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 <fcntl.h>
  24 #include <linux/vt.h>
  25 #include <linux/kd.h>
  26 #include <signal.h>
  27 #include <string.h>
  28 #include <sys/ioctl.h>
  29 #include <unistd.h>
  30
  31 #include "sd-messages.h"
  32 #include "util.h"
  33 #include "mkdir.h"
  34 #include "path-util.h"
  35 #include "fileio.h"
  36 #include "audit.h"
  37 #include "bus-util.h"
  38 #include "bus-error.h"
  39 #include "logind-session.h"
  40 #include "formats-util.h"
  41 #include "terminal-util.h"
  42
  43 #define RELEASE_USEC (20*USEC_PER_SEC)
  44
  45 static void session_remove_fifo(Session *s);
  46
  47 Session* session_new(Manager *m, const char *id) {
  48         Session *s;
  49
  50         assert(m);
  51         assert(id);
  52         assert(session_id_valid(id));
  53
  54         s = new0(Session, 1);
  55         if (!s)
  56                 return NULL;
  57
  58         s->state_file = strappend("/run/systemd/sessions/", id);
  59         if (!s->state_file) {
  60                 free(s);
  61                 return NULL;
  62         }
  63
  64         s->devices = hashmap_new(&devt_hash_ops);
  65         if (!s->devices) {
  66                 free(s->state_file);
  67                 free(s);
  68                 return NULL;
  69         }
  70
  71         s->id = basename(s->state_file);
  72
  73         if (hashmap_put(m->sessions, s->id, s) < 0) {
  74                 hashmap_free(s->devices);
  75                 free(s->state_file);
  76                 free(s);
  77                 return NULL;
  78         }
  79
  80         s->manager = m;
  81         s->fifo_fd = -1;
  82         s->vtfd = -1;
  83
  84         return s;
  85 }
  86
  87 void session_free(Session *s) {
  88         SessionDevice *sd;
  89
  90         assert(s);
  91
  92         if (s->in_gc_queue)
  93                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
  94
  95         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  96
  97         session_remove_fifo(s);
  98
  99         session_drop_controller(s);
 100
 101         while ((sd = hashmap_first(s->devices)))
 102                 session_device_free(sd);
 103
 104         hashmap_free(s->devices);
 105
 106         if (s->user) {
 107                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 108
 109                 if (s->user->display == s)
 110                         s->user->display = NULL;
 111         }
 112
 113         if (s->seat) {
 114                 if (s->seat->active == s)
 115                         s->seat->active = NULL;
 116                 if (s->seat->pending_switch == s)
 117                         s->seat->pending_switch = NULL;
 118
 119                 seat_evict_position(s->seat, s);
 120                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 121         }
 122
 123         if (s->scope) {
 124                 hashmap_remove(s->manager->session_units, s->scope);
 125                 free(s->scope);
 126         }
 127
 128         free(s->scope_job);
 129
 130         sd_bus_message_unref(s->create_message);
 131
 132         free(s->tty);
 133         free(s->display);
 134         free(s->remote_host);
 135         free(s->remote_user);
 136         free(s->service);
 137         free(s->desktop);
 138
 139         hashmap_remove(s->manager->sessions, s->id);
 140
 141         free(s->state_file);
 142         free(s);
 143 }
 144
 145 void session_set_user(Session *s, User *u) {
 146         assert(s);
 147         assert(!s->user);
 148
 149         s->user = u;
 150         LIST_PREPEND(sessions_by_user, u->sessions, s);
 151 }
 152
 153 int session_save(Session *s) {
 154         _cleanup_free_ char *temp_path = NULL;
 155         _cleanup_fclose_ FILE *f = NULL;
 156         int r = 0;
 157
 158         assert(s);
 159
 160         if (!s->user)
 161                 return -ESTALE;
 162
 163         if (!s->started)
 164                 return 0;
 165
 166         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 167         if (r < 0)
 168                 goto fail;
 169
 170         r = fopen_temporary(s->state_file, &f, &temp_path);
 171         if (r < 0)
 172                 goto fail;
 173
 174         assert(s->user);
 175
 176         fchmod(fileno(f), 0644);
 177
 178         fprintf(f,
 179                 "# This is private data. Do not parse.\n"
 180                 "UID="UID_FMT"\n"
 181                 "USER=%s\n"
 182                 "ACTIVE=%i\n"
 183                 "STATE=%s\n"
 184                 "REMOTE=%i\n",
 185                 s->user->uid,
 186                 s->user->name,
 187                 session_is_active(s),
 188                 session_state_to_string(session_get_state(s)),
 189                 s->remote);
 190
 191         if (s->type >= 0)
 192                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 193
 194         if (s->class >= 0)
 195                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 196
 197         if (s->scope)
