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 "unit.h"
  27 #include "device.h"
  28 #include "strv.h"
  29 #include "log.h"
  30 #include "unit-name.h"
  31 #include "dbus-device.h"
  32 #include "def.h"
  33 #include "path-util.h"
  34
  35 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  36         [DEVICE_DEAD] = UNIT_INACTIVE,
  37         [DEVICE_PLUGGED] = UNIT_ACTIVE
  38 };
  39
  40 static void device_unset_sysfs(Device *d) {
  41         Device *first;
  42
  43         assert(d);
  44
  45         if (!d->sysfs)
  46                 return;
  47
  48         /* Remove this unit from the chain of devices which share the
  49          * same sysfs path. */
  50         first = hashmap_get(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
  51         LIST_REMOVE(Device, same_sysfs, first, d);
  52
  53         if (first)
  54                 hashmap_remove_and_replace(UNIT(d)->manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  55         else
  56                 hashmap_remove(UNIT(d)->manager->devices_by_sysfs, d->sysfs);
  57
  58         free(d->sysfs);
  59         d->sysfs = NULL;
  60 }
  61
  62 static void device_init(Unit *u) {
  63         Device *d = DEVICE(u);
  64
  65         assert(d);
  66         assert(UNIT(d)->load_state == UNIT_STUB);
  67
  68         /* In contrast to all other unit types we timeout jobs waiting
  69          * for devices by default. This is because they otherwise wait
  70          * indefinitely for plugged in devices, something which cannot
  71          * happen for the other units since their operations time out
  72          * anyway. */
  73         UNIT(d)->job_timeout = DEFAULT_TIMEOUT_USEC;
  74
  75         UNIT(d)->ignore_on_isolate = true;
  76         UNIT(d)->ignore_on_snapshot = true;
  77 }
  78
  79 static void device_done(Unit *u) {
  80         Device *d = DEVICE(u);
  81
  82         assert(d);
  83
  84         device_unset_sysfs(d);
  85 }
  86
  87 static void device_set_state(Device *d, DeviceState state) {
  88         DeviceState old_state;
  89         assert(d);
  90
  91         old_state = d->state;
  92         d->state = state;
  93
  94         if (state != old_state)
  95                 log_debug("%s changed %s -> %s",
  96                           UNIT(d)->id,
  97                           device_state_to_string(old_state),
  98                           device_state_to_string(state));
  99
 100         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
 101 }
 102
 103 static int device_coldplug(Unit *u) {
 104         Device *d = DEVICE(u);
 105
 106         assert(d);
 107         assert(d->state == DEVICE_DEAD);
 108
 109         if (d->sysfs)
 110                 device_set_state(d, DEVICE_PLUGGED);
 111
 112         return 0;
 113 }
 114
 115 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 116         Device *d = DEVICE(u);
 117
 118         assert(d);
 119
 120         fprintf(f,
 121                 "%sDevice State: %s\n"
 122                 "%sSysfs Path: %s\n",
 123                 prefix, device_state_to_string(d->state),
 124                 prefix, strna(d->sysfs));
 125 }
 126
 127 static UnitActiveState device_active_state(Unit *u) {
 128         assert(u);
 129
 130         return state_translation_table[DEVICE(u)->state];
 131 }
 132
 133 static const char *device_sub_state_to_string(Unit *u) {
 134         assert(u);
 135
 136         return device_state_to_string(DEVICE(u)->state);
 137 }
 138
 139 static int device_add_escaped_name(Unit *u, const char *dn) {
 140         char *e;
 141         int r;
 142
 143         assert(u);
 144         assert(dn);
 145         assert(dn[0] == '/');
 146
 147         e = unit_name_from_path(dn, ".device");
 148         if (!e)
 149                 return -ENOMEM;
 150
 151         r = unit_add_name(u, e);
 152         free(e);
 153
 154         if (r < 0 && r != -EEXIST)
 155                 return r;
 156
 157         return 0;
 158 }
 159
 160 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 161         char *e;
 162         Unit *u;
 163
 164         assert(m);
 165         assert(dn);
 166         assert(dn[0] == '/');
 167         assert(_u);
 168
 169         e = unit_name_from_path(dn, ".device");
 170         if (!e)
 171                 return -ENOMEM;
 172
 173         u = manager_get_unit(m, e);
 174         free(e);
 175
 176         if (u) {
 177                 *_u = u;
 178                 return 1;
 179         }
 180
 181         return 0;
 182 }
 183
 184 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 185         const char *sysfs, *model;
 186         Unit *u = NULL;
 187         int r;
 188         bool delete;
 189
 190         assert(m);
 191
 192         if (!(sysfs = udev_device_get_syspath(dev)))
 193                 return -ENOMEM;
 194
 195         if ((r = device_find_escape_name(m, path, &u)) < 0)
 196                 return r;
 197
 198         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 199                 return -EEXIST;
