src/core/slice.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <stdio.h>
   4
   5 #include "alloc-util.h"
   6 #include "dbus-slice.h"
   7 #include "dbus-unit.h"
   8 #include "log.h"
   9 #include "manager.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.h"
  16 #include "unit-name.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         Slice *s = ASSERT_PTR(SLICE(u));
  25
  26         assert(u->load_state == UNIT_STUB);
  27
  28         u->ignore_on_isolate = true;
  29         s->concurrency_hard_max = UINT_MAX;
  30         s->concurrency_soft_max = UINT_MAX;
  31 }
  32
  33 static void slice_set_state(Slice *s, SliceState state) {
  34         SliceState old_state;
  35
  36         assert(s);
  37
  38         if (s->state != state)
  39                 bus_unit_send_pending_change_signal(UNIT(s), false);
  40
  41         old_state = s->state;
  42         s->state = state;
  43
  44         if (state != old_state)
  45                 log_unit_debug(UNIT(s), "Changed %s -> %s",
  46                                slice_state_to_string(old_state), slice_state_to_string(state));
  47
  48         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], /* reload_success = */ true);
  49 }
  50
  51 static int slice_add_parent_slice(Slice *s) {
  52         Unit *u = UNIT(ASSERT_PTR(s));
  53         _cleanup_free_ char *a = NULL;
  54         int r;
  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 = ASSERT_PTR(SLICE(u));
 155         int r;
 156
 157         assert(u->load_state == UNIT_STUB);
 158
 159         r = slice_load_root_slice(u);
 160         if (r < 0)
 161                 return r;
 162         r = slice_load_system_slice(u);
 163         if (r < 0)
 164                 return r;
 165
 166         r = unit_load_fragment_and_dropin(u, false);
 167         if (r < 0)
 168                 return r;
 169
 170         if (u->load_state != UNIT_LOADED)
 171                 return 0;
 172
 173         /* This is a new unit? Then let's add in some extras */
 174         r = unit_patch_contexts(u);
 175         if (r < 0)
 176                 return r;
 177
 178         r = slice_add_parent_slice(s);
 179         if (r < 0)
 180                 return r;
 181
 182         r = slice_add_default_dependencies(s);
 183         if (r < 0)
 184                 return r;
 185
 186         if (!u->description) {
 187                 _cleanup_free_ char *tmp = NULL;
 188
 189                 r = unit_name_to_path(u->id, &tmp);
 190                 if (r >= 0)  /* Failure is ignored… */
 191                         u->description = strjoin("Slice ", tmp);
 192         }
 193
 194         return slice_verify(s);
 195 }
 196
 197 static int slice_coldplug(Unit *u) {
 198         Slice *s = ASSERT_PTR(SLICE(u));
 199
 200         assert(s->state == SLICE_DEAD);
 201
 202         if (s->deserialized_state != s->state)
 203                 slice_set_state(s, s->deserialized_state);
 204
 205         return 0;
 206 }
 207
 208 static void slice_dump(Unit *u, FILE *f, const char *prefix) {
 209         Slice *s = ASSERT_PTR(SLICE(u));
 210
 211         assert(s);
 212         assert(f);
 213         assert(prefix);
 214
 215         fprintf(f,
 216                 "%sSlice State: %s\n",
 217                 prefix, slice_state_to_string(s->state));
 218
 219         cgroup_context_dump(u, f, prefix);
 220 }
 221
 222 static int slice_start(Unit *u) {
 223         Slice *s = ASSERT_PTR(SLICE(u));
 224         int r;
 225
 226         assert(s->state == SLICE_DEAD);
 227
 228         r = unit_acquire_invocation_id(u);
 229         if (r < 0)
 230                 return r;
 231
 232         (void) unit_realize_cgroup(u);
 233         (void) unit_reset_accounting(u);
 234
 235         slice_set_state(s, SLICE_ACTIVE);
 236         return 1;
 237 }
 238
 239 static int slice_stop(Unit *u) {
 240         Slice *s = ASSERT_PTR(SLICE(u));
 241
 242         assert(s->state == SLICE_ACTIVE);
 243
 244         /* We do not need to destroy the cgroup explicitly,
 245          * unit_notify() will do that for us anyway. */
 246
 247         slice_set_state(s, SLICE_DEAD);
 248         return 1;
 249 }
 250
