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 "extract-word.h"
  37 #include "fd-util.h"
  38 #include "fileio.h"
  39 #include "format-util.h"
  40 #include "io-util.h"
  41 #include "logind-session.h"
  42 #include "mkdir.h"
  43 #include "parse-util.h"
  44 #include "path-util.h"
  45 #include "string-table.h"
  46 #include "terminal-util.h"
  47 #include "user-util.h"
  48 #include "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
  87         return s;
  88 }
  89
  90 void session_free(Session *s) {
  91         SessionDevice *sd;
  92
  93         assert(s);
  94
  95         if (s->in_gc_queue)
  96                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
  97
  98         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  99
 100         session_remove_fifo(s);
 101
 102         session_drop_controller(s);
 103
 104         while ((sd = hashmap_first(s->devices)))
 105                 session_device_free(sd);
 106
 107         hashmap_free(s->devices);
 108
 109         if (s->user) {
 110                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 111
 112                 if (s->user->display == s)
 113                         s->user->display = NULL;
 114         }
 115
 116         if (s->seat) {
 117                 if (s->seat->active == s)
 118                         s->seat->active = NULL;
 119                 if (s->seat->pending_switch == s)
 120                         s->seat->pending_switch = NULL;
 121
 122                 seat_evict_position(s->seat, s);
 123                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 124         }
 125
 126         if (s->scope) {
 127                 hashmap_remove(s->manager->session_units, s->scope);
 128                 free(s->scope);
 129         }
 130
 131 #if 0 /// elogind does not support systemd scope_jobs
 132         free(s->scope_job);
 133 #endif // 0
 134
 135         sd_bus_message_unref(s->create_message);
 136
 137         free(s->tty);
 138         free(s->display);
 139         free(s->remote_host);
 140         free(s->remote_user);
 141         free(s->service);
 142         free(s->desktop);
 143
 144         hashmap_remove(s->manager->sessions, s->id);
 145
 146         free(s->state_file);
 147         free(s);
 148 }
 149
 150 void session_set_user(Session *s, User *u) {
 151         assert(s);
 152         assert(!s->user);
 153
 154         s->user = u;
 155         LIST_PREPEND(sessions_by_user, u->sessions, s);
 156 }
 157
 158 static void session_save_devices(Session *s, FILE *f) {
 159         SessionDevice *sd;
 160         Iterator i;
 161
 162         if (!hashmap_isempty(s->devices)) {
 163                 fprintf(f, "DEVICES=");
 164                 HASHMAP_FOREACH(sd, s->devices, i)
 165                         fprintf(f, "%u:%u ", major(sd->dev), minor(sd->dev));
 166                 fprintf(f, "\n");
 167         }
 168 }
 169
 170 int session_save(Session *s) {
 171         _cleanup_free_ char *temp_path = NULL;
 172         _cleanup_fclose_ FILE *f = NULL;
 173         int r = 0;
 174
 175         assert(s);
 176
 177         if (!s->user)
 178                 return -ESTALE;
 179
 180         if (!s->started)
 181                 return 0;
 182
 183         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 184         if (r < 0)
 185                 goto fail;
 186
 187         r = fopen_temporary(s->state_file, &f, &temp_path);
 188         if (r < 0)
 189                 goto fail;
 190
 191         assert(s->user);
 192
 193         fchmod(fileno(f), 0644);
 194
 195         fprintf(f,
 196                 "# This is private data. Do not parse.\n"
 197                 "UID="UID_FMT"\n"
 198                 "USER=%s\n"
 199                 "ACTIVE=%i\n"
 200                 "STATE=%s\n"
 201                 "REMOTE=%i\n",
 202                 s->user->uid,
 203                 s->user->name,
 204                 session_is_active(s),
 205                 session_state_to_string(session_get_state(s)),
 206                 s->remote);
 207
 208         if (s->type >= 0)
 209                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 210
 211         if (s->class >= 0)
 212                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 213
 214         if (s->scope)
 215                 fprintf(f, "SCOPE=%s\n", s->scope);
 216 #if 0 /// elogind does not support systemd scope_jobs
 217         if (s->scope_job)
 218                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 219 #endif // 0
 220
 221         if (s->fifo_path)
 222                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 223
 224         if (s->seat)
 225                 fprintf(f, "SEAT=%s\n", s->seat->id);
 226
 227         if (s->tty)
 228                 fprintf(f, "TTY=%s\n", s->tty);
 229
 230         if (s->display)
 231                 fprintf(f, "DISPLAY=%s\n", s->display);
 232
 233         if (s->remote_host) {
 234                 _cleanup_free_ char *escaped;
 235
 236                 escaped = cescape(s->remote_host);
 237                 if (!escaped) {
 238                         r = -ENOMEM;
 239                         goto fail;
 240                 }
 241
 242                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 243         }
 244
 245         if (s->remote_user) {
 246                 _cleanup_free_ char *escaped;
