src/core/scope.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <unistd.h>
  22
  23 #include "alloc-util.h"
  24 #include "dbus-scope.h"
  25 #include "load-dropin.h"
  26 #include "log.h"
  27 #include "scope.h"
  28 #include "special.h"
  29 #include "string-table.h"
  30 #include "string-util.h"
  31 #include "strv.h"
  32 #include "unit-name.h"
  33 #include "unit.h"
  34
  35 static const UnitActiveState state_translation_table[_SCOPE_STATE_MAX] = {
  36         [SCOPE_DEAD] = UNIT_INACTIVE,
  37         [SCOPE_RUNNING] = UNIT_ACTIVE,
  38         [SCOPE_ABANDONED] = UNIT_ACTIVE,
  39         [SCOPE_STOP_SIGTERM] = UNIT_DEACTIVATING,
  40         [SCOPE_STOP_SIGKILL] = UNIT_DEACTIVATING,
  41         [SCOPE_FAILED] = UNIT_FAILED
  42 };
  43
  44 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata);
  45
  46 static void scope_init(Unit *u) {
  47         Scope *s = SCOPE(u);
  48
  49         assert(u);
  50         assert(u->load_state == UNIT_STUB);
  51
  52         s->timeout_stop_usec = u->manager->default_timeout_stop_usec;
  53         u->ignore_on_isolate = true;
  54 }
  55
  56 static void scope_done(Unit *u) {
  57         Scope *s = SCOPE(u);
  58
  59         assert(u);
  60
  61         free(s->controller);
  62
  63         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  64 }
  65
  66 static int scope_arm_timer(Scope *s, usec_t usec) {
  67         int r;
  68
  69         assert(s);
  70
  71         if (s->timer_event_source) {
  72                 r = sd_event_source_set_time(s->timer_event_source, usec);
  73                 if (r < 0)
  74                         return r;
  75
  76                 return sd_event_source_set_enabled(s->timer_event_source, SD_EVENT_ONESHOT);
  77         }
  78
  79         if (usec == USEC_INFINITY)
  80                 return 0;
  81
  82         r = sd_event_add_time(
  83                         UNIT(s)->manager->event,
  84                         &s->timer_event_source,
  85                         CLOCK_MONOTONIC,
  86                         usec, 0,
  87                         scope_dispatch_timer, s);
  88         if (r < 0)
  89                 return r;
  90
  91         (void) sd_event_source_set_description(s->timer_event_source, "scope-timer");
  92
  93         return 0;
  94 }
  95
  96 static void scope_set_state(Scope *s, ScopeState state) {
  97         ScopeState old_state;
  98         assert(s);
  99
 100         old_state = s->state;
 101         s->state = state;
 102
 103         if (!IN_SET(state, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 104                 s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 105
 106         if (IN_SET(state, SCOPE_DEAD, SCOPE_FAILED))
 107                 unit_unwatch_all_pids(UNIT(s));
 108
 109         if (state != old_state)
 110                 log_debug("%s changed %s -> %s", UNIT(s)->id, scope_state_to_string(old_state), scope_state_to_string(state));
 111
 112         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
 113 }
 114
 115 static int scope_add_default_dependencies(Scope *s) {
 116         int r;
 117
 118         assert(s);
 119
 120         if (!UNIT(s)->default_dependencies)
 121                 return 0;
 122
 123         /* Make sure scopes are unloaded on shutdown */
 124         r = unit_add_two_dependencies_by_name(
 125                         UNIT(s),
 126                         UNIT_BEFORE, UNIT_CONFLICTS,
 127                         SPECIAL_SHUTDOWN_TARGET, NULL, true);
 128         if (r < 0)
 129                 return r;
 130
 131         return 0;
 132 }
 133
 134 static int scope_verify(Scope *s) {
 135         assert(s);
 136
 137         if (UNIT(s)->load_state != UNIT_LOADED)
 138                 return 0;
 139
 140         if (set_isempty(UNIT(s)->pids) &&
 141             !MANAGER_IS_RELOADING(UNIT(s)->manager) &&
 142             !unit_has_name(UNIT(s), SPECIAL_INIT_SCOPE)) {
 143                 log_unit_error(UNIT(s), "Scope has no PIDs. Refusing.");
 144                 return -EINVAL;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int scope_load_init_scope(Unit *u) {
