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         SessionDevice *sd;
 660
 661         assert(s);
 662
 663         if (!s->user)
 664                 return -ESTALE;
 665
 666         if (s->started)
 667                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 668                            LOG_MESSAGE_ID(SD_MESSAGE_SESSION_STOP),
 669                            "SESSION_ID=%s", s->id,
 670                            "USER_ID=%s", s->user->name,
 671                            "LEADER="PID_FMT, s->leader,
 672                            LOG_MESSAGE("Removed session %s.", s->id),
 673                            NULL);
 674
 675         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 676
 677         if (s->seat)
 678                 seat_evict_position(s->seat, s);
 679
 680         /* Kill session devices */
 681         while ((sd = hashmap_first(s->devices)))
 682                 session_device_free(sd);
 683
 684         (void) unlink(s->state_file);
 685         session_add_to_gc_queue(s);
 686         user_add_to_gc_queue(s->user);
 687
 688         if (s->started) {
 689                 session_send_signal(s, false);
 690                 s->started = false;
 691         }
 692
 693         if (s->seat) {
 694                 if (s->seat->active == s)
 695                         seat_set_active(s->seat, NULL);
 696
 697                 seat_save(s->seat);
 698                 seat_send_changed(s->seat, "Sessions", NULL);
 699         }
 700
 701         user_save(s->user);
 702         user_send_changed(s->user, "Sessions", "Display", NULL);
 703
 704         return 0;
 705 }
 706
 707 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 708         Session *s = userdata;
 709
 710         assert(es);
 711         assert(s);
 712
 713         session_stop(s, false);
 714         return 0;
 715 }
 716
 717 int session_release(Session *s) {
 718         assert(s);
 719
 720         if (!s->started || s->stopping)
 721                 return 0;
 722
 723         if (s->timer_event_source)
 724                 return 0;
 725
 726         return sd_event_add_time(s->manager->event,
 727                                  &s->timer_event_source,
 728                                  CLOCK_MONOTONIC,
 729                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 730                                  release_timeout_callback, s);
 731 }
 732
 733 bool session_is_active(Session *s) {
 734         assert(s);
 735
 736         if (!s->seat)
 737                 return true;
 738
 739         return s->seat->active == s;
 740 }
 741
 742 static int get_tty_atime(const char *tty, usec_t *atime) {
 743         _cleanup_free_ char *p = NULL;
 744         struct stat st;
 745
 746         assert(tty);
 747         assert(atime);
 748
 749         if (!path_is_absolute(tty)) {
 750                 p = strappend("/dev/", tty);
 751                 if (!p)
 752                         return -ENOMEM;
 753
 754                 tty = p;
 755         } else if (!path_startswith(tty, "/dev/"))
 756                 return -ENOENT;
 757
 758         if (lstat(tty, &st) < 0)
 759                 return -errno;
 760
 761         *atime = timespec_load(&st.st_atim);
 762         return 0;
 763 }
 764
 765 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 766         _cleanup_free_ char *p = NULL;
 767         int r;
 768
 769         assert(pid > 0);
 770         assert(atime);
 771
 772         r = get_ctty(pid, NULL, &p);
 773         if (r < 0)
 774                 return r;
 775
 776         return get_tty_atime(p, atime);
 777 }
 778
 779 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 780         usec_t atime = 0, n;
 781         int r;
 782
 783         assert(s);
 784
 785         /* Explicit idle hint is set */
 786         if (s->idle_hint) {
 787                 if (t)
 788                         *t = s->idle_hint_timestamp;
 789
 790                 return s->idle_hint;
 791         }
 792
 793         /* Graphical sessions should really implement a real
 794          * idle hint logic */
 795         if (s->display)
 796                 goto dont_know;
 797
 798         /* For sessions with an explicitly configured tty, let's check
 799          * its atime */
 800         if (s->tty) {
