src/logind-session.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/epoll.h>
  26 #include <fcntl.h>
  27
  28 #include "logind-session.h"
  29 #include "strv.h"
  30 #include "util.h"
  31 #include "cgroup-util.h"
  32
  33 #define IDLE_THRESHOLD_USEC (5*USEC_PER_MINUTE)
  34
  35 Session* session_new(Manager *m, User *u, const char *id) {
  36         Session *s;
  37
  38         assert(m);
  39         assert(id);
  40
  41         s = new0(Session, 1);
  42         if (!s)
  43                 return NULL;
  44
  45         s->state_file = strappend("/run/systemd/sessions/", id);
  46         if (!s->state_file) {
  47                 free(s);
  48                 return NULL;
  49         }
  50
  51         s->id = file_name_from_path(s->state_file);
  52
  53         if (hashmap_put(m->sessions, s->id, s) < 0) {
  54                 free(s->id);
  55                 free(s);
  56                 return NULL;
  57         }
  58
  59         s->manager = m;
  60         s->fifo_fd = -1;
  61         s->user = u;
  62
  63         LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
  64
  65         return s;
  66 }
  67
  68 void session_free(Session *s) {
  69         assert(s);
  70
  71         if (s->in_gc_queue)
  72                 LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
  73
  74         if (s->user) {
  75                 LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
  76
  77                 if (s->user->display == s)
  78                         s->user->display = NULL;
  79         }
  80
  81         if (s->seat) {
  82                 if (s->seat->active == s)
  83                         s->seat->active = NULL;
  84
  85                 LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
  86         }
  87
  88         if (s->cgroup_path)
  89                 hashmap_remove(s->manager->cgroups, s->cgroup_path);
  90
  91         free(s->cgroup_path);
  92         strv_free(s->controllers);
  93
  94         free(s->tty);
  95         free(s->display);
  96         free(s->remote_host);
  97         free(s->remote_user);
  98         free(s->service);
  99
 100         hashmap_remove(s->manager->sessions, s->id);
 101
 102         session_remove_fifo(s);
 103
 104         free(s->state_file);
 105         free(s);
 106 }
 107
 108 int session_save(Session *s) {
 109         FILE *f;
 110         int r = 0;
 111         char *temp_path;
 112
 113         assert(s);
 114
 115         if (!s->started)
 116                 return 0;
 117
 118         r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 119         if (r < 0)
 120                 goto finish;
 121
 122         r = fopen_temporary(s->state_file, &f, &temp_path);
 123         if (r < 0)
 124                 goto finish;
 125
 126         assert(s->user);
 127
 128         fchmod(fileno(f), 0644);
 129
 130         fprintf(f,
 131                 "# This is private data. Do not parse.\n"
 132                 "UID=%lu\n"
 133                 "USER=%s\n"
 134                 "ACTIVE=%i\n"
 135                 "REMOTE=%i\n"
 136                 "KILL_PROCESSES=%i\n",
 137                 (unsigned long) s->user->uid,
 138                 s->user->name,
 139                 session_is_active(s),
 140                 s->remote,
 141                 s->kill_processes);
 142
 143         if (s->type >= 0)
 144                 fprintf(f,
 145                         "TYPE=%s\n",
 146                         session_type_to_string(s->type));
 147
 148         if (s->cgroup_path)
 149                 fprintf(f,
 150                         "CGROUP=%s\n",
 151                         s->cgroup_path);
 152
 153         if (s->fifo_path)
 154                 fprintf(f,
 155                         "FIFO=%s\n",
 156                         s->fifo_path);
 157
 158         if (s->seat)
 159                 fprintf(f,
 160                         "SEAT=%s\n",
 161                         s->seat->id);
 162
 163         if (s->tty)
 164                 fprintf(f,
 165                         "TTY=%s\n",
 166                         s->tty);
 167
 168         if (s->display)
 169                 fprintf(f,
 170                         "DISPLAY=%s\n",
 171                         s->display);
 172
 173         if (s->remote_host)
 174                 fprintf(f,
 175                         "REMOTE_HOST=%s\n",
 176                         s->remote_host);
 177
 178         if (s->remote_user)
 179                 fprintf(f,
 180                         "REMOTE_USER=%s\n",
 181                         s->remote_user);
 182
 183         if (s->service)
 184                 fprintf(f,
 185                         "SERVICE=%s\n",
 186                         s->service);
 187
 188         if (s->seat && seat_is_vtconsole(s->seat))
 189                 fprintf(f,
 190                         "VTNR=%i\n",
 191                         s->vtnr);
 192
 193         if (s->leader > 0)
 194                 fprintf(f,
 195                         "LEADER=%lu\n",
 196                         (unsigned long) s->leader);
 197
 198         if (s->audit_id > 0)
