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         u->slice_job = mfree(u->slice_job);
 105         u->service_job = mfree(u->service_job);
 106
 107         u->service = mfree(u->service);
 108         u->slice = mfree(u->slice);
 109         u->runtime_path = mfree(u->runtime_path);
 110         u->state_file = mfree(u->state_file);
 111         u->name = mfree(u->name);
 112
 113         return mfree(u);
 114 }
 115
 116 static int user_save_internal(User *u) {
 117         _cleanup_free_ char *temp_path = NULL;
 118         _cleanup_fclose_ FILE *f = NULL;
 119         int r;
 120
 121         assert(u);
 122         assert(u->state_file);
 123
 124         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
 125         if (r < 0)
 126                 goto fail;
 127
 128         r = fopen_temporary(u->state_file, &f, &temp_path);
 129         if (r < 0)
 130                 goto fail;
 131
 132         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 133         (void) fchmod(fileno(f), 0644);
 134
 135         fprintf(f,
 136                 "# This is private data. Do not parse.\n"
 137                 "NAME=%s\n"
 138                 "STATE=%s\n",
 139                 u->name,
 140                 user_state_to_string(user_get_state(u)));
 141
 142         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 143         if (u->runtime_path)
 144                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 145
 146         if (u->service_job)
 147                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 148
 149         if (u->slice_job)
 150                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 151
 152         if (u->display)
 153                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 154
 155         if (dual_timestamp_is_set(&u->timestamp))
 156                 fprintf(f,
 157                         "REALTIME="USEC_FMT"\n"
 158                         "MONOTONIC="USEC_FMT"\n",
 159                         u->timestamp.realtime,
 160                         u->timestamp.monotonic);
 161
 162         if (u->sessions) {
 163                 Session *i;
 164                 bool first;
 165
 166                 fputs("SESSIONS=", f);
 167                 first = true;
 168                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 169                         if (first)
 170                                 first = false;
 171                         else
 172                                 fputc(' ', f);
 173
 174                         fputs(i->id, f);
 175                 }
 176
 177                 fputs("\nSEATS=", f);
 178                 first = true;
 179                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 180                         if (!i->seat)
 181                                 continue;
 182
 183                         if (first)
 184                                 first = false;
 185                         else
 186                                 fputc(' ', f);
 187
 188                         fputs(i->seat->id, f);
 189                 }
 190
 191                 fputs("\nACTIVE_SESSIONS=", f);
 192                 first = true;
 193                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 194                         if (!session_is_active(i))
 195                                 continue;
 196
 197                         if (first)
 198                                 first = false;
 199                         else
 200                                 fputc(' ', f);
 201
 202                         fputs(i->id, f);
 203                 }
 204
 205                 fputs("\nONLINE_SESSIONS=", f);
 206                 first = true;
 207                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 208                         if (session_get_state(i) == SESSION_CLOSING)
 209                                 continue;
 210
 211                         if (first)
 212                                 first = false;
 213                         else
 214                                 fputc(' ', f);
 215
 216                         fputs(i->id, f);
 217                 }
 218
 219                 fputs("\nACTIVE_SEATS=", f);
 220                 first = true;
 221                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 222                         if (!session_is_active(i) || !i->seat)
 223                                 continue;
 224
 225                         if (first)
 226                                 first = false;
 227                         else
 228                                 fputc(' ', f);
 229
 230                         fputs(i->seat->id, f);
 231                 }
 232
 233                 fputs("\nONLINE_SEATS=", f);
 234                 first = true;
 235                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 236                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 237                                 continue;
 238
 239                         if (first)
 240                                 first = false;
 241                         else
 242                                 fputc(' ', f);
 243
 244                         fputs(i->seat->id, f);
 245                 }
 246                 fputc('\n', f);
 247         }
 248
 249         r = fflush_and_check(f);
 250         if (r < 0)
 251                 goto fail;
 252
 253         if (rename(temp_path, u->state_file) < 0) {
 254                 r = -errno;
 255                 goto fail;
 256         }
 257
 258         return 0;
 259
 260 fail:
 261         (void) unlink(u->state_file);
 262
 263         if (temp_path)
 264                 (void) unlink(temp_path);
 265
 266         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 267 }
