src/login/logind-user.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 <string.h>
  22 #include <sys/mount.h>
  23 #include <unistd.h>
  24
  25 #include "alloc-util.h"
  26 #include "bus-common-errors.h"
  27 #include "bus-error.h"
  28 #include "bus-util.h"
  29 #include "clean-ipc.h"
  30 #include "conf-parser.h"
  31 #include "escape.h"
  32 #include "fd-util.h"
  33 #include "fileio.h"
  34 #include "formats-util.h"
  35 #include "fs-util.h"
  36 #include "hashmap.h"
  37 #include "label.h"
  38 #include "logind-user.h"
  39 #include "mkdir.h"
  40 #include "mount-util.h"
  41 #include "parse-util.h"
  42 #include "path-util.h"
  43 #include "rm-rf.h"
  44 #include "smack-util.h"
  45 #include "special.h"
  46 #include "stdio-util.h"
  47 #include "string-table.h"
  48 #include "unit-name.h"
  49 #include "user-util.h"
  50 #include "util.h"
  51
  52 int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
  53         _cleanup_(user_freep) User *u = NULL;
  54         char lu[DECIMAL_STR_MAX(uid_t) + 1];
  55         int r;
  56
  57         assert(out);
  58         assert(m);
  59         assert(name);
  60
  61         u = new0(User, 1);
  62         if (!u)
  63                 return -ENOMEM;
  64
  65         u->manager = m;
  66         u->uid = uid;
  67         u->gid = gid;
  68         xsprintf(lu, UID_FMT, uid);
  69
  70         u->name = strdup(name);
  71         if (!u->name)
  72                 return -ENOMEM;
  73
  74         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  75                 return -ENOMEM;
  76
  77         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  78                 return -ENOMEM;
  79
  80         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  81         if (r < 0)
  82                 return r;
  83
  84         r = unit_name_build("user", lu, ".service", &u->service);
  85         if (r < 0)
  86                 return r;
  87
  88         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  89         if (r < 0)
  90                 return r;
  91
  92         r = hashmap_put(m->user_units, u->slice, u);
  93         if (r < 0)
  94                 return r;
  95
  96         r = hashmap_put(m->user_units, u->service, u);
  97         if (r < 0)
  98                 return r;
  99
 100         *out = u;
 101         u = NULL;
 102         return 0;
 103 }
 104
 105 User *user_free(User *u) {
 106         if (!u)
 107                 return NULL;
 108
 109         if (u->in_gc_queue)
 110                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
 111
 112         while (u->sessions)
 113                 session_free(u->sessions);
 114
 115         if (u->service)
 116                 hashmap_remove_value(u->manager->user_units, u->service, u);
 117
 118         if (u->slice)
 119                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 120
 121         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 122
 123         u->slice_job = mfree(u->slice_job);
 124         u->service_job = mfree(u->service_job);
 125
 126         u->service = mfree(u->service);
 127         u->slice = mfree(u->slice);
 128         u->runtime_path = mfree(u->runtime_path);
 129         u->state_file = mfree(u->state_file);
 130         u->name = mfree(u->name);
 131
 132         return mfree(u);
 133 }
 134
 135 static int user_save_internal(User *u) {
 136         _cleanup_free_ char *temp_path = NULL;
 137         _cleanup_fclose_ FILE *f = NULL;
 138         int r;
 139
 140         assert(u);
 141         assert(u->state_file);
 142
 143         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0);
 144         if (r < 0)
 145                 goto fail;
 146
 147         r = fopen_temporary(u->state_file, &f, &temp_path);
 148         if (r < 0)
 149                 goto fail;
 150
 151         fchmod(fileno(f), 0644);
 152
 153         fprintf(f,
 154                 "# This is private data. Do not parse.\n"
 155                 "NAME=%s\n"
 156                 "STATE=%s\n",
 157                 u->name,
 158                 user_state_to_string(user_get_state(u)));
 159
 160         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 161         if (u->runtime_path)
 162                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 163
 164         if (u->service_job)
 165                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 166
 167         if (u->slice_job)
 168                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 169
 170         if (u->display)
 171                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 172
 173         if (dual_timestamp_is_set(&u->timestamp))
 174                 fprintf(f,
 175                         "REALTIME="USEC_FMT"\n"
 176                         "MONOTONIC="USEC_FMT"\n",
 177                         u->timestamp.realtime,
 178                         u->timestamp.monotonic);
 179
 180         if (u->sessions) {
 181                 Session *i;
 182                 bool first;
 183
 184                 fputs("SESSIONS=", f);
