src/login/logind-user.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2011 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <stdio_ext.h>
  10
  11 #include "alloc-util.h"
  12 #include "bus-common-errors.h"
  13 #include "bus-error.h"
  14 #include "bus-util.h"
  15 #include "cgroup-util.h"
  16 #include "clean-ipc.h"
  17 #include "escape.h"
  18 #include "fd-util.h"
  19 #include "fileio.h"
  20 #include "format-util.h"
  21 #include "fs-util.h"
  22 #include "hashmap.h"
  23 #include "label.h"
  24 #include "logind-user.h"
  25 #include "mkdir.h"
  26 #include "parse-util.h"
  27 #include "path-util.h"
  28 #include "rm-rf.h"
  29 #include "special.h"
  30 #include "stdio-util.h"
  31 #include "string-table.h"
  32 #include "unit-name.h"
  33 #include "user-util.h"
  34 #include "util.h"
  35
  36 int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
  37         _cleanup_(user_freep) User *u = NULL;
  38         char lu[DECIMAL_STR_MAX(uid_t) + 1];
  39         int r;
  40
  41         assert(out);
  42         assert(m);
  43         assert(name);
  44
  45         u = new0(User, 1);
  46         if (!u)
  47                 return -ENOMEM;
  48
  49         u->manager = m;
  50         u->uid = uid;
  51         u->gid = gid;
  52         xsprintf(lu, UID_FMT, uid);
  53
  54         u->name = strdup(name);
  55         if (!u->name)
  56                 return -ENOMEM;
  57
  58         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  59                 return -ENOMEM;
  60
  61         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  62                 return -ENOMEM;
  63
  64         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  65         if (r < 0)
  66                 return r;
  67
  68         r = unit_name_build("user", lu, ".service", &u->service);
  69         if (r < 0)
  70                 return r;
  71
  72         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  73         if (r < 0)
  74                 return r;
  75
  76         r = hashmap_put(m->user_units, u->slice, u);
  77         if (r < 0)
  78                 return r;
  79
  80         r = hashmap_put(m->user_units, u->service, u);
  81         if (r < 0)
  82                 return r;
  83
  84         *out = TAKE_PTR(u);
  85
  86         return 0;
  87 }
  88
  89 User *user_free(User *u) {
  90         if (!u)
  91                 return NULL;
  92
  93         if (u->in_gc_queue)
  94                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
  95
  96         while (u->sessions)
  97                 session_free(u->sessions);
  98
  99         if (u->service)
 100                 hashmap_remove_value(u->manager->user_units, u->service, u);
 101
 102         if (u->slice)
 103                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 104
 105         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 106
 107         u->slice_job = mfree(u->slice_job);
 108         u->service_job = mfree(u->service_job);
 109
 110         u->service = mfree(u->service);
 111         u->slice = mfree(u->slice);
 112         u->runtime_path = mfree(u->runtime_path);
 113         u->state_file = mfree(u->state_file);
 114         u->name = mfree(u->name);
 115
 116         return mfree(u);
 117 }
 118
 119 static int user_save_internal(User *u) {
 120         _cleanup_free_ char *temp_path = NULL;
 121         _cleanup_fclose_ FILE *f = NULL;
 122         int r;
 123
 124         assert(u);
 125         assert(u->state_file);
 126
 127         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
 128         if (r < 0)
 129                 goto fail;
 130
 131         r = fopen_temporary(u->state_file, &f, &temp_path);
 132         if (r < 0)
 133                 goto fail;
 134
 135         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 136         (void) fchmod(fileno(f), 0644);
 137
 138         fprintf(f,
 139                 "# This is private data. Do not parse.\n"
 140                 "NAME=%s\n"
 141                 "STATE=%s\n",
 142                 u->name,
 143                 user_state_to_string(user_get_state(u)));
 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 *display = NULL, *realtime = NULL, *monotonic = NULL;
 283         Session *s = NULL;
 284         int r;
 285
 286         assert(u);
 287
 288         r = parse_env_file(NULL, u->state_file, NEWLINE,
 289                            "SERVICE_JOB", &u->service_job,
 290                            "SLICE_JOB",   &u->slice_job,
 291                            "DISPLAY",     &display,
 292                            "REALTIME",    &realtime,
 293                            "MONOTONIC",   &monotonic,
 294                            NULL);
 295         if (r < 0) {
 296                 if (r == -ENOENT)
 297                         return 0;
 298
 299                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 300         }
 301
 302         if (display)
 303                 s = hashmap_get(u->manager->sessions, display);
 304
 305         if (s && s->display && display_is_local(s->display))
 306                 u->display = s;
 307
 308         if (realtime)
 309                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 310         if (monotonic)
 311                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 312
 313         return r;
 314 }
 315
 316 static int user_start_service(User *u) {
 317         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 318         char *job;
 319         int r;
 320
 321         assert(u);
 322
 323         u->service_job = mfree(u->service_job);
 324
 325         r = manager_start_unit(
 326                         u->manager,
 327                         u->service,
 328                         &error,
 329                         &job);
 330         if (r < 0)
 331                 /* we don't fail due to this, let's try to continue */
 332                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 333         else
 334                 u->service_job = job;
 335
 336         return 0;
 337 }
 338
 339 int user_start(User *u) {
 340         int r;
 341
 342         assert(u);
 343
 344         if (u->started && !u->stopping)
 345                 return 0;
 346
 347         /*
 348          * If u->stopping is set, the user is marked for removal and the slice
 349          * and service stop-jobs are queued. We have to clear that flag before
 350          * queing the start-jobs again. If they succeed, the user object can be
 351          * re-used just fine (pid1 takes care of job-ordering and proper
 352          * restart), but if they fail, we want to force another user_stop() so
 353          * possibly pending units are stopped.
