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 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->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                 pid_t pid;
 290
 291                 k = parse_pid(leader, &pid);
 292                 if (k >= 0 && pid >= 1) {
 293                         s->leader = pid;
 294
 295                         audit_session_from_pid(pid, &s->audit_id);
 296                 }
 297         }
 298
 299         if (type) {
 300                 SessionType t;
 301
 302                 t = session_type_from_string(type);
 303                 if (t >= 0)
 304                         s->type = t;
 305         }
 306
 307         if (class) {
 308                 SessionClass c;
 309
 310                 c = session_class_from_string(class);
 311                 if (c >= 0)
 312                         s->class = c;
 313         }
 314
 315         if (s->fifo_path) {
 316                 int fd;
 317
 318                 /* If we open an unopened pipe for reading we will not
 319                    get an EOF. to trigger an EOF we hence open it for
 320                    reading, but close it right-away which then will
 321                    trigger the EOF. */
 322
 323                 fd = session_create_fifo(s);
 324                 if (fd >= 0)
 325                         close_nointr_nofail(fd);
 326         }
 327
 328
 329 finish:
 330         free(remote);
 331         free(kill_processes);
 332         free(seat);
 333         free(vtnr);
 334         free(leader);
 335         free(audit_id);
 336
 337         return r;
 338 }
 339
 340 int session_activate(Session *s) {
 341         int r;
 342
 343         assert(s);
 344
 345         if (s->vtnr < 0)
 346                 return -ENOTSUP;
 347
 348         if (!s->seat)
 349                 return -ENOTSUP;
 350
 351         if (s->seat->active == s)
 352                 return 0;
 353
 354         assert(seat_is_vtconsole(s->seat));
 355
 356         r = chvt(s->vtnr);
 357         if (r < 0)
 358                 return r;
 359
 360         return seat_set_active(s->seat, s);
 361 }
 362
 363 static int session_link_x11_socket(Session *s) {
 364         char *t, *f, *c;
 365         size_t k;
 366
 367         assert(s);
 368         assert(s->user);
 369         assert(s->user->runtime_path);
 370
 371         if (s->user->display)
 372                 return 0;
 373
 374         if (!s->display || !display_is_local(s->display))
 375                 return 0;
 376
 377         k = strspn(s->display+1, "0123456789");
 378         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 379         if (!f) {
 380                 log_error("Out of memory");
 381                 return -ENOMEM;
 382         }
 383
 384         c = stpcpy(f, "/tmp/.X11-unix/X");
 385         memcpy(c, s->display+1, k);
 386         c[k] = 0;
 387
 388         if (access(f, F_OK) < 0) {
 389                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 390                 free(f);
 391                 return -ENOENT;
 392         }
 393
 394         t = strappend(s->user->runtime_path, "/X11-display");
 395         if (!t) {
 396                 log_error("Out of memory");
 397                 free(f);
 398                 return -ENOMEM;
 399         }
 400
 401         if (link(f, t) < 0) {
 402                 if (errno == EEXIST) {
 403                         unlink(t);
 404
 405                         if (link(f, t) >= 0)
 406                                 goto done;
 407                 }
 408
 409                 if (symlink(f, t) < 0) {
 410
 411                         if (errno == EEXIST) {
 412                                 unlink(t);
 413
 414                                 if (symlink(f, t) >= 0)
 415                                         goto done;
 416                         }
 417
 418                         log_error("Failed to link %s to %s: %m", f, t);
 419                         free(f);
 420                         free(t);
 421                         return -errno;
 422                 }
 423         }
 424
 425 done:
 426         log_info("Linked %s to %s.", f, t);
 427         free(f);
 428         free(t);
 429
 430         s->user->display = s;
 431
 432         return 0;
 433 }
 434
 435 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 436         int r;
 437
 438         assert(s);
 439         assert(controller);
 440         assert(path);
 441
 442         if (s->leader > 0) {
 443                 r = cg_create_and_attach(controller, path, s->leader);
 444                 if (r < 0)
 445                         r = cg_create(controller, path);
 446         } else
 447                 r = cg_create(controller, path);
 448
 449         if (r < 0)
 450                 return r;
 451
 452         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid, -1);
 453         if (r >= 0)
 454                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 455
 456         return r;
 457 }
 458
 459 static int session_create_cgroup(Session *s) {
 460         char **k;
 461         char *p;
 462         int r;
 463
 464         assert(s);
 465         assert(s->user);
 466         assert(s->user->cgroup_path);
 467
 468         if (!s->cgroup_path) {
