unit: rework resource management API

This introduces a new static list of known attributes and their special
semantics. This means that cgroup attribute values can now be
automatically translated from user to kernel notation for command line
set settings, too.

This also adds proper support for multi-line attributes.

1 files changed, 195 insertions, 134 deletions

diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index 4f968c20f2..7c23e1e616 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -344,8 +344,8 @@ static int bus_unit_append_cgroup_attrs(DBusMessageIter *i, const char *property
                 char _cleanup_free_ *v = NULL;
                 bool success;
 
-                if (a->map_callback)
-                        a->map_callback(a->controller, a->name, a->value, &v);
+                if (a->semantics && a->semantics->map_write)
+                        a->semantics->map_write(a->semantics, a->value, &v);
 
                 success =
                         dbus_message_iter_open_container(&sub, DBUS_TYPE_STRUCT, NULL, &sub2) &&
@@ -472,7 +472,7 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 if (!reply)
                         goto oom;
 
-        } else if (streq_ptr(dbus_message_get_member(message), "SetControlGroups")) {
+        } else if (streq_ptr(dbus_message_get_member(message), "SetControlGroup")) {
                 DBusMessageIter iter;
 
                 SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "start");
@@ -488,7 +488,7 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 if (!reply)
                         goto oom;
 
-        } else if (streq_ptr(dbus_message_get_member(message), "UnsetControlGroups")) {
+        } else if (streq_ptr(dbus_message_get_member(message), "UnsetControlGroup")) {
                 DBusMessageIter iter;
 
                 SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "stop");
@@ -496,14 +496,14 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 if (!dbus_message_iter_init(message, &iter))
                         goto oom;
 
-                r = bus_unit_cgroup_set(u, &iter);
+                r = bus_unit_cgroup_unset(u, &iter);
                 if (r < 0)
                         return bus_send_error_reply(connection, message, NULL, r);
 
                 reply = dbus_message_new_method_return(message);
                 if (!reply)
                         goto oom;
-        } else if (streq_ptr(dbus_message_get_member(message), "GetControlGroupAttributes")) {
+        } else if (streq_ptr(dbus_message_get_member(message), "GetControlGroupAttribute")) {
                 DBusMessageIter iter;
                 _cleanup_strv_free_ char **list = NULL;
 
@@ -524,7 +524,7 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 if (bus_append_strv_iter(&iter, list) < 0)
                         goto oom;
 
-        } else if (streq_ptr(dbus_message_get_member(message), "SetControlGroupAttributes")) {
+        } else if (streq_ptr(dbus_message_get_member(message), "SetControlGroupAttribute")) {
                 DBusMessageIter iter;
 
                 SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "start");
@@ -540,7 +540,7 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 if (!reply)
                         goto oom;
 
-        } else if (streq_ptr(dbus_message_get_member(message), "UnsetControlGroupAttributes")) {
+        } else if (streq_ptr(dbus_message_get_member(message), "UnsetControlGroupAttribute")) {
                 DBusMessageIter iter;
 
                 SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "stop");
@@ -897,17 +897,17 @@ oom:
         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 }
 
-static int next_and_parse_mode(DBusMessageIter *iter, bool *runtime) {
+static int parse_mode(DBusMessageIter *iter, bool *runtime, bool next) {
         const char *mode;
+        int r;
 
         assert(iter);
         assert(runtime);
 
-        dbus_message_iter_next(iter);
-        if (dbus_message_iter_get_arg_type(iter) != DBUS_TYPE_STRING)
-                return -EINVAL;
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &mode, next);
+        if (r < 0)
+                return r;
 
-        dbus_message_iter_get_basic(iter, &mode);
         if (streq(mode, "runtime"))
                 *runtime = true;
         else if (streq(mode, "persistent"))
@@ -919,10 +919,11 @@ static int next_and_parse_mode(DBusMessageIter *iter, bool *runtime) {
 }
 
 int bus_unit_cgroup_set(Unit *u, DBusMessageIter *iter) {
-        int r;
-        _cleanup_strv_free_ char **a = NULL;
-        char **name;
+        _cleanup_free_ char *controller = NULL, *old_path = NULL, *new_path = NULL, *contents = NULL;
+        const char *name;
+        CGroupBonding *b;
         bool runtime;
+        int r;
 
         assert(u);
         assert(iter);
@@ -930,60 +931,74 @@ int bus_unit_cgroup_set(Unit *u, DBusMessageIter *iter) {
         if (!unit_get_exec_context(u))
                 return -EINVAL;
 
