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 "mkdir.h"
  32 #include "cgroup-util.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->id);
  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
 103         session_remove_fifo(s);
 104
 105         free(s->state_file);
 106         free(s);
 107 }
 108
 109 int session_save(Session *s) {
 110         FILE *f;
 111         int r = 0;
 112         char *temp_path;
 113
 114         assert(s);
 115
 116         if (!s->started)
 117                 return 0;
 118
 119         r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 120         if (r < 0)
 121                 goto finish;
 122
 123         r = fopen_temporary(s->state_file, &f, &temp_path);
 124         if (r < 0)
 125                 goto finish;
 126
 127         assert(s->user);
 128
 129         fchmod(fileno(f), 0644);
 130
 131         fprintf(f,
 132                 "# This is private data. Do not parse.\n"
 133                 "UID=%lu\n"
 134                 "USER=%s\n"
 135                 "ACTIVE=%i\n"
 136                 "REMOTE=%i\n"
 137                 "KILL_PROCESSES=%i\n",
 138                 (unsigned long) s->user->uid,
 139                 s->user->name,
 140                 session_is_active(s),
 141                 s->remote,
 142                 s->kill_processes);
 143
 144         if (s->type >= 0)
 145                 fprintf(f,
 146                         "TYPE=%s\n",
 147                         session_type_to_string(s->type));
 148
 149         if (s->class >= 0)
 150                 fprintf(f,
 151                         "CLASS=%s\n",
 152                         session_class_to_string(s->class));
 153
 154         if (s->cgroup_path)
 155                 fprintf(f,
 156                         "CGROUP=%s\n",
 157                         s->cgroup_path);
 158
 159         if (s->fifo_path)
 160                 fprintf(f,
 161                         "FIFO=%s\n",
 162                         s->fifo_path);
 163
 164         if (s->seat)
 165                 fprintf(f,
 166                         "SEAT=%s\n",
 167                         s->seat->id);
 168
 169         if (s->tty)
 170                 fprintf(f,
 171                         "TTY=%s\n",
 172                         s->tty);
 173
 174         if (s->display)
 175                 fprintf(f,
 176                         "DISPLAY=%s\n",
 177                         s->display);
 178
 179         if (s->remote_host)
 180                 fprintf(f,
 181                         "REMOTE_HOST=%s\n",
 182                         s->remote_host);
 183
 184         if (s->remote_user)
 185                 fprintf(f,
 186                         "REMOTE_USER=%s\n",
 187                         s->remote_user);
 188
 189         if (s->service)
 190                 fprintf(f,
 191                         "SERVICE=%s\n",
 192                         s->service);
 193
 194         if (s->seat && seat_can_multi_session(s->seat))
 195                 fprintf(f,
 196                         "VTNR=%i\n",
 197                         s->vtnr);
 198
 199         if (s->leader > 0)
 200                 fprintf(f,
 201                         "LEADER=%lu\n",
 202                         (unsigned long) s->leader);
 203
 204         if (s->audit_id > 0)
 205                 fprintf(f,
 206                         "AUDIT=%llu\n",
 207                         (unsigned long long) s->audit_id);
 208
 209         fflush(f);
 210
 211         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 212                 r = -errno;
 213                 unlink(s->state_file);
 214                 unlink(temp_path);
 215         }
 216
 217         fclose(f);
 218         free(temp_path);
 219
 220 finish:
 221         if (r < 0)
 222                 log_error("Failed to save session data for %s: %s", s->id, strerror(-r));
 223
 224         return r;
 225 }
 226
 227 int session_load(Session *s) {
 228         char *remote = NULL,
 229                 *kill_processes = NULL,
 230                 *seat = NULL,
 231                 *vtnr = NULL,
 232                 *leader = NULL,
 233                 *audit_id = NULL,
 234                 *type = NULL,
 235                 *class = NULL;
 236
 237         int k, r;
 238
 239         assert(s);
 240
 241         r = parse_env_file(s->state_file, NEWLINE,
 242                            "REMOTE",         &remote,
 243                            "KILL_PROCESSES", &kill_processes,
 244                            "CGROUP",         &s->cgroup_path,
 245                            "FIFO",           &s->fifo_path,
