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