src/login/logind-user.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdio_ext.h>
   7
   8 #include "alloc-util.h"
   9 #include "bus-common-errors.h"
  10 #include "bus-error.h"
  11 #include "bus-util.h"
  12 #include "cgroup-util.h"
  13 #include "clean-ipc.h"
  14 #include "escape.h"
  15 #include "fd-util.h"
  16 #include "fileio.h"
  17 #include "format-util.h"
  18 #include "fs-util.h"
  19 #include "hashmap.h"
  20 #include "label.h"
  21 #include "logind-user.h"
  22 #include "mkdir.h"
  23 #include "parse-util.h"
  24 #include "path-util.h"
  25 #include "rm-rf.h"
  26 #include "special.h"
  27 #include "stdio-util.h"
  28 #include "string-table.h"
  29 #include "unit-name.h"
  30 #include "user-util.h"
  31 #include "util.h"
  32
  33 int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
  34         _cleanup_(user_freep) User *u = NULL;
  35         char lu[DECIMAL_STR_MAX(uid_t) + 1];
  36         int r;
  37
  38         assert(out);
  39         assert(m);
  40         assert(name);
  41
  42         u = new0(User, 1);
  43         if (!u)
  44                 return -ENOMEM;
  45
  46         u->manager = m;
  47         u->uid = uid;
  48         u->gid = gid;
  49         xsprintf(lu, UID_FMT, uid);
  50
  51         u->name = strdup(name);
  52         if (!u->name)
  53                 return -ENOMEM;
  54
  55         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  56                 return -ENOMEM;
  57
  58         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  59                 return -ENOMEM;
  60
  61         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  62         if (r < 0)
  63                 return r;
  64
  65         r = unit_name_build("user", lu, ".service", &u->service);
  66         if (r < 0)
  67                 return r;
  68
  69         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  70         if (r < 0)
  71                 return r;
  72
  73         r = hashmap_put(m->user_units, u->slice, u);
  74         if (r < 0)
  75                 return r;
  76
  77         r = hashmap_put(m->user_units, u->service, u);
  78         if (r < 0)
  79                 return r;
  80
  81         *out = TAKE_PTR(u);
  82
  83         return 0;
  84 }
  85
  86 User *user_free(User *u) {
  87         if (!u)
  88                 return NULL;
  89
  90         if (u->in_gc_queue)
  91                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
  92
  93         while (u->sessions)
  94                 session_free(u->sessions);
  95
  96         if (u->service)
  97                 hashmap_remove_value(u->manager->user_units, u->service, u);
  98
  99         if (u->slice)
 100                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 101
 102         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 103
 104 #if 0 /// elogind neither supports slice nor service jobs.
 105         u->slice_job = mfree(u->slice_job);
 106         u->service_job = mfree(u->service_job);
 107 #endif // 0
 108
 109         u->service = mfree(u->service);
 110         u->slice = mfree(u->slice);
 111         u->runtime_path = mfree(u->runtime_path);
 112         u->state_file = mfree(u->state_file);
 113         u->name = mfree(u->name);
 114
 115         return mfree(u);
 116 }
 117
 118 static int user_save_internal(User *u) {
 119         _cleanup_free_ char *temp_path = NULL;
 120         _cleanup_fclose_ FILE *f = NULL;
 121         int r;
 122
 123         assert(u);
 124         assert(u->state_file);
 125
 126         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
 127         if (r < 0)
 128                 goto fail;
 129
 130         r = fopen_temporary(u->state_file, &f, &temp_path);
 131         if (r < 0)
 132                 goto fail;
 133
 134         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 135         (void) fchmod(fileno(f), 0644);
 136
 137         fprintf(f,
 138                 "# This is private data. Do not parse.\n"
 139                 "NAME=%s\n"
 140                 "STATE=%s\n",
 141                 u->name,
 142                 user_state_to_string(user_get_state(u)));
 143
 144         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 145         if (u->runtime_path)
 146                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 147
 148 #if 0 /// elogind neither supports service nor slice jobs
 149         if (u->service_job)
 150                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 151
 152         if (u->slice_job)
 153                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 154 #endif // 0
 155
 156         if (u->display)
 157                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 158
 159         if (dual_timestamp_is_set(&u->timestamp))
 160                 fprintf(f,
 161                         "REALTIME="USEC_FMT"\n"
 162                         "MONOTONIC="USEC_FMT"\n",
 163                         u->timestamp.realtime,
 164                         u->timestamp.monotonic);
 165
 166         if (u->sessions) {
 167                 Session *i;
 168                 bool first;
 169
 170                 fputs("SESSIONS=", f);
 171                 first = true;
 172                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 173                         if (first)
 174                                 first = false;
 175                         else
 176                                 fputc(' ', f);
 177
 178                         fputs(i->id, f);
 179                 }
 180
 181                 fputs("\nSEATS=", f);
 182                 first = true;
 183                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 184                         if (!i->seat)
 185                                 continue;