 199                 fprintf(f,
 200                         "AUDIT=%llu\n",
 201                         (unsigned long long) s->audit_id);
 202
 203         fflush(f);
 204
 205         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 206                 r = -errno;
 207                 unlink(s->state_file);
 208                 unlink(temp_path);
 209         }
 210
 211         fclose(f);
 212         free(temp_path);
 213
 214 finish:
 215         if (r < 0)
 216                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 217
 218         return r;
 219 }
 220
 221 int session_load(Session *s) {
 222         char *remote = NULL,
 223                 *kill_processes = NULL,
 224                 *seat = NULL,
 225                 *vtnr = NULL,
 226                 *leader = NULL,
 227                 *audit_id = NULL,
 228                 *type = NULL;
 229
 230         int k, r;
 231
 232         assert(s);
 233
 234         r = parse_env_file(s->state_file, NEWLINE,
 235                            "REMOTE",         &remote,
 236                            "KILL_PROCESSES", &kill_processes,
 237                            "CGROUP",         &s->cgroup_path,
 238                            "FIFO",           &s->fifo_path,
 239                            "SEAT",           &seat,
 240                            "TTY",            &s->tty,
 241                            "DISPLAY",        &s->display,
 242                            "REMOTE_HOST",    &s->remote_host,
 243                            "REMOTE_USER",    &s->remote_user,
 244                            "SERVICE",        &s->service,
 245                            "VTNR",           &vtnr,
 246                            "LEADER",         &leader,
 247                            "TYPE",           &type,
 248                            NULL);
 249
 250         if (r < 0)
 251                 goto finish;
 252
 253         if (remote) {
 254                 k = parse_boolean(remote);
 255                 if (k >= 0)
 256                         s->remote = k;
 257         }
 258
 259         if (kill_processes) {
 260                 k = parse_boolean(kill_processes);
 261                 if (k >= 0)
 262                         s->kill_processes = k;
 263         }
 264
 265         if (seat && !s->seat) {
 266                 Seat *o;
 267
 268                 o = hashmap_get(s->manager->seats, seat);
 269                 if (o)
 270                         seat_attach_session(o, s);
 271         }
 272
 273         if (vtnr && s->seat && seat_is_vtconsole(s->seat)) {
 274                 int v;
 275
 276                 k = safe_atoi(vtnr, &v);
 277                 if (k >= 0 && v >= 1)
 278                         s->vtnr = v;
 279         }
 280
 281         if (leader) {
 282                 pid_t pid;
 283
 284                 k = parse_pid(leader, &pid);
 285                 if (k >= 0 && pid >= 1) {
 286                         s->leader = pid;
 287
 288                         audit_session_from_pid(pid, &s->audit_id);
 289                 }
 290         }
 291
 292         if (type) {
 293                 SessionType t;
 294
 295                 t = session_type_from_string(type);
 296                 if (t >= 0)
 297                         s->type = t;
 298         }
 299
 300         session_open_fifo(s);
 301
 302 finish:
 303         free(remote);
 304         free(kill_processes);
 305         free(seat);
 306         free(vtnr);
 307         free(leader);
 308         free(audit_id);
 309
 310         return r;
 311 }
 312
 313 int session_activate(Session *s) {
 314         int r;
 315         Session *old_active;
 316
 317         assert(s);
 318
 319         if (s->vtnr < 0)
 320                 return -ENOTSUP;
 321
 322         if (!s->seat)
 323                 return -ENOTSUP;
 324
 325         if (s->seat->active == s)
 326                 return 0;
 327
 328         assert(seat_is_vtconsole(s->seat));
 329
 330         r = chvt(s->vtnr);
 331         if (r < 0)
 332                 return r;
 333
 334         old_active = s->seat->active;
 335         s->seat->active = s;
 336
 337         return seat_apply_acls(s->seat, old_active);
 338 }
 339
 340 static int session_link_x11_socket(Session *s) {
 341         char *t, *f, *c;
 342         size_t k;
 343
 344         assert(s);
 345         assert(s->user);
 346         assert(s->user->runtime_path);
 347
 348         if (s->user->display)
 349                 return 0;
 350
 351         if (!s->display || !display_is_local(s->display))
 352                 return 0;
 353
 354         k = strspn(s->display+1, "0123456789");
 355         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 356         if (!f) {
 357                 log_error("Out of memory");
 358                 return -ENOMEM;
 359         }
 360
 361         c = stpcpy(f, "/tmp/.X11-unix/X");
 362         memcpy(c, s->display+1, k);
 363         c[k] = 0;
 364
 365         if (access(f, F_OK) < 0) {
 366                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 367                 free(f);
