src/login/logind-user.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2011 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <stdio_ext.h>
  12
  13 #include "alloc-util.h"
  14 #include "bus-common-errors.h"
  15 #include "bus-error.h"
  16 #include "bus-util.h"
  17 #include "cgroup-util.h"
  18 #include "clean-ipc.h"
  19 #include "escape.h"
  20 #include "fd-util.h"
  21 #include "fileio.h"
  22 #include "format-util.h"
  23 #include "fs-util.h"
  24 #include "hashmap.h"
  25 #include "label.h"
  26 #include "logind-user.h"
  27 #include "mkdir.h"
  28 #include "parse-util.h"
  29 #include "path-util.h"
  30 #include "rm-rf.h"
  31 #include "special.h"
  32 #include "stdio-util.h"
  33 #include "string-table.h"
  34 #include "unit-name.h"
  35 #include "user-util.h"
  36 #include "util.h"
  37
  38 int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
  39         _cleanup_(user_freep) User *u = NULL;
  40         char lu[DECIMAL_STR_MAX(uid_t) + 1];
  41         int r;
  42
  43         assert(out);
  44         assert(m);
  45         assert(name);
  46
  47         u = new0(User, 1);
  48         if (!u)
  49                 return -ENOMEM;
  50
  51         u->manager = m;
  52         u->uid = uid;
  53         u->gid = gid;
  54         xsprintf(lu, UID_FMT, uid);
  55
  56         u->name = strdup(name);
  57         if (!u->name)
  58                 return -ENOMEM;
  59
  60         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
  61                 return -ENOMEM;
  62
  63         if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
  64                 return -ENOMEM;
  65
  66         r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
  67         if (r < 0)
  68                 return r;
  69
  70         r = unit_name_build("user", lu, ".service", &u->service);
  71         if (r < 0)
  72                 return r;
  73
  74         r = hashmap_put(m->users, UID_TO_PTR(uid), u);
  75         if (r < 0)
  76                 return r;
  77
  78         r = hashmap_put(m->user_units, u->slice, u);
  79         if (r < 0)
  80                 return r;
  81
  82         r = hashmap_put(m->user_units, u->service, u);
  83         if (r < 0)
  84                 return r;
  85
  86         *out = TAKE_PTR(u);
  87
  88         return 0;
  89 }
  90
  91 User *user_free(User *u) {
  92         if (!u)
  93                 return NULL;
  94
  95         if (u->in_gc_queue)
  96                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
  97
  98         while (u->sessions)
  99                 session_free(u->sessions);
 100
 101         if (u->service)
 102                 hashmap_remove_value(u->manager->user_units, u->service, u);
 103
 104         if (u->slice)
 105                 hashmap_remove_value(u->manager->user_units, u->slice, u);
 106
 107         hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 108
 109         u->slice_job = mfree(u->slice_job);
 110         u->service_job = mfree(u->service_job);
 111
 112         u->service = mfree(u->service);
 113         u->slice = mfree(u->slice);
 114         u->runtime_path = mfree(u->runtime_path);
 115         u->state_file = mfree(u->state_file);
 116         u->name = mfree(u->name);
 117
 118         return mfree(u);
 119 }
 120
 121 static int user_save_internal(User *u) {
 122         _cleanup_free_ char *temp_path = NULL;
 123         _cleanup_fclose_ FILE *f = NULL;
 124         int r;
 125
 126         assert(u);
 127         assert(u->state_file);
 128
 129         r = mkdir_safe_label("/run/systemd/users", 0755, 0, 0, MKDIR_WARN_MODE);
 130         if (r < 0)
 131                 goto fail;
 132
 133         r = fopen_temporary(u->state_file, &f, &temp_path);
 134         if (r < 0)
 135                 goto fail;
 136
 137         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 138         (void) fchmod(fileno(f), 0644);
 139
 140         fprintf(f,
 141                 "# This is private data. Do not parse.\n"
 142                 "NAME=%s\n"
 143                 "STATE=%s\n",
 144                 u->name,
 145                 user_state_to_string(user_get_state(u)));
 146
 147         /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
 148         if (u->runtime_path)
 149                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 150
 151         if (u->service_job)
 152                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 153
 154         if (u->slice_job)
 155                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 156
 157         if (u->display)
 158                 fprintf(f, "DISPLAY=%s\n", u->display->id);
 159
 160         if (dual_timestamp_is_set(&u->timestamp))
 161                 fprintf(f,
 162                         "REALTIME="USEC_FMT"\n"
 163                         "MONOTONIC="USEC_FMT"\n",
 164                         u->timestamp.realtime,
 165                         u->timestamp.monotonic);
 166
 167         if (u->sessions) {
 168                 Session *i;
 169                 bool first;
 170
 171                 fputs("SESSIONS=", f);
 172                 first = true;
 173                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 174                         if (first)
 175                                 first = false;
 176                         else
 177                                 fputc(' ', f);
 178
 179                         fputs(i->id, f);
 180                 }
 181
 182                 fputs("\nSEATS=", f);
 183                 first = true;
 184                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 185                         if (!i->seat)
 186                                 continue;
 187
 188                         if (first)