 247
 248                 escaped = cescape(s->remote_user);
 249                 if (!escaped) {
 250                         r = -ENOMEM;
 251                         goto fail;
 252                 }
 253
 254                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 255         }
 256
 257         if (s->service) {
 258                 _cleanup_free_ char *escaped;
 259
 260                 escaped = cescape(s->service);
 261                 if (!escaped) {
 262                         r = -ENOMEM;
 263                         goto fail;
 264                 }
 265
 266                 fprintf(f, "SERVICE=%s\n", escaped);
 267         }
 268
 269         if (s->desktop) {
 270                 _cleanup_free_ char *escaped;
 271
 272
 273                 escaped = cescape(s->desktop);
 274                 if (!escaped) {
 275                         r = -ENOMEM;
 276                         goto fail;
 277                 }
 278
 279                 fprintf(f, "DESKTOP=%s\n", escaped);
 280         }
 281
 282         if (s->seat && seat_has_vts(s->seat))
 283                 fprintf(f, "VTNR=%u\n", s->vtnr);
 284
 285         if (!s->vtnr)
 286                 fprintf(f, "POSITION=%u\n", s->position);
 287
 288         if (s->leader > 0)
 289                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 290
 291         if (s->audit_id > 0)
 292                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 293
 294         if (dual_timestamp_is_set(&s->timestamp))
 295                 fprintf(f,
 296                         "REALTIME="USEC_FMT"\n"
 297                         "MONOTONIC="USEC_FMT"\n",
 298                         s->timestamp.realtime,
 299                         s->timestamp.monotonic);
 300
 301         if (s->controller) {
 302                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 303                 session_save_devices(s, f);
 304         }
 305
 306         r = fflush_and_check(f);
 307         if (r < 0)
 308                 goto fail;
 309
 310         if (rename(temp_path, s->state_file) < 0) {
 311                 r = -errno;
 312                 goto fail;
 313         }
 314
 315         return 0;
 316
 317 fail:
 318         (void) unlink(s->state_file);
 319
 320         if (temp_path)
 321                 (void) unlink(temp_path);
 322
 323         return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 324 }
 325
 326 static int session_load_devices(Session *s, const char *devices) {
 327         const char *p;
 328         int r = 0;
 329
 330         assert(s);
 331
 332         for (p = devices;;) {
 333                 _cleanup_free_ char *word = NULL;
 334                 SessionDevice *sd;
 335                 dev_t dev;
 336                 int k;
 337
 338                 k = extract_first_word(&p, &word, NULL, 0);
 339                 if (k == 0)
 340                         break;
 341                 if (k < 0) {
 342                         r = k;
 343                         break;
 344                 }
 345
 346                 k = parse_dev(word, &dev);
 347                 if (k < 0) {
 348                         r = k;
 349                         continue;
 350                 }
 351
 352                 /* The file descriptors for loaded devices will be reattached later. */
 353                 k = session_device_new(s, dev, false, &sd);
 354                 if (k < 0)
 355                         r = k;
 356         }
 357
 358         if (r < 0)
 359                 log_error_errno(r, "Loading session devices for session %s failed: %m", s->id);
 360
 361         return r;
 362 }
 363
 364 int session_load(Session *s) {
 365         _cleanup_free_ char *remote = NULL,
 366                 *seat = NULL,
 367                 *vtnr = NULL,
 368                 *state = NULL,
 369                 *position = NULL,
 370                 *leader = NULL,
 371                 *type = NULL,
 372                 *class = NULL,
 373                 *uid = NULL,
 374                 *realtime = NULL,
 375                 *monotonic = NULL,
 376                 *controller = NULL,
 377                 *active = NULL,
 378                 *devices = NULL;
 379
 380         int k, r;
 381
 382         assert(s);
 383
 384         r = parse_env_file(s->state_file, NEWLINE,
 385                            "REMOTE",         &remote,
 386                            "SCOPE",          &s->scope,
 387 #if 0 /// elogind does not support systemd scope_jobs
 388                            "SCOPE_JOB",      &s->scope_job,
 389 #endif // 0
 390                            "FIFO",           &s->fifo_path,
 391                            "SEAT",           &seat,
 392                            "TTY",            &s->tty,
 393                            "DISPLAY",        &s->display,
 394                            "REMOTE_HOST",    &s->remote_host,
 395                            "REMOTE_USER",    &s->remote_user,
 396                            "SERVICE",        &s->service,
 397                            "DESKTOP",        &s->desktop,
 398                            "VTNR",           &vtnr,
 399                            "STATE",          &state,
 400                            "POSITION",       &position,
 401                            "LEADER",         &leader,
