src/core/device.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <sys/epoll.h>
  24 #include <libudev.h>
  25
  26 #include "strv.h"
  27 #include "log.h"
  28 #include "unit-name.h"
  29 #include "dbus-device.h"
  30 #include "def.h"
  31 #include "path-util.h"
  32 #include "udev-util.h"
  33 #include "unit.h"
  34 #include "swap.h"
  35 #include "device.h"
  36
  37 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  38         [DEVICE_DEAD] = UNIT_INACTIVE,
  39         [DEVICE_PLUGGED] = UNIT_ACTIVE
  40 };
  41
  42 static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
  43
  44 static void device_unset_sysfs(Device *d) {
  45         Hashmap *devices;
  46         Device *first;
  47
  48         assert(d);
  49
  50         if (!d->sysfs)
  51                 return;
  52
  53         /* Remove this unit from the chain of devices which share the
  54          * same sysfs path. */
  55         devices = UNIT(d)->manager->devices_by_sysfs;
  56         first = hashmap_get(devices, d->sysfs);
  57         LIST_REMOVE(same_sysfs, first, d);
  58
  59         if (first)
  60                 hashmap_remove_and_replace(devices, d->sysfs, first->sysfs, first);
  61         else
  62                 hashmap_remove(devices, d->sysfs);
  63
  64         free(d->sysfs);
  65         d->sysfs = NULL;
  66 }
  67
  68 static void device_init(Unit *u) {
  69         Device *d = DEVICE(u);
  70
  71         assert(d);
  72         assert(UNIT(d)->load_state == UNIT_STUB);
  73
  74         /* In contrast to all other unit types we timeout jobs waiting
  75          * for devices by default. This is because they otherwise wait
  76          * indefinitely for plugged in devices, something which cannot
  77          * happen for the other units since their operations time out
  78          * anyway. */
  79         u->job_timeout = u->manager->default_timeout_start_usec;
  80
  81         u->ignore_on_isolate = true;
  82         u->ignore_on_snapshot = true;
  83 }
  84
  85 static void device_done(Unit *u) {
  86         Device *d = DEVICE(u);
  87
  88         assert(d);
  89
  90         device_unset_sysfs(d);
  91 }
  92
  93 static void device_set_state(Device *d, DeviceState state) {
  94         DeviceState old_state;
  95         assert(d);
  96
  97         old_state = d->state;
  98         d->state = state;
  99
 100         if (state != old_state)
 101                 log_debug_unit(UNIT(d)->id,
 102                                "%s changed %s -> %s", UNIT(d)->id,
 103                                device_state_to_string(old_state),
 104                                device_state_to_string(state));
 105
 106         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
 107 }
 108
 109 static int device_coldplug(Unit *u) {
 110         Device *d = DEVICE(u);
 111
 112         assert(d);
 113         assert(d->state == DEVICE_DEAD);
 114
 115         if (d->sysfs)
 116                 device_set_state(d, DEVICE_PLUGGED);
 117
 118         return 0;
 119 }
 120
 121 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 122         Device *d = DEVICE(u);
 123
 124         assert(d);
 125
 126         fprintf(f,
 127                 "%sDevice State: %s\n"
 128                 "%sSysfs Path: %s\n",
 129                 prefix, device_state_to_string(d->state),
 130                 prefix, strna(d->sysfs));
 131 }
 132
 133 _pure_ static UnitActiveState device_active_state(Unit *u) {
 134         assert(u);
 135
 136         return state_translation_table[DEVICE(u)->state];
 137 }
 138
 139 _pure_ static const char *device_sub_state_to_string(Unit *u) {
 140         assert(u);
 141
 142         return device_state_to_string(DEVICE(u)->state);
 143 }
 144
 145 static int device_add_escaped_name(Unit *u, const char *dn) {
 146         _cleanup_free_ char *e = NULL;
 147         int r;
 148
 149         assert(u);
 150         assert(dn);
 151         assert(dn[0] == '/');
 152
 153         e = unit_name_from_path(dn, ".device");
 154         if (!e)
 155                 return -ENOMEM;
 156
 157         r = unit_add_name(u, e);
 158         if (r < 0 && r != -EEXIST)
 159                 return r;
 160
 161         return 0;
 162 }
 163
 164 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 165         _cleanup_free_ char *e = NULL;
 166         Unit *u;
 167
 168         assert(m);
 169         assert(dn);
 170         assert(dn[0] == '/');
 171         assert(_u);
 172
 173         e = unit_name_from_path(dn, ".device");
 174         if (!e)
 175                 return -ENOMEM;
 176
 177         u = manager_get_unit(m, e);
