Adding upstream version 241.upstream/241upstream

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

1 files changed, 5593 insertions, 0 deletions

diff --git a/src/core/unit.c b/src/core/unit.c
new file mode 100644
index 0000000..24b14fb
--- /dev/null
+++ b/src/core/unit.c
@@ -0,0 +1,5593 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "sd-id128.h"
+#include "sd-messages.h"
+
+#include "all-units.h"
+#include "alloc-util.h"
+#include "bus-common-errors.h"
+#include "bus-util.h"
+#include "cgroup-util.h"
+#include "dbus-unit.h"
+#include "dbus.h"
+#include "dropin.h"
+#include "escape.h"
+#include "execute.h"
+#include "fd-util.h"
+#include "fileio-label.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "id128-util.h"
+#include "io-util.h"
+#include "load-dropin.h"
+#include "load-fragment.h"
+#include "log.h"
+#include "macro.h"
+#include "missing.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "serialize.h"
+#include "set.h"
+#include "signal-util.h"
+#include "sparse-endian.h"
+#include "special.h"
+#include "specifier.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "tmpfile-util.h"
+#include "umask-util.h"
+#include "unit-name.h"
+#include "unit.h"
+#include "user-util.h"
+#include "virt.h"
+
+const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX] = {
+        [UNIT_SERVICE] = &service_vtable,
+        [UNIT_SOCKET] = &socket_vtable,
+        [UNIT_TARGET] = &target_vtable,
+        [UNIT_DEVICE] = &device_vtable,
+        [UNIT_MOUNT] = &mount_vtable,
+        [UNIT_AUTOMOUNT] = &automount_vtable,
+        [UNIT_SWAP] = &swap_vtable,
+        [UNIT_TIMER] = &timer_vtable,
+        [UNIT_PATH] = &path_vtable,
+        [UNIT_SLICE] = &slice_vtable,
+        [UNIT_SCOPE] = &scope_vtable,
+};
+
+static void maybe_warn_about_dependency(Unit *u, const char *other, UnitDependency dependency);
+
+Unit *unit_new(Manager *m, size_t size) {
+        Unit *u;
+
+        assert(m);
+        assert(size >= sizeof(Unit));
+
+        u = malloc0(size);
+        if (!u)
+                return NULL;
+
+        u->names = set_new(&string_hash_ops);
+        if (!u->names)
+                return mfree(u);
+
+        u->manager = m;
+        u->type = _UNIT_TYPE_INVALID;
+        u->default_dependencies = true;
+        u->unit_file_state = _UNIT_FILE_STATE_INVALID;
+        u->unit_file_preset = -1;
+        u->on_failure_job_mode = JOB_REPLACE;
+        u->cgroup_inotify_wd = -1;
+        u->job_timeout = USEC_INFINITY;
+        u->job_running_timeout = USEC_INFINITY;
+        u->ref_uid = UID_INVALID;
+        u->ref_gid = GID_INVALID;
+        u->cpu_usage_last = NSEC_INFINITY;
+        u->cgroup_invalidated_mask |= CGROUP_MASK_BPF_FIREWALL;
+        u->failure_action_exit_status = u->success_action_exit_status = -1;
+
+        u->ip_accounting_ingress_map_fd = -1;
+        u->ip_accounting_egress_map_fd = -1;
+        u->ipv4_allow_map_fd = -1;
+        u->ipv6_allow_map_fd = -1;
+        u->ipv4_deny_map_fd = -1;
+        u->ipv6_deny_map_fd = -1;
+
+        u->last_section_private = -1;
+
+        RATELIMIT_INIT(u->start_limit, m->default_start_limit_interval, m->default_start_limit_burst);
+        RATELIMIT_INIT(u->auto_stop_ratelimit, 10 * USEC_PER_SEC, 16);
+
+        return u;
+}
+
+int unit_new_for_name(Manager *m, size_t size, const char *name, Unit **ret) {
+        _cleanup_(unit_freep) Unit *u = NULL;
+        int r;
+
+        u = unit_new(m, size);
+        if (!u)
+                return -ENOMEM;
+
+        r = unit_add_name(u, name);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(u);
+
+        return r;
+}
+
+bool unit_has_name(const Unit *u, const char *name) {
+        assert(u);
+        assert(name);
+
+        return set_contains(u->names, (char*) name);
+}
+
+static void unit_init(Unit *u) {
+        CGroupContext *cc;
+        ExecContext *ec;
+        KillContext *kc;
+
+        assert(u);
+        assert(u->manager);
+        assert(u->type >= 0);
+
+        cc = unit_get_cgroup_context(u);
+        if (cc) {
+                cgroup_context_init(cc);
+
+                /* Copy in the manager defaults into the cgroup
+                 * context, _before_ the rest of the settings have
+                 * been initialized */
+
+                cc->cpu_accounting = u->manager->default_cpu_accounting;
+                cc->io_accounting = u->manager->default_io_accounting;
+                cc->ip_accounting = u->manager->default_ip_accounting;
+                cc->blockio_accounting = u->manager->default_blockio_accounting;
+                cc->memory_accounting = u->manager->default_memory_accounting;
+                cc->tasks_accounting = u->manager->default_tasks_accounting;
+                cc->ip_accounting = u->manager->default_ip_accounting;
+
+                if (u->type != UNIT_SLICE)
+                        cc->tasks_max = u->manager->default_tasks_max;
+        }
+
+        ec = unit_get_exec_context(u);
+        if (ec) {
+                exec_context_init(ec);
+
+                ec->keyring_mode = MANAGER_IS_SYSTEM(u->manager) ?
+                        EXEC_KEYRING_SHARED : EXEC_KEYRING_INHERIT;
+        }
+
+        kc = unit_get_kill_context(u);
+        if (kc)
+                kill_context_init(kc);
+
+        if (UNIT_VTABLE(u)->init)
+                UNIT_VTABLE(u)->init(u);
+}
+
+int unit_add_name(Unit *u, const char *text) {
+        _cleanup_free_ char *s = NULL, *i = NULL;
+        UnitType t;
+        int r;
+
+        assert(u);
+        assert(text);
+
+        if (unit_name_is_valid(text, UNIT_NAME_TEMPLATE)) {
+
+                if (!u->instance)
+                        return -EINVAL;
+
+                r = unit_name_replace_instance(text, u->instance, &s);
+                if (r < 0)
+                        return r;
+        } else {
+                s = strdup(text);
+                if (!s)
+                        return -ENOMEM;
+        }
+
+        if (set_contains(u->names, s))
+                return 0;
+        if (hashmap_contains(u->manager->units, s))
+                return -EEXIST;
+
+        if (!unit_name_is_valid(s, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
+                return -EINVAL;
+
+        t = unit_name_to_type(s);
+        if (t < 0)
+                return -EINVAL;
+
+        if (u->type != _UNIT_TYPE_INVALID && t != u->type)
+                return -EINVAL;
+
+        r = unit_name_to_instance(s, &i);
+        if (r < 0)
+                return r;
+
+        if (i && !unit_type_may_template(t))
+                return -EINVAL;
+
+        /* Ensure that this unit is either instanced or not instanced,
+         * but not both. Note that we do allow names with different
+         * instance names however! */
+        if (u->type != _UNIT_TYPE_INVALID && !u->instance != !i)
+                return -EINVAL;
+
+        if (!unit_type_may_alias(t) && !set_isempty(u->names))
+                return -EEXIST;
+
+        if (hashmap_size(u->manager->units) >= MANAGER_MAX_NAMES)
+                return -E2BIG;
+
+        r = set_put(u->names, s);
+        if (r < 0)
+                return r;
+        assert(r > 0);
+
+        r = hashmap_put(u->manager->units, s, u);
+        if (r < 0) {
+                (void) set_remove(u->names, s);
+                return r;
+        }
+
+        if (u->type == _UNIT_TYPE_INVALID) {
+                u->type = t;
+                u->id = s;
+                u->instance = TAKE_PTR(i);
+
+                LIST_PREPEND(units_by_type, u->manager->units_by_type[t], u);
+
+                unit_init(u);
+        }
+
+        s = NULL;
+
+        unit_add_to_dbus_queue(u);
+        return 0;
+}
+
+int unit_choose_id(Unit *u, const char *name) {
+        _cleanup_free_ char *t = NULL;
+        char *s, *i;
+        int r;
+
+        assert(u);
+        assert(name);
+
+        if (unit_name_is_valid(name, UNIT_NAME_TEMPLATE)) {
+
+                if (!u->instance)
+                        return -EINVAL;
+
+                r = unit_name_replace_instance(name, u->instance, &t);
+                if (r < 0)
+                        return r;
+
+                name = t;
+        }
+
+        /* Selects one of the names of this unit as the id */
+        s = set_get(u->names, (char*) name);
+        if (!s)
+                return -ENOENT;
+
+        /* Determine the new instance from the new id */
+        r = unit_name_to_instance(s, &i);
+        if (r < 0)
+                return r;
+
+        u->id = s;
+
+        free(u->instance);
+        u->instance = i;
+
+        unit_add_to_dbus_queue(u);
+
+        return 0;
+}
+
+int unit_set_description(Unit *u, const char *description) {
+        int r;
+
+        assert(u);
+
+        r = free_and_strdup(&u->description, empty_to_null(description));
+        if (r < 0)
+                return r;
+        if (r > 0)
+                unit_add_to_dbus_queue(u);
+
+        return 0;
+}
+
+bool unit_may_gc(Unit *u) {
+        UnitActiveState state;
+        int r;
+
+        assert(u);
+
+        /* Checks whether the unit is ready to be unloaded for garbage collection.
+         * Returns true when the unit may be collected, and false if there's some
+         * reason to keep it loaded.
+         *
+         * References from other units are *not* checked here. Instead, this is done
+         * in unit_gc_sweep(), but using markers to properly collect dependency loops.
+         */
+
+        if (u->job)
+                return false;
+
+        if (u->nop_job)
+                return false;
+
+        state = unit_active_state(u);
+
+        /* If the unit is inactive and failed and no job is queued for it, then release its runtime resources */
+        if (UNIT_IS_INACTIVE_OR_FAILED(state) &&
+            UNIT_VTABLE(u)->release_resources)
+                UNIT_VTABLE(u)->release_resources(u);
+
+        if (u->perpetual)
+                return false;
+
+        if (sd_bus_track_count(u->bus_track) > 0)
+                return false;
+
+        /* But we keep the unit object around for longer when it is referenced or configured to not be gc'ed */
+        switch (u->collect_mode) {
+
+        case COLLECT_INACTIVE:
+                if (state != UNIT_INACTIVE)
+                        return false;
+
+                break;
+
+        case COLLECT_INACTIVE_OR_FAILED:
+                if (!IN_SET(state, UNIT_INACTIVE, UNIT_FAILED))
+                        return false;
+
+                break;
+
+        default:
+                assert_not_reached("Unknown garbage collection mode");
+        }
+
+        if (u->cgroup_path) {
+                /* If the unit has a cgroup, then check whether there's anything in it. If so, we should stay
+                 * around. Units with active processes should never be collected. */
+
+                r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path);
+                if (r < 0)
+                        log_unit_debug_errno(u, r, "Failed to determine whether cgroup %s is empty: %m", u->cgroup_path);
+                if (r <= 0)
+                        return false;
+        }
+
+        if (UNIT_VTABLE(u)->may_gc && !UNIT_VTABLE(u)->may_gc(u))
+                return false;
+
+        return true;
+}
+
+void unit_add_to_load_queue(Unit *u) {
+        assert(u);
+        assert(u->type != _UNIT_TYPE_INVALID);
+
+        if (u->load_state != UNIT_STUB || u->in_load_queue)
+                return;
+
+        LIST_PREPEND(load_queue, u->manager->load_queue, u);
+        u->in_load_queue = true;
+}
+
+void unit_add_to_cleanup_queue(Unit *u) {
+        assert(u);
+
+        if (u->in_cleanup_queue)
+                return;
+
+        LIST_PREPEND(cleanup_queue, u->manager->cleanup_queue, u);
+        u->in_cleanup_queue = true;
+}
+
+void unit_add_to_gc_queue(Unit *u) {
+        assert(u);
+
+        if (u->in_gc_queue || u->in_cleanup_queue)
+                return;
+
+        if (!unit_may_gc(u))
+                return;
+
+        LIST_PREPEND(gc_queue, u->manager->gc_unit_queue, u);
+        u->in_gc_queue = true;
+}
+
+void unit_add_to_dbus_queue(Unit *u) {
+        assert(u);
+        assert(u->type != _UNIT_TYPE_INVALID);
+
+        if (u->load_state == UNIT_STUB || u->in_dbus_queue)
+                return;
+
+        /* Shortcut things if nobody cares */
+        if (sd_bus_track_count(u->manager->subscribed) <= 0 &&
+            sd_bus_track_count(u->bus_track) <= 0 &&
+            set_isempty(u->manager->private_buses)) {
+                u->sent_dbus_new_signal = true;
+                return;
+        }
+
+        LIST_PREPEND(dbus_queue, u->manager->dbus_unit_queue, u);
+        u->in_dbus_queue = true;
+}
+
+void unit_submit_to_stop_when_unneeded_queue(Unit *u) {
+        assert(u);
+
+        if (u->in_stop_when_unneeded_queue)
+                return;
+
+        if (!u->stop_when_unneeded)
+                return;
+
+        if (!UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u)))
+                return;
+
+        LIST_PREPEND(stop_when_unneeded_queue, u->manager->stop_when_unneeded_queue, u);
+        u->in_stop_when_unneeded_queue = true;
+}
+
+static void bidi_set_free(Unit *u, Hashmap *h) {
+        Unit *other;
+        Iterator i;
+        void *v;
+
+        assert(u);
+
+        /* Frees the hashmap and makes sure we are dropped from the inverse pointers */
+
+        HASHMAP_FOREACH_KEY(v, other, h, i) {
+                UnitDependency d;
+
+                for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+                        hashmap_remove(other->dependencies[d], u);
+
+                unit_add_to_gc_queue(other);
+        }
+
+        hashmap_free(h);
+}
+
+static void unit_remove_transient(Unit *u) {
+        char **i;
+
+        assert(u);
+
+        if (!u->transient)
+                return;
+
+        if (u->fragment_path)
+                (void) unlink(u->fragment_path);
+
+        STRV_FOREACH(i, u->dropin_paths) {
+                _cleanup_free_ char *p = NULL, *pp = NULL;
+
+                p = dirname_malloc(*i); /* Get the drop-in directory from the drop-in file */
+                if (!p)
+                        continue;
+
+                pp = dirname_malloc(p); /* Get the config directory from the drop-in directory */
+                if (!pp)
+                        continue;
+
+                /* Only drop transient drop-ins */
+                if (!path_equal(u->manager->lookup_paths.transient, pp))
+                        continue;
+
+                (void) unlink(*i);
+                (void) rmdir(p);
+        }
+}
+
+static void unit_free_requires_mounts_for(Unit *u) {
+        assert(u);
+
+        for (;;) {
+                _cleanup_free_ char *path;
+
+                path = hashmap_steal_first_key(u->requires_mounts_for);
+                if (!path)
+                        break;
+                else {
+                        char s[strlen(path) + 1];
+
+                        PATH_FOREACH_PREFIX_MORE(s, path) {
+                                char *y;
+                                Set *x;
+
+                                x = hashmap_get2(u->manager->units_requiring_mounts_for, s, (void**) &y);
+                                if (!x)
+                                        continue;
+
+                                (void) set_remove(x, u);
+
+                                if (set_isempty(x)) {
+                                        (void) hashmap_remove(u->manager->units_requiring_mounts_for, y);
+                                        free(y);
+                                        set_free(x);
+                                }
+                        }
+                }
+        }
+
+        u->requires_mounts_for = hashmap_free(u->requires_mounts_for);
+}
+
+static void unit_done(Unit *u) {
+        ExecContext *ec;
+        CGroupContext *cc;
+
+        assert(u);
+
+        if (u->type < 0)
+                return;
+
+        if (UNIT_VTABLE(u)->done)
+                UNIT_VTABLE(u)->done(u);
+
+        ec = unit_get_exec_context(u);
+        if (ec)
+                exec_context_done(ec);
+
+        cc = unit_get_cgroup_context(u);
+        if (cc)
+                cgroup_context_done(cc);
+}
+
+void unit_free(Unit *u) {
+        UnitDependency d;
+        Iterator i;
+        char *t;
+
+        if (!u)
+                return;
+
+        if (UNIT_ISSET(u->slice)) {
+                /* A unit is being dropped from the tree, make sure our parent slice recalculates the member mask */
+                unit_invalidate_cgroup_members_masks(UNIT_DEREF(u->slice));
+
+                /* And make sure the parent is realized again, updating cgroup memberships */
+                unit_add_to_cgroup_realize_queue(UNIT_DEREF(u->slice));
+        }
+
+        u->transient_file = safe_fclose(u->transient_file);
+
+        if (!MANAGER_IS_RELOADING(u->manager))
+                unit_remove_transient(u);
+
+        bus_unit_send_removed_signal(u);
+
+        unit_done(u);
+
+        unit_dequeue_rewatch_pids(u);
+
+        sd_bus_slot_unref(u->match_bus_slot);
+        sd_bus_track_unref(u->bus_track);
+        u->deserialized_refs = strv_free(u->deserialized_refs);
+
+        unit_free_requires_mounts_for(u);
+
+        SET_FOREACH(t, u->names, i)
+                hashmap_remove_value(u->manager->units, t, u);
+
+        if (!sd_id128_is_null(u->invocation_id))
+                hashmap_remove_value(u->manager->units_by_invocation_id, &u->invocation_id, u);
+
+        if (u->job) {
+                Job *j = u->job;
+                job_uninstall(j);
+                job_free(j);
+        }
+
+        if (u->nop_job) {
+                Job *j = u->nop_job;
+                job_uninstall(j);
+                job_free(j);
+        }
+
+        for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+                bidi_set_free(u, u->dependencies[d]);
+
+        if (u->on_console)
+                manager_unref_console(u->manager);
+
+        unit_release_cgroup(u);
+
+        if (!MANAGER_IS_RELOADING(u->manager))
+                unit_unlink_state_files(u);
+
+        unit_unref_uid_gid(u, false);
+
+        (void) manager_update_failed_units(u->manager, u, false);
+        set_remove(u->manager->startup_units, u);
+
+        unit_unwatch_all_pids(u);
+
+        unit_ref_unset(&u->slice);
+        while (u->refs_by_target)
+                unit_ref_unset(u->refs_by_target);
+
+        if (u->type != _UNIT_TYPE_INVALID)
+                LIST_REMOVE(units_by_type, u->manager->units_by_type[u->type], u);
+
+        if (u->in_load_queue)
+                LIST_REMOVE(load_queue, u->manager->load_queue, u);
+
+        if (u->in_dbus_queue)
+                LIST_REMOVE(dbus_queue, u->manager->dbus_unit_queue, u);
+
+        if (u->in_gc_queue)
+                LIST_REMOVE(gc_queue, u->manager->gc_unit_queue, u);
+
+        if (u->in_cgroup_realize_queue)
+                LIST_REMOVE(cgroup_realize_queue, u->manager->cgroup_realize_queue, u);
+
+        if (u->in_cgroup_empty_queue)
+                LIST_REMOVE(cgroup_empty_queue, u->manager->cgroup_empty_queue, u);
+
+        if (u->in_cleanup_queue)
+                LIST_REMOVE(cleanup_queue, u->manager->cleanup_queue, u);
+
+        if (u->in_target_deps_queue)
+                LIST_REMOVE(target_deps_queue, u->manager->target_deps_queue, u);
+
+        if (u->in_stop_when_unneeded_queue)
+                LIST_REMOVE(stop_when_unneeded_queue, u->manager->stop_when_unneeded_queue, u);
+
+        safe_close(u->ip_accounting_ingress_map_fd);
+        safe_close(u->ip_accounting_egress_map_fd);
+
+        safe_close(u->ipv4_allow_map_fd);
+        safe_close(u->ipv6_allow_map_fd);
+        safe_close(u->ipv4_deny_map_fd);
+        safe_close(u->ipv6_deny_map_fd);
+
+        bpf_program_unref(u->ip_bpf_ingress);
+        bpf_program_unref(u->ip_bpf_ingress_installed);
+        bpf_program_unref(u->ip_bpf_egress);
+        bpf_program_unref(u->ip_bpf_egress_installed);
+
+        bpf_program_unref(u->bpf_device_control_installed);
+
+        condition_free_list(u->conditions);
+        condition_free_list(u->asserts);
+
+        free(u->description);
+        strv_free(u->documentation);
+        free(u->fragment_path);
+        free(u->source_path);
+        strv_free(u->dropin_paths);
+        free(u->instance);
+
+        free(u->job_timeout_reboot_arg);
+
+        set_free_free(u->names);
+
+        free(u->reboot_arg);
+
+        free(u);
+}
+
+UnitActiveState unit_active_state(Unit *u) {
+        assert(u);
+
+        if (u->load_state == UNIT_MERGED)
+                return unit_active_state(unit_follow_merge(u));
+
+        /* After a reload it might happen that a unit is not correctly
+         * loaded but still has a process around. That's why we won't
+         * shortcut failed loading to UNIT_INACTIVE_FAILED. */
+
+        return UNIT_VTABLE(u)->active_state(u);
+}
+
+const char* unit_sub_state_to_string(Unit *u) {
+        assert(u);
+
+        return UNIT_VTABLE(u)->sub_state_to_string(u);
+}
+
+static int set_complete_move(Set **s, Set **other) {
+        assert(s);
+        assert(other);
+
+        if (!other)
+                return 0;
+
+        if (*s)
+                return set_move(*s, *other);
+        else
+                *s = TAKE_PTR(*other);
+
+        return 0;
+}
+
+static int hashmap_complete_move(Hashmap **s, Hashmap **other) {
+        assert(s);
+        assert(other);
+
+        if (!*other)
+                return 0;
+
+        if (*s)
+                return hashmap_move(*s, *other);
+        else
+                *s = TAKE_PTR(*other);
+
+        return 0;
+}
+
+static int merge_names(Unit *u, Unit *other) {
+        char *t;
+        Iterator i;
+        int r;
+
+        assert(u);
+        assert(other);
+
+        r = set_complete_move(&u->names, &other->names);
+        if (r < 0)
+                return r;
+
+        set_free_free(other->names);
+        other->names = NULL;
+        other->id = NULL;
+
+        SET_FOREACH(t, u->names, i)
+                assert_se(hashmap_replace(u->manager->units, t, u) == 0);
+
+        return 0;
+}
+
+static int reserve_dependencies(Unit *u, Unit *other, UnitDependency d) {
+        unsigned n_reserve;
+
+        assert(u);
+        assert(other);
+        assert(d < _UNIT_DEPENDENCY_MAX);
+
+        /*
+         * If u does not have this dependency set allocated, there is no need
+         * to reserve anything. In that case other's set will be transferred
+         * as a whole to u by complete_move().
