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_realize_cgroup(u);
 292         if (r < 0)
 293                 return log_error_errno(r, "Failed to realize cgroup: %m");
 294
 295         r = cg_attach_many_everywhere(u->manager->cgroup_supported, u->cgroup_path, UNIT(s)->pids);
 296         if (r < 0)
 297                 return r;
 298
 299         s->result = SCOPE_SUCCESS;
 300
 301         scope_set_state(s, SCOPE_RUNNING);
 302         return 0;
 303 }
 304
 305 static int scope_stop(Unit *u) {
 306         Scope *s = SCOPE(u);
 307
 308         assert(s);
 309
 310         if (s->state == SCOPE_STOP_SIGTERM ||
 311             s->state == SCOPE_STOP_SIGKILL)
 312                 return 0;
 313
 314         assert(s->state == SCOPE_RUNNING ||
 315                s->state == SCOPE_ABANDONED);
 316
 317         scope_enter_signal(s, SCOPE_STOP_SIGTERM, SCOPE_SUCCESS);
 318         return 0;
 319 }
 320
 321 static void scope_reset_failed(Unit *u) {
 322         Scope *s = SCOPE(u);
 323
 324         assert(s);
 325
 326         if (s->state == SCOPE_FAILED)
 327                 scope_set_state(s, SCOPE_DEAD);
 328
 329         s->result = SCOPE_SUCCESS;
 330 }
 331
 332 static int scope_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 333         return unit_kill_common(u, who, signo, -1, -1, error);
 334 }
 335
 336 static int scope_get_timeout(Unit *u, uint64_t *timeout) {
 337         Scope *s = SCOPE(u);
 338         int r;
 339
 340         if (!s->timer_event_source)
 341                 return 0;
 342
 343         r = sd_event_source_get_time(s->timer_event_source, timeout);
 344         if (r < 0)
 345                 return r;
 346
 347         return 1;
 348 }
 349
 350 static int scope_serialize(Unit *u, FILE *f, FDSet *fds) {
 351         Scope *s = SCOPE(u);
 352
 353         assert(s);
 354         assert(f);
 355         assert(fds);
 356
 357         unit_serialize_item(u, f, "state", scope_state_to_string(s->state));
 358         return 0;
 359 }
 360
 361 static int scope_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 362         Scope *s = SCOPE(u);
 363
 364         assert(u);
 365         assert(key);
 366         assert(value);
 367         assert(fds);
 368
 369         if (streq(key, "state")) {
 370                 ScopeState state;
 371
 372                 state = scope_state_from_string(value);
 373                 if (state < 0)
 374                         log_debug("Failed to parse state value %s", value);
 375                 else
 376                         s->deserialized_state = state;
 377
 378         } else
 379                 log_debug("Unknown serialization key '%s'", key);
 380
 381         return 0;
 382 }
 383
 384 static bool scope_check_gc(Unit *u) {
 385         assert(u);
 386
 387         /* Never clean up scopes that still have a process around,
 388          * even if the scope is formally dead. */
 389
 390         if (u->cgroup_path) {
 391                 int r;
 392
 393                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);
 394                 if (r <= 0)
 395                         return true;
 396         }
 397
 398         return false;
 399 }
 400
 401 static void scope_notify_cgroup_empty_event(Unit *u) {
 402         Scope *s = SCOPE(u);
 403         assert(u);
 404
 405         log_unit_debug(u->id, "%s: cgroup is empty", u->id);
 406
 407         if (IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 408                 scope_enter_dead(s, SCOPE_SUCCESS);
 409 }
 410
 411 static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 412
 413         /* If we get a SIGCHLD event for one of the processes we were
 414            interested in, then we look for others to watch, under the
 415            assumption that we'll sooner or later get a SIGCHLD for
 416            them, as the original process we watched was probably the
 417            parent of them, and they are hence now our children. */
 418
 419         unit_tidy_watch_pids(u, 0, 0);
 420         unit_watch_all_pids(u);
 421
 422         /* If the PID set is empty now, then let's finish this off */
 423         if (set_isempty(u->pids))
 424                 scope_notify_cgroup_empty_event(u);
 425 }
 426
 427 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
 428         Scope *s = SCOPE(userdata);
 429
 430         assert(s);
 431         assert(s->timer_event_source == source);
 432
 433         switch (s->state) {
 434