 801                 r = get_tty_atime(s->tty, &atime);
 802                 if (r >= 0)
 803                         goto found_atime;
 804         }
 805
 806         /* For sessions with a leader but no explicitly configured
 807          * tty, let's check the controlling tty of the leader */
 808         if (s->leader > 0) {
 809                 r = get_process_ctty_atime(s->leader, &atime);
 810                 if (r >= 0)
 811                         goto found_atime;
 812         }
 813
 814 dont_know:
 815         if (t)
 816                 *t = s->idle_hint_timestamp;
 817
 818         return 0;
 819
 820 found_atime:
 821         if (t)
 822                 dual_timestamp_from_realtime(t, atime);
 823
 824         n = now(CLOCK_REALTIME);
 825
 826         if (s->manager->idle_action_usec <= 0)
 827                 return 0;
 828
 829         return atime + s->manager->idle_action_usec <= n;
 830 }
 831
 832 void session_set_idle_hint(Session *s, bool b) {
 833         assert(s);
 834
 835         if (s->idle_hint == b)
 836                 return;
 837
 838         s->idle_hint = b;
 839         dual_timestamp_get(&s->idle_hint_timestamp);
 840
 841         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 842
 843         if (s->seat)
 844                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 845
 846         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 847         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 848 }
 849
 850 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 851         Session *s = userdata;
 852
 853         assert(s);
 854         assert(s->fifo_fd == fd);
 855
 856         /* EOF on the FIFO means the session died abnormally. */
 857
 858         session_remove_fifo(s);
 859         session_stop(s, false);
 860
 861         return 1;
 862 }
 863
 864 int session_create_fifo(Session *s) {
 865         int r;
 866
 867         assert(s);
 868
 869         /* Create FIFO */
 870         if (!s->fifo_path) {
 871                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 872                 if (r < 0)
 873                         return r;
 874
 875                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 876                         return -ENOMEM;
 877
 878                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 879                         return -errno;
 880         }
 881
 882         /* Open reading side */
 883         if (s->fifo_fd < 0) {
 884                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 885                 if (s->fifo_fd < 0)
 886                         return -errno;
 887
 888         }
 889
 890         if (!s->fifo_event_source) {
 891                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
 892                 if (r < 0)
 893                         return r;
 894
 895                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_IDLE);
 896                 if (r < 0)
 897                         return r;
 898         }
 899
 900         /* Open writing side */
 901         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 902         if (r < 0)
 903                 return -errno;
 904
 905         return r;
 906 }
 907
 908 static void session_remove_fifo(Session *s) {
 909         assert(s);
 910
 911         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
 912         s->fifo_fd = safe_close(s->fifo_fd);
 913
 914         if (s->fifo_path) {
 915                 unlink(s->fifo_path);
 916                 free(s->fifo_path);
 917                 s->fifo_path = NULL;
 918         }
 919 }
 920
 921 bool session_check_gc(Session *s, bool drop_not_started) {
 922         assert(s);
 923
 924         if (drop_not_started && !s->started)
 925                 return false;
 926
 927         if (!s->user)
 928                 return false;
 929
 930         if (s->fifo_fd >= 0) {
 931                 if (pipe_eof(s->fifo_fd) <= 0)
 932                         return true;
 933         }
 934
 935         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
 936                 return true;
 937
 938         if (s->scope && manager_unit_is_active(s->manager, s->scope))
 939                 return true;
 940
 941         return false;
 942 }
 943
 944 void session_add_to_gc_queue(Session *s) {