+         */
+        if (!u->dependencies[d])
+                return 0;
+
+        /* merge_dependencies() will skip a u-on-u dependency */
+        n_reserve = hashmap_size(other->dependencies[d]) - !!hashmap_get(other->dependencies[d], u);
+
+        return hashmap_reserve(u->dependencies[d], n_reserve);
+}
+
+static void merge_dependencies(Unit *u, Unit *other, const char *other_id, UnitDependency d) {
+        Iterator i;
+        Unit *back;
+        void *v;
+        int r;
+
+        /* Merges all dependencies of type 'd' of the unit 'other' into the deps of the unit 'u' */
+
+        assert(u);
+        assert(other);
+        assert(d < _UNIT_DEPENDENCY_MAX);
+
+        /* Fix backwards pointers. Let's iterate through all dependendent units of the other unit. */
+        HASHMAP_FOREACH_KEY(v, back, other->dependencies[d], i) {
+                UnitDependency k;
+
+                /* Let's now iterate through the dependencies of that dependencies of the other units, looking for
+                 * pointers back, and let's fix them up, to instead point to 'u'. */
+
+                for (k = 0; k < _UNIT_DEPENDENCY_MAX; k++) {
+                        if (back == u) {
+                                /* Do not add dependencies between u and itself. */
+                                if (hashmap_remove(back->dependencies[k], other))
+                                        maybe_warn_about_dependency(u, other_id, k);
+                        } else {
+                                UnitDependencyInfo di_u, di_other, di_merged;
+
+                                /* Let's drop this dependency between "back" and "other", and let's create it between
+                                 * "back" and "u" instead. Let's merge the bit masks of the dependency we are moving,
+                                 * and any such dependency which might already exist */
+
+                                di_other.data = hashmap_get(back->dependencies[k], other);
+                                if (!di_other.data)
+                                        continue; /* dependency isn't set, let's try the next one */
+
+                                di_u.data = hashmap_get(back->dependencies[k], u);
+
+                                di_merged = (UnitDependencyInfo) {
+                                        .origin_mask = di_u.origin_mask | di_other.origin_mask,
+                                        .destination_mask = di_u.destination_mask | di_other.destination_mask,
+                                };
+
+                                r = hashmap_remove_and_replace(back->dependencies[k], other, u, di_merged.data);
+                                if (r < 0)
+                                        log_warning_errno(r, "Failed to remove/replace: back=%s other=%s u=%s: %m", back->id, other_id, u->id);
+                                assert(r >= 0);
+
+                                /* assert_se(hashmap_remove_and_replace(back->dependencies[k], other, u, di_merged.data) >= 0); */
+                        }
+                }
+
+        }
+
+        /* Also do not move dependencies on u to itself */
+        back = hashmap_remove(other->dependencies[d], u);
+        if (back)
+                maybe_warn_about_dependency(u, other_id, d);
+
+        /* The move cannot fail. The caller must have performed a reservation. */
+        assert_se(hashmap_complete_move(&u->dependencies[d], &other->dependencies[d]) == 0);
+
+        other->dependencies[d] = hashmap_free(other->dependencies[d]);
+}
+
+int unit_merge(Unit *u, Unit *other) {
+        UnitDependency d;
+        const char *other_id = NULL;
+        int r;
+
+        assert(u);
+        assert(other);
+        assert(u->manager == other->manager);
+        assert(u->type != _UNIT_TYPE_INVALID);
+
+        other = unit_follow_merge(other);
+
+        if (other == u)
+                return 0;
+
+        if (u->type != other->type)
+                return -EINVAL;
+
+        if (!u->instance != !other->instance)
+                return -EINVAL;
+
+        if (!unit_type_may_alias(u->type)) /* Merging only applies to unit names that support aliases */
+                return -EEXIST;
+
+        if (!IN_SET(other->load_state, UNIT_STUB, UNIT_NOT_FOUND))
+                return -EEXIST;
+
+        if (other->job)
+                return -EEXIST;
+
+        if (other->nop_job)
+                return -EEXIST;
+
+        if (!UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other)))
+                return -EEXIST;
+
+        if (other->id)
+                other_id = strdupa(other->id);
+
+        /* Make reservations to ensure merge_dependencies() won't fail */
+        for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
+                r = reserve_dependencies(u, other, d);
+                /*
+                 * We don't rollback reservations if we fail. We don't have
+                 * a way to undo reservations. A reservation is not a leak.
+                 */
+                if (r < 0)
+                        return r;
+        }
+
+        /* Merge names */
+        r = merge_names(u, other);
+        if (r < 0)
+                return r;
+
+        /* Redirect all references */
+        while (other->refs_by_target)
+                unit_ref_set(other->refs_by_target, other->refs_by_target->source, u);
+
+        /* Merge dependencies */
+        for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+                merge_dependencies(u, other, other_id, d);
+
+        other->load_state = UNIT_MERGED;
+        other->merged_into = u;
+
+        /* If there is still some data attached to the other node, we
+         * don't need it anymore, and can free it. */
+        if (other->load_state != UNIT_STUB)
+                if (UNIT_VTABLE(other)->done)
+                        UNIT_VTABLE(other)->done(other);
+
+        unit_add_to_dbus_queue(u);
+        unit_add_to_cleanup_queue(other);
+
+        return 0;
+}
+
+int unit_merge_by_name(Unit *u, const char *name) {
+        _cleanup_free_ char *s = NULL;
+        Unit *other;
+        int r;
+
+        assert(u);
+        assert(name);
+
+        if (unit_name_is_valid(name, UNIT_NAME_TEMPLATE)) {
+                if (!u->instance)
+                        return -EINVAL;
+
+                r = unit_name_replace_instance(name, u->instance, &s);
+                if (r < 0)
+                        return r;
+
+                name = s;
+        }
+
+        other = manager_get_unit(u->manager, name);
+        if (other)
+                return unit_merge(u, other);
+
+        return unit_add_name(u, name);
+}
+
+Unit* unit_follow_merge(Unit *u) {
+        assert(u);
+
+        while (u->load_state == UNIT_MERGED)
+                assert_se(u = u->merged_into);
+
+        return u;
+}
+
+int unit_add_exec_dependencies(Unit *u, ExecContext *c) {
+        ExecDirectoryType dt;
+        char **dp;
+        int r;
+
+        assert(u);
+        assert(c);
+
+        if (c->working_directory && !c->working_directory_missing_ok) {
+                r = unit_require_mounts_for(u, c->working_directory, UNIT_DEPENDENCY_FILE);
+                if (r < 0)
+                        return r;
+        }
+
+        if (c->root_directory) {
+                r = unit_require_mounts_for(u, c->root_directory, UNIT_DEPENDENCY_FILE);
+                if (r < 0)
+                        return r;
+        }
+
+        if (c->root_image) {
+                r = unit_require_mounts_for(u, c->root_image, UNIT_DEPENDENCY_FILE);
+                if (r < 0)
+                        return r;
+        }
+
+        for (dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) {
+                if (!u->manager->prefix[dt])
+                        continue;
+
+                STRV_FOREACH(dp, c->directories[dt].paths) {
+                        _cleanup_free_ char *p;
+
+                        p = strjoin(u->manager->prefix[dt], "/", *dp);
+                        if (!p)
+                                return -ENOMEM;
+
+                        r = unit_require_mounts_for(u, p, UNIT_DEPENDENCY_FILE);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        if (!MANAGER_IS_SYSTEM(u->manager))
+                return 0;
+
+        if (c->private_tmp) {
+                const char *p;
+
+                FOREACH_STRING(p, "/tmp", "/var/tmp") {
+                        r = unit_require_mounts_for(u, p, UNIT_DEPENDENCY_FILE);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = unit_add_dependency_by_name(u, UNIT_AFTER, SPECIAL_TMPFILES_SETUP_SERVICE, true, UNIT_DEPENDENCY_FILE);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!IN_SET(c->std_output,
+                    EXEC_OUTPUT_JOURNAL, EXEC_OUTPUT_JOURNAL_AND_CONSOLE,
+                    EXEC_OUTPUT_KMSG, EXEC_OUTPUT_KMSG_AND_CONSOLE,
+                    EXEC_OUTPUT_SYSLOG, EXEC_OUTPUT_SYSLOG_AND_CONSOLE) &&
+            !IN_SET(c->std_error,
+                    EXEC_OUTPUT_JOURNAL, EXEC_OUTPUT_JOURNAL_AND_CONSOLE,
+                    EXEC_OUTPUT_KMSG, EXEC_OUTPUT_KMSG_AND_CONSOLE,
+                    EXEC_OUTPUT_SYSLOG, EXEC_OUTPUT_SYSLOG_AND_CONSOLE))
+                return 0;
+
+        /* If syslog or kernel logging is requested, make sure our own
+         * logging daemon is run first. */
+
+        r = unit_add_dependency_by_name(u, UNIT_AFTER, SPECIAL_JOURNALD_SOCKET, true, UNIT_DEPENDENCY_FILE);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+const char *unit_description(Unit *u) {
+        assert(u);
+
+        if (u->description)
+                return u->description;
+
+        return strna(u->id);
+}
+
+static void print_unit_dependency_mask(FILE *f, const char *kind, UnitDependencyMask mask, bool *space) {
+        const struct {
+                UnitDependencyMask mask;
+                const char *name;
+        } table[] = {
+                { UNIT_DEPENDENCY_FILE,               "file"               },
+                { UNIT_DEPENDENCY_IMPLICIT,           "implicit"           },
+                { UNIT_DEPENDENCY_DEFAULT,            "default"            },
+                { UNIT_DEPENDENCY_UDEV,               "udev"               },
+                { UNIT_DEPENDENCY_PATH,               "path"               },
+                { UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT, "mountinfo-implicit" },
+                { UNIT_DEPENDENCY_MOUNTINFO_DEFAULT,  "mountinfo-default"  },
+                { UNIT_DEPENDENCY_PROC_SWAP,          "proc-swap"          },
+        };
+        size_t i;
+
+        assert(f);
+        assert(kind);
+        assert(space);
+
+        for (i = 0; i < ELEMENTSOF(table); i++) {
+
+                if (mask == 0)
+                        break;
+
+                if (FLAGS_SET(mask, table[i].mask)) {
+                        if (*space)
+                                fputc(' ', f);
+                        else
+                                *space = true;
+
+                        fputs(kind, f);
+                        fputs("-", f);
+                        fputs(table[i].name, f);
+
+                        mask &= ~table[i].mask;
+                }
+        }
+
+        assert(mask == 0);
+}
+
+void unit_dump(Unit *u, FILE *f, const char *prefix) {
+        char *t, **j;
+        UnitDependency d;
+        Iterator i;
+        const char *prefix2;
+        char
+                timestamp0[FORMAT_TIMESTAMP_MAX],
+                timestamp1[FORMAT_TIMESTAMP_MAX],
+                timestamp2[FORMAT_TIMESTAMP_MAX],
+                timestamp3[FORMAT_TIMESTAMP_MAX],
+                timestamp4[FORMAT_TIMESTAMP_MAX],
+                timespan[FORMAT_TIMESPAN_MAX];
+        Unit *following;
+        _cleanup_set_free_ Set *following_set = NULL;
+        const char *n;
+        CGroupMask m;
+        int r;
+
+        assert(u);
+        assert(u->type >= 0);
+
+        prefix = strempty(prefix);
+        prefix2 = strjoina(prefix, "\t");
+
+        fprintf(f,
+                "%s-> Unit %s:\n"
+                "%s\tDescription: %s\n"
+                "%s\tInstance: %s\n"
+                "%s\tUnit Load State: %s\n"
+                "%s\tUnit Active State: %s\n"
+                "%s\tState Change Timestamp: %s\n"
+                "%s\tInactive Exit Timestamp: %s\n"
+                "%s\tActive Enter Timestamp: %s\n"
+                "%s\tActive Exit Timestamp: %s\n"
+                "%s\tInactive Enter Timestamp: %s\n"
+                "%s\tMay GC: %s\n"
+                "%s\tNeed Daemon Reload: %s\n"
+                "%s\tTransient: %s\n"
+                "%s\tPerpetual: %s\n"
+                "%s\tGarbage Collection Mode: %s\n"
+                "%s\tSlice: %s\n"
+                "%s\tCGroup: %s\n"
+                "%s\tCGroup realized: %s\n",
+                prefix, u->id,
+                prefix, unit_description(u),
+                prefix, strna(u->instance),
+                prefix, unit_load_state_to_string(u->load_state),
+                prefix, unit_active_state_to_string(unit_active_state(u)),
+                prefix, strna(format_timestamp(timestamp0, sizeof(timestamp0), u->state_change_timestamp.realtime)),
+                prefix, strna(format_timestamp(timestamp1, sizeof(timestamp1), u->inactive_exit_timestamp.realtime)),
+                prefix, strna(format_timestamp(timestamp2, sizeof(timestamp2), u->active_enter_timestamp.realtime)),
+                prefix, strna(format_timestamp(timestamp3, sizeof(timestamp3), u->active_exit_timestamp.realtime)),
+                prefix, strna(format_timestamp(timestamp4, sizeof(timestamp4), u->inactive_enter_timestamp.realtime)),
+                prefix, yes_no(unit_may_gc(u)),
+                prefix, yes_no(unit_need_daemon_reload(u)),
+                prefix, yes_no(u->transient),
+                prefix, yes_no(u->perpetual),
+                prefix, collect_mode_to_string(u->collect_mode),
+                prefix, strna(unit_slice_name(u)),
+                prefix, strna(u->cgroup_path),
+                prefix, yes_no(u->cgroup_realized));
+
+        if (u->cgroup_realized_mask != 0) {
+                _cleanup_free_ char *s = NULL;
+                (void) cg_mask_to_string(u->cgroup_realized_mask, &s);
+                fprintf(f, "%s\tCGroup realized mask: %s\n", prefix, strnull(s));
+        }
+
+        if (u->cgroup_enabled_mask != 0) {
+                _cleanup_free_ char *s = NULL;
+                (void) cg_mask_to_string(u->cgroup_enabled_mask, &s);
+                fprintf(f, "%s\tCGroup enabled mask: %s\n", prefix, strnull(s));
+        }
+
+        m = unit_get_own_mask(u);
+        if (m != 0) {
+                _cleanup_free_ char *s = NULL;
+                (void) cg_mask_to_string(m, &s);
+                fprintf(f, "%s\tCGroup own mask: %s\n", prefix, strnull(s));
+        }
+
+        m = unit_get_members_mask(u);
+        if (m != 0) {
+                _cleanup_free_ char *s = NULL;
+                (void) cg_mask_to_string(m, &s);
+                fprintf(f, "%s\tCGroup members mask: %s\n", prefix, strnull(s));
+        }
+
+        m = unit_get_delegate_mask(u);
+        if (m != 0) {
+                _cleanup_free_ char *s = NULL;
+                (void) cg_mask_to_string(m, &s);
+                fprintf(f, "%s\tCGroup delegate mask: %s\n", prefix, strnull(s));
+        }
+
+        SET_FOREACH(t, u->names, i)
+                fprintf(f, "%s\tName: %s\n", prefix, t);
+
+        if (!sd_id128_is_null(u->invocation_id))
+                fprintf(f, "%s\tInvocation ID: " SD_ID128_FORMAT_STR "\n",
+                        prefix, SD_ID128_FORMAT_VAL(u->invocation_id));
+
+        STRV_FOREACH(j, u->documentation)
+                fprintf(f, "%s\tDocumentation: %s\n", prefix, *j);
+
+        following = unit_following(u);
+        if (following)
+                fprintf(f, "%s\tFollowing: %s\n", prefix, following->id);
+
+        r = unit_following_set(u, &following_set);
+        if (r >= 0) {
+                Unit *other;
+
+                SET_FOREACH(other, following_set, i)
+                        fprintf(f, "%s\tFollowing Set Member: %s\n", prefix, other->id);
+        }
+
+        if (u->fragment_path)
+                fprintf(f, "%s\tFragment Path: %s\n", prefix, u->fragment_path);
+
+        if (u->source_path)
+                fprintf(f, "%s\tSource Path: %s\n", prefix, u->source_path);
+
+        STRV_FOREACH(j, u->dropin_paths)
+                fprintf(f, "%s\tDropIn Path: %s\n", prefix, *j);
+
+        if (u->failure_action != EMERGENCY_ACTION_NONE)
+                fprintf(f, "%s\tFailure Action: %s\n", prefix, emergency_action_to_string(u->failure_action));
+        if (u->failure_action_exit_status >= 0)
+                fprintf(f, "%s\tFailure Action Exit Status: %i\n", prefix, u->failure_action_exit_status);
+        if (u->success_action != EMERGENCY_ACTION_NONE)
+                fprintf(f, "%s\tSuccess Action: %s\n", prefix, emergency_action_to_string(u->success_action));
+        if (u->success_action_exit_status >= 0)
+                fprintf(f, "%s\tSuccess Action Exit Status: %i\n", prefix, u->success_action_exit_status);
+
+        if (u->job_timeout != USEC_INFINITY)
+                fprintf(f, "%s\tJob Timeout: %s\n", prefix, format_timespan(timespan, sizeof(timespan), u->job_timeout, 0));
+
+        if (u->job_timeout_action != EMERGENCY_ACTION_NONE)
+                fprintf(f, "%s\tJob Timeout Action: %s\n", prefix, emergency_action_to_string(u->job_timeout_action));
+
+        if (u->job_timeout_reboot_arg)
+                fprintf(f, "%s\tJob Timeout Reboot Argument: %s\n", prefix, u->job_timeout_reboot_arg);
+
+        condition_dump_list(u->conditions, f, prefix, condition_type_to_string);
+        condition_dump_list(u->asserts, f, prefix, assert_type_to_string);
+
+        if (dual_timestamp_is_set(&u->condition_timestamp))
+                fprintf(f,
+                        "%s\tCondition Timestamp: %s\n"
+                        "%s\tCondition Result: %s\n",
+                        prefix, strna(format_timestamp(timestamp1, sizeof(timestamp1), u->condition_timestamp.realtime)),
+                        prefix, yes_no(u->condition_result));
+
+        if (dual_timestamp_is_set(&u->assert_timestamp))
+                fprintf(f,
+                        "%s\tAssert Timestamp: %s\n"
+                        "%s\tAssert Result: %s\n",
+                        prefix, strna(format_timestamp(timestamp1, sizeof(timestamp1), u->assert_timestamp.realtime)),
+                        prefix, yes_no(u->assert_result));
+
+        for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
+                UnitDependencyInfo di;
+                Unit *other;
+
+                HASHMAP_FOREACH_KEY(di.data, other, u->dependencies[d], i) {
+                        bool space = false;
+
+                        fprintf(f, "%s\t%s: %s (", prefix, unit_dependency_to_string(d), other->id);
+
+                        print_unit_dependency_mask(f, "origin", di.origin_mask, &space);
+                        print_unit_dependency_mask(f, "destination", di.destination_mask, &space);
+
+                        fputs(")\n", f);
+                }
+        }
+
+        if (!hashmap_isempty(u->requires_mounts_for)) {
+                UnitDependencyInfo di;
+                const char *path;
+
+                HASHMAP_FOREACH_KEY(di.data, path, u->requires_mounts_for, i) {
+                        bool space = false;
+
+                        fprintf(f, "%s\tRequiresMountsFor: %s (", prefix, path);
+
+                        print_unit_dependency_mask(f, "origin", di.origin_mask, &space);
+                        print_unit_dependency_mask(f, "destination", di.destination_mask, &space);
+
+                        fputs(")\n", f);
+                }
+        }
+
+        if (u->load_state == UNIT_LOADED) {
+
+                fprintf(f,
+                        "%s\tStopWhenUnneeded: %s\n"
+                        "%s\tRefuseManualStart: %s\n"
+                        "%s\tRefuseManualStop: %s\n"
+                        "%s\tDefaultDependencies: %s\n"
+                        "%s\tOnFailureJobMode: %s\n"
+                        "%s\tIgnoreOnIsolate: %s\n",
+                        prefix, yes_no(u->stop_when_unneeded),