 198                 fprintf(f, "SCOPE=%s\n", s->scope);
 199         if (s->scope_job)
 200                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 201
 202         if (s->fifo_path)
 203                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 204
 205         if (s->seat)
 206                 fprintf(f, "SEAT=%s\n", s->seat->id);
 207
 208         if (s->tty)
 209                 fprintf(f, "TTY=%s\n", s->tty);
 210
 211         if (s->display)
 212                 fprintf(f, "DISPLAY=%s\n", s->display);
 213
 214         if (s->remote_host) {
 215                 _cleanup_free_ char *escaped;
 216
 217                 escaped = cescape(s->remote_host);
 218                 if (!escaped) {
 219                         r = -ENOMEM;
 220                         goto fail;
 221                 }
 222
 223                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 224         }
 225
 226         if (s->remote_user) {
 227                 _cleanup_free_ char *escaped;
 228
 229                 escaped = cescape(s->remote_user);
 230                 if (!escaped) {
 231                         r = -ENOMEM;
 232                         goto fail;
 233                 }
 234
 235                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 236         }
 237
 238         if (s->service) {
 239                 _cleanup_free_ char *escaped;
 240
 241                 escaped = cescape(s->service);
 242                 if (!escaped) {
 243                         r = -ENOMEM;
 244                         goto fail;
 245                 }
 246
 247                 fprintf(f, "SERVICE=%s\n", escaped);
 248         }
 249
 250         if (s->desktop) {
 251                 _cleanup_free_ char *escaped;
 252
 253
 254                 escaped = cescape(s->desktop);
 255                 if (!escaped) {
 256                         r = -ENOMEM;
 257                         goto fail;
 258                 }
 259
 260                 fprintf(f, "DESKTOP=%s\n", escaped);
 261         }
 262
 263         if (s->seat && seat_has_vts(s->seat))
 264                 fprintf(f, "VTNR=%u\n", s->vtnr);
 265
 266         if (!s->vtnr)
 267                 fprintf(f, "POSITION=%u\n", s->position);
 268
 269         if (s->leader > 0)
 270                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 271
 272         if (s->audit_id > 0)
 273                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 274
 275         if (dual_timestamp_is_set(&s->timestamp))
 276                 fprintf(f,
 277                         "REALTIME="USEC_FMT"\n"
 278                         "MONOTONIC="USEC_FMT"\n",
 279                         s->timestamp.realtime,
 280                         s->timestamp.monotonic);
 281
 282         if (s->controller)
 283                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 284
 285         r = fflush_and_check(f);
 286         if (r < 0)
 287                 goto fail;
 288
 289         if (rename(temp_path, s->state_file) < 0) {
 290                 r = -errno;
 291                 goto fail;
 292         }
 293
 294         return 0;
 295
 296 fail:
 297         (void) unlink(s->state_file);
 298
 299         if (temp_path)
 300                 (void) unlink(temp_path);
 301
 302         return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 303 }
 304
 305
 306 int session_load(Session *s) {
 307         _cleanup_free_ char *remote = NULL,
 308                 *seat = NULL,
 309                 *vtnr = NULL,
 310                 *state = NULL,
 311                 *position = NULL,
 312                 *leader = NULL,
 313                 *type = NULL,
 314                 *class = NULL,
 315                 *uid = NULL,
 316                 *realtime = NULL,
 317                 *monotonic = NULL,
 318                 *controller = NULL;
 319
 320         int k, r;
 321
 322         assert(s);
 323
 324         r = parse_env_file(s->state_file, NEWLINE,
 325                            "REMOTE",         &remote,
 326                            "SCOPE",          &s->scope,
 327                            "SCOPE_JOB",      &s->scope_job,
 328                            "FIFO",           &s->fifo_path,
 329                            "SEAT",           &seat,
 330                            "TTY",            &s->tty,
 331                            "DISPLAY",        &s->display,
 332                            "REMOTE_HOST",    &s->remote_host,
 333                            "REMOTE_USER",    &s->remote_user,
 334                            "SERVICE",        &s->service,
 335                            "DESKTOP",        &s->desktop,
 336                            "VTNR",           &vtnr,
 337                            "STATE",          &state,
 338                            "POSITION",       &position,
 339                            "LEADER",         &leader,
 340                            "TYPE",           &type,
 341                            "CLASS",          &class,
 342                            "UID",            &uid,