 368                 return -ENOENT;
 369         }
 370
 371         t = strappend(s->user->runtime_path, "/display");
 372         if (!t) {
 373                 log_error("Out of memory");
 374                 free(f);
 375                 return -ENOMEM;
 376         }
 377
 378         if (link(f, t) < 0) {
 379                 if (errno == EEXIST) {
 380                         unlink(t);
 381
 382                         if (link(f, t) >= 0)
 383                                 goto done;
 384                 }
 385
 386                 if (symlink(f, t) < 0) {
 387
 388                         if (errno == EEXIST) {
 389                                 unlink(t);
 390
 391                                 if (symlink(f, t) >= 0)
 392                                         goto done;
 393                         }
 394
 395                         log_error("Failed to link %s to %s: %m", f, t);
 396                         free(f);
 397                         free(t);
 398                         return -errno;
 399                 }
 400         }
 401
 402 done:
 403         log_info("Linked %s to %s.", f, t);
 404         free(f);
 405         free(t);
 406
 407         s->user->display = s;
 408
 409         return 0;
 410 }
 411
 412 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 413         int r;
 414
 415         assert(s);
 416         assert(controller);
 417         assert(path);
 418
 419         if (s->leader > 0) {
 420                 r = cg_create_and_attach(controller, path, s->leader);
 421                 if (r < 0)
 422                         r = cg_create(controller, path);
 423         } else
 424                 r = cg_create(controller, path);
 425
 426         if (r < 0)
 427                 return r;
 428
 429         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid);
 430         if (r >= 0)
 431                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 432
 433         return r;
 434 }
 435
 436 static int session_create_cgroup(Session *s) {
 437         char **k;
 438         char *p;
 439         int r;
 440
 441         assert(s);
 442         assert(s->user);
 443         assert(s->user->cgroup_path);
 444
 445         if (!s->cgroup_path) {
 446                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 447                         log_error("Out of memory");
 448                         return -ENOMEM;
 449                 }
 450         } else
 451                 p = s->cgroup_path;
 452
 453         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 454         if (r < 0) {
 455                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 456                 free(p);
 457                 s->cgroup_path = NULL;
 458                 return r;
 459         }
 460
 461         s->cgroup_path = p;
 462
 463         STRV_FOREACH(k, s->controllers) {
 464
 465                 if (strv_contains(s->reset_controllers, *k))
 466                         continue;
 467
 468                 r = session_create_one_group(s, *k, p);
 469                 if (r < 0)
 470                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 471         }
 472
 473         STRV_FOREACH(k, s->manager->controllers) {
 474
 475                 if (strv_contains(s->reset_controllers, *k) ||
 476                     strv_contains(s->manager->reset_controllers, *k) ||
 477                     strv_contains(s->controllers, *k))
 478                         continue;
 479
 480                 r = session_create_one_group(s, *k, p);
 481                 if (r < 0)
 482                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 483         }
 484
 485         if (s->leader > 0) {
 486
 487                 STRV_FOREACH(k, s->reset_controllers) {
 488                         r = cg_attach(*k, "/", s->leader);
 489                         if (r < 0)
 490                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 491
 492                 }
 493
 494                 STRV_FOREACH(k, s->manager->reset_controllers) {
 495
 496                         if (strv_contains(s->reset_controllers, *k) ||
 497                             strv_contains(s->controllers, *k))
 498                                 continue;
 499
 500                         r = cg_attach(*k, "/", s->leader);
 501                         if (r < 0)
 502                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 503
 504                 }
 505         }
 506
 507         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 508
 509         return 0;
 510 }
 511
 512 int session_start(Session *s) {
 513         int r;
 514
 515         assert(s);
 516         assert(s->user);
 517
 518         if (s->started)
 519                 return 0;
 520
 521         r = user_start(s->user);
 522         if (r < 0)
 523                 return r;
 524
 525         log_info("New session %s of user %s.", s->id, s->user->name);
 526
 527         /* Create cgroup */
 528         r = session_create_cgroup(s);
 529         if (r < 0)
 530                 return r;
 531