 178         if (u) {
 179                 *_u = u;
 180                 return 1;
 181         }
 182
 183         return 0;
 184 }
 185
 186 static int device_make_description(Unit *u, struct udev_device *dev, const char *path) {
 187         const char *model;
 188
 189         assert(u);
 190         assert(dev);
 191         assert(path);
 192
 193         model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE");
 194         if (!model)
 195                 model = udev_device_get_property_value(dev, "ID_MODEL");
 196
 197         if (model) {
 198                 const char *label;
 199
 200                 /* Try to concatenate the device model string with a label, if there is one */
 201                 label = udev_device_get_property_value(dev, "ID_FS_LABEL");
 202                 if (!label)
 203                         label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NAME");
 204                 if (!label)
 205                         label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NUMBER");
 206
 207                 if (label) {
 208                         _cleanup_free_ char *j;
 209
 210                         j = strjoin(model, " ", label, NULL);
 211                         if (j)
 212                                 return unit_set_description(u, j);
 213                 }
 214
 215                 return unit_set_description(u, model);
 216         }
 217
 218         return unit_set_description(u, path);
 219 }
 220
 221 static int device_add_udev_wants(Unit *u, struct udev_device *dev) {
 222         const char *wants;
 223         const char *word, *state;
 224         size_t l;
 225         int r;
 226         const char *property;
 227
 228         assert(u);
 229         assert(dev);
 230
 231         property = u->manager->running_as == SYSTEMD_USER ? "SYSTEMD_USER_WANTS" : "SYSTEMD_WANTS";
 232         wants = udev_device_get_property_value(dev, property);
 233         if (!wants)
 234                 return 0;
 235
 236         FOREACH_WORD_QUOTED(word, l, wants, state) {
 237                 _cleanup_free_ char *n = NULL;
 238                 char e[l+1];
 239
 240                 memcpy(e, word, l);
 241                 e[l] = 0;
 242
 243                 n = unit_name_mangle(e, MANGLE_NOGLOB);
 244                 if (!n)
 245                         return -ENOMEM;
 246
 247                 r = unit_add_dependency_by_name(u, UNIT_WANTS, n, NULL, true);
 248                 if (r < 0)
 249                         return r;
 250         }
 251         if (!isempty(state))
 252                 log_warning_unit(u->id, "Property %s on %s has trailing garbage, ignoring.",
 253                                  property, strna(udev_device_get_syspath(dev)));
 254
 255         return 0;
 256 }
 257
 258 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 259         const char *sysfs;
 260         Unit *u = NULL;
 261         bool delete;
 262         int r;
 263
 264         assert(m);
 265         assert(dev);
 266         assert(path);
 267
 268         sysfs = udev_device_get_syspath(dev);
 269         if (!sysfs)
 270                 return 0;
 271
 272         r = device_find_escape_name(m, path, &u);
 273         if (r < 0)
 274                 return r;
 275
 276         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 277                 return -EEXIST;
 278
 279         if (!u) {
 280                 delete = true;
 281
 282                 u = unit_new(m, sizeof(Device));
 283                 if (!u)
 284                         return log_oom();
 285
 286                 r = device_add_escaped_name(u, path);
 287                 if (r < 0)
 288                         goto fail;
 289
 290                 unit_add_to_load_queue(u);
 291         } else
 292                 delete = false;
 293
 294         /* If this was created via some dependency and has not
 295          * actually been seen yet ->sysfs will not be
 296          * initialized. Hence initialize it if necessary. */
 297
 298         if (!DEVICE(u)->sysfs) {
 299                 Device *first;
 300
 301                 DEVICE(u)->sysfs = strdup(sysfs);
 302                 if (!DEVICE(u)->sysfs) {
 303                         r = -ENOMEM;
 304                         goto fail;
 305                 }
 306
 307                 r = hashmap_ensure_allocated(&m->devices_by_sysfs, &string_hash_ops);
 308                 if (r < 0)
 309                         goto fail;
 310
 311                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 312                 LIST_PREPEND(same_sysfs, first, DEVICE(u));