 343                            "REALTIME",       &realtime,
 344                            "MONOTONIC",      &monotonic,
 345                            "CONTROLLER",     &controller,
 346                            NULL);
 347
 348         if (r < 0)
 349                 return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 350
 351         if (!s->user) {
 352                 uid_t u;
 353                 User *user;
 354
 355                 if (!uid) {
 356                         log_error("UID not specified for session %s", s->id);
 357                         return -ENOENT;
 358                 }
 359
 360                 r = parse_uid(uid, &u);
 361                 if (r < 0)  {
 362                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 363                         return r;
 364                 }
 365
 366                 user = hashmap_get(s->manager->users, UID_TO_PTR(u));
 367                 if (!user) {
 368                         log_error("User of session %s not known.", s->id);
 369                         return -ENOENT;
 370                 }
 371
 372                 session_set_user(s, user);
 373         }
 374
 375         if (remote) {
 376                 k = parse_boolean(remote);
 377                 if (k >= 0)
 378                         s->remote = k;
 379         }
 380
 381         if (vtnr)
 382                 safe_atou(vtnr, &s->vtnr);
 383
 384         if (seat && !s->seat) {
 385                 Seat *o;
 386
 387                 o = hashmap_get(s->manager->seats, seat);
 388                 if (o)
 389                         r = seat_attach_session(o, s);
 390                 if (!o || r < 0)
 391                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 392         }
 393
 394         if (!s->seat || !seat_has_vts(s->seat))
 395                 s->vtnr = 0;
 396
 397         if (position && s->seat) {
 398                 unsigned int npos;
 399
 400                 safe_atou(position, &npos);
 401                 seat_claim_position(s->seat, s, npos);
 402         }
 403
 404         if (leader) {
 405                 k = parse_pid(leader, &s->leader);
 406                 if (k >= 0)
 407                         audit_session_from_pid(s->leader, &s->audit_id);
 408         }
 409
 410         if (type) {
 411                 SessionType t;
 412
 413                 t = session_type_from_string(type);
 414                 if (t >= 0)
 415                         s->type = t;
 416         }
 417
 418         if (class) {
 419                 SessionClass c;
 420
 421                 c = session_class_from_string(class);
 422                 if (c >= 0)
 423                         s->class = c;
 424         }
 425
 426         if (state && streq(state, "closing"))
 427                 s->stopping = true;
 428
 429         if (s->fifo_path) {
 430                 int fd;
 431
 432                 /* If we open an unopened pipe for reading we will not
 433                    get an EOF. to trigger an EOF we hence open it for
 434                    writing, but close it right away which then will
 435                    trigger the EOF. This will happen immediately if no
 436                    other process has the FIFO open for writing, i. e.
 437                    when the session died before logind (re)started. */
 438
 439                 fd = session_create_fifo(s);
 440                 safe_close(fd);
 441         }
 442
 443         if (realtime) {
 444                 unsigned long long l;
 445                 if (sscanf(realtime, "%llu", &l) > 0)
 446                         s->timestamp.realtime = l;
 447         }
 448
 449         if (monotonic) {
 450                 unsigned long long l;
 451                 if (sscanf(monotonic, "%llu", &l) > 0)
 452                         s->timestamp.monotonic = l;
 453         }
 454
 455         if (controller) {
 456                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
 457                         session_set_controller(s, controller, false);
 458                 else
 459                         session_restore_vt(s);
 460         }
 461
 462         return r;
 463 }
 464
 465 int session_activate(Session *s) {
 466         unsigned int num_pending;
 467
 468         assert(s);
 469         assert(s->user);
 470
 471         if (!s->seat)
 472                 return -EOPNOTSUPP;
 473
 474         if (s->seat->active == s)
 475                 return 0;
 476
 477         /* on seats with VTs, we let VTs manage session-switching */
 478         if (seat_has_vts(s->seat)) {
 479                 if (!s->vtnr)
 480                         return -EOPNOTSUPP;
 481
 482                 return chvt(s->vtnr);
 483         }
 484
 485         /* On seats without VTs, we implement session-switching in logind. We
 486          * try to pause all session-devices and wait until the session
 487          * controller acknowledged them. Once all devices are asleep, we simply
 488          * switch the active session and be done.
