summaryrefslogtreecommitdiff
path: root/src/gpt-auto-generator/gpt-auto-generator.c
blob: a1bad9fcbee96c4585c161ffd59b491d503676ff (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
/*-*- 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 <blkid/blkid.h>
#include <stdlib.h>
#include <sys/statfs.h>
#include <unistd.h>

#include "libudev.h"
#include "sd-id128.h"

#include "alloc-util.h"
#include "blkid-util.h"
#include "btrfs-util.h"
#include "dirent-util.h"
#include "efivars.h"
#include "fd-util.h"
#include "fileio.h"
#include "fstab-util.h"
#include "generator.h"
#include "gpt.h"
#include "missing.h"
#include "mkdir.h"
#include "mount-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "proc-cmdline.h"
#include "special.h"
#include "stat-util.h"
#include "string-util.h"
#include "udev-util.h"
#include "unit-name.h"
#include "util.h"
#include "virt.h"

static const char *arg_dest = "/tmp";
static bool arg_enabled = true;
static bool arg_root_enabled = true;
static bool arg_root_rw = false;

static int add_cryptsetup(const char *id, const char *what, bool rw, char **device) {
        _cleanup_free_ char *e = NULL, *n = NULL, *p = NULL, *d = NULL, *to = NULL;
        _cleanup_fclose_ FILE *f = NULL;
        char *from, *ret;
        int r;

        assert(id);
        assert(what);
        assert(device);

        r = unit_name_from_path(what, ".device", &d);
        if (r < 0)
                return log_error_errno(r, "Failed to generate unit name: %m");

        e = unit_name_escape(id);
        if (!e)
                return log_oom();

        r = unit_name_build("systemd-cryptsetup", e, ".service", &n);
        if (r < 0)
                return log_error_errno(r, "Failed to generate unit name: %m");

        p = strjoin(arg_dest, "/", n, NULL);
        if (!p)
                return log_oom();

        f = fopen(p, "wxe");
        if (!f)
                return log_error_errno(errno, "Failed to create unit file %s: %m", p);

        fprintf(f,
                "# Automatically generated by systemd-gpt-auto-generator\n\n"
                "[Unit]\n"
                "Description=Cryptography Setup for %%I\n"
                "Documentation=man:systemd-gpt-auto-generator(8) man:systemd-cryptsetup@.service(8)\n"
                "DefaultDependencies=no\n"
                "Conflicts=umount.target\n"
                "BindsTo=dev-mapper-%%i.device %s\n"
                "Before=umount.target cryptsetup.target\n"
                "After=%s\n"
                "IgnoreOnIsolate=true\n"
                "[Service]\n"
                "Type=oneshot\n"
                "RemainAfterExit=yes\n"
                "TimeoutSec=0\n" /* the binary handles timeouts anyway */
                "ExecStart=" SYSTEMD_CRYPTSETUP_PATH " attach '%s' '%s' '' '%s'\n"
                "ExecStop=" SYSTEMD_CRYPTSETUP_PATH " detach '%s'\n",
                d, d,
                id, what, rw ? "" : "read-only",
                id);

        r = fflush_and_check(f);
        if (r < 0)
                return log_error_errno(r, "Failed to write file %s: %m", p);

        from = strjoina("../", n);

        to = strjoin(arg_dest, "/", d, ".wants/", n, NULL);
        if (!to)
                return log_oom();

        mkdir_parents_label(to, 0755);
        if (symlink(from, to) < 0)
                return log_error_errno(errno, "Failed to create symlink %s: %m", to);

        free(to);
        to = strjoin(arg_dest, "/cryptsetup.target.requires/", n, NULL);
        if (!to)
                return log_oom();

        mkdir_parents_label(to, 0755);
        if (symlink(from, to) < 0)
                return log_error_errno(errno, "Failed to create symlink %s: %m", to);

        free(to);
        to = strjoin(arg_dest, "/dev-mapper-", e, ".device.requires/", n, NULL);
        if (!to)
                return log_oom();