 313
 314                 r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first);
 315                 if (r < 0)
 316                         goto fail;
 317         }
 318
 319         device_make_description(u, dev, path);
 320
 321         if (main) {
 322                 /* The additional systemd udev properties we only
 323                  * interpret for the main object */
 324
 325                 r = device_add_udev_wants(u, dev);
 326                 if (r < 0)
 327                         goto fail;
 328         }
 329
 330         /* Note that this won't dispatch the load queue, the caller
 331          * has to do that if needed and appropriate */
 332
 333         unit_add_to_dbus_queue(u);
 334         return 0;
 335
 336 fail:
 337         log_warning("Failed to load device unit: %s", strerror(-r));
 338
 339         if (delete && u)
 340                 unit_free(u);
 341
 342         return r;
 343 }
 344
 345 static int device_process_new_device(Manager *m, struct udev_device *dev) {
 346         const char *sysfs, *dn, *alias;
 347         struct udev_list_entry *item = NULL, *first = NULL;
 348         int r;
 349
 350         assert(m);
 351
 352         sysfs = udev_device_get_syspath(dev);
 353         if (!sysfs)
 354                 return 0;
 355
 356         /* Add the main unit named after the sysfs path */
 357         r = device_update_unit(m, dev, sysfs, true);
 358         if (r < 0)
 359                 return r;
 360
 361         /* Add an additional unit for the device node */
 362         dn = udev_device_get_devnode(dev);
 363         if (dn)
 364                 device_update_unit(m, dev, dn, false);
 365
 366         /* Add additional units for all symlinks */
 367         first = udev_device_get_devlinks_list_entry(dev);
 368         udev_list_entry_foreach(item, first) {
 369                 const char *p;
 370                 struct stat st;
 371
 372                 /* Don't bother with the /dev/block links */
 373                 p = udev_list_entry_get_name(item);
 374
 375                 if (path_startswith(p, "/dev/block/") ||
 376                     path_startswith(p, "/dev/char/"))
 377                         continue;
 378
 379                 /* Verify that the symlink in the FS actually belongs
 380                  * to this device. This is useful to deal with
 381                  * conflicting devices, e.g. when two disks want the
 382                  * same /dev/disk/by-label/xxx link because they have
 383                  * the same label. We want to make sure that the same
 384                  * device that won the symlink wins in systemd, so we
 385                  * check the device node major/minor*/
 386                 if (stat(p, &st) >= 0)
 387                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
 388                             st.st_rdev != udev_device_get_devnum(dev))
 389                                 continue;
 390
 391                 device_update_unit(m, dev, p, false);
 392         }
 393
 394         /* Add additional units for all explicitly configured
 395          * aliases */
 396         alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
 397         if (alias) {
 398                 const char *word, *state;
 399                 size_t l;
 400
 401                 FOREACH_WORD_QUOTED(word, l, alias, state) {
 402                         char e[l+1];
 403
 404                         memcpy(e, word, l);
 405                         e[l] = 0;
 406
 407                         if (path_is_absolute(e))
 408                                 device_update_unit(m, dev, e, false);
 409                         else
 410                                 log_warning("SYSTEMD_ALIAS for %s is not an absolute path, ignoring: %s", sysfs, e);
 411                 }
 412                 if (!isempty(state))
 413                         log_warning("SYSTEMD_ALIAS for %s has trailing garbage, ignoring.", sysfs);
 414         }
 415
 416         return 0;
 417 }
 418
 419 static void device_set_path_plugged(Manager *m, struct udev_device *dev) {
 420         const char *sysfs;
 421         Device *d, *l;
 422
 423         assert(m);
 424         assert(dev);
 425
 426         sysfs = udev_device_get_syspath(dev);
 427         if (!sysfs)
 428                 return;
 429
 430         l = hashmap_get(m->devices_by_sysfs, sysfs);
 431         LIST_FOREACH(same_sysfs, d, l)
 432                 device_set_state(d, DEVICE_PLUGGED);
 433 }
 434
 435 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 436         const char *sysfs;
 437         Device *d;
