbus_item, data) + BLOOM_SIZE);
 
         /* Add in well-known destination header */
         if (well_known) {
                 dl = strlen(m->destination);
-                sz += ALIGN8(offsetof(struct kdbus_msg, data) + dl + 1);
+                sz += ALIGN8(offsetof(struct kdbus_item, str) + dl + 1);
         }
 
-        m->kdbus = malloc0(sz);
+        /* Add space for unix fds */
+        if (m->n_fds > 0)
+                sz += ALIGN8(offsetof(struct kdbus_item, fds) + sizeof(int)*m->n_fds);
+
+        m->kdbus = memalign(8, sz);
         if (!m->kdbus)
                 return -ENOMEM;
 
+        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->kdbus->dst_id =
                 well_known ? 0 :
-                m->destination ? unique : (uint64_t) -1;
+                m->destination ? unique : KDBUS_DST_ID_BROADCAST;
         m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS1;
         m->kdbus->cookie = m->header->serial;
 
         m->kdbus->timeout_ns = m->timeout * NSEC_PER_USEC;
 
-        d = m->kdbus->data;
+        d = m->kdbus->items;
 
         if (well_known)
                 append_destination(&d, m->destination, dl);
 
-        append_payload_vec(&d, m->header, sizeof(*m->header));
+        append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m));
+
+        MESSAGE_FOREACH_PART(part, i, m) {
+                if (part->is_zero) {
+                        append_payload_vec(&d, NULL, part->size);
+                        continue;
+                }
 
-        if (m->fields) {
-                append_payload_vec(&d, m->fields, m->header->fields_size);
+                if (part->memfd >= 0 && part->sealed) {
+                        bus_body_part_unmap(part);
 
-                if (m->header->fields_size % 8 != 0) {
-                        static const uint8_t padding[7] = {};
+                        if (!part->data) {
+                                append_payload_memfd(&d, part->memfd, part->size);
+                                continue;
+                        }
+                }
 
-                        append_payload_vec(&d, padding, 8 - (m->header->fields_size % 8));
+                if (part->memfd >= 0) {
+                        r = bus_body_part_map(part);
+                        if (r < 0)
+                                goto fail;
                 }
+
+                append_payload_vec(&d, part->data, part->size);
         }
 
-        if (m->body)
-                append_payload_vec(&d, m->body, m->header->body_size);
+        if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) {
+                void *p;
+
+                p = append_bloom(&d, BLOOM_SIZE);
+                r = bus_message_setup_bloom(m, p);
+                if (r < 0)
+                        goto fail;
+        }
+
+        if (m->n_fds > 0)
+                append_fds(&d, m->fds, m->n_fds);
 
         m->kdbus->size = (uint8_t*) d - (uint8_t*) m->kdbus;
         assert(m->kdbus->size <= sz);
@@ -150,10 +309,20 @@ static int bus_message_setup_kmsg(sd_bus_message *m) {
         m->free_kdbus = true;
 
         return 0;
+
+fail:
+        free(m->kdbus);
+        m->kdbus = NULL;
+        return r;
 }
 
 int bus_kernel_take_fd(sd_bus *b) {
-        struct kdbus_cmd_hello hello = {};
+        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;
+
         int r;
 
         assert(b);
@@ -161,15 +330,49 @@ int bus_kernel_take_fd(sd_bus *b) {
         if (b->is_server)
                 return -EINVAL;
 
-        r = ioctl(b->input_fd, KDBUS_CMD_HELLO, &hello);
+        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;
+                }
+        }
+
+        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->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;
+
+        r = ioctl(b->input_fd, KDBUS_CMD_HELLO, hello);
         if (r < 0)
                 return -errno;
 
-        if (asprintf(&b->unique_name, ":1.%llu", (unsigned long long) hello.id) < 0)
+        /* 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)
+                return -ENOTSUP;
+
+        if (hello->bloom_size != BLOOM_SIZE)
+                return -ENOTSUP;
+
+        if (asprintf(&b->unique_name, ":1.%llu", (unsigned long long) hello->id) < 0)
                 return -ENOMEM;
 
         b->is_kernel = true;
         b->bus_client = true;
+        b->can_fds = true;
 
         r = bus_start_running(b);
         if (r < 0)
@@ -203,7 +406,7 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) {
         assert(m);
         assert(bus->state == BUS_RUNNING);
 
