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-id128.h"
  32 #include "sd-messages.h"
  33 #include "strv.h"
  34 #include "util.h"
  35 #include "mkdir.h"
  36 #include "path-util.h"
  37 #include "fileio.h"
  38 #include "audit.h"
  39 #include "bus-util.h"
  40 #include "bus-error.h"
  41 #include "logind-session.h"
  42
  43 #define RELEASE_USEC (20*USEC_PER_SEC)
  44
  45 static void session_remove_fifo(Session *s);
  46
  47 static unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
  48         uint64_t u = *(const dev_t*)p;
  49
  50         return uint64_hash_func(&u, hash_key);
  51 }
  52
  53 static int devt_compare_func(const void *_a, const void *_b) {
  54         dev_t a, b;
  55
  56         a = *(const dev_t*) _a;
  57         b = *(const dev_t*) _b;
  58
  59         return a < b ? -1 : (a > b ? 1 : 0);
  60 }
  61
  62 Session* session_new(Manager *m, const char *id) {
  63         Session *s;
  64
  65         assert(m);
  66         assert(id);
  67         assert(session_id_valid(id));
  68
  69         s = new0(Session, 1);
  70         if (!s)
  71                 return NULL;
  72
  73         s->state_file = strappend("/run/systemd/sessions/", id);
  74         if (!s->state_file) {
  75                 free(s);
  76                 return NULL;
  77         }
  78
  79         s->devices = hashmap_new(devt_hash_func, devt_compare_func);
  80         if (!s->devices) {
  81                 free(s->state_file);
  82                 free(s);
  83                 return NULL;
  84         }
  85
  86         s->id = basename(s->state_file);
  87
  88         if (hashmap_put(m->sessions, s->id, s) < 0) {
  89                 hashmap_free(s->devices);
  90                 free(s->state_file);
  91                 free(s);
  92                 return NULL;
  93         }
  94
  95         s->manager = m;
  96         s->fifo_fd = -1;
  97         s->vtfd = -1;
  98
  99         return s;
 100 }
 101
 102 void session_free(Session *s) {
 103         SessionDevice *sd;
 104
 105         assert(s);
 106
 107         if (s->in_gc_queue)
 108                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
 109
 110         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 111
 112         session_remove_fifo(s);
 113
 114         session_drop_controller(s);
 115
 116         while ((sd = hashmap_first(s->devices)))
 117                 session_device_free(sd);
 118
 119         hashmap_free(s->devices);
 120
 121         if (s->user) {
 122                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 123
 124                 if (s->user->display == s)
 125                         s->user->display = NULL;
 126         }
 127
 128         if (s->seat) {
 129                 if (s->seat->active == s)
 130                         s->seat->active = NULL;
 131                 if (s->seat->pending_switch == s)
 132                         s->seat->pending_switch = NULL;
 133
 134                 seat_evict_position(s->seat, s);
 135                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 136         }
 137
 138         if (s->scope) {
 139                 hashmap_remove(s->manager->session_units, s->scope);
 140                 free(s->scope);
 141         }
 142
 143         free(s->scope_job);
 144
 145         sd_bus_message_unref(s->create_message);
 146
 147         free(s->tty);
 148         free(s->display);
 149         free(s->remote_host);
 150         free(s->remote_user);
 151         free(s->service);
 152         free(s->desktop);
 153
 154         hashmap_remove(s->manager->sessions, s->id);
 155
 156         free(s->state_file);
 157         free(s);
 158 }
 159
 160 void session_set_user(Session *s, User *u) {
 161         assert(s);
 162         assert(!s->user);
 163
 164         s->user = u;
 165         LIST_PREPEND(sessions_by_user, u->sessions, s);
 166 }
 167
 168 int session_save(Session *s) {
 169         _cleanup_free_ char *temp_path = NULL;
 170         _cleanup_fclose_ FILE *f = NULL;
 171         int r = 0;
 172
 173         assert(s);
 174
 175         if (!s->user)
 176                 return -ESTALE;
 177
 178         if (!s->started)
 179                 return 0;
 180
 181         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 182         if (r < 0)
 183                 goto finish;
 184
 185         r = fopen_temporary(s->state_file, &f, &temp_path);
 186         if (r < 0)
 187                 goto finish;
 188
 189         assert(s->user);
 190
 191         fchmod(fileno(f), 0644);
 192
 193         fprintf(f,
 194                 "# This is private data. Do not parse.\n"
 195                 "UID="UID_FMT"\n"
 196                 "USER=%s\n"
 197                 "ACTIVE=%i\n"
 198                 "STATE=%s\n"
 199                 "REMOTE=%i\n",
 200                 s->user->uid,
 201                 s->user->name,
 202                 session_is_active(s),
 203                 session_state_to_string(session_get_state(s)),
