src/core/scope.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25
  26 #include "unit.h"
  27 #include "scope.h"
  28 #include "load-fragment.h"
  29 #include "log.h"
  30 #include "dbus-scope.h"
  31 #include "special.h"
  32 #include "unit-name.h"
  33 #include "load-dropin.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
  54         UNIT(s)->ignore_on_isolate = true;
  55         UNIT(s)->ignore_on_snapshot = true;
  56 }
  57
  58 static void scope_done(Unit *u) {
  59         Scope *s = SCOPE(u);
  60
  61         assert(u);
  62
  63         free(s->controller);
  64
  65         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  66 }
  67
  68 static int scope_arm_timer(Scope *s) {
  69         int r;
  70
  71         assert(s);
  72
  73         if (s->timeout_stop_usec <= 0) {
  74                 s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  75                 return 0;
  76         }
  77
  78         if (s->timer_event_source) {
  79                 r = sd_event_source_set_time(s->timer_event_source, now(CLOCK_MONOTONIC) + s->timeout_stop_usec);
  80                 if (r < 0)
  81                         return r;
  82
  83                 return sd_event_source_set_enabled(s->timer_event_source, SD_EVENT_ONESHOT);
  84         }
  85
  86         return sd_event_add_time(
  87                         UNIT(s)->manager->event,
  88                         &s->timer_event_source,
  89                         CLOCK_MONOTONIC,
  90                         now(CLOCK_MONOTONIC) + s->timeout_stop_usec, 0,
  91                         scope_dispatch_timer, s);
  92 }
  93
  94 static void scope_set_state(Scope *s, ScopeState state) {
  95         ScopeState old_state;
  96         assert(s);
  97
  98         old_state = s->state;
  99         s->state = state;
 100
 101         if (!IN_SET(state, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 102                 s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 103
 104         if (IN_SET(state, SCOPE_DEAD, SCOPE_FAILED))
 105                 unit_unwatch_all_pids(UNIT(s));
 106
 107         if (state != old_state)
 108                 log_debug("%s changed %s -> %s", UNIT(s)->id, scope_state_to_string(old_state), scope_state_to_string(state));
 109
 110         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
 111 }
 112
 113 static int scope_add_default_dependencies(Scope *s) {
 114         int r;
 115
 116         assert(s);
 117
 118         /* Make sure scopes are unloaded on shutdown */
 119         r = unit_add_two_dependencies_by_name(
 120                         UNIT(s),
 121                         UNIT_BEFORE, UNIT_CONFLICTS,
 122                         SPECIAL_SHUTDOWN_TARGET, NULL, true);
 123         if (r < 0)
 124                 return r;
 125
 126         return 0;
 127 }
 128
 129 static int scope_verify(Scope *s) {
 130         assert(s);
 131
 132         if (UNIT(s)->load_state != UNIT_LOADED)
 133                 return 0;
 134
 135         if (set_isempty(UNIT(s)->pids) && UNIT(s)->manager->n_reloading <= 0) {
 136                 log_unit_error(UNIT(s)->id, "Scope %s has no PIDs. Refusing.", UNIT(s)->id);
 137                 return -EINVAL;
 138         }
 139
 140         return 0;
 141 }
 142
 143 static int scope_load(Unit *u) {
 144         Scope *s = SCOPE(u);
 145         int r;
 146
 147         assert(s);
 148         assert(u->load_state == UNIT_STUB);
 149
 150         if (!u->transient && UNIT(s)->manager->n_reloading <= 0)
 151                 return -ENOENT;
 152
 153         u->load_state = UNIT_LOADED;
 154
 155         r = unit_load_dropin(u);
 156         if (r < 0)
 157                 return r;
 158
 159         r = unit_patch_contexts(u);
 160         if (r < 0)
 161                 return r;
 162
 163         r = unit_add_default_slice(u, &s->cgroup_context);
 164         if (r < 0)
 165                 return r;
 166
 167         if (u->default_dependencies) {
 168                 r = scope_add_default_dependencies(s);
 169                 if (r < 0)
 170                         return r;
 171         }
 172
 173         return scope_verify(s);
 174 }
 175