-        r = bus_parse_strv_iter(iter, &a);
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &name, true);
         if (r < 0)
                 return r;
 
-        r = next_and_parse_mode(iter, &runtime);
+        r = parse_mode(iter, &runtime, false);
         if (r < 0)
                 return r;
 
-        STRV_FOREACH(name, a) {
-                _cleanup_free_ char *controller = NULL, *old_path = NULL, *new_path = NULL, *contents = NULL;
-                CGroupBonding *b;
-
-                r = cg_split_spec(*name, &controller, &new_path);
-                if (r < 0)
-                        return r;
+        r = cg_split_spec(name, &controller, &new_path);
+        if (r < 0)
+                return r;
 
-                b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
-                if (b) {
-                        old_path = strdup(b->path);
-                        if (!old_path)
-                                return -ENOMEM;
-                }
+        if (!new_path) {
+                new_path = unit_default_cgroup_path(u);
+                if (!new_path)
+                        return -ENOMEM;
+        }
 
-                r = unit_add_cgroup_from_text(u, *name, true, &b);
-                if (r < 0)
-                        return r;
+        if (!controller || streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+                return -EINVAL;
 
-                if (r > 0) {
-                        /* Try to move things to the new place, and clean up the old place */
-                        cgroup_bonding_realize(b);
-                        cgroup_bonding_migrate(b, u->cgroup_bondings);
+        b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
+        if (b) {
+                if (streq(b->path, new_path))
+                        return 0;
 
-                        if (old_path)
-                                cg_trim(controller, old_path, true);
-                }
+                if (b->essential)
+                        return -EINVAL;
 
-                contents = strjoin("[", UNIT_VTABLE(u)->exec_section, "]\n"
-                                   "ControlGroup=", *name, "\n", NULL);
-                if (!contents)
+                old_path = strdup(b->path);
+                if (!old_path)
                         return -ENOMEM;
+        }
 
-                r = unit_write_drop_in(u, runtime, *name, contents);
-                if (r < 0)
-                        return r;
+        r = unit_add_cgroup_from_text(u, name, true, &b);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                CGroupAttribute *a;
+
+                /* Try to move things to the new place, and clean up the old place */
+                cgroup_bonding_realize(b);
+                cgroup_bonding_migrate(b, u->cgroup_bondings);
+
+                if (old_path)
+                        cg_trim(controller, old_path, true);
+
+                /* Apply the attributes to the new group */
+                LIST_FOREACH(by_unit, a, u->cgroup_attributes)
+                        if (streq(a->controller, controller))
+                                cgroup_attribute_apply(a, b);
         }
 
-        return 0;
+        contents = strjoin("[", UNIT_VTABLE(u)->exec_section, "]\n"
+                           "ControlGroup=", name, "\n", NULL);
+        if (!contents)
+                return -ENOMEM;
+
+        return unit_write_drop_in(u, runtime, controller, contents);
 }
 
 int bus_unit_cgroup_unset(Unit *u, DBusMessageIter *iter) {
-        _cleanup_strv_free_ char **a = NULL;
-        char **name;
-        int r;
+        _cleanup_free_ char *controller = NULL, *path = NULL, *target = NULL;
+        const char *name;
+        CGroupAttribute *a, *n;
+        CGroupBonding *b;
         bool runtime;
+        int r;
 
         assert(u);
         assert(iter);
@@ -991,50 +1006,57 @@ int bus_unit_cgroup_unset(Unit *u, DBusMessageIter *iter) {
         if (!unit_get_exec_context(u))
                 return -EINVAL;
 
-        r = bus_parse_strv_iter(iter, &a);
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &name, true);
         if (r < 0)
                 return r;
 
-        r = next_and_parse_mode(iter, &runtime);
+        r = parse_mode(iter, &runtime, false);
         if (r < 0)
                 return r;
 
-        STRV_FOREACH(name, a) {
-                _cleanup_free_ char *controller = NULL, *path = NULL, *target = NULL;
-                CGroupBonding *b;
+        r = cg_split_spec(name, &controller, &path);
+        if (r < 0)
+                return r;
 
-                r = cg_split_spec(*name, &controller, &path);
-                if (r < 0)
-                        return r;
+        if (!controller || streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+                return -EINVAL;
 
-                if (!controller || streq(controller, SYSTEMD_CGROUP_CONTROLLER))
-                        return -EINVAL;
+        b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
+        if (!b)
+                return -ENOENT;
 
-                unit_remove_drop_in(u, runtime, *name);
+        if (path && !path_equal(path, b->path))
+                return -ENOENT;
 