 402                            "TYPE",           &type,
 403                            "CLASS",          &class,
 404                            "UID",            &uid,
 405                            "REALTIME",       &realtime,
 406                            "MONOTONIC",      &monotonic,
 407                            "CONTROLLER",     &controller,
 408                            "ACTIVE",         &active,
 409                            "DEVICES",        &devices,
 410                            NULL);
 411
 412         if (r < 0)
 413                 return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 414
 415         if (!s->user) {
 416                 uid_t u;
 417                 User *user;
 418
 419                 if (!uid) {
 420                         log_error("UID not specified for session %s", s->id);
 421                         return -ENOENT;
 422                 }
 423
 424                 r = parse_uid(uid, &u);
 425                 if (r < 0)  {
 426                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 427                         return r;
 428                 }
 429
 430                 user = hashmap_get(s->manager->users, UID_TO_PTR(u));
 431                 if (!user) {
 432                         log_error("User of session %s not known.", s->id);
 433                         return -ENOENT;
 434                 }
 435
 436                 session_set_user(s, user);
 437         }
 438
 439         if (remote) {
 440                 k = parse_boolean(remote);
 441                 if (k >= 0)
 442                         s->remote = k;
 443         }
 444
 445         if (vtnr)
 446                 safe_atou(vtnr, &s->vtnr);
 447
 448         if (seat && !s->seat) {
 449                 Seat *o;
 450
 451                 o = hashmap_get(s->manager->seats, seat);
 452                 if (o)
 453                         r = seat_attach_session(o, s);
 454                 if (!o || r < 0)
 455                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 456         }
 457
 458         if (!s->seat || !seat_has_vts(s->seat))
 459                 s->vtnr = 0;
 460
 461         if (position && s->seat) {
 462                 unsigned int npos;
 463
 464                 safe_atou(position, &npos);
 465                 seat_claim_position(s->seat, s, npos);
 466         }
 467
 468         if (leader) {
 469                 k = parse_pid(leader, &s->leader);
 470                 if (k >= 0)
 471                         audit_session_from_pid(s->leader, &s->audit_id);
 472         }
 473
 474         if (type) {
 475                 SessionType t;
 476
 477                 t = session_type_from_string(type);
 478                 if (t >= 0)
 479                         s->type = t;
 480         }
 481
 482         if (class) {
 483                 SessionClass c;
 484
 485                 c = session_class_from_string(class);
 486                 if (c >= 0)
 487                         s->class = c;
 488         }
 489
 490         if (state && streq(state, "closing"))
 491                 s->stopping = true;
 492
 493         if (s->fifo_path) {
 494                 int fd;
 495
 496                 /* If we open an unopened pipe for reading we will not
 497                    get an EOF. to trigger an EOF we hence open it for
 498                    writing, but close it right away which then will
 499                    trigger the EOF. This will happen immediately if no
 500                    other process has the FIFO open for writing, i. e.
 501                    when the session died before logind (re)started. */
 502
 503                 fd = session_create_fifo(s);
 504                 safe_close(fd);
 505         }
 506
 507         if (realtime)
 508                 timestamp_deserialize(realtime, &s->timestamp.realtime);
 509         if (monotonic)
 510                 timestamp_deserialize(monotonic, &s->timestamp.monotonic);
 511
 512         if (active) {
 513                 k = parse_boolean(active);
 514                 if (k >= 0)
 515                         s->was_active = k;
 516         }
 517
 518         if (controller) {
 519                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0) {
 520                         session_set_controller(s, controller, false, false);
 521                         session_load_devices(s, devices);
 522                 } else
 523                         session_restore_vt(s);
 524         }
 525
 526         return r;
 527 }
 528
 529 int session_activate(Session *s) {
 530         unsigned int num_pending;
 531
 532         assert(s);
 533         assert(s->user);
 534
 535         if (!s->seat)
 536                 return -EOPNOTSUPP;
 537
 538         if (s->seat->active == s)
 539                 return 0;
 540
 541         /* on seats with VTs, we let VTs manage session-switching */
 542         if (seat_has_vts(s->seat)) {
 543                 if (!s->vtnr)
 544                         return -EOPNOTSUPP;
 545
 546                 return chvt(s->vtnr);
 547         }
 548
 549         /* On seats without VTs, we implement session-switching in logind. We
 550          * try to pause all session-devices and wait until the session
 551          * controller acknowledged them. Once all devices are asleep, we simply
 552          * switch the active session and be done.
