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(Unit *u) {
 151         Scope *s = SCOPE(u);
 152         int r;
 153
 154         assert(s);
 155         assert(u->load_state == UNIT_STUB);
 156
 157         if (!u->transient && !MANAGER_IS_RELOADING(u->manager))
 158                 /* Refuse to load non-transient scope units, but allow them while reloading. */
 159                 return -ENOENT;
 160
 161         r = unit_load_fragment_and_dropin_optional(u);
 162         if (r < 0)
 163                 return r;
 164
 165         if (u->load_state == UNIT_LOADED) {
 166                 r = unit_patch_contexts(u);
 167                 if (r < 0)
 168                         return r;
 169
 170                 r = unit_set_default_slice(u);
 171                 if (r < 0)
 172                         return r;
 173
 174                 r = scope_add_default_dependencies(s);
 175                 if (r < 0)
 176                         return r;
 177         }
 178
 179         return scope_verify(s);
 180 }
 181
 182 static int scope_coldplug(Unit *u) {
 183         Scope *s = SCOPE(u);
 184         int r;
 185
 186         assert(s);
 187         assert(s->state == SCOPE_DEAD);
 188
 189         if (s->deserialized_state == s->state)
 190                 return 0;
 191
 192         if (IN_SET(s->deserialized_state, SCOPE_STOP_SIGKILL, SCOPE_STOP_SIGTERM)) {
 193                 r = scope_arm_timer(s, usec_add(u->state_change_timestamp.monotonic, s->timeout_stop_usec));
 194                 if (r < 0)
 195                         return r;
 196         }
 197
 198         if (!IN_SET(s->deserialized_state, SCOPE_DEAD, SCOPE_FAILED))
 199                 unit_watch_all_pids(UNIT(s));
 200
 201         scope_set_state(s, s->deserialized_state);
 202         return 0;
 203 }
 204
 205 static void scope_dump(Unit *u, FILE *f, const char *prefix) {
 206         Scope *s = SCOPE(u);
 207
 208         assert(s);
 209         assert(f);
 210
 211         fprintf(f,
 212                 "%sScope State: %s\n"
 213                 "%sResult: %s\n",
 214                 prefix, scope_state_to_string(s->state),
 215                 prefix, scope_result_to_string(s->result));
 216
 217         cgroup_context_dump(&s->cgroup_context, f, prefix);
 218         kill_context_dump(&s->kill_context, f, prefix);
 219 }
 220
 221 static void scope_enter_dead(Scope *s, ScopeResult f) {
 222         assert(s);
 223
 224         if (f != SCOPE_SUCCESS)
 225                 s->result = f;
 226
 227         scope_set_state(s, s->result != SCOPE_SUCCESS ? SCOPE_FAILED : SCOPE_DEAD);
 228 }
 229
 230 static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {
 231         bool skip_signal = false;
 232         int r;
 233
 234         assert(s);
 235
 236         if (f != SCOPE_SUCCESS)
 237                 s->result = f;
 238
 239         unit_watch_all_pids(UNIT(s));
 240
 241         /* If we have a controller set let's ask the controller nicely
 242          * to terminate the scope, instead of us going directly into
 243          * SIGTERM beserk mode */
 244         if (state == SCOPE_STOP_SIGTERM)
 245                 skip_signal = bus_scope_send_request_stop(s) > 0;
 246
 247         if (!skip_signal) {
 248                 r = unit_kill_context(
 249                                 UNIT(s),
 250                                 &s->kill_context,
 251                                 state != SCOPE_STOP_SIGTERM ? KILL_KILL : KILL_TERMINATE,
 252                                 -1, -1, false);
 253                 if (r < 0)
 254                         goto fail;
 255         } else
 256                 r = 1;
 257
 258         if (r > 0) {
 259                 r = scope_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_stop_usec));
 260                 if (r < 0)
 261                         goto fail;
 262
 263                 scope_set_state(s, state);
 264         } else if (state == SCOPE_STOP_SIGTERM)
 265                 scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_SUCCESS);
 266         else
 267                 scope_enter_dead(s, SCOPE_SUCCESS);
 268
 269         return;
 270
 271 fail:
 272         log_unit_warning_errno(UNIT(s), r, "Failed to kill processes: %m");
 273
 274         scope_enter_dead(s, SCOPE_FAILURE_RESOURCES);
 275 }
 276
 277 static int scope_start(Unit *u) {
 278         Scope *s = SCOPE(u);
 279         int r;
 280
 281         assert(s);
 282
 283         if (unit_has_name(u, SPECIAL_INIT_SCOPE))
 284                 return -EPERM;
 285
 286         if (s->state == SCOPE_FAILED)
 287                 return -EPERM;
 288
 289         /* We can't fulfill this right now, please try again later */
 290         if (s->state == SCOPE_STOP_SIGTERM ||
 291             s->state == SCOPE_STOP_SIGKILL)
 292                 return -EAGAIN;
 293
 294         assert(s->state == SCOPE_DEAD);
 295
 296         if (!u->transient && !MANAGER_IS_RELOADING(u->manager))
 297                 return -ENOENT;
 298
 299         (void) unit_realize_cgroup(u);
 300         (void) unit_reset_cpu_usage(u);
 301
