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 "dbus-unit.h"
   8 #include "log.h"
   9 #include "serialize.h"
  10 #include "slice.h"
  11 #include "special.h"
  12 #include "string-util.h"
  13 #include "strv.h"
  14 #include "unit-name.h"
  15 #include "unit.h"
  16
  17 static const UnitActiveState state_translation_table[_SLICE_STATE_MAX] = {
  18         [SLICE_DEAD] = UNIT_INACTIVE,
  19         [SLICE_ACTIVE] = UNIT_ACTIVE
  20 };
  21
  22 static void slice_init(Unit *u) {
  23         assert(u);
  24         assert(u->load_state == UNIT_STUB);
  25
  26         u->ignore_on_isolate = true;
  27 }
  28
  29 static void slice_set_state(Slice *t, SliceState state) {
  30         SliceState old_state;
  31         assert(t);
  32
  33         if (t->state != state)
  34                 bus_unit_send_pending_change_signal(UNIT(t), false);
  35
  36         old_state = t->state;
  37         t->state = state;
  38
  39         if (state != old_state)
  40                 log_debug("%s changed %s -> %s",
  41                           UNIT(t)->id,
  42                           slice_state_to_string(old_state),
  43                           slice_state_to_string(state));
  44
  45         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
  46 }
  47
  48 static int slice_add_parent_slice(Slice *s) {
  49         Unit *u = UNIT(s), *parent;
  50         _cleanup_free_ char *a = NULL;
  51         int r;
  52
  53         assert(s);
  54
  55         if (UNIT_ISSET(u->slice))
  56                 return 0;
  57
  58         r = slice_build_parent_slice(u->id, &a);
  59         if (r <= 0) /* 0 means root slice */
  60                 return r;
  61
  62         r = manager_load_unit(u->manager, a, NULL, NULL, &parent);
  63         if (r < 0)
  64                 return r;
  65
  66         unit_ref_set(&u->slice, u, parent);
  67         return 0;
  68 }
  69
  70 static int slice_add_default_dependencies(Slice *s) {
  71         int r;
  72
  73         assert(s);
  74
  75         if (!UNIT(s)->default_dependencies)
  76                 return 0;
  77
  78         /* Make sure slices are unloaded on shutdown */
  79         r = unit_add_two_dependencies_by_name(
  80                         UNIT(s),
  81                         UNIT_BEFORE, UNIT_CONFLICTS,
  82                         SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  83         if (r < 0)
  84                 return r;
  85
  86         return 0;
  87 }
  88
  89 static int slice_verify(Slice *s) {
  90         _cleanup_free_ char *parent = NULL;
  91         int r;
  92
  93         assert(s);
  94
  95         if (UNIT(s)->load_state != UNIT_LOADED)
  96                 return 0;
  97
  98         if (!slice_name_is_valid(UNIT(s)->id)) {
  99                 log_unit_error(UNIT(s), "Slice name %s is not valid. Refusing.", UNIT(s)->id);
 100                 return -ENOEXEC;
 101         }
 102
 103         r = slice_build_parent_slice(UNIT(s)->id, &parent);
 104         if (r < 0)
 105                 return log_unit_error_errno(UNIT(s), r, "Failed to determine parent slice: %m");
 106
 107         if (parent ? !unit_has_name(UNIT_DEREF(UNIT(s)->slice), parent) : UNIT_ISSET(UNIT(s)->slice)) {
 108                 log_unit_error(UNIT(s), "Located outside of parent slice. Refusing.");
 109                 return -ENOEXEC;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int slice_load_root_slice(Unit *u) {
 116         assert(u);
 117
 118         if (!unit_has_name(u, SPECIAL_ROOT_SLICE))
 119                 return 0;
 120
 121         u->perpetual = true;
 122
 123         /* The root slice is a bit special. For example it is always running and cannot be terminated. Because of its
 124          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 125
 126         u->default_dependencies = false;
 127
 128         if (!u->description)
 129                 u->description = strdup("Root Slice");
 130         if (!u->documentation)