 204                 s->remote);
 205
 206         if (s->type >= 0)
 207                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 208
 209         if (s->class >= 0)
 210                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 211
 212         if (s->scope)
 213                 fprintf(f, "SCOPE=%s\n", s->scope);
 214         if (s->scope_job)
 215                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 216
 217         if (s->fifo_path)
 218                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 219
 220         if (s->seat)
 221                 fprintf(f, "SEAT=%s\n", s->seat->id);
 222
 223         if (s->tty)
 224                 fprintf(f, "TTY=%s\n", s->tty);
 225
 226         if (s->display)
 227                 fprintf(f, "DISPLAY=%s\n", s->display);
 228
 229         if (s->remote_host) {
 230                 _cleanup_free_ char *escaped;
 231
 232                 escaped = cescape(s->remote_host);
 233                 if (!escaped) {
 234                         r = -ENOMEM;
 235                         goto finish;
 236                 }
 237
 238                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 239         }
 240
 241         if (s->remote_user) {
 242                 _cleanup_free_ char *escaped;
 243
 244                 escaped = cescape(s->remote_user);
 245                 if (!escaped) {
 246                         r = -ENOMEM;
 247                         goto finish;
 248                 }
 249
 250                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 251         }
 252
 253         if (s->service) {
 254                 _cleanup_free_ char *escaped;
 255
 256                 escaped = cescape(s->service);
 257                 if (!escaped) {
 258                         r = -ENOMEM;
 259                         goto finish;
 260                 }
 261
 262                 fprintf(f, "SERVICE=%s\n", escaped);
 263         }
 264
 265         if (s->desktop) {
 266                 _cleanup_free_ char *escaped;
 267
 268
 269                 escaped = cescape(s->desktop);
 270                 if (!escaped) {
 271                         r = -ENOMEM;
 272                         goto finish;
 273                 }
 274
 275                 fprintf(f, "DESKTOP=%s\n", escaped);
 276         }
 277
 278         if (s->seat && seat_has_vts(s->seat))
 279                 fprintf(f, "VTNR=%u\n", s->vtnr);
 280
 281         if (!s->vtnr)
 282                 fprintf(f, "POS=%u\n", s->pos);
 283
 284         if (s->leader > 0)
 285                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 286
 287         if (s->audit_id > 0)
 288                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 289
 290         if (dual_timestamp_is_set(&s->timestamp))
 291                 fprintf(f,
 292                         "REALTIME="USEC_FMT"\n"
 293                         "MONOTONIC="USEC_FMT"\n",
 294                         s->timestamp.realtime,
 295                         s->timestamp.monotonic);
 296
 297         if (s->controller)
 298                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 299
 300         fflush(f);
 301
 302         if (ferror(f) || rename(temp_path, s->state_file) < 0) {
 303                 r = -errno;
 304                 unlink(s->state_file);
 305                 unlink(temp_path);
 306         }
 307
 308 finish:
 309         if (r < 0)
 310                 log_error("Failed to save session data %s: %s", s->state_file, strerror(-r));
 311
 312         return r;
 313 }
 314
 315 int session_load(Session *s) {
 316         _cleanup_free_ char *remote = NULL,
 317                 *seat = NULL,
 318                 *vtnr = NULL,
 319                 *pos = NULL,
 320                 *leader = NULL,
 321                 *type = NULL,
 322                 *class = NULL,
 323                 *uid = NULL,
 324                 *realtime = NULL,
 325                 *monotonic = NULL,
 326                 *controller = NULL;
 327
 328         int k, r;
 329
 330         assert(s);
 331
 332         r = parse_env_file(s->state_file, NEWLINE,
 333                            "REMOTE",         &remote,
 334                            "SCOPE",          &s->scope,
 335                            "SCOPE_JOB",      &s->scope_job,
 336                            "FIFO",           &s->fifo_path,
 337                            "SEAT",           &seat,
 338                            "TTY",            &s->tty,
 339                            "DISPLAY",        &s->display,
 340                            "REMOTE_HOST",    &s->remote_host,
 341                            "REMOTE_USER",    &s->remote_user,
 342                            "SERVICE",        &s->service,
 343                            "DESKTOP",        &s->desktop,
 344                            "VTNR",           &vtnr,
 345                            "POS",            &pos,
 346                            "LEADER",         &leader,
