src/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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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
  34 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  35         [DEVICE_DEAD] = UNIT_INACTIVE,
  36         [DEVICE_PLUGGED] = UNIT_ACTIVE
  37 };
  38
  39 static void device_unset_sysfs(Device *d) {
  40         Device *first;
  41
  42         assert(d);
  43
  44         if (!d->sysfs)
  45                 return;
  46
  47         /* Remove this unit from the chain of devices which share the
  48          * same sysfs path. */
  49         first = hashmap_get(d->meta.manager->devices_by_sysfs, d->sysfs);
  50         LIST_REMOVE(Device, same_sysfs, first, d);
  51
  52         if (first)
  53                 hashmap_remove_and_replace(d->meta.manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  54         else
  55                 hashmap_remove(d->meta.manager->devices_by_sysfs, d->sysfs);
  56
  57         free(d->sysfs);
  58         d->sysfs = NULL;
  59 }
  60
  61 static void device_init(Unit *u) {
  62         Device *d = DEVICE(u);
  63
  64         assert(d);
  65         assert(d->meta.load_state == UNIT_STUB);
  66
  67         /* In contrast to all other unit types we timeout jobs waiting
  68          * for devices by default. This is because they otherwise wait
  69          * indefinitely for plugged in devices, something which cannot
  70          * happen for the other units since their operations time out
  71          * anyway. */
  72         d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
  73 }
  74
  75 static void device_done(Unit *u) {
  76         Device *d = DEVICE(u);
  77
  78         assert(d);
  79
  80         device_unset_sysfs(d);
  81 }
  82
  83 static void device_set_state(Device *d, DeviceState state) {
  84         DeviceState old_state;
  85         assert(d);
  86
  87         old_state = d->state;
  88         d->state = state;
  89
  90         if (state != old_state)
  91                 log_debug("%s changed %s -> %s",
  92                           d->meta.id,
  93                           device_state_to_string(old_state),
  94                           device_state_to_string(state));
  95
  96         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true);
  97 }
  98
  99 static int device_coldplug(Unit *u) {
 100         Device *d = DEVICE(u);
 101
 102         assert(d);
 103         assert(d->state == DEVICE_DEAD);
 104
 105         if (d->sysfs)
 106                 device_set_state(d, DEVICE_PLUGGED);
 107
 108         return 0;
 109 }
 110
 111 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 112         Device *d = DEVICE(u);
 113
 114         assert(d);
 115
 116         fprintf(f,
 117                 "%sDevice State: %s\n"
 118                 "%sSysfs Path: %s\n",
 119                 prefix, device_state_to_string(d->state),
 120                 prefix, strna(d->sysfs));
 121 }
 122
 123 static UnitActiveState device_active_state(Unit *u) {
 124         assert(u);
 125
 126         return state_translation_table[DEVICE(u)->state];
 127 }
 128
 129 static const char *device_sub_state_to_string(Unit *u) {
 130         assert(u);
 131
 132         return device_state_to_string(DEVICE(u)->state);
 133 }
 134
 135 static int device_add_escaped_name(Unit *u, const char *dn) {
 136         char *e;
 137         int r;
 138
 139         assert(u);
 140         assert(dn);
 141         assert(dn[0] == '/');
 142
 143         if (!(e = unit_name_from_path(dn, ".device")))
 144                 return -ENOMEM;
 145
 146         r = unit_add_name(u, e);
 147         free(e);
 148
 149         if (r < 0 && r != -EEXIST)
 150                 return r;
 151
 152         return 0;
 153 }
 154
 155 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 156         char *e;
 157         Unit *u;
 158
 159         assert(m);
 160         assert(dn);
 161         assert(dn[0] == '/');
 162         assert(_u);
 163
 164         if (!(e = unit_name_from_path(dn, ".device")))
 165                 return -ENOMEM;
 166
 167         u = manager_get_unit(m, e);
 168         free(e);
 169
 170         if (u) {
 171                 *_u = u;
 172                 return 1;
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 179         const char *sysfs, *model;
 180         Unit *u = NULL;
 181         int r;
 182         bool delete;
 183
 184         assert(m);
 185
 186         if (!(sysfs = udev_device_get_syspath(dev)))
 187                 return -ENOMEM;
 188
 189         if ((r = device_find_escape_name(m, path, &u)) < 0)
 190                 return r;
 191
 192         if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs))
 193                 return -EEXIST;
 194
 195         if (!u) {
 196                 delete = true;
