src/login/logind-session.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2011 Lennart Poettering
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <linux/kd.h>
  24 #include <linux/vt.h>
  25 #include <signal.h>
  26 #include <string.h>
  27 #include <sys/ioctl.h>
  28 #include <unistd.h>
  29
  30 #include "sd-messages.h"
  31
  32 #include "alloc-util.h"
  33 #include "audit-util.h"
  34 #include "bus-error.h"
  35 #include "bus-util.h"
  36 #include "escape.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 /// Additional includes needed by elogind
  51 #include "extract-word.h"
  52 #include "process-util.h"
  53
  54 #define RELEASE_USEC (20*USEC_PER_SEC)
  55
  56 static void session_remove_fifo(Session *s);
  57
  58 Session* session_new(Manager *m, const char *id) {
  59         Session *s;
  60
  61         assert(m);
  62         assert(id);
  63         assert(session_id_valid(id));
  64
  65         s = new0(Session, 1);
  66         if (!s)
  67                 return NULL;
  68
  69         s->state_file = strappend("/run/systemd/sessions/", id);
  70         if (!s->state_file)
  71                 return mfree(s);
  72
  73         s->devices = hashmap_new(&devt_hash_ops);
  74         if (!s->devices) {
  75                 free(s->state_file);
  76                 return mfree(s);
  77         }
  78
  79         s->id = basename(s->state_file);
  80
  81         if (hashmap_put(m->sessions, s->id, s) < 0) {
  82                 hashmap_free(s->devices);
  83                 free(s->state_file);
  84                 return mfree(s);
  85         }
  86
  87         s->manager = m;
  88         s->fifo_fd = -1;
  89         s->vtfd = -1;
  90         s->audit_id = AUDIT_SESSION_INVALID;
  91
  92         return s;
  93 }
  94
  95 void session_free(Session *s) {
  96         SessionDevice *sd;
  97
  98         assert(s);
  99
 100         if (s->in_gc_queue)
 101                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
 102
 103         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 104
 105         session_remove_fifo(s);
 106
 107         session_drop_controller(s);
 108
 109         while ((sd = hashmap_first(s->devices)))
 110                 session_device_free(sd);
 111
 112         hashmap_free(s->devices);
 113
 114         if (s->user) {
 115                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 116
 117                 if (s->user->display == s)
 118                         s->user->display = NULL;
 119         }
 120
 121         if (s->seat) {
 122                 if (s->seat->active == s)
 123                         s->seat->active = NULL;
 124                 if (s->seat->pending_switch == s)
 125                         s->seat->pending_switch = NULL;
 126
 127                 seat_evict_position(s->seat, s);
 128                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 129         }
 130
 131         if (s->scope) {
 132                 hashmap_remove(s->manager->session_units, s->scope);
 133                 free(s->scope);
 134         }
 135
 136 #if 0 /// elogind does not support systemd scope_jobs
 137         free(s->scope_job);
 138 #endif // 0
 139
 140         sd_bus_message_unref(s->create_message);
 141
 142         free(s->tty);
 143         free(s->display);
 144         free(s->remote_host);
 145         free(s->remote_user);
 146         free(s->service);
 147         free(s->desktop);
 148
 149         hashmap_remove(s->manager->sessions, s->id);
 150
 151         free(s->state_file);
 152         free(s);
 153 }
 154
 155 void session_set_user(Session *s, User *u) {
 156         assert(s);
 157         assert(!s->user);
 158
 159         s->user = u;
 160         LIST_PREPEND(sessions_by_user, u->sessions, s);
 161 }
 162
 163 static void session_save_devices(Session *s, FILE *f) {
 164         SessionDevice *sd;
 165         Iterator i;
 166
 167         if (!hashmap_isempty(s->devices)) {
 168                 fprintf(f, "DEVICES=");
 169                 HASHMAP_FOREACH(sd, s->devices, i)
 170                         fprintf(f, "%u:%u ", major(sd->dev), minor(sd->dev));
 171                 fprintf(f, "\n");
 172         }
 173 }
 174
 175 int session_save(Session *s) {
 176         _cleanup_free_ char *temp_path = NULL;
 177         _cleanup_fclose_ FILE *f = NULL;
 178         int r = 0;
 179
 180         assert(s);
 181
 182         if (!s->user)
 183                 return -ESTALE;
 184
 185         if (!s->started)
 186                 return 0;
 187
 188         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0, false);
 189         if (r < 0)
 190                 goto fail;
 191
 192         r = fopen_temporary(s->state_file, &f, &temp_path);
 193         if (r < 0)
 194                 goto fail;
 195
 196         assert(s->user);
 197
 198         fchmod(fileno(f), 0644);
 199
 200         fprintf(f,
 201                 "# This is private data. Do not parse.\n"
 202                 "UID="UID_FMT"\n"
 203                 "USER=%s\n"
 204                 "ACTIVE=%i\n"
 205                 "STATE=%s\n"
 206                 "REMOTE=%i\n",
 207                 s->user->uid,
 208                 s->user->name,
 209                 session_is_active(s),
 210                 session_state_to_string(session_get_state(s)),
 211                 s->remote);
 212
 213         if (s->type >= 0)
 214                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 215
 216         if (s->class >= 0)
 217                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 218
 219         if (s->scope)
 220                 fprintf(f, "SCOPE=%s\n", s->scope);
 221 #if 0 /// elogind does not support systemd scope_jobs
 222         if (s->scope_job)
 223                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 224 #endif // 0
