summaryrefslogtreecommitdiff
path: root/src/core/cgroup.c
blob: 34905892baa0e384adc63a44939e7d1a84340f02 (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
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2013 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 <fcntl.h>
#include <fnmatch.h>

#include "path-util.h"
#include "special.h"
#include "cgroup-util.h"
#include "cgroup.h"

void cgroup_context_init(CGroupContext *c) {
        assert(c);

        /* Initialize everything to the kernel defaults, assuming the
         * structure is preinitialized to 0 */

        c->cpu_shares = (unsigned long) -1;
        c->startup_cpu_shares = (unsigned long) -1;
        c->memory_limit = (uint64_t) -1;
        c->blockio_weight = (unsigned long) -1;
        c->startup_blockio_weight = (unsigned long) -1;

        c->cpu_quota_per_sec_usec = (usec_t) -1;
        c->cpu_quota_usec = (usec_t) -1;
        c->cpu_quota_period_usec = 100*USEC_PER_MSEC;
}

void cgroup_context_free_device_allow(CGroupContext *c, CGroupDeviceAllow *a) {
        assert(c);
        assert(a);

        LIST_REMOVE(device_allow, c->device_allow, a);
        free(a->path);
        free(a);
}

void cgroup_context_free_blockio_device_weight(CGroupContext *c, CGroupBlockIODeviceWeight *w) {
        assert(c);
        assert(w);

        LIST_REMOVE(device_weights, c->blockio_device_weights, w);
        free(w->path);
        free(w);
}

void cgroup_context_free_blockio_device_bandwidth(CGroupContext *c, CGroupBlockIODeviceBandwidth *b) {
        assert(c);
        assert(b);

        LIST_REMOVE(device_bandwidths, c->blockio_device_bandwidths, b);
        free(b->path);
        free(b);
}

void cgroup_context_done(CGroupContext *c) {
        assert(c);

        while (c->blockio_device_weights)
                cgroup_context_free_blockio_device_weight(c, c->blockio_device_weights);

        while (c->blockio_device_bandwidths)
                cgroup_context_free_blockio_device_bandwidth(c, c->blockio_device_bandwidths);

        while (c->device_allow)
                cgroup_context_free_device_allow(c, c->device_allow);
}

usec_t cgroup_context_get_cpu_quota_usec(CGroupContext *c) {
        assert(c);

        /* Returns the absolute CPU quota */

        if (c->cpu_quota_usec != (usec_t) -1)
                return c->cpu_quota_usec;
        else if (c->cpu_quota_per_sec_usec != (usec_t) -1)
                return c->cpu_quota_per_sec_usec*c->cpu_quota_period_usec/USEC_PER_SEC;
        else
                return (usec_t) -1;
}

usec_t cgroup_context_get_cpu_quota_per_sec_usec(CGroupContext *c) {
        assert(c);

        /* Returns the CPU quota relative to 1s */

        if (c->cpu_quota_usec != (usec_t) -1)
                return c->cpu_quota_usec*USEC_PER_SEC/c->cpu_quota_period_usec;
        else if (c->cpu_quota_per_sec_usec != (usec_t) -1)
                return c->cpu_quota_per_sec_usec;
        else
                return (usec_t) -1;
}

void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
        CGroupBlockIODeviceBandwidth *b;
        CGroupBlockIODeviceWeight *w;
        CGroupDeviceAllow *a;
        char t[FORMAT_TIMESPAN_MAX], s[FORMAT_TIMESPAN_MAX], u[FORMAT_TIMESPAN_MAX];

        assert(c);
        assert(f);

        prefix = strempty(prefix);

