src/login/logind-session.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2011 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <linux/kd.h>
  23 #include <linux/vt.h>
  24 #include <signal.h>
  25 #include <string.h>
  26 #include <sys/ioctl.h>
  27 #include <unistd.h>
  28
  29 #include "sd-messages.h"
  30
  31 #include "alloc-util.h"
  32 #include "audit-util.h"
  33 #include "bus-error.h"
  34 #include "bus-util.h"
  35 #include "escape.h"
  36 #include "fd-util.h"
  37 #include "fileio.h"
  38 #include "format-util.h"
  39 #include "io-util.h"
  40 #include "logind-session.h"
  41 #include "mkdir.h"
  42 #include "parse-util.h"
  43 #include "path-util.h"
  44 #include "string-table.h"
  45 #include "terminal-util.h"
  46 #include "user-util.h"
  47 #include "util.h"
  48 #include "process-util.h"
  49
  50 #define RELEASE_USEC (20*USEC_PER_SEC)
  51
  52 static void session_remove_fifo(Session *s);
  53
  54 Session* session_new(Manager *m, const char *id) {
  55         Session *s;
  56
  57         assert(m);
  58         assert(id);
  59         assert(session_id_valid(id));
  60
  61         s = new0(Session, 1);
  62         if (!s)
  63                 return NULL;
  64
  65         s->state_file = strappend("/run/systemd/sessions/", id);
  66         if (!s->state_file)
  67                 return mfree(s);
  68
  69         s->devices = hashmap_new(&devt_hash_ops);
  70         if (!s->devices) {
  71                 free(s->state_file);
  72                 return mfree(s);
  73         }
  74
  75         s->id = basename(s->state_file);
  76
  77         if (hashmap_put(m->sessions, s->id, s) < 0) {
  78                 hashmap_free(s->devices);
  79                 free(s->state_file);
  80                 return mfree(s);
  81         }
  82
  83         s->manager = m;
  84         s->fifo_fd = -1;
  85         s->vtfd = -1;
  86         s->audit_id = AUDIT_SESSION_INVALID;
  87
  88         return s;
  89 }
  90
  91 void session_free(Session *s) {
  92         SessionDevice *sd;
  93
  94         assert(s);
  95
  96         if (s->in_gc_queue)
  97                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
  98
  99         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 100
 101         session_remove_fifo(s);
 102
 103         session_drop_controller(s);
 104
 105         while ((sd = hashmap_first(s->devices)))
 106                 session_device_free(sd);
 107
 108         hashmap_free(s->devices);
 109
 110         if (s->user) {
 111                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 112
 113                 if (s->user->display == s)
 114                         s->user->display = NULL;
 115         }
 116
 117         if (s->seat) {
 118                 if (s->seat->active == s)
 119                         s->seat->active = NULL;
 120                 if (s->seat->pending_switch == s)
 121                         s->seat->pending_switch = NULL;
 122
 123                 seat_evict_position(s->seat, s);
 124                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 125         }
 126
 127         if (s->scope) {
 128                 hashmap_remove(s->manager->session_units, s->scope);
 129                 free(s->scope);
 130         }
 131
 132         free(s->scope_job);
 133
 134         sd_bus_message_unref(s->create_message);
 135
 136         free(s->tty);
 137         free(s->display);
 138         free(s->remote_host);
 139         free(s->remote_user);
 140         free(s->service);
 141         free(s->desktop);
 142
 143         hashmap_remove(s->manager->sessions, s->id);
 144
 145         free(s->state_file);
 146         free(s);
 147 }
 148
 149 void session_set_user(Session *s, User *u) {
 150         assert(s);
 151         assert(!s->user);
 152
 153         s->user = u;
 154         LIST_PREPEND(sessions_by_user, u->sessions, s);
 155 }
 156
 157 static void session_save_devices(Session *s, FILE *f) {
 158         SessionDevice *sd;
 159         Iterator i;
 160
 161         if (!hashmap_isempty(s->devices)) {
 162                 fprintf(f, "DEVICES=");
 163                 HASHMAP_FOREACH(sd, s->devices, i)
 164                         fprintf(f, "%u:%u ", major(sd->dev), minor(sd->dev));
 165                 fprintf(f, "\n");
 166         }
 167 }
 168
 169 int session_save(Session *s) {
 170         _cleanup_free_ char *temp_path = NULL;
 171         _cleanup_fclose_ FILE *f = NULL;
 172         int r = 0;
 173
 174         assert(s);
 175
 176         if (!s->user)
 177                 return -ESTALE;
 178
 179         if (!s->started)
 180                 return 0;
 181
 182         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0, false);
 183         if (r < 0)
 184                 goto fail;
 185
 186         r = fopen_temporary(s->state_file, &f, &temp_path);
 187         if (r < 0)
 188                 goto fail;
 189
 190         assert(s->user);
 191
 192         fchmod(fileno(f), 0644);
 193
 194         fprintf(f,
 195                 "# This is private data. Do not parse.\n"
 196                 "UID="UID_FMT"\n"
 197                 "USER=%s\n"
 198                 "ACTIVE=%i\n"
