summaryrefslogtreecommitdiffstats
path: root/src/core/swap.c
blob: 2d8463b8b1812173ec019b0274eaf4d39799cff0 (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
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
/* SPDX-License-Identifier: LGPL-2.1+ */

#include <errno.h>
#include <sys/epoll.h>
#include <sys/stat.h>
#include <unistd.h>

#include "sd-device.h"

#include "alloc-util.h"
#include "dbus-swap.h"
#include "dbus-unit.h"
#include "device-private.h"
#include "device-util.h"
#include "device.h"
#include "escape.h"
#include "exit-status.h"
#include "fd-util.h"
#include "format-util.h"
#include "fstab-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"
#include "serialize.h"
#include "special.h"
#include "string-table.h"
#include "string-util.h"
#include "swap.h"
#include "unit-name.h"
#include "unit.h"
#include "virt.h"

static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = {
        [SWAP_DEAD] = UNIT_INACTIVE,
        [SWAP_ACTIVATING] = UNIT_ACTIVATING,
        [SWAP_ACTIVATING_DONE] = UNIT_ACTIVE,
        [SWAP_ACTIVE] = UNIT_ACTIVE,
        [SWAP_DEACTIVATING] = UNIT_DEACTIVATING,
        [SWAP_DEACTIVATING_SIGTERM] = UNIT_DEACTIVATING,
        [SWAP_DEACTIVATING_SIGKILL] = UNIT_DEACTIVATING,
        [SWAP_FAILED] = UNIT_FAILED
};

static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata);
static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);

static bool SWAP_STATE_WITH_PROCESS(SwapState state) {
        return IN_SET(state,
                      SWAP_ACTIVATING,
                      SWAP_ACTIVATING_DONE,
                      SWAP_DEACTIVATING,
                      SWAP_DEACTIVATING_SIGTERM,
                      SWAP_DEACTIVATING_SIGKILL);
}

static void swap_unset_proc_swaps(Swap *s) {
        assert(s);

        if (!s->from_proc_swaps)
                return;

        s->parameters_proc_swaps.what = mfree(s->parameters_proc_swaps.what);

        s->from_proc_swaps = false;
}

static int swap_set_devnode(Swap *s, const char *devnode) {
        Hashmap *swaps;
        Swap *first;
        int r;

        assert(s);

        r = hashmap_ensure_allocated(&UNIT(s)->manager->swaps_by_devnode, &path_hash_ops);
        if (r < 0)
                return r;

        swaps = UNIT(s)->manager->swaps_by_devnode;

        if (s->devnode) {
                first = hashmap_get(swaps, s->devnode);

                LIST_REMOVE(same_devnode, first, s);
                if (first)
                        hashmap_replace(swaps, first->devnode, first);
                else
                        hashmap_remove(swaps, s->devnode);

                s->devnode = mfree(s->devnode);
        }

        if (devnode) {
                s->devnode = strdup(devnode);
                if (!s->devnode)
                        return -ENOMEM;

                first = hashmap_get(swaps, s->devnode);
                LIST_PREPEND(same_devnode, first, s);

                return hashmap_replace(swaps, first->devnode, first);
        }

        return 0;
}

static void swap_init(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);
        assert(UNIT(s)->load_state == UNIT_STUB);

        s->timeout_usec = u->manager->default_timeout_start_usec;

        s->exec_context.std_output = u->manager->default_std_output;
        s->exec_context.std_error = u->manager->default_std_error;

        s->parameters_proc_swaps.priority = s->parameters_fragment.priority = -1;

        s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;

        u->ignore_on_isolate = true;
}

static void swap_unwatch_control_pid(Swap *s) {
        assert(s);

        if (s->control_pid <= 0)
                return;

        unit_unwatch_pid(UNIT(s), s->control_pid);
        s->control_pid = 0;
}

static void swap_done(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);

        swap_unset_proc_swaps(s);
        swap_set_devnode(s, NULL);

        s->what = mfree(s->what);
        s->parameters_fragment.what = mfree(s->parameters_fragment.what);
        s->parameters_fragment.options = mfree(s->parameters_fragment.options);

        s->exec_runtime = exec_runtime_unref(s->exec_runtime, false);
        exec_command_done_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX);
        s->control_command = NULL;

        dynamic_creds_unref(&s->dynamic_creds);

        swap_unwatch_control_pid(s);

        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
}

static int swap_arm_timer(Swap *s, usec_t usec) {
        int r;

        assert(s);

        if (s->timer_event_source) {
                r = sd_event_source_set_time(s->timer_event_source, usec);
                if (r < 0)
                        return r;

                return sd_event_source_set_enabled(s->timer_event_source, SD_EVENT_ONESHOT);
        }

        if (usec == USEC_INFINITY)
                return 0;

        r = sd_event_add_time(
                        UNIT(s)->manager->event,
                        &s->timer_event_source,
                        CLOCK_MONOTONIC,
                        usec, 0,
                        swap_dispatch_timer, s);
        if (r < 0)
                return r;