        mkdir_parents_label(to, 0755);
        if (symlink(from, to) < 0)
                return log_error_errno(errno, "Failed to create symlink %s: %m", to);

        free(p);
        p = strjoin(arg_dest, "/dev-mapper-", e, ".device.d/50-job-timeout-sec-0.conf", NULL);
        if (!p)
                return log_oom();

        mkdir_parents_label(p, 0755);
        r = write_string_file(p,
                        "# Automatically generated by systemd-gpt-auto-generator\n\n"
                        "[Unit]\n"
                        "JobTimeoutSec=0\n",
                        WRITE_STRING_FILE_CREATE); /* the binary handles timeouts anyway */
        if (r < 0)
                return log_error_errno(r, "Failed to write device drop-in: %m");

        ret = strappend("/dev/mapper/", id);
        if (!ret)
                return log_oom();

        *device = ret;
        return 0;
}

static int add_mount(
                const char *id,
                const char *what,
                const char *where,
                const char *fstype,
                bool rw,
                const char *options,
                const char *description,
                const char *post) {

        _cleanup_free_ char *unit = NULL, *lnk = NULL, *crypto_what = NULL, *p = NULL;
        _cleanup_fclose_ FILE *f = NULL;
        int r;

        assert(id);
        assert(what);
        assert(where);
        assert(description);

        log_debug("Adding %s: %s %s", where, what, strna(fstype));

        if (streq_ptr(fstype, "crypto_LUKS")) {

                r = add_cryptsetup(id, what, rw, &crypto_what);
                if (r < 0)
                        return r;

                what = crypto_what;
                fstype = NULL;
        }

        r = unit_name_from_path(where, ".mount", &unit);
        if (r < 0)
                return log_error_errno(r, "Failed to generate unit name: %m");

        p = strjoin(arg_dest, "/", unit, NULL);
        if (!p)
                return log_oom();

        f = fopen(p, "wxe");
        if (!f)
                return log_error_errno(errno, "Failed to create unit file %s: %m", unit);

        fprintf(f,
                "# Automatically generated by systemd-gpt-auto-generator\n\n"
                "[Unit]\n"
                "Description=%s\n"
                "Documentation=man:systemd-gpt-auto-generator(8)\n",
                description);

        if (post)
                fprintf(f, "Before=%s\n", post);

        r = generator_write_fsck_deps(f, arg_dest, what, where, fstype);
        if (r < 0)
                return r;

        fprintf(f,
                "\n"
                "[Mount]\n"
                "What=%s\n"
                "Where=%s\n",
                what, where);

        if (fstype)
                fprintf(f, "Type=%s\n", fstype);

        if (options)
                fprintf(f, "Options=%s,%s\n", options, rw ? "rw" : "ro");
        else
                fprintf(f, "Options=%s\n", rw ? "rw" : "ro");

        r = fflush_and_check(f);
        if (r < 0)
                return log_error_errno(r, "Failed to write unit file %s: %m", p);

        if (post) {
                lnk = strjoin(arg_dest, "/", post, ".requires/", unit, NULL);
                if (!lnk)
                        return log_oom();

                mkdir_parents_label(lnk, 0755);
                if (symlink(p, lnk) < 0)
                        return log_error_errno(errno, "Failed to create symlink %s: %m", lnk);
        }

        return 0;
}

static bool path_is_busy(const char *where) {
        int r;

        /* already a mountpoint; generators run during reload */
        r = path_is_mount_point(where, AT_SYMLINK_FOLLOW);
        if (r > 0)
                return false;

        /* the directory might not exist on a stateless system */
        if (r == -ENOENT)
                return false;

        if (r < 0)
                return true;

        /* not a mountpoint but it contains files */
        if (dir_is_empty(where) <= 0)
                return true;

        return false;
}

static int probe_and_add_mount(
                const char *id,
                const char *what,
                const char *where,
                bool rw,
                const char *description,
                const char *post) {