 532         /* Create X11 symlink */
 533         session_link_x11_socket(s);
 534
 535         dual_timestamp_get(&s->timestamp);
 536
 537         if (s->seat)
 538                 seat_read_active_vt(s->seat);
 539
 540         s->started = true;
 541
 542         /* Save session data */
 543         session_save(s);
 544         user_save(s->user);
 545
 546         session_send_signal(s, true);
 547
 548         if (s->seat) {
 549                 seat_save(s->seat);
 550
 551                 if (s->seat->active == s)
 552                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 553                 else
 554                         seat_send_changed(s->seat, "Sessions\0");
 555         }
 556
 557         user_send_changed(s->user, "Sessions\0");
 558
 559         return 0;
 560 }
 561
 562 static bool session_shall_kill(Session *s) {
 563         assert(s);
 564
 565         if (!s->kill_processes)
 566                 return false;
 567
 568         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 569                 return false;
 570
 571         if (strv_isempty(s->manager->kill_only_users))
 572                 return true;
 573
 574         return strv_contains(s->manager->kill_only_users, s->user->name);
 575 }
 576
 577 static int session_kill_cgroup(Session *s) {
 578         int r;
 579         char **k;
 580
 581         assert(s);
 582
 583         if (!s->cgroup_path)
 584                 return 0;
 585
 586         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 587
 588         if (session_shall_kill(s)) {
 589
 590                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 591                 if (r < 0)
 592                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 593
 594         } else {
 595                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 596                 if (r < 0)
 597                         log_error("Failed to check session cgroup: %s", strerror(-r));
 598                 else if (r > 0) {
 599                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 600                         if (r < 0)
 601                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 602                 } else
 603                         r = -EBUSY;
 604         }
 605
 606         STRV_FOREACH(k, s->user->manager->controllers)
 607                 cg_trim(*k, s->cgroup_path, true);
 608
 609         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 610
 611         free(s->cgroup_path);
 612         s->cgroup_path = NULL;
 613
 614         return r;
 615 }
 616
 617 static int session_unlink_x11_socket(Session *s) {
 618         char *t;
 619         int r;
 620
 621         assert(s);
 622         assert(s->user);
 623
 624         if (s->user->display != s)
 625                 return 0;
 626
 627         s->user->display = NULL;
 628
 629         t = strappend(s->user->runtime_path, "/display");
 630         if (!t) {
 631                 log_error("Out of memory");
 632                 return -ENOMEM;
 633         }
 634
 635         r = unlink(t);
 636         free(t);
 637
 638         return r < 0 ? -errno : 0;
 639 }
 640
 641 int session_stop(Session *s) {
 642         int r = 0, k;
 643
 644         assert(s);
 645
 646         if (s->started)
 647                 log_info("Removed session %s.", s->id);
 648
 649         /* Kill cgroup */
 650         k = session_kill_cgroup(s);
 651         if (k < 0)
 652                 r = k;
 653
 654         /* Remove X11 symlink */
 655         session_unlink_x11_socket(s);
 656
 657         unlink(s->state_file);
 658         session_add_to_gc_queue(s);
 659         user_add_to_gc_queue(s->user);
 660
 661         if (s->started)
 662                 session_send_signal(s, false);
 663
 664         if (s->seat) {
 665                 if (s->seat->active == s)
 666                         seat_set_active(s->seat, NULL);
 667
 668                 seat_send_changed(s->seat, "Sessions\0");
 669         }
 670
 671         user_send_changed(s->user, "Sessions\0");
 672
 673         s->started = false;
 674
 675         return r;
 676 }
 677
 678 bool session_is_active(Session *s) {
 679         assert(s);
 680
 681         if (!s->seat)
 682                 return true;
 683
 684         return s->seat->active == s;
 685 }
 686
 687 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 688         char *p;
 689         struct stat st;
 690         usec_t u, n;
 691         bool b;
 692         int k;
 693
 694         assert(s);
 695
 696         if (s->idle_hint) {
 697                 if (t)
 698                         *t = s->idle_hint_timestamp;
 699
 700                 return s->idle_hint;
 701         }
 702
 703         if (isempty(s->tty))
 704                 goto dont_know;
 705
 706         if (s->tty[0] != '/') {
 707                 p = strappend("/dev/", s->tty);
 708                 if (!p)
 709                         return -ENOMEM;
 710         } else
 711                 p = NULL;
 712
 713         if (!startswith(p ? p : s->tty, "/dev/")) {
 714                 free(p);
