summaryrefslogtreecommitdiff
path: root/src/libsystemd/sd-login/sd-login.c
blob: 3f2e459825797b4f2f124e924de63a69b265119e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2011 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <poll.h>
#include <string.h>
#include <sys/inotify.h>
#include <unistd.h>

#include "sd-login.h"

#include "alloc-util.h"
#include "cgroup-util.h"
#include "dirent-util.h"
#include "escape.h"
#include "fd-util.h"
#include "fileio.h"
#include "formats-util.h"
#include "fs-util.h"
#include "hostname-util.h"
#include "io-util.h"
#include "login-util.h"
#include "macro.h"
#include "parse-util.h"
#include "path-util.h"
#include "socket-util.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"
#include "util.h"

/* Error codes:
 *
 *    invalid input parameters                → -EINVAL
 *    invalid fd                              → -EBADF
 *    process does not exist                  → -ESRCH
 *    cgroup does not exist                   → -ENOENT
 *    machine, session does not exist         → -ENXIO
 *    requested metadata on object is missing → -ENODATA
 */

_public_ int sd_pid_get_session(pid_t pid, char **session) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(session, -EINVAL);

        return cg_pid_get_session(pid, session);
}

_public_ int sd_pid_get_unit(pid_t pid, char **unit) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(unit, -EINVAL);

        return cg_pid_get_unit(pid, unit);
}

_public_ int sd_pid_get_user_unit(pid_t pid, char **unit) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(unit, -EINVAL);

        return cg_pid_get_user_unit(pid, unit);
}

_public_ int sd_pid_get_machine_name(pid_t pid, char **name) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(name, -EINVAL);

        return cg_pid_get_machine_name(pid, name);
}

_public_ int sd_pid_get_slice(pid_t pid, char **slice) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(slice, -EINVAL);

        return cg_pid_get_slice(pid, slice);
}

_public_ int sd_pid_get_user_slice(pid_t pid, char **slice) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(slice, -EINVAL);

        return cg_pid_get_user_slice(pid, slice);
}

_public_ int sd_pid_get_owner_uid(pid_t pid, uid_t *uid) {

        assert_return(pid >= 0, -EINVAL);
        assert_return(uid, -EINVAL);

        return cg_pid_get_owner_uid(pid, uid);
}

_public_ int sd_pid_get_cgroup(pid_t pid, char **cgroup) {
        char *c;
        int r;

        assert_return(pid >= 0, -EINVAL);
        assert_return(cgroup, -EINVAL);

        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &c);
        if (r < 0)
                return r;

        /* The internal APIs return the empty string for the root
         * cgroup, let's return the "/" in the public APIs instead, as
         * that's easier and less ambigious for people to grok. */
        if (isempty(c)) {
                free(c);
                c = strdup("/");
                if (!c)
                        return -ENOMEM;

        }

        *cgroup = c;
        return 0;
}

_public_ int sd_peer_get_session(int fd, char **session) {
        struct ucred ucred = {};
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(session, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_session(ucred.pid, session);
}

_public_ int sd_peer_get_owner_uid(int fd, uid_t *uid) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(uid, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_owner_uid(ucred.pid, uid);
}

_public_ int sd_peer_get_unit(int fd, char **unit) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(unit, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_unit(ucred.pid, unit);
}

_public_ int sd_peer_get_user_unit(int fd, char **unit) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(unit, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_user_unit(ucred.pid, unit);
}

_public_ int sd_peer_get_machine_name(int fd, char **machine) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(machine, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_machine_name(ucred.pid, machine);
}

_public_ int sd_peer_get_slice(int fd, char **slice) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(slice, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_slice(ucred.pid, slice);
}

_public_ int sd_peer_get_user_slice(int fd, char **slice) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(slice, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return cg_pid_get_user_slice(ucred.pid, slice);
}