        _cleanup_blkid_free_probe_ blkid_probe b = NULL;
        const char *fstype = NULL;
        int r;

        assert(id);
        assert(what);
        assert(where);
        assert(description);

        if (path_is_busy(where)) {
                log_debug("%s already populated, ignoring.", where);
                return 0;
        }

        /* Let's check the partition type here, so that we know
         * whether to do LUKS magic. */

        errno = 0;
        b = blkid_new_probe_from_filename(what);
        if (!b) {
                if (errno == 0)
                        return log_oom();
                return log_error_errno(errno, "Failed to allocate prober: %m");
        }

        blkid_probe_enable_superblocks(b, 1);
        blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE);

        errno = 0;
        r = blkid_do_safeprobe(b);
        if (r == -2 || r == 1) /* no result or uncertain */
                return 0;
        else if (r != 0)
                return log_error_errno(errno ?: EIO, "Failed to probe %s: %m", what);

        /* add_mount is OK with fstype being NULL. */
        (void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);

        return add_mount(
                        id,
                        what,
                        where,
                        fstype,
                        rw,
                        NULL,
                        description,
                        post);
}

static int add_swap(const char *path) {
        _cleanup_free_ char *name = NULL, *unit = NULL, *lnk = NULL;
        _cleanup_fclose_ FILE *f = NULL;
        int r;

        assert(path);

        log_debug("Adding swap: %s", path);

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

        unit = strjoin(arg_dest, "/", name, NULL);
        if (!unit)
                return log_oom();

        f = fopen(unit, "wxe");
        if (!f)
                return log_error_errno(errno, "Failed to create unit file %s: %m", unit);

        fprintf(f,
                "# Automatically generated by systemd-gpt-auto-generator\n\n"
                "[Unit]\n"
                "Description=Swap Partition\n"
                "Documentation=man:systemd-gpt-auto-generator(8)\n\n"
                "[Swap]\n"
                "What=%s\n",
                path);

        r = fflush_and_check(f);
        if (r < 0)
                return log_error_errno(r, "Failed to write unit file %s: %m", unit);

        lnk = strjoin(arg_dest, "/" SPECIAL_SWAP_TARGET ".wants/", name, NULL);
        if (!lnk)
                return log_oom();

        mkdir_parents_label(lnk, 0755);
        if (symlink(unit, lnk) < 0)
                return log_error_errno(errno, "Failed to create symlink %s: %m", lnk);

        return 0;
}

#ifdef ENABLE_EFI
static int add_automount(
                const char *id,
                const char *what,
                const char *where,
                const char *fstype,
                bool rw,
                const char *options,
                const char *description,
                usec_t timeout) {

        _cleanup_free_ char *unit = NULL, *lnk = NULL;
        _cleanup_free_ char *opt, *p = NULL;
        _cleanup_fclose_ FILE *f = NULL;
        int r;

        assert(id);
        assert(where);
        assert(description);

        if (options)
                opt = strjoin(options, ",noauto", NULL);
        else
                opt = strdup("noauto");
        if (!opt)
                return log_oom();

        r = add_mount(id,
                      what,
                      where,
                      fstype,
                      rw,
                      opt,
                      description,
                      NULL);
        if (r < 0)
                return r;

        r = unit_name_from_path(where, ".automount", &unit);
        if (r < 0)
                return log_error_errno(r, "Failed to generate unit name: %m");

        p = strjoin(arg_dest, "/", unit, NULL);
        if (!p)
                return log_oom();

        f = fopen(p, "wxe");
        if (!f)
                return log_error_errno(errno, "Failed to create unit file %s: %m", unit);

        fprintf(f,
                "# Automatically generated by systemd-gpt-auto-generator\n\n"
                "[Unit]\n"
                "Description=%s\n"
                "Documentation=man:systemd-gpt-auto-generator(8)\n"
                "[Automount]\n"
                "Where=%s\n"
                "TimeoutIdleSec=%lld\n",
                description,
                where,
                (unsigned long long)timeout / USEC_PER_SEC);

