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-rw-r--r--unit.c807
1 files changed, 807 insertions, 0 deletions
diff --git a/unit.c b/unit.c
new file mode 100644
index 0000000000..15401e24fe
--- /dev/null
+++ b/unit.c
@@ -0,0 +1,807 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/poll.h>
+
+#include "set.h"
+#include "unit.h"
+#include "macro.h"
+#include "strv.h"
+#include "load-fragment.h"
+#include "load-dropin.h"
+#include "log.h"
+
+const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX] = {
+ [UNIT_SERVICE] = &service_vtable,
+ [UNIT_TIMER] = &timer_vtable,
+ [UNIT_SOCKET] = &socket_vtable,
+ [UNIT_TARGET] = &target_vtable,
+ [UNIT_DEVICE] = &device_vtable,
+ [UNIT_MOUNT] = &mount_vtable,
+ [UNIT_AUTOMOUNT] = &automount_vtable,
+ [UNIT_SNAPSHOT] = &snapshot_vtable
+};
+
+UnitType unit_name_to_type(const char *n) {
+ UnitType t;
+
+ assert(n);
+
+ for (t = 0; t < _UNIT_TYPE_MAX; t++)
+ if (endswith(n, unit_vtable[t]->suffix))
+ return t;
+
+ return _UNIT_TYPE_INVALID;
+}
+
+#define VALID_CHARS \
+ "0123456789" \
+ "abcdefghijklmnopqrstuvwxyz" \
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+ "-_"
+
+bool unit_name_is_valid(const char *n) {
+ UnitType t;
+ const char *e, *i;
+
+ assert(n);
+
+ if (strlen(n) >= UNIT_NAME_MAX)
+ return false;
+
+ t = unit_name_to_type(n);
+ if (t < 0 || t >= _UNIT_TYPE_MAX)
+ return false;
+
+ if (!(e = strrchr(n, '.')))
+ return false;
+
+ for (i = n; i < e; i++)
+ if (!strchr(VALID_CHARS, *i))
+ return false;
+
+ return true;
+}
+
+char *unit_name_change_suffix(const char *n, const char *suffix) {
+ char *e, *r;
+ size_t a, b;
+
+ assert(n);
+ assert(unit_name_is_valid(n));
+ assert(suffix);
+
+ assert_se(e = strrchr(n, '.'));
+ a = e - n;
+ b = strlen(suffix);
+
+ if (!(r = new(char, a + b + 1)))
+ return NULL;
+
+ memcpy(r, n, a);
+ memcpy(r+a, suffix, b+1);
+
+ return r;
+}
+
+Unit *unit_new(Manager *m) {
+ Unit *u;
+
+ assert(m);
+
+ if (!(u = new0(Unit, 1)))
+ return NULL;
+
+ if (!(u->meta.names = set_new(string_hash_func, string_compare_func))) {
+ free(u);
+ return NULL;
+ }
+
+ u->meta.manager = m;
+ u->meta.type = _UNIT_TYPE_INVALID;
+
+ return u;
+}
+
+int unit_add_name(Unit *u, const char *text) {
+ UnitType t;
+ char *s;
+ int r;
+
+ assert(u);
+ assert(text);
+
+ if (!unit_name_is_valid(text))
+ return -EINVAL;
+
+ if ((t = unit_name_to_type(text)) == _UNIT_TYPE_INVALID)
+ return -EINVAL;
+
+ if (u->meta.type != _UNIT_TYPE_INVALID && t != u->meta.type)
+ return -EINVAL;
+
+ if (!(s = strdup(text)))
+ return -ENOMEM;
+
+ if ((r = set_put(u->meta.names, s)) < 0) {
+ free(s);
+
+ if (r == -EEXIST)
+ return 0;
+
+ return r;
+ }
+
+ if ((r = hashmap_put(u->meta.manager->units, s, u)) < 0) {
+ set_remove(u->meta.names, s);
+ free(s);
+ return r;
+ }
+
+ u->meta.type = t;
+
+ if (!u->meta.id)
+ u->meta.id = s;
+
+ return 0;
+}
+
+void unit_add_to_load_queue(Unit *u) {
+ assert(u);
+
+ if (u->meta.load_state != UNIT_STUB || u->meta.in_load_queue)
+ return;
+
+ LIST_PREPEND(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
+ u->meta.in_load_queue = true;
+}
+
+static void bidi_set_free(Unit *u, Set *s) {
+ Iterator i;
+ Unit *other;
+
+ assert(u);
+
+ /* Frees the set and makes sure we are dropped from the
+ * inverse pointers */
+
