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
  33 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
  34         [DEVICE_DEAD] = UNIT_INACTIVE,
  35         [DEVICE_PLUGGED] = UNIT_ACTIVE
  36 };
  37
  38 static void device_unset_sysfs(Device *d) {
  39         Device *first;
  40
  41         assert(d);
  42
  43         if (!d->sysfs)
  44                 return;
  45
  46         /* Remove this unit from the chain of devices which share the
  47          * same sysfs path. */
  48         first = hashmap_get(d->meta.manager->devices_by_sysfs, d->sysfs);
  49         LIST_REMOVE(Device, same_sysfs, first, d);
  50
  51         if (first)
  52                 hashmap_remove_and_replace(d->meta.manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
  53         else
  54                 hashmap_remove(d->meta.manager->devices_by_sysfs, d->sysfs);
  55
  56         free(d->sysfs);
  57         d->sysfs = NULL;
  58 }
  59
  60 static void device_init(Unit *u) {
  61         Device *d = DEVICE(u);
  62
  63         assert(d);
  64         assert(d->meta.load_state == UNIT_STUB);
  65
  66         /* In contrast to all other unit types we timeout jobs waiting
  67          * for devices by default. This is because they otherwise wait
  68          * indefinetely for plugged in devices, something which cannot
  69          * happen for the other units since their operations time out
  70          * anyway. */
  71         d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
  72 }
  73
  74 static void device_done(Unit *u) {
  75         Device *d = DEVICE(u);
  76
  77         assert(d);
  78
  79         device_unset_sysfs(d);
  80 }
  81
  82 static void device_set_state(Device *d, DeviceState state) {
  83         DeviceState old_state;
  84         assert(d);
  85
  86         old_state = d->state;
  87         d->state = state;
  88
  89         if (state != old_state)
  90                 log_debug("%s changed %s -> %s",
  91                           d->meta.id,
  92                           device_state_to_string(old_state),
  93                           device_state_to_string(state));
  94
  95         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
  96 }
  97
  98 static int device_coldplug(Unit *u) {
  99         Device *d = DEVICE(u);
 100
 101         assert(d);
 102         assert(d->state == DEVICE_DEAD);
 103
 104         if (d->sysfs)
 105                 device_set_state(d, DEVICE_PLUGGED);
 106
 107         return 0;
 108 }
 109
 110 static void device_dump(Unit *u, FILE *f, const char *prefix) {
 111         Device *d = DEVICE(u);
 112
 113         assert(d);
 114
 115         fprintf(f,
 116                 "%sDevice State: %s\n"
 117                 "%sSysfs Path: %s\n",
 118                 prefix, device_state_to_string(d->state),
 119                 prefix, strna(d->sysfs));
 120 }
 121
 122 static UnitActiveState device_active_state(Unit *u) {
 123         assert(u);
 124
 125         return state_translation_table[DEVICE(u)->state];
 126 }
 127
 128 static const char *device_sub_state_to_string(Unit *u) {
 129         assert(u);
 130
 131         return device_state_to_string(DEVICE(u)->state);
 132 }
 133
 134 static int device_add_escaped_name(Unit *u, const char *dn) {
 135         char *e;
 136         int r;
 137
 138         assert(u);
 139         assert(dn);
 140         assert(dn[0] == '/');
 141
 142         if (!(e = unit_name_from_path(dn, ".device")))
 143                 return -ENOMEM;
 144
 145         r = unit_add_name(u, e);
 146         free(e);
 147
 148         if (r < 0 && r != -EEXIST)
 149                 return r;
 150
 151         return 0;
 152 }
 153
 154 static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
 155         char *e;
 156         Unit *u;
 157
 158         assert(m);
 159         assert(dn);
 160         assert(dn[0] == '/');
 161         assert(_u);
 162
 163         if (!(e = unit_name_from_path(dn, ".device")))
 164                 return -ENOMEM;
 165
 166         u = manager_get_unit(m, e);
 167         free(e);
 168
 169         if (u) {
 170                 *_u = u;
 171                 return 1;
 172         }
 173
 174         return 0;
 175 }
 176
 177 static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
 178         const char *sysfs, *model;
 179         Unit *u = NULL;
 180         int r;
 181         bool delete;
 182
 183         assert(m);
 184
 185         if (!(sysfs = udev_device_get_syspath(dev)))
 186                 return -ENOMEM;
 187
 188         if ((r = device_find_escape_name(m, path, &u)) < 0)
 189                 return r;
 190
 191         /* If a different unit already claimed this name then let's do
 192          * nothing. This can happen for example when two disks with
 193          * the same label are plugged in, and which hence try to get
 194          * conflicting symlinks in /dev/disk/by-label/xxxx */
