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, 46 insertions, 358 deletions

diff --git a/src/core/unit.c b/src/core/unit.c
index f75045dc4..0dcf85b5e 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -44,7 +44,6 @@
 #include "special.h"
 #include "cgroup-util.h"
 #include "missing.h"
-#include "cgroup-attr.h"
 #include "mkdir.h"
 #include "label.h"
 #include "fileio-label.h"
@@ -402,9 +401,10 @@ void unit_free(Unit *u) {
                 u->manager->n_in_gc_queue--;
         }
 
-        cgroup_bonding_free_list(u->cgroup_bondings, u->manager->n_reloading <= 0);
-        cgroup_attribute_free_list(u->cgroup_attributes);
+        if (u->in_cgroup_queue)
+                LIST_REMOVE(Unit, cgroup_queue, u->manager->cgroup_queue, u);
 
+        free(u->cgroup_path);
         free(u->description);
         strv_free(u->documentation);
         free(u->fragment_path);
@@ -673,7 +673,10 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
                 "%s\tInactive Enter Timestamp: %s\n"
                 "%s\tGC Check Good: %s\n"
                 "%s\tNeed Daemon Reload: %s\n"
-                "%s\tSlice: %s\n",
+                "%s\tSlice: %s\n"
+                "%s\tCGroup: %s\n"
+                "%s\tCGroup realized: %s\n"
+                "%s\tCGroup mask: 0x%x\n",
                 prefix, u->id,
                 prefix, unit_description(u),
                 prefix, strna(u->instance),
@@ -685,7 +688,10 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
                 prefix, strna(format_timestamp(timestamp4, sizeof(timestamp4), u->inactive_enter_timestamp.realtime)),
                 prefix, yes_no(unit_check_gc(u)),
                 prefix, yes_no(unit_need_daemon_reload(u)),
-                prefix, strna(unit_slice_name(u)));
+                prefix, strna(unit_slice_name(u)),
+                prefix, strna(u->cgroup_path),
+                prefix, yes_no(u->cgroup_realized),
+                prefix, u->cgroup_mask);
 
         SET_FOREACH(t, u->names, i)
                 fprintf(f, "%s\tName: %s\n", prefix, t);
@@ -735,8 +741,6 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
         }
 
         if (u->load_state == UNIT_LOADED) {
-                CGroupBonding *b;
-                CGroupAttribute *a;
 
                 fprintf(f,
                         "%s\tStopWhenUnneeded: %s\n"
@@ -754,20 +758,6 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
                         prefix, yes_no(u->ignore_on_isolate),
                         prefix, yes_no(u->ignore_on_snapshot));
 
-                LIST_FOREACH(by_unit, b, u->cgroup_bondings)
-                        fprintf(f, "%s\tControlGroup: %s:%s\n",
-                                prefix, b->controller, b->path);
-
-                LIST_FOREACH(by_unit, a, u->cgroup_attributes) {
-                        _cleanup_free_ char *v = NULL;
-
-                        if (a->semantics && a->semantics->map_write)
-                                a->semantics->map_write(a->semantics, a->value, &v);
-
-                        fprintf(f, "%s\tControlGroupAttribute: %s %s \"%s\"\n",
-                                prefix, a->controller, a->name, v ? v : a->value);
-                }
-
                 if (UNIT_VTABLE(u)->dump)
                         UNIT_VTABLE(u)->dump(u, f, prefix2);
 
@@ -795,14 +785,16 @@ int unit_load_fragment_and_dropin(Unit *u) {
         assert(u);
 
         /* Load a .service file */
-        if ((r = unit_load_fragment(u)) < 0)
+        r = unit_load_fragment(u);
+        if (r < 0)
                 return r;
 
         if (u->load_state == UNIT_STUB)
                 return -ENOENT;
 
         /* Load drop-in directory data */
-        if ((r = unit_load_dropin(unit_follow_merge(u))) < 0)
+        r = unit_load_dropin(unit_follow_merge(u));
+        if (r < 0)
                 return r;
 
         return 0;
@@ -818,14 +810,16 @@ int unit_load_fragment_and_dropin_optional(Unit *u) {
          * something can be loaded or not doesn't matter. */
 
         /* Load a .service file */
-        if ((r = unit_load_fragment(u)) < 0)
+        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 */
-        if ((r = unit_load_dropin(unit_follow_merge(u))) < 0)
+        r = unit_load_dropin(unit_follow_merge(u));
+        if (r < 0)
                 return r;
 
         return 0;
@@ -880,8 +874,12 @@ static int unit_add_default_dependencies(Unit *u) {
                                 return r;
                 }
 
