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 **ret, 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(ret);
  39         assert(m);
  40         assert(name);
  41
  42         u = new(User, 1);
  43         if (!u)
  44                 return -ENOMEM;
  45
  46         *u = (User) {
  47                 .manager = m,
  48                 .uid = uid,
  49                 .gid = gid,
  50         };
  51
  52         u->name = strdup(name);
  53         if (!u->name)
  54                 return -ENOMEM;
  55
  56         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  57                 return -ENOMEM;
  58
  59         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  60                 return -ENOMEM;
  61
  62         xsprintf(lu, UID_FMT, uid);
  63         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  64         if (r < 0)
  65                 return r;
  66
  67         r = unit_name_build("user", lu, ".service", &u->service);
  68         if (r < 0)
  69                 return r;
  70
  71         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  72         if (r < 0)
  73                 return r;
  74
  75         r = hashmap_put(m->user_units, u->slice, u);
  76         if (r < 0)
  77                 return r;
  78
  79         r = hashmap_put(m->user_units, u->service, u);
  80         if (r < 0)
  81                 return r;
  82
  83         *ret = TAKE_PTR(u);
  84         return 0;
  85 }
  86
  87 User *user_free(User *u) {
  88         if (!u)
  89                 return NULL;
  90
  91         if (u->in_gc_queue)
  92                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
  93
  94         while (u->sessions)
  95                 session_free(u->sessions);
  96
  97         if (u->service)
  98                 hashmap_remove_value(u->manager->user_units, u->service, u);
  99
 100         if (u->slice)
 101                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 102
 103         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 104
 105         u->slice_job = mfree(u->slice_job);
 106         u->service_job = mfree(u->service_job);
 107
 108         u->service = mfree(u->service);
 109         u->slice = mfree(u->slice);
 110         u->runtime_path = mfree(u->runtime_path);
 111         u->state_file = mfree(u->state_file);
 112         u->name = mfree(u->name);
 113
 114         return mfree(u);
 115 }
 116
 117 static int user_save_internal(User *u) {
 118         _cleanup_free_ char *temp_path = NULL;
 119         _cleanup_fclose_ FILE *f = NULL;
 120         int r;
 121
 122         assert(u);
 123         assert(u->state_file);
 124
 125         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
 126         if (r < 0)
 127                 goto fail;
 128
 129         r = fopen_temporary(u->state_file, &f, &temp_path);
 130         if (r < 0)
 131                 goto fail;
 132
 133         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 134         (void) fchmod(fileno(f), 0644);
 135
 136         fprintf(f,
 137                 "# This is private data. Do not parse.\n"
 138                 "NAME=%s\n"
 139                 "STATE=%s\n",
 140                 u->name,
 141                 user_state_to_string(user_get_state(u)));
 142
 143         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 144         if (u->runtime_path)
 145                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 146
 147         if (u->service_job)
 148                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 149
 150         if (u->slice_job)
 151                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 152
 153         if (u->display)
 154                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 155
 156         if (dual_timestamp_is_set(&u->timestamp))
 157                 fprintf(f,
 158                         "REALTIME="USEC_FMT"\n"
 159                         "MONOTONIC="USEC_FMT"\n",
 160                         u->timestamp.realtime,
 161                         u->timestamp.monotonic);
 162
 163         if (u->sessions) {
 164                 Session *i;
 165                 bool first;
 166
 167                 fputs("SESSIONS=", f);
 168                 first = true;
 169                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 170                         if (first)
 171                                 first = false;
 172                         else
 173                                 fputc(' ', f);
 174
 175                         fputs(i->id, f);
 176                 }
 177
 178                 fputs("\nSEATS=", f);
 179                 first = true;
 180                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 181                         if (!i->seat)
 182                                 continue;
 183
 184                         if (first)
 185                                 first = false;
 186                         else
 187                                 fputc(' ', f);
 188
 189                         fputs(i->seat->id, f);
 190                 }
 191
 192                 fputs("\nACTIVE_SESSIONS=", f);
 193                 first = true;
 194                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 195                         if (!session_is_active(i))
