src/login/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 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 <string.h>
  24 #include <unistd.h>
  25 #include <sys/epoll.h>
  26 #include <fcntl.h>
  27
  28 #include "strv.h"
  29 #include "util.h"
  30 #include "mkdir.h"
  31 #include "cgroup-util.h"
  32 #include "logind-session.h"
  33
  34 #define IDLE_THRESHOLD_USEC (5*USEC_PER_MINUTE)
  35
  36 Session* session_new(Manager *m, User *u, const char *id) {
  37         Session *s;
  38
  39         assert(m);
  40         assert(id);
  41
  42         s = new0(Session, 1);
  43         if (!s)
  44                 return NULL;
  45
  46         s->state_file = strappend("/run/systemd/sessions/", id);
  47         if (!s->state_file) {
  48                 free(s);
  49                 return NULL;
  50         }
  51
  52         s->id = file_name_from_path(s->state_file);
  53
  54         if (hashmap_put(m->sessions, s->id, s) < 0) {
  55                 free(s->state_file);
  56                 free(s);
  57                 return NULL;
  58         }
  59
  60         s->manager = m;
  61         s->fifo_fd = -1;
  62         s->user = u;
  63
  64         LIST_PREPEND(Session, sessions_by_user, u->sessions, s);
  65
  66         return s;
  67 }
  68
  69 void session_free(Session *s) {
  70         assert(s);
  71
  72         if (s->in_gc_queue)
  73                 LIST_REMOVE(Session, gc_queue, s->manager->session_gc_queue, s);
  74
  75         if (s->user) {
  76                 LIST_REMOVE(Session, sessions_by_user, s->user->sessions, s);
  77
  78                 if (s->user->display == s)
  79                         s->user->display = NULL;
  80         }
  81
  82         if (s->seat) {
  83                 if (s->seat->active == s)
  84                         s->seat->active = NULL;
  85
  86                 LIST_REMOVE(Session, sessions_by_seat, s->seat->sessions, s);
  87         }
  88
  89         if (s->cgroup_path)
  90                 hashmap_remove(s->manager->cgroups, s->cgroup_path);
  91
  92         free(s->cgroup_path);
  93         strv_free(s->controllers);
  94
  95         free(s->tty);
  96         free(s->display);
  97         free(s->remote_host);
  98         free(s->remote_user);
  99         free(s->service);
 100
 101         hashmap_remove(s->manager->sessions, s->id);
 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->class >= 0)
 149                 fprintf(f,
 150                         "CLASS=%s\n",
 151                         session_class_to_string(s->class));
 152
 153         if (s->cgroup_path)
 154                 fprintf(f,
 155                         "CGROUP=%s\n",
 156                         s->cgroup_path);
 157
 158         if (s->fifo_path)
 159                 fprintf(f,
 160                         "FIFO=%s\n",
 161                         s->fifo_path);
 162
 163         if (s->seat)
 164                 fprintf(f,
 165                         "SEAT=%s\n",
 166                         s->seat->id);
 167
 168         if (s->tty)
 169                 fprintf(f,
 170                         "TTY=%s\n",
 171                         s->tty);
 172
 173         if (s->display)
 174                 fprintf(f,
 175                         "DISPLAY=%s\n",
 176                         s->display);
 177
 178         if (s->remote_host)
 179                 fprintf(f,
 180                         "REMOTE_HOST=%s\n",
 181                         s->remote_host);
 182
 183         if (s->remote_user)
 184                 fprintf(f,
 185                         "REMOTE_USER=%s\n",
 186                         s->remote_user);
 187
 188         if (s->service)
 189                 fprintf(f,
 190                         "SERVICE=%s\n",
 191                         s->service);
 192
 193         if (s->seat && seat_can_multi_session(s->seat))
 194                 fprintf(f,
 195                         "VTNR=%i\n",
 196                         s->vtnr);
 197
 198         if (s->leader > 0)
 199                 fprintf(f,
 200                         "LEADER=%lu\n",
 201                         (unsigned long) s->leader);
 202
 203         if (s->audit_id > 0)
 204                 fprintf(f,
 205                         "AUDIT=%llu\n",
 206                         (unsigned long long) s->audit_id);
 207
 208         fflush(f);
 209
 210         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 211                 r = -errno;
 212                 unlink(s->state_file);
 213                 unlink(temp_path);
 214         }
 215
 216         fclose(f);
 217         free(temp_path);
 218
 219 finish:
 220         if (r < 0)