 246                            "SEAT",           &seat,
 247                            "TTY",            &s->tty,
 248                            "DISPLAY",        &s->display,
 249                            "REMOTE_HOST",    &s->remote_host,
 250                            "REMOTE_USER",    &s->remote_user,
 251                            "SERVICE",        &s->service,
 252                            "VTNR",           &vtnr,
 253                            "LEADER",         &leader,
 254                            "TYPE",           &type,
 255                            "CLASS",          &class,
 256                            NULL);
 257
 258         if (r < 0)
 259                 goto finish;
 260
 261         if (remote) {
 262                 k = parse_boolean(remote);
 263                 if (k >= 0)
 264                         s->remote = k;
 265         }
 266
 267         if (kill_processes) {
 268                 k = parse_boolean(kill_processes);
 269                 if (k >= 0)
 270                         s->kill_processes = k;
 271         }
 272
 273         if (seat && !s->seat) {
 274                 Seat *o;
 275
 276                 o = hashmap_get(s->manager->seats, seat);
 277                 if (o)
 278                         seat_attach_session(o, s);
 279         }
 280
 281         if (vtnr && s->seat && seat_can_multi_session(s->seat)) {
 282                 int v;
 283
 284                 k = safe_atoi(vtnr, &v);
 285                 if (k >= 0 && v >= 1)
 286                         s->vtnr = v;
 287         }
 288
 289         if (leader) {
 290                 pid_t pid;
 291
 292                 k = parse_pid(leader, &pid);
 293                 if (k >= 0 && pid >= 1) {
 294                         s->leader = pid;
 295
 296                         audit_session_from_pid(pid, &s->audit_id);
 297                 }
 298         }
 299
 300         if (type) {
 301                 SessionType t;
 302
 303                 t = session_type_from_string(type);
 304                 if (t >= 0)
 305                         s->type = t;
 306         }
 307
 308         if (class) {
 309                 SessionClass c;
 310
 311                 c = session_class_from_string(class);
 312                 if (c >= 0)
 313                         s->class = c;
 314         }
 315
 316         if (s->fifo_path) {
 317                 int fd;
 318
 319                 /* If we open an unopened pipe for reading we will not
 320                    get an EOF. to trigger an EOF we hence open it for
 321                    reading, but close it right-away which then will
 322                    trigger the EOF. */
 323
 324                 fd = session_create_fifo(s);
 325                 if (fd >= 0)
 326                         close_nointr_nofail(fd);
 327         }
 328
 329
 330 finish:
 331         free(remote);
 332         free(kill_processes);
 333         free(seat);
 334         free(vtnr);
 335         free(leader);
 336         free(audit_id);
 337
 338         return r;
 339 }
 340
 341 int session_activate(Session *s) {
 342         int r;
 343
 344         assert(s);
 345
 346         if (s->vtnr < 0)
 347                 return -ENOTSUP;
 348
 349         if (!s->seat)
 350                 return -ENOTSUP;
 351
 352         if (s->seat->active == s)
 353                 return 0;
 354
 355         assert(seat_is_vtconsole(s->seat));
 356
 357         r = chvt(s->vtnr);
 358         if (r < 0)
 359                 return r;
 360
 361         return seat_set_active(s->seat, s);
 362 }
 363
 364 static int session_link_x11_socket(Session *s) {
 365         char *t, *f, *c;
 366         size_t k;
 367
 368         assert(s);
 369         assert(s->user);
 370         assert(s->user->runtime_path);
 371
 372         if (s->user->display)
 373                 return 0;
 374
 375         if (!s->display || !display_is_local(s->display))
 376                 return 0;
 377
 378         k = strspn(s->display+1, "0123456789");
 379         f = new(char, sizeof("/tmp/.X11-unix/X") + k);
 380         if (!f) {
 381                 log_error("Out of memory");
 382                 return -ENOMEM;
 383         }
 384
 385         c = stpcpy(f, "/tmp/.X11-unix/X");
 386         memcpy(c, s->display+1, k);
 387         c[k] = 0;
 388
 389         if (access(f, F_OK) < 0) {
 390                 log_warning("Session %s has display %s with nonexisting socket %s.", s->id, s->display, f);
 391                 free(f);
 392                 return -ENOENT;
 393         }
 394
 395         /* Note that this cannot be in a subdir to avoid
