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 "cgroup-util.h"
  30 #include "clean-ipc.h"
  31 #include "conf-parser.h"
  32 #include "escape.h"
  33 #include "fd-util.h"
  34 #include "fileio.h"
  35 #include "formats-util.h"
  36 #include "fs-util.h"
  37 #include "hashmap.h"
  38 #include "label.h"
  39 #include "logind-user.h"
  40 #include "mkdir.h"
  41 #include "mount-util.h"
  42 #include "parse-util.h"
  43 #include "path-util.h"
  44 #include "rm-rf.h"
  45 #include "smack-util.h"
  46 #include "special.h"
  47 #include "stdio-util.h"
  48 #include "string-table.h"
  49 #include "unit-name.h"
  50 #include "user-util.h"
  51 #include "util.h"
  52
  53 int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
  54         _cleanup_(user_freep) User *u = NULL;
  55         char lu[DECIMAL_STR_MAX(uid_t) + 1];
  56         int r;
  57
  58         assert(out);
  59         assert(m);
  60         assert(name);
  61
  62         u = new0(User, 1);
  63         if (!u)
  64                 return -ENOMEM;
  65
  66         u->manager = m;
  67         u->uid = uid;
  68         u->gid = gid;
  69         xsprintf(lu, UID_FMT, uid);
  70
  71         u->name = strdup(name);
  72         if (!u->name)
  73                 return -ENOMEM;
  74
  75         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  76                 return -ENOMEM;
  77
  78         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  79                 return -ENOMEM;
  80
  81         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  82         if (r < 0)
  83                 return r;
  84
  85         r = unit_name_build("user", lu, ".service", &u->service);
  86         if (r < 0)
  87                 return r;
  88
  89         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  90         if (r < 0)
  91                 return r;
  92
  93         r = hashmap_put(m->user_units, u->slice, u);
  94         if (r < 0)
  95                 return r;
  96
  97         r = hashmap_put(m->user_units, u->service, u);
  98         if (r < 0)
  99                 return r;
 100
 101         *out = u;
 102         u = NULL;
 103         return 0;
 104 }
 105
 106 User *user_free(User *u) {
 107         if (!u)
 108                 return NULL;
 109
 110         if (u->in_gc_queue)
 111                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
 112
 113         while (u->sessions)
 114                 session_free(u->sessions);
 115
 116         if (u->service)
 117                 hashmap_remove_value(u->manager->user_units, u->service, u);
 118
 119         if (u->slice)
 120                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 121
 122         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 123
 124         u->slice_job = mfree(u->slice_job);
 125         u->service_job = mfree(u->service_job);
 126
 127         u->service = mfree(u->service);
 128         u->slice = mfree(u->slice);
 129         u->runtime_path = mfree(u->runtime_path);
 130         u->state_file = mfree(u->state_file);
 131         u->name = mfree(u->name);
 132
 133         return mfree(u);
 134 }
 135
 136 static int user_save_internal(User *u) {
 137         _cleanup_free_ char *temp_path = NULL;
 138         _cleanup_fclose_ FILE *f = NULL;
 139         int r;
 140
 141         assert(u);
 142         assert(u->state_file);
 143
 144         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0);
 145         if (r < 0)
 146                 goto fail;
 147
 148         r = fopen_temporary(u->state_file, &f, &temp_path);
 149         if (r < 0)
 150                 goto fail;
 151
 152         fchmod(fileno(f), 0644);
 153
 154         fprintf(f,
 155                 "# This is private data. Do not parse.\n"
 156                 "NAME=%s\n"
 157                 "STATE=%s\n",
 158                 u->name,
 159                 user_state_to_string(user_get_state(u)));
 160
 161         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 162         if (u->runtime_path)
 163                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 164
 165         if (u->service_job)
 166                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 167
 168         if (u->slice_job)
 169                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 170
 171         if (u->display)
 172                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 173
 174         if (dual_timestamp_is_set(&u->timestamp))
 175                 fprintf(f,
 176                         "REALTIME="USEC_FMT"\n"
 177                         "MONOTONIC="USEC_FMT"\n",
 178                         u->timestamp.realtime,
 179                         u->timestamp.monotonic);
 180
 181         if (u->sessions) {
 182                 Session *i;
 183                 bool first;
 184
 185                 fputs("SESSIONS=", f);
 186                 first = true;
 187                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 188                         if (first)