 354          * Note that we don't clear u->started, as we have no clue what state
 355          * the user is in on failure here. Hence, we pretend the user is
 356          * running so it will be properly taken down by GC. However, we clearly
 357          * return an error from user_start() in that case, so no further
 358          * reference to the user is taken.
 359          */
 360         u->stopping = false;
 361
 362         if (!u->started)
 363                 log_debug("Starting services for new user %s.", u->name);
 364
 365         /* Save the user data so far, because pam_systemd will read the
 366          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 367          * We need to do user_save_internal() because we have not
 368          * "officially" started yet. */
 369         user_save_internal(u);
 370
 371         /* Spawn user systemd */
 372         r = user_start_service(u);
 373         if (r < 0)
 374                 return r;
 375
 376         if (!u->started) {
 377                 if (!dual_timestamp_is_set(&u->timestamp))
 378                         dual_timestamp_get(&u->timestamp);
 379                 user_send_signal(u, true);
 380                 u->started = true;
 381         }
 382
 383         /* Save new user data */
 384         user_save(u);
 385
 386         return 0;
 387 }
 388
 389 static int user_stop_slice(User *u) {
 390         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 391         char *job;
 392         int r;
 393
 394         assert(u);
 395
 396         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 397         if (r < 0) {
 398                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 399                 return r;
 400         }
 401
 402         free(u->slice_job);
 403         u->slice_job = job;
 404
 405         return r;
 406 }
 407
 408 static int user_stop_service(User *u) {
 409         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 410         char *job;
 411         int r;
 412
 413         assert(u);
 414
 415         r = manager_stop_unit(u->manager, u->service, &error, &job);
 416         if (r < 0) {
 417                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 418                 return r;
 419         }
 420
 421         free_and_replace(u->service_job, job);
 422         return r;
 423 }
 424
 425 int user_stop(User *u, bool force) {
 426         Session *s;
 427         int r = 0, k;
 428         assert(u);
 429
 430         /* Stop jobs have already been queued */
 431         if (u->stopping) {
 432                 user_save(u);
 433                 return r;
 434         }
 435
 436         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 437                 k = session_stop(s, force);
 438                 if (k < 0)
 439                         r = k;
 440         }
 441
 442         /* Kill systemd */
 443         k = user_stop_service(u);
 444         if (k < 0)
 445                 r = k;
 446
 447         /* Kill cgroup */
 448         k = user_stop_slice(u);
 449         if (k < 0)
 450                 r = k;
 451
 452         u->stopping = true;
 453
 454         user_save(u);
 455
 456         return r;
 457 }
 458
 459 int user_finalize(User *u) {
 460         Session *s;
 461         int r = 0, k;
 462
 463         assert(u);
 464
 465         if (u->started)
 466                 log_debug("User %s logged out.", u->name);
 467
 468         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 469                 k = session_finalize(s);
 470                 if (k < 0)
 471                         r = k;
 472         }
 473
 474         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 475          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 476          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 477          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 478          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 479          * and do it only for normal users. */
 480         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 481                 k = clean_ipc_by_uid(u->uid);
 482                 if (k < 0)
 483                         r = k;
 484         }
 485
 486         unlink(u->state_file);
 487         user_add_to_gc_queue(u);
 488
 489         if (u->started) {
 490                 user_send_signal(u, false);
 491                 u->started = false;
 492         }
 493
 494         return r;
 495 }
 496
 497 int user_get_idle_hint(User *u, dual_timestamp *t) {
 498         Session *s;
 499         bool idle_hint = true;
 500         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 501
 502         assert(u);
 503
 504         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 505                 dual_timestamp k;
 506                 int ih;
 507
 508                 ih = session_get_idle_hint(s, &k);
 509                 if (ih < 0)
 510                         return ih;
 511
 512                 if (!ih) {
 513                         if (!idle_hint) {
 514                                 if (k.monotonic < ts.monotonic)
 515                                         ts = k;
 516                         } else {
 517                                 idle_hint = false;
 518                                 ts = k;
 519                         }
 520                 } else if (idle_hint) {
 521
 522                         if (k.monotonic > ts.monotonic)