 200
 201         if (!u) {
 202                 delete = true;
 203
 204                 u = unit_new(m, sizeof(Device));
 205                 if (!u)
 206                         return -ENOMEM;
 207
 208                 r = device_add_escaped_name(u, path);
 209                 if (r < 0)
 210                         goto fail;
 211
 212                 unit_add_to_load_queue(u);
 213         } else
 214                 delete = false;
 215
 216         /* If this was created via some dependency and has not
 217          * actually been seen yet ->sysfs will not be
 218          * initialized. Hence initialize it if necessary. */
 219
 220         if (!DEVICE(u)->sysfs) {
 221                 Device *first;
 222
 223                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 224                         r = -ENOMEM;
 225                         goto fail;
 226                 }
 227
 228                 if (!m->devices_by_sysfs)
 229                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 230                                 r = -ENOMEM;
 231                                 goto fail;
 232                         }
 233
 234                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 235                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 236
 237                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 238                         goto fail;
 239         }
 240
 241         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 242             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 243                 if ((r = unit_set_description(u, model)) < 0)
 244                         goto fail;
 245         } else
 246                 if ((r = unit_set_description(u, path)) < 0)
 247                         goto fail;
 248
 249         if (main) {
 250                 /* The additional systemd udev properties we only
 251                  * interpret for the main object */
 252                 const char *wants, *alias;
 253
 254                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 255                         if (!is_path(alias))
 256                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 257                         else {
 258                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 259                                         goto fail;
 260                         }
 261                 }
 262
 263                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 264                         char *state, *w;
 265                         size_t l;
 266
 267                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 268                                 char *e;
 269
 270                                 if (!(e = strndup(w, l))) {
 271                                         r = -ENOMEM;
 272                                         goto fail;
 273                                 }
 274
 275                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 276                                 free(e);
 277
 278                                 if (r < 0)
 279                                         goto fail;
 280                         }
 281                 }
 282         }
 283
 284         unit_add_to_dbus_queue(u);
 285         return 0;
 286
 287 fail:
 288         log_warning("Failed to load device unit: %s", strerror(-r));
 289
 290         if (delete && u)
 291                 unit_free(u);
 292
 293         return r;
 294 }
 295
 296 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 297         const char *sysfs, *dn;
 298         struct udev_list_entry *item = NULL, *first = NULL;
 299
 300         assert(m);
 301
 302         if (!(sysfs = udev_device_get_syspath(dev)))
 303                 return -ENOMEM;
 304
 305         /* Add the main unit named after the sysfs path */
 306         device_update_unit(m, dev, sysfs, true);
 307
 308         /* Add an additional unit for the device node */
 309         if ((dn = udev_device_get_devnode(dev)))
 310                 device_update_unit(m, dev, dn, false);
 311
 312         /* Add additional units for all symlinks */
 313         first = udev_device_get_devlinks_list_entry(dev);
 314         udev_list_entry_foreach(item, first) {
 315                 const char *p;
 316                 struct stat st;
 317
 318                 /* Don't bother with the /dev/block links */
 319                 p = udev_list_entry_get_name(item);
 320
 321                 if (path_startswith(p, "/dev/block/") ||
 322                     path_startswith(p, "/dev/char/"))
 323                         continue;
 324
 325                 /* Verify that the symlink in the FS actually belongs
 326                  * to this device. This is useful to deal with
 327                  * conflicting devices, e.g. when two disks want the
 328                  * same /dev/disk/by-label/xxx link because they have