 151         assert(u);
 152
 153         if (!unit_has_name(u, SPECIAL_INIT_SCOPE))
 154                 return 0;
 155
 156         u->transient = true;
 157         u->perpetual = true;
 158
 159         /* init.scope is a bit special, as it has to stick around forever. Because of its special semantics we
 160          * synthesize it here, instead of relying on the unit file on disk. */
 161
 162         u->default_dependencies = false;
 163         u->ignore_on_isolate = true;
 164
 165         SCOPE(u)->kill_context.kill_signal = SIGRTMIN+14;
 166
 167         /* Prettify things, if we can. */
 168         if (!u->description)
 169                 u->description = strdup("System and Service Manager");
 170         if (!u->documentation)
 171                 (void) strv_extend(&u->documentation, "man:systemd(1)");
 172
 173         return 1;
 174 }
 175
 176 static int scope_load(Unit *u) {
 177         Scope *s = SCOPE(u);
 178         int r;
 179
 180         assert(s);
 181         assert(u->load_state == UNIT_STUB);
 182
 183         if (!u->transient && !MANAGER_IS_RELOADING(u->manager))
 184                 /* Refuse to load non-transient scope units, but allow them while reloading. */
 185                 return -ENOENT;
 186
 187         r = scope_load_init_scope(u);
 188         if (r < 0)
 189                 return r;
 190         r = unit_load_fragment_and_dropin_optional(u);
 191         if (r < 0)
 192                 return r;
 193
 194         if (u->load_state == UNIT_LOADED) {
 195                 r = unit_patch_contexts(u);
 196                 if (r < 0)
 197                         return r;
 198
 199                 r = unit_set_default_slice(u);
 200                 if (r < 0)
 201                         return r;
 202
 203                 r = scope_add_default_dependencies(s);
 204                 if (r < 0)
 205                         return r;
 206         }
 207
 208         return scope_verify(s);
 209 }
 210
 211 static int scope_coldplug(Unit *u) {
 212         Scope *s = SCOPE(u);
 213         int r;
 214
 215         assert(s);
 216         assert(s->state == SCOPE_DEAD);
 217
 218         if (s->deserialized_state == s->state)
 219                 return 0;
 220
 221         if (IN_SET(s->deserialized_state, SCOPE_STOP_SIGKILL, SCOPE_STOP_SIGTERM)) {
 222                 r = scope_arm_timer(s, usec_add(u->state_change_timestamp.monotonic, s->timeout_stop_usec));
 223                 if (r < 0)
 224                         return r;
 225         }
 226
 227         if (!IN_SET(s->deserialized_state, SCOPE_DEAD, SCOPE_FAILED))
 228                 unit_watch_all_pids(UNIT(s));
 229
 230         scope_set_state(s, s->deserialized_state);
 231         return 0;
 232 }
 233
 234 static void scope_dump(Unit *u, FILE *f, const char *prefix) {
 235         Scope *s = SCOPE(u);
 236
 237         assert(s);
 238         assert(f);
 239
 240         fprintf(f,
 241                 "%sScope State: %s\n"
 242                 "%sResult: %s\n",
 243                 prefix, scope_state_to_string(s->state),
 244                 prefix, scope_result_to_string(s->result));
 245
 246         cgroup_context_dump(&s->cgroup_context, f, prefix);
 247         kill_context_dump(&s->kill_context, f, prefix);
 248 }
 249
 250 static void scope_enter_dead(Scope *s, ScopeResult f) {
 251         assert(s);
 252
 253         if (s->result == SCOPE_SUCCESS)
 254                 s->result = f;
 255
 256         if (s->result != SCOPE_SUCCESS)
 257                 log_unit_warning(UNIT(s), "Failed with result '%s'.", scope_result_to_string(s->result));
 258
 259         scope_set_state(s, s->result != SCOPE_SUCCESS ? SCOPE_FAILED : SCOPE_DEAD);
 260 }
 261
 262 static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {
 263         bool skip_signal = false;
 264         int r;
 265
 266         assert(s);
 267
 268         if (s->result == SCOPE_SUCCESS)
 269                 s->result = f;
 270
 271         unit_watch_all_pids(UNIT(s));
 272
 273         /* If we have a controller set let's ask the controller nicely
 274          * to terminate the scope, instead of us going directly into
