libsystemd/sd-bus/bus-kernel.c

	bus-kernel.c revision 03785ad0e51b061efb9f9b3f2e328685f9a866aa
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt/***
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  This file is part of systemd.
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  Copyright 2013 Lennart Poettering
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  systemd is free software; you can redistribute it and/or modify it
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  under the terms of the GNU Lesser General Public License as published by
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  the Free Software Foundation; either version 2.1 of the License, or
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  (at your option) any later version.
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  systemd is distributed in the hope that it will be useful, but
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  WITHOUT ANY WARRANTY; without even the implied warranty of
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  Lesser General Public License for more details.
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  You should have received a copy of the GNU Lesser General Public License
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt  along with systemd; If not, see <http://www.gnu.org/licenses/>.
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt***/
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#ifdef HAVE_VALGRIND_MEMCHECK_H
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <valgrind/memcheck.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#endif
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <fcntl.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <malloc.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <libgen.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <sys/mman.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include <sys/prctl.h>
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "util.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "strv.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-internal.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-message.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-kernel.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-bloom.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-util.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "bus-label.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#include "cgroup-util.h"
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt#define UNIQUE_NAME_MAX (3+DECIMAL_STR_MAX(uint64_t))
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flyktint bus_kernel_parse_unique_name(const char *s, uint64_t *id) {
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        int r;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        assert(s);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        assert(id);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        if (!startswith(s, ":1."))
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt                return 0;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        r = safe_atou64(s + 3, id);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        if (r < 0)
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt                return r;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        return 1;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt}
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flyktstatic void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz) {
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        assert(d);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        assert(sz > 0);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        *d = ALIGN8_PTR(*d);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        /* Note that p can be NULL, which encodes a region full of
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt         * zeroes, which is useful to optimize certain padding
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt         * conditions */
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        (*d)->type = KDBUS_ITEM_PAYLOAD_VEC;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        (*d)->vec.address = PTR_TO_UINT64(p);
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        (*d)->vec.size = sz;
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt
813e3a6ffcd094696001716480bbd68008cc54c8Patrik Flykt        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
}

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_ITEM_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_item, str) + length + 1;
        (*d)->type = KDBUS_ITEM_DST_NAME;
        memcpy((*d)->str, s, length + 1);

        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
}

static struct kdbus_bloom_filter *append_bloom(struct kdbus_item **d, size_t length) {
        struct kdbus_item *i;

        assert(d);

        i = ALIGN8_PTR(*d);

        i->size = offsetof(struct kdbus_item, bloom_filter) +
                  offsetof(struct kdbus_bloom_filter, data) +
                  length;
        i->type = KDBUS_ITEM_BLOOM_FILTER;

        *d = (struct kdbus_item *) ((uint8_t*) i + i->size);

        return &i->bloom_filter;
}

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_ITEM_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, struct kdbus_bloom_filter *bloom) {
        void *data;
        unsigned i;
        int r;

        assert(m);
        assert(bloom);

        data = bloom->data;
        memzero(data, m->bus->bloom_size);
        bloom->generation = 0;

        bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, "message-type", bus_message_type_to_string(m->header->type));

        if (m->interface)
                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, "interface", m->interface);
        if (m->member)
                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, "member", m->member);
        if (m->path) {
                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, "path", m->path);
                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, "path-slash-prefix", m->path);
                bloom_add_prefixes(data, m->bus->bloom_size, m->bus->bloom_n_hash, "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' + (char) i;
                else {
                        *(e++) = '0' + (char) (i / 10);
                        *(e++) = '0' + (char) (i % 10);
                }

                *e = 0;
                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, buf, t);

                strcpy(e, "-dot-prefix");
                bloom_add_prefixes(data, m->bus->bloom_size, m->bus->bloom_n_hash, buf, t, '.');
                strcpy(e, "-slash-prefix");
                bloom_add_prefixes(data, m->bus->bloom_size, m->bus->bloom_n_hash, 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);

        /* We put this together only once, if this message is reused
         * we reuse the earlier-built version */
        if (m->kdbus)
                return 0;

        if (m->destination) {
                r = bus_kernel_parse_unique_name(m->destination, &unique);
                if (r < 0)
                        return r;

                well_known = r == 0;
        } else
                well_known = false;

        sz = offsetof(struct kdbus_msg, items);