 268
 269 int user_save(User *u) {
 270         assert(u);
 271
 272         if (!u->started)
 273                 return 0;
 274
 275         return user_save_internal (u);
 276 }
 277
 278 int user_load(User *u) {
 279         _cleanup_free_ char *display = NULL, *realtime = NULL, *monotonic = NULL;
 280         Session *s = 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                            "DISPLAY",     &display,
 289                            "REALTIME",    &realtime,
 290                            "MONOTONIC",   &monotonic,
 291                            NULL);
 292         if (r < 0) {
 293                 if (r == -ENOENT)
 294                         return 0;
 295
 296                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 297         }
 298
 299         if (display)
 300                 s = hashmap_get(u->manager->sessions, display);
 301
 302         if (s && s->display && display_is_local(s->display))
 303                 u->display = s;
 304
 305         if (realtime)
 306                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 307         if (monotonic)
 308                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 309
 310         return r;
 311 }
 312
 313 static int user_start_service(User *u) {
 314         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 315         char *job;
 316         int r;
 317
 318         assert(u);
 319
 320         u->service_job = mfree(u->service_job);
 321
 322         r = manager_start_unit(
 323                         u->manager,
 324                         u->service,
 325                         &error,
 326                         &job);
 327         if (r < 0)
 328                 /* we don't fail due to this, let's try to continue */
 329                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 330         else
 331                 u->service_job = job;
 332
 333         return 0;
 334 }
 335
 336 int user_start(User *u) {
 337         int r;
 338
 339         assert(u);
 340
 341         if (u->started && !u->stopping)
 342                 return 0;
 343
 344         /*
 345          * If u->stopping is set, the user is marked for removal and the slice
 346          * and service stop-jobs are queued. We have to clear that flag before
 347          * queing the start-jobs again. If they succeed, the user object can be
 348          * re-used just fine (pid1 takes care of job-ordering and proper
 349          * restart), but if they fail, we want to force another user_stop() so
 350          * possibly pending units are stopped.
 351          * Note that we don't clear u->started, as we have no clue what state
 352          * the user is in on failure here. Hence, we pretend the user is
 353          * running so it will be properly taken down by GC. However, we clearly
 354          * return an error from user_start() in that case, so no further
 355          * reference to the user is taken.
 356          */
 357         u->stopping = false;
 358
 359         if (!u->started)
 360                 log_debug("Starting services for new user %s.", u->name);
 361
 362         /* Save the user data so far, because pam_systemd will read the
 363          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 364          * We need to do user_save_internal() because we have not
 365          * "officially" started yet. */
 366         user_save_internal(u);
 367
 368         /* Spawn user systemd */
 369         r = user_start_service(u);
 370         if (r < 0)
 371                 return r;
 372
 373         if (!u->started) {
 374                 if (!dual_timestamp_is_set(&u->timestamp))
 375                         dual_timestamp_get(&u->timestamp);
 376                 user_send_signal(u, true);
 377                 u->started = true;
 378         }
 379
 380         /* Save new user data */
 381         user_save(u);
 382
 383         return 0;
 384 }
 385
 386 static int user_stop_slice(User *u) {
 387         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 388         char *job;
 389         int r;
 390
 391         assert(u);
 392
 393         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 394         if (r < 0) {
 395                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 396                 return r;
 397         }
 398
 399         free(u->slice_job);
 400         u->slice_job = job;
 401
 402         return r;
 403 }
 404
 405 static int user_stop_service(User *u) {
 406         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 407         char *job;
 408         int r;
 409
 410         assert(u);
 411
 412         r = manager_stop_unit(u->manager, u->service, &error, &job);
 413         if (r < 0) {
 414                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 415                 return r;
 416         }
 417
 418         free_and_replace(u->service_job, job);
 419         return r;
 420 }
 421
 422 int user_stop(User *u, bool force) {
 423         Session *s;
 424         int r = 0, k;
 425         assert(u);
 426
 427         /* Stop jobs have already been queued */
 428         if (u->stopping) {
 429                 user_save(u);
 430                 return r;
 431         }
 432
 433         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 434                 k = session_stop(s, force);
 435                 if (k < 0)
 436                         r = k;
 437         }
 438
 439         /* Kill systemd */
 440         k = user_stop_service(u);
 441         if (k < 0)
 442                 r = k;
 443
 444         /* Kill cgroup */
 445         k = user_stop_slice(u);
 446         if (k < 0)
 447                 r = k;
 448
 449         u->stopping = true;
 450
 451         user_save(u);
 452
 453         return r;