        fprintf(f,
                "%sCPUAccounting=%s\n"
                "%sBlockIOAccounting=%s\n"
                "%sMemoryAccounting=%s\n"
                "%sCPUShares=%lu\n"
                "%sStartupCPUShares=%lu\n"
                "%sCPUQuota=%s\n"
                "%sCPUQuotaPerSecSec=%s\n"
                "%sCPUQuotaPeriodSec=%s\n"
                "%sBlockIOWeight=%lu\n"
                "%sStartupBlockIOWeight=%lu\n"
                "%sMemoryLimit=%" PRIu64 "\n"
                "%sDevicePolicy=%s\n",
                prefix, yes_no(c->cpu_accounting),
                prefix, yes_no(c->blockio_accounting),
                prefix, yes_no(c->memory_accounting),
                prefix, c->cpu_shares,
                prefix, c->startup_cpu_shares,
                prefix, strna(format_timespan(u, sizeof(u), cgroup_context_get_cpu_quota_usec(c), 1)),
                prefix, strna(format_timespan(t, sizeof(t), cgroup_context_get_cpu_quota_per_sec_usec(c), 1)),
                prefix, strna(format_timespan(s, sizeof(s), c->cpu_quota_period_usec, 1)),
                prefix, c->blockio_weight,
                prefix, c->startup_blockio_weight,
                prefix, c->memory_limit,
                prefix, cgroup_device_policy_to_string(c->device_policy));

        LIST_FOREACH(device_allow, a, c->device_allow)
                fprintf(f,
                        "%sDeviceAllow=%s %s%s%s\n",
                        prefix,
                        a->path,
                        a->r ? "r" : "", a->w ? "w" : "", a->m ? "m" : "");

        LIST_FOREACH(device_weights, w, c->blockio_device_weights)
                fprintf(f,
                        "%sBlockIODeviceWeight=%s %lu",
                        prefix,
                        w->path,
                        w->weight);

        LIST_FOREACH(device_bandwidths, b, c->blockio_device_bandwidths) {
                char buf[FORMAT_BYTES_MAX];

                fprintf(f,
                        "%s%s=%s %s\n",
                        prefix,
                        b->read ? "BlockIOReadBandwidth" : "BlockIOWriteBandwidth",
                        b->path,
                        format_bytes(buf, sizeof(buf), b->bandwidth));
        }
}

static int lookup_blkio_device(const char *p, dev_t *dev) {
        struct stat st;
        int r;

        assert(p);
        assert(dev);

        r = stat(p, &st);
        if (r < 0) {
                log_warning("Couldn't stat device %s: %m", p);
                return -errno;
        }

        if (S_ISBLK(st.st_mode))
                *dev = st.st_rdev;
        else if (major(st.st_dev) != 0) {
                /* If this is not a device node then find the block
                 * device this file is stored on */
                *dev = st.st_dev;

                /* If this is a partition, try to get the originating
                 * block device */
                block_get_whole_disk(*dev, dev);
        } else {
                log_warning("%s is not a block device and file system block device cannot be determined or is not local.", p);
                return -ENODEV;
        }

        return 0;
}

static int whitelist_device(const char *path, const char *node, const char *acc) {
        char buf[2+DECIMAL_STR_MAX(dev_t)*2+2+4];
        struct stat st;
        int r;

        assert(path);
        assert(acc);

        if (stat(node, &st) < 0) {
                log_warning("Couldn't stat device %s", node);
                return -errno;
        }

        if (!S_ISCHR(st.st_mode) && !S_ISBLK(st.st_mode)) {
                log_warning("%s is not a device.", node);
                return -ENODEV;
        }

        sprintf(buf,
                "%c %u:%u %s",
                S_ISCHR(st.st_mode) ? 'c' : 'b',
                major(st.st_rdev), minor(st.st_rdev),
                acc);

        r = cg_set_attribute("devices", path, "devices.allow", buf);
        if (r < 0)
                log_warning("Failed to set devices.allow on %s: %s", path, strerror(-r));

        return r;
}

static int whitelist_major(const char *path, const char *name, char type, const char *acc) {
        _cleanup_fclose_ FILE *f = NULL;
        char line[LINE_MAX];
        bool good = false;
        int r;

        assert(path);
        assert(acc);
        assert(type == 'b' || type == 'c');

        f = fopen("/proc/devices", "re");
        if (!f) {
                log_warning("Cannot open /proc/devices to resolve %s (%c): %m", name, type);
                return -errno;
        }