 553          * We save the session we want to switch to in seat->pending_switch and
 554          * seat_complete_switch() will perform the final switch. */
 555
 556         s->seat->pending_switch = s;
 557
 558         /* if no devices are running, immediately perform the session switch */
 559         num_pending = session_device_try_pause_all(s);
 560         if (!num_pending)
 561                 seat_complete_switch(s->seat);
 562
 563         return 0;
 564 }
 565
 566 #if 0 /// UNNEEDED by elogind
 567 static int session_start_scope(Session *s) {
 568         int r;
 569
 570         assert(s);
 571         assert(s->user);
 572
 573         if (!s->scope) {
 574                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 575                 char *scope, *job = NULL;
 576                 const char *description;
 577
 578                 scope = strjoin("session-", s->id, ".scope");
 579                 if (!scope)
 580                         return log_oom();
 581
 582                 description = strjoina("Session ", s->id, " of user ", s->user->name);
 583
 584                 r = manager_start_scope(
 585                                 s->manager,
 586                                 scope,
 587                                 s->leader,
 588                                 s->user->slice,
 589                                 description,
 590                                 "systemd-logind.service",
 591                                 "systemd-user-sessions.service",
 592                                 (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */
 593                                 &error,
 594                                 &job);
 595                 if (r < 0) {
 596                         log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));
 597                         free(scope);
 598                         return r;
 599                 } else {
 600                         s->scope = scope;
 601
 602                         free(s->scope_job);
 603                         s->scope_job = job;
 604                 }
 605         }
 606
 607         if (s->scope)
 608                 (void) hashmap_put(s->manager->session_units, s->scope, s);
 609
 610         return 0;
 611 }
 612 #else
 613 static int session_start_cgroup(Session *s) {
 614         int r;
 615
 616         assert(s);
 617         assert(s->user);
 618         assert(s->leader > 0);
 619
 620         /* First, create our own group */
 621         r = cg_create(SYSTEMD_CGROUP_CONTROLLER, s->id);
 622         if (r < 0)
 623                 return log_error_errno(r, "Failed to create cgroup %s: %m", s->id);
 624
 625         r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, s->id, s->leader);
 626         if (r < 0)
 627                 log_warning_errno(r, "Failed to attach PID %d to cgroup %s: %m", s->leader, s->id);
 628
 629         return 0;
 630 }
 631 #endif // 0
 632
 633 int session_start(Session *s) {
 634         int r;
 635
 636         assert(s);
 637
 638         if (!s->user)
 639                 return -ESTALE;
 640
 641         if (s->started)
 642                 return 0;
 643
 644         r = user_start(s->user);
 645         if (r < 0)
 646                 return r;
 647
 648         /* Create cgroup */
 649 #if 0 /// elogind does its own session management
 650         r = session_start_scope(s);
 651 #else
 652         r = session_start_cgroup(s);
 653 #endif // 0
 654         if (r < 0)
 655                 return r;
 656
 657         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 658                    "MESSAGE_ID=" SD_MESSAGE_SESSION_START_STR,
 659                    "SESSION_ID=%s", s->id,
 660                    "USER_ID=%s", s->user->name,
 661                    "LEADER="PID_FMT, s->leader,
 662                    LOG_MESSAGE("New session %s of user %s.", s->id, s->user->name),
 663                    NULL);
 664
 665         if (!dual_timestamp_is_set(&s->timestamp))
 666                 dual_timestamp_get(&s->timestamp);
 667
 668         if (s->seat)
 669                 seat_read_active_vt(s->seat);
 670
 671         s->started = true;
 672
 673         user_elect_display(s->user);
 674
 675         /* Save data */
 676         session_save(s);
 677         user_save(s->user);
 678         if (s->seat)
 679                 seat_save(s->seat);
 680
 681         /* Send signals */
 682         session_send_signal(s, true);
 683         user_send_changed(s->user, "Display", NULL);
 684         if (s->seat) {
 685                 if (s->seat->active == s)
 686                         seat_send_changed(s->seat, "ActiveSession", NULL);
 687         }
 688
 689         return 0;
 690 }
 691
 692 #if 0 /// UNNEEDED by elogind
 693 static int session_stop_scope(Session *s, bool force) {
 694         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 695         int r;
 696
 697         assert(s);
 698
 699         if (!s->scope)
 700                 return 0;
 701
 702         /* Let's always abandon the scope first. This tells systemd that we are not interested anymore, and everything
 703          * that is left in the scope is "left-over". Informing systemd about this has the benefit that it will log
 704          * when killing any processes left after this point. */
 705         r = manager_abandon_scope(s->manager, s->scope, &error);
 706         if (r < 0)
 707                 log_warning_errno(r, "Failed to abandon session scope, ignoring: %s", bus_error_message(&error, r));
 708
 709         /* Optionally, let's kill everything that's left now. */