 199                 "STATE=%s\n"
 200                 "REMOTE=%i\n",
 201                 s->user->uid,
 202                 s->user->name,
 203                 session_is_active(s),
 204                 session_state_to_string(session_get_state(s)),
 205                 s->remote);
 206
 207         if (s->type >= 0)
 208                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 209
 210         if (s->class >= 0)
 211                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 212
 213         if (s->scope)
 214                 fprintf(f, "SCOPE=%s\n", s->scope);
 215         if (s->scope_job)
 216                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 217
 218         if (s->fifo_path)
 219                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 220
 221         if (s->seat)
 222                 fprintf(f, "SEAT=%s\n", s->seat->id);
 223
 224         if (s->tty)
 225                 fprintf(f, "TTY=%s\n", s->tty);
 226
 227         if (s->display)
 228                 fprintf(f, "DISPLAY=%s\n", s->display);
 229
 230         if (s->remote_host) {
 231                 _cleanup_free_ char *escaped;
 232
 233                 escaped = cescape(s->remote_host);
 234                 if (!escaped) {
 235                         r = -ENOMEM;
 236                         goto fail;
 237                 }
 238
 239                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 240         }
 241
 242         if (s->remote_user) {
 243                 _cleanup_free_ char *escaped;
 244
 245                 escaped = cescape(s->remote_user);
 246                 if (!escaped) {
 247                         r = -ENOMEM;
 248                         goto fail;
 249                 }
 250
 251                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 252         }
 253
 254         if (s->service) {
 255                 _cleanup_free_ char *escaped;
 256
 257                 escaped = cescape(s->service);
 258                 if (!escaped) {
 259                         r = -ENOMEM;
 260                         goto fail;
 261                 }
 262
 263                 fprintf(f, "SERVICE=%s\n", escaped);
 264         }
 265
 266         if (s->desktop) {
 267                 _cleanup_free_ char *escaped;
 268
 269
 270                 escaped = cescape(s->desktop);
 271                 if (!escaped) {
 272                         r = -ENOMEM;
 273                         goto fail;
 274                 }
 275
 276                 fprintf(f, "DESKTOP=%s\n", escaped);
 277         }
 278
 279         if (s->seat && seat_has_vts(s->seat))
 280                 fprintf(f, "VTNR=%u\n", s->vtnr);
 281
 282         if (!s->vtnr)
 283                 fprintf(f, "POSITION=%u\n", s->position);
 284
 285         if (pid_is_valid(s->leader))
 286                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 287
 288         if (audit_session_is_valid(s->audit_id))
 289                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 290
 291         if (dual_timestamp_is_set(&s->timestamp))
 292                 fprintf(f,
 293                         "REALTIME="USEC_FMT"\n"
 294                         "MONOTONIC="USEC_FMT"\n",
 295                         s->timestamp.realtime,
 296                         s->timestamp.monotonic);
 297
 298         if (s->controller) {
 299                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 300                 session_save_devices(s, f);
 301         }
 302
 303         r = fflush_and_check(f);
 304         if (r < 0)
 305                 goto fail;
 306
 307         if (rename(temp_path, s->state_file) < 0) {
 308                 r = -errno;
 309                 goto fail;
 310         }
 311
 312         return 0;
 313
 314 fail:
 315         (void) unlink(s->state_file);
 316
 317         if (temp_path)
 318                 (void) unlink(temp_path);
 319
 320         return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 321 }
 322
 323 static int session_load_devices(Session *s, const char *devices) {
 324         const char *p;
 325         int r = 0;
 326
 327         assert(s);
 328
 329         for (p = devices;;) {
 330                 _cleanup_free_ char *word = NULL;
 331                 SessionDevice *sd;
 332                 dev_t dev;
 333                 int k;
 334
 335                 k = extract_first_word(&p, &word, NULL, 0);
 336                 if (k == 0)
 337                         break;
 338                 if (k < 0) {
 339                         r = k;
 340                         break;
 341                 }
 342
 343                 k = parse_dev(word, &dev);
 344                 if (k < 0) {
 345                         r = k;
 346                         continue;
 347                 }
 348
 349                 /* The file descriptors for loaded devices will be reattached later. */
 350                 k = session_device_new(s, dev, false, &sd);
 351                 if (k < 0)
 352                         r = k;
 353         }
 354
 355         if (r < 0)
 356                 log_error_errno(r, "Loading session devices for session %s failed: %m", s->id);