        FOREACH_LINE(line, f, goto fail) {
                char buf[2+DECIMAL_STR_MAX(unsigned)+3+4], *p, *w;
                unsigned maj;

                truncate_nl(line);

                if (type == 'c' && streq(line, "Character devices:")) {
                        good = true;
                        continue;
                }

                if (type == 'b' && streq(line, "Block devices:")) {
                        good = true;
                        continue;
                }

                if (isempty(line)) {
                        good = false;
                        continue;
                }

                if (!good)
                        continue;

                p = strstrip(line);

                w = strpbrk(p, WHITESPACE);
                if (!w)
                        continue;
                *w = 0;

                r = safe_atou(p, &maj);
                if (r < 0)
                        continue;
                if (maj <= 0)
                        continue;

                w++;
                w += strspn(w, WHITESPACE);

                if (fnmatch(name, w, 0) != 0)
                        continue;

                sprintf(buf,
                        "%c %u:* %s",
                        type,
                        maj,
                        acc);

                r = cg_set_attribute("devices", path, "devices.allow", buf);
                if (r < 0)
                        log_warning("Failed to set devices.allow on %s: %s", path, strerror(-r));
        }

        return 0;

fail:
        log_warning("Failed to read /proc/devices: %m");
        return -errno;
}

void cgroup_context_apply(CGroupContext *c, CGroupControllerMask mask, const char *path, ManagerState state) {
        bool is_root;
        int r;

        assert(c);
        assert(path);

        if (mask == 0)
                return;

        /* Some cgroup attributes are not support on the root cgroup,
         * hence silently ignore */
        is_root = isempty(path) || path_equal(path, "/");

        if ((mask & CGROUP_CPU) && !is_root) {
                char buf[MAX(DECIMAL_STR_MAX(unsigned long), DECIMAL_STR_MAX(usec_t)) + 1];
                usec_t q;

                sprintf(buf, "%lu\n",
                        state == MANAGER_STARTING && c->startup_cpu_shares != (unsigned long) -1 ? c->startup_cpu_shares :
                        c->cpu_shares != (unsigned long) -1 ? c->cpu_shares : 1024);
                r = cg_set_attribute("cpu", path, "cpu.shares", buf);
                if (r < 0)
                        log_warning("Failed to set cpu.shares on %s: %s", path, strerror(-r));

                sprintf(buf, USEC_FMT "\n", c->cpu_quota_period_usec);
                r = cg_set_attribute("cpu", path, "cpu.cfs_period_us", buf);
                if (r < 0)
                        log_warning("Failed to set cpu.cfs_period_us on %s: %s", path, strerror(-r));

                q = cgroup_context_get_cpu_quota_usec(c);
                if (q != (usec_t) -1) {
                        sprintf(buf, USEC_FMT "\n", q);
                        r = cg_set_attribute("cpu", path, "cpu.cfs_quota_us", buf);
                } else
                        r = cg_set_attribute("cpu", path, "cpu.cfs_quota_us", "-1");
                if (r < 0)
                        log_warning("Failed to set cpu.cfs_quota_us on %s: %s", path, strerror(-r));
        }

        if (mask & CGROUP_BLKIO) {
                char buf[MAX3(DECIMAL_STR_MAX(unsigned long)+1,
                              DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(unsigned long)*1,
                              DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(uint64_t)+1)];
                CGroupBlockIODeviceWeight *w;
                CGroupBlockIODeviceBandwidth *b;

                if (!is_root) {
                        sprintf(buf, "%lu\n", state == MANAGER_STARTING && c->startup_blockio_weight != (unsigned long) -1 ? c->startup_blockio_weight :
                                c->blockio_weight != (unsigned long) -1 ? c->blockio_weight : 1000);
                        r = cg_set_attribute("blkio", path, "blkio.weight", buf);
                        if (r < 0)
                                log_warning("Failed to set blkio.weight on %s: %s", path, strerror(-r));