 489          * We save the session we want to switch to in seat->pending_switch and
 490          * seat_complete_switch() will perform the final switch. */
 491
 492         s->seat->pending_switch = s;
 493
 494         /* if no devices are running, immediately perform the session switch */
 495         num_pending = session_device_try_pause_all(s);
 496         if (!num_pending)
 497                 seat_complete_switch(s->seat);
 498
 499         return 0;
 500 }
 501
 502 static int session_start_scope(Session *s) {
 503         int r;
 504
 505         assert(s);
 506         assert(s->user);
 507         assert(s->user->slice);
 508
 509         if (!s->scope) {
 510                 _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 511                 _cleanup_free_ char *description = NULL;
 512                 char *scope, *job = NULL;
 513
 514                 description = strjoin("Session ", s->id, " of user ", s->user->name, NULL);
 515                 if (!description)
 516                         return log_oom();
 517
 518                 scope = strjoin("session-", s->id, ".scope", NULL);
 519                 if (!scope)
 520                         return log_oom();
 521
 522                 r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-logind.service", "systemd-user-sessions.service", &error, &job);
 523                 if (r < 0) {
 524                         log_error("Failed to start session scope %s: %s %s",
 525                                   scope, bus_error_message(&error, r), error.name);
 526                         free(scope);
 527                         return r;
 528                 } else {
 529                         s->scope = scope;
 530
 531                         free(s->scope_job);
 532                         s->scope_job = job;
 533                 }
 534         }
 535
 536         if (s->scope)
 537                 hashmap_put(s->manager->session_units, s->scope, s);
 538
 539         return 0;
 540 }
 541
 542 int session_start(Session *s) {
 543         int r;
 544
 545         assert(s);
 546
 547         if (!s->user)
 548                 return -ESTALE;
 549
 550         if (s->started)
 551                 return 0;
 552
 553         r = user_start(s->user);
 554         if (r < 0)
 555                 return r;
 556
 557         /* Create cgroup */
 558         r = session_start_scope(s);
 559         if (r < 0)
 560                 return r;
 561
 562         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 563                    LOG_MESSAGE_ID(SD_MESSAGE_SESSION_START),
 564                    "SESSION_ID=%s", s->id,
 565                    "USER_ID=%s", s->user->name,
 566                    "LEADER="PID_FMT, s->leader,
 567                    LOG_MESSAGE("New session %s of user %s.", s->id, s->user->name),
 568                    NULL);
 569
 570         if (!dual_timestamp_is_set(&s->timestamp))
 571                 dual_timestamp_get(&s->timestamp);
 572
 573         if (s->seat)
 574                 seat_read_active_vt(s->seat);
 575
 576         s->started = true;
 577
 578         user_elect_display(s->user);
 579
 580         /* Save data */
 581         session_save(s);
 582         user_save(s->user);
 583         if (s->seat)
 584                 seat_save(s->seat);
 585
 586         /* Send signals */
 587         session_send_signal(s, true);
 588         user_send_changed(s->user, "Sessions", "Display", NULL);
 589         if (s->seat) {
 590                 if (s->seat->active == s)
 591                         seat_send_changed(s->seat, "Sessions", "ActiveSession", NULL);
 592                 else
 593                         seat_send_changed(s->seat, "Sessions", NULL);
 594         }
 595
 596         return 0;
 597 }
 598
 599 static int session_stop_scope(Session *s, bool force) {
 600         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 601         char *job = NULL;
 602         int r;
 603
 604         assert(s);
 605
 606         if (!s->scope)
 607                 return 0;
 608
 609         if (force || manager_shall_kill(s->manager, s->user->name)) {
 610                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 611                 if (r < 0) {
 612                         log_error("Failed to stop session scope: %s", bus_error_message(&error, r));
 613                         return r;
 614                 }
 615
 616                 free(s->scope_job);
 617                 s->scope_job = job;
 618         } else {
 619                 r = manager_abandon_scope(s->manager, s->scope, &error);
