core: general cgroup rework

Replace the very generic cgroup hookup with a much simpler one. With
this change only the high-level cgroup settings remain, the ability to
set arbitrary cgroup attributes is removed, so is support for adding
units to arbitrary cgroup controllers or setting arbitrary paths for
them (especially paths that are different for the various controllers).

This also introduces a new -.slice root slice, that is the parent of
system.slice and friends. This enables easy admin configuration of
root-level cgrouo properties.

This replaces DeviceDeny= by DevicePolicy=, and implicitly adds in
/dev/null, /dev/zero and friends if DeviceAllow= is used (unless this is
turned off by DevicePolicy=).

1 files changed, 49 insertions, 30 deletions

diff --git a/src/core/slice.c b/src/core/slice.c
index c1c33fe5c..df2d91e47 100644
--- a/src/core/slice.c
+++ b/src/core/slice.c
@@ -36,6 +36,23 @@ static const UnitActiveState state_translation_table[_SLICE_STATE_MAX] = {
         [SLICE_ACTIVE] = UNIT_ACTIVE
 };
 
+static void slice_init(Unit *u) {
+        Slice *s = SLICE(u);
+
+        assert(u);
+        assert(u->load_state == UNIT_STUB);
+
+        cgroup_context_init(&s->cgroup_context);
+}
+
+static void slice_done(Unit *u) {
+        Slice *s = SLICE(u);
+
+        assert(u);
+
+        cgroup_context_done(&s->cgroup_context);
+}
+
 static void slice_set_state(Slice *t, SliceState state) {
         SliceState old_state;
         assert(t);
@@ -52,23 +69,25 @@ static void slice_set_state(Slice *t, SliceState state) {
         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], true);
 }
 
-static int slice_add_slice_link(Slice *s) {
+static int slice_add_parent_slice(Slice *s) {
         char *a, *dash;
-        int r;
         Unit *parent;
+        int r;
 
         assert(s);
 
-        if (UNIT_DEREF(UNIT(s)->slice))
+        if (UNIT_ISSET(UNIT(s)->slice))
                 return 0;
 
-        a = strdupa(UNIT(s)->id);
-
-        dash = strrchr(a, '-');
-        if (!dash)
+        if (unit_has_name(UNIT(s), SPECIAL_ROOT_SLICE))
                 return 0;
 
-        strcpy(dash, ".slice");
+        a = strdupa(UNIT(s)->id);
+        dash = strrchr(a, '-');
+        if (dash)
+                strcpy(dash, ".slice");
+        else
+                a = (char*) SPECIAL_ROOT_SLICE;
 
         r = manager_load_unit(UNIT(s)->manager, a, NULL, NULL, &parent);
         if (r < 0)
@@ -102,14 +121,15 @@ static int slice_verify(Slice *s) {
 
                 a = strdupa(UNIT(s)->id);
                 dash = strrchr(a, '-');
-                if (dash) {
+                if (dash)
                         strcpy(dash, ".slice");
+                else
+                        a = (char*) SPECIAL_ROOT_SLICE;
 
-                        if (!unit_has_name(UNIT_DEREF(UNIT(s)->slice), a)) {
-                                log_error_unit(UNIT(s)->id,
-                                               "%s located outside its parent slice. Refusing.", UNIT(s)->id);
-                                return -EINVAL;
-                        }
+                if (!unit_has_name(UNIT_DEREF(UNIT(s)->slice), a)) {
+                        log_error_unit(UNIT(s)->id,
+                                       "%s located outside its parent slice. Refusing.", UNIT(s)->id);
+                        return -EINVAL;
                 }
         }
 
@@ -122,14 +142,14 @@ static int slice_load(Unit *u) {
 
         assert(s);
 
-        r = unit_load_fragment_and_dropin(u);
+        r = unit_load_fragment_and_dropin_optional(u);
         if (r < 0)
                 return r;
 
         /* This is a new unit? Then let's add in some extras */
         if (u->load_state == UNIT_LOADED) {
 
-                r = slice_add_slice_link(s);
+                r = slice_add_parent_slice(s);
                 if (r < 0)
                         return r;
 
@@ -138,10 +158,6 @@ static int slice_load(Unit *u) {
                         if (r < 0)
                                 return r;
                 }
-
-                r = unit_add_default_cgroups(UNIT(s));
-                if (r < 0)
-                        return r;
         }
 
         return slice_verify(s);
@@ -168,20 +184,17 @@ static void slice_dump(Unit *u, FILE *f, const char *prefix) {
         fprintf(f,
                 "%sSlice State: %s\n",
                 prefix, slice_state_to_string(t->state));
+
+        cgroup_context_dump(&t->cgroup_context, f, prefix);
 }
 
 static int slice_start(Unit *u) {
         Slice *t = SLICE(u);
-        int r;
 
         assert(t);
         assert(t->state == SLICE_DEAD);
 
-        r = cgroup_bonding_realize_list(u->cgroup_bondings);
-        if (r < 0)
-                return r;
-
-        cgroup_attribute_apply_list(u->cgroup_attributes, u->cgroup_bondings);
+        unit_realize_cgroup(u);
 
         slice_set_state(t, SLICE_ACTIVE);
         return 0;
@@ -193,8 +206,8 @@ static int slice_stop(Unit *u) {
         assert(t);
         assert(t->state == SLICE_ACTIVE);
 
-        /* We do not need to trim the cgroup explicitly, unit_notify()
-         * will do that for us anyway. */
+        /* We do not need to destroy the cgroup explicitly,
+         * unit_notify() will do that for us anyway. */
 
         slice_set_state(t, SLICE_DEAD);
         return 0;
@@ -264,10 +277,16 @@ const UnitVTable slice_vtable = {
                 "Slice\0"
                 "Install\0",
 
+        .private_section = "Slice",
+        .cgroup_context_offset = offsetof(Slice, cgroup_context),
+
         .no_alias = true,
         .no_instances = true,
 
+        .init = slice_init,
         .load = slice_load,
+        .done = slice_done,
+
         .coldplug = slice_coldplug,
 
         .dump = slice_dump,
@@ -288,11 +307,11 @@ const UnitVTable slice_vtable = {
 
         .status_message_formats = {
                 .finished_start_job = {
-                        [JOB_DONE]       = "Installed slice %s.",
+                        [JOB_DONE]       = "Created slice %s.",
                         [JOB_DEPENDENCY] = "Dependency failed for %s.",
                 },
                 .finished_stop_job = {
-                        [JOB_DONE]       = "Deinstalled slice %s.",
+                        [JOB_DONE]       = "Removed slice %s.",
                 },
         },
 };