 347                            "TYPE",           &type,
 348                            "CLASS",          &class,
 349                            "UID",            &uid,
 350                            "REALTIME",       &realtime,
 351                            "MONOTONIC",      &monotonic,
 352                            "CONTROLLER",     &controller,
 353                            NULL);
 354
 355         if (r < 0) {
 356                 log_error("Failed to read %s: %s", s->state_file, strerror(-r));
 357                 return r;
 358         }
 359
 360         if (!s->user) {
 361                 uid_t u;
 362                 User *user;
 363
 364                 if (!uid) {
 365                         log_error("UID not specified for session %s", s->id);
 366                         return -ENOENT;
 367                 }
 368
 369                 r = parse_uid(uid, &u);
 370                 if (r < 0)  {
 371                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 372                         return r;
 373                 }
 374
 375                 user = hashmap_get(s->manager->users, ULONG_TO_PTR((unsigned long) u));
 376                 if (!user) {
 377                         log_error("User of session %s not known.", s->id);
 378                         return -ENOENT;
 379                 }
 380
 381                 session_set_user(s, user);
 382         }
 383
 384         if (remote) {
 385                 k = parse_boolean(remote);
 386                 if (k >= 0)
 387                         s->remote = k;
 388         }
 389
 390         if (vtnr)
 391                 safe_atou(vtnr, &s->vtnr);
 392
 393         if (seat && !s->seat) {
 394                 Seat *o;
 395
 396                 o = hashmap_get(s->manager->seats, seat);
 397                 if (o)
 398                         r = seat_attach_session(o, s);
 399                 if (!o || r < 0)
 400                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 401         }
 402
 403         if (!s->seat || !seat_has_vts(s->seat))
 404                 s->vtnr = 0;
 405
 406         if (pos && s->seat) {
 407                 unsigned int npos;
 408
 409                 safe_atou(pos, &npos);
 410                 seat_claim_position(s->seat, s, npos);
 411         }
 412
 413         if (leader) {
 414                 k = parse_pid(leader, &s->leader);
 415                 if (k >= 0)
 416                         audit_session_from_pid(s->leader, &s->audit_id);
 417         }
 418
 419         if (type) {
 420                 SessionType t;
 421
 422                 t = session_type_from_string(type);
 423                 if (t >= 0)
 424                         s->type = t;
 425         }
 426
 427         if (class) {
 428                 SessionClass c;
 429
 430                 c = session_class_from_string(class);
 431                 if (c >= 0)
 432                         s->class = c;
 433         }
 434
 435         if (s->fifo_path) {
 436                 int fd;
 437
 438                 /* If we open an unopened pipe for reading we will not
 439                    get an EOF. to trigger an EOF we hence open it for
 440                    reading, but close it right-away which then will
 441                    trigger the EOF. */
 442
 443                 fd = session_create_fifo(s);
 444                 safe_close(fd);
 445         }
 446
 447         if (realtime) {
 448                 unsigned long long l;
 449                 if (sscanf(realtime, "%llu", &l) > 0)
 450                         s->timestamp.realtime = l;
 451         }
 452
 453         if (monotonic) {
 454                 unsigned long long l;
 455                 if (sscanf(monotonic, "%llu", &l) > 0)
 456                         s->timestamp.monotonic = l;
 457         }
 458
 459         if (controller) {
 460                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
 461                         session_set_controller(s, controller, false);
 462                 else
 463                         session_restore_vt(s);
 464         }
 465
 466         return r;
 467 }
 468
 469 int session_activate(Session *s) {
 470         unsigned int num_pending;
 471
 472         assert(s);
 473         assert(s->user);
 474
 475         if (!s->seat)
 476                 return -ENOTSUP;
 477
 478         if (s->seat->active == s)
 479                 return 0;
 480
 481         /* on seats with VTs, we let VTs manage session-switching */
 482         if (seat_has_vts(s->seat)) {
 483                 if (!s->vtnr)
 484                         return -ENOTSUP;
 485
 486                 return chvt(s->vtnr);
 487         }
 488
 489         /* On seats without VTs, we implement session-switching in logind. We
 490          * try to pause all session-devices and wait until the session
 491          * controller acknowledged them. Once all devices are asleep, we simply
 492          * switch the active session and be done.