 221                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 222
 223         return r;
 224 }
 225
 226 int session_load(Session *s) {
 227         char *remote = NULL,
 228                 *kill_processes = NULL,
 229                 *seat = NULL,
 230                 *vtnr = NULL,
 231                 *leader = NULL,
 232                 *audit_id = NULL,
 233                 *type = NULL,
 234                 *class = NULL;
 235
 236         int k, r;
 237
 238         assert(s);
 239
 240         r = parse_env_file(s->state_file, NEWLINE,
 241                            "REMOTE",         &remote,
 242                            "KILL_PROCESSES", &kill_processes,
 243                            "CGROUP",         &s->cgroup_path,
 244                            "FIFO",           &s->fifo_path,
 245                            "SEAT",           &seat,
 246                            "TTY",            &s->tty,
 247                            "DISPLAY",        &s->display,
 248                            "REMOTE_HOST",    &s->remote_host,
 249                            "REMOTE_USER",    &s->remote_user,
 250                            "SERVICE",        &s->service,
 251                            "VTNR",           &vtnr,
 252                            "LEADER",         &leader,
 253                            "TYPE",           &type,
 254                            "CLASS",          &class,
 255                            NULL);
 256
 257         if (r < 0)
 258                 goto finish;
 259
 260         if (remote) {
 261                 k = parse_boolean(remote);
 262                 if (k >= 0)
 263                         s->remote = k;
 264         }
 265
 266         if (kill_processes) {
 267                 k = parse_boolean(kill_processes);
 268                 if (k >= 0)
 269                         s->kill_processes = k;
 270         }
 271
 272         if (seat && !s->seat) {
 273                 Seat *o;
 274
 275                 o = hashmap_get(s->manager->seats, seat);
 276                 if (o)
 277                         seat_attach_session(o, s);
 278         }
 279
 280         if (vtnr && s->seat && seat_can_multi_session(s->seat)) {
 281                 int v;
 282
 283                 k = safe_atoi(vtnr, &v);
 284                 if (k >= 0 && v >= 1)
 285                         s->vtnr = v;
 286         }
 287
 288         if (leader) {
 289                 k = parse_pid(leader, &s->leader);
 290                 if (k >= 0)
 291                         audit_session_from_pid(s->leader, &s->audit_id);
 292         }
 293
 294         if (type) {
 295                 SessionType t;
 296
 297                 t = session_type_from_string(type);
 298                 if (t >= 0)
 299                         s->type = t;
 300         }
 301
 302         if (class) {
 303                 SessionClass c;
 304
 305                 c = session_class_from_string(class);
 306                 if (c >= 0)
 307                         s->class = c;
 308         }
 309
 310         if (s->fifo_path) {
 311                 int fd;
 312
 313                 /* If we open an unopened pipe for reading we will not
 314                    get an EOF. to trigger an EOF we hence open it for
 315                    reading, but close it right-away which then will
 316                    trigger the EOF. */
 317
 318                 fd = session_create_fifo(s);
 319                 if (fd >= 0)
 320                         close_nointr_nofail(fd);
 321         }
 322
 323 finish:
 324         free(remote);
 325         free(kill_processes);
 326         free(seat);
 327         free(vtnr);
 328         free(leader);
 329         free(audit_id);
 330         free(class);
 331
 332         return r;
 333 }
 334
 335 int session_activate(Session *s) {
 336         int r;
 337
 338         assert(s);
 339
 340         if (s->vtnr < 0)
 341                 return -ENOTSUP;
 342
 343         if (!s->seat)
 344                 return -ENOTSUP;
 345
 346         if (s->seat->active == s)
 347                 return 0;
 348
 349         assert(seat_is_vtconsole(s->seat));
 350
 351         r = chvt(s->vtnr);
 352         if (r < 0)
 353                 return r;
 354
 355         return seat_set_active(s->seat, s);
 356 }
 357
 358 static int session_link_x11_socket(Session *s) {
 359         char *t, *f, *c;
 360         size_t k;
 361
 362         assert(s);
 363         assert(s->user);
 364         assert(s->user->runtime_path);
 365
 366         if (s->user->display)
 367                 return 0;
 368
 369         if (!s->display || !display_is_local(s->display))
 370                 return 0;
 371
 372         k = strspn(s->display+1, "0123456789");