                        /* FIXME: no way to reset this list */
                        LIST_FOREACH(device_weights, w, c->blockio_device_weights) {
                                dev_t dev;

                                r = lookup_blkio_device(w->path, &dev);
                                if (r < 0)
                                        continue;

                                sprintf(buf, "%u:%u %lu", major(dev), minor(dev), w->weight);
                                r = cg_set_attribute("blkio", path, "blkio.weight_device", buf);
                                if (r < 0)
                                        log_error("Failed to set blkio.weight_device on %s: %s", path, strerror(-r));
                        }
                }

                /* FIXME: no way to reset this list */
                LIST_FOREACH(device_bandwidths, b, c->blockio_device_bandwidths) {
                        const char *a;
                        dev_t dev;

                        r = lookup_blkio_device(b->path, &dev);
                        if (r < 0)
                                continue;

                        a = b->read ? "blkio.throttle.read_bps_device" : "blkio.throttle.write_bps_device";

                        sprintf(buf, "%u:%u %" PRIu64 "\n", major(dev), minor(dev), b->bandwidth);
                        r = cg_set_attribute("blkio", path, a, buf);
                        if (r < 0)
                                log_error("Failed to set %s on %s: %s", a, path, strerror(-r));
                }
        }

        if (mask & CGROUP_MEMORY) {
                if (c->memory_limit != (uint64_t) -1) {
                        char buf[DECIMAL_STR_MAX(uint64_t) + 1];

                        sprintf(buf, "%" PRIu64 "\n", c->memory_limit);
                        r = cg_set_attribute("memory", path, "memory.limit_in_bytes", buf);
                } else
                        r = cg_set_attribute("memory", path, "memory.limit_in_bytes", "-1");

                if (r < 0)
                        log_error("Failed to set memory.limit_in_bytes on %s: %s", path, strerror(-r));
        }

        if ((mask & CGROUP_DEVICE) && !is_root) {
                CGroupDeviceAllow *a;

                if (c->device_allow || c->device_policy != CGROUP_AUTO)
                        r = cg_set_attribute("devices", path, "devices.deny", "a");
                else
                        r = cg_set_attribute("devices", path, "devices.allow", "a");
                if (r < 0)
                        log_warning("Failed to reset devices.list on %s: %s", path, strerror(-r));

                if (c->device_policy == CGROUP_CLOSED ||
                    (c->device_policy == CGROUP_AUTO && c->device_allow)) {
                        static const char auto_devices[] =
                                "/dev/null\0" "rwm\0"
                                "/dev/zero\0" "rwm\0"
                                "/dev/full\0" "rwm\0"
                                "/dev/random\0" "rwm\0"
                                "/dev/urandom\0" "rwm\0"
                                "/dev/tty\0" "rwm\0"
                                "/dev/pts/ptmx\0" "rw\0"; /* /dev/pts/ptmx may not be duplicated, but accessed */

                        const char *x, *y;

                        NULSTR_FOREACH_PAIR(x, y, auto_devices)
                                whitelist_device(path, x, y);

                        whitelist_major(path, "pts", 'c', "rw");
                        whitelist_major(path, "kdbus", 'c', "rw");
                        whitelist_major(path, "kdbus/*", 'c', "rw");
                }

                LIST_FOREACH(device_allow, a, c->device_allow) {
                        char acc[4];
                        unsigned k = 0;

                        if (a->r)
                                acc[k++] = 'r';
                        if (a->w)
                                acc[k++] = 'w';
                        if (a->m)
                                acc[k++] = 'm';

                        if (k == 0)
                                continue;

                        acc[k++] = 0;