 493          * We save the session we want to switch to in seat->pending_switch and
 494          * seat_complete_switch() will perform the final switch. */
 495
 496         s->seat->pending_switch = s;
 497
 498         /* if no devices are running, immediately perform the session switch */
 499         num_pending = session_device_try_pause_all(s);
 500         if (!num_pending)
 501                 seat_complete_switch(s->seat);
 502
 503         return 0;
 504 }
 505
 506 static int session_start_scope(Session *s) {
 507         int r;
 508
 509         assert(s);
 510         assert(s->user);
 511         assert(s->user->slice);
 512
 513         if (!s->scope) {
 514                 _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 515                 _cleanup_free_ char *description = NULL;
 516                 char *scope, *job = NULL;
 517
 518                 description = strjoin("Session ", s->id, " of user ", s->user->name, NULL);
 519                 if (!description)
 520                         return log_oom();
 521
 522                 scope = strjoin("session-", s->id, ".scope", NULL);
 523                 if (!scope)
 524                         return log_oom();
 525
 526                 r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-logind.service", "systemd-user-sessions.service", &error, &job);
 527                 if (r < 0) {
 528                         log_error("Failed to start session scope %s: %s %s",
 529                                   scope, bus_error_message(&error, r), error.name);
 530                         free(scope);
 531                         return r;
 532                 } else {
 533                         s->scope = scope;
 534
 535                         free(s->scope_job);
 536                         s->scope_job = job;
 537                 }
 538         }
 539
 540         if (s->scope)
 541                 hashmap_put(s->manager->session_units, s->scope, s);
 542
 543         return 0;
 544 }
 545
 546 int session_start(Session *s) {
 547         int r;
 548
 549         assert(s);
 550
 551         if (!s->user)
 552                 return -ESTALE;
 553
 554         if (s->started)
 555                 return 0;
 556
 557         r = user_start(s->user);
 558         if (r < 0)
 559                 return r;
 560
 561         /* Create cgroup */
 562         r = session_start_scope(s);
 563         if (r < 0)
 564                 return r;
 565
 566         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 567                    MESSAGE_ID(SD_MESSAGE_SESSION_START),
 568                    "SESSION_ID=%s", s->id,
 569                    "USER_ID=%s", s->user->name,
 570                    "LEADER="PID_FMT, s->leader,
 571                    "MESSAGE=New session %s of user %s.", s->id, s->user->name,
 572                    NULL);
 573
 574         if (!dual_timestamp_is_set(&s->timestamp))
 575                 dual_timestamp_get(&s->timestamp);
 576
 577         if (s->seat)
 578                 seat_read_active_vt(s->seat);
 579
 580         s->started = true;
 581
 582         user_elect_display(s->user);
 583
 584         /* Save data */
 585         session_save(s);
 586         user_save(s->user);
 587         if (s->seat)
 588                 seat_save(s->seat);
 589
 590         /* Send signals */
 591         session_send_signal(s, true);
 592         user_send_changed(s->user, "Sessions", "Display", NULL);
 593         if (s->seat) {
 594                 if (s->seat->active == s)
 595                         seat_send_changed(s->seat, "Sessions", "ActiveSession", NULL);
 596                 else
 597                         seat_send_changed(s->seat, "Sessions", NULL);
 598         }
 599
 600         return 0;
 601 }
 602
 603 static int session_stop_scope(Session *s, bool force) {
 604         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 605         char *job = NULL;
 606         int r;
 607
 608         assert(s);
 609
 610         if (!s->scope)
 611                 return 0;
 612
 613         if (force || manager_shall_kill(s->manager, s->user->name)) {
 614                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 615                 if (r < 0) {
 616                         log_error("Failed to stop session scope: %s", bus_error_message(&error, r));