 620                 if (r < 0) {
 621                         log_error("Failed to abandon session scope: %s", bus_error_message(&error, r));
 622                         return r;
 623                 }
 624         }
 625
 626         return 0;
 627 }
 628
 629 int session_stop(Session *s, bool force) {
 630         int r;
 631
 632         assert(s);
 633
 634         if (!s->user)
 635                 return -ESTALE;
 636
 637         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 638
 639         if (s->seat)
 640                 seat_evict_position(s->seat, s);
 641
 642         /* We are going down, don't care about FIFOs anymore */
 643         session_remove_fifo(s);
 644
 645         /* Kill cgroup */
 646         r = session_stop_scope(s, force);
 647
 648         s->stopping = true;
 649
 650         user_elect_display(s->user);
 651
 652         session_save(s);
 653         user_save(s->user);
 654
 655         return r;
 656 }
 657
 658 int session_finalize(Session *s) {
 659         int r = 0;
 660         SessionDevice *sd;
 661
 662         assert(s);
 663
 664         if (!s->user)
 665                 return -ESTALE;
 666
 667         if (s->started)
 668                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 669                            LOG_MESSAGE_ID(SD_MESSAGE_SESSION_STOP),
 670                            "SESSION_ID=%s", s->id,
 671                            "USER_ID=%s", s->user->name,
 672                            "LEADER="PID_FMT, s->leader,
 673                            LOG_MESSAGE("Removed session %s.", s->id),
 674                            NULL);
 675
 676         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 677
 678         if (s->seat)
 679                 seat_evict_position(s->seat, s);
 680
 681         /* Kill session devices */
 682         while ((sd = hashmap_first(s->devices)))
 683                 session_device_free(sd);
 684
 685         unlink(s->state_file);
 686         session_add_to_gc_queue(s);
 687         user_add_to_gc_queue(s->user);
 688
 689         if (s->started) {
 690                 session_send_signal(s, false);
 691                 s->started = false;
 692         }
 693
 694         if (s->seat) {
 695                 if (s->seat->active == s)
 696                         seat_set_active(s->seat, NULL);
 697
 698                 seat_save(s->seat);
 699                 seat_send_changed(s->seat, "Sessions", NULL);
 700         }
 701
 702         user_save(s->user);
 703         user_send_changed(s->user, "Sessions", "Display", NULL);
 704
 705         return r;
 706 }
 707
 708 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 709         Session *s = userdata;
 710
 711         assert(es);
 712         assert(s);
 713
 714         session_stop(s, false);
 715         return 0;
 716 }
 717
 718 int session_release(Session *s) {
 719         assert(s);
 720
 721         if (!s->started || s->stopping)
 722                 return 0;
 723
 724         if (s->timer_event_source)
 725                 return 0;
 726
 727         return sd_event_add_time(s->manager->event,
 728                                  &s->timer_event_source,
 729                                  CLOCK_MONOTONIC,
 730                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 731                                  release_timeout_callback, s);
 732 }
 733
 734 bool session_is_active(Session *s) {
 735         assert(s);
 736
 737         if (!s->seat)
 738                 return true;
 739
 740         return s->seat->active == s;
 741 }
 742
 743 static int get_tty_atime(const char *tty, usec_t *atime) {
 744         _cleanup_free_ char *p = NULL;
 745         struct stat st;
 746
 747         assert(tty);
 748         assert(atime);
 749
 750         if (!path_is_absolute(tty)) {
 751                 p = strappend("/dev/", tty);
 752                 if (!p)
 753                         return -ENOMEM;
 754
 755                 tty = p;
 756         } else if (!path_startswith(tty, "/dev/"))
 757                 return -ENOENT;
 758
 759         if (lstat(tty, &st) < 0)
 760                 return -errno;
 761
 762         *atime = timespec_load(&st.st_atim);
 763         return 0;
 764 }
 765
 766 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 767         _cleanup_free_ char *p = NULL;
 768         int r;
 769
 770         assert(pid > 0);
 771         assert(atime);
 772
 773         r = get_ctty(pid, NULL, &p);
 774         if (r < 0)
 775                 return r;