+ SET_FOREACH(other, s, i) {
+ UnitDependency d;
+
+ for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+ set_remove(other->meta.dependencies[d], u);
+ }
+
+ set_free(s);
+}
+
+void unit_free(Unit *u) {
+ UnitDependency d;
+ Iterator i;
+ char *t;
+
+ assert(u);
+
+ /* Detach from next 'bigger' objects */
+
+ SET_FOREACH(t, u->meta.names, i)
+ hashmap_remove_value(u->meta.manager->units, t, u);
+
+ if (u->meta.in_load_queue)
+ LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
+
+ if (u->meta.load_state == UNIT_LOADED)
+ if (UNIT_VTABLE(u)->done)
+ UNIT_VTABLE(u)->done(u);
+
+ /* Free data and next 'smaller' objects */
+ if (u->meta.job)
+ job_free(u->meta.job);
+
+ for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+ bidi_set_free(u, u->meta.dependencies[d]);
+
+ free(u->meta.description);
+
+ while ((t = set_steal_first(u->meta.names)))
+ free(t);
+ set_free(u->meta.names);
+
+ free(u);
+}
+
+UnitActiveState unit_active_state(Unit *u) {
+ assert(u);
+
+ if (u->meta.load_state != UNIT_LOADED)
+ return UNIT_INACTIVE;
+
+ return UNIT_VTABLE(u)->active_state(u);
+}
+
+static int ensure_merge(Set **s, Set *other) {
+
+ if (!other)
+ return 0;
+
+ if (*s)
+ return set_merge(*s, other);
+
+ if (!(*s = set_copy(other)))
+ return -ENOMEM;
+
+ return 0;
+}
+
+/* FIXME: Does not rollback on failure! */
+int unit_merge(Unit *u, Unit *other) {
+ int r;
+ UnitDependency d;
+
+ assert(u);
+ assert(other);
+ assert(u->meta.manager == other->meta.manager);
+
+ /* This merges 'other' into 'unit'. FIXME: This does not
+ * rollback on failure. */
+
+ if (u->meta.type != u->meta.type)
+ return -EINVAL;
+
+ if (u->meta.load_state != UNIT_STUB)
+ return -EINVAL;
+
+ /* Merge names */
+ if ((r = ensure_merge(&u->meta.names, other->meta.names)) < 0)
+ return r;
+
+ /* Merge dependencies */
+ for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
+ /* fixme, the inverse mapping is missing */
+ if ((r = ensure_merge(&u->meta.dependencies[d], other->meta.dependencies[d])) < 0)
+ return r;
+
+ return 0;
+}
+
+const char* unit_id(Unit *u) {
+ assert(u);
+
+ if (u->meta.id)
+ return u->meta.id;
+
+ return set_first(u->meta.names);
+}
+
+const char *unit_description(Unit *u) {
+ assert(u);
+
+ if (u->meta.description)
+ return u->meta.description;
+
+ return unit_id(u);
+}
+
+void unit_dump(Unit *u, FILE *f, const char *prefix) {
+
+ static const char* const load_state_table[_UNIT_LOAD_STATE_MAX] = {
+ [UNIT_STUB] = "stub",
+ [UNIT_LOADED] = "loaded",
+ [UNIT_FAILED] = "failed"
+ };
+
+ static const char* const active_state_table[_UNIT_ACTIVE_STATE_MAX] = {
+ [UNIT_ACTIVE] = "active",
+ [UNIT_INACTIVE] = "inactive",
+ [UNIT_ACTIVATING] = "activating",
+ [UNIT_DEACTIVATING] = "deactivating"
+ };
+
+ static const char* const dependency_table[_UNIT_DEPENDENCY_MAX] = {
+ [UNIT_REQUIRES] = "Requires",
+ [UNIT_SOFT_REQUIRES] = "SoftRequires",
+ [UNIT_WANTS] = "Wants",
+ [UNIT_REQUISITE] = "Requisite",
+ [UNIT_SOFT_REQUISITE] = "SoftRequisite",
+ [UNIT_REQUIRED_BY] = "RequiredBy",
+ [UNIT_SOFT_REQUIRED_BY] = "SoftRequiredBy",
+ [UNIT_WANTED_BY] = "WantedBy",
+ [UNIT_CONFLICTS] = "Conflicts",
+ [UNIT_BEFORE] = "Before",
+ [UNIT_AFTER] = "After",
+ };
+
+ char *t;
+ UnitDependency d;
+ Iterator i;
+ char *prefix2;
+
+ assert(u);
+
+ if (!prefix)