 189                                 first = false;
 190                         else
 191                                 fputc(' ', f);
 192
 193                         fputs(i->seat->id, f);
 194                 }
 195
 196                 fputs("\nACTIVE_SESSIONS=", f);
 197                 first = true;
 198                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 199                         if (!session_is_active(i))
 200                                 continue;
 201
 202                         if (first)
 203                                 first = false;
 204                         else
 205                                 fputc(' ', f);
 206
 207                         fputs(i->id, f);
 208                 }
 209
 210                 fputs("\nONLINE_SESSIONS=", f);
 211                 first = true;
 212                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 213                         if (session_get_state(i) == SESSION_CLOSING)
 214                                 continue;
 215
 216                         if (first)
 217                                 first = false;
 218                         else
 219                                 fputc(' ', f);
 220
 221                         fputs(i->id, f);
 222                 }
 223
 224                 fputs("\nACTIVE_SEATS=", f);
 225                 first = true;
 226                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 227                         if (!session_is_active(i) || !i->seat)
 228                                 continue;
 229
 230                         if (first)
 231                                 first = false;
 232                         else
 233                                 fputc(' ', f);
 234
 235                         fputs(i->seat->id, f);
 236                 }
 237
 238                 fputs("\nONLINE_SEATS=", f);
 239                 first = true;
 240                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 241                         if (session_get_state(i) == SESSION_CLOSING || !i->seat)
 242                                 continue;
 243
 244                         if (first)
 245                                 first = false;
 246                         else
 247                                 fputc(' ', f);
 248
 249                         fputs(i->seat->id, f);
 250                 }
 251                 fputc('\n', f);
 252         }
 253
 254         r = fflush_and_check(f);
 255         if (r < 0)
 256                 goto fail;
 257
 258         if (rename(temp_path, u->state_file) < 0) {
 259                 r = -errno;
 260                 goto fail;
 261         }
 262
 263         return 0;
 264
 265 fail:
 266         (void) unlink(u->state_file);
 267
 268         if (temp_path)
 269                 (void) unlink(temp_path);
 270
 271         return log_error_errno(r, "Failed to save user data %s: %m", u->state_file);
 272 }
 273
 274 int user_save(User *u) {
 275         assert(u);
 276
 277         if (!u->started)
 278                 return 0;
 279
 280         return user_save_internal (u);
 281 }
 282
 283 int user_load(User *u) {
 284         _cleanup_free_ char *display = NULL, *realtime = NULL, *monotonic = NULL;
 285         Session *s = NULL;
 286         int r;
 287
 288         assert(u);
 289
 290         r = parse_env_file(u->state_file, NEWLINE,
 291                            "SERVICE_JOB", &u->service_job,
 292                            "SLICE_JOB",   &u->slice_job,
 293                            "DISPLAY",     &display,
 294                            "REALTIME",    &realtime,
 295                            "MONOTONIC",   &monotonic,
 296                            NULL);
 297         if (r < 0) {
 298                 if (r == -ENOENT)
 299                         return 0;
 300
 301                 return log_error_errno(r, "Failed to read %s: %m", u->state_file);
 302         }
 303
 304         if (display)
 305                 s = hashmap_get(u->manager->sessions, display);
 306
 307         if (s && s->display && display_is_local(s->display))
 308                 u->display = s;
 309
 310         if (realtime)
 311                 timestamp_deserialize(realtime, &u->timestamp.realtime);
 312         if (monotonic)
 313                 timestamp_deserialize(monotonic, &u->timestamp.monotonic);
 314
 315         return r;
 316 }
 317
 318 static int user_start_service(User *u) {
 319         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 320         char *job;
 321         int r;
 322
 323         assert(u);
 324
 325         u->service_job = mfree(u->service_job);
 326
 327         r = manager_start_unit(
 328                         u->manager,
 329                         u->service,
 330                         &error,
 331                         &job);
 332         if (r < 0)
 333                 /* we don't fail due to this, let's try to continue */
 334                 log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
 335         else
 336                 u->service_job = job;
 337
 338         return 0;
 339 }
 340
 341 int user_start(User *u) {
 342         int r;
 343
 344         assert(u);
 345
 346         if (u->started && !u->stopping)
 347                 return 0;
 348
 349         /*
 350          * If u->stopping is set, the user is marked for removal and the slice
 351          * and service stop-jobs are queued. We have to clear that flag before
 352          * queing the start-jobs again. If they succeed, the user object can be
 353          * re-used just fine (pid1 takes care of job-ordering and proper
 354          * restart), but if they fail, we want to force another user_stop() so
 355          * possibly pending units are stopped.