 185                 first = true;
 186                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 187                         if (first)
 188                                 first = false;
 189                         else
 190                                 fputc(' ', f);
 191
 192                         fputs(i->id, f);
 193                 }
 194
 195                 fputs("\nSEATS=", f);
 196                 first = true;
 197                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 198                         if (!i->seat)
 199                                 continue;
 200
 201                         if (first)
 202                                 first = false;
 203                         else
 204                                 fputc(' ', f);
 205
 206                         fputs(i->seat->id, f);
 207                 }
 208
 209                 fputs("\nACTIVE_SESSIONS=", f);
 210                 first = true;
 211                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 212                         if (!session_is_active(i))
 213                                 continue;
 214
 215                         if (first)
 216                                 first = false;
 217                         else
 218                                 fputc(' ', f);
 219
 220                         fputs(i->id, f);
 221                 }
 222
 223                 fputs("\nONLINE_SESSIONS=", f);
 224                 first = true;
 225                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 226                         if (session_get_state(i) == SESSION_CLOSING)
 227                                 continue;
 228
 229                         if (first)
 230                                 first = false;
 231                         else
 232                                 fputc(' ', f);
 233
 234                         fputs(i->id, f);
 235                 }
 236
 237                 fputs("\nACTIVE_SEATS=", f);
 238                 first = true;
 239                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 240                         if (!session_is_active(i) || !i->seat)
 241                                 continue;
 242
 243                         if (first)
 244                                 first = false;
 245                         else
 246                                 fputc(' ', f);
 247
 248                         fputs(i->seat->id, f);
 249                 }
 250
 251                 fputs("\nONLINE_SEATS=", f);
 252                 first = true;
 253                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 254                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 255                                 continue;
 256
 257                         if (first)
 258                                 first = false;
 259                         else
 260                                 fputc(' ', f);
 261
 262                         fputs(i->seat->id, f);
 263                 }
 264                 fputc('\n', f);
 265         }
 266
 267         r = fflush_and_check(f);
 268         if (r < 0)
 269                 goto fail;
 270
 271         if (rename(temp_path, u->state_file) < 0) {
 272                 r = -errno;
 273                 goto fail;
 274         }
 275
 276         return 0;
 277
 278 fail:
 279         (void) unlink(u->state_file);
 280
 281         if (temp_path)
 282                 (void) unlink(temp_path);
 283
 284         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 285 }
 286
 287 int user_save(User *u) {
 288         assert(u);
 289
 290         if (!u->started)
 291                 return 0;
 292
 293         return user_save_internal (u);
 294 }
 295
 296 int user_load(User *u) {
 297         _cleanup_free_ char *display = NULL, *realtime = NULL, *monotonic = NULL;
 298         Session *s = NULL;
 299         int r;
 300
 301         assert(u);
 302
 303         r = parse_env_file(u->state_file, NEWLINE,
 304                            "SERVICE_JOB", &u->service_job,
 305                            "SLICE_JOB",   &u->slice_job,
 306                            "DISPLAY",     &display,
 307                            "REALTIME",    &realtime,
 308                            "MONOTONIC",   &monotonic,
 309                            NULL);
 310         if (r < 0) {
 311                 if (r == -ENOENT)
 312                         return 0;
 313
 314                 log_error_errno(r, "Failed to read %s: %m", u->state_file);
 315                 return r;
 316         }
 317
 318         if (display)
 319                 s = hashmap_get(u->manager->sessions, display);
 320
 321         if (s && s->display && display_is_local(s->display))
 322                 u->display = s;
 323
 324         if (realtime) {
 325                 unsigned long long l;
 326                 if (sscanf(realtime, "%llu", &l) > 0)
 327                         u->timestamp.realtime = l;
 328         }
 329
 330         if (monotonic) {
 331                 unsigned long long l;