        r = fflush_and_check(f);
        if (r < 0)
                return log_error_errno(r, "Failed to write unit file %s: %m", p);

        lnk = strjoin(arg_dest, "/" SPECIAL_LOCAL_FS_TARGET ".wants/", unit, NULL);
        if (!lnk)
                return log_oom();
        mkdir_parents_label(lnk, 0755);

        if (symlink(p, lnk) < 0)
                return log_error_errno(errno, "Failed to create symlink %s: %m", lnk);

        return 0;
}

static int add_boot(const char *what) {
        _cleanup_blkid_free_probe_ blkid_probe b = NULL;
        const char *fstype = NULL, *uuid = NULL;
        sd_id128_t id, type_id;
        int r;

        assert(what);

        if (!is_efi_boot()) {
                log_debug("Not an EFI boot, ignoring /boot.");
                return 0;
        }

        if (in_initrd()) {
                log_debug("In initrd, ignoring /boot.");
                return 0;
        }

        if (detect_container() > 0) {
                log_debug("In a container, ignoring /boot.");
                return 0;
        }

        /* We create an .automount which is not overridden by the .mount from the fstab generator. */
        if (fstab_is_mount_point("/boot")) {
                log_debug("/boot specified in fstab, ignoring.");
                return 0;
        }

        if (path_is_busy("/boot")) {
                log_debug("/boot already populated, ignoring.");
                return 0;
        }

        r = efi_loader_get_device_part_uuid(&id);
        if (r == -ENOENT) {
                log_debug("EFI loader partition unknown.");
                return 0;
        }

        if (r < 0) {
                log_error_errno(r, "Failed to read ESP partition UUID: %m");
                return r;
        }

        errno = 0;
        b = blkid_new_probe_from_filename(what);
        if (!b) {
                if (errno == 0)
                        return log_oom();
                return log_error_errno(errno, "Failed to allocate prober: %m");
        }

        blkid_probe_enable_partitions(b, 1);
        blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);

        errno = 0;
        r = blkid_do_safeprobe(b);
        if (r == -2 || r == 1) /* no result or uncertain */
                return 0;
        else if (r != 0)
                return log_error_errno(errno ?: EIO, "Failed to probe %s: %m", what);

        (void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
        if (!streq(fstype, "vfat")) {
                log_debug("Partition for /boot is not a FAT filesystem, ignoring.");
                return 0;
        }

        r = blkid_probe_lookup_value(b, "PART_ENTRY_UUID", &uuid, NULL);
        if (r != 0) {
                log_debug_errno(r, "Partition for /boot does not have a UUID, ignoring. %m");
                return 0;
        }

        if (sd_id128_from_string(uuid, &type_id) < 0) {
                log_debug("Partition for /boot does not have a valid UUID, ignoring.");
                return 0;
        }

        if (!sd_id128_equal(type_id, id)) {
                log_debug("Partition for /boot does not appear to be the partition we are booted from.");
                return 0;
        }

        r = add_automount("boot",
                       what,
                       "/boot",
                       "vfat",
                       true,
                       "umask=0077",
                       "EFI System Partition Automount",
                       120 * USEC_PER_SEC);

        return r;
}
#else
static int add_boot(const char *what) {
        return 0;
}
#endif

static int enumerate_partitions(dev_t devnum) {

        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
        _cleanup_udev_device_unref_ struct udev_device *d = NULL;
        _cleanup_blkid_free_probe_ blkid_probe b = NULL;
        _cleanup_udev_unref_ struct udev *udev = NULL;
        _cleanup_free_ char *boot = NULL, *home = NULL, *srv = NULL;
        struct udev_list_entry *first, *item;
        struct udev_device *parent = NULL;
        const char *name, *node, *pttype, *devtype;
        int boot_nr = -1, home_nr = -1, srv_nr = -1;
        bool home_rw = true, srv_rw = true;
        blkid_partlist pl;
        int r, k;
        dev_t pn;

        udev = udev_new();
        if (!udev)
                return log_oom();

        d = udev_device_new_from_devnum(udev, 'b', devnum);
        if (!d)
                return log_oom();

        name = udev_device_get_devnode(d);
        if (!name)
                name = udev_device_get_syspath(d);
        if (!name) {
                log_debug("Device %u:%u does not have a name, ignoring.",
                          major(devnum), minor(devnum));
                return 0;
        }

        parent = udev_device_get_parent(d);
        if (!parent) {
                log_debug("%s: not a partitioned device, ignoring.", name);
                return 0;
        }