+                        prefix, yes_no(u->refuse_manual_start),
+                        prefix, yes_no(u->refuse_manual_stop),
+                        prefix, yes_no(u->default_dependencies),
+                        prefix, job_mode_to_string(u->on_failure_job_mode),
+                        prefix, yes_no(u->ignore_on_isolate));
+
+                if (UNIT_VTABLE(u)->dump)
+                        UNIT_VTABLE(u)->dump(u, f, prefix2);
+
+        } else if (u->load_state == UNIT_MERGED)
+                fprintf(f,
+                        "%s\tMerged into: %s\n",
+                        prefix, u->merged_into->id);
+        else if (u->load_state == UNIT_ERROR)
+                fprintf(f, "%s\tLoad Error Code: %s\n", prefix, strerror(-u->load_error));
+
+        for (n = sd_bus_track_first(u->bus_track); n; n = sd_bus_track_next(u->bus_track))
+                fprintf(f, "%s\tBus Ref: %s\n", prefix, n);
+
+        if (u->job)
+                job_dump(u->job, f, prefix2);
+
+        if (u->nop_job)
+                job_dump(u->nop_job, f, prefix2);
+}
+
+/* Common implementation for multiple backends */
+int unit_load_fragment_and_dropin(Unit *u) {
+        int r;
+
+        assert(u);
+
+        /* Load a .{service,socket,...} file */
+        r = unit_load_fragment(u);
+        if (r < 0)
+                return r;
+
+        if (u->load_state == UNIT_STUB)
+                return -ENOENT;
+
+        /* Load drop-in directory data. If u is an alias, we might be reloading the
+         * target unit needlessly. But we cannot be sure which drops-ins have already
+         * been loaded and which not, at least without doing complicated book-keeping,
+         * so let's always reread all drop-ins. */
+        return unit_load_dropin(unit_follow_merge(u));
+}
+
+/* Common implementation for multiple backends */
+int unit_load_fragment_and_dropin_optional(Unit *u) {
+        int r;
+
+        assert(u);
+
+        /* Same as unit_load_fragment_and_dropin(), but whether
+         * something can be loaded or not doesn't matter. */
+
+        /* Load a .service/.socket/.slice/… file */
+        r = unit_load_fragment(u);
+        if (r < 0)
+                return r;
+
+        if (u->load_state == UNIT_STUB)
+                u->load_state = UNIT_LOADED;
+
+        /* Load drop-in directory data */
+        return unit_load_dropin(unit_follow_merge(u));
+}
+
+void unit_add_to_target_deps_queue(Unit *u) {
+        Manager *m = u->manager;
+
+        assert(u);
+
+        if (u->in_target_deps_queue)
+                return;
+
+        LIST_PREPEND(target_deps_queue, m->target_deps_queue, u);
+        u->in_target_deps_queue = true;
+}
+
+int unit_add_default_target_dependency(Unit *u, Unit *target) {
+        assert(u);
+        assert(target);
+
+        if (target->type != UNIT_TARGET)
+                return 0;
+
+        /* Only add the dependency if both units are loaded, so that
+         * that loop check below is reliable */
+        if (u->load_state != UNIT_LOADED ||
+            target->load_state != UNIT_LOADED)
+                return 0;
+
+        /* If either side wants no automatic dependencies, then let's
+         * skip this */
+        if (!u->default_dependencies ||
+            !target->default_dependencies)
+                return 0;
+
+        /* Don't create loops */
+        if (hashmap_get(target->dependencies[UNIT_BEFORE], u))
+                return 0;
+
+        return unit_add_dependency(target, UNIT_AFTER, u, true, UNIT_DEPENDENCY_DEFAULT);
+}
+
+static int unit_add_slice_dependencies(Unit *u) {
+        UnitDependencyMask mask;
+        assert(u);
+
+        if (!UNIT_HAS_CGROUP_CONTEXT(u))
+                return 0;
+
+        /* Slice units are implicitly ordered against their parent slices (as this relationship is encoded in the
+           name), while all other units are ordered based on configuration (as in their case Slice= configures the
+           relationship). */
+        mask = u->type == UNIT_SLICE ? UNIT_DEPENDENCY_IMPLICIT : UNIT_DEPENDENCY_FILE;
+
+        if (UNIT_ISSET(u->slice))
+                return unit_add_two_dependencies(u, UNIT_AFTER, UNIT_REQUIRES, UNIT_DEREF(u->slice), true, mask);
+
+        if (unit_has_name(u, SPECIAL_ROOT_SLICE))
+                return 0;
+
+        return unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_REQUIRES, SPECIAL_ROOT_SLICE, true, mask);
+}
+
+static int unit_add_mount_dependencies(Unit *u) {
+        UnitDependencyInfo di;
+        const char *path;
+        Iterator i;
+        int r;
+
+        assert(u);
+
+        HASHMAP_FOREACH_KEY(di.data, path, u->requires_mounts_for, i) {
+                char prefix[strlen(path) + 1];
+
+                PATH_FOREACH_PREFIX_MORE(prefix, path) {
+                        _cleanup_free_ char *p = NULL;
+                        Unit *m;
+
+                        r = unit_name_from_path(prefix, ".mount", &p);
+                        if (r < 0)
+                                return r;
+
+                        m = manager_get_unit(u->manager, p);
+                        if (!m) {
+                                /* Make sure to load the mount unit if
+                                 * it exists. If so the dependencies
+                                 * on this unit will be added later
+                                 * during the loading of the mount
+                                 * unit. */
+                                (void) manager_load_unit_prepare(u->manager, p, NULL, NULL, &m);
+                                continue;
+                        }
+                        if (m == u)
+                                continue;
+
+                        if (m->load_state != UNIT_LOADED)
+                                continue;
+
+                        r = unit_add_dependency(u, UNIT_AFTER, m, true, di.origin_mask);
+                        if (r < 0)
+                                return r;
+
+                        if (m->fragment_path) {
+                                r = unit_add_dependency(u, UNIT_REQUIRES, m, true, di.origin_mask);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+        }
+
+        return 0;
+}
+
+static int unit_add_startup_units(Unit *u) {
+        CGroupContext *c;
+        int r;
+
+        c = unit_get_cgroup_context(u);
+        if (!c)
+                return 0;
+
+        if (c->startup_cpu_shares == CGROUP_CPU_SHARES_INVALID &&
+            c->startup_io_weight == CGROUP_WEIGHT_INVALID &&
+            c->startup_blockio_weight == CGROUP_BLKIO_WEIGHT_INVALID)
+                return 0;
+
+        r = set_ensure_allocated(&u->manager->startup_units, NULL);
+        if (r < 0)
+                return r;
+
+        return set_put(u->manager->startup_units, u);
+}
+
+int unit_load(Unit *u) {
+        int r;
+
+        assert(u);
+
+        if (u->in_load_queue) {
+                LIST_REMOVE(load_queue, u->manager->load_queue, u);
+                u->in_load_queue = false;
+        }
+
+        if (u->type == _UNIT_TYPE_INVALID)
+                return -EINVAL;
+
+        if (u->load_state != UNIT_STUB)
+                return 0;
+
+        if (u->transient_file) {
+                /* Finalize transient file: if this is a transient unit file, as soon as we reach unit_load() the setup
+                 * is complete, hence let's synchronize the unit file we just wrote to disk. */
+
+                r = fflush_and_check(u->transient_file);
+                if (r < 0)
+                        goto fail;
+
+                u->transient_file = safe_fclose(u->transient_file);
+                u->fragment_mtime = now(CLOCK_REALTIME);
+        }
+
+        if (UNIT_VTABLE(u)->load) {
+                r = UNIT_VTABLE(u)->load(u);
+                if (r < 0)
+                        goto fail;
+        }
+
+        if (u->load_state == UNIT_STUB) {
+                r = -ENOENT;
+                goto fail;
+        }
+
+        if (u->load_state == UNIT_LOADED) {
+                unit_add_to_target_deps_queue(u);
+
+                r = unit_add_slice_dependencies(u);
+                if (r < 0)
+                        goto fail;
+
+                r = unit_add_mount_dependencies(u);
+                if (r < 0)
+                        goto fail;
+
+                r = unit_add_startup_units(u);
+                if (r < 0)
+                        goto fail;
+
+                if (u->on_failure_job_mode == JOB_ISOLATE && hashmap_size(u->dependencies[UNIT_ON_FAILURE]) > 1) {
+                        log_unit_error(u, "More than one OnFailure= dependencies specified but OnFailureJobMode=isolate set. Refusing.");
+                        r = -ENOEXEC;
+                        goto fail;
+                }
+
+                if (u->job_running_timeout != USEC_INFINITY && u->job_running_timeout > u->job_timeout)
+                        log_unit_warning(u, "JobRunningTimeoutSec= is greater than JobTimeoutSec=, it has no effect.");
+
+                /* We finished loading, let's ensure our parents recalculate the members mask */
+                unit_invalidate_cgroup_members_masks(u);
+        }
+
+        assert((u->load_state != UNIT_MERGED) == !u->merged_into);
+
+        unit_add_to_dbus_queue(unit_follow_merge(u));
+        unit_add_to_gc_queue(u);
+
+        return 0;
+
+fail:
+        /* We convert ENOEXEC errors to the UNIT_BAD_SETTING load state here. Configuration parsing code should hence
+         * return ENOEXEC to ensure units are placed in this state after loading */
+
+        u->load_state = u->load_state == UNIT_STUB ? UNIT_NOT_FOUND :
+                                     r == -ENOEXEC ? UNIT_BAD_SETTING :
+                                                     UNIT_ERROR;
+        u->load_error = r;
+
+        unit_add_to_dbus_queue(u);
+        unit_add_to_gc_queue(u);
+
+        return log_unit_debug_errno(u, r, "Failed to load configuration: %m");
+}
+
+static bool unit_condition_test_list(Unit *u, Condition *first, const char *(*to_string)(ConditionType t)) {
+        Condition *c;
+        int triggered = -1;
+
+        assert(u);
+        assert(to_string);
+
+        /* If the condition list is empty, then it is true */
+        if (!first)
+                return true;
+
+        /* Otherwise, if all of the non-trigger conditions apply and
+         * if any of the trigger conditions apply (unless there are
+         * none) we return true */
+        LIST_FOREACH(conditions, c, first) {
+                int r;
+
+                r = condition_test(c);
+                if (r < 0)
+                        log_unit_warning(u,
+                                         "Couldn't determine result for %s=%s%s%s, assuming failed: %m",
+                                         to_string(c->type),
+                                         c->trigger ? "|" : "",
+                                         c->negate ? "!" : "",
+                                         c->parameter);
+                else
+                        log_unit_debug(u,
+                                       "%s=%s%s%s %s.",
+                                       to_string(c->type),
+                                       c->trigger ? "|" : "",
+                                       c->negate ? "!" : "",
+                                       c->parameter,
+                                       condition_result_to_string(c->result));
+
+                if (!c->trigger && r <= 0)
+                        return false;
+
+                if (c->trigger && triggered <= 0)
+                        triggered = r > 0;
+        }
+
+        return triggered != 0;
+}
+
+static bool unit_condition_test(Unit *u) {
+        assert(u);
+
+        dual_timestamp_get(&u->condition_timestamp);
+        u->condition_result = unit_condition_test_list(u, u->conditions, condition_type_to_string);
+
+        unit_add_to_dbus_queue(u);
+
+        return u->condition_result;
+}
+
+static bool unit_assert_test(Unit *u) {
+        assert(u);
+
+        dual_timestamp_get(&u->assert_timestamp);
+        u->assert_result = unit_condition_test_list(u, u->asserts, assert_type_to_string);
+
+        unit_add_to_dbus_queue(u);
+
+        return u->assert_result;
+}
+
+void unit_status_printf(Unit *u, const char *status, const char *unit_status_msg_format) {
+        const char *d;
+
+        d = unit_description(u);
+        if (log_get_show_color())
+                d = strjoina(ANSI_HIGHLIGHT, d, ANSI_NORMAL);
+
+        DISABLE_WARNING_FORMAT_NONLITERAL;
+        manager_status_printf(u->manager, STATUS_TYPE_NORMAL, status, unit_status_msg_format, d);
+        REENABLE_WARNING;
+}
+
+int unit_start_limit_test(Unit *u) {
+        const char *reason;
+
+        assert(u);
+
+        if (ratelimit_below(&u->start_limit)) {
+                u->start_limit_hit = false;
+                return 0;
+        }
+
+        log_unit_warning(u, "Start request repeated too quickly.");
+        u->start_limit_hit = true;
+
+        reason = strjoina("unit ", u->id, " failed");
+
+        return emergency_action(u->manager, u->start_limit_action,
+                                EMERGENCY_ACTION_IS_WATCHDOG|EMERGENCY_ACTION_WARN,
+                                u->reboot_arg, -1, reason);
+}
+
+bool unit_shall_confirm_spawn(Unit *u) {
+        assert(u);
+
+        if (manager_is_confirm_spawn_disabled(u->manager))
+                return false;
+
+        /* For some reasons units remaining in the same process group
+         * as PID 1 fail to acquire the console even if it's not used
+         * by any process. So skip the confirmation question for them. */
+        return !unit_get_exec_context(u)->same_pgrp;
+}
+
+static bool unit_verify_deps(Unit *u) {
+        Unit *other;
+        Iterator j;
+        void *v;
+
+        assert(u);
+
+        /* Checks whether all BindsTo= dependencies of this unit are fulfilled — if they are also combined with
+         * After=. We do not check Requires= or Requisite= here as they only should have an effect on the job
+         * processing, but do not have any effect afterwards. We don't check BindsTo= dependencies that are not used in
+         * conjunction with After= as for them any such check would make things entirely racy. */
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_BINDS_TO], j) {
+
+                if (!hashmap_contains(u->dependencies[UNIT_AFTER], other))
+                        continue;
+
+                if (!UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(other))) {
+                        log_unit_notice(u, "Bound to unit %s, but unit isn't active.", other->id);
+                        return false;
+                }
+        }
+
+        return true;
+}
+
+/* Errors:
+ *         -EBADR:      This unit type does not support starting.
+ *         -EALREADY:   Unit is already started.
+ *         -EAGAIN:     An operation is already in progress. Retry later.
+ *         -ECANCELED:  Too many requests for now.
+ *         -EPROTO:     Assert failed
+ *         -EINVAL:     Unit not loaded
+ *         -EOPNOTSUPP: Unit type not supported
+ *         -ENOLINK:    The necessary dependencies are not fulfilled.
+ *         -ESTALE:     This unit has been started before and can't be started a second time
+ */
+int unit_start(Unit *u) {
+        UnitActiveState state;
+        Unit *following;
+
+        assert(u);
+
+        /* If this is already started, then this will succeed. Note
+         * that this will even succeed if this unit is not startable
+         * by the user. This is relied on to detect when we need to
+         * wait for units and when waiting is finished. */
+        state = unit_active_state(u);
+        if (UNIT_IS_ACTIVE_OR_RELOADING(state))
+                return -EALREADY;
+
+        /* Units that aren't loaded cannot be started */
+        if (u->load_state != UNIT_LOADED)
+                return -EINVAL;
+
+        /* Refuse starting scope units more than once */
+        if (UNIT_VTABLE(u)->once_only && dual_timestamp_is_set(&u->inactive_enter_timestamp))
+                return -ESTALE;
+
+        /* If the conditions failed, don't do anything at all. If we
+         * already are activating this call might still be useful to
+         * speed up activation in case there is some hold-off time,
+         * but we don't want to recheck the condition in that case. */
+        if (state != UNIT_ACTIVATING &&
+            !unit_condition_test(u)) {
+                log_unit_debug(u, "Starting requested but condition failed. Not starting unit.");
+                return -ECOMM;
+        }
+
+        /* If the asserts failed, fail the entire job */
+        if (state != UNIT_ACTIVATING &&
+            !unit_assert_test(u)) {
+                log_unit_notice(u, "Starting requested but asserts failed.");
+                return -EPROTO;
+        }
+
+        /* Units of types that aren't supported cannot be
+         * started. Note that we do this test only after the condition
+         * checks, so that we rather return condition check errors
+         * (which are usually not considered a true failure) than "not
+         * supported" errors (which are considered a failure).
+         */
+        if (!unit_supported(u))
+                return -EOPNOTSUPP;
+
+        /* Let's make sure that the deps really are in order before we start this. Normally the job engine should have
+         * taken care of this already, but let's check this here again. After all, our dependencies might not be in
+         * effect anymore, due to a reload or due to a failed condition. */
+        if (!unit_verify_deps(u))
+                return -ENOLINK;
+
+        /* Forward to the main object, if we aren't it. */
+        following = unit_following(u);
+        if (following) {
+                log_unit_debug(u, "Redirecting start request from %s to %s.", u->id, following->id);
+                return unit_start(following);
+        }
+
+        /* If it is stopped, but we cannot start it, then fail */
+        if (!UNIT_VTABLE(u)->start)
+                return -EBADR;
+
+        /* We don't suppress calls to ->start() here when we are
+         * already starting, to allow this request to be used as a
+         * "hurry up" call, for example when the unit is in some "auto
+         * restart" state where it waits for a holdoff timer to elapse
+         * before it will start again. */
+
+        unit_add_to_dbus_queue(u);
+
+        return UNIT_VTABLE(u)->start(u);
+}
+
+bool unit_can_start(Unit *u) {
+        assert(u);
+
+        if (u->load_state != UNIT_LOADED)
+                return false;
+
+        if (!unit_supported(u))
+                return false;
+
+        /* Scope units may be started only once */
+        if (UNIT_VTABLE(u)->once_only && dual_timestamp_is_set(&u->inactive_exit_timestamp))
+                return false;
+
+        return !!UNIT_VTABLE(u)->start;
+}
+
+bool unit_can_isolate(Unit *u) {
+        assert(u);
+
+        return unit_can_start(u) &&
+                u->allow_isolate;
+}
+
+/* Errors:
+ *         -EBADR:    This unit type does not support stopping.
+ *         -EALREADY: Unit is already stopped.
+ *         -EAGAIN:   An operation is already in progress. Retry later.
+ */
+int unit_stop(Unit *u) {
+        UnitActiveState state;
+        Unit *following;
+
+        assert(u);
+
+        state = unit_active_state(u);
+        if (UNIT_IS_INACTIVE_OR_FAILED(state))
+                return -EALREADY;
+
+        following = unit_following(u);
+        if (following) {
+                log_unit_debug(u, "Redirecting stop request from %s to %s.", u->id, following->id);
+                return unit_stop(following);
+        }
+
+        if (!UNIT_VTABLE(u)->stop)
+                return -EBADR;
+
+        unit_add_to_dbus_queue(u);
+
+        return UNIT_VTABLE(u)->stop(u);
+}
+
+bool unit_can_stop(Unit *u) {
+        assert(u);
+
+        if (!unit_supported(u))
+                return false;
+
+        if (u->perpetual)
+                return false;
+
+        return !!UNIT_VTABLE(u)->stop;
+}
+
+/* Errors:
+ *         -EBADR:    This unit type does not support reloading.
+ *         -ENOEXEC:  Unit is not started.
+ *         -EAGAIN:   An operation is already in progress. Retry later.
