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"         /* friendly user-facing state */
 140                 "STOPPING=%s\n",     /* low-level state */
 141                 u->name,
 142                 user_state_to_string(user_get_state(u)),
 143                 yes_no(u->stopping));
 144
 145         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 146         if (u->runtime_path)
 147                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 148
 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
 155         if (u->display)
 156                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 157
 158         if (dual_timestamp_is_set(&u->timestamp))
 159                 fprintf(f,
 160                         "REALTIME="USEC_FMT"\n"
 161                         "MONOTONIC="USEC_FMT"\n",
 162                         u->timestamp.realtime,
 163                         u->timestamp.monotonic);
 164
 165         if (u->sessions) {
 166                 Session *i;
 167                 bool first;
 168
 169                 fputs("SESSIONS=", f);
 170                 first = true;
 171                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 172                         if (first)
 173                                 first = false;
 174                         else
 175                                 fputc(' ', f);
 176
 177                         fputs(i->id, f);
 178                 }
 179
 180                 fputs("\nSEATS=", f);
 181                 first = true;
 182                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 183                         if (!i->seat)
 184                                 continue;
 185
 186                         if (first)
 187                                 first = false;
 188                         else
 189                                 fputc(' ', f);
 190
 191                         fputs(i->seat->id, f);
 192                 }
 193
 194                 fputs("\nACTIVE_SESSIONS=", f);
 195                 first = true;
 196                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 197                         if (!session_is_active(i))
 198                                 continue;
 199
 200                         if (first)
 201                                 first = false;
 202                         else
 203                                 fputc(' ', f);
 204
 205                         fputs(i->id, f);
 206                 }
 207
 208                 fputs("\nONLINE_SESSIONS=", f);
 209                 first = true;
 210                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 211                         if (session_get_state(i) == SESSION_CLOSING)
 212                                 continue;
 213
 214                         if (first)
 215                                 first = false;
 216                         else
 217                                 fputc(' ', f);
 218
 219                         fputs(i->id, f);
 220                 }
 221
 222                 fputs("\nACTIVE_SEATS=", f);
 223                 first = true;
 224                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 225                         if (!session_is_active(i) || !i->seat)
 226                                 continue;
 227
 228                         if (first)
 229                                 first = false;
 230                         else
 231                                 fputc(' ', f);
 232
 233                         fputs(i->seat->id, f);
 234                 }
 235
 236                 fputs("\nONLINE_SEATS=", f);
 237                 first = true;
 238                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 239                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 240                                 continue;
 241
 242                         if (first)
 243                                 first = false;
 244                         else
 245                                 fputc(' ', f);
 246
 247                         fputs(i->seat->id, f);
 248                 }
 249                 fputc('\n', f);
 250         }
 251
 252         r = fflush_and_check(f);
 253         if (r < 0)
 254                 goto fail;
 255
 256         if (rename(temp_path, u->state_file) < 0) {
 257                 r = -errno;
 258                 goto fail;
 259         }
 260
 261         return 0;
 262
 263 fail:
 264         (void) unlink(u->state_file);
 265
 266         if (temp_path)
 267                 (void) unlink(temp_path);
 268
 269         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 270 }
 271
 272 int user_save(User *u) {
 273         assert(u);
 274
 275         if (!u->started)
 276                 return 0;
 277
 278         return user_save_internal(u);
 279 }
 280
 281 int user_load(User *u) {
 282         _cleanup_free_ char *realtime = NULL, *monotonic = NULL, *stopping = NULL;
 283         int r;
 284
 285         assert(u);
 286
 287         r = parse_env_file(NULL, u->state_file, NEWLINE,
 288                            "SERVICE_JOB", &u->service_job,
 289                            "STOPPING",    &stopping,
 290                            "REALTIME",    &realtime,
 291                            "MONOTONIC",   &monotonic,
 292                            NULL);
 293         if (r == -ENOENT)
 294                 return 0;
 295         if (r < 0)
 296                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 297
 298         if (stopping) {
 299                 r = parse_boolean(stopping);
 300                 if (r < 0)
 301                         log_debug_errno(r, "Failed to parse 'STOPPING' boolean: %s", stopping);
 302                 else
 303                         u->stopping = r;
 304         }
 305
 306         if (realtime)
 307                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 308         if (monotonic)
 309                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 310
 311         return 0;
 312 }
 313
 314 static int user_start_service(User *u) {
 315         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 316         char *job;
 317         int r;
 318
 319         assert(u);
 320
 321         u->service_job = mfree(u->service_job);
 322
 323         r = manager_start_unit(
 324                         u->manager,
 325                         u->service,
 326                         &error,
 327                         &job);
 328         if (r < 0)
 329                 /* we don't fail due to this, let's try to continue */
 330                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 331         else
 332                 u->service_job = job;
 333
 334         return 0;
 335 }
 336
 337 int user_start(User *u) {
 338         int r;
 339
 340         assert(u);
 341
 342         if (u->started && !u->stopping)
 343                 return 0;
 344
 345         /*
 346          * If u->stopping is set, the user is marked for removal and the slice
 347          * and service stop-jobs are queued. We have to clear that flag before
 348          * queing the start-jobs again. If they succeed, the user object can be
 349          * re-used just fine (pid1 takes care of job-ordering and proper
 350          * restart), but if they fail, we want to force another user_stop() so
 351          * possibly pending units are stopped.