 396          * vulnerabilities since we are privileged but the runtime
 397          * path is owned by the user */
 398
 399         t = strappend(s->user->runtime_path, "/X11-display");
 400         if (!t) {
 401                 log_error("Out of memory");
 402                 free(f);
 403                 return -ENOMEM;
 404         }
 405
 406         if (link(f, t) < 0) {
 407                 if (errno == EEXIST) {
 408                         unlink(t);
 409
 410                         if (link(f, t) >= 0)
 411                                 goto done;
 412                 }
 413
 414                 if (symlink(f, t) < 0) {
 415
 416                         if (errno == EEXIST) {
 417                                 unlink(t);
 418
 419                                 if (symlink(f, t) >= 0)
 420                                         goto done;
 421                         }
 422
 423                         log_error("Failed to link %s to %s: %m", f, t);
 424                         free(f);
 425                         free(t);
 426                         return -errno;
 427                 }
 428         }
 429
 430 done:
 431         log_info("Linked %s to %s.", f, t);
 432         free(f);
 433         free(t);
 434
 435         s->user->display = s;
 436
 437         return 0;
 438 }
 439
 440 static int session_create_one_group(Session *s, const char *controller, const char *path) {
 441         int r;
 442
 443         assert(s);
 444         assert(controller);
 445         assert(path);
 446
 447         if (s->leader > 0) {
 448                 r = cg_create_and_attach(controller, path, s->leader);
 449                 if (r < 0)
 450                         r = cg_create(controller, path);
 451         } else
 452                 r = cg_create(controller, path);
 453
 454         if (r < 0)
 455                 return r;
 456
 457         r = cg_set_task_access(controller, path, 0644, s->user->uid, s->user->gid, -1);
 458         if (r >= 0)
 459                 r = cg_set_group_access(controller, path, 0755, s->user->uid, s->user->gid);
 460
 461         return r;
 462 }
 463
 464 static int session_create_cgroup(Session *s) {
 465         char **k;
 466         char *p;
 467         int r;
 468
 469         assert(s);
 470         assert(s->user);
 471         assert(s->user->cgroup_path);
 472
 473         if (!s->cgroup_path) {
 474                 if (asprintf(&p, "%s/%s", s->user->cgroup_path, s->id) < 0) {
 475                         log_error("Out of memory");
 476                         return -ENOMEM;
 477                 }
 478         } else
 479                 p = s->cgroup_path;
 480
 481         r = session_create_one_group(s, SYSTEMD_CGROUP_CONTROLLER, p);
 482         if (r < 0) {
 483                 log_error("Failed to create "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r));
 484                 free(p);
 485                 s->cgroup_path = NULL;
 486                 return r;
 487         }
 488
 489         s->cgroup_path = p;
 490
 491         STRV_FOREACH(k, s->controllers) {
 492
 493                 if (strv_contains(s->reset_controllers, *k))
 494                         continue;
 495
 496                 r = session_create_one_group(s, *k, p);
 497                 if (r < 0)
 498                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 499         }
 500
 501         STRV_FOREACH(k, s->manager->controllers) {
 502
 503                 if (strv_contains(s->reset_controllers, *k) ||
 504                     strv_contains(s->manager->reset_controllers, *k) ||
 505                     strv_contains(s->controllers, *k))
 506                         continue;
 507
 508                 r = session_create_one_group(s, *k, p);
 509                 if (r < 0)
 510                         log_warning("Failed to create %s:%s: %s", *k, p, strerror(-r));
 511         }
 512
 513         if (s->leader > 0) {
 514
 515                 STRV_FOREACH(k, s->reset_controllers) {
 516                         r = cg_attach(*k, "/", s->leader);
 517                         if (r < 0)
 518                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 519
 520                 }
 521
 522                 STRV_FOREACH(k, s->manager->reset_controllers) {
 523
 524                         if (strv_contains(s->reset_controllers, *k) ||
 525                             strv_contains(s->controllers, *k))
 526                                 continue;
 527
 528                         r = cg_attach(*k, "/", s->leader);
 529                         if (r < 0)
 530                                 log_warning("Failed to reset controller %s: %s", *k, strerror(-r));