        (void) sd_event_source_set_description(s->timer_event_source, "swap-timer");

        return 0;
}

static int swap_add_device_dependencies(Swap *s) {
        assert(s);

        if (!s->what)
                return 0;

        if (!s->from_fragment)
                return 0;

        if (is_device_path(s->what))
                return unit_add_node_dependency(UNIT(s), s->what, MANAGER_IS_SYSTEM(UNIT(s)->manager), UNIT_BINDS_TO, UNIT_DEPENDENCY_FILE);
        else
                /* File based swap devices need to be ordered after
                 * systemd-remount-fs.service, since they might need a
                 * writable file system. */
                return unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, SPECIAL_REMOUNT_FS_SERVICE, true, UNIT_DEPENDENCY_FILE);
}

static int swap_add_default_dependencies(Swap *s) {
        int r;

        assert(s);

        if (!UNIT(s)->default_dependencies)
                return 0;

        if (!MANAGER_IS_SYSTEM(UNIT(s)->manager))
                return 0;

        if (detect_container() > 0)
                return 0;

        /* swap units generated for the swap dev links are missing the
         * ordering dep against the swap target. */
        r = unit_add_dependency_by_name(UNIT(s), UNIT_BEFORE, SPECIAL_SWAP_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
        if (r < 0)
                return r;

        return unit_add_two_dependencies_by_name(UNIT(s), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
}

static int swap_verify(Swap *s) {
        _cleanup_free_ char *e = NULL;
        int r;

        if (UNIT(s)->load_state != UNIT_LOADED)
                return 0;

        r = unit_name_from_path(s->what, ".swap", &e);
        if (r < 0)
                return log_unit_error_errno(UNIT(s), r, "Failed to generate unit name from path: %m");

        if (!unit_has_name(UNIT(s), e)) {
                log_unit_error(UNIT(s), "Value of What= and unit name do not match, not loading.");
                return -ENOEXEC;
        }

        if (s->exec_context.pam_name && s->kill_context.kill_mode != KILL_CONTROL_GROUP) {
                log_unit_error(UNIT(s), "Unit has PAM enabled. Kill mode must be set to 'control-group'. Refusing to load.");
                return -ENOEXEC;
        }

        return 0;
}

static int swap_load_devnode(Swap *s) {
        _cleanup_(sd_device_unrefp) sd_device *d = NULL;
        struct stat st;
        const char *p;
        int r;

        assert(s);

        if (stat(s->what, &st) < 0 || !S_ISBLK(st.st_mode))
                return 0;

        r = device_new_from_stat_rdev(&d, &st);
        if (r < 0) {
                log_unit_full(UNIT(s), r == -ENOENT ? LOG_DEBUG : LOG_WARNING, r,
                              "Failed to allocate device for swap %s: %m", s->what);
                return 0;
        }

        if (sd_device_get_devname(d, &p) < 0)
                return 0;

        return swap_set_devnode(s, p);
}

static int swap_add_extras(Swap *s) {
        int r;

        assert(s);

        if (UNIT(s)->fragment_path)
                s->from_fragment = true;

        if (!s->what) {
                if (s->parameters_fragment.what)
                        s->what = strdup(s->parameters_fragment.what);
                else if (s->parameters_proc_swaps.what)
                        s->what = strdup(s->parameters_proc_swaps.what);
                else {
                        r = unit_name_to_path(UNIT(s)->id, &s->what);
                        if (r < 0)
                                return r;
                }

                if (!s->what)
                        return -ENOMEM;
        }

        path_simplify(s->what, false);

        if (!UNIT(s)->description) {
                r = unit_set_description(UNIT(s), s->what);
                if (r < 0)
                        return r;
        }

        r = unit_require_mounts_for(UNIT(s), s->what, UNIT_DEPENDENCY_IMPLICIT);
        if (r < 0)
                return r;

        r = swap_add_device_dependencies(s);
        if (r < 0)
                return r;

        r = swap_load_devnode(s);
        if (r < 0)
                return r;

        r = unit_patch_contexts(UNIT(s));
        if (r < 0)
                return r;

        r = unit_add_exec_dependencies(UNIT(s), &s->exec_context);
        if (r < 0)
                return r;

        r = unit_set_default_slice(UNIT(s));
        if (r < 0)
                return r;

        r = swap_add_default_dependencies(s);
        if (r < 0)
                return r;

        return 0;
}

static int swap_load(Unit *u) {
        Swap *s = SWAP(u);
        int r, q;

        assert(s);
        assert(u->load_state == UNIT_STUB);

        /* Load a .swap file */
        if (SWAP(u)->from_proc_swaps)
                r = unit_load_fragment_and_dropin_optional(u);
        else
                r = unit_load_fragment_and_dropin(u);

        /* Add in some extras, and do so either when we successfully loaded something or when /proc/swaps is already
         * active. */
        if (u->load_state == UNIT_LOADED || s->from_proc_swaps)
                q = swap_add_extras(s);
        else
                q = 0;

        if (r < 0)
                return r;
        if (q < 0)
                return q;

        return swap_verify(s);
}

static int swap_setup_unit(
                Manager *m,
                const char *what,
                const char *what_proc_swaps,
                int priority,
                bool set_flags) {

        _cleanup_free_ char *e = NULL;
        bool delete = false;
        Unit *u = NULL;
        int r;
        SwapParameters *p;

        assert(m);
        assert(what);
        assert(what_proc_swaps);

        r = unit_name_from_path(what, ".swap", &e);
        if (r < 0)
                return log_unit_error_errno(u, r, "Failed to generate unit name from path: %m");

        u = manager_get_unit(m, e);
        if (u &&
            SWAP(u)->from_proc_swaps &&
            !path_equal(SWAP(u)->parameters_proc_swaps.what, what_proc_swaps))
                return log_error_errno(SYNTHETIC_ERRNO(EEXIST),
                                       "Swap %s appeared twice with different device paths %s and %s",
                                       e, SWAP(u)->parameters_proc_swaps.what, what_proc_swaps);

        if (!u) {
                delete = true;

                r = unit_new_for_name(m, sizeof(Swap), e, &u);
                if (r < 0)
                        goto fail;