 357
 358         return r;
 359 }
 360
 361 int session_load(Session *s) {
 362         _cleanup_free_ char *remote = NULL,
 363                 *seat = NULL,
 364                 *vtnr = NULL,
 365                 *state = NULL,
 366                 *position = NULL,
 367                 *leader = NULL,
 368                 *type = NULL,
 369                 *class = NULL,
 370                 *uid = NULL,
 371                 *realtime = NULL,
 372                 *monotonic = NULL,
 373                 *controller = NULL,
 374                 *active = NULL,
 375                 *devices = NULL;
 376
 377         int k, r;
 378
 379         assert(s);
 380
 381         r = parse_env_file(s->state_file, NEWLINE,
 382                            "REMOTE",         &remote,
 383                            "SCOPE",          &s->scope,
 384                            "SCOPE_JOB",      &s->scope_job,
 385                            "FIFO",           &s->fifo_path,
 386                            "SEAT",           &seat,
 387                            "TTY",            &s->tty,
 388                            "DISPLAY",        &s->display,
 389                            "REMOTE_HOST",    &s->remote_host,
 390                            "REMOTE_USER",    &s->remote_user,
 391                            "SERVICE",        &s->service,
 392                            "DESKTOP",        &s->desktop,
 393                            "VTNR",           &vtnr,
 394                            "STATE",          &state,
 395                            "POSITION",       &position,
 396                            "LEADER",         &leader,
 397                            "TYPE",           &type,
 398                            "CLASS",          &class,
 399                            "UID",            &uid,
 400                            "REALTIME",       &realtime,
 401                            "MONOTONIC",      &monotonic,
 402                            "CONTROLLER",     &controller,
 403                            "ACTIVE",         &active,
 404                            "DEVICES",        &devices,
 405                            NULL);
 406
 407         if (r < 0)
 408                 return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 409
 410         if (!s->user) {
 411                 uid_t u;
 412                 User *user;
 413
 414                 if (!uid) {
 415                         log_error("UID not specified for session %s", s->id);
 416                         return -ENOENT;
 417                 }
 418
 419                 r = parse_uid(uid, &u);
 420                 if (r < 0)  {
 421                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 422                         return r;
 423                 }
 424
 425                 user = hashmap_get(s->manager->users, UID_TO_PTR(u));
 426                 if (!user) {
 427                         log_error("User of session %s not known.", s->id);
 428                         return -ENOENT;
 429                 }
 430
 431                 session_set_user(s, user);
 432         }
 433
 434         if (remote) {
 435                 k = parse_boolean(remote);
 436                 if (k >= 0)
 437                         s->remote = k;
 438         }
 439
 440         if (vtnr)
 441                 safe_atou(vtnr, &s->vtnr);
 442
 443         if (seat && !s->seat) {
 444                 Seat *o;
 445
 446                 o = hashmap_get(s->manager->seats, seat);
 447                 if (o)
 448                         r = seat_attach_session(o, s);
 449                 if (!o || r < 0)
 450                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 451         }
 452
 453         if (!s->seat || !seat_has_vts(s->seat))
 454                 s->vtnr = 0;
 455
 456         if (position && s->seat) {
 457                 unsigned int npos;
 458
 459                 safe_atou(position, &npos);
 460                 seat_claim_position(s->seat, s, npos);
 461         }
 462
 463         if (leader) {
 464                 if (parse_pid(leader, &s->leader) >= 0)
 465                         (void) audit_session_from_pid(s->leader, &s->audit_id);
 466         }
 467
 468         if (type) {
 469                 SessionType t;
 470
 471                 t = session_type_from_string(type);
 472                 if (t >= 0)
 473                         s->type = t;
 474         }
 475
 476         if (class) {
 477                 SessionClass c;
 478
 479                 c = session_class_from_string(class);
 480                 if (c >= 0)
 481                         s->class = c;
 482         }
 483
 484         if (state && streq(state, "closing"))
 485                 s->stopping = true;
 486
 487         if (s->fifo_path) {
 488                 int fd;
 489
 490                 /* If we open an unopened pipe for reading we will not
 491                    get an EOF. to trigger an EOF we hence open it for
 492                    writing, but close it right away which then will
 493                    trigger the EOF. This will happen immediately if no
 494                    other process has the FIFO open for writing, i. e.