 131                 u->documentation = strv_new("man:systemd.special(7)");
 132
 133         return 1;
 134 }
 135
 136 static int slice_load_system_slice(Unit *u) {
 137         assert(u);
 138
 139         if (!MANAGER_IS_SYSTEM(u->manager))
 140                 return 0;
 141         if (!unit_has_name(u, SPECIAL_SYSTEM_SLICE))
 142                 return 0;
 143
 144         u->perpetual = true;
 145
 146         /* The system slice is a bit special. For example it is always running and cannot be terminated. Because of its
 147          * special semantics we synthesize it here, instead of relying on the unit file on disk. */
 148
 149         u->default_dependencies = false;
 150
 151         if (!u->description)
 152                 u->description = strdup("System Slice");
 153         if (!u->documentation)
 154                 u->documentation = strv_new("man:systemd.special(7)");
 155
 156         return 1;
 157 }
 158
 159 static int slice_load(Unit *u) {
 160         Slice *s = SLICE(u);
 161         int r;
 162
 163         assert(s);
 164         assert(u->load_state == UNIT_STUB);
 165
 166         r = slice_load_root_slice(u);
 167         if (r < 0)
 168                 return r;
 169         r = slice_load_system_slice(u);
 170         if (r < 0)
 171                 return r;
 172
 173         r = unit_load_fragment_and_dropin_optional(u);
 174         if (r < 0)
 175                 return r;
 176
 177         /* This is a new unit? Then let's add in some extras */
 178         if (u->load_state == UNIT_LOADED) {
 179
 180                 r = unit_patch_contexts(u);
 181                 if (r < 0)
 182                         return r;
 183
 184                 r = slice_add_parent_slice(s);
 185                 if (r < 0)
 186                         return r;
 187
 188                 r = slice_add_default_dependencies(s);
 189                 if (r < 0)
 190                         return r;
 191         }
 192
 193         return slice_verify(s);
 194 }
 195
 196 static int slice_coldplug(Unit *u) {
 197         Slice *t = SLICE(u);
 198
 199         assert(t);
 200         assert(t->state == SLICE_DEAD);
 201
 202         if (t->deserialized_state != t->state)
 203                 slice_set_state(t, t->deserialized_state);
 204
 205         return 0;
 206 }
 207
 208 static void slice_dump(Unit *u, FILE *f, const char *prefix) {
 209         Slice *t = SLICE(u);
 210
 211         assert(t);
 212         assert(f);
 213
 214         fprintf(f,
 215                 "%sSlice State: %s\n",
 216                 prefix, slice_state_to_string(t->state));
 217
 218         cgroup_context_dump(&t->cgroup_context, f, prefix);
 219 }
 220
 221 static int slice_start(Unit *u) {
 222         Slice *t = SLICE(u);
 223         int r;
 224
 225         assert(t);
 226         assert(t->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(t, SLICE_ACTIVE);
 236         return 1;
 237 }
 238
 239 static int slice_stop(Unit *u) {
 240         Slice *t = SLICE(u);
 241
 242         assert(t);
 243         assert(t->state == SLICE_ACTIVE);
 244
 245         /* We do not need to destroy the cgroup explicitly,
 246          * unit_notify() will do that for us anyway. */
 247
 248         slice_set_state(t, SLICE_DEAD);
 249         return 1;
 250 }
 251
 252 static int slice_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 253         return unit_kill_common(u, who, signo, -1, -1, error);
 254 }
 255
 256 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 257         Slice *s = SLICE(u);
 258
 259         assert(s);
 260         assert(f);
 261         assert(fds);
 262
 263         (void) serialize_item(f, "state", slice_state_to_string(s->state));
 264
 265         return 0;
 266 }
 267
 268 static int slice_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 269         Slice *s = SLICE(u);
 270
 271         assert(u);
 272         assert(key);
 273         assert(value);
 274         assert(fds);
 275