_public_ int sd_peer_get_cgroup(int fd, char **cgroup) {
        struct ucred ucred;
        int r;

        assert_return(fd >= 0, -EBADF);
        assert_return(cgroup, -EINVAL);

        r = getpeercred(fd, &ucred);
        if (r < 0)
                return r;

        return sd_pid_get_cgroup(ucred.pid, cgroup);
}

static int file_of_uid(uid_t uid, char **p) {

        assert_return(uid_is_valid(uid), -EINVAL);
        assert(p);

        if (asprintf(p, "/run/systemd/users/" UID_FMT, uid) < 0)
                return -ENOMEM;

        return 0;
}

_public_ int sd_uid_get_state(uid_t uid, char**state) {
        _cleanup_free_ char *p = NULL;
        char *s = NULL;
        int r;

        assert_return(state, -EINVAL);

        r = file_of_uid(uid, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "STATE", &s, NULL);
        if (r == -ENOENT) {
                free(s);
                s = strdup("offline");
                if (!s)
                        return -ENOMEM;

        }
        if (r < 0) {
                free(s);
                return r;
        }
        if (isempty(s)) {
                free(s);
                return -EIO;
        }

        *state = s;
        return 0;
}

_public_ int sd_uid_get_display(uid_t uid, char **session) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        assert_return(session, -EINVAL);

        r = file_of_uid(uid, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "DISPLAY", &s, NULL);
        if (r == -ENOENT)
                return -ENODATA;
        if (r < 0)
                return r;
        if (isempty(s))
                return -ENODATA;

        *session = s;
        s = NULL;

        return 0;
}

static int file_of_seat(const char *seat, char **_p) {
        char *p;
        int r;

        assert(_p);

        if (seat) {
                if (!filename_is_valid(seat))
                        return -EINVAL;

                p = strappend("/run/systemd/seats/", seat);
        } else {
                _cleanup_free_ char *buf = NULL;

                r = sd_session_get_seat(NULL, &buf);
                if (r < 0)
                        return r;

                p = strappend("/run/systemd/seats/", buf);
        }

        if (!p)
                return -ENOMEM;

        *_p = p;
        p = NULL;
        return 0;
}

_public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) {
        _cleanup_free_ char *t = NULL, *s = NULL, *p = NULL;
        size_t l;
        int r;
        const char *word, *variable, *state;

        assert_return(uid_is_valid(uid), -EINVAL);

        r = file_of_seat(seat, &p);
        if (r < 0)
                return r;

        variable = require_active ? "ACTIVE_UID" : "UIDS";

        r = parse_env_file(p, NEWLINE, variable, &s, NULL);
        if (r == -ENOENT)
                return 0;
        if (r < 0)
                return r;
        if (isempty(s))
                return 0;

        if (asprintf(&t, UID_FMT, uid) < 0)
                return -ENOMEM;

        FOREACH_WORD(word, l, s, state)
                if (strneq(t, word, l))
                        return 1;

        return 0;
}

static int uid_get_array(uid_t uid, const char *variable, char ***array) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        char **a;
        int r;

        assert(variable);

        r = file_of_uid(uid, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, variable, &s, NULL);
        if (r == -ENOENT || (r >= 0 && isempty(s))) {
                if (array)
                        *array = NULL;
                return 0;
        }
        if (r < 0)
                return r;

        a = strv_split(s, " ");
        if (!a)
                return -ENOMEM;

        strv_uniq(a);
        r = strv_length(a);

        if (array)
                *array = a;
        else
                strv_free(a);

        return r;
}

_public_ int sd_uid_get_sessions(uid_t uid, int require_active, char ***sessions) {
        return uid_get_array(
                        uid,
                        require_active == 0 ? "ONLINE_SESSIONS" :
                        require_active > 0  ? "ACTIVE_SESSIONS" :
                                              "SESSIONS",
                        sessions);
}

_public_ int sd_uid_get_seats(uid_t uid, int require_active, char ***seats) {
        return uid_get_array(
                        uid,
                        require_active == 0 ? "ONLINE_SEATS" :
                        require_active > 0  ? "ACTIVE_SEATS" :
                                              "SEATS",
                        seats);
}

static int file_of_session(const char *session, char **_p) {
        char *p;
        int r;

        assert(_p);

        if (session) {
                if (!session_id_valid(session))
                        return -EINVAL;

                p = strappend("/run/systemd/sessions/", session);
        } else {
                _cleanup_free_ char *buf = NULL;

                r = sd_pid_get_session(0, &buf);
                if (r < 0)
                        return r;

                p = strappend("/run/systemd/sessions/", buf);
        }

        if (!p)
                return -ENOMEM;