 454 }
 455
 456 int user_finalize(User *u) {
 457         Session *s;
 458         int r = 0, k;
 459
 460         assert(u);
 461
 462         if (u->started)
 463                 log_debug("User %s logged out.", u->name);
 464
 465         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 466                 k = session_finalize(s);
 467                 if (k < 0)
 468                         r = k;
 469         }
 470
 471         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 472          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 473          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 474          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 475          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 476          * and do it only for normal users. */
 477         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 478                 k = clean_ipc_by_uid(u->uid);
 479                 if (k < 0)
 480                         r = k;
 481         }
 482
 483         unlink(u->state_file);
 484         user_add_to_gc_queue(u);
 485
 486         if (u->started) {
 487                 user_send_signal(u, false);
 488                 u->started = false;
 489         }
 490
 491         return r;
 492 }
 493
 494 int user_get_idle_hint(User *u, dual_timestamp *t) {
 495         Session *s;
 496         bool idle_hint = true;
 497         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 498
 499         assert(u);
 500
 501         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 502                 dual_timestamp k;
 503                 int ih;
 504
 505                 ih = session_get_idle_hint(s, &k);
 506                 if (ih < 0)
 507                         return ih;
 508
 509                 if (!ih) {
 510                         if (!idle_hint) {
 511                                 if (k.monotonic < ts.monotonic)
 512                                         ts = k;
 513                         } else {
 514                                 idle_hint = false;
 515                                 ts = k;
 516                         }
 517                 } else if (idle_hint) {
 518
 519                         if (k.monotonic > ts.monotonic)
 520                                 ts = k;
 521                 }
 522         }
 523
 524         if (t)
 525                 *t = ts;
 526
 527         return idle_hint;
 528 }
 529
 530 int user_check_linger_file(User *u) {
 531         _cleanup_free_ char *cc = NULL;
 532         char *p = NULL;
 533
 534         cc = cescape(u->name);
 535         if (!cc)
 536                 return -ENOMEM;
 537
 538         p = strjoina("/var/lib/systemd/linger/", cc);
 539
 540         return access(p, F_OK) >= 0;
 541 }
 542
 543 bool user_may_gc(User *u, bool drop_not_started) {
 544         assert(u);
 545
 546         if (drop_not_started && !u->started)
 547                 return true;
 548
 549         if (u->sessions)
 550                 return false;
 551
 552         if (user_check_linger_file(u) > 0)
 553                 return false;
 554
 555         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 556                 return false;
 557
 558         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 559                 return false;
 560
 561         return true;
 562 }
 563
 564 void user_add_to_gc_queue(User *u) {
 565         assert(u);
 566
 567         if (u->in_gc_queue)
 568                 return;
 569
 570         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 571         u->in_gc_queue = true;
 572 }
 573
 574 UserState user_get_state(User *u) {
 575         Session *i;
 576
 577         assert(u);
 578
 579         if (u->stopping)
 580                 return USER_CLOSING;
 581
 582         if (!u->started || u->slice_job || u->service_job)
 583                 return USER_OPENING;
 584
 585         if (u->sessions) {
 586                 bool all_closing = true;
 587
 588                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 589                         SessionState state;
 590
 591                         state = session_get_state(i);
 592                         if (state == SESSION_ACTIVE)
 593                                 return USER_ACTIVE;
 594                         if (state != SESSION_CLOSING)
 595                                 all_closing = false;
 596                 }
 597
 598                 return all_closing ? USER_CLOSING : USER_ONLINE;
 599         }
 600
 601         if (user_check_linger_file(u) > 0)
 602                 return USER_LINGERING;
 603
 604         return USER_CLOSING;
 605 }
 606
 607 int user_kill(User *u, int signo) {
 608         assert(u);
 609
 610         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 611 }
 612
 613 static bool elect_display_filter(Session *s) {
 614         /* Return true if the session is a candidate for the user’s ‘primary
 615          * session’ or ‘display’. */
 616         assert(s);
 617
 618         return (s->class == SESSION_USER && !s->stopping);
 619 }
 620
 621 static int elect_display_compare(Session *s1, Session *s2) {
 622         /* Indexed by SessionType. Lower numbers mean more preferred. */
 623         const int type_ranks[_SESSION_TYPE_MAX] = {
 624                 [SESSION_UNSPECIFIED] = 0,
 625                 [SESSION_TTY] = -2,
 626                 [SESSION_X11] = -3,
 627                 [SESSION_WAYLAND] = -3,
 628                 [SESSION_MIR] = -3,
 629                 [SESSION_WEB] = -1,
 630         };
 631
 632         /* Calculate the partial order relationship between s1 and s2,
 633          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 634          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 635          * is preferred.