 275          * SIGTERM berserk mode */
 276         if (state == SCOPE_STOP_SIGTERM)
 277                 skip_signal = bus_scope_send_request_stop(s) > 0;
 278
 279         if (skip_signal)
 280                 r = 1; /* wait */
 281         else {
 282                 r = unit_kill_context(
 283                                 UNIT(s),
 284                                 &s->kill_context,
 285                                 state != SCOPE_STOP_SIGTERM ? KILL_KILL :
 286                                 s->was_abandoned            ? KILL_TERMINATE_AND_LOG :
 287                                                               KILL_TERMINATE,
 288                                 -1, -1, false);
 289                 if (r < 0)
 290                         goto fail;
 291         }
 292
 293         if (r > 0) {
 294                 r = scope_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_stop_usec));
 295                 if (r < 0)
 296                         goto fail;
 297
 298                 scope_set_state(s, state);
 299         } else if (state == SCOPE_STOP_SIGTERM)
 300                 scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_SUCCESS);
 301         else
 302                 scope_enter_dead(s, SCOPE_SUCCESS);
 303
 304         return;
 305
 306 fail:
 307         log_unit_warning_errno(UNIT(s), r, "Failed to kill processes: %m");
 308
 309         scope_enter_dead(s, SCOPE_FAILURE_RESOURCES);
 310 }
 311
 312 static int scope_start(Unit *u) {
 313         Scope *s = SCOPE(u);
 314         int r;
 315
 316         assert(s);
 317
 318         if (unit_has_name(u, SPECIAL_INIT_SCOPE))
 319                 return -EPERM;
 320
 321         if (s->state == SCOPE_FAILED)
 322                 return -EPERM;
 323
 324         /* We can't fulfill this right now, please try again later */
 325         if (IN_SET(s->state, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 326                 return -EAGAIN;
 327
 328         assert(s->state == SCOPE_DEAD);
 329
 330         if (!u->transient && !MANAGER_IS_RELOADING(u->manager))
 331                 return -ENOENT;
 332
 333         r = unit_acquire_invocation_id(u);
 334         if (r < 0)
 335                 return r;
 336
 337         (void) unit_realize_cgroup(u);
 338         (void) unit_reset_cpu_accounting(u);
 339         (void) unit_reset_ip_accounting(u);
 340
 341         r = unit_attach_pids_to_cgroup(u);
 342         if (r < 0) {
 343                 log_unit_warning_errno(UNIT(s), r, "Failed to add PIDs to scope's control group: %m");
 344                 scope_enter_dead(s, SCOPE_FAILURE_RESOURCES);
 345                 return r;
 346         }
 347
 348         s->result = SCOPE_SUCCESS;
 349
 350         scope_set_state(s, SCOPE_RUNNING);
 351         return 1;
 352 }
 353
 354 static int scope_stop(Unit *u) {
 355         Scope *s = SCOPE(u);
 356
 357         assert(s);
 358
 359         if (IN_SET(s->state, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 360                 return 0;
 361
 362         assert(IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED));
 363
 364         scope_enter_signal(s, SCOPE_STOP_SIGTERM, SCOPE_SUCCESS);
 365         return 1;
 366 }
 367
 368 static void scope_reset_failed(Unit *u) {
 369         Scope *s = SCOPE(u);
 370
 371         assert(s);
 372
 373         if (s->state == SCOPE_FAILED)
 374                 scope_set_state(s, SCOPE_DEAD);
 375
 376         s->result = SCOPE_SUCCESS;
 377 }
 378
 379 static int scope_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 380         return unit_kill_common(u, who, signo, -1, -1, error);
 381 }
 382
 383 static int scope_get_timeout(Unit *u, usec_t *timeout) {
 384         Scope *s = SCOPE(u);
 385         usec_t t;
 386         int r;
 387
 388         if (!s->timer_event_source)
 389                 return 0;
 390
 391         r = sd_event_source_get_time(s->timer_event_source, &t);
 392         if (r < 0)
 393                 return r;
 394         if (t == USEC_INFINITY)
 395                 return 0;
 396
 397         *timeout = t;
 398         return 1;