 329                  * the same label. We want to make sure that the same
 330                  * device that won the symlink wins in systemd, so we
 331                  * check the device node major/minor*/
 332                 if (stat(p, &st) >= 0)
 333                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
 334                             st.st_rdev != udev_device_get_devnum(dev))
 335                                 continue;
 336
 337                 device_update_unit(m, dev, p, false);
 338         }
 339
 340         if (update_state) {
 341                 Device *d, *l;
 342
 343                 manager_dispatch_load_queue(m);
 344
 345                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 346                 LIST_FOREACH(same_sysfs, d, l)
 347                         device_set_state(d, DEVICE_PLUGGED);
 348         }
 349
 350         return 0;
 351 }
 352
 353 static int device_process_path(Manager *m, const char *path, bool update_state) {
 354         int r;
 355         struct udev_device *dev;
 356
 357         assert(m);
 358         assert(path);
 359
 360         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 361                 log_warning("Failed to get udev device object from udev for path %s.", path);
 362                 return -ENOMEM;
 363         }
 364
 365         r = device_process_new_device(m, dev, update_state);
 366         udev_device_unref(dev);
 367         return r;
 368 }
 369
 370 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 371         const char *sysfs;
 372         Device *d;
 373
 374         assert(m);
 375         assert(dev);
 376
 377         if (!(sysfs = udev_device_get_syspath(dev)))
 378                 return -ENOMEM;
 379
 380         /* Remove all units of this sysfs path */
 381         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 382                 device_unset_sysfs(d);
 383                 device_set_state(d, DEVICE_DEAD);
 384         }
 385
 386         return 0;
 387 }
 388
 389 static Unit *device_following(Unit *u) {
 390         Device *d = DEVICE(u);
 391         Device *other, *first = NULL;
 392
 393         assert(d);
 394
 395         if (startswith(u->id, "sys-"))
 396                 return NULL;
 397
 398         /* Make everybody follow the unit that's named after the sysfs path */
 399         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 400                 if (startswith(UNIT(other)->id, "sys-"))
 401                         return UNIT(other);
 402
 403         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 404                 if (startswith(UNIT(other)->id, "sys-"))
 405                         return UNIT(other);
 406
 407                 first = other;
 408         }
 409
 410         return UNIT(first);
 411 }
 412
 413 static int device_following_set(Unit *u, Set **_s) {
 414         Device *d = DEVICE(u);
 415         Device *other;
 416         Set *s;
 417         int r;
 418
 419         assert(d);
 420         assert(_s);
 421
 422         if (!d->same_sysfs_prev && !d->same_sysfs_next) {
 423                 *_s = NULL;
 424                 return 0;
 425         }
 426
 427         if (!(s = set_new(NULL, NULL)))
 428                 return -ENOMEM;
 429
 430         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 431                 if ((r = set_put(s, other)) < 0)
 432                         goto fail;
 433
 434         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev)
 435                 if ((r = set_put(s, other)) < 0)
 436                         goto fail;
 437
 438         *_s = s;
 439         return 1;
 440
 441 fail:
 442         set_free(s);
 443         return r;
 444 }
 445
 446 static void device_shutdown(Manager *m) {
 447         assert(m);
 448
 449         if (m->udev_monitor) {
 450                 udev_monitor_unref(m->udev_monitor);
 451                 m->udev_monitor = NULL;
 452         }
 453
 454         if (m->udev) {
 455                 udev_unref(m->udev);
 456                 m->udev = NULL;
 457         }
 458
 459         hashmap_free(m->devices_by_sysfs);
 460         m->devices_by_sysfs = NULL;
 461 }
 462
 463 static int device_enumerate(Manager *m) {
 464         struct epoll_event ev;
 465         int r;
 466         struct udev_enumerate *e = NULL;
 467         struct udev_list_entry *item = NULL, *first = NULL;
 468
 469         assert(m);
 470
 471         if (!m->udev) {
 472                 if (!(m->udev = udev_new()))
 473                         return -ENOMEM;
 474
 475                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 476                         r = -ENOMEM;
 477                         goto fail;
 478                 }
 479
 480                 /* This will fail if we are unprivileged, but that
 481                  * should not matter much, as user instances won't run
 482                  * during boot. */
 483                 udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);