 531
 532                 }
 533         }
 534
 535         hashmap_put(s->manager->cgroups, s->cgroup_path, s);
 536
 537         return 0;
 538 }
 539
 540 int session_start(Session *s) {
 541         int r;
 542
 543         assert(s);
 544         assert(s->user);
 545
 546         if (s->started)
 547                 return 0;
 548
 549         r = user_start(s->user);
 550         if (r < 0)
 551                 return r;
 552
 553         log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 554                  "New session %s of user %s.", s->id, s->user->name);
 555
 556         /* Create cgroup */
 557         r = session_create_cgroup(s);
 558         if (r < 0)
 559                 return r;
 560
 561         /* Create X11 symlink */
 562         session_link_x11_socket(s);
 563
 564         dual_timestamp_get(&s->timestamp);
 565
 566         if (s->seat)
 567                 seat_read_active_vt(s->seat);
 568
 569         s->started = true;
 570
 571         /* Save session data */
 572         session_save(s);
 573         user_save(s->user);
 574
 575         session_send_signal(s, true);
 576
 577         if (s->seat) {
 578                 seat_save(s->seat);
 579
 580                 if (s->seat->active == s)
 581                         seat_send_changed(s->seat, "Sessions\0ActiveSession\0");
 582                 else
 583                         seat_send_changed(s->seat, "Sessions\0");
 584         }
 585
 586         user_send_changed(s->user, "Sessions\0");
 587
 588         return 0;
 589 }
 590
 591 static bool session_shall_kill(Session *s) {
 592         assert(s);
 593
 594         if (!s->kill_processes)
 595                 return false;
 596
 597         if (strv_contains(s->manager->kill_exclude_users, s->user->name))
 598                 return false;
 599
 600         if (strv_isempty(s->manager->kill_only_users))
 601                 return true;
 602
 603         return strv_contains(s->manager->kill_only_users, s->user->name);
 604 }
 605
 606 static int session_terminate_cgroup(Session *s) {
 607         int r;
 608         char **k;
 609
 610         assert(s);
 611
 612         if (!s->cgroup_path)
 613                 return 0;
 614
 615         cg_trim(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 616
 617         if (session_shall_kill(s)) {
 618
 619                 r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 620                 if (r < 0)
 621                         log_error("Failed to kill session cgroup: %s", strerror(-r));
 622
 623         } else {
 624                 if (s->leader > 0) {
 625                         Session *t;
 626
 627                         /* We still send a HUP to the leader process,
 628                          * even if we are not supposed to kill the
 629                          * whole cgroup. But let's first check the
 630                          * leader still exists and belongs to our
 631                          * session... */
 632
 633                         r = manager_get_session_by_pid(s->manager, s->leader, &t);
 634                         if (r > 0 && t == s) {
 635                                 kill(s->leader, SIGTERM); /* for normal processes */
 636                                 kill(s->leader, SIGHUP);  /* for shells */
 637                                 kill(s->leader, SIGCONT); /* in case they are stopped */
 638                         }
 639                 }
 640
 641                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, true);
 642                 if (r < 0)
 643                         log_error("Failed to check session cgroup: %s", strerror(-r));
 644                 else if (r > 0) {
 645                         r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path);
 646                         if (r < 0)
 647                                 log_error("Failed to delete session cgroup: %s", strerror(-r));
 648                 }
 649         }
 650
 651         STRV_FOREACH(k, s->user->manager->controllers)
 652                 cg_trim(*k, s->cgroup_path, true);
 653
 654         hashmap_remove(s->manager->cgroups, s->cgroup_path);
 655
 656         free(s->cgroup_path);
 657         s->cgroup_path = NULL;
 658
 659         return 0;
 660 }
 661
 662 static int session_unlink_x11_socket(Session *s) {
 663         char *t;
 664         int r;
 665
 666         assert(s);
 667         assert(s->user);
 668
 669         if (s->user->display != s)
 670                 return 0;
 671
 672         s->user->display = NULL;
 673
