summaryrefslogtreecommitdiff
path: root/src/core/device.c
blob: 70fac1b8b77a63a5d6c35858007b7b3e309506c5 (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
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

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

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

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

#include <errno.h>
#include <sys/epoll.h>
#include <libudev.h>

#include "strv.h"
#include "log.h"
#include "unit-name.h"
#include "dbus-device.h"
#include "def.h"
#include "path-util.h"
#include "udev-util.h"
#include "unit.h"
#include "swap.h"
#include "device.h"

static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
        [DEVICE_DEAD] = UNIT_INACTIVE,
        [DEVICE_PLUGGED] = UNIT_ACTIVE
};

static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);

static void device_unset_sysfs(Device *d) {
        Hashmap *devices;
        Device *first;

        assert(d);

        if (!d->sysfs)
                return;

        /* Remove this unit from the chain of devices which share the
         * same sysfs path. */
        devices = UNIT(d)->manager->devices_by_sysfs;
        first = hashmap_get(devices, d->sysfs);
        LIST_REMOVE(same_sysfs, first, d);

        if (first)
                hashmap_remove_and_replace(devices, d->sysfs, first->sysfs, first);
        else
                hashmap_remove(devices, d->sysfs);

        free(d->sysfs);
        d->sysfs = NULL;
}

static void device_init(Unit *u) {
        Device *d = DEVICE(u);

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

        /* In contrast to all other unit types we timeout jobs waiting
         * for devices by default. This is because they otherwise wait
         * indefinitely for plugged in devices, something which cannot
         * happen for the other units since their operations time out
         * anyway. */
        u->job_timeout = u->manager->default_timeout_start_usec;

        u->ignore_on_isolate = true;
        u->ignore_on_snapshot = true;
}

static void device_done(Unit *u) {
        Device *d = DEVICE(u);

        assert(d);

        device_unset_sysfs(d);
}

static void device_set_state(Device *d, DeviceState state) {
        DeviceState old_state;
        assert(d);

        old_state = d->state;
        d->state = state;

        if (state != old_state)
                log_debug_unit(UNIT(d)->id,
                               "%s changed %s -> %s", UNIT(d)->id,
                               device_state_to_string(old_state),
                               device_state_to_string(state));

        unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
}

static int device_coldplug(Unit *u) {
        Device *d = DEVICE(u);

        assert(d);
        assert(d->state == DEVICE_DEAD);

        if (d->sysfs)
                device_set_state(d, DEVICE_PLUGGED);

        return 0;
}

static void device_dump(Unit *u, FILE *f, const char *prefix) {
        Device *d = DEVICE(u);

        assert(d);

        fprintf(f,
                "%sDevice State: %s\n"
                "%sSysfs Path: %s\n",
                prefix, device_state_to_string(d->state),
                prefix, strna(d->sysfs));
}

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

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

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

        return device_state_to_string(DEVICE(u)->state);
}

static int device_add_escaped_name(Unit *u, const char *dn) {
        _cleanup_free_ char *e = NULL;
        int r;

        assert(u);
        assert(dn);
        assert(dn[0] == '/');

        e = unit_name_from_path(dn, ".device");
        if (!e)
                return -ENOMEM;

        r = unit_add_name(u, e);
        if (r < 0 && r != -EEXIST)
                return r;

        return 0;
}

static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
        _cleanup_free_ char *e = NULL;
        Unit *u;

        assert(m);
        assert(dn);
        assert(dn[0] == '/');
        assert(_u);

        e = unit_name_from_path(dn, ".device");
        if (!e)
                return -ENOMEM;

        u = manager_get_unit(m, e);
        if (u) {
                *_u = u;
                return 1;
        }

        return 0;
}

static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
        const char *sysfs, *model;
        Unit *u = NULL;
        int r;
        bool delete;

        assert(m);

        sysfs = udev_device_get_syspath(dev);
        if (!sysfs)
                return 0;

        r = device_find_escape_name(m, path, &u);
        if (r < 0)
                return r;

        if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
                return -EEXIST;

        if (!u) {
                delete = true;

                u = unit_new(m, sizeof(Device));
                if (!u)
                        return log_oom();

                r = device_add_escaped_name(u, path);
                if (r < 0)
                        goto fail;

                unit_add_to_load_queue(u);
        } else
                delete = false;

        /* If this was created via some dependency and has not
         * actually been seen yet ->sysfs will not be
         * initialized. Hence initialize it if necessary. */

        if (!DEVICE(u)->sysfs) {
                Device *first;

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

                r = hashmap_ensure_allocated(&m->devices_by_sysfs, string_hash_func, string_compare_func);
                if (r < 0)
                        goto fail;

                first = hashmap_get(m->devices_by_sysfs, sysfs);
                LIST_PREPEND(same_sysfs, first, DEVICE(u));

                r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first);
                if (r < 0)
                        goto fail;
        }

        if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
            (model = udev_device_get_property_value(dev, "ID_MODEL")))
                r = unit_set_description(u, model);
        else
                r = unit_set_description(u, path);
        if (r < 0)
                goto fail;

        if (main) {
                const char *wants;