 302         r = unit_attach_pids_to_cgroup(u);
 303         if (r < 0) {
 304                 log_unit_warning_errno(UNIT(s), r, "Failed to add PIDs to scope's control group: %m");
 305                 scope_enter_dead(s, SCOPE_FAILURE_RESOURCES);
 306                 return r;
 307         }
 308
 309         s->result = SCOPE_SUCCESS;
 310
 311         scope_set_state(s, SCOPE_RUNNING);
 312         return 1;
 313 }
 314
 315 static int scope_stop(Unit *u) {
 316         Scope *s = SCOPE(u);
 317
 318         assert(s);
 319
 320         if (s->state == SCOPE_STOP_SIGTERM ||
 321             s->state == SCOPE_STOP_SIGKILL)
 322                 return 0;
 323
 324         assert(s->state == SCOPE_RUNNING ||
 325                s->state == SCOPE_ABANDONED);
 326
 327         scope_enter_signal(s, SCOPE_STOP_SIGTERM, SCOPE_SUCCESS);
 328         return 1;
 329 }
 330
 331 static void scope_reset_failed(Unit *u) {
 332         Scope *s = SCOPE(u);
 333
 334         assert(s);
 335
 336         if (s->state == SCOPE_FAILED)
 337                 scope_set_state(s, SCOPE_DEAD);
 338
 339         s->result = SCOPE_SUCCESS;
 340 }
 341
 342 static int scope_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 343         return unit_kill_common(u, who, signo, -1, -1, error);
 344 }
 345
 346 static int scope_get_timeout(Unit *u, usec_t *timeout) {
 347         Scope *s = SCOPE(u);
 348         usec_t t;
 349         int r;
 350
 351         if (!s->timer_event_source)
 352                 return 0;
 353
 354         r = sd_event_source_get_time(s->timer_event_source, &t);
 355         if (r < 0)
 356                 return r;
 357         if (t == USEC_INFINITY)
 358                 return 0;
 359
 360         *timeout = t;
 361         return 1;
 362 }
 363
 364 static int scope_serialize(Unit *u, FILE *f, FDSet *fds) {
 365         Scope *s = SCOPE(u);
 366
 367         assert(s);
 368         assert(f);
 369         assert(fds);
 370
 371         unit_serialize_item(u, f, "state", scope_state_to_string(s->state));
 372         return 0;
 373 }
 374
 375 static int scope_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 376         Scope *s = SCOPE(u);
 377
 378         assert(u);
 379         assert(key);
 380         assert(value);
 381         assert(fds);
 382
 383         if (streq(key, "state")) {
 384                 ScopeState state;
 385
 386                 state = scope_state_from_string(value);
 387                 if (state < 0)
 388                         log_unit_debug(u, "Failed to parse state value: %s", value);
 389                 else
 390                         s->deserialized_state = state;
 391
 392         } else
 393                 log_unit_debug(u, "Unknown serialization key: %s", key);
 394
 395         return 0;
 396 }
 397
 398 static bool scope_check_gc(Unit *u) {
 399         assert(u);
 400
 401         /* Never clean up scopes that still have a process around,
 402          * even if the scope is formally dead. */
 403
 404         if (!u->cgroup_path)
 405                 return false;
 406
 407         return cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path) <= 0;
 408 }
 409
 410 static void scope_notify_cgroup_empty_event(Unit *u) {
 411         Scope *s = SCOPE(u);
 412         assert(u);
 413
 414         log_unit_debug(u, "cgroup is empty");
 415
 416         if (IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 417                 scope_enter_dead(s, SCOPE_SUCCESS);
 418 }
 419
 420 static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 421
 422         /* If we get a SIGCHLD event for one of the processes we were
 423            interested in, then we look for others to watch, under the
 424            assumption that we'll sooner or later get a SIGCHLD for
 425            them, as the original process we watched was probably the
 426            parent of them, and they are hence now our children. */
 427
 428         unit_tidy_watch_pids(u, 0, 0);
 429         unit_watch_all_pids(u);
 430
 431         /* If the PID set is empty now, then let's finish this off
 432            (On unified we use proper notifications) */
 433         if (cg_unified() <= 0 && set_isempty(u->pids))
 434                 scope_notify_cgroup_empty_event(u);
 435 }
 436
 437 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
 438         Scope *s = SCOPE(userdata);
 439
 440         assert(s);
 441         assert(s->timer_event_source == source);
 442
 443         switch (s->state) {
 444
 445         case SCOPE_STOP_SIGTERM:
 446                 if (s->kill_context.send_sigkill) {
 447                         log_unit_warning(UNIT(s), "Stopping timed out. Killing.");
 448                         scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_FAILURE_TIMEOUT);
 449                 } else {
 450                         log_unit_warning(UNIT(s), "Stopping timed out. Skipping SIGKILL.");
 451                         scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 452                 }
 453
 454                 break;
 455
 456         case SCOPE_STOP_SIGKILL:
 457                 log_unit_warning(UNIT(s), "Still around after SIGKILL. Ignoring.");
 458                 scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 459                 break;
 460
 461         default:
 462                 assert_not_reached("Timeout at wrong time.");
 463         }
 464
 465         return 0;
 466 }
 467
 468 int scope_abandon(Scope *s) {
 469         assert(s);
 470
 471         if (unit_has_name(UNIT(s), SPECIAL_INIT_SCOPE))
 472                 return -EPERM;
 473
 474         if (!IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED))
 475                 return -ESTALE;
 476
 477         s->controller = mfree(s->controller);
 478
 479         /* The client is no longer watching the remaining processes,
 480          * so let's step in here, under the assumption that the
 481          * remaining processes will be sooner or later reassigned to
 482          * us as parent. */
 483
 484         unit_tidy_watch_pids(UNIT(s), 0, 0);
 485         unit_watch_all_pids(UNIT(s));
 486
 487         /* If the PID set is empty now, then let's finish this off */
 488         if (set_isempty(UNIT(s)->pids))
 489                 scope_notify_cgroup_empty_event(UNIT(s));
 490         else
 491                 scope_set_state(s, SCOPE_ABANDONED);
 492
 493         return 0;
 494 }
 495
 496 _pure_ static UnitActiveState scope_active_state(Unit *u) {
 497         assert(u);
 498
 499         return state_translation_table[SCOPE(u)->state];
 500 }
 501
 502 _pure_ static const char *scope_sub_state_to_string(Unit *u) {
 503         assert(u);
 504
 505         return scope_state_to_string(SCOPE(u)->state);
 506 }
 507
 508 static void scope_enumerate(Manager *m) {
 509         Unit *u;
 510         int r;
 511
 512         assert(m);
 513
 514         /* Let's unconditionally add the "init.scope" special unit
 515          * that encapsulates PID 1. Note that PID 1 already is in the
 516          * cgroup for this, we hence just need to allocate the object
 517          * for it and that's it. */
 518
 519         u = manager_get_unit(m, SPECIAL_INIT_SCOPE);
 520         if (!u) {
 521                 u = unit_new(m, sizeof(Scope));
 522                 if (!u) {
 523                         log_oom();
 524                         return;
 525                 }
 526
 527                 r = unit_add_name(u, SPECIAL_INIT_SCOPE);
 528                 if (r < 0)  {
 529                         unit_free(u);
 530                         log_error_errno(r, "Failed to add init.scope name");
 531                         return;
 532                 }
 533         }
 534
 535         u->transient = true;
 536         u->default_dependencies = false;
 537         u->no_gc = true;
 538         u->ignore_on_isolate = true;
 539         u->refuse_manual_start = true;
 540         u->refuse_manual_stop = true;
 541         SCOPE(u)->deserialized_state = SCOPE_RUNNING;
 542         SCOPE(u)->kill_context.kill_signal = SIGRTMIN+14;
 543
 544         /* Prettify things, if we can. */
 545         if (!u->description)
 546                 u->description = strdup("System and Service Manager");
 547         if (!u->documentation)
 548                 (void) strv_extend(&u->documentation, "man:systemd(1)");
 549
 550         unit_add_to_load_queue(u);
 551         unit_add_to_dbus_queue(u);
 552 }
 553
 554 static const char* const scope_result_table[_SCOPE_RESULT_MAX] = {
 555         [SCOPE_SUCCESS] = "success",
 556         [SCOPE_FAILURE_RESOURCES] = "resources",
 557         [SCOPE_FAILURE_TIMEOUT] = "timeout",
 558 };
 559
 560 DEFINE_STRING_TABLE_LOOKUP(scope_result, ScopeResult);
 561
 562 const UnitVTable scope_vtable = {
 563         .object_size = sizeof(Scope),
 564         .cgroup_context_offset = offsetof(Scope, cgroup_context),
 565         .kill_context_offset = offsetof(Scope, kill_context),
 566
 567         .sections =
 568                 "Unit\0"
 569                 "Scope\0"
 570                 "Install\0",
 571         .private_section = "Scope",
 572
 573         .can_transient = true,
 574
 575         .init = scope_init,
 576         .load = scope_load,
 577         .done = scope_done,
 578
 579         .coldplug = scope_coldplug,
 580
 581         .dump = scope_dump,
 582
 583         .start = scope_start,
 584         .stop = scope_stop,
 585
 586         .kill = scope_kill,
 587
 588         .get_timeout = scope_get_timeout,
 589
 590         .serialize = scope_serialize,
 591         .deserialize_item = scope_deserialize_item,
 592
 593         .active_state = scope_active_state,
 594         .sub_state_to_string = scope_sub_state_to_string,
 595
 596         .check_gc = scope_check_gc,
 597
 598         .sigchld_event = scope_sigchld_event,
 599
 600         .reset_failed = scope_reset_failed,
 601
 602         .notify_cgroup_empty = scope_notify_cgroup_empty_event,
 603
 604         .bus_vtable = bus_scope_vtable,
 605         .bus_set_property = bus_scope_set_property,
 606         .bus_commit_properties = bus_scope_commit_properties,
 607
 608         .enumerate = scope_enumerate,
 609 };