 776
 777         return get_tty_atime(p, atime);
 778 }
 779
 780 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 781         usec_t atime = 0, n;
 782         int r;
 783
 784         assert(s);
 785
 786         /* Explicit idle hint is set */
 787         if (s->idle_hint) {
 788                 if (t)
 789                         *t = s->idle_hint_timestamp;
 790
 791                 return s->idle_hint;
 792         }
 793
 794         /* Graphical sessions should really implement a real
 795          * idle hint logic */
 796         if (s->display)
 797                 goto dont_know;
 798
 799         /* For sessions with an explicitly configured tty, let's check
 800          * its atime */
 801         if (s->tty) {
 802                 r = get_tty_atime(s->tty, &atime);
 803                 if (r >= 0)
 804                         goto found_atime;
 805         }
 806
 807         /* For sessions with a leader but no explicitly configured
 808          * tty, let's check the controlling tty of the leader */
 809         if (s->leader > 0) {
 810                 r = get_process_ctty_atime(s->leader, &atime);
 811                 if (r >= 0)
 812                         goto found_atime;
 813         }
 814
 815 dont_know:
 816         if (t)
 817                 *t = s->idle_hint_timestamp;
 818
 819         return 0;
 820
 821 found_atime:
 822         if (t)
 823                 dual_timestamp_from_realtime(t, atime);
 824
 825         n = now(CLOCK_REALTIME);
 826
 827         if (s->manager->idle_action_usec <= 0)
 828                 return 0;
 829
 830         return atime + s->manager->idle_action_usec <= n;
 831 }
 832
 833 void session_set_idle_hint(Session *s, bool b) {
 834         assert(s);
 835
 836         if (s->idle_hint == b)
 837                 return;
 838
 839         s->idle_hint = b;
 840         dual_timestamp_get(&s->idle_hint_timestamp);
 841
 842         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 843
 844         if (s->seat)
 845                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 846
 847         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 848         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 849 }
 850
 851 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 852         Session *s = userdata;
 853
 854         assert(s);
 855         assert(s->fifo_fd == fd);
 856
 857         /* EOF on the FIFO means the session died abnormally. */
 858
 859         session_remove_fifo(s);
 860         session_stop(s, false);
 861
 862         return 1;
 863 }
 864
 865 int session_create_fifo(Session *s) {
 866         int r;
 867
 868         assert(s);
 869
 870         /* Create FIFO */
 871         if (!s->fifo_path) {
 872                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 873                 if (r < 0)
 874                         return r;
 875
 876                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 877                         return -ENOMEM;
 878
 879                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 880                         return -errno;
 881         }
 882
 883         /* Open reading side */
 884         if (s->fifo_fd < 0) {
 885                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 886                 if (s->fifo_fd < 0)
 887                         return -errno;
 888
 889         }
 890
 891         if (!s->fifo_event_source) {
 892                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
 893                 if (r < 0)
 894                         return r;
 895
 896                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_IDLE);
 897                 if (r < 0)
 898                         return r;
 899         }
 900
 901         /* Open writing side */
 902         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 903         if (r < 0)
 904                 return -errno;
 905
 906         return r;
 907 }
 908
 909 static void session_remove_fifo(Session *s) {
 910         assert(s);
 911
 912         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
 913         s->fifo_fd = safe_close(s->fifo_fd);
 914
 915         if (s->fifo_path) {
 916                 unlink(s->fifo_path);
 917                 free(s->fifo_path);
 918                 s->fifo_path = NULL;
 919         }
 920 }
 921
 922 bool session_check_gc(Session *s, bool drop_not_started) {
 923         assert(s);
 924
 925         if (drop_not_started && !s->started)
 926                 return false;
 927