        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, bloom_filter) +
                     offsetof(struct kdbus_bloom_filter, data) +
                     m->bus->bloom_size);

        /* Add in well-known destination header */
        if (well_known) {
                dl = strlen(m->destination);
                sz += ALIGN8(offsetof(struct kdbus_item, str) + dl + 1);
        }

        /* 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) {
                r = -ENOMEM;
                goto fail;
        }

        m->free_kdbus = true;
        memzero(m->kdbus, sz);

        m->kdbus->flags =
                ((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_DBUS;
        m->kdbus->cookie = (uint64_t) m->header->serial;
        m->kdbus->priority = m->priority;

        if (m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) {
                m->kdbus->cookie_reply = m->reply_cookie;
        } else {
                struct timespec now;

                r = clock_gettime(CLOCK_MONOTONIC_COARSE, &now);
                if (r < 0) {
                        r = -errno;
                        goto fail;
                }

                m->kdbus->timeout_ns = now.tv_sec * NSEC_PER_SEC + now.tv_nsec +
                                       m->timeout * NSEC_PER_USEC;
        }

        d = m->kdbus->items;

        if (well_known)
                append_destination(&d, m->destination, dl);

        append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m));

        MESSAGE_FOREACH_PART(part, i, m) {
                if (part->is_zero) {
                        /* If this is padding then simply send a
                         * vector with a NULL data pointer which the
                         * kernel will just pass through. This is the
                         * most efficient way to encode zeroes */

                        append_payload_vec(&d, NULL, part->size);
                        continue;
                }

                if (part->memfd >= 0 && part->sealed && m->destination) {
                        /* Try to send a memfd, if the part is
                         * sealed and this is not a broadcast. Since we can only  */

                        append_payload_memfd(&d, part->memfd, part->size);
                        continue;
                }

                /* Otherwise, let's send a vector to the actual data.
                 * For that, we need to map it first. */
                r = bus_body_part_map(part);
                if (r < 0)
                        goto fail;

                append_payload_vec(&d, part->data, part->size);
        }

        if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) {
                struct kdbus_bloom_filter *bloom;

                bloom = append_bloom(&d, m->bus->bloom_size);
                r = bus_message_setup_bloom(m, bloom);
                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);

        return 0;

fail:
        m->poisoned = true;
        return r;
}

static void unset_memfds(struct sd_bus_message *m) {
        struct bus_body_part *part;
        unsigned i;

        assert(m);

        /* Make sure the memfds are not freed twice */
        MESSAGE_FOREACH_PART(part, i, m)
                if (part->memfd >= 0)
                        part->memfd = -1;
}

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;
        _cleanup_free_ int *fds = NULL;
        struct bus_header *h = NULL;
        size_t total, n_bytes = 0, idx = 0;
        const char *destination = NULL, *seclabel = NULL;
        int r;

        assert(bus);
        assert(k);
        assert(k->payload_type == KDBUS_PAYLOAD_DBUS);

        KDBUS_ITEM_FOREACH(d, k, items) {
                size_t l;

                l = d->size - offsetof(struct kdbus_item, data);

                switch (d->type) {

                case KDBUS_ITEM_PAYLOAD_OFF:
                        if (!h) {
                                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;

                case KDBUS_ITEM_PAYLOAD_MEMFD:
                        if (!h)
                                return -EBADMSG;

                        n_bytes += d->memfd.size;
                        break;

                case KDBUS_ITEM_FDS: {
                        int *f;
                        unsigned j;

                        j = l / sizeof(int);
                        f = realloc(fds, sizeof(int) * (n_fds + j));
                        if (!f)
                                return -ENOMEM;

                        fds = f;
                        memcpy(fds + n_fds, d->fds, sizeof(int) * j);
                        n_fds += j;
                        break;
                }

                case KDBUS_ITEM_SECLABEL:
                        seclabel = d->str;
                        break;
                }
        }

        if (!h)
                return -EBADMSG;

        r = bus_header_message_size(h, &total);
        if (r < 0)
                return r;

        if (n_bytes != total)
                return -EBADMSG;

        /* 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;

        /* 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);

                switch (d->type) {

                case KDBUS_ITEM_PAYLOAD_OFF: {
                        size_t begin_body;

                        begin_body = BUS_MESSAGE_BODY_BEGIN(m);