 636          *
 637          * s1 or s2 may be NULL. */
 638         if (!s1 && !s2)
 639                 return 0;
 640
 641         if ((s1 == NULL) != (s2 == NULL))
 642                 return (s1 == NULL) - (s2 == NULL);
 643
 644         if (s1->stopping != s2->stopping)
 645                 return s1->stopping - s2->stopping;
 646
 647         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 648                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 649
 650         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 651                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 652
 653         if (s1->type != s2->type)
 654                 return type_ranks[s1->type] - type_ranks[s2->type];
 655
 656         return 0;
 657 }
 658
 659 void user_elect_display(User *u) {
 660         Session *s;
 661
 662         assert(u);
 663
 664         /* This elects a primary session for each user, which we call
 665          * the "display". We try to keep the assignment stable, but we
 666          * "upgrade" to better choices. */
 667         log_debug("Electing new display for user %s", u->name);
 668
 669         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 670                 if (!elect_display_filter(s)) {
 671                         log_debug("Ignoring session %s", s->id);
 672                         continue;
 673                 }
 674
 675                 if (elect_display_compare(s, u->display) < 0) {
 676                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 677                         u->display = s;
 678                 }
 679         }
 680 }
 681
 682 static const char* const user_state_table[_USER_STATE_MAX] = {
 683         [USER_OFFLINE] = "offline",
 684         [USER_OPENING] = "opening",
 685         [USER_LINGERING] = "lingering",
 686         [USER_ONLINE] = "online",
 687         [USER_ACTIVE] = "active",
 688         [USER_CLOSING] = "closing"
 689 };
 690
 691 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 692
 693 int config_parse_tmpfs_size(
 694                 const char* unit,
 695                 const char *filename,
 696                 unsigned line,
 697                 const char *section,
 698                 unsigned section_line,
 699                 const char *lvalue,
 700                 int ltype,
 701                 const char *rvalue,
 702                 void *data,
 703                 void *userdata) {
 704
 705         uint64_t *sz = data;
 706         int r;
 707
 708         assert(filename);
 709         assert(lvalue);
 710         assert(rvalue);
 711         assert(data);
 712
 713         /* First, try to parse as percentage */
 714         r = parse_permille(rvalue);
 715         if (r > 0 && r < 1000)
 716                 *sz = physical_memory_scale(r, 1000U);
 717         else {
 718                 uint64_t k;
 719
 720                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 721
 722                 r = parse_size(rvalue, 1024, &k);
 723                 if (r >= 0 && (k <= 0 || (uint64_t) (size_t) k != k))
 724                         r = -ERANGE;
 725                 if (r < 0) {
 726                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value '%s', ignoring: %m", rvalue);
 727                         return 0;
 728                 }
 729
 730                 *sz = PAGE_ALIGN((size_t) k);
 731         }
 732
 733         return 0;
 734 }
 735
 736 int config_parse_compat_user_tasks_max(
 737                 const char *unit,
 738                 const char *filename,
 739                 unsigned line,
 740                 const char *section,
 741                 unsigned section_line,
 742                 const char *lvalue,
 743                 int ltype,
 744                 const char *rvalue,
 745                 void *data,
 746                 void *userdata) {
 747
 748         assert(filename);
 749         assert(lvalue);
 750         assert(rvalue);
 751         assert(data);
 752
 753         log_syntax(unit, LOG_NOTICE, filename, line, 0,
 754                    "Support for option %s= has been removed.",
 755                    lvalue);
 756         log_info("Hint: try creating /etc/systemd/system/user-.slice.d/50-limits.conf with:\n"
 757                  "        [Slice]\n"
 758                  "        TasksMax=%s",
 759                  rvalue);
 760         return 0;
 761 }