 352          * Note that we don't clear u->started, as we have no clue what state
 353          * the user is in on failure here. Hence, we pretend the user is
 354          * running so it will be properly taken down by GC. However, we clearly
 355          * return an error from user_start() in that case, so no further
 356          * reference to the user is taken.
 357          */
 358         u->stopping = false;
 359
 360         if (!u->started)
 361                 log_debug("Starting services for new user %s.", u->name);
 362
 363         /* Save the user data so far, because pam_systemd will read the
 364          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 365          * We need to do user_save_internal() because we have not
 366          * "officially" started yet. */
 367         user_save_internal(u);
 368
 369         /* Spawn user systemd */
 370         r = user_start_service(u);
 371         if (r < 0)
 372                 return r;
 373
 374         if (!u->started) {
 375                 if (!dual_timestamp_is_set(&u->timestamp))
 376                         dual_timestamp_get(&u->timestamp);
 377                 user_send_signal(u, true);
 378                 u->started = true;
 379         }
 380
 381         /* Save new user data */
 382         user_save(u);
 383
 384         return 0;
 385 }
 386
 387 static int user_stop_slice(User *u) {
 388         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 389         char *job;
 390         int r;
 391
 392         assert(u);
 393
 394         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 395         if (r < 0)
 396                 return log_error_errno(r, "Failed to stop user slice: %s", bus_error_message(&error, r));
 397
 398         return free_and_replace(u->slice_job, job);
 399 }
 400
 401 static int user_stop_service(User *u) {
 402         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 403         char *job;
 404         int r;
 405
 406         assert(u);
 407
 408         r = manager_stop_unit(u->manager, u->service, &error, &job);
 409         if (r < 0)
 410                 return log_error_errno(r, "Failed to stop user service: %s", bus_error_message(&error, r));
 411
 412         return free_and_replace(u->service_job, job);
 413 }
 414
 415 int user_stop(User *u, bool force) {
 416         Session *s;
 417         int r = 0, k;
 418         assert(u);
 419
 420         /* Stop jobs have already been queued */
 421         if (u->stopping) {
 422                 user_save(u);
 423                 return r;
 424         }
 425
 426         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 427                 k = session_stop(s, force);
 428                 if (k < 0)
 429                         r = k;
 430         }
 431
 432         /* Kill systemd */
 433         k = user_stop_service(u);
 434         if (k < 0)
 435                 r = k;
 436
 437         /* Kill cgroup */
 438         k = user_stop_slice(u);
 439         if (k < 0)
 440                 r = k;
 441
 442         u->stopping = true;
 443
 444         user_save(u);
 445
 446         return r;
 447 }
 448
 449 int user_finalize(User *u) {
 450         Session *s;
 451         int r = 0, k;
 452
 453         assert(u);
 454
 455         if (u->started)
 456                 log_debug("User %s logged out.", u->name);
 457
 458         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 459                 k = session_finalize(s);
 460                 if (k < 0)
 461                         r = k;
 462         }
 463
 464         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 465          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 466          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 467          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 468          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 469          * and do it only for normal users. */
 470         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 471                 k = clean_ipc_by_uid(u->uid);
 472                 if (k < 0)
 473                         r = k;
 474         }
 475
 476         (void) unlink(u->state_file);
 477         user_add_to_gc_queue(u);
 478
 479         if (u->started) {
 480                 user_send_signal(u, false);
 481                 u->started = false;
 482         }
 483
 484         return r;
 485 }
 486
 487 int user_get_idle_hint(User *u, dual_timestamp *t) {
 488         Session *s;
 489         bool idle_hint = true;
 490         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 491
 492         assert(u);
 493
 494         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 495                 dual_timestamp k;
