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-rw-r--r--src/core/core-varlink.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/src/core/core-varlink.c b/src/core/core-varlink.c
new file mode 100644
index 0000000..dd6c11a
--- /dev/null
+++ b/src/core/core-varlink.c
@@ -0,0 +1,482 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "core-varlink.h"
+#include "mkdir.h"
+#include "strv.h"
+#include "user-util.h"
+#include "varlink.h"
+
+typedef struct LookupParameters {
+ const char *user_name;
+ const char *group_name;
+ union {
+ uid_t uid;
+ gid_t gid;
+ };
+ const char *service;
+} LookupParameters;
+
+static const char* const managed_oom_mode_properties[] = {
+ "ManagedOOMSwap",
+ "ManagedOOMMemoryPressure",
+};
+
+static int build_user_json(const char *user_name, uid_t uid, JsonVariant **ret) {
+ assert(user_name);
+ assert(uid_is_valid(uid));
+ assert(ret);
+
+ return json_build(ret, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("record", JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(user_name)),
+ JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(uid)),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(uid)),
+ JSON_BUILD_PAIR("realName", JSON_BUILD_STRING("Dynamic User")),
+ JSON_BUILD_PAIR("homeDirectory", JSON_BUILD_STRING("/")),
+ JSON_BUILD_PAIR("shell", JSON_BUILD_STRING(NOLOGIN)),
+ JSON_BUILD_PAIR("locked", JSON_BUILD_BOOLEAN(true)),
+ JSON_BUILD_PAIR("service", JSON_BUILD_STRING("io.systemd.DynamicUser")),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("dynamic"))))));
+}
+
+static bool user_match_lookup_parameters(LookupParameters *p, const char *name, uid_t uid) {
+ assert(p);
+
+ if (p->user_name && !streq(name, p->user_name))
+ return false;
+
+ if (uid_is_valid(p->uid) && uid != p->uid)
+ return false;
+
+ return true;
+}
+
+static int build_managed_oom_json_array_element(Unit *u, const char *property, JsonVariant **ret_v) {
+ bool use_limit = false;
+ CGroupContext *c;
+ const char *mode;
+
+ assert(u);
+ assert(property);
+ assert(ret_v);
+
+ if (!UNIT_VTABLE(u)->can_set_managed_oom)
+ return -EOPNOTSUPP;
+
+ c = unit_get_cgroup_context(u);
+ if (!c)
+ return -EINVAL;
+
+ if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(u)))
+ /* systemd-oomd should always treat inactive units as though they didn't enable any action since they
+ * should not have a valid cgroup */
+ mode = managed_oom_mode_to_string(MANAGED_OOM_AUTO);
+ else if (streq(property, "ManagedOOMSwap"))
+ mode = managed_oom_mode_to_string(c->moom_swap);
+ else if (streq(property, "ManagedOOMMemoryPressure")) {
+ mode = managed_oom_mode_to_string(c->moom_mem_pressure);
+ use_limit = true;
+ } else
+ return -EINVAL;
+
+ return json_build(ret_v, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("mode", JSON_BUILD_STRING(mode)),
+ JSON_BUILD_PAIR("path", JSON_BUILD_STRING(u->cgroup_path)),
+ JSON_BUILD_PAIR("property", JSON_BUILD_STRING(property)),
+ JSON_BUILD_PAIR_CONDITION(use_limit, "limit", JSON_BUILD_UNSIGNED(c->moom_mem_pressure_limit))));
+}
+
+int manager_varlink_send_managed_oom_update(Unit *u) {
+ _cleanup_(json_variant_unrefp) JsonVariant *arr = NULL, *v = NULL;
+ CGroupContext *c;
+ int r;
+
+ assert(u);
+
+ if (!UNIT_VTABLE(u)->can_set_managed_oom || !u->manager || !u->manager->managed_oom_varlink_request || !u->cgroup_path)
+ return 0;
+
+ c = unit_get_cgroup_context(u);
+ if (!c)
+ return 0;
+
+ r = json_build(&arr, JSON_BUILD_EMPTY_ARRAY);
+ if (r < 0)
+ return r;
+
+ for (size_t i = 0; i < ELEMENTSOF(managed_oom_mode_properties); i++) {