 225
 226         if (s->fifo_path)
 227                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 228
 229         if (s->seat)
 230                 fprintf(f, "SEAT=%s\n", s->seat->id);
 231
 232         if (s->tty)
 233                 fprintf(f, "TTY=%s\n", s->tty);
 234
 235         if (s->display)
 236                 fprintf(f, "DISPLAY=%s\n", s->display);
 237
 238         if (s->remote_host) {
 239                 _cleanup_free_ char *escaped;
 240
 241                 escaped = cescape(s->remote_host);
 242                 if (!escaped) {
 243                         r = -ENOMEM;
 244                         goto fail;
 245                 }
 246
 247                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 248         }
 249
 250         if (s->remote_user) {
 251                 _cleanup_free_ char *escaped;
 252
 253                 escaped = cescape(s->remote_user);
 254                 if (!escaped) {
 255                         r = -ENOMEM;
 256                         goto fail;
 257                 }
 258
 259                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 260         }
 261
 262         if (s->service) {
 263                 _cleanup_free_ char *escaped;
 264
 265                 escaped = cescape(s->service);
 266                 if (!escaped) {
 267                         r = -ENOMEM;
 268                         goto fail;
 269                 }
 270
 271                 fprintf(f, "SERVICE=%s\n", escaped);
 272         }
 273
 274         if (s->desktop) {
 275                 _cleanup_free_ char *escaped;
 276
 277
 278                 escaped = cescape(s->desktop);
 279                 if (!escaped) {
 280                         r = -ENOMEM;
 281                         goto fail;
 282                 }
 283
 284                 fprintf(f, "DESKTOP=%s\n", escaped);
 285         }
 286
 287         if (s->seat && seat_has_vts(s->seat))
 288                 fprintf(f, "VTNR=%u\n", s->vtnr);
 289
 290         if (!s->vtnr)
 291                 fprintf(f, "POSITION=%u\n", s->position);
 292
 293         if (pid_is_valid(s->leader))
 294                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 295
 296         if (audit_session_is_valid(s->audit_id))
 297                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 298
 299         if (dual_timestamp_is_set(&s->timestamp))
 300                 fprintf(f,
 301                         "REALTIME="USEC_FMT"\n"
 302                         "MONOTONIC="USEC_FMT"\n",
 303                         s->timestamp.realtime,
 304                         s->timestamp.monotonic);
 305
 306         if (s->controller) {
 307                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 308                 session_save_devices(s, f);
 309         }
 310
 311         r = fflush_and_check(f);
 312         if (r < 0)
 313                 goto fail;
 314
 315         if (rename(temp_path, s->state_file) < 0) {
 316                 r = -errno;
 317                 goto fail;
 318         }
 319
 320         return 0;
 321
 322 fail:
 323         (void) unlink(s->state_file);
 324
 325         if (temp_path)
 326                 (void) unlink(temp_path);
 327
 328         return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 329 }
 330
 331 static int session_load_devices(Session *s, const char *devices) {
 332         const char *p;
 333         int r = 0;
 334
 335         assert(s);
 336
 337         for (p = devices;;) {
 338                 _cleanup_free_ char *word = NULL;
 339                 SessionDevice *sd;
 340                 dev_t dev;
 341                 int k;
 342
 343                 k = extract_first_word(&p, &word, NULL, 0);
 344                 if (k == 0)
 345                         break;
 346                 if (k < 0) {
 347                         r = k;
 348                         break;
 349                 }
 350
 351                 k = parse_dev(word, &dev);
 352                 if (k < 0) {
 353                         r = k;
 354                         continue;
 355                 }
 356
 357                 /* The file descriptors for loaded devices will be reattached later. */
 358                 k = session_device_new(s, dev, false, &sd);
 359                 if (k < 0)
 360                         r = k;
 361         }
 362
 363         if (r < 0)
 364                 log_error_errno(r, "Loading session devices for session %s failed: %m", s->id);
 365
 366         return r;
 367 }
 368
 369 int session_load(Session *s) {
 370         _cleanup_free_ char *remote = NULL,
 371                 *seat = NULL,
 372                 *vtnr = NULL,
 373                 *state = NULL,
 374                 *position = NULL,
 375                 *leader = NULL,
 376                 *type = NULL,
 377                 *class = NULL,
 378                 *uid = NULL,
 379                 *realtime = NULL,
 380                 *monotonic = NULL,
 381                 *controller = NULL,
 382                 *active = NULL,
 383                 *devices = NULL;
 384
 385         int k, r;
 386
 387         assert(s);
 388
 389         r = parse_env_file(s->state_file, NEWLINE,
 390                            "REMOTE",         &remote,
 391                            "SCOPE",          &s->scope,
 392 #if 0 /// elogind does not support systemd scope_jobs
 393                            "SCOPE_JOB",      &s->scope_job,
 394 #endif // 0
 395                            "FIFO",           &s->fifo_path,
 396                            "SEAT",           &seat,
 397                            "TTY",            &s->tty,
 398                            "DISPLAY",        &s->display,
 399                            "REMOTE_HOST",    &s->remote_host,
