src/core/slice.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4
   5 #include "alloc-util.h"
   6 #include "dbus-slice.h"
   7 #include "dbus-unit.h"
   8 #include "fd-util.h"
   9 #include "log.h"
  10 #include "serialize.h"
  11 #include "slice.h"
  12 #include "special.h"
  13 #include "string-util.h"
  14 #include "strv.h"
  15 #include "unit-name.h"
  16 #include "unit.h"
  17
  18 static const UnitActiveState state_translation_table[_SLICE_STATE_MAX] = {
  19         [SLICE_DEAD] = UNIT_INACTIVE,
  20         [SLICE_ACTIVE] = UNIT_ACTIVE
  21 };
  22
  23 static void slice_init(Unit *u) {
  24         assert(u);
  25         assert(u->load_state == UNIT_STUB);
  26
  27         u->ignore_on_isolate = true;
  28 }
  29
  30 static void slice_set_state(Slice *t, SliceState state) {
  31         SliceState old_state;
  32         assert(t);
  33
  34         if (t->state != state)
  35                 bus_unit_send_pending_change_signal(UNIT(t), false);
  36
  37         old_state = t->state;
  38         t->state = state;
  39
  40         if (state != old_state)
  41                 log_debug("%s changed %s -> %s",
  42                           UNIT(t)->id,
  43                           slice_state_to_string(old_state),
  44                           slice_state_to_string(state));
  45
  46         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], /* reload_success = */ true);
  47 }
  48
  49 static int slice_add_parent_slice(Slice *s) {
  50         Unit *u = UNIT(s);
  51         _cleanup_free_ char *a = NULL;
  52         int r;
  53
  54         assert(s);
  55
  56         if (UNIT_GET_SLICE(u))
  57                 return 0;
  58
  59         r = slice_build_parent_slice(u->id, &a);
  60         if (r <= 0) /* 0 means root slice */
  61                 return r;
  62
  63         return unit_add_dependency_by_name(u, UNIT_IN_SLICE, a, true, UNIT_DEPENDENCY_IMPLICIT);
  64 }
  65
  66 static int slice_add_default_dependencies(Slice *s) {
  67         int r;
  68
  69         assert(s);
  70
  71         if (!UNIT(s)->default_dependencies)
  72                 return 0;
  73
  74         /* Make sure slices are unloaded on shutdown */
  75         r = unit_add_two_dependencies_by_name(
  76                         UNIT(s),
  77                         UNIT_BEFORE, UNIT_CONFLICTS,
  78                         SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  79         if (r < 0)
  80                 return r;
  81
  82         return 0;
  83 }
  84
  85 static int slice_verify(Slice *s) {
  86         _cleanup_free_ char *parent = NULL;
  87         int r;
  88
  89         assert(s);
  90         assert(UNIT(s)->load_state == UNIT_LOADED);
  91
  92         if (!slice_name_is_valid(UNIT(s)->id))
  93                 return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(ENOEXEC), "Slice name %s is not valid. Refusing.", UNIT(s)->id);
  94
  95         r = slice_build_parent_slice(UNIT(s)->id, &parent);
  96         if (r < 0)
  97                 return log_unit_error_errno(UNIT(s), r, "Failed to determine parent slice: %m");
  98
  99         /* If recursive errors are to be ignored, the parent slice should not be verified */
 100         if (UNIT(s)->manager && FLAGS_SET(UNIT(s)->manager->test_run_flags, MANAGER_TEST_RUN_IGNORE_DEPENDENCIES))
 101                 return 0;
 102
 103         if (parent ? !unit_has_name(UNIT_GET_SLICE(UNIT(s)), parent) : !!UNIT_GET_SLICE(UNIT(s)))
 104                 return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(ENOEXEC), "Located outside of parent slice. Refusing.");
 105
 106         return 0;
 107 }
 108
 109 static int slice_load_root_slice(Unit *u) {
 110         assert(u);
 111
 112         if (!unit_has_name(u, SPECIAL_ROOT_SLICE))
 113                 return 0;
 114
 115         u->perpetual = true;
 116
 117         /* The root slice is a bit special. For example it is always running and cannot be terminated. Because of its
 118          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 119
 120         u->default_dependencies = false;
 121
 122         if (!u->description)
 123                 u->description = strdup("Root Slice");
 124         if (!u->documentation)
 125                 u->documentation = strv_new("man:systemd.special(7)");
 126
 127         return 1;
 128 }
 129
 130 static int slice_load_system_slice(Unit *u) {
 131         assert(u);
 132
 133         if (!MANAGER_IS_SYSTEM(u->manager))
 134                 return 0;
 135         if (!unit_has_name(u, SPECIAL_SYSTEM_SLICE))
 136                 return 0;
 137
 138         u->perpetual = true;
 139
 140         /* The system slice is a bit special. For example it is always running and cannot be terminated. Because of its
 141          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 142
 143         u->default_dependencies = false;
 144
 145         if (!u->description)
 146                 u->description = strdup("System Slice");