 710         if (force || manager_shall_kill(s->manager, s->user->name)) {
 711                 char *job = NULL;
 712
 713                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 714                 if (r < 0)
 715                         return log_error_errno(r, "Failed to stop session scope: %s", bus_error_message(&error, r));
 716
 717                 free(s->scope_job);
 718                 s->scope_job = job;
 719         } else
 720                 s->scope_job = mfree(s->scope_job);
 721
 722         return 0;
 723 }
 724 #else
 725 static int session_stop_cgroup(Session *s, bool force) {
 726         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 727         int r;
 728
 729         assert(s);
 730
 731         if (force || manager_shall_kill(s->manager, s->user->name)) {
 732                 r = session_kill(s, KILL_ALL, SIGTERM);
 733                 if (r < 0)
 734                         return r;
 735         }
 736
 737         return 0;
 738 }
 739 #endif // 0
 740
 741 int session_stop(Session *s, bool force) {
 742         int r;
 743
 744         assert(s);
 745
 746         if (!s->user)
 747                 return -ESTALE;
 748
 749         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 750
 751         if (s->seat)
 752                 seat_evict_position(s->seat, s);
 753
 754         /* We are going down, don't care about FIFOs anymore */
 755         session_remove_fifo(s);
 756
 757         /* Kill cgroup */
 758 #if 0 /// elogind does not start scopes, but sessions
 759         r = session_stop_scope(s, force);
 760 #else
 761         r = session_stop_cgroup(s, force);
 762 #endif // 0
 763
 764         s->stopping = true;
 765
 766         user_elect_display(s->user);
 767
 768         session_save(s);
 769         user_save(s->user);
 770
 771 #if 1 /// elogind must queue this session again
 772         session_add_to_gc_queue(s);
 773 #endif // 1
 774         return r;
 775 }
 776
 777 int session_finalize(Session *s) {
 778         SessionDevice *sd;
 779
 780         assert(s);
 781
 782         if (!s->user)
 783                 return -ESTALE;
 784
 785         if (s->started)
 786                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 787                            "MESSAGE_ID=" SD_MESSAGE_SESSION_STOP_STR,
 788                            "SESSION_ID=%s", s->id,
 789                            "USER_ID=%s", s->user->name,
 790                            "LEADER="PID_FMT, s->leader,
 791                            LOG_MESSAGE("Removed session %s.", s->id),
 792                            NULL);
 793
 794         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 795
 796         if (s->seat)
 797                 seat_evict_position(s->seat, s);
 798
 799         /* Kill session devices */
 800         while ((sd = hashmap_first(s->devices)))
 801                 session_device_free(sd);
 802
 803         (void) unlink(s->state_file);
 804         session_add_to_gc_queue(s);
 805         user_add_to_gc_queue(s->user);
 806
 807         if (s->started) {
 808                 session_send_signal(s, false);
 809                 s->started = false;
 810         }
 811
 812         if (s->seat) {
 813                 if (s->seat->active == s)
 814                         seat_set_active(s->seat, NULL);
 815
 816                 seat_save(s->seat);
 817         }
 818
 819         user_save(s->user);
 820         user_send_changed(s->user, "Display", NULL);
 821
 822         return 0;
 823 }
 824
 825 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 826         Session *s = userdata;
 827
 828         assert(es);
 829         assert(s);
 830
 831         session_stop(s, false);
 832         return 0;
 833 }
 834
 835 int session_release(Session *s) {
 836         assert(s);
 837
 838         if (!s->started || s->stopping)
 839                 return 0;
 840
 841         if (s->timer_event_source)
 842                 return 0;
 843
 844         return sd_event_add_time(s->manager->event,
 845                                  &s->timer_event_source,
 846                                  CLOCK_MONOTONIC,
 847                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 848                                  release_timeout_callback, s);
 849 }
 850
 851 bool session_is_active(Session *s) {
 852         assert(s);
 853
 854         if (!s->seat)
 855                 return true;
 856
 857         return s->seat->active == s;
 858 }
 859
 860 static int get_tty_atime(const char *tty, usec_t *atime) {
 861         _cleanup_free_ char *p = NULL;
 862         struct stat st;
 863
 864         assert(tty);
 865         assert(atime);
 866
 867         if (!path_is_absolute(tty)) {
 868                 p = strappend("/dev/", tty);
 869                 if (!p)
 870                         return -ENOMEM;
 871
 872                 tty = p;
 873         } else if (!path_startswith(tty, "/dev/"))
 874                 return -ENOENT;
 875
 876         if (lstat(tty, &st) < 0)
 877                 return -errno;
 878
 879         *atime = timespec_load(&st.st_atim);
 880         return 0;
 881 }
 882
 883 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 884         _cleanup_free_ char *p = NULL;
 885         int r;
 886
 887         assert(pid > 0);
 888         assert(atime);
 889
 890         r = get_ctty(pid, NULL, &p);
 891         if (r < 0)
 892                 return r;
 893
 894         return get_tty_atime(p, atime);
 895 }
 896
 897 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 898         usec_t atime = 0, n;
 899         int r;
 900
 901         assert(s);