 197
 198                 if (!(u = unit_new(m)))
 199                         return -ENOMEM;
 200
 201                 if ((r = device_add_escaped_name(u, path)) < 0)
 202                         goto fail;
 203
 204                 unit_add_to_load_queue(u);
 205         } else
 206                 delete = false;
 207
 208         /* If this was created via some dependency and has not
 209          * actually been seen yet ->sysfs will not be
 210          * initialized. Hence initialize it if necessary. */
 211
 212         if (!DEVICE(u)->sysfs) {
 213                 Device *first;
 214
 215                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
 216                         r = -ENOMEM;
 217                         goto fail;
 218                 }
 219
 220                 if (!m->devices_by_sysfs)
 221                         if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
 222                                 r = -ENOMEM;
 223                                 goto fail;
 224                         }
 225
 226                 first = hashmap_get(m->devices_by_sysfs, sysfs);
 227                 LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
 228
 229                 if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
 230                         goto fail;
 231         }
 232
 233         if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
 234             (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
 235                 if ((r = unit_set_description(u, model)) < 0)
 236                         goto fail;
 237         } else
 238                 if ((r = unit_set_description(u, path)) < 0)
 239                         goto fail;
 240
 241         if (main) {
 242                 /* The additional systemd udev properties we only
 243                  * interpret for the main object */
 244                 const char *wants, *alias;
 245
 246                 if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
 247                         if (!is_path(alias))
 248                                 log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
 249                         else {
 250                                 if ((r = device_add_escaped_name(u, alias)) < 0)
 251                                         goto fail;
 252                         }
 253                 }
 254
 255                 if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
 256                         char *state, *w;
 257                         size_t l;
 258
 259                         FOREACH_WORD_QUOTED(w, l, wants, state) {
 260                                 char *e;
 261
 262                                 if (!(e = strndup(w, l))) {
 263                                         r = -ENOMEM;
 264                                         goto fail;
 265                                 }
 266
 267                                 r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
 268                                 free(e);
 269
 270                                 if (r < 0)
 271                                         goto fail;
 272                         }
 273                 }
 274         }
 275
 276         unit_add_to_dbus_queue(u);
 277         return 0;
 278
 279 fail:
 280         log_warning("Failed to load device unit: %s", strerror(-r));
 281
 282         if (delete && u)
 283                 unit_free(u);
 284
 285         return r;
 286 }
 287
 288 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
 289         const char *sysfs, *dn;
 290         struct udev_list_entry *item = NULL, *first = NULL;
 291
 292         assert(m);
 293
 294         if (!(sysfs = udev_device_get_syspath(dev)))
 295                 return -ENOMEM;
 296
 297         /* Add the main unit named after the sysfs path */
 298         device_update_unit(m, dev, sysfs, true);
 299
 300         /* Add an additional unit for the device node */
 301         if ((dn = udev_device_get_devnode(dev)))
 302                 device_update_unit(m, dev, dn, false);
 303
 304         /* Add additional units for all symlinks */
 305         first = udev_device_get_devlinks_list_entry(dev);
 306         udev_list_entry_foreach(item, first) {
 307                 const char *p;
 308                 struct stat st;
 309
 310                 /* Don't bother with the /dev/block links */
 311                 p = udev_list_entry_get_name(item);
 312
 313                 if (path_startswith(p, "/dev/block/") ||
 314                     path_startswith(p, "/dev/char/"))
 315                         continue;
 316
 317                 /* Verify that the symlink in the FS actually belongs
 318                  * to this device. This is useful to deal with
 319                  * conflicting devices, e.g. when two disks want the