 438
 439         assert(m);
 440         assert(dev);
 441
 442         sysfs = udev_device_get_syspath(dev);
 443         if (!sysfs)
 444                 return -ENOMEM;
 445
 446         /* Remove all units of this sysfs path */
 447         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 448                 device_unset_sysfs(d);
 449                 device_set_state(d, DEVICE_DEAD);
 450         }
 451
 452         return 0;
 453 }
 454
 455 static bool device_is_ready(struct udev_device *dev) {
 456         const char *ready;
 457
 458         assert(dev);
 459
 460         ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
 461         if (!ready)
 462                 return true;
 463
 464         return parse_boolean(ready) != 0;
 465 }
 466
 467 static int device_process_new_path(Manager *m, const char *path) {
 468         _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
 469
 470         assert(m);
 471         assert(path);
 472
 473         dev = udev_device_new_from_syspath(m->udev, path);
 474         if (!dev)
 475                 return log_oom();
 476
 477         if (!device_is_ready(dev))
 478                 return 0;
 479
 480         return device_process_new_device(m, dev);
 481 }
 482
 483 static Unit *device_following(Unit *u) {
 484         Device *d = DEVICE(u);
 485         Device *other, *first = NULL;
 486
 487         assert(d);
 488
 489         if (startswith(u->id, "sys-"))
 490                 return NULL;
 491
 492         /* Make everybody follow the unit that's named after the sysfs path */
 493         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 494                 if (startswith(UNIT(other)->id, "sys-"))
 495                         return UNIT(other);
 496
 497         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 498                 if (startswith(UNIT(other)->id, "sys-"))
 499                         return UNIT(other);
 500
 501                 first = other;
 502         }
 503
 504         return UNIT(first);
 505 }
 506
 507 static int device_following_set(Unit *u, Set **_set) {
 508         Device *d = DEVICE(u), *other;
 509         Set *set;
 510         int r;
 511
 512         assert(d);
 513         assert(_set);
 514
 515         if (LIST_JUST_US(same_sysfs, d)) {
 516                 *_set = NULL;
 517                 return 0;
 518         }
 519
 520         set = set_new(NULL);
 521         if (!set)
 522                 return -ENOMEM;
 523
 524         LIST_FOREACH_AFTER(same_sysfs, other, d) {
 525                 r = set_put(set, other);
 526                 if (r < 0)
 527                         goto fail;
 528         }
 529
 530         LIST_FOREACH_BEFORE(same_sysfs, other, d) {
 531                 r = set_put(set, other);
 532                 if (r < 0)
 533                         goto fail;
 534         }
 535
 536         *_set = set;
 537         return 1;
 538
 539 fail:
 540         set_free(set);
 541         return r;
 542 }
 543
 544 static void device_shutdown(Manager *m) {
 545         assert(m);
 546
 547         m->udev_event_source = sd_event_source_unref(m->udev_event_source);
 548
 549         if (m->udev_monitor) {
 550                 udev_monitor_unref(m->udev_monitor);
 551                 m->udev_monitor = NULL;
 552         }
 553
 554         hashmap_free(m->devices_by_sysfs);
 555         m->devices_by_sysfs = NULL;
 556 }
 557
 558 static int device_enumerate(Manager *m) {
 559         _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
 560         struct udev_list_entry *item = NULL, *first = NULL;
 561         int r;
 562
 563         assert(m);
 564
 565         if (!m->udev_monitor) {
 566                 m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev");
 567                 if (!m->udev_monitor) {
 568                         r = -ENOMEM;
 569                         goto fail;
 570                 }
 571
 572                 /* This will fail if we are unprivileged, but that
 573                  * should not matter much, as user instances won't run
 574                  * during boot. */
 575                 udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);
 576
 577                 r = udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd");
 578                 if (r < 0)
 579                         goto fail;
 580
 581                 r = udev_monitor_enable_receiving(m->udev_monitor);
 582                 if (r < 0)
 583                         goto fail;
 584
 585                 r = sd_event_add_io(m->event, &m->udev_event_source, udev_monitor_get_fd(m->udev_monitor), EPOLLIN, device_dispatch_io, m);