                        if (idx + d->vec.size > begin_body) {
                                struct bus_body_part *part;

                                /* Contains body material */

                                part = message_append_part(m);
                                if (!part) {
                                        r = -ENOMEM;
                                        goto fail;
                                }

                                /* A -1 offset is NUL padding. */
                                part->is_zero = d->vec.offset == ~0ULL;

                                if (idx >= begin_body) {
                                        if (!part->is_zero)
                                                part->data = (uint8_t *)k + d->vec.offset;
                                        part->size = d->vec.size;
                                } else {
                                        if (!part->is_zero)
                                                part->data = (uint8_t *)k + d->vec.offset + (begin_body - idx);
                                        part->size = d->vec.size - (begin_body - idx);
                                }

                                part->sealed = true;
                        }

                        idx += d->vec.size;
                        break;
                }

                case KDBUS_ITEM_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;
                        break;
                }

                case KDBUS_ITEM_CREDS:
                        /* UID/GID/PID are always valid */
                        m->creds.uid = (uid_t) d->creds.uid;
                        m->creds.gid = (gid_t) d->creds.gid;
                        m->creds.pid = (pid_t) d->creds.pid;
                        m->creds.mask |= (SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID) & bus->creds_mask;

                        /* The PID starttime/TID might be missing
                         * however, when the data is faked by some
                         * data bus proxy and it lacks that
                         * information about the real client since
                         * SO_PEERCRED is used for that */

                        if (d->creds.starttime > 0) {
                                m->creds.pid_starttime = d->creds.starttime / NSEC_PER_USEC;
                                m->creds.mask |= SD_BUS_CREDS_PID_STARTTIME & bus->creds_mask;
                        }

                        if (d->creds.tid > 0) {
                                m->creds.tid = (pid_t) d->creds.tid;
                                m->creds.mask |= SD_BUS_CREDS_TID & bus->creds_mask;
                        }
                        break;

                case KDBUS_ITEM_TIMESTAMP:

                        if (bus->attach_flags & KDBUS_ATTACH_TIMESTAMP) {
                                m->realtime = d->timestamp.realtime_ns / NSEC_PER_USEC;
                                m->monotonic = d->timestamp.monotonic_ns / NSEC_PER_USEC;
                                m->seqnum = d->timestamp.seqnum;
                        }

                        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;

                        r = bus_get_root_path(bus);
                        if (r < 0)
                                goto fail;

                        m->creds.cgroup_root = bus->cgroup_root;

                        break;

                case KDBUS_ITEM_AUDIT:
                        m->creds.audit_session_id = (uint32_t) d->audit.sessionid;
                        m->creds.audit_login_uid = (uid_t) 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:
                        if (!service_name_is_valid(d->str))
                                return -EBADMSG;

                        destination = d->str;
                        break;

                case KDBUS_ITEM_NAME:
                        if (!service_name_is_valid(d->name.name))
                                return -EBADMSG;

                        r = strv_extend(&m->creds.well_known_names, d->name.name);
                        if (r < 0)
                                goto fail;
                        break;

                case KDBUS_ITEM_CONN_NAME:
                        m->creds.conn_name = d->str;
                        m->creds.mask |= SD_BUS_CREDS_CONNECTION_NAME & bus->creds_mask;
                        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 = 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->creds.unique_name = m->sender_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->release_kdbus = true;
        m->free_fds = true;
        fds = NULL;

        bus->rqueue[bus->rqueue_size++] = m;

        return 1;

fail:
        unset_memfds(m);
        sd_bus_message_unref(m);

        return r;
}

int bus_kernel_take_fd(sd_bus *b) {
        struct kdbus_cmd_hello *hello;
        struct kdbus_item *item;
        _cleanup_free_ char *g = NULL;
        const char *name;
        size_t l = 0, m = 0, sz;
        int r;

        assert(b);

        if (b->is_server)
                return -EINVAL;

        b->use_memfd = 1;

        if (b->connection_name) {
                g = bus_label_escape(b->connection_name);
                if (!g)
                        return -ENOMEM;

                name = g;
        } else {
                char pr[17] = {};