 320                  * same /dev/disk/by-label/xxx link because they have
 321                  * the same label. We want to make sure that the same
 322                  * device that won the symlink wins in systemd, so we
 323                  * check the device node major/minor*/
 324                 if (stat(p, &st) >= 0)
 325                         if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) ||
 326                             st.st_rdev != udev_device_get_devnum(dev))
 327                                 continue;
 328
 329                 device_update_unit(m, dev, p, false);
 330         }
 331
 332         if (update_state) {
 333                 Device *d, *l;
 334
 335                 manager_dispatch_load_queue(m);
 336
 337                 l = hashmap_get(m->devices_by_sysfs, sysfs);
 338                 LIST_FOREACH(same_sysfs, d, l)
 339                         device_set_state(d, DEVICE_PLUGGED);
 340         }
 341
 342         return 0;
 343 }
 344
 345 static int device_process_path(Manager *m, const char *path, bool update_state) {
 346         int r;
 347         struct udev_device *dev;
 348
 349         assert(m);
 350         assert(path);
 351
 352         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
 353                 log_warning("Failed to get udev device object from udev for path %s.", path);
 354                 return -ENOMEM;
 355         }
 356
 357         r = device_process_new_device(m, dev, update_state);
 358         udev_device_unref(dev);
 359         return r;
 360 }
 361
 362 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
 363         const char *sysfs;
 364         Device *d;
 365
 366         assert(m);
 367         assert(dev);
 368
 369         if (!(sysfs = udev_device_get_syspath(dev)))
 370                 return -ENOMEM;
 371
 372         /* Remove all units of this sysfs path */
 373         while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
 374                 device_unset_sysfs(d);
 375                 device_set_state(d, DEVICE_DEAD);
 376         }
 377
 378         return 0;
 379 }
 380
 381 static Unit *device_following(Unit *u) {
 382         Device *d = DEVICE(u);
 383         Device *other, *first = NULL;
 384
 385         assert(d);
 386
 387         if (startswith(u->meta.id, "sys-"))
 388                 return NULL;
 389
 390         /* Make everybody follow the unit that's named after the sysfs path */
 391         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 392                 if (startswith(other->meta.id, "sys-"))
 393                         return UNIT(other);
 394
 395         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
 396                 if (startswith(other->meta.id, "sys-"))
 397                         return UNIT(other);
 398
 399                 first = other;
 400         }
 401
 402         return UNIT(first);
 403 }
 404
 405 static int device_following_set(Unit *u, Set **_s) {
 406         Device *d = DEVICE(u);
 407         Device *other;
 408         Set *s;
 409         int r;
 410
 411         assert(d);
 412         assert(_s);
 413
 414         if (!d->same_sysfs_prev && !d->same_sysfs_next) {
 415                 *_s = NULL;
 416                 return 0;
 417         }
 418
 419         if (!(s = set_new(NULL, NULL)))
 420                 return -ENOMEM;
 421
 422         for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
 423                 if ((r = set_put(s, other)) < 0)
 424                         goto fail;
 425
 426         for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev)
 427                 if ((r = set_put(s, other)) < 0)
 428                         goto fail;
 429
 430         *_s = s;
 431         return 1;
 432
 433 fail:
 434         set_free(s);
 435         return r;
 436 }
 437
 438 static void device_shutdown(Manager *m) {
 439         assert(m);
 440
 441         if (m->udev_monitor) {
 442                 udev_monitor_unref(m->udev_monitor);
 443                 m->udev_monitor = NULL;
 444         }
 445
 446         if (m->udev) {
 447                 udev_unref(m->udev);
 448                 m->udev = NULL;
 449         }
 450
 451         hashmap_free(m->devices_by_sysfs);
 452         m->devices_by_sysfs = NULL;
 453 }
 454
 455 static int device_enumerate(Manager *m) {
 456         struct epoll_event ev;
 457         int r;
 458         struct udev_enumerate *e = NULL;
 459         struct udev_list_entry *item = NULL, *first = NULL;
 460
 461         assert(m);
 462
 463         if (!m->udev) {
 464                 if (!(m->udev = udev_new()))
 465                         return -ENOMEM;
 466
 467                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 468                         r = -ENOMEM;
 469                         goto fail;