 189                                 first = false;
 190                         else
 191                                 fputc(' ', f);
 192
 193                         fputs(i->id, f);
 194                 }
 195
 196                 fputs("\nSEATS=", f);
 197                 first = true;
 198                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 199                         if (!i->seat)
 200                                 continue;
 201
 202                         if (first)
 203                                 first = false;
 204                         else
 205                                 fputc(' ', f);
 206
 207                         fputs(i->seat->id, f);
 208                 }
 209
 210                 fputs("\nACTIVE_SESSIONS=", f);
 211                 first = true;
 212                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 213                         if (!session_is_active(i))
 214                                 continue;
 215
 216                         if (first)
 217                                 first = false;
 218                         else
 219                                 fputc(' ', f);
 220
 221                         fputs(i->id, f);
 222                 }
 223
 224                 fputs("\nONLINE_SESSIONS=", f);
 225                 first = true;
 226                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 227                         if (session_get_state(i) == SESSION_CLOSING)
 228                                 continue;
 229
 230                         if (first)
 231                                 first = false;
 232                         else
 233                                 fputc(' ', f);
 234
 235                         fputs(i->id, f);
 236                 }
 237
 238                 fputs("\nACTIVE_SEATS=", f);
 239                 first = true;
 240                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 241                         if (!session_is_active(i) || !i->seat)
 242                                 continue;
 243
 244                         if (first)
 245                                 first = false;
 246                         else
 247                                 fputc(' ', f);
 248
 249                         fputs(i->seat->id, f);
 250                 }
 251
 252                 fputs("\nONLINE_SEATS=", f);
 253                 first = true;
 254                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 255                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 256                                 continue;
 257
 258                         if (first)
 259                                 first = false;
 260                         else
 261                                 fputc(' ', f);
 262
 263                         fputs(i->seat->id, f);
 264                 }
 265                 fputc('\n', f);
 266         }
 267
 268         r = fflush_and_check(f);
 269         if (r < 0)
 270                 goto fail;
 271
 272         if (rename(temp_path, u->state_file) < 0) {
 273                 r = -errno;
 274                 goto fail;
 275         }
 276
 277         return 0;
 278
 279 fail:
 280         (void) unlink(u->state_file);
 281
 282         if (temp_path)
 283                 (void) unlink(temp_path);
 284
 285         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 286 }
 287
 288 int user_save(User *u) {
 289         assert(u);
 290
 291         if (!u->started)
 292                 return 0;
 293
 294         return user_save_internal (u);
 295 }
 296
 297 int user_load(User *u) {
 298         _cleanup_free_ char *display = NULL, *realtime = NULL, *monotonic = NULL;
 299         Session *s = NULL;
 300         int r;
 301
 302         assert(u);
 303
 304         r = parse_env_file(u->state_file, NEWLINE,
 305                            "SERVICE_JOB", &u->service_job,
 306                            "SLICE_JOB",   &u->slice_job,
 307                            "DISPLAY",     &display,
 308                            "REALTIME",    &realtime,
 309                            "MONOTONIC",   &monotonic,
 310                            NULL);
 311         if (r < 0) {
 312                 if (r == -ENOENT)
 313                         return 0;
 314
 315                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 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                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 326         if (monotonic)
 327                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 328
 329         return r;
 330 }
 331
 332 static int user_mkdir_runtime_path(User *u) {
 333         int r;
 334
 335         assert(u);
 336
 337         r = mkdir_safe_label("/run/user", 0755, 0, 0);
 338         if (r < 0)
 339                 return log_error_errno(r, "Failed to create /run/user: %m");
 340