 251 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 252         Slice *s = ASSERT_PTR(SLICE(u));
 253
 254         assert(f);
 255         assert(fds);
 256
 257         (void) serialize_item(f, "state", slice_state_to_string(s->state));
 258
 259         return 0;
 260 }
 261
 262 static int slice_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 263         Slice *s = ASSERT_PTR(SLICE(u));
 264
 265         assert(key);
 266         assert(value);
 267         assert(fds);
 268
 269         if (streq(key, "state")) {
 270                 SliceState state;
 271
 272                 state = slice_state_from_string(value);
 273                 if (state < 0)
 274                         log_unit_debug(u, "Failed to parse state: %s", value);
 275                 else
 276                         s->deserialized_state = state;
 277
 278         } else
 279                 log_unit_debug(u, "Unknown serialization key: %s", key);
 280
 281         return 0;
 282 }
 283
 284 static UnitActiveState slice_active_state(Unit *u) {
 285         Slice *s = ASSERT_PTR(SLICE(u));
 286
 287         return state_translation_table[s->state];
 288 }
 289
 290 static const char *slice_sub_state_to_string(Unit *u) {
 291         Slice *s = ASSERT_PTR(SLICE(u));
 292
 293         return slice_state_to_string(s->state);
 294 }
 295
 296 static int slice_make_perpetual(Manager *m, const char *name, Unit **ret) {
 297         Unit *u;
 298         int r;
 299
 300         assert(m);
 301         assert(name);
 302
 303         u = manager_get_unit(m, name);
 304         if (!u) {
 305                 r = unit_new_for_name(m, sizeof(Slice), name, &u);
 306                 if (r < 0)
 307                         return log_error_errno(r, "Failed to allocate the special %s unit: %m", name);
 308         }
 309
 310         u->perpetual = true;
 311         SLICE(u)->deserialized_state = SLICE_ACTIVE;
 312
 313         unit_add_to_load_queue(u);
 314         unit_add_to_dbus_queue(u);
 315
 316         if (ret)
 317                 *ret = u;
 318
 319         return 0;
 320 }
 321
 322 static void slice_enumerate_perpetual(Manager *m) {
 323         Unit *u;
 324         int r;
 325
 326         assert(m);
 327
 328         r = slice_make_perpetual(m, SPECIAL_ROOT_SLICE, &u);
 329         if (r >= 0 && manager_owns_host_root_cgroup(m)) {
 330                 Slice *s = SLICE(u);
 331
 332                 /* If we are managing the root cgroup then this means our root slice covers the whole system, which
 333                  * means the kernel will track CPU/tasks/memory for us anyway, and it is all available in /proc. Let's
 334                  * hence turn accounting on here, so that our APIs to query this data are available. */
 335
 336                 s->cgroup_context.tasks_accounting = true;
 337                 s->cgroup_context.memory_accounting = true;
 338         }
 339
 340         if (MANAGER_IS_SYSTEM(m))
 341                 (void) slice_make_perpetual(m, SPECIAL_SYSTEM_SLICE, NULL);
 342 }
 343
 344 static bool slice_can_freeze(const Unit *u) {
 345         assert(u);
 346
 347         Unit *member;
 348         UNIT_FOREACH_DEPENDENCY(member, u, UNIT_ATOM_SLICE_OF)
 349                 if (!unit_can_freeze(member))
 350                         return false;
 351
 352         return true;
 353 }
 354
 355 static int slice_freezer_action(Unit *s, FreezerAction action) {
 356         FreezerAction child_action;
 357         int r;
 358
 359         assert(s);
 360         assert(action >= 0);
 361         assert(action < _FREEZER_ACTION_MAX);
 362
 363         if (action == FREEZER_FREEZE && !slice_can_freeze(s)) {
 364                 /* We're intentionally only checking for FREEZER_FREEZE here and ignoring the
 365                  * _BY_PARENT variant. If we're being frozen by parent, that means someone has
 366                  * already checked if we can be frozen further up the call stack. No point to
 367                  * redo that work */
 368                 log_unit_warning(s, "Requested freezer operation is not supported by all children of the slice.");
 369                 return 0;
 370         }
 371
 372         if (action == FREEZER_FREEZE)
 373                 child_action = FREEZER_PARENT_FREEZE;