 176 static int scope_coldplug(Unit *u) {
 177         Scope *s = SCOPE(u);
 178         int r;
 179
 180         assert(s);
 181         assert(s->state == SCOPE_DEAD);
 182
 183         if (s->deserialized_state != s->state) {
 184
 185                 if (IN_SET(s->deserialized_state, SCOPE_STOP_SIGKILL, SCOPE_STOP_SIGTERM)) {
 186                         r = scope_arm_timer(s);
 187                         if (r < 0)
 188                                 return r;
 189                 }
 190
 191                 if (!IN_SET(s->deserialized_state, SCOPE_DEAD, SCOPE_FAILED))
 192                         unit_watch_all_pids(UNIT(s));
 193
 194                 scope_set_state(s, s->deserialized_state);
 195         }
 196
 197         return 0;
 198 }
 199
 200 static void scope_dump(Unit *u, FILE *f, const char *prefix) {
 201         Scope *s = SCOPE(u);
 202
 203         assert(s);
 204         assert(f);
 205
 206         fprintf(f,
 207                 "%sScope State: %s\n"
 208                 "%sResult: %s\n",
 209                 prefix, scope_state_to_string(s->state),
 210                 prefix, scope_result_to_string(s->result));
 211
 212         cgroup_context_dump(&s->cgroup_context, f, prefix);
 213         kill_context_dump(&s->kill_context, f, prefix);
 214 }
 215
 216 static void scope_enter_dead(Scope *s, ScopeResult f) {
 217         assert(s);
 218
 219         if (f != SCOPE_SUCCESS)
 220                 s->result = f;
 221
 222         scope_set_state(s, s->result != SCOPE_SUCCESS ? SCOPE_FAILED : SCOPE_DEAD);
 223 }
 224
 225 static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {
 226         bool skip_signal = false;
 227         int r;
 228
 229         assert(s);
 230
 231         if (f != SCOPE_SUCCESS)
 232                 s->result = f;
 233
 234         unit_watch_all_pids(UNIT(s));
 235
 236         /* If we have a controller set let's ask the controller nicely
 237          * to terminate the scope, instead of us going directly into
 238          * SIGTERM beserk mode */
 239         if (state == SCOPE_STOP_SIGTERM)
 240                 skip_signal = bus_scope_send_request_stop(s) > 0;
 241
 242         if (!skip_signal) {
 243                 r = unit_kill_context(
 244                                 UNIT(s),
 245                                 &s->kill_context,
 246                                 state != SCOPE_STOP_SIGTERM ? KILL_KILL : KILL_TERMINATE,
 247                                 -1, -1, false);
 248                 if (r < 0)
 249                         goto fail;
 250         } else
 251                 r = 1;
 252
 253         if (r > 0) {
 254                 r = scope_arm_timer(s);
 255                 if (r < 0)
 256                         goto fail;
 257
 258                 scope_set_state(s, state);
 259         } else if (state == SCOPE_STOP_SIGTERM)
 260                 scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_SUCCESS);
 261         else
 262                 scope_enter_dead(s, SCOPE_SUCCESS);
 263
 264         return;
 265
 266 fail:
 267         log_unit_warning(UNIT(s)->id,
 268                          "%s failed to kill processes: %s", UNIT(s)->id, strerror(-r));
 269
 270         scope_enter_dead(s, SCOPE_FAILURE_RESOURCES);
 271 }
 272
 273 static int scope_start(Unit *u) {
 274         Scope *s = SCOPE(u);
 275         int r;
 276
 277         assert(s);
 278
 279         if (s->state == SCOPE_FAILED)
 280                 return -EPERM;
 281
 282         if (s->state == SCOPE_STOP_SIGTERM ||
 283             s->state == SCOPE_STOP_SIGKILL)
 284                 return -EAGAIN;
 285
 286         assert(s->state == SCOPE_DEAD);
 287
 288         if (!u->transient && UNIT(s)->manager->n_reloading <= 0)
 289                 return -ENOENT;
 290
 291         r = unit_attach_pids_to_cgroup(u);
 292         if (r < 0)
 293                 return r;
 294
 295         s->result = SCOPE_SUCCESS;
 296
 297         scope_set_state(s, SCOPE_RUNNING);
 298         return 1;
 299 }
 300
 301 static int scope_stop(Unit *u) {
 302         Scope *s = SCOPE(u);
 303
 304         assert(s);
 305
 306         if (s->state == SCOPE_STOP_SIGTERM ||