 400                            "REMOTE_USER",    &s->remote_user,
 401                            "SERVICE",        &s->service,
 402                            "DESKTOP",        &s->desktop,
 403                            "VTNR",           &vtnr,
 404                            "STATE",          &state,
 405                            "POSITION",       &position,
 406                            "LEADER",         &leader,
 407                            "TYPE",           &type,
 408                            "CLASS",          &class,
 409                            "UID",            &uid,
 410                            "REALTIME",       &realtime,
 411                            "MONOTONIC",      &monotonic,
 412                            "CONTROLLER",     &controller,
 413                            "ACTIVE",         &active,
 414                            "DEVICES",        &devices,
 415                            NULL);
 416
 417         if (r < 0)
 418                 return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 419
 420         if (!s->user) {
 421                 uid_t u;
 422                 User *user;
 423
 424                 if (!uid) {
 425                         log_error("UID not specified for session %s", s->id);
 426                         return -ENOENT;
 427                 }
 428
 429                 r = parse_uid(uid, &u);
 430                 if (r < 0)  {
 431                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 432                         return r;
 433                 }
 434
 435                 user = hashmap_get(s->manager->users, UID_TO_PTR(u));
 436                 if (!user) {
 437                         log_error("User of session %s not known.", s->id);
 438                         return -ENOENT;
 439                 }
 440
 441                 session_set_user(s, user);
 442         }
 443
 444         if (remote) {
 445                 k = parse_boolean(remote);
 446                 if (k >= 0)
 447                         s->remote = k;
 448         }
 449
 450         if (vtnr)
 451                 safe_atou(vtnr, &s->vtnr);
 452
 453         if (seat && !s->seat) {
 454                 Seat *o;
 455
 456                 o = hashmap_get(s->manager->seats, seat);
 457                 if (o)
 458                         r = seat_attach_session(o, s);
 459                 if (!o || r < 0)
 460                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 461         }
 462
 463         if (!s->seat || !seat_has_vts(s->seat))
 464                 s->vtnr = 0;
 465
 466         if (position && s->seat) {
 467                 unsigned int npos;
 468
 469                 safe_atou(position, &npos);
 470                 seat_claim_position(s->seat, s, npos);
 471         }
 472
 473         if (leader) {
 474                 if (parse_pid(leader, &s->leader) >= 0)
 475                         (void) audit_session_from_pid(s->leader, &s->audit_id);
 476         }
 477
 478         if (type) {
 479                 SessionType t;
 480
 481                 t = session_type_from_string(type);
 482                 if (t >= 0)
 483                         s->type = t;
 484         }
 485
 486         if (class) {
 487                 SessionClass c;
 488
 489                 c = session_class_from_string(class);
 490                 if (c >= 0)
 491                         s->class = c;
 492         }
 493
 494         if (state && streq(state, "closing"))
 495                 s->stopping = true;
 496
 497         if (s->fifo_path) {
 498                 int fd;
 499
 500                 /* If we open an unopened pipe for reading we will not
 501                    get an EOF. to trigger an EOF we hence open it for
 502                    writing, but close it right away which then will
 503                    trigger the EOF. This will happen immediately if no
 504                    other process has the FIFO open for writing, i. e.
 505                    when the session died before logind (re)started. */
 506
 507                 fd = session_create_fifo(s);
 508                 safe_close(fd);
 509         }
 510
 511         if (realtime)
 512                 timestamp_deserialize(realtime, &s->timestamp.realtime);
 513         if (monotonic)
 514                 timestamp_deserialize(monotonic, &s->timestamp.monotonic);
 515
 516         if (active) {
 517                 k = parse_boolean(active);
 518                 if (k >= 0)
 519                         s->was_active = k;
 520         }
 521
 522         if (controller) {
 523                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0) {
 524                         session_set_controller(s, controller, false, false);
 525                         session_load_devices(s, devices);
 526                 } else
 527                         session_restore_vt(s);
 528         }
 529
 530         return r;
 531 }
 532
 533 int session_activate(Session *s) {
 534         unsigned int num_pending;
 535
 536         assert(s);
 537         assert(s->user);
 538
 539         if (!s->seat)
 540                 return -EOPNOTSUPP;
 541
 542         if (s->seat->active == s)
 543                 return 0;
 544
 545         /* on seats with VTs, we let VTs manage session-switching */
 546         if (seat_has_vts(s->seat)) {
 547                 if (!s->vtnr)
 548                         return -EOPNOTSUPP;
 549
 550                 return chvt(s->vtnr);
 551         }
 552
 553         /* On seats without VTs, we implement session-switching in logind. We
 554          * try to pause all session-devices and wait until the session
 555          * controller acknowledged them. Once all devices are asleep, we simply
 556          * switch the active session and be done.