+ */
+int unit_reload(Unit *u) {
+        UnitActiveState state;
+        Unit *following;
+
+        assert(u);
+
+        if (u->load_state != UNIT_LOADED)
+                return -EINVAL;
+
+        if (!unit_can_reload(u))
+                return -EBADR;
+
+        state = unit_active_state(u);
+        if (state == UNIT_RELOADING)
+                return -EALREADY;
+
+        if (state != UNIT_ACTIVE) {
+                log_unit_warning(u, "Unit cannot be reloaded because it is inactive.");
+                return -ENOEXEC;
+        }
+
+        following = unit_following(u);
+        if (following) {
+                log_unit_debug(u, "Redirecting reload request from %s to %s.", u->id, following->id);
+                return unit_reload(following);
+        }
+
+        unit_add_to_dbus_queue(u);
+
+        if (!UNIT_VTABLE(u)->reload) {
+                /* Unit doesn't have a reload function, but we need to propagate the reload anyway */
+                unit_notify(u, unit_active_state(u), unit_active_state(u), 0);
+                return 0;
+        }
+
+        return UNIT_VTABLE(u)->reload(u);
+}
+
+bool unit_can_reload(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->can_reload)
+                return UNIT_VTABLE(u)->can_reload(u);
+
+        if (!hashmap_isempty(u->dependencies[UNIT_PROPAGATES_RELOAD_TO]))
+                return true;
+
+        return UNIT_VTABLE(u)->reload;
+}
+
+bool unit_is_unneeded(Unit *u) {
+        static const UnitDependency deps[] = {
+                UNIT_REQUIRED_BY,
+                UNIT_REQUISITE_OF,
+                UNIT_WANTED_BY,
+                UNIT_BOUND_BY,
+        };
+        size_t j;
+
+        assert(u);
+
+        if (!u->stop_when_unneeded)
+                return false;
+
+        /* Don't clean up while the unit is transitioning or is even inactive. */
+        if (!UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u)))
+                return false;
+        if (u->job)
+                return false;
+
+        for (j = 0; j < ELEMENTSOF(deps); j++) {
+                Unit *other;
+                Iterator i;
+                void *v;
+
+                /* If a dependent unit has a job queued, is active or transitioning, or is marked for
+                 * restart, then don't clean this one up. */
+
+                HASHMAP_FOREACH_KEY(v, other, u->dependencies[deps[j]], i) {
+                        if (other->job)
+                                return false;
+
+                        if (!UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other)))
+                                return false;
+
+                        if (unit_will_restart(other))
+                                return false;
+                }
+        }
+
+        return true;
+}
+
+static void check_unneeded_dependencies(Unit *u) {
+
+        static const UnitDependency deps[] = {
+                UNIT_REQUIRES,
+                UNIT_REQUISITE,
+                UNIT_WANTS,
+                UNIT_BINDS_TO,
+        };
+        size_t j;
+
+        assert(u);
+
+        /* Add all units this unit depends on to the queue that processes StopWhenUnneeded= behaviour. */
+
+        for (j = 0; j < ELEMENTSOF(deps); j++) {
+                Unit *other;
+                Iterator i;
+                void *v;
+
+                HASHMAP_FOREACH_KEY(v, other, u->dependencies[deps[j]], i)
+                        unit_submit_to_stop_when_unneeded_queue(other);
+        }
+}
+
+static void unit_check_binds_to(Unit *u) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        bool stop = false;
+        Unit *other;
+        Iterator i;
+        void *v;
+        int r;
+
+        assert(u);
+
+        if (u->job)
+                return;
+
+        if (unit_active_state(u) != UNIT_ACTIVE)
+                return;
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_BINDS_TO], i) {
+                if (other->job)
+                        continue;
+
+                if (!other->coldplugged)
+                        /* We might yet create a job for the other unit… */
+                        continue;
+
+                if (!UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other)))
+                        continue;
+
+                stop = true;
+                break;
+        }
+
+        if (!stop)
+                return;
+
+        /* If stopping a unit fails continuously we might enter a stop
+         * loop here, hence stop acting on the service being
+         * unnecessary after a while. */
+        if (!ratelimit_below(&u->auto_stop_ratelimit)) {
+                log_unit_warning(u, "Unit is bound to inactive unit %s, but not stopping since we tried this too often recently.", other->id);
+                return;
+        }
+
+        assert(other);
+        log_unit_info(u, "Unit is bound to inactive unit %s. Stopping, too.", other->id);
+
+        /* A unit we need to run is gone. Sniff. Let's stop this. */
+        r = manager_add_job(u->manager, JOB_STOP, u, JOB_FAIL, &error, NULL);
+        if (r < 0)
+                log_unit_warning_errno(u, r, "Failed to enqueue stop job, ignoring: %s", bus_error_message(&error, r));
+}
+
+static void retroactively_start_dependencies(Unit *u) {
+        Iterator i;
+        Unit *other;
+        void *v;
+
+        assert(u);
+        assert(UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u)));
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_REQUIRES], i)
+                if (!hashmap_get(u->dependencies[UNIT_AFTER], other) &&
+                    !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_START, other, JOB_REPLACE, NULL, NULL);
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_BINDS_TO], i)
+                if (!hashmap_get(u->dependencies[UNIT_AFTER], other) &&
+                    !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_START, other, JOB_REPLACE, NULL, NULL);
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_WANTS], i)
+                if (!hashmap_get(u->dependencies[UNIT_AFTER], other) &&
+                    !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_START, other, JOB_FAIL, NULL, NULL);
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_CONFLICTS], i)
+                if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_STOP, other, JOB_REPLACE, NULL, NULL);
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_CONFLICTED_BY], i)
+                if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_STOP, other, JOB_REPLACE, NULL, NULL);
+}
+
+static void retroactively_stop_dependencies(Unit *u) {
+        Unit *other;
+        Iterator i;
+        void *v;
+
+        assert(u);
+        assert(UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(u)));
+
+        /* Pull down units which are bound to us recursively if enabled */
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_BOUND_BY], i)
+                if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
+                        manager_add_job(u->manager, JOB_STOP, other, JOB_REPLACE, NULL, NULL);
+}
+
+void unit_start_on_failure(Unit *u) {
+        Unit *other;
+        Iterator i;
+        void *v;
+        int r;
+
+        assert(u);
+
+        if (hashmap_size(u->dependencies[UNIT_ON_FAILURE]) <= 0)
+                return;
+
+        log_unit_info(u, "Triggering OnFailure= dependencies.");
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_ON_FAILURE], i) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+
+                r = manager_add_job(u->manager, JOB_START, other, u->on_failure_job_mode, &error, NULL);
+                if (r < 0)
+                        log_unit_warning_errno(u, r, "Failed to enqueue OnFailure= job, ignoring: %s", bus_error_message(&error, r));
+        }
+}
+
+void unit_trigger_notify(Unit *u) {
+        Unit *other;
+        Iterator i;
+        void *v;
+
+        assert(u);
+
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_TRIGGERED_BY], i)
+                if (UNIT_VTABLE(other)->trigger_notify)
+                        UNIT_VTABLE(other)->trigger_notify(other, u);
+}
+
+static int unit_log_resources(Unit *u) {
+        struct iovec iovec[1 + _CGROUP_IP_ACCOUNTING_METRIC_MAX + 4];
+        bool any_traffic = false, have_ip_accounting = false;
+        _cleanup_free_ char *igress = NULL, *egress = NULL;
+        size_t n_message_parts = 0, n_iovec = 0;
+        char* message_parts[3 + 1], *t;
+        nsec_t nsec = NSEC_INFINITY;
+        CGroupIPAccountingMetric m;
+        size_t i;
+        int r;
+        const char* const ip_fields[_CGROUP_IP_ACCOUNTING_METRIC_MAX] = {
+                [CGROUP_IP_INGRESS_BYTES]   = "IP_METRIC_INGRESS_BYTES",
+                [CGROUP_IP_INGRESS_PACKETS] = "IP_METRIC_INGRESS_PACKETS",
+                [CGROUP_IP_EGRESS_BYTES]    = "IP_METRIC_EGRESS_BYTES",
+                [CGROUP_IP_EGRESS_PACKETS]  = "IP_METRIC_EGRESS_PACKETS",
+        };
+
+        assert(u);
+
+        /* Invoked whenever a unit enters failed or dead state. Logs information about consumed resources if resource
+         * accounting was enabled for a unit. It does this in two ways: a friendly human readable string with reduced
+         * information and the complete data in structured fields. */
+
+        (void) unit_get_cpu_usage(u, &nsec);
+        if (nsec != NSEC_INFINITY) {
+                char buf[FORMAT_TIMESPAN_MAX] = "";
+
+                /* Format the CPU time for inclusion in the structured log message */
+                if (asprintf(&t, "CPU_USAGE_NSEC=%" PRIu64, nsec) < 0) {
+                        r = log_oom();
+                        goto finish;
+                }
+                iovec[n_iovec++] = IOVEC_MAKE_STRING(t);
+
+                /* Format the CPU time for inclusion in the human language message string */
+                format_timespan(buf, sizeof(buf), nsec / NSEC_PER_USEC, USEC_PER_MSEC);
+                t = strjoin("consumed ", buf, " CPU time");
+                if (!t) {
+                        r = log_oom();
+                        goto finish;
+                }
+
+                message_parts[n_message_parts++] = t;
+        }
+
+        for (m = 0; m < _CGROUP_IP_ACCOUNTING_METRIC_MAX; m++) {
+                char buf[FORMAT_BYTES_MAX] = "";
+                uint64_t value = UINT64_MAX;
+
+                assert(ip_fields[m]);
+
+                (void) unit_get_ip_accounting(u, m, &value);
+                if (value == UINT64_MAX)
+                        continue;
+
+                have_ip_accounting = true;
+                if (value > 0)
+                        any_traffic = true;
+
+                /* Format IP accounting data for inclusion in the structured log message */
+                if (asprintf(&t, "%s=%" PRIu64, ip_fields[m], value) < 0) {
+                        r = log_oom();
+                        goto finish;
+                }
+                iovec[n_iovec++] = IOVEC_MAKE_STRING(t);
+
+                /* Format the IP accounting data for inclusion in the human language message string, but only for the
+                 * bytes counters (and not for the packets counters) */
+                if (m == CGROUP_IP_INGRESS_BYTES) {
+                        assert(!igress);
+                        igress = strjoin("received ", format_bytes(buf, sizeof(buf), value), " IP traffic");
+                        if (!igress) {
+                                r = log_oom();
+                                goto finish;
+                        }
+                } else if (m == CGROUP_IP_EGRESS_BYTES) {
+                        assert(!egress);
+                        egress = strjoin("sent ", format_bytes(buf, sizeof(buf), value), " IP traffic");
+                        if (!egress) {
+                                r = log_oom();
+                                goto finish;
+                        }
+                }
+        }
+
+        if (have_ip_accounting) {
+                if (any_traffic) {
+                        if (igress)
+                                message_parts[n_message_parts++] = TAKE_PTR(igress);
+                        if (egress)
+                                message_parts[n_message_parts++] = TAKE_PTR(egress);
+
+                } else {
+                        char *k;
+
+                        k = strdup("no IP traffic");
+                        if (!k) {
+                                r = log_oom();
+                                goto finish;
+                        }
+
+                        message_parts[n_message_parts++] = k;
+                }
+        }
+
+        /* Is there any accounting data available at all? */
+        if (n_iovec == 0) {
+                r = 0;
+                goto finish;
+        }
+
+        if (n_message_parts == 0)
+                t = strjoina("MESSAGE=", u->id, ": Completed.");
+        else {
+                _cleanup_free_ char *joined;
+
+                message_parts[n_message_parts] = NULL;
+
+                joined = strv_join(message_parts, ", ");
+                if (!joined) {
+                        r = log_oom();
+                        goto finish;
+                }
+
+                joined[0] = ascii_toupper(joined[0]);
+                t = strjoina("MESSAGE=", u->id, ": ", joined, ".");
+        }
+
+        /* The following four fields we allocate on the stack or are static strings, we hence don't want to free them,
+         * and hence don't increase n_iovec for them */
+        iovec[n_iovec] = IOVEC_MAKE_STRING(t);
+        iovec[n_iovec + 1] = IOVEC_MAKE_STRING("MESSAGE_ID=" SD_MESSAGE_UNIT_RESOURCES_STR);
+
+        t = strjoina(u->manager->unit_log_field, u->id);
+        iovec[n_iovec + 2] = IOVEC_MAKE_STRING(t);
+
+        t = strjoina(u->manager->invocation_log_field, u->invocation_id_string);
+        iovec[n_iovec + 3] = IOVEC_MAKE_STRING(t);
+
+        log_struct_iovec(LOG_INFO, iovec, n_iovec + 4);
+        r = 0;
+
+finish:
+        for (i = 0; i < n_message_parts; i++)
+                free(message_parts[i]);
+
+        for (i = 0; i < n_iovec; i++)
+                free(iovec[i].iov_base);
+
+        return r;
+
+}
+
+static void unit_update_on_console(Unit *u) {
+        bool b;
+
+        assert(u);
+
+        b = unit_needs_console(u);
+        if (u->on_console == b)
+                return;
+
+        u->on_console = b;
+        if (b)
+                manager_ref_console(u->manager);
+        else
+                manager_unref_console(u->manager);
+}
+
+static void unit_emit_audit_start(Unit *u) {
+        assert(u);
+
+        if (u->type != UNIT_SERVICE)
+                return;
+
+        /* Write audit record if we have just finished starting up */
+        manager_send_unit_audit(u->manager, u, AUDIT_SERVICE_START, true);
+        u->in_audit = true;
+}
+
+static void unit_emit_audit_stop(Unit *u, UnitActiveState state) {
+        assert(u);
+
+        if (u->type != UNIT_SERVICE)
+                return;
+
+        if (u->in_audit) {
+                /* Write audit record if we have just finished shutting down */
+                manager_send_unit_audit(u->manager, u, AUDIT_SERVICE_STOP, state == UNIT_INACTIVE);
+                u->in_audit = false;
+        } else {
+                /* Hmm, if there was no start record written write it now, so that we always have a nice pair */
+                manager_send_unit_audit(u->manager, u, AUDIT_SERVICE_START, state == UNIT_INACTIVE);
+
+                if (state == UNIT_INACTIVE)
+                        manager_send_unit_audit(u->manager, u, AUDIT_SERVICE_STOP, true);
+        }
+}
+
+static bool unit_process_job(Job *j, UnitActiveState ns, UnitNotifyFlags flags) {
+        bool unexpected = false;
+
+        assert(j);
+
+        if (j->state == JOB_WAITING)
+
+                /* So we reached a different state for this job. Let's see if we can run it now if it failed previously
+                 * due to EAGAIN. */
+                job_add_to_run_queue(j);
+
+        /* Let's check whether the unit's new state constitutes a finished job, or maybe contradicts a running job and
+         * hence needs to invalidate jobs. */
+
+        switch (j->type) {
+
+        case JOB_START:
+        case JOB_VERIFY_ACTIVE:
+
+                if (UNIT_IS_ACTIVE_OR_RELOADING(ns))
+                        job_finish_and_invalidate(j, JOB_DONE, true, false);
+                else if (j->state == JOB_RUNNING && ns != UNIT_ACTIVATING) {
+                        unexpected = true;
+
+                        if (UNIT_IS_INACTIVE_OR_FAILED(ns))
+                                job_finish_and_invalidate(j, ns == UNIT_FAILED ? JOB_FAILED : JOB_DONE, true, false);
+                }
+
+                break;
+
+        case JOB_RELOAD:
+        case JOB_RELOAD_OR_START:
+        case JOB_TRY_RELOAD:
+
+                if (j->state == JOB_RUNNING) {
+                        if (ns == UNIT_ACTIVE)
+                                job_finish_and_invalidate(j, (flags & UNIT_NOTIFY_RELOAD_FAILURE) ? JOB_FAILED : JOB_DONE, true, false);
+                        else if (!IN_SET(ns, UNIT_ACTIVATING, UNIT_RELOADING)) {
+                                unexpected = true;
+
+                                if (UNIT_IS_INACTIVE_OR_FAILED(ns))
+                                        job_finish_and_invalidate(j, ns == UNIT_FAILED ? JOB_FAILED : JOB_DONE, true, false);
+                        }
+                }
+
+                break;
+
+        case JOB_STOP:
+        case JOB_RESTART:
+        case JOB_TRY_RESTART:
+
+                if (UNIT_IS_INACTIVE_OR_FAILED(ns))
+                        job_finish_and_invalidate(j, JOB_DONE, true, false);
+                else if (j->state == JOB_RUNNING && ns != UNIT_DEACTIVATING) {
+                        unexpected = true;
+                        job_finish_and_invalidate(j, JOB_FAILED, true, false);
+                }
+
+                break;
+
+        default:
+                assert_not_reached("Job type unknown");
+        }
+
+        return unexpected;
+}
+
+void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, UnitNotifyFlags flags) {
+        const char *reason;
+        Manager *m;
+
+        assert(u);
+        assert(os < _UNIT_ACTIVE_STATE_MAX);
+        assert(ns < _UNIT_ACTIVE_STATE_MAX);
+
+        /* Note that this is called for all low-level state changes, even if they might map to the same high-level
+         * UnitActiveState! That means that ns == os is an expected behavior here. For example: if a mount point is
+         * remounted this function will be called too! */
+
+        m = u->manager;
+
+        /* Let's enqueue the change signal early. In case this unit has a job associated we want that this unit is in
+         * the bus queue, so that any job change signal queued will force out the unit change signal first. */
+        unit_add_to_dbus_queue(u);
+
+        /* Update timestamps for state changes */
+        if (!MANAGER_IS_RELOADING(m)) {
+                dual_timestamp_get(&u->state_change_timestamp);
+
+                if (UNIT_IS_INACTIVE_OR_FAILED(os) && !UNIT_IS_INACTIVE_OR_FAILED(ns))
+                        u->inactive_exit_timestamp = u->state_change_timestamp;
+                else if (!UNIT_IS_INACTIVE_OR_FAILED(os) && UNIT_IS_INACTIVE_OR_FAILED(ns))
+                        u->inactive_enter_timestamp = u->state_change_timestamp;
+
+                if (!UNIT_IS_ACTIVE_OR_RELOADING(os) && UNIT_IS_ACTIVE_OR_RELOADING(ns))
+                        u->active_enter_timestamp = u->state_change_timestamp;
+                else if (UNIT_IS_ACTIVE_OR_RELOADING(os) && !UNIT_IS_ACTIVE_OR_RELOADING(ns))
+                        u->active_exit_timestamp = u->state_change_timestamp;
+        }
+
+        /* Keep track of failed units */
+        (void) manager_update_failed_units(m, u, ns == UNIT_FAILED);
+
+        /* Make sure the cgroup and state files are always removed when we become inactive */
+        if (UNIT_IS_INACTIVE_OR_FAILED(ns)) {
+                unit_prune_cgroup(u);
+                unit_unlink_state_files(u);
+        }
+
+        unit_update_on_console(u);
+
+        if (!MANAGER_IS_RELOADING(m)) {
+                bool unexpected;
+
+                /* Let's propagate state changes to the job */
+                if (u->job)
+                        unexpected = unit_process_job(u->job, ns, flags);
+                else
+                        unexpected = true;
+
+                /* If this state change happened without being requested by a job, then let's retroactively start or
+                 * stop dependencies. We skip that step when deserializing, since we don't want to create any
+                 * additional jobs just because something is already activated. */
+
+                if (unexpected) {
+                        if (UNIT_IS_INACTIVE_OR_FAILED(os) && UNIT_IS_ACTIVE_OR_ACTIVATING(ns))
+                                retroactively_start_dependencies(u);
+                        else if (UNIT_IS_ACTIVE_OR_ACTIVATING(os) && UNIT_IS_INACTIVE_OR_DEACTIVATING(ns))
+                                retroactively_stop_dependencies(u);
+                }
+
+                /* stop unneeded units regardless if going down was expected or not */
+                if (UNIT_IS_INACTIVE_OR_FAILED(ns))
+                        check_unneeded_dependencies(u);
+
+                if (ns != os && ns == UNIT_FAILED) {
+                        log_unit_debug(u, "Unit entered failed state.");
+
+                        if (!(flags & UNIT_NOTIFY_WILL_AUTO_RESTART))
+                                unit_start_on_failure(u);
+                }
+
+                if (UNIT_IS_ACTIVE_OR_RELOADING(ns) && !UNIT_IS_ACTIVE_OR_RELOADING(os)) {
+                        /* This unit just finished starting up */
+
+                        unit_emit_audit_start(u);
+                        manager_send_unit_plymouth(m, u);
+                }
+
+                if (UNIT_IS_INACTIVE_OR_FAILED(ns) && !UNIT_IS_INACTIVE_OR_FAILED(os)) {
+                        /* This unit just stopped/failed. */
+
+                        unit_emit_audit_stop(u, ns);
+                        unit_log_resources(u);
+                }
+        }
+
+        manager_recheck_journal(m);
+        manager_recheck_dbus(m);
+
+        unit_trigger_notify(u);
+
+        if (!MANAGER_IS_RELOADING(m)) {
+                /* Maybe we finished startup and are now ready for being stopped because unneeded? */
+                unit_submit_to_stop_when_unneeded_queue(u);
+
+                /* Maybe we finished startup, but something we needed has vanished? Let's die then. (This happens when
+                 * something BindsTo= to a Type=oneshot unit, as these units go directly from starting to inactive,
+                 * without ever entering started.) */
+                unit_check_binds_to(u);
+
+                if (os != UNIT_FAILED && ns == UNIT_FAILED) {
+                        reason = strjoina("unit ", u->id, " failed");
+                        (void) emergency_action(m, u->failure_action, 0, u->reboot_arg, unit_failure_action_exit_status(u), reason);
+                } else if (!UNIT_IS_INACTIVE_OR_FAILED(os) && ns == UNIT_INACTIVE) {
+                        reason = strjoina("unit ", u->id, " succeeded");
+                        (void) emergency_action(m, u->success_action, 0, u->reboot_arg, unit_success_action_exit_status(u), reason);
+                }
+        }
+
+        unit_add_to_gc_queue(u);
+}
+
+int unit_watch_pid(Unit *u, pid_t pid) {
+        int r;
+
+        assert(u);
+        assert(pid_is_valid(pid));
+
+        /* Watch a specific PID */
+
+        r = set_ensure_allocated(&u->pids, NULL);
+        if (r < 0)
+                return r;
+
+        r = hashmap_ensure_allocated(&u->manager->watch_pids, NULL);
+        if (r < 0)
+                return r;
+
+        /* First try, let's add the unit keyed by "pid". */
+        r = hashmap_put(u->manager->watch_pids, PID_TO_PTR(pid), u);
+        if (r == -EEXIST)  {
+                Unit **array;
+                bool found = false;
+                size_t n = 0;
+
+                /* OK, the "pid" key is already assigned to a different unit. Let's see if the "-pid" key (which points
+                 * to an array of Units rather than just a Unit), lists us already. */
+
+                array = hashmap_get(u->manager->watch_pids, PID_TO_PTR(-pid));
+                if (array)
+                        for (; array[n]; n++)
+                                if (array[n] == u)
+                                        found = true;
+
+                if (found) /* Found it already? if so, do nothing */
+                        r = 0;
+                else {
+                        Unit **new_array;
+
+                        /* Allocate a new array */
+                        new_array = new(Unit*, n + 2);
+                        if (!new_array)
+                                return -ENOMEM;
+
+                        memcpy_safe(new_array, array, sizeof(Unit*) * n);
+                        new_array[n] = u;
+                        new_array[n+1] = NULL;
+
+                        /* Add or replace the old array */
+                        r = hashmap_replace(u->manager->watch_pids, PID_TO_PTR(-pid), new_array);
+                        if (r < 0) {
+                                free(new_array);