                        if (startswith(a->path, "/dev/"))
                                whitelist_device(path, a->path, acc);
                        else if (startswith(a->path, "block-"))
                                whitelist_major(path, a->path + 6, 'b', acc);
                        else if (startswith(a->path, "char-"))
                                whitelist_major(path, a->path + 5, 'c', acc);
                        else
                                log_debug("Ignoring device %s while writing cgroup attribute.", a->path);
                }
        }
}

CGroupControllerMask cgroup_context_get_mask(CGroupContext *c) {
        CGroupControllerMask mask = 0;

        /* Figure out which controllers we need */

        if (c->cpu_accounting ||
            c->cpu_shares != (unsigned long) -1 ||
            c->startup_cpu_shares != (unsigned long) -1 ||
            c->cpu_quota_usec != (usec_t) -1 ||
            c->cpu_quota_per_sec_usec != (usec_t) -1)
                mask |= CGROUP_CPUACCT | CGROUP_CPU;

        if (c->blockio_accounting ||
            c->blockio_weight != (unsigned long) -1 ||
            c->startup_blockio_weight != (unsigned long) -1 ||
            c->blockio_device_weights ||
            c->blockio_device_bandwidths)
                mask |= CGROUP_BLKIO;

        if (c->memory_accounting ||
            c->memory_limit != (uint64_t) -1)
                mask |= CGROUP_MEMORY;

        if (c->device_allow || c->device_policy != CGROUP_AUTO)
                mask |= CGROUP_DEVICE;

        return mask;
}

CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
        CGroupContext *c;

        c = unit_get_cgroup_context(u);
        if (!c)
                return 0;

        return cgroup_context_get_mask(c);
}

CGroupControllerMask unit_get_members_mask(Unit *u) {
        assert(u);

        if (u->cgroup_members_mask_valid)
                return u->cgroup_members_mask;

        u->cgroup_members_mask = 0;

        if (u->type == UNIT_SLICE) {
                Unit *member;
                Iterator i;

                SET_FOREACH(member, u->dependencies[UNIT_BEFORE], i) {

                        if (member == u)
                                continue;

                        if (UNIT_DEREF(member->slice) != u)
                                continue;

                        u->cgroup_members_mask |=
                                unit_get_cgroup_mask(member) |
                                unit_get_members_mask(member);
                }
        }

        u->cgroup_members_mask_valid = true;
        return u->cgroup_members_mask;
}

CGroupControllerMask unit_get_siblings_mask(Unit *u) {
        CGroupControllerMask m;

        assert(u);

        if (UNIT_ISSET(u->slice))
                m = unit_get_members_mask(UNIT_DEREF(u->slice));
        else
                m = unit_get_cgroup_mask(u) | unit_get_members_mask(u);

        /* Sibling propagation is only relevant for weight-based
         * controllers, so let's mask out everything else */
        return m & (CGROUP_CPU|CGROUP_BLKIO|CGROUP_CPUACCT);
}

CGroupControllerMask unit_get_target_mask(Unit *u) {
        CGroupControllerMask mask;

        mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
        mask &= u->manager->cgroup_supported;

        return mask;
}

/* Recurse from a unit up through its containing slices, propagating
 * mask bits upward. A unit is also member of itself. */
void unit_update_cgroup_members_masks(Unit *u) {
        CGroupControllerMask m;
        bool more;

        assert(u);

        /* Calculate subtree mask */
        m = unit_get_cgroup_mask(u) | unit_get_members_mask(u);

        /* See if anything changed from the previous invocation. If
         * not, we're done. */
        if (u->cgroup_subtree_mask_valid && m == u->cgroup_subtree_mask)
                return;

        more =
                u->cgroup_subtree_mask_valid &&
                ((m & ~u->cgroup_subtree_mask) != 0) &&
                ((~m & u->cgroup_subtree_mask) == 0);

        u->cgroup_subtree_mask = m;
        u->cgroup_subtree_mask_valid = true;

        if (UNIT_ISSET(u->slice)) {
                Unit *s = UNIT_DEREF(u->slice);

                if (more)
                        /* There's more set now than before. We
                         * propagate the new mask to the parent's mask
                         * (not caring if it actually was valid or
                         * not). */