 617                         return r;
 618                 }
 619
 620                 free(s->scope_job);
 621                 s->scope_job = job;
 622         } else {
 623                 r = manager_abandon_scope(s->manager, s->scope, &error);
 624                 if (r < 0) {
 625                         log_error("Failed to abandon session scope: %s", bus_error_message(&error, r));
 626                         return r;
 627                 }
 628         }
 629
 630         return 0;
 631 }
 632
 633 int session_stop(Session *s, bool force) {
 634         int r;
 635
 636         assert(s);
 637
 638         if (!s->user)
 639                 return -ESTALE;
 640
 641         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 642
 643         /* We are going down, don't care about FIFOs anymore */
 644         session_remove_fifo(s);
 645
 646         /* Kill cgroup */
 647         r = session_stop_scope(s, force);
 648
 649         s->stopping = true;
 650
 651         user_elect_display(s->user);
 652
 653         session_save(s);
 654         user_save(s->user);
 655
 656         return r;
 657 }
 658
 659 int session_finalize(Session *s) {
 660         int r = 0;
 661         SessionDevice *sd;
 662
 663         assert(s);
 664
 665         if (!s->user)
 666                 return -ESTALE;
 667
 668         if (s->started)
 669                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 670                            MESSAGE_ID(SD_MESSAGE_SESSION_STOP),
 671                            "SESSION_ID=%s", s->id,
 672                            "USER_ID=%s", s->user->name,
 673                            "LEADER="PID_FMT, s->leader,
 674                            "MESSAGE=Removed session %s.", s->id,
 675                            NULL);
 676
 677         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 678
 679         /* Kill session devices */
 680         while ((sd = hashmap_first(s->devices)))
 681                 session_device_free(sd);
 682
 683         unlink(s->state_file);
 684         session_add_to_gc_queue(s);
 685         user_add_to_gc_queue(s->user);
 686
 687         if (s->started) {
 688                 session_send_signal(s, false);
 689                 s->started = false;
 690         }
 691
 692         if (s->seat) {
 693                 if (s->seat->active == s)
 694                         seat_set_active(s->seat, NULL);
 695
 696                 seat_save(s->seat);
 697                 seat_send_changed(s->seat, "Sessions", NULL);
 698         }
 699
 700         user_save(s->user);
 701         user_send_changed(s->user, "Sessions", "Display", NULL);
 702
 703         return r;
 704 }
 705
 706 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 707         Session *s = userdata;
 708
 709         assert(es);
 710         assert(s);
 711
 712         session_stop(s, false);
 713         return 0;
 714 }
 715
 716 void session_release(Session *s) {
 717         assert(s);
 718
 719         if (!s->started || s->stopping)
 720                 return;
 721
 722         if (!s->timer_event_source)
 723                 sd_event_add_time(s->manager->event,
 724                                   &s->timer_event_source,
 725                                   CLOCK_MONOTONIC,
 726                                   now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 727                                   release_timeout_callback, s);
 728 }
 729
 730 bool session_is_active(Session *s) {
 731         assert(s);
 732
 733         if (!s->seat)
 734                 return true;
 735
 736         return s->seat->active == s;
 737 }
 738
 739 static int get_tty_atime(const char *tty, usec_t *atime) {
 740         _cleanup_free_ char *p = NULL;
 741         struct stat st;
 742
 743         assert(tty);
 744         assert(atime);
 745
 746         if (!path_is_absolute(tty)) {
 747                 p = strappend("/dev/", tty);
 748                 if (!p)
 749                         return -ENOMEM;
 750
 751                 tty = p;
 752         } else if (!path_startswith(tty, "/dev/"))
 753                 return -ENOENT;
 754
 755         if (lstat(tty, &st) < 0)
 756                 return -errno;
 757
 758         *atime = timespec_load(&st.st_atim);
 759         return 0;