                SWAP(u)->what = strdup(what);
                if (!SWAP(u)->what) {
                        r = -ENOMEM;
                        goto fail;
                }

                unit_add_to_load_queue(u);
        } else
                delete = false;

        p = &SWAP(u)->parameters_proc_swaps;

        if (!p->what) {
                p->what = strdup(what_proc_swaps);
                if (!p->what) {
                        r = -ENOMEM;
                        goto fail;
                }
        }

        /* The unit is definitely around now, mark it as loaded if it was previously referenced but could not be
         * loaded. After all we can load it now, from the data in /proc/swaps. */
        if (IN_SET(u->load_state, UNIT_NOT_FOUND, UNIT_BAD_SETTING, UNIT_ERROR)) {
                u->load_state = UNIT_LOADED;
                u->load_error = 0;
        }

        if (set_flags) {
                SWAP(u)->is_active = true;
                SWAP(u)->just_activated = !SWAP(u)->from_proc_swaps;
        }

        SWAP(u)->from_proc_swaps = true;

        p->priority = priority;

        unit_add_to_dbus_queue(u);
        return 0;

fail:
        log_unit_warning_errno(u, r, "Failed to load swap unit: %m");

        if (delete)
                unit_free(u);

        return r;
}

static int swap_process_new(Manager *m, const char *device, int prio, bool set_flags) {
        _cleanup_(sd_device_unrefp) sd_device *d = NULL;
        const char *dn, *devlink;
        struct stat st, st_link;
        int r;

        assert(m);

        r = swap_setup_unit(m, device, device, prio, set_flags);
        if (r < 0)
                return r;

        /* If this is a block device, then let's add duplicates for
         * all other names of this block device */
        if (stat(device, &st) < 0 || !S_ISBLK(st.st_mode))
                return 0;

        r = device_new_from_stat_rdev(&d, &st);
        if (r < 0) {
                log_full_errno(r == -ENOENT ? LOG_DEBUG : LOG_WARNING, r,
                               "Failed to allocate device for swap %s: %m", device);
                return 0;
        }

        /* Add the main device node */
        if (sd_device_get_devname(d, &dn) >= 0 && !streq(dn, device))
                swap_setup_unit(m, dn, device, prio, set_flags);

        /* Add additional units for all symlinks */
        FOREACH_DEVICE_DEVLINK(d, devlink) {

                /* Don't bother with the /dev/block links */
                if (streq(devlink, device))
                        continue;

                if (path_startswith(devlink, "/dev/block/"))
                        continue;

                if (stat(devlink, &st_link) >= 0 &&
                    (!S_ISBLK(st_link.st_mode) ||
                     st_link.st_rdev != st.st_rdev))
                        continue;

                swap_setup_unit(m, devlink, device, prio, set_flags);
        }

        return 0;
}

static void swap_set_state(Swap *s, SwapState state) {
        SwapState old_state;
        Swap *other;

        assert(s);

        if (s->state != state)
                bus_unit_send_pending_change_signal(UNIT(s), false);

        old_state = s->state;
        s->state = state;

        if (!SWAP_STATE_WITH_PROCESS(state)) {
                s->timer_event_source = sd_event_source_unref(s->timer_event_source);
                swap_unwatch_control_pid(s);
                s->control_command = NULL;
                s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
        }

        if (state != old_state)
                log_unit_debug(UNIT(s), "Changed %s -> %s", swap_state_to_string(old_state), swap_state_to_string(state));

        unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], 0);

        /* If there other units for the same device node have a job
           queued it might be worth checking again if it is runnable
           now. This is necessary, since swap_start() refuses
           operation with EAGAIN if there's already another job for
           the same device node queued. */
        LIST_FOREACH_OTHERS(same_devnode, other, s)
                if (UNIT(other)->job)
                        job_add_to_run_queue(UNIT(other)->job);
}

static int swap_coldplug(Unit *u) {
        Swap *s = SWAP(u);
        SwapState new_state = SWAP_DEAD;
        int r;

        assert(s);
        assert(s->state == SWAP_DEAD);

        if (s->deserialized_state != s->state)
                new_state = s->deserialized_state;
        else if (s->from_proc_swaps)
                new_state = SWAP_ACTIVE;

        if (new_state == s->state)
                return 0;

        if (s->control_pid > 0 &&
            pid_is_unwaited(s->control_pid) &&
            SWAP_STATE_WITH_PROCESS(new_state)) {

                r = unit_watch_pid(UNIT(s), s->control_pid);
                if (r < 0)
                        return r;

                r = swap_arm_timer(s, usec_add(u->state_change_timestamp.monotonic, s->timeout_usec));
                if (r < 0)
                        return r;
        }

        if (!IN_SET(new_state, SWAP_DEAD, SWAP_FAILED)) {
                (void) unit_setup_dynamic_creds(u);
                (void) unit_setup_exec_runtime(u);
        }