        /* Does it have a devtype? */
        devtype = udev_device_get_devtype(parent);
        if (!devtype) {
                log_debug("%s: parent doesn't have a device type, ignoring.", name);
                return 0;
        }

        /* Is this a disk or a partition? We only care for disks... */
        if (!streq(devtype, "disk")) {
                log_debug("%s: parent isn't a raw disk, ignoring.", name);
                return 0;
        }

        /* Does it have a device node? */
        node = udev_device_get_devnode(parent);
        if (!node) {
                log_debug("%s: parent device does not have device node, ignoring.", name);
                return 0;
        }

        log_debug("%s: root device %s.", name, node);

        pn = udev_device_get_devnum(parent);
        if (major(pn) == 0)
                return 0;

        errno = 0;
        b = blkid_new_probe_from_filename(node);
        if (!b) {
                if (errno == 0)
                        return log_oom();

                return log_error_errno(errno, "%s: failed to allocate prober: %m", node);
        }

        blkid_probe_enable_partitions(b, 1);
        blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);

        errno = 0;
        r = blkid_do_safeprobe(b);
        if (r == 1)
                return 0; /* no results */
        else if (r == -2) {
                log_warning("%s: probe gave ambiguous results, ignoring.", node);
                return 0;
        } else if (r != 0)
                return log_error_errno(errno ?: EIO, "%s: failed to probe: %m", node);

        errno = 0;
        r = blkid_probe_lookup_value(b, "PTTYPE", &pttype, NULL);
        if (r != 0) {
                if (errno == 0)
                        return 0; /* No partition table found. */

                return log_error_errno(errno, "%s: failed to determine partition table type: %m", node);
        }

        /* We only do this all for GPT... */
        if (!streq_ptr(pttype, "gpt")) {
                log_debug("%s: not a GPT partition table, ignoring.", node);
                return 0;
        }

        errno = 0;
        pl = blkid_probe_get_partitions(b);
        if (!pl) {
                if (errno == 0)
                        return log_oom();

                return log_error_errno(errno, "%s: failed to list partitions: %m", node);
        }

        e = udev_enumerate_new(udev);
        if (!e)
                return log_oom();

        r = udev_enumerate_add_match_parent(e, parent);
        if (r < 0)
                return log_oom();

        r = udev_enumerate_add_match_subsystem(e, "block");
        if (r < 0)
                return log_oom();

        r = udev_enumerate_scan_devices(e);
        if (r < 0)
                return log_error_errno(r, "%s: failed to enumerate partitions: %m", node);

        first = udev_enumerate_get_list_entry(e);
        udev_list_entry_foreach(item, first) {
                _cleanup_udev_device_unref_ struct udev_device *q;
                unsigned long long flags;
                const char *stype, *subnode;
                sd_id128_t type_id;
                blkid_partition pp;
                dev_t qn;
                int nr;

                q = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
                if (!q)
                        continue;

                qn = udev_device_get_devnum(q);
                if (major(qn) == 0)
                        continue;

                if (qn == devnum)
                        continue;

                if (qn == pn)
                        continue;

                subnode = udev_device_get_devnode(q);
                if (!subnode)
                        continue;

                pp = blkid_partlist_devno_to_partition(pl, qn);
                if (!pp)
                        continue;

                nr = blkid_partition_get_partno(pp);
                if (nr < 0)
                        continue;

                stype = blkid_partition_get_type_string(pp);
                if (!stype)
                        continue;

                if (sd_id128_from_string(stype, &type_id) < 0)
                        continue;

                flags = blkid_partition_get_flags(pp);

                if (sd_id128_equal(type_id, GPT_SWAP)) {

                        if (flags & GPT_FLAG_NO_AUTO)
                                continue;