 373         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 374         if (!f) {
 375                 log_error("Out of memory");
 376                 return -ENOMEM;
 377         }
 378
 379         c = stpcpy(f, "/tmp/.X11-unix/X");
 380         memcpy(c, s->display+1, k);
 381         c[k] = 0;
 382
 383         if (access(f, F_OK) < 0) {
 384                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 385                 free(f);
 386                 return -ENOENT;
 387         }
 388
 389         /* Note that this cannot be in a subdir to avoid
 390          * vulnerabilities since we are privileged but the runtime
 391          * path is owned by the user */
 392
 393         t = strappend(s->user->runtime_path, "/X11-display");
 394         if (!t) {
 395                 log_error("Out of memory");
 396                 free(f);
 397                 return -ENOMEM;
 398         }
 399
 400         if (link(f, t) < 0) {
 401                 if (errno == EEXIST) {
 402                         unlink(t);
 403
 404                         if (link(f, t) >= 0)
 405                                 goto done;
 406                 }
 407
 408                 if (symlink(f, t) < 0) {
 409
 410                         if (errno == EEXIST) {
 411                                 unlink(t);
 412
 413                                 if (symlink(f, t) >= 0)
 414                                         goto done;
 415                         }
 416
 417                         log_error("Failed to link %s to %s: %m", f, t);
 418                         free(f);
 419                         free(t);
 420                         return -errno;
 421                 }
 422         }
 423
 424 done:
 425         log_info("Linked %s to %s.", f, t);
 426         free(f);
 427         free(t);
 428
 429         s->user->display = s;
 430
 431         return 0;
 432 }
 433
 434 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 435         int r;
 436
 437         assert(s);
 438         assert(controller);
 439         assert(path);
 440
 441         if (s->leader > 0) {
 442                 r = cg_create_and_attach(controller, path, s->leader);
 443                 if (r < 0)
 444                         r = cg_create(controller, path);
 445         } else
 446                 r = cg_create(controller, path);
 447
 448         if (r < 0)
 449                 return r;
 450
 451         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid, -1);
 452         if (r >= 0)
 453                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 454
 455         return r;
 456 }
 457
 458 static int session_create_cgroup(Session *s) {
 459         char **k;
 460         char *p;
 461         int r;
 462
 463         assert(s);
 464         assert(s->user);
 465         assert(s->user->cgroup_path);
 466
 467         if (!s->cgroup_path) {
 468                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 469                         log_error("Out of memory");
 470                         return -ENOMEM;
 471                 }
 472         } else
 473                 p = s->cgroup_path;
 474
 475         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 476         if (r < 0) {
 477                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 478                 free(p);
 479                 s->cgroup_path = NULL;
 480                 return r;
 481         }
 482
 483         s->cgroup_path = p;
 484
 485         STRV_FOREACH(k, s->controllers) {
 486
 487                 if (strv_contains(s->reset_controllers, *k))
 488                         continue;
 489
 490                 r = session_create_one_group(s, *k, p);
 491                 if (r < 0)
 492                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 493         }
 494
 495         STRV_FOREACH(k, s->manager->controllers) {
 496
 497                 if (strv_contains(s->reset_controllers, *k) ||
 498                     strv_contains(s->manager->reset_controllers, *k) ||
 499                     strv_contains(s->controllers, *k))
 500                         continue;
 501
 502                 r = session_create_one_group(s, *k, p);
 503                 if (r < 0)
 504                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 505         }
 506
 507         if (s->leader > 0) {
 508
 509                 STRV_FOREACH(k, s->reset_controllers) {
 510                         r = cg_attach(*k, "/", s->leader);
 511                         if (r < 0)
 512                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 513
 514                 }
 515
 516                 STRV_FOREACH(k, s->manager->reset_controllers) {