 332                 if (sscanf(monotonic, "%llu", &l) > 0)
 333                         u->timestamp.monotonic = l;
 334         }
 335
 336         return r;
 337 }
 338
 339 static int user_mkdir_runtime_path(User *u) {
 340         int r;
 341
 342         assert(u);
 343
 344         r = mkdir_safe_label("/run/user", 0755, 0, 0);
 345         if (r < 0)
 346                 return log_error_errno(r, "Failed to create /run/user: %m");
 347
 348         if (path_is_mount_point(u->runtime_path, 0) <= 0) {
 349                 _cleanup_free_ char *t = NULL;
 350
 351                 (void) mkdir_label(u->runtime_path, 0700);
 352
 353                 if (mac_smack_use())
 354                         r = asprintf(&t, "mode=0700,smackfsroot=*,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu", u->uid, u->gid, u->manager->runtime_dir_size);
 355                 else
 356                         r = asprintf(&t, "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu", u->uid, u->gid, u->manager->runtime_dir_size);
 357                 if (r < 0) {
 358                         r = log_oom();
 359                         goto fail;
 360                 }
 361
 362                 r = mount("tmpfs", u->runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, t);
 363                 if (r < 0) {
 364                         if (errno != EPERM) {
 365                                 r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", u->runtime_path);
 366                                 goto fail;
 367                         }
 368
 369                         /* Lacking permissions, maybe
 370                          * CAP_SYS_ADMIN-less container? In this case,
 371                          * just use a normal directory. */
 372
 373                         r = chmod_and_chown(u->runtime_path, 0700, u->uid, u->gid);
 374                         if (r < 0) {
 375                                 log_error_errno(r, "Failed to change runtime directory ownership and mode: %m");
 376                                 goto fail;
 377                         }
 378                 }
 379
 380                 r = label_fix(u->runtime_path, false, false);
 381                 if (r < 0)
 382                         log_warning_errno(r, "Failed to fix label of '%s', ignoring: %m", u->runtime_path);
 383         }
 384
 385         return 0;
 386
 387 fail:
 388         /* Try to clean up, but ignore errors */
 389         (void) rmdir(u->runtime_path);
 390         return r;
 391 }
 392
 393 static int user_start_slice(User *u) {
 394         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 395         const char *description;
 396         char *job;
 397         int r;
 398
 399         assert(u);
 400
 401         u->slice_job = mfree(u->slice_job);
 402         description = strjoina("User Slice of ", u->name);
 403
 404         r = manager_start_slice(
 405                         u->manager,
 406                         u->slice,
 407                         description,
 408                         "systemd-logind.service",
 409                         "systemd-user-sessions.service",
 410                         u->manager->user_tasks_max,
 411                         &error,
 412                         &job);
 413         if (r >= 0)
 414                 u->slice_job = job;
 415         else if (!sd_bus_error_has_name(&error, BUS_ERROR_UNIT_EXISTS))
 416                 /* we don't fail due to this, let's try to continue */
 417                 log_error_errno(r, "Failed to start user slice %s, ignoring: %s (%s)",
 418                                 u->slice, bus_error_message(&error, r), error.name);
 419
 420         return 0;
 421 }
 422
 423 static int user_start_service(User *u) {
 424         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 425         char *job;
 426         int r;
 427
 428         assert(u);
 429
 430         u->service_job = mfree(u->service_job);
 431
 432         r = manager_start_unit(
 433                         u->manager,
 434                         u->service,
 435                         &error,
 436                         &job);
 437         if (r < 0) {
 438                 /* we don't fail due to this, let's try to continue */
 439                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 440         } else {
 441                 u->service_job = job;
 442         }
 443
 444         return 0;
 445 }
 446
 447 int user_start(User *u) {
 448         int r;
 449
 450         assert(u);
 451
 452         if (u->started && !u->stopping)
 453                 return 0;
 454
 455         /*
 456          * If u->stopping is set, the user is marked for removal and the slice
 457          * and service stop-jobs are queued. We have to clear that flag before
 458          * queing the start-jobs again. If they succeed, the user object can be
 459          * re-used just fine (pid1 takes care of job-ordering and proper
 460          * restart), but if they fail, we want to force another user_stop() so
 461          * possibly pending units are stopped.