+ prefix = "";
+ prefix2 = strappend(prefix, "\t");
+ if (!prefix2)
+ prefix2 = "";
+
+ fprintf(f,
+ "%s→ Unit %s:\n"
+ "%s\tDescription: %s\n"
+ "%s\tUnit Load State: %s\n"
+ "%s\tUnit Active State: %s\n",
+ prefix, unit_id(u),
+ prefix, unit_description(u),
+ prefix, load_state_table[u->meta.load_state],
+ prefix, active_state_table[unit_active_state(u)]);
+
+ SET_FOREACH(t, u->meta.names, i)
+ fprintf(f, "%s\tName: %s\n", prefix, t);
+
+ for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
+ Unit *other;
+
+ if (set_isempty(u->meta.dependencies[d]))
+ continue;
+
+ SET_FOREACH(other, u->meta.dependencies[d], i)
+ fprintf(f, "%s\t%s: %s\n", prefix, dependency_table[d], unit_id(other));
+ }
+
+ if (UNIT_VTABLE(u)->dump)
+ UNIT_VTABLE(u)->dump(u, f, prefix2);
+
+ if (u->meta.job)
+ job_dump(u->meta.job, f, prefix2);
+
+ free(prefix2);
+}
+
+/* Common implementation for multiple backends */
+int unit_load_fragment_and_dropin(Unit *u) {
+ int r;
+
+ assert(u);
+
+ /* Load a .socket file */
+ if ((r = unit_load_fragment(u)) < 0)
+ return r;
+
+ /* Load drop-in directory data */
+ if ((r = unit_load_dropin(u)) < 0)
+ return r;
+
+ return 0;
+}
+
+int unit_load(Unit *u) {
+ int r;
+
+ assert(u);
+
+ if (u->meta.in_load_queue) {
+ LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
+ u->meta.in_load_queue = false;
+ }
+
+ if (u->meta.load_state != UNIT_STUB)
+ return 0;
+
+ if (UNIT_VTABLE(u)->init)
+ if ((r = UNIT_VTABLE(u)->init(u)) < 0)
+ goto fail;
+
+ u->meta.load_state = UNIT_LOADED;
+ return 0;
+
+fail:
+ u->meta.load_state = UNIT_FAILED;
+ return r;
+}
+
+/* Errors:
+ * -EBADR: This unit type does not support starting.
+ * -EALREADY: Unit is already started.
+ * -EAGAIN: An operation is already in progress. Retry later.
+ */
+int unit_start(Unit *u) {
+ UnitActiveState state;
+
+ assert(u);
+
+ if (!UNIT_VTABLE(u)->start)
+ return -EBADR;
+
+ state = unit_active_state(u);
+ if (UNIT_IS_ACTIVE_OR_RELOADING(state))
+ return -EALREADY;
+
+ /* 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. */
+
+ return UNIT_VTABLE(u)->start(u);
+}
+
+bool unit_can_start(Unit *u) {
+ assert(u);
+
+ return !!UNIT_VTABLE(u)->start;
+}
+
+/* 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;
+
+ assert(u);
+
+ if (!UNIT_VTABLE(u)->stop)
+ return -EBADR;
+
+ state = unit_active_state(u);
+ if (state == UNIT_INACTIVE)
+ return -EALREADY;
+
+ if (state == UNIT_DEACTIVATING)
+ return 0;
+
+ return UNIT_VTABLE(u)->stop(u);
+}
+
+/* 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;
+
+ assert(u);
+
+ if (!unit_can_reload(u))
+ return -EBADR;
+
+ state = unit_active_state(u);
+ if (unit_active_state(u) == UNIT_ACTIVE_RELOADING)
+ return -EALREADY;
+
+ if (unit_active_state(u) != UNIT_ACTIVE)
+ return -ENOEXEC;
+
+ return UNIT_VTABLE(u)->reload(u);
+}
+
+bool unit_can_reload(Unit *u) {
+ assert(u);
+
+ if (!UNIT_VTABLE(u)->reload)
+ return false;
+
+ if (!UNIT_VTABLE(u)->can_reload)
+ return true;
+
+ return UNIT_VTABLE(u)->can_reload(u);
+}
+
+static void retroactively_start_dependencies(Unit *u) {
+ Iterator i;
+ Unit *other;
+
+ assert(u);
+ assert(UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u)));
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRES], i)
+ if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_SOFT_REQUIRES], i)