 469                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 470                         log_error("Out of memory");
 471                         return -ENOMEM;
 472                 }
 473         } else
 474                 p = s->cgroup_path;
 475
 476         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 477         if (r < 0) {
 478                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 479                 free(p);
 480                 s->cgroup_path = NULL;
 481                 return r;
 482         }
 483
 484         s->cgroup_path = p;
 485
 486         STRV_FOREACH(k, s->controllers) {
 487
 488                 if (strv_contains(s->reset_controllers, *k))
 489                         continue;
 490
 491                 r = session_create_one_group(s, *k, p);
 492                 if (r < 0)
 493                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 494         }
 495
 496         STRV_FOREACH(k, s->manager->controllers) {
 497
 498                 if (strv_contains(s->reset_controllers, *k) ||
 499                     strv_contains(s->manager->reset_controllers, *k) ||
 500                     strv_contains(s->controllers, *k))
 501                         continue;
 502
 503                 r = session_create_one_group(s, *k, p);
 504                 if (r < 0)
 505                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 506         }
 507
 508         if (s->leader > 0) {
 509
 510                 STRV_FOREACH(k, s->reset_controllers) {
 511                         r = cg_attach(*k, "/", s->leader);
 512                         if (r < 0)
 513                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 514
 515                 }
 516
 517                 STRV_FOREACH(k, s->manager->reset_controllers) {
 518
 519                         if (strv_contains(s->reset_controllers, *k) ||
 520                             strv_contains(s->controllers, *k))
 521                                 continue;
 522
 523                         r = cg_attach(*k, "/", s->leader);
 524                         if (r < 0)
 525                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 526
 527                 }
 528         }
 529
 530         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 531
 532         return 0;
 533 }
 534
 535 int session_start(Session *s) {
 536         int r;
 537
 538         assert(s);
 539         assert(s->user);
 540
 541         if (s->started)
 542                 return 0;
 543
 544         r = user_start(s->user);
 545         if (r < 0)
 546                 return r;
 547
 548         log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 549                  "New session %s of user %s.", s->id, s->user->name);
 550
 551         /* Create cgroup */
 552         r = session_create_cgroup(s);
 553         if (r < 0)
 554                 return r;
 555
 556         /* Create X11 symlink */
 557         session_link_x11_socket(s);
 558
 559         dual_timestamp_get(&s->timestamp);
 560
 561         if (s->seat)
 562                 seat_read_active_vt(s->seat);
 563
 564         s->started = true;
 565
 566         /* Save session data */
 567         session_save(s);
 568         user_save(s->user);
 569
 570         session_send_signal(s, true);
 571
 572         if (s->seat) {
 573                 seat_save(s->seat);
 574
 575                 if (s->seat->active == s)
 576                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 577                 else
 578                         seat_send_changed(s->seat, "Sessions\0");
 579         }
 580
 581         user_send_changed(s->user, "Sessions\0");
 582
 583         return 0;
 584 }
 585
 586 static bool session_shall_kill(Session *s) {
 587         assert(s);
 588
 589         if (!s->kill_processes)
 590                 return false;
 591
 592         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 593                 return false;
 594
 595         if (strv_isempty(s->manager->kill_only_users))
 596                 return true;
 597
 598         return strv_contains(s->manager->kill_only_users, s->user->name);
 599 }
 600
 601 static int session_terminate_cgroup(Session *s) {
 602         int r;
 603         char **k;
 604
 605         assert(s);
 606
 607         if (!s->cgroup_path)
 608                 return 0;
 609
 610         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 611
 612         if (session_shall_kill(s)) {
 613
 614                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 615                 if (r < 0)
 616                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 617
 618         } else {
 619                 if (s->leader > 0) {
 620                         Session *t;
 621
 622                         /* We still send a HUP to the leader process,
 623                          * even if we are not supposed to kill the
 624                          * whole cgroup. But let's first check the
 625                          * leader still exists and belongs to our
 626                          * session... */
 627
 628                         r = manager_get_session_by_pid(s->manager, s->leader, &t);
 629                         if (r > 0 && t == s) {