 928         if (!s->user)
 929                 return false;
 930
 931         if (s->fifo_fd >= 0) {
 932                 if (pipe_eof(s->fifo_fd) <= 0)
 933                         return true;
 934         }
 935
 936         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
 937                 return true;
 938
 939         if (s->scope && manager_unit_is_active(s->manager, s->scope))
 940                 return true;
 941
 942         return false;
 943 }
 944
 945 void session_add_to_gc_queue(Session *s) {
 946         assert(s);
 947
 948         if (s->in_gc_queue)
 949                 return;
 950
 951         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
 952         s->in_gc_queue = true;
 953 }
 954
 955 SessionState session_get_state(Session *s) {
 956         assert(s);
 957
 958         /* always check closing first */
 959         if (s->stopping || s->timer_event_source)
 960                 return SESSION_CLOSING;
 961
 962         if (s->scope_job || s->fifo_fd < 0)
 963                 return SESSION_OPENING;
 964
 965         if (session_is_active(s))
 966                 return SESSION_ACTIVE;
 967
 968         return SESSION_ONLINE;
 969 }
 970
 971 int session_kill(Session *s, KillWho who, int signo) {
 972         assert(s);
 973
 974         if (!s->scope)
 975                 return -ESRCH;
 976
 977         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
 978 }
 979
 980 static int session_open_vt(Session *s) {
 981         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
 982
 983         if (s->vtnr < 1)
 984                 return -ENODEV;
 985
 986         if (s->vtfd >= 0)
 987                 return s->vtfd;
 988
 989         sprintf(path, "/dev/tty%u", s->vtnr);
 990         s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
 991         if (s->vtfd < 0)
 992                 return log_error_errno(errno, "cannot open VT %s of session %s: %m", path, s->id);
 993
 994         return s->vtfd;
 995 }
 996
 997 int session_prepare_vt(Session *s) {
 998         int vt, r;
 999         struct vt_mode mode = { 0 };
1000
1001         if (s->vtnr < 1)
1002                 return 0;
1003
1004         vt = session_open_vt(s);
1005         if (vt < 0)
1006                 return vt;
1007
1008         r = fchown(vt, s->user->uid, -1);
1009         if (r < 0) {
1010                 r = -errno;
1011                 log_error_errno(errno, "Cannot change owner of /dev/tty%u: %m", s->vtnr);
1012                 goto error;
1013         }
1014
1015         r = ioctl(vt, KDSKBMODE, K_OFF);
1016         if (r < 0) {
1017                 r = -errno;
1018                 log_error_errno(errno, "Cannot set K_OFF on /dev/tty%u: %m", s->vtnr);
1019                 goto error;
1020         }
1021
1022         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1023         if (r < 0) {
1024                 r = -errno;
1025                 log_error_errno(errno, "Cannot set KD_GRAPHICS on /dev/tty%u: %m", s->vtnr);
1026                 goto error;
1027         }
1028
1029         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1030          * So we need a dummy handler here which just acknowledges *all* VT
1031          * switch requests. */
1032         mode.mode = VT_PROCESS;
1033         mode.relsig = SIGRTMIN;
1034         mode.acqsig = SIGRTMIN + 1;
1035         r = ioctl(vt, VT_SETMODE, &mode);
1036         if (r < 0) {
1037                 r = -errno;
1038                 log_error_errno(errno, "Cannot set VT_PROCESS on /dev/tty%u: %m", s->vtnr);
1039                 goto error;
1040         }
1041
1042         return 0;
1043
1044 error:
1045         session_restore_vt(s);
1046         return r;
1047 }
1048
1049 void session_restore_vt(Session *s) {
1050         _cleanup_free_ char *utf8 = NULL;
1051         int vt, kb = K_XLATE;
1052         struct vt_mode mode = { 0 };
1053
1054         vt = session_open_vt(s);
1055         if (vt < 0)
1056                 return;
1057
1058         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1059
1060         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
1061                 kb = K_UNICODE;
1062
1063         (void) ioctl(vt, KDSKBMODE, kb);
1064
1065         mode.mode = VT_AUTO;
1066         (void) ioctl(vt, VT_SETMODE, &mode);
1067
1068         fchown(vt, 0, -1);
1069
1070         s->vtfd = safe_close(s->vtfd);
1071 }
1072
1073 void session_leave_vt(Session *s) {
1074         int r;
1075
1076         assert(s);
1077
1078         /* This is called whenever we get a VT-switch signal from the kernel.