 495                    when the session died before logind (re)started. */
 496
 497                 fd = session_create_fifo(s);
 498                 safe_close(fd);
 499         }
 500
 501         if (realtime)
 502                 timestamp_deserialize(realtime, &s->timestamp.realtime);
 503         if (monotonic)
 504                 timestamp_deserialize(monotonic, &s->timestamp.monotonic);
 505
 506         if (active) {
 507                 k = parse_boolean(active);
 508                 if (k >= 0)
 509                         s->was_active = k;
 510         }
 511
 512         if (controller) {
 513                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0) {
 514                         session_set_controller(s, controller, false, false);
 515                         session_load_devices(s, devices);
 516                 } else
 517                         session_restore_vt(s);
 518         }
 519
 520         return r;
 521 }
 522
 523 int session_activate(Session *s) {
 524         unsigned int num_pending;
 525
 526         assert(s);
 527         assert(s->user);
 528
 529         if (!s->seat)
 530                 return -EOPNOTSUPP;
 531
 532         if (s->seat->active == s)
 533                 return 0;
 534
 535         /* on seats with VTs, we let VTs manage session-switching */
 536         if (seat_has_vts(s->seat)) {
 537                 if (!s->vtnr)
 538                         return -EOPNOTSUPP;
 539
 540                 return chvt(s->vtnr);
 541         }
 542
 543         /* On seats without VTs, we implement session-switching in logind. We
 544          * try to pause all session-devices and wait until the session
 545          * controller acknowledged them. Once all devices are asleep, we simply
 546          * switch the active session and be done.
 547          * We save the session we want to switch to in seat->pending_switch and
 548          * seat_complete_switch() will perform the final switch. */
 549
 550         s->seat->pending_switch = s;
 551
 552         /* if no devices are running, immediately perform the session switch */
 553         num_pending = session_device_try_pause_all(s);
 554         if (!num_pending)
 555                 seat_complete_switch(s->seat);
 556
 557         return 0;
 558 }
 559
 560 static int session_start_scope(Session *s) {
 561         int r;
 562
 563         assert(s);
 564         assert(s->user);
 565
 566         if (!s->scope) {
 567                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 568                 char *scope, *job = NULL;
 569                 const char *description;
 570
 571                 scope = strjoin("session-", s->id, ".scope");
 572                 if (!scope)
 573                         return log_oom();
 574
 575                 description = strjoina("Session ", s->id, " of user ", s->user->name);
 576
 577                 r = manager_start_scope(
 578                                 s->manager,
 579                                 scope,
 580                                 s->leader,
 581                                 s->user->slice,
 582                                 description,
 583                                 "systemd-logind.service",
 584                                 "systemd-user-sessions.service",
 585                                 (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */
 586                                 &error,
 587                                 &job);
 588                 if (r < 0) {
 589                         log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));
 590                         free(scope);
 591                         return r;
 592                 } else {
 593                         s->scope = scope;
 594
 595                         free(s->scope_job);
 596                         s->scope_job = job;
 597                 }
 598         }
 599
 600         if (s->scope)
 601                 (void) hashmap_put(s->manager->session_units, s->scope, s);
 602
 603         return 0;
 604 }
 605
 606 int session_start(Session *s) {
 607         int r;
 608
 609         assert(s);
 610
 611         if (!s->user)
 612                 return -ESTALE;
 613
 614         if (s->started)
 615                 return 0;
 616
 617         r = user_start(s->user);
 618         if (r < 0)
 619                 return r;
 620
 621         /* Create cgroup */
 622         r = session_start_scope(s);
 623         if (r < 0)
 624                 return r;
 625
 626         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 627                    "MESSAGE_ID=" SD_MESSAGE_SESSION_START_STR,
 628                    "SESSION_ID=%s", s->id,
 629                    "USER_ID=%s", s->user->name,
 630                    "LEADER="PID_FMT, s->leader,
 631                    LOG_MESSAGE("New session %s of user %s.", s->id, s->user->name),
 632                    NULL);
 633
 634         if (!dual_timestamp_is_set(&s->timestamp))
 635                 dual_timestamp_get(&s->timestamp);
 636
 637         if (s->seat)
 638                 seat_read_active_vt(s->seat);
 639
 640         s->started = true;
 641
 642         user_elect_display(s->user);
 643
 644         /* Save data */
 645         session_save(s);
 646         user_save(s->user);
 647         if (s->seat)
 648                 seat_save(s->seat);
 649
 650         /* Send signals */
 651         session_send_signal(s, true);