 517
 518                         if (strv_contains(s->reset_controllers, *k) ||
 519                             strv_contains(s->controllers, *k))
 520                                 continue;
 521
 522                         r = cg_attach(*k, "/", s->leader);
 523                         if (r < 0)
 524                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 525
 526                 }
 527         }
 528
 529         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 530
 531         return 0;
 532 }
 533
 534 int session_start(Session *s) {
 535         int r;
 536
 537         assert(s);
 538         assert(s->user);
 539
 540         if (s->started)
 541                 return 0;
 542
 543         r = user_start(s->user);
 544         if (r < 0)
 545                 return r;
 546
 547         log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 548                  "New session %s of user %s.", s->id, s->user->name);
 549
 550         /* Create cgroup */
 551         r = session_create_cgroup(s);
 552         if (r < 0)
 553                 return r;
 554
 555         /* Create X11 symlink */
 556         session_link_x11_socket(s);
 557
 558         dual_timestamp_get(&s->timestamp);
 559
 560         if (s->seat)
 561                 seat_read_active_vt(s->seat);
 562
 563         s->started = true;
 564
 565         /* Save session data */
 566         session_save(s);
 567         user_save(s->user);
 568
 569         session_send_signal(s, true);
 570
 571         if (s->seat) {
 572                 seat_save(s->seat);
 573
 574                 if (s->seat->active == s)
 575                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 576                 else
 577                         seat_send_changed(s->seat, "Sessions\0");
 578         }
 579
 580         user_send_changed(s->user, "Sessions\0");
 581
 582         return 0;
 583 }
 584
 585 static bool session_shall_kill(Session *s) {
 586         assert(s);
 587
 588         if (!s->kill_processes)
 589                 return false;
 590
 591         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 592                 return false;
 593
 594         if (strv_isempty(s->manager->kill_only_users))
 595                 return true;
 596
 597         return strv_contains(s->manager->kill_only_users, s->user->name);
 598 }
 599
 600 static int session_terminate_cgroup(Session *s) {
 601         int r;
 602         char **k;
 603
 604         assert(s);
 605
 606         if (!s->cgroup_path)
 607                 return 0;
 608
 609         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 610
 611         if (session_shall_kill(s)) {
 612
 613                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 614                 if (r < 0)
 615                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 616
 617         } else {
 618                 if (s->leader > 0) {
 619                         Session *t;
 620
 621                         /* We still send a HUP to the leader process,
 622                          * even if we are not supposed to kill the
 623                          * whole cgroup. But let's first check the
 624                          * leader still exists and belongs to our
 625                          * session... */
 626
 627                         r = manager_get_session_by_pid(s->manager, s->leader, &t);
 628                         if (r > 0 && t == s) {
 629                                 kill(s->leader, SIGTERM); /* for normal processes */
 630                                 kill(s->leader, SIGHUP);  /* for shells */
 631                                 kill(s->leader, SIGCONT); /* in case they are stopped */
 632                         }
 633                 }
 634
 635                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 636                 if (r < 0)
 637                         log_error("Failed to check session cgroup: %s", strerror(-r));
 638                 else if (r > 0) {
 639                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 640                         if (r < 0)
 641                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 642                 }
 643         }
 644
 645         STRV_FOREACH(k, s->user->manager->controllers)
 646                 cg_trim(*k, s->cgroup_path, true);
 647
 648         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 649
 650         free(s->cgroup_path);
 651         s->cgroup_path = NULL;
 652
 653         return 0;
 654 }
 655
 656 static int session_unlink_x11_socket(Session *s) {
 657         char *t;
 658         int r;
 659
 660         assert(s);