                        s->cgroup_members_mask |= m;

                else
                        /* There's less set now than before (or we
                         * don't know), we need to recalculate
                         * everything, so let's invalidate the
                         * parent's members mask */

                        s->cgroup_members_mask_valid = false;

                /* And now make sure that this change also hits our
                 * grandparents */
                unit_update_cgroup_members_masks(s);
        }
}

static const char *migrate_callback(CGroupControllerMask mask, void *userdata) {
        Unit *u = userdata;

        assert(mask != 0);
        assert(u);

        while (u) {
                if (u->cgroup_path &&
                    u->cgroup_realized &&
                    (u->cgroup_realized_mask & mask) == mask)
                        return u->cgroup_path;

                u = UNIT_DEREF(u->slice);
        }

        return NULL;
}

static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
        _cleanup_free_ char *path = NULL;
        int r;

        assert(u);

        path = unit_default_cgroup_path(u);
        if (!path)
                return log_oom();

        r = hashmap_put(u->manager->cgroup_unit, path, u);
        if (r < 0) {
                log_error(r == -EEXIST ? "cgroup %s exists already: %s" : "hashmap_put failed for %s: %s", path, strerror(-r));
                return r;
        }
        if (r > 0) {
                u->cgroup_path = path;
                path = NULL;
        }

        /* First, create our own group */
        r = cg_create_everywhere(u->manager->cgroup_supported, mask, u->cgroup_path);
        if (r < 0) {
                log_error("Failed to create cgroup %s: %s", u->cgroup_path, strerror(-r));
                return r;
        }

        /* Keep track that this is now realized */
        u->cgroup_realized = true;
        u->cgroup_realized_mask = mask;

        /* Then, possibly move things over */
        r = cg_migrate_everywhere(u->manager->cgroup_supported, u->cgroup_path, u->cgroup_path, migrate_callback, u);
        if (r < 0)
                log_warning("Failed to migrate cgroup from to %s: %s", u->cgroup_path, strerror(-r));

        return 0;
}

static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
        assert(u);

        return u->cgroup_realized && u->cgroup_realized_mask == mask;
}

/* Check if necessary controllers and attributes for a unit are in place.
 *
 * If so, do nothing.
 * If not, create paths, move processes over, and set attributes.
 *
 * Returns 0 on success and < 0 on failure. */
static int unit_realize_cgroup_now(Unit *u, ManagerState state) {
        CGroupControllerMask mask;
        int r;

        assert(u);

        if (u->in_cgroup_queue) {
                LIST_REMOVE(cgroup_queue, u->manager->cgroup_queue, u);
                u->in_cgroup_queue = false;
        }

        mask = unit_get_target_mask(u);

        if (unit_has_mask_realized(u, mask))
                return 0;

        /* First, realize parents */
        if (UNIT_ISSET(u->slice)) {
                r = unit_realize_cgroup_now(UNIT_DEREF(u->slice), state);
                if (r < 0)
                        return r;
        }

        /* And then do the real work */
        r = unit_create_cgroups(u, mask);
        if (r < 0)
                return r;

        /* Finally, apply the necessary attributes. */
        cgroup_context_apply(unit_get_cgroup_context(u), mask, u->cgroup_path, state);

        return 0;
}

static void unit_add_to_cgroup_queue(Unit *u) {

        if (u->in_cgroup_queue)
                return;

        LIST_PREPEND(cgroup_queue, u->manager->cgroup_queue, u);
        u->in_cgroup_queue = true;
}

unsigned manager_dispatch_cgroup_queue(Manager *m) {
        ManagerState state;
        unsigned n = 0;
        Unit *i;
        int r;

        state = manager_state(m);

        while ((i = m->cgroup_queue)) {
                assert(i->in_cgroup_queue);

                r = unit_realize_cgroup_now(i, state);
                if (r < 0)
                        log_warning("Failed to realize cgroups for queued unit %s: %s", i->id, strerror(-r));

                n++;
        }

        return n;
}

static void unit_queue_siblings(Unit *u) {
        Unit *slice;