 652         user_send_changed(s->user, "Display", NULL);
 653         if (s->seat) {
 654                 if (s->seat->active == s)
 655                         seat_send_changed(s->seat, "ActiveSession", NULL);
 656         }
 657
 658         return 0;
 659 }
 660
 661 static int session_stop_scope(Session *s, bool force) {
 662         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 663         int r;
 664
 665         assert(s);
 666
 667         if (!s->scope)
 668                 return 0;
 669
 670         /* Let's always abandon the scope first. This tells systemd that we are not interested anymore, and everything
 671          * that is left in the scope is "left-over". Informing systemd about this has the benefit that it will log
 672          * when killing any processes left after this point. */
 673         r = manager_abandon_scope(s->manager, s->scope, &error);
 674         if (r < 0)
 675                 log_warning_errno(r, "Failed to abandon session scope, ignoring: %s", bus_error_message(&error, r));
 676
 677         /* Optionally, let's kill everything that's left now. */
 678         if (force || manager_shall_kill(s->manager, s->user->name)) {
 679                 char *job = NULL;
 680
 681                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 682                 if (r < 0)
 683                         return log_error_errno(r, "Failed to stop session scope: %s", bus_error_message(&error, r));
 684
 685                 free(s->scope_job);
 686                 s->scope_job = job;
 687         } else
 688                 s->scope_job = mfree(s->scope_job);
 689
 690         return 0;
 691 }
 692
 693 int session_stop(Session *s, bool force) {
 694         int r;
 695
 696         assert(s);
 697
 698         if (!s->user)
 699                 return -ESTALE;
 700
 701         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 702
 703         if (s->seat)
 704                 seat_evict_position(s->seat, s);
 705
 706         /* We are going down, don't care about FIFOs anymore */
 707         session_remove_fifo(s);
 708
 709         /* Kill cgroup */
 710         r = session_stop_scope(s, force);
 711
 712         s->stopping = true;
 713
 714         user_elect_display(s->user);
 715
 716         session_save(s);
 717         user_save(s->user);
 718
 719         return r;
 720 }
 721
 722 int session_finalize(Session *s) {
 723         SessionDevice *sd;
 724
 725         assert(s);
 726
 727         if (!s->user)
 728                 return -ESTALE;
 729
 730         if (s->started)
 731                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 732                            "MESSAGE_ID=" SD_MESSAGE_SESSION_STOP_STR,
 733                            "SESSION_ID=%s", s->id,
 734                            "USER_ID=%s", s->user->name,
 735                            "LEADER="PID_FMT, s->leader,
 736                            LOG_MESSAGE("Removed session %s.", s->id),
 737                            NULL);
 738
 739         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 740
 741         if (s->seat)
 742                 seat_evict_position(s->seat, s);
 743
 744         /* Kill session devices */
 745         while ((sd = hashmap_first(s->devices)))
 746                 session_device_free(sd);
 747
 748         (void) unlink(s->state_file);
 749         session_add_to_gc_queue(s);
 750         user_add_to_gc_queue(s->user);
 751
 752         if (s->started) {
 753                 session_send_signal(s, false);
 754                 s->started = false;
 755         }
 756
 757         if (s->seat) {
 758                 if (s->seat->active == s)
 759                         seat_set_active(s->seat, NULL);
 760
 761                 seat_save(s->seat);
 762         }
 763
 764         user_save(s->user);
 765         user_send_changed(s->user, "Display", NULL);
 766
 767         return 0;
 768 }
 769
 770 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 771         Session *s = userdata;
 772
 773         assert(es);
 774         assert(s);
 775
 776         session_stop(s, false);
 777         return 0;
 778 }
 779
 780 int session_release(Session *s) {
 781         assert(s);
 782
 783         if (!s->started || s->stopping)
 784                 return 0;
 785
 786         if (s->timer_event_source)
 787                 return 0;
 788
 789         return sd_event_add_time(s->manager->event,
 790                                  &s->timer_event_source,
 791                                  CLOCK_MONOTONIC,
 792                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 793                                  release_timeout_callback, s);
 794 }
 795
 796 bool session_is_active(Session *s) {
 797         assert(s);
 798
 799         if (!s->seat)
 800                 return true;
 801
 802         return s->seat->active == s;
 803 }
 804
 805 static int get_tty_atime(const char *tty, usec_t *atime) {
 806         _cleanup_free_ char *p = NULL;
 807         struct stat st;
 808
 809         assert(tty);
 810         assert(atime);
 811
 812         if (!path_is_absolute(tty)) {
 813                 p = strappend("/dev/", tty);
 814                 if (!p)
 815                         return -ENOMEM;
 816
 817                 tty = p;
 818         } else if (!path_startswith(tty, "/dev/"))
 819                 return -ENOENT;
 820
 821         if (lstat(tty, &st) < 0)