        *_p = p;
        return 0;
}

_public_ int sd_session_is_active(const char *session) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        r = file_of_session(session, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "ACTIVE", &s, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -EIO;

        return parse_boolean(s);
}

_public_ int sd_session_is_remote(const char *session) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        r = file_of_session(session, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "REMOTE", &s, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -ENODATA;

        return parse_boolean(s);
}

_public_ int sd_session_get_state(const char *session, char **state) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        assert_return(state, -EINVAL);

        r = file_of_session(session, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "STATE", &s, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -EIO;

        *state = s;
        s = NULL;

        return 0;
}

_public_ int sd_session_get_uid(const char *session, uid_t *uid) {
        int r;
        _cleanup_free_ char *p = NULL, *s = NULL;

        assert_return(uid, -EINVAL);

        r = file_of_session(session, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, "UID", &s, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -EIO;

        return parse_uid(s, uid);
}

static int session_get_string(const char *session, const char *field, char **value) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        assert_return(value, -EINVAL);
        assert(field);

        r = file_of_session(session, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE, field, &s, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -ENODATA;

        *value = s;
        s = NULL;
        return 0;
}

_public_ int sd_session_get_seat(const char *session, char **seat) {
        return session_get_string(session, "SEAT", seat);
}

_public_ int sd_session_get_tty(const char *session, char **tty) {
        return session_get_string(session, "TTY", tty);
}

_public_ int sd_session_get_vt(const char *session, unsigned *vtnr) {
        _cleanup_free_ char *vtnr_string = NULL;
        unsigned u;
        int r;

        assert_return(vtnr, -EINVAL);

        r = session_get_string(session, "VTNR", &vtnr_string);
        if (r < 0)
                return r;

        r = safe_atou(vtnr_string, &u);
        if (r < 0)
                return r;

        *vtnr = u;
        return 0;
}

_public_ int sd_session_get_service(const char *session, char **service) {
        return session_get_string(session, "SERVICE", service);
}

_public_ int sd_session_get_type(const char *session, char **type) {
        return session_get_string(session, "TYPE", type);
}

_public_ int sd_session_get_class(const char *session, char **class) {
        return session_get_string(session, "CLASS", class);
}

_public_ int sd_session_get_desktop(const char *session, char **desktop) {
        _cleanup_free_ char *escaped = NULL;
        char *t;
        int r;

        assert_return(desktop, -EINVAL);

        r = session_get_string(session, "DESKTOP", &escaped);
        if (r < 0)
                return r;

        r = cunescape(escaped, 0, &t);
        if (r < 0)
                return r;

        *desktop = t;
        return 0;
}

_public_ int sd_session_get_display(const char *session, char **display) {
        return session_get_string(session, "DISPLAY", display);
}

_public_ int sd_session_get_remote_user(const char *session, char **remote_user) {
        return session_get_string(session, "REMOTE_USER", remote_user);
}

_public_ int sd_session_get_remote_host(const char *session, char **remote_host) {
        return session_get_string(session, "REMOTE_HOST", remote_host);
}

_public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) {
        _cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
        int r;

        assert_return(session || uid, -EINVAL);

        r = file_of_seat(seat, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE,
                           "ACTIVE", &s,
                           "ACTIVE_UID", &t,
                           NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;

        if (session && !s)
                return -ENODATA;

        if (uid && !t)
                return -ENODATA;

        if (uid && t) {
                r = parse_uid(t, uid);
                if (r < 0)
                        return r;
        }

        if (session && s) {
                *session = s;
                s = NULL;
        }

        return 0;
}

_public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **uids, unsigned *n_uids) {
        _cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
        _cleanup_strv_free_ char **a = NULL;
        _cleanup_free_ uid_t *b = NULL;
        unsigned n = 0;
        int r;

        r = file_of_seat(seat, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE,
                           "SESSIONS", &s,
                           "ACTIVE_SESSIONS", &t,
                           NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;

        if (s) {
                a = strv_split(s, " ");
                if (!a)
                        return -ENOMEM;
        }

        if (uids && t) {
                const char *word, *state;
                size_t l;