 147         if (!u->documentation)
 148                 u->documentation = strv_new("man:systemd.special(7)");
 149
 150         return 1;
 151 }
 152
 153 static int slice_load(Unit *u) {
 154         Slice *s = SLICE(u);
 155         int r;
 156
 157         assert(s);
 158         assert(u->load_state == UNIT_STUB);
 159
 160         r = slice_load_root_slice(u);
 161         if (r < 0)
 162                 return r;
 163         r = slice_load_system_slice(u);
 164         if (r < 0)
 165                 return r;
 166
 167         r = unit_load_fragment_and_dropin(u, false);
 168         if (r < 0)
 169                 return r;
 170
 171         if (u->load_state != UNIT_LOADED)
 172                 return 0;
 173
 174         /* This is a new unit? Then let's add in some extras */
 175         r = unit_patch_contexts(u);
 176         if (r < 0)
 177                 return r;
 178
 179         r = slice_add_parent_slice(s);
 180         if (r < 0)
 181                 return r;
 182
 183         r = slice_add_default_dependencies(s);
 184         if (r < 0)
 185                 return r;
 186
 187         if (!u->description) {
 188                 _cleanup_free_ char *tmp = NULL;
 189
 190                 r = unit_name_to_path(u->id, &tmp);
 191                 if (r >= 0)  /* Failure is ignored… */
 192                         u->description = strjoin("Slice ", tmp);
 193         }
 194
 195         return slice_verify(s);
 196 }
 197
 198 static int slice_coldplug(Unit *u) {
 199         Slice *t = SLICE(u);
 200
 201         assert(t);
 202         assert(t->state == SLICE_DEAD);
 203
 204         if (t->deserialized_state != t->state)
 205                 slice_set_state(t, t->deserialized_state);
 206
 207         return 0;
 208 }
 209
 210 static void slice_dump(Unit *u, FILE *f, const char *prefix) {
 211         Slice *t = SLICE(u);
 212
 213         assert(t);
 214         assert(f);
 215
 216         fprintf(f,
 217                 "%sSlice State: %s\n",
 218                 prefix, slice_state_to_string(t->state));
 219
 220         cgroup_context_dump(UNIT(t), f, prefix);
 221 }
 222
 223 static int slice_start(Unit *u) {
 224         Slice *t = SLICE(u);
 225         int r;
 226
 227         assert(t);
 228         assert(t->state == SLICE_DEAD);
 229
 230         r = unit_acquire_invocation_id(u);
 231         if (r < 0)
 232                 return r;
 233
 234         (void) unit_realize_cgroup(u);
 235         (void) unit_reset_accounting(u);
 236
 237         slice_set_state(t, SLICE_ACTIVE);
 238         return 1;
 239 }
 240
 241 static int slice_stop(Unit *u) {
 242         Slice *t = SLICE(u);
 243
 244         assert(t);
 245         assert(t->state == SLICE_ACTIVE);
 246
 247         /* We do not need to destroy the cgroup explicitly,
 248          * unit_notify() will do that for us anyway. */
 249
 250         slice_set_state(t, SLICE_DEAD);
 251         return 1;
 252 }
 253
 254 static int slice_kill(Unit *u, KillWho who, int signo, int code, int value, sd_bus_error *error) {
 255         return unit_kill_common(u, who, signo, code, value, -1, -1, error);
 256 }
 257
 258 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 259         Slice *s = SLICE(u);
 260
 261         assert(s);
 262         assert(f);
 263         assert(fds);
 264
 265         (void) serialize_item(f, "state", slice_state_to_string(s->state));
 266
 267         return 0;
 268 }
 269
 270 static int slice_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 271         Slice *s = SLICE(u);
 272
 273         assert(u);
 274         assert(key);
 275         assert(value);
 276         assert(fds);
 277
 278         if (streq(key, "state")) {
 279                 SliceState state;
 280
 281                 state = slice_state_from_string(value);
 282                 if (state < 0)
 283                         log_debug("Failed to parse state value %s", value);
 284                 else
 285                         s->deserialized_state = state;
 286
 287         } else
 288                 log_debug("Unknown serialization key '%s'", key);
 289
 290         return 0;
 291 }
 292
 293 _pure_ static UnitActiveState slice_active_state(Unit *u) {
 294         assert(u);
 295
 296         return state_translation_table[SLICE(u)->state];
 297 }
 298
 299 _pure_ static const char *slice_sub_state_to_string(Unit *u) {
 300         assert(u);
 301
 302         return slice_state_to_string(SLICE(u)->state);
 303 }
 304
 305 static int slice_make_perpetual(Manager *m, const char *name, Unit **ret) {
 306         Unit *u;
 307         int r;
 308
 309         assert(m);
 310         assert(name);
 311
 312         u = manager_get_unit(m, name);
 313         if (!u) {
 314                 r = unit_new_for_name(m, sizeof(Slice), name, &u);
 315                 if (r < 0)
 316                         return log_error_errno(r, "Failed to allocate the special %s unit: %m", name);
 317         }
 318
 319         u->perpetual = true;