                /* The additional systemd udev properties we only
                 * interpret for the main object */

                wants = udev_device_get_property_value(dev, m->running_as == SYSTEMD_USER ? "SYSTEMD_USER_WANTS" : "SYSTEMD_WANTS");
                if (wants) {
                        char *state, *w;
                        size_t l;

                        FOREACH_WORD_QUOTED(w, l, wants, state) {
                                _cleanup_free_ char *n = NULL;
                                char e[l+1];

                                memcpy(e, w, l);
                                e[l] = 0;

                                n = unit_name_mangle(e);
                                if (!n) {
                                        r = -ENOMEM;
                                        goto fail;
                                }

                                r = unit_add_dependency_by_name(u, UNIT_WANTS, n, NULL, true);
                                if (r < 0)
                                        goto fail;
                        }
                }
        }

        /* Note that this won't dispatch the load queue, the caller
         * has to do that if needed and appropriate */

        unit_add_to_dbus_queue(u);
        return 0;

fail:
        log_warning("Failed to load device unit: %s", strerror(-r));

        if (delete && u)
                unit_free(u);

        return r;
}

static int device_process_new_device(Manager *m, struct udev_device *dev) {
        const char *sysfs, *dn, *alias;
        struct udev_list_entry *item = NULL, *first = NULL;
        int r;

        assert(m);

        /* Don't pick up devices before udev finished initialization for them */
        if (!udev_device_get_is_initialized(dev))
                return 0;

        sysfs = udev_device_get_syspath(dev);
        if (!sysfs)
                return 0;

        /* Add the main unit named after the sysfs path */
        r = device_update_unit(m, dev, sysfs, true);
        if (r < 0)
                return r;

        /* Add an additional unit for the device node */
        dn = udev_device_get_devnode(dev);
        if (dn)
                device_update_unit(m, dev, dn, false);

        /* Add additional units for all symlinks */
        first = udev_device_get_devlinks_list_entry(dev);
        udev_list_entry_foreach(item, first) {
                const char *p;
                struct stat st;

                /* Don't bother with the /dev/block links */
                p = udev_list_entry_get_name(item);

                if (path_startswith(p, "/dev/block/") ||
                    path_startswith(p, "/dev/char/"))
                        continue;

                /* Verify that the symlink in the FS actually belongs
                 * to this device. This is useful to deal with
                 * conflicting devices, e.g. when two disks want the
                 * same /dev/disk/by-label/xxx link because they have
                 * the same label. We want to make sure that the same
                 * device that won the symlink wins in systemd, so we
                 * check the device node major/minor*/
                if (stat(p, &st) >= 0)
                        if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
                            st.st_rdev != udev_device_get_devnum(dev))
                                continue;

                device_update_unit(m, dev, p, false);
        }

        /* Add additional units for all explicitly configured
         * aliases */
        alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
        if (alias) {
                char *state, *w;
                size_t l;

                FOREACH_WORD_QUOTED(w, l, alias, state) {
                        char e[l+1];

                        memcpy(e, w, l);
                        e[l] = 0;

                        if (path_is_absolute(e))
                                device_update_unit(m, dev, e, false);
                        else
                                log_warning("SYSTEMD_ALIAS for %s is not an absolute path, ignoring: %s", sysfs, e);
                }
        }

        return 0;
}

static void device_set_path_plugged(Manager *m, struct udev_device *dev) {
        const char *sysfs;
        Device *d, *l;

        assert(m);
        assert(dev);

        sysfs = udev_device_get_syspath(dev);
        if (!sysfs)
                return;

        l = hashmap_get(m->devices_by_sysfs, sysfs);
        LIST_FOREACH(same_sysfs, d, l)
                device_set_state(d, DEVICE_PLUGGED);
}

static int device_process_removed_device(Manager *m, struct udev_device *dev) {
        const char *sysfs;
        Device *d;

        assert(m);
        assert(dev);

        sysfs = udev_device_get_syspath(dev);
        if (!sysfs)
                return -ENOMEM;

        /* Remove all units of this sysfs path */
        while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
                device_unset_sysfs(d);
                device_set_state(d, DEVICE_DEAD);
        }

        return 0;
}

static bool device_is_ready(struct udev_device *dev) {
        const char *ready;

        assert(dev);

        ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
        if (!ready)
                return true;

        return parse_boolean(ready) != 0;
}

static int device_process_new_path(Manager *m, const char *path) {
        _cleanup_udev_device_unref_ struct udev_device *dev = NULL;

        assert(m);
        assert(path);

        dev = udev_device_new_from_syspath(m->udev, path);
        if (!dev)
                return log_oom();

        if (!device_is_ready(dev))
                return 0;

        return device_process_new_device(m, dev);
}

static Unit *device_following(Unit *u) {
        Device *d = DEVICE(u);
        Device *other, *first = NULL;

        assert(d);

        if (startswith(u->id, "sys-"))
                return NULL;