 356          * Note that we don't clear u->started, as we have no clue what state
 357          * the user is in on failure here. Hence, we pretend the user is
 358          * running so it will be properly taken down by GC. However, we clearly
 359          * return an error from user_start() in that case, so no further
 360          * reference to the user is taken.
 361          */
 362         u->stopping = false;
 363
 364         if (!u->started)
 365                 log_debug("Starting services for new user %s.", u->name);
 366
 367         /* Save the user data so far, because pam_systemd will read the
 368          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
 369          * We need to do user_save_internal() because we have not
 370          * "officially" started yet. */
 371         user_save_internal(u);
 372
 373         /* Spawn user systemd */
 374         r = user_start_service(u);
 375         if (r < 0)
 376                 return r;
 377
 378         if (!u->started) {
 379                 if (!dual_timestamp_is_set(&u->timestamp))
 380                         dual_timestamp_get(&u->timestamp);
 381                 user_send_signal(u, true);
 382                 u->started = true;
 383         }
 384
 385         /* Save new user data */
 386         user_save(u);
 387
 388         return 0;
 389 }
 390
 391 static int user_stop_slice(User *u) {
 392         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 393         char *job;
 394         int r;
 395
 396         assert(u);
 397
 398         r = manager_stop_unit(u->manager, u->slice, &error, &job);
 399         if (r < 0) {
 400                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
 401                 return r;
 402         }
 403
 404         free(u->slice_job);
 405         u->slice_job = job;
 406
 407         return r;
 408 }
 409
 410 static int user_stop_service(User *u) {
 411         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 412         char *job;
 413         int r;
 414
 415         assert(u);
 416
 417         r = manager_stop_unit(u->manager, u->service, &error, &job);
 418         if (r < 0) {
 419                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
 420                 return r;
 421         }
 422
 423         free_and_replace(u->service_job, job);
 424         return r;
 425 }
 426
 427 int user_stop(User *u, bool force) {
 428         Session *s;
 429         int r = 0, k;
 430         assert(u);
 431
 432         /* Stop jobs have already been queued */
 433         if (u->stopping) {
 434                 user_save(u);
 435                 return r;
 436         }
 437
 438         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 439                 k = session_stop(s, force);
 440                 if (k < 0)
 441                         r = k;
 442         }
 443
 444         /* Kill systemd */
 445         k = user_stop_service(u);
 446         if (k < 0)
 447                 r = k;
 448
 449         /* Kill cgroup */
 450         k = user_stop_slice(u);
 451         if (k < 0)
 452                 r = k;
 453
 454         u->stopping = true;
 455
 456         user_save(u);
 457
 458         return r;
 459 }
 460
 461 int user_finalize(User *u) {
 462         Session *s;
 463         int r = 0, k;
 464
 465         assert(u);
 466
 467         if (u->started)
 468                 log_debug("User %s logged out.", u->name);
 469
 470         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 471                 k = session_finalize(s);
 472                 if (k < 0)
 473                         r = k;
 474         }
 475
 476         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
 477          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
 478          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
 479          * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
 480          * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
 481          * and do it only for normal users. */
 482         if (u->manager->remove_ipc && !uid_is_system(u->uid)) {
 483                 k = clean_ipc_by_uid(u->uid);
 484                 if (k < 0)
 485                         r = k;
 486         }
 487
 488         unlink(u->state_file);
 489         user_add_to_gc_queue(u);
 490
 491         if (u->started) {
 492                 user_send_signal(u, false);
 493                 u->started = false;
 494         }
 495
 496         return r;
 497 }
 498
 499 int user_get_idle_hint(User *u, dual_timestamp *t) {