+                                return r;
+                        }
+
+                        free(array);
+                }
+        } else if (r < 0)
+                return r;
+
+        r = set_put(u->pids, PID_TO_PTR(pid));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+void unit_unwatch_pid(Unit *u, pid_t pid) {
+        Unit **array;
+
+        assert(u);
+        assert(pid_is_valid(pid));
+
+        /* First let's drop the unit in case it's keyed as "pid". */
+        (void) hashmap_remove_value(u->manager->watch_pids, PID_TO_PTR(pid), u);
+
+        /* Then, let's also drop the unit, in case it's in the array keyed by -pid */
+        array = hashmap_get(u->manager->watch_pids, PID_TO_PTR(-pid));
+        if (array) {
+                size_t n, m = 0;
+
+                /* Let's iterate through the array, dropping our own entry */
+                for (n = 0; array[n]; n++)
+                        if (array[n] != u)
+                                array[m++] = array[n];
+                array[m] = NULL;
+
+                if (m == 0) {
+                        /* The array is now empty, remove the entire entry */
+                        assert(hashmap_remove(u->manager->watch_pids, PID_TO_PTR(-pid)) == array);
+                        free(array);
+                }
+        }
+
+        (void) set_remove(u->pids, PID_TO_PTR(pid));
+}
+
+void unit_unwatch_all_pids(Unit *u) {
+        assert(u);
+
+        while (!set_isempty(u->pids))
+                unit_unwatch_pid(u, PTR_TO_PID(set_first(u->pids)));
+
+        u->pids = set_free(u->pids);
+}
+
+static void unit_tidy_watch_pids(Unit *u) {
+        pid_t except1, except2;
+        Iterator i;
+        void *e;
+
+        assert(u);
+
+        /* Cleans dead PIDs from our list */
+
+        except1 = unit_main_pid(u);
+        except2 = unit_control_pid(u);
+
+        SET_FOREACH(e, u->pids, i) {
+                pid_t pid = PTR_TO_PID(e);
+
+                if (pid == except1 || pid == except2)
+                        continue;
+
+                if (!pid_is_unwaited(pid))
+                        unit_unwatch_pid(u, pid);
+        }
+}
+
+static int on_rewatch_pids_event(sd_event_source *s, void *userdata) {
+        Unit *u = userdata;
+
+        assert(s);
+        assert(u);
+
+        unit_tidy_watch_pids(u);
+        unit_watch_all_pids(u);
+
+        /* If the PID set is empty now, then let's finish this off. */
+        unit_synthesize_cgroup_empty_event(u);
+
+        return 0;
+}
+
+int unit_enqueue_rewatch_pids(Unit *u) {
+        int r;
+
+        assert(u);
+
+        if (!u->cgroup_path)
+                return -ENOENT;
+
+        r = cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER);
+        if (r < 0)
+                return r;
+        if (r > 0) /* On unified we can use proper notifications */
+                return 0;
+
+        /* Enqueues a low-priority job that will clean up dead PIDs from our list of PIDs to watch and subscribe to new
+         * PIDs that might have appeared. We do this in a delayed job because the work might be quite slow, as it
+         * involves issuing kill(pid, 0) on all processes we watch. */
+
+        if (!u->rewatch_pids_event_source) {
+                _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
+
+                r = sd_event_add_defer(u->manager->event, &s, on_rewatch_pids_event, u);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to allocate event source for tidying watched PIDs: %m");
+
+                r = sd_event_source_set_priority(s, SD_EVENT_PRIORITY_IDLE);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to adjust priority of event source for tidying watched PIDs: m");
+
+                (void) sd_event_source_set_description(s, "tidy-watch-pids");
+
+                u->rewatch_pids_event_source = TAKE_PTR(s);
+        }
+
+        r = sd_event_source_set_enabled(u->rewatch_pids_event_source, SD_EVENT_ONESHOT);
+        if (r < 0)
+                return log_error_errno(r, "Failed to enable event source for tidying watched PIDs: %m");
+
+        return 0;
+}
+
+void unit_dequeue_rewatch_pids(Unit *u) {
+        int r;
+        assert(u);
+
+        if (!u->rewatch_pids_event_source)
+                return;
+
+        r = sd_event_source_set_enabled(u->rewatch_pids_event_source, SD_EVENT_OFF);
+        if (r < 0)
+                log_warning_errno(r, "Failed to disable event source for tidying watched PIDs, ignoring: %m");
+
+        u->rewatch_pids_event_source = sd_event_source_unref(u->rewatch_pids_event_source);
+}
+
+bool unit_job_is_applicable(Unit *u, JobType j) {
+        assert(u);
+        assert(j >= 0 && j < _JOB_TYPE_MAX);
+
+        switch (j) {
+
+        case JOB_VERIFY_ACTIVE:
+        case JOB_START:
+        case JOB_NOP:
+                /* Note that we don't check unit_can_start() here. That's because .device units and suchlike are not
+                 * startable by us but may appear due to external events, and it thus makes sense to permit enqueing
+                 * jobs for it. */
+                return true;
+
+        case JOB_STOP:
+                /* Similar as above. However, perpetual units can never be stopped (neither explicitly nor due to
+                 * external events), hence it makes no sense to permit enqueing such a request either. */
+                return !u->perpetual;
+
+        case JOB_RESTART:
+        case JOB_TRY_RESTART:
+                return unit_can_stop(u) && unit_can_start(u);
+
+        case JOB_RELOAD:
+        case JOB_TRY_RELOAD:
+                return unit_can_reload(u);
+
+        case JOB_RELOAD_OR_START:
+                return unit_can_reload(u) && unit_can_start(u);
+
+        default:
+                assert_not_reached("Invalid job type");
+        }
+}
+
+static void maybe_warn_about_dependency(Unit *u, const char *other, UnitDependency dependency) {
+        assert(u);
+
+        /* Only warn about some unit types */
+        if (!IN_SET(dependency, UNIT_CONFLICTS, UNIT_CONFLICTED_BY, UNIT_BEFORE, UNIT_AFTER, UNIT_ON_FAILURE, UNIT_TRIGGERS, UNIT_TRIGGERED_BY))
+                return;
+
+        if (streq_ptr(u->id, other))
+                log_unit_warning(u, "Dependency %s=%s dropped", unit_dependency_to_string(dependency), u->id);
+        else
+                log_unit_warning(u, "Dependency %s=%s dropped, merged into %s", unit_dependency_to_string(dependency), strna(other), u->id);
+}
+
+static int unit_add_dependency_hashmap(
+                Hashmap **h,
+                Unit *other,
+                UnitDependencyMask origin_mask,
+                UnitDependencyMask destination_mask) {
+
+        UnitDependencyInfo info;
+        int r;
+
+        assert(h);
+        assert(other);
+        assert(origin_mask < _UNIT_DEPENDENCY_MASK_FULL);
+        assert(destination_mask < _UNIT_DEPENDENCY_MASK_FULL);
+        assert(origin_mask > 0 || destination_mask > 0);
+
+        r = hashmap_ensure_allocated(h, NULL);
+        if (r < 0)
+                return r;
+
+        assert_cc(sizeof(void*) == sizeof(info));
+
+        info.data = hashmap_get(*h, other);
+        if (info.data) {
+                /* Entry already exists. Add in our mask. */
+
+                if (FLAGS_SET(origin_mask, info.origin_mask) &&
+                    FLAGS_SET(destination_mask, info.destination_mask))
+                        return 0; /* NOP */
+
+                info.origin_mask |= origin_mask;
+                info.destination_mask |= destination_mask;
+
+                r = hashmap_update(*h, other, info.data);
+        } else {
+                info = (UnitDependencyInfo) {
+                        .origin_mask = origin_mask,
+                        .destination_mask = destination_mask,
+                };
+
+                r = hashmap_put(*h, other, info.data);
+        }
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int unit_add_dependency(
+                Unit *u,
+                UnitDependency d,
+                Unit *other,
+                bool add_reference,
+                UnitDependencyMask mask) {
+
+        static const UnitDependency inverse_table[_UNIT_DEPENDENCY_MAX] = {
+                [UNIT_REQUIRES] = UNIT_REQUIRED_BY,
+                [UNIT_WANTS] = UNIT_WANTED_BY,
+                [UNIT_REQUISITE] = UNIT_REQUISITE_OF,
+                [UNIT_BINDS_TO] = UNIT_BOUND_BY,
+                [UNIT_PART_OF] = UNIT_CONSISTS_OF,
+                [UNIT_REQUIRED_BY] = UNIT_REQUIRES,
+                [UNIT_REQUISITE_OF] = UNIT_REQUISITE,
+                [UNIT_WANTED_BY] = UNIT_WANTS,
+                [UNIT_BOUND_BY] = UNIT_BINDS_TO,
+                [UNIT_CONSISTS_OF] = UNIT_PART_OF,
+                [UNIT_CONFLICTS] = UNIT_CONFLICTED_BY,
+                [UNIT_CONFLICTED_BY] = UNIT_CONFLICTS,
+                [UNIT_BEFORE] = UNIT_AFTER,
+                [UNIT_AFTER] = UNIT_BEFORE,
+                [UNIT_ON_FAILURE] = _UNIT_DEPENDENCY_INVALID,
+                [UNIT_REFERENCES] = UNIT_REFERENCED_BY,
+                [UNIT_REFERENCED_BY] = UNIT_REFERENCES,
+                [UNIT_TRIGGERS] = UNIT_TRIGGERED_BY,
+                [UNIT_TRIGGERED_BY] = UNIT_TRIGGERS,
+                [UNIT_PROPAGATES_RELOAD_TO] = UNIT_RELOAD_PROPAGATED_FROM,
+                [UNIT_RELOAD_PROPAGATED_FROM] = UNIT_PROPAGATES_RELOAD_TO,
+                [UNIT_JOINS_NAMESPACE_OF] = UNIT_JOINS_NAMESPACE_OF,
+        };
+        Unit *original_u = u, *original_other = other;
+        int r;
+
+        assert(u);
+        assert(d >= 0 && d < _UNIT_DEPENDENCY_MAX);
+        assert(other);
+
+        u = unit_follow_merge(u);
+        other = unit_follow_merge(other);
+
+        /* We won't allow dependencies on ourselves. We will not
+         * consider them an error however. */
+        if (u == other) {
+                maybe_warn_about_dependency(original_u, original_other->id, d);
+                return 0;
+        }
+
+        if ((d == UNIT_BEFORE && other->type == UNIT_DEVICE) ||
+            (d == UNIT_AFTER && u->type == UNIT_DEVICE)) {
+                log_unit_warning(u, "Dependency Before=%s ignored (.device units cannot be delayed)", other->id);
+                return 0;
+        }
+
+        r = unit_add_dependency_hashmap(u->dependencies + d, other, mask, 0);
+        if (r < 0)
+                return r;
+
+        if (inverse_table[d] != _UNIT_DEPENDENCY_INVALID && inverse_table[d] != d) {
+                r = unit_add_dependency_hashmap(other->dependencies + inverse_table[d], u, 0, mask);
+                if (r < 0)
+                        return r;
+        }
+
+        if (add_reference) {
+                r = unit_add_dependency_hashmap(u->dependencies + UNIT_REFERENCES, other, mask, 0);
+                if (r < 0)
+                        return r;
+
+                r = unit_add_dependency_hashmap(other->dependencies + UNIT_REFERENCED_BY, u, 0, mask);
+                if (r < 0)
+                        return r;
+        }
+
+        unit_add_to_dbus_queue(u);
+        return 0;
+}
+
+int unit_add_two_dependencies(Unit *u, UnitDependency d, UnitDependency e, Unit *other, bool add_reference, UnitDependencyMask mask) {
+        int r;
+
+        assert(u);
+
+        r = unit_add_dependency(u, d, other, add_reference, mask);
+        if (r < 0)
+                return r;
+
+        return unit_add_dependency(u, e, other, add_reference, mask);
+}
+
+static int resolve_template(Unit *u, const char *name, char **buf, const char **ret) {
+        int r;
+
+        assert(u);
+        assert(name);
+        assert(buf);
+        assert(ret);
+
+        if (!unit_name_is_valid(name, UNIT_NAME_TEMPLATE)) {
+                *buf = NULL;
+                *ret = name;
+                return 0;
+        }
+
+        if (u->instance)
+                r = unit_name_replace_instance(name, u->instance, buf);
+        else {
+                _cleanup_free_ char *i = NULL;
+
+                r = unit_name_to_prefix(u->id, &i);
+                if (r < 0)
+                        return r;
+
+                r = unit_name_replace_instance(name, i, buf);
+        }
+        if (r < 0)
+                return r;
+
+        *ret = *buf;
+        return 0;
+}
+
+int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, bool add_reference, UnitDependencyMask mask) {
+        _cleanup_free_ char *buf = NULL;
+        Unit *other;
+        int r;
+
+        assert(u);
+        assert(name);
+
+        r = resolve_template(u, name, &buf, &name);
+        if (r < 0)
+                return r;
+
+        r = manager_load_unit(u->manager, name, NULL, NULL, &other);
+        if (r < 0)
+                return r;
+
+        return unit_add_dependency(u, d, other, add_reference, mask);
+}
+
+int unit_add_two_dependencies_by_name(Unit *u, UnitDependency d, UnitDependency e, const char *name, bool add_reference, UnitDependencyMask mask) {
+        _cleanup_free_ char *buf = NULL;
+        Unit *other;
+        int r;
+
+        assert(u);
+        assert(name);
+
+        r = resolve_template(u, name, &buf, &name);
+        if (r < 0)
+                return r;
+
+        r = manager_load_unit(u->manager, name, NULL, NULL, &other);
+        if (r < 0)
+                return r;
+
+        return unit_add_two_dependencies(u, d, e, other, add_reference, mask);
+}
+
+int set_unit_path(const char *p) {
+        /* This is mostly for debug purposes */
+        if (setenv("SYSTEMD_UNIT_PATH", p, 1) < 0)
+                return -errno;
+
+        return 0;
+}
+
+char *unit_dbus_path(Unit *u) {
+        assert(u);
+
+        if (!u->id)
+                return NULL;
+
+        return unit_dbus_path_from_name(u->id);
+}
+
+char *unit_dbus_path_invocation_id(Unit *u) {
+        assert(u);
+
+        if (sd_id128_is_null(u->invocation_id))
+                return NULL;
+
+        return unit_dbus_path_from_name(u->invocation_id_string);
+}
+
+int unit_set_slice(Unit *u, Unit *slice) {
+        assert(u);
+        assert(slice);
+
+        /* Sets the unit slice if it has not been set before. Is extra
+         * careful, to only allow this for units that actually have a
+         * cgroup context. Also, we don't allow to set this for slices
+         * (since the parent slice is derived from the name). Make
+         * sure the unit we set is actually a slice. */
+
+        if (!UNIT_HAS_CGROUP_CONTEXT(u))
+                return -EOPNOTSUPP;
+
+        if (u->type == UNIT_SLICE)
+                return -EINVAL;
+
+        if (unit_active_state(u) != UNIT_INACTIVE)
+                return -EBUSY;
+
+        if (slice->type != UNIT_SLICE)
+                return -EINVAL;
+
+        if (unit_has_name(u, SPECIAL_INIT_SCOPE) &&
+            !unit_has_name(slice, SPECIAL_ROOT_SLICE))
+                return -EPERM;
+
+        if (UNIT_DEREF(u->slice) == slice)
+                return 0;
+
+        /* Disallow slice changes if @u is already bound to cgroups */
+        if (UNIT_ISSET(u->slice) && u->cgroup_realized)
+                return -EBUSY;
+
+        unit_ref_set(&u->slice, u, slice);
+        return 1;
+}
+
+int unit_set_default_slice(Unit *u) {
+        const char *slice_name;
+        Unit *slice;
+        int r;
+
+        assert(u);
+
+        if (UNIT_ISSET(u->slice))
+                return 0;
+
+        if (u->instance) {
+                _cleanup_free_ char *prefix = NULL, *escaped = NULL;
+
+                /* Implicitly place all instantiated units in their
+                 * own per-template slice */
+
+                r = unit_name_to_prefix(u->id, &prefix);
+                if (r < 0)
+                        return r;
+
+                /* The prefix is already escaped, but it might include
+                 * "-" which has a special meaning for slice units,
+                 * hence escape it here extra. */
+                escaped = unit_name_escape(prefix);
+                if (!escaped)
+                        return -ENOMEM;
+
+                if (MANAGER_IS_SYSTEM(u->manager))
+                        slice_name = strjoina("system-", escaped, ".slice");
+                else
+                        slice_name = strjoina(escaped, ".slice");
+        } else
+                slice_name =
+                        MANAGER_IS_SYSTEM(u->manager) && !unit_has_name(u, SPECIAL_INIT_SCOPE)
+                        ? SPECIAL_SYSTEM_SLICE
+                        : SPECIAL_ROOT_SLICE;
+
+        r = manager_load_unit(u->manager, slice_name, NULL, NULL, &slice);
+        if (r < 0)
+                return r;
+
+        return unit_set_slice(u, slice);
+}
+
+const char *unit_slice_name(Unit *u) {
+        assert(u);
+
+        if (!UNIT_ISSET(u->slice))
+                return NULL;
+
+        return UNIT_DEREF(u->slice)->id;
+}
+
+int unit_load_related_unit(Unit *u, const char *type, Unit **_found) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        assert(u);
+        assert(type);
+        assert(_found);
+
+        r = unit_name_change_suffix(u->id, type, &t);
+        if (r < 0)
+                return r;
+        if (unit_has_name(u, t))
+                return -EINVAL;
+
+        r = manager_load_unit(u->manager, t, NULL, NULL, _found);
+        assert(r < 0 || *_found != u);
+        return r;
+}
+
+static int signal_name_owner_changed(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        const char *name, *old_owner, *new_owner;
+        Unit *u = userdata;
+        int r;
+
+        assert(message);
+        assert(u);
+
+        r = sd_bus_message_read(message, "sss", &name, &old_owner, &new_owner);
+        if (r < 0) {
+                bus_log_parse_error(r);
+                return 0;
+        }
+
+        old_owner = empty_to_null(old_owner);
+        new_owner = empty_to_null(new_owner);
+
+        if (UNIT_VTABLE(u)->bus_name_owner_change)
+                UNIT_VTABLE(u)->bus_name_owner_change(u, name, old_owner, new_owner);
+
+        return 0;
+}
+
+int unit_install_bus_match(Unit *u, sd_bus *bus, const char *name) {
+        const char *match;
+
+        assert(u);
+        assert(bus);
+        assert(name);
+
+        if (u->match_bus_slot)
+                return -EBUSY;
+
+        match = strjoina("type='signal',"
+                         "sender='org.freedesktop.DBus',"
+                         "path='/org/freedesktop/DBus',"
+                         "interface='org.freedesktop.DBus',"
+                         "member='NameOwnerChanged',"
+                         "arg0='", name, "'");
+
+        return sd_bus_add_match_async(bus, &u->match_bus_slot, match, signal_name_owner_changed, NULL, u);
+}
+
+int unit_watch_bus_name(Unit *u, const char *name) {
+        int r;
+
+        assert(u);
+        assert(name);
+
+        /* Watch a specific name on the bus. We only support one unit
+         * watching each name for now. */
+
+        if (u->manager->api_bus) {
+                /* If the bus is already available, install the match directly.
+                 * Otherwise, just put the name in the list. bus_setup_api() will take care later. */
+                r = unit_install_bus_match(u, u->manager->api_bus, name);
+                if (r < 0)
+                        return log_warning_errno(r, "Failed to subscribe to NameOwnerChanged signal for '%s': %m", name);
+        }
+
+        r = hashmap_put(u->manager->watch_bus, name, u);
+        if (r < 0) {
+                u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+                return log_warning_errno(r, "Failed to put bus name to hashmap: %m");
+        }
+
+        return 0;
+}
+
+void unit_unwatch_bus_name(Unit *u, const char *name) {
+        assert(u);
+        assert(name);
+
+        (void) hashmap_remove_value(u->manager->watch_bus, name, u);
+        u->match_bus_slot = sd_bus_slot_unref(u->match_bus_slot);
+}
+
+bool unit_can_serialize(Unit *u) {
+        assert(u);
+
+        return UNIT_VTABLE(u)->serialize && UNIT_VTABLE(u)->deserialize_item;
+}
+
+static int serialize_cgroup_mask(FILE *f, const char *key, CGroupMask mask) {
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert(f);
+        assert(key);
+
+        if (mask == 0)
+                return 0;
+
+        r = cg_mask_to_string(mask, &s);
+        if (r < 0)
+                return log_error_errno(r, "Failed to format cgroup mask: %m");
+
+        return serialize_item(f, key, s);
+}
+
+static const char *ip_accounting_metric_field[_CGROUP_IP_ACCOUNTING_METRIC_MAX] = {
+        [CGROUP_IP_INGRESS_BYTES] = "ip-accounting-ingress-bytes",
+        [CGROUP_IP_INGRESS_PACKETS] = "ip-accounting-ingress-packets",
+        [CGROUP_IP_EGRESS_BYTES] = "ip-accounting-egress-bytes",
+        [CGROUP_IP_EGRESS_PACKETS] = "ip-accounting-egress-packets",
+};
+
+int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
+        CGroupIPAccountingMetric m;
+        int r;
+
+        assert(u);
+        assert(f);
+        assert(fds);
+
+        if (unit_can_serialize(u)) {
+                r = UNIT_VTABLE(u)->serialize(u, f, fds);
+                if (r < 0)
+                        return r;
+        }
+
+        (void) serialize_dual_timestamp(f, "state-change-timestamp", &u->state_change_timestamp);
+
+        (void) serialize_dual_timestamp(f, "inactive-exit-timestamp", &u->inactive_exit_timestamp);
+        (void) serialize_dual_timestamp(f, "active-enter-timestamp", &u->active_enter_timestamp);
+        (void) serialize_dual_timestamp(f, "active-exit-timestamp", &u->active_exit_timestamp);
+        (void) serialize_dual_timestamp(f, "inactive-enter-timestamp", &u->inactive_enter_timestamp);
+
+        (void) serialize_dual_timestamp(f, "condition-timestamp", &u->condition_timestamp);
+        (void) serialize_dual_timestamp(f, "assert-timestamp", &u->assert_timestamp);
+
+        if (dual_timestamp_is_set(&u->condition_timestamp))
+                (void) serialize_bool(f, "condition-result", u->condition_result);
+
+        if (dual_timestamp_is_set(&u->assert_timestamp))
+                (void) serialize_bool(f, "assert-result", u->assert_result);
+
+        (void) serialize_bool(f, "transient", u->transient);
+        (void) serialize_bool(f, "in-audit", u->in_audit);
+
+        (void) serialize_bool(f, "exported-invocation-id", u->exported_invocation_id);
+        (void) serialize_bool(f, "exported-log-level-max", u->exported_log_level_max);
+        (void) serialize_bool(f, "exported-log-extra-fields", u->exported_log_extra_fields);
+        (void) serialize_bool(f, "exported-log-rate-limit-interval", u->exported_log_rate_limit_interval);
+        (void) serialize_bool(f, "exported-log-rate-limit-burst", u->exported_log_rate_limit_burst);
+
+        (void) serialize_item_format(f, "cpu-usage-base", "%" PRIu64, u->cpu_usage_base);
+        if (u->cpu_usage_last != NSEC_INFINITY)
+                (void) serialize_item_format(f, "cpu-usage-last", "%" PRIu64, u->cpu_usage_last);
+
+        if (u->cgroup_path)
+                (void) serialize_item(f, "cgroup", u->cgroup_path);
+
+        (void) serialize_bool(f, "cgroup-realized", u->cgroup_realized);
+        (void) serialize_cgroup_mask(f, "cgroup-realized-mask", u->cgroup_realized_mask);
+        (void) serialize_cgroup_mask(f, "cgroup-enabled-mask", u->cgroup_enabled_mask);
+        (void) serialize_cgroup_mask(f, "cgroup-invalidated-mask", u->cgroup_invalidated_mask);
+
+        if (uid_is_valid(u->ref_uid))
+                (void) serialize_item_format(f, "ref-uid", UID_FMT, u->ref_uid);
+        if (gid_is_valid(u->ref_gid))
+                (void) serialize_item_format(f, "ref-gid", GID_FMT, u->ref_gid);
+
+        if (!sd_id128_is_null(u->invocation_id))
+                (void) serialize_item_format(f, "invocation-id", SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(u->invocation_id));
+
+        bus_track_serialize(u->bus_track, f, "ref");
+
+        for (m = 0; m < _CGROUP_IP_ACCOUNTING_METRIC_MAX; m++) {
+                uint64_t v;
+
+                r = unit_get_ip_accounting(u, m, &v);
+                if (r >= 0)
+                        (void) serialize_item_format(f, ip_accounting_metric_field[m], "%" PRIu64, v);
+        }
+
+        if (serialize_jobs) {
+                if (u->job) {
+                        fputs("job\n", f);
+                        job_serialize(u->job, f);
+                }
+
+                if (u->nop_job) {
+                        fputs("job\n", f);
+                        job_serialize(u->nop_job, f);
+                }
+        }
+
+        /* End marker */
+        fputc('\n', f);
+        return 0;
+}
+
+static int unit_deserialize_job(Unit *u, FILE *f) {
+        _cleanup_(job_freep) Job *j = NULL;
+        int r;
+
+        assert(u);
+        assert(f);
+
+        j = job_new_raw(u);
+        if (!j)
+                return log_oom();
+
+        r = job_deserialize(j, f);
+        if (r < 0)
+                return r;
+
+        r = job_install_deserialized(j);
+        if (r < 0)
+                return r;
+
+        TAKE_PTR(j);
+        return 0;
+}
+
+int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
+        int r;
+
+        assert(u);
+        assert(f);
+        assert(fds);
+
+        for (;;) {
+                _cleanup_free_ char *line = NULL;
+                CGroupIPAccountingMetric m;
+                char *l, *v;
+                size_t k;
+