 661         assert(s->user);
 662
 663         if (s->user->display != s)
 664                 return 0;
 665
 666         s->user->display = NULL;
 667
 668         t = strappend(s->user->runtime_path, "/X11-display");
 669         if (!t) {
 670                 log_error("Out of memory");
 671                 return -ENOMEM;
 672         }
 673
 674         r = unlink(t);
 675         free(t);
 676
 677         return r < 0 ? -errno : 0;
 678 }
 679
 680 int session_stop(Session *s) {
 681         int r = 0, k;
 682
 683         assert(s);
 684
 685         if (s->started)
 686                 log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 687                          "Removed session %s.", s->id);
 688
 689         /* Kill cgroup */
 690         k = session_terminate_cgroup(s);
 691         if (k < 0)
 692                 r = k;
 693
 694         /* Remove X11 symlink */
 695         session_unlink_x11_socket(s);
 696
 697         unlink(s->state_file);
 698         session_add_to_gc_queue(s);
 699         user_add_to_gc_queue(s->user);
 700
 701         if (s->started)
 702                 session_send_signal(s, false);
 703
 704         if (s->seat) {
 705                 if (s->seat->active == s)
 706                         seat_set_active(s->seat, NULL);
 707
 708                 seat_send_changed(s->seat, "Sessions\0");
 709         }
 710
 711         user_send_changed(s->user, "Sessions\0");
 712
 713         s->started = false;
 714
 715         return r;
 716 }
 717
 718 bool session_is_active(Session *s) {
 719         assert(s);
 720
 721         if (!s->seat)
 722                 return true;
 723
 724         return s->seat->active == s;
 725 }
 726
 727 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 728         char *p;
 729         struct stat st;
 730         usec_t u, n;
 731         bool b;
 732         int k;
 733
 734         assert(s);
 735
 736         if (s->idle_hint) {
 737                 if (t)
 738                         *t = s->idle_hint_timestamp;
 739
 740                 return s->idle_hint;
 741         }
 742
 743         if (isempty(s->tty))
 744                 goto dont_know;
 745
 746         if (s->tty[0] != '/') {
 747                 p = strappend("/dev/", s->tty);
 748                 if (!p)
 749                         return -ENOMEM;
 750         } else
 751                 p = NULL;
 752
 753         if (!startswith(p ? p : s->tty, "/dev/")) {
 754                 free(p);
 755                 goto dont_know;
 756         }
 757
 758         k = lstat(p ? p : s->tty, &st);
 759         free(p);
 760
 761         if (k < 0)
 762                 goto dont_know;
 763
 764         u = timespec_load(&st.st_atim);
 765         n = now(CLOCK_REALTIME);
 766         b = u + IDLE_THRESHOLD_USEC < n;
 767
 768         if (t)
 769                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 770
 771         return b;
 772
 773 dont_know:
 774         if (t)
 775                 *t = s->idle_hint_timestamp;
 776
 777         return 0;
 778 }
 779
 780 void session_set_idle_hint(Session *s, bool b) {
 781         assert(s);
 782
 783         if (s->idle_hint == b)
 784                 return;
 785
 786         s->idle_hint = b;
 787         dual_timestamp_get(&s->idle_hint_timestamp);
 788
 789         session_send_changed(s,
 790                              "IdleHint\0"
 791                              "IdleSinceHint\0"
 792                              "IdleSinceHintMonotonic\0");
 793
 794         if (s->seat)
 795                 seat_send_changed(s->seat,
 796                                   "IdleHint\0"
 797                                   "IdleSinceHint\0"
 798                                   "IdleSinceHintMonotonic\0");
 799
 800         user_send_changed(s->user,
 801                           "IdleHint\0"
 802                           "IdleSinceHint\0"
 803                           "IdleSinceHintMonotonic\0");
 804
 805         manager_send_changed(s->manager,
 806                              "IdleHint\0"
 807                              "IdleSinceHint\0"
 808                              "IdleSinceHintMonotonic\0");
 809 }
 810
 811 int session_create_fifo(Session *s) {
 812         int r;
 813
 814         assert(s);
 815
 816         /* Create FIFO */
 817         if (!s->fifo_path) {
 818                 r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 819                 if (r < 0)
 820                         return r;
 821
 822                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 823                         return -ENOMEM;
 824
 825                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 826                         return -errno;
