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], 0);
  47 }
  48
  49 static int slice_add_parent_slice(Slice *s) {
  50         Unit *u = UNIT(s), *parent;
  51         _cleanup_free_ char *a = NULL;
  52         int r;
  53
  54         assert(s);
  55
  56         if (UNIT_ISSET(u->slice))
  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         r = manager_load_unit(u->manager, a, NULL, NULL, &parent);
  64         if (r < 0)
  65                 return r;
  66
  67         unit_ref_set(&u->slice, u, parent);
  68         return 0;
  69 }
  70
  71 static int slice_add_default_dependencies(Slice *s) {
  72         int r;
  73
  74         assert(s);
  75
  76         if (!UNIT(s)->default_dependencies)
  77                 return 0;
  78
  79         /* Make sure slices are unloaded on shutdown */
  80         r = unit_add_two_dependencies_by_name(
  81                         UNIT(s),
  82                         UNIT_BEFORE, UNIT_CONFLICTS,
  83                         SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  84         if (r < 0)
  85                 return r;
  86
  87         return 0;
  88 }
  89
  90 static int slice_verify(Slice *s) {
  91         _cleanup_free_ char *parent = NULL;
  92         int r;
  93
  94         assert(s);
  95         assert(UNIT(s)->load_state == UNIT_LOADED);
  96
  97         if (!slice_name_is_valid(UNIT(s)->id))
  98                 return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(ENOEXEC), "Slice name %s is not valid. Refusing.", UNIT(s)->id);
  99
 100         r = slice_build_parent_slice(UNIT(s)->id, &parent);
 101         if (r < 0)
 102                 return log_unit_error_errno(UNIT(s), r, "Failed to determine parent slice: %m");
 103
 104         if (parent ? !unit_has_name(UNIT_DEREF(UNIT(s)->slice), parent) : UNIT_ISSET(UNIT(s)->slice))
 105                 return log_unit_error_errno(UNIT(s), SYNTHETIC_ERRNO(ENOEXEC), "Located outside of parent slice. Refusing.");
 106
 107         return 0;
 108 }
 109
 110 static int slice_load_root_slice(Unit *u) {
 111         assert(u);
 112
 113         if (!unit_has_name(u, SPECIAL_ROOT_SLICE))
 114                 return 0;
 115
 116         u->perpetual = true;
 117
 118         /* The root slice is a bit special. For example it is always running and cannot be terminated. Because of its
 119          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 120
 121         u->default_dependencies = false;
 122
 123         if (!u->description)
 124                 u->description = strdup("Root Slice");
 125         if (!u->documentation)
 126                 u->documentation = strv_new("man:systemd.special(7)");
 127
 128         return 1;
 129 }
 130
 131 static int slice_load_system_slice(Unit *u) {
 132         assert(u);
 133
 134         if (!MANAGER_IS_SYSTEM(u->manager))
 135                 return 0;
 136         if (!unit_has_name(u, SPECIAL_SYSTEM_SLICE))
 137                 return 0;
 138
 139         u->perpetual = true;
 140
 141         /* The system slice is a bit special. For example it is always running and cannot be terminated. Because of its
 142          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 143
 144         u->default_dependencies = false;
 145
 146         if (!u->description)
 147                 u->description = strdup("System Slice");
 148         if (!u->documentation)
 149                 u->documentation = strv_new("man:systemd.special(7)");
 150
 151         return 1;
 152 }
 153
 154 static int slice_load(Unit *u) {
 155         Slice *s = SLICE(u);
 156         int r;
 157
 158         assert(s);
 159         assert(u->load_state == UNIT_STUB);
 160
 161         r = slice_load_root_slice(u);
 162         if (r < 0)
 163                 return r;
 164         r = slice_load_system_slice(u);
 165         if (r < 0)
 166                 return r;
 167
 168         r = unit_load_fragment_and_dropin(u, false);
 169         if (r < 0)
 170                 return r;
 171
 172         if (u->load_state != UNIT_LOADED)
 173                 return 0;
 174
 175         /* This is a new unit? Then let's add in some extras */
 176         r = unit_patch_contexts(u);
 177         if (r < 0)
 178                 return r;
 179
 180         r = slice_add_parent_slice(s);