 500         Session *s;
 501         bool idle_hint = true;
 502         dual_timestamp ts = DUAL_TIMESTAMP_NULL;
 503
 504         assert(u);
 505
 506         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 507                 dual_timestamp k;
 508                 int ih;
 509
 510                 ih = session_get_idle_hint(s, &k);
 511                 if (ih < 0)
 512                         return ih;
 513
 514                 if (!ih) {
 515                         if (!idle_hint) {
 516                                 if (k.monotonic < ts.monotonic)
 517                                         ts = k;
 518                         } else {
 519                                 idle_hint = false;
 520                                 ts = k;
 521                         }
 522                 } else if (idle_hint) {
 523
 524                         if (k.monotonic > ts.monotonic)
 525                                 ts = k;
 526                 }
 527         }
 528
 529         if (t)
 530                 *t = ts;
 531
 532         return idle_hint;
 533 }
 534
 535 int user_check_linger_file(User *u) {
 536         _cleanup_free_ char *cc = NULL;
 537         char *p = NULL;
 538
 539         cc = cescape(u->name);
 540         if (!cc)
 541                 return -ENOMEM;
 542
 543         p = strjoina("/var/lib/systemd/linger/", cc);
 544
 545         return access(p, F_OK) >= 0;
 546 }
 547
 548 bool user_may_gc(User *u, bool drop_not_started) {
 549         assert(u);
 550
 551         if (drop_not_started && !u->started)
 552                 return true;
 553
 554         if (u->sessions)
 555                 return false;
 556
 557         if (user_check_linger_file(u) > 0)
 558                 return false;
 559
 560         if (u->slice_job && manager_job_is_active(u->manager, u->slice_job))
 561                 return false;
 562
 563         if (u->service_job && manager_job_is_active(u->manager, u->service_job))
 564                 return false;
 565
 566         return true;
 567 }
 568
 569 void user_add_to_gc_queue(User *u) {
 570         assert(u);
 571
 572         if (u->in_gc_queue)
 573                 return;
 574
 575         LIST_PREPEND(gc_queue, u->manager->user_gc_queue, u);
 576         u->in_gc_queue = true;
 577 }
 578
 579 UserState user_get_state(User *u) {
 580         Session *i;
 581
 582         assert(u);
 583
 584         if (u->stopping)
 585                 return USER_CLOSING;
 586
 587         if (!u->started || u->slice_job || u->service_job)
 588                 return USER_OPENING;
 589
 590         if (u->sessions) {
 591                 bool all_closing = true;
 592
 593                 LIST_FOREACH(sessions_by_user, i, u->sessions) {
 594                         SessionState state;
 595
 596                         state = session_get_state(i);
 597                         if (state == SESSION_ACTIVE)
 598                                 return USER_ACTIVE;
 599                         if (state != SESSION_CLOSING)
 600                                 all_closing = false;
 601                 }
 602
 603                 return all_closing ? USER_CLOSING : USER_ONLINE;
 604         }
 605
 606         if (user_check_linger_file(u) > 0)
 607                 return USER_LINGERING;
 608
 609         return USER_CLOSING;
 610 }
 611
 612 int user_kill(User *u, int signo) {
 613         assert(u);
 614
 615         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 616 }
 617
 618 static bool elect_display_filter(Session *s) {
 619         /* Return true if the session is a candidate for the user’s ‘primary
 620          * session’ or ‘display’. */
 621         assert(s);
 622
 623         return (s->class == SESSION_USER && !s->stopping);
 624 }
 625
 626 static int elect_display_compare(Session *s1, Session *s2) {
 627         /* Indexed by SessionType. Lower numbers mean more preferred. */
 628         const int type_ranks[_SESSION_TYPE_MAX] = {
 629                 [SESSION_UNSPECIFIED] = 0,
 630                 [SESSION_TTY] = -2,
 631                 [SESSION_X11] = -3,
 632                 [SESSION_WAYLAND] = -3,
 633                 [SESSION_MIR] = -3,
 634                 [SESSION_WEB] = -1,
 635         };
 636
 637         /* Calculate the partial order relationship between s1 and s2,
 638          * returning < 0 if s1 is preferred as the user’s ‘primary session’,
 639          * 0 if s1 and s2 are equally preferred or incomparable, or > 0 if s2
 640          * is preferred.