 462          * Note that we don't clear u->started, as we have no clue what state
 463          * the user is in on failure here. Hence, we pretend the user is
 464          * running so it will be properly taken down by GC. However, we clearly
 465          * return an error from user_start() in that case, so no further
 466          * reference to the user is taken.
 467          */
 468         u->stopping = false;
 469
 470         if (!u->started) {
 471                 log_debug("New user %s logged in.", u->name);
 472
 473                 /* Make XDG_RUNTIME_DIR */
 474                 r = user_mkdir_runtime_path(u);
 475                 if (r < 0)
 476                         return r;
 477         }
 478
 479         /* Create cgroup */
 480         r = user_start_slice(u);
 481         if (r < 0)
 482                 return r;
 483
 484         /* Save the user data so far, because pam_systemd will read the
 485          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 486          * We need to do user_save_internal() because we have not
 487          * "officially" started yet. */
 488         user_save_internal(u);
 489
 490         /* Spawn user systemd */
 491         r = user_start_service(u);
 492         if (r < 0)
 493                 return r;
 494
 495         if (!u->started) {
 496                 if (!dual_timestamp_is_set(&u->timestamp))
 497                         dual_timestamp_get(&u->timestamp);
 498                 user_send_signal(u, true);
 499                 u->started = true;
 500         }
 501
 502         /* Save new user data */
 503         user_save(u);
 504
 505         return 0;
 506 }
 507
 508 static int user_stop_slice(User *u) {
 509         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 510         char *job;
 511         int r;
 512
 513         assert(u);
 514
 515         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 516         if (r < 0) {
 517                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 518                 return r;
 519         }
 520
 521         free(u->slice_job);
 522         u->slice_job = job;
 523
 524         return r;
 525 }
 526
 527 static int user_stop_service(User *u) {
 528         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 529         char *job;
 530         int r;
 531
 532         assert(u);
 533
 534         r = manager_stop_unit(u->manager, u->service, &error, &job);
 535         if (r < 0) {
 536                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 537                 return r;
 538         }
 539
 540         free(u->service_job);
 541         u->service_job = job;
 542
 543         return r;
 544 }
 545
 546 static int user_remove_runtime_path(User *u) {
 547         int r;
 548
 549         assert(u);
 550
 551         r = rm_rf(u->runtime_path, 0);
 552         if (r < 0)
 553                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
 554
 555         /* Ignore cases where the directory isn't mounted, as that's
 556          * quite possible, if we lacked the permissions to mount
 557          * something */
 558         r = umount2(u->runtime_path, MNT_DETACH);
 559         if (r < 0 && errno != EINVAL && errno != ENOENT)
 560                 log_error_errno(errno, "Failed to unmount user runtime directory %s: %m", u->runtime_path);
 561
 562         r = rm_rf(u->runtime_path, REMOVE_ROOT);
 563         if (r < 0)
 564                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
 565
 566         return r;
 567 }
 568
 569 int user_stop(User *u, bool force) {
 570         Session *s;
 571         int r = 0, k;
 572         assert(u);
 573
 574         /* Stop jobs have already been queued */
 575         if (u->stopping) {
 576                 user_save(u);
 577                 return r;
 578         }
 579
 580         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 581                 k = session_stop(s, force);
 582                 if (k < 0)
 583                         r = k;
 584         }
 585
 586         /* Kill systemd */
 587         k = user_stop_service(u);
 588         if (k < 0)
 589                 r = k;
 590
 591         /* Kill cgroup */
 592         k = user_stop_slice(u);
 593         if (k < 0)
 594                 r = k;
 595
 596         u->stopping = true;
 597
 598         user_save(u);
 599
 600         return r;
 601 }
 602
 603 int user_finalize(User *u) {
 604         Session *s;
 605         int r = 0, k;
 606
 607         assert(u);
 608
 609         if (u->started)
 610                 log_debug("User %s logged out.", u->name);
 611
 612         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 613                 k = session_finalize(s);
 614                 if (k < 0)
 615                         r = k;
 616         }
 617
 618         /* Kill XDG_RUNTIME_DIR */
 619         k = user_remove_runtime_path(u);
 620         if (k < 0)
 621                 r = k;
 622