 496                 int ih;
 497
 498                 ih = session_get_idle_hint(s, &k);
 499                 if (ih < 0)
 500                         return ih;
 501
 502                 if (!ih) {
 503                         if (!idle_hint) {
 504                                 if (k.monotonic < ts.monotonic)
 505                                         ts = k;
 506                         } else {
 507                                 idle_hint = false;
 508                                 ts = k;
 509                         }
 510                 } else if (idle_hint) {
 511
 512                         if (k.monotonic > ts.monotonic)
 513                                 ts = k;
 514                 }
 515         }
 516
 517         if (t)
 518                 *t = ts;
 519
 520         return idle_hint;
 521 }
 522
 523 int user_check_linger_file(User *u) {
 524         _cleanup_free_ char *cc = NULL;
 525         char *p = NULL;
 526
 527         cc = cescape(u->name);
 528         if (!cc)
 529                 return -ENOMEM;
 530
 531         p = strjoina("/var/lib/systemd/linger/", cc);
 532
 533         return access(p, F_OK) >= 0;
 534 }
 535
 536 bool user_may_gc(User *u, bool drop_not_started) {
 537         int r;
 538
 539         assert(u);
 540
 541         if (drop_not_started && !u->started)
 542                 return true;
 543
 544         if (u->sessions)
 545                 return false;
 546
 547         if (user_check_linger_file(u) > 0)
 548                 return false;
 549
 550         /* Check if our job is still pending */
 551         if (u->service_job) {
 552                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 553
 554                 r = manager_job_is_active(u->manager, u->service_job, &error);
 555                 if (r < 0)
 556                         log_debug_errno(r, "Failed to determine whether job '%s' is pending, ignoring: %s", u->service_job, bus_error_message(&error, r));
 557                 if (r != 0)
 558                         return false;
 559         }
 560
 561         /* Note that we don't care if the three units we manage for each user object are up or not, as we are managing
 562          * their state rather than tracking it. */
 563
 564         return true;
 565 }
 566
 567 void user_add_to_gc_queue(User *u) {
 568         assert(u);
 569
 570         if (u->in_gc_queue)
 571                 return;
 572
 573         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 574         u->in_gc_queue = true;
 575 }
 576
 577 UserState user_get_state(User *u) {
 578         Session *i;
 579
 580         assert(u);
 581
 582         if (u->stopping)
 583                 return USER_CLOSING;
 584
 585         if (!u->started || u->slice_job || u->service_job)
 586                 return USER_OPENING;
 587
 588         if (u->sessions) {
 589                 bool all_closing = true;
 590
 591                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 592                         SessionState state;
 593
 594                         state = session_get_state(i);
 595                         if (state == SESSION_ACTIVE)
 596                                 return USER_ACTIVE;
 597                         if (state != SESSION_CLOSING)
 598                                 all_closing = false;
 599                 }
 600
 601                 return all_closing ? USER_CLOSING : USER_ONLINE;
 602         }
 603
 604         if (user_check_linger_file(u) > 0)
 605                 return USER_LINGERING;
 606
 607         return USER_CLOSING;
 608 }
 609
 610 int user_kill(User *u, int signo) {
 611         assert(u);
 612
 613         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 614 }
 615
 616 static bool elect_display_filter(Session *s) {
 617         /* Return true if the session is a candidate for the user’s ‘primary session’ or ‘display’. */
 618         assert(s);
 619
 620         return s->class == SESSION_USER && s->started && !s->stopping;
 621 }
 622
 623 static int elect_display_compare(Session *s1, Session *s2) {
 624         /* Indexed by SessionType. Lower numbers mean more preferred. */
 625         const int type_ranks[_SESSION_TYPE_MAX] = {
 626                 [SESSION_UNSPECIFIED] = 0,
 627                 [SESSION_TTY] = -2,
 628                 [SESSION_X11] = -3,
 629                 [SESSION_WAYLAND] = -3,
 630                 [SESSION_MIR] = -3,
 631                 [SESSION_WEB] = -1,
 632         };
 633
 634         /* Calculate the partial order relationship between s1 and s2,
 635          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 636          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 637          * is preferred.