+ if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_REQUISITE], i)
+ if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_WANTS], i)
+ if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
+ if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
+}
+
+static void retroactively_stop_dependencies(Unit *u) {
+ Iterator i;
+ Unit *other;
+
+ assert(u);
+ assert(UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(u)));
+
+ SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
+ if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
+ manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
+}
+
+void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns) {
+ assert(u);
+ assert(os < _UNIT_ACTIVE_STATE_MAX);
+ assert(ns < _UNIT_ACTIVE_STATE_MAX);
+ assert(!(os == UNIT_ACTIVE && ns == UNIT_ACTIVATING));
+ assert(!(os == UNIT_INACTIVE && ns == UNIT_DEACTIVATING));
+
+ if (os == ns)
+ return;
+
+ if (!UNIT_IS_ACTIVE_OR_RELOADING(os) && UNIT_IS_ACTIVE_OR_RELOADING(ns))
+ u->meta.active_enter_timestamp = now(CLOCK_REALTIME);
+ else if (UNIT_IS_ACTIVE_OR_RELOADING(os) && !UNIT_IS_ACTIVE_OR_RELOADING(ns))
+ u->meta.active_exit_timestamp = now(CLOCK_REALTIME);
+
+ if (u->meta.job) {
+
+ if (u->meta.job->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_schedule_run(u->meta.job);
+
+ else {
+ assert(u->meta.job->state == JOB_RUNNING);
+
+ /* Let's check of this state change
+ * constitutes a finished job, or maybe
+ * cotradicts a running job and hence needs to
+ * invalidate jobs. */
+
+ switch (u->meta.job->type) {
+
+ case JOB_START:
+ case JOB_VERIFY_ACTIVE:
+
+ if (UNIT_IS_ACTIVE_OR_RELOADING(ns)) {
+ job_finish_and_invalidate(u->meta.job, true);
+ return;
+ } else if (ns == UNIT_ACTIVATING)
+ return;
+ else
+ job_finish_and_invalidate(u->meta.job, false);
+
+ break;
+
+ case JOB_RELOAD:
+ case JOB_RELOAD_OR_START:
+
+ if (ns == UNIT_ACTIVE) {
+ job_finish_and_invalidate(u->meta.job, true);
+ return;
+ } else if (ns == UNIT_ACTIVATING || ns == UNIT_ACTIVE_RELOADING)
+ return;
+ else
+ job_finish_and_invalidate(u->meta.job, false);
+
+ break;
+
+ case JOB_STOP:
+ case JOB_RESTART:
+ case JOB_TRY_RESTART:
+
+ if (ns == UNIT_INACTIVE) {
+ job_finish_and_invalidate(u->meta.job, true);
+ return;
+ } else if (ns == UNIT_DEACTIVATING)
+ return;
+ else
+ job_finish_and_invalidate(u->meta.job, false);
+
+ break;
+
+ default:
+ assert_not_reached("Job type unknown");
+ }
+ }
+ }
+
+ /* If this state change happened without being requested by a
+ * job, then let's retroactively start or stop dependencies */
+
+ if (UNIT_IS_INACTIVE_OR_DEACTIVATING(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);
+}
+
+int unit_watch_fd(Unit *u, int fd, uint32_t events) {
+ struct epoll_event ev;
+
+ assert(u);
+ assert(fd >= 0);
+
+ zero(ev);
+ ev.data.fd = fd;
+ ev.data.ptr = u;
+ ev.data.u32 = MANAGER_FD;
+ ev.events = events;
+
+ if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) >= 0)
+ return 0;
+
+ if (errno == EEXIST)
+ if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_MOD, fd, &ev) >= 0)
+ return 0;
+
+ return -errno;
+}
+
+void unit_unwatch_fd(Unit *u, int fd) {
+ assert(u);
+ assert(fd >= 0);
+
+ assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, fd, NULL) >= 0 || errno == ENOENT);