+ _cleanup_(json_variant_unrefp) JsonVariant *e = NULL;
+
+ r = build_managed_oom_json_array_element(u, managed_oom_mode_properties[i], &e);
+ if (r < 0)
+ return r;
+
+ r = json_variant_append_array(&arr, e);
+ if (r < 0)
+ return r;
+ }
+
+ r = json_build(&v, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("cgroups", JSON_BUILD_VARIANT(arr))));
+ if (r < 0)
+ return r;
+
+ return varlink_notify(u->manager->managed_oom_varlink_request, v);
+}
+
+static int vl_method_subscribe_managed_oom_cgroups(
+ Varlink *link,
+ JsonVariant *parameters,
+ VarlinkMethodFlags flags,
+ void *userdata) {
+ static const UnitType supported_unit_types[] = { UNIT_SLICE, UNIT_SERVICE, UNIT_SCOPE };
+ _cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *arr = NULL;
+ Manager *m = userdata;
+ int r;
+
+ assert(link);
+ assert(m);
+
+ if (json_variant_elements(parameters) > 0)
+ return varlink_error_invalid_parameter(link, parameters);
+
+ /* We only take one subscriber for this method so return an error if there's already an existing one.
+ * This shouldn't happen since systemd-oomd is the only client of this method. */
+ if (FLAGS_SET(flags, VARLINK_METHOD_MORE) && m->managed_oom_varlink_request)
+ return varlink_error(m->managed_oom_varlink_request, VARLINK_ERROR_SUBSCRIPTION_TAKEN, NULL);
+
+ r = json_build(&arr, JSON_BUILD_EMPTY_ARRAY);
+ if (r < 0)
+ return r;
+
+ for (size_t i = 0; i < ELEMENTSOF(supported_unit_types); i++) {
+ Unit *u;
+
+ LIST_FOREACH(units_by_type, u, m->units_by_type[supported_unit_types[i]]) {
+ CGroupContext *c;
+
+ if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(u)))
+ continue;
+
+ c = unit_get_cgroup_context(u);
+ if (!c)
+ continue;
+
+ for (size_t j = 0; j < ELEMENTSOF(managed_oom_mode_properties); j++) {
+ _cleanup_(json_variant_unrefp) JsonVariant *e = NULL;
+
+ /* For the initial varlink call we only care about units that enabled (i.e. mode is not
+ * set to "auto") oomd properties. */
+ if (!(streq(managed_oom_mode_properties[j], "ManagedOOMSwap") && c->moom_swap == MANAGED_OOM_KILL) &&
+ !(streq(managed_oom_mode_properties[j], "ManagedOOMMemoryPressure") && c->moom_mem_pressure == MANAGED_OOM_KILL))
+ continue;
+
+ r = build_managed_oom_json_array_element(u, managed_oom_mode_properties[j], &e);
+ if (r < 0)
+ return r;
+
+ r = json_variant_append_array(&arr, e);
+ if (r < 0)
+ return r;
+ }
+ }
+ }
+
+ r = json_build(&v, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("cgroups", JSON_BUILD_VARIANT(arr))));
+ if (r < 0)
+ return r;
+
+ if (!FLAGS_SET(flags, VARLINK_METHOD_MORE))
+ return varlink_reply(link, v);
+
+ m->managed_oom_varlink_request = varlink_ref(link);
+ return varlink_notify(m->managed_oom_varlink_request, v);
+}
+
+static int vl_method_get_user_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+
+ static const JsonDispatch dispatch_table[] = {
+ { "uid", JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid, offsetof(LookupParameters, uid), 0 },
+ { "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name), JSON_SAFE },
+ { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 },
+ {}
+ };
+
+ _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+ LookupParameters p = {
+ .uid = UID_INVALID,
+ };
+ _cleanup_free_ char *found_name = NULL;
+ uid_t found_uid = UID_INVALID, uid;
+ Manager *m = userdata;
+ const char *un;
+ int r;
+
+ assert(parameters);
+ assert(m);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+ if (r < 0)
+ return r;
+