                /* If no name is explicitly set, we'll include a hint
                 * indicating the library implementation, a hint which
                 * kind of bus this is and the thread name */

                assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0);

                if (isempty(pr)) {
                        name = b->is_system ? "sd-system" :
                                b->is_user ? "sd-user" : "sd";
                } else {
                        _cleanup_free_ char *e = NULL;

                        e = bus_label_escape(pr);
                        if (!e)
                                return -ENOMEM;

                        g = strappend(b->is_system ? "sd-system-" :
                                      b->is_user ? "sd-user-" : "sd-",
                                      e);
                        if (!g)
                                return -ENOMEM;

                        name = g;
                }

                b->connection_name = bus_label_unescape(name);
                if (!b->connection_name)
                        return -ENOMEM;
        }

        m = strlen(name);

        sz = ALIGN8(offsetof(struct kdbus_cmd_hello, items)) +
                ALIGN8(offsetof(struct kdbus_item, str) + m + 1);

        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 = alloca0_align(sz, 8);
        hello->size = sz;
        hello->flags = b->hello_flags;
        hello->attach_flags = b->attach_flags;
        hello->pool_size = KDBUS_POOL_SIZE;

        item = hello->items;

        item->size = offsetof(struct kdbus_item, str) + m + 1;
        item->type = KDBUS_ITEM_CONN_NAME;
        memcpy(item->str, name, m + 1);
        item = KDBUS_ITEM_NEXT(item);

        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;

                item = KDBUS_ITEM_NEXT(item);
        }

        if (b->fake_label) {
                item->size = offsetof(struct kdbus_item, str) + l + 1;
                item->type = KDBUS_ITEM_SECLABEL;
                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 the bus_flags fields are considered
         * 'incompatible flags'. Refuse them all for now. */
        if (hello->bus_flags > 0xFFFFFFFFULL)
                return -ENOTSUP;

        if (!bloom_validate_parameters((size_t) hello->bloom.size, (unsigned) hello->bloom.n_hash))
                return -ENOTSUP;

        b->bloom_size = (size_t) hello->bloom.size;
        b->bloom_n_hash = (unsigned) hello->bloom.n_hash;

        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 = !!(hello->flags & KDBUS_HELLO_ACCEPT_FD);
        b->message_version = 2;
        b->message_endian = BUS_NATIVE_ENDIAN;

        /* the kernel told us the UUID of the underlying bus */
        memcpy(b->server_id.bytes, hello->id128, sizeof(b->server_id.bytes));

        return bus_start_running(b);
}

int bus_kernel_connect(sd_bus *b) {
        assert(b);
        assert(b->input_fd < 0);
        assert(b->output_fd < 0);
        assert(b->kernel);

        if (b->is_server)
                return -EINVAL;

        b->input_fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC);
        if (b->input_fd < 0)
                return -errno;

        b->output_fd = b->input_fd;

        return bus_kernel_take_fd(b);
}

static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
        struct kdbus_cmd_free cmd;
        struct kdbus_item *d;

        assert(bus);
        assert(k);

        cmd.flags = 0;
        cmd.offset = (uint8_t *)k - (uint8_t *)bus->kdbus_buffer;

        KDBUS_ITEM_FOREACH(d, k, items) {

                if (d->type == KDBUS_ITEM_FDS)
                        close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
                else if (d->type == KDBUS_ITEM_PAYLOAD_MEMFD)
                        safe_close(d->memfd.fd);
        }

        (void) ioctl(bus->input_fd, KDBUS_CMD_FREE, &cmd);
}

int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m, bool hint_sync_call) {
        int r;

        assert(bus);
        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;

        /* If this is a synchronous method call, then let's tell the
         * kernel, so that it can pass CPU time/scheduling to the
         * destination for the time, if it wants to. If we
         * synchronously wait for the result anyway, we won't need CPU
         * anyway. */
        if (hint_sync_call)
                m->kdbus->flags |= KDBUS_MSG_FLAGS_EXPECT_REPLY|KDBUS_MSG_FLAGS_SYNC_REPLY;

        r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus);
        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_COOKIE(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;