 399 }
 400
 401 static int scope_serialize(Unit *u, FILE *f, FDSet *fds) {
 402         Scope *s = SCOPE(u);
 403
 404         assert(s);
 405         assert(f);
 406         assert(fds);
 407
 408         unit_serialize_item(u, f, "state", scope_state_to_string(s->state));
 409         unit_serialize_item(u, f, "was-abandoned", yes_no(s->was_abandoned));
 410         return 0;
 411 }
 412
 413 static int scope_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 414         Scope *s = SCOPE(u);
 415
 416         assert(u);
 417         assert(key);
 418         assert(value);
 419         assert(fds);
 420
 421         if (streq(key, "state")) {
 422                 ScopeState state;
 423
 424                 state = scope_state_from_string(value);
 425                 if (state < 0)
 426                         log_unit_debug(u, "Failed to parse state value: %s", value);
 427                 else
 428                         s->deserialized_state = state;
 429
 430         } else if (streq(key, "was-abandoned")) {
 431                 int k;
 432
 433                 k = parse_boolean(value);
 434                 if (k < 0)
 435                         log_unit_debug(u, "Failed to parse boolean value: %s", value);
 436                 else
 437                         s->was_abandoned = k;
 438         } else
 439                 log_unit_debug(u, "Unknown serialization key: %s", key);
 440
 441         return 0;
 442 }
 443
 444 static bool scope_check_gc(Unit *u) {
 445         assert(u);
 446
 447         /* Never clean up scopes that still have a process around,
 448          * even if the scope is formally dead. */
 449
 450         if (!u->cgroup_path)
 451                 return false;
 452
 453         return cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path) <= 0;
 454 }
 455
 456 static void scope_notify_cgroup_empty_event(Unit *u) {
 457         Scope *s = SCOPE(u);
 458         assert(u);
 459
 460         log_unit_debug(u, "cgroup is empty");
 461
 462         if (IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 463                 scope_enter_dead(s, SCOPE_SUCCESS);
 464 }
 465
 466 static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 467
 468         /* If we get a SIGCHLD event for one of the processes we were
 469            interested in, then we look for others to watch, under the
 470            assumption that we'll sooner or later get a SIGCHLD for
 471            them, as the original process we watched was probably the
 472            parent of them, and they are hence now our children. */
 473
 474         unit_tidy_watch_pids(u, 0, 0);
 475         unit_watch_all_pids(u);
 476
 477         /* If the PID set is empty now, then let's finish this off
 478            (On unified we use proper notifications) */
 479         if (cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER) == 0 && set_isempty(u->pids))
 480                 scope_notify_cgroup_empty_event(u);
 481 }
 482
 483 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
 484         Scope *s = SCOPE(userdata);
 485
 486         assert(s);
 487         assert(s->timer_event_source == source);
 488
 489         switch (s->state) {
 490
 491         case SCOPE_STOP_SIGTERM:
 492                 if (s->kill_context.send_sigkill) {
 493                         log_unit_warning(UNIT(s), "Stopping timed out. Killing.");
 494                         scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_FAILURE_TIMEOUT);
 495                 } else {
 496                         log_unit_warning(UNIT(s), "Stopping timed out. Skipping SIGKILL.");
 497                         scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 498                 }
 499
 500                 break;
 501
 502         case SCOPE_STOP_SIGKILL:
 503                 log_unit_warning(UNIT(s), "Still around after SIGKILL. Ignoring.");
 504                 scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 505                 break;
 506
 507         default:
 508                 assert_not_reached("Timeout at wrong time.");
 509         }
 510
 511         return 0;