+                r = read_line(f, LONG_LINE_MAX, &line);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to read serialization line: %m");
+                if (r == 0) /* eof */
+                        break;
+
+                l = strstrip(line);
+                if (isempty(l)) /* End marker */
+                        break;
+
+                k = strcspn(l, "=");
+
+                if (l[k] == '=') {
+                        l[k] = 0;
+                        v = l+k+1;
+                } else
+                        v = l+k;
+
+                if (streq(l, "job")) {
+                        if (v[0] == '\0') {
+                                /* New-style serialized job */
+                                r = unit_deserialize_job(u, f);
+                                if (r < 0)
+                                        return r;
+                        } else  /* Legacy for pre-44 */
+                                log_unit_warning(u, "Update from too old systemd versions are unsupported, cannot deserialize job: %s", v);
+                        continue;
+                } else if (streq(l, "state-change-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->state_change_timestamp);
+                        continue;
+                } else if (streq(l, "inactive-exit-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->inactive_exit_timestamp);
+                        continue;
+                } else if (streq(l, "active-enter-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->active_enter_timestamp);
+                        continue;
+                } else if (streq(l, "active-exit-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->active_exit_timestamp);
+                        continue;
+                } else if (streq(l, "inactive-enter-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->inactive_enter_timestamp);
+                        continue;
+                } else if (streq(l, "condition-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->condition_timestamp);
+                        continue;
+                } else if (streq(l, "assert-timestamp")) {
+                        (void) deserialize_dual_timestamp(v, &u->assert_timestamp);
+                        continue;
+                } else if (streq(l, "condition-result")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse condition result value %s, ignoring.", v);
+                        else
+                                u->condition_result = r;
+
+                        continue;
+
+                } else if (streq(l, "assert-result")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse assert result value %s, ignoring.", v);
+                        else
+                                u->assert_result = r;
+
+                        continue;
+
+                } else if (streq(l, "transient")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse transient bool %s, ignoring.", v);
+                        else
+                                u->transient = r;
+
+                        continue;
+
+                } else if (streq(l, "in-audit")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse in-audit bool %s, ignoring.", v);
+                        else
+                                u->in_audit = r;
+
+                        continue;
+
+                } else if (streq(l, "exported-invocation-id")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse exported invocation ID bool %s, ignoring.", v);
+                        else
+                                u->exported_invocation_id = r;
+
+                        continue;
+
+                } else if (streq(l, "exported-log-level-max")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse exported log level max bool %s, ignoring.", v);
+                        else
+                                u->exported_log_level_max = r;
+
+                        continue;
+
+                } else if (streq(l, "exported-log-extra-fields")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse exported log extra fields bool %s, ignoring.", v);
+                        else
+                                u->exported_log_extra_fields = r;
+
+                        continue;
+
+                } else if (streq(l, "exported-log-rate-limit-interval")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse exported log rate limit interval %s, ignoring.", v);
+                        else
+                                u->exported_log_rate_limit_interval = r;
+
+                        continue;
+
+                } else if (streq(l, "exported-log-rate-limit-burst")) {
+
+                        r = parse_boolean(v);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse exported log rate limit burst %s, ignoring.", v);
+                        else
+                                u->exported_log_rate_limit_burst = r;
+
+                        continue;
+
+                } else if (STR_IN_SET(l, "cpu-usage-base", "cpuacct-usage-base")) {
+
+                        r = safe_atou64(v, &u->cpu_usage_base);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse CPU usage base %s, ignoring.", v);
+
+                        continue;
+
+                } else if (streq(l, "cpu-usage-last")) {
+
+                        r = safe_atou64(v, &u->cpu_usage_last);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to read CPU usage last %s, ignoring.", v);
+
+                        continue;
+
+                } else if (streq(l, "cgroup")) {
+
+                        r = unit_set_cgroup_path(u, v);
+                        if (r < 0)
+                                log_unit_debug_errno(u, r, "Failed to set cgroup path %s, ignoring: %m", v);
+
+                        (void) unit_watch_cgroup(u);
+
+                        continue;
+                } else if (streq(l, "cgroup-realized")) {
+                        int b;
+
+                        b = parse_boolean(v);
+                        if (b < 0)
+                                log_unit_debug(u, "Failed to parse cgroup-realized bool %s, ignoring.", v);
+                        else
+                                u->cgroup_realized = b;
+
+                        continue;
+
+                } else if (streq(l, "cgroup-realized-mask")) {
+
+                        r = cg_mask_from_string(v, &u->cgroup_realized_mask);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse cgroup-realized-mask %s, ignoring.", v);
+                        continue;
+
+                } else if (streq(l, "cgroup-enabled-mask")) {
+
+                        r = cg_mask_from_string(v, &u->cgroup_enabled_mask);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse cgroup-enabled-mask %s, ignoring.", v);
+                        continue;
+
+                } else if (streq(l, "cgroup-invalidated-mask")) {
+
+                        r = cg_mask_from_string(v, &u->cgroup_invalidated_mask);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse cgroup-invalidated-mask %s, ignoring.", v);
+                        continue;
+
+                } else if (streq(l, "ref-uid")) {
+                        uid_t uid;
+
+                        r = parse_uid(v, &uid);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse referenced UID %s, ignoring.", v);
+                        else
+                                unit_ref_uid_gid(u, uid, GID_INVALID);
+
+                        continue;
+
+                } else if (streq(l, "ref-gid")) {
+                        gid_t gid;
+
+                        r = parse_gid(v, &gid);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse referenced GID %s, ignoring.", v);
+                        else
+                                unit_ref_uid_gid(u, UID_INVALID, gid);
+
+                        continue;
+
+                } else if (streq(l, "ref")) {
+
+                        r = strv_extend(&u->deserialized_refs, v);
+                        if (r < 0)
+                                return log_oom();
+
+                        continue;
+                } else if (streq(l, "invocation-id")) {
+                        sd_id128_t id;
+
+                        r = sd_id128_from_string(v, &id);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse invocation id %s, ignoring.", v);
+                        else {
+                                r = unit_set_invocation_id(u, id);
+                                if (r < 0)
+                                        log_unit_warning_errno(u, r, "Failed to set invocation ID for unit: %m");
+                        }
+
+                        continue;
+                }
+
+                /* Check if this is an IP accounting metric serialization field */
+                for (m = 0; m < _CGROUP_IP_ACCOUNTING_METRIC_MAX; m++)
+                        if (streq(l, ip_accounting_metric_field[m]))
+                                break;
+                if (m < _CGROUP_IP_ACCOUNTING_METRIC_MAX) {
+                        uint64_t c;
+
+                        r = safe_atou64(v, &c);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse IP accounting value %s, ignoring.", v);
+                        else
+                                u->ip_accounting_extra[m] = c;
+                        continue;
+                }
+
+                if (unit_can_serialize(u)) {
+                        r = exec_runtime_deserialize_compat(u, l, v, fds);
+                        if (r < 0) {
+                                log_unit_warning(u, "Failed to deserialize runtime parameter '%s', ignoring.", l);
+                                continue;
+                        }
+
+                        /* Returns positive if key was handled by the call */
+                        if (r > 0)
+                                continue;
+
+                        r = UNIT_VTABLE(u)->deserialize_item(u, l, v, fds);
+                        if (r < 0)
+                                log_unit_warning(u, "Failed to deserialize unit parameter '%s', ignoring.", l);
+                }
+        }
+
+        /* Versions before 228 did not carry a state change timestamp. In this case, take the current time. This is
+         * useful, so that timeouts based on this timestamp don't trigger too early, and is in-line with the logic from
+         * before 228 where the base for timeouts was not persistent across reboots. */
+
+        if (!dual_timestamp_is_set(&u->state_change_timestamp))
+                dual_timestamp_get(&u->state_change_timestamp);
+
+        /* Let's make sure that everything that is deserialized also gets any potential new cgroup settings applied
+         * after we are done. For that we invalidate anything already realized, so that we can realize it again. */
+        unit_invalidate_cgroup(u, _CGROUP_MASK_ALL);
+        unit_invalidate_cgroup_bpf(u);
+
+        return 0;
+}
+
+int unit_deserialize_skip(FILE *f) {
+        int r;
+        assert(f);
+
+        /* Skip serialized data for this unit. We don't know what it is. */
+
+        for (;;) {
+                _cleanup_free_ char *line = NULL;
+                char *l;
+
+                r = read_line(f, LONG_LINE_MAX, &line);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to read serialization line: %m");
+                if (r == 0)
+                        return 0;
+
+                l = strstrip(line);
+
+                /* End marker */
+                if (isempty(l))
+                        return 1;
+        }
+}
+
+int unit_add_node_dependency(Unit *u, const char *what, bool wants, UnitDependency dep, UnitDependencyMask mask) {
+        Unit *device;
+        _cleanup_free_ char *e = NULL;
+        int r;
+
+        assert(u);
+
+        /* Adds in links to the device node that this unit is based on */
+        if (isempty(what))
+                return 0;
+
+        if (!is_device_path(what))
+                return 0;
+
+        /* When device units aren't supported (such as in a
+         * container), don't create dependencies on them. */
+        if (!unit_type_supported(UNIT_DEVICE))
+                return 0;
+
+        r = unit_name_from_path(what, ".device", &e);
+        if (r < 0)
+                return r;
+
+        r = manager_load_unit(u->manager, e, NULL, NULL, &device);
+        if (r < 0)
+                return r;
+
+        if (dep == UNIT_REQUIRES && device_shall_be_bound_by(device, u))
+                dep = UNIT_BINDS_TO;
+
+        r = unit_add_two_dependencies(u, UNIT_AFTER,
+                                      MANAGER_IS_SYSTEM(u->manager) ? dep : UNIT_WANTS,
+                                      device, true, mask);
+        if (r < 0)
+                return r;
+
+        if (wants) {
+                r = unit_add_dependency(device, UNIT_WANTS, u, false, mask);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int unit_coldplug(Unit *u) {
+        int r = 0, q;
+        char **i;
+
+        assert(u);
+
+        /* Make sure we don't enter a loop, when coldplugging recursively. */
+        if (u->coldplugged)
+                return 0;
+
+        u->coldplugged = true;
+
+        STRV_FOREACH(i, u->deserialized_refs) {
+                q = bus_unit_track_add_name(u, *i);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
+        u->deserialized_refs = strv_free(u->deserialized_refs);
+
+        if (UNIT_VTABLE(u)->coldplug) {
+                q = UNIT_VTABLE(u)->coldplug(u);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
+
+        if (u->job) {
+                q = job_coldplug(u->job);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+void unit_catchup(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->catchup)
+                UNIT_VTABLE(u)->catchup(u);
+}
+
+static bool fragment_mtime_newer(const char *path, usec_t mtime, bool path_masked) {
+        struct stat st;
+
+        if (!path)
+                return false;
+
+        /* If the source is some virtual kernel file system, then we assume we watch it anyway, and hence pretend we
+         * are never out-of-date. */
+        if (PATH_STARTSWITH_SET(path, "/proc", "/sys"))
+                return false;
+
+        if (stat(path, &st) < 0)
+                /* What, cannot access this anymore? */
+                return true;
+
+        if (path_masked)
+                /* For masked files check if they are still so */
+                return !null_or_empty(&st);
+        else
+                /* For non-empty files check the mtime */
+                return timespec_load(&st.st_mtim) > mtime;
+
+        return false;
+}
+
+bool unit_need_daemon_reload(Unit *u) {
+        _cleanup_strv_free_ char **t = NULL;
+        char **path;
+
+        assert(u);
+
+        /* For unit files, we allow masking… */
+        if (fragment_mtime_newer(u->fragment_path, u->fragment_mtime,
+                                 u->load_state == UNIT_MASKED))
+                return true;
+
+        /* Source paths should not be masked… */
+        if (fragment_mtime_newer(u->source_path, u->source_mtime, false))
+                return true;
+
+        if (u->load_state == UNIT_LOADED)
+                (void) unit_find_dropin_paths(u, &t);
+        if (!strv_equal(u->dropin_paths, t))
+                return true;
+
+        /* … any drop-ins that are masked are simply omitted from the list. */
+        STRV_FOREACH(path, u->dropin_paths)
+                if (fragment_mtime_newer(*path, u->dropin_mtime, false))
+                        return true;
+
+        return false;
+}
+
+void unit_reset_failed(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->reset_failed)
+                UNIT_VTABLE(u)->reset_failed(u);
+
+        RATELIMIT_RESET(u->start_limit);
+        u->start_limit_hit = false;
+}
+
+Unit *unit_following(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->following)
+                return UNIT_VTABLE(u)->following(u);
+
+        return NULL;
+}
+
+bool unit_stop_pending(Unit *u) {
+        assert(u);
+
+        /* This call does check the current state of the unit. It's
+         * hence useful to be called from state change calls of the
+         * unit itself, where the state isn't updated yet. This is
+         * different from unit_inactive_or_pending() which checks both
+         * the current state and for a queued job. */
+
+        return u->job && u->job->type == JOB_STOP;
+}
+
+bool unit_inactive_or_pending(Unit *u) {
+        assert(u);
+
+        /* Returns true if the unit is inactive or going down */
+
+        if (UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(u)))
+                return true;
+
+        if (unit_stop_pending(u))
+                return true;
+
+        return false;
+}
+
+bool unit_active_or_pending(Unit *u) {
+        assert(u);
+
+        /* Returns true if the unit is active or going up */
+
+        if (UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u)))
+                return true;
+
+        if (u->job &&
+            IN_SET(u->job->type, JOB_START, JOB_RELOAD_OR_START, JOB_RESTART))
+                return true;
+
+        return false;
+}
+
+bool unit_will_restart(Unit *u) {
+        assert(u);
+
+        if (!UNIT_VTABLE(u)->will_restart)
+                return false;
+
+        return UNIT_VTABLE(u)->will_restart(u);
+}
+
+int unit_kill(Unit *u, KillWho w, int signo, sd_bus_error *error) {
+        assert(u);
+        assert(w >= 0 && w < _KILL_WHO_MAX);
+        assert(SIGNAL_VALID(signo));
+
+        if (!UNIT_VTABLE(u)->kill)
+                return -EOPNOTSUPP;
+
+        return UNIT_VTABLE(u)->kill(u, w, signo, error);
+}
+
+static Set *unit_pid_set(pid_t main_pid, pid_t control_pid) {
+        _cleanup_set_free_ Set *pid_set = NULL;
+        int r;
+
+        pid_set = set_new(NULL);
+        if (!pid_set)
+                return NULL;
+
+        /* Exclude the main/control pids from being killed via the cgroup */
+        if (main_pid > 0) {
+                r = set_put(pid_set, PID_TO_PTR(main_pid));
+                if (r < 0)
+                        return NULL;
+        }
+
+        if (control_pid > 0) {
+                r = set_put(pid_set, PID_TO_PTR(control_pid));
+                if (r < 0)
+                        return NULL;
+        }
+
+        return TAKE_PTR(pid_set);
+}
+
+int unit_kill_common(
+                Unit *u,
+                KillWho who,
+                int signo,
+                pid_t main_pid,
+                pid_t control_pid,
+                sd_bus_error *error) {
+
+        int r = 0;
+        bool killed = false;
+
+        if (IN_SET(who, KILL_MAIN, KILL_MAIN_FAIL)) {
+                if (main_pid < 0)
+                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_PROCESS, "%s units have no main processes", unit_type_to_string(u->type));
+                else if (main_pid == 0)
+                        return sd_bus_error_set_const(error, BUS_ERROR_NO_SUCH_PROCESS, "No main process to kill");
+        }
+
+        if (IN_SET(who, KILL_CONTROL, KILL_CONTROL_FAIL)) {
+                if (control_pid < 0)
+                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_PROCESS, "%s units have no control processes", unit_type_to_string(u->type));
+                else if (control_pid == 0)
+                        return sd_bus_error_set_const(error, BUS_ERROR_NO_SUCH_PROCESS, "No control process to kill");
+        }
+
+        if (IN_SET(who, KILL_CONTROL, KILL_CONTROL_FAIL, KILL_ALL, KILL_ALL_FAIL))
+                if (control_pid > 0) {
+                        if (kill(control_pid, signo) < 0)
+                                r = -errno;
+                        else
+                                killed = true;
+                }
+
+        if (IN_SET(who, KILL_MAIN, KILL_MAIN_FAIL, KILL_ALL, KILL_ALL_FAIL))
+                if (main_pid > 0) {
+                        if (kill(main_pid, signo) < 0)
+                                r = -errno;
+                        else
+                                killed = true;
+                }
+
+        if (IN_SET(who, KILL_ALL, KILL_ALL_FAIL) && u->cgroup_path) {
+                _cleanup_set_free_ Set *pid_set = NULL;
+                int q;
+
+                /* Exclude the main/control pids from being killed via the cgroup */
+                pid_set = unit_pid_set(main_pid, control_pid);
+                if (!pid_set)
+                        return -ENOMEM;
+
+                q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, signo, 0, pid_set, NULL, NULL);
+                if (q < 0 && !IN_SET(q, -EAGAIN, -ESRCH, -ENOENT))
+                        r = q;
+                else
+                        killed = true;
+        }
+
+        if (r == 0 && !killed && IN_SET(who, KILL_ALL_FAIL, KILL_CONTROL_FAIL))
+                return -ESRCH;
+
+        return r;
+}
+
+int unit_following_set(Unit *u, Set **s) {
+        assert(u);
+        assert(s);
+
+        if (UNIT_VTABLE(u)->following_set)
+                return UNIT_VTABLE(u)->following_set(u, s);
+
+        *s = NULL;
+        return 0;
+}
+
+UnitFileState unit_get_unit_file_state(Unit *u) {
+        int r;
+
+        assert(u);
+
+        if (u->unit_file_state < 0 && u->fragment_path) {
+                r = unit_file_get_state(
+                                u->manager->unit_file_scope,
+                                NULL,
+                                u->id,
+                                &u->unit_file_state);
+                if (r < 0)
+                        u->unit_file_state = UNIT_FILE_BAD;
+        }
+
+        return u->unit_file_state;
+}
+
+int unit_get_unit_file_preset(Unit *u) {
+        assert(u);
+
+        if (u->unit_file_preset < 0 && u->fragment_path)
+                u->unit_file_preset = unit_file_query_preset(
+                                u->manager->unit_file_scope,
+                                NULL,
+                                basename(u->fragment_path));
+
+        return u->unit_file_preset;
+}
+
+Unit* unit_ref_set(UnitRef *ref, Unit *source, Unit *target) {
+        assert(ref);
+        assert(source);
+        assert(target);
+
+        if (ref->target)
+                unit_ref_unset(ref);
+
+        ref->source = source;
+        ref->target = target;
+        LIST_PREPEND(refs_by_target, target->refs_by_target, ref);
+        return target;
+}
+
+void unit_ref_unset(UnitRef *ref) {
+        assert(ref);
+
+        if (!ref->target)
+                return;
+
+        /* We are about to drop a reference to the unit, make sure the garbage collection has a look at it as it might
+         * be unreferenced now. */
+        unit_add_to_gc_queue(ref->target);
+
+        LIST_REMOVE(refs_by_target, ref->target->refs_by_target, ref);
+        ref->source = ref->target = NULL;
+}
+
+static int user_from_unit_name(Unit *u, char **ret) {
+
+        static const uint8_t hash_key[] = {
+                0x58, 0x1a, 0xaf, 0xe6, 0x28, 0x58, 0x4e, 0x96,
+                0xb4, 0x4e, 0xf5, 0x3b, 0x8c, 0x92, 0x07, 0xec
+        };
+
+        _cleanup_free_ char *n = NULL;
+        int r;
+
+        r = unit_name_to_prefix(u->id, &n);
+        if (r < 0)
+                return r;
+
+        if (valid_user_group_name(n)) {
+                *ret = TAKE_PTR(n);
+                return 0;
+        }
+
+        /* If we can't use the unit name as a user name, then let's hash it and use that */
+        if (asprintf(ret, "_du%016" PRIx64, siphash24(n, strlen(n), hash_key)) < 0)
+                return -ENOMEM;
+
+        return 0;
+}
+
+int unit_patch_contexts(Unit *u) {
+        CGroupContext *cc;
+        ExecContext *ec;
+        unsigned i;
+        int r;
+
+        assert(u);
+
+        /* Patch in the manager defaults into the exec and cgroup
+         * contexts, _after_ the rest of the settings have been
+         * initialized */
+
+        ec = unit_get_exec_context(u);
+        if (ec) {
+                /* This only copies in the ones that need memory */
+                for (i = 0; i < _RLIMIT_MAX; i++)
+                        if (u->manager->rlimit[i] && !ec->rlimit[i]) {
+                                ec->rlimit[i] = newdup(struct rlimit, u->manager->rlimit[i], 1);
+                                if (!ec->rlimit[i])
+                                        return -ENOMEM;
+                        }
+
+                if (MANAGER_IS_USER(u->manager) &&
+                    !ec->working_directory) {
+
+                        r = get_home_dir(&ec->working_directory);
+                        if (r < 0)
+                                return r;
+
+                        /* Allow user services to run, even if the
+                         * home directory is missing */
+                        ec->working_directory_missing_ok = true;
+                }
+
+                if (ec->private_devices)
+                        ec->capability_bounding_set &= ~((UINT64_C(1) << CAP_MKNOD) | (UINT64_C(1) << CAP_SYS_RAWIO));
+
+                if (ec->protect_kernel_modules)
+                        ec->capability_bounding_set &= ~(UINT64_C(1) << CAP_SYS_MODULE);
+
+                if (ec->dynamic_user) {
+                        if (!ec->user) {
+                                r = user_from_unit_name(u, &ec->user);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (!ec->group) {
+                                ec->group = strdup(ec->user);
+                                if (!ec->group)