 341         if (path_is_mount_point(u->runtime_path, 0) <= 0) {
 342                 _cleanup_free_ char *t = NULL;
 343
 344                 (void) mkdir_label(u->runtime_path, 0700);
 345
 346                 if (mac_smack_use())
 347                         r = asprintf(&t, "mode=0700,smackfsroot=*,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu", u->uid, u->gid, u->manager->runtime_dir_size);
 348                 else
 349                         r = asprintf(&t, "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu", u->uid, u->gid, u->manager->runtime_dir_size);
 350                 if (r < 0) {
 351                         r = log_oom();
 352                         goto fail;
 353                 }
 354
 355                 r = mount("tmpfs", u->runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, t);
 356                 if (r < 0) {
 357                         if (errno != EPERM) {
 358                                 r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", u->runtime_path);
 359                                 goto fail;
 360                         }
 361
 362                         /* Lacking permissions, maybe
 363                          * CAP_SYS_ADMIN-less container? In this case,
 364                          * just use a normal directory. */
 365
 366                         r = chmod_and_chown(u->runtime_path, 0700, u->uid, u->gid);
 367                         if (r < 0) {
 368                                 log_error_errno(r, "Failed to change runtime directory ownership and mode: %m");
 369                                 goto fail;
 370                         }
 371                 }
 372
 373                 r = label_fix(u->runtime_path, false, false);
 374                 if (r < 0)
 375                         log_warning_errno(r, "Failed to fix label of '%s', ignoring: %m", u->runtime_path);
 376         }
 377
 378         return 0;
 379
 380 fail:
 381         /* Try to clean up, but ignore errors */
 382         (void) rmdir(u->runtime_path);
 383         return r;
 384 }
 385
 386 static int user_start_slice(User *u) {
 387         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 388         const char *description;
 389         char *job;
 390         int r;
 391
 392         assert(u);
 393
 394         u->slice_job = mfree(u->slice_job);
 395         description = strjoina("User Slice of ", u->name);
 396
 397         r = manager_start_slice(
 398                         u->manager,
 399                         u->slice,
 400                         description,
 401                         "systemd-logind.service",
 402                         "systemd-user-sessions.service",
 403                         u->manager->user_tasks_max,
 404                         &error,
 405                         &job);
 406         if (r >= 0)
 407                 u->slice_job = job;
 408         else if (!sd_bus_error_has_name(&error, BUS_ERROR_UNIT_EXISTS))
 409                 /* we don't fail due to this, let's try to continue */
 410                 log_error_errno(r, "Failed to start user slice %s, ignoring: %s (%s)",
 411                                 u->slice, bus_error_message(&error, r), error.name);
 412
 413         return 0;
 414 }
 415
 416 static int user_start_service(User *u) {
 417         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 418         char *job;
 419         int r;
 420
 421         assert(u);
 422
 423         u->service_job = mfree(u->service_job);
 424
 425         r = manager_start_unit(
 426                         u->manager,
 427                         u->service,
 428                         &error,
 429                         &job);
 430         if (r < 0) {
 431                 /* we don't fail due to this, let's try to continue */
 432                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 433         } else {
 434                 u->service_job = job;
 435         }
 436
 437         return 0;
 438 }
 439
 440 int user_start(User *u) {
 441         int r;
 442
 443         assert(u);
 444
 445         if (u->started && !u->stopping)
 446                 return 0;
 447
 448         /*
 449          * If u->stopping is set, the user is marked for removal and the slice
 450          * and service stop-jobs are queued. We have to clear that flag before
 451          * queing the start-jobs again. If they succeed, the user object can be
 452          * re-used just fine (pid1 takes care of job-ordering and proper
 453          * restart), but if they fail, we want to force another user_stop() so
 454          * possibly pending units are stopped.
 455          * Note that we don't clear u->started, as we have no clue what state
 456          * the user is in on failure here. Hence, we pretend the user is
 457          * running so it will be properly taken down by GC. However, we clearly
 458          * return an error from user_start() in that case, so no further
 459          * reference to the user is taken.