 523                                 ts = k;
 524                 }
 525         }
 526
 527         if (t)
 528                 *t = ts;
 529
 530         return idle_hint;
 531 }
 532
 533 int user_check_linger_file(User *u) {
 534         _cleanup_free_ char *cc = NULL;
 535         char *p = NULL;
 536
 537         cc = cescape(u->name);
 538         if (!cc)
 539                 return -ENOMEM;
 540
 541         p = strjoina("/var/lib/systemd/linger/", cc);
 542
 543         return access(p, F_OK) >= 0;
 544 }
 545
 546 bool user_may_gc(User *u, bool drop_not_started) {
 547         assert(u);
 548
 549         if (drop_not_started && !u->started)
 550                 return true;
 551
 552         if (u->sessions)
 553                 return false;
 554
 555         if (user_check_linger_file(u) > 0)
 556                 return false;
 557
 558         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 559                 return false;
 560
 561         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 562                 return false;
 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
 618          * session’ or ‘display’. */
 619         assert(s);
 620
 621         return (s->class == SESSION_USER && !s->stopping);
 622 }
 623
 624 static int elect_display_compare(Session *s1, Session *s2) {
 625         /* Indexed by SessionType. Lower numbers mean more preferred. */
 626         const int type_ranks[_SESSION_TYPE_MAX] = {
 627                 [SESSION_UNSPECIFIED] = 0,
 628                 [SESSION_TTY] = -2,
 629                 [SESSION_X11] = -3,
 630                 [SESSION_WAYLAND] = -3,
 631                 [SESSION_MIR] = -3,
 632                 [SESSION_WEB] = -1,
 633         };
 634
 635         /* Calculate the partial order relationship between s1 and s2,
 636          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 637          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 638          * is preferred.
 639          *
 640          * s1 or s2 may be NULL. */
 641         if (!s1 && !s2)
 642                 return 0;
 643
 644         if ((s1 == NULL) != (s2 == NULL))
 645                 return (s1 == NULL) - (s2 == NULL);
 646
 647         if (s1->stopping != s2->stopping)
 648                 return s1->stopping - s2->stopping;
 649
 650         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 651                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 652
 653         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 654                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 655
 656         if (s1->type != s2->type)
 657                 return type_ranks[s1->type] - type_ranks[s2->type];
 658
 659         return 0;
 660 }
 661
 662 void user_elect_display(User *u) {
 663         Session *s;
 664
 665         assert(u);
 666
 667         /* This elects a primary session for each user, which we call
 668          * the "display". We try to keep the assignment stable, but we
 669          * "upgrade" to better choices. */
 670         log_debug("Electing new display for user %s", u->name);
 671
 672         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 673                 if (!elect_display_filter(s)) {
 674                         log_debug("Ignoring session %s", s->id);
 675                         continue;
 676                 }
 677
 678                 if (elect_display_compare(s, u->display) < 0) {
 679                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 680                         u->display = s;
 681                 }
 682         }
 683 }
 684
 685 static const char* const user_state_table[_USER_STATE_MAX] = {
 686         [USER_OFFLINE] = "offline",
 687         [USER_OPENING] = "opening",
 688         [USER_LINGERING] = "lingering",
 689         [USER_ONLINE] = "online",
 690         [USER_ACTIVE] = "active",
 691         [USER_CLOSING] = "closing"
 692 };
 693
 694 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 695
 696 int config_parse_tmpfs_size(
 697                 const char* unit,
 698                 const char *filename,
 699                 unsigned line,
 700                 const char *section,
 701                 unsigned section_line,
 702                 const char *lvalue,
 703                 int ltype,
 704                 const char *rvalue,
 705                 void *data,
 706                 void *userdata) {
 707
 708         uint64_t *sz = data;
 709         int r;
 710
 711         assert(filename);
 712         assert(lvalue);
 713         assert(rvalue);
 714         assert(data);
 715
 716         /* First, try to parse as percentage */
 717         r = parse_percent(rvalue);
 718         if (r > 0 && r < 100)
 719                 *sz = physical_memory_scale(r, 100U);
 720         else {
 721                 uint64_t k;
 722
 723                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 724
 725                 r = parse_size(rvalue, 1024, &k);
 726                 if (r < 0 || k <= 0 || (uint64_t) (size_t) k != k) {
 727                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value, ignoring: %s", 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/50-limits.conf with:\n"
 758                  "        [Slice]\n"
 759                  "        TasksMax=%s",
 760                  rvalue);
 761         return 0;
 762 }