 186
 187                         if (first)
 188                                 first = false;
 189                         else
 190                                 fputc(' ', f);
 191
 192                         fputs(i->seat->id, f);
 193                 }
 194
 195                 fputs("\nACTIVE_SESSIONS=", f);
 196                 first = true;
 197                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 198                         if (!session_is_active(i))
 199                                 continue;
 200
 201                         if (first)
 202                                 first = false;
 203                         else
 204                                 fputc(' ', f);
 205
 206                         fputs(i->id, f);
 207                 }
 208
 209                 fputs("\nONLINE_SESSIONS=", f);
 210                 first = true;
 211                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 212                         if (session_get_state(i) == SESSION_CLOSING)
 213                                 continue;
 214
 215                         if (first)
 216                                 first = false;
 217                         else
 218                                 fputc(' ', f);
 219
 220                         fputs(i->id, f);
 221                 }
 222
 223                 fputs("\nACTIVE_SEATS=", f);
 224                 first = true;
 225                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 226                         if (!session_is_active(i) || !i->seat)
 227                                 continue;
 228
 229                         if (first)
 230                                 first = false;
 231                         else
 232                                 fputc(' ', f);
 233
 234                         fputs(i->seat->id, f);
 235                 }
 236
 237                 fputs("\nONLINE_SEATS=", f);
 238                 first = true;
 239                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 240                         if (session_get_state(i) == SESSION_CLOSING || !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                 fputc('\n', f);
 251         }
 252
 253         r = fflush_and_check(f);
 254         if (r < 0)
 255                 goto fail;
 256
 257         if (rename(temp_path, u->state_file) < 0) {
 258                 r = -errno;
 259                 goto fail;
 260         }
 261
 262         return 0;
 263
 264 fail:
 265         (void) unlink(u->state_file);
 266
 267         if (temp_path)
 268                 (void) unlink(temp_path);
 269
 270         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 271 }
 272
 273 int user_save(User *u) {
 274         assert(u);
 275
 276         if (!u->started)
 277                 return 0;
 278
 279         return user_save_internal (u);
 280 }
 281
 282 int user_load(User *u) {
 283         _cleanup_free_ char *display = NULL, *realtime = NULL, *monotonic = NULL;
 284         Session *s = NULL;
 285         int r;
 286
 287         assert(u);
 288
 289         r = parse_env_file(NULL, u->state_file, NEWLINE,
 290 #if 0 /// elogind neither supports service nor slice jobs
 291                            "SERVICE_JOB", &u->service_job,
 292                            "SLICE_JOB",   &u->slice_job,
 293 #endif // 0
 294                            "DISPLAY",     &display,
 295                            "REALTIME",    &realtime,
 296                            "MONOTONIC",   &monotonic,
 297                            NULL);
 298         if (r < 0) {
 299                 if (r == -ENOENT)
 300                         return 0;
 301
 302                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 303         }
 304
 305         if (display)
 306                 s = hashmap_get(u->manager->sessions, display);
 307
 308         if (s && s->display && display_is_local(s->display))
 309                 u->display = s;
 310
 311         if (realtime)
 312                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 313         if (monotonic)
 314                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 315
 316         return r;
 317 }
 318
 319
 320 static int user_start_service(User *u) {
 321 #if 0 /// elogind can not ask systemd via dbus to start user services
 322         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 323         char *job;
 324         int r;
 325
 326         assert(u);
 327
 328         u->service_job = mfree(u->service_job);
 329
 330         r = manager_start_unit(
 331                         u->manager,
 332                         u->service,
 333                         &error,
 334                         &job);
 335         if (r < 0)
 336                 /* we don't fail due to this, let's try to continue */
 337                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 338         else
 339                 u->service_job = job;
 340 #else
 341         assert(u);
 342
 343         hashmap_put(u->manager->user_units, u->service, u);
 344 #endif // 0
 345
 346         return 0;
 347 }
 348
 349 int user_start(User *u) {
 350         int r;
 351
 352         assert(u);
 353
 354         if (u->started && !u->stopping)
 355                 return 0;
 356
 357         /*
 358          * If u->stopping is set, the user is marked for removal and the slice
 359          * and service stop-jobs are queued. We have to clear that flag before
 360          * queing the start-jobs again. If they succeed, the user object can be
 361          * re-used just fine (pid1 takes care of job-ordering and proper
 362          * restart), but if they fail, we want to force another user_stop() so
 363          * possibly pending units are stopped.