-        r = bus_message_setup_kmsg(m);
+        r = bus_message_setup_kmsg(bus, m);
         if (r < 0)
                 return r;
 
@@ -211,30 +414,34 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) {
         if (r < 0)
                 return errno == EAGAIN ? 0 : -errno;
 
-        return 0;
+        return 1;
 }
 
-static void close_kdbus_msg(struct kdbus_msg *k) {
-        struct kdbus_msg_data *d;
+static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
+        struct kdbus_item *d;
 
-        KDBUS_MSG_FOREACH_DATA(d, k) {
+        assert(bus);
+        assert(k);
 
-                if (d->type != KDBUS_MSG_UNIX_FDS)
-                        continue;
+        ioctl(bus->input_fd, KDBUS_CMD_MSG_RELEASE, k);
 
-                close_many(d->fds, (d->size - offsetof(struct kdbus_msg_data, fds)) / sizeof(int));
+        KDBUS_ITEM_FOREACH(d, k) {
+
+                if (d->type == KDBUS_MSG_FDS)
+                        close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
+                else if (d->type == KDBUS_MSG_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) {
         sd_bus_message *m = NULL;
-        struct kdbus_msg_data *d;
-        unsigned n_payload = 0, n_fds = 0;
+        struct kdbus_item *d;
+        unsigned n_fds = 0;
         _cleanup_free_ int *fds = NULL;
         struct bus_header *h = NULL;
         size_t total, n_bytes = 0, idx = 0;
-        struct kdbus_creds *creds = NULL;
-        uint64_t nsec = 0;
+        const char *destination = NULL, *seclabel = NULL;
         int r;
 
         assert(bus);
@@ -244,24 +451,30 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
         if (k->payload_type != KDBUS_PAYLOAD_DBUS1)
                 return 0;
 
-        KDBUS_MSG_FOREACH_DATA(d, k) {
+        KDBUS_ITEM_FOREACH(d, k) {
                 size_t l;
 
-                l = d->size - offsetof(struct kdbus_msg_data, data);
+                l = d->size - offsetof(struct kdbus_item, data);
 
-                if (d->type == KDBUS_MSG_PAYLOAD) {
+                if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
 
                         if (!h) {
-                                if (l < sizeof(struct bus_header))
-                                        return -EBADMSG;
+                                h = UINT64_TO_PTR(d->vec.address);
 
-                                h = (struct bus_header*) d->data;
+                                if (!bus_header_is_complete(h, d->vec.size))
+                                        return -EBADMSG;
                         }
 
-                        n_payload++;
-                        n_bytes += l;
+                        n_bytes += d->vec.size;
+
+                } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
+
+                        if (!h)
+                                return -EBADMSG;
 
-                } else if (d->type == KDBUS_MSG_UNIX_FDS) {
+                        n_bytes += d->memfd.size;
+
+                } else if (d->type == KDBUS_MSG_FDS) {
                         int *f;
                         unsigned j;
 
@@ -271,128 +484,187 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                                 return -ENOMEM;
 
                         fds = f;
-                        memcpy(fds + n_fds, d->fds, j);
+                        memcpy(fds + n_fds, d->fds, sizeof(int) * j);
                         n_fds += j;
 
-                } else if (d->type == KDBUS_MSG_SRC_CREDS)
-                        creds = &d->creds;
-                else if (d->type == KDBUS_MSG_TIMESTAMP)
-                        nsec = d->ts_ns;
+                } else if (d->type == KDBUS_MSG_SRC_SECLABEL)
+                        seclabel = d->str;
         }
 
         if (!h)
                 return -EBADMSG;
 
-        r = bus_header_size(h, &total);
+        r = bus_header_message_size(h, &total);
         if (r < 0)
                 return r;
 
         if (n_bytes != total)
                 return -EBADMSG;
 
-        r = bus_message_from_header(h, sizeof(struct bus_header), fds, n_fds, NULL, NULL, 0, &m);
+        r = bus_message_from_header(h, sizeof(struct bus_header), fds, n_fds, NULL, seclabel, 0, &m);
         if (r < 0)
                 return r;
 