+                                        return -ENOMEM;
+                        }
+
+                        /* If the dynamic user option is on, let's make sure that the unit can't leave its UID/GID
+                         * around in the file system or on IPC objects. Hence enforce a strict sandbox. */
+
+                        ec->private_tmp = true;
+                        ec->remove_ipc = true;
+                        ec->protect_system = PROTECT_SYSTEM_STRICT;
+                        if (ec->protect_home == PROTECT_HOME_NO)
+                                ec->protect_home = PROTECT_HOME_READ_ONLY;
+                }
+        }
+
+        cc = unit_get_cgroup_context(u);
+        if (cc && ec) {
+
+                if (ec->private_devices &&
+                    cc->device_policy == CGROUP_AUTO)
+                        cc->device_policy = CGROUP_CLOSED;
+
+                if (ec->root_image &&
+                    (cc->device_policy != CGROUP_AUTO || cc->device_allow)) {
+
+                        /* When RootImage= is specified, the following devices are touched. */
+                        r = cgroup_add_device_allow(cc, "/dev/loop-control", "rw");
+                        if (r < 0)
+                                return r;
+
+                        r = cgroup_add_device_allow(cc, "block-loop", "rwm");
+                        if (r < 0)
+                                return r;
+
+                        r = cgroup_add_device_allow(cc, "block-blkext", "rwm");
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        return 0;
+}
+
+ExecContext *unit_get_exec_context(Unit *u) {
+        size_t offset;
+        assert(u);
+
+        if (u->type < 0)
+                return NULL;
+
+        offset = UNIT_VTABLE(u)->exec_context_offset;
+        if (offset <= 0)
+                return NULL;
+
+        return (ExecContext*) ((uint8_t*) u + offset);
+}
+
+KillContext *unit_get_kill_context(Unit *u) {
+        size_t offset;
+        assert(u);
+
+        if (u->type < 0)
+                return NULL;
+
+        offset = UNIT_VTABLE(u)->kill_context_offset;
+        if (offset <= 0)
+                return NULL;
+
+        return (KillContext*) ((uint8_t*) u + offset);
+}
+
+CGroupContext *unit_get_cgroup_context(Unit *u) {
+        size_t offset;
+
+        if (u->type < 0)
+                return NULL;
+
+        offset = UNIT_VTABLE(u)->cgroup_context_offset;
+        if (offset <= 0)
+                return NULL;
+
+        return (CGroupContext*) ((uint8_t*) u + offset);
+}
+
+ExecRuntime *unit_get_exec_runtime(Unit *u) {
+        size_t offset;
+
+        if (u->type < 0)
+                return NULL;
+
+        offset = UNIT_VTABLE(u)->exec_runtime_offset;
+        if (offset <= 0)
+                return NULL;
+
+        return *(ExecRuntime**) ((uint8_t*) u + offset);
+}
+
+static const char* unit_drop_in_dir(Unit *u, UnitWriteFlags flags) {
+        assert(u);
+
+        if (UNIT_WRITE_FLAGS_NOOP(flags))
+                return NULL;
+
+        if (u->transient) /* Redirect drop-ins for transient units always into the transient directory. */
+                return u->manager->lookup_paths.transient;
+
+        if (flags & UNIT_PERSISTENT)
+                return u->manager->lookup_paths.persistent_control;
+
+        if (flags & UNIT_RUNTIME)
+                return u->manager->lookup_paths.runtime_control;
+
+        return NULL;
+}
+
+char* unit_escape_setting(const char *s, UnitWriteFlags flags, char **buf) {
+        char *ret = NULL;
+
+        if (!s)
+                return NULL;
+
+        /* Escapes the input string as requested. Returns the escaped string. If 'buf' is specified then the allocated
+         * return buffer pointer is also written to *buf, except if no escaping was necessary, in which case *buf is
+         * set to NULL, and the input pointer is returned as-is. This means the return value always contains a properly
+         * escaped version, but *buf when passed only contains a pointer if an allocation was necessary. If *buf is
+         * not specified, then the return value always needs to be freed. Callers can use this to optimize memory
+         * allocations. */
+
+        if (flags & UNIT_ESCAPE_SPECIFIERS) {
+                ret = specifier_escape(s);
+                if (!ret)
+                        return NULL;
+
+                s = ret;
+        }
+
+        if (flags & UNIT_ESCAPE_C) {
+                char *a;
+
+                a = cescape(s);
+                free(ret);
+                if (!a)
+                        return NULL;
+
+                ret = a;
+        }
+
+        if (buf) {
+                *buf = ret;
+                return ret ?: (char*) s;
+        }
+
+        return ret ?: strdup(s);
+}
+
+char* unit_concat_strv(char **l, UnitWriteFlags flags) {
+        _cleanup_free_ char *result = NULL;
+        size_t n = 0, allocated = 0;
+        char **i;
+
+        /* Takes a list of strings, escapes them, and concatenates them. This may be used to format command lines in a
+         * way suitable for ExecStart= stanzas */
+
+        STRV_FOREACH(i, l) {
+                _cleanup_free_ char *buf = NULL;
+                const char *p;
+                size_t a;
+                char *q;
+
+                p = unit_escape_setting(*i, flags, &buf);
+                if (!p)
+                        return NULL;
+
+                a = (n > 0) + 1 + strlen(p) + 1; /* separating space + " + entry + " */
+                if (!GREEDY_REALLOC(result, allocated, n + a + 1))
+                        return NULL;
+
+                q = result + n;
+                if (n > 0)
+                        *(q++) = ' ';
+
+                *(q++) = '"';
+                q = stpcpy(q, p);
+                *(q++) = '"';
+
+                n += a;
+        }
+
+        if (!GREEDY_REALLOC(result, allocated, n + 1))
+                return NULL;
+
+        result[n] = 0;
+
+        return TAKE_PTR(result);
+}
+
+int unit_write_setting(Unit *u, UnitWriteFlags flags, const char *name, const char *data) {
+        _cleanup_free_ char *p = NULL, *q = NULL, *escaped = NULL;
+        const char *dir, *wrapped;
+        int r;
+
+        assert(u);
+        assert(name);
+        assert(data);
+
+        if (UNIT_WRITE_FLAGS_NOOP(flags))
+                return 0;
+
+        data = unit_escape_setting(data, flags, &escaped);
+        if (!data)
+                return -ENOMEM;
+
+        /* Prefix the section header. If we are writing this out as transient file, then let's suppress this if the
+         * previous section header is the same */
+
+        if (flags & UNIT_PRIVATE) {
+                if (!UNIT_VTABLE(u)->private_section)
+                        return -EINVAL;
+
+                if (!u->transient_file || u->last_section_private < 0)
+                        data = strjoina("[", UNIT_VTABLE(u)->private_section, "]\n", data);
+                else if (u->last_section_private == 0)
+                        data = strjoina("\n[", UNIT_VTABLE(u)->private_section, "]\n", data);
+        } else {
+                if (!u->transient_file || u->last_section_private < 0)
+                        data = strjoina("[Unit]\n", data);
+                else if (u->last_section_private > 0)
+                        data = strjoina("\n[Unit]\n", data);
+        }
+
+        if (u->transient_file) {
+                /* When this is a transient unit file in creation, then let's not create a new drop-in but instead
+                 * write to the transient unit file. */
+                fputs(data, u->transient_file);
+
+                if (!endswith(data, "\n"))
+                        fputc('\n', u->transient_file);
+
+                /* Remember which section we wrote this entry to */
+                u->last_section_private = !!(flags & UNIT_PRIVATE);
+                return 0;
+        }
+
+        dir = unit_drop_in_dir(u, flags);
+        if (!dir)
+                return -EINVAL;
+
+        wrapped = strjoina("# This is a drop-in unit file extension, created via \"systemctl set-property\"\n"
+                           "# or an equivalent operation. Do not edit.\n",
+                           data,
+                           "\n");
+
+        r = drop_in_file(dir, u->id, 50, name, &p, &q);
+        if (r < 0)
+                return r;
+
+        (void) mkdir_p_label(p, 0755);
+        r = write_string_file_atomic_label(q, wrapped);
+        if (r < 0)
+                return r;
+
+        r = strv_push(&u->dropin_paths, q);
+        if (r < 0)
+                return r;
+        q = NULL;
+
+        strv_uniq(u->dropin_paths);
+
+        u->dropin_mtime = now(CLOCK_REALTIME);
+
+        return 0;
+}
+
+int unit_write_settingf(Unit *u, UnitWriteFlags flags, const char *name, const char *format, ...) {
+        _cleanup_free_ char *p = NULL;
+        va_list ap;
+        int r;
+
+        assert(u);
+        assert(name);
+        assert(format);
+
+        if (UNIT_WRITE_FLAGS_NOOP(flags))
+                return 0;
+
+        va_start(ap, format);
+        r = vasprintf(&p, format, ap);
+        va_end(ap);
+
+        if (r < 0)
+                return -ENOMEM;
+
+        return unit_write_setting(u, flags, name, p);
+}
+
+int unit_make_transient(Unit *u) {
+        _cleanup_free_ char *path = NULL;
+        FILE *f;
+
+        assert(u);
+
+        if (!UNIT_VTABLE(u)->can_transient)
+                return -EOPNOTSUPP;
+
+        (void) mkdir_p_label(u->manager->lookup_paths.transient, 0755);
+
+        path = strjoin(u->manager->lookup_paths.transient, "/", u->id);
+        if (!path)
+                return -ENOMEM;
+
+        /* Let's open the file we'll write the transient settings into. This file is kept open as long as we are
+         * creating the transient, and is closed in unit_load(), as soon as we start loading the file. */
+
+        RUN_WITH_UMASK(0022) {
+                f = fopen(path, "we");
+                if (!f)
+                        return -errno;
+        }
+
+        safe_fclose(u->transient_file);
+        u->transient_file = f;
+
+        free_and_replace(u->fragment_path, path);
+
+        u->source_path = mfree(u->source_path);
+        u->dropin_paths = strv_free(u->dropin_paths);
+        u->fragment_mtime = u->source_mtime = u->dropin_mtime = 0;
+
+        u->load_state = UNIT_STUB;
+        u->load_error = 0;
+        u->transient = true;
+
+        unit_add_to_dbus_queue(u);
+        unit_add_to_gc_queue(u);
+
+        fputs("# This is a transient unit file, created programmatically via the systemd API. Do not edit.\n",
+              u->transient_file);
+
+        return 0;
+}
+
+static void log_kill(pid_t pid, int sig, void *userdata) {
+        _cleanup_free_ char *comm = NULL;
+
+        (void) get_process_comm(pid, &comm);
+
+        /* Don't log about processes marked with brackets, under the assumption that these are temporary processes
+           only, like for example systemd's own PAM stub process. */
+        if (comm && comm[0] == '(')
+                return;
+
+        log_unit_notice(userdata,
+                        "Killing process " PID_FMT " (%s) with signal SIG%s.",
+                        pid,
+                        strna(comm),
+                        signal_to_string(sig));
+}
+
+static int operation_to_signal(KillContext *c, KillOperation k) {
+        assert(c);
+
+        switch (k) {
+
+        case KILL_TERMINATE:
+        case KILL_TERMINATE_AND_LOG:
+                return c->kill_signal;
+
+        case KILL_KILL:
+                return c->final_kill_signal;
+
+        case KILL_WATCHDOG:
+                return c->watchdog_signal;
+
+        default:
+                assert_not_reached("KillOperation unknown");
+        }
+}
+
+int unit_kill_context(
+                Unit *u,
+                KillContext *c,
+                KillOperation k,
+                pid_t main_pid,
+                pid_t control_pid,
+                bool main_pid_alien) {
+
+        bool wait_for_exit = false, send_sighup;
+        cg_kill_log_func_t log_func = NULL;
+        int sig, r;
+
+        assert(u);
+        assert(c);
+
+        /* Kill the processes belonging to this unit, in preparation for shutting the unit down.
+         * Returns > 0 if we killed something worth waiting for, 0 otherwise. */
+
+        if (c->kill_mode == KILL_NONE)
+                return 0;
+
+        sig = operation_to_signal(c, k);
+
+        send_sighup =
+                c->send_sighup &&
+                IN_SET(k, KILL_TERMINATE, KILL_TERMINATE_AND_LOG) &&
+                sig != SIGHUP;
+
+        if (k != KILL_TERMINATE || IN_SET(sig, SIGKILL, SIGABRT))
+                log_func = log_kill;
+
+        if (main_pid > 0) {
+                if (log_func)
+                        log_func(main_pid, sig, u);
+
+                r = kill_and_sigcont(main_pid, sig);
+                if (r < 0 && r != -ESRCH) {
+                        _cleanup_free_ char *comm = NULL;
+                        (void) get_process_comm(main_pid, &comm);
+
+                        log_unit_warning_errno(u, r, "Failed to kill main process " PID_FMT " (%s), ignoring: %m", main_pid, strna(comm));
+                } else {
+                        if (!main_pid_alien)
+                                wait_for_exit = true;
+
+                        if (r != -ESRCH && send_sighup)
+                                (void) kill(main_pid, SIGHUP);
+                }
+        }
+
+        if (control_pid > 0) {
+                if (log_func)
+                        log_func(control_pid, sig, u);
+
+                r = kill_and_sigcont(control_pid, sig);
+                if (r < 0 && r != -ESRCH) {
+                        _cleanup_free_ char *comm = NULL;
+                        (void) get_process_comm(control_pid, &comm);
+
+                        log_unit_warning_errno(u, r, "Failed to kill control process " PID_FMT " (%s), ignoring: %m", control_pid, strna(comm));
+                } else {
+                        wait_for_exit = true;
+
+                        if (r != -ESRCH && send_sighup)
+                                (void) kill(control_pid, SIGHUP);
+                }
+        }
+
+        if (u->cgroup_path &&
+            (c->kill_mode == KILL_CONTROL_GROUP || (c->kill_mode == KILL_MIXED && k == KILL_KILL))) {
+                _cleanup_set_free_ Set *pid_set = NULL;
+
+                /* Exclude the main/control pids from being killed via the cgroup */
+                pid_set = unit_pid_set(main_pid, control_pid);
+                if (!pid_set)
+                        return -ENOMEM;
+
+                r = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path,
+                                      sig,
+                                      CGROUP_SIGCONT|CGROUP_IGNORE_SELF,
+                                      pid_set,
+                                      log_func, u);
+                if (r < 0) {
+                        if (!IN_SET(r, -EAGAIN, -ESRCH, -ENOENT))
+                                log_unit_warning_errno(u, r, "Failed to kill control group %s, ignoring: %m", u->cgroup_path);
+
+                } else if (r > 0) {
+
+                        /* FIXME: For now, on the legacy hierarchy, we will not wait for the cgroup members to die if
+                         * we are running in a container or if this is a delegation unit, simply because cgroup
+                         * notification is unreliable in these cases. It doesn't work at all in containers, and outside
+                         * of containers it can be confused easily by left-over directories in the cgroup — which
+                         * however should not exist in non-delegated units. On the unified hierarchy that's different,
+                         * there we get proper events. Hence rely on them. */
+
+                        if (cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER) > 0 ||
+                            (detect_container() == 0 && !unit_cgroup_delegate(u)))
+                                wait_for_exit = true;
+
+                        if (send_sighup) {
+                                set_free(pid_set);
+
+                                pid_set = unit_pid_set(main_pid, control_pid);
+                                if (!pid_set)
+                                        return -ENOMEM;
+
+                                cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path,
+                                                  SIGHUP,
+                                                  CGROUP_IGNORE_SELF,
+                                                  pid_set,
+                                                  NULL, NULL);
+                        }
+                }
+        }
+
+        return wait_for_exit;
+}
+
+int unit_require_mounts_for(Unit *u, const char *path, UnitDependencyMask mask) {
+        _cleanup_free_ char *p = NULL;
+        UnitDependencyInfo di;
+        int r;
+
+        assert(u);
+        assert(path);
+
+        /* Registers a unit for requiring a certain path and all its prefixes. We keep a hashtable of these paths in
+         * the unit (from the path to the UnitDependencyInfo structure indicating how to the dependency came to
+         * be). However, we build a prefix table for all possible prefixes so that new appearing mount units can easily
+         * determine which units to make themselves a dependency of. */
+
+        if (!path_is_absolute(path))
+                return -EINVAL;
+
+        r = hashmap_ensure_allocated(&u->requires_mounts_for, &path_hash_ops);
+        if (r < 0)
+                return r;
+
+        p = strdup(path);
+        if (!p)
+                return -ENOMEM;
+
+        path = path_simplify(p, false);
+
+        if (!path_is_normalized(path))
+                return -EPERM;
+
+        if (hashmap_contains(u->requires_mounts_for, path))
+                return 0;
+
+        di = (UnitDependencyInfo) {
+                .origin_mask = mask
+        };
+
+        r = hashmap_put(u->requires_mounts_for, path, di.data);
+        if (r < 0)
+                return r;
+        p = NULL;
+
+        char prefix[strlen(path) + 1];
+        PATH_FOREACH_PREFIX_MORE(prefix, path) {
+                Set *x;
+
+                x = hashmap_get(u->manager->units_requiring_mounts_for, prefix);
+                if (!x) {
+                        _cleanup_free_ char *q = NULL;
+
+                        r = hashmap_ensure_allocated(&u->manager->units_requiring_mounts_for, &path_hash_ops);
+                        if (r < 0)
+                                return r;
+
+                        q = strdup(prefix);
+                        if (!q)
+                                return -ENOMEM;
+
+                        x = set_new(NULL);
+                        if (!x)
+                                return -ENOMEM;
+
+                        r = hashmap_put(u->manager->units_requiring_mounts_for, q, x);
+                        if (r < 0) {
+                                set_free(x);
+                                return r;
+                        }
+                        q = NULL;
+                }
+
+                r = set_put(x, u);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int unit_setup_exec_runtime(Unit *u) {
+        ExecRuntime **rt;
+        size_t offset;
+        Unit *other;
+        Iterator i;
+        void *v;
+        int r;
+
+        offset = UNIT_VTABLE(u)->exec_runtime_offset;
+        assert(offset > 0);
+
+        /* Check if there already is an ExecRuntime for this unit? */
+        rt = (ExecRuntime**) ((uint8_t*) u + offset);
+        if (*rt)
+                return 0;
+
+        /* Try to get it from somebody else */
+        HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_JOINS_NAMESPACE_OF], i) {
+                r = exec_runtime_acquire(u->manager, NULL, other->id, false, rt);
+                if (r == 1)
+                        return 1;
+        }
+
+        return exec_runtime_acquire(u->manager, unit_get_exec_context(u), u->id, true, rt);
+}
+
+int unit_setup_dynamic_creds(Unit *u) {
+        ExecContext *ec;
+        DynamicCreds *dcreds;
+        size_t offset;
+
+        assert(u);
+
+        offset = UNIT_VTABLE(u)->dynamic_creds_offset;
+        assert(offset > 0);
+        dcreds = (DynamicCreds*) ((uint8_t*) u + offset);
+
+        ec = unit_get_exec_context(u);
+        assert(ec);
+
+        if (!ec->dynamic_user)
+                return 0;
+
+        return dynamic_creds_acquire(dcreds, u->manager, ec->user, ec->group);
+}
+
+bool unit_type_supported(UnitType t) {
+        if (_unlikely_(t < 0))
+                return false;
+        if (_unlikely_(t >= _UNIT_TYPE_MAX))
+                return false;
+
+        if (!unit_vtable[t]->supported)
+                return true;
+
+        return unit_vtable[t]->supported();
+}
+
+void unit_warn_if_dir_nonempty(Unit *u, const char* where) {
+        int r;
+
+        assert(u);
+        assert(where);
+
+        r = dir_is_empty(where);
+        if (r > 0 || r == -ENOTDIR)
+                return;
+        if (r < 0) {
+                log_unit_warning_errno(u, r, "Failed to check directory %s: %m", where);
+                return;
+        }
+
+        log_struct(LOG_NOTICE,
+                   "MESSAGE_ID=" SD_MESSAGE_OVERMOUNTING_STR,
+                   LOG_UNIT_ID(u),
+                   LOG_UNIT_INVOCATION_ID(u),
+                   LOG_UNIT_MESSAGE(u, "Directory %s to mount over is not empty, mounting anyway.", where),
+                   "WHERE=%s", where);
+}
+
+int unit_fail_if_noncanonical(Unit *u, const char* where) {
+        _cleanup_free_ char *canonical_where = NULL;
+        int r;
+
+        assert(u);
+        assert(where);
+
+        r = chase_symlinks(where, NULL, CHASE_NONEXISTENT, &canonical_where);
+        if (r < 0) {
+                log_unit_debug_errno(u, r, "Failed to check %s for symlinks, ignoring: %m", where);
+                return 0;
+        }
+
+        /* We will happily ignore a trailing slash (or any redundant slashes) */
+        if (path_equal(where, canonical_where))
+                return 0;
+
+        /* No need to mention "." or "..", they would already have been rejected by unit_name_from_path() */
+        log_struct(LOG_ERR,
+                   "MESSAGE_ID=" SD_MESSAGE_OVERMOUNTING_STR,
+                   LOG_UNIT_ID(u),
+                   LOG_UNIT_INVOCATION_ID(u),
+                   LOG_UNIT_MESSAGE(u, "Mount path %s is not canonical (contains a symlink).", where),
+                   "WHERE=%s", where);
+
+        return -ELOOP;
+}
+
+bool unit_is_pristine(Unit *u) {
+        assert(u);
+
+        /* Check if the unit already exists or is already around,
+         * in a number of different ways. Note that to cater for unit
+         * types such as slice, we are generally fine with units that
+         * are marked UNIT_LOADED even though nothing was actually
+         * loaded, as those unit types don't require a file on disk. */
+
+        return !(!IN_SET(u->load_state, UNIT_NOT_FOUND, UNIT_LOADED) ||
+                 u->fragment_path ||
+                 u->source_path ||
+                 !strv_isempty(u->dropin_paths) ||
+                 u->job ||
+                 u->merged_into);
+}
+
+pid_t unit_control_pid(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->control_pid)
+                return UNIT_VTABLE(u)->control_pid(u);
+
+        return 0;
+}
+
+pid_t unit_main_pid(Unit *u) {
+        assert(u);
+
+        if (UNIT_VTABLE(u)->main_pid)
+                return UNIT_VTABLE(u)->main_pid(u);
+
+        return 0;
+}
+
+static void unit_unref_uid_internal(
+                Unit *u,
+                uid_t *ref_uid,
+                bool destroy_now,
+                void (*_manager_unref_uid)(Manager *m, uid_t uid, bool destroy_now)) {
+
+        assert(u);
+        assert(ref_uid);
+        assert(_manager_unref_uid);
+
+        /* Generic implementation of both unit_unref_uid() and unit_unref_gid(), under the assumption that uid_t and
+         * gid_t are actually the same time, with the same validity rules.
+         *
+         * Drops a reference to UID/GID from a unit. */
+
+        assert_cc(sizeof(uid_t) == sizeof(gid_t));
+        assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+        if (!uid_is_valid(*ref_uid))
+                return;
+
+        _manager_unref_uid(u->manager, *ref_uid, destroy_now);
+        *ref_uid = UID_INVALID;
+}
+
+void unit_unref_uid(Unit *u, bool destroy_now) {
+        unit_unref_uid_internal(u, &u->ref_uid, destroy_now, manager_unref_uid);
+}
+
+void unit_unref_gid(Unit *u, bool destroy_now) {
+        unit_unref_uid_internal(u, (uid_t*) &u->ref_gid, destroy_now, manager_unref_gid);
+}
+
+static int unit_ref_uid_internal(
+                Unit *u,
+                uid_t *ref_uid,
+                uid_t uid,
+                bool clean_ipc,
+                int (*_manager_ref_uid)(Manager *m, uid_t uid, bool clean_ipc)) {
+
+        int r;
+
+        assert(u);
+        assert(ref_uid);
+        assert(uid_is_valid(uid));
+        assert(_manager_ref_uid);
+
+        /* Generic implementation of both unit_ref_uid() and unit_ref_guid(), under the assumption that uid_t and gid_t
+         * are actually the same type, and have the same validity rules.