 760 }
 761
 762 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 763         _cleanup_free_ char *p = NULL;
 764         int r;
 765
 766         assert(pid > 0);
 767         assert(atime);
 768
 769         r = get_ctty(pid, NULL, &p);
 770         if (r < 0)
 771                 return r;
 772
 773         return get_tty_atime(p, atime);
 774 }
 775
 776 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 777         usec_t atime = 0, n;
 778         int r;
 779
 780         assert(s);
 781
 782         /* Explicit idle hint is set */
 783         if (s->idle_hint) {
 784                 if (t)
 785                         *t = s->idle_hint_timestamp;
 786
 787                 return s->idle_hint;
 788         }
 789
 790         /* Graphical sessions should really implement a real
 791          * idle hint logic */
 792         if (s->display)
 793                 goto dont_know;
 794
 795         /* For sessions with an explicitly configured tty, let's check
 796          * its atime */
 797         if (s->tty) {
 798                 r = get_tty_atime(s->tty, &atime);
 799                 if (r >= 0)
 800                         goto found_atime;
 801         }
 802
 803         /* For sessions with a leader but no explicitly configured
 804          * tty, let's check the controlling tty of the leader */
 805         if (s->leader > 0) {
 806                 r = get_process_ctty_atime(s->leader, &atime);
 807                 if (r >= 0)
 808                         goto found_atime;
 809         }
 810
 811 dont_know:
 812         if (t)
 813                 *t = s->idle_hint_timestamp;
 814
 815         return 0;
 816
 817 found_atime:
 818         if (t)
 819                 dual_timestamp_from_realtime(t, atime);
 820
 821         n = now(CLOCK_REALTIME);
 822
 823         if (s->manager->idle_action_usec <= 0)
 824                 return 0;
 825
 826         return atime + s->manager->idle_action_usec <= n;
 827 }
 828
 829 void session_set_idle_hint(Session *s, bool b) {
 830         assert(s);
 831
 832         if (s->idle_hint == b)
 833                 return;
 834
 835         s->idle_hint = b;
 836         dual_timestamp_get(&s->idle_hint_timestamp);
 837
 838         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 839
 840         if (s->seat)
 841                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 842
 843         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 844         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 845 }
 846
 847 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 848         Session *s = userdata;
 849
 850         assert(s);
 851         assert(s->fifo_fd == fd);
 852
 853         /* EOF on the FIFO means the session died abnormally. */
 854
 855         session_remove_fifo(s);
 856         session_stop(s, false);
 857
 858         return 1;
 859 }
 860
 861 int session_create_fifo(Session *s) {
 862         int r;
 863
 864         assert(s);
 865
 866         /* Create FIFO */
 867         if (!s->fifo_path) {
 868                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 869                 if (r < 0)
 870                         return r;
 871
 872                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 873                         return -ENOMEM;
 874
 875                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 876                         return -errno;
 877         }
 878
 879         /* Open reading side */
 880         if (s->fifo_fd < 0) {
 881                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 882                 if (s->fifo_fd < 0)
 883                         return -errno;
 884
 885         }
 886
 887         if (!s->fifo_event_source) {
 888                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
 889                 if (r < 0)
 890                         return r;
 891
 892                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_IDLE);
 893                 if (r < 0)
 894                         return r;
 895         }
 896
 897         /* Open writing side */
 898         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 899         if (r < 0)
 900                 return -errno;
 901
 902         return r;
 903 }
 904