-        KDBUS_MSG_FOREACH_DATA(d, k) {
+        KDBUS_ITEM_FOREACH(d, k) {
                 size_t l;
 
-                if (d->type != KDBUS_MSG_PAYLOAD)
-                        continue;
+                l = d->size - offsetof(struct kdbus_item, data);
 
-                l = d->size - offsetof(struct kdbus_msg_data, data);
-                if (idx == sizeof(struct bus_header) &&
-                    l == BUS_MESSAGE_FIELDS_SIZE(m))
-                        m->fields = d->data;
-                else if (idx == sizeof(struct bus_header) + ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m)) &&
-                         l == BUS_MESSAGE_BODY_SIZE(m))
-                        m->body = d->data;
-                else if (!(idx == 0 && l == sizeof(struct bus_header)) &&
-                         !(idx == sizeof(struct bus_header) + BUS_MESSAGE_FIELDS_SIZE(m))) {
-                        sd_bus_message_unref(m);
-                        return -EBADMSG;
-                }
+                if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
+                        size_t begin_body;
 
-                idx += l;
-        }
+                        begin_body = BUS_MESSAGE_BODY_BEGIN(m);
 
-        if (creds) {
-                m->pid_starttime = creds->starttime / NSEC_PER_USEC;
-                m->uid = creds->uid;
-                m->gid = creds->gid;
-                m->pid = creds->pid;
-                m->tid = creds->tid;
-                m->uid_valid = m->gid_valid = true;
-        }
+                        if (idx + d->vec.size > begin_body) {
+                                struct bus_body_part *part;
+
+                                /* Contains body material */
 
-        m->timestamp = nsec / NSEC_PER_USEC;
+                                part = message_append_part(m);
+                                if (!part) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                if (idx >= begin_body) {
+                                        part->data = UINT64_TO_PTR(d->vec.address);
+                                        part->size = d->vec.size;
+                                } else {
+                                        part->data = d->vec.address != 0 ? (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx) : NULL;
+                                        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) {
+                        struct bus_body_part *part;
+
+                        if (idx < BUS_MESSAGE_BODY_BEGIN(m)) {
+                                r = -EBADMSG;
+                                goto fail;
+                        }
+
+                        part = message_append_part(m);
+                        if (!part) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        part->memfd = d->memfd.fd;
+                        part->size = d->memfd.size;
+                        part->sealed = true;
+
+                        idx += d->memfd.size;
+
+                } 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) {
+                        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)
+                        destination = d->str;
+                else if (d->type != KDBUS_MSG_FDS &&
+                           d->type != KDBUS_MSG_SRC_SECLABEL)
+                        log_debug("Got unknown field from kernel %llu", d->type);
+        }
 
         r = bus_message_parse_fields(m);
-        if (r < 0) {
-                sd_bus_message_unref(m);
-                return r;
+        if (r < 0)
+                goto fail;
+
+        if (k->src_id == KDBUS_SRC_ID_KERNEL)
+                m->sender = "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;
+        }
+
+        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;
+                }
         }
 
         /* We take possession of the kmsg struct now */
         m->kdbus = k;
-        m->free_kdbus = true;
+        m->bus = sd_bus_ref(bus);
+        m->release_kdbus = true;
         m->free_fds = true;
 
         fds = NULL;
 
         *ret = m;
         return 1;
+
+fail:
+        if (m) {
+                struct bus_body_part *part;
+                unsigned i;
+
+                /* Make sure the memfds are not freed twice */
+                MESSAGE_FOREACH_PART(part, i, m)
+                        if (part->memfd >= 0)
+                                part->memfd = -1;
+
+                sd_bus_message_unref(m);
+        }
+
+        return r;
 }
 
 int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) {
         struct kdbus_msg *k;
-        size_t sz = 1024;
         int r;
 
         assert(bus);
         assert(m);
 
-        for (;;) {
-                void *q;
-
-                q = realloc(bus->rbuffer, sz);
-                if (!q)
-                        return -errno;
-
-                k = bus->rbuffer = q;
-                k->size = sz;
-
-                /* Let's tell valgrind that there's really no need to
-                 * initialize this fully. This should be removed again
-                 * when valgrind learned the kdbus ioctls natively. */
-#ifdef HAVE_VALGRIND_MEMCHECK_H
-                VALGRIND_MAKE_MEM_DEFINED(k, sz);
-#endif
-
-                r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, bus->rbuffer);
-                if (r >= 0)
-                        break;
-
+        r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &k);
+        if (r < 0) {
                 if (errno == EAGAIN)
                         return 0;
 