 320         SLICE(u)->deserialized_state = SLICE_ACTIVE;
 321
 322         unit_add_to_load_queue(u);
 323         unit_add_to_dbus_queue(u);
 324
 325         if (ret)
 326                 *ret = u;
 327
 328         return 0;
 329 }
 330
 331 static void slice_enumerate_perpetual(Manager *m) {
 332         Unit *u;
 333         int r;
 334
 335         assert(m);
 336
 337         r = slice_make_perpetual(m, SPECIAL_ROOT_SLICE, &u);
 338         if (r >= 0 && manager_owns_host_root_cgroup(m)) {
 339                 Slice *s = SLICE(u);
 340
 341                 /* If we are managing the root cgroup then this means our root slice covers the whole system, which
 342                  * means the kernel will track CPU/tasks/memory for us anyway, and it is all available in /proc. Let's
 343                  * hence turn accounting on here, so that our APIs to query this data are available. */
 344
 345                 s->cgroup_context.cpu_accounting = true;
 346                 s->cgroup_context.tasks_accounting = true;
 347                 s->cgroup_context.memory_accounting = true;
 348         }
 349
 350         if (MANAGER_IS_SYSTEM(m))
 351                 (void) slice_make_perpetual(m, SPECIAL_SYSTEM_SLICE, NULL);
 352 }
 353
 354 static bool slice_freezer_action_supported_by_children(Unit *s) {
 355         Unit *member;
 356
 357         assert(s);
 358
 359         UNIT_FOREACH_DEPENDENCY(member, s, UNIT_ATOM_SLICE_OF) {
 360
 361                 if (member->type == UNIT_SLICE &&
 362                     !slice_freezer_action_supported_by_children(member))
 363                         return false;
 364
 365                 if (!UNIT_VTABLE(member)->freeze)
 366                         return false;
 367         }
 368
 369         return true;
 370 }
 371
 372 static int slice_freezer_action(Unit *s, FreezerAction action) {
 373         Unit *member;
 374         int r;
 375
 376         assert(s);
 377         assert(IN_SET(action, FREEZER_FREEZE, FREEZER_THAW));
 378
 379         if (action == FREEZER_FREEZE && !slice_freezer_action_supported_by_children(s)) {
 380                 log_unit_warning(s, "Requested freezer operation is not supported by all children of the slice");
 381                 return 0;
 382         }
 383
 384         UNIT_FOREACH_DEPENDENCY(member, s, UNIT_ATOM_SLICE_OF) {
 385                 if (!member->cgroup_realized)
 386                         continue;
 387
 388                 if (action == FREEZER_FREEZE)
 389                         r = UNIT_VTABLE(member)->freeze(member);
 390                 else if (UNIT_VTABLE(member)->thaw)
 391                         r = UNIT_VTABLE(member)->thaw(member);
 392                 else
 393                         /* Thawing is requested but no corresponding method is available, ignore. */
 394                         r = 0;
 395                 if (r < 0)
 396                         return r;
 397         }
 398
 399         return unit_cgroup_freezer_action(s, action);
 400 }
 401
 402 static int slice_freeze(Unit *s) {
 403         assert(s);
 404
 405         return slice_freezer_action(s, FREEZER_FREEZE);
 406 }
 407
 408 static int slice_thaw(Unit *s) {
 409         assert(s);
 410
 411         return slice_freezer_action(s, FREEZER_THAW);
 412 }
 413
 414 static bool slice_can_freeze(Unit *s) {
 415         assert(s);
 416
 417         return slice_freezer_action_supported_by_children(s);
 418 }
 419
 420 const UnitVTable slice_vtable = {
 421         .object_size = sizeof(Slice),
 422         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 423
 424         .sections =
 425                 "Unit\0"
 426                 "Slice\0"
 427                 "Install\0",
 428         .private_section = "Slice",
 429
 430         .can_transient = true,
 431         .can_set_managed_oom = true,
 432
 433         .init = slice_init,
 434         .load = slice_load,
 435
 436         .coldplug = slice_coldplug,
 437
 438         .dump = slice_dump,
 439
 440         .start = slice_start,
 441         .stop = slice_stop,
 442
 443         .kill = slice_kill,
 444
 445         .freeze = slice_freeze,
 446         .thaw = slice_thaw,
 447         .can_freeze = slice_can_freeze,
 448
 449         .serialize = slice_serialize,
 450         .deserialize_item = slice_deserialize_item,
 451
 452         .active_state = slice_active_state,
 453         .sub_state_to_string = slice_sub_state_to_string,
 454
 455         .bus_set_property = bus_slice_set_property,
 456         .bus_commit_properties = bus_slice_commit_properties,
 457
 458         .enumerate_perpetual = slice_enumerate_perpetual,
 459
 460         .status_message_formats = {
 461                 .finished_start_job = {
 462                         [JOB_DONE]       = "Created slice %s.",
 463                 },
 464                 .finished_stop_job = {
 465                         [JOB_DONE]       = "Removed slice %s.",
 466                 },
 467         },
 468 };