        } else if (hint_sync_call) {
                struct kdbus_msg *k;

                k = (struct kdbus_msg *)((uint8_t *)bus->kdbus_buffer + m->kdbus->offset_reply);
                assert(k);

                if (k->payload_type == KDBUS_PAYLOAD_DBUS) {

                        r = bus_kernel_make_message(bus, k);
                        if (r < 0) {
                                close_kdbus_msg(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));
                                else
                                        return r;
                        }
                } else {
                        log_debug("Ignoring message with unknown payload type %llu.", (unsigned long long) k->payload_type);
                        close_kdbus_msg(bus, k);
                }
        }

        return 1;
}

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,
                        &m,
                        "/org/freedesktop/DBus",
                        "org.freedesktop.DBus",
                        "NameOwnerChanged");
        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_id.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.id);

        if (d->type == KDBUS_ITEM_NAME_REMOVE || (d->name_change.new_id.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.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);
}

int bus_kernel_read_message(sd_bus *bus, bool hint_priority, int64_t priority) {
        struct kdbus_cmd_recv recv = {};
        struct kdbus_msg *k;
        int r;

        assert(bus);

        r = bus_rqueue_make_room(bus);
        if (r < 0)
                return r;

        if (hint_priority) {
                recv.flags |= KDBUS_RECV_USE_PRIORITY;
                recv.priority = priority;
        }

        r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &recv);
        if (r < 0) {
                if (errno == EAGAIN)
                        return 0;

                return -errno;
        }

        k = (struct kdbus_msg *)((uint8_t *)bus->kdbus_buffer + recv.offset);
        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 {
                log_debug("Ignoring message with unknown payload type %llu.", (unsigned long long) k->payload_type);
                r = 0;
        }

        if (r <= 0)
                close_kdbus_msg(bus, k);

        return r < 0 ? r : 1;
}

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) {
                _cleanup_free_ char *g = NULL;
                int r;

                assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);

                assert(bus->connection_name);

                g = bus_label_escape(bus->connection_name);
                if (!g)
                        return -ENOMEM;

                r = memfd_create(g, MFD_ALLOW_SEALING);
                if (r < 0)
                        return -errno;

                *address = NULL;
                *mapped = 0;
                *allocated = 0;
                return r;
        }

        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);

        safe_close(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(ftruncate(fd, 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)
                m |= KDBUS_ATTACH_PID_COMM;

        if (mask & SD_BUS_CREDS_TID_COMM)
                m |= KDBUS_ATTACH_TID_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;

        if (mask & SD_BUS_CREDS_CONNECTION_NAME)
                m |= KDBUS_ATTACH_CONN_NAME;

        *kdbus_mask = m;
        return 0;
}

int bus_kernel_create_bus(const char *name, bool world, char **s) {
        struct kdbus_cmd_make *make;
        struct kdbus_item *n;
        int fd;

        assert(name);
        assert(s);

        fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
        if (fd < 0)
                return -errno;

        make = alloca0_align(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),
                             8);

        make->size = offsetof(struct kdbus_cmd_make, items);

        n = make->items;
        n->size = offsetof(struct kdbus_item, bloom_parameter) +
                  sizeof(struct kdbus_bloom_parameter);
        n->type = KDBUS_ITEM_BLOOM_PARAMETER;

        n->bloom_parameter.size = DEFAULT_BLOOM_SIZE;
        n->bloom_parameter.n_hash = DEFAULT_BLOOM_N_HASH;

        assert_cc(DEFAULT_BLOOM_SIZE > 0);
        assert_cc(DEFAULT_BLOOM_N_HASH > 0);

        make->size += ALIGN8(n->size);

        n = KDBUS_ITEM_NEXT(n);
        sprintf(n->str, UID_FMT "-%s", getuid(), name);
        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
        n->type = KDBUS_ITEM_MAKE_NAME;
        make->size += ALIGN8(n->size);

        make->flags = world ? KDBUS_MAKE_ACCESS_WORLD : 0;

        if (ioctl(fd, KDBUS_CMD_BUS_MAKE, make) < 0) {
                safe_close(fd);
                return -errno;
        }

        if (s) {
                char *p;

                p = strjoin("/dev/kdbus/", n->str, "/bus", NULL);
                if (!p) {
                        safe_close(fd);
                        return -ENOMEM;
                }