 196                                 continue;
 197
 198                         if (first)
 199                                 first = false;
 200                         else
 201                                 fputc(' ', f);
 202
 203                         fputs(i->id, f);
 204                 }
 205
 206                 fputs("\nONLINE_SESSIONS=", f);
 207                 first = true;
 208                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 209                         if (session_get_state(i) == SESSION_CLOSING)
 210                                 continue;
 211
 212                         if (first)
 213                                 first = false;
 214                         else
 215                                 fputc(' ', f);
 216
 217                         fputs(i->id, f);
 218                 }
 219
 220                 fputs("\nACTIVE_SEATS=", f);
 221                 first = true;
 222                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 223                         if (!session_is_active(i) || !i->seat)
 224                                 continue;
 225
 226                         if (first)
 227                                 first = false;
 228                         else
 229                                 fputc(' ', f);
 230
 231                         fputs(i->seat->id, f);
 232                 }
 233
 234                 fputs("\nONLINE_SEATS=", f);
 235                 first = true;
 236                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 237                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 238                                 continue;
 239
 240                         if (first)
 241                                 first = false;
 242                         else
 243                                 fputc(' ', f);
 244
 245                         fputs(i->seat->id, f);
 246                 }
 247                 fputc('\n', f);
 248         }
 249
 250         r = fflush_and_check(f);
 251         if (r < 0)
 252                 goto fail;
 253
 254         if (rename(temp_path, u->state_file) < 0) {
 255                 r = -errno;
 256                 goto fail;
 257         }
 258
 259         return 0;
 260
 261 fail:
 262         (void) unlink(u->state_file);
 263
 264         if (temp_path)
 265                 (void) unlink(temp_path);
 266
 267         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 268 }
 269
 270 int user_save(User *u) {
 271         assert(u);
 272
 273         if (!u->started)
 274                 return 0;
 275
 276         return user_save_internal(u);
 277 }
 278
 279 int user_load(User *u) {
 280         _cleanup_free_ char *realtime = NULL, *monotonic = NULL;
 281         int r;
 282
 283         assert(u);
 284
 285         r = parse_env_file(NULL, u->state_file, NEWLINE,
 286                            "SERVICE_JOB", &u->service_job,
 287                            "SLICE_JOB",   &u->slice_job,
 288                            "REALTIME",    &realtime,
 289                            "MONOTONIC",   &monotonic,
 290                            NULL);
 291         if (r == -ENOENT)
 292                 return 0;
 293         if (r < 0)
 294                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 295
 296         if (realtime)
 297                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 298         if (monotonic)
 299                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 300
 301         return r;
 302 }
 303
 304 static int user_start_service(User *u) {
 305         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 306         char *job;
 307         int r;
 308
 309         assert(u);
 310
 311         u->service_job = mfree(u->service_job);
 312
 313         r = manager_start_unit(
 314                         u->manager,
 315                         u->service,
 316                         &error,
 317                         &job);
 318         if (r < 0)
 319                 /* we don't fail due to this, let's try to continue */
 320                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 321         else
 322                 u->service_job = job;
 323
 324         return 0;
 325 }
 326
 327 int user_start(User *u) {
 328         int r;
 329
 330         assert(u);
 331
 332         if (u->started && !u->stopping)
 333                 return 0;
 334
 335         /*
 336          * If u->stopping is set, the user is marked for removal and the slice
 337          * and service stop-jobs are queued. We have to clear that flag before
 338          * queing the start-jobs again. If they succeed, the user object can be
 339          * re-used just fine (pid1 takes care of job-ordering and proper
 340          * restart), but if they fail, we want to force another user_stop() so
 341          * possibly pending units are stopped.
 342          * Note that we don't clear u->started, as we have no clue what state
 343          * the user is in on failure here. Hence, we pretend the user is
 344          * running so it will be properly taken down by GC. However, we clearly
 345          * return an error from user_start() in that case, so no further
 346          * reference to the user is taken.
