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_error_unit(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,
 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_warning_unit(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                 log_error("Failed to realize cgroup: %s", strerror(-r));
 294                 return r;
 295         }
 296
 297         r = cg_attach_many_everywhere(u->manager->cgroup_supported, u->cgroup_path, UNIT(s)->pids);
 298         if (r < 0)
 299                 return r;
 300
 301         s->result = SCOPE_SUCCESS;
 302
 303         scope_set_state(s, SCOPE_RUNNING);
 304         return 0;
 305 }
 306
 307 static int scope_stop(Unit *u) {
 308         Scope *s = SCOPE(u);
 309
 310         assert(s);
 311
 312         if (s->state == SCOPE_STOP_SIGTERM ||
 313             s->state == SCOPE_STOP_SIGKILL)
 314                 return 0;
 315
 316         assert(s->state == SCOPE_RUNNING ||
 317                s->state == SCOPE_ABANDONED);
 318
 319         scope_enter_signal(s, SCOPE_STOP_SIGTERM, SCOPE_SUCCESS);
 320         return 0;
 321 }
 322
 323 static void scope_reset_failed(Unit *u) {
 324         Scope *s = SCOPE(u);
 325
 326         assert(s);
 327
 328         if (s->state == SCOPE_FAILED)
 329                 scope_set_state(s, SCOPE_DEAD);
 330
 331         s->result = SCOPE_SUCCESS;
 332 }
 333
 334 static int scope_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
 335         return unit_kill_common(u, who, signo, -1, -1, error);
 336 }
 337
 338 static int scope_get_timeout(Unit *u, uint64_t *timeout) {
 339         Scope *s = SCOPE(u);
 340         int r;
 341
 342         if (!s->timer_event_source)
 343                 return 0;
 344
 345         r = sd_event_source_get_time(s->timer_event_source, timeout);
 346         if (r < 0)
 347                 return r;
 348
 349         return 1;
 350 }
 351
 352 static int scope_serialize(Unit *u, FILE *f, FDSet *fds) {
 353         Scope *s = SCOPE(u);
 354
 355         assert(s);
 356         assert(f);
 357         assert(fds);
 358
 359         unit_serialize_item(u, f, "state", scope_state_to_string(s->state));
 360         return 0;
 361 }
 362
 363 static int scope_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 364         Scope *s = SCOPE(u);
 365
 366         assert(u);
 367         assert(key);
 368         assert(value);
 369         assert(fds);
 370
 371         if (streq(key, "state")) {
 372                 ScopeState state;
 373
 374                 state = scope_state_from_string(value);
 375                 if (state < 0)
 376                         log_debug("Failed to parse state value %s", value);
 377                 else
 378                         s->deserialized_state = state;
 379
 380         } else
 381                 log_debug("Unknown serialization key '%s'", key);
 382
 383         return 0;
 384 }
 385
 386 static bool scope_check_gc(Unit *u) {
 387         Scope *s = SCOPE(u);
 388         int r;
 389
 390         assert(s);
 391
 392         /* Never clean up scopes that still have a process around,
 393          * even if the scope is formally dead. */
 394
 395         if (u->cgroup_path) {
 396                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);
 397                 if (r <= 0)
 398                         return true;
 399         }
 400
 401         return false;
 402 }
 403
 404 static void scope_notify_cgroup_empty_event(Unit *u) {
 405         Scope *s = SCOPE(u);
 406         assert(u);
 407
 408         log_debug_unit(u->id, "%s: cgroup is empty", u->id);
 409
 410         if (IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED, SCOPE_STOP_SIGTERM, SCOPE_STOP_SIGKILL))
 411                 scope_enter_dead(s, SCOPE_SUCCESS);
 412 }
 413
 414 static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 415
 416         /* If we get a SIGCHLD event for one of the processes we were
 417            interested in, then we look for others to watch, under the
 418            assumption that we'll sooner or later get a SIGCHLD for
 419            them, as the original process we watched was probably the
 420            parent of them, and they are hence now our children. */
 421
 422         unit_tidy_watch_pids(u, 0, 0);
 423         unit_watch_all_pids(u);
 424
 425         /* If the PID set is empty now, then let's finish this off */
 426         if (set_isempty(u->pids))
 427                 scope_notify_cgroup_empty_event(u);
 428 }
 429
 430 static int scope_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
 431         Scope *s = SCOPE(userdata);