 623         /* Clean SysV + POSIX IPC objects */
 624         if (u->manager->remove_ipc) {
 625                 k = clean_ipc(u->uid);
 626                 if (k < 0)
 627                         r = k;
 628         }
 629
 630         unlink(u->state_file);
 631         user_add_to_gc_queue(u);
 632
 633         if (u->started) {
 634                 user_send_signal(u, false);
 635                 u->started = false;
 636         }
 637
 638         return r;
 639 }
 640
 641 int user_get_idle_hint(User *u, dual_timestamp *t) {
 642         Session *s;
 643         bool idle_hint = true;
 644         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 645
 646         assert(u);
 647
 648         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 649                 dual_timestamp k;
 650                 int ih;
 651
 652                 ih = session_get_idle_hint(s, &k);
 653                 if (ih < 0)
 654                         return ih;
 655
 656                 if (!ih) {
 657                         if (!idle_hint) {
 658                                 if (k.monotonic < ts.monotonic)
 659                                         ts = k;
 660                         } else {
 661                                 idle_hint = false;
 662                                 ts = k;
 663                         }
 664                 } else if (idle_hint) {
 665
 666                         if (k.monotonic > ts.monotonic)
 667                                 ts = k;
 668                 }
 669         }
 670
 671         if (t)
 672                 *t = ts;
 673
 674         return idle_hint;
 675 }
 676
 677 int user_check_linger_file(User *u) {
 678         _cleanup_free_ char *cc = NULL;
 679         char *p = NULL;
 680
 681         cc = cescape(u->name);
 682         if (!cc)
 683                 return -ENOMEM;
 684
 685         p = strjoina("/var/lib/systemd/linger/", cc);
 686
 687         return access(p, F_OK) >= 0;
 688 }
 689
 690 bool user_check_gc(User *u, bool drop_not_started) {
 691         assert(u);
 692
 693         if (drop_not_started && !u->started)
 694                 return false;
 695
 696         if (u->sessions)
 697                 return true;
 698
 699         if (user_check_linger_file(u) > 0)
 700                 return true;
 701
 702         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 703                 return true;
 704
 705         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 706                 return true;
 707
 708         return false;
 709 }
 710
 711 void user_add_to_gc_queue(User *u) {
 712         assert(u);
 713
 714         if (u->in_gc_queue)
 715                 return;
 716
 717         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 718         u->in_gc_queue = true;
 719 }
 720
 721 UserState user_get_state(User *u) {
 722         Session *i;
 723
 724         assert(u);
 725
 726         if (u->stopping)
 727                 return USER_CLOSING;
 728
 729         if (!u->started || u->slice_job || u->service_job)
 730                 return USER_OPENING;
 731
 732         if (u->sessions) {
 733                 bool all_closing = true;
 734
 735                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 736                         SessionState state;
 737
 738                         state = session_get_state(i);
 739                         if (state == SESSION_ACTIVE)
 740                                 return USER_ACTIVE;
 741                         if (state != SESSION_CLOSING)
 742                                 all_closing = false;
 743                 }
 744
 745                 return all_closing ? USER_CLOSING : USER_ONLINE;
 746         }
 747
 748         if (user_check_linger_file(u) > 0)
 749                 return USER_LINGERING;
 750
 751         return USER_CLOSING;
 752 }
 753
 754 int user_kill(User *u, int signo) {
 755         assert(u);
 756
 757         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 758 }
 759
 760 static bool elect_display_filter(Session *s) {
 761         /* Return true if the session is a candidate for the user’s ‘primary
 762          * session’ or ‘display’. */
 763         assert(s);
 764
 765         return (s->class == SESSION_USER && !s->stopping);
 766 }
 767
 768 static int elect_display_compare(Session *s1, Session *s2) {
 769         /* Indexed by SessionType. Lower numbers mean more preferred. */
 770         const int type_ranks[_SESSION_TYPE_MAX] = {
 771                 [SESSION_UNSPECIFIED] = 0,
 772                 [SESSION_TTY] = -2,
 773                 [SESSION_X11] = -3,
 774                 [SESSION_WAYLAND] = -3,
 775                 [SESSION_MIR] = -3,
 776                 [SESSION_WEB] = -1,
 777         };
 778
 779         /* Calculate the partial order relationship between s1 and s2,
 780          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 781          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 782          * is preferred.