 905 static void session_remove_fifo(Session *s) {
 906         assert(s);
 907
 908         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
 909         s->fifo_fd = safe_close(s->fifo_fd);
 910
 911         if (s->fifo_path) {
 912                 unlink(s->fifo_path);
 913                 free(s->fifo_path);
 914                 s->fifo_path = NULL;
 915         }
 916 }
 917
 918 bool session_check_gc(Session *s, bool drop_not_started) {
 919         assert(s);
 920
 921         if (drop_not_started && !s->started)
 922                 return false;
 923
 924         if (!s->user)
 925                 return false;
 926
 927         if (s->fifo_fd >= 0) {
 928                 if (pipe_eof(s->fifo_fd) <= 0)
 929                         return true;
 930         }
 931
 932         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
 933                 return true;
 934
 935         if (s->scope && manager_unit_is_active(s->manager, s->scope))
 936                 return true;
 937
 938         return false;
 939 }
 940
 941 void session_add_to_gc_queue(Session *s) {
 942         assert(s);
 943
 944         if (s->in_gc_queue)
 945                 return;
 946
 947         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
 948         s->in_gc_queue = true;
 949 }
 950
 951 SessionState session_get_state(Session *s) {
 952         assert(s);
 953
 954         /* always check closing first */
 955         if (s->stopping || s->timer_event_source)
 956                 return SESSION_CLOSING;
 957
 958         if (s->scope_job || s->fifo_fd < 0)
 959                 return SESSION_OPENING;
 960
 961         if (session_is_active(s))
 962                 return SESSION_ACTIVE;
 963
 964         return SESSION_ONLINE;
 965 }
 966
 967 int session_kill(Session *s, KillWho who, int signo) {
 968         assert(s);
 969
 970         if (!s->scope)
 971                 return -ESRCH;
 972
 973         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
 974 }
 975
 976 static int session_open_vt(Session *s) {
 977         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
 978
 979         if (s->vtnr < 1)
 980                 return -ENODEV;
 981
 982         if (s->vtfd >= 0)
 983                 return s->vtfd;
 984
 985         sprintf(path, "/dev/tty%u", s->vtnr);
 986         s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
 987         if (s->vtfd < 0) {
 988                 log_error("cannot open VT %s of session %s: %m", path, s->id);
 989                 return -errno;
 990         }
 991
 992         return s->vtfd;
 993 }
 994
 995 int session_prepare_vt(Session *s) {
 996         int vt, r;
 997         struct vt_mode mode = { 0 };
 998
 999         if (s->vtnr < 1)
1000                 return 0;
1001
1002         vt = session_open_vt(s);
1003         if (vt < 0)
1004                 return vt;
1005
1006         r = fchown(vt, s->user->uid, -1);
1007         if (r < 0) {
1008                 r = -errno;
1009                 log_error("Cannot change owner of /dev/tty%u: %m", s->vtnr);
1010                 goto error;
1011         }
1012
1013         r = ioctl(vt, KDSKBMODE, K_OFF);
1014         if (r < 0) {
1015                 r = -errno;
1016                 log_error("Cannot set K_OFF on /dev/tty%u: %m", s->vtnr);
1017                 goto error;
1018         }
1019
1020         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1021         if (r < 0) {
1022                 r = -errno;
1023                 log_error("Cannot set KD_GRAPHICS on /dev/tty%u: %m", s->vtnr);
1024                 goto error;
1025         }
1026
1027         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1028          * So we need a dummy handler here which just acknowledges *all* VT
1029          * switch requests. */
1030         mode.mode = VT_PROCESS;
1031         mode.relsig = SIGRTMIN;
1032         mode.acqsig = SIGRTMIN + 1;
1033         r = ioctl(vt, VT_SETMODE, &mode);
1034         if (r < 0) {
1035                 r = -errno;
1036                 log_error("Cannot set VT_PROCESS on /dev/tty%u: %m", s->vtnr);
1037                 goto error;
1038         }
1039
1040         return 0;
1041
1042 error:
1043         session_restore_vt(s);
1044         return r;
1045 }
1046
1047 void session_restore_vt(Session *s) {
1048         _cleanup_free_ char *utf8 = NULL;