 902
 903         /* Explicit idle hint is set */
 904         if (s->idle_hint) {
 905                 if (t)
 906                         *t = s->idle_hint_timestamp;
 907
 908                 return s->idle_hint;
 909         }
 910
 911         /* Graphical sessions should really implement a real
 912          * idle hint logic */
 913         if (SESSION_TYPE_IS_GRAPHICAL(s->type))
 914                 goto dont_know;
 915
 916         /* For sessions with an explicitly configured tty, let's check
 917          * its atime */
 918         if (s->tty) {
 919                 r = get_tty_atime(s->tty, &atime);
 920                 if (r >= 0)
 921                         goto found_atime;
 922         }
 923
 924         /* For sessions with a leader but no explicitly configured
 925          * tty, let's check the controlling tty of the leader */
 926         if (s->leader > 0) {
 927                 r = get_process_ctty_atime(s->leader, &atime);
 928                 if (r >= 0)
 929                         goto found_atime;
 930         }
 931
 932 dont_know:
 933         if (t)
 934                 *t = s->idle_hint_timestamp;
 935
 936         return 0;
 937
 938 found_atime:
 939         if (t)
 940                 dual_timestamp_from_realtime(t, atime);
 941
 942         n = now(CLOCK_REALTIME);
 943
 944         if (s->manager->idle_action_usec <= 0)
 945                 return 0;
 946
 947         return atime + s->manager->idle_action_usec <= n;
 948 }
 949
 950 void session_set_idle_hint(Session *s, bool b) {
 951         assert(s);
 952
 953         if (s->idle_hint == b)
 954                 return;
 955
 956         s->idle_hint = b;
 957         dual_timestamp_get(&s->idle_hint_timestamp);
 958
 959         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 960
 961         if (s->seat)
 962                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 963
 964         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 965         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 966 }
 967
 968 int session_get_locked_hint(Session *s) {
 969         assert(s);
 970
 971         return s->locked_hint;
 972 }
 973
 974 void session_set_locked_hint(Session *s, bool b) {
 975         assert(s);
 976
 977         if (s->locked_hint == b)
 978                 return;
 979
 980         s->locked_hint = b;
 981
 982         session_send_changed(s, "LockedHint", NULL);
 983 }
 984
 985 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 986         Session *s = userdata;
 987
 988         assert(s);
 989         assert(s->fifo_fd == fd);
 990
 991         /* EOF on the FIFO means the session died abnormally. */
 992
 993         session_remove_fifo(s);
 994         session_stop(s, false);
 995
 996         return 1;
 997 }
 998
 999 int session_create_fifo(Session *s) {
1000         int r;
1001
1002         assert(s);
1003
1004         /* Create FIFO */
1005         if (!s->fifo_path) {
1006                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
1007                 if (r < 0)
1008                         return r;
1009
1010                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
1011                         return -ENOMEM;
1012
1013                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
1014                         return -errno;
1015         }
1016
1017         /* Open reading side */
1018         if (s->fifo_fd < 0) {
1019                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
1020                 if (s->fifo_fd < 0)
1021                         return -errno;
1022
1023         }
1024
1025         if (!s->fifo_event_source) {
1026                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
1027                 if (r < 0)
1028                         return r;
1029
1030                 /* Let's make sure we noticed dead sessions before we process new bus requests (which might create new
1031                  * sessions). */
1032                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_NORMAL-10);
1033                 if (r < 0)
1034                         return r;
1035         }
1036
1037         /* Open writing side */
1038         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
1039         if (r < 0)
1040                 return -errno;
1041
1042         return r;
1043 }
1044
1045 static void session_remove_fifo(Session *s) {
1046         assert(s);
1047
1048         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
1049         s->fifo_fd = safe_close(s->fifo_fd);
1050
1051         if (s->fifo_path) {
1052                 unlink(s->fifo_path);
1053                 s->fifo_path = mfree(s->fifo_path);
1054         }
1055 }
1056
1057 bool session_check_gc(Session *s, bool drop_not_started) {
1058         assert(s);
1059
1060         if (drop_not_started && !s->started)
1061                 return false;
1062
1063         if (!s->user)
1064                 return false;
1065
1066         if (s->fifo_fd >= 0) {
1067                 if (pipe_eof(s->fifo_fd) <= 0)
1068                         return true;
1069         }
1070
1071 #if 0 /// elogind supports neither scopes nor jobs
1072         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
1073                 return true;
1074
1075         if (s->scope && manager_unit_is_active(s->manager, s->scope))
1076                 return true;
1077 #endif // 0
1078
1079         return false;
1080 }
1081
1082 void session_add_to_gc_queue(Session *s) {
1083         assert(s);
1084
1085         if (s->in_gc_queue)
1086                 return;
1087