+}
+
+int unit_watch_pid(Unit *u, pid_t pid) {
+ assert(u);
+ assert(pid >= 1);
+
+ return hashmap_put(u->meta.manager->watch_pids, UINT32_TO_PTR(pid), u);
+}
+
+void unit_unwatch_pid(Unit *u, pid_t pid) {
+ assert(u);
+ assert(pid >= 1);
+
+ hashmap_remove(u->meta.manager->watch_pids, UINT32_TO_PTR(pid));
+}
+
+int unit_watch_timer(Unit *u, usec_t delay, int *id) {
+ struct epoll_event ev;
+ int fd;
+ struct itimerspec its;
+ int flags;
+ bool ours;
+
+ assert(u);
+ assert(id);
+
+ /* This will try to reuse the old timer if there is one */
+
+ if (*id >= 0) {
+ ours = false;
+ fd = *id;
+
+ } else {
+ ours = true;
+
+ if ((fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) < 0)
+ return -errno;
+ }
+
+ zero(its);
+
+ if (delay <= 0) {
+ /* Set absolute time in the past, but not 0, since we
+ * don't want to disarm the timer */
+ its.it_value.tv_sec = 0;
+ its.it_value.tv_nsec = 1;
+
+ flags = TFD_TIMER_ABSTIME;
+ } else {
+ timespec_store(&its.it_value, delay);
+ flags = 0;
+ }
+
+ /* This will also flush the elapse counter */
+ if (timerfd_settime(fd, flags, &its, NULL) < 0)
+ goto fail;
+
+ zero(ev);
+ ev.data.fd = fd;
+ ev.data.ptr = u;
+ ev.data.u32 = MANAGER_TIMER;
+ ev.events = POLLIN;
+
+ if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
+ goto fail;
+
+ *id = fd;
+ return 0;
+
+fail:
+ if (ours)
+ assert_se(close_nointr(fd) == 0);
+
+ return -errno;
+}
+
+void unit_unwatch_timer(Unit *u, int *id) {
+ assert(u);
+ assert(id);
+
+ if (*id < 0)
+ return;
+
+ assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, *id, NULL) >= 0);
+ assert_se(close_nointr(*id) == 0);
+ *id = -1;
+}
+
+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:
+ return true;
+
+ case JOB_STOP:
+ case JOB_RESTART:
+ case JOB_TRY_RESTART:
+ return unit_can_start(u);
+
+ case JOB_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");
+ }
+}
+
+int unit_add_dependency(Unit *u, UnitDependency d, Unit *other) {
+
+ static const UnitDependency inverse_table[_UNIT_DEPENDENCY_MAX] = {
+ [UNIT_REQUIRES] = UNIT_REQUIRED_BY,
+ [UNIT_SOFT_REQUIRES] = UNIT_SOFT_REQUIRED_BY,
+ [UNIT_WANTS] = UNIT_WANTED_BY,
+ [UNIT_REQUISITE] = UNIT_REQUIRED_BY,
+ [UNIT_SOFT_REQUISITE] = UNIT_SOFT_REQUIRED_BY,
+ [UNIT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
+ [UNIT_SOFT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
+ [UNIT_WANTED_BY] = _UNIT_DEPENDENCY_INVALID,
+ [UNIT_CONFLICTS] = UNIT_CONFLICTS,
+ [UNIT_BEFORE] = UNIT_AFTER,
+ [UNIT_AFTER] = UNIT_BEFORE
+ };
+ int r;
+
+ assert(u);
+ assert(d >= 0 && d < _UNIT_DEPENDENCY_MAX);
+ assert(inverse_table[d] != _UNIT_DEPENDENCY_INVALID);
+ assert(other);
+
+ /* We won't allow dependencies on ourselves. We will not
+ * consider them an error however. */
+ if (u == other)
+ return 0;
+
+ if ((r = set_ensure_allocated(&u->meta.dependencies[d], trivial_hash_func, trivial_compare_func)) < 0)
+ return r;
+
+ if ((r = set_ensure_allocated(&other->meta.dependencies[inverse_table[d]], trivial_hash_func, trivial_compare_func)) < 0)
+ return r;
+
+ if ((r = set_put(u->meta.dependencies[d], other)) < 0)
+ return r;
+
+ if ((r = set_put(other->meta.dependencies[inverse_table[d]], u)) < 0) {
+ set_remove(u->meta.dependencies[d], other);
+ return r;
+ }
+
+ return 0;
+}