1049         int vt, kb = K_XLATE;
1050         struct vt_mode mode = { 0 };
1051
1052         vt = session_open_vt(s);
1053         if (vt < 0)
1054                 return;
1055
1056         ioctl(vt, KDSETMODE, KD_TEXT);
1057
1058         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
1059                 kb = K_UNICODE;
1060
1061         ioctl(vt, KDSKBMODE, kb);
1062
1063         mode.mode = VT_AUTO;
1064         ioctl(vt, VT_SETMODE, &mode);
1065
1066         fchown(vt, 0, -1);
1067
1068         s->vtfd = safe_close(s->vtfd);
1069 }
1070
1071 bool session_is_controller(Session *s, const char *sender) {
1072         assert(s);
1073
1074         return streq_ptr(s->controller, sender);
1075 }
1076
1077 static void session_swap_controller(Session *s, char *name) {
1078         SessionDevice *sd;
1079
1080         if (s->controller) {
1081                 manager_drop_busname(s->manager, s->controller);
1082                 free(s->controller);
1083                 s->controller = NULL;
1084
1085                 /* Drop all devices as they're now unused. Do that after the
1086                  * controller is released to avoid sending out useles
1087                  * dbus signals. */
1088                 while ((sd = hashmap_first(s->devices)))
1089                         session_device_free(sd);
1090
1091                 if (!name)
1092                         session_restore_vt(s);
1093         }
1094
1095         s->controller = name;
1096         session_save(s);
1097 }
1098
1099 int session_set_controller(Session *s, const char *sender, bool force) {
1100         char *t;
1101         int r;
1102
1103         assert(s);
1104         assert(sender);
1105
1106         if (session_is_controller(s, sender))
1107                 return 0;
1108         if (s->controller && !force)
1109                 return -EBUSY;
1110
1111         t = strdup(sender);
1112         if (!t)
1113                 return -ENOMEM;
1114
1115         r = manager_watch_busname(s->manager, sender);
1116         if (r) {
1117                 free(t);
1118                 return r;
1119         }
1120
1121         /* When setting a session controller, we forcibly mute the VT and set
1122          * it into graphics-mode. Applications can override that by changing
1123          * VT state after calling TakeControl(). However, this serves as a good
1124          * default and well-behaving controllers can now ignore VTs entirely.
1125          * Note that we reset the VT on ReleaseControl() and if the controller
1126          * exits.
1127          * If logind crashes/restarts, we restore the controller during restart
1128          * or reset the VT in case it crashed/exited, too. */
1129         r = session_prepare_vt(s);
1130         if (r < 0)
1131                 return r;
1132
1133         session_swap_controller(s, t);
1134
1135         return 0;
1136 }
1137
1138 void session_drop_controller(Session *s) {
1139         assert(s);
1140
1141         if (!s->controller)
1142                 return;
1143
1144         session_swap_controller(s, NULL);
1145 }
1146
1147 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1148         [SESSION_OPENING] = "opening",
1149         [SESSION_ONLINE] = "online",
1150         [SESSION_ACTIVE] = "active",
1151         [SESSION_CLOSING] = "closing"
1152 };
1153
1154 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1155
1156 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1157         [SESSION_UNSPECIFIED] = "unspecified",
1158         [SESSION_TTY] = "tty",
1159         [SESSION_X11] = "x11",
1160         [SESSION_WAYLAND] = "wayland",
1161         [SESSION_MIR] = "mir",
1162         [SESSION_WEB] = "web",
1163 };
1164
1165 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1166
1167 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1168         [SESSION_USER] = "user",
1169         [SESSION_GREETER] = "greeter",
1170         [SESSION_LOCK_SCREEN] = "lock-screen",
1171         [SESSION_BACKGROUND] = "background"
1172 };
1173
1174 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1175
1176 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1177         [KILL_LEADER] = "leader",
1178         [KILL_ALL] = "all"
1179 };
1180
1181 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);