        /* This adds the siblings of the specified unit and the
         * siblings of all parent units to the cgroup queue. (But
         * neither the specified unit itself nor the parents.) */

        while ((slice = UNIT_DEREF(u->slice))) {
                Iterator i;
                Unit *m;

                SET_FOREACH(m, slice->dependencies[UNIT_BEFORE], i) {
                        if (m == u)
                                continue;

                        /* Skip units that have a dependency on the slice
                         * but aren't actually in it. */
                        if (UNIT_DEREF(m->slice) != slice)
                                continue;

                        /* No point in doing cgroup application for units
                         * without active processes. */
                        if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(m)))
                                continue;

                        /* If the unit doesn't need any new controllers
                         * and has current ones realized, it doesn't need
                         * any changes. */
                        if (unit_has_mask_realized(m, unit_get_target_mask(m)))
                                continue;

                        unit_add_to_cgroup_queue(m);
                }

                u = slice;
        }
}

int unit_realize_cgroup(Unit *u) {
        CGroupContext *c;

        assert(u);

        c = unit_get_cgroup_context(u);
        if (!c)
                return 0;

        /* So, here's the deal: when realizing the cgroups for this
         * unit, we need to first create all parents, but there's more
         * actually: for the weight-based controllers we also need to
         * make sure that all our siblings (i.e. units that are in the
         * same slice as we are) have cgroups, too. Otherwise, things
         * would become very uneven as each of their processes would
         * get as much resources as all our group together. This call
         * will synchronously create the parent cgroups, but will
         * defer work on the siblings to the next event loop
         * iteration. */

        /* Add all sibling slices to the cgroup queue. */
        unit_queue_siblings(u);

        /* And realize this one now (and apply the values) */
        return unit_realize_cgroup_now(u, manager_state(u->manager));
}

void unit_destroy_cgroup(Unit *u) {
        int r;

        assert(u);

        if (!u->cgroup_path)
                return;

        r = cg_trim_everywhere(u->manager->cgroup_supported, u->cgroup_path, !unit_has_name(u, SPECIAL_ROOT_SLICE));
        if (r < 0)
                log_debug("Failed to destroy cgroup %s: %s", u->cgroup_path, strerror(-r));

        hashmap_remove(u->manager->cgroup_unit, u->cgroup_path);

        free(u->cgroup_path);
        u->cgroup_path = NULL;
        u->cgroup_realized = false;
        u->cgroup_realized_mask = 0;

}

pid_t unit_search_main_pid(Unit *u) {
        _cleanup_fclose_ FILE *f = NULL;
        pid_t pid = 0, npid, mypid;

        assert(u);

        if (!u->cgroup_path)
                return 0;

        if (cg_enumerate_processes(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, &f) < 0)
                return 0;

        mypid = getpid();
        while (cg_read_pid(f, &npid) > 0)  {
                pid_t ppid;

                if (npid == pid)
                        continue;

                /* Ignore processes that aren't our kids */
                if (get_parent_of_pid(npid, &ppid) >= 0 && ppid != mypid)
                        continue;

                if (pid != 0) {
                        /* Dang, there's more than one daemonized PID
                        in this group, so we don't know what process
                        is the main process. */
                        pid = 0;
                        break;
                }

                pid = npid;
        }

        return pid;
}

int manager_setup_cgroup(Manager *m) {
        _cleanup_free_ char *path = NULL;
        char *e;
        int r;

        assert(m);

        /* 1. Determine hierarchy */
        free(m->cgroup_root);
        m->cgroup_root = NULL;

        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &m->cgroup_root);
        if (r < 0) {
                log_error("Cannot determine cgroup we are running in: %s", strerror(-r));
                return r;
        }