1088         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
1089         s->in_gc_queue = true;
1090 }
1091
1092 SessionState session_get_state(Session *s) {
1093         assert(s);
1094
1095         /* always check closing first */
1096         if (s->stopping || s->timer_event_source)
1097                 return SESSION_CLOSING;
1098
1099 #if 0 /// elogind does not support systemd scope_jobs
1100         if (s->scope_job || s->fifo_fd < 0)
1101 #else
1102         if (s->fifo_fd < 0)
1103 #endif // 0
1104                 return SESSION_OPENING;
1105
1106         if (session_is_active(s))
1107                 return SESSION_ACTIVE;
1108
1109         return SESSION_ONLINE;
1110 }
1111
1112 int session_kill(Session *s, KillWho who, int signo) {
1113         assert(s);
1114
1115 #if 0 /// Without direct cgroup support, elogind can not kill sessions
1116         if (!s->scope)
1117                 return -ESRCH;
1118
1119         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
1120 #else
1121         if (who == KILL_LEADER) {
1122                 if (s->leader <= 0)
1123                         return -ESRCH;
1124
1125                 /* FIXME: verify that leader is in cgroup?  */
1126
1127                 if (kill(s->leader, signo) < 0) {
1128                         return log_error_errno(errno, "Failed to kill process leader %d for session %s: %m", s->leader, s->id);
1129                 }
1130                 return 0;
1131         } else
1132                 return cg_kill_recursive (SYSTEMD_CGROUP_CONTROLLER, s->id, signo,
1133                                           CGROUP_IGNORE_SELF | CGROUP_REMOVE,
1134                                           NULL, NULL, NULL);
1135 #endif // 0
1136 }
1137
1138 static int session_open_vt(Session *s) {
1139         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
1140
1141         if (s->vtnr < 1)
1142                 return -ENODEV;
1143
1144         if (s->vtfd >= 0)
1145                 return s->vtfd;
1146
1147         sprintf(path, "/dev/tty%u", s->vtnr);
1148         s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
1149         if (s->vtfd < 0)
1150                 return log_error_errno(s->vtfd, "cannot open VT %s of session %s: %m", path, s->id);
1151
1152         return s->vtfd;
1153 }
1154
1155 int session_prepare_vt(Session *s) {
1156         int vt, r;
1157         struct vt_mode mode = { 0 };
1158
1159         if (s->vtnr < 1)
1160                 return 0;
1161
1162         vt = session_open_vt(s);
1163         if (vt < 0)
1164                 return vt;
1165
1166         r = fchown(vt, s->user->uid, -1);
1167         if (r < 0) {
1168                 r = log_error_errno(errno,
1169                                     "Cannot change owner of /dev/tty%u: %m",
1170                                     s->vtnr);
1171                 goto error;
1172         }
1173
1174         r = ioctl(vt, KDSKBMODE, K_OFF);
1175         if (r < 0) {
1176                 r = log_error_errno(errno,
1177                                     "Cannot set K_OFF on /dev/tty%u: %m",
1178                                     s->vtnr);
1179                 goto error;
1180         }
1181
1182         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1183         if (r < 0) {
1184                 r = log_error_errno(errno,
1185                                     "Cannot set KD_GRAPHICS on /dev/tty%u: %m",
1186                                     s->vtnr);
1187                 goto error;
1188         }
1189
1190         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1191          * So we need a dummy handler here which just acknowledges *all* VT
1192          * switch requests. */
1193         mode.mode = VT_PROCESS;
1194         mode.relsig = SIGRTMIN;
1195         mode.acqsig = SIGRTMIN + 1;
1196         r = ioctl(vt, VT_SETMODE, &mode);
1197         if (r < 0) {
1198                 r = log_error_errno(errno,
1199                                     "Cannot set VT_PROCESS on /dev/tty%u: %m",
1200                                     s->vtnr);
1201                 goto error;
1202         }
1203
1204         return 0;
1205
1206 error:
1207         session_restore_vt(s);
1208         return r;
1209 }
1210
1211 void session_restore_vt(Session *s) {
1212
1213         static const struct vt_mode mode = {
1214                 .mode = VT_AUTO,
1215         };
1216
1217         _cleanup_free_ char *utf8 = NULL;
1218         int vt, kb, old_fd;
1219
1220         /* We need to get a fresh handle to the virtual terminal,
1221          * since the old file-descriptor is potentially in a hung-up
1222          * state after the controlling process exited; we do a
1223          * little dance to avoid having the terminal be available
1224          * for reuse before we've cleaned it up.
1225          */
1226         old_fd = s->vtfd;
1227         s->vtfd = -1;
1228
1229         vt = session_open_vt(s);
1230         safe_close(old_fd);
1231
1232         if (vt < 0)
1233                 return;
1234
1235         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1236
1237         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
1238                 kb = K_UNICODE;
1239         else
1240                 kb = K_XLATE;
1241
1242         (void) ioctl(vt, KDSKBMODE, kb);
1243
1244         (void) ioctl(vt, VT_SETMODE, &mode);
1245         (void) fchown(vt, 0, (gid_t) -1);
1246
1247         s->vtfd = safe_close(s->vtfd);
1248 }
1249
1250 void session_leave_vt(Session *s) {
1251         int r;
1252
1253         assert(s);
1254
1255         /* This is called whenever we get a VT-switch signal from the kernel.
