src/core/slice.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4
   5 #include "alloc-util.h"
   6 #include "dbus-slice.h"
   7 #include "log.h"
   8 #include "serialize.h"
   9 #include "slice.h"
  10 #include "special.h"
  11 #include "string-util.h"
  12 #include "strv.h"
  13 #include "unit-name.h"
  14 #include "unit.h"
  15
  16 static const UnitActiveState state_translation_table[_SLICE_STATE_MAX] = {
  17         [SLICE_DEAD] = UNIT_INACTIVE,
  18         [SLICE_ACTIVE] = UNIT_ACTIVE
  19 };
  20
  21 static void slice_init(Unit *u) {
  22         assert(u);
  23         assert(u->load_state == UNIT_STUB);
  24
  25         u->ignore_on_isolate = true;
  26 }
  27
  28 static void slice_set_state(Slice *t, SliceState state) {
  29         SliceState old_state;
  30         assert(t);
  31
  32         old_state = t->state;
  33         t->state = state;
  34
  35         if (state != old_state)
  36                 log_debug("%s changed %s -> %s",
  37                           UNIT(t)->id,
  38                           slice_state_to_string(old_state),
  39                           slice_state_to_string(state));
  40
  41         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
  42 }
  43
  44 static int slice_add_parent_slice(Slice *s) {
  45         Unit *u = UNIT(s), *parent;
  46         _cleanup_free_ char *a = NULL;
  47         int r;
  48
  49         assert(s);
  50
  51         if (UNIT_ISSET(u->slice))
  52                 return 0;
  53
  54         r = slice_build_parent_slice(u->id, &a);
  55         if (r <= 0) /* 0 means root slice */
  56                 return r;
  57
  58         r = manager_load_unit(u->manager, a, NULL, NULL, &parent);
  59         if (r < 0)
  60                 return r;
  61
  62         unit_ref_set(&u->slice, u, parent);
  63         return 0;
  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
  91         if (UNIT(s)->load_state != UNIT_LOADED)
  92                 return 0;
  93
  94         if (!slice_name_is_valid(UNIT(s)->id)) {
  95                 log_unit_error(UNIT(s), "Slice name %s is not valid. Refusing.", UNIT(s)->id);
  96                 return -ENOEXEC;
  97         }
  98
  99         r = slice_build_parent_slice(UNIT(s)->id, &parent);
 100         if (r < 0)
 101                 return log_unit_error_errno(UNIT(s), r, "Failed to determine parent slice: %m");
 102
 103         if (parent ? !unit_has_name(UNIT_DEREF(UNIT(s)->slice), parent) : UNIT_ISSET(UNIT(s)->slice)) {
 104                 log_unit_error(UNIT(s), "Located outside of parent slice. Refusing.");
 105                 return -ENOEXEC;
 106         }
 107
 108         return 0;
 109 }
 110
 111 static int slice_load_root_slice(Unit *u) {
 112         assert(u);
 113
 114         if (!unit_has_name(u, SPECIAL_ROOT_SLICE))
 115                 return 0;
 116
 117         u->perpetual = true;
 118
 119         /* The root slice is a bit special. For example it is always running and cannot be terminated. Because of its
 120          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 121
 122         u->default_dependencies = false;
 123
 124         if (!u->description)
 125                 u->description = strdup("Root Slice");
 126         if (!u->documentation)
 127                 u->documentation = strv_new("man:systemd.special(7)", NULL);
 128
 129         return 1;
 130 }
 131
 132 static int slice_load_system_slice(Unit *u) {
 133         assert(u);
 134
 135         if (!MANAGER_IS_SYSTEM(u->manager))
 136                 return 0;
 137         if (!unit_has_name(u, SPECIAL_SYSTEM_SLICE))
 138                 return 0;
 139
 140         u->perpetual = true;
 141
 142         /* The system slice is a bit special. For example it is always running and cannot be terminated. Because of its
 143          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 144
 145         u->default_dependencies = false;
 146
 147         if (!u->description)
 148                 u->description = strdup("System Slice");
 149         if (!u->documentation)
 150                 u->documentation = strv_new("man:systemd.special(7)", NULL);
 151
 152         return 1;
 153 }
 154
 155 static int slice_load(Unit *u) {
 156         Slice *s = SLICE(u);
 157         int r;
 158
 159         assert(s);
 160         assert(u->load_state == UNIT_STUB);
 161
 162         r = slice_load_root_slice(u);
 163         if (r < 0)
 164                 return r;
 165         r = slice_load_system_slice(u);
 166         if (r < 0)
 167                 return r;
 168
 169         r = unit_load_fragment_and_dropin_optional(u);
 170         if (r < 0)
 171                 return r;
 172
 173         /* This is a new unit? Then let's add in some extras */
 174         if (u->load_state == UNIT_LOADED) {
 175
 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
 189         return slice_verify(s);
 190 }
 191
 192 static int slice_coldplug(Unit *u) {
 193         Slice *t = SLICE(u);
 194
 195         assert(t);
 196         assert(t->state == SLICE_DEAD);
 197
 198         if (t->deserialized_state != t->state)
 199                 slice_set_state(t, t->deserialized_state);
 200
 201         return 0;
 202 }
 203
 204 static void slice_dump(Unit *u, FILE *f, const char *prefix) {
 205         Slice *t = SLICE(u);
 206
 207         assert(t);
 208         assert(f);
 209
 210         fprintf(f,
 211                 "%sSlice State: %s\n",
 212                 prefix, slice_state_to_string(t->state));
 213
 214         cgroup_context_dump(&t->cgroup_context, f, prefix);