 364          * Note that we don't clear u->started, as we have no clue what state
 365          * the user is in on failure here. Hence, we pretend the user is
 366          * running so it will be properly taken down by GC. However, we clearly
 367          * return an error from user_start() in that case, so no further
 368          * reference to the user is taken.
 369          */
 370         u->stopping = false;
 371
 372         if (!u->started)
 373                 log_debug("Starting services for new user %s.", u->name);
 374
 375         /* Save the user data so far, because pam_systemd will read the
 376          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 377          * We need to do user_save_internal() because we have not
 378          * "officially" started yet. */
 379         user_save_internal(u);
 380
 381         /* Spawn user systemd */
 382         r = user_start_service(u);
 383         if (r < 0)
 384                 return r;
 385
 386         if (!u->started) {
 387                 if (!dual_timestamp_is_set(&u->timestamp))
 388                         dual_timestamp_get(&u->timestamp);
 389                 user_send_signal(u, true);
 390                 u->started = true;
 391         }
 392
 393         /* Save new user data */
 394         user_save(u);
 395
 396         return 0;
 397 }
 398
 399 #if 0 /// UNNEEDED by elogind
 400 static int user_stop_slice(User *u) {
 401         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 402         char *job;
 403         int r;
 404
 405         assert(u);
 406
 407         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 408         if (r < 0) {
 409                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 410                 return r;
 411         }
 412
 413         free(u->slice_job);
 414         u->slice_job = job;
 415
 416         return r;
 417 }
 418
 419 static int user_stop_service(User *u) {
 420         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 421         char *job;
 422         int r;
 423
 424         assert(u);
 425
 426         r = manager_stop_unit(u->manager, u->service, &error, &job);
 427         if (r < 0) {
 428                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 429                 return r;
 430         }
 431
 432         free_and_replace(u->service_job, job);
 433         return r;
 434 }
 435 #endif // 0
 436
 437 int user_stop(User *u, bool force) {
 438         Session *s;
 439         int r = 0, k;
 440         assert(u);
 441
 442         /* Stop jobs have already been queued */
 443         if (u->stopping) {
 444                 user_save(u);
 445                 return r;
 446         }
 447
 448         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 449                 k = session_stop(s, force);
 450                 if (k < 0)
 451                         r = k;
 452         }
 453
 454         /* Kill systemd */
 455 #if 0 /// elogind does not support service or slice jobs
 456         k = user_stop_service(u);
 457         if (k < 0)
 458                 r = k;
 459
 460         /* Kill cgroup */
 461         k = user_stop_slice(u);
 462         if (k < 0)
 463                 r = k;
 464 #endif // 0
 465
 466         u->stopping = true;
 467
 468         user_save(u);
 469
 470 #if 1 /// elogind must queue this user again
 471         user_add_to_gc_queue(u);
 472 #endif // 1
 473         return r;
 474 }
 475
 476 int user_finalize(User *u) {
 477         Session *s;
 478         int r = 0, k;
 479
 480         assert(u);
 481
 482         if (u->started)
 483                 log_debug("User %s logged out.", u->name);
 484
 485         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 486                 k = session_finalize(s);
 487                 if (k < 0)
 488                         r = k;
 489         }
 490
 491         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 492          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 493          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 494          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 495          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 496          * and do it only for normal users. */
 497         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 498                 k = clean_ipc_by_uid(u->uid);
 499                 if (k < 0)
 500                         r = k;
 501         }
 502
 503         unlink(u->state_file);
 504         user_add_to_gc_queue(u);
 505
 506         if (u->started) {
 507                 user_send_signal(u, false);
 508                 u->started = false;
 509         }
 510
 511         return r;
 512 }
 513
 514 int user_get_idle_hint(User *u, dual_timestamp *t) {
 515         Session *s;
 516         bool idle_hint = true;
 517         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 518
 519         assert(u);
 520