 630                                 kill(s->leader, SIGTERM); /* for normal processes */
 631                                 kill(s->leader, SIGHUP);  /* for shells */
 632                                 kill(s->leader, SIGCONT); /* in case they are stopped */
 633                         }
 634                 }
 635
 636                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 637                 if (r < 0)
 638                         log_error("Failed to check session cgroup: %s", strerror(-r));
 639                 else if (r > 0) {
 640                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 641                         if (r < 0)
 642                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 643                 }
 644         }
 645
 646         STRV_FOREACH(k, s->user->manager->controllers)
 647                 cg_trim(*k, s->cgroup_path, true);
 648
 649         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 650
 651         free(s->cgroup_path);
 652         s->cgroup_path = NULL;
 653
 654         return 0;
 655 }
 656
 657 static int session_unlink_x11_socket(Session *s) {
 658         char *t;
 659         int r;
 660
 661         assert(s);
 662         assert(s->user);
 663
 664         if (s->user->display != s)
 665                 return 0;
 666
 667         s->user->display = NULL;
 668
 669         t = strappend(s->user->runtime_path, "/X11-display");
 670         if (!t) {
 671                 log_error("Out of memory");
 672                 return -ENOMEM;
 673         }
 674
 675         r = unlink(t);
 676         free(t);
 677
 678         return r < 0 ? -errno : 0;
 679 }
 680
 681 int session_stop(Session *s) {
 682         int r = 0, k;
 683
 684         assert(s);
 685
 686         if (s->started)
 687                 log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 688                          "Removed session %s.", s->id);
 689
 690         /* Kill cgroup */
 691         k = session_terminate_cgroup(s);
 692         if (k < 0)
 693                 r = k;
 694
 695         /* Remove X11 symlink */
 696         session_unlink_x11_socket(s);
 697
 698         unlink(s->state_file);
 699         session_add_to_gc_queue(s);
 700         user_add_to_gc_queue(s->user);
 701
 702         if (s->started)
 703                 session_send_signal(s, false);
 704
 705         if (s->seat) {
 706                 if (s->seat->active == s)
 707                         seat_set_active(s->seat, NULL);
 708
 709                 seat_send_changed(s->seat, "Sessions\0");
 710         }
 711
 712         user_send_changed(s->user, "Sessions\0");
 713
 714         s->started = false;
 715
 716         return r;
 717 }
 718
 719 bool session_is_active(Session *s) {
 720         assert(s);
 721
 722         if (!s->seat)
 723                 return true;
 724
 725         return s->seat->active == s;
 726 }
 727
 728 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 729         char *p;
 730         struct stat st;
 731         usec_t u, n;
 732         bool b;
 733         int k;
 734
 735         assert(s);
 736
 737         if (s->idle_hint) {
 738                 if (t)
 739                         *t = s->idle_hint_timestamp;
 740
 741                 return s->idle_hint;
 742         }
 743
 744         if (isempty(s->tty))
 745                 goto dont_know;
 746
 747         if (s->tty[0] != '/') {
 748                 p = strappend("/dev/", s->tty);
 749                 if (!p)
 750                         return -ENOMEM;
 751         } else
 752                 p = NULL;
 753
 754         if (!startswith(p ? p : s->tty, "/dev/")) {
 755                 free(p);
 756                 goto dont_know;
 757         }
 758
 759         k = lstat(p ? p : s->tty, &st);
 760         free(p);
 761
 762         if (k < 0)
 763                 goto dont_know;
 764
 765         u = timespec_load(&st.st_atim);
 766         n = now(CLOCK_REALTIME);
 767         b = u + IDLE_THRESHOLD_USEC < n;
 768
 769         if (t)
 770                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 771
 772         return b;
 773
 774 dont_know:
 775         if (t)
 776                 *t = s->idle_hint_timestamp;
 777
 778         return 0;
 779 }
 780
 781 void session_set_idle_hint(Session *s, bool b) {
 782         assert(s);
 783
 784         if (s->idle_hint == b)
 785                 return;
 786
 787         s->idle_hint = b;
 788         dual_timestamp_get(&s->idle_hint_timestamp);
 789
 790         session_send_changed(s,
 791                              "IdleHint\0"
 792                              "IdleSinceHint\0"
 793                              "IdleSinceHintMonotonic\0");
 794
 795         if (s->seat)
 796                 seat_send_changed(s->seat,
 797                                   "IdleHint\0"
 798                                   "IdleSinceHint\0"
 799                                   "IdleSinceHintMonotonic\0");
 800
 801         user_send_changed(s->user,
 802                           "IdleHint\0"
 803                           "IdleSinceHint\0"
 804                           "IdleSinceHintMonotonic\0");
 805
 806         manager_send_changed(s->manager,
 807                              "IdleHint\0"