 641          *
 642          * s1 or s2 may be NULL. */
 643         if (!s1 && !s2)
 644                 return 0;
 645
 646         if ((s1 == NULL) != (s2 == NULL))
 647                 return (s1 == NULL) - (s2 == NULL);
 648
 649         if (s1->stopping != s2->stopping)
 650                 return s1->stopping - s2->stopping;
 651
 652         if ((s1->class != SESSION_USER) != (s2->class != SESSION_USER))
 653                 return (s1->class != SESSION_USER) - (s2->class != SESSION_USER);
 654
 655         if ((s1->type == _SESSION_TYPE_INVALID) != (s2->type == _SESSION_TYPE_INVALID))
 656                 return (s1->type == _SESSION_TYPE_INVALID) - (s2->type == _SESSION_TYPE_INVALID);
 657
 658         if (s1->type != s2->type)
 659                 return type_ranks[s1->type] - type_ranks[s2->type];
 660
 661         return 0;
 662 }
 663
 664 void user_elect_display(User *u) {
 665         Session *s;
 666
 667         assert(u);
 668
 669         /* This elects a primary session for each user, which we call
 670          * the "display". We try to keep the assignment stable, but we
 671          * "upgrade" to better choices. */
 672         log_debug("Electing new display for user %s", u->name);
 673
 674         LIST_FOREACH(sessions_by_user, s, u->sessions) {
 675                 if (!elect_display_filter(s)) {
 676                         log_debug("Ignoring session %s", s->id);
 677                         continue;
 678                 }
 679
 680                 if (elect_display_compare(s, u->display) < 0) {
 681                         log_debug("Choosing session %s in preference to %s", s->id, u->display ? u->display->id : "-");
 682                         u->display = s;
 683                 }
 684         }
 685 }
 686
 687 static const char* const user_state_table[_USER_STATE_MAX] = {
 688         [USER_OFFLINE] = "offline",
 689         [USER_OPENING] = "opening",
 690         [USER_LINGERING] = "lingering",
 691         [USER_ONLINE] = "online",
 692         [USER_ACTIVE] = "active",
 693         [USER_CLOSING] = "closing"
 694 };
 695
 696 DEFINE_STRING_TABLE_LOOKUP(user_state, UserState);
 697
 698 int config_parse_tmpfs_size(
 699                 const char* unit,
 700                 const char *filename,
 701                 unsigned line,
 702                 const char *section,
 703                 unsigned section_line,
 704                 const char *lvalue,
 705                 int ltype,
 706                 const char *rvalue,
 707                 void *data,
 708                 void *userdata) {
 709
 710         size_t *sz = data;
 711         int r;
 712
 713         assert(filename);
 714         assert(lvalue);
 715         assert(rvalue);
 716         assert(data);
 717
 718         /* First, try to parse as percentage */
 719         r = parse_percent(rvalue);
 720         if (r > 0 && r < 100)
 721                 *sz = physical_memory_scale(r, 100U);
 722         else {
 723                 uint64_t k;
 724
 725                 /* If the passed argument was not a percentage, or out of range, parse as byte size */
 726
 727                 r = parse_size(rvalue, 1024, &k);
 728                 if (r < 0 || k <= 0 || (uint64_t) (size_t) k != k) {
 729                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse size value, ignoring: %s", rvalue);
 730                         return 0;
 731                 }
 732
 733                 *sz = PAGE_ALIGN((size_t) k);
 734         }
 735
 736         return 0;
 737 }
 738
 739 int config_parse_compat_user_tasks_max(
 740                 const char *unit,
 741                 const char *filename,
 742                 unsigned line,
 743                 const char *section,
 744                 unsigned section_line,
 745                 const char *lvalue,
 746                 int ltype,
 747                 const char *rvalue,
 748                 void *data,
 749                 void *userdata) {
 750
 751         assert(filename);
 752         assert(lvalue);
 753         assert(rvalue);
 754         assert(data);
 755
 756         log_syntax(unit, LOG_NOTICE, filename, line, 0,
 757                    "Support for option %s= has been removed.",
 758                    lvalue);
 759         log_info("Hint: try creating /etc/systemd/system/user-.slice/50-limits.conf with:\n"
 760                  "        [Slice]\n"
 761                  "        TasksMax=%s",
 762                  rvalue);
 763         return 0;
 764 }