diff options
Diffstat (limited to 'src/core/core-varlink.c')
| -rw-r--r-- | src/core/core-varlink.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/src/core/core-varlink.c b/src/core/core-varlink.c new file mode 100644 index 0000000..8432715 --- /dev/null +++ b/src/core/core-varlink.c @@ -0,0 +1,630 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "core-varlink.h" +#include "mkdir-label.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_CONST_STRING("Dynamic User")), + JSON_BUILD_PAIR("homeDirectory", JSON_BUILD_CONST_STRING("/")), + JSON_BUILD_PAIR("shell", JSON_BUILD_CONST_STRING(NOLOGIN)), + JSON_BUILD_PAIR("locked", JSON_BUILD_BOOLEAN(true)), + JSON_BUILD_PAIR("service", JSON_BUILD_CONST_STRING("io.systemd.DynamicUser")), + JSON_BUILD_PAIR("disposition", JSON_BUILD_CONST_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->cgroup_path) + return 0; + + if (MANAGER_IS_SYSTEM(u->manager)) { + /* In system mode we can't send any notifications unless oomd connected back to us. In this + * mode oomd must initiate communication, not us. */ + if (!u->manager->managed_oom_varlink) + return 0; + } else { + /* If we are in user mode, let's connect to oomd if we aren't connected yet. In this mode we + * must initiate communication to oomd, not the other way round. */ + r = manager_varlink_init(u->manager); + if (r <= 0) + return r; + } + + 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; + + if (MANAGER_IS_SYSTEM(u->manager)) + /* in system mode, oomd is our client, thus send out notifications as replies to the + * initiating method call from them. */ + r = varlink_notify(u->manager->managed_oom_varlink, v); + else + /* in user mode, we are oomd's client, thus send out notifications as method calls that do + * not expect a reply. */ + r = varlink_send(u->manager->managed_oom_varlink, "io.systemd.oom.ReportManagedOOMCGroups", v); + + return r; +} + +static int build_managed_oom_cgroups_json(Manager *m, JsonVariant **ret) { + static const UnitType supported_unit_types[] = { UNIT_SLICE, UNIT_SERVICE, UNIT_SCOPE }; + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *arr = NULL; + int r; + + assert(m); + assert(ret); + + r = json_build(&arr, JSON_BUILD_EMPTY_ARRAY); + if (r < 0) + return r; + + for (size_t i = 0; i < ELEMENTSOF(supported_unit_types); i++) + 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; + + *ret = TAKE_PTR(v); + return 0; +} + +static int vl_method_subscribe_managed_oom_cgroups( + Varlink *link, + JsonVariant *parameters, + VarlinkMethodFlags flags, + void *userdata) { + + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + Manager *m = ASSERT_PTR(userdata); + pid_t pid; + Unit *u; + int r; + + assert(link); + + r = varlink_get_peer_pid(link, &pid); + if (r < 0) + return r; + + u = manager_get_unit_by_pid(m, pid); + if (!u) + return varlink_error(link, VARLINK_ERROR_PERMISSION_DENIED, NULL); + + /* This is meant to be a deterrent and not actual security. The alternative is to check for the systemd-oom + * user that this unit runs as, but NSS lookups are blocking and not allowed from PID 1. */ + if (!streq(u->id, "systemd-oomd.service")) + return varlink_error(link, VARLINK_ERROR_PERMISSION_DENIED, NULL); + + 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) + return varlink_error(link, VARLINK_ERROR_SUBSCRIPTION_TAKEN, NULL); + + r = build_managed_oom_cgroups_json(m, &v); + if (r < 0) + return r; + + if (!FLAGS_SET(flags, VARLINK_METHOD_MORE)) + return varlink_reply(link, v); + + assert(!m->managed_oom_varlink); + m->managed_oom_varlink = varlink_ref(link); + return varlink_notify(m->managed_oom_varlink, v); +} + +static int manager_varlink_send_managed_oom_initial(Manager *m) { + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + int r; + + assert(m); + + if (MANAGER_IS_SYSTEM(m)) + return 0; + + assert(m->managed_oom_varlink); + + r = build_managed_oom_cgroups_json(m, &v); + if (r < 0) + return r; + + return varlink_send(m->managed_oom_varlink, "io.systemd.oom.ReportManagedOOMCGroups", 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 = ASSERT_PTR(userdata); + const char *un; + 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); + + 