 586                 if (r < 0)
 587                         goto fail;
 588         }
 589
 590         e = udev_enumerate_new(m->udev);
 591         if (!e) {
 592                 r = -ENOMEM;
 593                 goto fail;
 594         }
 595
 596         r = udev_enumerate_add_match_tag(e, "systemd");
 597         if (r < 0)
 598                 goto fail;
 599
 600         r = udev_enumerate_add_match_is_initialized(e);
 601         if (r < 0)
 602                 goto fail;
 603
 604         r = udev_enumerate_scan_devices(e);
 605         if (r < 0)
 606                 goto fail;
 607
 608         first = udev_enumerate_get_list_entry(e);
 609         udev_list_entry_foreach(item, first)
 610                 device_process_new_path(m, udev_list_entry_get_name(item));
 611
 612         return 0;
 613
 614 fail:
 615         device_shutdown(m);
 616         return r;
 617 }
 618
 619 static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
 620         _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
 621         Manager *m = userdata;
 622         const char *action;
 623         int r;
 624
 625         assert(m);
 626
 627         if (revents != EPOLLIN) {
 628                 static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);
 629
 630                 if (!ratelimit_test(&limit))
 631                         log_error("Failed to get udev event: %m");
 632                 if (!(revents & EPOLLIN))
 633                         return 0;
 634         }
 635
 636         /*
 637          * libudev might filter-out devices which pass the bloom
 638          * filter, so getting NULL here is not necessarily an error.
 639          */
 640         dev = udev_monitor_receive_device(m->udev_monitor);
 641         if (!dev)
 642                 return 0;
 643
 644         action = udev_device_get_action(dev);
 645         if (!action) {
 646                 log_error("Failed to get udev action string.");
 647                 return 0;
 648         }
 649
 650         if (streq(action, "remove") || !device_is_ready(dev))  {
 651                 r = device_process_removed_device(m, dev);
 652                 if (r < 0)
 653                         log_error("Failed to process device remove event: %s", strerror(-r));
 654
 655                 r = swap_process_removed_device(m, dev);
 656                 if (r < 0)
 657                         log_error("Failed to process swap device remove event: %s", strerror(-r));
 658
 659         } else {
 660                 r = device_process_new_device(m, dev);
 661                 if (r < 0)
 662                         log_error("Failed to process device new event: %s", strerror(-r));
 663
 664                 r = swap_process_new_device(m, dev);
 665                 if (r < 0)
 666                         log_error("Failed to process swap device new event: %s", strerror(-r));
 667
 668                 manager_dispatch_load_queue(m);
 669
 670                 device_set_path_plugged(m, dev);
 671         }
 672
 673         return 0;
 674 }
 675
 676 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 677         [DEVICE_DEAD] = "dead",
 678         [DEVICE_PLUGGED] = "plugged"
 679 };
 680
 681 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 682
 683 const UnitVTable device_vtable = {
 684         .object_size = sizeof(Device),
 685         .sections =
 686                 "Unit\0"
 687                 "Device\0"
 688                 "Install\0",
 689
 690         .no_instances = true,
 691
 692         .init = device_init,
 693         .done = device_done,
 694         .load = unit_load_fragment_and_dropin_optional,
 695
 696         .coldplug = device_coldplug,
 697
 698         .dump = device_dump,
 699
 700         .active_state = device_active_state,
 701         .sub_state_to_string = device_sub_state_to_string,
 702
 703         .bus_interface = "org.freedesktop.systemd1.Device",
 704         .bus_vtable = bus_device_vtable,
 705
 706         .following = device_following,
 707         .following_set = device_following_set,
 708
 709         .enumerate = device_enumerate,
 710         .shutdown = device_shutdown,
 711
 712         .status_message_formats = {
 713                 .starting_stopping = {
 714                         [0] = "Expecting device %s...",
 715                 },
 716                 .finished_start_job = {
 717                         [JOB_DONE]       = "Found device %s.",
 718                         [JOB_TIMEOUT]    = "Timed out waiting for device %s.",
 719                 },
 720         },
 721 };