 181         if (r < 0)
 182                 return r;
 183
 184         r = slice_add_default_dependencies(s);
 185         if (r < 0)
 186                 return r;
 187
 188         return slice_verify(s);
 189 }
 190
 191 static int slice_coldplug(Unit *u) {
 192         Slice *t = SLICE(u);
 193
 194         assert(t);
 195         assert(t->state == SLICE_DEAD);
 196
 197         if (t->deserialized_state != t->state)
 198                 slice_set_state(t, t->deserialized_state);
 199
 200         return 0;
 201 }
 202
 203 static void slice_dump(Unit *u, FILE *f, const char *prefix) {
 204         Slice *t = SLICE(u);
 205
 206         assert(t);
 207         assert(f);
 208
 209         fprintf(f,
 210                 "%sSlice State: %s\n",
 211                 prefix, slice_state_to_string(t->state));
 212
 213         cgroup_context_dump(UNIT(t), f, prefix);
 214 }
 215
 216 static int slice_start(Unit *u) {
 217         Slice *t = SLICE(u);
 218         int r;
 219
 220         assert(t);
 221         assert(t->state == SLICE_DEAD);
 222
 223         r = unit_acquire_invocation_id(u);
 224         if (r < 0)
 225                 return r;
 226
 227         (void) unit_realize_cgroup(u);
 228         (void) unit_reset_accounting(u);
 229
 230         slice_set_state(t, SLICE_ACTIVE);
 231         return 1;
 232 }
 233
 234 static int slice_stop(Unit *u) {
 235         Slice *t = SLICE(u);
 236
 237         assert(t);
 238         assert(t->state == SLICE_ACTIVE);
 239
 240         /* We do not need to destroy the cgroup explicitly,
 241          * unit_notify() will do that for us anyway. */
 242
 243         slice_set_state(t, SLICE_DEAD);
 244         return 1;
 245 }
 246
 247 static int slice_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 248         return unit_kill_common(u, who, signo, -1, -1, error);
 249 }
 250
 251 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 252         Slice *s = SLICE(u);
 253
 254         assert(s);
 255         assert(f);
 256         assert(fds);
 257
 258         (void) serialize_item(f, "state", slice_state_to_string(s->state));
 259
 260         return 0;
 261 }
 262
 263 static int slice_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 264         Slice *s = SLICE(u);
 265
 266         assert(u);
 267         assert(key);
 268         assert(value);
 269         assert(fds);
 270
 271         if (streq(key, "state")) {
 272                 SliceState state;
 273
 274                 state = slice_state_from_string(value);
 275                 if (state < 0)
 276                         log_debug("Failed to parse state value %s", value);
 277                 else
 278                         s->deserialized_state = state;
 279
 280         } else
 281                 log_debug("Unknown serialization key '%s'", key);
 282
 283         return 0;
 284 }
 285
 286 _pure_ static UnitActiveState slice_active_state(Unit *u) {
 287         assert(u);
 288
 289         return state_translation_table[SLICE(u)->state];
 290 }
 291
 292 _pure_ static const char *slice_sub_state_to_string(Unit *u) {
 293         assert(u);
 294
 295         return slice_state_to_string(SLICE(u)->state);
 296 }
 297
 298 static int slice_make_perpetual(Manager *m, const char *name, Unit **ret) {
 299         Unit *u;
 300         int r;
 301
 302         assert(m);
 303         assert(name);
 304
 305         u = manager_get_unit(m, name);
 306         if (!u) {
 307                 r = unit_new_for_name(m, sizeof(Slice), name, &u);
 308                 if (r < 0)
 309                         return log_error_errno(r, "Failed to allocate the special %s unit: %m", name);
 310         }
 311
 312         u->perpetual = true;
 313         SLICE(u)->deserialized_state = SLICE_ACTIVE;
 314
 315         unit_add_to_load_queue(u);
 316         unit_add_to_dbus_queue(u);
 317
 318         if (ret)
 319                 *ret = u;
 320
 321         return 0;
 322 }
 323
 324 static void slice_enumerate_perpetual(Manager *m) {
 325         Unit *u;
 326         int r;
 327
 328         assert(m);
 329
 330         r = slice_make_perpetual(m, SPECIAL_ROOT_SLICE, &u);
 331         if (r >= 0 && manager_owns_host_root_cgroup(m)) {
 332                 Slice *s = SLICE(u);
 333