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_CONST_STRING("Dynamic Group")), + JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(gid)), + JSON_BUILD_PAIR("service", JSON_BUILD_CONST_STRING("io.systemd.DynamicUser")), + JSON_BUILD_PAIR("disposition", JSON_BUILD_CONST_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 = ASSERT_PTR(userdata); + const char *gn; + 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); + + 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 = ASSERT_PTR(userdata); + + assert(s); + assert(link); + + if (link == m->managed_oom_varlink) + m->managed_oom_varlink = varlink_unref(link); +} + +static int manager_varlink_init_system(Manager *m) { + _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL; + int r; + + assert(m); + + if (m->varlink_server) + return 1; + + if (!MANAGER_IS_SYSTEM(m)) + return 0; + + r = manager_setup_varlink_server(m, &s); + if (r < 0) + return log_error_errno(r, "Failed to set up varlink server: %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_SYSTEM, 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 1; +} + +static int vl_reply(Varlink *link, JsonVariant *parameters, const char *error_id, VarlinkReplyFlags flags, void *userdata) { + Manager *m = ASSERT_PTR(userdata); + int r; + + if (error_id) + log_debug("varlink systemd-oomd client error: %s", error_id); + + if (FLAGS_SET(flags, VARLINK_REPLY_ERROR) && FLAGS_SET(flags, VARLINK_REPLY_LOCAL)) { + /* Varlink connection was closed, likely because of systemd-oomd restart. Let's try to + * reconnect and send the initial ManagedOOM update again. */ + + m->managed_oom_varlink = varlink_unref(link); + + log_debug("Reconnecting to %s", VARLINK_ADDR_PATH_MANAGED_OOM_USER); + + r = manager_varlink_init(m); + if (r <= 0) + return r; + } + + return 0; +} + +static int manager_varlink_init_user(Manager *m) { + _cleanup_(varlink_close_unrefp) Varlink *link = NULL; + int r; + + assert(m); + + if (m->managed_oom_varlink) + return 1; + + if (MANAGER_IS_TEST_RUN(m)) + return 0; + + r = varlink_connect_address(&link, VARLINK_ADDR_PATH_MANAGED_OOM_USER); + if (r == -ENOENT || ERRNO_IS_DISCONNECT(r)) { + log_debug("systemd-oomd varlink unix socket not found, skipping user manager varlink setup"); + return 0; + } + if (r < 0) + return log_error_errno(r, "Failed to connect to %s: %m", VARLINK_ADDR_PATH_MANAGED_OOM_USER); + + varlink_set_userdata(link, m); + + r = varlink_bind_reply(link, vl_reply); + if (r < 0) + return r; + + r = varlink_attach_event(link, m->event, SD_EVENT_PRIORITY_NORMAL); + if (r < 0) + return log_error_errno(r, "Failed to attach varlink connection to event loop: %m"); + + m->managed_oom_varlink = TAKE_PTR(link); + + /* Queue the initial ManagedOOM update. */ + (void) manager_varlink_send_managed_oom_initial(m); + + return 1; +} + +int manager_setup_varlink_server(Manager *m, VarlinkServer **ret) { + _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL; + int r; + + assert(m); + assert(ret); + + r = varlink_server_new(&s, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA); + if (r < 0) + return log_debug_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_debug_errno(r, "Failed to register varlink methods: %m"); + + r = varlink_server_bind_disconnect(s, vl_disconnect); + if (r < 0) + return log_debug_errno(r, "Failed to register varlink disconnect handler: %m"); + + *ret = TAKE_PTR(s); + return 0; +} + +int manager_varlink_init(Manager *m) { + return MANAGER_IS_SYSTEM(m) ? manager_varlink_init_system(m) : manager_varlink_init_user(m); +} + +void manager_varlink_done(Manager *m) { + assert(m); + + /* Explicitly close the varlink connection to oomd. Note we first take the varlink connection out of + * the manager, and only then disconnect it — in two steps – so that we don't end up accidentally + * unreffing it twice. After all, closing the connection might cause the disconnect handler we + * installed (vl_disconnect() above) to be called, where we will unref it too. */ + varlink_close_unref(TAKE_PTR(m->managed_oom_varlink)); + + m->varlink_server = varlink_server_unref(m->varlink_server); + m->managed_oom_varlink = varlink_close_unref(m->managed_oom_varlink); +} |