 435         case SCOPE_STOP_SIGTERM:
 436                 if (s->kill_context.send_sigkill) {
 437                         log_unit_warning(UNIT(s)->id, "%s stopping timed out. Killing.", UNIT(s)->id);
 438                         scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_FAILURE_TIMEOUT);
 439                 } else {
 440                         log_unit_warning(UNIT(s)->id, "%s stopping timed out. Skipping SIGKILL.", UNIT(s)->id);
 441                         scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 442                 }
 443
 444                 break;
 445
 446         case SCOPE_STOP_SIGKILL:
 447                 log_unit_warning(UNIT(s)->id, "%s still around after SIGKILL. Ignoring.", UNIT(s)->id);
 448                 scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 449                 break;
 450
 451         default:
 452                 assert_not_reached("Timeout at wrong time.");
 453         }
 454
 455         return 0;
 456 }
 457
 458 int scope_abandon(Scope *s) {
 459         assert(s);
 460
 461         if (!IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED))
 462                 return -ESTALE;
 463
 464         free(s->controller);
 465         s->controller = NULL;
 466
 467         /* The client is no longer watching the remaining processes,
 468          * so let's step in here, under the assumption that the
 469          * remaining processes will be sooner or later reassigned to
 470          * us as parent. */
 471
 472         unit_tidy_watch_pids(UNIT(s), 0, 0);
 473         unit_watch_all_pids(UNIT(s));
 474
 475         /* If the PID set is empty now, then let's finish this off */
 476         if (set_isempty(UNIT(s)->pids))
 477                 scope_notify_cgroup_empty_event(UNIT(s));
 478         else
 479                 scope_set_state(s, SCOPE_ABANDONED);
 480
 481         return 0;
 482 }
 483
 484 _pure_ static UnitActiveState scope_active_state(Unit *u) {
 485         assert(u);
 486
 487         return state_translation_table[SCOPE(u)->state];
 488 }
 489
 490 _pure_ static const char *scope_sub_state_to_string(Unit *u) {
 491         assert(u);
 492
 493         return scope_state_to_string(SCOPE(u)->state);
 494 }
 495
 496 static const char* const scope_state_table[_SCOPE_STATE_MAX] = {
 497         [SCOPE_DEAD] = "dead",
 498         [SCOPE_RUNNING] = "running",
 499         [SCOPE_ABANDONED] = "abandoned",
 500         [SCOPE_STOP_SIGTERM] = "stop-sigterm",
 501         [SCOPE_STOP_SIGKILL] = "stop-sigkill",
 502         [SCOPE_FAILED] = "failed",
 503 };
 504
 505 DEFINE_STRING_TABLE_LOOKUP(scope_state, ScopeState);
 506
 507 static const char* const scope_result_table[_SCOPE_RESULT_MAX] = {
 508         [SCOPE_SUCCESS] = "success",
 509         [SCOPE_FAILURE_RESOURCES] = "resources",
 510         [SCOPE_FAILURE_TIMEOUT] = "timeout",
 511 };
 512
 513 DEFINE_STRING_TABLE_LOOKUP(scope_result, ScopeResult);
 514
 515 const UnitVTable scope_vtable = {
 516         .object_size = sizeof(Scope),
 517         .cgroup_context_offset = offsetof(Scope, cgroup_context),
 518         .kill_context_offset = offsetof(Scope, kill_context),
 519
 520         .sections =
 521                 "Unit\0"
 522                 "Scope\0"
 523                 "Install\0",
 524         .private_section = "Scope",
 525
 526         .no_alias = true,
 527         .no_instances = true,
 528
 529         .init = scope_init,
 530         .load = scope_load,
 531         .done = scope_done,
 532
 533         .coldplug = scope_coldplug,
 534
 535         .dump = scope_dump,
 536
 537         .start = scope_start,
 538         .stop = scope_stop,
 539
 540         .kill = scope_kill,
 541
 542         .get_timeout = scope_get_timeout,
 543
 544         .serialize = scope_serialize,
 545         .deserialize_item = scope_deserialize_item,
 546
 547         .active_state = scope_active_state,
 548         .sub_state_to_string = scope_sub_state_to_string,
 549
 550         .check_gc = scope_check_gc,
 551
 552         .sigchld_event = scope_sigchld_event,
 553
 554         .reset_failed = scope_reset_failed,
 555
 556         .notify_cgroup_empty = scope_notify_cgroup_empty_event,
 557
 558         .bus_interface = "org.freedesktop.systemd1.Scope",
 559         .bus_vtable = bus_scope_vtable,
 560         .bus_set_property = bus_scope_set_property,
 561         .bus_commit_properties = bus_scope_commit_properties,
 562
 563         .can_transient = true
 564 };