 347          */
 348         u->stopping = false;
 349
 350         if (!u->started)
 351                 log_debug("Starting services for new user %s.", u->name);
 352
 353         /* Save the user data so far, because pam_systemd will read the
 354          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 355          * We need to do user_save_internal() because we have not
 356          * "officially" started yet. */
 357         user_save_internal(u);
 358
 359         /* Spawn user systemd */
 360         r = user_start_service(u);
 361         if (r < 0)
 362                 return r;
 363
 364         if (!u->started) {
 365                 if (!dual_timestamp_is_set(&u->timestamp))
 366                         dual_timestamp_get(&u->timestamp);
 367                 user_send_signal(u, true);
 368                 u->started = true;
 369         }
 370
 371         /* Save new user data */
 372         user_save(u);
 373
 374         return 0;
 375 }
 376
 377 static int user_stop_slice(User *u) {
 378         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 379         char *job;
 380         int r;
 381
 382         assert(u);
 383
 384         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 385         if (r < 0)
 386                 return log_error_errno(r, "Failed to stop user slice: %s", bus_error_message(&error, r));
 387
 388         return free_and_replace(u->slice_job, job);
 389 }
 390
 391 static int user_stop_service(User *u) {
 392         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 393         char *job;
 394         int r;
 395
 396         assert(u);
 397
 398         r = manager_stop_unit(u->manager, u->service, &error, &job);
 399         if (r < 0)
 400                 return log_error_errno(r, "Failed to stop user service: %s", bus_error_message(&error, r));
 401
 402         return free_and_replace(u->service_job, job);
 403 }
 404
 405 int user_stop(User *u, bool force) {
 406         Session *s;
 407         int r = 0, k;
 408         assert(u);
 409
 410         /* Stop jobs have already been queued */
 411         if (u->stopping) {
 412                 user_save(u);
 413                 return r;
 414         }
 415
 416         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 417                 k = session_stop(s, force);
 418                 if (k < 0)
 419                         r = k;
 420         }
 421
 422         /* Kill systemd */
 423         k = user_stop_service(u);
 424         if (k < 0)
 425                 r = k;
 426
 427         /* Kill cgroup */
 428         k = user_stop_slice(u);
 429         if (k < 0)
 430                 r = k;
 431
 432         u->stopping = true;
 433
 434         user_save(u);
 435
 436         return r;
 437 }
 438
 439 int user_finalize(User *u) {
 440         Session *s;
 441         int r = 0, k;
 442
 443         assert(u);
 444
 445         if (u->started)
 446                 log_debug("User %s logged out.", u->name);
 447
 448         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 449                 k = session_finalize(s);
 450                 if (k < 0)
 451                         r = k;
 452         }
 453
 454         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 455          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 456          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 457          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 458          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 459          * and do it only for normal users. */
 460         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 461                 k = clean_ipc_by_uid(u->uid);
 462                 if (k < 0)
 463                         r = k;
 464         }
 465
 466         unlink(u->state_file);
 467         user_add_to_gc_queue(u);
 468
 469         if (u->started) {
 470                 user_send_signal(u, false);
 471                 u->started = false;
 472         }
 473
 474         return r;
 475 }
 476
 477 int user_get_idle_hint(User *u, dual_timestamp *t) {
 478         Session *s;
 479         bool idle_hint = true;
 480         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 481
 482         assert(u);
 483
 484         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 485                 dual_timestamp k;
 486                 int ih;
 487
 488                 ih = session_get_idle_hint(s, &k);
 489                 if (ih < 0)
 490                         return ih;
 491
 492                 if (!ih) {
 493                         if (!idle_hint) {
 494                                 if (k.monotonic < ts.monotonic)
 495                                         ts = k;
 496                         } else {
 497                                 idle_hint = false;
 498                                 ts = k;
 499                         }
 500                 } else if (idle_hint) {
 501
 502                         if (k.monotonic > ts.monotonic)
 503                                 ts = k;
 504                 }
 505         }
 506
 507         if (t)
 508                 *t = ts;
 509
 510         return idle_hint;
 511 }
 512
 513 int user_check_linger_file(User *u) {
 514         _cleanup_free_ char *cc = NULL;
 515         char *p = NULL;
 516
 517         cc = cescape(u->name);
 518         if (!cc)
 519                 return -ENOMEM;
 520
 521         p = strjoina("/var/lib/systemd/linger/", cc);
 522
 523         return access(p, F_OK) >= 0;
 524 }
 525
 526 bool user_may_gc(User *u, bool drop_not_started) {
 527         assert(u);
 528
 529         if (drop_not_started && !u->started)
 530                 return true;
 531
 532         if (u->sessions)
 533                 return false;
 534
 535         if (user_check_linger_file(u) > 0)
 536                 return false;
 537
 538         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 539                 return false;
 540
 541         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 542                 return false;
 543
 544         return true;
 545 }
 546
 547 void user_add_to_gc_queue(User *u) {
 548         assert(u);
 549
 550         if (u->in_gc_queue)
 551                 return;
 552
 553         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 554         u->in_gc_queue = true;
 555 }
 556
 557 UserState user_get_state(User *u) {
 558         Session *i;
 559
 560         assert(u);
 561
 562         if (u->stopping)
 563                 return USER_CLOSING;
 564
 565         if (!u->started || u->slice_job || u->service_job)
 566                 return USER_OPENING;
 567
 568         if (u->sessions) {
 569                 bool all_closing = true;
 570
 571                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 572                         SessionState state;
 573
 574                         state = session_get_state(i);
 575                         if (state == SESSION_ACTIVE)
 576                                 return USER_ACTIVE;
 577                         if (state != SESSION_CLOSING)
 578                                 all_closing = false;
 579                 }
 580
 581                 return all_closing ? USER_CLOSING : USER_ONLINE;
 582         }
 583
 584         if (user_check_linger_file(u) > 0)
 585                 return USER_LINGERING;
 586
 587         return USER_CLOSING;
 588 }
 589
 590 int user_kill(User *u, int signo) {
 591         assert(u);
 592
 593         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 594 }
 595
 596 static bool elect_display_filter(Session *s) {
 597         /* Return true if the session is a candidate for the user’s ‘primary
 598          * session’ or ‘display’. */
 599         assert(s);
 600
 601         return (s->class == SESSION_USER && !s->stopping);
 602 }
 603
 604 static int elect_display_compare(Session *s1, Session *s2) {
 605         /* Indexed by SessionType. Lower numbers mean more preferred. */
 606         const int type_ranks[_SESSION_TYPE_MAX] = {
 607                 [SESSION_UNSPECIFIED] = 0,
 608                 [SESSION_TTY] = -2,
 609                 [SESSION_X11] = -3,
 610                 [SESSION_WAYLAND] = -3,
 611                 [SESSION_MIR] = -3,
 612                 [SESSION_WEB] = -1,
 613         };
 614
 615         /* Calculate the partial order relationship between s1 and s2,
 616          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 617          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 618          * is preferred.