 460          */
 461         u->stopping = false;
 462
 463         if (!u->started) {
 464                 log_debug("New user %s logged in.", u->name);
 465
 466                 /* Make XDG_RUNTIME_DIR */
 467                 r = user_mkdir_runtime_path(u);
 468                 if (r < 0)
 469                         return r;
 470         }
 471
 472         /* Create cgroup */
 473         r = user_start_slice(u);
 474         if (r < 0)
 475                 return r;
 476
 477         /* Save the user data so far, because pam_systemd will read the
 478          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 479          * We need to do user_save_internal() because we have not
 480          * "officially" started yet. */
 481         user_save_internal(u);
 482
 483         /* Spawn user systemd */
 484         r = user_start_service(u);
 485         if (r < 0)
 486                 return r;
 487
 488         if (!u->started) {
 489                 if (!dual_timestamp_is_set(&u->timestamp))
 490                         dual_timestamp_get(&u->timestamp);
 491                 user_send_signal(u, true);
 492                 u->started = true;
 493         }
 494
 495         /* Save new user data */
 496         user_save(u);
 497
 498         return 0;
 499 }
 500
 501 static int user_stop_slice(User *u) {
 502         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 503         char *job;
 504         int r;
 505
 506         assert(u);
 507
 508         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 509         if (r < 0) {
 510                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 511                 return r;
 512         }
 513
 514         free(u->slice_job);
 515         u->slice_job = job;
 516
 517         return r;
 518 }
 519
 520 static int user_stop_service(User *u) {
 521         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 522         char *job;
 523         int r;
 524
 525         assert(u);
 526
 527         r = manager_stop_unit(u->manager, u->service, &error, &job);
 528         if (r < 0) {
 529                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 530                 return r;
 531         }
 532
 533         free(u->service_job);
 534         u->service_job = job;
 535
 536         return r;
 537 }
 538
 539 static int user_remove_runtime_path(User *u) {
 540         int r;
 541
 542         assert(u);
 543
 544         r = rm_rf(u->runtime_path, 0);
 545         if (r < 0)
 546                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
 547
 548         /* Ignore cases where the directory isn't mounted, as that's
 549          * quite possible, if we lacked the permissions to mount
 550          * something */
 551         r = umount2(u->runtime_path, MNT_DETACH);
 552         if (r < 0 && errno != EINVAL && errno != ENOENT)
 553                 log_error_errno(errno, "Failed to unmount user runtime directory %s: %m", u->runtime_path);
 554
 555         r = rm_rf(u->runtime_path, REMOVE_ROOT);
 556         if (r < 0)
 557                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
 558
 559         return r;
 560 }
 561
 562 int user_stop(User *u, bool force) {
 563         Session *s;
 564         int r = 0, k;
 565         assert(u);
 566
 567         /* Stop jobs have already been queued */
 568         if (u->stopping) {
 569                 user_save(u);
 570                 return r;
 571         }
 572
 573         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 574                 k = session_stop(s, force);
 575                 if (k < 0)
 576                         r = k;
 577         }
 578
 579         /* Kill systemd */
 580         k = user_stop_service(u);
 581         if (k < 0)
 582                 r = k;
 583
 584         /* Kill cgroup */
 585         k = user_stop_slice(u);
 586         if (k < 0)
 587                 r = k;
 588
 589         u->stopping = true;
 590
 591         user_save(u);
 592
 593         return r;
 594 }
 595
 596 int user_finalize(User *u) {
 597         Session *s;
 598         int r = 0, k;
 599
 600         assert(u);
 601
 602         if (u->started)
 603                 log_debug("User %s logged out.", u->name);
 604
 605         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 606                 k = session_finalize(s);
 607                 if (k < 0)
 608                         r = k;
 609         }
 610
 611         /* Kill XDG_RUNTIME_DIR */
 612         k = user_remove_runtime_path(u);
 613         if (k < 0)
 614                 r = k;
 615
 616         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 617          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 618          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 619          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 620          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 621          * and do it only for normal users. */