 307             s->state == SCOPE_STOP_SIGKILL)
 308                 return 0;
 309
 310         assert(s->state == SCOPE_RUNNING ||
 311                s->state == SCOPE_ABANDONED);
 312
 313         scope_enter_signal(s, SCOPE_STOP_SIGTERM, SCOPE_SUCCESS);
 314         return 1;
 315 }
 316
 317 static void scope_reset_failed(Unit *u) {
 318         Scope *s = SCOPE(u);
 319
 320         assert(s);
 321
 322         if (s->state == SCOPE_FAILED)
 323                 scope_set_state(s, SCOPE_DEAD);
 324
 325         s->result = SCOPE_SUCCESS;
 326 }
 327
 328 static int scope_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 329         return unit_kill_common(u, who, signo, -1, -1, error);
 330 }
 331
 332 static int scope_get_timeout(Unit *u, uint64_t *timeout) {
 333         Scope *s = SCOPE(u);
 334         int r;
 335
 336         if (!s->timer_event_source)
 337                 return 0;
 338
 339         r = sd_event_source_get_time(s->timer_event_source, timeout);
 340         if (r < 0)
 341                 return r;
 342
 343         return 1;
 344 }
 345
 346 static int scope_serialize(Unit *u, FILE *f, FDSet *fds) {
 347         Scope *s = SCOPE(u);
 348
 349         assert(s);
 350         assert(f);
 351         assert(fds);
 352
 353         unit_serialize_item(u, f, "state", scope_state_to_string(s->state));
 354         return 0;
 355 }
 356
 357 static int scope_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 358         Scope *s = SCOPE(u);
 359
 360         assert(u);
 361         assert(key);
 362         assert(value);
 363         assert(fds);
 364
 365         if (streq(key, "state")) {
 366                 ScopeState state;
 367
 368                 state = scope_state_from_string(value);
 369                 if (state < 0)
 370                         log_debug("Failed to parse state value %s", value);
 371                 else
 372                         s->deserialized_state = state;
 373
 374         } else
 375                 log_debug("Unknown serialization key '%s'", key);
 376
 377         return 0;
 378 }
 379
 380 static bool scope_check_gc(Unit *u) {
 381         assert(u);
 382
 383         /* Never clean up scopes that still have a process around,
 384          * even if the scope is formally dead. */
 385
 386         if (u->cgroup_path) {
 387                 int r;
 388
 389                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);
 390                 if (r <= 0)
 391                         return true;
 392         }
 393
 394         return false;
 395 }
 396
 397 static void scope_notify_cgroup_empty_event(Unit *u) {
 398         Scope *s = SCOPE(u);
 399         assert(u);
 400
 401         log_unit_debug(u->id, "%s: cgroup is empty", u->id);
 402
 403         if (IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 404                 scope_enter_dead(s, SCOPE_SUCCESS);
 405 }
 406
 407 static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 408
 409         /* If we get a SIGCHLD event for one of the processes we were
 410            interested in, then we look for others to watch, under the
 411            assumption that we'll sooner or later get a SIGCHLD for
 412            them, as the original process we watched was probably the
 413            parent of them, and they are hence now our children. */
 414
 415         unit_tidy_watch_pids(u, 0, 0);
 416         unit_watch_all_pids(u);
 417
 418         /* If the PID set is empty now, then let's finish this off */
 419         if (set_isempty(u->pids))
 420                 scope_notify_cgroup_empty_event(u);
 421 }
 422
 423 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
 424         Scope *s = SCOPE(userdata);
 425
 426         assert(s);
 427         assert(s->timer_event_source == source);
 428
 429         switch (s->state) {
 430
 431         case SCOPE_STOP_SIGTERM:
 432                 if (s->kill_context.send_sigkill) {
 433                         log_unit_warning(UNIT(s)->id, "%s stopping timed out. Killing.", UNIT(s)->id);
 434                         scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_FAILURE_TIMEOUT);