 557          * We save the session we want to switch to in seat->pending_switch and
 558          * seat_complete_switch() will perform the final switch. */
 559
 560         s->seat->pending_switch = s;
 561
 562         /* if no devices are running, immediately perform the session switch */
 563         num_pending = session_device_try_pause_all(s);
 564         if (!num_pending)
 565                 seat_complete_switch(s->seat);
 566
 567         return 0;
 568 }
 569
 570 #if 0 /// UNNEEDED by elogind
 571 static int session_start_scope(Session *s) {
 572         int r;
 573
 574         assert(s);
 575         assert(s->user);
 576
 577         if (!s->scope) {
 578                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 579                 char *scope, *job = NULL;
 580                 const char *description;
 581
 582                 scope = strjoin("session-", s->id, ".scope");
 583                 if (!scope)
 584                         return log_oom();
 585
 586                 description = strjoina("Session ", s->id, " of user ", s->user->name);
 587
 588                 r = manager_start_scope(
 589                                 s->manager,
 590                                 scope,
 591                                 s->leader,
 592                                 s->user->slice,
 593                                 description,
 594                                 "systemd-logind.service",
 595                                 "systemd-user-sessions.service",
 596                                 (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */
 597                                 &error,
 598                                 &job);
 599                 if (r < 0) {
 600                         log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));
 601                         free(scope);
 602                         return r;
 603                 } else {
 604                         s->scope = scope;
 605
 606                         free(s->scope_job);
 607                         s->scope_job = job;
 608                 }
 609         }
 610
 611         if (s->scope)
 612                 (void) hashmap_put(s->manager->session_units, s->scope, s);
 613
 614         return 0;
 615 }
 616 #else
 617 static int session_start_cgroup(Session *s) {
 618         int r;
 619
 620         assert(s);
 621         assert(s->user);
 622         assert(s->leader > 0);
 623
 624         /* First, create our own group */
 625         r = cg_create(SYSTEMD_CGROUP_CONTROLLER, s->id);
 626         if (r < 0)
 627                 return log_error_errno(r, "Failed to create cgroup %s: %m", s->id);
 628
 629         r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, s->id, s->leader);
 630         if (r < 0)
 631                 log_warning_errno(r, "Failed to attach PID %d to cgroup %s: %m", s->leader, s->id);
 632
 633         return 0;
 634 }
 635 #endif // 0
 636
 637 int session_start(Session *s) {
 638         int r;
 639
 640         assert(s);
 641
 642         if (!s->user)
 643                 return -ESTALE;
 644
 645         if (s->started)
 646                 return 0;
 647
 648         r = user_start(s->user);
 649         if (r < 0)
 650                 return r;
 651
 652         /* Create cgroup */
 653 #if 0 /// elogind does its own session management
 654         r = session_start_scope(s);
 655 #else
 656         r = session_start_cgroup(s);
 657 #endif // 0
 658         if (r < 0)
 659                 return r;
 660
 661         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 662                    "MESSAGE_ID=" SD_MESSAGE_SESSION_START_STR,
 663                    "SESSION_ID=%s", s->id,
 664                    "USER_ID=%s", s->user->name,
 665                    "LEADER="PID_FMT, s->leader,
 666                    LOG_MESSAGE("New session %s of user %s.", s->id, s->user->name),
 667                    NULL);
 668
 669         if (!dual_timestamp_is_set(&s->timestamp))
 670                 dual_timestamp_get(&s->timestamp);
 671
 672         if (s->seat)
 673                 seat_read_active_vt(s->seat);
 674
 675         s->started = true;
 676
 677         user_elect_display(s->user);
 678
 679         /* Save data */
 680         session_save(s);
 681         user_save(s->user);
 682         if (s->seat)
 683                 seat_save(s->seat);
 684
 685         /* Send signals */
 686         session_send_signal(s, true);
 687         user_send_changed(s->user, "Display", NULL);
 688         if (s->seat) {
 689                 if (s->seat->active == s)
 690                         seat_send_changed(s->seat, "ActiveSession", NULL);
 691         }
 692
 693         return 0;
 694 }
 695
 696 #if 0 /// UNNEEDED by elogind
 697 static int session_stop_scope(Session *s, bool force) {
 698         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 699         int r;
 700
 701         assert(s);
 702
 703         if (!s->scope)
 704                 return 0;
 705
 706         /* Let's always abandon the scope first. This tells systemd that we are not interested anymore, and everything
 707          * that is left in the scope is "left-over". Informing systemd about this has the benefit that it will log
 708          * when killing any processes left after this point. */
 709         r = manager_abandon_scope(s->manager, s->scope, &error);
 710         if (r < 0)
 711                 log_warning_errno(r, "Failed to abandon session scope, ignoring: %s", bus_error_message(&error, r));
 712
 713         /* Optionally, let's kill everything that's left now. */