        swap_set_state(s, new_state);
        return 0;
}

static void swap_dump(Unit *u, FILE *f, const char *prefix) {
        char buf[FORMAT_TIMESPAN_MAX];
        Swap *s = SWAP(u);
        SwapParameters *p;

        assert(s);
        assert(f);

        if (s->from_proc_swaps)
                p = &s->parameters_proc_swaps;
        else if (s->from_fragment)
                p = &s->parameters_fragment;
        else
                p = NULL;

        fprintf(f,
                "%sSwap State: %s\n"
                "%sResult: %s\n"
                "%sWhat: %s\n"
                "%sFrom /proc/swaps: %s\n"
                "%sFrom fragment: %s\n",
                prefix, swap_state_to_string(s->state),
                prefix, swap_result_to_string(s->result),
                prefix, s->what,
                prefix, yes_no(s->from_proc_swaps),
                prefix, yes_no(s->from_fragment));

        if (s->devnode)
                fprintf(f, "%sDevice Node: %s\n", prefix, s->devnode);

        if (p)
                fprintf(f,
                        "%sPriority: %i\n"
                        "%sOptions: %s\n",
                        prefix, p->priority,
                        prefix, strempty(p->options));

        fprintf(f,
                "%sTimeoutSec: %s\n",
                prefix, format_timespan(buf, sizeof(buf), s->timeout_usec, USEC_PER_SEC));

        if (s->control_pid > 0)
                fprintf(f,
                        "%sControl PID: "PID_FMT"\n",
                        prefix, s->control_pid);

        exec_context_dump(&s->exec_context, f, prefix);
        kill_context_dump(&s->kill_context, f, prefix);
        cgroup_context_dump(&s->cgroup_context, f, prefix);
}

static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {

        _cleanup_(exec_params_clear) ExecParameters exec_params = {
                .flags     = EXEC_APPLY_SANDBOXING|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN,
                .stdin_fd  = -1,
                .stdout_fd = -1,
                .stderr_fd = -1,
                .exec_fd   = -1,
        };
        pid_t pid;
        int r;

        assert(s);
        assert(c);
        assert(_pid);

        r = unit_prepare_exec(UNIT(s));
        if (r < 0)
                return r;

        r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec));
        if (r < 0)
                goto fail;

        r = unit_set_exec_params(UNIT(s), &exec_params);
        if (r < 0)
                goto fail;

        r = exec_spawn(UNIT(s),
                       c,
                       &s->exec_context,
                       &exec_params,
                       s->exec_runtime,
                       &s->dynamic_creds,
                       &pid);
        if (r < 0)
                goto fail;

        r = unit_watch_pid(UNIT(s), pid);
        if (r < 0)
                /* FIXME: we need to do something here */
                goto fail;

        *_pid = pid;

        return 0;

fail:
        s->timer_event_source = sd_event_source_unref(s->timer_event_source);

        return r;
}

static void swap_enter_dead(Swap *s, SwapResult f) {
        assert(s);

        if (s->result == SWAP_SUCCESS)
                s->result = f;

        unit_log_result(UNIT(s), s->result == SWAP_SUCCESS, swap_result_to_string(s->result));
        swap_set_state(s, s->result != SWAP_SUCCESS ? SWAP_FAILED : SWAP_DEAD);

        s->exec_runtime = exec_runtime_unref(s->exec_runtime, true);

        exec_context_destroy_runtime_directory(&s->exec_context, UNIT(s)->manager->prefix[EXEC_DIRECTORY_RUNTIME]);

        unit_unref_uid_gid(UNIT(s), true);

        dynamic_creds_destroy(&s->dynamic_creds);
}

static void swap_enter_active(Swap *s, SwapResult f) {
        assert(s);

        if (s->result == SWAP_SUCCESS)
                s->result = f;

        swap_set_state(s, SWAP_ACTIVE);
}

static void swap_enter_dead_or_active(Swap *s, SwapResult f) {
        assert(s);

        if (s->from_proc_swaps)
                swap_enter_active(s, f);
        else
                swap_enter_dead(s, f);
}

static void swap_enter_signal(Swap *s, SwapState state, SwapResult f) {
        int r;
        KillOperation kop;

        assert(s);

        if (s->result == SWAP_SUCCESS)
                s->result = f;

        if (state == SWAP_DEACTIVATING_SIGTERM)
                kop = KILL_TERMINATE;
        else
                kop = KILL_KILL;

        r = unit_kill_context(UNIT(s), &s->kill_context, kop, -1, s->control_pid, false);
        if (r < 0)
                goto fail;

        if (r > 0) {
                r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec));
                if (r < 0)
                        goto fail;

                swap_set_state(s, state);
        } else if (state == SWAP_DEACTIVATING_SIGTERM && s->kill_context.send_sigkill)
                swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_SUCCESS);
        else
                swap_enter_dead_or_active(s, SWAP_SUCCESS);

        return;

fail:
        log_unit_warning_errno(UNIT(s), r, "Failed to kill processes: %m");
        swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES);
}

static void swap_enter_activating(Swap *s) {
        _cleanup_free_ char *opts = NULL;
        int r;

        assert(s);

        unit_warn_leftover_processes(UNIT(s));

        s->control_command_id = SWAP_EXEC_ACTIVATE;
        s->control_command = s->exec_command + SWAP_EXEC_ACTIVATE;

        if (s->from_fragment) {
                int priority = -1;

