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