                FOREACH_WORD(word, l, t, state)
                        n++;

                if (n > 0) {
                        unsigned i = 0;

                        b = new(uid_t, n);
                        if (!b)
                                return -ENOMEM;

                        FOREACH_WORD(word, l, t, state) {
                                _cleanup_free_ char *k = NULL;

                                k = strndup(word, l);
                                if (!k)
                                        return -ENOMEM;

                                r = parse_uid(k, b + i);
                                if (r < 0)
                                        continue;

                                i++;
                        }
                }
        }

        r = strv_length(a);

        if (sessions) {
                *sessions = a;
                a = NULL;
        }

        if (uids) {
                *uids = b;
                b = NULL;
        }

        if (n_uids)
                *n_uids = n;

        return r;
}

static int seat_get_can(const char *seat, const char *variable) {
        _cleanup_free_ char *p = NULL, *s = NULL;
        int r;

        assert(variable);

        r = file_of_seat(seat, &p);
        if (r < 0)
                return r;

        r = parse_env_file(p, NEWLINE,
                           variable, &s,
                           NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (isempty(s))
                return -ENODATA;

        return parse_boolean(s);
}

_public_ int sd_seat_can_multi_session(const char *seat) {
        return seat_get_can(seat, "CAN_MULTI_SESSION");
}

_public_ int sd_seat_can_tty(const char *seat) {
        return seat_get_can(seat, "CAN_TTY");
}

_public_ int sd_seat_can_graphical(const char *seat) {
        return seat_get_can(seat, "CAN_GRAPHICAL");
}

_public_ int sd_get_seats(char ***seats) {
        return get_files_in_directory("/run/systemd/seats/", seats);
}

_public_ int sd_get_sessions(char ***sessions) {
        return get_files_in_directory("/run/systemd/sessions/", sessions);
}

_public_ int sd_get_uids(uid_t **users) {
        _cleanup_closedir_ DIR *d;
        int r = 0;
        unsigned n = 0;
        _cleanup_free_ uid_t *l = NULL;

        d = opendir("/run/systemd/users/");
        if (!d)
                return -errno;

        for (;;) {
                struct dirent *de;
                int k;
                uid_t uid;

                errno = 0;
                de = readdir(d);
                if (!de && errno != 0)
                        return -errno;

                if (!de)
                        break;

                dirent_ensure_type(d, de);

                if (!dirent_is_file(de))
                        continue;

                k = parse_uid(de->d_name, &uid);
                if (k < 0)
                        continue;

                if (users) {
                        if ((unsigned) r >= n) {
                                uid_t *t;

                                n = MAX(16, 2*r);
                                t = realloc(l, sizeof(uid_t) * n);
                                if (!t)
                                        return -ENOMEM;

                                l = t;
                        }

                        assert((unsigned) r < n);
                        l[r++] = uid;
                } else
                        r++;
        }

        if (users) {
                *users = l;
                l = NULL;
        }

        return r;
}

_public_ int sd_get_machine_names(char ***machines) {
        char **l = NULL, **a, **b;
        int r;

        assert_return(machines, -EINVAL);

        r = get_files_in_directory("/run/systemd/machines/", &l);
        if (r < 0)
                return r;

        if (l) {
                r = 0;

                /* Filter out the unit: symlinks */
                for (a = l, b = l; *a; a++) {
                        if (startswith(*a, "unit:") || !machine_name_is_valid(*a))
                                free(*a);
                        else {
                                *b = *a;
                                b++;
                                r++;
                        }
                }