-                b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
-                if (!b)
-                        continue;
+        if (b->essential)
+                return -EINVAL;
 
-                if (path && !path_equal(path, b->path))
-                        continue;
+        unit_remove_drop_in(u, runtime, controller);
 
-                if (b->essential)
-                        return -EINVAL;
+        /* Try to migrate the old group away */
+        if (cg_get_by_pid(controller, 0, &target) >= 0)
+                cgroup_bonding_migrate_to(u->cgroup_bondings, target, false);
+
+        cgroup_bonding_free(b, true);
 
-                /* Try to migrate the old group away */
-                if (cg_get_by_pid(controller, 0, &target) >= 0)
-                        cgroup_bonding_migrate_to(u->cgroup_bondings, target, false);
+        /* Drop all attributes of this controller */
+        LIST_FOREACH_SAFE(by_unit, a, n, u->cgroup_attributes) {
+                if (!streq(a->controller, controller))
+                        continue;
 
-                cgroup_bonding_free(b, true);
+                unit_remove_drop_in(u, runtime, a->name);
+                cgroup_attribute_free(a);
         }
 
         return 0;
 }
 
 int bus_unit_cgroup_attribute_get(Unit *u, DBusMessageIter *iter, char ***_result) {
-        _cleanup_strv_free_ char **l = NULL, **result = NULL;
-        char **name;
+        _cleanup_free_ char *controller = NULL;
+        CGroupAttribute *a;
+        CGroupBonding *b;
+        const char *name;
+        char **l = NULL;
         int r;
 
         assert(u);
@@ -1044,63 +1066,99 @@ int bus_unit_cgroup_attribute_get(Unit *u, DBusMessageIter *iter, char ***_resul
         if (!unit_get_exec_context(u))
                 return -EINVAL;
 
-        r = bus_parse_strv_iter(iter, &l);
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &name, false);
         if (r < 0)
                 return r;
 
-        STRV_FOREACH(name, l) {
-                _cleanup_free_ char *controller = NULL;
-                CGroupAttribute *a;
-                CGroupBonding *b;
+        r = cg_controller_from_attr(name, &controller);
+        if (r < 0)
+                return r;
+
+        /* First attempt, read the value from the kernel */
+        b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
+        if (b) {
+                _cleanup_free_ char *p = NULL, *v = NULL;
 
-                r = cg_controller_from_attr(*name, &controller);
+                r = cg_get_path(b->controller, b->path, name, &p);
                 if (r < 0)
                         return r;
 
-                /* First attempt, read the value from the kernel */
-                b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
-                if (b) {
-                        _cleanup_free_ char *p = NULL, *v = NULL;
+                r = read_full_file(p, &v, NULL);
+                if (r >= 0) {
+                        /* Split on new lines */
+                        l = strv_split_newlines(v);
+                        if (!l)
+                                return -ENOMEM;
 
-                        r = cg_get_path(b->controller, b->path, *name, &p);
-                        if (r < 0)
-                                return r;
+                        *_result = l;
+                        return 0;
 
-                        r = read_full_file(p, &v, NULL);
-                        if (r >= 0) {
-                                r = strv_extend(&result, v);
-                                if (r < 0)
-                                        return r;
-
-                                continue;
-                        } else if (r != -ENOENT)
-                                return r;
                 }
+        }
 
-                /* If that didn't work, read our cached value */
-                a = cgroup_attribute_find_list(u->cgroup_attributes, NULL, *name);
-                if (a) {
-                        r = strv_extend(&result, a->value);
-                        if (r < 0)
-                                return r;
+        /* If that didn't work, read our cached value */
+        LIST_FOREACH(by_unit, a, u->cgroup_attributes) {
 
+                if (!cgroup_attribute_matches(a, controller, name))
                         continue;
-                }
 
-                return -ENOENT;
+                r = strv_extend(&l, a->value);
+                if (r < 0) {
+                        strv_free(l);
+                        return r;
+                }
         }
 
-        *_result = result;
-        result = NULL;
+        if (!l)
+                return -ENOENT;
 