-        if (u->default_dependencies && UNIT_ISSET(u->slice)) {
-                r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, UNIT_DEREF(u->slice), true);
+        if (u->default_dependencies && unit_get_cgroup_context(u)) {
+                if (UNIT_ISSET(u->slice))
+                        r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, UNIT_DEREF(u->slice), true);
+                else
+                        r = unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_WANTS, SPECIAL_ROOT_SLICE, NULL, true);
+
                 if (r < 0)
                         return r;
         }
@@ -1382,7 +1380,7 @@ void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, bool reload_su
         }
 
         if (UNIT_IS_INACTIVE_OR_FAILED(ns))
-                cgroup_bonding_trim_list(u->cgroup_bondings, true);
+                unit_destroy_cgroup(u);
 
         if (UNIT_IS_INACTIVE_OR_FAILED(os) != UNIT_IS_INACTIVE_OR_FAILED(ns)) {
                 ExecContext *ec = unit_get_exec_context(u);
@@ -1952,51 +1950,16 @@ char *unit_dbus_path(Unit *u) {
         return unit_dbus_path_from_name(u->id);
 }
 
-static int unit_add_cgroup(Unit *u, CGroupBonding *b) {
-        int r;
-
-        assert(u);
-        assert(b);
-
-        assert(b->path);
-
-        if (!b->controller) {
-                b->controller = strdup(SYSTEMD_CGROUP_CONTROLLER);
-                if (!b->controller)
-                        return log_oom();
-
-                b->ours = true;
-        }
-
-        /* Ensure this hasn't been added yet */
-        assert(!b->unit);
-
-        if (streq(b->controller, SYSTEMD_CGROUP_CONTROLLER)) {
-                CGroupBonding *l;
-
-                l = hashmap_get(u->manager->cgroup_bondings, b->path);
-                LIST_PREPEND(CGroupBonding, by_path, l, b);
-
-                r = hashmap_replace(u->manager->cgroup_bondings, b->path, l);
-                if (r < 0) {
-                        LIST_REMOVE(CGroupBonding, by_path, l, b);
-                        return r;
-                }
-        }
-
-        LIST_PREPEND(CGroupBonding, by_unit, u->cgroup_bondings, b);
-        b->unit = u;
-
-        return 0;
-}
-
 char *unit_default_cgroup_path(Unit *u) {
         _cleanup_free_ char *escaped_instance = NULL, *slice = NULL;
         int r;
 
         assert(u);
 
-        if (UNIT_ISSET(u->slice)) {
+        if (unit_has_name(u, SPECIAL_ROOT_SLICE))
+                return strdup(u->manager->cgroup_root);
+
+        if (UNIT_ISSET(u->slice) && !unit_has_name(UNIT_DEREF(u->slice), SPECIAL_ROOT_SLICE)) {
                 r = cg_slice_to_path(UNIT_DEREF(u->slice)->id, &slice);
                 if (r < 0)
                         return NULL;
@@ -2026,148 +1989,6 @@ char *unit_default_cgroup_path(Unit *u) {
                                escaped_instance, NULL);
 }
 