+         *
+         * Adds a reference on a specific UID/GID to this unit. Each unit referencing the same UID/GID maintains a
+         * reference so that we can destroy the UID/GID's IPC resources as soon as this is requested and the counter
+         * drops to zero. */
+
+        assert_cc(sizeof(uid_t) == sizeof(gid_t));
+        assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+        if (*ref_uid == uid)
+                return 0;
+
+        if (uid_is_valid(*ref_uid)) /* Already set? */
+                return -EBUSY;
+
+        r = _manager_ref_uid(u->manager, uid, clean_ipc);
+        if (r < 0)
+                return r;
+
+        *ref_uid = uid;
+        return 1;
+}
+
+int unit_ref_uid(Unit *u, uid_t uid, bool clean_ipc) {
+        return unit_ref_uid_internal(u, &u->ref_uid, uid, clean_ipc, manager_ref_uid);
+}
+
+int unit_ref_gid(Unit *u, gid_t gid, bool clean_ipc) {
+        return unit_ref_uid_internal(u, (uid_t*) &u->ref_gid, (uid_t) gid, clean_ipc, manager_ref_gid);
+}
+
+static int unit_ref_uid_gid_internal(Unit *u, uid_t uid, gid_t gid, bool clean_ipc) {
+        int r = 0, q = 0;
+
+        assert(u);
+
+        /* Reference both a UID and a GID in one go. Either references both, or neither. */
+
+        if (uid_is_valid(uid)) {
+                r = unit_ref_uid(u, uid, clean_ipc);
+                if (r < 0)
+                        return r;
+        }
+
+        if (gid_is_valid(gid)) {
+                q = unit_ref_gid(u, gid, clean_ipc);
+                if (q < 0) {
+                        if (r > 0)
+                                unit_unref_uid(u, false);
+
+                        return q;
+                }
+        }
+
+        return r > 0 || q > 0;
+}
+
+int unit_ref_uid_gid(Unit *u, uid_t uid, gid_t gid) {
+        ExecContext *c;
+        int r;
+
+        assert(u);
+
+        c = unit_get_exec_context(u);
+
+        r = unit_ref_uid_gid_internal(u, uid, gid, c ? c->remove_ipc : false);
+        if (r < 0)
+                return log_unit_warning_errno(u, r, "Couldn't add UID/GID reference to unit, proceeding without: %m");
+
+        return r;
+}
+
+void unit_unref_uid_gid(Unit *u, bool destroy_now) {
+        assert(u);
+
+        unit_unref_uid(u, destroy_now);
+        unit_unref_gid(u, destroy_now);
+}
+
+void unit_notify_user_lookup(Unit *u, uid_t uid, gid_t gid) {
+        int r;
+
+        assert(u);
+
+        /* This is invoked whenever one of the forked off processes let's us know the UID/GID its user name/group names
+         * resolved to. We keep track of which UID/GID is currently assigned in order to be able to destroy its IPC
+         * objects when no service references the UID/GID anymore. */
+
+        r = unit_ref_uid_gid(u, uid, gid);
+        if (r > 0)
+                unit_add_to_dbus_queue(u);
+}
+
+int unit_set_invocation_id(Unit *u, sd_id128_t id) {
+        int r;
+
+        assert(u);
+
+        /* Set the invocation ID for this unit. If we cannot, this will not roll back, but reset the whole thing. */
+
+        if (sd_id128_equal(u->invocation_id, id))
+                return 0;
+
+        if (!sd_id128_is_null(u->invocation_id))
+                (void) hashmap_remove_value(u->manager->units_by_invocation_id, &u->invocation_id, u);
+
+        if (sd_id128_is_null(id)) {
+                r = 0;
+                goto reset;
+        }
+
+        r = hashmap_ensure_allocated(&u->manager->units_by_invocation_id, &id128_hash_ops);
+        if (r < 0)
+                goto reset;
+
+        u->invocation_id = id;
+        sd_id128_to_string(id, u->invocation_id_string);
+
+        r = hashmap_put(u->manager->units_by_invocation_id, &u->invocation_id, u);
+        if (r < 0)
+                goto reset;
+
+        return 0;
+
+reset:
+        u->invocation_id = SD_ID128_NULL;
+        u->invocation_id_string[0] = 0;
+        return r;
+}
+
+int unit_acquire_invocation_id(Unit *u) {
+        sd_id128_t id;
+        int r;
+
+        assert(u);
+
+        r = sd_id128_randomize(&id);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "Failed to generate invocation ID for unit: %m");
+
+        r = unit_set_invocation_id(u, id);
+        if (r < 0)
+                return log_unit_error_errno(u, r, "Failed to set invocation ID for unit: %m");
+
+        unit_add_to_dbus_queue(u);
+        return 0;
+}
+
+int unit_set_exec_params(Unit *u, ExecParameters *p) {
+        int r;
+
+        assert(u);
+        assert(p);
+
+        /* Copy parameters from manager */
+        r = manager_get_effective_environment(u->manager, &p->environment);
+        if (r < 0)
+                return r;
+
+        p->confirm_spawn = manager_get_confirm_spawn(u->manager);
+        p->cgroup_supported = u->manager->cgroup_supported;
+        p->prefix = u->manager->prefix;
+        SET_FLAG(p->flags, EXEC_PASS_LOG_UNIT|EXEC_CHOWN_DIRECTORIES, MANAGER_IS_SYSTEM(u->manager));
+
+        /* Copy paramaters from unit */
+        p->cgroup_path = u->cgroup_path;
+        SET_FLAG(p->flags, EXEC_CGROUP_DELEGATE, unit_cgroup_delegate(u));
+
+        return 0;
+}
+
+int unit_fork_helper_process(Unit *u, const char *name, pid_t *ret) {
+        int r;
+
+        assert(u);
+        assert(ret);
+
+        /* Forks off a helper process and makes sure it is a member of the unit's cgroup. Returns == 0 in the child,
+         * and > 0 in the parent. The pid parameter is always filled in with the child's PID. */
+
+        (void) unit_realize_cgroup(u);
+
+        r = safe_fork(name, FORK_REOPEN_LOG, ret);
+        if (r != 0)
+                return r;
+
+        (void) default_signals(SIGNALS_CRASH_HANDLER, SIGNALS_IGNORE, -1);
+        (void) ignore_signals(SIGPIPE, -1);
+
+        (void) prctl(PR_SET_PDEATHSIG, SIGTERM);
+
+        if (u->cgroup_path) {
+                r = cg_attach_everywhere(u->manager->cgroup_supported, u->cgroup_path, 0, NULL, NULL);
+                if (r < 0) {
+                        log_unit_error_errno(u, r, "Failed to join unit cgroup %s: %m", u->cgroup_path);
+                        _exit(EXIT_CGROUP);
+                }
+        }
+
+        return 0;
+}
+
+static void unit_update_dependency_mask(Unit *u, UnitDependency d, Unit *other, UnitDependencyInfo di) {
+        assert(u);
+        assert(d >= 0);
+        assert(d < _UNIT_DEPENDENCY_MAX);
+        assert(other);
+
+        if (di.origin_mask == 0 && di.destination_mask == 0) {
+                /* No bit set anymore, let's drop the whole entry */
+                assert_se(hashmap_remove(u->dependencies[d], other));
+                log_unit_debug(u, "%s lost dependency %s=%s", u->id, unit_dependency_to_string(d), other->id);
+        } else
+                /* Mask was reduced, let's update the entry */
+                assert_se(hashmap_update(u->dependencies[d], other, di.data) == 0);
+}
+
+void unit_remove_dependencies(Unit *u, UnitDependencyMask mask) {
+        UnitDependency d;
+
+        assert(u);
+
+        /* Removes all dependencies u has on other units marked for ownership by 'mask'. */
+
+        if (mask == 0)
+                return;
+
+        for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
+                bool done;
+
+                do {
+                        UnitDependencyInfo di;
+                        Unit *other;
+                        Iterator i;
+
+                        done = true;
+
+                        HASHMAP_FOREACH_KEY(di.data, other, u->dependencies[d], i) {
+                                UnitDependency q;
+
+                                if ((di.origin_mask & ~mask) == di.origin_mask)
+                                        continue;
+                                di.origin_mask &= ~mask;
+                                unit_update_dependency_mask(u, d, other, di);
+
+                                /* We updated the dependency from our unit to the other unit now. But most dependencies
+                                 * imply a reverse dependency. Hence, let's delete that one too. For that we go through
+                                 * all dependency types on the other unit and delete all those which point to us and
+                                 * have the right mask set. */
+
+                                for (q = 0; q < _UNIT_DEPENDENCY_MAX; q++) {
+                                        UnitDependencyInfo dj;
+
+                                        dj.data = hashmap_get(other->dependencies[q], u);
+                                        if ((dj.destination_mask & ~mask) == dj.destination_mask)
+                                                continue;
+                                        dj.destination_mask &= ~mask;
+
+                                        unit_update_dependency_mask(other, q, u, dj);
+                                }
+
+                                unit_add_to_gc_queue(other);
+
+                                done = false;
+                                break;
+                        }
+
+                } while (!done);
+        }
+}
+
+static int unit_export_invocation_id(Unit *u) {
+        const char *p;
+        int r;
+
+        assert(u);
+
+        if (u->exported_invocation_id)
+                return 0;
+
+        if (sd_id128_is_null(u->invocation_id))
+                return 0;
+
+        p = strjoina("/run/systemd/units/invocation:", u->id);
+        r = symlink_atomic(u->invocation_id_string, p);
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Failed to create invocation ID symlink %s: %m", p);
+
+        u->exported_invocation_id = true;
+        return 0;
+}
+
+static int unit_export_log_level_max(Unit *u, const ExecContext *c) {
+        const char *p;
+        char buf[2];
+        int r;
+
+        assert(u);
+        assert(c);
+
+        if (u->exported_log_level_max)
+                return 0;
+
+        if (c->log_level_max < 0)
+                return 0;
+
+        assert(c->log_level_max <= 7);
+
+        buf[0] = '0' + c->log_level_max;
+        buf[1] = 0;
+
+        p = strjoina("/run/systemd/units/log-level-max:", u->id);
+        r = symlink_atomic(buf, p);
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Failed to create maximum log level symlink %s: %m", p);
+
+        u->exported_log_level_max = true;
+        return 0;
+}
+
+static int unit_export_log_extra_fields(Unit *u, const ExecContext *c) {
+        _cleanup_close_ int fd = -1;
+        struct iovec *iovec;
+        const char *p;
+        char *pattern;
+        le64_t *sizes;
+        ssize_t n;
+        size_t i;
+        int r;
+
+        if (u->exported_log_extra_fields)
+                return 0;
+
+        if (c->n_log_extra_fields <= 0)
+                return 0;
+
+        sizes = newa(le64_t, c->n_log_extra_fields);
+        iovec = newa(struct iovec, c->n_log_extra_fields * 2);
+
+        for (i = 0; i < c->n_log_extra_fields; i++) {
+                sizes[i] = htole64(c->log_extra_fields[i].iov_len);
+
+                iovec[i*2] = IOVEC_MAKE(sizes + i, sizeof(le64_t));
+                iovec[i*2+1] = c->log_extra_fields[i];
+        }
+
+        p = strjoina("/run/systemd/units/log-extra-fields:", u->id);
+        pattern = strjoina(p, ".XXXXXX");
+
+        fd = mkostemp_safe(pattern);
+        if (fd < 0)
+                return log_unit_debug_errno(u, fd, "Failed to create extra fields file %s: %m", p);
+
+        n = writev(fd, iovec, c->n_log_extra_fields*2);
+        if (n < 0) {
+                r = log_unit_debug_errno(u, errno, "Failed to write extra fields: %m");
+                goto fail;
+        }
+
+        (void) fchmod(fd, 0644);
+
+        if (rename(pattern, p) < 0) {
+                r = log_unit_debug_errno(u, errno, "Failed to rename extra fields file: %m");
+                goto fail;
+        }
+
+        u->exported_log_extra_fields = true;
+        return 0;
+
+fail:
+        (void) unlink(pattern);
+        return r;
+}
+
+static int unit_export_log_rate_limit_interval(Unit *u, const ExecContext *c) {
+        _cleanup_free_ char *buf = NULL;
+        const char *p;
+        int r;
+
+        assert(u);
+        assert(c);
+
+        if (u->exported_log_rate_limit_interval)
+                return 0;
+
+        if (c->log_rate_limit_interval_usec == 0)
+                return 0;
+
+        p = strjoina("/run/systemd/units/log-rate-limit-interval:", u->id);
+
+        if (asprintf(&buf, "%" PRIu64, c->log_rate_limit_interval_usec) < 0)
+                return log_oom();
+
+        r = symlink_atomic(buf, p);
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Failed to create log rate limit interval symlink %s: %m", p);
+
+        u->exported_log_rate_limit_interval = true;
+        return 0;
+}
+
+static int unit_export_log_rate_limit_burst(Unit *u, const ExecContext *c) {
+        _cleanup_free_ char *buf = NULL;
+        const char *p;
+        int r;
+
+        assert(u);
+        assert(c);
+
+        if (u->exported_log_rate_limit_burst)
+                return 0;
+
+        if (c->log_rate_limit_burst == 0)
+                return 0;
+
+        p = strjoina("/run/systemd/units/log-rate-limit-burst:", u->id);
+
+        if (asprintf(&buf, "%u", c->log_rate_limit_burst) < 0)
+                return log_oom();
+
+        r = symlink_atomic(buf, p);
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Failed to create log rate limit burst symlink %s: %m", p);
+
+        u->exported_log_rate_limit_burst = true;
+        return 0;
+}
+
+void unit_export_state_files(Unit *u) {
+        const ExecContext *c;
+
+        assert(u);
+
+        if (!u->id)
+                return;
+
+        if (!MANAGER_IS_SYSTEM(u->manager))
+                return;
+
+        if (MANAGER_IS_TEST_RUN(u->manager))
+                return;
+
+        /* Exports a couple of unit properties to /run/systemd/units/, so that journald can quickly query this data
+         * from there. Ideally, journald would use IPC to query this, like everybody else, but that's hard, as long as
+         * the IPC system itself and PID 1 also log to the journal.
+         *
+         * Note that these files really shouldn't be considered API for anyone else, as use a runtime file system as
+         * IPC replacement is not compatible with today's world of file system namespaces. However, this doesn't really
+         * apply to communication between the journal and systemd, as we assume that these two daemons live in the same
+         * namespace at least.
+         *
+         * Note that some of the "files" exported here are actually symlinks and not regular files. Symlinks work
+         * better for storing small bits of data, in particular as we can write them with two system calls, and read
+         * them with one. */
+
+        (void) unit_export_invocation_id(u);
+
+        c = unit_get_exec_context(u);
+        if (c) {
+                (void) unit_export_log_level_max(u, c);
+                (void) unit_export_log_extra_fields(u, c);
+                (void) unit_export_log_rate_limit_interval(u, c);
+                (void) unit_export_log_rate_limit_burst(u, c);
+        }
+}
+
+void unit_unlink_state_files(Unit *u) {
+        const char *p;
+
+        assert(u);
+
+        if (!u->id)
+                return;
+
+        if (!MANAGER_IS_SYSTEM(u->manager))
+                return;
+
+        /* Undoes the effect of unit_export_state() */
+
+        if (u->exported_invocation_id) {
+                p = strjoina("/run/systemd/units/invocation:", u->id);
+                (void) unlink(p);
+
+                u->exported_invocation_id = false;
+        }
+
+        if (u->exported_log_level_max) {
+                p = strjoina("/run/systemd/units/log-level-max:", u->id);
+                (void) unlink(p);
+
+                u->exported_log_level_max = false;
+        }
+
+        if (u->exported_log_extra_fields) {
+                p = strjoina("/run/systemd/units/extra-fields:", u->id);
+                (void) unlink(p);
+
+                u->exported_log_extra_fields = false;
+        }
+
+        if (u->exported_log_rate_limit_interval) {
+                p = strjoina("/run/systemd/units/log-rate-limit-interval:", u->id);
+                (void) unlink(p);
+
+                u->exported_log_rate_limit_interval = false;
+        }
+
+        if (u->exported_log_rate_limit_burst) {
+                p = strjoina("/run/systemd/units/log-rate-limit-burst:", u->id);
+                (void) unlink(p);
+
+                u->exported_log_rate_limit_burst = false;
+        }
+}
+
+int unit_prepare_exec(Unit *u) {
+        int r;
+
+        assert(u);
+
+        /* Prepares everything so that we can fork of a process for this unit */
+
+        (void) unit_realize_cgroup(u);
+
+        if (u->reset_accounting) {
+                (void) unit_reset_cpu_accounting(u);
+                (void) unit_reset_ip_accounting(u);
+                u->reset_accounting = false;
+        }
+
+        unit_export_state_files(u);
+
+        r = unit_setup_exec_runtime(u);
+        if (r < 0)
+                return r;
+
+        r = unit_setup_dynamic_creds(u);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static void log_leftover(pid_t pid, int sig, void *userdata) {
+        _cleanup_free_ char *comm = NULL;
+
+        (void) get_process_comm(pid, &comm);
+
+        if (comm && comm[0] == '(') /* Most likely our own helper process (PAM?), ignore */
+                return;
+
+        log_unit_warning(userdata,
+                         "Found left-over process " PID_FMT " (%s) in control group while starting unit. Ignoring.\n"
+                         "This usually indicates unclean termination of a previous run, or service implementation deficiencies.",
+                         pid, strna(comm));
+}
+
+void unit_warn_leftover_processes(Unit *u) {
+        assert(u);
+
+        (void) unit_pick_cgroup_path(u);
+
+        if (!u->cgroup_path)
+                return;
+
+        (void) cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, 0, 0, NULL, log_leftover, u);
+}
+
+bool unit_needs_console(Unit *u) {
+        ExecContext *ec;
+        UnitActiveState state;
+
+        assert(u);
+
+        state = unit_active_state(u);
+
+        if (UNIT_IS_INACTIVE_OR_FAILED(state))
+                return false;
+
+        if (UNIT_VTABLE(u)->needs_console)
+                return UNIT_VTABLE(u)->needs_console(u);
+
+        /* If this unit type doesn't implement this call, let's use a generic fallback implementation: */
+        ec = unit_get_exec_context(u);
+        if (!ec)
+                return false;
+
+        return exec_context_may_touch_console(ec);
+}
+
+const char *unit_label_path(Unit *u) {
+        const char *p;
+
+        /* Returns the file system path to use for MAC access decisions, i.e. the file to read the SELinux label off
+         * when validating access checks. */
+
+        p = u->source_path ?: u->fragment_path;
+        if (!p)
+                return NULL;
+
+        /* If a unit is masked, then don't read the SELinux label of /dev/null, as that really makes no sense */
+        if (path_equal(p, "/dev/null"))
+                return NULL;
+
+        return p;
+}
+
+int unit_pid_attachable(Unit *u, pid_t pid, sd_bus_error *error) {
+        int r;
+
+        assert(u);
+
+        /* Checks whether the specified PID is generally good for attaching, i.e. a valid PID, not our manager itself,
+         * and not a kernel thread either */
+
+        /* First, a simple range check */
+        if (!pid_is_valid(pid))
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Process identifier " PID_FMT " is not valid.", pid);
+
+        /* Some extra safety check */
+        if (pid == 1 || pid == getpid_cached())
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Process " PID_FMT " is a manager process, refusing.", pid);
+
+        /* Don't even begin to bother with kernel threads */
+        r = is_kernel_thread(pid);
+        if (r == -ESRCH)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_UNIX_PROCESS_ID_UNKNOWN, "Process with ID " PID_FMT " does not exist.", pid);
+        if (r < 0)
+                return sd_bus_error_set_errnof(error, r, "Failed to determine whether process " PID_FMT " is a kernel thread: %m", pid);
+        if (r > 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Process " PID_FMT " is a kernel thread, refusing.", pid);
+
+        return 0;
+}
+
+void unit_log_success(Unit *u) {
+        assert(u);
+
+        log_struct(LOG_INFO,
+                   "MESSAGE_ID=" SD_MESSAGE_UNIT_SUCCESS_STR,
+                   LOG_UNIT_ID(u),
+                   LOG_UNIT_INVOCATION_ID(u),
+                   LOG_UNIT_MESSAGE(u, "Succeeded."));
+}
+
+void unit_log_failure(Unit *u, const char *result) {
+        assert(u);
+        assert(result);
+
+        log_struct(LOG_WARNING,
+                   "MESSAGE_ID=" SD_MESSAGE_UNIT_FAILURE_RESULT_STR,
+                   LOG_UNIT_ID(u),
+                   LOG_UNIT_INVOCATION_ID(u),
+                   LOG_UNIT_MESSAGE(u, "Failed with result '%s'.", result),
+                   "UNIT_RESULT=%s", result);
+}
+
+void unit_log_process_exit(
+                Unit *u,
+                int level,
+                const char *kind,
+                const char *command,
+                int code,
+                int status) {
+
+        assert(u);
+        assert(kind);
+
+        if (code != CLD_EXITED)
+                level = LOG_WARNING;
+
+        log_struct(level,
+                   "MESSAGE_ID=" SD_MESSAGE_UNIT_PROCESS_EXIT_STR,
+                   LOG_UNIT_MESSAGE(u, "%s exited, code=%s, status=%i/%s",
+                                    kind,
+                                    sigchld_code_to_string(code), status,
+                                    strna(code == CLD_EXITED
+                                          ? exit_status_to_string(status, EXIT_STATUS_FULL)
+                                          : signal_to_string(status))),
+                   "EXIT_CODE=%s", sigchld_code_to_string(code),
+                   "EXIT_STATUS=%i", status,
+                   "COMMAND=%s", strna(command),
+                   LOG_UNIT_ID(u),
+                   LOG_UNIT_INVOCATION_ID(u));
+}
+
+int unit_exit_status(Unit *u) {
+        assert(u);
+
+        /* Returns the exit status to propagate for the most recent cycle of this unit. Returns a value in the range
+         * 0…255 if there's something to propagate. EOPNOTSUPP if the concept does not apply to this unit type, ENODATA
+         * if no data is currently known (for example because the unit hasn't deactivated yet) and EBADE if the main
+         * service process has exited abnormally (signal/coredump). */
+
+        if (!UNIT_VTABLE(u)->exit_status)
+                return -EOPNOTSUPP;
+
+        return UNIT_VTABLE(u)->exit_status(u);
+}
+
+int unit_failure_action_exit_status(Unit *u) {
+        int r;
+
+        assert(u);
+
+        /* Returns the exit status to propagate on failure, or an error if there's nothing to propagate */
+
+        if (u->failure_action_exit_status >= 0)
+                return u->failure_action_exit_status;
+
+        r = unit_exit_status(u);
+        if (r == -EBADE) /* Exited, but not cleanly (i.e. by signal or such) */
+                return 255;
+
+        return r;
+}
+
+int unit_success_action_exit_status(Unit *u) {
+        int r;
+
+        assert(u);
+
+        /* Returns the exit status to propagate on success, or an error if there's nothing to propagate */
+
+        if (u->success_action_exit_status >= 0)
+                return u->success_action_exit_status;
+
+        r = unit_exit_status(u);
+        if (r == -EBADE) /* Exited, but not cleanly (i.e. by signal or such) */
+                return 255;
+
+        return r;
+}
+
+static const char* const collect_mode_table[_COLLECT_MODE_MAX] = {
+        [COLLECT_INACTIVE] = "inactive",
+        [COLLECT_INACTIVE_OR_FAILED] = "inactive-or-failed",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(collect_mode, CollectMode);