 638          *
 639          * s1 or s2 may be NULL. */
 640         if (!s1 && !s2)
 641                 return 0;
 642
 643         if ((s1 == NULL) != (s2 == NULL))
 644                 return (s1 == NULL) - (s2 == NULL);
 645
 646         if (s1->stopping != s2->stopping)
 647                 return s1->stopping - s2->stopping;
 648
 649         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 650                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 651
 652         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 653                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 654
 655         if (s1->type != s2->type)
 656                 return type_ranks[s1->type] - type_ranks[s2->type];
 657
 658         return 0;
 659 }
 660
 661 void user_elect_display(User *u) {
 662         Session *s;
 663
 664         assert(u);
 665
 666         /* This elects a primary session for each user, which we call the "display". We try to keep the assignment
 667          * stable, but we "upgrade" to better choices. */
 668         log_debug("Electing new display for user %s", u->name);
 669
 670         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 671                 if (!elect_display_filter(s)) {
 672                         log_debug("Ignoring session %s", s->id);
 673                         continue;
 674                 }
 675
 676                 if (elect_display_compare(s, u->display) < 0) {
 677                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 678                         u->display = s;
 679                 }
 680         }
 681 }
 682
 683 static const char* const user_state_table[_USER_STATE_MAX] = {
 684         [USER_OFFLINE] = "offline",
 685         [USER_OPENING] = "opening",
 686         [USER_LINGERING] = "lingering",
 687         [USER_ONLINE] = "online",
 688         [USER_ACTIVE] = "active",
 689         [USER_CLOSING] = "closing"
 690 };
 691
 692 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 693
 694 int config_parse_tmpfs_size(
 695                 const char* unit,
 696                 const char *filename,
 697                 unsigned line,
 698                 const char *section,
 699                 unsigned section_line,
 700                 const char *lvalue,
 701                 int ltype,
 702                 const char *rvalue,
 703                 void *data,
 704                 void *userdata) {
 705
 706         uint64_t *sz = data;
 707         int r;
 708
 709         assert(filename);
 710         assert(lvalue);
 711         assert(rvalue);
 712         assert(data);
 713
 714         /* First, try to parse as percentage */
 715         r = parse_permille(rvalue);
 716         if (r > 0 && r < 1000)
 717                 *sz = physical_memory_scale(r, 1000U);
 718         else {
 719                 uint64_t k;
 720
 721                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 722
 723                 r = parse_size(rvalue, 1024, &k);
 724                 if (r >= 0 && (k <= 0 || (uint64_t) (size_t) k != k))
 725                         r = -ERANGE;
 726                 if (r < 0) {
 727                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value '%s', ignoring: %m", rvalue);
 728                         return 0;
 729                 }
 730
 731                 *sz = PAGE_ALIGN((size_t) k);
 732         }
 733
 734         return 0;
 735 }
 736
 737 int config_parse_compat_user_tasks_max(
 738                 const char *unit,
 739                 const char *filename,
 740                 unsigned line,
 741                 const char *section,
 742                 unsigned section_line,
 743                 const char *lvalue,
 744                 int ltype,
 745                 const char *rvalue,
 746                 void *data,
 747                 void *userdata) {
 748
 749         assert(filename);
 750         assert(lvalue);
 751         assert(rvalue);
 752         assert(data);
 753
 754         log_syntax(unit, LOG_NOTICE, filename, line, 0,
 755                    "Support for option %s= has been removed.",
 756                    lvalue);
 757         log_info("Hint: try creating /etc/systemd/system/user-.slice.d/50-limits.conf with:\n"
 758                  "        [Slice]\n"
 759                  "        TasksMax=%s",
 760                  rvalue);
 761         return 0;
 762 }