        /* LEGACY: Already in /system.slice? If so, let's cut this
         * off. This is to support live upgrades from older systemd
         * versions where PID 1 was moved there. */
        if (m->running_as == SYSTEMD_SYSTEM) {
                e = endswith(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);
                if (!e)
                        e = endswith(m->cgroup_root, "/system");
                if (e)
                        *e = 0;
        }

        /* And make sure to store away the root value without trailing
         * slash, even for the root dir, so that we can easily prepend
         * it everywhere. */
        if (streq(m->cgroup_root, "/"))
                m->cgroup_root[0] = 0;

        /* 2. Show data */
        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, NULL, &path);
        if (r < 0) {
                log_error("Cannot find cgroup mount point: %s", strerror(-r));
                return r;
        }

        log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);

        /* 3. Install agent */
        if (m->running_as == SYSTEMD_SYSTEM) {
                r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, SYSTEMD_CGROUP_AGENT_PATH);
                if (r < 0)
                        log_warning("Failed to install release agent, ignoring: %s", strerror(-r));
                else if (r > 0)
                        log_debug("Installed release agent.");
                else
                        log_debug("Release agent already installed.");
        }

        /* 4. Make sure we are in the root cgroup */
        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, 0);
        if (r < 0) {
                log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));
                return r;
        }

        /* 5. And pin it, so that it cannot be unmounted */
        safe_close(m->pin_cgroupfs_fd);

        m->pin_cgroupfs_fd = open(path, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY|O_NONBLOCK);
        if (m->pin_cgroupfs_fd < 0) {
                log_error("Failed to open pin file: %m");
                return -errno;
        }

        /* 6. Figure out which controllers are supported */
        m->cgroup_supported = cg_mask_supported();

        /* 7.  Always enable hierarchial support if it exists... */
        cg_set_attribute("memory", "/", "memory.use_hierarchy", "1");

        return 0;
}

void manager_shutdown_cgroup(Manager *m, bool delete) {
        assert(m);

        /* We can't really delete the group, since we are in it. But
         * let's trim it. */
        if (delete && m->cgroup_root)
                cg_trim(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, false);

        m->pin_cgroupfs_fd = safe_close(m->pin_cgroupfs_fd);

        free(m->cgroup_root);
        m->cgroup_root = NULL;
}

Unit* manager_get_unit_by_cgroup(Manager *m, const char *cgroup) {
        char *p;
        Unit *u;

        assert(m);
        assert(cgroup);

        u = hashmap_get(m->cgroup_unit, cgroup);
        if (u)
                return u;

        p = strdupa(cgroup);
        for (;;) {
                char *e;

                e = strrchr(p, '/');
                if (e == p || !e)
                        return NULL;

                *e = 0;

                u = hashmap_get(m->cgroup_unit, p);
                if (u)
                        return u;
        }
}

Unit *manager_get_unit_by_pid(Manager *m, pid_t pid) {
        _cleanup_free_ char *cgroup = NULL;
        int r;

        assert(m);

        if (pid <= 1)
                return NULL;

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

        return manager_get_unit_by_cgroup(m, cgroup);
}

int manager_notify_cgroup_empty(Manager *m, const char *cgroup) {
        Unit *u;
        int r;

        assert(m);
        assert(cgroup);

        u = manager_get_unit_by_cgroup(m, cgroup);
        if (u) {
                r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);
                if (r > 0) {
                        if (UNIT_VTABLE(u)->notify_cgroup_empty)
                                UNIT_VTABLE(u)->notify_cgroup_empty(u);

                        unit_add_to_gc_queue(u);
                }
        }

        return 0;
}

static const char* const cgroup_device_policy_table[_CGROUP_DEVICE_POLICY_MAX] = {
        [CGROUP_AUTO] = "auto",
        [CGROUP_CLOSED] = "closed",
        [CGROUP_STRICT] = "strict",
};

DEFINE_STRING_TABLE_LOOKUP(cgroup_device_policy, CGroupDevicePolicy);