 808                              "IdleSinceHint\0"
 809                              "IdleSinceHintMonotonic\0");
 810 }
 811
 812 int session_create_fifo(Session *s) {
 813         int r;
 814
 815         assert(s);
 816
 817         /* Create FIFO */
 818         if (!s->fifo_path) {
 819                 r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 820                 if (r < 0)
 821                         return r;
 822
 823                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 824                         return -ENOMEM;
 825
 826                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 827                         return -errno;
 828         }
 829
 830         /* Open reading side */
 831         if (s->fifo_fd < 0) {
 832                 struct epoll_event ev;
 833
 834                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 835                 if (s->fifo_fd < 0)
 836                         return -errno;
 837
 838                 r = hashmap_put(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1), s);
 839                 if (r < 0)
 840                         return r;
 841
 842                 zero(ev);
 843                 ev.events = 0;
 844                 ev.data.u32 = FD_FIFO_BASE + s->fifo_fd;
 845
 846                 if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
 847                         return -errno;
 848         }
 849
 850         /* Open writing side */
 851         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 852         if (r < 0)
 853                 return -errno;
 854
 855         return r;
 856 }
 857
 858 void session_remove_fifo(Session *s) {
 859         assert(s);
 860
 861         if (s->fifo_fd >= 0) {
 862                 assert_se(hashmap_remove(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
 863                 assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
 864                 close_nointr_nofail(s->fifo_fd);
 865                 s->fifo_fd = -1;
 866         }
 867
 868         if (s->fifo_path) {
 869                 unlink(s->fifo_path);
 870                 free(s->fifo_path);
 871                 s->fifo_path = NULL;
 872         }
 873 }
 874
 875 int session_check_gc(Session *s, bool drop_not_started) {
 876         int r;
 877
 878         assert(s);
 879
 880         if (drop_not_started && !s->started)
 881                 return 0;
 882
 883         if (s->fifo_fd >= 0) {
 884
 885                 r = pipe_eof(s->fifo_fd);
 886                 if (r < 0)
 887                         return r;
 888
 889                 if (r == 0)
 890                         return 1;
 891         }
 892
 893         if (s->cgroup_path) {
 894
 895                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 896                 if (r < 0)
 897                         return r;
 898
 899                 if (r <= 0)
 900                         return 1;
 901         }
 902
 903         return 0;
 904 }
 905
 906 void session_add_to_gc_queue(Session *s) {
 907         assert(s);
 908
 909         if (s->in_gc_queue)
 910                 return;
 911
 912         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 913         s->in_gc_queue = true;
 914 }
 915
 916 int session_kill(Session *s, KillWho who, int signo) {
 917         int r = 0;
 918         Set *pid_set = NULL;
 919
 920         assert(s);
 921
 922         if (!s->cgroup_path)
 923                 return -ESRCH;
 924
 925         if (s->leader <= 0 && who == KILL_LEADER)
 926                 return -ESRCH;
 927
 928         if (s->leader > 0)
 929                 if (kill(s->leader, signo) < 0)
 930                         r = -errno;
 931
 932         if (who == KILL_ALL) {
 933                 int q;
 934
 935                 pid_set = set_new(trivial_hash_func, trivial_compare_func);
 936                 if (!pid_set)
 937                         return -ENOMEM;
 938
 939                 if (s->leader > 0) {
 940                         q = set_put(pid_set, LONG_TO_PTR(s->leader));
 941                         if (q < 0)
 942                                 r = q;
 943                 }
 944
 945                 q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, signo, false, true, false, pid_set);
 946                 if (q < 0)
 947                         if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
 948                                 r = q;
 949         }
 950
 951         if (pid_set)
 952                 set_free(pid_set);
 953
 954         return r;
 955 }
 956
 957 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 958         [SESSION_TTY] = "tty",
 959         [SESSION_X11] = "x11",
 960         [SESSION_UNSPECIFIED] = "unspecified"
 961 };
 962
 963 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
 964
 965 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
 966         [SESSION_USER] = "user",
 967         [SESSION_GREETER] = "greeter",
 968         [SESSION_LOCK_SCREEN] = "lock-screen"
 969 };
 970
 971 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
 972
 973 static const char* const kill_who_table[_KILL_WHO_MAX] = {
 974         [KILL_LEADER] = "leader",
 975         [KILL_ALL] = "all"
 976 };
 977
 978 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);