                r = fstab_find_pri(s->parameters_fragment.options, &priority);
                if (r < 0)
                        log_warning_errno(r, "Failed to parse swap priority \"%s\", ignoring: %m", s->parameters_fragment.options);
                else if (r == 1 && s->parameters_fragment.priority >= 0)
                        log_warning("Duplicate swap priority configuration by Priority and Options fields.");

                if (r <= 0 && s->parameters_fragment.priority >= 0) {
                        if (s->parameters_fragment.options)
                                r = asprintf(&opts, "%s,pri=%i", s->parameters_fragment.options, s->parameters_fragment.priority);
                        else
                                r = asprintf(&opts, "pri=%i", s->parameters_fragment.priority);
                        if (r < 0)
                                goto fail;
                }
        }

        r = exec_command_set(s->control_command, "/sbin/swapon", NULL);
        if (r < 0)
                goto fail;

        if (s->parameters_fragment.options || opts) {
                r = exec_command_append(s->control_command, "-o",
                                opts ? : s->parameters_fragment.options, NULL);
                if (r < 0)
                        goto fail;
        }

        r = exec_command_append(s->control_command, s->what, NULL);
        if (r < 0)
                goto fail;

        swap_unwatch_control_pid(s);

        r = swap_spawn(s, s->control_command, &s->control_pid);
        if (r < 0)
                goto fail;

        swap_set_state(s, SWAP_ACTIVATING);

        return;

fail:
        log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapon' task: %m");
        swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES);
}

static void swap_enter_deactivating(Swap *s) {
        int r;

        assert(s);

        s->control_command_id = SWAP_EXEC_DEACTIVATE;
        s->control_command = s->exec_command + SWAP_EXEC_DEACTIVATE;

        r = exec_command_set(s->control_command,
                             "/sbin/swapoff",
                             s->what,
                             NULL);
        if (r < 0)
                goto fail;

        swap_unwatch_control_pid(s);

        r = swap_spawn(s, s->control_command, &s->control_pid);
        if (r < 0)
                goto fail;

        swap_set_state(s, SWAP_DEACTIVATING);

        return;

fail:
        log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapoff' task: %m");
        swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES);
}

static void swap_cycle_clear(Swap *s) {
        assert(s);

        s->result = SWAP_SUCCESS;
        exec_command_reset_status_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX);
        UNIT(s)->reset_accounting = true;
}

static int swap_start(Unit *u) {
        Swap *s = SWAP(u), *other;
        int r;

        assert(s);

        /* We cannot fulfill this request right now, try again later please! */
        if (IN_SET(s->state,
                   SWAP_DEACTIVATING,
                   SWAP_DEACTIVATING_SIGTERM,
                   SWAP_DEACTIVATING_SIGKILL))
                return -EAGAIN;

        /* Already on it! */
        if (s->state == SWAP_ACTIVATING)
                return 0;

        assert(IN_SET(s->state, SWAP_DEAD, SWAP_FAILED));

        if (detect_container() > 0)
                return -EPERM;

        /* If there's a job for another swap unit for the same node
         * running, then let's not dispatch this one for now, and wait
         * until that other job has finished. */
        LIST_FOREACH_OTHERS(same_devnode, other, s)
                if (UNIT(other)->job && UNIT(other)->job->state == JOB_RUNNING)
                        return -EAGAIN;

        r = unit_start_limit_test(u);
        if (r < 0) {
                swap_enter_dead(s, SWAP_FAILURE_START_LIMIT_HIT);
                return r;
        }

        r = unit_acquire_invocation_id(u);
        if (r < 0)
                return r;

        swap_cycle_clear(s);
        swap_enter_activating(s);
        return 1;
}

static int swap_stop(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);

        switch (s->state) {

        case SWAP_DEACTIVATING:
        case SWAP_DEACTIVATING_SIGTERM:
        case SWAP_DEACTIVATING_SIGKILL:
                /* Already on it */
                return 0;

        case SWAP_ACTIVATING:
        case SWAP_ACTIVATING_DONE:
                /* There's a control process pending, directly enter kill mode */
                swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_SUCCESS);
                return 0;

        case SWAP_ACTIVE:
                if (detect_container() > 0)
                        return -EPERM;

                swap_enter_deactivating(s);
                return 1;

        default:
                assert_not_reached("Unexpected state.");
        }
}

static int swap_serialize(Unit *u, FILE *f, FDSet *fds) {
        Swap *s = SWAP(u);

        assert(s);
        assert(f);
        assert(fds);

        (void) serialize_item(f, "state", swap_state_to_string(s->state));
        (void) serialize_item(f, "result", swap_result_to_string(s->result));

        if (s->control_pid > 0)
                (void) serialize_item_format(f, "control-pid", PID_FMT, s->control_pid);

        if (s->control_command_id >= 0)
                (void) serialize_item(f, "control-command", swap_exec_command_to_string(s->control_command_id));

        return 0;
}

static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
        Swap *s = SWAP(u);

        assert(s);
        assert(fds);

        if (streq(key, "state")) {
                SwapState state;

                state = swap_state_from_string(value);
                if (state < 0)
                        log_unit_debug(u, "Failed to parse state value: %s", value);
                else
                        s->deserialized_state = state;
        } else if (streq(key, "result")) {
                SwapResult f;

                f = swap_result_from_string(value);
                if (f < 0)
                        log_unit_debug(u, "Failed to parse result value: %s", value);
                else if (f != SWAP_SUCCESS)
                        s->result = f;
        } else if (streq(key, "control-pid")) {
                pid_t pid;

                if (parse_pid(value, &pid) < 0)
                        log_unit_debug(u, "Failed to parse control-pid value: %s", value);
                else
                        s->control_pid = pid;