 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 void device_shutdown(Manager *m) {
 409         assert(m);
 410
 411         if (m->udev_monitor) {
 412                 udev_monitor_unref(m->udev_monitor);
 413                 m->udev_monitor = NULL;
 414         }
 415
 416         if (m->udev) {
 417                 udev_unref(m->udev);
 418                 m->udev = NULL;
 419         }
 420
 421         hashmap_free(m->devices_by_sysfs);
 422         m->devices_by_sysfs = NULL;
 423 }
 424
 425 static int device_enumerate(Manager *m) {
 426         struct epoll_event ev;
 427         int r;
 428         struct udev_enumerate *e = NULL;
 429         struct udev_list_entry *item = NULL, *first = NULL;
 430
 431         assert(m);
 432
 433         if (!m->udev) {
 434                 if (!(m->udev = udev_new()))
 435                         return -ENOMEM;
 436
 437                 if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
 438                         r = -ENOMEM;
 439                         goto fail;
 440                 }
 441
 442                 if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
 443                         r = -ENOMEM;
 444                         goto fail;
 445                 }
 446
 447                 if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
 448                         r = -EIO;
 449                         goto fail;
 450                 }
 451
 452                 m->udev_watch.type = WATCH_UDEV;
 453                 m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
 454
 455                 zero(ev);
 456                 ev.events = EPOLLIN;
 457                 ev.data.ptr = &m->udev_watch;
 458
 459                 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
 460                         return -errno;
 461         }
 462
 463         if (!(e = udev_enumerate_new(m->udev))) {
 464                 r = -ENOMEM;
 465                 goto fail;
 466         }
 467         if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
 468                 r = -EIO;
 469                 goto fail;
 470         }
 471
 472         if (udev_enumerate_scan_devices(e) < 0) {
 473                 r = -EIO;
 474                 goto fail;
 475         }
 476
 477         first = udev_enumerate_get_list_entry(e);
 478         udev_list_entry_foreach(item, first)
 479                 device_process_path(m, udev_list_entry_get_name(item), false);
 480
 481         udev_enumerate_unref(e);
 482         return 0;
 483
 484 fail:
 485         if (e)
 486                 udev_enumerate_unref(e);
 487
 488         device_shutdown(m);
 489         return r;
 490 }
 491
 492 void device_fd_event(Manager *m, int events) {
 493         struct udev_device *dev;
 494         int r;
 495         const char *action;
 496
 497         assert(m);
 498         assert(events == EPOLLIN);
 499
 500         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
 501                 log_error("Failed to receive device.");
 502                 return;
 503         }
 504
 505         if (!(action = udev_device_get_action(dev))) {
 506                 log_error("Failed to get udev action string.");
 507                 goto fail;
 508         }
 509
 510         if (streq(action, "remove")) {
 511                 if ((r = device_process_removed_device(m, dev)) < 0) {
 512                         log_error("Failed to process udev device event: %s", strerror(-r));
 513                         goto fail;
 514                 }
 515         } else {
 516                 if ((r = device_process_new_device(m, dev, true)) < 0) {
 517                         log_error("Failed to process udev device event: %s", strerror(-r));
 518                         goto fail;
 519                 }
 520         }
 521
 522 fail:
 523         udev_device_unref(dev);
 524 }
 525
 526 static const char* const device_state_table[_DEVICE_STATE_MAX] = {
 527         [DEVICE_DEAD] = "dead",
 528         [DEVICE_PLUGGED] = "plugged"
 529 };
 530
 531 DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
 532
 533 const UnitVTable device_vtable = {
 534         .suffix = ".device",
 535
 536         .no_requires = true,
 537         .no_instances = true,
 538         .no_snapshots = true,
 539         .no_isolate = true,
 540
 541         .init = device_init,
 542
 543         .load = unit_load_fragment_and_dropin_optional,
 544         .done = device_done,
 545         .coldplug = device_coldplug,
 546
 547         .dump = device_dump,
 548
 549         .active_state = device_active_state,
 550         .sub_state_to_string = device_sub_state_to_string,
 551
 552         .bus_interface = "org.freedesktop.systemd1.Device",
 553         .bus_message_handler = bus_device_message_handler,
 554         .bus_invalidating_properties =  bus_device_invalidating_properties,
 555
 556         .following = device_following,
 557
 558         .enumerate = device_enumerate,
 559         .shutdown = device_shutdown
 560 };