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 "slice.h"
   9 #include "special.h"
  10 #include "string-util.h"
  11 #include "strv.h"
  12 #include "unit-name.h"
  13 #include "unit.h"
  14
  15 static const UnitActiveState state_translation_table[_SLICE_STATE_MAX] = {
  16         [SLICE_DEAD] = UNIT_INACTIVE,
  17         [SLICE_ACTIVE] = UNIT_ACTIVE
  18 };
  19
  20 static void slice_init(Unit *u) {
  21         assert(u);
  22         assert(u->load_state == UNIT_STUB);
  23
  24         u->ignore_on_isolate = true;
  25 }
  26
  27 static void slice_set_state(Slice *t, SliceState state) {
  28         SliceState old_state;
  29         assert(t);
  30
  31         old_state = t->state;
  32         t->state = state;
  33
  34         if (state != old_state)
  35                 log_debug("%s changed %s -> %s",
  36                           UNIT(t)->id,
  37                           slice_state_to_string(old_state),
  38                           slice_state_to_string(state));
  39
  40         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
  41 }
  42
  43 static int slice_add_parent_slice(Slice *s) {
  44         Unit *u = UNIT(s), *parent;
  45         _cleanup_free_ char *a = NULL;
  46         int r;
  47
  48         assert(s);
  49
  50         if (UNIT_ISSET(u->slice))
  51                 return 0;
  52
  53         r = slice_build_parent_slice(u->id, &a);
  54         if (r <= 0) /* 0 means root slice */
  55                 return r;
  56
  57         r = manager_load_unit(u->manager, a, NULL, NULL, &parent);
  58         if (r < 0)
  59                 return r;
  60
  61         unit_ref_set(&u->slice, u, parent);
  62         return 0;
  63 }
  64
  65 static int slice_add_default_dependencies(Slice *s) {
  66         int r;
  67
  68         assert(s);
  69
  70         if (!UNIT(s)->default_dependencies)
  71                 return 0;
  72
  73         /* Make sure slices are unloaded on shutdown */
  74         r = unit_add_two_dependencies_by_name(
  75                         UNIT(s),
  76                         UNIT_BEFORE, UNIT_CONFLICTS,
  77                         SPECIAL_SHUTDOWN_TARGET, NULL, true, UNIT_DEPENDENCY_DEFAULT);
  78         if (r < 0)
  79                 return r;
  80
  81         return 0;
  82 }
  83
  84 static int slice_verify(Slice *s) {
  85         _cleanup_free_ char *parent = NULL;
  86         int r;
  87
  88         assert(s);
  89
  90         if (UNIT(s)->load_state != UNIT_LOADED)
  91                 return 0;
  92
  93         if (!slice_name_is_valid(UNIT(s)->id)) {
  94                 log_unit_error(UNIT(s), "Slice name %s is not valid. Refusing.", UNIT(s)->id);
  95                 return -ENOEXEC;
  96         }
  97
  98         r = slice_build_parent_slice(UNIT(s)->id, &parent);
  99         if (r < 0)
 100                 return log_unit_error_errno(UNIT(s), r, "Failed to determine parent slice: %m");
 101
 102         if (parent ? !unit_has_name(UNIT_DEREF(UNIT(s)->slice), parent) : UNIT_ISSET(UNIT(s)->slice)) {
 103                 log_unit_error(UNIT(s), "Located outside of parent slice. Refusing.");
 104                 return -ENOEXEC;
 105         }
 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)", NULL);
 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)", NULL);
 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_optional(u);
 169         if (r < 0)
 170                 return r;
 171
 172         /* This is a new unit? Then let's add in some extras */
 173         if (u->load_state == UNIT_LOADED) {
 174
 175                 r = unit_patch_contexts(u);
 176                 if (r < 0)
 177                         return r;
 178
 179                 r = slice_add_parent_slice(s);
 180                 if (r < 0)
 181                         return r;
 182
 183                 r = slice_add_default_dependencies(s);
 184                 if (r < 0)
 185                         return r;
 186         }
 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(&t->cgroup_context, 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_cpu_accounting(u);
 229         (void) unit_reset_ip_accounting(u);
 230
 231         slice_set_state(t, SLICE_ACTIVE);
 232         return 1;
 233 }
 234
 235 static int slice_stop(Unit *u) {
 236         Slice *t = SLICE(u);
 237
 238         assert(t);
 239         assert(t->state == SLICE_ACTIVE);
 240
 241         /* We do not need to destroy the cgroup explicitly,
 242          * unit_notify() will do that for us anyway. */
 243
 244         slice_set_state(t, SLICE_DEAD);
 245         return 1;
 246 }
 247
 248 static int slice_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 249         return unit_kill_common(u, who, signo, -1, -1, error);
 250 }
 251
 252 static int slice_serialize(Unit *u, FILE *f, FDSet *fds) {
 253         Slice *s = SLICE(u);
 254
 255         assert(s);
 256         assert(f);
 257         assert(fds);
 258
 259         unit_serialize_item(u, f, "state", slice_state_to_string(s->state));
 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_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 const UnitVTable slice_vtable = {
 348         .object_size = sizeof(Slice),
 349         .cgroup_context_offset = offsetof(Slice, cgroup_context),
 350
 351         .sections =
 352                 "Unit\0"
 353                 "Slice\0"
 354                 "Install\0",
 355         .private_section = "Slice",
 356
 357         .can_transient = true,
 358
 359         .init = slice_init,
 360         .load = slice_load,
 361
 362         .coldplug = slice_coldplug,
 363
 364         .dump = slice_dump,
 365
 366         .start = slice_start,
 367         .stop = slice_stop,
 368
 369         .kill = slice_kill,
 370
 371         .serialize = slice_serialize,
 372         .deserialize_item = slice_deserialize_item,
 373
 374         .active_state = slice_active_state,
 375         .sub_state_to_string = slice_sub_state_to_string,
 376
 377         .bus_vtable = bus_slice_vtable,
 378         .bus_set_property = bus_slice_set_property,
 379         .bus_commit_properties = bus_slice_commit_properties,
 380
 381         .enumerate_perpetual = slice_enumerate_perpetual,
 382
 383         .status_message_formats = {
 384                 .finished_start_job = {
 385                         [JOB_DONE]       = "Created slice %s.",
 386                 },
 387                 .finished_stop_job = {
 388                         [JOB_DONE]       = "Removed slice %s.",
 389                 },
 390         },
 391 };