 334                 /* If we are managing the root cgroup then this means our root slice covers the whole system, which
 335                  * means the kernel will track CPU/tasks/memory for us anyway, and it is all available in /proc. Let's
 336                  * hence turn accounting on here, so that our APIs to query this data are available. */
 337
 338                 s->cgroup_context.cpu_accounting = true;
 339                 s->cgroup_context.tasks_accounting = true;
 340                 s->cgroup_context.memory_accounting = true;
 341         }
 342
 343         if (MANAGER_IS_SYSTEM(m))
 344                 (void) slice_make_perpetual(m, SPECIAL_SYSTEM_SLICE, NULL);
 345 }
 346
 347 static bool slice_freezer_action_supported_by_children(Unit *s) {
 348         Unit *member;
 349         void *v;
 350
 351         assert(s);
 352
 353         HASHMAP_FOREACH_KEY(v, member, s->dependencies[UNIT_BEFORE]) {
 354                 int r;
 355
 356                 if (UNIT_DEREF(member->slice) != s)
 357                         continue;
 358
 359                 if (member->type == UNIT_SLICE) {
 360                         r = slice_freezer_action_supported_by_children(member);
 361                         if (!r)
 362                                 return r;
 363                 }
 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         void *v;
 375         int r;
 376
 377         assert(s);
 378         assert(IN_SET(action, FREEZER_FREEZE, FREEZER_THAW));
 379
 380         if (!slice_freezer_action_supported_by_children(s)) {
 381                 log_unit_warning(s, "Requested freezer operation is not supported by all children of the slice");
 382                 return 0;
 383         }
 384
 385         HASHMAP_FOREACH_KEY(v, member, s->dependencies[UNIT_BEFORE]) {
 386                 if (UNIT_DEREF(member->slice) != s)
 387                         continue;
 388
 389                 if (action == FREEZER_FREEZE)
 390                         r = UNIT_VTABLE(member)->freeze(member);
 391                 else
 392                         r = UNIT_VTABLE(member)->thaw(member);
 393
 394                 if (r < 0)
 395                         return r;
 396         }
 397
 398         r = unit_cgroup_freezer_action(s, action);
 399         if (r < 0)
 400                 return r;
 401
 402         return 1;
 403 }
 404
 405 static int slice_freeze(Unit *s) {
 406         assert(s);
 407
 408         return slice_freezer_action(s, FREEZER_FREEZE);
 409 }
 410
 411 static int slice_thaw(Unit *s) {
 412         assert(s);
 413
 414         return slice_freezer_action(s, FREEZER_THAW);
 415 }
 416
 417 static bool slice_can_freeze(Unit *s) {
 418         assert(s);
 419
 420         return slice_freezer_action_supported_by_children(s);
 421 }
 422
 423 const UnitVTable slice_vtable = {
 424         .object_size = sizeof(Slice),
 425         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 426
 427         .sections =
 428                 "Unit\0"
 429                 "Slice\0"
 430                 "Install\0",
 431         .private_section = "Slice",
 432
 433         .can_transient = true,
 434         .can_set_managed_oom = true,
 435
 436         .init = slice_init,
 437         .load = slice_load,
 438
 439         .coldplug = slice_coldplug,
 440
 441         .dump = slice_dump,
 442
 443         .start = slice_start,
 444         .stop = slice_stop,
 445
 446         .kill = slice_kill,
 447
 448         .freeze = slice_freeze,
 449         .thaw = slice_thaw,
 450         .can_freeze = slice_can_freeze,
 451
 452         .serialize = slice_serialize,
 453         .deserialize_item = slice_deserialize_item,
 454
 455         .active_state = slice_active_state,
 456         .sub_state_to_string = slice_sub_state_to_string,
 457
 458         .bus_set_property = bus_slice_set_property,
 459         .bus_commit_properties = bus_slice_commit_properties,
 460
 461         .enumerate_perpetual = slice_enumerate_perpetual,
 462
 463         .status_message_formats = {
 464                 .finished_start_job = {
 465                         [JOB_DONE]       = "Created slice %s.",
 466                 },
 467                 .finished_stop_job = {
 468                         [JOB_DONE]       = "Removed slice %s.",
 469                 },
 470         },
 471 };