 374         else if (action == FREEZER_THAW)
 375                 child_action = FREEZER_PARENT_THAW;
 376         else
 377                 child_action = action;
 378
 379         Unit *member;
 380         UNIT_FOREACH_DEPENDENCY(member, s, UNIT_ATOM_SLICE_OF)
 381                 if (UNIT_VTABLE(member)->freezer_action) {
 382                         r = UNIT_VTABLE(member)->freezer_action(member, child_action);
 383                         if (r < 0)
 384                                 return r;
 385                 }
 386
 387         return unit_cgroup_freezer_action(s, action);
 388 }
 389
 390 unsigned slice_get_currently_active(Slice *slice, Unit *ignore, bool with_pending) {
 391         Unit *u = ASSERT_PTR(UNIT(slice));
 392
 393         /* If 'ignore' is non-NULL and a unit contained in this slice (or any below) we'll ignore it when
 394          * counting. */
 395
 396         unsigned n = 0;
 397         Unit *member;
 398         UNIT_FOREACH_DEPENDENCY(member, u, UNIT_ATOM_SLICE_OF) {
 399                 if (member == ignore)
 400                         continue;
 401
 402                 if (!UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(member)) ||
 403                     (with_pending && member->job && IN_SET(member->job->type, JOB_START, JOB_RESTART, JOB_RELOAD)))
 404                         n++;
 405
 406                 if (member->type == UNIT_SLICE)
 407                         n += slice_get_currently_active(SLICE(member), ignore, with_pending);
 408         }
 409
 410         return n;
 411 }
 412
 413 bool slice_concurrency_soft_max_reached(Slice *slice, Unit *ignore) {
 414         assert(slice);
 415
 416         if (slice->concurrency_soft_max != UINT_MAX &&
 417             slice_get_currently_active(slice, ignore, /* with_pending= */ false) >= slice->concurrency_soft_max)
 418                 return true;
 419
 420         Unit *parent = UNIT_GET_SLICE(UNIT(slice));
 421         if (parent)
 422                 return slice_concurrency_soft_max_reached(SLICE(parent), ignore);
 423
 424         return false;
 425 }
 426
 427 bool slice_concurrency_hard_max_reached(Slice *slice, Unit *ignore) {
 428         assert(slice);
 429
 430         if (slice->concurrency_hard_max != UINT_MAX &&
 431             slice_get_currently_active(slice, ignore, /* with_pending= */ true) >= slice->concurrency_hard_max)
 432                 return true;
 433
 434         Unit *parent = UNIT_GET_SLICE(UNIT(slice));
 435         if (parent)
 436                 return slice_concurrency_hard_max_reached(SLICE(parent), ignore);
 437
 438         return false;
 439 }
 440
 441 const UnitVTable slice_vtable = {
 442         .object_size = sizeof(Slice),
 443         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 444         .cgroup_runtime_offset = offsetof(Slice, cgroup_runtime),
 445
 446         .sections =
 447                 "Unit\0"
 448                 "Slice\0"
 449                 "Install\0",
 450         .private_section = "Slice",
 451
 452         .can_transient = true,
 453         .can_set_managed_oom = true,
 454
 455         .init = slice_init,
 456         .load = slice_load,
 457
 458         .coldplug = slice_coldplug,
 459
 460         .dump = slice_dump,
 461
 462         .start = slice_start,
 463         .stop = slice_stop,
 464
 465         .freezer_action = slice_freezer_action,
 466         .can_freeze = slice_can_freeze,
 467
 468         .serialize = slice_serialize,
 469         .deserialize_item = slice_deserialize_item,
 470
 471         .active_state = slice_active_state,
 472         .sub_state_to_string = slice_sub_state_to_string,
 473
 474         .bus_set_property = bus_slice_set_property,
 475         .bus_commit_properties = bus_slice_commit_properties,
 476
 477         .enumerate_perpetual = slice_enumerate_perpetual,
 478
 479         .status_message_formats = {
 480                 .finished_start_job = {
 481                         [JOB_DONE]       = "Created slice %s.",
 482                 },
 483                 .finished_stop_job = {
 484                         [JOB_DONE]       = "Removed slice %s.",
 485                 },
 486         },
 487 };