 714         if (force || manager_shall_kill(s->manager, s->user->name)) {
 715                 char *job = NULL;
 716
 717                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 718                 if (r < 0)
 719                         return log_error_errno(r, "Failed to stop session scope: %s", bus_error_message(&error, r));
 720
 721                 free(s->scope_job);
 722                 s->scope_job = job;
 723         } else
 724                 s->scope_job = mfree(s->scope_job);
 725
 726         return 0;
 727 }
 728 #else
 729 static int session_stop_cgroup(Session *s, bool force) {
 730         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 731         int r;
 732
 733         assert(s);
 734
 735 #if 0 /// elogind must not kill lingering user processes alive
 736         if (force || manager_shall_kill(s->manager, s->user->name)) {
 737 #else
 738         if ( (force || manager_shall_kill(s->manager, s->user->name) )
 739             && (user_check_linger_file(s->user) < 1) ) {
 740 #endif // 1
 741
 742                 r = session_kill(s, KILL_ALL, SIGTERM);
 743                 if (r < 0)
 744                         return r;
 745         }
 746
 747         return 0;
 748 }
 749 #endif // 0
 750
 751 int session_stop(Session *s, bool force) {
 752         int r;
 753
 754         assert(s);
 755
 756         if (!s->user)
 757                 return -ESTALE;
 758
 759         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 760
 761         if (s->seat)
 762                 seat_evict_position(s->seat, s);
 763
 764         /* We are going down, don't care about FIFOs anymore */
 765         session_remove_fifo(s);
 766
 767         /* Kill cgroup */
 768 #if 0 /// elogind does not start scopes, but sessions
 769         r = session_stop_scope(s, force);
 770 #else
 771         r = session_stop_cgroup(s, force);
 772 #endif // 0
 773
 774         s->stopping = true;
 775
 776         user_elect_display(s->user);
 777
 778         session_save(s);
 779         user_save(s->user);
 780
 781 #if 1 /// elogind must queue this session again
 782         session_add_to_gc_queue(s);
 783 #endif // 1
 784         return r;
 785 }
 786
 787 int session_finalize(Session *s) {
 788         SessionDevice *sd;
 789
 790         assert(s);
 791
 792         if (!s->user)
 793                 return -ESTALE;
 794
 795         if (s->started)
 796                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 797                            "MESSAGE_ID=" SD_MESSAGE_SESSION_STOP_STR,
 798                            "SESSION_ID=%s", s->id,
 799                            "USER_ID=%s", s->user->name,
 800                            "LEADER="PID_FMT, s->leader,
 801                            LOG_MESSAGE("Removed session %s.", s->id),
 802                            NULL);
 803
 804         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 805
 806         if (s->seat)
 807                 seat_evict_position(s->seat, s);
 808
 809         /* Kill session devices */
 810         while ((sd = hashmap_first(s->devices)))
 811                 session_device_free(sd);
 812
 813         (void) unlink(s->state_file);
 814         session_add_to_gc_queue(s);
 815         user_add_to_gc_queue(s->user);
 816
 817         if (s->started) {
 818                 session_send_signal(s, false);
 819                 s->started = false;
 820         }
 821
 822         if (s->seat) {
 823                 if (s->seat->active == s)
 824                         seat_set_active(s->seat, NULL);
 825
 826                 seat_save(s->seat);
 827         }
 828
 829         user_save(s->user);
 830         user_send_changed(s->user, "Display", NULL);
 831
 832         return 0;
 833 }
 834
 835 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 836         Session *s = userdata;
 837
 838         assert(es);
 839         assert(s);
 840
 841         session_stop(s, false);
 842         return 0;
 843 }
 844
 845 int session_release(Session *s) {
 846         assert(s);
 847
 848         if (!s->started || s->stopping)
 849                 return 0;
 850
 851         if (s->timer_event_source)
 852                 return 0;
 853
 854         return sd_event_add_time(s->manager->event,
 855                                  &s->timer_event_source,
 856                                  CLOCK_MONOTONIC,
 857                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 858                                  release_timeout_callback, s);
 859 }
 860
 861 bool session_is_active(Session *s) {
 862         assert(s);
 863
 864         if (!s->seat)
 865                 return true;
 866
 867         return s->seat->active == s;
 868 }
 869
 870 static int get_tty_atime(const char *tty, usec_t *atime) {
 871         _cleanup_free_ char *p = NULL;
 872         struct stat st;
 873
 874         assert(tty);
 875         assert(atime);
 876
 877         if (!path_is_absolute(tty)) {
 878                 p = strappend("/dev/", tty);
 879                 if (!p)
 880                         return -ENOMEM;
 881
 882                 tty = p;
 883         } else if (!path_startswith(tty, "/dev/"))
 884                 return -ENOENT;
 885
 886         if (lstat(tty, &st) < 0)
 887                 return -errno;
 888
 889         *atime = timespec_load(&st.st_atim);
 890         return 0;
 891 }
 892
 893 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 894         _cleanup_free_ char *p = NULL;
 895         int r;
 896
 897         assert(pid > 0);
 898         assert(atime);
 899
 900         r = get_ctty(pid, NULL, &p);
 901         if (r < 0)