        } else if (streq(key, "control-command")) {
                SwapExecCommand id;

                id = swap_exec_command_from_string(value);
                if (id < 0)
                        log_unit_debug(u, "Failed to parse exec-command value: %s", value);
                else {
                        s->control_command_id = id;
                        s->control_command = s->exec_command + id;
                }
        } else
                log_unit_debug(u, "Unknown serialization key: %s", key);

        return 0;
}

_pure_ static UnitActiveState swap_active_state(Unit *u) {
        assert(u);

        return state_translation_table[SWAP(u)->state];
}

_pure_ static const char *swap_sub_state_to_string(Unit *u) {
        assert(u);

        return swap_state_to_string(SWAP(u)->state);
}

_pure_ static bool swap_may_gc(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);

        if (s->from_proc_swaps)
                return false;

        return true;
}

static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) {
        Swap *s = SWAP(u);
        SwapResult f;

        assert(s);
        assert(pid >= 0);

        if (pid != s->control_pid)
                return;

        s->control_pid = 0;

        if (is_clean_exit(code, status, EXIT_CLEAN_COMMAND, NULL))
                f = SWAP_SUCCESS;
        else if (code == CLD_EXITED)
                f = SWAP_FAILURE_EXIT_CODE;
        else if (code == CLD_KILLED)
                f = SWAP_FAILURE_SIGNAL;
        else if (code == CLD_DUMPED)
                f = SWAP_FAILURE_CORE_DUMP;
        else
                assert_not_reached("Unknown code");

        if (s->result == SWAP_SUCCESS)
                s->result = f;

        if (s->control_command) {
                exec_status_exit(&s->control_command->exec_status, &s->exec_context, pid, code, status);

                s->control_command = NULL;
                s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
        }

        unit_log_process_exit(
                        u, f == SWAP_SUCCESS ? LOG_DEBUG : LOG_NOTICE,
                        "Swap process",
                        swap_exec_command_to_string(s->control_command_id),
                        code, status);

        switch (s->state) {

        case SWAP_ACTIVATING:
        case SWAP_ACTIVATING_DONE:

                if (f == SWAP_SUCCESS || s->from_proc_swaps)
                        swap_enter_active(s, f);
                else
                        swap_enter_dead(s, f);
                break;

        case SWAP_DEACTIVATING:
        case SWAP_DEACTIVATING_SIGKILL:
        case SWAP_DEACTIVATING_SIGTERM:

                swap_enter_dead_or_active(s, f);
                break;

        default:
                assert_not_reached("Uh, control process died at wrong time.");
        }

        /* Notify clients about changed exit status */
        unit_add_to_dbus_queue(u);
}

static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
        Swap *s = SWAP(userdata);

        assert(s);
        assert(s->timer_event_source == source);

        switch (s->state) {

        case SWAP_ACTIVATING:
        case SWAP_ACTIVATING_DONE:
                log_unit_warning(UNIT(s), "Activation timed out. Stopping.");
                swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT);
                break;

        case SWAP_DEACTIVATING:
                log_unit_warning(UNIT(s), "Deactivation timed out. Stopping.");
                swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT);
                break;

        case SWAP_DEACTIVATING_SIGTERM:
                if (s->kill_context.send_sigkill) {
                        log_unit_warning(UNIT(s), "Swap process timed out. Killing.");
                        swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_FAILURE_TIMEOUT);
                } else {
                        log_unit_warning(UNIT(s), "Swap process timed out. Skipping SIGKILL. Ignoring.");
                        swap_enter_dead_or_active(s, SWAP_FAILURE_TIMEOUT);
                }
                break;

        case SWAP_DEACTIVATING_SIGKILL:
                log_unit_warning(UNIT(s), "Swap process still around after SIGKILL. Ignoring.");
                swap_enter_dead_or_active(s, SWAP_FAILURE_TIMEOUT);
                break;

        default:
                assert_not_reached("Timeout at wrong time.");
        }

        return 0;
}

static int swap_load_proc_swaps(Manager *m, bool set_flags) {
        unsigned i;

        assert(m);

        rewind(m->proc_swaps);

        (void) fscanf(m->proc_swaps, "%*s %*s %*s %*s %*s\n");

        for (i = 1;; i++) {
                _cleanup_free_ char *dev = NULL, *d = NULL;
                int prio = 0, k;

                k = fscanf(m->proc_swaps,
                           "%ms "  /* device/file */
                           "%*s "  /* type of swap */
                           "%*s "  /* swap size */
                           "%*s "  /* used */
                           "%i\n", /* priority */
                           &dev, &prio);
                if (k != 2) {
                        if (k == EOF)
                                break;

                        log_warning("Failed to parse /proc/swaps:%u.", i);
                        continue;
                }

                if (cunescape(dev, UNESCAPE_RELAX, &d) < 0)
                        return log_oom();

                device_found_node(m, d, DEVICE_FOUND_SWAP, DEVICE_FOUND_SWAP);