 822                 return -errno;
 823
 824         *atime = timespec_load(&st.st_atim);
 825         return 0;
 826 }
 827
 828 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 829         _cleanup_free_ char *p = NULL;
 830         int r;
 831
 832         assert(pid > 0);
 833         assert(atime);
 834
 835         r = get_ctty(pid, NULL, &p);
 836         if (r < 0)
 837                 return r;
 838
 839         return get_tty_atime(p, atime);
 840 }
 841
 842 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 843         usec_t atime = 0, n;
 844         int r;
 845
 846         assert(s);
 847
 848         /* Explicit idle hint is set */
 849         if (s->idle_hint) {
 850                 if (t)
 851                         *t = s->idle_hint_timestamp;
 852
 853                 return s->idle_hint;
 854         }
 855
 856         /* Graphical sessions should really implement a real
 857          * idle hint logic */
 858         if (SESSION_TYPE_IS_GRAPHICAL(s->type))
 859                 goto dont_know;
 860
 861         /* For sessions with an explicitly configured tty, let's check
 862          * its atime */
 863         if (s->tty) {
 864                 r = get_tty_atime(s->tty, &atime);
 865                 if (r >= 0)
 866                         goto found_atime;
 867         }
 868
 869         /* For sessions with a leader but no explicitly configured
 870          * tty, let's check the controlling tty of the leader */
 871         if (s->leader > 0) {
 872                 r = get_process_ctty_atime(s->leader, &atime);
 873                 if (r >= 0)
 874                         goto found_atime;
 875         }
 876
 877 dont_know:
 878         if (t)
 879                 *t = s->idle_hint_timestamp;
 880
 881         return 0;
 882
 883 found_atime:
 884         if (t)
 885                 dual_timestamp_from_realtime(t, atime);
 886
 887         n = now(CLOCK_REALTIME);
 888
 889         if (s->manager->idle_action_usec <= 0)
 890                 return 0;
 891
 892         return atime + s->manager->idle_action_usec <= n;
 893 }
 894
 895 void session_set_idle_hint(Session *s, bool b) {
 896         assert(s);
 897
 898         if (s->idle_hint == b)
 899                 return;
 900
 901         s->idle_hint = b;
 902         dual_timestamp_get(&s->idle_hint_timestamp);
 903
 904         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 905
 906         if (s->seat)
 907                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 908
 909         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 910         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 911 }
 912
 913 int session_get_locked_hint(Session *s) {
 914         assert(s);
 915
 916         return s->locked_hint;
 917 }
 918
 919 void session_set_locked_hint(Session *s, bool b) {
 920         assert(s);
 921
 922         if (s->locked_hint == b)
 923                 return;
 924
 925         s->locked_hint = b;
 926
 927         session_send_changed(s, "LockedHint", NULL);
 928 }
 929
 930 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 931         Session *s = userdata;
 932
 933         assert(s);
 934         assert(s->fifo_fd == fd);
 935
 936         /* EOF on the FIFO means the session died abnormally. */
 937
 938         session_remove_fifo(s);
 939         session_stop(s, false);
 940
 941         return 1;
 942 }
 943
 944 int session_create_fifo(Session *s) {
 945         int r;
 946
 947         assert(s);
 948
 949         /* Create FIFO */
 950         if (!s->fifo_path) {
 951                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0, false);
 952                 if (r < 0)
 953                         return r;
 954
 955                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
 956                         return -ENOMEM;
 957
 958                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
 959                         return -errno;
 960         }
 961
 962         /* Open reading side */
 963         if (s->fifo_fd < 0) {
 964                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
 965                 if (s->fifo_fd < 0)
 966                         return -errno;
 967
 968         }
 969
 970         if (!s->fifo_event_source) {
 971                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
 972                 if (r < 0)
 973                         return r;
 974
 975                 /* Let's make sure we noticed dead sessions before we process new bus requests (which might create new
 976                  * sessions). */
 977                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_NORMAL-10);
 978                 if (r < 0)
 979                         return r;
 980         }
 981
 982         /* Open writing side */
 983         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
 984         if (r < 0)
 985                 return -errno;
 986
 987         return r;
 988 }
 989
 990 static void session_remove_fifo(Session *s) {
 991         assert(s);
 992
 993         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
 994         s->fifo_fd = safe_close(s->fifo_fd);
 995
 996         if (s->fifo_path) {
 997                 unlink(s->fifo_path);
 998                 s->fifo_path = mfree(s->fifo_path);
 999         }
1000 }
1001
1002 bool session_check_gc(Session *s, bool drop_not_started) {
1003         assert(s);
1004