 945         assert(s);
 946
 947         if (s->in_gc_queue)
 948                 return;
 949
 950         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
 951         s->in_gc_queue = true;
 952 }
 953
 954 SessionState session_get_state(Session *s) {
 955         assert(s);
 956
 957         /* always check closing first */
 958         if (s->stopping || s->timer_event_source)
 959                 return SESSION_CLOSING;
 960
 961         if (s->scope_job || s->fifo_fd < 0)
 962                 return SESSION_OPENING;
 963
 964         if (session_is_active(s))
 965                 return SESSION_ACTIVE;
 966
 967         return SESSION_ONLINE;
 968 }
 969
 970 int session_kill(Session *s, KillWho who, int signo) {
 971         assert(s);
 972
 973         if (!s->scope)
 974                 return -ESRCH;
 975
 976         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
 977 }
 978
 979 static int session_open_vt(Session *s) {
 980         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
 981
 982         if (s->vtnr < 1)
 983                 return -ENODEV;
 984
 985         if (s->vtfd >= 0)
 986                 return s->vtfd;
 987
 988         sprintf(path, "/dev/tty%u", s->vtnr);
 989         s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
 990         if (s->vtfd < 0)
 991                 return log_error_errno(errno, "cannot open VT %s of session %s: %m", path, s->id);
 992
 993         return s->vtfd;
 994 }
 995
 996 int session_prepare_vt(Session *s) {
 997         int vt, r;
 998         struct vt_mode mode = { 0 };
 999
1000         if (s->vtnr < 1)
1001                 return 0;
1002
1003         vt = session_open_vt(s);
1004         if (vt < 0)
1005                 return vt;
1006
1007         r = fchown(vt, s->user->uid, -1);
1008         if (r < 0) {
1009                 r = -errno;
1010                 log_error_errno(errno, "Cannot change owner of /dev/tty%u: %m", s->vtnr);
1011                 goto error;
1012         }
1013
1014         r = ioctl(vt, KDSKBMODE, K_OFF);
1015         if (r < 0) {
1016                 r = -errno;
1017                 log_error_errno(errno, "Cannot set K_OFF on /dev/tty%u: %m", s->vtnr);
1018                 goto error;
1019         }
1020
1021         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1022         if (r < 0) {
1023                 r = -errno;
1024                 log_error_errno(errno, "Cannot set KD_GRAPHICS on /dev/tty%u: %m", s->vtnr);
1025                 goto error;
1026         }
1027
1028         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1029          * So we need a dummy handler here which just acknowledges *all* VT
1030          * switch requests. */
1031         mode.mode = VT_PROCESS;
1032         mode.relsig = SIGRTMIN;
1033         mode.acqsig = SIGRTMIN + 1;
1034         r = ioctl(vt, VT_SETMODE, &mode);
1035         if (r < 0) {
1036                 r = -errno;
1037                 log_error_errno(errno, "Cannot set VT_PROCESS on /dev/tty%u: %m", s->vtnr);
1038                 goto error;
1039         }
1040
1041         return 0;
1042
1043 error:
1044         session_restore_vt(s);
1045         return r;
1046 }
1047
1048 void session_restore_vt(Session *s) {
1049         _cleanup_free_ char *utf8 = NULL;
1050         int vt, kb = K_XLATE;
1051         struct vt_mode mode = { 0 };
1052
1053         vt = session_open_vt(s);
1054         if (vt < 0)
1055                 return;
1056
1057         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1058
1059         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
1060                 kb = K_UNICODE;
1061
1062         (void) ioctl(vt, KDSKBMODE, kb);
1063
1064         mode.mode = VT_AUTO;
1065         (void) ioctl(vt, VT_SETMODE, &mode);
1066
1067         fchown(vt, 0, -1);
1068
1069         s->vtfd = safe_close(s->vtfd);
1070 }
1071
1072 void session_leave_vt(Session *s) {
1073         int r;
1074
1075         assert(s);
1076
1077         /* This is called whenever we get a VT-switch signal from the kernel.
1078          * We acknowledge all of them unconditionally. Note that session are
1079          * free to overwrite those handlers and we only register them for
1080          * sessions with controllers. Legacy sessions are not affected.