                        if (flags & GPT_FLAG_READ_ONLY) {
                                log_debug("%s marked as read-only swap partition, which is bogus. Ignoring.", subnode);
                                continue;
                        }

                        k = add_swap(subnode);
                        if (k < 0)
                                r = k;

                } else if (sd_id128_equal(type_id, GPT_ESP)) {

                        /* We only care for the first /boot partition */
                        if (boot && nr >= boot_nr)
                                continue;

                        /* Note that we do not honour the "no-auto"
                         * flag for the ESP, as it is often unset, to
                         * hide it from Windows. */

                        boot_nr = nr;

                        r = free_and_strdup(&boot, subnode);
                        if (r < 0)
                                return log_oom();

                } else if (sd_id128_equal(type_id, GPT_HOME)) {

                        if (flags & GPT_FLAG_NO_AUTO)
                                continue;

                        /* We only care for the first /home partition */
                        if (home && nr >= home_nr)
                                continue;

                        home_nr = nr;
                        home_rw = !(flags & GPT_FLAG_READ_ONLY),

                        r = free_and_strdup(&home, subnode);
                        if (r < 0)
                                return log_oom();

                } else if (sd_id128_equal(type_id, GPT_SRV)) {

                        if (flags & GPT_FLAG_NO_AUTO)
                                continue;

                        /* We only care for the first /srv partition */
                        if (srv && nr >= srv_nr)
                                continue;

                        srv_nr = nr;
                        srv_rw = !(flags & GPT_FLAG_READ_ONLY),

                        r = free_and_strdup(&srv, subnode);
                        if (r < 0)
                                return log_oom();
                }
        }

        if (boot) {
                k = add_boot(boot);
                if (k < 0)
                        r = k;
        }

        if (home) {
                k = probe_and_add_mount("home", home, "/home", home_rw, "Home Partition", SPECIAL_LOCAL_FS_TARGET);
                if (k < 0)
                        r = k;
        }

        if (srv) {
                k = probe_and_add_mount("srv", srv, "/srv", srv_rw, "Server Data Partition", SPECIAL_LOCAL_FS_TARGET);
                if (k < 0)
                        r = k;
        }

        return r;
}

static int get_block_device(const char *path, dev_t *dev) {
        struct stat st;
        struct statfs sfs;

        assert(path);
        assert(dev);

        /* Get's the block device directly backing a file system. If
         * the block device is encrypted, returns the device mapper
         * block device. */

        if (lstat(path, &st))
                return -errno;

        if (major(st.st_dev) != 0) {
                *dev = st.st_dev;
                return 1;
        }

        if (statfs(path, &sfs) < 0)
                return -errno;

        if (F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC))
                return btrfs_get_block_device(path, dev);

        return 0;
}

static int get_block_device_harder(const char *path, dev_t *dev) {
        _cleanup_closedir_ DIR *d = NULL;
        _cleanup_free_ char *p = NULL, *t = NULL;
        struct dirent *de, *found = NULL;
        const char *q;
        unsigned maj, min;
        dev_t dt;
        int r;

        assert(path);
        assert(dev);

        /* Gets the backing block device for a file system, and
         * handles LUKS encrypted file systems, looking for its
         * immediate parent, if there is one. */

        r = get_block_device(path, &dt);
        if (r <= 0)
                return r;

        if (asprintf(&p, "/sys/dev/block/%u:%u/slaves", major(dt), minor(dt)) < 0)
                return -ENOMEM;

        d = opendir(p);
        if (!d) {
                if (errno == ENOENT)
                        goto fallback;

                return -errno;
        }

        FOREACH_DIRENT_ALL(de, d, return -errno) {

                if (STR_IN_SET(de->d_name, ".", ".."))
                        continue;

                if (!IN_SET(de->d_type, DT_LNK, DT_UNKNOWN))
                        continue;

                if (found) /* Don't try to support multiple backing block devices */
                        goto fallback;

                found = de;
        }

        if (!found)
                goto fallback;

        q = strjoina(p, "/", found->d_name, "/dev");

        r = read_one_line_file(q, &t);
        if (r == -ENOENT)
                goto fallback;
        if (r < 0)
                return r;

        if (sscanf(t, "%u:%u", &maj, &min) != 2)
                return -EINVAL;

        if (maj == 0)
                goto fallback;