 622         if (u->manager->remove_ipc && u->uid > SYSTEM_UID_MAX) {
 623                 k = clean_ipc_by_uid(u->uid);
 624                 if (k < 0)
 625                         r = k;
 626         }
 627
 628         unlink(u->state_file);
 629         user_add_to_gc_queue(u);
 630
 631         if (u->started) {
 632                 user_send_signal(u, false);
 633                 u->started = false;
 634         }
 635
 636         return r;
 637 }
 638
 639 int user_get_idle_hint(User *u, dual_timestamp *t) {
 640         Session *s;
 641         bool idle_hint = true;
 642         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 643
 644         assert(u);
 645
 646         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 647                 dual_timestamp k;
 648                 int ih;
 649
 650                 ih = session_get_idle_hint(s, &k);
 651                 if (ih < 0)
 652                         return ih;
 653
 654                 if (!ih) {
 655                         if (!idle_hint) {
 656                                 if (k.monotonic < ts.monotonic)
 657                                         ts = k;
 658                         } else {
 659                                 idle_hint = false;
 660                                 ts = k;
 661                         }
 662                 } else if (idle_hint) {
 663
 664                         if (k.monotonic > ts.monotonic)
 665                                 ts = k;
 666                 }
 667         }
 668
 669         if (t)
 670                 *t = ts;
 671
 672         return idle_hint;
 673 }
 674
 675 int user_check_linger_file(User *u) {
 676         _cleanup_free_ char *cc = NULL;
 677         char *p = NULL;
 678
 679         cc = cescape(u->name);
 680         if (!cc)
 681                 return -ENOMEM;
 682
 683         p = strjoina("/var/lib/systemd/linger/", cc);
 684
 685         return access(p, F_OK) >= 0;
 686 }
 687
 688 bool user_check_gc(User *u, bool drop_not_started) {
 689         assert(u);
 690
 691         if (drop_not_started && !u->started)
 692                 return false;
 693
 694         if (u->sessions)
 695                 return true;
 696
 697         if (user_check_linger_file(u) > 0)
 698                 return true;
 699
 700         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 701                 return true;
 702
 703         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 704                 return true;
 705
 706         return false;
 707 }
 708
 709 void user_add_to_gc_queue(User *u) {
 710         assert(u);
 711
 712         if (u->in_gc_queue)
 713                 return;
 714
 715         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 716         u->in_gc_queue = true;
 717 }
 718
 719 UserState user_get_state(User *u) {
 720         Session *i;
 721
 722         assert(u);
 723
 724         if (u->stopping)
 725                 return USER_CLOSING;
 726
 727         if (!u->started || u->slice_job || u->service_job)
 728                 return USER_OPENING;
 729
 730         if (u->sessions) {
 731                 bool all_closing = true;
 732
 733                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 734                         SessionState state;
 735
 736                         state = session_get_state(i);
 737                         if (state == SESSION_ACTIVE)
 738                                 return USER_ACTIVE;
 739                         if (state != SESSION_CLOSING)
 740                                 all_closing = false;
 741                 }
 742
 743                 return all_closing ? USER_CLOSING : USER_ONLINE;
 744         }
 745
 746         if (user_check_linger_file(u) > 0)
 747                 return USER_LINGERING;
 748
 749         return USER_CLOSING;
 750 }
 751
 752 int user_kill(User *u, int signo) {
 753         assert(u);
 754
 755         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 756 }
 757
 758 static bool elect_display_filter(Session *s) {
 759         /* Return true if the session is a candidate for the user’s ‘primary
 760          * session’ or ‘display’. */
 761         assert(s);
 762
 763         return (s->class == SESSION_USER && !s->stopping);
 764 }
 765
 766 static int elect_display_compare(Session *s1, Session *s2) {
 767         /* Indexed by SessionType. Lower numbers mean more preferred. */
 768         const int type_ranks[_SESSION_TYPE_MAX] = {
 769                 [SESSION_UNSPECIFIED] = 0,
 770                 [SESSION_TTY] = -2,
 771                 [SESSION_X11] = -3,
 772                 [SESSION_WAYLAND] = -3,
 773                 [SESSION_MIR] = -3,
 774                 [SESSION_WEB] = -1,
 775         };
 776
 777         /* Calculate the partial order relationship between s1 and s2,
 778          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 779          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 780          * is preferred.