 215 }
 216
 217 static int slice_start(Unit *u) {
 218         Slice *t = SLICE(u);
 219         int r;
 220
 221         assert(t);
 222         assert(t->state == SLICE_DEAD);
 223
 224         r = unit_acquire_invocation_id(u);
 225         if (r < 0)
 226                 return r;
 227
 228         (void) unit_realize_cgroup(u);
 229         (void) unit_reset_cpu_accounting(u);
 230         (void) unit_reset_ip_accounting(u);
 231
 232         slice_set_state(t, SLICE_ACTIVE);
 233         return 1;
 234 }
 235
 236 static int slice_stop(Unit *u) {
 237         Slice *t = SLICE(u);
 238
 239         assert(t);
 240         assert(t->state == SLICE_ACTIVE);
 241
 242         /* We do not need to destroy the cgroup explicitly,
 243          * unit_notify() will do that for us anyway. */
 244
 245         slice_set_state(t, SLICE_DEAD);
 246         return 1;
 247 }
 248
 249 static int slice_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 250         return unit_kill_common(u, who, signo, -1, -1, error);
 251 }
 252
 253 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 254         Slice *s = SLICE(u);
 255
 256         assert(s);
 257         assert(f);
 258         assert(fds);
 259
 260         (void) serialize_item(f, "state", slice_state_to_string(s->state));
 261
 262         return 0;
 263 }
 264
 265 static int slice_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 266         Slice *s = SLICE(u);
 267
 268         assert(u);
 269         assert(key);
 270         assert(value);
 271         assert(fds);
 272
 273         if (streq(key, "state")) {
 274                 SliceState state;
 275
 276                 state = slice_state_from_string(value);
 277                 if (state < 0)
 278                         log_debug("Failed to parse state value %s", value);
 279                 else
 280                         s->deserialized_state = state;
 281
 282         } else
 283                 log_debug("Unknown serialization key '%s'", key);
 284
 285         return 0;
 286 }
 287
 288 _pure_ static UnitActiveState slice_active_state(Unit *u) {
 289         assert(u);
 290
 291         return state_translation_table[SLICE(u)->state];
 292 }
 293
 294 _pure_ static const char *slice_sub_state_to_string(Unit *u) {
 295         assert(u);
 296
 297         return slice_state_to_string(SLICE(u)->state);
 298 }
 299
 300 static int slice_make_perpetual(Manager *m, const char *name, Unit **ret) {
 301         Unit *u;
 302         int r;
 303
 304         assert(m);
 305         assert(name);
 306
 307         u = manager_get_unit(m, name);
 308         if (!u) {
 309                 r = unit_new_for_name(m, sizeof(Slice), name, &u);
 310                 if (r < 0)
 311                         return log_error_errno(r, "Failed to allocate the special %s unit: %m", name);
 312         }
 313
 314         u->perpetual = true;
 315         SLICE(u)->deserialized_state = SLICE_ACTIVE;
 316
 317         unit_add_to_load_queue(u);
 318         unit_add_to_dbus_queue(u);
 319
 320         if (ret)
 321                 *ret = u;
 322
 323         return 0;
 324 }
 325
 326 static void slice_enumerate_perpetual(Manager *m) {
 327         Unit *u;
 328         int r;
 329
 330         assert(m);
 331
 332         r = slice_make_perpetual(m, SPECIAL_ROOT_SLICE, &u);
 333         if (r >= 0 && manager_owns_root_cgroup(m)) {
 334                 Slice *s = SLICE(u);
 335
 336                 /* If we are managing the root cgroup then this means our root slice covers the whole system, which
 337                  * means the kernel will track CPU/tasks/memory for us anyway, and it is all available in /proc. Let's
 338                  * hence turn accounting on here, so that our APIs to query this data are available. */
 339
 340                 s->cgroup_context.cpu_accounting = true;
 341                 s->cgroup_context.tasks_accounting = true;
 342                 s->cgroup_context.memory_accounting = true;
 343         }
 344
 345         if (MANAGER_IS_SYSTEM(m))
 346                 (void) slice_make_perpetual(m, SPECIAL_SYSTEM_SLICE, NULL);
 347 }
 348
 349 const UnitVTable slice_vtable = {
 350         .object_size = sizeof(Slice),
 351         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 352
 353         .sections =
 354                 "Unit\0"
 355                 "Slice\0"
 356                 "Install\0",
 357         .private_section = "Slice",
 358
 359         .can_transient = true,
 360
 361         .init = slice_init,
 362         .load = slice_load,
 363
 364         .coldplug = slice_coldplug,
 365
 366         .dump = slice_dump,
 367
 368         .start = slice_start,
 369         .stop = slice_stop,
 370
 371         .kill = slice_kill,
 372
 373         .serialize = slice_serialize,
 374         .deserialize_item = slice_deserialize_item,
 375
 376         .active_state = slice_active_state,
 377         .sub_state_to_string = slice_sub_state_to_string,
 378
 379         .bus_vtable = bus_slice_vtable,
 380         .bus_set_property = bus_slice_set_property,
 381         .bus_commit_properties = bus_slice_commit_properties,
 382
 383         .enumerate_perpetual = slice_enumerate_perpetual,
 384
 385         .status_message_formats = {
 386                 .finished_start_job = {
 387                         [JOB_DONE]       = "Created slice %s.",
 388                 },
 389                 .finished_stop_job = {
 390                         [JOB_DONE]       = "Removed slice %s.",
 391                 },
 392         },
 393 };