 783          *
 784          * s1 or s2 may be NULL. */
 785         if (!s1 && !s2)
 786                 return 0;
 787
 788         if ((s1 == NULL) != (s2 == NULL))
 789                 return (s1 == NULL) - (s2 == NULL);
 790
 791         if (s1->stopping != s2->stopping)
 792                 return s1->stopping - s2->stopping;
 793
 794         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 795                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 796
 797         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 798                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 799
 800         if (s1->type != s2->type)
 801                 return type_ranks[s1->type] - type_ranks[s2->type];
 802
 803         return 0;
 804 }
 805
 806 void user_elect_display(User *u) {
 807         Session *s;
 808
 809         assert(u);
 810
 811         /* This elects a primary session for each user, which we call
 812          * the "display". We try to keep the assignment stable, but we
 813          * "upgrade" to better choices. */
 814         log_debug("Electing new display for user %s", u->name);
 815
 816         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 817                 if (!elect_display_filter(s)) {
 818                         log_debug("Ignoring session %s", s->id);
 819                         continue;
 820                 }
 821
 822                 if (elect_display_compare(s, u->display) < 0) {
 823                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 824                         u->display = s;
 825                 }
 826         }
 827 }
 828
 829 static const char* const user_state_table[_USER_STATE_MAX] = {
 830         [USER_OFFLINE] = "offline",
 831         [USER_OPENING] = "opening",
 832         [USER_LINGERING] = "lingering",
 833         [USER_ONLINE] = "online",
 834         [USER_ACTIVE] = "active",
 835         [USER_CLOSING] = "closing"
 836 };
 837
 838 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 839
 840 int config_parse_tmpfs_size(
 841                 const char* unit,
 842                 const char *filename,
 843                 unsigned line,
 844                 const char *section,
 845                 unsigned section_line,
 846                 const char *lvalue,
 847                 int ltype,
 848                 const char *rvalue,
 849                 void *data,
 850                 void *userdata) {
 851
 852         size_t *sz = data;
 853         const char *e;
 854         int r;
 855
 856         assert(filename);
 857         assert(lvalue);
 858         assert(rvalue);
 859         assert(data);
 860
 861         e = endswith(rvalue, "%");
 862         if (e) {
 863                 unsigned long ul;
 864                 char *f;
 865
 866                 errno = 0;
 867                 ul = strtoul(rvalue, &f, 10);
 868                 if (errno > 0 || f != e) {
 869                         log_syntax(unit, LOG_ERR, filename, line, errno, "Failed to parse percentage value, ignoring: %s", rvalue);
 870                         return 0;
 871                 }
 872
 873                 if (ul <= 0 || ul >= 100) {
 874                         log_syntax(unit, LOG_ERR, filename, line, 0, "Percentage value out of range, ignoring: %s", rvalue);
 875                         return 0;
 876                 }
 877
 878                 *sz = PAGE_ALIGN((size_t) ((physical_memory() * (uint64_t) ul) / (uint64_t) 100));
 879         } else {
 880                 uint64_t k;
 881
 882                 r = parse_size(rvalue, 1024, &k);
 883                 if (r < 0 || (uint64_t) (size_t) k != k) {
 884                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value, ignoring: %s", rvalue);
 885                         return 0;
 886                 }
 887
 888                 *sz = PAGE_ALIGN((size_t) k);
 889         }
 890
 891         return 0;
 892 }