 276         if (streq(key, "state")) {
 277                 SliceState state;
 278
 279                 state = slice_state_from_string(value);
 280                 if (state < 0)
 281                         log_debug("Failed to parse state value %s", value);
 282                 else
 283                         s->deserialized_state = state;
 284
 285         } else
 286                 log_debug("Unknown serialization key '%s'", key);
 287
 288         return 0;
 289 }
 290
 291 _pure_ static UnitActiveState slice_active_state(Unit *u) {
 292         assert(u);
 293
 294         return state_translation_table[SLICE(u)->state];
 295 }
 296
 297 _pure_ static const char *slice_sub_state_to_string(Unit *u) {
 298         assert(u);
 299
 300         return slice_state_to_string(SLICE(u)->state);
 301 }
 302
 303 static int slice_make_perpetual(Manager *m, const char *name, Unit **ret) {
 304         Unit *u;
 305         int r;
 306
 307         assert(m);
 308         assert(name);
 309
 310         u = manager_get_unit(m, name);
 311         if (!u) {
 312                 r = unit_new_for_name(m, sizeof(Slice), name, &u);
 313                 if (r < 0)
 314                         return log_error_errno(r, "Failed to allocate the special %s unit: %m", name);
 315         }
 316
 317         u->perpetual = true;
 318         SLICE(u)->deserialized_state = SLICE_ACTIVE;
 319
 320         unit_add_to_load_queue(u);
 321         unit_add_to_dbus_queue(u);
 322
 323         if (ret)
 324                 *ret = u;
 325
 326         return 0;
 327 }
 328
 329 static void slice_enumerate_perpetual(Manager *m) {
 330         Unit *u;
 331         int r;
 332
 333         assert(m);
 334
 335         r = slice_make_perpetual(m, SPECIAL_ROOT_SLICE, &u);
 336         if (r >= 0 && manager_owns_host_root_cgroup(m)) {
 337                 Slice *s = SLICE(u);
 338
 339                 /* If we are managing the root cgroup then this means our root slice covers the whole system, which
 340                  * means the kernel will track CPU/tasks/memory for us anyway, and it is all available in /proc. Let's
 341                  * hence turn accounting on here, so that our APIs to query this data are available. */
 342
 343                 s->cgroup_context.cpu_accounting = true;
 344                 s->cgroup_context.tasks_accounting = true;
 345                 s->cgroup_context.memory_accounting = true;
 346         }
 347
 348         if (MANAGER_IS_SYSTEM(m))
 349                 (void) slice_make_perpetual(m, SPECIAL_SYSTEM_SLICE, NULL);
 350 }
 351
 352 const UnitVTable slice_vtable = {
 353         .object_size = sizeof(Slice),
 354         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 355
 356         .sections =
 357                 "Unit\0"
 358                 "Slice\0"
 359                 "Install\0",
 360         .private_section = "Slice",
 361
 362         .can_transient = true,
 363
 364         .init = slice_init,
 365         .load = slice_load,
 366
 367         .coldplug = slice_coldplug,
 368
 369         .dump = slice_dump,
 370
 371         .start = slice_start,
 372         .stop = slice_stop,
 373
 374         .kill = slice_kill,
 375
 376         .serialize = slice_serialize,
 377         .deserialize_item = slice_deserialize_item,
 378
 379         .active_state = slice_active_state,
 380         .sub_state_to_string = slice_sub_state_to_string,
 381
 382         .bus_vtable = bus_slice_vtable,
 383         .bus_set_property = bus_slice_set_property,
 384         .bus_commit_properties = bus_slice_commit_properties,
 385
 386         .enumerate_perpetual = slice_enumerate_perpetual,
 387
 388         .status_message_formats = {
 389                 .finished_start_job = {
 390                         [JOB_DONE]       = "Created slice %s.",
 391                 },
 392                 .finished_stop_job = {
 393                         [JOB_DONE]       = "Removed slice %s.",
 394                 },
 395         },
 396 };