 902                 return r;
 903
 904         return get_tty_atime(p, atime);
 905 }
 906
 907 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 908         usec_t atime = 0, n;
 909         int r;
 910
 911         assert(s);
 912
 913         /* Explicit idle hint is set */
 914         if (s->idle_hint) {
 915                 if (t)
 916                         *t = s->idle_hint_timestamp;
 917
 918                 return s->idle_hint;
 919         }
 920
 921         /* Graphical sessions should really implement a real
 922          * idle hint logic */
 923         if (SESSION_TYPE_IS_GRAPHICAL(s->type))
 924                 goto dont_know;
 925
 926         /* For sessions with an explicitly configured tty, let's check
 927          * its atime */
 928         if (s->tty) {
 929                 r = get_tty_atime(s->tty, &atime);
 930                 if (r >= 0)
 931                         goto found_atime;
 932         }
 933
 934         /* For sessions with a leader but no explicitly configured
 935          * tty, let's check the controlling tty of the leader */
 936         if (s->leader > 0) {
 937                 r = get_process_ctty_atime(s->leader, &atime);
 938                 if (r >= 0)
 939                         goto found_atime;
 940         }
 941
 942 dont_know:
 943         if (t)
 944                 *t = s->idle_hint_timestamp;
 945
 946         return 0;
 947
 948 found_atime:
 949         if (t)
 950                 dual_timestamp_from_realtime(t, atime);
 951
 952         n = now(CLOCK_REALTIME);
 953
 954         if (s->manager->idle_action_usec <= 0)
 955                 return 0;
 956
 957         return atime + s->manager->idle_action_usec <= n;
 958 }
 959
 960 void session_set_idle_hint(Session *s, bool b) {
 961         assert(s);
 962
 963         if (s->idle_hint == b)
 964                 return;
 965
 966         s->idle_hint = b;
 967         dual_timestamp_get(&s->idle_hint_timestamp);
 968
 969         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 970
 971         if (s->seat)
 972                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 973
 974         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 975         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 976 }
 977
 978 int session_get_locked_hint(Session *s) {
 979         assert(s);
 980
 981         return s->locked_hint;
 982 }
 983
 984 void session_set_locked_hint(Session *s, bool b) {
 985         assert(s);
 986
 987         if (s->locked_hint == b)
 988                 return;
 989
 990         s->locked_hint = b;
 991
 992         session_send_changed(s, "LockedHint", NULL);
 993 }
 994
 995 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 996         Session *s = userdata;
 997
 998         assert(s);
 999         assert(s->fifo_fd == fd);
1000
1001         /* EOF on the FIFO means the session died abnormally. */
1002
1003         session_remove_fifo(s);
1004         session_stop(s, false);
1005
1006         return 1;
1007 }
1008
1009 int session_create_fifo(Session *s) {
1010         int r;
1011
1012         assert(s);
1013
1014         /* Create FIFO */
1015         if (!s->fifo_path) {
1016                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0, false);
1017                 if (r < 0)
1018                         return r;
1019
1020                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
1021                         return -ENOMEM;
1022
1023                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
1024                         return -errno;
1025         }
1026
1027         /* Open reading side */
1028         if (s->fifo_fd < 0) {
1029                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
1030                 if (s->fifo_fd < 0)
1031                         return -errno;
1032
1033         }
1034
1035         if (!s->fifo_event_source) {
1036                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
1037                 if (r < 0)
1038                         return r;
1039
1040                 /* Let's make sure we noticed dead sessions before we process new bus requests (which might create new
1041                  * sessions). */
1042                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_NORMAL-10);
1043                 if (r < 0)
1044                         return r;
1045         }
1046
1047         /* Open writing side */
1048         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NONBLOCK);
1049         if (r < 0)
1050                 return -errno;
1051
1052         return r;
1053 }
1054
1055 static void session_remove_fifo(Session *s) {
1056         assert(s);
1057
1058         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
1059         s->fifo_fd = safe_close(s->fifo_fd);
1060
1061         if (s->fifo_path) {
1062                 unlink(s->fifo_path);
1063                 s->fifo_path = mfree(s->fifo_path);
1064         }
1065 }
1066
1067 bool session_may_gc(Session *s, bool drop_not_started) {
1068         assert(s);
1069
1070         if (drop_not_started && !s->started)
1071                 return true;
1072
1073         if (!s->user)
1074                 return true;
1075
1076         if (s->fifo_fd >= 0) {
1077                 if (pipe_eof(s->fifo_fd) <= 0)
1078                         return false;
1079         }
1080
1081 #if 0 /// elogind supports neither scopes nor jobs
1082         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
1083                 return false;
1084
1085         if (s->scope && manager_unit_is_active(s->manager, s->scope))
1086 #endif // 0