                (void) swap_process_new(m, d, prio, set_flags);
        }

        return 0;
}

static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
        Manager *m = userdata;
        Unit *u;
        int r;

        assert(m);
        assert(revents & EPOLLPRI);

        r = swap_load_proc_swaps(m, true);
        if (r < 0) {
                log_error_errno(r, "Failed to reread /proc/swaps: %m");

                /* Reset flags, just in case, for late calls */
                LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) {
                        Swap *swap = SWAP(u);

                        swap->is_active = swap->just_activated = false;
                }

                return 0;
        }

        manager_dispatch_load_queue(m);

        LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) {
                Swap *swap = SWAP(u);

                if (!swap->is_active) {

                        swap_unset_proc_swaps(swap);

                        switch (swap->state) {

                        case SWAP_ACTIVE:
                                /* This has just been deactivated */
                                swap_enter_dead(swap, SWAP_SUCCESS);
                                break;

                        default:
                                /* Fire again */
                                swap_set_state(swap, swap->state);
                                break;
                        }

                        if (swap->what)
                                device_found_node(m, swap->what, 0, DEVICE_FOUND_SWAP);

                } else if (swap->just_activated) {

                        /* New swap entry */

                        switch (swap->state) {

                        case SWAP_DEAD:
                        case SWAP_FAILED:
                                (void) unit_acquire_invocation_id(u);
                                swap_cycle_clear(swap);
                                swap_enter_active(swap, SWAP_SUCCESS);
                                break;

                        case SWAP_ACTIVATING:
                                swap_set_state(swap, SWAP_ACTIVATING_DONE);
                                break;

                        default:
                                /* Nothing really changed, but let's
                                 * issue an notification call
                                 * nonetheless, in case somebody is
                                 * waiting for this. */
                                swap_set_state(swap, swap->state);
                                break;
                        }
                }

                /* Reset the flags for later calls */
                swap->is_active = swap->just_activated = false;
        }

        return 1;
}

static Unit *swap_following(Unit *u) {
        Swap *s = SWAP(u);
        Swap *other, *first = NULL;

        assert(s);

        /* If the user configured the swap through /etc/fstab or
         * a device unit, follow that. */

        if (s->from_fragment)
                return NULL;

        LIST_FOREACH_OTHERS(same_devnode, other, s)
                if (other->from_fragment)
                        return UNIT(other);

        /* Otherwise, make everybody follow the unit that's named after
         * the swap device in the kernel */

        if (streq_ptr(s->what, s->devnode))
                return NULL;

        LIST_FOREACH_AFTER(same_devnode, other, s)
                if (streq_ptr(other->what, other->devnode))
                        return UNIT(other);

        LIST_FOREACH_BEFORE(same_devnode, other, s) {
                if (streq_ptr(other->what, other->devnode))
                        return UNIT(other);

                first = other;
        }

        /* Fall back to the first on the list */
        return UNIT(first);
}

static int swap_following_set(Unit *u, Set **_set) {
        Swap *s = SWAP(u), *other;
        _cleanup_set_free_ Set *set = NULL;
        int r;

        assert(s);
        assert(_set);

        if (LIST_JUST_US(same_devnode, s)) {
                *_set = NULL;
                return 0;
        }

        set = set_new(NULL);
        if (!set)
                return -ENOMEM;

        LIST_FOREACH_OTHERS(same_devnode, other, s) {
                r = set_put(set, other);
                if (r < 0)
                        return r;
        }

        *_set = TAKE_PTR(set);
        return 1;
}

static void swap_shutdown(Manager *m) {
        assert(m);

        m->swap_event_source = sd_event_source_unref(m->swap_event_source);
        m->proc_swaps = safe_fclose(m->proc_swaps);
        m->swaps_by_devnode = hashmap_free(m->swaps_by_devnode);
}

static void swap_enumerate(Manager *m) {
        int r;

        assert(m);

        if (!m->proc_swaps) {
                m->proc_swaps = fopen("/proc/swaps", "re");
                if (!m->proc_swaps) {
                        if (errno == ENOENT)
                                log_debug_errno(errno, "Not swap enabled, skipping enumeration.");
                        else
                                log_warning_errno(errno, "Failed to open /proc/swaps, ignoring: %m");

                        return;
                }

                r = sd_event_add_io(m->event, &m->swap_event_source, fileno(m->proc_swaps), EPOLLPRI, swap_dispatch_io, m);
                if (r < 0) {
                        log_error_errno(r, "Failed to watch /proc/swaps: %m");
                        goto fail;
                }

                /* Dispatch this before we dispatch SIGCHLD, so that
                 * we always get the events from /proc/swaps before
                 * the SIGCHLD of /sbin/swapon. */
                r = sd_event_source_set_priority(m->swap_event_source, SD_EVENT_PRIORITY_NORMAL-10);
                if (r < 0) {
                        log_error_errno(r, "Failed to change /proc/swaps priority: %m");
                        goto fail;
                }

                (void) sd_event_source_set_description(m->swap_event_source, "swap-proc");
        }

        r = swap_load_proc_swaps(m, false);
        if (r < 0)
                goto fail;

        return;

fail:
        swap_shutdown(m);
}

int swap_process_device_new(Manager *m, sd_device *dev) {
        _cleanup_free_ char *e = NULL;
        const char *dn, *devlink;
        Unit *u;
        int r = 0;

        assert(m);
        assert(dev);

        r = sd_device_get_devname(dev, &dn);
        if (r < 0)
                return 0;

        r = unit_name_from_path(dn, ".swap", &e);
        if (r < 0)
                return r;

        u = manager_get_unit(m, e);
        if (u)
                r = swap_set_devnode(SWAP(u), dn);