1005         if (drop_not_started && !s->started)
1006                 return false;
1007
1008         if (!s->user)
1009                 return false;
1010
1011         if (s->fifo_fd >= 0) {
1012                 if (pipe_eof(s->fifo_fd) <= 0)
1013                         return true;
1014         }
1015
1016         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
1017                 return true;
1018
1019         if (s->scope && manager_unit_is_active(s->manager, s->scope))
1020                 return true;
1021
1022         return false;
1023 }
1024
1025 void session_add_to_gc_queue(Session *s) {
1026         assert(s);
1027
1028         if (s->in_gc_queue)
1029                 return;
1030
1031         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
1032         s->in_gc_queue = true;
1033 }
1034
1035 SessionState session_get_state(Session *s) {
1036         assert(s);
1037
1038         /* always check closing first */
1039         if (s->stopping || s->timer_event_source)
1040                 return SESSION_CLOSING;
1041
1042         if (s->scope_job || s->fifo_fd < 0)
1043                 return SESSION_OPENING;
1044
1045         if (session_is_active(s))
1046                 return SESSION_ACTIVE;
1047
1048         return SESSION_ONLINE;
1049 }
1050
1051 int session_kill(Session *s, KillWho who, int signo) {
1052         assert(s);
1053
1054         if (!s->scope)
1055                 return -ESRCH;
1056
1057         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
1058 }
1059
1060 static int session_open_vt(Session *s) {
1061         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
1062
1063         if (s->vtnr < 1)
1064                 return -ENODEV;
1065
1066         if (s->vtfd >= 0)
1067                 return s->vtfd;
1068
1069         sprintf(path, "/dev/tty%u", s->vtnr);
1070         s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
1071         if (s->vtfd < 0)
1072                 return log_error_errno(s->vtfd, "cannot open VT %s of session %s: %m", path, s->id);
1073
1074         return s->vtfd;
1075 }
1076
1077 int session_prepare_vt(Session *s) {
1078         int vt, r;
1079         struct vt_mode mode = { 0 };
1080
1081         if (s->vtnr < 1)
1082                 return 0;
1083
1084         vt = session_open_vt(s);
1085         if (vt < 0)
1086                 return vt;
1087
1088         r = fchown(vt, s->user->uid, -1);
1089         if (r < 0) {
1090                 r = log_error_errno(errno,
1091                                     "Cannot change owner of /dev/tty%u: %m",
1092                                     s->vtnr);
1093                 goto error;
1094         }
1095
1096         r = ioctl(vt, KDSKBMODE, K_OFF);
1097         if (r < 0) {
1098                 r = log_error_errno(errno,
1099                                     "Cannot set K_OFF on /dev/tty%u: %m",
1100                                     s->vtnr);
1101                 goto error;
1102         }
1103
1104         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1105         if (r < 0) {
1106                 r = log_error_errno(errno,
1107                                     "Cannot set KD_GRAPHICS on /dev/tty%u: %m",
1108                                     s->vtnr);
1109                 goto error;
1110         }
1111
1112         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1113          * So we need a dummy handler here which just acknowledges *all* VT
1114          * switch requests. */
1115         mode.mode = VT_PROCESS;
1116         mode.relsig = SIGRTMIN;
1117         mode.acqsig = SIGRTMIN + 1;
1118         r = ioctl(vt, VT_SETMODE, &mode);
1119         if (r < 0) {
1120                 r = log_error_errno(errno,
1121                                     "Cannot set VT_PROCESS on /dev/tty%u: %m",
1122                                     s->vtnr);
1123                 goto error;
1124         }
1125
1126         return 0;
1127
1128 error:
1129         session_restore_vt(s);
1130         return r;
1131 }
1132
1133 void session_restore_vt(Session *s) {
1134
1135         static const struct vt_mode mode = {
1136                 .mode = VT_AUTO,
1137         };
1138
1139         int vt, old_fd;
1140
1141         /* We need to get a fresh handle to the virtual terminal,
1142          * since the old file-descriptor is potentially in a hung-up
1143          * state after the controlling process exited; we do a
1144          * little dance to avoid having the terminal be available
1145          * for reuse before we've cleaned it up.
1146          */
1147         old_fd = s->vtfd;
1148         s->vtfd = -1;
1149
1150         vt = session_open_vt(s);
1151         safe_close(old_fd);
1152
1153         if (vt < 0)
1154                 return;
1155
1156         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1157
1158         (void) vt_reset_keyboard(vt);
1159
1160         (void) ioctl(vt, VT_SETMODE, &mode);
1161         (void) fchown(vt, 0, (gid_t) -1);
1162
1163         s->vtfd = safe_close(s->vtfd);
1164 }
1165
1166 void session_leave_vt(Session *s) {
1167         int r;
1168
1169         assert(s);
1170
1171         /* This is called whenever we get a VT-switch signal from the kernel.
1172          * We acknowledge all of them unconditionally. Note that session are
1173          * free to overwrite those handlers and we only register them for
1174          * sessions with controllers. Legacy sessions are not affected.