1087                 return false;
1088
1089         return true;
1090 }
1091
1092 void session_add_to_gc_queue(Session *s) {
1093         assert(s);
1094
1095         if (s->in_gc_queue)
1096                 return;
1097
1098         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
1099         s->in_gc_queue = true;
1100 }
1101
1102 SessionState session_get_state(Session *s) {
1103         assert(s);
1104
1105         /* always check closing first */
1106         if (s->stopping || s->timer_event_source)
1107                 return SESSION_CLOSING;
1108
1109 #if 0 /// elogind does not support systemd scope_jobs
1110         if (s->scope_job || s->fifo_fd < 0)
1111 #else
1112         if (s->fifo_fd < 0)
1113 #endif // 0
1114                 return SESSION_OPENING;
1115
1116         if (session_is_active(s))
1117                 return SESSION_ACTIVE;
1118
1119         return SESSION_ONLINE;
1120 }
1121
1122 int session_kill(Session *s, KillWho who, int signo) {
1123         assert(s);
1124
1125 #if 0 /// Without direct cgroup support, elogind can not kill sessions
1126         if (!s->scope)
1127                 return -ESRCH;
1128
1129         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
1130 #else
1131         if (who == KILL_LEADER) {
1132                 if (s->leader <= 0)
1133                         return -ESRCH;
1134
1135                 /* FIXME: verify that leader is in cgroup?  */
1136
1137                 if (kill(s->leader, signo) < 0) {
1138                         return log_error_errno(errno, "Failed to kill process leader %d for session %s: %m", s->leader, s->id);
1139                 }
1140                 return 0;
1141         } else
1142                 return cg_kill_recursive (SYSTEMD_CGROUP_CONTROLLER, s->id, signo,
1143                                           CGROUP_IGNORE_SELF | CGROUP_REMOVE,
1144                                           NULL, NULL, NULL);
1145 #endif // 0
1146 }
1147
1148 static int session_open_vt(Session *s) {
1149         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
1150
1151         if (s->vtnr < 1)
1152                 return -ENODEV;
1153
1154         if (s->vtfd >= 0)
1155                 return s->vtfd;
1156
1157         sprintf(path, "/dev/tty%u", s->vtnr);
1158         s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
1159         if (s->vtfd < 0)
1160                 return log_error_errno(s->vtfd, "cannot open VT %s of session %s: %m", path, s->id);
1161
1162         return s->vtfd;
1163 }
1164
1165 int session_prepare_vt(Session *s) {
1166         int vt, r;
1167         struct vt_mode mode = { 0 };
1168
1169         if (s->vtnr < 1)
1170                 return 0;
1171
1172         vt = session_open_vt(s);
1173         if (vt < 0)
1174                 return vt;
1175
1176         r = fchown(vt, s->user->uid, -1);
1177         if (r < 0) {
1178                 r = log_error_errno(errno,
1179                                     "Cannot change owner of /dev/tty%u: %m",
1180                                     s->vtnr);
1181                 goto error;
1182         }
1183
1184         r = ioctl(vt, KDSKBMODE, K_OFF);
1185         if (r < 0) {
1186                 r = log_error_errno(errno,
1187                                     "Cannot set K_OFF on /dev/tty%u: %m",
1188                                     s->vtnr);
1189                 goto error;
1190         }
1191
1192         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1193         if (r < 0) {
1194                 r = log_error_errno(errno,
1195                                     "Cannot set KD_GRAPHICS on /dev/tty%u: %m",
1196                                     s->vtnr);
1197                 goto error;
1198         }
1199
1200         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1201          * So we need a dummy handler here which just acknowledges *all* VT
1202          * switch requests. */
1203         mode.mode = VT_PROCESS;
1204         mode.relsig = SIGRTMIN;
1205         mode.acqsig = SIGRTMIN + 1;
1206         r = ioctl(vt, VT_SETMODE, &mode);
1207         if (r < 0) {
1208                 r = log_error_errno(errno,
1209                                     "Cannot set VT_PROCESS on /dev/tty%u: %m",
1210                                     s->vtnr);
1211                 goto error;
1212         }
1213
1214         return 0;
1215
1216 error:
1217         session_restore_vt(s);
1218         return r;
1219 }
1220
1221 void session_restore_vt(Session *s) {
1222
1223         static const struct vt_mode mode = {
1224                 .mode = VT_AUTO,
1225         };
1226
1227         int vt, old_fd;
1228
1229         /* We need to get a fresh handle to the virtual terminal,
1230          * since the old file-descriptor is potentially in a hung-up
1231          * state after the controlling process exited; we do a
1232          * little dance to avoid having the terminal be available
1233          * for reuse before we've cleaned it up.
1234          */
1235         old_fd = s->vtfd;
1236         s->vtfd = -1;
1237
1238         vt = session_open_vt(s);
1239         safe_close(old_fd);
1240
1241         if (vt < 0)
1242                 return;
1243
1244         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1245
1246         (void) vt_reset_keyboard(vt);
1247
1248         (void) ioctl(vt, VT_SETMODE, &mode);
1249         (void) fchown(vt, 0, (gid_t) -1);
1250
1251         s->vtfd = safe_close(s->vtfd);
1252 }
1253
1254 void session_leave_vt(Session *s) {
1255         int r;
1256
1257         assert(s);
1258
1259         /* This is called whenever we get a VT-switch signal from the kernel.