+ if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
+ return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+
+ if (uid_is_valid(p.uid))
+ r = dynamic_user_lookup_uid(m, p.uid, &found_name);
+ else if (p.user_name)
+ r = dynamic_user_lookup_name(m, p.user_name, &found_uid);
+ else {
+ DynamicUser *d;
+
+ HASHMAP_FOREACH(d, m->dynamic_users) {
+ r = dynamic_user_current(d, &uid);
+ if (r == -EAGAIN) /* not realized yet? */
+ continue;
+ if (r < 0)
+ return r;
+
+ if (!user_match_lookup_parameters(&p, d->name, uid))
+ continue;
+
+ if (v) {
+ r = varlink_notify(link, v);
+ if (r < 0)
+ return r;
+
+ v = json_variant_unref(v);
+ }
+
+ r = build_user_json(d->name, uid, &v);
+ if (r < 0)
+ return r;
+ }
+
+ if (!v)
+ return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+ return varlink_reply(link, v);
+ }
+ if (r == -ESRCH)
+ return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+ if (r < 0)
+ return r;
+
+ uid = uid_is_valid(found_uid) ? found_uid : p.uid;
+ un = found_name ?: p.user_name;
+
+ if (!user_match_lookup_parameters(&p, un, uid))
+ return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
+
+ r = build_user_json(un, uid, &v);
+ if (r < 0)
+ return r;
+
+ return varlink_reply(link, v);
+}
+
+static int build_group_json(const char *group_name, gid_t gid, JsonVariant **ret) {
+ assert(group_name);
+ assert(gid_is_valid(gid));
+ assert(ret);
+
+ return json_build(ret, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("record", JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(group_name)),
+ JSON_BUILD_PAIR("description", JSON_BUILD_STRING("Dynamic Group")),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(gid)),
+ JSON_BUILD_PAIR("service", JSON_BUILD_STRING("io.systemd.DynamicUser")),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("dynamic"))))));
+ }
+
+static bool group_match_lookup_parameters(LookupParameters *p, const char *name, gid_t gid) {
+ assert(p);
+
+ if (p->group_name && !streq(name, p->group_name))
+ return false;
+
+ if (gid_is_valid(p->gid) && gid != p->gid)
+ return false;
+
+ return true;
+}
+
+static int vl_method_get_group_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+
+ static const JsonDispatch dispatch_table[] = {
+ { "gid", JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid, offsetof(LookupParameters, gid), 0 },
+ { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), JSON_SAFE },
+ { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 },
+ {}
+ };
+
+ _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+ LookupParameters p = {
+ .gid = GID_INVALID,
+ };
+ _cleanup_free_ char *found_name = NULL;
+ uid_t found_gid = GID_INVALID, gid;
+ Manager *m = userdata;
+ const char *gn;
+ int r;
+
+ assert(parameters);
+ assert(m);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+ if (r < 0)
+ return r;
+
+ if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
+ return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+
+ if (gid_is_valid(p.gid))
+ r = dynamic_user_lookup_uid(m, (uid_t) p.gid, &found_name);
+ else if (p.group_name)
+ r = dynamic_user_lookup_name(m, p.group_name, (uid_t*) &found_gid);
+ else {
+ DynamicUser *d;
+
+ HASHMAP_FOREACH(d, m->dynamic_users) {
+ uid_t uid;
+
+ r = dynamic_user_current(d, &uid);
+ if (r == -EAGAIN)
+ continue;
+ if (r < 0)
+ return r;
+
+ if (!group_match_lookup_parameters(&p, d->name, (gid_t) uid))
+ continue;
+
+ if (v) {
+ r = varlink_notify(link, v);
+ if (r < 0)
+ return r;
+
+ v = json_variant_unref(v);
+ }
+
+ r = build_group_json(d->name, (gid_t) uid, &v);