 435                 } else {
 436                         log_unit_warning(UNIT(s)->id, "%s stopping timed out. Skipping SIGKILL.", UNIT(s)->id);
 437                         scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 438                 }
 439
 440                 break;
 441
 442         case SCOPE_STOP_SIGKILL:
 443                 log_unit_warning(UNIT(s)->id, "%s still around after SIGKILL. Ignoring.", UNIT(s)->id);
 444                 scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 445                 break;
 446
 447         default:
 448                 assert_not_reached("Timeout at wrong time.");
 449         }
 450
 451         return 0;
 452 }
 453
 454 int scope_abandon(Scope *s) {
 455         assert(s);
 456
 457         if (!IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED))
 458                 return -ESTALE;
 459
 460         free(s->controller);
 461         s->controller = NULL;
 462
 463         /* The client is no longer watching the remaining processes,
 464          * so let's step in here, under the assumption that the
 465          * remaining processes will be sooner or later reassigned to
 466          * us as parent. */
 467
 468         unit_tidy_watch_pids(UNIT(s), 0, 0);
 469         unit_watch_all_pids(UNIT(s));
 470
 471         /* If the PID set is empty now, then let's finish this off */
 472         if (set_isempty(UNIT(s)->pids))
 473                 scope_notify_cgroup_empty_event(UNIT(s));
 474         else
 475                 scope_set_state(s, SCOPE_ABANDONED);
 476
 477         return 0;
 478 }
 479
 480 _pure_ static UnitActiveState scope_active_state(Unit *u) {
 481         assert(u);
 482
 483         return state_translation_table[SCOPE(u)->state];
 484 }
 485
 486 _pure_ static const char *scope_sub_state_to_string(Unit *u) {
 487         assert(u);
 488
 489         return scope_state_to_string(SCOPE(u)->state);
 490 }
 491
 492 static const char* const scope_state_table[_SCOPE_STATE_MAX] = {
 493         [SCOPE_DEAD] = "dead",
 494         [SCOPE_RUNNING] = "running",
 495         [SCOPE_ABANDONED] = "abandoned",
 496         [SCOPE_STOP_SIGTERM] = "stop-sigterm",
 497         [SCOPE_STOP_SIGKILL] = "stop-sigkill",
 498         [SCOPE_FAILED] = "failed",
 499 };
 500
 501 DEFINE_STRING_TABLE_LOOKUP(scope_state, ScopeState);
 502
 503 static const char* const scope_result_table[_SCOPE_RESULT_MAX] = {
 504         [SCOPE_SUCCESS] = "success",
 505         [SCOPE_FAILURE_RESOURCES] = "resources",
 506         [SCOPE_FAILURE_TIMEOUT] = "timeout",
 507 };
 508
 509 DEFINE_STRING_TABLE_LOOKUP(scope_result, ScopeResult);
 510
 511 const UnitVTable scope_vtable = {
 512         .object_size = sizeof(Scope),
 513         .cgroup_context_offset = offsetof(Scope, cgroup_context),
 514         .kill_context_offset = offsetof(Scope, kill_context),
 515
 516         .sections =
 517                 "Unit\0"
 518                 "Scope\0"
 519                 "Install\0",
 520         .private_section = "Scope",
 521
 522         .no_alias = true,
 523         .no_instances = true,
 524
 525         .init = scope_init,
 526         .load = scope_load,
 527         .done = scope_done,
 528
 529         .coldplug = scope_coldplug,
 530
 531         .dump = scope_dump,
 532
 533         .start = scope_start,
 534         .stop = scope_stop,
 535
 536         .kill = scope_kill,
 537
 538         .get_timeout = scope_get_timeout,
 539
 540         .serialize = scope_serialize,
 541         .deserialize_item = scope_deserialize_item,
 542
 543         .active_state = scope_active_state,
 544         .sub_state_to_string = scope_sub_state_to_string,
 545
 546         .check_gc = scope_check_gc,
 547
 548         .sigchld_event = scope_sigchld_event,
 549
 550         .reset_failed = scope_reset_failed,
 551
 552         .notify_cgroup_empty = scope_notify_cgroup_empty_event,
 553
 554         .bus_interface = "org.freedesktop.systemd1.Scope",
 555         .bus_vtable = bus_scope_vtable,
 556         .bus_set_property = bus_scope_set_property,
 557         .bus_commit_properties = bus_scope_commit_properties,
 558
 559         .can_transient = true
 560 };