 715                 goto dont_know;
 716         }
 717
 718         k = lstat(p ? p : s->tty, &st);
 719         free(p);
 720
 721         if (k < 0)
 722                 goto dont_know;
 723
 724         u = timespec_load(&st.st_atim);
 725         n = now(CLOCK_REALTIME);
 726         b = u + IDLE_THRESHOLD_USEC < n;
 727
 728         if (t)
 729                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 730
 731         return b;
 732
 733 dont_know:
 734         if (t)
 735                 *t = s->idle_hint_timestamp;
 736
 737         return 0;
 738 }
 739
 740 void session_set_idle_hint(Session *s, bool b) {
 741         assert(s);
 742
 743         if (s->idle_hint == b)
 744                 return;
 745
 746         s->idle_hint = b;
 747         dual_timestamp_get(&s->idle_hint_timestamp);
 748
 749         session_send_changed(s,
 750                              "IdleHint\0"
 751                              "IdleSinceHint\0"
 752                              "IdleSinceHintMonotonic\0");
 753
 754         if (s->seat)
 755                 seat_send_changed(s->seat,
 756                                   "IdleHint\0"
 757                                   "IdleSinceHint\0"
 758                                   "IdleSinceHintMonotonic\0");
 759
 760         user_send_changed(s->user,
 761                           "IdleHint\0"
 762                           "IdleSinceHint\0"
 763                           "IdleSinceHintMonotonic\0");
 764
 765         manager_send_changed(s->manager,
 766                              "IdleHint\0"
 767                              "IdleSinceHint\0"
 768                              "IdleSinceHintMonotonic\0");
 769 }
 770
 771 int session_open_fifo(Session *s) {
 772         struct epoll_event ev;
 773         int r;
 774
 775         assert(s);
 776
 777         if (s->fifo_fd >= 0)
 778                 return 0;
 779
 780         if (!s->fifo_path)
 781                 return -EINVAL;
 782
 783         s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 784         if (s->fifo_fd < 0)
 785                 return -errno;
 786
 787         r = hashmap_put(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1), s);
 788         if (r < 0)
 789                 return r;
 790
 791         zero(ev);
 792         ev.events = 0;
 793         ev.data.u32 = FD_FIFO_BASE + s->fifo_fd;
 794
 795         if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
 796                 return -errno;
 797
 798         return 0;
 799 }
 800
 801 int session_create_fifo(Session *s) {
 802         int r;
 803
 804         assert(s);
 805
 806         if (!s->fifo_path) {
 807                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 808                         return -ENOMEM;
 809
 810                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 811                         return -errno;
 812         }
 813
 814         /* Open reading side */
 815         r = session_open_fifo(s);
 816         if (r < 0)
 817                 return r;
 818
 819         /* Open writing side */
 820         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 821         if (r < 0)
 822                 return -errno;
 823
 824         return r;
 825 }
 826
 827 void session_remove_fifo(Session *s) {
 828         assert(s);
 829
 830         if (s->fifo_fd >= 0) {
 831                 assert_se(hashmap_remove(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
 832                 assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
 833                 close_nointr_nofail(s->fifo_fd);
 834                 s->fifo_fd = -1;
 835         }
 836
 837         if (s->fifo_path) {
 838                 unlink(s->fifo_path);
 839                 free(s->fifo_path);
 840                 s->fifo_path = NULL;
 841         }
 842 }
 843
 844 int session_check_gc(Session *s, bool drop_not_started) {
 845         int r;
 846
 847         assert(s);
 848
 849         if (drop_not_started && !s->started)
 850                 return 0;
 851
 852         if (s->fifo_fd >= 0) {
 853
 854                 r = pipe_eof(s->fifo_fd);
 855                 if (r < 0)
 856                         return r;
 857
 858                 if (r == 0)
 859                         return 1;
 860         }
 861
 862         if (s->cgroup_path) {
 863
 864                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 865                 if (r < 0)
 866                         return r;
 867
 868                 if (r <= 0)
 869                         return 1;
 870         }
 871
 872         return 0;
 873 }
 874
 875 void session_add_to_gc_queue(Session *s) {
 876         assert(s);
 877
 878         if (s->in_gc_queue)
 879                 return;
 880
 881         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 882         s->in_gc_queue = true;
 883 }
 884
 885 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 886         [SESSION_TTY] = "tty",
 887         [SESSION_X11] = "x11",
 888         [SESSION_UNSPECIFIED] = "unspecified"
 889 };
 890
 891 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);