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