 781          *
 782          * s1 or s2 may be NULL. */
 783         if (!s1 && !s2)
 784                 return 0;
 785
 786         if ((s1 == NULL) != (s2 == NULL))
 787                 return (s1 == NULL) - (s2 == NULL);
 788
 789         if (s1->stopping != s2->stopping)
 790                 return s1->stopping - s2->stopping;
 791
 792         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 793                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 794
 795         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 796                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 797
 798         if (s1->type != s2->type)
 799                 return type_ranks[s1->type] - type_ranks[s2->type];
 800
 801         return 0;
 802 }
 803
 804 void user_elect_display(User *u) {
 805         Session *s;
 806
 807         assert(u);
 808
 809         /* This elects a primary session for each user, which we call
 810          * the "display". We try to keep the assignment stable, but we
 811          * "upgrade" to better choices. */
 812         log_debug("Electing new display for user %s", u->name);
 813
 814         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 815                 if (!elect_display_filter(s)) {
 816                         log_debug("Ignoring session %s", s->id);
 817                         continue;
 818                 }
 819
 820                 if (elect_display_compare(s, u->display) < 0) {
 821                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 822                         u->display = s;
 823                 }
 824         }
 825 }
 826
 827 static const char* const user_state_table[_USER_STATE_MAX] = {
 828         [USER_OFFLINE] = "offline",
 829         [USER_OPENING] = "opening",
 830         [USER_LINGERING] = "lingering",
 831         [USER_ONLINE] = "online",
 832         [USER_ACTIVE] = "active",
 833         [USER_CLOSING] = "closing"
 834 };
 835
 836 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 837
 838 int config_parse_tmpfs_size(
 839                 const char* unit,
 840                 const char *filename,
 841                 unsigned line,
 842                 const char *section,
 843                 unsigned section_line,
 844                 const char *lvalue,
 845                 int ltype,
 846                 const char *rvalue,
 847                 void *data,
 848                 void *userdata) {
 849
 850         size_t *sz = data;
 851         int r;
 852
 853         assert(filename);
 854         assert(lvalue);
 855         assert(rvalue);
 856         assert(data);
 857
 858         /* First, try to parse as percentage */
 859         r = parse_percent(rvalue);
 860         if (r > 0 && r < 100)
 861                 *sz = physical_memory_scale(r, 100U);
 862         else {
 863                 uint64_t k;
 864
 865                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 866
 867                 r = parse_size(rvalue, 1024, &k);
 868                 if (r < 0 || k <= 0 || (uint64_t) (size_t) k != k) {
 869                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value, ignoring: %s", rvalue);
 870                         return 0;
 871                 }
 872
 873                 *sz = PAGE_ALIGN((size_t) k);
 874         }
 875
 876         return 0;
 877 }
 878
 879 int config_parse_user_tasks_max(
 880                 const char* unit,
 881                 const char *filename,
 882                 unsigned line,
 883                 const char *section,
 884                 unsigned section_line,
 885                 const char *lvalue,
 886                 int ltype,
 887                 const char *rvalue,
 888                 void *data,
 889                 void *userdata) {
 890
 891         uint64_t *m = data;
 892         uint64_t k;
 893         int r;
 894
 895         assert(filename);
 896         assert(lvalue);
 897         assert(rvalue);
 898         assert(data);
 899
 900         if (isempty(rvalue)) {
 901                 *m = system_tasks_max_scale(DEFAULT_USER_TASKS_MAX_PERCENTAGE, 100U);
 902                 return 0;
 903         }
 904
 905         if (streq(rvalue, "infinity")) {
 906                 *m = CGROUP_LIMIT_MAX;
 907                 return 0;
 908         }
 909
 910         /* Try to parse as percentage */
 911         r = parse_percent(rvalue);
 912         if (r >= 0)
 913                 k = system_tasks_max_scale(r, 100U);
 914         else {
 915
 916                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 917
 918                 r = safe_atou64(rvalue, &k);
 919                 if (r < 0) {
 920                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse tasks maximum, ignoring: %s", rvalue);
 921                         return 0;
 922                 }
 923         }
 924
 925         if (k <= 0 || k >= UINT64_MAX) {
 926                 log_syntax(unit, LOG_ERR, filename, line, 0, "Tasks maximum out of range, ignoring: %s", rvalue);
 927                 return 0;
 928         }
 929
 930         *m = k;
 931         return 0;
 932 }