+ if (r < 0)
+ return r;
+ }
+
+ if (!v)
+ return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+ return varlink_reply(link, v);
+ }
+ if (r == -ESRCH)
+ return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+ if (r < 0)
+ return r;
+
+ gid = gid_is_valid(found_gid) ? found_gid : p.gid;
+ gn = found_name ?: p.group_name;
+
+ if (!group_match_lookup_parameters(&p, gn, gid))
+ return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
+
+ r = build_group_json(gn, gid, &v);
+ if (r < 0)
+ return r;
+
+ return varlink_reply(link, v);
+}
+
+static int vl_method_get_memberships(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+
+ static const JsonDispatch dispatch_table[] = {
+ { "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name), JSON_SAFE },
+ { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), JSON_SAFE },
+ { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 },
+ {}
+ };
+
+ LookupParameters p = {};
+ int r;
+
+ assert(parameters);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+ if (r < 0)
+ return r;
+
+ if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
+ return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+
+ /* We don't support auxiliary groups with dynamic users. */
+ return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+}
+
+static void vl_disconnect(VarlinkServer *s, Varlink *link, void *userdata) {
+ Manager *m = userdata;
+
+ assert(m);
+ assert(s);
+ assert(link);
+
+ if (link == m->managed_oom_varlink_request)
+ m->managed_oom_varlink_request = varlink_unref(link);
+}
+
+int manager_varlink_init(Manager *m) {
+ _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL;
+ int r;
+
+ assert(m);
+
+ if (m->varlink_server)
+ return 0;
+
+ if (!MANAGER_IS_SYSTEM(m))
+ return 0;
+
+ r = varlink_server_new(&s, VARLINK_SERVER_ACCOUNT_UID);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate varlink server object: %m");
+
+ varlink_server_set_userdata(s, m);
+
+ r = varlink_server_bind_method_many(
+ s,
+ "io.systemd.UserDatabase.GetUserRecord", vl_method_get_user_record,
+ "io.systemd.UserDatabase.GetGroupRecord", vl_method_get_group_record,
+ "io.systemd.UserDatabase.GetMemberships", vl_method_get_memberships,
+ "io.systemd.ManagedOOM.SubscribeManagedOOMCGroups", vl_method_subscribe_managed_oom_cgroups);
+ if (r < 0)
+ return log_error_errno(r, "Failed to register varlink methods: %m");
+
+ r = varlink_server_bind_disconnect(s, vl_disconnect);
+ if (r < 0)
+ return log_error_errno(r, "Failed to register varlink disconnect handler: %m");
+
+ if (!MANAGER_IS_TEST_RUN(m)) {
+ (void) mkdir_p_label("/run/systemd/userdb", 0755);
+
+ r = varlink_server_listen_address(s, "/run/systemd/userdb/io.systemd.DynamicUser", 0666);
+ if (r < 0)
+ return log_error_errno(r, "Failed to bind to varlink socket: %m");
+
+ r = varlink_server_listen_address(s, VARLINK_ADDR_PATH_MANAGED_OOM, 0666);
+ if (r < 0)
+ return log_error_errno(r, "Failed to bind to varlink socket: %m");
+ }
+
+ r = varlink_server_attach_event(s, m->event, SD_EVENT_PRIORITY_NORMAL);
+ if (r < 0)
+ return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
+
+ m->varlink_server = TAKE_PTR(s);
+ return 0;
+}
+
+void manager_varlink_done(Manager *m) {
+ assert(m);
+
+ /* Send the final message if we still have a subscribe request open. */
+ if (m->managed_oom_varlink_request)
+ m->managed_oom_varlink_request = varlink_close_unref(m->managed_oom_varlink_request);
+
+ m->varlink_server = varlink_server_unref(m->varlink_server);
+}