                *s = p;
        }

        return fd;
}

static int bus_kernel_translate_access(BusPolicyAccess access) {
        assert(access >= 0);
        assert(access < _BUS_POLICY_ACCESS_MAX);

        switch (access) {

        case BUS_POLICY_ACCESS_SEE:
                return KDBUS_POLICY_SEE;

        case BUS_POLICY_ACCESS_TALK:
                return KDBUS_POLICY_TALK;

        case BUS_POLICY_ACCESS_OWN:
                return KDBUS_POLICY_OWN;

        default:
                assert_not_reached("Unknown policy access");
        }
}

static int bus_kernel_translate_policy(const BusNamePolicy *policy, struct kdbus_item *item) {
        int r;

        assert(policy);
        assert(item);

        switch (policy->type) {

        case BUSNAME_POLICY_TYPE_USER: {
                const char *user = policy->name;
                uid_t uid;

                r = get_user_creds(&user, &uid, NULL, NULL, NULL);
                if (r < 0)
                        return r;

                item->policy_access.type = KDBUS_POLICY_ACCESS_USER;
                item->policy_access.id = uid;
                break;
        }

        case BUSNAME_POLICY_TYPE_GROUP: {
                const char *group = policy->name;
                gid_t gid;

                r = get_group_creds(&group, &gid);
                if (r < 0)
                        return r;

                item->policy_access.type = KDBUS_POLICY_ACCESS_GROUP;
                item->policy_access.id = gid;
                break;
        }

        default:
                assert_not_reached("Unknown policy type");
        }

        item->policy_access.access = bus_kernel_translate_access(policy->access);

        return 0;
}

int bus_kernel_open_bus_fd(const char *bus, char **path) {
        char *p;
        int fd;
        size_t len;

        len = strlen("/dev/kdbus/") + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + strlen("/bus") + 1;

        if (path) {
                p = malloc(len);
                if (!p)
                        return -ENOMEM;
                *path = p;
        } else
                p = alloca(len);
        sprintf(p, "/dev/kdbus/" UID_FMT "-%s/bus", getuid(), bus);

        fd = open(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
        if (fd < 0)
                return -errno;

        return fd;
}

int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char **ep_path) {
        _cleanup_free_ char *path = NULL;
        struct kdbus_cmd_make *make;
        struct kdbus_item *n;
        size_t size;
        int fd;

        fd = bus_kernel_open_bus_fd(bus_name, &path);
        if (fd < 0)
                return fd;

        size = ALIGN8(offsetof(struct kdbus_cmd_make, items));
        size += ALIGN8(offsetof(struct kdbus_item, str) + strlen(ep_name) + 1);

        make = alloca0_align(size, 8);
        make->size = size;
        make->flags = KDBUS_MAKE_ACCESS_WORLD;

        n = make->items;

        n->type = KDBUS_ITEM_MAKE_NAME;
        n->size = offsetof(struct kdbus_item, str) + strlen(ep_name) + 1;
        strcpy(n->str, ep_name);

        if (ioctl(fd, KDBUS_CMD_ENDPOINT_MAKE, make) < 0) {
                safe_close(fd);
                return -errno;
        }

        if (ep_path) {
                char *p;

                p = strjoin(dirname(path), "/", ep_name, NULL);
                if (!p) {
                        safe_close(fd);
                        return -ENOMEM;
                }

                *ep_path = p;
        }

        return fd;
}

int bus_kernel_set_endpoint_policy(int fd, uid_t uid, BusEndpoint *ep) {

        struct kdbus_cmd_update *update;
        struct kdbus_item *n;
        BusEndpointPolicy *po;
        Iterator i;
        size_t size;
        int r;

        size = ALIGN8(offsetof(struct kdbus_cmd_update, items));

        HASHMAP_FOREACH(po, ep->policy_hash, i) {
                size += ALIGN8(offsetof(struct kdbus_item, str) + strlen(po->name) + 1);
                size += ALIGN8(offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access));
        }

        update = alloca0_align(size, 8);
        update->size = size;

        n = update->items;