 827         }
 828
 829         /* Open reading side */
 830         if (s->fifo_fd < 0) {
 831                 struct epoll_event ev;
 832
 833                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 834                 if (s->fifo_fd < 0)
 835                         return -errno;
 836
 837                 r = hashmap_put(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1), s);
 838                 if (r < 0)
 839                         return r;
 840
 841                 zero(ev);
 842                 ev.events = 0;
 843                 ev.data.u32 = FD_FIFO_BASE + s->fifo_fd;
 844
 845                 if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
 846                         return -errno;
 847         }
 848
 849         /* Open writing side */
 850         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 851         if (r < 0)
 852                 return -errno;
 853
 854         return r;
 855 }
 856
 857 void session_remove_fifo(Session *s) {
 858         assert(s);
 859
 860         if (s->fifo_fd >= 0) {
 861                 assert_se(hashmap_remove(s->manager->session_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
 862                 assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
 863                 close_nointr_nofail(s->fifo_fd);
 864                 s->fifo_fd = -1;
 865         }
 866
 867         if (s->fifo_path) {
 868                 unlink(s->fifo_path);
 869                 free(s->fifo_path);
 870                 s->fifo_path = NULL;
 871         }
 872 }
 873
 874 int session_check_gc(Session *s, bool drop_not_started) {
 875         int r;
 876
 877         assert(s);
 878
 879         if (drop_not_started && !s->started)
 880                 return 0;
 881
 882         if (s->fifo_fd >= 0) {
 883
 884                 r = pipe_eof(s->fifo_fd);
 885                 if (r < 0)
 886                         return r;
 887
 888                 if (r == 0)
 889                         return 1;
 890         }
 891
 892         if (s->cgroup_path) {
 893
 894                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 895                 if (r < 0)
 896                         return r;
 897
 898                 if (r <= 0)
 899                         return 1;
 900         }
 901
 902         return 0;
 903 }
 904
 905 void session_add_to_gc_queue(Session *s) {
 906         assert(s);
 907
 908         if (s->in_gc_queue)
 909                 return;
 910
 911         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 912         s->in_gc_queue = true;
 913 }
 914
 915 int session_kill(Session *s, KillWho who, int signo) {
 916         int r = 0;
 917         Set *pid_set = NULL;
 918
 919         assert(s);
 920
 921         if (!s->cgroup_path)
 922                 return -ESRCH;
 923
 924         if (s->leader <= 0 && who == KILL_LEADER)
 925                 return -ESRCH;
 926
 927         if (s->leader > 0)
 928                 if (kill(s->leader, signo) < 0)
 929                         r = -errno;
 930
 931         if (who == KILL_ALL) {
 932                 int q;
 933
 934                 pid_set = set_new(trivial_hash_func, trivial_compare_func);
 935                 if (!pid_set)
 936                         return -ENOMEM;
 937
 938                 if (s->leader > 0) {
 939                         q = set_put(pid_set, LONG_TO_PTR(s->leader));
 940                         if (q < 0)
 941                                 r = q;
 942                 }
 943
 944                 q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, signo, false, true, false, pid_set);
 945                 if (q < 0)
 946                         if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
 947                                 r = q;
 948         }
 949
 950         if (pid_set)
 951                 set_free(pid_set);
 952
 953         return r;
 954 }
 955
 956 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 957         [SESSION_TTY] = "tty",
 958         [SESSION_X11] = "x11",
 959         [SESSION_UNSPECIFIED] = "unspecified"
 960 };
 961
 962 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
 963
 964 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
 965         [SESSION_USER] = "user",
 966         [SESSION_GREETER] = "greeter",
 967         [SESSION_LOCK_SCREEN] = "lock-screen"
 968 };
 969
 970 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
 971
 972 static const char* const kill_who_table[_KILL_WHO_MAX] = {
 973         [KILL_LEADER] = "leader",
 974         [KILL_ALL] = "all"
 975 };
 976
 977 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);