-int unit_add_cgroup_from_text(Unit *u, const char *name, bool overwrite, CGroupBonding **ret) {
-        char *controller = NULL, *path = NULL;
-        CGroupBonding *b = NULL;
-        bool ours = false;
-        int r;
-
-        assert(u);
-        assert(name);
-
-        r = cg_split_spec(name, &controller, &path);
-        if (r < 0)
-                return r;
-
-        if (!path) {
-                path = unit_default_cgroup_path(u);
-                ours = true;
-        }
-
-        if (!controller) {
-                controller = strdup("systemd");
-                ours = true;
-        }
-
-        if (!path || !controller) {
-                free(path);
-                free(controller);
-                return log_oom();
-        }
-
-        if (streq(controller, "systemd")) {
-                /* Within the systemd unit hierarchy we do not allow changes. */
-                if (path_startswith(path, "/system")) {
-                        log_warning_unit(u->id, "Manipulating the systemd:/system cgroup hierarchy is not permitted.");
-                        free(path);
-                        free(controller);
-                        return -EPERM;
-                }
-        }
-
-        b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
-        if (b) {
-                if (streq(path, b->path)) {
-                        free(path);
-                        free(controller);
-
-                        if (ret)
-                                *ret = b;
-                        return 0;
-                }
-
-                if (overwrite && !b->essential) {
-                        free(controller);
-
-                        free(b->path);
-                        b->path = path;
-
-                        b->ours = ours;
-                        b->realized = false;
-
-                        if (ret)
-                                *ret = b;
-
-                        return 1;
-                }
-
-                r = -EEXIST;
-                b = NULL;
-                goto fail;
-        }
-
-        b = new0(CGroupBonding, 1);
-        if (!b) {
-                r = -ENOMEM;
-                goto fail;
-        }
-
-        b->controller = controller;
-        b->path = path;
-        b->ours = ours;
-        b->essential = streq(controller, SYSTEMD_CGROUP_CONTROLLER);
-
-        r = unit_add_cgroup(u, b);
-        if (r < 0)
-                goto fail;
-
-        if (ret)
-                *ret = b;
-
-        return 1;
-
-fail:
-        free(path);
-        free(controller);
-        free(b);
-
-        return r;
-}
-
-static int unit_add_one_default_cgroup(Unit *u, const char *controller) {
-        CGroupBonding *b = NULL;
-        int r = -ENOMEM;
-
-        assert(u);
-
-        if (controller && !cg_controller_is_valid(controller, true))
-                return -EINVAL;
-
-        if (!controller)
-                controller = SYSTEMD_CGROUP_CONTROLLER;
-
-        if (cgroup_bonding_find_list(u->cgroup_bondings, controller))
-                return 0;
-
-        b = new0(CGroupBonding, 1);
-        if (!b)
-                return -ENOMEM;
-
-        b->controller = strdup(controller);
-        if (!b->controller)
-                goto fail;
-
-        b->path = unit_default_cgroup_path(u);
-        if (!b->path)
-                goto fail;
-
-        b->ours = true;
-        b->essential = streq(controller, SYSTEMD_CGROUP_CONTROLLER);
-
-        r = unit_add_cgroup(u, b);
-        if (r < 0)
-                goto fail;
-
-        return 1;
-
-fail:
-        free(b->path);
-        free(b->controller);
-        free(b);
-
-        return r;
-}
-
 int unit_add_default_slice(Unit *u) {
         Unit *slice;
         int r;
@@ -2177,10 +1998,10 @@ int unit_add_default_slice(Unit *u) {
         if (UNIT_ISSET(u->slice))
                 return 0;
 
-        if (u->manager->running_as != SYSTEMD_SYSTEM)
+        if (!unit_get_cgroup_context(u))
                 return 0;
 
-        r = manager_load_unit(u->manager, SPECIAL_SYSTEM_SLICE, NULL, NULL, &slice);
+        r = manager_load_unit(u->manager, u->manager->running_as == SYSTEMD_SYSTEM ? SPECIAL_SYSTEM_SLICE : SPECIAL_ROOT_SLICE, NULL, NULL, &slice);
         if (r < 0)
                 return r;
 
@@ -2197,148 +2018,6 @@ const char *unit_slice_name(Unit *u) {
         return UNIT_DEREF(u->slice)->id;
 }
 