 470                 }
 471
 472                 /* This will fail if we are unprivileged, but that
 473                  * should not matter much, as user instances won't run
 474                  * during boot. */
 475                 udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024);
 476
 477                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 478                         r = -ENOMEM;
 479                         goto fail;
 480                 }
 481
 482                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 483                         r = -EIO;
 484                         goto fail;
 485                 }
 486
 487                 m->udev_watch.type = WATCH_UDEV;
 488                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 489
 490                 zero(ev);
 491                 ev.events = EPOLLIN;
 492                 ev.data.ptr = &m->udev_watch;
 493
 494                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 495                         return -errno;
 496         }
 497
 498         if (!(e = udev_enumerate_new(m->udev))) {
 499                 r = -ENOMEM;
 500                 goto fail;
 501         }
 502         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 503                 r = -EIO;
 504                 goto fail;
 505         }
 506
 507         if (udev_enumerate_scan_devices(e) < 0) {
 508                 r = -EIO;
 509                 goto fail;
 510         }
 511
 512         first = udev_enumerate_get_list_entry(e);
 513         udev_list_entry_foreach(item, first)
 514                 device_process_path(m, udev_list_entry_get_name(item), false);
 515
 516         udev_enumerate_unref(e);
 517         return 0;
 518
 519 fail:
 520         if (e)
 521                 udev_enumerate_unref(e);
 522
 523         device_shutdown(m);
 524         return r;
 525 }
 526
 527 void device_fd_event(Manager *m, int events) {
 528         struct udev_device *dev;
 529         int r;
 530         const char *action, *ready;
 531
 532         assert(m);
 533
 534         if (events != EPOLLIN) {
 535                 static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5);
 536
 537                 if (!ratelimit_test(&limit))
 538                         log_error("Failed to get udev event: %m");
 539                 if (!(events & EPOLLIN))
 540                         return;
 541         }
 542
 543         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 544                 /*
 545                  * libudev might filter-out devices which pass the bloom filter,
 546                  * so getting NULL here is not necessarily an error
 547                  */
 548                 return;
 549         }
 550
 551         if (!(action = udev_device_get_action(dev))) {
 552                 log_error("Failed to get udev action string.");
 553                 goto fail;
 554         }
 555
 556         ready = udev_device_get_property_value(dev, "SYSTEMD_READY");
 557
 558         if (streq(action, "remove") || (ready && parse_boolean(ready) == 0)) {
 559                 if ((r = device_process_removed_device(m, dev)) < 0) {
 560                         log_error("Failed to process udev device event: %s", strerror(-r));
 561                         goto fail;
 562                 }
 563         } else {
 564                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 565                         log_error("Failed to process udev device event: %s", strerror(-r));
 566                         goto fail;
 567                 }
 568         }
 569
 570 fail:
 571         udev_device_unref(dev);
 572 }
 573
 574 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 575         [DEVICE_DEAD] = "dead",
 576         [DEVICE_PLUGGED] = "plugged"
 577 };
 578
 579 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 580
 581 const UnitVTable device_vtable = {
 582         .suffix = ".device",
 583
 584         .no_instances = true,
 585         .no_snapshots = true,
 586         .no_isolate = true,
 587
 588         .init = device_init,
 589
 590         .load = unit_load_fragment_and_dropin_optional,
 591         .done = device_done,
 592         .coldplug = device_coldplug,
 593
 594         .dump = device_dump,
 595
 596         .active_state = device_active_state,
 597         .sub_state_to_string = device_sub_state_to_string,
 598
 599         .bus_interface = "org.freedesktop.systemd1.Device",
 600         .bus_message_handler = bus_device_message_handler,
 601         .bus_invalidating_properties =  bus_device_invalidating_properties,
 602
 603         .following = device_following,
 604         .following_set = device_following_set,
 605
 606         .enumerate = device_enumerate,
 607         .shutdown = device_shutdown
 608 };