+        *_result = l;
         return 0;
 }
 
+static int update_attribute_drop_in(Unit *u, bool runtime, const char *name) {
+        _cleanup_free_ char *buf = NULL;
+        CGroupAttribute *a;
+
+        assert(u);
+        assert(name);
+
+        LIST_FOREACH(by_unit, a, u->cgroup_attributes) {
+                if (!cgroup_attribute_matches(a, NULL, name))
+                        continue;
+
+                if (!buf) {
+                        buf = strjoin("[", UNIT_VTABLE(u)->exec_section, "]\n"
+                                      "ControlGroupAttribute=", a->name, " ", a->value, "\n", NULL);
+
+                        if (!buf)
+                                return -ENOMEM;
+                } else {
+                        char *b;
+
+                        b = strjoin(buf,
+                                    "ControlGroupAttribute=", a->name, " ", a->value, "\n", NULL);
+
+                        if (!b)
+                                return -ENOMEM;
+
+                        free(buf);
+                        buf = b;
+                }
+        }
+
+        if (buf)
+                return unit_write_drop_in(u, runtime, name, buf);
+        else
+                return unit_remove_drop_in(u, runtime, name);
+}
+
 int bus_unit_cgroup_attribute_set(Unit *u, DBusMessageIter *iter) {
         _cleanup_strv_free_ char **l = NULL;
         int r;
         bool runtime = false;
-        char **name, **value;
+        char **value;
+        const char *name;
 
         assert(u);
         assert(iter);
@@ -1108,19 +1166,34 @@ int bus_unit_cgroup_attribute_set(Unit *u, DBusMessageIter *iter) {
         if (!unit_get_exec_context(u))
                 return -EINVAL;
 
-        r = bus_parse_strv_pairs_iter(iter, &l);
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &name, true);
+        if (r < 0)
+                return r;
+
+        r = bus_parse_strv_iter(iter, &l);
         if (r < 0)
                 return r;
 
-        r = next_and_parse_mode(iter, &runtime);
+        if (!dbus_message_iter_next(iter))
+                return -EINVAL;
+
+        r = parse_mode(iter, &runtime, false);
         if (r < 0)
                 return r;
 
-        STRV_FOREACH_PAIR(name, value, l) {
-                _cleanup_free_ char *contents = NULL;
+        STRV_FOREACH(value, l) {
+                _cleanup_free_ char *v = NULL;
                 CGroupAttribute *a;
+                const CGroupSemantics *s;
+
+                r = cgroup_semantics_find(NULL, name, *value, &v, &s);
+                if (r < 0)
+                        return r;
+
+                if (s && !s->multiple && l[1])
+                        return -EINVAL;
 
-                r = unit_add_cgroup_attribute(u, NULL, *name, *value, NULL, &a);
+                r = unit_add_cgroup_attribute(u, s, NULL, name, v ? v : *value, &a);
                 if (r < 0)
                         return r;
 
@@ -1144,22 +1217,17 @@ int bus_unit_cgroup_attribute_set(Unit *u, DBusMessageIter *iter) {
                         cgroup_attribute_apply(a, u->cgroup_bondings);
                 }
 
-                contents = strjoin("[", UNIT_VTABLE(u)->exec_section, "]\n"
-                                   "ControlGroupAttribute=", *name, " ", *value, "\n", NULL);
-                if (!contents)
-                        return -ENOMEM;
-
-                r = unit_write_drop_in(u, runtime, *name, contents);
-                if (r < 0)
-                        return r;
         }
 
+        r = update_attribute_drop_in(u, runtime, name);
+        if (r < 0)
+                return r;
+
         return 0;
 }
 
 int bus_unit_cgroup_attribute_unset(Unit *u, DBusMessageIter *iter) {
-        _cleanup_strv_free_ char **l = NULL;
-        char **name;
+        const char *name;
         bool runtime;
         int r;
 
@@ -1169,23 +1237,16 @@ int bus_unit_cgroup_attribute_unset(Unit *u, DBusMessageIter *iter) {
         if (!unit_get_exec_context(u))
                 return -EINVAL;
 
-        r = bus_parse_strv_iter(iter, &l);
+        r = bus_iter_get_basic_and_next(iter, DBUS_TYPE_STRING, &name, true);
         if (r < 0)
                 return r;
 
-        r = next_and_parse_mode(iter, &runtime);
+        r = parse_mode(iter, &runtime, false);
         if (r < 0)
                 return r;
 
-        STRV_FOREACH(name, l) {
-                CGroupAttribute *a;
-
-                a = cgroup_attribute_find_list(u->cgroup_attributes, NULL, *name);
-                if (a)
-                        cgroup_attribute_free(a);
-
-                unit_remove_drop_in(u, runtime, *name);
-        }
+        cgroup_attribute_free_some(u->cgroup_attributes, NULL, name);
+        update_attribute_drop_in(u, runtime, name);
 
         return 0;
 }