 521         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 522                 dual_timestamp k;
 523                 int ih;
 524
 525                 ih = session_get_idle_hint(s, &k);
 526                 if (ih < 0)
 527                         return ih;
 528
 529                 if (!ih) {
 530                         if (!idle_hint) {
 531                                 if (k.monotonic < ts.monotonic)
 532                                         ts = k;
 533                         } else {
 534                                 idle_hint = false;
 535                                 ts = k;
 536                         }
 537                 } else if (idle_hint) {
 538
 539                         if (k.monotonic > ts.monotonic)
 540                                 ts = k;
 541                 }
 542         }
 543
 544         if (t)
 545                 *t = ts;
 546
 547         return idle_hint;
 548 }
 549
 550 int user_check_linger_file(User *u) {
 551         _cleanup_free_ char *cc = NULL;
 552         char *p = NULL;
 553
 554         cc = cescape(u->name);
 555         if (!cc)
 556                 return -ENOMEM;
 557
 558         p = strjoina("/var/lib/elogind/linger/", cc);
 559
 560         return access(p, F_OK) >= 0;
 561 }
 562
 563 bool user_may_gc(User *u, bool drop_not_started) {
 564         assert(u);
 565
 566         if (drop_not_started && !u->started)
 567                 return true;
 568
 569         if (u->sessions)
 570                 return false;
 571
 572         if (user_check_linger_file(u) > 0)
 573                 return false;
 574
 575 #if 0 /// elogind neither supports service nor slice jobs
 576         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 577                 return false;
 578
 579         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 580                 return false;
 581 #endif // 0
 582
 583         return true;
 584 }
 585
 586 void user_add_to_gc_queue(User *u) {
 587         assert(u);
 588
 589         if (u->in_gc_queue)
 590                 return;
 591
 592         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 593         u->in_gc_queue = true;
 594 }
 595
 596 UserState user_get_state(User *u) {
 597         Session *i;
 598
 599         assert(u);
 600
 601         if (u->stopping)
 602                 return USER_CLOSING;
 603
 604 #if 0 /// elogind neither supports service nor slice jobs.
 605         if (!u->started || u->slice_job || u->service_job)
 606 #else
 607         if (!u->started)
 608 #endif // 0
 609                 return USER_OPENING;
 610
 611         if (u->sessions) {
 612                 bool all_closing = true;
 613
 614                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 615                         SessionState state;
 616
 617                         state = session_get_state(i);
 618                         if (state == SESSION_ACTIVE)
 619                                 return USER_ACTIVE;
 620                         if (state != SESSION_CLOSING)
 621                                 all_closing = false;
 622                 }
 623
 624                 return all_closing ? USER_CLOSING : USER_ONLINE;
 625         }
 626
 627         if (user_check_linger_file(u) > 0)
 628                 return USER_LINGERING;
 629
 630         return USER_CLOSING;
 631 }
 632
 633 int user_kill(User *u, int signo) {
 634 #if 0 /// Without systemd unit support, elogind has to rely on its session system
 635         assert(u);
 636
 637         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 638 #else
 639         Session *s;
 640         int res = 0;
 641
 642         assert(u);
 643
 644         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 645                 int r = session_kill(s, KILL_ALL, signo);
 646                 if (res == 0 && r < 0)
 647                         res = r;
 648         }
 649
 650         return res;
 651 #endif // 0
 652 }
 653
 654 static bool elect_display_filter(Session *s) {
 655         /* Return true if the session is a candidate for the user’s ‘primary
 656          * session’ or ‘display’. */
 657         assert(s);
 658
 659         return (s->class == SESSION_USER && !s->stopping);
 660 }
 661
 662 static int elect_display_compare(Session *s1, Session *s2) {
 663         /* Indexed by SessionType. Lower numbers mean more preferred. */
 664         const int type_ranks[_SESSION_TYPE_MAX] = {
 665                 [SESSION_UNSPECIFIED] = 0,
 666                 [SESSION_TTY] = -2,
 667                 [SESSION_X11] = -3,
 668                 [SESSION_WAYLAND] = -3,
 669                 [SESSION_MIR] = -3,
 670                 [SESSION_WEB] = -1,
 671         };
 672
 673         /* Calculate the partial order relationship between s1 and s2,
 674          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 675          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 676          * is preferred.