1256          * We acknowledge all of them unconditionally. Note that session are
1257          * free to overwrite those handlers and we only register them for
1258          * sessions with controllers. Legacy sessions are not affected.
1259          * However, if we switch from a non-legacy to a legacy session, we must
1260          * make sure to pause all device before acknowledging the switch. We
1261          * process the real switch only after we are notified via sysfs, so the
1262          * legacy session might have already started using the devices. If we
1263          * don't pause the devices before the switch, we might confuse the
1264          * session we switch to. */
1265
1266         if (s->vtfd < 0)
1267                 return;
1268
1269         session_device_pause_all(s);
1270         r = ioctl(s->vtfd, VT_RELDISP, 1);
1271         if (r < 0)
1272                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1273 }
1274
1275 bool session_is_controller(Session *s, const char *sender) {
1276         assert(s);
1277
1278         return streq_ptr(s->controller, sender);
1279 }
1280
1281 static void session_release_controller(Session *s, bool notify) {
1282         _cleanup_free_ char *name = NULL;
1283         SessionDevice *sd;
1284
1285         if (!s->controller)
1286                 return;
1287
1288         name = s->controller;
1289
1290         /* By resetting the controller before releasing the devices, we won't
1291          * send notification signals. This avoids sending useless notifications
1292          * if the controller is released on disconnects. */
1293         if (!notify)
1294                 s->controller = NULL;
1295
1296         while ((sd = hashmap_first(s->devices)))
1297                 session_device_free(sd);
1298
1299         s->controller = NULL;
1300         s->track = sd_bus_track_unref(s->track);
1301 }
1302
1303 static int on_bus_track(sd_bus_track *track, void *userdata) {
1304         Session *s = userdata;
1305
1306         assert(track);
1307         assert(s);
1308
1309         session_drop_controller(s);
1310
1311         return 0;
1312 }
1313
1314 int session_set_controller(Session *s, const char *sender, bool force, bool prepare) {
1315         _cleanup_free_ char *name = NULL;
1316         int r;
1317
1318         assert(s);
1319         assert(sender);
1320
1321         if (session_is_controller(s, sender))
1322                 return 0;
1323         if (s->controller && !force)
1324                 return -EBUSY;
1325
1326         name = strdup(sender);
1327         if (!name)
1328                 return -ENOMEM;
1329
1330         s->track = sd_bus_track_unref(s->track);
1331         r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
1332         if (r < 0)
1333                 return r;
1334
1335         r = sd_bus_track_add_name(s->track, name);
1336         if (r < 0)
1337                 return r;
1338
1339         /* When setting a session controller, we forcibly mute the VT and set
1340          * it into graphics-mode. Applications can override that by changing
1341          * VT state after calling TakeControl(). However, this serves as a good
1342          * default and well-behaving controllers can now ignore VTs entirely.
1343          * Note that we reset the VT on ReleaseControl() and if the controller
1344          * exits.
1345          * If logind crashes/restarts, we restore the controller during restart
1346          * (without preparing the VT since the controller has probably overridden
1347          * VT state by now) or reset the VT in case it crashed/exited, too. */
1348         if (prepare) {
1349                 r = session_prepare_vt(s);
1350                 if (r < 0) {
1351                         s->track = sd_bus_track_unref(s->track);
1352                         return r;
1353                 }
1354         }
1355
1356         session_release_controller(s, true);
1357         s->controller = name;
1358         name = NULL;
1359         session_save(s);
1360
1361         return 0;
1362 }
1363
1364 void session_drop_controller(Session *s) {
1365         assert(s);
1366
1367         if (!s->controller)
1368                 return;
1369
1370         s->track = sd_bus_track_unref(s->track);
1371         session_release_controller(s, false);
1372         session_save(s);
1373         session_restore_vt(s);
1374 }
1375
1376 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1377         [SESSION_OPENING] = "opening",
1378         [SESSION_ONLINE] = "online",
1379         [SESSION_ACTIVE] = "active",
1380         [SESSION_CLOSING] = "closing"
1381 };
1382
1383 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1384
1385 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1386         [SESSION_UNSPECIFIED] = "unspecified",
1387         [SESSION_TTY] = "tty",
1388         [SESSION_X11] = "x11",
1389         [SESSION_WAYLAND] = "wayland",
1390         [SESSION_MIR] = "mir",
1391         [SESSION_WEB] = "web",
1392 };
1393
1394 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1395
1396 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1397         [SESSION_USER] = "user",
1398         [SESSION_GREETER] = "greeter",
1399         [SESSION_LOCK_SCREEN] = "lock-screen",
1400         [SESSION_BACKGROUND] = "background"
1401 };
1402
1403 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1404
1405 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1406         [KILL_LEADER] = "leader",
1407         [KILL_ALL] = "all"
1408 };
1409
1410 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);