 674         t = strappend(s->user->runtime_path, "/X11-display");
 675         if (!t) {
 676                 log_error("Out of memory");
 677                 return -ENOMEM;
 678         }
 679
 680         r = unlink(t);
 681         free(t);
 682
 683         return r < 0 ? -errno : 0;
 684 }
 685
 686 int session_stop(Session *s) {
 687         int r = 0, k;
 688
 689         assert(s);
 690
 691         if (s->started)
 692                 log_full(s->type == SESSION_TTY || s->type == SESSION_X11 ? LOG_INFO : LOG_DEBUG,
 693                          "Removed session %s.", s->id);
 694
 695         /* Kill cgroup */
 696         k = session_terminate_cgroup(s);
 697         if (k < 0)
 698                 r = k;
 699
 700         /* Remove X11 symlink */
 701         session_unlink_x11_socket(s);
 702
 703         unlink(s->state_file);
 704         session_add_to_gc_queue(s);
 705         user_add_to_gc_queue(s->user);
 706
 707         if (s->started)
 708                 session_send_signal(s, false);
 709
 710         if (s->seat) {
 711                 if (s->seat->active == s)
 712                         seat_set_active(s->seat, NULL);
 713
 714                 seat_send_changed(s->seat, "Sessions\0");
 715         }
 716
 717         user_send_changed(s->user, "Sessions\0");
 718
 719         s->started = false;
 720
 721         return r;
 722 }
 723
 724 bool session_is_active(Session *s) {
 725         assert(s);
 726
 727         if (!s->seat)
 728                 return true;
 729
 730         return s->seat->active == s;
 731 }
 732
 733 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 734         char *p;
 735         struct stat st;
 736         usec_t u, n;
 737         bool b;
 738         int k;
 739
 740         assert(s);
 741
 742         if (s->idle_hint) {
 743                 if (t)
 744                         *t = s->idle_hint_timestamp;
 745
 746                 return s->idle_hint;
 747         }
 748
 749         if (isempty(s->tty))
 750                 goto dont_know;
 751
 752         if (s->tty[0] != '/') {
 753                 p = strappend("/dev/", s->tty);
 754                 if (!p)
 755                         return -ENOMEM;
 756         } else
 757                 p = NULL;
 758
 759         if (!startswith(p ? p : s->tty, "/dev/")) {
 760                 free(p);
 761                 goto dont_know;
 762         }
 763
 764         k = lstat(p ? p : s->tty, &st);
 765         free(p);
 766
 767         if (k < 0)
 768                 goto dont_know;
 769
 770         u = timespec_load(&st.st_atim);
 771         n = now(CLOCK_REALTIME);
 772         b = u + IDLE_THRESHOLD_USEC < n;
 773
 774         if (t)
 775                 dual_timestamp_from_realtime(t, u + b ? IDLE_THRESHOLD_USEC : 0);
 776
 777         return b;
 778
 779 dont_know:
 780         if (t)
 781                 *t = s->idle_hint_timestamp;
 782
 783         return 0;
 784 }
 785
 786 void session_set_idle_hint(Session *s, bool b) {
 787         assert(s);
 788
 789         if (s->idle_hint == b)
 790                 return;
 791
 792         s->idle_hint = b;
 793         dual_timestamp_get(&s->idle_hint_timestamp);
 794
 795         session_send_changed(s,
 796                              "IdleHint\0"
 797                              "IdleSinceHint\0"
 798                              "IdleSinceHintMonotonic\0");
 799
 800         if (s->seat)
 801                 seat_send_changed(s->seat,
 802                                   "IdleHint\0"
 803                                   "IdleSinceHint\0"
 804                                   "IdleSinceHintMonotonic\0");
 805
 806         user_send_changed(s->user,
 807                           "IdleHint\0"
 808                           "IdleSinceHint\0"
 809                           "IdleSinceHintMonotonic\0");
 810
 811         manager_send_changed(s->manager,
 812                              "IdleHint\0"
 813                              "IdleSinceHint\0"
 814                              "IdleSinceHintMonotonic\0");
 815 }
 816
 817 int session_create_fifo(Session *s) {
 818         int r;
 819
 820         assert(s);
 821
 822         /* Create FIFO */
 823         if (!s->fifo_path) {
 824                 r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
 825                 if (r < 0)
 826                         return r;
 827
 828                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 829                         return -ENOMEM;
 830
 831                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 832                         return -errno;
 833         }
 834