-int unit_add_default_cgroups(Unit *u) {
-        CGroupAttribute *a;
-        char **c;
-        int r;
-
-        assert(u);
-
-        /* Adds in the default cgroups, if they weren't specified
-         * otherwise. */
-
-        if (!u->manager->cgroup_root)
-                return 0;
-
-        r = unit_add_one_default_cgroup(u, NULL);
-        if (r < 0)
-                return r;
-
-        STRV_FOREACH(c, u->manager->default_controllers)
-                unit_add_one_default_cgroup(u, *c);
-
-        LIST_FOREACH(by_unit, a, u->cgroup_attributes)
-                unit_add_one_default_cgroup(u, a->controller);
-
-        return 0;
-}
-
-CGroupBonding* unit_get_default_cgroup(Unit *u) {
-        assert(u);
-
-        return cgroup_bonding_find_list(u->cgroup_bondings, NULL);
-}
-
-int unit_add_cgroup_attribute(
-                Unit *u,
-                const CGroupSemantics *semantics,
-                const char *controller,
-                const char *name,
-                const char *value,
-                CGroupAttribute **ret) {
-
-        _cleanup_free_ char *c = NULL;
-        CGroupAttribute *a;
-        int r;
-
-        assert(u);
-        assert(value);
-
-        if (semantics) {
-                /* Semantics always take precedence */
-                if (semantics->name)
-                        name = semantics->name;
-
-                if (semantics->controller)
-                        controller = semantics->controller;
-        }
-
-        if (!name)
-                return -EINVAL;
-
-        if (!controller) {
-                r = cg_controller_from_attr(name, &c);
-                if (r < 0)
-                        return -EINVAL;
-
-                controller = c;
-        }
-
-        if (!controller ||
-            streq(controller, SYSTEMD_CGROUP_CONTROLLER) ||
-            streq(controller, "systemd"))
-                return -EINVAL;
-
-        if (!filename_is_safe(name))
-                return -EINVAL;
-
-        if (!cg_controller_is_valid(controller, false))
-                return -EINVAL;
-
-        /* Check if this attribute already exists. Note that we will
-         * explicitly check for the value here too, as there are
-         * attributes which accept multiple values. */
-        a = cgroup_attribute_find_list(u->cgroup_attributes, controller, name);
-        if (a) {
-                if (streq(value, a->value)) {
-                        /* Exactly the same value is always OK, let's ignore this */
-                        if (ret)
-                                *ret = a;
-
-                        return 0;
-                }
-
-                if (semantics && !semantics->multiple) {
-                        char *v;
-
-                        /* If this is a single-item entry, we can
-                         * simply patch the existing attribute */
-
-                        v = strdup(value);
-                        if (!v)
-                                return -ENOMEM;
-
-                        free(a->value);
-                        a->value = v;
-
-                        if (ret)
-                                *ret = a;
-                        return 1;
-                }
-        }
-
-        a = new0(CGroupAttribute, 1);
-        if (!a)
-                return -ENOMEM;
-
-        if (c) {
-                a->controller = c;
-                c = NULL;
-        } else
-                a->controller = strdup(controller);
-
-        a->name = strdup(name);
-        a->value = strdup(value);
-
-        if (!a->controller || !a->name || !a->value) {
-                free(a->controller);
-                free(a->name);
-                free(a->value);
-                free(a);
-                return -ENOMEM;
-        }
-
-        a->semantics = semantics;
-        a->unit = u;
-
-        LIST_PREPEND(CGroupAttribute, by_unit, u->cgroup_attributes, a);
-
-        if (ret)
-                *ret = a;
-
-        return 1;
-}
-
 int unit_load_related_unit(Unit *u, const char *type, Unit **_found) {
         _cleanup_free_ char *t = NULL;
         int r;
@@ -2804,7 +2483,7 @@ int unit_kill_common(
                         if (kill(main_pid, signo) < 0)
                                 r = -errno;
 
-        if (who == KILL_ALL) {
+        if (who == KILL_ALL && u->cgroup_path) {
                 _cleanup_set_free_ Set *pid_set = NULL;
                 int q;
 
@@ -2825,7 +2504,7 @@ int unit_kill_common(
                                 return q;
                 }
 
-                q = cgroup_bonding_kill_list(u->cgroup_bondings, signo, false, false, pid_set, NULL);
+                q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, signo, false, true, false, pid_set);
                 if (q < 0 && q != -EAGAIN && q != -ESRCH && q != -ENOENT)
                         r = q;
         }
@@ -2924,7 +2603,6 @@ int unit_exec_context_defaults(Unit *u, ExecContext *c) {
         assert(c);
 
         /* This only copies in the ones that need memory */
-
         for (i = 0; i < RLIMIT_NLIMITS; i++)
                 if (u->manager->rlimit[i] && !c->rlimit[i]) {
                         c->rlimit[i] = newdup(struct rlimit, u->manager->rlimit[i], 1);
@@ -2954,6 +2632,16 @@ ExecContext *unit_get_exec_context(Unit *u) {
         return (ExecContext*) ((uint8_t*) u + offset);
 }
 
+CGroupContext *unit_get_cgroup_context(Unit *u) {
+        size_t offset;
+
+        offset = UNIT_VTABLE(u)->cgroup_context_offset;
+        if (offset <= 0)
+                return NULL;
+
+        return (CGroupContext*) ((uint8_t*) u + offset);
+}
+
 static int drop_in_file(Unit *u, bool runtime, const char *name, char **_p, char **_q) {
         char *p, *q;
         int r;
@@ -3072,7 +2760,7 @@ int unit_kill_context(
                         wait_for_exit = true;
         }
 
-        if (c->kill_mode == KILL_CONTROL_GROUP) {
+        if (c->kill_mode == KILL_CONTROL_GROUP && u->cgroup_path) {
                 _cleanup_set_free_ Set *pid_set = NULL;
 
                 pid_set = set_new(trivial_hash_func, trivial_compare_func);
@@ -3092,7 +2780,7 @@ int unit_kill_context(
                                 return r;
                 }
 
-                r = cgroup_bonding_kill_list(u->cgroup_bondings, sig, true, false, pid_set, NULL);
+                r = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, sig, true, true, false, pid_set);
                 if (r < 0) {
                         if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
                                 log_warning_unit(u->id, "Failed to kill control group: %s", strerror(-r));