1175          * However, if we switch from a non-legacy to a legacy session, we must
1176          * make sure to pause all device before acknowledging the switch. We
1177          * process the real switch only after we are notified via sysfs, so the
1178          * legacy session might have already started using the devices. If we
1179          * don't pause the devices before the switch, we might confuse the
1180          * session we switch to. */
1181
1182         if (s->vtfd < 0)
1183                 return;
1184
1185         session_device_pause_all(s);
1186         r = ioctl(s->vtfd, VT_RELDISP, 1);
1187         if (r < 0)
1188                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1189 }
1190
1191 bool session_is_controller(Session *s, const char *sender) {
1192         assert(s);
1193
1194         return streq_ptr(s->controller, sender);
1195 }
1196
1197 static void session_release_controller(Session *s, bool notify) {
1198         _cleanup_free_ char *name = NULL;
1199         SessionDevice *sd;
1200
1201         if (!s->controller)
1202                 return;
1203
1204         name = s->controller;
1205
1206         /* By resetting the controller before releasing the devices, we won't
1207          * send notification signals. This avoids sending useless notifications
1208          * if the controller is released on disconnects. */
1209         if (!notify)
1210                 s->controller = NULL;
1211
1212         while ((sd = hashmap_first(s->devices)))
1213                 session_device_free(sd);
1214
1215         s->controller = NULL;
1216         s->track = sd_bus_track_unref(s->track);
1217 }
1218
1219 static int on_bus_track(sd_bus_track *track, void *userdata) {
1220         Session *s = userdata;
1221
1222         assert(track);
1223         assert(s);
1224
1225         session_drop_controller(s);
1226
1227         return 0;
1228 }
1229
1230 int session_set_controller(Session *s, const char *sender, bool force, bool prepare) {
1231         _cleanup_free_ char *name = NULL;
1232         int r;
1233
1234         assert(s);
1235         assert(sender);
1236
1237         if (session_is_controller(s, sender))
1238                 return 0;
1239         if (s->controller && !force)
1240                 return -EBUSY;
1241
1242         name = strdup(sender);
1243         if (!name)
1244                 return -ENOMEM;
1245
1246         s->track = sd_bus_track_unref(s->track);
1247         r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
1248         if (r < 0)
1249                 return r;
1250
1251         r = sd_bus_track_add_name(s->track, name);
1252         if (r < 0)
1253                 return r;
1254
1255         /* When setting a session controller, we forcibly mute the VT and set
1256          * it into graphics-mode. Applications can override that by changing
1257          * VT state after calling TakeControl(). However, this serves as a good
1258          * default and well-behaving controllers can now ignore VTs entirely.
1259          * Note that we reset the VT on ReleaseControl() and if the controller
1260          * exits.
1261          * If logind crashes/restarts, we restore the controller during restart
1262          * (without preparing the VT since the controller has probably overridden
1263          * VT state by now) or reset the VT in case it crashed/exited, too. */
1264         if (prepare) {
1265                 r = session_prepare_vt(s);
1266                 if (r < 0) {
1267                         s->track = sd_bus_track_unref(s->track);
1268                         return r;
1269                 }
1270         }
1271
1272         session_release_controller(s, true);
1273         s->controller = name;
1274         name = NULL;
1275         session_save(s);
1276
1277         return 0;
1278 }
1279
1280 void session_drop_controller(Session *s) {
1281         assert(s);
1282
1283         if (!s->controller)
1284                 return;
1285
1286         s->track = sd_bus_track_unref(s->track);
1287         session_release_controller(s, false);
1288         session_save(s);
1289         session_restore_vt(s);
1290 }
1291
1292 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1293         [SESSION_OPENING] = "opening",
1294         [SESSION_ONLINE] = "online",
1295         [SESSION_ACTIVE] = "active",
1296         [SESSION_CLOSING] = "closing"
1297 };
1298
1299 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1300
1301 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1302         [SESSION_UNSPECIFIED] = "unspecified",
1303         [SESSION_TTY] = "tty",
1304         [SESSION_X11] = "x11",
1305         [SESSION_WAYLAND] = "wayland",
1306         [SESSION_MIR] = "mir",
1307         [SESSION_WEB] = "web",
1308 };
1309
1310 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1311
1312 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1313         [SESSION_USER] = "user",
1314         [SESSION_GREETER] = "greeter",
1315         [SESSION_LOCK_SCREEN] = "lock-screen",
1316         [SESSION_BACKGROUND] = "background"
1317 };
1318
1319 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1320
1321 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1322         [KILL_LEADER] = "leader",
1323         [KILL_ALL] = "all"
1324 };
1325
1326 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);