        FOREACH_DEVICE_DEVLINK(dev, devlink) {
                _cleanup_free_ char *n = NULL;
                int q;

                q = unit_name_from_path(devlink, ".swap", &n);
                if (q < 0)
                        return q;

                u = manager_get_unit(m, n);
                if (u) {
                        q = swap_set_devnode(SWAP(u), dn);
                        if (q < 0)
                                r = q;
                }
        }

        return r;
}

int swap_process_device_remove(Manager *m, sd_device *dev) {
        const char *dn;
        int r = 0;
        Swap *s;

        r = sd_device_get_devname(dev, &dn);
        if (r < 0)
                return 0;

        while ((s = hashmap_get(m->swaps_by_devnode, dn))) {
                int q;

                q = swap_set_devnode(s, NULL);
                if (q < 0)
                        r = q;
        }

        return r;
}

static void swap_reset_failed(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);

        if (s->state == SWAP_FAILED)
                swap_set_state(s, SWAP_DEAD);

        s->result = SWAP_SUCCESS;
}

static int swap_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
        return unit_kill_common(u, who, signo, -1, SWAP(u)->control_pid, error);
}

static int swap_get_timeout(Unit *u, usec_t *timeout) {
        Swap *s = SWAP(u);
        usec_t t;
        int r;

        if (!s->timer_event_source)
                return 0;

        r = sd_event_source_get_time(s->timer_event_source, &t);
        if (r < 0)
                return r;
        if (t == USEC_INFINITY)
                return 0;

        *timeout = t;
        return 1;
}

static bool swap_supported(void) {
        static int supported = -1;

        /* If swap support is not available in the kernel, or we are
         * running in a container we don't support swap units, and any
         * attempts to starting one should fail immediately. */

        if (supported < 0)
                supported =
                        access("/proc/swaps", F_OK) >= 0 &&
                        detect_container() <= 0;

        return supported;
}

static int swap_control_pid(Unit *u) {
        Swap *s = SWAP(u);

        assert(s);

        return s->control_pid;
}

static const char* const swap_exec_command_table[_SWAP_EXEC_COMMAND_MAX] = {
        [SWAP_EXEC_ACTIVATE] = "ExecActivate",
        [SWAP_EXEC_DEACTIVATE] = "ExecDeactivate",
};

DEFINE_STRING_TABLE_LOOKUP(swap_exec_command, SwapExecCommand);

static const char* const swap_result_table[_SWAP_RESULT_MAX] = {
        [SWAP_SUCCESS] = "success",
        [SWAP_FAILURE_RESOURCES] = "resources",
        [SWAP_FAILURE_TIMEOUT] = "timeout",
        [SWAP_FAILURE_EXIT_CODE] = "exit-code",
        [SWAP_FAILURE_SIGNAL] = "signal",
        [SWAP_FAILURE_CORE_DUMP] = "core-dump",
        [SWAP_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
};

DEFINE_STRING_TABLE_LOOKUP(swap_result, SwapResult);

const UnitVTable swap_vtable = {
        .object_size = sizeof(Swap),
        .exec_context_offset = offsetof(Swap, exec_context),
        .cgroup_context_offset = offsetof(Swap, cgroup_context),
        .kill_context_offset = offsetof(Swap, kill_context),
        .exec_runtime_offset = offsetof(Swap, exec_runtime),
        .dynamic_creds_offset = offsetof(Swap, dynamic_creds),

        .sections =
                "Unit\0"
                "Swap\0"
                "Install\0",
        .private_section = "Swap",

        .init = swap_init,
        .load = swap_load,
        .done = swap_done,

        .coldplug = swap_coldplug,

        .dump = swap_dump,

        .start = swap_start,
        .stop = swap_stop,

        .kill = swap_kill,

        .get_timeout = swap_get_timeout,

        .serialize = swap_serialize,
        .deserialize_item = swap_deserialize_item,

        .active_state = swap_active_state,
        .sub_state_to_string = swap_sub_state_to_string,

        .may_gc = swap_may_gc,

        .sigchld_event = swap_sigchld_event,

        .reset_failed = swap_reset_failed,

        .control_pid = swap_control_pid,

        .bus_vtable = bus_swap_vtable,
        .bus_set_property = bus_swap_set_property,
        .bus_commit_properties = bus_swap_commit_properties,

        .following = swap_following,
        .following_set = swap_following_set,

        .enumerate = swap_enumerate,
        .shutdown = swap_shutdown,
        .supported = swap_supported,

        .status_message_formats = {
                .starting_stopping = {
                        [0] = "Activating swap %s...",
                        [1] = "Deactivating swap %s...",
                },
                .finished_start_job = {
                        [JOB_DONE]       = "Activated swap %s.",
                        [JOB_FAILED]     = "Failed to activate swap %s.",
                        [JOB_TIMEOUT]    = "Timed out activating swap %s.",
                },
                .finished_stop_job = {
                        [JOB_DONE]       = "Deactivated swap %s.",
                        [JOB_FAILED]     = "Failed deactivating swap %s.",
                        [JOB_TIMEOUT]    = "Timed out deactivating swap %s.",
                },
        },
};