-                if (errno != ENOBUFS)
-                        return -errno;
-
-                sz *= 2;
+                return -errno;
         }
 
         r = bus_kernel_make_message(bus, k, m);
-        if (r > 0)
-                bus->rbuffer = NULL;
-        else
-                close_kdbus_msg(k);
+        if (r <= 0)
+                close_kdbus_msg(bus, k);
 
-        return r;
+        return r < 0 ? r : 1;
 }
 
 int bus_kernel_create(const char *name, char **s) {
-        struct kdbus_cmd_fname *fname;
+        struct kdbus_cmd_bus_make *make;
+        struct kdbus_item *n, *cg;
         size_t l;
         int fd;
         char *p;
@@ -405,17 +677,31 @@ int bus_kernel_create(const char *name, char **s) {
                 return -errno;
 
         l = strlen(name);
-        fname = alloca(offsetof(struct kdbus_cmd_fname, name) + DECIMAL_STR_MAX(uid_t) + 1 + l + 1);
-        sprintf(fname->name, "%lu-%s", (unsigned long) getuid(), name);
-        fname->size = offsetof(struct kdbus_cmd_fname, name) + strlen(fname->name) + 1;
-        fname->kernel_flags = KDBUS_CMD_FNAME_ACCESS_WORLD | KDBUS_CMD_FNAME_POLICY_NONE;
-        fname->user_flags = 0;
-
-        p = strjoin("/dev/kdbus/", fname->name, "/bus", NULL);
+        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);
+
+        cg = make->items;
+        cg->type = KDBUS_MAKE_CGROUP;
+        cg->data64[0] = 1;
+        cg->size = KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t);
+
+        n = KDBUS_ITEM_NEXT(cg);
+        n->type = KDBUS_MAKE_NAME;
+        sprintf(n->str, "%lu-%s", (unsigned long) getuid(), name);
+        n->size = KDBUS_ITEM_HEADER_SIZE + strlen(n->str) + 1;
+
+        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, fname) < 0) {
+        if (ioctl(fd, KDBUS_CMD_BUS_MAKE, make) < 0) {
                 close_nointr_nofail(fd);
                 free(p);
                 return -errno;
@@ -426,3 +712,79 @@ int bus_kernel_create(const char *name, char **s) {
 
         return fd;
 }
+
+int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
+        struct memfd_cache *c;
+
+        assert(address);
+        assert(size);
+
+        if (!bus || !bus->is_kernel)
+                return -ENOTSUP;
+
+        if (bus->n_memfd_cache <= 0) {
+                int fd, r;
+
+                r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, &fd);
+                if (r < 0)
+                        return -errno;
+
+                *address = NULL;
+                *size = 0;
+                return fd;
+        }
+
+        c = &bus->memfd_cache[-- bus->n_memfd_cache];
+
+        assert(c->fd >= 0);
+        assert(c->size == 0 || c->address);
+
+        *address = c->address;
+        *size = c->size;
+
+        return c->fd;
+}
+
+void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
+        struct memfd_cache *c;
+
+        assert(fd >= 0);
+        assert(size == 0 || address);
+
+        if (!bus || !bus->is_kernel ||
+            bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
+
+                if (size > 0)
+                        assert_se(munmap(address, PAGE_ALIGN(size)) == 0);
+
+                close_nointr_nofail(fd);
+                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 (size > MEMFD_CACHE_ITEM_SIZE_MAX) {
+                uint64_t sz = MEMFD_CACHE_ITEM_SIZE_MAX;
+
+                ioctl(bus->input_fd, KDBUS_CMD_MEMFD_SIZE_SET, &sz);
+
+                c->size = MEMFD_CACHE_ITEM_SIZE_MAX;
+        } else
+                c->size = size;
+}
+
+void bus_kernel_flush_memfd(sd_bus *b) {
+        unsigned i;
+
+        assert(b);
+
+        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);
+
+                close_nointr_nofail(b->memfd_cache[i].fd);
+        }
+}