        /* Make everybody follow the unit that's named after the sysfs path */
        for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
                if (startswith(UNIT(other)->id, "sys-"))
                        return UNIT(other);

        for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
                if (startswith(UNIT(other)->id, "sys-"))
                        return UNIT(other);

                first = other;
        }

        return UNIT(first);
}

static int device_following_set(Unit *u, Set **_set) {
        Device *d = DEVICE(u), *other;
        Set *set;
        int r;

        assert(d);
        assert(_set);

        if (LIST_JUST_US(same_sysfs, d)) {
                *_set = NULL;
                return 0;
        }

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

        LIST_FOREACH_AFTER(same_sysfs, other, d) {
                r = set_put(set, other);
                if (r < 0)
                        goto fail;
        }

        LIST_FOREACH_BEFORE(same_sysfs, other, d) {
                r = set_put(set, other);
                if (r < 0)
                        goto fail;
        }

        *_set = set;
        return 1;

fail:
        set_free(set);
        return r;
}

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

        m->udev_event_source = sd_event_source_unref(m->udev_event_source);

        if (m->udev_monitor) {
                udev_monitor_unref(m->udev_monitor);
                m->udev_monitor = NULL;
        }

        hashmap_free(m->devices_by_sysfs);
        m->devices_by_sysfs = NULL;
}

static int device_enumerate(Manager *m) {
        _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
        struct udev_list_entry *item = NULL, *first = NULL;
        int r;

        assert(m);

        if (!m->udev_monitor) {
                m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev");
                if (!m->udev_monitor) {
                        r = -ENOMEM;
                        goto fail;
                }

                /* This will fail if we are unprivileged, but that
                 * should not matter much, as user instances won't run
                 * during boot. */
                udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);

                r = udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd");
                if (r < 0)
                        goto fail;

                r = udev_monitor_enable_receiving(m->udev_monitor);
                if (r < 0)
                        goto fail;

                r = sd_event_add_io(m->event, udev_monitor_get_fd(m->udev_monitor), EPOLLIN, device_dispatch_io, m, &m->udev_event_source);
                if (r < 0)
                        goto fail;
        }

        e = udev_enumerate_new(m->udev);
        if (!e) {
                r = -ENOMEM;
                goto fail;
        }

        r = udev_enumerate_add_match_tag(e, "systemd");
        if (r < 0)
                goto fail;

        r = udev_enumerate_scan_devices(e);
        if (r < 0)
                goto fail;

        first = udev_enumerate_get_list_entry(e);
        udev_list_entry_foreach(item, first)
                device_process_new_path(m, udev_list_entry_get_name(item));

        return 0;

fail:
        device_shutdown(m);
        return r;
}

static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
        _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
        Manager *m = userdata;
        const char *action;
        int r;

        assert(m);

        if (revents != EPOLLIN) {
                static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);

                if (!ratelimit_test(&limit))
                        log_error("Failed to get udev event: %m");
                if (!(revents & EPOLLIN))
                        return 0;
        }

        /*
         * libudev might filter-out devices which pass the bloom
         * filter, so getting NULL here is not necessarily an error.
         */
        dev = udev_monitor_receive_device(m->udev_monitor);
        if (!dev)
                return 0;

        action = udev_device_get_action(dev);
        if (!action) {
                log_error("Failed to get udev action string.");
                return 0;
        }

        if (streq(action, "remove") || !device_is_ready(dev))  {
                r = device_process_removed_device(m, dev);
                if (r < 0)
                        log_error("Failed to process device remove event: %s", strerror(-r));

                r = swap_process_removed_device(m, dev);
                if (r < 0)
                        log_error("Failed to process swap device remove event: %s", strerror(-r));

        } else {
                r = device_process_new_device(m, dev);
                if (r < 0)
                        log_error("Failed to process device new event: %s", strerror(-r));

                r = swap_process_new_device(m, dev);
                if (r < 0)
                        log_error("Failed to process swap device new event: %s", strerror(-r));

                manager_dispatch_load_queue(m);

                device_set_path_plugged(m, dev);
        }

        return 0;
}

static const char* const device_state_table[_DEVICE_STATE_MAX] = {
        [DEVICE_DEAD] = "dead",
        [DEVICE_PLUGGED] = "plugged"
};

DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);

const UnitVTable device_vtable = {
        .object_size = sizeof(Device),
        .sections =
                "Unit\0"
                "Device\0"
                "Install\0",

        .no_instances = true,

        .init = device_init,
        .done = device_done,
        .load = unit_load_fragment_and_dropin_optional,

        .coldplug = device_coldplug,

        .dump = device_dump,

        .active_state = device_active_state,
        .sub_state_to_string = device_sub_state_to_string,

        .bus_interface = "org.freedesktop.systemd1.Device",
        .bus_changing_properties = bus_device_changing_properties,
        .bus_vtable = bus_device_vtable,

        .following = device_following,
        .following_set = device_following_set,

        .enumerate = device_enumerate,
        .shutdown = device_shutdown,

        .status_message_formats = {
                .starting_stopping = {
                        [0] = "Expecting device %s...",
                },
                .finished_start_job = {
                        [JOB_DONE]       = "Found device %s.",
                        [JOB_TIMEOUT]    = "Timed out waiting for device %s.",
                },
        },
};