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