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