 512 }
 513
 514 int scope_abandon(Scope *s) {
 515         assert(s);
 516
 517         if (unit_has_name(UNIT(s), SPECIAL_INIT_SCOPE))
 518                 return -EPERM;
 519
 520         if (!IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED))
 521                 return -ESTALE;
 522
 523         s->was_abandoned = true;
 524         s->controller = mfree(s->controller);
 525
 526         /* The client is no longer watching the remaining processes,
 527          * so let's step in here, under the assumption that the
 528          * remaining processes will be sooner or later reassigned to
 529          * us as parent. */
 530
 531         unit_tidy_watch_pids(UNIT(s), 0, 0);
 532         unit_watch_all_pids(UNIT(s));
 533
 534         /* If the PID set is empty now, then let's finish this off */
 535         if (set_isempty(UNIT(s)->pids))
 536                 scope_notify_cgroup_empty_event(UNIT(s));
 537         else
 538                 scope_set_state(s, SCOPE_ABANDONED);
 539
 540         return 0;
 541 }
 542
 543 _pure_ static UnitActiveState scope_active_state(Unit *u) {
 544         assert(u);
 545
 546         return state_translation_table[SCOPE(u)->state];
 547 }
 548
 549 _pure_ static const char *scope_sub_state_to_string(Unit *u) {
 550         assert(u);
 551
 552         return scope_state_to_string(SCOPE(u)->state);
 553 }
 554
 555 static void scope_enumerate(Manager *m) {
 556         Unit *u;
 557         int r;
 558
 559         assert(m);
 560
 561         /* Let's unconditionally add the "init.scope" special unit
 562          * that encapsulates PID 1. Note that PID 1 already is in the
 563          * cgroup for this, we hence just need to allocate the object
 564          * for it and that's it. */
 565
 566         u = manager_get_unit(m, SPECIAL_INIT_SCOPE);
 567         if (!u) {
 568                 r = unit_new_for_name(m, sizeof(Scope), SPECIAL_INIT_SCOPE, &u);
 569                 if (r < 0)  {
 570                         log_error_errno(r, "Failed to allocate the special " SPECIAL_INIT_SCOPE " unit: %m");
 571                         return;
 572                 }
 573         }
 574
 575         u->transient = true;
 576         u->perpetual = true;
 577         SCOPE(u)->deserialized_state = SCOPE_RUNNING;
 578
 579         unit_add_to_load_queue(u);
 580         unit_add_to_dbus_queue(u);
 581 }
 582
 583 static const char* const scope_result_table[_SCOPE_RESULT_MAX] = {
 584         [SCOPE_SUCCESS] = "success",
 585         [SCOPE_FAILURE_RESOURCES] = "resources",
 586         [SCOPE_FAILURE_TIMEOUT] = "timeout",
 587 };
 588
 589 DEFINE_STRING_TABLE_LOOKUP(scope_result, ScopeResult);
 590
 591 const UnitVTable scope_vtable = {
 592         .object_size = sizeof(Scope),
 593         .cgroup_context_offset = offsetof(Scope, cgroup_context),
 594         .kill_context_offset = offsetof(Scope, kill_context),
 595
 596         .sections =
 597                 "Unit\0"
 598                 "Scope\0"
 599                 "Install\0",
 600         .private_section = "Scope",
 601
 602         .can_transient = true,
 603
 604         .init = scope_init,
 605         .load = scope_load,
 606         .done = scope_done,
 607
 608         .coldplug = scope_coldplug,
 609
 610         .dump = scope_dump,
 611
 612         .start = scope_start,
 613         .stop = scope_stop,
 614
 615         .kill = scope_kill,
 616
 617         .get_timeout = scope_get_timeout,
 618
 619         .serialize = scope_serialize,
 620         .deserialize_item = scope_deserialize_item,
 621
 622         .active_state = scope_active_state,
 623         .sub_state_to_string = scope_sub_state_to_string,
 624
 625         .check_gc = scope_check_gc,
 626
 627         .sigchld_event = scope_sigchld_event,
 628
 629         .reset_failed = scope_reset_failed,
 630
 631         .notify_cgroup_empty = scope_notify_cgroup_empty_event,
 632
 633         .bus_vtable = bus_scope_vtable,
 634         .bus_set_property = bus_scope_set_property,
 635         .bus_commit_properties = bus_scope_commit_properties,
 636
 637         .enumerate = scope_enumerate,
 638 };