 835         /* Open reading side */
 836         if (s->fifo_fd < 0) {
 837                 struct epoll_event ev;
 838
 839                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 840                 if (s->fifo_fd < 0)
 841                         return -errno;
 842
 843                 r = hashmap_put(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1), s);
 844                 if (r < 0)
 845                         return r;
 846
 847                 zero(ev);
 848                 ev.events = 0;
 849                 ev.data.u32 = FD_FIFO_BASE + s->fifo_fd;
 850
 851                 if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
 852                         return -errno;
 853         }
 854
 855         /* Open writing side */
 856         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 857         if (r < 0)
 858                 return -errno;
 859
 860         return r;
 861 }
 862
 863 void session_remove_fifo(Session *s) {
 864         assert(s);
 865
 866         if (s->fifo_fd >= 0) {
 867                 assert_se(hashmap_remove(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
 868                 assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
 869                 close_nointr_nofail(s->fifo_fd);
 870                 s->fifo_fd = -1;
 871         }
 872
 873         if (s->fifo_path) {
 874                 unlink(s->fifo_path);
 875                 free(s->fifo_path);
 876                 s->fifo_path = NULL;
 877         }
 878 }
 879
 880 int session_check_gc(Session *s, bool drop_not_started) {
 881         int r;
 882
 883         assert(s);
 884
 885         if (drop_not_started && !s->started)
 886                 return 0;
 887
 888         if (s->fifo_fd >= 0) {
 889
 890                 r = pipe_eof(s->fifo_fd);
 891                 if (r < 0)
 892                         return r;
 893
 894                 if (r == 0)
 895                         return 1;
 896         }
 897
 898         if (s->cgroup_path) {
 899
 900                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, false);
 901                 if (r < 0)
 902                         return r;
 903
 904                 if (r <= 0)
 905                         return 1;
 906         }
 907
 908         return 0;
 909 }
 910
 911 void session_add_to_gc_queue(Session *s) {
 912         assert(s);
 913
 914         if (s->in_gc_queue)
 915                 return;
 916
 917         LIST_PREPEND(Session, gc_queue, s->manager->session_gc_queue, s);
 918         s->in_gc_queue = true;
 919 }
 920
 921 int session_kill(Session *s, KillWho who, int signo) {
 922         int r = 0;
 923         Set *pid_set = NULL;
 924
 925         assert(s);
 926
 927         if (!s->cgroup_path)
 928                 return -ESRCH;
 929
 930         if (s->leader <= 0 && who == KILL_LEADER)
 931                 return -ESRCH;
 932
 933         if (s->leader > 0)
 934                 if (kill(s->leader, signo) < 0)
 935                         r = -errno;
 936
 937         if (who == KILL_ALL) {
 938                 int q;
 939
 940                 pid_set = set_new(trivial_hash_func, trivial_compare_func);
 941                 if (!pid_set)
 942                         return -ENOMEM;
 943
 944                 if (s->leader > 0) {
 945                         q = set_put(pid_set, LONG_TO_PTR(s->leader));
 946                         if (q < 0)
 947                                 r = q;
 948                 }
 949
 950                 q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, s->cgroup_path, signo, false, true, false, pid_set);
 951                 if (q < 0)
 952                         if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
 953                                 r = q;
 954         }
 955
 956         if (pid_set)
 957                 set_free(pid_set);
 958
 959         return r;
 960 }
 961
 962 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
 963         [SESSION_TTY] = "tty",
 964         [SESSION_X11] = "x11",
 965         [SESSION_UNSPECIFIED] = "unspecified"
 966 };
 967
 968 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
 969
 970 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
 971         [SESSION_USER] = "user",
 972         [SESSION_GREETER] = "greeter",
 973         [SESSION_LOCK_SCREEN] = "lock-screen"
 974 };
 975
 976 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
 977
 978 static const char* const kill_who_table[_KILL_WHO_MAX] = {
 979         [KILL_LEADER] = "leader",
 980         [KILL_ALL] = "all"
 981 };
 982
 983 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);