 677          *
 678          * s1 or s2 may be NULL. */
 679         if (!s1 && !s2)
 680                 return 0;
 681
 682         if ((s1 == NULL) != (s2 == NULL))
 683                 return (s1 == NULL) - (s2 == NULL);
 684
 685         if (s1->stopping != s2->stopping)
 686                 return s1->stopping - s2->stopping;
 687
 688         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 689                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 690
 691         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 692                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 693
 694         if (s1->type != s2->type)
 695                 return type_ranks[s1->type] - type_ranks[s2->type];
 696
 697         return 0;
 698 }
 699
 700 void user_elect_display(User *u) {
 701         Session *s;
 702
 703         assert(u);
 704
 705         /* This elects a primary session for each user, which we call
 706          * the "display". We try to keep the assignment stable, but we
 707          * "upgrade" to better choices. */
 708         log_debug("Electing new display for user %s", u->name);
 709
 710         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 711                 if (!elect_display_filter(s)) {
 712                         log_debug("Ignoring session %s", s->id);
 713                         continue;
 714                 }
 715
 716                 if (elect_display_compare(s, u->display) < 0) {
 717                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 718                         u->display = s;
 719                 }
 720         }
 721 }
 722
 723 static const char* const user_state_table[_USER_STATE_MAX] = {
 724         [USER_OFFLINE] = "offline",
 725         [USER_OPENING] = "opening",
 726         [USER_LINGERING] = "lingering",
 727         [USER_ONLINE] = "online",
 728         [USER_ACTIVE] = "active",
 729         [USER_CLOSING] = "closing"
 730 };
 731
 732 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 733
 734 int config_parse_tmpfs_size(
 735                 const char* unit,
 736                 const char *filename,
 737                 unsigned line,
 738                 const char *section,
 739                 unsigned section_line,
 740                 const char *lvalue,
 741                 int ltype,
 742                 const char *rvalue,
 743                 void *data,
 744                 void *userdata) {
 745
 746         uint64_t *sz = data;
 747         int r;
 748
 749         assert(filename);
 750         assert(lvalue);
 751         assert(rvalue);
 752         assert(data);
 753
 754         /* First, try to parse as percentage */
 755         r = parse_percent(rvalue);
 756         if (r > 0 && r < 100)
 757                 *sz = physical_memory_scale(r, 100U);
 758         else {
 759                 uint64_t k;
 760
 761                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 762
 763                 r = parse_size(rvalue, 1024, &k);
 764                 if (r < 0 || k <= 0 || (uint64_t) (size_t) k != k) {
 765                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value, ignoring: %s", rvalue);
 766                         return 0;
 767                 }
 768
 769                 *sz = PAGE_ALIGN((size_t) k);
 770         }
 771
 772         return 0;
 773 }
 774
 775 int config_parse_compat_user_tasks_max(
 776                 const char *unit,
 777                 const char *filename,
 778                 unsigned line,
 779                 const char *section,
 780                 unsigned section_line,
 781                 const char *lvalue,
 782                 int ltype,
 783                 const char *rvalue,
 784                 void *data,
 785                 void *userdata) {
 786
 787         assert(filename);
 788         assert(lvalue);
 789         assert(rvalue);
 790         assert(data);
 791
 792         log_syntax(unit, LOG_NOTICE, filename, line, 0,
 793                    "Support for option %s= has been removed.",
 794                    lvalue);
 795         log_info("Hint: try creating /etc/elogind/system/user-.slice/50-limits.conf with:\n"
 796                  "        [Slice]\n"
 797                  "        TasksMax=%s",
 798                  rvalue);
 799         return 0;
 800 }