1081          * However, if we switch from a non-legacy to a legacy session, we must
1082          * make sure to pause all device before acknowledging the switch. We
1083          * process the real switch only after we are notified via sysfs, so the
1084          * legacy session might have already started using the devices. If we
1085          * don't pause the devices before the switch, we might confuse the
1086          * session we switch to. */
1087
1088         if (s->vtfd < 0)
1089                 return;
1090
1091         session_device_pause_all(s);
1092         r = ioctl(s->vtfd, VT_RELDISP, 1);
1093         if (r < 0)
1094                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1095 }
1096
1097 bool session_is_controller(Session *s, const char *sender) {
1098         assert(s);
1099
1100         return streq_ptr(s->controller, sender);
1101 }
1102
1103 static void session_release_controller(Session *s, bool notify) {
1104         _cleanup_free_ char *name = NULL;
1105         SessionDevice *sd;
1106
1107         if (!s->controller)
1108                 return;
1109
1110         name = s->controller;
1111
1112         /* By resetting the controller before releasing the devices, we won't
1113          * send notification signals. This avoids sending useless notifications
1114          * if the controller is released on disconnects. */
1115         if (!notify)
1116                 s->controller = NULL;
1117
1118         while ((sd = hashmap_first(s->devices)))
1119                 session_device_free(sd);
1120
1121         s->controller = NULL;
1122         s->track = sd_bus_track_unref(s->track);
1123 }
1124
1125 static int on_bus_track(sd_bus_track *track, void *userdata) {
1126         Session *s = userdata;
1127
1128         assert(track);
1129         assert(s);
1130
1131         session_drop_controller(s);
1132
1133         return 0;
1134 }
1135
1136 int session_set_controller(Session *s, const char *sender, bool force) {
1137         _cleanup_free_ char *name = NULL;
1138         int r;
1139
1140         assert(s);
1141         assert(sender);
1142
1143         if (session_is_controller(s, sender))
1144                 return 0;
1145         if (s->controller && !force)
1146                 return -EBUSY;
1147
1148         name = strdup(sender);
1149         if (!name)
1150                 return -ENOMEM;
1151
1152         s->track = sd_bus_track_unref(s->track);
1153         r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
1154         if (r < 0)
1155                 return r;
1156
1157         r = sd_bus_track_add_name(s->track, name);
1158         if (r < 0)
1159                 return r;
1160
1161         /* When setting a session controller, we forcibly mute the VT and set
1162          * it into graphics-mode. Applications can override that by changing
1163          * VT state after calling TakeControl(). However, this serves as a good
1164          * default and well-behaving controllers can now ignore VTs entirely.
1165          * Note that we reset the VT on ReleaseControl() and if the controller
1166          * exits.
1167          * If logind crashes/restarts, we restore the controller during restart
1168          * or reset the VT in case it crashed/exited, too. */
1169         r = session_prepare_vt(s);
1170         if (r < 0) {
1171                 s->track = sd_bus_track_unref(s->track);
1172                 return r;
1173         }
1174
1175         session_release_controller(s, true);
1176         s->controller = name;
1177         name = NULL;
1178         session_save(s);
1179
1180         return 0;
1181 }
1182
1183 void session_drop_controller(Session *s) {
1184         assert(s);
1185
1186         if (!s->controller)
1187                 return;
1188
1189         s->track = sd_bus_track_unref(s->track);
1190         session_release_controller(s, false);
1191         session_save(s);
1192         session_restore_vt(s);
1193 }
1194
1195 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1196         [SESSION_OPENING] = "opening",
1197         [SESSION_ONLINE] = "online",
1198         [SESSION_ACTIVE] = "active",
1199         [SESSION_CLOSING] = "closing"
1200 };
1201
1202 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1203
1204 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1205         [SESSION_UNSPECIFIED] = "unspecified",
1206         [SESSION_TTY] = "tty",
1207         [SESSION_X11] = "x11",
1208         [SESSION_WAYLAND] = "wayland",
1209         [SESSION_MIR] = "mir",
1210         [SESSION_WEB] = "web",
1211 };
1212
1213 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1214
1215 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1216         [SESSION_USER] = "user",
1217         [SESSION_GREETER] = "greeter",
1218         [SESSION_LOCK_SCREEN] = "lock-screen",
1219         [SESSION_BACKGROUND] = "background"
1220 };
1221
1222 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1223
1224 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1225         [KILL_LEADER] = "leader",
1226         [KILL_ALL] = "all"
1227 };
1228
1229 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);