        *dev = makedev(maj, min);
        return 1;

fallback:
        *dev = dt;
        return 1;
}

static int parse_proc_cmdline_item(const char *key, const char *value) {
        int r;

        assert(key);

        if (STR_IN_SET(key, "systemd.gpt_auto", "rd.systemd.gpt_auto") && value) {

                r = parse_boolean(value);
                if (r < 0)
                        log_warning("Failed to parse gpt-auto switch \"%s\". Ignoring.", value);
                else
                        arg_enabled = r;

        } else if (streq(key, "root") && value) {

                /* Disable root disk logic if there's a root= value
                 * specified (unless it happens to be "gpt-auto") */

                arg_root_enabled = streq(value, "gpt-auto");

        } else if (streq(key, "rw") && !value)
                arg_root_rw = true;
        else if (streq(key, "ro") && !value)
                arg_root_rw = false;

        return 0;
}

static int add_root_mount(void) {

#ifdef ENABLE_EFI
        int r;

        if (!is_efi_boot()) {
                log_debug("Not a EFI boot, not creating root mount.");
                return 0;
        }

        r = efi_loader_get_device_part_uuid(NULL);
        if (r == -ENOENT) {
                log_debug("EFI loader partition unknown, exiting.");
                return 0;
        } else if (r < 0)
                return log_error_errno(r, "Failed to read ESP partition UUID: %m");

        /* OK, we have an ESP partition, this is fantastic, so let's
         * wait for a root device to show up. A udev rule will create
         * the link for us under the right name. */

        return add_mount(
                        "root",
                        "/dev/gpt-auto-root",
                        in_initrd() ? "/sysroot" : "/",
                        NULL,
                        arg_root_rw,
                        NULL,
                        "Root Partition",
                        in_initrd() ? SPECIAL_INITRD_ROOT_FS_TARGET : SPECIAL_LOCAL_FS_TARGET);
#else
        return 0;
#endif
}

static int add_mounts(void) {
        dev_t devno;
        int r;

        r = get_block_device_harder("/", &devno);
        if (r < 0)
                return log_error_errno(r, "Failed to determine block device of root file system: %m");
        else if (r == 0) {
                r = get_block_device_harder("/usr", &devno);
                if (r < 0)
                        return log_error_errno(r, "Failed to determine block device of /usr file system: %m");
                else if (r == 0) {
                        log_debug("Neither root nor /usr file system are on a (single) block device.");
                        return 0;
                }
        }

        return enumerate_partitions(devno);
}

int main(int argc, char *argv[]) {
        int r = 0;

        if (argc > 1 && argc != 4) {
                log_error("This program takes three or no arguments.");
                return EXIT_FAILURE;
        }

        if (argc > 1)
                arg_dest = argv[3];

        log_set_target(LOG_TARGET_SAFE);
        log_parse_environment();
        log_open();

        umask(0022);

        if (detect_container() > 0) {
                log_debug("In a container, exiting.");
                return EXIT_SUCCESS;
        }

        r = parse_proc_cmdline(parse_proc_cmdline_item);
        if (r < 0)
                log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");

        if (!arg_enabled) {
                log_debug("Disabled, exiting.");
                return EXIT_SUCCESS;
        }

        if (arg_root_enabled)
                r = add_root_mount();

        if (!in_initrd()) {
                int k;

                k = add_mounts();
                if (k < 0)
                        r = k;
        }

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}