        HASHMAP_FOREACH(po, ep->policy_hash, i) {
                n->type = KDBUS_ITEM_NAME;
                n->size = offsetof(struct kdbus_item, str) + strlen(po->name) + 1;
                strcpy(n->str, po->name);
                n = KDBUS_ITEM_NEXT(n);

                n->type = KDBUS_ITEM_POLICY_ACCESS;
                n->size = offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access);

                n->policy_access.type = KDBUS_POLICY_ACCESS_USER;
                n->policy_access.access = bus_kernel_translate_access(po->access);
                n->policy_access.id = uid;

                n = KDBUS_ITEM_NEXT(n);
        }

        r = ioctl(fd, KDBUS_CMD_ENDPOINT_UPDATE, update);
        if (r < 0)
                return -errno;

        return 0;
}

int bus_kernel_make_starter(
                int fd,
                const char *name,
                bool activating,
                bool accept_fd,
                BusNamePolicy *policy,
                BusPolicyAccess world_policy) {

        struct kdbus_cmd_hello *hello;
        struct kdbus_item *n;
        size_t policy_cnt = 0;
        BusNamePolicy *po;
        size_t size;
        int r;

        assert(fd >= 0);
        assert(name);

        LIST_FOREACH(policy, po, policy)
                policy_cnt++;

        if (world_policy >= 0)
                policy_cnt++;

        size = ALIGN8(offsetof(struct kdbus_cmd_hello, items)) +
               ALIGN8(offsetof(struct kdbus_item, str) + strlen(name) + 1) +
               policy_cnt * ALIGN8(offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access));

        hello = alloca0_align(size, 8);

        n = hello->items;
        strcpy(n->str, name);
        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
        n->type = KDBUS_ITEM_NAME;
        n = KDBUS_ITEM_NEXT(n);

        LIST_FOREACH(policy, po, policy) {
                n->type = KDBUS_ITEM_POLICY_ACCESS;
                n->size = offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access);

                r = bus_kernel_translate_policy(po, n);
                if (r < 0)
                        return r;

                n = KDBUS_ITEM_NEXT(n);
        }

        if (world_policy >= 0) {
                n->type = KDBUS_ITEM_POLICY_ACCESS;
                n->size = offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access);
                n->policy_access.type = KDBUS_POLICY_ACCESS_WORLD;
                n->policy_access.access = bus_kernel_translate_access(world_policy);
        }

        hello->size = size;
        hello->flags =
                (activating ? KDBUS_HELLO_ACTIVATOR : KDBUS_HELLO_POLICY_HOLDER) |
                (accept_fd ? KDBUS_HELLO_ACCEPT_FD : 0);
        hello->pool_size = KDBUS_POOL_SIZE;
        hello->attach_flags = _KDBUS_ATTACH_ALL;

        if (ioctl(fd, KDBUS_CMD_HELLO, hello) < 0)
                return -errno;

        /* The higher 32bit of the bus_flags fields are considered
         * 'incompatible flags'. Refuse them all for now. */
        if (hello->bus_flags > 0xFFFFFFFFULL)
                return -ENOTSUP;

        if (!bloom_validate_parameters((size_t) hello->bloom.size, (unsigned) hello->bloom.n_hash))
                return -ENOTSUP;

        return fd;
}

int bus_kernel_create_domain(const char *name, char **s) {
        struct kdbus_cmd_make *make;
        struct kdbus_item *n;
        int fd;

        assert(name);
        assert(s);

        fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
        if (fd < 0)
                return -errno;

        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items) +
                                    offsetof(struct kdbus_item, str) +
                                    strlen(name) + 1),
                             8);

        n = make->items;
        strcpy(n->str, name);
        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
        n->type = KDBUS_ITEM_MAKE_NAME;

        make->size = ALIGN8(offsetof(struct kdbus_cmd_make, items) + n->size);
        make->flags = KDBUS_MAKE_ACCESS_WORLD;

        if (ioctl(fd, KDBUS_CMD_DOMAIN_MAKE, make) < 0) {
                safe_close(fd);
                return -errno;
        }

        /* The higher 32bit of the flags field are considered
         * 'incompatible flags'. Refuse them all for now. */
        if (make->flags > 0xFFFFFFFFULL) {
                safe_close(fd);
                return -ENOTSUP;
        }

        if (s) {
                char *p;

                p = strappend("/dev/kdbus/domain/", name);
                if (!p) {
                        safe_close(fd);
                        return -ENOMEM;
                }

                *s = p;
        }

        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;
}

int bus_kernel_drop_one(int fd) {
        struct kdbus_cmd_recv recv = {
                .flags = KDBUS_RECV_DROP
        };

        assert(fd >= 0);

        if (ioctl(fd, KDBUS_CMD_MSG_RECV, &recv) < 0)
                return -errno;

        return 0;
}