 619          *
 620          * s1 or s2 may be NULL. */
 621         if (!s1 && !s2)
 622                 return 0;
 623
 624         if ((s1 == NULL) != (s2 == NULL))
 625                 return (s1 == NULL) - (s2 == NULL);
 626
 627         if (s1->stopping != s2->stopping)
 628                 return s1->stopping - s2->stopping;
 629
 630         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 631                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 632
 633         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 634                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 635
 636         if (s1->type != s2->type)
 637                 return type_ranks[s1->type] - type_ranks[s2->type];
 638
 639         return 0;
 640 }
 641
 642 void user_elect_display(User *u) {
 643         Session *s;
 644
 645         assert(u);
 646
 647         /* This elects a primary session for each user, which we call
 648          * the "display". We try to keep the assignment stable, but we
 649          * "upgrade" to better choices. */
 650         log_debug("Electing new display for user %s", u->name);
 651
 652         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 653                 if (!elect_display_filter(s)) {
 654                         log_debug("Ignoring session %s", s->id);
 655                         continue;
 656                 }
 657
 658                 if (elect_display_compare(s, u->display) < 0) {
 659                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 660                         u->display = s;
 661                 }
 662         }
 663 }
 664
 665 static const char* const user_state_table[_USER_STATE_MAX] = {
 666         [USER_OFFLINE] = "offline",
 667         [USER_OPENING] = "opening",
 668         [USER_LINGERING] = "lingering",
 669         [USER_ONLINE] = "online",
 670         [USER_ACTIVE] = "active",
 671         [USER_CLOSING] = "closing"
 672 };
 673
 674 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 675
 676 int config_parse_tmpfs_size(
 677                 const char* unit,
 678                 const char *filename,
 679                 unsigned line,
 680                 const char *section,
 681                 unsigned section_line,
 682                 const char *lvalue,
 683                 int ltype,
 684                 const char *rvalue,
 685                 void *data,
 686                 void *userdata) {
 687
 688         uint64_t *sz = data;
 689         int r;
 690
 691         assert(filename);
 692         assert(lvalue);
 693         assert(rvalue);
 694         assert(data);
 695
 696         /* First, try to parse as percentage */
 697         r = parse_permille(rvalue);
 698         if (r > 0 && r < 1000)
 699                 *sz = physical_memory_scale(r, 1000U);
 700         else {
 701                 uint64_t k;
 702
 703                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 704
 705                 r = parse_size(rvalue, 1024, &k);
 706                 if (r >= 0 && (k <= 0 || (uint64_t) (size_t) k != k))
 707                         r = -ERANGE;
 708                 if (r < 0) {
 709                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value '%s', ignoring: %m", rvalue);
 710                         return 0;
 711                 }
 712
 713                 *sz = PAGE_ALIGN((size_t) k);
 714         }
 715
 716         return 0;
 717 }
 718
 719 int config_parse_compat_user_tasks_max(
 720                 const char *unit,
 721                 const char *filename,
 722                 unsigned line,
 723                 const char *section,
 724                 unsigned section_line,
 725                 const char *lvalue,
 726                 int ltype,
 727                 const char *rvalue,
 728                 void *data,
 729                 void *userdata) {
 730
 731         assert(filename);
 732         assert(lvalue);
 733         assert(rvalue);
 734         assert(data);
 735
 736         log_syntax(unit, LOG_NOTICE, filename, line, 0,
 737                    "Support for option %s= has been removed.",
 738                    lvalue);
 739         log_info("Hint: try creating /etc/systemd/system/user-.slice.d/50-limits.conf with:\n"
 740                  "        [Slice]\n"
 741                  "        TasksMax=%s",
 742                  rvalue);
 743         return 0;
 744 }