                *b = NULL;
        }

        *machines = l;
        return r;
}

_public_ int sd_machine_get_class(const char *machine, char **class) {
        _cleanup_free_ char *c = NULL;
        const char *p;
        int r;

        assert_return(machine_name_is_valid(machine), -EINVAL);
        assert_return(class, -EINVAL);

        p = strjoina("/run/systemd/machines/", machine);
        r = parse_env_file(p, NEWLINE, "CLASS", &c, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (!c)
                return -EIO;

        *class = c;
        c = NULL;

        return 0;
}

_public_ int sd_machine_get_ifindices(const char *machine, int **ifindices) {
        _cleanup_free_ char *netif = NULL;
        size_t l, allocated = 0, nr = 0;
        int *ni = NULL;
        const char *p, *word, *state;
        int r;

        assert_return(machine_name_is_valid(machine), -EINVAL);
        assert_return(ifindices, -EINVAL);

        p = strjoina("/run/systemd/machines/", machine);
        r = parse_env_file(p, NEWLINE, "NETIF", &netif, NULL);
        if (r == -ENOENT)
                return -ENXIO;
        if (r < 0)
                return r;
        if (!netif) {
                *ifindices = NULL;
                return 0;
        }

        FOREACH_WORD(word, l, netif, state) {
                char buf[l+1];
                int ifi;

                *(char*) (mempcpy(buf, word, l)) = 0;

                if (parse_ifindex(buf, &ifi) < 0)
                        continue;

                if (!GREEDY_REALLOC(ni, allocated, nr+1)) {
                        free(ni);
                        return -ENOMEM;
                }

                ni[nr++] = ifi;
        }

        *ifindices = ni;
        return nr;
}

static inline int MONITOR_TO_FD(sd_login_monitor *m) {
        return (int) (unsigned long) m - 1;
}

static inline sd_login_monitor* FD_TO_MONITOR(int fd) {
        return (sd_login_monitor*) (unsigned long) (fd + 1);
}

_public_ int sd_login_monitor_new(const char *category, sd_login_monitor **m) {
        int fd, k;
        bool good = false;

        assert_return(m, -EINVAL);

        fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
        if (fd < 0)
                return -errno;

        if (!category || streq(category, "seat")) {
                k = inotify_add_watch(fd, "/run/systemd/seats/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!category || streq(category, "session")) {
                k = inotify_add_watch(fd, "/run/systemd/sessions/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!category || streq(category, "uid")) {
                k = inotify_add_watch(fd, "/run/systemd/users/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!category || streq(category, "machine")) {
                k = inotify_add_watch(fd, "/run/systemd/machines/", IN_MOVED_TO|IN_DELETE);
                if (k < 0) {
                        safe_close(fd);
                        return -errno;
                }

                good = true;
        }

        if (!good) {
                close_nointr(fd);
                return -EINVAL;
        }

        *m = FD_TO_MONITOR(fd);
        return 0;
}

_public_ sd_login_monitor* sd_login_monitor_unref(sd_login_monitor *m) {
        int fd;

        assert_return(m, NULL);

        fd = MONITOR_TO_FD(m);
        close_nointr(fd);

        return NULL;
}

_public_ int sd_login_monitor_flush(sd_login_monitor *m) {

        assert_return(m, -EINVAL);

        return flush_fd(MONITOR_TO_FD(m));
}

_public_ int sd_login_monitor_get_fd(sd_login_monitor *m) {

        assert_return(m, -EINVAL);

        return MONITOR_TO_FD(m);
}

_public_ int sd_login_monitor_get_events(sd_login_monitor *m) {

        assert_return(m, -EINVAL);

        /* For now we will only return POLLIN here, since we don't
         * need anything else ever for inotify.  However, let's have
         * this API to keep our options open should we later on need
         * it. */
        return POLLIN;
}

_public_ int sd_login_monitor_get_timeout(sd_login_monitor *m, uint64_t *timeout_usec) {

        assert_return(m, -EINVAL);
        assert_return(timeout_usec, -EINVAL);

        /* For now we will only return (uint64_t) -1, since we don't
         * need any timeout. However, let's have this API to keep our
         * options open should we later on need it. */
        *timeout_usec = (uint64_t) -1;
        return 0;
}