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