1260          * We acknowledge all of them unconditionally. Note that session are
1261          * free to overwrite those handlers and we only register them for
1262          * sessions with controllers. Legacy sessions are not affected.
1263          * However, if we switch from a non-legacy to a legacy session, we must
1264          * make sure to pause all device before acknowledging the switch. We
1265          * process the real switch only after we are notified via sysfs, so the
1266          * legacy session might have already started using the devices. If we
1267          * don't pause the devices before the switch, we might confuse the
1268          * session we switch to. */
1269
1270         if (s->vtfd < 0)
1271                 return;
1272
1273         session_device_pause_all(s);
1274         r = ioctl(s->vtfd, VT_RELDISP, 1);
1275         if (r < 0)
1276                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1277 }
1278
1279 bool session_is_controller(Session *s, const char *sender) {
1280         assert(s);
1281
1282         return streq_ptr(s->controller, sender);
1283 }
1284
1285 static void session_release_controller(Session *s, bool notify) {
1286         _cleanup_free_ char *name = NULL;
1287         SessionDevice *sd;
1288
1289         if (!s->controller)
1290                 return;
1291
1292         name = s->controller;
1293
1294         /* By resetting the controller before releasing the devices, we won't
1295          * send notification signals. This avoids sending useless notifications
1296          * if the controller is released on disconnects. */
1297         if (!notify)
1298                 s->controller = NULL;
1299
1300         while ((sd = hashmap_first(s->devices)))
1301                 session_device_free(sd);
1302
1303         s->controller = NULL;
1304         s->track = sd_bus_track_unref(s->track);
1305 }
1306
1307 static int on_bus_track(sd_bus_track *track, void *userdata) {
1308         Session *s = userdata;
1309
1310         assert(track);
1311         assert(s);
1312
1313         session_drop_controller(s);
1314
1315         return 0;
1316 }
1317
1318 int session_set_controller(Session *s, const char *sender, bool force, bool prepare) {
1319         _cleanup_free_ char *name = NULL;
1320         int r;
1321
1322         assert(s);
1323         assert(sender);
1324
1325         if (session_is_controller(s, sender))
1326                 return 0;
1327         if (s->controller && !force)
1328                 return -EBUSY;
1329
1330         name = strdup(sender);
1331         if (!name)
1332                 return -ENOMEM;
1333
1334         s->track = sd_bus_track_unref(s->track);
1335         r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
1336         if (r < 0)
1337                 return r;
1338
1339         r = sd_bus_track_add_name(s->track, name);
1340         if (r < 0)
1341                 return r;
1342
1343         /* When setting a session controller, we forcibly mute the VT and set
1344          * it into graphics-mode. Applications can override that by changing
1345          * VT state after calling TakeControl(). However, this serves as a good
1346          * default and well-behaving controllers can now ignore VTs entirely.
1347          * Note that we reset the VT on ReleaseControl() and if the controller
1348          * exits.
1349          * If logind crashes/restarts, we restore the controller during restart
1350          * (without preparing the VT since the controller has probably overridden
1351          * VT state by now) or reset the VT in case it crashed/exited, too. */
1352         if (prepare) {
1353                 r = session_prepare_vt(s);
1354                 if (r < 0) {
1355                         s->track = sd_bus_track_unref(s->track);
1356                         return r;
1357                 }
1358         }
1359
1360         session_release_controller(s, true);
1361         s->controller = name;
1362         name = NULL;
1363         session_save(s);
1364
1365         return 0;
1366 }
1367
1368 void session_drop_controller(Session *s) {
1369         assert(s);
1370
1371         if (!s->controller)
1372                 return;
1373
1374         s->track = sd_bus_track_unref(s->track);
1375         session_release_controller(s, false);
1376         session_save(s);
1377         session_restore_vt(s);
1378 }
1379
1380 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1381         [SESSION_OPENING] = "opening",
1382         [SESSION_ONLINE] = "online",
1383         [SESSION_ACTIVE] = "active",
1384         [SESSION_CLOSING] = "closing"
1385 };
1386
1387 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1388
1389 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1390         [SESSION_UNSPECIFIED] = "unspecified",
1391         [SESSION_TTY] = "tty",
1392         [SESSION_X11] = "x11",
1393         [SESSION_WAYLAND] = "wayland",
1394         [SESSION_MIR] = "mir",
1395         [SESSION_WEB] = "web",
1396 };
1397
1398 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1399
1400 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1401         [SESSION_USER] = "user",
1402         [SESSION_GREETER] = "greeter",
1403         [SESSION_LOCK_SCREEN] = "lock-screen",
1404         [SESSION_BACKGROUND] = "background"
1405 };
1406
1407 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1408
1409 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1410         [KILL_LEADER] = "leader",
1411         [KILL_ALL] = "all"
1412 };
1413
1414 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);