1079          * We acknowledge all of them unconditionally. Note that session are
1080          * free to overwrite those handlers and we only register them for
1081          * sessions with controllers. Legacy sessions are not affected.
1082          * However, if we switch from a non-legacy to a legacy session, we must
1083          * make sure to pause all device before acknowledging the switch. We
1084          * process the real switch only after we are notified via sysfs, so the
1085          * legacy session might have already started using the devices. If we
1086          * don't pause the devices before the switch, we might confuse the
1087          * session we switch to. */
1088
1089         if (s->vtfd < 0)
1090                 return;
1091
1092         session_device_pause_all(s);
1093         r = ioctl(s->vtfd, VT_RELDISP, 1);
1094         if (r < 0)
1095                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1096 }
1097
1098 bool session_is_controller(Session *s, const char *sender) {
1099         assert(s);
1100
1101         return streq_ptr(s->controller, sender);
1102 }
1103
1104 static void session_release_controller(Session *s, bool notify) {
1105         _cleanup_free_ char *name = NULL;
1106         SessionDevice *sd;
1107
1108         if (!s->controller)
1109                 return;
1110
1111         name = s->controller;
1112
1113         /* By resetting the controller before releasing the devices, we won't
1114          * send notification signals. This avoids sending useless notifications
1115          * if the controller is released on disconnects. */
1116         if (!notify)
1117                 s->controller = NULL;
1118
1119         while ((sd = hashmap_first(s->devices)))
1120                 session_device_free(sd);
1121
1122         s->controller = NULL;
1123         manager_drop_busname(s->manager, name);
1124 }
1125
1126 int session_set_controller(Session *s, const char *sender, bool force) {
1127         _cleanup_free_ char *name = NULL;
1128         int r;
1129
1130         assert(s);
1131         assert(sender);
1132
1133         if (session_is_controller(s, sender))
1134                 return 0;
1135         if (s->controller && !force)
1136                 return -EBUSY;
1137
1138         name = strdup(sender);
1139         if (!name)
1140                 return -ENOMEM;
1141
1142         r = manager_watch_busname(s->manager, name);
1143         if (r)
1144                 return r;
1145
1146         /* When setting a session controller, we forcibly mute the VT and set
1147          * it into graphics-mode. Applications can override that by changing
1148          * VT state after calling TakeControl(). However, this serves as a good
1149          * default and well-behaving controllers can now ignore VTs entirely.
1150          * Note that we reset the VT on ReleaseControl() and if the controller
1151          * exits.
1152          * If logind crashes/restarts, we restore the controller during restart
1153          * or reset the VT in case it crashed/exited, too. */
1154         r = session_prepare_vt(s);
1155         if (r < 0) {
1156                 manager_drop_busname(s->manager, name);
1157                 return r;
1158         }
1159
1160         session_release_controller(s, true);
1161         s->controller = name;
1162         name = NULL;
1163         session_save(s);
1164
1165         return 0;
1166 }
1167
1168 void session_drop_controller(Session *s) {
1169         assert(s);
1170
1171         if (!s->controller)
1172                 return;
1173
1174         session_release_controller(s, false);
1175         session_save(s);
1176         session_restore_vt(s);
1177 }
1178
1179 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1180         [SESSION_OPENING] = "opening",
1181         [SESSION_ONLINE] = "online",
1182         [SESSION_ACTIVE] = "active",
1183         [SESSION_CLOSING] = "closing"
1184 };
1185
1186 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1187
1188 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1189         [SESSION_UNSPECIFIED] = "unspecified",
1190         [SESSION_TTY] = "tty",
1191         [SESSION_X11] = "x11",
1192         [SESSION_WAYLAND] = "wayland",
1193         [SESSION_MIR] = "mir",
1194         [SESSION_WEB] = "web",
1195 };
1196
1197 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1198
1199 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1200         [SESSION_USER] = "user",
1201         [SESSION_GREETER] = "greeter",
1202         [SESSION_LOCK_SCREEN] = "lock-screen",
1203         [SESSION_BACKGROUND] = "background"
1204 };
1205
1206 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1207
1208 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1209         [KILL_LEADER] = "leader",
1210         [KILL_ALL] = "all"
1211 };
1212
1213 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);