 484
 485                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 486                         r = -ENOMEM;
 487                         goto fail;
 488                 }
 489
 490                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 491                         r = -EIO;
 492                         goto fail;
 493                 }
 494
 495                 m->udev_watch.type = WATCH_UDEV;
 496                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 497
 498                 zero(ev);
 499                 ev.events = EPOLLIN;
 500                 ev.data.ptr = &m->udev_watch;
 501
 502                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 503                         return -errno;
 504         }
 505
 506         if (!(e = udev_enumerate_new(m->udev))) {
 507                 r = -ENOMEM;
 508                 goto fail;
 509         }
 510         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 511                 r = -EIO;
 512                 goto fail;
 513         }
 514
 515         if (udev_enumerate_scan_devices(e) < 0) {
 516                 r = -EIO;
 517                 goto fail;
 518         }
 519
 520         first = udev_enumerate_get_list_entry(e);
 521         udev_list_entry_foreach(item, first)
 522                 device_process_path(m, udev_list_entry_get_name(item), false);
 523
 524         udev_enumerate_unref(e);
 525         return 0;
 526
 527 fail:
 528         if (e)
 529                 udev_enumerate_unref(e);
 530
 531         device_shutdown(m);
 532         return r;
 533 }
 534
 535 void device_fd_event(Manager *m, int events) {
 536         struct udev_device *dev;
 537         int r;
 538         const char *action, *ready;
 539
 540         assert(m);
 541
 542         if (events != EPOLLIN) {
 543                 static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);
 544
 545                 if (!ratelimit_test(&limit))
 546                         log_error("Failed to get udev event: %m");
 547                 if (!(events & EPOLLIN))
 548                         return;
 549         }
 550
 551         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 552                 /*
 553                  * libudev might filter-out devices which pass the bloom filter,
 554                  * so getting NULL here is not necessarily an error
 555                  */
 556                 return;
 557         }
 558
 559         if (!(action = udev_device_get_action(dev))) {
 560                 log_error("Failed to get udev action string.");
 561                 goto fail;
 562         }
 563
 564         ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
 565
 566         if (streq(action, "remove") || (ready && parse_boolean(ready) == 0)) {
 567                 if ((r = device_process_removed_device(m, dev)) < 0) {
 568                         log_error("Failed to process udev device event: %s", strerror(-r));
 569                         goto fail;
 570                 }
 571         } else {
 572                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 573                         log_error("Failed to process udev device event: %s", strerror(-r));
 574                         goto fail;
 575                 }
 576         }
 577
 578 fail:
 579         udev_device_unref(dev);
 580 }
 581
 582 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 583         [DEVICE_DEAD] = "dead",
 584         [DEVICE_PLUGGED] = "plugged"
 585 };
 586
 587 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 588
 589 const UnitVTable device_vtable = {
 590         .object_size = sizeof(Device),
 591         .sections =
 592                 "Unit\0"
 593                 "Device\0"
 594                 "Install\0",
 595
 596         .no_instances = true,
 597
 598         .init = device_init,
 599
 600         .load = unit_load_fragment_and_dropin_optional,
 601         .done = device_done,
 602         .coldplug = device_coldplug,
 603
 604         .dump = device_dump,
 605
 606         .active_state = device_active_state,
 607         .sub_state_to_string = device_sub_state_to_string,
 608
 609         .bus_interface = "org.freedesktop.systemd1.Device",
 610         .bus_message_handler = bus_device_message_handler,
 611         .bus_invalidating_properties =  bus_device_invalidating_properties,
 612
 613         .following = device_following,
 614         .following_set = device_following_set,
 615
 616         .enumerate = device_enumerate,
 617         .shutdown = device_shutdown,
 618
 619         .status_message_formats = {
 620                 .starting_stopping = {
 621                         [0] = "Expecting device %s...",
 622                 },
 623                 .finished_start_job = {
 624                         [JOB_DONE]       = "Found device %s.",
 625                         [JOB_TIMEOUT]    = "Timed out waiting for device %s.",
 626                 },
 627         },
 628 };