 432
 433         assert(s);
 434         assert(s->timer_event_source == source);
 435
 436         switch (s->state) {
 437
 438         case SCOPE_STOP_SIGTERM:
 439                 if (s->kill_context.send_sigkill) {
 440                         log_warning_unit(UNIT(s)->id, "%s stopping timed out. Killing.", UNIT(s)->id);
 441                         scope_enter_signal(s, SCOPE_STOP_SIGKILL, SCOPE_FAILURE_TIMEOUT);
 442                 } else {
 443                         log_warning_unit(UNIT(s)->id, "%s stopping timed out. Skipping SIGKILL.", UNIT(s)->id);
 444                         scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 445                 }
 446
 447                 break;
 448
 449         case SCOPE_STOP_SIGKILL:
 450                 log_warning_unit(UNIT(s)->id, "%s still around after SIGKILL. Ignoring.", UNIT(s)->id);
 451                 scope_enter_dead(s, SCOPE_FAILURE_TIMEOUT);
 452                 break;
 453
 454         default:
 455                 assert_not_reached("Timeout at wrong time.");
 456         }
 457
 458         return 0;
 459 }
 460
 461 int scope_abandon(Scope *s) {
 462         assert(s);
 463
 464         if (!IN_SET(s->state, SCOPE_RUNNING, SCOPE_ABANDONED))
 465                 return -ESTALE;
 466
 467         free(s->controller);
 468         s->controller = NULL;
 469
 470         /* The client is no longer watching the remaining processes,
 471          * so let's step in here, under the assumption that the
 472          * remaining processes will be sooner or later reassigned to
 473          * us as parent. */
 474
 475         unit_tidy_watch_pids(UNIT(s), 0, 0);
 476         unit_watch_all_pids(UNIT(s));
 477
 478         /* If the PID set is empty now, then let's finish this off */
 479         if (set_isempty(UNIT(s)->pids))
 480                 scope_notify_cgroup_empty_event(UNIT(s));
 481         else
 482                 scope_set_state(s, SCOPE_ABANDONED);
 483
 484         return 0;
 485 }
 486
 487 _pure_ static UnitActiveState scope_active_state(Unit *u) {
 488         assert(u);
 489
 490         return state_translation_table[SCOPE(u)->state];
 491 }
 492
 493 _pure_ static const char *scope_sub_state_to_string(Unit *u) {
 494         assert(u);
 495
 496         return scope_state_to_string(SCOPE(u)->state);
 497 }
 498
 499 static const char* const scope_state_table[_SCOPE_STATE_MAX] = {
 500         [SCOPE_DEAD] = "dead",
 501         [SCOPE_RUNNING] = "running",
 502         [SCOPE_ABANDONED] = "abandoned",
 503         [SCOPE_STOP_SIGTERM] = "stop-sigterm",
 504         [SCOPE_STOP_SIGKILL] = "stop-sigkill",
 505         [SCOPE_FAILED] = "failed",
 506 };
 507
 508 DEFINE_STRING_TABLE_LOOKUP(scope_state, ScopeState);
 509
 510 static const char* const scope_result_table[_SCOPE_RESULT_MAX] = {
 511         [SCOPE_SUCCESS] = "success",
 512         [SCOPE_FAILURE_RESOURCES] = "resources",
 513         [SCOPE_FAILURE_TIMEOUT] = "timeout",
 514 };
 515
 516 DEFINE_STRING_TABLE_LOOKUP(scope_result, ScopeResult);
 517
 518 const UnitVTable scope_vtable = {
 519         .object_size = sizeof(Scope),
 520         .cgroup_context_offset = offsetof(Scope, cgroup_context),
 521         .kill_context_offset = offsetof(Scope, kill_context),
 522
 523         .sections =
 524                 "Unit\0"
 525                 "Scope\0"
 526                 "Install\0",
 527         .private_section = "Scope",
 528
 529         .no_alias = true,
 530         .no_instances = true,
 531
 532         .init = scope_init,
 533         .load = scope_load,
 534         .done = scope_done,
 535
 536         .coldplug = scope_coldplug,
 537
 538         .dump = scope_dump,
 539
 540         .start = scope_start,
 541         .stop = scope_stop,
 542
 543         .kill = scope_kill,
 544
 545         .get_timeout = scope_get_timeout,
 546
 547         .serialize = scope_serialize,
 548         .deserialize_item = scope_deserialize_item,
 549
 550         .active_state = scope_active_state,
 551         .sub_state_to_string = scope_sub_state_to_string,
 552
 553         .check_gc = scope_check_gc,
 554
 555         .sigchld_event = scope_sigchld_event,
 556
 557         .reset_failed = scope_reset_failed,
 558
 559         .notify_cgroup_empty = scope_notify_cgroup_empty_event,
 560
 561         .bus_interface = "org.freedesktop.systemd1.Scope",
 562         .bus_vtable = bus_scope_vtable,
 563         .bus_set_property = bus_scope_set_property,
 564         .bus_commit_properties = bus_scope_commit_properties,
 565
 566         .can_transient = true
 567 };